Investigation of the relationship between chlamydia pneumoniae and atherosclerosis by 16S rRNA sequencing method

Cardiovascular and cerebrovascular diseases are a major public health problem globally, with high morbidity and mortality rates. Atherosclerosis has been blamed for half of the adult deaths in the Western world, especially in the United States. Stenosis, ischemic heart disease due to atherosclerosis of coronary vessels, and cardiac syndromes are among the causes of sudden death due to arterial thrombus formation. The theory that atherosclerosis, which is associated with many reasons such as dietary habits and smoking, which is one of the genetically related vascular wall anomalies, has been increasingly supported since the late 19th century, as a result of chronic inflammation that develops due to chronic infections. After Saikku showed C. pneumoniae inclusions in the post-mortem atheroma plaque samples of patients who died of cardiovascular diseases with electron microscopy studies. After Saiku published the results of his study, numerous studies were conducted questioning the relationship between C. pneumoniae atherosclerosis. In these studies, different methods such as electron microscopy and direct fluorescent antibody or enzyme immunoassay method were used from endarterectomy samples during post-mortem or cardiovascular surgery. At the end of all these studies, the previously accepted hypothesis of "atherosclerosis develops as a result of infection of the vessel wall" turned into "atherosclerosis develops as a result of infection of the vessel wall and monocytes with C. pneumoniae". Later, the results of studies claiming that the frequency and duration of double and triple endpoints were found to be significantly different in the groups in which antibiotics to which C. pneumoniae were susceptible were added to the treatment in patients with acute myocardial infarction compared to the control groups began to be published. On the other hand, some researchers claimed that it can cause atherosclerosis in H. pylori, CMV, adenovirus, and herpes group viruses using PCR-based methods. But they could not show the microorganism itself directly in the plate, foam cell. As a result, it is highly probable; C. pneumoniae may be the cause of the sclerotic lesion and atherosclerotic plaques can be seen in all arteries including cerebrovascular arteries except for the internal mammary artery. With this study, we aimed to show the possible relationship between atherosclerosis and especially C. pneumoniae and H. pylori by using PCR-sequencing and IFAT methods. Most of the routine operations could not be performed as a result of the outbreak of the covid-19 pandemic during the sample collection process of the project. For this reason, we could not reach the number of patient samples we planned, but we thought that the results of the 11 samples we evaluated in our study could be a guide for further studies with larger case groups. At the end of the study, 8 (72.7 %) of our patient group with a mean age of 58 years had anti-C. pneumuniae antibody response > 1/16 with IFAT, while 7 (63.6 %) of these patients had C. pneumoniae in the atheroma plaques. Target sequences of H.pylori ureC gene were found in 1 (9.1 %) sample in atheroma plaques. As in previous studies, the incidence of C. pneumoniae in atheroma plaques was accepted as a possible association.