A low-calorie diet improves endothelium-dependent vasodilation in obese patients with essential hypertension.
BACKGROUND
Both obesity and hypertension are associated with endothelial dysfunction. The purpose of this study was to investigate the effects of a low-calorie diet on endothelial function in obese patients with essential hypertension.


METHODS
We measured forearm blood flow (FBF) during intra-arterial infusion of acetylcholine (ACh; 7.5, 15, 30 microg/min), an index of endothelium-dependent vasodilation, and isosorbide dinitrate (ISDN; 0.75, 1.5, 3.0 microg/min), an index of endothelium-independent vasodilation, in obese patients with essential hypertension before and after 2 weeks on a low-calorie diet (800 kcal/d). The study included 11 obese hypertensive Japanese patients (mean body mass index, 30.8 +/- 3.6 kg/m2). Fifteen healthy Japanese normotensive individuals were recruited as a control group.


RESULTS
In obese patients with hypertension, the response of FBF to ACh was attenuated compared to healthy individuals (P < .001). Caloric restriction reduced body weight from 77.5 +/- 15.0 to 73.2 +/- 13.5 kg (P < .01), the mean blood pressure from 118.4 +/- 8.7 to 105.7 +/- 8.5 mm Hg (P < .01), fasting plasma insulin from 85.8 +/- 22.8 to 64.8 +/- 27.0 pmol/L (P < .05), serum total cholesterol from 5.30 +/- 0.76 to 4.67 +/- 0.58 mmol/L (P < .05), and low density lipoprotein cholesterol from 3.80 +/- 0.48 to 3.29 +/- 0.44 mmol/L (P < .05). Basal FBF was similar before and after weight reduction. Caloric restriction enhanced the response of FBF to ACh (P < .05), but did not alter the response to ISDN. The intra-arterial infusion of NG-monomethyl-L-arginine (8 micromol/min), a nitric oxide synthase inhibitor, decreased the enhanced ACh-induced blood flow response induced by caloric restriction.


CONCLUSIONS
The present findings suggest that the caloric restriction improves endothelial-dependent vasodilation through an increased release of nitric oxide in obese hypertensive patients.
Sasaki
Shota
S
First Department of Internal Medicine, Hiroshima University, Faculty of Medicine, Japan.
Higashi
Yukihito
Y
Nakagawa
Keigo
K
Kimura
Masashi
M
Noma
Kensuke
K
Sasaki
Satoshi
S
Hara
Keiko
K
Matsuura
Hideo
H
Goto
Chikara
C
Oshima
Tetsuya
T
Chayama
Kazuaki
K
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D008078:Cholesterol, LDL / Q000097:blood; D004730:Endothelium, Vascular / Q000502:physiology*; D002149:Energy Intake; D005260:Female; D005542:Forearm / Q000098:blood supply; D006801:Humans; D006937:Hypercholesterolemia / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D009765:Obesity / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation; D019323:omega-N-Methylarginine / Q000494:pharmacology
D008078:Cholesterol, LDL; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D000109:Acetylcholine