Enzyme Activity Linked to Major Depression

Sharon Moore May 31, 2013

An enzyme, called telomerase, found within the cells of the immune system, works by lengthening the protective end caps on the chromosomes’ DNA, called telomeres. In previous studies, shortened telomeres have been linked to a higher risk of early death and chronic disease. Now, a research team from the UC San Francisco has found that the activity in the enzyme may also play a role in the case of major depression.

According to the lead author, Owen Wolkowitz, MD, Professor of Psychiatry at UC San Francisco, the heightened telomerase activity represents the body’s attempt to fight back against the progression of disease in order to prevent biological damage in long-depressed individuals.

Their study involved 20 depressed individuals who had been untreated for at least six weeks and had average lifetime duration of depression for about 13 years. After evaluating the laboratory measures, 16 of the study participants were treated with a specific type of antidepressant. After eight weeks, they were again evaluated.

The researchers found that in untreated individuals with major depression, the activity of the enzyme telomerase is greater. Looking at the MRI scan, they also found that, in untreated depressed individuals, the size of the hippocampus was associated with the amount of telomerase activity in the white blood cells. Wolkowitz said that even though such association is not enough to conclude that telomerase helps protect the hippocampus, it is possible.

Surprisingly, they also found that in some depressed individuals who began taking antidepressants, the enzyme’s activity went up. Those with lower telomerase activity at baseline as well as those whose enzyme activity increased the most during treatment were the most likely to become less depressed with the treatment. Wolkowitz stressed that these findings were consistent with previous research showing the beneficial effects of boosted telomerase in animal models. Just recently, researchers at Copenhagen University found that the enzyme has a rejuvenating effect on a normal ageing cell.

But due to the size of the study, Wolkowitz said that more research is needed to confirm their findings.

Areas for Further Research

Wolkowitz and his team will also be investigating the role of chronic inflammation and the biochemical phenomenon of oxidative stress which is often reported in major depression. They theorised that inflammation and oxidative stress shortens the telomeres, which in turn lead to depression and increases the rate of ageing. Wolkowitz said that new insights to this area could lead to new treatments, both pharmacological and behavioural, that will be different from the current treatment strategies employed today. He also emphasised the possibility of creating a simple blood test that can measure accelerated immune-cell ageing.

Source of this article:

Depression Linked to Telomere Enzyme, Aging, Chronic Disease