Detection of Chlamydia pneumoniae but not Helicobacter pylori in atherosclerotic plaques of aortic aneurysms

Abstract

Recent reports suggest an association between Chlamydia pneumoniae and Helicobacter pylori bacteria and atherosclerosis. We studied 51 patients (mean age, 68.3 years) who underwent abdominal aortic aneurysm surgery. For each patient we performed a microimmunofluorescence test for immunoglobulin G (IgG), IgA, and IgM antibodies to C. pneumoniae specific antigen (TW-183). Anti-H. pylori antibodies were determined by means of an EIA-G test. Each aortic aneurysm surgical specimen was sampled into multiple sections of 0.3 cm 2 each and frozen at ؊20؇C. Two samples of each aneurysm were used for a nested PCR with two sets of C. pneumoniae and two sets of H. pylori specific primers. Specimens were treated with a solution containing 20 mM Tris-HCl, Tween 20-Nonidet P-40 (0.5% [vol/vol] each), and 100 g of proteinase K per ml and incubated at 60؇C for 1 h and at 98؇C for 10 min. DNA was extracted twice with phenol-chloroform-isoamylic alcohol and precipitated with sodium acetate-ethanol by standard methods. Forty-one patients were seropositive for C. pneumoniae with past-infection patterns in 32 patients (16 < IgG < 512; 32 < IgA < 256) and high antibody titers in 9 patients (IgG > 512). In 26 of 51 patients, C. pneumoniae DNA was detected in aortic aneurysm plaque specimens. Of these patients, 23 had a serologic past-infection pattern, 2 had an acute reinfection pattern, and 1 was seronegative. Forty-seven of 51 patients were seropositive for H. pylori. In all cases PCR showed no evidence of H. pylori presence in plaque specimens. This study provides data on a possible C. pneumoniae involvement in the pathogenesis of aortic aneurysm and additional evidence for an association between this agent and atherosclerosis. Conversely, notwithstanding a high H. pylori seroprevalence observed, our results tend to rule out the possibility of a direct involvement of H. pylori in atherosclerosis.

Chlamydia pneumoniae reactive T lymphocytes in the walls of abdominal aortic aneurysms

“…1a and b. In C. pneumoniae immunostaining, 55% [6,11] of the specimens showed a positive reaction (Fig. 2).…”

Chlamydia pneumoniaeand atherosclerosis

“…This study examined excised hearts from individuals undergoing heart transplants. Three separate laboratories successfully cultured C. pneumoniae from one patient's coronary artery, and other investigators (Blasi et al ., 1996;Muhlestein et al ., 1996;Ong et al ., 1996) have isolated C. pneumoniae from atheromas. However, successful isolation and propagation of the organism from atherosclerotic lesions remains an uncommon event.…”

Periodontology/Oral Medicine: Periodontal infections and cardiovascular disease—how strong is the association?

“…Since the initial discovery of C. pneumoniae using electron microscopy in atheromatous plaques from autopsy specimens (Shor et al, 1992) numerous studies have confirmed and extended the original observation. Examination of atherectomy specimens for C. pneumoniae antigens using immunological methods (Campbell et al, 1995;Grayston et al, 1995;Muhlestein et al, 1996;Chiu et al, 1997) or C. pneumoniae DNA using polymerase chain reaction (PCR) techniques (Blasi et al, 1996;Maass et al, 1998) has revealed the presence of chlamydial components approximately 30-75% of the time. In addition, viable organisms have been isolated from human atherectomy specimens (Ramirez et al, 1996;Jackson et al, 1997;Maass et al, 1998).…”