Stressful childhood accelerates the ticking of the cell clock

A University of Helsinki study shows that difficult childhood experiences can exhibit themselves in adulthood as shorter white blood cell telomeres. However, the cell clock can be rewound with a healthy lifestyle.

Telomeres, referred to as the cell’s biological clock, are structures that protect the chromosomal ends, which shorten while the cell is replicating; when shortening surpasses a certain limit, the cell can no longer replicate and dies. The telomere shortening is prevented by telomerase, an enzyme that repairs their structure and functions actively in stem cells and gametes. In somatic cells, telomerase activity is low and decreases with age.

In addition to ageing, telomere shortening has been linked to various diseases, including cardiovascular diseases and cancer. Smoking and obesity accelerate telomere shortening, as does psychological stress.

- Since childhood psychological stress, in particular, is a significant factor in the development of anxiety disorders, we wanted to find out whether telomere shortening was also linked to anxiety disorder, says Iiris Hovatta, Docent and Academy Research Fellow, whose research group is a part of the Research Program of Molecular Neurology at the Faculty of Medicine.

The study data comprised 300 individuals with anxiety disorders and 600 control subjects.

- When looking at the data in its entirety, there was no difference in the telomere length between the patient and control groups. But when studying the older age group from 48 years upwards, the telomeres of the anxiety disorder sufferers were shorter than those of the control subjects, says Hovatta.

However, the most intriguing finding was that a stressful childhood was clearly evident in telomeres of both the patients and the control subjects. This became evident when the researchers studied the whole data with regard to difficult childhood experiences of the participants. They included mental health and alcohol problems of the parents, divorce, getting bullied at school as well as individual severe physical or prolonged disease.

- The more stressful events people had experienced, the shorter their telomeres in adulthood were. This applied both to anxiety disorder sufferers and the control group.

Severe or long-term childhood disease appeared to have the strongest effect on telomere length.

- It is known that oxidative stress decreases the activity of the telomerase enzyme in cells, so perhaps the biological mechanism can be found in that direction, speculates Hovatta.

Fortunately, a stressful childhood is not a final judgement for telomeres: research suggests that it is possible to increase the activity of the telomerase enzyme through a healthy lifestyle. Iiris Hovatta toys with the idea that telomere length could serve as a biomarker of general health.

- It could be that the healthier you are, the longer your telomeres are.

Hovatta's study in the science journal PLoS One in May 2010 » »

Text and photo: Päivi Lehtinen
22.7.2010
Translation: AAC Global
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