title: Vitamin D receptor activation with calcitriol for reducing urinary angiotensinogen in patients with type 2 diabetic chronic kidney disease.
abstract: BACKGROUND
  Recently, it has been reported that urinary angiotensinogen levels is a specific index of the intrarenal renin-angiotensin-aldosterone system (RAAS) status and it is significantly correlated with urinary albumin:creatinine (Cr) ratio in hypertensive patients. The aim of the present study was to assess the effect of activation of the Vitamin D receptor with calcitriol on albuminuria and urinary angiotensinogen as a novel biomarker of the intra-renal RAAS status in patients with diabetic nephropathy (DN).
  
  
  METHODS
  Ninety-eight patients with type 2 diabetes and albuminuria who were treated with RAAS inhibitors (angiotensin-converting enzyme inhibitor (ACE-i) or angiotensin receptor blocker (ARB)) have participated in this study. Patients were randomized to receive either placebo (n = 50) or 0.25 μg/day calcitriol (n = 48). We have examined urinary albumin:Cr ratio and urinary angiotensinogen:Cr ratio before and 24 weeks later after treatment in both group.
  
  
  RESULTS
  The mean urinary albumin:Cr ratio and urinary angiotensinogen:Cr ratio were significantly higher in patients with DN than in normal controls (p < 0.001). Urinary angiotensinogen:Cr ratio was significantly, positively correlated with urinary albumin:Cr ratio in both groups (in the placebo group; p = 0.01, r = 0.4236, in calcitriol group; p = 0.01, r = 0.4564).
  
  
  CONCLUSIONS
  These data indicated that administration of Vitamin D receptor activator in combination with RAAS inhibitors had an additional benefit in lowering albuminuria in patients with DN. More pronounced reduction of urinary albumin:Cr ratio that was positively correlated with angiotensinogen:Cr ratio in calcitriol group suggested that Vitamin D receptor activation might blunt albuminuria by reducing urinary angiotensinogen levels reflecting intra-renal RAAS status.
authors.affiliation: a Department of Nephrology , Gaziantep University School of Medicine , Gaziantep , Turkey ;
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Tiryaki
authors.affiliation: a Department of Nephrology , Gaziantep University School of Medicine , Gaziantep , Turkey ;
authors.forename: Celalettin
authors.initials: C
authors.lastname: Usalan
authors.affiliation: b Department of Endocrinology & Metabolism , Gaziantep University School of Medicine , Gaziantep , Turkey.
authors.forename: Zeynel Abidin
authors.initials: ZA
authors.lastname: Sayiner
mesh_terms: D000419:Albuminuria / Q000188:drug therapy*; D000808:Angiotensinogen / Q000187:drug effects* / Q000652:urine*; D002117:Calcitriol / Q000494:pharmacology* / Q000627:therapeutic use; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000150:complications / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018167:Receptors, Calcitriol / Q000187:drug effects*; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000652:urine*; D012084:Renin-Angiotensin System / Q000187:drug effects
chemical_list: D018167:Receptors, Calcitriol; D000808:Angiotensinogen; D002117:Calcitriol
keywords: Calcitriol; albuminuria; pre-dialysis diabetic patients; urinary angiotensinogen