Telomere Length And Brain Age

Telomere shortening is considered to be a measure of the human biological clock, longer ones indicate a lower risk of certain metabolic diseases and younger cells, but they can also predict a greater risk of certain cancers. These protective end caps are a bit of a paradox, but they clearly correlate to aging and whether lengthening them may be an intervention to delay or reverse aging in humans remains to be seen. 

As cells replicate and divides a few of the genetic sequences at the end of each chromosome gets missed. Telomeres are made of the same sequences of nucleotides that repeat over and over again, this is to cap of the chromosomes to prevent key genetic material from being lost in the division process as when one of the telomere sequences get lost in division no harm is done. However, telomeres are not able to shorten protectively indefinitely, once they reach a certain length, the cell can no longer divide. 

Telomeres are vital for our survival as the also protect against uncontrolled cell division that leads to cancer, making finding ways to extend or prolong their length important. Their natural protective role is not the only thing that can shorten telomeres, they can also be shortened by genetics and unhealthy lifestyle choices. Telomeres can also be lengthened with enzymes, a healthy diet, and exercise. 

The Planck Institute researchers investigated whether changes in telomere length were linked to biological aging, Lara Puhlmann explained,  “To explore whether a short-term change in telomere length, after only a few months, might actually be associated with changes in a person’s biological age, we linked it to another biomarker of aging and health: brain structure.”

In this study participants had 4 MRI exams that were three months apart, and they provided blood samples at the same dates. Examining the DNA of leukocytes from their blood samples enabled the team of researchers to calculate telomere length by using a polymerase chain reaction: the outer layer of brain grey matter thins with age, the MRI scans were used to calculate the thickness of the cerebral cortex for all of the participants in this study. 

Puhlmann commented on the team’s findings: “Across systems, our biological aging appears to change more quickly than we thought. Indices of aging can vary together significantly in just three months.”

Lengthening of telomeres was found to be associated with thickening of the cortex while shortening was associated with decreases in grey matter having some similarities to symptoms exhibited by those who suffer from dementia; changes in the brain occurred the precuneus which is a central metabolic and connectional hub. 

Results suggest that changes in grey matter and telomere length may reflect changes in health and biological age, but the research team suggests that more work is required to confirm and build and these findings. “We do not know, for example, which biological mechanism underlies the short-term changes in telomere length,'' explained Puhlmann, “or whether the short-term changes really have a longer-term effect on health.”