Telomerase activity is decreased in peripheral blood mononuclear cells of hemodialysis patients.

BACKGROUND Telomerase preserves telomere length and structure, preventing cellular senescence, which is associated with alteration of the chromosomal ends. We hypothesized that telomerase activity is altered in peripheral blood mononuclear cells (PBMCs) of hemodialysis (HD) patients. To investigate this hypothesis as well as the relationship between telomerase and inflammation, we measured the activity of this reverse transcriptase as well as the level of several inflammatory markers in PBMCs and serum of an end-stage renal failure (ESRF) population and a non-renal-failure group of subjects. METHODS In PBMCs isolated from 42 HD and 39 non-renal-failure subjects of the same age (51.0 +/- 12.4 and 51.4 +/- 12.1 years, respectively) telomerase activity was measured using PCR-ELISA; the method was based on the telomeric repeat amplification protocol. RESULTS Telomerase activity in PBMCs was detected in 18 (42.9%) HD and 28 (71.8%) non-renal-failure subjects (p = 0.013). Among positive subjects, percent telomerase activity in PBMCs was significantly higher in non-renal- failure (117 +/- 112 %) than in HD (47.6 +/- 57.1 %) subjects (p = 0.008). Detectable telomerase activity was lower in long-term than in short-term HD patients (13.3 +/- 8.9 vs. 75.0 +/- 64.8%, respectively, p = 0.015). Although higher in HD group, inflammatory indexes (C-reactive protein, interleukin-6, IL-6, soluble IL-6 and soluble gp130) were not correlated to telomerase activity in PBMCs. CONCLUSION Telomerase activity in PBMCs is reduced in HD patients. It seems that, at least in this type of cell in this population, defense from senescence, as assessed by telomerase activity, is altered and associated with the chronicity of uremia/HD procedure.