ABSTRACT
BACKGROUND: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases' (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). METHODS: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. RESULTS: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. CONCLUSIONS: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.
Subject(s)
Inflammation/drug therapy , Metalloproteases/genetics , Myocarditis/drug therapy , Simvastatin/pharmacology , Animals , Autoimmune Diseases/drug therapy , Autoimmune Diseases/genetics , Autoimmune Diseases/immunology , Cardiotonic Agents/pharmacology , Echocardiography , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Inflammation/genetics , Inflammation/immunology , Inflammation/pathology , Metalloproteases/antagonists & inhibitors , Models, Animal , Myocarditis/genetics , Myocarditis/immunology , Myocarditis/pathology , Rats , Ventricular Dysfunction, Left/drug therapy , Ventricular Dysfunction, Left/pathology , Ventricular Dysfunction, Left/prevention & controlABSTRACT
Contact tracing and quarantine are well established non-pharmaceutical epidemic control tools. The paper aims to clarify the impact of these measures in evolution of epidemic. The proposed deterministic model defines a simple rule on the reproduction number [Formula: see text] in terms of ratio of diagnosed cases and, quarantine and transmission parameters. The model is applied to the early stage of Covid19 crisis in Poland. We investigate 3 scenarios corresponding to different ratios of diagnosed cases. Our results show that, depending on the scenario, contact tracing prevented from 50% to over 90% of cases. The effects of quarantine are limited by fraction of undiagnosed cases. The key conclusion is that under realistic assumptions the epidemic can not be controlled without any social distancing measures.