engleski

Effects of chronic stress on telomere length maintenance system and immune function

Telomeres are repeating hexameric sequences of DNA that are found at the ends of linear chromosomes in association with a complex of proteins ; their role is to maintain chromosome integrity and stability. Telomeric DNA is lost due to the incomplete terminal synthesis of thelagging DNA strand during cell division. The rate of telomere loss is retarded by the enzyme telomerase, a RNA-dependent DNA polymerase that synthesizes telomeric repeats and thus maintains telomeres during cell replication. The consequence of chronic stress on telomere length and telomerase activity of Peripheral Blood Mononuclear Cells (PBMCs) was recently reported. Lower basal level of telomerase activity, and shorter telomere length of PBMC were found in mothers of chronically ill children, and shorter telomere length of PBMC in chronically stressed individuals with mood disorders. Post-Traumatic Stress Disorder (PTSD) is an anxiety disorder that can develop after exposure to a terrifying event in which severe physical harm occurred or was threatened. The aim of our study is to investigate the maintenance of telomere length in PBMCs in PTSD patients, or more specific, in subpopulations of lymphocytes in peripheral blood of the patients. Our preliminary data shows that PTSD patients (N=27) have shorter telomeres in PBMCs than their age matched controls (N=18). There was no statisticaly significant difference in telomerase activity between both groups. Further expansions of the study will include measurement of functional characteristics of PBMCs and their relation to telomere length. The study groups will be examined for limphocyte proliferation in response to stimulation PHA, T cell production of cytokines: IFN γ, IL-4 and IL-2 in response to PMA and ionomycin ; monocyte production of TNF alpha and IL-6 in response to stimulation with LPS.

telomere lenght; telomerase; chronic stress; PTSD; PBMC

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