Background: Telomerase preserves telomeres' function and structure preventing cellular senescence. Its activity is reduced in peripheral blood mononuclear cells (PBMC) of haemodialysis (HD) patients. The purpose of this study is to investigate the potential correlation between increased oxidative stress/inflammation and telomerase activity in PBMC of HD patients.
Methods: Telomerase activity was measured by PCR-ELISA in PBMC isolated from a group of 42 HD patients and 39 subjects with estimated glomerular filtration rate >or=80 mL/min (control group). Serum oxidized low-density lipoprotein (ox-LDL), tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) were also measured in both groups by ELISA.
Results: Ox-LDL was negatively correlated to percentage telomerase activity in PBMC (r = -0.506, P = 0.000 in the whole group of 81 HD and normal subjects and r = -0.559, P < 0.001 in HD patients). TNF was also inversely associated with percentage telomerase activity in the whole group studied (r = -0.492, P = 0.000) while IL-10 was not. In stepwise multiple linear regression, taking into consideration the most important characteristics of the HD patients and control group, the only significant predictors for percentage telomerase activity in PBMC were ox-LDL and TNF (beta = -0.421, t = -4.083, P = 0.000 and beta = -0.381, t = -3.691, P = 0.000, respectively) while examining separately HD patients, the predictors for the same parameter were ox-LDL and HD duration (beta = -0.671, t = -4.709, P = 0.000 and beta = -0.349, t = -2.447, P = 0.023, respectively).
Conclusion: Ox-LDL serum level is inversely correlated to telomerase activity in PBMC of HD patients. Our study proposes a new consequence of increased oxidative stress in HD patients: the premature cellular senescence potentially related to atherosclerosis through LDL oxidation.