Aging expert Aubrey DeGrey in ENDING AGING has a theory that "gunk" buildup inside cells causes aging
The "gunk" is relatively inert garbage build-up over time. It has several forms, and has been given different names in different areas of research, e.g. heart, brain, etc. but all forms may be related to lysosome malfunction. Lysosomes are our little garbage collectors (as the mitochondria are our little power plants.)
Furthermore, DeGrey states that heart cells and brain cells do not divide, and that only small parts of the brain tissue are regenerated (by stem cells in the brain.) Since cells that divide lose half their "gunk" to daughter cells, it is the non-dividing heart and brain cells that face the biggest difficulty from the build-up of "gunk" with age.
Here is the conundrum. If DeGrey is correct, then starting around age 65, the rate of Alzheimer's/Dementia doubles every year, and if you don't die of something else you will become demented.
Telomeres are only relevant in cells that divide.
If the brain and heart cells do not divide, and the brain cells are not regenerated, then the telomeres are useless strands at the ends of chromosomes in these non-dividing cells. This seems to imply that something is wrong in River City, i.e., that something is fundamentally wrong with the idea that telomere lengthening can "end aging."
Sure we die when our dividing cells burn out from short telomeres, but on the surface, telomeres would have little to do with brain (and heart) aging.
Now one answer may be Vitamin E - as discussed elsewhere - as vitamin E has been shown to be helpful for both brains and hearts, and the gunk build-up may even be the vitamin E deficiency disease. So enough vitamin E, no gunk, no problem.
But as I was about to email Dr. Andrews asking his opinion about this conundrum, when the possible answer occurred to me. The answer also comes from the book Aubrey DeGrey book ENDING AGING, and while fascinating, I think I'll leave this as a challenge to any reader. (For awhile).
If brain cells don't divide, and brain cells develop plaques - inside and out - how could extending telomeres prevent the inevitable dementia?