Telomerase Activity and Telomere Length in the Haemopoietic System: Changes with Aging, Disease, and Therapy

Interestingness: 3

By JD Robertson and RF Wynn, in the Journal of Anti-Aging Medicine, Volume 3, Issue 4, 2000 (pp 389-395, doi:10.1089/rej.1.2000.3.389)

Review of what was known about telomere length and telomerase in blood cells. Haemopoietic stem cells (HSC) have active telomerase but their telomeres shorten gradually. Same for T-cells. Telomeres in neutrophils also shorten at about the same rate as in T-cells (20-50 base pairs per year), but from what I understood, they don't have active telomerase, so the telomerase is acting as a compensation method for the occasional clonal expansion of T-cells.

Checking for which X chromosome is inactivated, in old women most blood cells have the same one, as if they come from fewer and fewer stem cells.

In people with acute leukemia, telomeres are short and telomerase long, and they suggest this suggests that telomerase activates late in the process of disease. Also short telomeres on aplastic anemia and Fanconi's anemia.  Also shorter telomeres in bone marrow transplant recipients than in donors (about 15 years worth), but I'm not clear if they are saying this is because the transplanted tissue has had to undergo quick replication to refill the recipient's system, or that this was there before.