title: Effects of angiotensin II receptor antagonist on endothelial vasomotor function and urinary albumin excretion in type 2 diabetic patients with microalbuminuria.
abstract: BACKGROUND
  Microalbuminuria is associated with dysfunction of the vascular endothelium in patients with diabetes mellitus. The objective of the present study was to determine whether treatment with losartan at a dose sufficient to lower urinary albumin excretion was accompanied by an improvement in endothelial function in type 2 diabetic patients with microalbuminuria.
  
  
  METHODS
  Endothelial function was measured in 80 type 2 diabetic patients with microalbuminuria and 68 non-diabetic controls using high-resolution vascular ultrasound. The diabetic patients were randomised to receive either losartan 50 mg daily or placebo in a 6-month double-blind study. Urinary albumin excretion and endothelial function were assessed at baseline, 3 and 6 months.
  
  
  RESULTS
  Both endothelium-dependent (p<0.01) and -independent vasodilation (p<0.01) were significantly impaired in diabetic patients with or without history of hypertension compared to the non-diabetic controls. At baseline, the losartan- and placebo-treated groups were comparable in their clinical characteristics. Blood pressure did not change significantly in either group throughout the study. Urinary mean albumin excretion rate (MAER) decreased in the losartan-treated group (p<0.01) whereas an increase was observed in the placebo group (p<0.05). At 6 months, the losartan-treated group had significantly lower MAER than the placebo-treated group [54.5 (58.3) vs 78.5 (100.5) microg/min, p<0.05; median (interquartile range)]. No significant differences were found in endothelium-dependent or -independent vasodilation.
  
  
  CONCLUSIONS
  Type 2 diabetic patients with microalbuminuria have impaired endothelium-dependent and -independent vasodilation. Treatment with low-dose losartan is sufficient to reduce microalbuminuria in these patients without alteration in endothelial function and systemic blood pressure.
authors.affiliation: Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China. kcbtan@hkucc.hku.hk
authors.forename: Kathryn C B
authors.initials: KC
authors.lastname: Tan
authors.forename: Wing-Sun
authors.initials: WS
authors.lastname: Chow
authors.forename: Victor H G
authors.initials: VH
authors.lastname: Ai
authors.forename: Karen S L
authors.initials: KS
authors.lastname: Lam
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000188:drug therapy*; D057911:Angiotensin Receptor Antagonists; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000503:physiopathology; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006801:Humans; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010919:Placebos; D014664:Vasodilation / Q000187:drug effects
chemical_list: D057911:Angiotensin Receptor Antagonists; D010919:Placebos; D019808:Losartan