Presence of Chlamydia pneumoniae in patients with and without atherosclerosis

Is there any relationship between Chlamydophila pneumoniae and coronary atherosclerosis among Iranians?

Background:

Atherosclerosis is a coronary heart disease, andis the most common cause of death in the industrialized world. Some studies suggested that atherosclerosis may be triggered by infectious agents, mostly Chlamydophila pneumoniae. However, the role of C. pneumoniae in the pathogenesis of coronary atherosclerosis is still controversial.

Objectives:

This study was performed to evaluate whether there is a significant association between coronary artery atherosclerosis and C. pneumoniae by the polymerase chain reaction (PCR) method.

Materials and Methods:

This case-control study was carried out on formalin-fixed paraffin-embedded tissue biopsies of the coronary arteries obtained from 30 patients with coronary atherosclerosis and 30 subjects without atherosclerosis living in Northeast of Iran. All subjects' weight and height were determined, and the body mass index was calculated. We also reviewed the medical history and previous laboratory reports of patients. Deoxyribonucleic acid (DNA) was extracted, and C. pneumonia DNA was amplified and detected using PCR assay.

Results:

The age of the patients in the study group was from 18 to 50 years, and the male to female ratio was 5:1. Only oneout of the 30 coronary tissue samples had positive PCR for C. pneumoniae (3.3%), while it was negative for patients in the control group.

Conclusions:

This study showed that C. pneumoniae infection is not strongly associated with coronary artery atherosclerosis in Northeast of Iran.

Chlamydophila pneumoniae infection and cardiovascular disease

Atherosclerosis is a multifactorial vascular inflammatory process; however, the inciting cause for inflammation remains unclear. Two decades ago, Chlamydophila pneumoniae (formerly Chlamydia pneumoniae) infection was proposed as a putative etiologic agent. We performed a PubMed search using the keywords Chlamydia and atherosclerosis in a Boolean query to identify published studies on C. pneumoniae and its role in atherogenesis, and to understand research interest in this topic. We found 1,652 published articles on this topic between 1991 and 2011. We analyzed relevant published studies and found various serological, molecular, and animal modeling studies in the early period. Encouraged by positive results from these studies, more than a dozen antibiotic clinical-trials were subsequently conducted, which did not find clinical benefits of anti-Chlamydophila drug therapy. While many researchers believe that the organism is still important, negative clinical trials had a similar impact on overall research interest. With many novel mechanisms identified for atherogenesis, there is a need for newer paradigms in Chlamydophila-atherosclerosis research.

Chlamydia pneumoniae infection in patients after kidney transplantation treated with spiramycin

INTRODUCTION

Previous research has pointed to a role of Chlamydia pneumoniae infection in the development of chronic renal allograft dysfunction, chronic liver rejection, and vasculopathy in the transplanted heart. The aim of this study was to evaluate the presence of C. pneumoniae prior to and after kidney transplantation as well as to determine the role of spiramycin therapy among kidney transplant recipients.

MATERIALS AND METHODS

The study group consisted of 50 patients (25 pairs) who received kidney transplants from cadaveric donors. One of the 2 kidneys from a donor was transplanted to a patient randomized to spiramycin (2 x 3 million U/d orally for 3 months; group S) and the other to a patient assigned as control (group C). Markers of infection were assessed on day 1 posttransplantation and 3 months later (average, 94 days). All 50 patients were examined for the presence of bacterial DNA in peripheral blood leukocytes using real-time polymerase chain reaction (PCR) and for titers of serum anti C. pneumoniae immunoglobulin (IgG) and IgA antibodies using microimmunofluorescence (MIF). C. pneumoniae infection was diagnosed by the presence of C. pneumoniae DNA in peripheral blood leukocytes or positive antibodies of both classes.

RESULTS

C. pneumoniae infection was initially diagnosed in 14 patients among group S and 8 patients among group C (P = not significant [ns]) and after 3 months in 12 and 9 patients, respectively (P = ns). Conversion from positive to negative C. pneumoniae status occured in 7 patients among group S and 1 patient among group C (P = .04). Conversion from negative to positive C. pneumoniae status occured in 5 patients from group S and 2 patients from group C (P = ns).

CONCLUSIONS

These results suggest a possible role for spiramycin treatment of C pneumoniae infection in kidney allograft recipients. C. pneumoniae infection diagnosis and treatment should be considered to be routine for every patient awaiting transplantation.

Role of Chlamydia pneumoniae in atherosclerosis

Cardiovascular disease, resulting from atherosclerosis, is a leading cause of global morbidity and mortality. Genetic predisposition and classical environmental risk factors explain much of the attributable risk for cardiovascular events in populations, but other risk factors for the development and progression of atherosclerosis, which can be identified and modified, may be important therapeutic targets. Infectious agents, such as Chlamydia pneumoniae, have been proposed as contributory factors in the pathogenesis of atherosclerosis. In the present review, we consider the experimental evidence that has accumulated over the last 20 years evaluating the role of C. pneumoniae in atherosclerosis and suggest areas for future research in this field.