Oral presentations O7.1 Pleiotropic actions of plant polyphenols in maintaining normal function of the vascular endothelium

Vascular endothelium dysfunction is the basic cause of development of cardiovascular disorders and is charac-terised by bioactive NO deficiency. Oxidative stress induced by the generally known atherosclerosis risk factors such as smoking, hypercholesterolaemia, hypertension, diabetes etc. was found to contribute to low bioavailabil-ity of NO. The present investigations indicate that polyphenols may exert a protective effect on vascular endothelium not only through scavenging oxygen free radicals but also through their direct effect on the system of NADPH oxidases, xan-thine oxidases and myeloperoxidase. The mechanism of this process is a direct action of polyphenols on the cellular NF-KB transcription factor. Polyphenols, and in particular catechins and anthocyanes, may also contribute in this mechanism to the inhibition of cyclooxygenase-2 (COX-2) activity. It is suggested that polyphenols may actively counteract apoptosis of endothelial cells through activation of the signalling pathway with participation of Src-ERK1/2 and inhibition of bax protein expression and caspase-3 inhibition. Polyphenols are also able to activate eNOS, contributing to an increase in the intracellular level of Ca++ and activation of phosphatidylinositol kinase (PI 3-K), which in turn leads to eNOS phosphorylation. Recently it has been shown that polyphenols may inhibit the activity of metalloproteinase and prevent in this way atherosclerotic plaque rupture, the consequences of which are acute coronary events. An important element of endothelial protection is inhibition of platelet adhesion and aggregation. Polyphenols inhibiting phospholipase C activity may exert an indirect effect on release of arachidonic acid which is the substrate for the synthesis of pro-aggregative thromboxane. Indeed, as it was proven in in vivo studies in animals and humans, resveratrol, a polyphenol originating from grapes, is a potent inhibitor of platelet aggre-gation caused by thrombin and cathepsin S. As we found in our clinical studies, polyphenols isolated from chokeberry fruit not only significantly lower systo-lic and diastolic blood pressure but also reduce inflammation associated with ischaemic heart disease. In summary, the biological effects of pleiotropic actions of polyphenols indicate their usefulness in atherosclerosis prevention. Nutrition is a factor of major importance for human health. Nowadays there is no doubts that interactions between genes and nutrients play a key role in health risk prediction and disease prevention. Individual nutritional status is determined not only by food availability, but also by genes that control food intake, nutrient absorption and metabolism. Nutrients can significantly influence gene expression and metabolic processes. Several gene loci have been shown to have a significant impact …