Relationship of Streptococcus mutans with valvar cardiac tissue: A molecular and immunohistochemical study.

Abstract

The present study aimed to investigate the presence or absence of Streptococcus mutans in oral cavity and valvular samples associating with the histomorphologic alterations of calcified aortic stenosis. Dental plaque and cardiac valve samples were collected from 10 patients with calcified aortic stenosis for molecular analysis of Smutans by real-time polymerase chain reaction (PCR). Healthy valve tissue was also collected from five young cadavers and analyzed for Smutans. Moreover, fragments of all valvar specimens were submitted for histomorphological analysis and immunohistochemistry (anti-Smutans and anti-CD61). Streptococcus mutans was present in 100% of the oral cavity samples from the patients with calcified aortic stenosis in the molecular analysis. The analysis by real-time PCR showed that Smutans presented the same proportion in healthy valves and those with calcified aortic stenosis (80%; P=1.000). Conversely, the immunoexpression of Smutans was 37.40 (IC95%=1.49-937.00) times superior in samples of patients with cardiac disease (P=.007). The immunoexpression analysis showed that CD61 was present in seven (70%) calcified aortic stenosis samples, all of which were also immunopositive for Smutans. Streptococcus mutans was found in the oral cavity, healthy valve tissue, and calcified aortic stenosis samples. However, the microorganism was visualized by immunohistochemistry only in the calcified aortic stenosis samples, which may suggest viability and an increased bacterial density in this condition. The association of the presence of Smutans and positive CD61 immunoexpression suggests a probable relationship with calcified aortic stenosis.