DEMONSTRATION OF CHLAMYDIA-PNEUMONIAE IN THE WALLS OF ABDOMINAL AORTIC-ANEURYSMS

Background: Seroepidemiologic studies have indicated an association be tween chronic Chlamydia pneumoniae infection and coronary heart diseas e. The organism, which is a common respiratory pathogen, has been demo nstrated in atherosclerotic lesions of the aorta and coronary arteries . Abdominal aortic aneurysms are frequently associated with atheroscle rosis, and inflammation may actually be an important factor in aneurys mal dilatation. Hence it could be assumed that C. pneumoniae may play a role in maintaining an inflammation and triggering the development o f aortic aneurysms. Methods and Results: Specimens from abdominal aort ic aneurysm were examined for the presence of C. pneumoniae by immunoh istochemical analysis, the polymerase chain reaction amplifying omp1 g ene, transmission electron microscopy, and culture methods with histol ogically atherosclerosis-negative human aortic tissues used as a contr ol group. Chlamydial lipopolysaccharide and C. pneumoniae specific ant igens were found by immunohistochemistry in 12 and 8 of 12 aneurysm sp ecimens, respectively, and C. pneumoniae DNA could be demonstrated in 6 of 6 aneurysm specimens studied. Furthermore electron microscopy rev ealed the presence of Chlamydia-like elementary bodies in three of fou r aneurysm specimens tested. None of the control samples gave positive reaction in the polymerase chain reaction, and C. pneumoniae antigens were not detected in any of them. Conclusions: C. pneumoniae is frequ ently found in the vessel wall of abdominal aortic aneurysm. The poten tial etiopathogenetic role of C. pneumoniae in the development of thes e aneurysms remains to be studied.