齲歯・歯周病と脳卒中・認知症の関連（RAMESSES研究）

抄録

Hypertensive intracerebral hemorrhage (ICH) is caused by fibrinoid necrosis and vascular failure as a result of hypertension–associated pathological changes in small arteries, accounting for about 80% of all ICH. In the developed countries, as a result of the enlightenment for the general public through education, the prevalence of low–salt diet and increase in the use of antihypertensive drugs have reduced frequency of ICH, but the incidence of ICH in Japan is still higher than in Western countries. In many epidemiological studies, the relationship of stroke with oral diseases such as dental caries and periodontal disease, so–called “brain-oral association”, has been reported. In both basic and cross–sectional epidemiological studies, Streptococcus mutans harboring cnm gene encoding the collagen–binding protein Cnm has been linked with hypertensive ICH. The Cnm–positive Streptococcus mutans is presumed to attach to exposed collagen in areas of disrupted blood–brain barrier, induce inflammation, block platelet accumulation, and subsequently induce microbleeds and ICH. Endothelial damage due to shear stress, oxidative injury, or other causes may be a prerequisite for the collagen exposure and attachment of Cnm–positive S. mutans to collagen. To prospectively determine the link between the Cnm–expressing Streptococcus mutans and ICH, a longitudinal study named RAMESSES (Risk Assessment of cnM–positivE Streptococcus mutans in StrokE Survivors) study was started. Further elucidation of the clinical and pathological condition in which specific oral bacteria contribute to the development of vascular diseases including ICH is important for the establishment of new prevention and treatment strategies against cardiovascular diseases.