Effect of methylprednisolone on predicted myocardial infarction size in man

Anti-inflammatory therapies in myocardial infarction: failures, hopes and challenges

In the infarcted heart, the damage-associated molecular pattern proteins released by necrotic cells trigger both myocardial and systemic inflammatory responses. Induction of chemokines and cytokines and up-regulation of endothelial adhesion molecules mediate leukocyte recruitment in the infarcted myocardium. Inflammatory cells clear the infarct of dead cells and matrix debris and activate repair by myofibroblasts and vascular cells, but may also contribute to adverse fibrotic remodelling of viable segments, accentuate cardiomyocyte apoptosis and exert arrhythmogenic actions. Excessive, prolonged and dysregulated inflammation has been implicated in the pathogenesis of complications and may be involved in the development of heart failure following infarction. Studies in animal models of myocardial infarction (MI) have suggested the effectiveness of pharmacological interventions targeting the inflammatory response. This article provides a brief overview of the cell biology of the post-infarction inflammatory response and discusses the use of pharmacological interventions targeting inflammation following infarction. Therapy with broad anti-inflammatory and immunomodulatory agents may also inhibit important repair pathways, thus exerting detrimental actions in patients with MI. Extensive experimental evidence suggests that targeting specific inflammatory signals, such as the complement cascade, chemokines, cytokines, proteases, selectins and leukocyte integrins, may hold promise. However, clinical translation has proved challenging. Targeting IL-1 may benefit patients with exaggerated post-MI inflammatory responses following infarction, not only by attenuating adverse remodelling but also by stabilizing the atherosclerotic plaque and by inhibiting arrhythmia generation. Identification of the therapeutic window for specific interventions and pathophysiological stratification of MI patients using inflammatory biomarkers and imaging strategies are critical for optimal therapeutic design.

Corticosteroids and cardiopulmonary bypass : a review of clinical investigations

Traditionally, corticosteroids have been administered to patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) to ward off detrimental physiologic alterations associated with activation of the systemic inflammatory response, yet few well-controlled investigations exist, and use of these drugs in this setting remains controversial. This review article critically examines the results of clinical investigations in this area, and certain conclusions are suggested. The constellation of findings indicate that corticosteroids offer no clinical benefits to patients undergoing cardiac surgery with CPB and in fact may be detrimental. Further directions for clinical research in this area are also suggested.

Mechanism of the beneficial effect of dexamethasone on myocardial cell integrity in acure myocardial ischemia

Dexamethasone (6 mg/kg) given intravenously to anesthetized cats exerted no significant hemodynamic effect on control open-chest cats or in cats subjected to acute myocardial ischemia by coronary artery ligature. However, dexamethasone normalized elevated S-T segments toward preischemic values, and prevented much of the increase in plasma CPK activity following coronary artery ligation. Moreover, dexamethasone prevented loss of CK activity within ischemic myocardial tissue five hours after the onset of ischemia. Dexamethasone also reduced the extent of ischemic damage as assessed by a nitro-blue tetrazolium staining technique, providing anatomic verification of the reduced ischemic damage. Moreover, dexamethasone prvented the swelling and vacuolization of myocardial lysosomes in the ischemic region, indicating a stabilization of lysosomal membranes within the heart. These data indicate that lysosomal disruption is an important consequence of myocardial ischemia and that early treatment with dexamethasone prevents the loss of myocardial lysosomal and cellular enzymes as reflected in normalization of the ECG and plasma CK activity of ischemic cats. In this way, dexamethasone may act to retard the spread of the developing infarct within the ischemic myocardium.