Stem Cells and the Regeneration of Contractile Tissues

Adult stem cells have attracted a lot of attention because of their capacity to self-renew and their high plasticity. These properties enable adult stem cells to generate diverse cell progenitors that actively participate in tissue maintenance by replenishing cells that repopulate the tissues/organs during a lifespan and regenerate damaged tissues during injury.

Principally, embryonic, fetal, and adult stem cells show several common features such as a high self-renewal capacity and the potential to generate different cell progenitors of different lineages. The functional properties of stem cells indicate that they contribute to the regeneration of damaged tissues. Therefore, the use of stem cells and their progenitors is a promising strategy for cellular and genetic therapies to treat different disorders.

The identification, characterization, and understanding of stem cells differ significantly in different organ systems. In the skeletal muscle system muscle stem cells can be identified readily since they reside as satellite cells on myofibers and express numerous well-defined markers. Yet, it is still not clear whether the ability of satellite cells to renew themselves suffices to maintain the stem cell pool or other cells, which are either resident or circulatory, replenish satellite cells. In the myocardium the situation is not as clear although numerous studies suggest that myocardial cells undergo a certain degree of turnover. Several different cell types, which can be found in the myocardium or in the circulation have been claimed to contribute to this process although definitive proof about the identity, the properties, and the extent of contribution to tissue renewal of such cells is still missing.

The newt Notophthalmus viridescens seems to follow a different route. Newts are able to reverting differentiation, thereby acquiring a more immature state that facilitates cell proliferation and regeneration of complex structures even after amputation. Projects in the department seek to explore the biology of stem cell based tissue regeneration in contractile tissues such as the heart and skeletal muscle. These endeavors are complemented by a comprehensive approach to understand organ regeneration in newts. We reason that each scheme will benefit from the other.