Department of Surgery, Division of Vascular Surgery, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan.
Thromb Res. 2011 May;127(5):418-25. doi: 10.1016/j.thromres.2010.12.004. Epub 2011 Feb 18.
More and more evidence show that periodontal anaerobes contribute to pathogenesis of peripheral artery diseases. As a typical oral anaerobe that results in periodontitis, P.gingivalis aggregates platelets in PRP in vitro and participated in artery thrombosis. However, in vivo effect on platelet activation and aggregation remains unclear. This study aimed to clarify its role on platelets activation on more physiological environment, that is, on whole blood and systemic circulation.
To fully estimate platelet activation, CD62P(P-selectin) expression on platelet surface and fibrinogen binding of platelet via conjugated glycoprotein GPIIb/IIIa in whole blood were assayed by flow cytometry, and platelet aggregation was measured on an impedance aggregometor. As primary study, platelet reactivity was assessed after in vitro rat whole blood incubation with P.gingivalis strain 381 in tubes, followed or not followed by ADP and arachidonic acid stimulation. In addition, PBS solution of P.gingivalis was infused into rat to produce transient bacteremia model for 5 minutes and blood samples were subjected to analysis for platelet activation in vivo.
P.gingivalis could not induce rat platelet aggregation in whole blood in vitro, but increased aggregation when irritated by collagen stimulation. Flow cytometric study showed that incubation with P.gingivalis increased CD62P expression and fibrinogen binding of platelet. Moreover, further stress by 10 μmol/L ADP and 260 mmlol/L arachidonic acid yielded additional expression. As in vivo study, after P.gingivalis solution challenged, rat platelet aggregability was enhanced, and CD62P positive percentage of platelets and further reactivity to ADP stimulation improved.
In whole blood and in systemic circulation, P.gingivalis could induce rat platelet activation and increase aggregability transiently. The results helped to understand the mechanism underlining which P.gingivalis promoted arteriosclerosis and thrombo-embolic disorders. Further study about chronic infection with P.gingivalis on platelet activity is expected.
越来越多的证据表明，牙周厌氧菌有助于外周动脉疾病的发病机制。作为导致牙周炎的典型口腔厌氧菌，牙龈卟啉单胞菌在 PRP 中聚集血小板，并参与动脉血栓形成。然而，其在体内对血小板激活和聚集的影响尚不清楚。本研究旨在在更生理的环境下，即全血和全身循环中，阐明其对血小板激活的作用。
为了充分评估血小板的激活，通过流式细胞术检测全血中血小板表面 CD62P（P-选择素）的表达和血小板与糖蛋白 IIb/IIIa 结合的纤维蛋白原，通过阻抗凝集仪测量血小板聚集。作为初步研究，在试管中用牙龈卟啉单胞菌 381 株体外孵育大鼠全血后，评估血小板反应性，然后或不进行 ADP 和花生四烯酸刺激。此外，将牙龈卟啉单胞菌的 PBS 溶液注入大鼠体内，产生短暂的菌血症模型 5 分钟，然后对体内血小板激活进行血液样本分析。
牙龈卟啉单胞菌不能在体外全血中诱导大鼠血小板聚集，但在胶原刺激下可增加聚集。流式细胞术研究表明，牙龈卟啉单胞菌孵育可增加血小板 CD62P 的表达和纤维蛋白原的结合。此外，用 10μmol/L ADP 和 260mmol/L 花生四烯酸进一步刺激可产生额外的表达。作为体内研究，牙龈卟啉单胞菌溶液刺激后，大鼠血小板聚集性增强，血小板 CD62P 阳性率增加，对 ADP 刺激的反应性进一步增强。
在全血和全身循环中，牙龈卟啉单胞菌可诱导大鼠血小板短暂激活并增加聚集性。这些结果有助于理解牙龈卟啉单胞菌促进动脉粥样硬化和血栓栓塞性疾病的潜在机制。预计将进一步研究慢性感染牙龈卟啉单胞菌对血小板活性的影响。
