Cocaine enhances myocarditis induced by encephalomyocarditis virus in murine model

A Case of Clozapine-Induced Myocarditis in a Young Patient with Bipolar Disorder

We present a case of drug-induced myocarditis manifesting as acute heart failure in a young patient with bipolar disorder being treated for depression. The case describes a 20-year-old man being treated in the psychiatry ward for worsening depression when he started complaining of chest pain and shortness of breath. His list of medications included clozapine, lithium, lorazepam, and haloperidol. The main findings on physical examination were tachycardia, low-grade fever, crackles in both lung bases on auscultation, and the absence of any notable edema. Abnormal labs included a troponin of 0.9, with a CK of 245 and CK-MB of 3.1. An ECG revealed sinus tachycardia and left anterior fascicular block (LAFB). An echocardiogram revealed global hypokinesis, severe left ventricular dysfunction with an ejection fraction estimated at 20%. The patient had an admitting diagnosis of acute left ventricular systolic dysfunction likely secondary to drug-induced myocarditis (suspect clozapine) versus acute coronary syndrome. He was managed conservatively and transferred to another facility for endomyocardial biopsy confirming myocarditis. This case is an example of one of the most typical presentations of suspected drug-induced acute myocarditis and will hopefully prompt the reader to think of this underdiagnosed entity in the right clinical setting.

Propranolol ameliorates and epinephrine exacerbates progression of acute and chronic viral myocarditis

Recent studies point to important interactions between proinflammatory cytokines and neurohumoral mediators in heart failure. Here we investigate the influence of the β-adrenergic system on cytokines and neurohumoral factors and the sequelae of viral myocarditis. In an experimental model with virus-infected BALB/c mice, we studied the acute and chronic effects of epinephrine and propranolol on myocardial morphology, cytokine gene expression, and survival. BALB/c mice were inoculated with the encephalomyocarditis virus (EMCV) or sham inoculated with saline and followed for 30 days. Epinephrine increased the severity of inflammatory cell infiltration and myocardial necrosis induced by EMCV. Gene expression of TNF-α, IL-6, and IL-10 was markedly enhanced by epinephrine in EMCV-inoculated mice. Survival rate after 30 days was reduced to 40% in epinephrine-treated EMCV-inoculated mice compared with 70% in untreated EMCV-inoculated mice ( P < 0.05). Treatment with the β-blocker propranolol significantly decreased mortality, myocardial necrosis, and infiltration of inflammatory cells in EMCV-inoculated mice. Propranolol also suppressed gene expression of TNF-α, IL-6, and IL-10. A single dose of epinephrine 120 days after EMCV inoculation caused sudden death in 70% of infected mice; propranolol significantly reduced incidence of death to 33%. These results indicate that acute and chronic stages of viral myocarditis are modulated by the β-adrenergic system and its interactions with proinflammatory cytokines.

Cocaine and catecholamines enhance inflammatory cell retention in the coronary circulation of mice by upregulation of adhesion molecules

Cocaine treatment of mice with viral myocarditis significantly increases neutrophil infiltration into the myocardium and exacerbates the inflammatory response. The mechanisms of these effects are unknown; however, it may be that cocaine increases circulating catecholamines and consequently increases inflammatory cell adhesion to the coronary endothelium. Here, we examined the hypothesis that cocaine enhances inflammatory cell infiltration via catecholamine-induced upregulation of cell adhesion molecule (CAM) expression in adult BALB/c mouse hearts. Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial leukocyte adhesion molecule-1 (E-selectin), and leukocyte adhesion molecule-1 (L-selectin) were detected by gene array analysis, RT-PCR, Western blotting, and immunohistochemical staining. CAMs were significantly upregulated in cocaine-treated mouse hearts. beta-Adrenergic stimulation with epinephrine also upregulated CAM expression, confirming the effects obtained with cocaine. Beta-adrenergic blockade with propranolol inhibited epinephrine-induced CAM expression. In hearts infused with polymorphonuclear neutrophils (PMN), an increased adhesion of PMN to the coronary endothelium was observed in cocaine-treated and epinephrine-treated mouse hearts compared with control hearts. Blocking antibodies against ICAM-1, E-selectin, and L-selectin significantly inhibited epinephrine-enhanced PMN adhesion, whereas anti-VCAM-1 had lesser effects. Our findings suggest that cocaine-induced neutrophil infiltration is mediated by beta-adrenergic stimulation through upregulation of CAM expression, which enhances PMN adhesion. Conversely, beta-adrenergic blockade with propranolol inhibits the effects of cocaine and epinephrine on CAM expression and decreases PMN adhesion to the coronary endothelium. These observations may be of significance for the development of preventative and therapeutic approaches to patients with cocaine- or catecholamine-induced myocarditis.

Antiviral therapy with non-selective β-blockers: preliminary experimental and clinical corroboration

Treatment with non-selective beta-blockers has been proposed to have an indirect antiviral activity acting via an enhanced performance of the immune system, and the mechanism of this activity has been laid out earlier. Experimental and clinical findings are presented that corroborate the hypothesis that inhibiting the immunosuppressive and stress-related cAMP-PKA pathway will enhance the immune system's ability to recognize foreign antigen and to access its vast repertory in an improved way, resulting in an indirect antiviral activity. Other drugs having an inhibitory effect on the cAMP-PKA pathway in cells of the immune system and therefore expected to have a comparable activity spectrum with different specific side-effects are presented, for example aspirin. Additionally the so far unexplained anticancer activity of aspirin is related to the same mechanism of an enhanced performance of the immune system.