title: Serum oxidized low-density lipoprotein is inversely correlated to telomerase activity in peripheral blood mononuclear cells of haemodialysis patients.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Nephrology, General Hospital of Athens, Greece. tsipg@ath.forthnet.gr
authors.forename: George
authors.initials: G
authors.lastname: Tsirpanlis
authors.forename: Stylianos
authors.initials: S
authors.lastname: Chatzipanagiotou
authors.forename: Fotini
authors.initials: F
authors.lastname: Boufidou
authors.forename: Vasileios
authors.initials: V
authors.lastname: Kordinas
authors.forename: Margarita
authors.initials: M
authors.lastname: Zoga
authors.forename: Fotini
authors.initials: F
authors.lastname: Alevyzaki
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Stamatelou
authors.forename: Eleni
authors.initials: E
authors.lastname: Frangou
authors.forename: Lefkothea
authors.initials: L
authors.lastname: Savva
authors.forename: Chrysoula
authors.initials: C
authors.lastname: Nicolaou
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000276:immunology / Q000378:metabolism; D016922:Cellular Senescence; D005260:Female; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D016753:Interleukin-10 / Q000097:blood; D007676:Kidney Failure, Chronic / Q000276:immunology* / Q000378:metabolism* / Q000628:therapy; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D006435:Renal Dialysis; D019098:Telomerase / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D008077:Lipoproteins, LDL; D014409:Tumor Necrosis Factor-alpha; C099252:oxidized low density lipoprotein; D016753:Interleukin-10; D019098:Telomerase