title: Assessment of the potential role of active vitamin D treatment in telomere length: a case-control study in hemodialysis patients.
abstract: BACKGROUND
  Telomeres are special chromatin sequences located at the end of eukaryotic chromosomes, protecting these regions from recombination and degradation. Previous studies have reported a decrease in telomere length on white blood cells from hemodialysis (HD) patients, which suggests premature senescence. Active vitamin D treatment has been reported to have an effect on telomere length and beneficial effects on HD patients, but the mechanisms are unknown.
  
  
  OBJECTIVE
  Our aim was to assess the potential protective role of active vitamin D treatment on telomere length in peripheral mononuclear cells (PBMC) from HD patients.
  
  
  METHODS
  A retrospective case-control study of 62 stable HD patients and 60 healthy sex-matched controls was undertaken. Telomere length was measured in PBMC by Southern blot. After telomere length measurement, 5 control samples that did not reach quality-control standards were excluded. Standard epidemiological and biochemical parameters were recorded. Blood biochemistries were performed at the Biochemistry Department of the University Hospital Arnau de Vilanova in Lleida, Spain, using standard routine techniques. Differences in telomere length were analyzed using Student's t test. Multiple regression analysis examined the independent contribution of the factors that significantly affected telomere length in the bivariate analysis.
  
  
  RESULTS
  HD patients presented shorter telomere length in PBMC, independent of age and sex (mean [SD] 8.8 [1.5] kbp vs 10.5 [2.9] kbp; P = 0.0001). Multivariate regression analysis of the HD subgroup suggested that patients under active vitamin D treatment have greater telomere length in PBMC than untreated patients (9.5 [0.2] kbp vs 8.4 [0.2] kbp; P = 0.003).
  
  
  CONCLUSIONS
  HD patients were observed to have decreased PBMC telomere length compared with healthy controls. HD patients treated with active vitamin D compounds had greater PBMC telomere length than untreated patients. Prospective studies are required to assess the potential role of active vitamin D treatment in PBMC telomere length.
authors.affiliation: Nephrology Department, Hospital Universitario Arnau de Vilanova, Lleida, Spain.
authors.forename: Mercè
authors.initials: M
authors.lastname: Borras
authors.forename: Sara
authors.initials: S
authors.lastname: Panizo
authors.forename: Felipe
authors.initials: F
authors.lastname: Sarró
authors.forename: Jose M
authors.initials: JM
authors.lastname: Valdivielso
authors.forename: Elvira
authors.initials: E
authors.lastname: Fernandez
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016615:Telomere / Q000187:drug effects*; D014807:Vitamin D / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D