Protective effects of simvastatin on coronary artery function in swine with acute infection

Atherosclerosis Induced by Chlamydophila pneumoniae: A Controversial Theory

More than a century ago, inflammation and infection were considered to have atherogenic effects. The old idea that coronary heart disease (CHD) possibly has an infectious etiology has only reemerged in recent years. Atherosclerosis is the main pathological process involved in CHD and is, logically, the first place to look for infectious etiology. The process of atherosclerosis itself provides the first hints of potential infectious cause. Smooth muscle proliferation, with subsequent intimal thickening, luminal narrowing, and endothelial degeneration, constitutes the natural history of atherosclerosis, being with the severity and speed of these changes. Both viral and bacterial pathogens have been proposed to be associated with the inflammatory changes found in atherosclerosis. Recently, Chlamydophila pneumoniae (C. pneumoniae) has been implicated as a possible etiologic agent of coronary artery disease and atherosclerosis. New evidence which supports a role for C. pneumoniae in the pathogenesis of atherosclerosis has emerged. C. pneumoniae has been detected in atherosclerotic arteries by several techniques, and the organism has been isolated from both coronary and carotid atheromas. Recent animal models have suggested that C. pneumoniae is capable of inducing atherosclerosis in both rabbit and mouse models of atherosclerosis. Furthermore, human clinical treatment studies which examined the use of antichlamydial macrolide antibiotics in patients with coronary atherosclerosis have been carried out. The causal relationship has not yet been proven, but ongoing large intervention trials and research on pathogenetic mechanisms may lead to the use of antimicrobial agents in the treatment of CHD in the future.

Coronary flow and reactivity, but not arrhythmia vulnerability, are affected by cardioplegia during cardiopulmonary bypass in piglets

Background

Surgery under cardiopulmonary bypass (CPB) is still associated with significant cardiovascular morbidity in both pediatric and adult patients but the mechanisms are not fully understood. Abnormalities in coronary flow and function have been suggested to play an important role. Prior studies suggest protective effects on coronary and myocardial function by short intravenous (i.v.) infusion of cyclosporine A before CPB.

Methods

Barrier-bred piglets (10–12 kg, n=20) underwent CPB for 45 min, with or without antegrade administration of cardioplegic solution. Prior to CPB, half of the animals in each group received an i.v. infusion of 100 mg/kg cyclosporine A. The left anterior descending coronary flow velocity responses to adenosine, serotonin, and atrial pacing, as well as left ventricular function and postsurgical vulnerability to atrial fibrillation (Afib) were assessed by intracoronary Doppler, epicardial echocardiography, and in vivo electrophysiological study, before and 8 hours after surgery. Plasma C-reactive protein (CRP) and fibrinogen were measured at both time-points.

Results

Cyclosporine infusion did not influence any of the studied variables (p>0.4). Coronary peak flow velocity (cPFV) rose significantly after surgery especially in the cardioplegia group (p<0.01 vs. non-cardioplegia group and pre-surgery). cPFV responses to adenosine, but not to serotonin, tended to decrease (p=0.06) after surgery only in cardioplegia group (p=0.06; p=0.8 in non-cardioplegia group vs pre-surgery). Also, cPFV response to atrial pacing was lower in the cardioplegia than in the non-cardioplegia group (p=0.02). Neither vulnerability nor duration of induced Afib after CPB differed between groups (Chi-square p=0.4). Cyclosporine had no significant effect on coronary indexes or arrhythmia vulnerability (p>0.4). There was no difference in systolic myocardial function between groups at any time point.

Conclusion

In piglets, CPB with cardioplegia was associated with profound abnormalities in coronary vasomotor tone and receptor-related flow regulation, whereas arrhythmia vulnerability appeared to be comparable with that in non-cardioplegia group. In this study, preconditioning with cyclosporine had no detectable protective effect on coronary circulation or arrhythmia vulnerability after CPB.

Chlamydophila pneumoniae infection induces alterations in vascular contractile responses

Chlamydophila pneumoniae infection has been associated in previous studies with coronary artery disease. The live bacterium has been detected within atherosclerotic plaques and can induce the structural remodeling of the vessel wall. However, the direct effects of infection on the contractile characteristics of the arteries remain unknown. Left anterior descending coronary arteries isolated from porcine hearts were dissected and placed in culture medium for 72 hours before infection with C. pneumoniae. Contractile responses to high molar KCl and u46619 levels and relaxation responses to bradykinin and sodium nitroprusside were assessed at days 5 and 10 postinfection. C. pneumoniae induced decreases in both KCl- and u46619-induced contractile responses at both time points. The altered contractile responses coincided with a down-regulation of L-type Ca(2+) channels at both time points and inositol 1,4,5-triphosphate receptor (IP3R) levels at day 10 postinfection. Infection also induced attenuation of the endothelial-dependent relaxation response to bradykinin at day 10 postinfection. A decrease in endothelial nitric oxide synthase expression levels was noted at day 10 postinfection. Furthermore, an increase in superoxide production combined with an increase in p22phox expression levels was also observed at this time point. These findings indicate that C. pneumoniae infection can directly alter the vascular contractile responses in porcine coronary arteries, providing additional evidence for the role of C. pneumoniae infection in cardiovascular disease.

Prehospital statin and aspirin use and the prevalence of severe sepsis and acute lung injury/acute respiratory distress syndrome

OBJECTIVES

To determine whether prehospital statin use is associated with a lower risk of sepsis, acute lung injury/acute respiratory distress syndrome, and mortality in critically ill patients. We also investigated the effect of combined prehospital use of both statins and aspirin.

DESIGN

Cross-sectional analysis of a prospective cohort.

PATIENTS

A total of 575 critically ill patients admitted to the medical or surgical intensive care unit of an academic tertiary-care hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 575 patients, 149 (26%) were on statin therapy before hospitalization. A multivariable analysis including age, gender, current tobacco use, prehospital aspirin use, race, and Acute Physiology and Chronic Health Evaluation II score revealed that patients on statin therapy before hospitalization were less likely to have or develop severe sepsis (odds ratio 0.62, 95% confidence interval 0.40-0.96) or acute lung injury/acute respiratory distress syndrome (odds ratio 0.60, 95% confidence interval 0.36-0.99) during the first four intensive care unit days. In-hospital mortalities for patients with and without prehospital statin use (odds ratio 1.06, 95% confidence interval 0.62-1.83) were similar. Patients who had prehospital use of both statins and aspirin had the lowest rates of severe sepsis, acute lung injury/acute respiratory distress syndrome, and mortality.

CONCLUSIONS

Prehospital use of statins may be protective against sepsis and acute lung injury. This effect may be potentiated by prehospital aspirin use.

Infection-induced coronary dysfunction and systemic inflammation in piglets are dampened in hypercholesterolemic milieu

The synergism of infection with conventional cardiovascular risk factors in atherosclerosis is much debated. We hypothesized that coronary arterial injury correlates with infection recurrence and pathogen burden and is further aggravated by hypercholesterolemia. Forty-two Göttingen minipigs were assigned to repeated intratracheal inoculation of PBS, Chlamydia pneumoniae (Cpn), or both Cpn and influenza virus at 8, 11, and 14 wk of age. Animals were fed either standard or 2% cholesterol diet (chol-diet). At 19 wk of age coronary vasomotor responses to acetylcholine (ACh) and adenosine were assessed in vivo and blood and tissue samples were collected. Nonparametric tests were used to compare the groups. In cholesterol-fed animals, total cholesterol/HDL was significantly increased in infected animals compared with noninfected animals [3.13 (2.17–3.38) vs. 2.03 (1.53–2.41), respectively; P = 0.01]. C-reactive protein (CRP) rose in infected animals [10.60 (4.96–18.00) vs. 2.47 (1.44–3.01) μg/ml in noninfected; P < 0.01] without significant difference between the mono- and coinfected groups. Among coinfected animals, both CRP and haptoglobin were lower in those fed chol-diet than in those fed standard diet ( P < 0.05). The vasoconstricting response to ACh was most prominent in coinfected animals {769.3 (594–1,129) cm; P = 0.03 vs. noninfected [342 (309–455) cm] and P = 0.07 vs. monoinfected [415 (252.5–971.8) cm]}. Among monoinfected animals, similar to CRP, a trend for less vasoconstriction was observed in those fed chol-diet ( P = 0.08). Coinfection of piglets appears to be associated with more pronounced coronary muscarinic vasomotor dysfunction. In monoinfected animals, use of chol-diet seems to dampen both coronary dysfunction and systemic inflammation induced by infection.

Chlamydophila pneumoniae infection in patients undergoing carotid artery stent

Although several reports have correlated Chlamydophila pneumoniae (CP) infection with carotid endarterectomy and coronary stent, no data have been reported on the potential relationship between this pathogen and carotid artery stenting (CAS). Hence, we evaluated 47 subjects, 27 symptomatic and 20 asymptomatic, before CAS intervention and during the follow up, for the presence of CP DNA and anti-CP antibodies, including chlamydial HSP60 (Cp-HSP60). Before stent placement, CP DNA was detected exclusively in symptomatic patients, all of whom were also positive for CP IgG and IgA and 85.7 percent of them also had CP-HSP60 antibodies. At the follow-up, all CP DNA positive and 11 out of the 13 symptomatic patients with Cp-HSP60 antibodies became negatives. In contrast, no change was observed for CP- IgA antibodies. Despite the small number of patients, the present study advocates an important role of CP infection in symptomatic patients with carotid artery disease. Our findings also suggest that stent placement and/or therapy might have a role in favouring resolution of inflammation, though not affecting persistence of CP infection.

Possibilities for therapeutic interventions in disrupting Chlamydophila pneumoniae involvement in atherosclerosis

Strong sero-epidemiologic, pathologic, and experimental evidence suggests that Chlamydophila pneumoniae (Cpn) infection may play a causative role in the development of atherosclerosis. Cpn is an obligate intracellular gram-negative bacterium that is responsible for 10% of cases of community-acquired pneumonia. In addition to its presence in the respiratory tract, live Cpn has been found within atherosclerotic plaques. Experimental findings have established Cpn's ability to infect vascular cells and elicit important atherogenic responses. Furthermore, Cpn infection can promote atherosclerotic development in different animal models. To date however, large-scale antibiotic clinical trials have not been effective in preventing major cardiovascular events. It is becoming apparent that Cpn undergoes a persistent state of infection, which is refractory to current chlamydial antibiotics. New treatment strategies that are effective toward acute and persistent forms of Cpn infection are needed in order to effectively eradicate the bacterium within the vascular wall. Possible therapeutics targets include Cpn-specific proteins and machinery directly involved in their survival, replication and maintenance. Alternatively, selectively targeting host cell pathways and machinery required for Cpn's actions in vascular cells also represent potential treatment strategies for atherosclerosis.

[Effect of the simvastatin in abdominal sepsis of diabetic rats]

OBJECTIVE

Infection and sepsis are major causes of morbidity and mortality after surgery of diabetic patients. Statins have been shown to exhibit anti-inflammatory and immunomodulatory (pleiotropic) effects, independent of lipid lowering. This study aimed to observe whether the pretreatment with simvastatin in a cecal ligation and perforation model of sepsis is beneficial in diabetic rats.

METHODS

Fifty six Wistar rats were randomly assigned to non-diabetic group (n=28), and streptozotocin-induced diabetic group (n=28). Abdominal sepsis was induced in 14 diabetic and in 14 non diabetic rats and the other 28 rats were allocated on sham group. Sepsis rats and sham rats (each with 7 animals) were treated with oral simvastatin (20 mg kg-1 day-1) or normal saline solution 0.9%. Peripheral blood TNFalpha, IL-1beta, IL-6, C-reactive protein, procalcitonin, leukocytes and neutrophils were tested in all the animals. Statistical analysis was done by ANOVA and Tukey test, with p<0.05.

RESULTS

Simvastatin reduced mortality in diabetic rats. Peripheral blood TNFalpha, IL-1beta, IL-6, C-reactive protein, procalcitonin, leukocytes and neutrophils were lower in diabetic and non diabetics septic rats treated with simvastatin, than after saline treatment.

CONCLUSION

Simvastatin showed anti-inflammatory effect, which could play some protection against the progress of sepsis in diabetic rats.

New perspectives of infections in cardiovascular disease

Infections have been recognized as significant causes of cardiac diseases for many decades. Various microorganisms have been implicated in the etiology of these diseases involving all classes of microbial agents. All components of the heart structure can be affected by infectious agents, i.e. pericardium, myocardium, endocardium, valves, autonomic nervous system, and some evidence of coronary arteries. A new breed of infections have evolved over the past three decades involving cardiac implants and this group of cardiac infectious complications will likely continue to increase in the future, as more mechanical devices are implanted in the growing ageing population. This article will review the progress made in the past decade on understanding the pathobiology of these infectious complications of the heart, through advances in genomics and proteomics, as well as potential novel approach for therapy.An up-to-date, state-of-the-art review and controversies will be outlined for the following conditions: (i) perimyocarditis; (ii) infective endocarditis; (iii) cardiac device infections; (iv) coronary artery disease and potential role of infections.