Prevalence of Chlamydia pneumoniae Infection in Atherosclerotic Plaques of Corpses Referred to Iranian Legal Medicine Organization, Tehran

Abstract

Introduction: Microbes such as Chlamydia pneumoniae play an important role in development of atherosclerosis. The bacterium invades vessels walls, directly or indirectly, and by releasing endotoxins or lipopolysaccharides into the bloodstream leads to injuries to endothelial cells. Aim: To determine the prevalence of C. pneumoniae in atherosclerotic plaques of corpses, by PCR (Polymerase Chain Reaction) and to examine the correlation between clinical status and presence of this bacterium in Iran. Materials and Methods: In this descriptive comparative study, a total of 118 samples, including 59 from corpses with atherosclerotic plaques in arteries (44 coronary and 15 abdominal aorta samples) and 59 from corpses without atherosclerotic plaques or obstruct in arteries (44 coronary and 15 abdominal aorta samples) were refrigerated at -70°C. Then, DNA was extracted and to detect C. pneumoniae, the pstI gene was selected and after amplification, samples were electrophoresed to confirm the presence of expected PCR products. The data were analysed using Chi-square statistical test and p-value less than 0.05 was considered to be statistically significant. Also, the relation between C. pneumoniae and some variables of atherosclerotic diseases such as hypertension, hyperlipidemia, smoking and diabetes were studied. Results: In this study, 15% (9/59) of samples from corpses with atherosclerotic plaque were positive for C. pneumoniae DNA, 11% (7/59) in coronary arteries and 4% (2/59) in aortic wall layer while, there was no evidence of C. pneumoniae in corpses with no plaque or obstruction in arteries. Variables such as hypertension, hyperlipidemia and myocardial infarction had higher values in C. pneumoniae positive samples; however, there was no statistically significant difference (p> 0.52). Conclusion: Presence of C. pneumoniae in atherosclerotic plaques and absence in healthy vessels, confirm the possible role of C. pneumoniae in development of atherosclerosis, especially in regions with frequent infections. Nevertheless, the exact mechanism explaining the high prevalence of atherosclerotic vascular disease is completely unknown.

Keywords

• abdominal aorta
• atherogenesis
• hyperlipidemia
• myocardial infarctions
• psti gene