title: Effect of vitamin D supplementation on endothelial dysfunction in hemodialysis patients.
abstract: Patients with chronic kidney disease (CKD) commonly experience 25-hydroxyvitamin D3 (25-OH-D3) deficiency, and these patients have a higher incidence of cardiovascular diseases (CVDs) due to endothelial dysfunction (ED). The aim of our study was to investigate the effect of 25-OH-D3 deficiency and its supplementation on ED in patients with CKD.
  
  
  
  Twenty-nine uremic patients on dialysis and 20 healthy controls were evaluated for ED by high-resolution Doppler ultrasonography of the brachial artery. In addition, 25-OH-D3-deficient patients (25-OH-D3 < 30 nmol/L) with CKD and healthy controls were evaluated for ED before and after 8 weeks of oral vitamin D (cholecalciferol, 50,000 units) treatment. All subjects were evaluated for percent flow-mediated dilatation (%FMD), percent endothelium-independent nitroglycerin-induced vasodilatation (%NID), and bilateral carotid intima-media thickness (CIMT).
  
  
  
  Patients on dialysis had lower %FMD and %NID 6.11 [2.27-12.74] and 10.96 [5.43-16.4], respectively, than controls 15.84 [8.19-22.49] and 21.74 [12.49-29.4], respectively (P < 0.05). Patients on dialysis had higher left and right CIMT (0.79 ± 0.15 and 0.78 ± 0.14, respectively) than controls (0.60 ± 0.09 and 0.59 ± 0.09, respectively; P < 0.05). In 25-OH-D3-deficient patients with CKD, after vitamin D treatment, %FMD was significantly increased in dialysis patients (10.25 [7.8-12.8]) compared to before supplementation (5.4 [2.77-6.15]; P < 0.001).
  
  
  
  These results indicated that dialysis patients had significantly lower blood 25-OH-D3 levels and higher CIMT than healthy subjects. In addition, vitamin D supplementation improved ED and increased %FMD in dialysis patients. Our findings suggest that vitamin D supplementation in dialysis patients might prevent CVD.
authors.affiliation: Department of Medical Oncology, Cancer Institute, Hacettepe University, Ankara, Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Karakas
authors.affiliation: Department of Nephrology, School of Medicine, Osmangazi University, Eskisehir, Turkey.
authors.forename: Garip
authors.initials: G
authors.lastname: Sahin
authors.affiliation: Department of Radiology, School of Medicine, Osmangazi University, Eskisehir, Turkey.
authors.forename: Furkan Ertürk
authors.initials: FE
authors.lastname: Urfali
authors.affiliation: Department of Biostatistics, School of Medicine, Osmangazi University, Eskisehir, Turkey.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Bal
authors.affiliation: Department of Radiology, School of Medicine, Osmangazi University, Eskisehir, Turkey.
authors.forename: Nevbahar Akcar
authors.initials: NA
authors.lastname: Degirmenci
authors.affiliation: Department of Pharmacology, School of Medicine, Osmangazi University, Eskisehir, Turkey.
authors.forename: Basar
authors.initials: B
authors.lastname: Sirmagul
mesh_terms: D000328:Adult; D000368:Aged; D019587:Dietary Supplements / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D051436:Renal Insufficiency, Chronic / Q000150:complications*; D014807:Vitamin D / Q000097:blood / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D
keywords: 25-Hydroxyvitamin D3; carotid intima-media thickness; cholecalciferol; endothelial dysfunction; flow-mediated dilatation