glycogen and Reperfusion-Injury

Topics: Animals; Glucose; Glycogen; Humans; Insulin; Myocardial Ischemia; Myocardium; Reperfusion Injury

Temporary occlusion of liver blood supply for complex liver operation is common in liver surgery. However, hepatic vascular occlusion will undoubtedly impair liver function. This study was designed to elucidate the effect of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy.. Fifty-seven patients were randomly divided into an experimental group (n = 29) and a control group (n = 28). In the experimental group, patients were given high-concentration glucose intravenously during 24 h before the operation. The hepatic lesion was resected after portal triad clamping in the two groups. Noncancer liver tissue was biopsied to measure hepatic tissue ATP content and change of malondialdehyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed by using an automatic biochemical analysis apparatus before the operation and the first and fifth days after operation.. The mean hepatic vascular occlusion time in the experimental group was 19.21 +/- 4.54 min and in the control group it was 21.04 +/- 5.11 min. Hepatic tissue ATP content of the experimental group was significantly higher than that of the control group at the end of hepatic vascular occlusion (2.15 +/- 0.39 mumol/g wet tissue vs. 1.33 +/- 0.44, p < 0.01) and at the point of 1-h reperfusion (2.19 +/- 0.29 mumol/g wet tissue vs. 1.57 +/- 0.35, p < 0.01). There was significant difference in SOD activity between the two groups at the end of hepatic vascular occlusion (130.69 +/- 30.49 NU/mg pr vs. 97.83 +/- 26.23, p < 0.01) and at the point of 1-h reperfusion (139.55 +/- 39.88 NU/mg pr vs. 114.74 +/- 25.93, p < 0.01). Significant difference was shown in MDA content between the two groups at the end of hepatic vascular occlusion (3.02 +/- 0.30 nmol/mg pr vs. 3.99 +/- 0.49, p < 0.01) and at the point of 1-h reperfusion (3.81 +/- 0.69 nmol/mg pr vs. 5.75 +/- 1.17, p < 0.01). In addition, the liver function of the experimental group was significantly better than that of the control group the first and fifth days after the operation (p < 0.01).. Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver operation during which temporary occlusion of hepatic blood flow is necessary.

Topics: Adult; Female; Glycogen; Hepatectomy; Humans; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Malondialdehyde; Middle Aged; Reperfusion Injury; Superoxide Dismutase

To study the mechanism of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy.. Seventeen patients were randomly divided into experimental group (n=9) and control group (n=8). In the experimental group, patients were given high concentration glucose intravenously during 24 hours before operation. The hepatic lesion was resected after portal triad clamping in the two groups. Non-cancer liver tissue was biopsied to measure hepatic tissue ATP content and change of malondialdehyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed before operation and the first and fifth day after operation.. Hepatic tissue ATP content of the experimental group was significantly higher than that of the control group both at the end of hepatic vascular occlusion and the point of one-hour reperfusion. Besides, liver function of the experimental group was significantly better than that of the control group the first and fifth day after operation. There was significant difference in SOD activity or MDA content between the two groups at the end of hepatic vascular occlusion and at the point of one-hour reperfusion.. Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver operation, in which temporary occlusion of hepatic blood flow is necessary.

Topics: Adenosine Triphosphate; Constriction; Digestive System Surgical Procedures; Female; Glycogen; Humans; Liver; Liver Circulation; Male; Malondialdehyde; Middle Aged; Reperfusion Injury; Superoxide Dismutase

We previously showed that hindlimb ischemia-reperfusion (IR) enhanced glucose uptake in the liver through the activation of the parasympathetic nervous system. Although we suggested that the key glucose transporter (GLUT) in this hepatic glucose uptake was GLUT4 by western blotting, the molecular weight of GLUT4 was nearly the same as that of GLUT2, which is predominantly expressed in the liver. We primarily conducted a histological evaluation to determine whether IR specifically accelerates the overexpression of GLUT4, rather than GLUT2, in the hepatocytes in vitro and in vivo.. A total of 54 male C57BL/6J mice were used and subjected to 3 min hindlimb ischemia repeated three times with 3 min interval. Focusing on the area connecting portal and central veins, the GLUT4 and GLUT2 expression in the hepatocytes were examined by real-time PCR and immunohistochemically. Moreover, the alteration of GLUT4 and GLUT2 expression by acetylcholine in the primary hepatocytes were examined by immunofluorescence.. IR significantly upregulated the GLUT4, rather than GLUT2, expression in both mRNA and protein in the liver. Histological examination revealed marked glycogen storage in zone1, the periportal area, coincident with the enhanced GLUT4 immunoreactivity, in the IR-treated liver. Incubation of primary hepatocytes with acetylcholine induced the appearance of GLUT4 on the membrane peripheries.. The overexpression of GLUT4 on the membrane peripheries contributed to increasing glucose uptake found in IR-treated livers. This acceleration of glucose uptake via GLUT4 may induce marked glycogen storage in zone1 through energy production linked with increased glucose preference.

Topics: Animals; Cell Membrane; Gene Expression; Gene Expression Regulation; Glucose; Glucose Transporter Type 2; Glucose Transporter Type 4; Glycogen; Hepatocytes; Insulin; Ischemic Preconditioning; Liver; Male; Mice; Mice, Inbred C57BL; Reperfusion Injury

Astrocytic glycogen serves as an important glucose reserve, and its degradation provides extra support for neighboring neurons during energy deficiency. Salvianolic acid B (SAB) exerts a neuroprotective effect on reperfusion insult after cerebrovascular occlusion, but the effect of SAB on astrocytic glycogen and its relationship with neuroprotection are not completely understood. Here, we knocked down astrocyte-specific glycogen phosphorylase (GP, the rate-limiting enzyme in glycogenolysis) in vitro and in vivo and investigated the changes in key enzymes in glycogen metabolism by performing immunoblotting in vitro and immunofluorescence in vivo. Neurobehavioral and morphological assessments were conducted to uncover the outcomes during brain reperfusion. SAB accelerated astrocytic glycogenolysis by upregulating GP activity but not GP expression after reperfusion. Suppression of astrocytic glycogenolysis weakened SAB-mediated neuroprotection against the reperfusion insult. In addition, activation of glycogenolysis by SAB contributed to the survival of astrocytes and surrounding neurons by increasing antioxidant levels in astrocytes. Our data reveal that astrocytic GP represents an important metabolic target in SAB-induced protection against brain damage after cerebrovascular recanalization.

Topics: Animals; Antioxidants; Astrocytes; Behavior, Animal; Benzofurans; Cell Survival; Female; Glycogen; Glycogen Phosphorylase; Glycogenolysis; Ischemic Stroke; Male; Mice; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Reperfusion Injury

Objective To investigate the efficacy and mechanism of c-Jun N-terminal kinase (JNK) in boosting survival of oxygen glucose deprivation (OGD) rat neurons. Methods The cortex neurons from fetal rats were primarily cultured to prepare a model of OGD neurons in vitro, and the characteristic endpoints were filtered to intervene with JNK inducer anisomycin (AN), respectively. The cells were randomly divided into control group, solvent control group (a same volume of solvent DMSO was added into the culture medium of the OGD neuron), AN group (OGD neurons were treated with JNK inducer AN for 5 hours at the end of OGD). After that, Western blotting and immunofluorescence cytometry were respectively performed to detect the protein expressions in OGD neurons, including beclin 1, microtubule-associated protein 1 light chain 3 (LC3), B cell lymphoma 2 (Bcl2), caspase-3, P62, ubiquitin, cathepsin B and lysosomal associated membrane protein 1 (LAMP1). The cell activity was evaluated by CCK-8 assay, and the axon length was measured by IPP software. Results Activation of JNK significantly promoted the expressions of beclin 1, LC3, and Bcl2, and markedly reduced the content of beclin 1-Bcl2 complex and attenuated the expressions of P62 and ubiquitin. Meanwhile, the expressions of cathepsin B and LAMP1 were not obviously altered. In this way, the survival rate of OGD neurons was improved. Conclusion Activation of JNK exerts a neuroprotective effect by facilitating dissociation of beclin 1-Bcl2 and inducing a switch from apoptosis to autophagy in OGD neurons.

Topics: Animals; Apoptosis; Autophagy; Beclin-1; Cathepsin B; Cell Survival; Glucose; Glycogen; Neurons; Oxygen; Proto-Oncogene Proteins c-bcl-2; Rats; Reperfusion Injury; Solvents; Ubiquitin

Astrocytic glycogen works as an essential energy reserve for surrounding neurons and is reported to accumulate excessively during cerebral ischemia/reperfusion (I/R) injury. Our previous study found that accumulated glycogen mobilization exhibits a neuroprotective effect against I/R damage. In addition, ischemia could transform astrocytes into A1-like (toxic) and A2-like (protective) subtypes. However, the underlying mechanism behind accumulated glycogen mobilization-mediated neuroprotection in cerebral reperfusion injury and its relationship with the astrocytic A1/A2 paradigm is unknown.. Astrocytic glycogen phosphorylase, the rate-limiting enzyme in glycogen mobilization, was specifically overexpressed and knocked down in mice and in cultured astrocytes. The I/R injury was imitated using a middle cerebral artery occlusion/reperfusion model in mice and an oxygen-glucose deprivation/reoxygenation model in cultured cells. Alterations in A1-like and A2-like astrocytes and the expression of phosphorylated nuclear transcription factor-κB (NF-κB) and phosphorylated signal transducer and activator of transcription 3 (STAT3) were determined by RNA sequencing, immunofluorescence and immunoblotting. Metabolites, including glycogen, NADPH, glutathione and reactive oxygen species (ROS), were analyzed by biochemical analysis.. Here, we observed that astrocytic glycogen mobilization inhibited A1-like astrocytes and enhanced A2-like astrocytes after reperfusion in an experimental ischemic stroke model in vivo and in vitro. In addition, glycogen mobilization could enhance the production of NADPH and glutathione by the pentose phosphate pathway (PPP) and reduce ROS levels during reperfusion. NF-κB inhibition and STAT3 activation caused by a decrease in ROS levels were responsible for glycogen mobilization-induced A1-like and A2-like astrocyte transformation after I/R. The astrocytic A1/A2 paradigm is closely correlated with glycogen mobilization-mediated neuroprotection in cerebral reperfusion injury.. Our data suggest that ROS-mediated NF-κB inhibition and STAT3 activation are the key pathways for glycogen mobilization-induced neuroprotection and provide a promising metabolic target for brain reperfusion injury in ischemic stroke.

Topics: Animals; Animals, Newborn; Astrocytes; Brain Ischemia; Coculture Techniques; Female; Glycogen; Ischemic Stroke; Male; Mice; Mice, Inbred C57BL; Neuroprotection; Reactive Oxygen Species; Reperfusion Injury

Analyze the effects of ischemic postconditioning on skeletal muscle injury and apoptosis produced by partial ischemia and reperfusion in rats.. An experimental study was designed using 70 Wistar rats divided in 3 groups: Sham; Control-submitted to ischemia and reperfusion; and Postconditioning-submitted to ischemia and reperfusion with ischemic postconditioning. Subgroups (n = 10) were divided by duration of ischemia (4, 5, or 6 hr). A partial ischemia model using aortic clamping was used. The postconditioning protocol consisted of 3 cycles of clamping the aorta for 1 min and releasing for another minute. Skeletal muscle injury was evaluated by measuring serum levels of releasing cytoplasmic enzymes: aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and total creatine phosphokinase (CPK). Lipid peroxidation was evaluated by muscular levels of malondialdehyde (MDA). Energetic cell storage was evaluated by muscular glycogen levels. Apoptosis was evaluated analyzing the expression of caspase 3 and protein B-cell lymphoma 2 (Bcl-2) by immunohistochemistry.. AST levels in Sham group were 109.80 units/L, in Control subgroups were 4h 200.60 units/L/5h 392.30 units/L/6h 118.82 units/L, whereas in Postconditioning subgroups were: 4h 316.10 units/L/5h 268.40 units/L/6h 267.00 units/L. There was a 2-3-fold increase in Control and Postconditioning groups compared with Sham group (P = 0.003) There was no difference between groups with the same ischemic injury time. LDH, CPK, and MDA levels were similar in Sham, Control, and Postconditioning groups. Subgroups with the same ischemic injury time were also similar. Glycogen levels in Sham group were 0.629 mg%, in Control subgroups were 4h 0.323 mg%/5h 0.348 mg%/6h 0.183 mg%, whereas in Postconditioning subgroups were: 4h 0.443 mg%/5h 0.270 mg%/6h 0.324 mg%. Control and Postconditioning groups were decreased by half in relation with the Sham group (P = 0.002), with no difference between groups with the same ischemic injury time. For both caspase 3 and Bcl-2, the percentage of positive cells increased more than 2-fold in Control and Postconditioning groups when compared with Sham group (P < 0.001). The greater the ischemic injury time, the greater was the percent of positive cells (P < 0.0005), with no difference between subgroups with the same ischemic injury time.. Ischemic postconditioning had neither protective effect on skeletal muscle injury nor avoided apoptosis induction in rats submitted to partial ischemia and reperfusion.

Topics: Animals; Aorta; Apoptosis; Aspartate Aminotransferases; Biomarkers; Caspase 3; Constriction; Creatine Kinase; Glycogen; Ischemic Postconditioning; L-Lactate Dehydrogenase; Lipid Peroxidation; Male; Malondialdehyde; Muscle, Skeletal; Proto-Oncogene Proteins c-bcl-2; Rats, Wistar; Regional Blood Flow; Reperfusion Injury; Time Factors

Dietary restriction or reduced food intake was supported to protect against renal and hepatic ischemic injury. In this vein, short fasting was recently shown to protect in situ rat liver against ischemia-reperfusion. Here, perfused ex vivo instead of in situ livers were exposed to ischemia-reperfusion to study the impact of disconnecting liver from extrahepatic supply in energetic substrates on the protection given by short-term fasting.. Perfused ex vivo livers using short (18 h) fasted compared with fed rats were submitted to ischemia-reperfusion and studied for release of cytolysis markers in the perfusate. Energetic stores are differently available in time and cell energetic charges (ratio of adenosine triphosphate plus half of the adenosine diphosphate concentrations to the sum of adenosine triphosphate + adenosine diphosphate + adenosine monophosphate concentrations), adenosine phosphates, and glycogen, which were further measured at different time points in livers.. Short fasting versus feeding failed to protect perfused ex vivo rat livers against ischemia/reperfusion, increasing the release of cytolysis markers (potassium, cytochrome c, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase) in the perfusate during reoxygenation phase. Toxicity of short fasting versus feeding was associated with lower glycogen and energetic charges in livers and lower lactate levels in the perfusate.. High energetic charge, intracellular content in glycogen, and glycolytic activity may protect liver against ischemia/reperfusion injury. This work does not question how much the protective role previously demonstrated in the literature for dietary restriction and short fasting. In fact, it suggests that exceeding the energy charge threshold value of 0.3 might trigger the effectiveness of this protective role.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Caloric Restriction; Cytochromes c; Fasting; Female; Glycogen; L-Lactate Dehydrogenase; Liver; Potassium; Rats; Rats, Wistar; Reperfusion Injury; Time Factors

We show here that mice hypomorphic for hypoxia-inducible factor prolyl 4-hydroxylase-2 (HIF-P4H-2) (Hif-p4h-2 (gt/gt)), the main regulator of the stability of the HIFα subunits, have normoxic stabilization of HIF-1α and HIF-2α in their skeletal muscles. The size of the capillaries, but not their number, was increased in the skeletal muscles of the Hif-p4h-2 (gt/gt) mice, whereas the amount of glycogen was reduced. The expression levels of genes for glycolytic enzymes, glycogen branching enzyme 1 and monocarboxylate transporter 4, were increased in the Hif-p4h-2 (gt/gt) skeletal muscles, whereas no significant increases were detected in the levels of any vasculature-influencing factor studied. Serum lactate levels of the Hif-p4h-2 (gt/gt) mice recovered faster than those of the wild type following exercise. The Hif-p4h-2 (gt/gt) mice had elevated hepatic phosphoenolpyruvate carboxykinase activity, which may have contributed to the faster clearance of lactate. The Hif-p4h-2 (gt/gt) mice had smaller infarct size following limb ischemia-reperfusion injury. The increased capillary size correlated with the reduced infarct size. Following ischemia-reperfusion, glycogen content and ATP/ADP and CrP/Cr levels of the skeletal muscle of the Hif-p4h-2 (gt/gt) mice were higher than in the wild type. The higher glycogen content correlated with increased expression of phosphofructokinase messenger RNA (mRNA) and the increased ATP/ADP and CrP/Cr levels with reduced apoptosis, suggesting that HIF-P4H-2 deficiency supported energy metabolism during ischemia-reperfusion and protection against injury. Key messages: HIF-P4H-2 deficiency protects skeletal muscle from ischemia-reperfusion injury. The mechanisms involved are mediated via normoxic HIF-1α and HIF-2α stabilization. HIF-P4H-2 deficiency increases capillary size but not number. HIF-P4H-2 deficiency maintains energy metabolism during ischemia-reperfusion.

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Female; Gene Deletion; Gene Expression Regulation; Glycogen; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Inducible Factor-Proline Dioxygenases; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Protective Factors; Reperfusion Injury

To study at what temperature the oxygen carried by the perfusate meets liver requirements in a model of organ perfusion.. In this study, we correlated hypoxia inducible factor (HIF)-1α expression to the perfusion temperature and the hepatic oxygen uptake in a model of isolated perfused rat liver. Livers from Wistar rats were perfused for 6 h with an oxygenated medium at 10, 20, 30 and 37 °C. Oxygen uptake was measured by an oxygen probe; lactate dehydrogenase activity, lactate release and glycogen were measured spectrophotometrically; bile flow was gravitationally determined; pH of the perfusate was also evaluated; HIF-1α mRNA and protein expression were analyzed by real time-polymerase chain reaction and ELISA, respectively.. Livers perfused at 10 and 20 °C showed no difference in lactate dehydrogenase release after 6 h of perfusion (0.96±0.23 vs 0.93±0.09 mU/min per g) and had lower hepatic damage as compared to 30 and 37 °C (5.63±0.76 vs 527.69±45.27 mU/min per g, respectively, Ps<0.01). After 6 h, tissue ATP was significantly higher in livers perfused at 10 and 20 °C than in livers perfused at 30 and 37 °C (0.89±0.06 and 1.16±0.05 vs 0.57±0.09 and 0.33±0.08 nmol/mg, respectively, Ps<0.01). No sign of hypoxia was observed at 10 and 20 °C, as highlighted by low lactate release respect to livers perfused at 30 and 37 °C (121.4±12.6 and 146.3±7.3 vs 281.8±45.3 and 1094.5±71.7 nmol/mL, respectively, Ps<0.02), and low relative HIF-1α mRNA (0.40±0.08 and 0.20±0.03 vs 0.60±0.20 and 1.47±0.30, respectively, Ps<0.05) and protein (3.72±0.16 and 3.65±0.06 vs 4.43±0.41 and 6.44±0.82, respectively, Ps<0.05) expression.. Livers perfused at 10 and 20 °C show no sign of liver injury or anaerobiosis, in contrast to livers perfused at 30 and 37 °C.

Topics: Animals; Cold Temperature; Energy Metabolism; Glycogen; Hypoxia-Inducible Factor 1, alpha Subunit; In Vitro Techniques; L-Lactate Dehydrogenase; Lactic Acid; Liver; Male; Organ Preservation; Organ Preservation Solutions; Oxygen; Perfusion; Rats, Wistar; Reperfusion Injury; RNA, Messenger; Time Factors; Tissue Survival

Pyruvate is a key intermediary in energy metabolism and can exert antioxidant and anti-inflammatory effects. However, the fate of pyruvate during AKI remains unknown. Here, we assessed renal cortical pyruvate and its major determinants (glycolysis, gluconeogenesis, pyruvate dehydrogenase [PDH], and H2O2 levels) in mice subjected to unilateral ischemia (15-60 minutes; 0-18 hours of vascular reflow) or glycerol-induced ARF. The fate of postischemic lactate, which can be converted back to pyruvate by lactate dehydrogenase, was also addressed. Ischemia and glycerol each induced persistent pyruvate depletion. During ischemia, decreasing pyruvate levels correlated with increasing lactate levels. During early reperfusion, pyruvate levels remained depressed, but lactate levels fell below control levels, likely as a result of rapid renal lactate efflux. During late reperfusion and glycerol-induced AKI, pyruvate depletion corresponded with increased gluconeogenesis (pyruvate consumption). This finding was underscored by observations that pyruvate injection increased renal cortical glucose content in AKI but not normal kidneys. AKI decreased PDH levels, potentially limiting pyruvate to acetyl CoA conversion. Notably, pyruvate therapy mitigated the severity of AKI. This renoprotection corresponded with increases in cytoprotective heme oxygenase 1 and IL-10 mRNAs, selective reductions in proinflammatory mRNAs (e.g., MCP-1 and TNF-α), and improved tissue ATP levels. Paradoxically, pyruvate increased cortical H2O2 levels. We conclude that AKI induces a profound and persistent depletion of renal cortical pyruvate, which may induce additional injury.

Topics: Acute Kidney Injury; Adenosine Triphosphate; Animals; Gluconeogenesis; Glucose; Glycogen; Hydrogen Peroxide; Ischemia; Kidney Cortex; Kidney Tubules; Lactic Acid; Male; Mice; Pyruvate Dehydrogenase Complex; Pyruvic Acid; Reperfusion Injury

Fructose is a major diet component directly related to severe damages to the microcirculation and to diseases such as obesity, diabetes and hypertension to which physical activity is pointed out as an important non-pharmacological treatment since its positive effects precede anthropometric improvements. In this study we have investigated the effects of a light/moderate aerobic exercise training (AET) on microcirculatory dysfunction elicited by carbohydrate overload during a period of 5 months. Male hamsters (Mesocricetus auratus) whose drinking water was substituted (F) or not (C) by 10% fructose solution, during 20 weeks, associated or not to AET in the last 4 weeks (EC and EF subgroups) had their microcirculatory function evaluated on the cheek pouch preparation, glucose and insulin tolerance (GTT and ITT) tested. Arterial blood was collected for pO2, pCO2, HCO3(-), pH, total CO2, saturated O2 and lactate determinations. Liver fragments were observed using an electron microscope. Microcirculatory responses to acetylcholine [Ach, an endothelium-dependent vasodilator; 10(-8)M - *123.3±7.5% (C), 119.5±1.3% (EC), *98.1±3.2% (F) and 133.6±17.2% (EF); 10(-6)M - *133.0±4.1% (C), 135.6±4.3% (EC), *103.4±4.3% (F) and 134.1±5.9% (EF); 10(-4)M - *167.2±5.0% (C), 162.8±5.4% (EC), *123.8±6.3% (F) and 140.8±5.0% (EF)] and to sodium nitroprusside [SNP, an endothelium-independent vasodilator; 10(-8)M - 118.8±6.8% (C), 114.0±5.0% (EC), 100.2±2.9% (F), 104.9±4.4% (EF); 10(-6)M - 140.6±11.7% (C), 141.7±5.5% (EC), 125.0±4.7% (F), 138.3±2.8% (EF); 10(-4)M - 150.4±10.9% (C), 147.9±6.5% (EC), 139.2±7.3% (F), 155.9±4.7% (EF)] and macromolecular permeability increase induced by 30 min ischemia/reperfusion (I/R) procedure [14.4±3.5 (C), 30.0±1.9 (EC), *112.0±8.8 (F) and *22.4±0.9 leaks/cm(2) (EF)] have shown that endothelium-dependent vasodilatation was significantly reduced and I/R induced macromolecular permeability augmented in sedentary fructose (F) subgroup and both improved after AET. Electron microscopy analysis of the liver showed significant differences between exercised and sedentary subgroups with greater amount of glycogen in F subgroups compared to other ones. No significant changes on mean arterial pressure, heart rate or blood gase between subgroups could be detected. Our results point out that AET could normalize microcirculatory dysfunction elicited by long term substitution of drinking water by 10% fructose solution.

Topics: Animals; Biomarkers; Capillary Permeability; Cheek; Dietary Sucrose; Disease Models, Animal; Exercise Therapy; Glycogen; Liver; Male; Mesocricetus; Microcirculation; Microvessels; Reperfusion Injury; Time Factors; Vascular Diseases; Vasodilation; Vasodilator Agents

Transient carotid artery occlusion causes ischemia/reperfusion (I/R) injury resulting in neuron and pancreatic β-cell death with consequential post-stroke hyperglycemia, which can lead to diabetes and may accelerate the development of Alzheimer's disease. Antioxidants have been shown to protect against the I/R injury and destruction of neurons. However, it is unknown whether the protection against I/R injury extends to the pancreatic β-cells. Therefore, we investigated whether treatment with ebselen, a glutathione peroxidase mimic, prevents neuronal and β-cell death following I/R in gerbils susceptible to stroke. After 28 days post artery occlusion, there was widespread neuronal cell death in the CA1 of the hippocampus and elevated IL-1β and TNF-α levels. Pretreatment with ebselen prevented the death by 56% and attenuated neurological damage (abnormal eyelid drooping, hair bristling, muscle tone, flexor reflex, posture, and walking patterns). Ischemic gerbils also exhibited impaired glucose tolerance and insulin sensitivity which induced post-stroke hyperglycemia associated with decreased β-cell mass due to increased β-cell apoptosis. Ebselen prevented the increased β-cell apoptosis, possibly by decreasing IL-1β and TNF-α in islets. Ischemia also attenuated hepatic insulin signaling, and expression of GLUT2 and glucokinase, whereas ebselen prevented the attenuation and suppressed gluconeogenesis by decreasing PEPCK expression. In conclusion, antioxidant protection by ebselen attenuated I/R injury of neurons and pancreatic β-cells and prevented subsequent impairment of glucose regulation that could lead to diabetes and Alzheimer's disease.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Azoles; Brain Ischemia; Cell Survival; Cytokines; Gerbillinae; Glycogen; Hyperglycemia; Insulin; Insulin-Secreting Cells; Isoindoles; Liver; Male; Organoselenium Compounds; Random Allocation; Reperfusion Injury; Signal Transduction

Consecutive treatment of normal heart with a high dose of isoproterenol and adenosine (Iso/Ade treatment), confers strong protection against ischaemia/reperfusion injury. In preparation for translation of this cardioprotective strategy into clinical practice during heart surgery, we further optimised conditions for this intervention using a clinically-relevant dose of Iso and determined its cardioprotective efficacy in hearts isolated from a model of surgically-induced heart failure.. Isolated Langendorff-perfused rat hearts were treated sequentially with 5 nM Iso and 30 μM Ade followed by different durations of washout prior to 30 min global ischaemia and 2 hrs reperfusion. Reperfusion injury was assessed by measuring haemodynamic function, lactate dehydrogenase (LDH) release and infarct size. Protein kinase C (PKC) activity and glycogen content were measured in hearts after the treatment. In a separate group of hearts, Cyclosporine A (CsA), a mitochondria permeability transition pore (MPTP) inhibitor, was added with Iso/Ade. Failing hearts extracted after 16 weeks of ligation of left coronary artery in 2 months old rats were also subjected to Iso/Ade treatment followed by ischaemia/reperfusion.. Recovery of the rate pressure product (RPP) in Iso/Ade-treated hearts was significantly higher than in controls. Thus in Iso/Ade treated hearts with 5 nM Iso and no washout period, RPP recovery was 76.3±6.9% of initial value vs. 28.5±5.2% in controls. This was associated with a 3 fold reduction in LDH release irrespective to the duration of the washout period. Hearts with no washout of the drugs (Ade) had least infarct size, highest PKC activity and also showed reduced glycogen content. Cardioprotection with CsA was not additive to the effect of Iso/Ade treatment. Iso/Ade treatment conferred significant protection to failing hearts. Thus, RPP recovery in failing hearts subjected to the treatment was 69.0±16.3% while in Control hearts 19.7±4.0%. LDH release in these hearts was also 3 fold lower compared to Control.. Consecutive Iso/Ade treatment of normal heart can be effective at clinically-relevant doses and this effect appears to be mediated by glycogen depletion and inhibition of MPTP. This intervention protects clinically relevant failing heart model making it a promising candidate for clinical use.

Topics: Adenosine; Animals; Glycogen; Heart Failure; Hemodynamics; In Vitro Techniques; Isoproterenol; Male; Myocardium; Rats; Rats, Wistar; Reperfusion Injury

To investigate the protective effects of ischemic pre and postconditioning, as well as the association of both methods, in skeletal muscle injury produced by ischemia and reperfusion in rats.. An experimental study was designed using 40 Wistar rats divided in four groups (n=10): Control - rats submitted to ischemia for 240 minutes (min) and reperfusion for 60 min; Ischemic preconditioning (Pre) - animals submitted to three cycles of clamping and releasing the aorta for five min before being submitted to the ischemia/reperfusion procedure; Ischemic postconditioning (Post) - rats submitted to three cycles of clamping and releasing the aorta for one min after the 240-minute ischemic phase; Ischemic pre and postconditioning (Pre-post) - animals submitted to the same procedures of Pre and Post groups. Skeletal muscle injury was evaluated by measuring serum levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phosphokinase (CPK); and muscular levels of malondialdehyde (MDA) and glycogen.. AST levels were significantly higher in Pre and Pre-post groups (P<.01). There were no differences in LDH and CPK levels. Muscular MDA levels were similar. Glycogen levels were significantly higher in Pre and Pre-post groups (P<.01).. Both preconditioning and its association with postconditioning had a protective effect by avoiding glycogen depletion in skeletal muscle in rats submitted to ischemia and reperfusion. Association of pre and postconditioning did not show advantage compared to preconditioning alone. Postconditioning alone did not show protective effect.

Topics: Animals; Aspartate Aminotransferases; Creatine Kinase; Disease Models, Animal; Glycogen; Ischemic Postconditioning; Ischemic Preconditioning; L-Lactate Dehydrogenase; Male; Malondialdehyde; Muscle, Skeletal; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Reproducibility of Results; Time Factors

Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that directs many of the cellular responses to hypoxia. In these studies, we have used a mouse model containing a cardiac-specific, oxygen-stabilized, doxycycline (Dox)-off regulated HIF-1α transgene to probe the role of HIF-1α in cardioprotection. Hearts used in these studies were derived from wild-type (WT), noninduced (Non-I), and 2 day (2D) and 6 day (6D) Dox-deprived mice. Whereas HIF-1α protein is undetectable in WT mice, it is present in heart tissue of "noninduced" transgenic mice, presumably because of leakiness of the promoter construct. In mice denied Dox for 2 or 6 days, HIF-1α is overexpressed to a much greater extent than Non-I or WT animals, as expected. WT and HIF-1α-expressing hearts (Non-I, 2D and 6D induced) were subjected to 30 min of ischemia, and functional recovery was measured upon reperfusion. Recovery of preischemic left ventricular developed pressure was 14% for WT, 67% for Non-I hearts, 64% for 2D-induced, and 62% for 6D-induced hearts. 6D-induced HIF hearts have increased preischemic glycogen reserves, higher glycogen synthase protein levels, and significantly higher lactic acid release during ischemia. 6D-induced HIF hearts were also better able to maintain ATP levels during ischemia compared with WT and Non-I hearts. Interestingly, Non-I hearts showed no significant increase in glycogen reserves, glycolytic flux, or greater ATP preservation during ischemia and yet were protected to a similar extent as the 6D-induced hearts. Finally, the mitochondrial membrane potential of isolated adult myocytes was monitored during anoxia or treatments with cyanide and 2-deoxyglucose. HIF-1α expression was shown to protect mitochondrial polarization during both stress treatments. Taken together these data indicate that, while HIF-1α expression in heart does induce increases in compensatory glycolytic capacity, these changes are not necessarily required for cardioprotection, at least in this model of ischemic stress.

Topics: Animals; Blood Pressure; Cardiotonic Agents; Glycogen; Glycolysis; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Mice; Mice, Transgenic; Oxygen; Recovery of Function; Reperfusion Injury

The optimal regimen of preliminary ischemic preparation, in which the vessels occlusion causes minimal pathohistological hepatic changes without inhibition of its regeneration capacities, was studied in experiment. The ischemic-reperfusional damage of liver, using hepatoduodenal ligament crossclamping in various regimens, was modeled on 40 rabbits in a randomized experimental investigation. Morphological investigations of the animals liver fragments, taken immediately after ligament crossclamping and on the third postoperative day, were performed. There was established, that severity and reversibility of the hepatic tissue affection have differed, depending on the ischemia duration and reperfusion period. The vessels occlusion regimen with preliminary ischemic preparation was the most safe for hepatic tissue, without rude structural injuries and functional disorders, permitting to recommend it for clinical application as the optimal one while performance of hepatic resection in combination with afferent vascular exclusion.

Topics: Animals; Cytoplasm; Glycogen; Hepatectomy; Hepatocytes; Ischemic Preconditioning; Liver; Liver Regeneration; Rabbits; Reperfusion Injury

N-acetylcysteine (NAC) is an antioxidative molecule known to protect liver tissue from oxygen radical species generated during ischemia and reperfusion (IR). Nutritional and toxicology studies have shown that NAC also improves glucose metabolism and glycogen stores. We hypothesized that NAC improves glycogenesis and that impaired glycogenesis is a key element in IR injury.. In an experimental model, 80 min of segmental liver ischemia was induced in 16 pigs and the reperfusion was followed for 360 min. Eight animals received NAC 150 mg/kg as a bolus injection followed by an infusion of NAC 50 mg/kg/h intravenously.. AST and leukocyte density were lower in the NAC-treated animals, unrelated to the glutathione levels or apoptosis. Glycogen stores returned to a higher degree in the NAC-treated animals and microdialysis revealed lower levels of lactate during the reperfusion phase. Nitrite/Nitrate levels in the NAC group were lower in both serum and microdialysates, indicating that NAC scavenges radical nitrosative species.. NAC treatment improves glycogenesis after liver IR injury and reduces the level of intraparenchymal lactate during reperfusion, possibly due to the scavenging of radical nitrosative species.

Topics: Acetylcysteine; Adenosine Triphosphate; Analysis of Variance; Animals; Apoptosis; Aspartate Aminotransferases; Free Radical Scavengers; Glutathione; Glycogen; Lactic Acid; Leukocyte Count; Liver; Male; Microdialysis; Neutrophils; Nitrates; Nitrites; Reperfusion Injury; Swine

We previously demonstrated that hexokinase (HK) II plays a key role in the pathophysiology of ischemia-reperfusion (I/R) injury of the heart (Smeele et al. Circ Res 108: 1165-1169, 2011; Wu et al. Circ Res 108: 60-69, 2011). However, it is unknown whether HKII also plays a key role in I/R injury and healing thereafter in skeletal muscle, and if so, through which mechanisms. We used male wild-type (WT) and heterozygous HKII knockout mice (HKII(+/-)) and performed in vivo unilateral skeletal muscle I/R, executed by 90 min hindlimb occlusion using orthodontic rubber bands followed by 1 h, 1 day, or 14 days reperfusion. The contralateral (CON) limb was used as internal control. No difference was observed in muscle glycogen turnover between genotypes at 1 h reperfusion. At 1 day reperfusion, the model resulted in 36% initial cell necrosis in WT gastrocnemius medialis (GM) muscle that was doubled (76% cell necrosis) in the HKII(+/-) mice. I/R-induced apoptosis (29%) was similar between genotypes. HKII reduction eliminated I/R-induced mitochondrial Bax translocation and oxidative stress at 1 day reperfusion. At 14 days recovery, the tetanic force deficit of the reperfused GM (relative to control GM) was 35% for WT, which was doubled (70%) in HKII(+/-) mice, mirroring the initial damage observed for these muscles. I/R increased muscle fatigue resistance equally in GM of both genotypes. The number of regenerating fibers in WT muscle (17%) was also approximately doubled in HKII(+/-) I/R muscle (44%), thus again mirroring the increased cell death in HKII(+/-) mice at day 1 and suggesting that HKII does not significantly affect muscle regeneration capacity. Reduced HKII was also associated with doubling of I/R-induced fibrosis. In conclusion, reduced muscle HKII protein content results in impaired muscle functionality during recovery from I/R. The impaired recovery seems to be mainly a result of a greater susceptibility of HKII(+/-) mice to the initial I/R-induced necrosis (not apoptosis), and not a HKII-related deficiency in muscle regeneration.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Disease Models, Animal; Down-Regulation; Fibrosis; Glycogen; Hexokinase; Hindlimb; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microcirculation; Mitochondria, Muscle; Muscle Fatigue; Muscle Strength; Muscle, Skeletal; Necrosis; Neovascularization, Physiologic; Oxidative Stress; Recovery of Function; Regeneration; Regional Blood Flow; Reperfusion Injury; Time Factors

Hepatic ischemia/reperfusion injury (IRI) occurs during certain hepatobiliary surgeries, hemorrhagic shock, and veno-occlusive disease. Biochemical changes caused by hepatic IRI lead to hepatocellular remodeling, including cellular regeneration or irreversible apoptosis. This study aims to characterize and monitor the metabolic changes in hepatic IRI using proton magnetic resonance spectroscopy (¹H MRS).. Sprague-Dawley rats (n = 8) were scanned with ¹H MRS using 5.0 × 5.0 × 5.0 mm³ voxel over a homogeneous liver parenchyma at 7 Tesla with a respiratory-gated point-resolved spectroscopy sequence at 1 day before, 6 hours, 1 day, and 1 week after 30 minutes total hepatic IRI. Signal integral ratios of choline-containing compounds (CCC), glycogen and glucose complex (Glyu), methylene proton ((-CH₂-)(n)), and methene proton (-CH=CH-) to lipid (integral sum of methyl proton (-CH₃), (-CH₂-)(n) and -CH=CH-) were quantified by areas under peaks longitudinally.. The CCC-to-lipid and Glyu-to-lipid ratios at 6 hours after IRI were significantly higher than those at 1 day before, 1 day, and 1 week after injury. The (-CH₂-)(n)-to-lipid, and -CH=CH-to-lipid ratios showed no significant differences over different time points. Hepatocellular regeneration was observed at 6 hours after IRI in histology with immunohistochemical technique.. Changes in CCC-to-lipid and Glyu-to-lipid ratios likely reflect the hepatocellular remodeling and impaired glucose utilization upon hepatic IRI, respectively. The experimental findings in the current study demonstrated that ¹H MRS is a valuable tool for characterizing either global or regional metabolic changes in liver noninvasively and longitudinally. Such capability has the potential to lead to early diagnosis and detection of impaired liver function.

Topics: Animals; Choline; Glucose; Glycogen; Lipid Metabolism; Liver; Magnetic Resonance Spectroscopy; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury

The ability of the developing myocardium to tolerate oxidative stress during early gestation is an important issue with regard to possible detrimental consequences for the fetus. In the embryonic heart, antioxidant defences are low, whereas glycolytic flux is high. The pro- and antioxidant mechanisms and their dependency on glucose metabolism remain to be explored. Isolated hearts of 4-day-old chick embryos were exposed to normoxia (30 min), anoxia (30 min), and hyperoxic reoxygenation (60 min). The time course of ROS production in the whole heart and in the atria, ventricle, and outflow tract was established using lucigenin-enhanced chemiluminescence. Cardiac rhythm, conduction, and arrhythmias were determined. The activity of superoxide dismutase, catalase, gutathione reductase, and glutathione peroxidase as well as the content of reduced and oxidized glutathione were measured. The relative contribution of the ROS-generating systems was assessed by inhibition of mitochondrial complexes I and III (rotenone and myxothiazol), NADPH oxidases (diphenylene iodonium and apocynine), and nitric oxide synthases (N-monomethyl-L-arginine and N-iminoethyl-L-ornithine). The effects of glycolysis inhibition (iodoacetate), glucose deprivation, glycogen depletion, and lactate accumulation were also investigated. In untreated hearts, ROS production peaked at 10.8 ± 3.3, 9 ± 0.8, and 4.8 ± 0.4 min (means ± SD; n = 4) of reoxygenation in the atria, ventricle, and outflow tract, respectively, and was associated with arrhythmias. Functional recovery was complete after 30-40 min. At reoxygenation, 1) the respiratory chain and NADPH oxidases were the main sources of ROS in the atria and outflow tract, respectively; 2) glucose deprivation decreased, whereas glycogen depletion increased, oxidative stress; 3) lactate worsened oxidant stress via NADPH oxidase activation; 4) glycolysis blockade enhanced ROS production; 5) no nitrosative stress was detectable; and 6) the glutathione redox cycle appeared to be a major antioxidant system. Thus, the glycolytic pathway plays a predominant role in reoxygenation-induced oxidative stress during early cardiogenesis. The relative contribution of mitochondria and extramitochondrial systems to ROS generation varies from one region to another and throughout reoxygenation.

Topics: Animals; Chick Embryo; Electron Transport Complex I; Electron Transport Complex III; Glycogen; Glycolysis; Heart; Hypoxia; Iodoacetates; Lactates; Methacrylates; Mitochondria, Heart; Myocardium; NADPH Oxidases; NG-Nitroarginine Methyl Ester; Ornithine; Oxidative Stress; Reactive Oxygen Species; Reperfusion Injury; Rotenone; Thiazoles

The insults sustained by transplanted livers (hepatectomy, hypothermic preservation, and normothermic reperfusion) could compromise hepatic function. Hydrogen sulfide (H₂S) is a physiologic gaseous signaling molecule, like nitric oxide (NO) and carbon monoxide (CO). We examined the effect of diallyl disulfide as a H₂S donor during hypothermic preservation and reperfusion on intrahepatic resistance (IVR), lactate dehydrogenase (LDH) release, bile production, oxygen consumption, bromosulfophthalein (BSP) depuration and histology in an isolated perfused rat liver model (IPRL), after 48 h of hypothermic storage (4 °C) in University of Wisconsin solution (UW, Viaspan). Livers were retrieved from male Wistar rats. Three experimental groups were analyzed: Control group (CON): IPRL was performed after surgery; UW: IPRL was performed in livers preserved (48 h-4 °C) in UW; and UWS: IPRL was performed in livers preserved (48 h-4 °C) in UW in the presence of 3.4 mM diallyl disulfide. Hypothermic preservation injuries were manifested at reperfusion by a slight increment in IHR and LDH release compared with the control group. Also, bile production for the control group (1.32 µL/min/g of liver) seemed to be diminished after preservation by 73% in UW and 69% in UW H₂S group at the end of normothermic reperfusion. Liver samples analyzed by hematoxylin/eosin clearly showed the deleterious effect of cold storage process, partially reversed (dilated sinusoids and vacuolization attenuation) by the addition of a H₂S delivery compound to the preservation solution. Hepatic clearance (HC) of BSP was affected by cold storage of livers, but there were no noticeable differences between livers preserved with or without diallyl disulfide. Meanwhile, livers preserved in the presence of H₂S donor showed an enhanced capacity for BSP uptake (k(A) CON = 0.29 min⁻¹; k(A) UW = 0.29 min⁻¹ ; k(A) UWS = 0.36 min ⁻¹). In summary, our animal model suggests that hepatic hypothermic preservation for transplantation affects liver function and hepatic depuration of BSP, and implies that the inclusion of an H₂S donor during hypothermic preservation could improve standard methods of preparing livers for transplant.

Topics: Adenosine; Allopurinol; Allyl Compounds; Animals; Bile; Cold Ischemia; Disulfides; Gases; Glutathione; Glycogen; Hydrogen Sulfide; Insulin; L-Lactate Dehydrogenase; Liver; Liver Circulation; Liver Function Tests; Liver Transplantation; Male; Organ Preservation; Organ Preservation Solutions; Oxygen Consumption; Raffinose; Rats; Rats, Wistar; Reperfusion Injury; Sulfobromophthalein; Time Factors; Vascular Resistance

To study the effect of pre-storing glycogen on warm ischemia reperfusion injury in rat liver.. Lewis rats were divided into sham operation group (S group), low-glycogen group (L group, fasted 24 h), normal-glycogen group (N group, standard laboratory diet), high-glycogen group (H group, standard laboratory diet plus intravenous injection of 50% glucose solution 1 mL every 6 h x 4 times). Seventy percent portal ligation was performed on all of the rats for 30 min except for those in the S group. Ten rats from each group were sacrificed for harvest of serum and tissue samples 1 h, 4 h, 12 h and 24 h after reperfusion, respectively. The hepatic function was measured and the morphological changes of the livers were examined. Bcl-2, a well known antiapoptotic factor, was also detected using quantitative polymerase chain reaction.. The rats with higher glucose presented higher glycogen in hepatocytes, better hepatic function, lower levels of ALT, AST and apoptosis index (AI), and higher 1 week survival rate. These rats also showed slighter histological damage and lower apoptotic index than the rats in the other groups. Furthermore, the morphological changes of the liver tissues of the rats with higher glucose were mild. The Bcl-2 mRNA expression was the strongest.. Pre-storing glycogen might protect liver impairment caused by ischemia reperfusion injury, perhaps through enhancing the Bcl-2 expression and preventing the hepatic cells from apoptosis.

Topics: Animals; Apoptosis; Glucose; Glycogen; Liver; Male; Random Allocation; Rats; Rats, Inbred Lew; Reperfusion Injury; Warm Ischemia

An isolated perfused rat liver model was used to investigate biochemical and histologic changes during 2 hours of reperfusion after 24 hours of cold storage to compare Leeds solution (LS) with University of Wisconsin solution (UW). Compared with livers stored in UW, those perfused with LS showed significantly higher bile flow and lower enzyme production (P < .05 by 1-way analysis of variance). For example, after 120 minutes, alanine aminotransferase results were: LS 38.9 U/L vs UW 66.8 U/L and bile flows were LS 10.3 μg/15 min/g liver vs UW 9.2 μg/15 min/g liver. Histologically the reticulin breakdown was greater and its reformation slower in UW-preserved livers. Liver tissue was viable in both groups, as shown by the increased glycogen content after reperfusion in both groups, but seen at a higher rate among LS, perfused livers. In conclusion, LS compared favorably with UW to prevent ischemic damage and so could offer an alternative perfusion medium to UW.

Topics: Adenosine; Alanine Transaminase; Allopurinol; Analysis of Variance; Animals; Aspartate Aminotransferases; Bile; Cold Ischemia; Glutathione; Glycogen; In Vitro Techniques; Insulin; L-Lactate Dehydrogenase; Liver; Male; Organ Preservation; Organ Preservation Solutions; Raffinose; Rats; Rats, Wistar; Reperfusion Injury; Reticulin; Time Factors; Tissue Survival

Phosphorylated fructose compounds have been reported to lessen neuronal injury in in vitro models of hypoxia and in vivo models of ischemia. Although a variety of mechanisms have been proposed to account for this finding, it is unknown if intracellular uptake and incorporation of these compounds into the glycolytic pathway contribute to the benefit. We evaluated phosphorylated fructose administration in an adult rat model of transient, near-complete cerebral ischemia to determine its impact on brain metabolism before, during, and after ischemia. Fifty-four pentobarbital anesthetized rats were randomly assigned to receive IV infusions of either fructose-1,6-bisphosphate, fructose-2,6-bisphosphate, or 0.9% saline. After 2 hours of infusion, 18 rats (6/treatment group) were subjected to brain harvesting before any ischemia, 18 additional rats had brain harvesting at the completion of 10 minutes of forebrain ischemia (2-vessel occlusion plus induced hypotension), and 18 rats had harvesting after ischemia and 15 minutes of reperfusion. Cortical brain samples were analyzed for ATP, ADP, AMP, phosphocreatine, glucose, and glycogen. When compared with placebo, neither phosphorylated fructose compound altered preischemic, intraischemic, or postischemic concentrations of brain high-energy phosphates, glucose, glycogen, or lactate, nor did they influence the intraischemic metabolism of endogenous brain glucose or glycogen. On the basis of these results, we conclude that mechanisms other than augmented carbohydrate metabolism are responsible for previous reports of neuronal protection by the bisphosphonates.

Topics: Adenine Nucleotides; Adenosine Diphosphate; Adenosine Monophosphate; Adenosine Triphosphate; Anesthesia; Anesthetics; Animals; Blood Glucose; Brain Chemistry; Brain Ischemia; Carbohydrate Metabolism; Cerebrovascular Circulation; Electroencephalography; Fructosediphosphates; Glycogen; Hemodynamics; Lactic Acid; Phosphocreatine; Prosencephalon; Rats; Rats, Sprague-Dawley; Reperfusion Injury

To investigate if higher hepatocellular glycogen contents can alleviate hepatic ischemia reperfusion injury and its relationship to ICAM-1 gene expression in hepatic sinusoidal cells (HSCs).. Twenty-one rabbits fed with a standard diet were randomly divided into three groups (n=7 in each). All the animals were subjected to hepatic ischemia reperfusion injury then sacrificed. Before the injury, group A rabbits fasted for 24 hours; group C rabbits had 6 intravenous glucose solution (25%, 20 ml) injections, 4 hours between two injections. Hepatic enzymological changes, hepatic ICAM-1 mRNA expressions and leukocytic counts in the sinusoids were observed.. The liver glycogen contents of the three groups were significantly different. Livers of group A had higher contents of glycogen (9.85+/-0.91 mg/g. wet tissue); in group B they were 38.93+/-5.72; and in group C they were 48.31+/-6.58. Group C animals had the slightest liver function damage. There were no differences in the pre- and post-ischemic ICAM-1 mRNA contents in the three groups. However, livers with a higher content of glycogen showed less expression of ICAM-1 mRNA (group A: 1.398+/-0.365 ng/mg wet tissue; group B: 0.852+/-0.297; group C: 0.366+/-0.183) and lower leukocytic counts. The relationship analysis showed a negative relationship between hepatocellular glycogen and hepatic ICAM-1 mRNA contents (r= -0.965, P less than 0.01).. Hepatocellular glycogen is important in protecting liver ischemic reperfusion injury. Also hepatocellular glycogen decreases the expression of ICAM-1 mRNA of HSCs.

Topics: Animals; Female; Glycogen; Hepatocytes; Intercellular Adhesion Molecule-1; Liver; Male; Rabbits; Reperfusion Injury; RNA, Messenger

To investigate the effects of anoxia and glucopenia (A-G) on both male and female guinea pig urinary bladder.. In whole bladders superfused with oxygenated Krebs' solution, intrinsic nerves underwent electrical field stimulation (EFS) and smooth muscle stimulated with carbachol, ATP, and high potassium. The effect of 1, 2, or 3 hr A-G on the contractile response and the ensuing recovery in Krebs' solution, was monitored. Glycogen content in male and female urinary bladders was also measured.. Under different stimuli male urinary bladder proved to contract more efficiently than female organ. After 1 hr A-G the EFS response of male urinary bladder was virtually abolished and returned to 60% of control response in the recovery phase; in female bladder the EFS responses fully recovered during the reperfusion phase. Full recovery of the response to carbachol, ATP, and high potassium stimulations was observed in both genders. A-G had to be extended to 2 hr to cause smooth muscle impairment (higher in male than in female) and a neuronal impairment in female urinary bladders. When 2-deoxyglucose (2-DG), an inhibitor of glycolysis, was added during 1 hr A-G, both neuronal and smooth muscle damages were significantly enhanced in male, as well as, though to a lesser extent, in female bladder. A significantly higher glycogen content was observed in female as compared to male bladders, which was inversely related with the duration of exposure to A-G.. The higher resistance of female urinary bladder to A-G/reperfusion, can be partly ascribed to the higher glycogen content.

Topics: Adenosine Triphosphate; Animals; Carbachol; Cholinergic Agonists; Deoxyglucose; Female; Glucose; Glycogen; Guinea Pigs; Hypoxia; In Vitro Techniques; Male; Muscle Contraction; Muscle, Smooth; Peripheral Nervous System; Potassium Chloride; Reperfusion Injury; Sex Characteristics; Urinary Bladder

Although livers exhibit only minimal morphologic changes with age, how older livers tolerate pathologic conditions such as normothermic ischemia is unknown. Young 6-week-old mice and old 60-week-old mice underwent 60 minutes of hepatic ischemia and various periods of reperfusion. Markers of hepatocyte injury, hepatic energy content, and mitochondrial function were determined. Ischemic preconditioning and glucose injection were evaluated as protective strategies against reperfusion injury in old mice. Reperfusion injury was far worse in old mice compared with mice in the young control group. Ischemic preconditioning was highly protective against reperfusion injury in young but not in old mice. Older livers had dramatically reduced adenosine triphosphate (ATP) levels and glycogen contents. The low intrahepatic energy level in old mice was associated with a reduced mitochondrial ATP production. Preoperative injection of glucose restored the intrahepatic ATP content and protected against reperfusion injury. Furthermore, glucose injection restored the protective effect of ischemic preconditioning, resulting in additive protection when both strategies were combined. Aging of the liver is associated with mitochondrial dysfunction and decreased intrahepatic energy content, resulting in poorer tolerance against ischemic injury. Improving intrahepatic ATP levels in old livers by glucose injection protects the old liver against ischemic injury and restores the protective effects of ischemic preconditioning.

Topics: Adenosine Triphosphate; Aging; Animals; Aspartate Aminotransferases; Energy Metabolism; Glucose; Glycogen; Ischemic Preconditioning; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria; Reperfusion Injury

To investigate the effect of anoxia/glucopenia and re-superfusion on intrinsic nerves in the mammalian urinary bladder.. Strips of detrusor smooth muscle were dissected from monkey and human urinary bladder and mounted for tension recording in organ baths superfused with Krebs solution. Human, monkey, and guinea-pig urinary bladders were treated to evaluate glycogen contents by a biochemical method.. Detrusor strips from both monkeys and humans had to be exposed to anoxia-glucopenia for up to 2-2.5 hr to observe a progressive decline in the response to electrical field stimulation (EFS) of the intrinsic nerves, at variance with guinea-pig detrusor strips. In contrast, the response to direct activation of the smooth muscle with carbachol remained almost unaltered. Incubation of human and monkey detrusor strips with 2-deoxyglucose (2-DG) during 1 hr anoxia-glucopenia, however, caused a marked damage to the intrinsic nerves. The glycogen contents of both human detrusor specimens and monkey urinary bladders were 2.0- and 1.4-fold higher, respectively, than that found in guinea-pig urinary bladder; furthermore, untreated monkey detrusor sections showed a greater number of glycogen granules as compared to those subjected to anoxia-glucopenia and re-superfusion. In guinea-pig and in monkey detrusor sections glycogen granules were found in smooth muscle cells but not in neurons of intramural ganglia.. A higher susceptibility of guinea-pig as compared to monkey and human nerves has been demonstrated; it is suggested that anaerobic glucose metabolism during anoxia-glucopenia is crucial for the functional recovery of detrusor intrinsic nerves from damage caused by anoxia-glucopenia and re-superfusion.

Topics: Anaerobiosis; Animals; Antimetabolites; Carbachol; Cebus; Deoxyglucose; Electric Stimulation; Ganglia, Autonomic; Glucose; Glycogen; Glycolysis; Guinea Pigs; Humans; Hypoxia; In Vitro Techniques; Ischemia; Muscarinic Agonists; Muscle, Smooth; Oxidative Stress; Regional Blood Flow; Reperfusion Injury; Urinary Bladder

Recently, both asymmetrical dimethylarginine and IL-6 have been suggested to be associated with the induction and severity of single and multiple organ dysfunction. The aims of the present study were to elucidate if these factors were increased in an ischemia reperfusion (IR) model and whether pre-operative carbohydrate supplementation can reduce the risk factors along with the IR injury.. One group of male Wistar rats was fasted for 16 h (water ad libitum) prior to clamping the superior mesenteric artery (IR fasted n=14). A second group had ad libitum access to a carbohydrate solution prior to clamping (IR fasted CHO group n=11). Sham-fasted animals, which only received laparotomy and no clamping, served as controls (n=4).. Plasma urea and ALAT activity were both increased in the IR fasted animals when compared to the sham rats (P=0.007 and P<0.02, respectively). Furthermore, it was shown that IR fasted rats had increased ADMA and IL-6 concentration in plasma when compared to sham animals (P<0.02). Moreover, the GSH level in lung was significantly decreased in the IR fasted animals (P=0.014). IR CHO supplemented showed no significant increase of ALAT activity and decrease of lung GSH. Furthermore, significantly lower plasma urea, ADMA and IL-6 concentration was seen in the IR CHO supplemented group when compared to the IR fasted rats (P=0.028, P<0.01 and P<0.02, respectively). The liver glycogen concentration in IR fasted rats was 48% of that IR rats supplemented the carbohydrate mixture.. The present rat intestinal ischemia reperfusion model not only induces organ injury indicated by the classical parameters such as plasma urea and ALAT activity, but also increased plasma IL-6 and ADMA and decreased lung GSH concentration in IR fasted rats. Pre-operative supplementation with the carbohydrate mixture significantly lowered the plasma urea, IL-6 and ADMA concentrations and maintained lung GSH concentration. This indicates that pre-operative carbohydrate supplementation reduces post-operative organ injury.

Topics: Alanine Transaminase; Animals; Arginine; Blood Urea Nitrogen; Dietary Carbohydrates; Dietary Supplements; Disease Models, Animal; Glutathione; Glycogen; Interleukin-6; Liver; Male; Multiple Organ Failure; Preoperative Care; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Risk Factors

To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury.. The rats were randomized into five groups, WIT was 0, 15, 30, 45, 60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation.. The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min.. Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.

Topics: Adenosine Triphosphatases; Animals; Electron Transport Complex IV; Glycogen; Hot Temperature; Liver; Liver Transplantation; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Succinate Dehydrogenase

Microcirculation disturbances are essential factors of preservation injury in fatty liver. However, hepatocyte injury is also markedly excessive in fatty liver resulting, at least in part, from energy metabolism impairment and oxidative stress. Thus, this study aimed to determine whether nutritional status influences preservation injury in fatty liver and whether energetic substrate supplementation, alone or with a vasodilator, is protective.. Normal or fatty livers induced by a choline-deficient diet were isolated from fed and fasted rats, preserved in University of Wisconsin solution at 4 degrees C for 18 h, and then reperfused with Krebs-Henseleit solution at 37 degrees C for 120 min. Fasted rats with fatty liver were also treated as follows: (1) Glucose supplementation: rats had access to a glucose solution for 18 h prior procurement; (2) Prostaglandin (PG): alprostadil was continuously infused during reperfusion; (3) Combined treatment: Glucose supplementation + PG.. Fasting-induced liver injury was significantly greater in fatty than normal liver. In fatty livers from fasted rats, all treatments reduced the alanine aminotransaminase release. Hepatic oxygen consumption improved in the glucose and glucose + PG groups, while PG infusion had no effect. Glucose supplementation did not affect portal pressure, which, in contrast, was reduced in livers receiving PG. Finally, all treatments lowered oxidative injury.. Preservation injury in fatty liver is greatly related to nutritional status. Energetic substrate supplementation may represent a clinically feasible protective strategy and a multistep approach adding vasodilators could offer further benefit by acting on different pathogenetic mechanisms.

Topics: Alanine Transaminase; Animal Nutritional Physiological Phenomena; Animals; Dietary Supplements; Fasting; Fatty Liver; Glucose; Glycogen; In Vitro Techniques; Liver; Male; Organ Preservation; Prostaglandins; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Normothermic ischemia-reperfusion is a determinant in liver injury occurring during surgical procedures, ischemic state, and multiple organ failure. The preexisting nutritional status of the liver might contribute to the extent of tissue injury and primary nonfunction. The aim of this study was to determine the role of starvation on hepatic ischemia-reperfusion injury in normal rat livers.. Rats were randomly divided into two groups: one had free access to food, the other was fasted for 16 h. The portal vein was cannulated, and the liver was removed and perfused in a closed ex vivo system. Two modes of perfusion were applied in each series of rats, fed and fasting. In the ischemia-reperfusion mode, the experiment consisted of perfusion for 15 min, warm ischemia for 60 min, and reperfusion during 60 min. In the nonischemia mode, perfusion was maintained during the 135-min study period. Five rats were included in each experimental condition, yielding a total of 20 rats. Liver enzymes, potassium, glucose, lactate, free radicals, i.e., dienes and trienes, and cytochrome c were analyzed in perfusate samples. The proportion of glycogen in hepatocytes was determined in tissue biopsies.. Transaminases, lactate dehydrogenase, potassium, and free radical concentrations were systematically higher in fasting rats in both conditions, with and without ischemia. Cytochrome c was higher after reperfusion in the fasting rats. Glucose and lactate concentrations were greater in the fed group. The glycogen content decreased in both groups during the experiment but was markedly lower in the fasting rats.. In fed rats, liver injury was moderate, whereas hepatocytes integrity was notably impaired both after continuous perfusion and warm ischemia in fasting animals. Reduced glycogen store in hepatocytes may explain reduced tolerance.

Topics: Animals; Bilirubin; Biomarkers; Blood Glucose; Cytochromes c; Enzyme-Linked Immunosorbent Assay; Enzymes; Female; Glycogen; Hepatectomy; In Vitro Techniques; Lactic Acid; Liver; Liver Function Tests; Liver Glycogen; Nutritional Status; Oxidative Stress; Perfusion; Potassium; Rats; Rats, Wistar; Reperfusion Injury

The great resistance of muscle to ischemia was used to study blood flow-dependent phenomena produced by anesthetic drugs in this condition. A short reperfusion period was used in order to favor metabolic changes indicative of an effect of chlorpromazine (CPZ) on blood flow. Gracilis muscles of dogs were submitted to 5 h of ischemia and 30 min of reperfusion. CPZ-treated animals were injected I.V. (2 mg/kg) 10 min before the beginning of ischemia. Biopsies provided the material for tissue measurements. Lactate content and pH were determined in blood samples collected from a muscle efferent vein. In both the CPZ-treated and nontreated groups, ischemia induced a decline in muscle glycogen content, with a corresponding increase in muscle lactate and a decrease in mitochondrial respiratory control ratio. After 30 min of reperfusion, tissue levels of lactate did not attain preischemic values but showed a clear decline in the two experimental groups, evidencing the reversible state of the muscle. All other metabolic parameters remained unchanged. Mitochondrial respiratory control remained functional during ischemia and reperfusion. Blood pH displayed similar changes in both groups. There was no metabolic indication that the drug affected blood flow during early reperfusion and/or of a greater sensitivity of muscle endothelial cells to anesthetic drugs.

Topics: Animals; Chlorpromazine; Disease Models, Animal; Dogs; Glycogen; Hydrogen-Ion Concentration; Ischemia; Lactates; Mitochondria, Muscle; Muscle Contraction; Muscle, Skeletal; Musculoskeletal Physiological Phenomena; Reference Values; Reperfusion Injury

H11 kinase is a serine/threonine kinase preferentially expressed in the heart, which participates in cardiac cell growth and also in cytoprotection during ischemia. A cardiac-specific transgenic mouse overexpressing H11 kinase (2- to 7-fold protein increase) has been generated, and is characterized by cardiac hypertrophy with preserved function and protection against irreversible damage during ischemia/reperfusion. In this study, we tested whether H11 kinase also participates in the metabolic adaptation to cardiac hypertrophy and ischemia.. A yeast two-hybrid screen using H11 kinase as a bait in a human heart library revealed a potential interaction with phosphoglucomutase (PGM), the enzyme converting glucose 6-phosphate into glucose 1-phosphate. Interaction between H11 kinase and PGM was confirmed by co-immunoprecipitation. To test the biochemical relevance of this interaction, PGM activity was measured in the heart from wild type and transgenic mice, showing a 20% increase of Vmax in the transgenic group, without change in KM. Glycogen content was increased proportionately to the expression of the transgene, reaching a 40% increase in high-expression transgenic mice (7-fold increase in H11 kinase protein) versus wild type (p < 0.01). Increased incorporation of glucose into glycogen was coupled to a 3-fold increase in the protein expression of the glucose transporter GLUT1 in plasma membrane of transgenic mice (p < 0.01).. H11 kinase promotes the synthesis of glycogen, an essential fuel for the stressed heart in both conditions of overload and ischemia. Therefore, H11 kinase represents an integrative sensor in the cardiac adaptation to stress by coordinating cell growth, survival and metabolism.

Topics: Animals; Blotting, Western; Cell Membrane; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Glucose Transporter Type 1; Glycogen; Heat-Shock Proteins; Humans; Immunoprecipitation; Kinetics; Mice; Mice, Transgenic; Molecular Chaperones; Monosaccharide Transport Proteins; Myocardial Ischemia; Myocardium; Phosphoglucomutase; Protein Serine-Threonine Kinases; Protein Structure, Tertiary; Proteins; Reperfusion Injury; Transgenes; Two-Hybrid System Techniques

To evaluate the effect of glycogen on calcium concentration of rabbit donor liver during ischemia-reperfusion period.. Donor group (n=21) was divided into 3 subgroups randomly: Group A (n=7): fasting for 24 hours before harvesting; Group B (n=7): normal laboratory chew; Group C (n=7): normal laboratory chew plus glucose supplement intravenously. Based on the self-created animal model for ischemia-reperfusion, the levels of glycogen content, ATP level, viability of Ca(2+)ATPase and plasmic free Ca(2+) concentration ([Ca(2+)]i) of liver tissue were measured.. Before cold preservation, there was a significant difference of glycogen content among the three groups at all time points except at the end of rewarming period. ATP level and Ca(2+)ATPase viability were significantly higher in group C than in other two groups. But the plasmic free Ca(2+) concentration was lower in groups with higher glycogen content.. Donor liver with high glycogen content can provide relatively sufficient ATP, maintain better Ca(2+)ATPase viability and prevent plasmic free Ca(2+) concentration overloading. This maybe an important mechanism for glycogen to ameliorate ischemia-reperfusion injury to the donor livers.

Topics: Adenosine Triphosphate; Animals; Calcium; Calcium-Transporting ATPases; Cytosol; Female; Glycogen; Liver Diseases; Liver Transplantation; Male; Models, Animal; Rabbits; Reperfusion Injury

The effects of estrogen and ovariectomy on indexes of muscle damage after 2 h of complete hindlimb ischemia and 2 h of reperfusion were investigated in female Sprague-Dawley rats. The rats were assigned to one of three experimental groups: ovariectomized with a 17beta-estradiol pellet implant (OE), ovariectomized with a placebo pellet implant (OP), or control with intact ovaries (R). It was hypothesized that following ischemia-reperfusion (I/R), muscle damage indexes [serum creatine kinase (CK) activity, calpain-like activity, inflammatory cell infiltration, and markers of lipid peroxidation (thiobarbituric-reactive substances)] would be lower in the OE and R rats compared with the OP rats due to the protective effects of estrogen. Serum CK activity following I/R was greater (P < 0.01) in the R rats vs. OP rats and similar in the OP and OE rats. Calpain-like activity was greatest in the R rats (P < 0.01) and similar in the OP and OE rats. Neutrophil infiltration was assessed using the myeloperoxidase (MPO) assay and immunohistochemical staining for CD43-positive (CD43+) cells. MPO activity was lower (P < 0.05) in the OE rats compared with any other group and similar in the OP and R rats. The number of CD43+ cells was greater (P < 0.01) in the OP rats compared with the OE and R rats and similar in the OE and R rats. The OE rats had lower (P < 0.05) thiobarbituric-reactive substance content following I/R compared with the R and OP rats. Indexes of muscle damage were consistently attenuated in the OE rats but not in the R rats. A 10-fold difference in serum estrogen content may mediate this. Surprisingly, serum CK activity and muscle calpain-like activity were lower (P < 0.05) in the OP rats compared with the R rats. Increases in serum insulin-like growth factor-1 content (P < 0.05) due to ovariectomy were hypothesized to account for this finding. Thus both ovariectomy and estrogen supplementation have differential effects on indexes of I/R muscle damage.

Topics: Animals; Antigens, CD; Calpain; Creatine Kinase; Estrogens; Female; Glycogen; Hindlimb; Insulin-Like Growth Factor I; Lactic Acid; Leukosialin; Lipid Peroxidation; Muscle, Skeletal; Neutrophil Infiltration; Ovariectomy; Peroxidase; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sialoglycoproteins; Thiobarbituric Acid Reactive Substances

Mice were randomly divided into groups H4 (hypoxic preconditioning group with repetitive hypoxic exposures for four runs), H(1) (hypoxic control group with exposure to hypoxia for one run) and H(0) (normal control group with no exposure to hypoxia). Glycogen content of whole brain of group H4 was found to be significantly higher than that of groups H(1) and H(0). The glycogen content in telencephalon, diencephalon and pons of group H4 was markedly higher than that in the corresponding areas of groups H(1) and H(0). Glycogen content of whole brain in group H(1) was markedly lower than that in group H(0), whereas no significant difference was seen in these brain subregions between groups H(1) and H(0). Brain lactate contents of groups H4 and H(1) did not show significant difference, though they were significantly higher than that of group H(0). Blood lactate content of group H4 was significantly lower than those of groups H(1) and H(0). The results above indicate that the concomitant increase of glycogen and decrease of lactate in the brain are due to the participation of aerobic metabolism during hypoxic preconditioning or the formation of tolerance to hypoxia.

Topics: Animals; Brain; Diencephalon; Female; Glycogen; Hypoxia, Brain; Ischemic Preconditioning; Lactic Acid; Male; Mice; Mice, Inbred BALB C; Pons; Random Allocation; Reperfusion Injury; Telencephalon

Insulin has been reported to be neuroprotective during cerebral ischemia/reperfusion. However, it may also increase the sensitivity of cultured cortical neurons to glutamate toxicity. The experiments described here utilized a rat four-vessel occlusion model with cerebral cortical windows to determine the effects of intravenous insulin, alone (I) or combined with glucose (IG) to maintain physiologic blood glucose levels, on the extracellular accumulation of amino acids in superfusates of the cerebral cortex. Aspartate, phosphoethanolamine, taurine and gamma-aminobutyric acid were increased in the I and IG groups and glutamate was increased in the IG group compared to controls during ischemia/reperfusion. Insulin treatment attenuated the rebound in cortical superfusate glucose levels in both groups of animals during reperfusion. The increases in amino acid release during reperfusion may be due to a lack of glycolytically derived energy available for amino acid uptake systems and ionic pumps.

Topics: Animals; Aspartic Acid; Brain Chemistry; Cerebral Cortex; Energy Metabolism; gamma-Aminobutyric Acid; Glucose; Glutamic Acid; Glycogen; Hypoglycemia; Hypoglycemic Agents; Injections, Intravenous; Insulin; Ischemic Attack, Transient; Lactic Acid; Male; Neurotoxins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Taurine

In order to examine glucose metabolism in liver grafts after cold ischemia and reperfusion, the heterogeneous lobular distribution pattern of glycogen content was studied using histochemical quantitative analysis. In most of the cases, this heterogeneous pattern of glycogen was observed after preservation and reperfusion. However, a 42% reduction of glycogen content, expressed as the ratio between stained surface and total surface of liver biopsies, was observed in biopsies after reperfusion. Moreover, both periportal and centrilobular hepatocytes showed a significant decrease in mean optical density after reperfusion (18% and 25%, respectively). The comparison of our results to early postoperative liver function tests and cold ischemia times showed no significant correlation (p<0.05).

Topics: Adolescent; Adult; Cells, Cultured; Child; Glycogen; Hepatocytes; Histocytochemistry; Humans; Liver Function Tests; Liver Transplantation; Middle Aged; Reperfusion Injury; Transplantation, Homologous

Fatty livers are more sensitive to the deleterious effects of ischemia-reperfusion than normal livers. Nutritional status greatly modulates this injury in normal livers, but its role in the specific setting of fatty liver is unknown. This study aimed to determine the effect of nutritional status on warm ischemia-reperfusion injury in rat fatty livers. Fed and fasted rats with normal or fatty liver induced by a choline deficient diet underwent 1 hour of lobar ischemia and reperfusion. Rat survival was determined for 7 days. Serum transaminases, liver histology and cell ultrastructure were assessed before and after ischemia, and at 30 minutes, 2 hours, 8 hours, and 24 hours after reperfusion. Survival was also determined in fatty fasted rats supplemented with glucose before surgery. The preischemic hepatic glycogen was measured in all groups. Whereas survival was similar in fasted and fed rats with normal liver (90% vs. 100%), fasting dramatically reduced survival in rats with fatty liver (14% vs. 64%, P <.01). Accordingly, fasting and fatty degeneration had a synergistic effect in exacerbating liver injury. Mitochondrial damage was a predominant feature of ultrastructural hepatocyte injury in fasted fatty livers. Glucose supplementation partially prevented the fasting-induced depletion of glycogen and improved the 7-day rat survival to 45%. These data indicate that rat fatty livers exposed to normothermic ischemia-reperfusion injury are much more sensitive to fasting than histologically normal livers. Because glucose supplementation improves both the hepatic glycogen stores and the rat survival, a nutritional repletion procedure may be part of a treatment strategy aimed to prevent ischemia-reperfusion injury in fatty livers.

Topics: Alanine Transaminase; Animals; Choline Deficiency; Fatty Liver; Food Deprivation; Glucose; Glycogen; Liver; Male; Microscopy, Electron; Nutritional Status; Rats; Rats, Wistar; Reperfusion Injury; Survival Rate

In order to examine glucose metabolism in liver grafts after cold ischemia and reperfusion, the heterogeneous lobular distribution pattern of glycogen content and glucose-6-phosphatase activity was studied using histochemical methods. The characteristic heterogeneous lobular distribution pattern of glycogen and glucose-6-phosphatase was maintained after preservation and reperfusion. However, it appeared that glycogen content decreased in both periportal and centrilobular hepatocytes after reperfusion. The glycogen decrease was higher in periportal hepatocytes. Glucose-6-phosphatase activity was maintained after reperfusion in most of the cases in periportal hepatocytes. In centrilobular hepatocytes, more cases showed a decrease in enzyme activity. It is suggested that ischemia-reperfusion mainly affects the glycogen content in both periportal and centrilobular hepatocytes and that centrilobular glucose-6-phosphatase activity is more sensitive to ischemia-reperfusion injury than periportal hepatocytes.

Topics: Adolescent; Adult; Biopsy; Child; Cryopreservation; Glucose-6-Phosphatase; Glycogen; Humans; Ischemia; Liver; Liver Transplantation; Middle Aged; Reperfusion Injury; Transplantation, Homologous

Although discontinuous total parenteral nutrition (d-TPN) has recently been favored for clinical use over continuous total parenteral nutrition (c-TPN) to ameliorate liver dysfunction, mechanisms for the protection against postoperative liver dysfunction remain unknown. This study aimed to examine differences in mitochondrial function in d-TPN- and c-TPN-pretreated livers during ischemia-reperfusion. Rat livers pretreated with d-TPN or c-TPN were perfused with Krebs-Ringer buffer and were exposed to 25% low-flow hypoxia followed by reperfusion. Intrahepatic mitochondrial membrane potential (triangle up) and cell viability were assessed by dual-color digital microfluorography using rhodamine 123 (Rh123) and propidium iodide (PI), respectively. In response to hypoxia, livers pretreated with c-TPN, d-TPN, and an ordinary chow diet exhibited a significant triangle up reduction among the entire lobules. Upon reperfusion, the regional triangle up values further decreased in the c-TPN liver, whereas those in the d-TPN-treated or chow-treated livers displayed a rapid recovery toward the control levels. The severity of cell injury did not differ among the groups, showing that the reperfusion-induced triangle up drop in the c-TPN-pretreated liver is not a consequence of cell injury. Differences in the triangle up drop among the groups appear to occur irrespective of those in the glycogen storage, because the livers undergoing d-TPN display a marked triangle up recovery even when reperfused at the end of a fasted state. These results indicate that c-TPN, but not d-TPN, jeopardizes mitochondrial re-energization and suggest that a circadian pattern of the TPN serves as a potentially beneficial strategy to reduce the risk of postischemic mitochondrial dysfunction in the liver.

Topics: Animals; Bile; Cell Survival; Fluorescent Dyes; Glycogen; Intracellular Membranes; Ischemia; Liver; Liver Diseases; Male; Membrane Potentials; Mitochondria, Liver; Nutritional Status; Parenteral Nutrition, Total; Phagocytosis; Rats; Rats, Wistar; Reperfusion Injury; Rhodamine 123

We investigated, at first in low-flow global ischemia and then with ischemic preconditioning, the effects of a compound, (4-isopropyl-3-methylsulphonylbenzoyl)guanidine hydrochloride (HOE 642), known to inhibit the Na+/H+ exchange in rat cardiomyocytes. In rat isolated hearts, perfused on a Langendorff apparatus with Krebs-Henseleit carbonate buffer, the action potentials and the contractile function were measured during a 25-min period of global low-flow ischemia (coronary flow, 0.3 mL.min-1) followed by a 30-min reperfusion. In hearts previously preconditioned, two intermittent periods of total ischemia for 5 min each, separated by 5 min reflow, were performed before low-flow ischemia. Treated hearts received HOE 642 (3.0 x 10(-8) mol.min-1) exclusively during low-flow ischemia. Treatment with HOE 642 during low-flow ischemia improves cardiac performance and lowers the rise in diastolic tension during reperfusion. Concomitantly HOE 642 shortens the action potential, and has striking effects on ventricular arrhythmias during reperfusion as well. These results support the concept that Na+/H+ exchange activation is a contributing factor to low-flow ischemia-reperfusion injuries. HOE 642 exhibited minor effects when combined with the preconditioning protocol, but a lengthening in action potential was observed and ventricular arrhythmias were mostly affected. Preconditioned hearts demonstrated marked glycogen depletion compared with controls. These results support the hypothesis that preconditioning could decrease glycogenolysis and therefore subsequently limit acidification during low-flow ischemia.

Topics: Action Potentials; Animals; Electrophysiology; Female; Glycogen; Guanidines; Heart; Hemodynamics; Myocardial Contraction; Myocardial Ischemia; Myocardium; Rats; Rats, Wistar; Reperfusion Injury; Sodium-Hydrogen Exchangers; Sulfones

Recent studies have demonstrated that skeletal muscle cells are resistant to prolonged periods of ischaemia, but damage is observed after reperfusion. Periods of time longer than three hours of normothermal ischaemia in skeletal muscle lead to irreversible lesions. In the present study muscle metabolism during ischaemia and reperfusion was studied. After three hours of ischaemia two experimental groups were produced depending on whether or not they were to be followed by two hours of reperfusion. Adult mongrel dogs were submitted to ischaemia of the gracilis muscle. In this tissue, energetic metabolism was evaluated by its mitochondrial function and by glycogen level measurement. In a second experimental group the same ischaemic period was followed by two hours of reperfusion. The contralateral muscle of the same animal was used as a control. No changes in mitochondrial function, analysed by respiratory control ratio (RCR) or in any of its components, basal (state IV respiration) or ADP-activated (state III respiration) was observed. Glycogen levels also remained unaffected during the three hour ischaemic period and after two hours of reperfusion. We conclude that in the present dog model of gracilis preparation the skeletal muscle displays great resistance to ischaemia and reperfusion.

Topics: Animals; Dogs; Energy Metabolism; Glycogen; Hindlimb; Mitochondria, Muscle; Muscle, Skeletal; Oxygen Consumption; Reperfusion Injury; Time Factors

The primary objective of this study was to attempt to induce excessive intraglial acidosis during ischemia by subjecting rats to an initial insult which leads to post insult accumulation of glycogen, presumed to accumulate primarily in astrocytes. The initial insults were 15 min of transient forebrain ischemia, 30 min of hypoglycemic coma, and intraperitonial injection of methionine-sulphoximine (MSO). In the first two of these insults, glycogen content in neocortex increased to 6-7 mM kg(-1) after 6 h of recovery, and in MSO-treated animals even higher values were measured 24 h after administration ( 12 mM kg(-1)). In spite of this glycogen loading, the amount of lactate formed during a subsequent ischemic insult (of 5-30 min duration) did not exceed values usually obtained during complete ischemia in animals with normal glycogen contents (tissue lactate contents of 15 mM kg(-1)) This was because appreciable amounts of glycogen (3-7 mM kg(-1)) remained undegraded even after 30 min of ischemia. The undigested part largely reflected the extra amount of glycogen accumulated after the initial insults. It is discussed whether this part is unavailable to degradation by phosphorylase.

Topics: Acidosis; Animals; Astrocytes; Brain; Brain Ischemia; Coma; Energy Metabolism; Glycogen; Hypoglycemia; Ischemic Attack, Transient; Male; Methionine Sulfoximine; Phosphorylation; Rats; Rats, Wistar; Reperfusion Injury; Seizures

The dietary polyunsaturated fatty acids are well known to promote the cardiac output and to protect the myocardium against arrhythmias. The exogenous glucose is generally considered as a protective agent against arrhythmias resulting from ischemia and reperfusion. But the effects of dietary fats, which also influence arrhythmias, on this beneficial effect of glucose has not been yet considered. We have studied the effects of a 7 days diet with or without polyunsaturated fatty acids on the cardiac performance and arrhythmias of isolated rat hearts, perfused with saline containing either glucose 5.5 mM or 11 mM. Acute regional ischemia was produced by ligature of the left main coronary artery with subsequent release to achieve reperfusion for some hearts. Previously, our results showed that the dietary polyunsaturated fatty acids led to an enhancement of the cardiac performance and to a decreased susceptibility to arrhythmias. The present data showed that the protective action of the exogenous glucose appeared to be dependent of the dietary lipid profile. Dietary polyunsaturated fatty acids increase cardiac performance under ischemia and decrease ventricular arrhythmias' occurrence under ischemia and on reperfusion. It might be related to endogenous substrate utilization and exogenous glucose availability which was influenced by the coronary flow.

Topics: Animals; Arrhythmias, Cardiac; Cardiac Output; Coronary Circulation; Coronary Disease; Dietary Fats, Unsaturated; Glucose; Glycogen; Heart Rate; Male; Myocardium; Oxygen Consumption; Phospholipids; Rats; Rats, Inbred Strains; Reperfusion Injury; Triglycerides

We studied the effect of iv administration of biodegradable macromolecules on microvascular permeability after ischemia-reperfusion injury in a rat gastrocnemius model. After 2 h of tourniquet ischemia of the rats' hind limb, groups of animals were given iv lactated Ringer's solution (RL), serum albumin 5%, or varying MW fractions of biodegradable macromolecules of hydroxyethyl starch (HES), glycogen, and dextran. At the conclusion of the 24-h reperfusion period, the rat gastrocnemius muscles were collected. Water and K+ differences between the ischemic and control muscles were compared. Rats given a 100,000 to 300,000-dalton fraction of HES had significantly decreased water content (5.1 +/- 3.4%) when compared to rats receiving RL (8.3 +/- 2.2, p less than .01), less than 100,000 dalton HES (8.3 +/- 3.2, p less than .05), less than 300,000 glycogen (7.9 +/- 2.5, p less than .01), or dextran 150,000 (8.3 +/- 1.5, p less than .05). Rats given 100,000 to 300,000-dalton HES also had significantly higher ischemic muscle K+ content as compared to the nontourniquet control (difference 14.2 +/- 9.7 mEq/g) than rats receiving any of the other solutions (range 32.5 to 39.3) except the 300,000 to 1,000,000-dalton fraction of HES. Regression analysis comparison of K+ difference to the histologic evaluation of the muscles on the criteria of polymorphonuclear infiltration and interstitial edema (0, best; 3, worst) had a Pearson correlation coefficient of r = .73. Reduction of abnormally increased microvascular permeability may be accomplished by the iv use of appropriate sized biodegradable macromolecules.

Topics: Animals; Body Water; Capillary Permeability; Dextrans; Glycogen; Hydroxyethyl Starch Derivatives; Isotonic Solutions; Leg; Male; Potassium; Rats; Rats, Inbred Strains; Reperfusion Injury; Ringer's Lactate; Serum Albumin; Starch