Calcitriol supplementation improves endothelium-dependent vasodilation in rat hypertensive renal injury.

Abstract

BACKGROUND/AIMS:

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: Tsuneo Takenaka, Tsutomu Inoue, Yoichi Ohno, Takashi Miyazaki, Akira Nishiyama, Naohito Ishii, Hiromichi Suzuki
• Journal: Kidney & blood pressure research (Kidney Blood Press Res) Vol. 39 Issue 1 Pg. 17-27 ( 2014) ISSN: 1423-0143 [Electronic] Switzerland
• PMID: 24821359 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 S. Karger AG, Basel.

Chemical References

• Antihypertensive Agents
• Biphenyl Compounds
• Tetrazoles
• Vitamins
• Angiotensin II
• 8-epi-prostaglandin F2alpha
• Dinoprost
• Glucuronidase
• Klotho Proteins
• Calcitriol
• Irbesartan

Topics

• Angiotensin II (metabolism)
• Animals
• Antihypertensive Agents (pharmacology)
• Biphenyl Compounds (pharmacology)
• Blood Pressure (drug effects, physiology)
• Calcitriol (administration & dosage, pharmacology)
• Dietary Supplements
• Dinoprost (analogs & derivatives, metabolism)
• Disease Models, Animal
• Endothelium, Vascular (drug effects, physiopathology)
• Glucuronidase (metabolism)
• Hypertension (complications, physiopathology)
• Irbesartan
• Kidney (drug effects, metabolism)
• Kidney Diseases (etiology, physiopathology)
• Klotho Proteins
• Male
• Oxidative Stress (drug effects, physiology)
• Rats
• Rats, Inbred SHR
• Tetrazoles (pharmacology)
• Vasodilation (drug effects, physiology)
• Vitamins (administration & dosage, pharmacology)