Histoenzymological Characteristics of Smooth Muscle Cells in Myocardial Vessels: A Comparative Study under Conditions of Increased Left or Right Ventricular Afterload.

Histoenzymological methods were used to study metabolism of smooth muscle cells of intramural myocardial arteries during experimental aortic or pulmonary artery stenosis. Aortic stenosis was accompanied by changes in smooth muscles of the left ventricle manifested by deceleration of tricarboxylic acid cycle, inhibition of oxidation of free fatty acids and their metabolites, flux redistribution in the glycolytic cascade, and inhibition of shuttle systems and biosynthetic processes. Similar metabolic alterations were observed in vessels of the ventricular septum, but they were not revealed in vessels of the right ventricle (except glycolysis stimulation). Under conditions of pulmonary artery stenosis, histoenzymological alterations in vascular smooth muscle of both ventricles and ventricular septum were similar, which attested to acceleration of tricarboxylic acid cycle, stimulation of oxidation of the free fatty acids with their metabolites, acceleration of glycolysis, and activation of the shuttle systems and biosynthetic processes. Comparative analysis of histoenzymological alterations revealed substantial differences in the character of metabolic changes under conditions of increased left and right ventricular afterload, which can be caused by peculiarities in myocardial blood flow, severity of circulatory disorders, severity of hypoxia, and intensity of processes maintaining ionic homeostasis in vascular smooth muscles and transport across the histohematic barriers. The data attest to important metabolic role of glycolysis in vascular smooth muscles of the myocardium, especially under conditions of enhanced afterload of the right ventricle.

Histoenzymological characteristics of the heart conduction system: comparative study with left or right ventricle afterload.

Histoenzymological changes, indicating inhibition of the main metabolic processes, were found in the conduction cardiomyocytes of the left ventricle and ventricular septum in experimental stenosis of the aorta. The histoenzymological changes in the conduction system of both ventricles and ventricular septum were similar in experimental stenosis of the pulmonary artery and indicated primarily activation of glycolysis. The histoenzymological profile of conduction cardiomyocytes differed little in cases when the increase of the pressure load was complicated or not complicated by the development of heart failure, particularly in pulmonary artery stenosis. The histoenzymological changes in the conduction system in response to increased afterload differed significantly from those in the contractile myocardium and correlated with the level of cellular functional activity and sensitivity to the regulatory and alterative exposure. These data attest to minor role of metabolic shifts in conduction cell injuries with increasing afterload, primarily, of the right ventricle.

Histoenzymology of the contractile myocardium in experimental pulmonary stenosis.

Metabolism of contractile cardiomyocyte in experimental pulmonary stenosis complicated or not complicated by heart failure was studied by histochemical methods. In pulmonary stenosis not complicated by heart failure, intensification of glycolysis, more intense oxidation of free fatty acids and their metabolites, and acceleration of the citric acid cycle were found in the contractile cardiomyocytes. In pulmonary stenosis complicated by heart failure, glycogen content in the myocardium was sharply decreased. The histochemical enzyme profile of contractile cardiomyocytes is similar in pulmonary stenosis with and without heart failure. Comparative analysis of changes occurring in acute increase in afterload of the left or right ventricle suggested that in the latter case, metabolic abnormalities in the contractile cardiomyocytes are relatively unimportant in the pathogenesis of heart failure.

Histoenzymological characteristics of the contractile myocardium in experimental stenosis of the aorta.

Contractile cardiomyocyte metabolism was studied by histochemical methods in experimental stenosis of the aorta complicated and not by heart failure. Acceleration of the citric acid cycle, more intense oxidation of free fatty acids and their metabolites, glycolysis intensification, and higher activity of shuttle mechanisms were found in the contractile cardiomyocytes in stenosis of the aorta not complicated by heart failure. The presence of these metabolic shifts in the myocardium of all studied compartments suggests their association with not only more intense heart work, but also with the effects of total systems neurohumoral factors. Comparative study of myocardial metabolism in two variants of experimental stenosis of the aorta has revealed changes prognostically unfavorable for the development of heart failure. These changes include exhaustion of glycogen reserve, glycolysis inhibition, and metabolism shift towards biosynthetic processes. These data indicate an important role of glycolysis in support of myocardial contractile function during the acute phase of pressure overloading of the heart.

Pathomorphology of the heart conduction system: comparative study during increase in left or right ventricular afterload.

Pathomorphology of the peripheral compartments of the heart conduction system under conditions of increased left or right ventricular afterload is characterized by interstitial edema, hemorrhages, and reversible and irreversible focal lesions. The percentage of damaged conduction cardiomyocytes increases in the wall of hemodynamically overloaded ventricle and in the ventricular septum. These changes are more pronounced in cases when the afterload increase is complicated by heart failure development. Acute dilatation of the heart and distention of the myocardium are events of great specific significance in the genesis of the conduction system disorders developing under conditions of increased right ventricular afterload in comparison with those developing under conditions of increase left ventricular afterload. These data attest the presence of a pathomorphological base for the appearance of arrhythmias during the acute phase of pressure overload of the heart, especially in cases when it is aggravated by heart failure.

Use of polytetrafluorethylene films for closing of abdominal cavity under conditions of experimental peritonitis.

Four variants of polytetrafluorethylene films differing by size of micropores and manufacturing technology were used for closing of the abdominal cavity under conditions of experimental peritonitis in rats. The results of tensiometry and planimetry helped us to select the optimal variant of polytetrafluorethylene film characterized by sufficient strength, minimum size of micropores, and causing minimum complications.