Molecular detection of bacterial RNA in atheromatous plaques of patients with stroke

Aim: Infections and chronic inflammatory conditions such as periodontitis, have been associated with the development and progression of atherosclerosic process and susceptibility to plaque rupture. The chronicity of periodontal disease provides a rich source of subgingival bacteria, mostly gram negative, which are frequently spread in the blood as a result of the periodontal lesion. DNA from periodontal pathogens has been detected in atherosclerotic lesions, but viable bacteria have not yet been isolated. This study was carried out to detect, by molecular techniques, the presence of RNA of bacteria in atheromatous plaques collected from both symptomatic and asymptomatic carotid stenosis patients. Methods: Total RNA extracts, derived from eighty-one atheromatous plaques collected during carotid endartrectomy (36 from symptomatic patients and 45 from asymptomatic patients) underwent reverse transcription to cDNA using random primers. All cDNA samples obtained were tested by PCR using universal primers for global bacterial detection (16S rRNA). Results: Of eighty-one sample tested, seven were found positive (8.6%), six out of the thirty-six (16.6%) of symptomatic patients and only one out forty-five (2.2%) from the asymptomatic patients group. Conclusion: This pilot study suggests the preferential presence of bacterial RNA in recently symptomatic atherosclerotic plaques. These results are of interest because the presence of viable bacteria may be presumed into the atheromatous plaques and, therefore, indicates a possible bacterial role in activation of several inflammatory factors and in atherosclerotic plaque vulnerability.