BACKGROUND: The inflammatory process has an essential impact on the developmentof atherosclerosis. Three mechanisms are mentioned: 1) possibility of direct development of Chlamydiainfection in the vicinity of the blood vessel wall; 2) impact of persistent or recurrrent Chlamydia infectionon the increased blood concentration of risk factors for atherosclerosis; 3) an autoimmunological reaction.MATERIAL/METHODS: Electron microscope examinations were performed on specimens from atherosclerotic lesionsof the interior cervical arteries, collected from patients who had undergone endarterectomy. The materialcame from 8 patients (age from 58 to 72). The specimens were fixed for electron microscopy, and afterdehydration were immersed in Spurr resin. Ultrathin slices were examined under a transmission electronmicroscope. RESULTS: In the successive tested layers nearest the lumen of the vessel we found erythrocyticelements, fibrin, and lipid membranes. In deeper layers there were lymphocytic cells, monocytes, andmacrophages loaded with phagocyted lipid material. Under this layer we found in some specimens a coatingwhich had undergone mineralization: calcium structures and cholesterol were overlaid on a proteoglycanatebase. Smooth muscles cells had undergone the heaviest proliferation among the cells on artery wall. Inthe tested material we detected diversified morphological forms of Chlamydia sp. Particular attentionshould be drawn to the appearance of very young vessel forms, which suggests a process of angiogenesisin the atherosclerotic plaques. CONCLUSIONS: We found that one of the pathogens that may lead to atheroscleroticlesions is Chlamydia sp. The process of atherogenesis in cervical arteries is accompanied by angiogeneticprocesses.

Keywords: Arteries, Arteriosclerosis, Chlamydia, Erythrocytes, Microscopy, Electron, Neovascularization, Physiologic