[Life extension study on high-yield non-myeloablating bone marrow transplantation from young to old mice].

Tissue renewal is the known phenomenon, when the progeny of resident or circulated stem cells (SC) replaces the vanishing cells. The delivery of stem cells via circulation should result in stem cell homing and differentiation into wide variety of tissues and gives promise as therapy for many diseases of tissue failure including aging itself. To test this hypothesis, we created chimeric mice C57BL/6 by bone marrow (BM) transplantation from young 1.5 months old donors to 21.5-months old recipient mice of the same strain C57BL/6. We applied here the recently published new transplantation technique, which allows to get high scores of chimerism due to very high amount of transplanted cells (1.5 x 10(8) per mouse or 25% of its total BM count). In the earlier works only 1% of total BM count (about 5 x 10(6) cells per mouse) was usually transplanted to lethally irradiated mice, what excluded the possibility to apply this method for life extension. As a result of the modified technique implementation, the mean post-transplantation life (starting the 21.5 months old) of treated mice was 4.9 months versus 3.4 months for untreated mice. The difference in 1.5 months counts for 44% extension of mean post-transplantation life.