Antibiotic therapy in coronary heart disease--where do we currently stand?

Cytomegalovirus infection and atherosclerosis in candidate of coronary artery bypass graft

Background:

Although there is enough evidence that infectious agents such as Chlamydia pneumonia and Helicobacter pylori may play a pathogenic role in atherosclerosis, this role for cytomegalovirus (CMV) is yet controversial.

Objectives:

The aim of the present study was to detect CMV-DNA in atherosclerotic plaques in patients who underwent coronary artery bypass graft (CABG).

Patients and Methods:

In this case-control study, candidates for CABG (cases) and patients with valvular or congenital malformation but without atherosclerotic plaques (controls) were studied from 2012 to 2013 at Golestan hospital, Ahvaz, IR Iran. Demographic and laboratory data were collected. Atherosclerotic and histological samples were obtained from visible plaques and from aorta by the surgeon. All the samples were examined for the presence of CMV-DNA by polymerase chain reaction (PCR) method using a commercial kit (SinaClon, Tehran, IR Iran).

Results:

The mean ages in case and control groups were 60.8 ± 6.8 and 57.5 ± 11.5 years, respectively, with no significant difference (P = 0.09). Thirty patients (54.5%) in case and 32 (58.2%) in control groups were male with no significant difference (P = 0.7). CMV-DNA was present in 8 (14.5%) of the cases and 2 (4%) of the controls. CMV-DNA was associated with higher risk of atherosclerosis (OR: 7.7, 95% CI = 1.1-51.4, P = 0.03). Of the total normal aortic samples (55 in cases and 55 in controls), there was no individual with simultaneous positive CMV-DNA among aortic atherosclerotic and normal tissue samples.

Conclusions:

The presence of CMV-DNA in aortic plaques is associated with increased risk of atherosclerosis. CMV infection may be considered as an independent risk factor for this event.

High rate of seropositivity of Chlamydia pneumoniae IgA in male patients with nonalcoholic steatohepatitis

The aim of this study was to investigate if there was any relationship between nonalcoholic steatohepatitis and the rate of Chlamydia pneumoniae seropositivity in a male population. Fifteen men with nonalcoholic steatohepatitis and 20 healthy men were enrolled in the study. The seropositivity rate of Chlamydia pneumoniae immunoglobulin A in the nonalcoholic steatohepatitis and control groups was 53.3 and 5%, respectively. The rate of Chlamydia pneumoniae immunoglobulin A positivity was significantly higher in the nonalcoholic steatohepatitis group than the controls (P = 0.002), while such a difference did not occur for Chlamydia pneumoniae immunoglobulin G positivity (P > 0.05). There is an association between nonalcoholic steatohepatitis and persistent Chlamydia pneumoniae infection as a probable causative or triggering agent. These findings suggest that further studies are necessary to clarify this association.

Chlamydia pneumoniae resists antibiotics in lymphocytes

Chlamydia pneumoniae infection of lymphocytes in blood has been well documented, and it is apparent that control of this pathogen in these cells may be critical in the development of chronic inflammatory diseases associated with infection by this bacterium. The activity of antibiotics against C. pneumoniae in lymphocytes was assessed in this study by utilizing an in vitro infection model with lymphoid cells. The results obtained indicated that although all of the antibiotics tested showed remarkable activity against bacterial growth in epithelial cells, C. pneumoniae in lymphocytes was less susceptible to antibiotics than was bacterial growth in epithelial cells, which are widely used for the evaluation of anti-C. pneumoniae antibiotics.

Chlamydia pneumoniae and atherosclerosis -- what we know and what we don't

The clinical manifestations of atherosclerosis include coronary artery disease (CAD), stroke, abdominal aortic aneurysm and peripheral vascular disease. World-wide, CAD and stroke are the leading causes of death and disability. The recognition of atherosclerosis as an inflammatory disease in its genesis, progression and ultimate clinical manifestations has created an interesting area of vascular research. Apart from those well-known traditional risk factors for atherosclerosis, novel and potentially treatable atherosclerotic risk factors such as homocysteine (an amino acid derived from the metabolism of dietary methionine that induces vascular endothelial dysfunction) and infections have emerged. In fact, the century-old 'infectious' hypothesis of atherosclerosis has implicated a number of micro-organisms that may act as contributing inflammatory stimuli. Although cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae are the three micro-organisms most extensively studied, this review will focus on C. pneumoniae. Collaborative efforts from many disciplines have resulted in the accumulation of evidence from seroepidemiological, pathological, animal model, immunological and antibiotic intervention studies, linking C. pneumoniae with atherosclerosis. Seroepidemiological observations provide circumstantial evidence, which is weak in most prospective studies. Pathological studies have demonstrated the preferential existence of C. pneumoniae in atherosclerotic plaque tissues, while animal model experiments have shown the induction of atherosclerosis by C. pneumoniae. Finally, immunological processes whereby C. pneumoniae could participate in key atherogenic and atherothrombotic events have also been identified. Although benefits of the secondary prevention of atherosclerosis have been demonstrated in some antibiotic intervention studies, a number of negative studies have also emerged. The results of the ongoing large prospective human antibiotic intervention trials may help to finally establish if there is a causal link between C. pneumoniae infection and atherosclerosis.