Mast cell stabilization improves cardiac contractile function following hemorrhagic shock and resuscitation

Hemorrhagic shock (HS) is associated with cardiac contractile dysfunction. Mast cell (MC) degranulation is hypothesized to mediate the cardiodepressant effect. Cardiac function was assessed after HS and resuscitation (HS/R) with the administration of the MC stabilizers to prevent MC degranulation. Anesthetized male Sprague-Dawley rats were randomized to sham-operated control or HS/R groups and underwent 60 min of HS followed by 2 h of resuscitated reperfusion. Animals in the HS/R groups were randomized to receive cromolyn (5 mg/kg), ketotifen (1 mg/kg), or saline 15 min before shock. Hearts were excised following HS or 2 h of reperfusion, and function was assessed on a Langendorff apparatus. A second group of randomized animals had serial blood samples taken to assess MC degranulation by quantifying levels of serum beta-hexosaminidase. Hearts were excised at 0 min (before HS) and following 60 min of HS (before resuscitation) for a histological evaluation of MC density and degranulation. In vivo MC stabilization using ketotifen and cromolyn improved cardiac peak systolic pressure (P < 0.05), contractility (P < 0.05), and relaxation (P < 0.05) compared with that of HS controls. Serum beta-hexosaminidase increased during HS/R and was inhibited by MC stabilization (P < 0.05). Degranulation was inhibited when assessed by histochemistry and immune fluorescence. The inhibition of MC degranulation can significantly improve cardiac function following HS/R.     

Reconstitution of the GalP galactose transport activity of Escherichia coli into liposomes made from soybean phospholipids

Galactose transport activity from Escherichia coli was solubilized with octyl glucoside, and reconstituted into liposomes made from soybean or E. coli lipid. Galactose counterflow in the proteoliposomes was inhibited by glucose, talose, 2-deoxygalactose and 6-deoxygalactose, confirming that it was due to GalP and not one of the other E. coli galactose transport systems.     

Mesenteric lymph from rats with trauma-hemorrhagic shock causes abnormal cardiac myocyte function and induces myocardial contractile dysfunction

Myocardial contractile dysfunction develops following trauma-hemorrhagic shock (T/HS). We have previously shown that, in a rat fixed pressure model of T/HS (mean arterial pressure of 30-35 mmHg for 90 min), mesenteric lymph duct ligation before T/HS prevented T/HS-induced myocardial contractile depression. To determine whether T/HS lymph directly alters myocardial contractility, we examined the functional effects of physiologically relevant concentrations of mesenteric lymph collected from rats undergoing trauma-sham shock (T/SS) or T/HS on both isolated cardiac myocytes and Langendorff-perfused whole hearts. Acute application of T/HS lymph (0.1-2%), but not T/SS lymph, induced dual inotropic effects on myocytes with an immediate increase in the amplitude of cell shortening (1.4 ± 0.1-fold) followed by a complete block of contraction. Similarly, T/HS lymph caused dual, positive and negative effects on cellular Ca2? transients. These effects were associated with changes in the electrophysiological properties of cardiac myocytes; T/HS lymph initially prolonged the action potential duration (action potential duration at 90% repolarization, 3.3 ± 0.4-fold), and this was followed by a decrease in the plateau potential and membrane depolarization. Furthermore, intravenous infusion of T/HS lymph, but not T/SS lymph, caused myocardial contractile dysfunction at 24 h after injection, which mimicked actual T/HS-induced changes; left ventricular developed pressure (LVDP) and the maximal rate of LVDP rise and fall (±dP/dt(max)) were decreased and inotropic response to Ca2? was blunted. However, the contractile responsiveness to β-adrenergic receptor stimulation in the T/HS lymph-infused hearts remained unchanged. These results suggest that T/HS lymph directly causes negative inotropic effects on the myocardium and that T/HS lymph-induced changes in myocyte function are likely to contribute to the development of T/HS-induced myocardial dysfunction.     

Changes in cardiac contractile function and myocardial

Cutaneous burn trauma causes cardiac contraction and relaxation defects, but the mechanism is unclear. Previous studies suggest that burn-related changes in myocyte handling of calcium may play an important role in postburn cardiac dysfunction. With the use of a high dissociation constant (K(d)) calcium indicator 1,2-bis(2-amino-5,6-difluorophenoxy)-ethane-N,N,N',N'-tetraacetic acid (TF-BAPTA) and (19)F NMR spectroscopy, this study examined the correlation between the changes in cytosolic free calcium concentration ([Ca(2+)](i)) and cardiac function after burn trauma. Sprague-Dawley rats were given scald burn (over 40% of the total body surface area) or sham burn. Twenty-four hours later, the hearts were excised and perfused by the Langendorff method with a modified phosphate-free Krebs-Henseleit bicarbonate buffer. Left ventricular (LV) developed pressure (LVDP), calculated from peak systolic LV pressure and LV end-diastolic pressure, was assessed through a catheter attached to an intraventricular balloon. At the same time, (31)P and (19)F NMR spectroscopy was performed before and after TF-BAPTA loading. LVDP measured in hearts from burned rats was <40% than that measured in hearts from sham burn rats (65 +/- 6 vs. 110 +/- 12 mmHg, P < 0.01); [Ca(2+)](i) was increased fourfold in hearts from the burned group compared with that measured in the sham burn group (0.807 +/- 0.192 vs. 3.891 +/- 0.929 microM). Loading TF-BAPTA in hearts transiently decreased LVDP by 15%. Phosphocreatine-to-P(i) ratio decreased, but ATP and intracellular pH remained unchanged by either TF-BAPTA loading or burn trauma. In conclusion, burn trauma impaired cardiac contractility, and this functional defect was paralleled by a significant rise in [Ca(2+)](i) in the heart.     

Reconstitution of the GalP galactose transport activity of Escherichia coli into liposomes made from soybean phospholipids

Galactose transport activity from Escherichia coli was solubilized with octyl glucoside, and reconstituted into liposomes made from soybean or E. coli lipid. Galactose counterflow in the proteoliposomes was inhibited by glucose, talose, 2-deoxygalactose and 6-deoxygalactose, confirming that it was due to GalP and not one of the other E. coli galactose transport systems.     

Disorders of the heart contractile function in chronic hemolytic anemia and their prevention

The coronary blood flow and heart contractile function were studied on rats with phenylhydrazine-induced chronic hemolytic anemia. The coronary blood flow in the animals' hearts was increased 2.5-fold, whereas the main parameters of contractile function were reduced but insignificantly. After the coronary blood flow dropped to the control level, the pressure and contraction rate fell by 40% and the relaxation rate diminished 2-fold. Thus, the enhanced coronary blood flow in the hearts of animals with hemolytic anemia appears to be a factor that compensates for the maintenance of myocardial contractility at the subnormal level. Administration of the antioxidant ionol, an inhibitor of lipid peroxidation, coupled with phenylhydrazine did not prevent the development of anemia but made the coronary blood flow descend in the hearts of anemic animal only by 80%. Since the iron-containing products of red cell dissolution activate lipid peroxidation during hemolytic anemia, this might play a role in the occurrence of heart muscle injuries. It is suggested that ionol prevents such injuries to a considerable extent, thereby preventing the development of compensatory enhancement of the coronary blood flow and heart contractile function disturbances during its normalization.     

Effect of liposomes on lipid peroxidation and total phospholipids in rabbit ischemic spinal cord model

The effect of spinal cord ischemia (induced by abdominal aorta ligation for 20 minutes) on lipid peroxidation and TPL composition was investigated and discussed in our previous articles. It is known, that partially reduced species of oxygen can be formed under aerobic conditions. For that reason, the effect of ligation release for 60 minutes was observed in experimental animals treated with the selected liposomes. Administration of CP, (CP+SA) and (CP+Chol) liposomes applied 30 minutes before 20 minutes ischemia revealed an ameliorating effect on in vivo and in vitro Fe-dependent peroxidation manifested by TBA-RS accumulation. Combined use of (CP+SA) liposomes with lipophylic form of stobadine (DP 1031) was not more effective. Application of CP liposomes directly before the ligation release slightly increased the antiradical capacity in spinal cord homogenates comparing with not-treated animals. Accumulation of TBA-RS was accompanied by TPL degradation during recirculation period but values of TPL after liposomal treatment were unaffected.     

Pharmacological correction of the disorders of cardiac contractile function in stress

It has been established that sodium hydroxybutyrate, prolactin, propranolol and ionol are capable of preventing the depression of the contractile function of the heart and of decreasing the glycogen level in the myocardium, provoked by emotional stress.     

The protective effect of preparations made from plant seedlings in experimental Pseudomonas aeruginosa infection

The influence of preparations obtained from oat and wheat seedlings (immunostimulating factors IF-1 and IF-2, respectively) on the natural resistance of mice to P. aeruginosa infection was studied. IF-1 and IF-2 were introduced intraperitoneally in a single injection in doses of 100 micrograms and 1000 micrograms per mouse 2 and 7 days prior to the inoculation of P. aeruginosa strain 8 in doses of 1 and 10 LD50. The presence of substances capable of stimulating the immunobiological reserves of the body in actively growing plants (seedlings) was shown.     

Cell death caused by selenium deficiency and protective effect of antioxidants

Selenium is an essential trace element and it is well known that selenium is necessary for cell culture. However, the mechanism underlying the role of selenium in cellular proliferation and survival is still unknown. The present study using Jurkat cells showed that selenium deficiency in a serum-free medium decreased the selenium-dependent enzyme activity (glutathione peroxidases and thioredoxin reductase) within cells and cell viability. To understand the mechanism of this effect of selenium, we examined the effect of other antioxidants, which act by different mechanisms. Vitamin E, a lipid-soluble radical-scavenging antioxidant, completely blocked selenium deficiency-induced cell death, although alpha-tocopherol (biologically the most active form of vitamin E) could not preserve selenium-dependent enzyme activity. Other antioxidants, such as different isoforms and derivatives of vitamin E, BO-653 and deferoxamine mesylate, also exerted an inhibitory effect. However, the water-soluble antioxidants, such as ascorbic acid, N-acetyl cysteine, and glutathione, displayed no such effect. Dichlorodihydrofluorescein (DCF) assay revealed that cellular reactive oxygen species (ROS) increased before cell death, and sodium selenite and alpha-tocopherol inhibited ROS increase in a dose-dependent manner. The generation of lipid hydroperoxides was observed by fluorescence probe diphenyl-1-pyrenylphosphine (DPPP) and HPLC chemiluminescence only in selenium-deficient cells. These results suggest that the ROS, especially lipid hydroperoxides, are involved in the cell death caused by selenium deficiency and that selenium and vitamin E cooperate in the defense against oxidative stress upon cells by detoxifying and inhibiting the formation of lipid hydroperoxides.     

Scaffold stiffness affects the contractile function of three-dimensional engineered cardiac constructs

We investigated the effects of the initial stiffness of a three-dimensional elastomer scaffold--highly porous poly(glycerol sebacate)--on functional assembly of cardiomyocytes cultured with perfusion for 8 days. The polymer elasticity varied with the extent of polymer cross-links, resulting in three different stiffness groups, with compressive modulus of 2.35 ± 0.03 (low), 5.28 ± 0.36 (medium), and 5.99 ± 0.40 (high) kPa. Laminin coating improved the efficiency of cell seeding (from 59 ± 15 to 90 ± 21%), resulting in markedly increased final cell density, construct contractility, and matrix deposition, likely because of enhanced cell interaction and spreading on scaffold surfaces. Compact tissue was formed in the low and medium stiffness groups, but not in the high stiffness group. In particular, the low stiffness group exhibited the greatest contraction amplitude in response to electric field pacing, and had the highest compressive modulus at the end of culture. A mathematical model was developed to establish a correlation between the contractile amplitude and the cell distribution within the scaffold. Taken together, our findings suggest that the contractile function of engineered cardiac constructs positively correlates with low compressive stiffness of the scaffold.     

Involvement of Ca<Superscript>2+</Superscript> in the development of ischemic disorders of myocardial contractile function

The review addresses the role of Ca²⁺ ions in the development of ischemic disorders of myocardial contractility associated with changes in Ca²⁺ homeostasis in cardiomyocytes and mitochondrial Ca²⁺ overload. A special attention is paid to the analysis of intracellular signaling mechanisms activated during the development of ischemic and reperfusion injury of the myocardium.     

An EPR spin probe study of liposomes from sunflower and soybean phospholipids

Comparative properties of lecithin-based liposomes prepared from the mixed phospholipids of sunflower seeds, soybean and egg yolk were investigated by electron paramagnetic resonance (EPR) spectroscopy. For these investigations, stable nitroxide radicals, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 5,7-dimethyladamantane-1-carboxylate (DMAC-TEMPO), 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA) were used as spin probes. Binding of the spin probes to the liposome membranes resulted in a substantial increase of the apparent rotational diffusion correlation times. The EPR spectra of the incorporated nitroxides underwent temperature-dependent changes. For every spin probe, values of apparent enthalpy and entropy of activation were calculated from the temperature dependence of rotational diffusion correlation times via Arrhenius equation. In case of DMAC-TEMPO, the data point to differences between the phospholipid bilayer of liposomes derived from sunflower and soy lecithin, and some similarity between the sunflower and egg yolk liposomes. Anisotropic hyperfine interaction constants of DMAC-TEMPO and 16-DSA included in the liposomes have been analyzed and attributed to different micropolarity of the surroundings of the spin probes. The kinetics of EPR signal decay of DMAC-TEMPO in the presence of 2,2′-azobis(2-amidinopropane) suggest the better stability of the sunflower liposomes to lipid peroxidation as compared to the liposomes prepared from soy lecithin.     

Skeletal myoblasts transplanted in the ischemic myocardium enhance in situ oxygenation and recovery of contractile function

It is unclear whether oxygen plays a role in stem cell therapy. Hence, the determination of local oxygenation (Po(2)) in the infarct heart and at the site of transplantation may be critical to study the efficacy of cell therapy. To demonstrate this, we have developed an oxygen-sensing paramagnetic spin probes (OxySpin) to monitor oxygenation in the region of cell transplantation using electron paramagnetic resonance (EPR) spectroscopy. Skeletal myoblast (SM) cells isolated from thigh muscle biopsies of mice were labeled with OxySpin by coculturing the cells with submicron-sized (270 +/- 120 nm) particulates of the probe. Myocardial infarction was created by left coronary artery ligation in mice. Immediately after ligation, labeled SM cells were transplanted in the ischemic region of the heart. The engraftment of the transplanted cells and in situ Po(2) in the heart were monitored weekly for 4 wk. EPR measurements revealed the retention of cells in the infarcted tissue. The myocardial Po(2) at the site of SM cell therapy was significantly higher compared with the untreated group throughout the 4-wk period. Histological studies revealed differentiation and engraftment of SM cells into myotubes and increased incidence of neovascularization in the infarct region. The infarct size in the treated group was significantly decreased, whereas echocardiography showed an overall improvement in cardiac function when compared with untreated hearts. To our knowledge, this the first report detailing changes in in situ oxygenation in cell therapy. The increased myocardial Po(2) positively correlated with neoangiogenesis and cardiac function.     

Thermotropic behavior of liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and their mixtures

The thermotropic properties of multilamellar liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and several mixtures of these two lipids were studied with the application of excimer--forming optical probe pyrene and microcalorimetry. It was discovered that when the proportion of the egg yolk lecithin in the lipid mixture was raised the temperature of the main phase transition reduced. For all this, independent of the lipid mixture composition when the temperature was raised, apparently, polarity of pyrene microenvironment in the liposomes bilayers decreased. On the basis of the analysis of solidus and liquidus curves obtained from calorimetric studies of the lipid mixtures and bend points of Arrhenius anamorphose obtained during the pyrene excimer formation measurements some conclusions were made about the role of unmodified and hydrogenized egg yolk lecithin cluster formation in the determination of thermotropic properties of the liposomes from the above two lipids mixtures. High temperature phase transition discovered for the egg yolk lecithin while measuring the pyrene excimer formation is proposed to be closely connected with temperature-dependent changes in the organization of phospholipid heads on the interphase bilayer/H2O solution.     

The effect of stobadine on the copper-induced peroxidation of egg yolk phosphatidylcholine in multilamellar liposomes

Stobadine, (-)- cis-2,8-dimethyl-2 ,3,4,4a,5,9b-hexahydro-1H-pyrido-[4,3b]-indole, is a pyridoindole derivative with antioxidant, antiarrhytmic, neuroprotective, local anesthetic, alpha-adrenolytic, antihistaminic, myorelaxant and other pharmacodynamic effects. The antioxidant properties were tested in a model system of egg yolk phosphatidylcholine (EYPC) multilamellar liposomes. The lipoperoxidation was induced by adding Cu2+ ions and tert-butylhydroperoxide. The course of EYPC peroxidation was monitored spectrophotometrically for conjugated diene formation. We found that stobadine prolonged the lag phase and decreased the rate of peroxidation during the lag phase in a dose-dependent manner. Surprisingly, an increase in the rate of peroxidation was observed at low stobadine concentration in the propagation phase. The possible cause of prooxidative action of stobadine is discussed.     

The protective effect of isosteviol sodium on cardiac function and myocardial remodelling in transverse aortic constriction rat

Pathological hypertrophy contributes to heart failure and there is not quite effective treatment to invert this process. Isosteviol has been shown to protect the heart against ischaemia-reperfusion injury and isoproterenol-induced cardiac hypertrophy, but its effect on pressure overload-induced cardiac hypertrophy is still unknown. Pressure overload induced by transverse aortic constriction (TAC) causes cardiac hypertrophy in rats to mimic the pathological condition in human. This study examined the effects of isosteviol sodium (STVNa) on cardiac hypertrophy by the TAC model and cellular assays in vitro. Cardiac function test, electrocardiogram analysis and histological analysis were conducted. The effects of STVNa on calcium transient of the adult rat ventricular cells and the proliferation of neonatal rat cardiac fibroblasts were also studied in vitro. Cardiac hypertrophy was observed after 3-week TAC while the extensive cardiac dysfunction and electronic remodelling were observed after 9-week TAC. Both STVNa and sildenafil (positive drug) treatment reversed the two process, but STVNa appeared to be more superior in some aspects and did not change calcium transient considerably. STVNa also reversed TAC-induced cardiac fibrosis in vivo and TGF-β1-induced fibroblast proliferation in vitro. Moreover, STVNa, but not sildenafil, reversed impairment of the autonomic nervous system induced by 9-week TAC.     

The effect of different temperature regimens in reperfusion on the recovery of myocardial contractile function after hypothermic cardiac ischemia]

The changes of the contractile function of the heart and cAMP content in myocardium depending on the temperature conditions of reperfusion (28 degrees C, 32 degrees C, 37 degrees C) after 90 minutes of hypothermal ischemia have been investigated on isolated hearts of rats. The comparative analysis of the investigation results has shown that, after cooling a cardial muscle to 8-12 degrees C, reperfusion with initial temperature of perfusate of 32 degrees C promotes fast restoration of independent cardiac activity, does not cause formation of reperfusion contracture, normalizes processes of synthesis and cAMP utilization in cardiomyocytes.