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Open Access Research article

Telomere shortening in leukocyte subpopulations in depression

Alexander Karabatsiakis1*, Iris-Tatjana Kolassa1, Stephan Kolassa2, K Lenhard Rudolph3 and Detlef E Dietrich45

Author Affiliations

1 Clinical & Biological Psychology, Institute of Psychology and Education, University of Ulm, Ulm, Germany

2 SAP Switzerland, Tägerwilen, Switzerland

3 Leibniz Institute for Age Research, Fritz Lipman Institute, Jena, Germany

4 Burghof-Klinik, Rinteln, Germany

5 Clinic for Mental Health, Hannover Medical School, Hannover, Germany

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BMC Psychiatry 2014, 14:192  doi:10.1186/1471-244X-14-192

Published: 5 July 2014

Abstract

Background

Telomere shortening is a normal age-related process. However, premature shortening of telomeres in leukocytes – as has been reported in depression – may increase the risk for age-related diseases. While previous studies investigated telomere length in peripheral blood mononuclear cells (PBMCs) as a whole, this study investigated specific changes in the clonal composition of white blood cells of the adaptive immune system (CD4+ helper and CD8+ cytotoxic T lymphocytes, and CD20+ B lymphocytes).

Methods

Forty-four females with a history of unipolar depression were investigated and compared to fifty age-matched female controls. Telomere lengths were compared between three groups: 1) individuals with a history of depression but currently no clinically relevant depressive symptoms, 2) individuals with a history of depression with relevant symptoms of depression, and 3) healthy age-matched controls. Telomere length was assessed using quantitative fluorescence in situ hybridization (qFISH).

Results

Both groups with a history of unipolar depression (with and without current depressive symptoms) showed significantly shorter telomeres in all three lymphocyte subpopulations. The effect was stronger in CD8+ and CD20+ cells than in CD4+ cells. Individuals with a history of depression and with (without) current symptoms exhibited a CD8+ telomere length shortening corresponding to an age differential of 27.9 (25.3) years.

Conclusions

A history of depression is associated with shortened telomeres in the main effector populations of the adaptive immune system. Shorter telomeres seem to persist in individuals with lifetime depression independently of the severity of depressive symptoms. CD8+ cytotoxic T cells and CD20+ B cells seem to be particularly affected in depression. The total number of depressive episodes did not influence telomere length in the investigated adaptive immune cell populations.

Keywords:
Depression; Telomere shortening; Aging; Stress; Immunosenescence