[The Action of Apelin-12 and Its Analog on Hemodynamics and Cardiac Contractile Function of Rats With Isoproterenol-Induced Myocardial Lesion].

Introduction of isoproterenol (beta-adrenoreceptor agonist) into rats is one of the widespread experimental models of heart failure. It is caused by diffuse ischemic damage of cardiomyocytes, followed by development of substitutive fibrosis. Apelin is a natural regulator of the myocardial contractility. The effects of apelin molecule fragment, apelin-12 and its more stable synthetic analogue, apelin-12-2 on cardiac contractile function of rats with isoproterenol-induced myocardial lesion (IML) and control animals has been studied in this work using invasive (catheterization of the left ventricle) and non-invasive (echocardiography and impedansometry) methods. Infusion of both peptides was made by sequentially increasing rate from 0.5 to 50 µg/kg/min. In the control group, efficacy of apelin-12 was low while apelin-12-2 moderately but significantly increased indices of myocardial contractility and relaxability. These changes were more pronounced in rats with IML and, in addition, the heart rate and LV systolic pressure increased in this group. These results correlate well with echocardiographic studies which showed increases of LV end diastolic volume, stroke volume and ejection fraction by 17-38%. These alterations are probably due to improved Ca2+ transport in cardiomyocytes, as in experiments on isolated cardiomyocytes both apelins have facilitated and improved Ca2+ removal from myoplasma. The results allow to conclude that apelin-12-2 seems to be a promising candidate for further development as a therapeutic agent in heart failure.

[Histological and ultrastructural characteristics of myocardium in heart failure].

Endomyocardial biopsies performed in patients with various forms of cardiomyopathies (CMP) and chronic myocarditis in the presence of heart failure identified changes indicative of reduction of functioning cardiomyocytes (CMC) at the account of their destruction, dedifferentiation and inefficient hypertrophy". Energy apparatus of CMC was represented by large masses of destructed small mitochondria. Myofibrils were driven to periphery of CMC and appeared atrophic. Products of catabolism (lipofuscin, autophagous vacuoles, protein conglomerates) were accumulated in CMC. This led to impairment of CMC main function - to exert contraction. Reduction of number of capillary vessels per unit of myocardial cross-section area was also found. Discussion of problems of morphogenesis of the observed changes and of pathogenetic treatment is presented in the article.

[The donor's heart 22 years after the orthotopic transplantation].

The orthotopic heart transplantation is an acknowledge method for the treatment of cardiomyopathies of various etiology. Specific vasculopathy of the transplanted heart is considered to be a significant problem of the long-term postoperative period and serves the reason of low 10-years survival rates (not more then 50%). The issue unites the experience of follow-up and intravital electronic microscopy of transplantated heart's biopsies from 20 patients. Previously unknown data can help the clarification of posttransplantational cardiomyopathy.

[Mechanisms of cardiac hystiocyte's aging and death under noncoronary cardiac diseases].

The study of endomyocardial biopsy of patients with different noncoranary diseases with dilated cardiomyopathy and heart failure has been carried out. Hypertrophy of cardiac hystiocyte (CH) with dead mitochondrion, accumulation of lipofuscin, myeline-like mass, vacuoles with remains of organoids and conglomeration of dead mitochondrion was in the all biopsies studied by the light and electron microscopy. The possible mechanism of aging and death of CH could be functional impairment of lysosomal-autophagic and ubiquitin-proteosomal systems of CH and exocytosis. These changes probably are a crucial stage in the development of dilated cardiomyopathy and heart failure.

[Acute and postponed action of adriamycin on the contractile function and antioxidant status of the myocardium].

Functional, biochemical and morphological studies of rat cardiac muscle after single injection of adriamycin (2.2 mg/kg) were carried out. The myocardium was taken for studies in 2 hours and in 2-3 weeks after adriamycin injection. The isolated heart was perfused retrogradely with Krebs solution and left ventricular isovolumic pressure and perfusion pressure were continuously monitored. Two-fold increase in perfusion rate was accompanied by raised developed pressure, heart rate and perfusion pressure which in the given conditions reflected a tone of coronary vessels. The cardiac contractile function of rats that received adriamycin 2 hours before, remained unaltered as compared to control group, however, perfusion pressure was raised by 26%. These hearts responded to H2O2 introduction (100 microM) into coronary vessels by more profound fall in developed pressure, which fell to 31 +/- 8% after 40 minutes vs. 61 +/- 5% in the control group (p<0.01). In two-three weeks after adriamycin injection, both cardiac contractile function and its responsiveness to oxidative stress induced by H2O2 introduction did not differ from the control, however, perfusion pressure remained elevated and this was accompanied by slowed myocardial relaxation. The myocardial concentration of malonic dialdehyde was moderately increased in adriamycin-treated group in both terms while the activity of antioxidant enzymes (SOD, GPHx and catalase) remained unaltered. Results showed an absence of the direct connection between myocardial antioxidant status and the contractile function changes at adriamycin action.

[Cardiomyocytic dedifferentiation, "hibernation", and apoptosis are possible factors of progressive diabetic cardiomyopathy].

The study of endomyocardial biopsy specimens from patients with cardiomyopathies in the presence of insulin-independent diabetes mellitus and ultrathin sections has indicated that in addition to hypertrophy of cardiomyocytes (CMCs), interstitial sclerosis, interstitial adipose tissue, and impairments in the microcirculatory bed, the myocardium exhibits interstitial sclerosis with uncoupled CMCs with a lower diameter and degenerative changes. The uncoupled CMCs display the signs of "hibernation", dedifferentiation and atopic degeneration; the neurotransmitters are also prone to apoptosis. It is suggested that these changes may serve as factors of progressive diabetic cardiomyopathy.

[Ultrastructural and immunohistochemical characteristics of the mechanism of cardiomyocytic death in arrhythmogenic dysplasia of the right ventricle].

Right ventricular endomyocardial biopsy specimens from patients clinically diagnosed as having arrhythmogenic dysplasia of the right ventricle underwent electron microscopic and immunohistochemical studies. Myocardial fibrous fatty dysplasia was found in the semi-thin sections. The TUNEL immunohistochemic test revealed apoptotic nuclei in the cardiomyocytes. In the binucleated and trinuclated cardiomyocytes, one or two nuclei might be apoptotic, one or two others nuclei being intact. Electron microscopy identified the stages of movement of cardiomyocytic nuclei to the cell periphery as well as nuclear extrusion outside the cardiomyocytes. The cardiomyocytes themselves displayed pronounced vacuolization, mitochondrial destruction, accumulation of lipid inclusions and lysosome-like masses, and myofibrillar destruction.

[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.

[Histological and ultrastructural characteristics of the recipients' myocardium 7-14 years after orthotopic transplantation of the heart (according to endomyocardial biopsy)]. / Gistologicheskaya i ul'trastruktunaya kharakteristika miokarda retsipientov cherez 7-14 let posle ortopicheskoi transplantatsii serdtsa (po dannym éndomiokardial'noi biopsii).

Light optic and electron microscopic studies were made of endomyocardial biopsies from the right ventricle of 8 patients who had undergone orthotopic transplantation of the heart 7-14 years ago. For this period rejection reaction was not typical, more marked were changes related to transplantation coronary disease and microcirculatory disorders: hibernation of cardiomyocytes (CMC), their apoptosis, interstitial fibrosis, dystrophic alterations of CMC. The results show the CMC pool may be resupplied with pluripotent (stem) cells as well as hibernating CMC which take part in the myocardial activity after myocardial circulation recovery by means of angioplasty and plasmapheresis.

Protection of rat myocardium by coenzyme Q during oxidative stress induced by hydrogen peroxide.

Ubiquinone Q(10) (coenzyme Q) is an important component of the mitochondrial electron transport chain and an antioxidant. The purpose of this work was to find out whether an increase in the level of coenzyme Q in the heart changes its maximal working capacity and resistance to oxidative stress. Male Wistar rats were treated with coenzyme Q (10 mg/kg body weight per day) for six weeks, and this increased its content in the myocardium by 63%. The myocardial content of malonic dialdehyde and activities of key antioxidant enzymes were unchanged, except nearly 2.5-fold decrease in the activity of superoxide dismutase. The maximal working capacity of the isolated isovolumic heart did not change, but under conditions of oxidative stress induced by 45-min infusion of hydrogen peroxide (70 micro M) into coronary vessels the contractile function of these hearts decreased significantly more slowly. This was associated with less pronounced lesions in the ultrastructure of cardiomyocytes and lesser disorders in the oxidative metabolism of mitochondria that suggested increased antioxidant protection of the myocardium.

[Apoptosis and hibernation of cardiomyocytes of periscar zone as factor of chronic cardiac aneurysm progression]. / Apoptoz i gibernatsiia kardiomiotsitov perirubtsovoi zony kak faktor progressirovaniia khronicheskoi anevrizmy serdtsa.

Tissue specimen from chronic aneurysms and adjacent myocardium obtained at aneurysmectomy and coronary bypass surgery from 46 patients were subjected to morphological study. Immunohistochemical methods and electronic microscopy were applied for detection of apoptosis and hibernation of cardiomyocytes in 11 cases and histochemical determination of activity of energetic enzymes succinate and lactate dehydrogenase was used in 5 cases. Cardiomyocytes from peri and intra scar layers of myocardium were found to be in a state of hibernation while some of them were in a state of apoptosis. Extent of apoptosis was different in aneurysms on different stages of organization. Number of altered cardiomyocytes was the greatest in immature aneurysms. Basing on these findings apoptosis of hibernating cardiomyocytes was suggested to be one of factors of expansion of sclerotic zone and aneurysm formation.

[Protective effect of hydrophilic ubiquinone on cardiac muscle during oxidative stress]. / Vliianie gidrofil'noi formy ubikhinona na serdechnuiu myshtsu pri okislitel'nom stresse.

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.

[The protective action of ubiquinone at ischemia and reperfusion]. / Zashchitnoe deistvie ubikhinona (koénzima Q(10)) pri ishemii i reperfuzii serdtsa.

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.

[Isoproterenol induced changes of protein expression and myocardial ultrastructure]. / Izmeneniia ékspressii belkov i ul'trastruktury serdechnoi myshtsy pod vliianiem izoproterenola.

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.

[Effect of adriamycin on expression and content of myocardial structural and regulatory proteins]. / Izmeneniia ékspressii strukturnykh i reguliatornykh belkov v miokarde pri deistvii adriamitsina.

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.

[A retrospective morphological analysis of endomyocardial biopsies of myocarditis patients]. / Retrospektivnyi morfologicheskii analiz éndomiokardial'nykh bioptatov bol'nykh miokarditom.

A repeated retrospective analysis of histoultrastructure of endomyocardial biopsies of patients with diagnosis of myocarditis and with various life span after manifestation of the first disease symptoms. The most unfavorable sign of prognosis is advanced myocardiocyte necrosis, alterative changes and the degree of interstitial cell reaction. Death of cardiocytes due to apoptosis was not typical for myocarditis and was observed only in several patients from the group with long survival. A new type of cardiomyocyte death--extrusion of the nucleus from the cell--was found in the group with low survival.

Tracer kinetics analysis of the extracellular spaces in saline perfused hearts.

BACKGROUND: Precise estimation of the cellular water content presupposes a correct definition of the water fraction in tissue extracellular space. Low molecular weight markers (LMM), such as sulphate ion and sucrose, are widely used to define extracellular space size despite indications that they penetrate the cell. In contrast, inulin, with molecular weight of about 5000, is commonly regarded as a cell impermeable extracellular marker. OBJECTIVES: To compare LMM with inulin as markers in determining extracellular space size. ANIMALS AND METHODS: The size of extracellular space in guinea pig hearts perfused with crystalloid solution (hydrated hearts) was determined morphometrically and by mathematical model analysis of washout kinetics of LMM ((35)SO(4), (14)C-sucrose) or (3)H-inulin. RESULTS: Morphometrically, the sizes of vascular and interstitial spaces in the hydrated hearts were estimated to be 102+/-8 mL/kg wet mass (wm) and 452+/-17 mL/kg wm, respectively. Comparable data were obtained from model simulation of tracer washout: 67 mL/kg wm for vascular space and 439 to 462 mL/kg wm for interstitial space. Tracer penetration into cellular water, as shown by model analysis, was 28% for LMM and, reported here for the first time, 18% for inulin. The observed edema was probably due entirely to fluid accumulation in the interstitial space. CONCLUSION: Intracellular penetration of LMM must be taken into account, especially in modern nuclear magnetic resonance spectroscopic methods of cellular water monitoring in isolated perfused hearts.

Mitochondria enter the nucleus (one further problem in chronic alcoholism).

Electron microscopy of cardiomyocytes of patients with hypertrophic and alcoholic cardiomyopathies revealed the presence of nuclei with mitochondria accumulated in their core. This was associated with chromatin displacement towards the core of the nucleus. No large-scale intermixing of the nuclear content with the cytosol was found, although in some sections there were disruptions in the nuclear envelop continuity. The entrance of mitochondria into the nucleus was modeled in rats that were given ethanol and the catalase inhibitor aminotriazole for 12 weeks. It is suggested that the entrance of mitochondria into the nucleus promotes both the attack of mitochondria by nuclear proteins and the attack of nuclear DNA and proteins by proteins of the mitochondrial intermembrane space.

Morphological patterns of death by myocytes in arrhythmogenic right ventricular dysplasia.

There are two forms of nuclear loss from eukaryotic cells: biochemical DNA degradation in apoptosis and nuclear extrusion from the cell body as seen in mammalian erythroblasts. In biopsies of right ventricular myocardium from 8 patients with arrhythmogenic right ventricular dysplasia (ARVD), we found not only a terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine triphosphate nick-end labeling (TUNEL)-positive nucleus in mononuclear myocytes, but also 1 or 2 TUNEL-positive nuclei in multinuclear myocytes. With electron microscopy, we found a nuclear dislocation to the cell periphery, followed by its extrusion into the extracellular space. Both the migration and extrusion of the nuclei of myocytes resemble the morphogenesis of human erythroblasts. Nuclear extrusion from myocytes may be another form of programmed cell death. In support of this possibility, we also found evidence of cytoplasmic degradation in right ventricular myocytes from our ARVD cases, a process similar to one often seen in developmental programmed cell death and differing from typical nuclear apoptosis. In our ARVD cases, we thus found several different patterns of cell death, all associated with initial preservation of the plasmalemma and avoidance of local inflammation. All these features may be different responses to common signals for selective non-necrotic (apoptotic) death of right ventricular myocytes.