Molecular Causes of Aging
Adult stem cells contribute fundamentally to the daily renewal and regeneration of organs and tissue. However, as we get older, stem cells start to lose their function. This is illustrated by clinical observations: Patients suffering from leukemia experience problems with the formation of new blood cells if stem cells in bone marrow transplants are derived from older donors. Experiments in mice also demonstrated that adult stem cell function in different mouse organs and tissue diminishes as a function of age. Affected are hematopoietic stem cells, neuronal, liver, and skin stem cells. For example, an age-related decline in blood stem cell function can make us more susceptible to infections.
The immune system is also tasked with the removal of old and damaged cells from the body. As this ability decreases, the aging process accelerates. It also increases the development of cancer. Malignant tumors generally arise from cells that have accumulated several genetic alterations (mutations.) Ultimately, this leads to uncontrolled cell division and the destruction of organ systems. Since they are the longest-living cells in actively dividing organs, stem cells have a particularly high risk of accumulating mutations. Interestingly, mutations that accumulate in stem cells are the same mutations that occur in malignant tumors.
In the future, it could become feasible to detect dangerous mutations in stem cells before cancer develops; targeted therapies could be used to remove impaired stem cells. Such approaches could revolutionize cancer therapy. Taken together, the latest scientific insights point to age-dependent changes in adult stem cells as a major contributor to the loss of function of organs and tissues as well as the development of cancer.
Understanding the molecular mechanisms of stem cells aging is one of the most important goals of the research focus “Identification of molecular causes of aging and the development of aging-associated diseases.” This knowledge will provide a basis to develop medical therapies, which will help to improve health and reduce cancer risk in old age.