The prevalence of Chlamydia pneumoniae in the aortic wall and in peripheral blood of patients scheduled for coronary artery bypass grafting

Some reports confirm a potential role of Chlamydia pneumoniae (ChP) in atherogenesis. In order to explore possible association between ChP and atherosclerosis, investigations were carried out in which the frequency of ChP in the arterial wall and peripheral blood was assessed in a group of patients with chronic coronary artery disease (CAD). Fifty-seven patients were enrolled in the study, 13 women and 44 men aged 61.8±6.5 (47-74), with previously diagnosed CAD, scheduled for planned coronary artery bypass grafting due to clinical indications. Vessel specimens retrieved from the ascending aorta (as a part of routine proximal venous graft development procedure) and peripheral blood mononuclear cells (PBMCs) from venous blood were evaluated for the presence of ChP DNA. Genomic DNA was extracted from PBMCs and vessel specimens. Quantitative real-time polymerase chain reaction (qPCR) was performed to detect ChP DNA. A statistically more frequent occurrence of ChP was observed in aortic tissues compared to blood samples (70.2% vs 56.1%, respectively). Similarly, the number of ChP DNA genomic copies [n/1μg genomic DNA] was significantly higher in tissue specimens compared to blood samples (89±91 vs 41±77, respectively; p=0.0046). In patients without ChP in blood specimens, we observed significantly higher amounts of ChP in tissue specimens compared to patients with ChP in blood specimens (156±71 vs 107±88, respectively; p=0.0453). No correlation was found between the number of ChP DNA copies [n/1μg genomic DNA] in blood and in aortic specimens. The infection of ChP in the aortic wall was connected with hypercholesterolemia (p=0.029) and diabetes (p=0.03). We conclude that Chlamydia pneumoniae is a pathogen frequently occurring in the aortic wall of patients with CAD. The occurrence of ChP DNA in the aortic tissue is related to classic CAD risk factors such as diabetes and dyslipidemia.

Inflammatory components in endarterectomy lesions: an immunohistological study

The aim of this study was to characterize the immunohistological components of chronic inflammation in endarterectomy lesions. Therefore, in 24 patients endarterectomy specimens were obtained from coronary arteries during CABG surgery (16 from RCA and 8 from LCA) and immunohistologically analyzed using avidin-biotin method (LSAB(R)/AP) with monoclonal antibodies. Macrophages and CD3 lymphocytes were counted under 200x magnification but MHC class II and ICAM-1 adhesion molecules were analyzed semi-quantitatively (scale from 0 to 3+). The mean macrophages density was 47.8+/-9.8 cells per mm2 and mean CD3 lymphocyte density was 1.3+/-0.6 cells per mm2. Lack or weak expression of HLA-DR (0-1+) on macrophages was found in 17 of 24 cases (70.8%). In the remaining seven cases (29.2%) there was a moderate and strong expression (2+ and 3+) of HLA-DR antigens. Similarly, no or weak ICAM-1 expression on macrophages was detected in 19 cases (79.2%). These cells were positively stained for ICAM-1 in only five cases (20.8%). Our data suggest that in advanced primary atherosclerotic lesions chronic inflammation is still present. On the other hand, the small number of activated inflammatory cells and the absence of positively stained endothelium suggests that inflammatory process tends to be burnt-out.