Detection of Chlamydia pneumoniae and Helicobacter pylori DNA in human atherosclerotic plaques by PCR

Chlamydia pneumoniae and Helicobacter pylori can cause persistent infection s of the respiratory and gastrointestinal tract, respectively. It has been suggested that persistent infection of arteries with these bacteria can con tribute to the development of atherosclerosis, The aims of this study were to determine the presence of C. pneumoniae and H. pylori DNA in atheroscler otic plaque samples by PCR and to evaluate the correlation between clinical status and DNA positivity of these bacteria. Eighty-five consecutive patie nts (mean age, 59 +/- 10; 75 male, 10 female) undergoing coronary artery by pass grafting, carotid endarterectomy, and surgery of the abdominal aorta f or atherosclerotic obstructive lesions were included in the study. Forty-si x endarterectomy specimens from the atherosclerotic lesions and 39 specimen s from healthy regions of the ascending aorta, which were accepted as the c ontrol group, were excised. The presence of microorganism DNA in endarterec tomy specimens was assessed by PCR, C. pneumoniae DNA was found in 12 (26%) of 46 endarterectomy specimens and none of the healthy vascular-wall speci mens (P < 0.001), while H. pylori DNA was found in 17 (37%) of 46 endartere ctomy specimens and none of the controls (P < 0.001). Either C. pneumoniae or H. pylori DNA was positive in 23 (50%) of 46 patients and none of the co ntrols (P < 0.001), Six of the atherosclerotic lesions showed coexistence o f both of the microorganism DNAs, The presence of C. pneumoniae and H. pylo ri DNA in a considerable number of atherosclerotic plaques but their absenc e in healthy vascular wall supports the idea that they may have a role in t he development of atherosclerosis, especially in countries where infection is prevalent and where conventional risk factors fail to explain the high p revalence of atherosclerotic vascular disease.