Telomere length predicts lifespan. Now, a new study has shown an association between childhood trauma, shortened telomere length and mental illnesses such as bipolar mood disorder and schizophrenia. Hmmm… What’s that telling us?
Cell division is essential to life and telomeres are part of that process. Telomeres are protective caps on the end of DNA strands and are comprised of region of repetitive nucleotide sequences. They have been likened to the plastic tips on the end of shoelaces. Telomeres protect chromosomes from damage while cell division takes place, and also prevent the end of the chromosome fusing with other chromosomes.
Each time cell division occurs, your telomeres get shorter. This shortening happens because DNA polymerases, the enzymes that duplicate DNA, cannot copy all the way to the end of a chromosome. Consequently, after every duplication the end of the chromosome is shortened slightly. Eventually, a limit is reached when the telomere is too short and cell division is no longer possible. This is called the Hayflick Limit. A normal human cell can only replicate and divide some 40 to 60 times before reaching the Hayflick Limit and thereafter it is destroyed by apoptosis.
The shortening of telomeres is offset by an enzyme called telomerase. Telomerase splices telomeric DNA (T2AG3 repeats) onto the ends of the telomere, increasing the length and counteracting the shrinkage caused by cellular replication.
The Good, the Bad & the Ugly
Now, you shouldn’t think that the shortening of telomeres is necessarily all bad. After all, our genetic blueprint functions in such a way that our cells die off naturally. When this process goes awry, one potential consequence is cancer. In many types of cancer, telomere length is maintained by telomerase. As a result, cancer cells attain a kind of immortality because the natural process of dying off due to telomere shortening does not take place. Interestingly, some cancer treatments now specifically targeted telomerase.
Given these various facts, is not surprising that telomere length has been proposed as a proxy for cellular ageing, although the concept is arguably in need of refinement. Telomere length is indeed linked to lifespan, at least in zebra finches who don’t live for very long and are therefore convenient to study when investigating lifespan. Researchers have shown that telomere length early in life is a very strong predictor of longevity.
A landmark study published in 2004 showed that psychological stress was linked to shortened telomere length, reduced telomerase activity and higher oxidative stress. This shifted the focus away from physical illnesses such as cancer, diabetes and cardiac disease and expanded our view to consider the relationship between mental life, cellular replication, and telomere length.
Telomeres, Schizophrenia and Bipolar Mood Disorder
A recent study investigated childhood trauma in patients with a diagnosis of schizophrenia or bipolar mood disorder. Compared to healthy controls, telomere length was shorter in the patients with mental illness and they reported more childhood trauma than controls. Patients who had a history of childhood abuse, be it emotional, physical or sexual abuse, had shorter telomeres than healthy controls and patients who had no history of childhood abuse.
These findings would suggest there is a specific effect arising from emotional, physical or sexual abuse that is associated with shortened telomere length. In that regard, it is relevant that abuse is a particularly stressful experience. One characteristic feature of abuse is the experience of being out of control, of being unable to do anything to change the situation. That belief is particularly psychologically damaging. In the long-term, the experience of being unable to influence a stressful situation may cause structural changes in the brain, although in this study there was no association between telomere length and brain morphology.
A recent meta-analysis of the relationship between perceived stress and telomere length identified a statistically significant relationship between perceived stress and telomere length after adjusting for age. The age adjustment is important because telomere length systematically shortens as we get older.
The good news is that robust research has shown that it is possible to turnaround cellular ageing and increase telomere length through a programme of comprehensive lifestyle changes that target diet, exercise, stress management, psychotherapy and social support. To put that into different words, love, good friends, healthy food, and some exercise will go a long way to solving your emotional problems and simultaneously lengthen your telomeres and give you long life!!