Patterns of cellular injury in myocardial ischemia determined by monoclonal antimyosin.

Abstract

The development of cellular injury in the rat left ventricle resulting from left coronary artery occlusion was examined by immunofluorescence after intravenous injection of monoclonal antimyosin. Cardiac muscle cells that bound antimyosin during ischemia were localized by staining sections with fluorescein-conjugated anti-mouse IgG. Fluorescent staining was detectable within the ischemic region of the left ventricle 3 hr after occlusion and injection of antimyosin. After 6 hr of ischemia, the highly irregular margin of the ischemic zone was clearly outlined by fluorescent cells. At 3-6 hr after occlusion, marked heterogeneity in cellular staining was observed in the epicardial half of the ischemic area, with intensely fluorescent cells intermixed with cells of markedly lower fluorescence. By 24 hr, a homogeneous pattern of staining was observed throughout the ischemic zone. In nonischemic regions of the heart and in rats treated for 24 hr with antimyosin without occlusion, there were only background levels of staining. We conclude that: (i) visualization of ischemic cells via antimyosin provides a sensitive means for examining developing patterns of injury; (ii) the heterogeneity of staining during early ischemia may reflect variation in cellular resistance to deprivation; and (ini) the pattern of fluorescence at the margin of the occluded region indicates that the "border zone" is composed of interdigitating ischemic and nonischemic tissues.The temporal and spatial distribution of myocardial injury developing in response to coronary occlusion has been the subject of many investigations. In contrast to emerging techniques such as scintiscans, positron emission tomography, and NMR, which provide assessment of ischemic zones, methods have not been exploited by which damaged cells would be individually labeled and directly visualized microscopically. A suitable method would unequivocally identify injured cells and permit large areas to be surveyed quickly. Such a method requires the development of a probe that penetrates cell membranes and remains confined to the cells. Defects in the plasma membrane of ischemic myocytes were observed by Jennings et al., occasionally after 1 hr, commonly after 2 hr of coronary occlusion, and were considered a manifestation of irreversible injury (1, 2). In work by Shell and colleagues, creatine phosphokinase appeared in the circulation in proportion to its depletion in ischemic myocardium (3). The loss of this enzyme is a manifestation of the increased permeability of ischemic cell membranes. Haber and co-workers demonstrated the preferential uptake of isotopically labeled specific antibodies to myosin in ischemic heart muscle (4-6). Apparently, analogous to the egress of macromolecular enzymes, the antibodies penetrated defective cell membranes to bind to the essentially insoluble intracellular protein, myosin.In this report, we describe the use of fluorescein-labeled monoclonal anticardiac myosin to examine the patterns of developing ischemic injury at the cellular level...

Overexpression of insulin-like growth factor-1 in mice protects from myocyte death after infarction, attenuating ventricular dilation, wall stress, and cardiac hypertrophy.

“…Sham-operated FVB.Igf ϩ / Ϫ and nontransgenics consisted of 5 and 18 animals each at 1.5 and 2.5 mo of age. All mice were injected intraperitoneally with 10 g of monoclonal antibody specific for cardiac myosin (clone CCM-52) 24 h before death (19,20).…”

Isoproterenol-induced myocardial fibrosis in relation to myocyte necrosis.

“…34 Monoclonal antimyosin is specific for myocytes with permeable sarcolemma and remains active in the circulation for more than a week. Rather than being the sole result of a passive entry of the probe into the injured cell, the antibody is concentrated by binding to myofibrillar myosin.…”

“…Intact, uninjured cells exclude the antibody and remain unlabeled. 34 Both isoproterenol-treated and control rats were treated with 1 mg immunoglobulin G (IgG) fraction of monoclonal antibody CCM-52 intraperitoneally 24 hours before removal of heart. Animals killed less than 24 hours after isoproterenol treatment were pretreated with antimyosin.…”

“…After cryostat sectioning of the heart, the sections were stained with fiuorescein isothiocyanate (FITC)-conjugated rabbit anti-mouse IgG (Cappel Laboratories, Cochranville, Pennsylvania) to localize myocardial cells that bind antimyosin monoclonal antibody. 34 Immunofluorescent staining was evaluated with a microscope (Carl Zeiss, Thornwood, New York) equipped with epifluorescent optics optimized for FITC fluorescence.…”

Durchblutungsstörungen des Myokard

“…B. nach Lv. Injektion der Antikorper in histologischen Praparaten in der Infarktrandzone nachweisen (NOLAN et al 1983).…”