engleski

Role of constrictor prostaglandins in high salt diet-induced microvascular dysfunction in humans

Objective: To assess the regulation of microvascular reactivity and to elucidate the role of cyclooxygenases and angiotensin type 1 (AT1) receptors in normotensive subjects on a short-term high salt or low salt diet. Methods: 42 healthy female subjects participated in study. All participants maintained specific low salt diet (intake <40 mmol Na/day) through 7 days and simultaneously were divided in two groups: high salt diet (HSD) group (intake of salt supplement, 200 mmol Na/day) and low salt diet (LSD) group (intake of placebo supplement, 0 mmol Na/day). Microvascular reactivity was assessed by laser Doppler flowmetry (LDF) with and without the nonspecific cyclooxygenase inhibitor indomethacin (100 mg once per os), administered to participants of both groups 90 minutes before repeated LDF measurement. To test the role of the AT1 receptors in modulating microvascular reactivity, the AT1 receptor antagonist losartan (50 mg/day) was given to the LSD group during the protocol. Results: LDF measurements in the HSD group showed a significant impairment in tissue blood flow following release of a 1 min occlusion compared to the control values. Indomethacin restored postocclusion blood flow to control values in HSD group. One week of losartan administration did not affect post-occlusion tissue blood flow in LSD group. Conclusions: The present study shows that 1 week of HSD causes impaired recovery of post-occlusion tissue blood flow that was restored by indomethacin. These observations suggest that a vasoconstrictor metabolite of cyclooxygenases could play role in impaired tissue blood flow in subjects taking HSD.

high salt diet; endothelium; cyclooxygenases; Laser Doppler flowmetry

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