Comparative study of pathomorphology of myocardial circulation under conditions of increased afterload of the left or right ventricles showed similar changes. All compartments of the coronary bed were plethoric, capillary blood stasis and perivascular edema, more pronounced in arterial vessels, were detected in both cases. These changes equally involved both ventricles and the ventricular septum. Significant differences consisted in local increase in the density of functioning capillaries. The increase was the maximum in hemodynamically overloaded ventricle and ventricular septum, presumably due to increase of their contractile activity. The density of functioning capillaries in the intact (vs. pressure overloaded) ventricle also increased, but to a lesser degree, which could be due to systemic neurohumoral effects. If increased afterload was complicated by the development of heart failure, circulatory disorders in the myocardium progressed. Significant increase in the density of functioning capillaries in all cardiac compartments indicated decreased vascular tone and exhaustion of coronary reserve. This was paralleled by a sharp arterial plethora in case of increased afterload of the left ventricle and sharp blood stasis in the microcirculatory bed in case of increased right ventricle afterload. Reduction of effective perfusion pressure in the presence of coronary dystonia can cause coronary insufficiency and myocardial ischemia in case of increased right ventricle afterload.
Structural changes in the myocardium under conditions of increased left and right ventricular afterload were studied using polarization microscopy and histological, histochemical, and stereological methods. Increased afterload not complicated by heart failure was characterized by low number of damaged cardiomyocytes (3.3-6.5%) and moderate structural changes in the ventricular myocardium (contractures of different severity). Increased afterload complicated by heart failure was characterized by high ratio of damaged cardiomyocytes (5.6-19.2%) and severe reversible (grade I and II contractures) and irreversible (grade III contractures and lump degradation of myofibrils) structural changes. Irreversible damage to most cardiomyocytes included plasmatic impregnation, which was most pronounced in the subendocardial layer of ventricles operating under conditions of increased afterload. Comparative study showed that increased left and right ventricular afterload induces similar pathomorphological changes in the contractile myocardium. Our results indicate that increased afterload to the right or left ventricle is accompanied by the development of stereotypical structural changes in the myocardium. Profound and severe disturbances can cause heart failure.
Effect of natural complex of cytokines with activity of IL-1, IL-2, IL-6, TNF, MIF, GTFβ on the structure and metabolism of contractile ventricular cardiomyocytes was assessed in the control and under conditions of acute experimental aortic stenosis. Systemic administration of the complex in the control had no significant effect on myocardial morphology with low number of damaged cardiomyocytes and low degree of structural damage. Administration of the cytokine complex against the background of aortic stenosis did not exert any additional alterative effect on cardiomyocytes, structural damage of contractual nature was moderate. Systemic administration of the natural cytokine complex had a pronounced inhibitory effect on metabolic processes in the myocardium of both ventricles both in the control and against the background of increased hemodynamic load. In cardiomyocytes, glycolysis and citric acid cycle were slowed down, oxidation of free fatty acids and their metabolic products was inhibited as well as shuttle mechanisms and biosynthetic reactions. Inhibition of energy-producing processes is the cause of the lack of the contractile function energy supply and can worsen the course of cardiovascular diseases and increase the risk of their complications in conditions, accompanied by increased blood cytokine level.
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