David Harrison showed to that bone marrow could be successfully transplanted through several generations of mice. There are several references with all of the caveats. Here is one of the earlier ones.
SheldonJ Gerontol. 1975 May;30(3):279-85.Normal function of transplanted marrow cell lines from aged mice.Harrison DE.AbstractTransplantation experiments indicated that losses with age in erythrocyte production were not intrinsically timed within marrow cell lines. In most cases marrow cell lines from old donors functioned as well as those from young donors after transplantation into either W/W-v anemic or lethally irradiated normal recipients. After normal marrow cells had been serially transplanted into successive W/W-v mice 5 times, both old and young cell lines began to fail; the old cell lines had produced erythrocytes normally for 77 to 84 mo. Transplanted old and young control marrow cell lines, identified by T6 chromosomes, saved the lives of lethally irradiated recipients; the oldest cell lines functioned normally for 54 mo. The hypothesis is suggested that senescence of an organism is caused by intrinsically timed functional declines in only a few vital cell types. In transplantation experiments to identify these cell types, four criteria–function, identification, control, and health–should be met. The marrow transplantation experiments led to and illustrate the hypothesis and the four criteria.PMID: 1091693
On Sat, Mar 14, 2015 at 5:38 PM, Thomas Coote wrote:
Would you be able to supply a reference to show that transplanted organs (old to young) can function for two lifetimes?
I understand your reasoning for the process by which this might happen, but I am unable to find a reference to it.
On Sat, Mar 14, 2015 at 9:45 PM, Dr. Harold Katcher wrote:
Please read my response to Josh. The fact that a transplanted organ (transplanted from an aged donor to a young recipient), can live and function for two lifetimes at least informs us that its tissues must have been changed so that they can regain a lost lifetime, that is they become functionally younger and capable of extreme life extension (multiples of the normal lifespan). How could they do that if their telomeres remained at the basal level left them when they were in dysfunctional, aged organs? It must be the case the the telomeres grow back – or how else could the organ last another lifetime? My guess is – based on the same reasoning – that senescent cells will also be eliminated at least once the immune system is rejuvenated – because how could the organ return to full functionality if 15-30% of its cycling cells are senescent? In the absence of immune system rejuvenation (which there is evidence to indicate may take a longer time to rejuvenate than other tissues) perhaps the answer eliminating the stem cells requires additional treatment with senescent-cell eliminating drugs? Like all the other ’causes’ of aging – removing senescent cells gives an increase in life expectancy of about twenty, twenty-five percent. While who would oppose adding a decade or two of healthy years to their lives – I want to go much, much further with increases in lifespan multiples of today’s lifespans.