Animal Physiology

Why can some animals simply regenerate injured tissue, while humans instead develop scars? The team of the Animal Physiology division led by  Prof. Dr. Kerstin Bartscherer investigates this question – using modern 3D in vitro models and regenerating animals to unravel the secrets of regeneration and inspire new therapeutic approaches.

Planarians – masters of tissue regeneration

The undisputed masters of regeneration are planarians, which belong to the flatworms (Platyhelminthes). Some planarians can be cut into hundreds of pieces: each individual piece regenerates the lost tissue, even the head, within a few days. The building material for regeneration in these animals are stem cells, which divide after injury and transform into the required cell types. For example, a stem cell can develop into nerve cells, skin cells or intestinal cells. In the laboratory, we use planarians to better understand the behaviour of stem cells during regeneration and to learn about the mechanisms that control their behaviour.

Scar-free regeneration in spiny mice

Why does the spiny mouse regenerate its tissue while other mammals form scars? To find answers to this question and use our knowledge to develop approaches for regenerative therapies, we compare the cellular and molecular processes that take place after injury in spiny mice or their non-regenerating relatives, house mice. For example, by comparing the activity of certain genes, we can infer the behaviour of cells. Through this, we have already discovered that both the immune response and the reaction of connective tissue cells differ. We are conducting further studies to investigate whether these differences are relevant to the regenerative capacity of spiny mice.

Human skin organoids for modelling scar formation and other pathologies

In order to transfer our findings from animal models to humans, we develop human 3D in vitro systems, such as skin organoids, from pluripotent stem cells (iPS cells). These mini-organs are created through self-organising developmental processes that normally occur during embryogenesis. The resulting skin organoids not only contain all skin layers and cell types, e.g. keratinocytes and melanocytes, but also glands and hair follicles. With the help of this “mini-skin”, we want to replicate regeneration processes and model diseases such as melanoma in order to map and understand the relevant cells and molecules in their natural surroundings.