A study to elucidate the mechanism of intracerebral heorrhage induced by collagen-binding Streptococcus mutans and to develop a novel preventive therapy

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22610
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 52:General internal medicine and related fields
• Research Institution: National Cardiovascular Center Research Institute
• Principal Investigator: Ihara Masafumi 国立研究開発法人国立循環器病研究センター, 病院, 部長 (00372590)
• Co-Investigator(Kenkyū-buntansha): 仲野 和彦 大阪大学, 歯学研究科, 教授 (00379083)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 脳内出血 / ミュータンス菌 / 脳微小出血 / コラーゲン

Outline of Final Research Achievements

We retrospectively investigated patients with stroke receiving oral microbiological examination and head 3T magnetic resonance imaging evaluations twice in the period 2014 to 2019, allowing >180-day interval.
A total of 111 patients were identified; 21 (19%) with cnm-positive S. mutans and 90 (81%) without. Clinical history, including blood pressure and the use of antithrombotic agents, were comparable between the 2 groups. New CMB were more commonly observed in patients with cnm-positive S. mutans (52% versus 23%; P=0.008). The incidence of CMB was significantly higher in the group with cnm-positive S. mutans, especially in deep areas, (incidence rate ratios [95% CI], 5.1 [1.9-13.6] for CMB in any brain region; 15.0 [5.4-42.0] for deep CMB), which persisted after adjusting for age, sex, hypertension, and renal impairment (4.7 [1.8-11.9] for CMB in any brain region; 13.9 [4.3-44.5] for deep CMB).

Free Research Field

脳神経内科

Academic Significance and Societal Importance of the Research Achievements

今回、cnm陽性ミュータンス菌と脳出血との関係を明らかにできたことから、脳卒中の機序の解明に寄与するものと考えられる。現在、cnm陽性ミュータンス菌によって脳出血が引き起こされるメカニズムを探索する基礎研究や、国内15施設と協力して進めている多施設前向き研究、アフリカ、東南アジアを含む世界中の他人種・地域における本菌の役割を検討する国際共同観察研究を実施している。我が国では欧米諸国と比べてまだまだ脳出血が多く、口腔内の悪玉むし歯菌を減らすために、口腔内環境を整えることが有効であると考えられる。