More on Longevity and Telomeres- Answers from the Researcher
I recently posted on the new research linking telomere length (telomeres are the protective end caps on DNA) to human longevity.Â This information came from a leading fertility researcher Dr. David Keefe who has discovered the link between telomeres and human egg and embryo health.Â This is a major development that I have called the “unified theory of reproductive aging”.Â It explains longevity, miscarriages, age related declines in fertility among others.Â Even more exciting (or scary) is that this little bit of DNA seems to strongly predict how long you will live.
I had a wave of questions emailed to me so I asked Dr. Keefe to elaborate and clarify some of the most common questions.Â Here is what he said:
1)Â Â Â Â I do not understand why repair mechanisms (telomerase etc) do not correct the damage in the adult organism.Â If it is true that the offspring of an older egg is destined to have short telomeres why is this not repaired?Â Do the necessary enzymes not exist in the adult cell?Â You showed me that there is a repair mechanism in some cells — why does this not fix the problem always?
Very few tissues express telomerase.Â Â Stem cells and cancer cells are the only tissues which express telomerase.Â Eggs and preimplantation embryos, to the blast stage, also do not express appreciable levels of telomerase activity.
2)Â Â Â Â Is there research that offspring of older mothers have short telomeres?
Not yet.Â This whole thing is pretty new. We just had accepted for publication some data suggesting telomeres are longer in eggs from successful vs. unsuccessful IVF cycles
Â 3) Are the telomeres fairly fixed in length in all the sells of one individual?Â Do they shorten with successive cell divisions and normal aging?
Telomeres shorten with aging in somatic cells, both with each division (replicative senescence) and via a mechanism which does not depend on cell division, but rather results from double strand DNA breaks, effected typically by reactive oxygen, and which triggers a DNA double strand break excision repair mechanism. Telomere shortening provides one of the leading theories of how we age.Â In fact telomere length in lymphocytes provides the single best predictor of which geriatric residents of nursing homes will survive and who will die in a given year.Â Telomere length is somewhat fixed in individuals, with genetic, epigenetic and environmental factors contributing to the determination of telomere length, and aging contributing to decreases throughout the year.
Well, since I am the youngest born to a mom in her late 30′s I am eagerly awaiting the gene therapy to fix my short telomeres.Â Check out the original post for all the details.Â