Significance of pericardial cytokines in giant cell myocarditis in rats--pathological comparison to viral myocarditis in mice

Technologies for intrapericardial delivery of therapeutics and cells

The pericardium, which surrounds the heart, provides a unique enclosed volume and a site for the delivery of agents to the heart and coronary arteries. While strategies for targeting the delivery of therapeutics to the heart are lacking, various technologies and nanodelivery approaches are emerging as promising methods for site specific delivery to increase therapeutic myocardial retention, efficacy, and bioactivity, while decreasing undesired systemic effects. Here, we provide a literature review of various approaches for intrapericardial delivery of agents. Emphasis is given to sustained delivery approaches (pumps and catheters) and localized release (patches, drug eluting stents, and support devices and meshes). Further, minimally invasive access techniques, pericardial access devices, pericardial washout and fluid analysis, as well as therapeutic and cell delivery vehicles are presented. Finally, several promising new therapeutic targets to treat heart diseases are highlighted.

Frequency of pleural effusion in acute bronchiolitis and its effect on prognosis

AIM

To analyze the frequency of pleural effusion and the effect on prognosis in children with acute bronchiolitis.

METHODS

A total of 69 infants aged 1-24 months with acute bronchiolitis were studied between September 2009 and December 2010. All patients'age, sex, breastfeeding duration, exposure to smoking, history of using vitamin D, symptoms duration, physical examination and laboratory findings were recorded. Bronchiolitis score and predisposing factors that influence the disease process were determined. Thorax ultrasonography was carried out in all patients, who were evaluated on the 3rd and 7th day of the treatment.

RESULTS

Mean age of patients (43 boys, 26 girls) was 11.97 ± 0.69 months (median 11 months). Breastfeeding duration was 8.26 ± 0.56 months (median 8 months). According to bronchiolitis score, 52 patients (75.4%) had mild and moderate bronchiolitis and 17 (24.6%) had severe bronchiolitis; 34 patients (49.2%) had pleural effusion. There was no relation between pleural effusion and symptoms. Frequency of pleural effusion was significantly higher in patients with risk factors.

CONCLUSIONS

This study demonstrated that most of the acute bronchiolitis cases in the infants studied were accompanied by pleural effusion. Pleural effusion in acute bronchiolitis had no effects on prognosis.

Amiodarone minimizes experimental autoimmune myocarditis in rats

Amiodarone, a promising drug for the treatment of tachyarrythmias, was recently found to have immunomodulatory effects in vitro. We hypothesized that amiodarone would affect the immune system in vivo and examined the effect of amiodarone on myocarditis in rats. We induced experimental autoimmune myocarditis in rats by cardiac myosin immunization and treated the animals with an intraperitoneal injection of amiodarone at 25 mg/kg/every other day, 10 times after the induction of experimental autoimmune myocarditis. In the treated group, both microscopic and macroscopic examinations showed reduced heart weights, a mild and localized infiltration of inflammatory cells and fibrosis in the myocardium, and a mild congestion in the liver and lungs as compared with the control group. The phenotypic distribution of lymphocytes in peripheral blood showed a significant decrease in the CD4/CD8a ratio in the treated group, but not in the control group. The proportion of mast cells involved in inflammatory cell infiltration was lower in the treated group than the control group. In vitro, amiodarone inhibited the proliferation of mast cells by arresting them in the G2 phase of the cell cycle. These results indicated that amiodarone minimized the progression of experimental autoimmune myocarditis, suggesting a potential therapeutic role for amiodarone treatment in patients suffering from myocarditis, especially myocarditis complicated by cardiac arrhythmias. One possible mechanism by which amiodarone minimizes the progression of experimental autoimmune myocarditis may be to affect the immune system via the immunomodulatory effects on T cell and mast cell functions.

Methimazole interferes with the progression of experimental autoimmune myocarditis in rats

In order to ascertain whether methimazole, a drug commonly used for the treatment of hyperthyroidism, interferes with the progression of autoimmune-mediated myocardial injury, we investigated the effect of methimazole on experimental autoimmune myocarditis (EAM) in rats. EAM was induced by immunization with porcine cardiac myosin. Methimazole administration markedly slowed the body weight growth in both normal and EAM rats, but did not induce morphologic change of cardiac tissue in normal rats. In EAM rats, macroscopic examination revealed discoloration of the cardiac surface, and histopathological examination by light microscopy showed extensive myocardial necrosis, infiltration by inflammatory cells and myocardial fibrosis. In the EAM rats treated with methimazole, the discolored areas on the cardiac surface were markedly diminished in size, and the myocardial necrosis, cellular infiltration and fibrosis were significantly less severe. To identify the mechanism responsible of this effect, we investigated the change of regulatory lymphocyte subsets in peripheral blood using an immunofluorescence technique with a flow cytometer. A decrease in the helper/suppressor T cell ratio as a result of the increased proportion of suppressor T cells and a decrease in the proportion of B cells were observed in normal rats after methimazole administration, and similar findings were made in the EAM rats treated with methimazole. These results indicate that methimazole interferes with the progression of EAM, and immunosuppression may, at least in part, be involved in the inhibitory effect of methimazole on EAM in rats.