RESUMEN
BACKGROUND: Telomerase is a cellular enzyme that prevents telomere shortening and promoting viability. The literature has reported shortened telomere length in patients with major depressive disorder (MDD). METHODS: 35 patients with diagnosis of major depressive disorder (MDD) fulfilling DMS-5 criteria in the age range of 18-60 years, treatment-naïve after assessing the severity on HAM-D and HAM-A and 35 age and sex matched healthy controls were included in the study. Baseline peripheral blood monocytes (PBMC) telomerase enzyme was assessed in cases and controls and repeated in cases of MDD at 8th week after intervention with escitalopram for 8 weeks. RESULTS: Pretreatment telomerase activity (TA) was elevated in cases as compared to controls and it was also significantly correlated to the severity of depression (p = 0.00). There was a significant positive difference in telomerase activity between non-responders (higher TA) and responders at baseline (p = 0.001) and 8th week (p = 0.012). The TA did not vary significantly amidst pretreatment and post-treatment, although it was slightly lower in the post-treatment group. LIMITATIONS: The study has few limitations in the form of small sample size, shorter duration of follow-up, and leucocyte telomeres length (LTL) was not assessed. CONCLUSION: The index study concludes that TA is higher in drug naïve patients with MDD than age and sex matched healthy control. The non-responders had significantly higher TA as compared to responders at baseline and post-treatment which indicates TA as a potential biomarker in the underlying biological mechanism of MDD and in response to antidepressant pharmacotherapy.