Invigorating Old Stem Cells
Researchers are working their way around the signalling mechanisms that damp down stem cell activity with age. From EurekAlert!: "As we age, our stem cells are prevented, through chemical signals, from doing their jobs ... the stem cells in old tissue are still ready and able to perform their regenerative function if they receive the appropriate chemical signals. Studies have shown that when old tissue is placed in an environment of young blood, the stem cells behave as if they are young again ... Aging and the inevitable march towards death are, in part, due to the progressive decline of Notch and the increased levels of TGF-beta, producing a one-two punch to the stem cell's capacity to effectively rebuild the body ... But what would happen if researchers blocked the adult stem cells in old tissues from reacting to those TGF-beta signals? ... muscles in the old mice whose stem cell 'aging pathway' had been dampened showed levels of cellular regeneration that were comparable to their much younger peers, and that were 3 to 4 times greater than those of the group of 'untreated' old mice." The decline in function exists to protect against cancer - but if researchers solve that problem too, it seems we can get much more from our stem cells.
Link: http://www.eurekalert.org/pub_releases/2008-06/uoc--scr061108.php