The Promise of Stem Cell Rejuvenation
Stem cell function, necessary to maintain tissue, declines with age. This most likely a part of the evolved balancing act between suppression of cancer and the need to keep tissues repaired and working - as you grow older, forms of molecular damage accumulate, increasing the risk of cancer resulting from the normal operations of cellular proliferation. That balance can already be shifted in mice in very beneficial ways, giving both less cancer and longer lives. While these are the early days yet, in our future lies a fusion of the fields of cancer research and stem cell science that will do the same for humans: "Adult stem cells exist in most mammalian organs and tissues and are indispensable for normal tissue homeostasis and repair. In most tissues, there is an age-related decline in stem cell functionality but not a depletion of stem cells. Such functional changes reflect deleterious effects of age on the genome, epigenome, and proteome, some of which arise cell autonomously and others of which are imposed by an age-related change in the local milieu or systemic environment. Notably, some of the changes, particularly epigenomic and proteomic, are potentially reversible, and both environmental and genetic interventions can result in the rejuvenation of aged stem cells. Such findings have profound implications for the stem cell-based therapy of age-related diseases."