Department of Nutrition and Dietetics,Harokopio University,70 Eleftheriou Venizelou Avenue Kallithea,17671Athens,Greece.
Br J Nutr. 2019 May;121(9):982-991. doi: 10.1017/S0007114519000308. Epub 2019 Apr 3.
Platelet-activating factor (PAF) is a potent mediator of inflammation that plays a crucial role in atherosclerosis. The purpose of this study was to evaluate the effect of a dietary supplement containing mainly plant extracts on PAF actions and metabolism in healthy volunteers. A double-blind, placebo-controlled, 8 weeks' duration study was performed. Healthy volunteers were randomly allocated into the supplement or the placebo group and fifty-eight of them completed the study. The supplement contained plant extracts (Aloe gel, grape juice, Polygonum cuspidatum) and vitamins. The activities of PAF metabolic enzymes: the two isoforms of acetyl-CoA:lyso-PAF acetyltransferase, cytidine 5'-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-cholinephosphotransferase) and platelet-activating factor-acetylhydrolase (PAF-AH) in leucocytes and lipoprotein associated phospholipase-A2 in plasma were measured along with several markers of endothelial function. Platelet aggregation against PAF, ADP and thrombin receptor activating peptide was measured in human platelet-rich plasma by light transmission aggregometry. No difference was observed on soluble vascular cell adhesion molecule-1, sP-selectin and IL-6 levels at the beginning or during the study period between the two groups. Concerning PAF metabolism enzymes' activity, no difference was observed at baseline between the groups. PAF-AH activity was only increased in the supplement group at 4 and 8 weeks compared with baseline levels. In addition, supplement consumption led to lower platelet sensitivity against PAF and ADP compared with baseline levels. However, a trial effect was only observed when platelets were stimulated by PAF. In conclusion, supplementation with plant extracts and vitamins ameliorates platelet aggregation primarily against PAF and secondarily against ADP and affects PAF catabolism by enhancing PAF-acetylhydrolase activity in healthy subjects.
血小板活化因子（PAF）是一种强有力的炎症介质，在动脉粥样硬化中起着至关重要的作用。本研究旨在评估一种主要包含植物提取物的膳食补充剂对健康志愿者 PAF 作用和代谢的影响。进行了一项为期 8 周的双盲、安慰剂对照研究。健康志愿者被随机分配到补充剂或安慰剂组，其中 58 人完成了研究。补充剂包含植物提取物（芦荟凝胶、葡萄汁、虎杖）和维生素。白细胞中 PAF 代谢酶的活性：两种乙酰辅酶 A：溶血 PAF 乙酰转移酶同工型、胞苷 5'-二磷酸胆碱：1-烷基-2-乙酰-sn-甘油胆碱磷酸转移酶（PAF-胆碱磷酸转移酶）和血小板活化因子-乙酰水解酶（PAF-AH）以及脂蛋白相关磷脂酶 A2 在血浆中的活性，以及几种内皮功能标志物进行了测量。通过透光比浊法测量富含血小板的人血浆中血小板对 PAF、ADP 和凝血酶受体激活肽的聚集。在研究开始时或研究期间，两组之间可溶性血管细胞黏附分子-1、sP-选择素和 IL-6 水平无差异。在基线时，两组之间 PAF 代谢酶活性无差异。与基线水平相比，仅在 4 周和 8 周时补充组的 PAF-AH 活性增加。此外，与基线水平相比，补充剂消耗可降低血小板对 PAF 和 ADP 的敏感性。然而，仅当血小板被 PAF 刺激时才观察到试验效应。总之，植物提取物和维生素的补充可改善血小板聚集，主要针对 PAF，其次针对 ADP，并通过增强 PAF-乙酰水解酶活性来影响 PAF 的分解代谢。
