Exercise is good for our health for many reasons. Regular exercise strengthens our heart and circulation. The heart is a muscle – the more we exercise it, the stronger it becomes. This allows it to pump blood around the body more efficiently, which can reduce the risk of cardiovascular disease. Our lungs also benefit: exercise makes us breathe deeper and our body learns to use oxygen more efficiently. It also stimulates our metabolism, which helps us maintain a healthy weight and reduces the risk of diabetes.
Not to mention the effect on our wellbeing: Exercise releases endorphins, reduces stress and can even help us sleep better. Regular exercise also strengthens muscles and joints, which can help prevent back pain and other ailments.
And it doesn’t have to be competitive sport. Even walking, cycling or dancing can help you stay healthy. The important thing is to keep moving and find something you enjoy.

Sound waves are mechanical waves that are generated by pressure fluctuations in a medium such as air.
Sound waves first hit the eardrum, causing it to vibrate. These vibrations are then transmitted to the auditory ossicles, which amplify them and transmit them to the inner ear.
The cochlea is located in the inner ear, where the hair cells convert the mechanical vibrations into electrical signals. This happens through the excitation of ion channels. The stimuli are then transmitted to the brain, which processes and interprets them. This enables us to understand speech, music and other sounds.
The conversion of sound waves into electrical signals first takes place in the head (more precisely in the inner ear) because several steps are necessary to convert mechanical information from the outside into a form that can be processed by the nervous system. The conversion takes place in a space that is as isolated as possible from environmental influences so that the process can take place independently of other mechanical vibrations, such as those triggered by muscle movements.

All of the body’s cells with a cell nucleus contain mitochondria. The special thing about heart and brain cells is that they contain a lot of mitochondria. This is because these cells have a particularly high energy consumption and the mitochondria are responsible for their energy supply as the “power plants of the cell”.

Critical questions are part of the scientific knowledge process and of the daily scientific exchange. For us scientists, it is also important to participate in controversial social debates in order to contribute scientific background and facts to the public discourse.

Dolphins are actually very intelligent animals and show some cognitive abilities similar to those of humans.
Their brains are large and highly convoluted, indicating a high level of intelligence.
Dolphins have an excellent memory and can exhibit complex social behaviors.
Some studies have shown that dolphins are able to recognize themselves in the mirror, which shows that they are self-aware.
They also communicate through a variety of sounds and can even use individual “names” to identify each other.
Although dolphins have impressive cognitive abilities, it is important to note that their way of thinking and intelligence is different to that of humans.
They are highly adapted to their environment and use their intelligence in a way that is optimal for their survival and social structures.

Our brain takes in a multitude of stimuli and sensory impressions, most of which we are not even aware of.
Through targeted learning, unconscious and conscious perceptions can be differentiated to a greater extent, with other areas of the brain coming into play than the mere processing of stimuli.
For example, exercises can improve the brain’s ability to process sounds and distinguish between different auditory stimuli.

Since in current research, leadership positions (e.g. professorships) are mainly held by men, although roughly the same number of women as men (or even slightly more women) are studying, there is currently mainly support for women in science, e.g. in the form of scholarships aimed exclusively at women.
Means to increase equal opportunities, such as for the compatibility of career and family, are open to all academics, regardless of gender, in times of intensive family obligations (caring for children or relatives).
In the area of career development, too, more and more support measures are being offered that are accessible to all female academics.

Scientific curiosity is often the driving force behind basic research aimed at gaining fundamental insights and expanding human knowledge.
Its significance for application is often not immediately apparent.
However, basic scientific research forms the basis for innovations and new technologies.
All applied research, such as the development of a drug, is based on fundamental knowledge.
Only if we understand how a disease develops can therapeutic approaches be developed to ultimately treat the disease.
It is therefore the task of basic research to understand the underlying mechanisms without directly targeting a therapeutic application.
Only with a fundamental understanding of what happens in a disease can applied research specifically search for effective substances.
Accordingly, basic research is the prerequisite for application-oriented developments and technical innovations.
In a risk-benefit analysis, dangers in research projects and clinical studies must be weighed up and possible ways of dealing with them explained, and discontinuation criteria must be defined for clinical studies.
Various control mechanisms also ensure compliance with the rules and minimization of the risks associated with the studies.

Building on knowledge-oriented basic research, health-relevant, benefit-oriented products such as pharmaceuticals may be developed, particularly in the medical field. It usually takes several years or even decades before these are approved. First, knowledge is generated and supplemented in basic research, or incorrect assumptions are discarded. This forms the basis for specific questions on practical issues, which can then lead to application in various steps – in the case of medical devices and medicinal products via preclinical and clinical studies. In some cases, the knowledge gained in this way is then adopted as a medicinal product or medical device for standard care. In the case of the heart patch, for example, around 25 years of preclinical research was followed by a lengthy animal experimentation phase before clinical research could begin, which has been ongoing for around two years and recently switched from the dose-finding phase to the proof-of-concept (PoC) phase. The heart patch is now being tested on a larger group of patients.

Clinical death is defined as the cessation of blood circulation and respiration, which are essential for maintaining life. This condition is usually determined by the absence of vital signs such as heartbeat and breathing. Clinical death can occur, for example, when a person suffers a cardiac arrest that results in a lack of oxygenated blood to the brain and other vital organs. In such cases, resuscitation may be possible within the first few minutes. It can also happen – albeit extremely rarely – that the circulation restarts spontaneously due to unknown physiological mechanisms or reflex reactions of the body. This event, known as the “Lazarus phenomenon” after the traditional resuscitation of Lazarus of Bethany by Jesus, is almost impossible after more than ten minutes of cardiac arrest. Biological death occurs as a result of clinical death that is not reversed by resuscitation. Breathing and circulation can also be maintained functionally by mechanical means (e.g. for organ removal for transplantation purposes) after clinical death. In this case, however, brain death is assumed before any organ removal takes place. To determine brain death, a series of complex examinations by independent doctors are necessary, such as the recording of an electroencephalogram (EEG), brain imaging, etc. This is subject to strict regulations. Brain death is irreversible, even if a brain-dead body can continue to be cared for mechanically by maintaining breathing and heartbeat.

The mechanisms that enable cats to hear are very similar to those of humans. However, cats have much better hearing than humans. They hear frequencies (pitches) from 20 Hz to 60,000 Hz (60 kHz), whereas humans can only perceive 16 to 20,000 hertz. By way of classification: the range between 500 and 4,000 Hertz is pleasant for us, and human speech or music, for example, is also in this range (depending on the volume, of course). This means that the cat hears many sounds that we cannot hear at all, e.g. a mouse in a mouse hole.

Communication includes not only the spoken word, but also gestures and body language, as well as other sensory impressions such as smell. For this reason, the question of whether it is possible to communicate with animals can be answered with a clear “yes”. If you look at dog owners or horse riders, for example, it is immediately clear that they communicate with their animals. However, they use a different language for this than when dogs communicate with each other, for example.

Animals communicate with their conspecifics in other ways: Through facial expressions, scents, sounds, etc. This usually involves the communication of immediate needs, moods, intentions or dangers.
Complex language, which goes beyond innate forms of expression, and abstract thoughts are nowhere more pronounced in the animal kingdom than in humans.

The nervous system is crucial for human survival as it plays a comprehensive role in regulating and coordinating various bodily processes: It acts as the body’s command center and controls all activities, from basic survival functions to complex cognitive tasks.
It integrates sensory information, processes it and generates appropriate responses to ensure that the body can react immediately to internal and external stimuli.
It also activates the fight-or-flight response and regulates important involuntary functions such as breathing, heartbeat, digestion and temperature control.
It also supports higher-level cognitive functions such as thinking, learning, memory formation and emotion regulation.
Without this ability, humans would not be able to interact meaningfully with their environment.

DNA (deoxyribonucleic acid), which contains genetic information, consists of long chains of nucleotides, the basic building blocks of genetic material. Each nucleotide consists of three main components: A phosphate group, a five-carbon sugar (deoxyribose in DNA) and a nitrogenous base (adenine, guanine, cytosine or thymine). Adenine and guanine are purines with a double ring structure. Cytosine and thymine are pyrimidines with a single ring structure. These bases pair specifically: adenine pairs with thymine, and guanine pairs with cytosine through hydrogen bonds and forms the rungs of the DNA ladder.

Communication between the brain and the heart is a constant dialog in which both organs send signals to each other via different channels – neurological pathways for immediate reactions, biochemical substances for regulatory effects and biophysical pressure waves for systemic coordination. Pain is a complex physiological and psychological experience that serves as a warning system for the body. It is caused by a series of processes involving tissue damage, nerve signals and interpretation by the brain: When an injury occurs, various chemical substances are released that sensitize the pain receptors (nerve endings located throughout the body), which then generate electrical impulses that are transmitted to various regions of the brain via the spinal cord by neurotransmitters. When the pain signals reach the brain, they are interpreted based on the context, previous experiences and emotional state. This interpretation can intensify or dampen the perception of pain. However, reflexes often occur before the pain is consciously perceived, causing the affected body part to move away from the source of the injury almost automatically and at lightning speed.

Traditionally, the soul is defined as an immaterial essence that embodies personal identity and consciousness. Plato, for example, held the view that the soul exists independently of the body and is immortal. He argued that true knowledge comes from the memory of what the soul knew before it entered a physical body. In many cultures, the soul, similar to Plato, is seen as a kind of spirit that “lives” in the body’s shell, often in certain organs, the bones or the blood. The heart, or in more modern conceptions the brain, is often regarded as the “dwelling place of the soul”. David Hume criticized the notion of a disembodied soul by arguing that there is no empirical evidence for its existence; he claimed that all phenomena can be explained by physical laws. Since there is still no definitive scientific evidence for the location of a non-physical entity such as the soul within our biological system, scientific opinion today tends to assume that it is biological conditions such as neuronal processes, shaped by cultural and interpersonal influences, that give rise to our consciousness, our feelings and our identity, and thus to what we generally refer to as the soul.

Many people have a so-called inner monologue, in which they talk “to themselves” in their head. This inner monologue helps us to process information, structure our thoughts and feelings and prepare for upcoming events.

Language is considered to be “typically human” and differs significantly in its complexity and structure from other forms of communication that we observe in animals. Nevertheless, we also find systems in animals that serve to exchange information. For example, chimpanzees have various calls with which they can warn their conspecifics of danger. Exactly how human language came about is still the subject of scientific research today. There is a consensus that the ability to speak did not arise as a result of a sudden change in the human genome, but has developed over a very long period of time in an interplay of genetic, anatomical and cultural factors. Two areas of the brain that are important for language processing and production, Broca’s and Wernicke’s areas, emerged around two million years ago. Symbolic and abstract language, which distinguishes human communication from the communication of apes, for example, probably only emerged around 30,000 to 40,000 years ago. The FOXP2 gene is often associated with the development of language.

The human body is a complex biological system. It is made up of various organ systems such as the nervous and circulatory systems. These organ systems are groups of organs (e.g. brain and heart), which in turn consist of different tissues such as muscle or nerve tissue. The tissues consist of cells that have specialized functions, such as heart muscle or nerve cells. A single human body has several trillion cells – the brain alone has almost 100 billion nerve cells.
At the elemental level, the human body consists mainly of hydrogen, oxygen and carbon. Together, these three elements make up almost 95% of the mass of the human body.

Creatures with two eyes have stereoscopic vision, which enables them to perceive depth and distance accurately. This is crucial for activities such as hunting, foraging and avoiding obstacles. People with only one eye can still see, but may have difficulty in accurately estimating distances and seeing “spatially” or three-dimensionally.
Accordingly, creatures with two ears can localize the source of sounds more precisely than those with one ear, enabling them to understand their surroundings and react appropriately. People with only one functioning ear can still hear, but may have difficulty determining the direction of sounds.

There are various reflexes in the brain that play a decisive role in maintaining homeostasis, i.e. the balance of the systems, and in reacting to stimuli. For example, an important reflex of the brain is the baroreceptor reflex. This reactively regulates blood pressure. This reflex is a complex interaction between the nervous system and the cardiovascular system to maintain an optimal blood pressure level.
The heart has intrinsic reflex mechanisms to adjust its rate depending on various factors such as physical activity, stress or hormonal influences. During exercise, for example, the sympathetic nervous system stimulates an increase in the heart rate in order to meet the muscles’ increased need for oxygen and nutrients. During periods of rest or relaxation, on the other hand, the parasympathetic nervous system reduces the heart rate and conserves energy.

The heart and brain work together via a complex communication and control system known as the heart-brain axis. The heart and brain influence each other’s functions through a variety of signals, including neuronal and hormonal pathways. This communication takes place via the nervous system.
The nervous system contains many billions of nerve cells (neurons).
Neurodegenerative disorders, vascular inflammation, traumatic injuries and other diseases can disrupt the cardiovascular system and lead to joint diseases of the heart and brain. In Takotsubo syndrome, for example, which is also being researched in Göttingen and is also known as “broken heart syndrome”, extreme emotional stress can lead to a sudden loss of heart function, which is symptomatically similar to a heart attack.

The human body is home to trillions of microorganisms, including bacteria, viruses, parasites and fungi. This collection of microorganisms is known as the human microbiome. Taken together, these organisms and their genetic material are more numerous than our own “human” cells. Our body has evolved over time to coexist with these microorganisms in a mutually beneficial relationship. Nevertheless, humans have their own DNA and cells, which make them unique and at the same time they cannot survive without the symbiosis with microorganisms.

Bluetooth technology is used for wireless communication over short distances between electronic devices such as smartphones, tablets, laptops or headphones.
Cells communicate with each other through a process known as cellular signaling. They exchange information through complex physical and biochemical processes. Signals from the environment or from neighboring cells are transmitted and trigger a reaction in the recipient cell. Cell communication is of crucial importance as it enables cells to work together as a team to achieve common goals such as maintaining the health of the organism. Cellular signal transmission in nerve and heart cells occurs primarily electrically through changes in the membrane potential of cells. The signal strength results from the frequency of the action potentials.
The study of cell signaling provides valuable insights into biological processes and diseases. Disturbances in cell signaling pathways can lead to pathological conditions characterized by abnormal cell proliferation or cell death. Understanding these mechanisms at the molecular level offers potential approaches for therapeutic interventions, for example in diseases of the heart or brain.

Arteries and veins are essential components of the circulatory system, which transports nutrients, oxygen and waste products between the cells and various organs of the body.
Arteries transport the blood away from the heart to the organs, while veins return the blood to the heart. These designations apply regardless of whether the blood in the respective vessel is oxygen-poor or oxygen-rich. Blood vessels form a widely ramified network, so-called anastomoses, which can ensure the blood supply even if smaller vessels fail.
Cells have no direct connection to arteries or veins, but are supplied via capillaries, which form a huge network that reaches every corner of the body and every single cell.
Oxygen and nutrients are exchanged with the cells by diffusion through the thin walls of the capillaries. This means that not every cell needs its own artery or vein.

When blood sugar levels drop due to hunger, this can trigger the release of stress hormones such as cortisol and adrenaline. These hormones are typically associated with the body’s fight-or-flight response. They can have an effect on the brain and lead to increased irritability and impulsiveness, which can manifest itself in feelings of anger, for example.

Diseases of the heart and brain are among the most common causes of death worldwide. Even though these two organs appear very different at first glance, heart and nerve cells have a surprising number of physiological similarities: Both consist of cells that cannot renew themselves and require a lot of energy. They consist of tiny components that work in a similar way and are part of electrical networks. Many diseases of the heart and brain are caused by disorders in these tiny components.

The aim of the Cluster of Excellence “Multiscale Bioimaging” is to understand these tiny components in heart and nerve cells. To achieve this, the researchers are looking at the heart and the brain at various levels – from the molecule to individual cells and cell networks to the entire organ. With the help of the latest innovative technologies and super-resolution microscopes, some of which were and are being developed in Göttingen, it is possible to better understand how the networks of the heart and brain work together.
With these findings, the Cluster of Excellence “Multiscale Bioimaging” can develop novel therapies for diseases of the heart, the brain or both organs.

Theoretically yes, but it is not easy to switch 2 or more “motors” in parallel. With everything the heart does (pump with gas pedal and brake), it is evolutionarily advantageous to have only one organ.

Research into the heart patch has been going on for over 15 years and has taken place at various locations. However, Göttingen was the best place for the transfer to clinical application. In addition to Lübeck, it is planned to find further locations for the application of the heart patches.

Yes, a patient who has had a heart patch sewn on must take immunosuppressants to suppress the body’s rejection reaction to the foreign tissue. The project “IndiHEART: Individualized heart muscle for the functional treatment of heart failure”, which is being carried out under the direction of the Institute of Pharmacology and Toxicology at the University Medical Center Göttingen, is in the process of developing hypoimmunogenic heart patches that require only minimal immunosuppression, as genes of the Major Histocompatibility Complex (MHC) have been removed from these cells.

A heart placed in an empty jar without any preservation measures (such as cooling or perfusion) cannot stay alive for more than a few minutes, as the cells die quickly due to a lack of oxygen and nutrients.
In medical practice, hearts removed for transplantation are usually stored in a cool place and treated with preservative solutions that delay cell degradation.
This procedure can prolong the viability of the heart for a maximum of 6 hours, but not if the heart is simply placed in an empty jar without preservation measures.

The function of the heart muscle results from the coordinated contraction of the sarcomeres, the smallest contractile units of the muscle in the cardiomyocytes, the heart muscle cells.
During each cardiac cycle, the sarcomere length changes from approx. 1.7 (systole) to approx. 2.3µm (diastole).
The muscle develops its maximum force at a sarcomere length of approx. 2.2µm (Frank-Starling mechanism).
In the beating heart, the muscle undergoes auxotonic contractions, i.e. the further it contracts, the greater the resistance (ventricular pressure).
In laboratory experiments, muscle force can be measured isometrically, i.e. at a constant length.
The length of the sarcomeres can be fixed experimentally in isometric measurements of tissue or single cells on very hard substrates, but not in vivo, i.e. in a living organism.

The heart patch theoretically lasts a lifetime.
Should it be broken down by an unexpected immune reaction or reinforced for medical reasons, further patches could be applied, but this has not yet been done.

The human heart is an organ consisting primarily of a hollow muscle that resembles an upside-down pyramid with rounded edges. It is usually about the size of a fist and weighs around 250 to 300 grams in adults. The heart is located in the center of the chest, slightly behind and to the left of the sternum, nestled between the lobes of the lungs. Due to its rich blood supply, the heart appears reddish. The pericardium, which forms the outer protective covering, has a greasy, shiny appearance. The surface of the heart may appear smooth, but may also have some grooves in which blood vessels are embedded. There are four chambers inside the heart: the right atrium and left atrium and the right and left ventricles. The walls separating these chambers contain valves that regulate the blood flow.

Fiber is considered an important part of a heart-healthy diet, primarily because of its ability to lower LDL cholesterol levels, which reduces the risk of plaque buildup in the arteries that can lead to heart disease. They can also help to keep blood sugar levels low by slowing down the digestion and absorption of carbohydrates. The intake of fiber quickly makes you feel full, which is beneficial for weight loss or maintenance, and promotes a healthy gut microbiome, which can reduce inflammation throughout the body that can promote cardiovascular disease. Omega-3 fatty acids are essential fats that also have an anti-inflammatory effect. They can also lower the triglyceride level in the blood. Elevated triglycerides are associated with an increased risk of heart disease. Omega-3 fatty acids also improve endothelial function, which helps to regulate blood pressure and prevent the formation of blood clots. In summary, both fiber and omega-3 fatty acids contribute significantly to promoting heart health through their role in cholesterol regulation, reducing inflammation, blood sugar control and overall cardiovascular function.

A heart that sits in a body cannot break because it is a flexible hollow muscle. “Breaking your heart” is merely a paraphrase for the pain you experience from negative emotions. In medicine, “broken heart syndrome” is understood to mean “stress-induced cardiomyopathy” or “Takotsubo cardiomyopathy”. This phenomenon occurs when intense emotional or physical stress leads to a temporary dysfunction of the heart that resembles the symptoms of a heart attack.

All body cells can potentially degenerate and thus develop cancer. Since most mutations occur as errors during cell division and heart cells do not divide in comparison to other body cells, with a few exceptions in the case of injuries, malignant degeneration rarely develops here. In addition, heart cells are largely shielded from harmful, carcinogenic external influences. Cancer mainly develops in cells that are exposed to changing influences and divide frequently.

Yes, artificial hearts can be implanted in cases of severe heart failure (cardiac insufficiency). Heart failure is when the heart’s pumping capacity is no longer sufficient to maintain the body’s circulation. In particularly severe cases of heart failure, a heart transplant or the insertion of an artificial heart may be considered. An artificial heart, also known as a ventricular assist device or ventricular assist device, is a small electrically powered pump that is inserted into the affected ventricle(s) and takes over their pumping function. Another therapeutic approach for heart failure is the heart patch, which is being developed by MBExC scientists. The diseased heart is strengthened by sewing on heart muscle tissue made from stem cells.

The heart is a vital organ that drives our blood circulation and provides our body with a constant supply of oxygen and nutrients. The heart pumps five to six liters of blood through the body every minute. This requires a certain size: the human heart is about the size of a fist and weighs 250 to 300 g in adults.

Both heart disease and hearing loss come in different forms and manifestations with different causes, so we cannot assume a general connection between the two conditions.
Nevertheless, there is evidence that heart health can influence hearing. Blood flow in particular plays a role here: the hair cells in our cochlea convert recorded sounds into electrical impulses. If blood flow is restricted due to heart disease, the hair cells are insufficiently supplied with oxygen. This lack of oxygen causes damage to the hair cells, which in turn leads to permanent hearing loss.
There are also certain syndromes in which both heart malformations and hearing loss can occur as symptoms, including CHARGE syndrome, Turner syndrome and trisomy 21 (Down syndrome).

Children’s hearts beat slightly faster than adult hearts, which beat an average of 70 times per minute: children’s hearts beat at around 100 beats per minute, which equates to around 130,000 heartbeats within a day (24 hours). In infants, the heart even beats up to 180,000 times within 24 hours.

There is much to suggest that the heart symbol used worldwide (❤️) is a schematic symbol for the anatomical shape of the heart. One of the oldest depictions shows this symbol in the chest of a prehistoric elephant painted on the walls of a cave in Pindal, Spain. Heart-shaped amulets were also found in the following Neolithic megalithic tombs on the Iberian Peninsula. Depictions of the heart can be found in many cultures and epochs around the world; it has been one of the main symbols of Christianity since early Christian iconography.

The tissue for the heart patch is produced from heart and connective tissue cells and takes around four weeks to mature before it is implanted.
At this point, it corresponds metabolically and structurally to early childhood heart tissue. Further maturation and biomechanical adaptation to the recipient heart takes place in the weeks following implantation.

Life without a heart is not possible, as the heart plays a crucial role in the circulatory system, which is essential for sustaining life. The heart is responsible for pumping oxygen-rich blood to all parts of the body, delivering nutrients and removing waste products as well as keeping other physiological processes going. This is vital for the survival of the body’s organs and tissues.

The sinus node or sinoatrial (SA) node is the primary pacemaker of the heart. It is activated by a special process involving pacemaker cells that generate electrical impulses. The triggered action potentials propagate through all the heart muscle cells and cause them to contract (systole). These contractions manifest themselves as heartbeat. They determine the rhythm of the heart.
In contrast to non-pacemaker cells, such as ventricular and atrial cells, which have a resting membrane potential, pacemaker cells have a pacemaker potential: After repolarization, the membrane potential of pacemaker cells begins to depolarize spontaneously and without external stimulus, without a stable resting membrane potential. The gradual depolarization leads to a threshold potential being reached, which triggers an action potential. If the membrane potential becomes too negative, a positive state is achieved again. This then flattens out again, so that the membrane potential becomes more negative again and the cycle starts all over again.

The most important task of the heart is to pump blood through the body, primarily to supply it with oxygen. The heart also fulfills the function of moving the transport of nutrients and waste products (e.g. carbon dioxide).

The heart is located approximately in the middle of the chest, between the lungs and directly behind the breastbone. This central position is particularly well suited to pumping blood to every part of the body. This allows the blood to circulate efficiently throughout the entire body. This is why the lungs are also in this place: the heart and lungs work together to bring fresh air into the human body and the stale air out again. The heart is also particularly well protected in this position: Bones such as the ribs and spine as well as the relatively large rib cage shield it well from the outside.

Basically, all hearts of a species have the same structure and are therefore similar. However, there are individual differences, for example in size, function, shape, etc. These are based on various causes, such as age, gender, health and training status.

Multinucleated cells (polynucleosis) are eukaryotic cells that share a common cytoplasm and have more than one nucleus.
Certain organisms can have a multinucleate stage in the course of their life cycle. Slime molds, for example, have a vegetative, multinucleated life stage called Plasmodium.
In humans, nuclear division without cell division can occur in giant or tumor cells due to disease, so that the cells become multinucleated.
Cardiac muscle cells (cardiomyocytes), like other muscle cells, naturally have one or two cell nuclei (binucleation). The reason for this peculiarity is not clearly understood: two cell nuclei could possibly increase metabolic activity in order to cover the high energy requirements of the (heart) muscle cells.
If another cell nucleus is introduced into a cell using a procedure such as somatic cell nuclear transfer (SCNT), this can lead to reprogramming of the recipient cell. If a somatic cell nucleus is transferred into an enucleated egg cell, this can lead to the creation of a cloned embryo.
In eukaryotic cells, which contain their own nucleus enclosed by a nuclear membrane, the introduction of an additional nucleus would probably lead to complications. In general, such an event is not a natural phenomenon in biological systems. A possible consequence could be chromosome confusion or instability. During mitosis or meiosis, the chromosomes align with the metaphase plate and divide evenly among the daughter cells. If there are two nuclei in a cell, this could lead to improper chromosome segregation and uneven distribution, resulting in genetically abnormal daughter cells. Another possible problem is the regulation of gene expression. Each nucleus would have its own set of genes, which would be activated or suppressed depending on the needs of the cell. Two nuclei could lead to contradictory gene expression programs, which could result in developmental abnormalities or even cell death.

A heart cannot repair itself, as adult heart muscle cells – unlike some other body cells, such as skin cells – do not regenerate. There are various medical approaches to repairing individual parts of the heart that have been destroyed: Stem cell-generated heart patches, for example, such as those invented in Göttingen, which are sewn onto the heart to replace the lost muscles. Work is also being carried out on methods in which parts of the heart are replaced by auxiliary medical products derived from other organisms (xenograft, e.g. from pigs). During a heart transplant, the heart is completely replaced by a donor heart. In the future, it may be possible to completely repair a heart or replace it with an artificial heart made from stem cells.

With a normal heartbeat, the sound produced is not normally audible to the person affected.
If there are irregularities in the heart rhythm or if the heart beats faster and harder than usual, e.g. during physical exertion or excitement, the blood flow through the ventricles can become turbulent. This turbulence can generate noises that can be perceived as palpitations.

During embryonic development and after birth, the heart increases in size and grows. Until birth, the human heart grows to the size of a walnut, and in adulthood it weighs around 300 grams. It was previously thought that human heart muscle cells no longer multiply after birth, but only increase in size. It is now assumed that the number of heart muscle cells continues to increase until the beginning of adulthood. The heart of adult mammals has only a very limited ability to form new heart muscle cells (cardiomyocytes), which means that the risk of cardiovascular disease increases with age.

The heart is a vital organ that pumps blood through the body to transport oxygen and nutrients to the cells. It consists of four chambers – the atria and the ventricles – which contract and relax rhythmically to pump blood around the body. The heart is controlled by electrical impulses that regulate the heartbeat.

Simple, unicellular organisms and more complex animals such as sponges, cnidarians (e.g. jellyfish) and certain worms and crustaceans do not have a heart: In these organisms, nutrients, messenger substances and waste products are transported by diffusion, i.e. distribution by independent concentration equalization or by muscle contractions of the body.
In multicellular animals, the organism is usually supplied by a blood circulation system that generates convection, i.e. a flow, driven by a pump, the heart: Circulatory systems were first found in evolution in the Bilateria, bilaterally structured animals, possibly as early as 600 million years ago.
In animals with an open circulatory system, arthropods and molluscs (snails and mussels), the hemolymph (equivalent to blood), driven by a heart, flows through the body cavity. In animals with closed circulatory systems, the heart pumps blood through vessels: veins that bring blood to the heart and arteries that carry it away.
The aquatic ancestors of terrestrial vertebrates had only a simple closed blood circulation system.
The mammalian heart differs from these in that it consists of two completely separate closed circulatory systems: the systemic circulation and the pulmonary circulation. The systemic circulation (the left half of the heart) supplies the body with blood, while the pulmonary circulation (the right half of the heart) pumps used blood into the lungs to enrich them with oxygen.
The heart also develops very early in embryonic development, which goes through similar stages to evolution: as long as the embryo consists of only a few cells, each cell can take the nutrients it needs directly from its environment. However, as soon as the cells divide and the embryo grows into a larger clump of cells, the nutrients can no longer reach all the cells without help. In addition, the cells produce waste products that have to be disposed of. To keep the cells alive, nutrients and waste products must be transported. This transport is carried out by the cardiovascular system, which is driven by the heart.

The heart is a muscle. It pumps blood through the body. The blood contains oxygen and nutrients that are distributed throughout the body:
Each half of the heart consists of two cavities, the atrium and the ventricle. Although the two halves of the heart are similar in structure, they fulfill different tasks: The left side supplies the organs with oxygen-rich blood and pumps it into the body. The right part receives deoxygenated blood from the body and transports it to the lungs. The blood is re-oxygenated in the lungs. From there it flows back into the atrium of the left side of the heart – and the cardiac cycle is closed. Heart valves ensure that the blood does not flow back in the wrong direction. The heart is excited by the sinus node: It is the physiological pacemaker of the heart.
Compared to other mammals, a pig’s heart is very similar to a human heart: It is about the same size as a human heart, i.e. approximately one to one and a half times the size of a clenched fist. The position of the heart adapts to the rib cage. As a result, the pig’s heart appears to the left compared to the human heart turned. The pig heart has heart cartilage that serves as supporting elements, which can also ossify at an advanced age.

In so-called “bioprinting”, cell conglomerates and even organ imitations are printed in 3D printers, usually on the basis of stem cells. Researchers are working on creating functional organs from these tissues. In the future, for example, a 3D-generated heart is to be created that could perhaps one day replace an inoperable heart. There is a concrete project in Stanford, USA, for example. One problem here is that complex natural organs have to be artificially reproduced in their entirety, consisting of various components: Structures and processes which, if they are known at all, are difficult to reproduce completely and equally. It must also be ensured that the materials are neither repelled nor pose any health risks.

The heart beats rhythmically to maintain blood flow in the body. It has a complex stimulus formation and conduction system that stimulates the muscles of the heart. Here are some important points about the function of the heart:

1. Sinus node: The sinus node in the right atrium takes over the pacemaker function. It builds up the tension the fastest and is the first to give the heartbeat command. If the sinus node fails, the AV node takes over this function.

2. Conduction: The excitation is transmitted to the AV node via the muscles of the atria. The AV node delays conduction so that the ventricular muscles contract only after the atrial muscles. The excitation reaches the ventricular muscles via the His bundle, which enables all the ventricular muscles to contract simultaneously.

3. Heart valves: The heart valves ensure that the blood only flows in one direction. They open and close depending on the pressure difference between the atria, ventricles and great vessels.

4. Heartbeat: In a healthy adult, the heart beats between 60 and 80 times per minute at rest. It is divided into two phases: systole (contraction phase) and diastole (resting phase). During systole, the heart muscle contracts and pumps blood into the circulatory system. During diastole, the heart muscle absorbs deoxygenated blood.

Humans cannot survive without a heartbeat. Fortunately, there are back-up systems that can take over control of the heart if the sinus node fails or conduction is disturbed. The heart is an amazing organ that keeps us alive!

A defibrillator is a medical device that can be used to terminate cardiac arrhythmias such as ventricular fibrillation, ventricular flutter, ventricular tachycardia, atrial fibrillation and atrial flutter using targeted electric shocks.

External defibrillator (AED): An automatic external defibrillator (AED) is intended for first aid in an emergency and is designed so that even laypersons can use it without difficulty. These devices can often be found in public facilities or in busy places. An AED has electrodes that are placed on the affected person’s chest. Current pulses are delivered via these electrodes to normalize the disturbed heart rhythm. The current pulses of defibrillators differ slightly from manufacturer to manufacturer. Average values apply: Voltages between 1,000 and 2,000 volts (V), initial currents of around 20 to 30 amperes (A), energy of 150 to 360 joules (J) for adults.

Implantable cardioverter defibrillator (ICD): An ICD is a device only a few centimeters in size that is surgically implanted in the body below the collarbone. It monitors the heartbeat and sends electrical impulses to the heart via electrodes in the event of cardiac arrhythmia in order to restore the normal rhythm. The exact current strength is delivered via the electrodes and is crucial for the successful treatment of cardiac arrhythmias.

If the heart does not function properly, this is known as heart failure or cardiac insufficiency.
The heart can then no longer pump enough blood through the body, which can lead to various problems, e.g:

1. lack of oxygen and nutrients: the organs do not get enough oxygen and nutrients, which can impair their function.
2. fluid accumulation: Blood can build up, especially in the lungs or abdomen, which can be life-threatening.
3. exhaustion and weakness: those affected often feel tired and less resilient.
4. breathing problems: Fluid accumulation in the lungs can cause shortness of breath.

A head transplant is not possible in vertebrates (including humans).

The brain is not a muscle.
Like many other organs, it consists mainly of proteins and fatty components (lipids).
It feels similar to a pudding.
It consists of two types of tissue: the “gray matter” and the “white matter”.
The gray matter, which is about two millimeters thick, forms the surface of the brain.
Underneath it lies the “white” matter, which makes up the largest part of the brain.

In the course of human evolution, the size of the brain has increased considerably: From early hominids to modern Homo sapiens, its size has tripled, presumably as a result of changing environmental conditions to which new strategies for adaptation had to be devised.
Certain areas of the brain are particularly associated with higher cognitive functions.
The prefrontal cortex plays a crucial role in decision-making, planning and social behavior.
As the size of the brain increases, so does the complexity of the structures of these regions and their connections to other parts of the brain.
While these larger brains have brought significant benefits in terms of cognitive abilities, they have also come at a price: the larger the brain, the more energy is required.
Today, a brain accounts for around 20 % of a person’s total energy consumption, although it only accounts for around 2 % of body weight.
In addition, larger brains make childbirth more difficult, which can lead to complications.
Although larger brains can generally process more information than smaller ones, the correlation with cognitive abilities goes beyond volume alone.
The density and connectivity of the neurons are the key factors.

The human brain is capable of remarkable adaptation.
This adaptability can manifest itself in different ways, particularly in people who have suffered significant neurological challenges or injuries.
“Neuroplasticity” refers to the brain’s ability to reorganize itself throughout life by forming new neural connections.
This allows the brain to compensate for injuries and adapt to new situations or changes in the environment.
For example, after a stroke or traumatic brain injury, areas of the brain that are still functional can take over the tasks of the damaged regions.
This adaptability is not the same for all people; some brains have greater neuroplasticity than others due to genetic factors, age, health and previous experiences.
The extent to which a person can compensate for deficits also depends largely on the location of the damage.
The brain is particularly plastic in the early years of life.
If damage occurs here, impressive compensations can occur, as in the example of the patient with the “extremely repressed and marginalized brain” described in the publication by Feuillet L, et al.
Brain of a white-collar worker.
Lancet.
2007 Jul 21;370(9583):262.

Many parts of the brain are already being used at any one time, even if not constantly and simultaneously, so that brain capacity is never fully utilized. Each region of the brain is specialized in different functions, e.g. motor control, sensory perception, language processing and higher cognitive functions such as thinking and decision-making, and there are also specializations within these areas. Even during simple tasks or at rest, several regions of the brain are already active. Although we cannot “activate” all neurons at the same time, we can improve our cognitive abilities through practice, learning and experience, which is known as “neuroplasticity”. Engaging in new activities, learning new skills or practicing mindfulness, for example, can lead to structural changes in the brain, while unused areas atrophy. The formation of new nerves from stem cells, known as “adult neurogenesis”, is possible in certain regions of the brain and could also be promoted by mental and physical activity. As with other peak performances, cognitive abilities can also be increased enormously through training and education, but there are biological limits that are determined by genetics, age, state of health and environmental factors. Ongoing research into methods to improve cognitive abilities – including pharmacological interventions and technological aids – is looking for ways to maximize the potential they offer. In future, technologies such as brain-computer interfaces could help to utilize previously unused abilities or further improve existing ones.

The brain is about the size of two clenched fists and weighs around 1.5 kilograms. Brain tissue contains around 100 billion nerve cells and around one trillion supporting cells that stabilize the tissue.

Basically, the brains of humans and mice – like those of all mammals – have the same structure. The human cerebrum is much more developed, but the olfactory bulb is smaller than that of the mouse.

From the physical need for energy, it is understandable that the body craves sugar and with chocolate this is reinforced by the mood-enhancing components of cocoa. The very sight of chocolate releases the neurotransmitter dopamine in the brain in anticipation of the learned pleasure associated with it, which increases the motivation to eat the chocolate. A low blood sugar level can also lead to increased cravings for sugary foods, as the body then searches particularly urgently for quick sources of energy. This biological urge can overwhelm rational thought processes and give you a feeling of “mental suspension”. There are various strategies to make desired but difficult behavior easier to implement. In the case of chocolate, it would probably make sense to avoid the trigger of the eating stimulus as much as possible, i.e. not to surround yourself with chocolate, i.e. not to have chocolate lying open on the table or not to buy chocolate in the first place. In addition, you should make a conscious decision to eat or go without, limit individual portions from the outset and then enjoy them according to plan. It can also be helpful to deassociate the consumption of chocolate from certain actions if you want to limit it, i.e. not always sweetening a negative situation with chocolate, but alternating between other compensations, as otherwise the body is easily conditioned to chocolate when consolation is needed. Cravings, in turn, can be prevented by eating regular (healthy) meals that prevent extreme hunger pangs and reduce the likelihood of impulsive chocolate binges.

In terms of its consistency, a brain is very similar to a stiff jelly. In any case, it is softer than a hard-boiled egg. The brain is well protected by the bones of the skull and therefore does not need its own strong support structure. Ordinary images of a brain usually show fixed organs, i.e. specimens hardened by chemicals, so it is easy to get the impression that the brain is rather solid.

The brain of an adult has an average volume of approx. 1.2 liters and weighs around 1-1.5 kg. In fact, the brain gets smaller with age, which is a normal part of the ageing process and does not necessarily lead to a loss of cognitive abilities. Much more important than the size or weight of the brain, however, are the connections between the approximately 100 billion nerve cells. Neurodegenerative diseases such as Alzheimer’s are characterized by the death of nerve cells in certain areas of the brain. This leads to the breakdown of brain substance, also known as brain atrophy. The progressive breakdown of brain matter in Alzheimer’s disease can be visualized using imaging techniques such as MRI. Strokes or traumatic brain injuries can also lead to brain atrophy. This leads to the acute, irreversible death of nerve cells in the brain. Studies also show that patients with severe depression have a smaller hippocampus than healthy people. The hippocampus plays an important role in learning and memory processes, among other things. However, it is unclear whether the reduced size of the hippocampus is a consequence of depression or whether people with a small hippocampus are more susceptible to the disease.

We speak of brain death when there is an irreversible loss of function of the entire human brain, i.e. the cerebrum, cerebellum and brain stem. The cause of brain death is acute severe damage to the brain, e.g. due to a traumatic brain injury or a stroke. In various neurodegenerative diseases such as Alzheimer’s or Parkinson’s, nerve cells in the brain die off, leading to a loss of cognitive and motor skills. Strokes can also cause brain tissue to die, which can lead to loss of function.

The human brain is a complex organ that controls all bodily functions. It weighs around one to one and a half kilograms and consists of around 100 billion neurons and an equally large number of other cells, mainly supporting cells that stabilize the tissue. It is divided into three main parts (cerebrum, brain stem and cerebellum) and the diencephalon with the thalamus, hypothalamus and pituitary gland.
The cerebrum, the largest part, is divided into two hemispheres, each with four lobes – the frontal, parietal, temporal and occipital lobes – and is responsible for functions such as thinking, reasoning and sensory processing.
The outer layer of the cerebrum is the cerebral cortex, which consists of layers of gray matter and is 2 to 4 millimeters thick. Below the cortex lies the white matter of the brain. The largest part of the cerebral cortex is the neocortex, which consists of six neuronal layers, the rest is the allocortex with three or four layers. The cerebral cortex is divided into around fifty functional areas known as Brodmann areas.
The second largest part of the brain is the cerebellum, which is located under the back of the cerebrum and plays an important role in the coordination of movement and balance. The third largest part is the diencephalon, which is located in the core of the brain and contains structures such as the thalamus and the hypothalamus, which serve as relay stations for incoming nerve impulses and control the release of hormones from nearby glands such as the pituitary gland.
The brain stem connects the cerebrum to the spinal cord and controls reflexes and basic life functions such as heart rate, breathing, blood pressure, sleep and wakefulness and regulates the connections between the cerebrum, cerebellum and spinal cord.
The human brain is protected by a hard bone skull and three tough, fluid-filled membranes known as meninges. Another protective feature is the blood-brain barrier, which prevents the penetration of harmful substances and at the same time allows the passage of vital nutrients. Despite these protective mechanisms, injuries or malfunctions can occur, which can lead to neurological disorders (stroke, epilepsy), dementia (Alzheimer’s) or mental illnesses (anxiety disorders).

The brain processes visual information in a complex sequence of steps: When light enters the eye, it is focused by the lens and projected onto the retina at the back of the eye. The retina contains photoreceptor cells (rods and cones) that convert light into electrical signals. These signals are then transmitted via the optic nerve to the visual cortex at the back of the brain. These signals are processed and interpreted in the visual cortex.

Auditory information is processed in a similar sequence of steps: Sound waves are picked up by the outer ear and travel through the ear canal to the eardrum. The vibration of the eardrum is transmitted to the cochlea in the inner ear via three tiny bones (hammer, anvil and stirrup) in the middle ear. In the cochlea, hair cells convert these vibrations into electrical signals, which are transmitted via the auditory nerve to the auditory cortex in the brain. The auditory cortex processes and interprets these signals.
The brain integrates information from multiple senses to create a coherent representation of our environment and experience the world in a comprehensive way.

While organ transplants have made significant progress over the years, the complexity of the brain and its connection to the body present significant practical obstacles to transplantation. In addition, there are understandably considerable ethical concerns. It is therefore unlikely that brain transplants will become a reality in the foreseeable future, if at all.

Some brain damage is irreversible, while the body can repair other damage, especially minor damage, through self-healing: Damaged nerve cells can reorganize themselves and compensate for lost functions. This is called neuroplasticity.
However, this ability is limited. Scientists are therefore researching how to replace parts of the brain. This is not yet possible in comprehensive medical treatment.
Stimulation with magnetic fields (transcranial magnetic stimulation, TMS) is intended to activate or inhibit selected areas, thereby restoring the damaged brain to a state ready for learning.
One of the aims of stem cell research is to replace individual diseased and aged cells with healthy nerve cells produced from stem cells. Today, for example, skin cells can be reprogrammed into stem cells. These stem cells multiply relatively easily and can then develop into different cell types, including nerve cells, in cell culture with the help of growth factors and certain nutrient fluids. These nerve cells could then be inserted into the patient to compensate for any damage. This treatment goal is still being researched under high pressure and has so far only been realized in clinical trials.
However, each neuron has several, sometimes thousands of connections to other neurons that require lengthy maturation processes, which is why it is difficult to replace destroyed brain tissue with stem cells. New connections only develop if the lost skills are practiced again and again, and this takes time and sufficient repetition.
In parallel, research is being carried out into whether the body’s own glial cells, which have been destroyed as a result of acute traumatic brain injuries, can be reprogrammed into neurons.
Others are researching artificial neurons, electronic devices that resemble biological neurons in their functions and that could be implanted in the body in the future, where they could establish contact with real neurons and support them in their communication.
The company “neuralink”, founded by Elon Musk, is developing a battery-powered brain-computer interface that can be implanted in the brain and is designed to record the neuronal activity of around 1,000 nerves and transmit it to external computers in order to transmit the thoughts that these devices are then supposed to control. At the beginning of this year, the first patient was fitted with this implant as part of the PRIME study (Precise Robotically Implanted Brain-Computer Interface). He is able to move a computer mouse locally on the screen with his thoughts.
Other companies are also working on neuroprostheses that transmit brain impulses to orthoses, which are then intended to move paralyzed limbs, for example. The passive movement could create a feedback loop back to the brain, which should help it to reorganize itself and relearn the coordination of the paralyzed body part.
In Göttingen, the Else Kröner-Fresenius Center for Optogenetic Therapies is also conducting research on the topic of brain-computer interfaces.

Primitive and simple animal organisms, such as jellyfish, have no brain. However, they have simple nerve networks that run through their bodies. The human brain in all its complexity is ultimately based on these electrically and chemically excitable nerve cells (neurons). More complex creatures have an additional instance that brings together information from different parts of the body and controls a reaction: the brain.
This is found in worms, for example: Animals that are not circular, like jellyfish, but aligned longitudinally, i.e. where there is a front and a back. At the front, the neurons condense to form a control center: the brain.
The number of neurons present in the brain and thus the number of possible connections determine the performance of the brain and thus the complexity of behavior. The folded structure of the brain makes it possible to accommodate as many nerves as possible.
Human brain volume has increased dramatically over the course of evolution – it has tripled compared to our ancestors around four million years ago, the australopithecines, the first upright walking pre-humans. It has experienced a particular increase in size since the early hominids, around two million years ago. A large part of brain growth takes place after birth. This makes the brain much more dynamic and better able to react to changes in the environment. The brain underwent a further developmental leap with the appearance of the genus Homo sapiens sapiens, around 100,000 years ago: The brain changed from an elongated to today’s round skull shape, presumably accompanied by the further development of complex thought processes.

The brain is still too complex to be captured in its entirety, reconstructed and uploaded to a cloud. It is not known what functions a microchip would have to have in order to completely replace a nerve fiber or even all nerve fibers and their connections to each other.
It is only theoretically possible to imagine recreating all neurons and their functions in a computer. However, this would not correspond to an equivalent copy of the human being, not to a consciously thinking and feeling human being. Because to be “oneself”, to feel consciousness as a human being, requires more than just the totality of data and neurons at a certain point in time. The brain needs the rest of the person around it and interaction with the environment in order to develop an awareness and sense of self. Detached from a person, isolated in a computer, without incoming stimuli, it would not develop in the same way and would therefore only represent a snapshot, like a blueprint, of the sum of parts necessary for complex thoughts and sensations of consciousness. Nevertheless, it is theoretically conceivable that these processes could be replicated outside the body or temporarily outsourced.

The blood-brain barrier is the border between the blood and the central nervous system. Only certain substances can pass through the cells on the outside of the vessel wall into the brain. This protects the brain from harmful substances, pathogens and toxins. However, this protective function of the brain also makes it difficult to treat a large number of neurological diseases with medication, as many active substances cannot pass the blood-brain barrier. Diabetes can lead to changes that impair the barrier effect and the transport functions of the blood-brain barrier.

The human brain is probably the most complicated organ that nature has ever produced: 100 billion nerve cells and many times that number of contact points give it capabilities that no supercomputer can match.
The brain is about the size of two clenched fists and weighs around 1.5 kilograms. Brain tissue contains around 100 billion nerve cells and around one trillion supporting cells that stabilize the tissue. The folds of the brain make it possible to accommodate many nerve cells in a relatively small space. The areas of the brain are divided into the cerebrum, cerebellum, brain stem and diencephalon. They work together, but also have different specializations, such as sight, smell, speech, movement, etc. The cerebrum consists of a right and a left hemisphere. Both are connected by a thick bundle of nerve fibers, the beam. The right hemisphere of the brain controls the left side of the body, while the left hemisphere is responsible for the right side.
The brain processes sensory impressions and information from the body and sends messages back to all areas of the body. New, even unfamiliar sensory impressions are compared and evaluated with experiences that are stored as knowledge in order to elicit the most appropriate behavioral responses. Like a map that navigates you through geographical spaces, all information in the brain is stored in spatial patterns in grid cells – in a kind of coordinate system of thoughts.
Some thought processes take place consciously, others unconsciously. Individual thinking processes do not yet constitute conscious thinking: a conscious thought only arises through the interaction of various biological processes: the brain does not think, the person as a whole thinks. Stable cognitive control is the exception: most thought processes take place unconsciously.
Even in old age, the brain is constantly being remodeled: It can learn throughout its life. The strength with which signals are transmitted between nerve cells is constantly adjusted: What is useful and is carried out more often is strengthened, what is not used is weakened and forgotten.

Indeed, the ultimate clinical symptoms in Alzheimer’s disease and in some other types of dementia arise due to excessive cell death (note that there are some types of dementia that are not associated with cell death).
While there is intense research on the idea of re-introducing cells in the brain to compensate for those that die, we are still not at a point where we can do this. Hopefully, in the future, we will be able to explore different strategies to achieve this goal.

Animals are just as susceptible to illness as humans.
Without medical care, they even fall ill quite often.
To survive in the wild, animals need to be very fit.
Even minor restrictions can cause them to suffer from a lack of food or fall victim to predators.
However, as sick animals often do not grow old in the wild and the mortality rate for young animals is very high, diseases typical of old age in humans do not affect animals as much.

Your reasoning is correct, it is just the other way round: skin cancer does not occur despite, but precisely because of the formation of new cells. Tumors usually form as a result of mutations, i.e. errors in cell division. Organs whose cells divide less frequently (e.g. the heart and brain) are less likely to develop cancer. When cancer occurs in these organs, it usually affects the surrounding supporting tissue (e.g. the glial cells in the brain, but even these divide less than e.g. epithelial tissue). Most cancers that affect these organs are secondary or metastatic and not primary. Cancer mainly develops in cells that are exposed to changing influences (such as skin or intestinal cells) and that divide frequently, although in principle all body cells can degenerate and thus develop cancer. Cancer is therefore basically a disease characterized by uncontrolled cell division: in cancer, these regulatory mechanisms fail, leading to excessive cell proliferation. Normally, damaged or superfluous cells undergo apoptosis (programmed cell death). Cancer cells often bypass this process, allowing them to survive longer than they should. Could stopping cell division defeat cancer? While it may seem logical that interrupting cell division could prevent the progression or further development of cancer, the reality is much more complex: not all cell division is harmful; normal tissue must constantly renew itself through regulated cell division. If all cell divisions were stopped indiscriminately, this would also affect healthy tissue, which is dependent on cell division in most areas. Many chemotherapeutic agents work by interrupting the mitotic process specifically in rapidly dividing cancer cells. However, the interruption of cell division can lead to considerable side effects, as many normal tissues are also dependent on rapid turnover (e.g. hair follicles, gastrointestinal mucosa). Cancer cells can also develop resistance to treatments designed to stop their proliferation. Therefore, various strategies such as immunotherapy and gene therapy are being researched to effectively combat cancer without completely disrupting normal cell function.

When explaining epilepsy to a child, it is important to use simple language. Analogies make it easier for children to understand what epilepsy is and how it affects those affected. First of all, you should explain to the child what the brain is and what role it plays in the body, that it works with electrical signals that can be disturbed in epilepsy, which can manifest itself in the form of a seizure. Then you could address the triggers to end up with a treatment option. A possible child-friendly explanation would be the following: “Our brain is like a control center for our body. It helps us to think, move, feel and even breathe. It sends messages through our nerves to tell our body what to do. The brain uses electrical signals to talk to different parts of our body. These signals help us do everything from moving our fingers to remembering things. Sometimes there is a problem with these electrical signals in the brain. When this happens, it can result in an epileptic seizure. A seizure is like a big storm in the brain where all the signals get mixed up for a while. Some people shake or fall over during a seizure, others just stare blankly in front of them for a moment or seem confused. Some things can cause seizures to occur more frequently, such as being very tired or stressed. But there are medications and treatments that help many people with epilepsy to feel better and have fewer seizures. If someone has epilepsy, it doesn’t mean he is sick all the time; he just sometimes needs a bit more attention and protection to prevent falls, for example.”

Find out more about Alzheimer’s disease, its stages and symptoms.
This will enable you to understand your grandmother better and react accordingly.
Use simple language when communicating with your grandmother: speak clearly and in short sentences.
Avoid complex questions that could confuse her.
Be patient: give her time to respond and don’t interrupt or correct her too much to avoid causing unnecessary frustration.
Create a safe environment for her: Eliminate hazards such as tripping hazards and sharp objects.
Consider additional safety measures such as grab rails and non-slip mats.
Label doors, drawers and rooms to make it easier for her to find her way around.
Maintain a structured, fixed daily routine.
Encourage her to take up hobbies that she enjoys and that she may remember from before, provided she is still able to do so.
Physical and mental activity can slow down the mental decline process.
If possible, let her do light physical activities such as walks or stretching exercises and let her listen to her favorite music or sing together.
Offer nutritious, healthy meals that are easy to eat.
Make sure she drinks plenty of fluids throughout the day.
If possible, arrange visits from family members or friends so that she can engage socially.
You could possibly join a support group and consider professional (nursing) help.

Knowledge about diseases arose and still arises from repeated observations of symptoms, patterns derived from them and traditional experiences and the logical linking of the two to form theories. Due to the small population and small, relatively isolated hunting and gathering groups of the Stone Age, it can be assumed that they were less affected by infectious diseases than we are today. It was only through sedentarization, the increase in group size and the close coexistence with domestic animals and vermin in food storage and agricultural waste that many of the infectious diseases still prevalent today developed and spread. If people fell ill among the hunting and gathering ancestors, it can be assumed that these illnesses were attributed to spiritual causes: In many shamanic cultures, for example, it is or was assumed that illnesses are caused by lost souls (a person had several souls) – in the event of illness, a shaman must go on a trance journey into the spirit realm to retrieve the lost souls and thereby heal the sick person. Others saw or see the evil eye, curses, enemies, sorcerers, witches or demons at work in illnesses. In the European Middle Ages, illness was seen as a punishment sent by God for sins committed. In line with Galen’s humoral pathology, based on the teachings of the Greek physician Hippocrates of Kos, who lived in the 5th century BC., the aim was to restore the imbalance of the “humors” in the event of illness. Bloodletting was performed for many symptoms. The increasing globalization and mobility of people in conjunction with steadily rising population numbers led to a further spread of diseases. As the Middle Ages drew to a close, new insights into physiology, pathology and anatomy found their way into medicine as the influence of the church declined and the nature-based ideas of the Enlightenment emerged. Girolamo Fracastoro (16th century) assumed that diseases were transmitted by tiny animals or germs through contact or through the air. Descartes (17th century) traced all life processes back to physical-mechanistic principles. But it was not until the 19th cent. Rudolf Virchow recognized that diseases are based on cellular disorders and Louis Pasteur proved that all of this is based on biochemical processes involving microorganisms. Around the same time, Robert Koch discovered bacteria: tiny organisms and the cause of infectious diseases. At that time, infectious diseases such as tuberculosis, cholera, diphtheria and wound infections were the main cause of death worldwide.

Parkinson’s disease is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, an important area of the brain involved in the control of movement.
The primary treatment for Parkinson’s is the administration of dopamine or dopamine precursors, such as levodopa, to relieve motor symptoms.
However, many patients respond less and less to these therapies over time.
This is mainly due to the fact that as the disease progresses, dopaminergic neurons are often lost, resulting in less dopamine being produced.
It is also due to the reaction of the dopamine receptors, which become less sensitive due to long-term exposure to high dopamine levels (downregulation).
Parkinson’s disease not only affects dopamine, but also other neurotransmitter systems (e.g. serotonin, noradrenaline).
As the disease progresses and dopaminergic treatment becomes less effective, other neurotransmitter imbalances can in turn contribute to a worsening of symptoms.

People with heart failure can suffer from cognitive deficits and an increased risk of Alzheimer’s disease. A number of factors play an important role here. Firstly, heart failure can lead to the brain no longer being supplied with sufficient oxygen and nutrients in the long term. In principle, this also applies to other organs, but the brain requires around 20% of the energy produced. Unlike most other cells in our body, brain cells do not divide and are therefore irrevocably lost when they die. The brain is therefore particularly susceptible to a prolonged undersupply of energy and nutrients. André Fischer, MBExC member and spokesperson for the Göttingen site of the German Center for Neurodegenerative Diseases (DZNE), together with MBExC members Gerd Hasenfuß and Karl Toischer from the University Medical Center Göttingen, are investigating exactly how nerve cells are damaged by cardiac insufficiency. Using model systems, they were able to show that chronic heart failure alters the activity of certain genes in nerve cells, which is mediated by so-called epigenetic processes. Epigenetics, for example, refers to certain chemical changes in histones, proteins that form the support structure for DNA and thus regulate gene activity. By using drugs that influence these histones, the researchers were able to alleviate the cognitive deficits with equally weak cardiac performance, a starting point for a possible therapy.

Amyotrophic lateral sclerosis (ALS) is an incurable, severe disease of the nervous system. Motor nerve cells (motor neurons) in particular are increasingly damaged – i.e. nerve cells that are responsible for controlling and regulating muscles and movements. ALS patients exhibit abnormal activation patterns in the motor cortex during voluntary movements. This dysfunction can lead to muscle weakness, spasticity and eventually paralysis. The motor symptoms are accompanied by cognitive impairments ranging from mild executive disorders to frontotemporal dementia (FTD). Despite progressive neurodegeneration, some ALS patients show compensatory mechanisms in which additional brain regions are recruited to maintain motor function. These compensatory changes may reflect adaptive plasticity in response to neuronal loss. In most ALS patients, certain genes are mutated. Mutations in the SOD1 gene, for example, are very common and can lead to the corresponding SOD1 protein clumping together in the cell and thus disrupting the function of the nerve cells. There are therefore recently approved drugs that aim to reduce the level of the mutated SOD1 protein. There are other genes that are mutated not only in ALS, but also in patients with FTD. This means that ALS and FTD show genetic and therefore often clinical overlaps, which is why cognitive disorders often occur in ALS patients, as already mentioned.

The development of mental illness depends on many factors. Genetic predispositions probably play a role in the development of mental illnesses. However, environmental factors and life experiences also have a considerable influence. It is difficult to determine an exact percentage of how much of a mental illness is genetic and how much is influenced by daily exercise. This certainly varies from person to person.

It is difficult to choose one disease as the “worst”. There are diseases that are fatal within a very short time, such as severe malformations in unborn babies, who are sometimes not even born alive or die shortly after birth. An illness would probably also be described as “serious” if it is incurable, i.e. if it leads to premature death and the person affected and those around have to suffer greatly as a result. However, many diseases are comparatively mild and can be cured. Fortunately, serious illnesses are rare and usually only affect a few people. The most common causes of death today are cardiovascular diseases.

Frontotemporal dementia is a rare form of dementia in which nerve cells in the frontal and temporal lobes of the brain die off. As the exact causes of frontotemporal dementia are currently largely unknown, there is currently no cure for this form of dementia. From the time of diagnosis, the average life expectancy of patients is eight years. Researchers, e.g. at the German Center for Neurodegenerative Diseases (DZNE), are working to better understand the causes and progression of frontotemporal dementia and thus create the conditions for efficient therapies.

According to a review of the literature and consultation with neurologists, there is no known direct link between IIH (idiopathic intracranial hypertension) and the heart. Increased intracranial pressure (for example, as a result of a cerebral haemorrhage) can lead to an increase in blood pressure and an occasional decrease in heart rate. This is known as the “Cushing’s reflex”. However, in IIH, as far as we know, the pressures are usually much lower than those that can trigger a Cushing’s reflex. It is important to remember that people with IIH are often overweight, which is a cardiovascular risk factor.

Yes, indeed, Prof. Tiago Outeiro from the MBExC has been working on various fronts with Prof. Bas Bloem. Thank you for your comment!

mRNA can be used to vaccinate against diseases.
mRNA vaccines have proven to be effective strategies for the prophylaxis and the treatment of diseases in terms of efficacy, safety and scalability. They are used to combat infectious diseases such as COVID-19, influenza, Zika virus and rabies. In the field of oncology, mRNA vaccines are also promising as immunotherapeutic agents against various types of cancer.

We are living exciting times in the field of Alzheimer’s and Parkinson’s disease, with several ongoing and promising clinical trials. After a few decades of
disappointment, we now have some hints that we might be on the right track,
with some trials showing some positive effects, albeit still not as strong as we would like. As scientists, we cannot put a timeline for when we will be able to solve the mysteries we still face, but we can be hopeful and trust the large community working on the topic. I am confident that, in the coming years, we will continue to have exciting results and a better understanding on the mechanisms involved in these devastating diseases.

Diseases can be inherited in different ways, depending on the type of disease. Some diseases are caused by mutations (changes in the DNA caused by spontaneous errors or environmental influences) in individual genes. They are inherited either autosomal (outside the sex chromosomes) dominant, autosomal recessive or X-linked. Autosomal recessive means that the disease only occurs if a pathogenic change is found in one of the two chromosomes. In the case of dominant inheritance, one altered chromosome is sufficient. In diseases caused by the mutation of an X-linked gene, men are usually affected, while women are not or only slightly affected, as the second normal allele completely or largely compensates for the genetic defect.
Other diseases can be caused by a combination of genetic and environmental factors. There are also complex diseases in which several genes and environmental factors play a role. The research field of epigenetics deals with the influence of these environmental factors.

Yes, we believe that AI will significantly enrich science. In fact, AI is already being used in many MBExC projects – for example, to automatically identify cells or organelles in biological imaging, or to optimise technologies such as the optical cochlear implant. However, AI methods such as deep learning remain one data analysis technique among others. While they can solve problems that other approaches cannot, they are not always the right tool. They also carry risks because they are often less interpretable than traditional data analysis techniques. This makes thorough validation and careful interpretation of AI-generated results particularly important.

Deep learning is already widely used in the heart and brain research of the Excellence Cluster, for example to automatically recognise biological structures such as cells or organelles in large amounts of image data, or to optimise technologies such as the optical cochlear implant. However, this is a data analysis tool that cannot be used for every scientific question. Biological research questions often require other, sometimes simpler or more specific methods of analysis, meaning that the use of deep learning is not appropriate or necessary in these cases.

Touching the patient during shock delivery can pose serious risks to the human body. This depends on the current strength and the current path through the body. Possible effects are e.g: Nerve and tissue damage, Cardiac arrhythmia if part of the current flows through the heart, Muscle cramps and uncontrollable muscle contractions and burns.

Conventional light microscopes have the diffraction limit of light as their resolution limit: it is not possible to measure below around 200 nm. However, this limit has been overcome by the invention of fluorescence light microscopy, such as the STED microscope by Göttingen Nobel Prize winner and MBExC member Stefan Hell. These microscopes achieve a resolution of less than 2 nm.

In this question, it is important to distinguish between a pacemaker and a defibrillator.
A defibrillator usually only has one probe, which is located in the right ventricle and can stop life-threatening cardiac arrhythmias.
If the heart’s natural pacemaker (sinus node) or the AV node no longer functions properly, a pacemaker may be required.
This has a second probe that is placed in the right atrium of the heart and takes over the task of keeping the heart beating at a steady rhythm if the heartbeat becomes too slow.
If a patient already has a defibrillator and also develops problems with the sinus node or the AV node, the defibrillator with a second probe can also take over the pacemaker function.

A defibrillator basically consists of a unit and electrodes or probes.
These electrodes in the heart register the ECG and transmit it to the unit.
The defibrillator can detect cardiac arrhythmia and stop it, for example, by delivering a shock (defibrillation).

In early 1980, an automatic defibrillator was implanted at Johns Hopkins Hospital in Baltimore.
(Mower M (1991)
Building the AICD with Michel Mirowski.
Pacing Clin Electrophysiol 14:928-934.) The first author of the corresponding publication was the cardiologist Dr. Michel Mirowski, the inventor of the implantable defibrillator.
It had taken over 10 years to realize the project, as he first had to convince some critics (Kastor JA (1989) Michel Mirowski and the automatic implantable defibrillator.
Am J Cardiol 63:1121-1126).

Yes, the dying process can be prolonged by a defibrillator. However, it cannot stop the dying process, as the mechanical cardiac output is independent of the heart’s electrical activity. This means that if the heart muscle is restricted in its pumping function for various reasons, even the defibrillator cannot “undo” this. The dying process can be prolonged because the defibrillator’s shock function (= current output) can stop cardiac arrhythmia, which can lead to death. For this reason, defibrillators can be deactivated for patients after careful consideration. This is the case, for example, for patients in palliative situations, i.e. terminally ill people at the end of their lives.

Hearing loss and deafness do have an impact on the structure of the brain: at worst, they can lead to impaired cognitive performance.
Conversely, the restoration of hearing through hearing aids or cochlear implants can have a positive effect on the structure of the brain.

The cochlear implant is inserted into the inner ear, which is firmly embedded in the skull bone. The electrodes are located in the ossified inner ear. There is no contact with the brain. The receiver coil is located between the skull and the scalp behind or above the ear. The transmitter coil is magnetically attached to the scalp from the outside, and the microphone and sound processor are hung behind the auricle.

The light-sensitive proteins (rhodopsins originally obtained from algae) are injected into the body using adeno-associated viruses (AAV), which are harmless to humans and are used as vectors (means of transportation or “gene ferry”).
Since this treatment does not change the genome of the cells and since the stability of the introduced DNA is not certain, the treatment may actually have to be repeated.
However, animal experiments suggest that the desired effect lasts for at least several years.

Hearing loss caused in the ear canal or middle ear can often be treated successfully. Sensorineural hearing loss is caused by damage to the inner ear (cochlea) or the nerve pathways that lead from the inner ear to the brain. It is caused by ageing, loud noises, certain medications (ototoxic drugs) or genetic factors. Damaged hair cells in the cochlea cannot regenerate in humans. Therefore, there is no cure that restores normal hearing, but treatments such as hearing aids and cochlear implants can significantly improve hearing function. At the University Medical Center Göttingen, in the working group of Tobias Moser, spokesperson of the MBExC Cluster of Excellence, gene therapy methods are being developed that aim at a causal, regenerative treatment of hearing loss/deafness in Otoferlin-induced hearing loss. These methods are currently undergoing clinical trials.

Some people are born deaf due to genetic defects. Early-onset hearing loss is also thought to be predominantly genetic. Conductive hearing loss can be the result of a blocked ear, an ear infection or other damage to the outer or middle ear. In later life, hearing loss is usually caused by natural ageing processes or noise, (frequent) infections or ototoxic medication. These damage the inner ear (the cochlea) or the auditory nerve pathways leading to the brain. Hearing loss can also occur suddenly, sometimes the causes are unknown, or it is caused by infections, circulatory problems or head injuries.

An auditory brainstem implant (Abi) is a technical hearing prosthesis that is used when the auditory nerve is damaged or non-existent. The auditory nucleus (cochlear nucleus) in the brain stem is electrically stimulated. However, the hearing impression achieved does not come close to that of the more commonly used cochlear implants. The ABI is not used in adolescents under the age of twelve, as their brain stem is still growing. An optical brainstem implant does not (yet) exist. The optical cochlear implant is also still being researched. As far as the sensation of hearing is concerned: even with ordinary hearing aids, the initial sensory impression is often unfamiliar and irritating. However, this first strange impression is often temporary when worn frequently or permanently and is soon replaced by habituation. This is due to the fact that the human brain is extremely good at processing altered sensory perceptions and extracting as much information as possible from them. So you quickly get used to it and then perceive the sensory impressions as normal. Compared to a cochlear implant, however, speech recognition with a brainstem implant is much poorer and hardly possible without additional lip-reading.

The term “tinny” is mainly used by cochlear implant users who compare the experience of natural hearing with a healthy or only slightly hard of hearing ear with the sound of the cochlear implant.
Particularly in the first few days or weeks, the sound impression is different and sometimes unpleasant.
Over time, however, most people get used to it and then find the sound normal.
The question of how long the affected person was previously deaf plays a major role.
This suggests that the processing of hearing in the brain was “unlearned” during deafness.
Children who use a cochlear implant do not usually describe it this way.
Most of them have no comparison to natural hearing because they are deaf on both sides.
The speech of hearing impaired people with or without a cochlear implant does not sound tinny to people with normal hearing.
People with profound hearing loss and deaf people often speak relatively loudly, somewhat “lumpy” and with unclear consonants, but the pitch and intonation of speech are not significantly altered.
The change in speech is primarily dependent on how well the affected person hears themselves and thus receives feedback on how their own speech sounds.
Children who were fitted with a cochlear implant at an early age usually speak so normally that the difference is barely noticeable.

The first microscopes were created in Europe in the 17th century. The Dutchman Cornelis Drebbel was one of the first to build and sell microscopes. His compatriot Zacharias Janssen also experimented with lenses and sold microscopes and telescopes. The famous brass microscopes with a single glass lens by Antoni van Leeuwenhoek (1632-1723) from Delft achieved a much higher resolution than all previous instruments, with a magnification of 50 to 200 times. Leeuwenhoek used it to examine details from nature (hair, saliva, pond water, etc.). Microbiological research began with him. Other early researchers in the Netherlands and Italy also experimented with lenses. The first theories on optics, telescopes and microscopes were put forward by Galileo Galilei, Johannes Keppler and Robert Hooke. Ernst Abbe, Carl Zeiss and Otto Schott founded the glass laboratory in Jena in the mid-19th century. the industrial production of microscopes and optical lenses.

A functioning auditory nerve is required for both the “normal”, i.e. electrically stimulated cochlear implant, and the “new”, optically stimulated cochlear implant. In cases where the auditory nerve is unable to function, there are midbrain and brainstem implants (Auditory Brainstem Implants, ABI), which are designed to create an auditory impression in the brain by bypassing the damaged auditory nerve. However, the hearing impression achieved does not come close to that of the more commonly used cochlear implants.

The light sheet thickness can be adjusted in the Flamingo and adapted to the sample size. The aim is always to have a light sheet that is as homogeneous as possible over the entire sample. For large samples (several millimeters), the light sheet is about 5-20µm thick. The light sheet thickness then also determines the axial resolution of the microscope. The lateral resolution is typically approx. 0.25-3µm, depending on the magnification. By rotating the sample and combining multiple views in the computer, the axial resolution can be improved to achieve near isotropic resolution. For particularly large, transparent samples, a thin sheet of light can also be moved back and forth quickly to achieve a direct isotropic resolution of approx. 0.7µm.

In contrast to the electrical cochlear implant, which is activated electrically, an optical cochlear implant is stimulated by light, as this stimulates the nerve cells of the auditory nerve in a much more targeted way and can therefore improve the hearing result. The sound information is not transmitted electrically, but by light. Since auditory sensory cells are not sensitive to light, they must first be equipped with a corresponding sensor, i.e. made light-sensitive. Light-sensitive ion channels, known as rhodopsins, originally obtained from algae, are used for this purpose. The genetic blueprint of these proteins is introduced into the nerve cells of the auditory nerve using gene therapy. For this purpose, an adeno-associated virus (AAV) is used as a vector, i.e. as a carrier. The viruses are injected into the body as a “shuttle”, with the rhodopsins “in their luggage”, so to speak. These are then stimulated by light irradiation and thus enable the corresponding nerve cells to transmit stimuli.

This method of using genetically foreign, light-sensitive proteins to specifically stimulate or suppress cells is known as optogenetics.

AAV-based therapeutics are used in numerous optogenetic and other gene therapy clinical applications to deliver specific genes into the diseased body. AAVs do not reproduce independently in the human body and are therefore suitable as carriers for gene therapeutics.

The number of animal experiments is difficult to estimate because many of the experiments that, in retrospect, made important contributions to vaccine development were not carried out directly with vaccines in mind, but originated in the fields of cancer therapy and RNA biology. The first successful vaccinations in mice took place in the early 1990s. They showed that the technology could work in principle, but also that the delivery method and stability of the vaccine mRNA needed to be significantly improved. Human clinical trials did not begin until 2013, more than 20 years later.

As experiments on insects, such as the fruit fly Drosophila melanogaster, are not subject to approval, there are no official statistics available.

Intelligence is not the only and not always the best survival strategy. Other strategies have obviously also proved successful in nature. The question of why this characteristic is so pronounced in humans in particular cannot really be answered. We assume that it is a product of chance and selection (= survival).

We assume that there will always be questions that can only be answered using live animals. Therefore, there will always be a certain number of animals that have to be used for animal experiments, even if the aim is to answer as many questions as possible without using live animals. Cloned animals are just as much animals as naturally conceived animals. Cloning is the reproduction of an organism resulting in genetically identical individuals (e.g. offshoots of plants as a natural cloning process). In our view, it would not be an improvement to replace naturally conceived animals with cloned animals, especially as the cloning process could cause additional stress for the animals. Artificially produced organs from “cloned cells”, on the other hand, are a promising approach to replacing animal experiments.

Not all animal experiments are associated with pain for the animals. Minor pain that is also tolerated in humans, for example when taking blood samples or giving injections, is also accepted in animals. If more painful procedures are necessary, pain treatment is prescribed so that the pain for the laboratory animals is minimized. In cases where pain treatment would also be carried out in humans, this is also done in animals.

The tips are used on the one hand to fix the brains and on the other to draw attention to certain points. However, these tips were only attached long after the animal was dead, so that the animal did not feel anything.

Anything that can be examined in single-celled organisms is examined there. Organoids (organ substitutes) and mathematical models are used wherever possible. This is not (always) sufficient for understanding organs or organisms. Organs and organisms still have to be used for this purpose.

The carcasses are incinerated in a disposal facility.

This is possible in principle, but rather unusual in mice. If the death of the animal is not a necessary part (end point) of the animal experiment and no damage, suffering or pain remains and the animal has not been genetically modified, the animal can be given into private hands. This adoption of a former laboratory animal is called “rehoming”. In Germany, the handover of laboratory animals is regulated by the Ordinance on the Protection of Animals Used for Experimental or Other Scientific Purposes (Animal Welfare Ordinance – TierSchVersV).

In stem cell research, there are also many female stem cell lines, not just male ones. But at the level of organoids, we do not expect any major differences between the sex-specific organoids. The differences between women and men, which unfortunately have an impact on healthcare, are at a more complex level (the body) where hormones and corresponding receptors play a role. That is why it is still important to work with a whole organism in research, e.g. the mouse.
In mice, just as in humans, gender plays an important role. Muscle mass, metabolism and hormone concentrations, for example, are gender-dependent. In the past, mainly male mice were used for research, as female mice show a hormonal cycle-dependent behavior (ovulation every 4-5 days). Today, there are great efforts to analyze both genders in order to be able to determine gender-specific differences.

Mice have been kept and bred for scientific purposes for over 100 years. This is a domesticated species. Today there are commercial breeders and scientific animal stables (laboratory animal facilities). The laboratory mice (Mus musculus f. domestica) are bred there as required.

Before an animal experiment is carried out, an intensive examination always determines whether the animal experiment actually needs to be done. Among other things, it must be demonstrated that the scientific question to be answered cannot be achieved with any other animal-free method. Unfortunately, despite intensive efforts, we are not yet in a position to answer all questions without animal testing. Computer models or cell-based systems are not yet able to provide meaningful information, particularly in the case of complex issues that affect the immune system or the nervous system, for example. Without animal testing, for example, we would not be able to develop new medicines (e.g. Covid19 vaccine).
Before the start of each animal experiment, an intensive examination and ethical consideration is carried out, in which animal welfare activists and ethicists are also involved. Here it is weighed up whether the expected gain in knowledge justifies the potential pain, suffering or harm to be inflicted on the animals. Where questions cannot yet be answered without animals, the ethical dilemma arises: no scientific progress (e.g. no new drugs, e.g. against cancer or Alzheimer’s) vs. no animal experiments. Direct testing on humans of new treatment methods that have not yet been tested in other living organisms would be irresponsible and very dangerous. For this reason, we invest a lot of energy in the further development of so-called alternative methods so that animal testing is no longer necessary. Unfortunately, we have not yet reached this point.

Further information on animal testing: https://www.tierversuche-verstehen.de/

According to the German Animal Welfare Act, animals used in animal experiments requiring authorization are counted as laboratory animals. This includes all animals that could suffer damage, suffering or pain in the course of their lives. Accordingly, this includes both genetically contaminated animals and animals on which interventions have been carried out. The killing of genetically uncontaminated animals for organ removal, on which no interventions have been carried out, is not classified as “animal testing” as defined above. Precisely because these animals are not subjected to “pain, suffering or harm” in the course of their lives. These animals therefore do not appear in the statistics as “laboratory animals”, but as animals killed for “scientific purposes”. By using these animals, experiments can be carried out on isolated organs or tissues. As a result, these 29% naturally also contribute to answering scientific questions, which is why we have named them in the graphic, but they do not count as “laboratory animals” in legal terms.

Any intervention for scientific purposes that is potentially associated with pain, suffering or harm to animals is an animal experiment requiring authorization. For this reason, an injection of a NaCl solution (e.g. as an injection to control a test series) is also subject to approval and may only be carried out if the competent authority has approved this project. These animals are counted as laboratory animals.
If an animal that falls ill spontaneously independently of an experiment is treated with NaCl solution (e.g. as a fluid supply to reduce dehydration), then this is a veterinary treatment and not an animal experiment because it is not carried out for “scientific purposes”.

Where animal testing can be reduced or even avoided, this is done. Alternatives are used where possible. For example, organoids, i.e. “organ substitutes”, are created in order to carry out research on them that does not have to be carried out on animals. However, these organoids are only as similar as possible to real organs, never the same. This is due to the fact that a body and its components are very complex and cannot be produced in vitro, i.e. in a test tube in the laboratory. Therefore, if you want to study the brain, it is most meaningful if you actually do this on a real brain. Otherwise, it cannot be ruled out that something will be overlooked that does not occur in the organoid but does occur in the real organ. When new drugs are approved for human use, they must therefore first be tested on a whole, real organism, first on animals and then on humans. Only then can any interactions, side effects or potential harmfulness of the medication be detected. Unfortunately, this is not yet fully replaceable at this time.