Chlamydia pneumoniae Does Not Influence Atherosclerotic Plaque Behavior in Patients With Established Carotid Artery Stenosis

Abstract

Background and Purpose-Research for infectious agents in the etiology of atherosclerosis has identified Chlamydia pneumoniae as a possible candidate. While there is evidence of an association between presence of this microorganism and atherosclerosis, it is unclear whether infection has a genuinely etiologic role in this disease, whether its presence influences clinical outcomes, and, if so, at which stages of disease this occurs. We have approached this issue in patients with advanced carotid artery atherosclerosis using molecular biological detection methods and clinically relevant indicators of pathology in carotid artery atheroma to determine whether the presence of C pneumoniae correlates with plaque instability. Methods-C pneumoniae was detected with the use of a sensitive nested polymerase chain reaction. Preoperative embolization and preoperative infarcts were recorded with the use of transcranial Doppler insonation of the middle cerebral artery and cerebral CT, respectively. Results-C pneumoniae DNA was detected in 25.5% of a cohort of 98 symptomatic patients. There was no significant difference in plaque stability as measured by embolization rates between the chlamydial-positive and -negative specimens. There was also no correlation between the number of ipsilateral hemispheric infarcts in the territory of the middle cerebral artery and chlamydial status. Conclusions-This study confirms that C pneumoniae is a common finding in atherosclerotic plaques of the carotid artery but suggests that the presence of the infectious organism has little detectable impact on plaque instability when measured by clinically significant markers. This raises important questions for the rationale of antibiotic therapy in atherosclerosis.

Is the Perceived Association between Chlamydia pneumoniae and Vascular Diseases Biased by Methodology?

“…Analyzing 33 studies with regard to hybridization in the detection of C. pneumoniae DNA, we found 11 studies in which only gel electrophoresis had been used to visualize PCR products (8,16,18,30,37,38,40,(42)(43)(44)(45). In the other 22 studies, PCR results were confirmed by hybridization (2, 5, 6, 12, 14, 19, 23-26, 28, 29, 31-35, 39, 47, 48, 50 …”

Inflammation and Infections as Risk Factors for Ischemic Stroke

“…64 Clinical data support that the presence of C pneumoniae in carotid stenoses increases local thrombogenicity and the risk of infarction, 62,81 but not all results favor this hypothesis. 65 Some [82][83][84][85] but not all 86,87 seroepidemiological studies reported an association between past C pneumoniae infection and asymptomatic carotid atherosclerosis or increased intimamedia thickness. A prospective study found an independent association between C pneumoniae seropositivity and (1) progression of the intima-media thickness and (2) ischemic events, effects that were particularly expressed in patients with increased CRP.…”

Chlamydia pneumoniae and Atherosclerosis: Critical Assessment of Diagnostic Methods and Relevance to Treatment Studies

“…Shor et al (129) reported a strong association between atheromatous lesions and C. pneumoniae; however, minimal lesions were C. pneumoniae positive as often as severe lesions were. (147) 1999 IH N ϩ H MOMP coding ND Bartels et al (6) 1999 IH N ϩ H Cloned PstI N D Nadrchal et al (97) 1999 IH N 16S rRNA ND Thomas et al (138) 1999 IH N ϩ H MOMP coding ND Blasi et al (32) 1999 TriPure N Cloned PstI RT-PCR 16S rRNA Jantos et al (64) 1999 IH ϩ Qiagen S ϩ H 16S rRNA N MOMP coding Bartels et al (7) 2000 IH N ϩ H Cloned PstI N D Berger et al (8) 2000 IH Q-PCR 16S rRNA ND Gibbs et al (38) 2000 …”