title: The periodontal anaerobe Porphyromonas gingivalis induced platelet activation and increased aggregation in whole blood by rat model.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kang-min
authors.initials: KM
authors.lastname: Yu
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Inoue
authors.forename: Makoto
authors.initials: M
authors.lastname: Umeda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Terasaki
authors.forename: Zhi-yong
authors.initials: ZY
authors.lastname: Chen
authors.forename: Takehisa
authors.initials: T
authors.lastname: Iwai
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000382:microbiology*; D004195:Disease Models, Animal; D005340:Fibrinogen / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D019007:P-Selectin / Q000096:biosynthesis / Q000097:blood; D010518:Periodontitis / Q000097:blood* / Q000382:microbiology; D015539:Platelet Activation / Q000187:drug effects / Q000502:physiology; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D019007:P-Selectin; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D005340:Fibrinogen