engleski

The role of cyclooxygenase in the mechanisms of vascular reactivity in the skin microcirculation of young healthy individuals

Introduction: Various metabolites, e.g. NO and metabolites of arachidonic acid mediate endothelium-dependent vasodilation in microcirculation, as shown in animal models and in humans. Previously, we demonstrated that consumption of functional food enriched in n-3 polyunsaturated fatty acids (n-3 PUFAs) enhances microvascular reactivity stimuli, but the underlying mechanims is still not known. Aim: Present study aimed to evaluate effects of consumption of hen eggs enriched with four nutrients on microvascular reactivity in healthy young persons. Furthermore, the role of cyclooxygenases (COX-1 and COX-2) in these responses was assessed. Materials and methods: Study was randomized, double-blind, and placebo- controlled. Subjects were divided into a control group (N=6), who consumed regular hen eggs, and Nutri4 group (N=5), who consumed eggs enriched with n-3 PUFAs, selenium, vitamin E and lutein. Subjects consumed three boiled eggs per day during 3 weeks. To assess microvascular reactivity to acetylcholine and reactive hyperemia in forearm skin microcirculation laser Doppler flowmetry was performed before and after dietary protocol. Separately, in subjects who completed dietary protocols, measurements were performed before and after peroral administration of 100 mg of indomethacin (non-selective inhibitor of COX 1 and COX 2 enzymes). Plasma concentration of free fatty acids was measured, too. Results: Following Nutri4 eggs consumption, n-3 PUFAs concentration in plasma was significantly increased compared to control values. While acetylcholine-induced dilatation was similar before and after particular dietary protocols or between Nutri4 and control groups, significantly enhanced microvascular blood flow was observed in response to reactive hyperemia in the Nutri4 group after completion of dietary protocol, compared to control values. This enhanced response in reactive hyperemic blood flow was siignificantly attenuated by indomethacin in Nutri4 group. Conclusion: The results suggest a positive effect of consumption of eggs enriched with n-3 PUFAs, selenium, lutein and vitamin E on the microvascular reactivity of healthy young subjects. Furthermore, results suggest involvement of metabolites of the cyclooxygenases degradation pathway of n-3 PUFAs in response to reactive hyperemia.

cyclooxygenase ; endothelial function ; fatty acids, n-3 PUFAs ; lutein ; selenium ; vitamin E ; vascular reactivity

Acknowledgements: The study was funded by European Structural and Investment Funds to Scientific Centre of Excellence for Personalized Health Care, the Josip Juraj Strossmayer University of Osijek, Scientific Unit for Research, Production and Medical Testing of Functional Food, # KK.01.1.1.01.0010.