title: Calcitriol supplementation improves endothelium-dependent vasodilation in rat hypertensive renal injury.
abstract: OBJECTIVE
  Vitamin D increases renal expression of klotho in normotensive rats. Klotho reduces oxidative stress.
  
  
  METHODS
  In this study, we aimed to determine if vitamin D would suppress oxidative stress using 4 groups of hypertensive rats: uninephrectomized, stroke-prone, spontaneously hypertensive rats fed a high-salt (6%) diet (controls; C); those treated with irbesartan (I); those treated with calcitriol (V); and those treated with both irbesartan and calcitriol (I+V).
  
  
  RESULTS
  Systolic blood pressure was higher in the C group than in the I and I+V groups. Albuminuria was attenuated in groups I, V, and I+V. Renal angiotensin II (AngII) concentration was lower in groups I and I+V than in group C, and plasma AngII levels of groups I and V were higher and lower than those in group C, respectively. Compared with group C, renal klotho expression, 8-epi-prostaglandin F2α excretion, and acetylcholine-induced decrease in blood pressure improved in the V and I+V groups.
  
  
  CONCLUSIONS
  The data indicate that irbesartan effectively decreases blood pressure and renal AngII levels, and improves albuminuria. Our findings indicate that vitamin D enhances klotho expression, suppressing oxidative stress and albuminuria without substantial changes in renal AngII levels. These results suggest that the amelioration of endothelium function by vitamin D involves free klotho.
authors.affiliation: International University of Health and Welfare, Department of Medicine, Minato, Tokyo, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Takenaka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Inoue
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ohno
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Akira
authors.initials: A
authors.lastname: Nishiyama
authors.forename: Naohito
authors.initials: N
authors.lastname: Ishii
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology; D005966:Glucuronidase / Q000378:metabolism; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D000077405:Irbesartan; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D007674:Kidney Diseases / Q000209:etiology / Q000503:physiopathology*; D000090265:Klotho Proteins; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011918:Rats, Inbred SHR; D013777:Tetrazoles / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014815:Vitamins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D001713:Biphenyl Compounds; D013777:Tetrazoles; D014815:Vitamins; D000804:Angiotensin II; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D005966:Glucuronidase; D000090265:Klotho Proteins; D002117:Calcitriol; D000077405:Irbesartan