Detecção de bactérias orais e avaliação da expressão de marcadores inflamatórios e trombogênicos em valvas cardíacas sadias e na estenose aórtica calcificada

Abstract

The present study aimed to perform molecular, histomorphological and immunohistochemical analysis of oral pathogens in healthy cardiac valves and calcified aortic stenosis, as well as evaluate the expression of Osteopontin, Fibrinogen, CD61 and inflammatory markers in these samples. Dental plaque, saliva and heart valve samples from ten patients with calcified aortic stenosis were collected for molecular analysis of S. mutans, P. intermedia, P. gingivalis and T. Denticola, through real-time Polymerase Chain Reaction (PCR). In addition, heart valve tissue from five healthy young men submitted to necropsy was also collected and analyzed for the same bacteria using the same technique mentioned above. Fragments of all specimens were fixed in 10% buffered formalin for histomorphological (Hematoxylin/eosin), histochemical (Giemsa) and immunohistochemical (Streptavidin-biotin-peroxidase method) analysis for anti-Streptococcus mutans, anti-IL-1β, anti-TNF alpha, anti-COX -2, anti-NF-κB, anti-C-Reactive Protein, anti-Osteopontin, anti-Fibrinogen and anti-CD61. To evaluate caries and periodontal disease, the DMFT (decayed, missing and filled teeth) and PSR (periodontal screening and recording) indexes were used, respectively. Molecular analysis of supragingival and subgingival dental plaque and saliva of dentate and edentulous patients with calcified aortic stenosis revealed a high frequency of S. mutans and P. intermedia in the samples (varying between 90.0% and 100.0%), whereas the frequency of P. and T. denticola was lower (ranging from 10.0% to 67.0%). The evaluation of oral bacteria in valvar tissue by realtime PCR revealed a high frequency of S. mutans (80.0%) in healthy cardiac valves and in calcified aortic stenosis valves, while P. intermedia, P. gingivalis and T. Denticola were not identified. Immunohistochemical analysis identified S. mutans only in valves with calcified aortic stenosis (80%). Areas of calcification, fibrosis and myxoid degeneration were identified in 100% of the diseased cardiac valves, and they were all colonized with Streptococcus, which was revealed by histochemical analysis. The number of decayed, missing and filled teeth (DMFT) was 25.6 ± 6.7 in patients with valve disease. Positive immunohistochemical staining for IL-1β, TNF alpha, COX-2, fibrinogen, C-Reactive Protein and osteopontin was observed in 100% of the calcified aortic stenosis samples that were also immunopositive for S. mutans, whereas the immunoexpression of NF-kB and CD61 was evidenced in 87.5% and 62.5% of those samples, respectively. In healthy samples, the expression of these immunomarkers was negative. The detection of S. mutans in the calcified aortic stenosis through multiple techniques with different sensitivity may suggest the colonization of this bacterium in extraoral sites. In addition, the presence of S. mutans and the expression of 11 inflammatory and thrombogenic immunomarkers in microscopically altered areas was observed in the diseased valves, guiding a possible relation with the calcified aortic stenosis.