How is it that autologous stem cell therapies work? From ScienceDaily: new work is "shedding light on the previously mysterious mechanism through which even relatively small amounts of stem/progenitor cells taken from a patient's own bone marrow enhance repair of damaged tissues. ... The cells not only differentiate to replace injured cells, as had been understood, but they also stimulate the proliferation and differentiation of stem cells already present in the injured tissue and they transfer mitochondrial DNA to local cells in which the mitochondria (the energy of the cell) is not working. Better understanding of the different mechanisms of these stem/progenitor cells suggests multiple strategies for developing new therapies for a broad range of diseases. ... the studies are explaining the mechanisms by which the cells work, in animals and in the more than 1,000 cardiovascular and other patients in the United States believed to be enrolled in clinical trials using these cells taken from their bone marrow." The mitochondrial transfer is certainly interesting. Could we make inroads in repairing age-damaged mitochondria via the application of stem cells in addition to the more obvious methods?