Stem cells are small populations of self-renewing cells which retain the ability to give rise to a limited set of cell types. They support our tissues and organs by dividing to generate new cells as needed. Stem cell exhaustion is a hallmark of aging, and refers to a decline in stem cell numbers and renewal capacity. Without stable populations of proliferating stem cells, tissues and organs lose their ability to recover from damage and begin to fail. This article contains a more detailed description of stem cell exhaustion.
Multipotent stem cells in the bone marrow give rise to a limited selection of cell types.
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Stem cell exhaustion with age results in a clear decline in regenerative capacity, meaning slower recovery from injury and illness. Stem cell exhaustion also impairs the function of the immune system, because there is a reduced ability to generate the necessary types of white blood cells to effectively combat pathogens.