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Biomedical subjects

V I Kapel'ko

Publications and source records attributed to V I Kapel'ko.

At least 19 recordsLinked to original sources
PubMed2006

[Variability of hemodynamic parameters and resistance to stress damage in rats of different strains].

Total power of heart rate variability and baroreflex sensitivity were significantly smaller in the August rats than in the Wistar rats, but adrenal and plasma catecholamine contents were considerably higher in the former ones. 1 hour after stress (30 min in cold water), plasma catecholamine was increased 2-fold in Wistar rats, while in August rats the adrenaline concentration increased only by 58% and the were no changes in noradrenaline content. At the same time, activation of catecholamine metabolism in the adrenal glands was similar in both groups. The oxidative stress induced by hydrogen peroxide depressed the contractile function of isolated heart in the August rats to a smaller extent as compared to Wistar rats, control ones and after the cold-water stress. This effect correlated with more pronounced stability ofantioxidant enzymes in the August rats. It seems that the greater resistance to stress damage in the August rats is mediated by enhanced power of defense mechanisms both at systemic and cellular levels.

Adrenal Cortex↗
PubMed2006

[Effect of ubiquinone on contractile function and antioxidant status of the myocardium in spontaneously hypertensive rats].

During the period of aging of spontaneously hypertensive rats (SHR) between 6 and 13 weeks the systolic arterial pressure increased from 131+/-2 up to 176+/-3 mm Hg while in the control group of WKY rats it reached 122+/-2 mmHg. The hypertension was combined with myocardial hypertrophy -- the relative weight of SHR heart was 24% higher. The contractile myocardial function of the isolated isovolumic heart of SHR group did not differ from WKY group in a wide range of coronary perfusion rates. During oxidative stress induced by 40-min intracoronary introduction of H(2)O(2) function of hypertrophied SHR hearts fell significantly deeper. This coincided with decreased myocardial activity of superoxide dismutase and glutathione peroxidase by 29-30%, and increased catalase activity by 18%. The rate of generation of active forms of oxygen (hydroxyl radicals HO(.-)) in mitochondria from SHR hearts was higher as compared with WKY. Thus, the development of hypertension was combined with decreased antioxidant protection of the myocardium. The addition of ubiquinone to drinking water (approximately 10 mg/kg/day) for 6 weeks did not affect arterial pressure level, but was associated with two times lesser degree of myocardial hypertrophy. The hearts of SHR that received ubiquinone differed from those not treated with ubiquinone by increased maximal level of myocardial contractile function, and by improved myocardial relaxability and distensibility. After administration of H(2)O(2), myocardial function of SHR was kept on higher level. That was combined with less myocardial oedema, better preservation of antioxidant enzymes and reduced rate of succinate-dependent generation of superoxide radicals in mitochondria from hearts of ubiquinone treated SHR. The results have shown, that administration of ubiquinone to rats with hereditary hypertension reduces degree of myocardial hypertrophy, improves functional properties of the myocardium, promotes effective protection of antioxidant enzymes and increases the resistance of the cardiac muscle to oxidative stress.

Animals↗
PubMed2005

[Effect of granulocyte-macrophage colony stimulating factor on the function and regeneration of myocardium in rats with experimental infarction].

To test the reparative capacity of stromal cells in myocardial infarction, rats were injected with granulocyte-monocyte-colony stimulating factor (GM-CSF) (leukomax), a cytokine known by its ability to raise a level of stromal cells in the blood, during first three days after coronary artery ligation. Only 10 of 17 rats (59%) survived 4 weeks in this group compared with 16 of 24 (67%) among rats not treated with leukomax. Echocardiographic and electromanometric studies showed that in both groups ventricular (LV) dilatation which developed during first hours after surgery persisted throughout 6-8 weeks and was combined with decreased ejection fraction and elevated LV end diastolic pressure. These alterations correlated with infarct size which varied from 0 to 28% of left ventricular weight in both groups. There were no statistically significant differences in functional and morphometric measurements between groups receiving and not receiving GM-CSF. However this result may be inconclusive due to small number of investigated animals and broad variation of ischemic zone size in each group.

Animals↗
PubMed2005

[Evolution of concept and metabolic basis of ischemic dysfunction of the myocardium].

Myocardial contractile function during acute as well as chronic ischemia is reduced due to activation of a number of metabolic energy protecting mechanisms. Their abolition during reperfusion, associated with oxidative stress and incomplete restoration of function may cause cellular apoptosis due to impairment of aerobic ATP resynthesis. Strategy of postischemic reperfusion of the heart should be based on the use of natural protective mechanisms providing preferential restoration of high energy phosphates. The state of mitochondria is decisive for survival or restoration of function of cells.

Humans↗
PubMed2004

Heart resistance to oxidative stress in rats of different genetic strains.

In August rats reperfusion after regional myocardial ischemia in situ or intracoronary administration of hydrogen peroxide less significantly suppressed contractile activity of the heart compared to Wistar rats. Activities of catalase and superoxide dismutase in the myocardium during reperfusion remained unchanged in August rats. In Wistar rats a profound inhibition of cardiac function was accompanied by a decrease in enzyme activity.

Animals↗
PubMed2004

[Protective effect of hydrophilic ubiquinone on cardiac muscle during oxidative stress].

AIM: To assess effects of long term administration of a natural antioxidant ubiquinone on isoproterenol induced myocardial injury. METHODS: Rats were given hydrophilic ubiquinone with water for 8 weeks. RESULTS: Long term use of ubiquinone did not affect myocardial ultrastructure and relative myocardial weight. The dose of isoproterenol used in this study exerted moderate damaging action evidenced by disappearance of glycogen from sarcoplasm, development of edema, and partial destruction of mitochondrial cristae. These effects were associated with lowering of maximal magnitude of contractile function of the isolated heart and augmentation of superoxide radicals release in perfusate. These changes (except disappearance of glycogen) were not present in hearts of ubiquinone fed rats. Compared with controls mitochondria isolated from hearts of ubiquinone fed rats had higher respiratory control and more than twice lower rate of superoxide generation. CONCLUSION: As damaging effects of isoproterenol are mediated by augmented generation of active forms of oxygen the results obtained allow to suggest that myocardium of ubiquinone fed animals is characterized by elevated power of the antioxidant system.

Animals↗
PubMed2004

[The regulatory role of oxygen radicals in myocardial cells].

The paper reviews participation of primary active forms of oxygen in the processes of regulation of intracellular metabolism. Action of the primary forms of oxygen upon the myocardium contractile function depends on their concentration: their moderate increase enhances the rate and strength of contractions whereas higher concentrations diminish the contraction strength by inhibiting Ca2+ inflow from without. For NO the latter effect might be compensated by absence of coronary vessels dilatation. The level of the active forms of oxygen in the cells is subsidiary to the antioxidant system, and loss of the latter's components might trigger the apoptosis process and, consequently, some diseases.

Animals↗
PubMed2002

[The protective action of ubiquinone at ischemia and reperfusion].

Effects of prolonged consumption of ubiquinone on myocardial injury caused by ischemia and reperfusion were studied in reperfused rat hearts. Wistar rats received lipophylic or hydrophilic forms of ubiquinone for 6-8 weeks with chow or water, respectively. Isolated isovolumic hearts with a constant volume latex balloon in the left ventricular cavity were subjected to total normothermic ischemia (25 min) and subsequent reperfusion (50 min). Time course of ischemic contracture and its level in both groups of ubiquinone treated animals were similar to those in controls. However recovery of left ventricular developed pressure after reperfusion was significantly better in both ubiquinone groups (54-/+9, 65-/+7, and 24-/+4 mm Hg in animals treated with lipophylic and hydrophylic ubiquinone and controls, respectively, p<0.01). As a result the developed pressure and heart rate product reflecting maximal aerobic capacity of the heart was also better restored. Both ubiquinone groups demonstrated absence of increased coronary tone that was characteristic for control animals. Mitochondria isolated from reperfused hearts of ubiquinone treated rats showed better preservation of structure and respiratory control. Rate of succinate-dependent generation of superoxide radicals determined with a spin trap TIRON in mitochondria from hearts of rats treated with hydrophylic ubiquinone (35-/+8 mmol O(2) /min/g) was approximately twice lower (p<0.05) than in control group (74-/+12 mmol O(2) /min/g) while the value in lipophylic ubiquinone group (48-/+9 mmol O(2) /min/g) did not differ significantly from the control. The results evidence that prolonged consumption of water-soluble ubiquinone increases resistance of rat myocardium to injuring action of reperfusion.

Animals↗
PubMed2002

[Isoproterenol induced changes of protein expression and myocardial ultrastructure].

AIM: To elucidate alterations in myocardial ultrastructure and protein expression caused by isoproterenol. METHODS: Biochemical, immunohistochemical and electron microscopic studies of rat myocardium were carried out 2 hours and 3 weeks after single injections of isoproterenol (50 and 10 mg/kg). Relative content of myospecific proteins (KRP - kinase-related protein, desmin), cytoskeletal proteins (tubulin, vinculin, and myosin light chain kinase - MLCK) and extracellular matrix protein, fibronectin, was determined by immunoblotting. RESULTS: In 2 hours after injection of 50 mg/kg of isoproterenol destruction of some cardiomyocytes, contracture of myofibrils, and mild edema of intercellular space occurred; the content of KRP decreased by l6%, and that of tubulin, vinculin and fibronectin - by 27-29%. Reduced level of these proteins and also of MLCK persisted until 3 weeks after injection and was associated with altered cardiomyocyte ultrastructure. Glycogen granules were sparse, mitochondria contained arrow-like inclusions characteristic for calcium overload, huge mitochondria connected by specialized intermitochondrial contacts were present. Enlarged intercellular space contained areas of fibrosis with increased amount of type I and II collagens and fibronectin. Lower dose of isoproterenol (10 mg/kg) did not cause noticeable damaging action in the acute period, but in 3 weeks thickening of extracellular matrix occurred accompanied by increases of KRP and tubulin contents (by 26-32% compared with control level). Similar rise in expression of these proteins, and also of MLCK was observed after addition of isoproterenol to culture of chicken cardiomyocytes. CONCLUSION: These results indicate that even single injection of isoproterenol causes long lasting structural alterations in cardiac muscle accompanied by increased expression of extracellular matrix proteins as well as sarcoplasmic proteins apparently involved in the hypertrophic response of the cardiomyocytes.

Adrenergic beta-Agonists↗
PubMed2002

[Effect of adriamycin on expression and content of myocardial structural and regulatory proteins].

The biochemical and morphological study of the cytoskeleton and extracellular matrix of rat heart was carried out after single injection of adriamycin (2.2 or 0.44 mg/kg). Hearts were taken for the study after 2 hours and 3 weeks after injection. The light and electronic microscopy, immunohistochemical determination of type I, III and IV collagens and fibronectin using specific antibodies were implied for morphological study; electrophoresis and immunoblotting were implied for the determination of the content of some proteins of cardiomyocytes (KRP or telokin, desmin, tubulin and vinculin), and extracellular matrix (fibronectin) and vascular smooth muscle cells (MLCK, myosin light chain kinase). Adriamycin injection in the dose 2.2 mg/kg which is close to therapeutic and known to alter intracellular membranes approximately in the half of cardiomyocytes, did not influence the relative volume and structure of collagen network but distinctly reduced the density of fibronectin-distribution. The content of tubulin, fibronectin, MLCK and KRP was significantly decreased by 18-24%, while contents of desmin and vinculin were changed insignificantly. After 3 weeks, an increased density and extension of collagen network indicating the development of diffuse fibrosis were observed. Contents of tubulin and KRP were increased above control level by 50 and 20%, respectively. Similar hyperrestitution of tubulin, fibronectin and KRP content by 15-25% was determined after smaller dose of adriamycin (0.44 mg/kg). Only content of MLCK out of proteins studied remained at lower level in both groups by 25-34%. Isolated chick embryo cardiomyocytes subjected to adriamycin responded by increased level of KRP expression by 20% in 4 days while the level of tubulin expression remained unchanged. Results showed that damage of cardiomyocytes and extracellular matrix after single injection of adriamycin in the dose close to therapeutic was followed by increased expression of some proteins of cytoskeleton and extracellular matrix. KRP seems to play active role in this reparative response while the steadily reduced level of MLCK expression may disturb the control of coronary vessels.

Animals↗
PubMed1999

[Early stage of cardiomyopathy: mechanisms of damage and compensation].

In an experimental model of cardiomyopathy in Syrian hamsters, four principal phases were identified: lesion, reparation, compensation, and decompensation. Calcium overload seems to be a leading pathogenic factor in the 1st phase. If the action of damaging factor persists, the reparation phase is incomplete, and the compensation of the cardiac contractile function occurs due to an altered protein composition in the cells and extracellular matrix.

Animals↗
PubMed1993

[Protective effect of 2,3-butanedione monooxime on ischemic myocardium of rats].

Effects of 2,3-butanedione monoxime (BDM), an ATPase inhibitor, on ischemia-reperfusion myocardial injury were examined in isolated working rat hearts perfused in vitro. Following cardiac arrest induced by cardioplegic solution, global ischemia was produced for 30 min. In untreated hearts, reperfusion for 45 min resulted in an incomplete recovery of cardiac pump function. When BDM was added to the cardioplegic solution up to 20 mM, the recovery of cardiac function was significantly improved average by 19%. This BDM effect can, presumably, reduce ATP losses during ischemia and like that improve recovery of cardiac function during reperfusion.

Adenosine Triphosphatases↗
PubMed1993

[Modifications to the solution for reperfusion of the ischemic heart].

Isolated working guinea pig hearts were subjected to 30-min total normothermic ischemia and 30-min reperfusion with modified Krebs solution to which various agents were added. The presence of glutamate in the solution resulted in better recovery of cardiac pump function and higher myocardial energy phosphate levels. Addition of phrelone, a calmodulin inhibitor, or adenosine and ribose did not improve pump function. The similar functional recovery was observed after addition of taurine instead of glutamate and their combination exerted even higher functional recovery while further addition of phosphocreatine was not so effective.

Animals↗
PubMed1992

[Metabolic and functional consequences of complete inhibition of creatine kinase by iodoacetamide in the perfused heart].

Treatment of perfused rat hearts with 0.5 mM iodoacetamide (IAAm) for 15 min at different workloads resulting in a nearly complete inhibition of creatine kinase (CK, 99%) was followed by a rapid decline of the phosphocreatine (PCr) level (30%) and a 2-fold increase of the P(i) level which then stabilized. Conversely, the ATP content started to drop monotonously at the beginning of the IAAm washout and reached 30% 90 min after the IAAm removal under medium load. Under low workload the ATP decay occurred at later periods. Neither the ADP-stimulated mitochondrial respiration in skinned fibers, nor the Ca(2+)-stimulated ATPase activity of myofibrils was affected by IAAm treatment. The sensitivity of the resting tension of skinned fibers to Ca2+ tended to a slight increase. The cardiac work index (PRP-pressure-rate product) decreased by 25%, while the end diastolic pressure (EDP) rose by 15 mm Hg when IAAm acted under medium load. In contrast, under low work these parameters were practically stable. The hearts poisoned with IAAm performed a two times lower maximal work and had reduced (by 35%) oxygen consumption rates. The efficiency of energy utilization for mechanical work decreased by 40%. The changes in PRP and EDP correlated with the cytosolic [ATP]/[ADP] ratio in such a way that the decrease in the latter was associated with a decrease in PRP and the elevation of EDP. These data suggest that the creatine kinase system is necessary for the effective translation of a high [ATP]/[ADP] ratio from the intermembrane space of mitochondria to the cytoplasm, myofibrils and ionic pumps. This provides a high level of mechanical work and good relaxation of the left ventricle and protects cytosolic adenine nucleotides from the breakdown.

Adenine Nucleotides↗
PubMed1992

[Functional significance of 2 pathways of energy transport in cardiomyocytes].

To study the relative roles of creatine kinase (CK) and adenylate systems in cardiac energy turnover, the effect of CK inhibitor, iodoacetamide- (IAA, 0.5 mM), and 2-deoxyglucose-(DOG, 2 mM) induced) 65% depletion of adenine nucleotides at slightly decreased CK flux was determined in isolated rat heart. Both substances did not substantially affect contractile parameters of the isovolumic heart. However, an augmentation of cardiac work induced by isoproterenol addition was feeble and transient in IAA-treated hearts while the response of DOG-treated hearts was well preserved. The cardiac failure after IAA treatment was associated with irreversible fall in myocardial ATP content as evidenced by 31P-NMR technique. Furthermore, these hearts were unable to perform cardiac pump function due to insufficient cardiac filling and distensibility. The DOG-treated hearts exhibited 50% reduction in the pump function and were able to increase their work in elevated resistance. The results suggest that CK pathway is extremely important for both full cardiac relaxation and maximal contractile function.

Adenosine Triphosphate↗
PubMed1991

[High functional activity of mitochondrial creatine kinase of the myocardium before ischemia is tied with the worst restoration of contractility after reperfusion].

Isolated Langendorff-perfused guinea pig hearts were arrested with a cardioplegic solution containing 10 mM phosphocreatine + 15 mM glutamate (PG group) or not containing them (control group). Total normothermic ischemia lasted 45 min followed by 30 min reperfusion. Mitochondrial respiration in the absence and presence of different concentrations of ADP and creatine was studied in biopsy samples after saponin treatment. The samples were taken before and after ischemia as well as after the reperfusion period. A slightly better relative recovery of developed pressure (RRDP) in PG group was associated with higher mitochondrial acceptor control ratio after reperfusion. When results in both groups were taken together, marked negative correlations between the preischemic mitochondrial indices (particularly, those related to creatine kinase activity) and RRDP were revealed. Relative changes in these indices after ischemia demonstrated tight positive correlations with RRDP. Thus, the hearts having higher functional activity of mitochondrial creatine kinase are more sensitive to ischemia, other conditions being equal.

Animals↗