Metabolic aspects of reperfusion syndrome in patients with chronic ischemia of the lower limbs after surgical revascularization

24 patients with chronic lower limb ischemia were examined during arterial reconstructive surgery and on the first postoperative day. The parameters of acid-base balance, lipid peroxidation and antioxidant system were measured in arterial and venous blood to determine laboratory criteria of the reperfusion syndrome. The arteriovenous oxygen difference decreased after revascularization while chemiluminescence emission, malonic dialdehyde concentration, antioxidant activity coefficient and medium-weight molecules elevated. On the first postoperative day all these parameters recovered but remained higher than their baseline values. These data illustrate excessive production of free oxygen radicals after limb revascularization, which contributes to reperfusion syndrome. Since determination of lipid peroxidation and antioxidant activity is a time-consuming work, levels of medium-weight molecules content in plasma may indicate reperfusion damage to the limb.     

Effect of nitroglycerine on some parameters of the prooxidant-antioxidant balance and functional state of the liver during ischemia/reperfusion

The effect of nitroglycerine on some parameters of the prooxidant-antioxidant balance and functional state of the liver under conditions of ischemia/reperfusion was studied on rabbits. Hepatic ischemia/reperfusion was accompanied by accumulation of LPO products, depletion of the antioxidant defense system, and increase in blood transaminase activity. Nitroglycerine infusion before the reperfusion period decreased the concentration of LPO products, increased activity of the antioxidant system, and improved liver function. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 12, pp. 631–634, December, 2006     

Affinity of hemoglobin for oxygen and prooxidant-antioxidant equilibrium after administration of lipopolysaccharide during correction of the L-arginine—NO pathway

Effects of correction of the L-arginine—NO pathway on the fever reaction, oxygen transport function of the blood, and prooxidant-antioxidant equilibrium in rats injected intramuscularly with lipopolysaccharide were studied. pH, Pco₂, Po₂, and the index of hemoglobin oxygen affinity (p50) were measured in mixed venous blood. Levels of Schiff bases, α-tocopherol, and catalase activity were determined in erythrocytes and in the liver, kidneys, and heart. NO synthase inhibitor attenuated the fever reaction and decreased p50 to 28.89±0.83 mm Hg (in rats administered with lipopolysaccharide, p50 was 34.21±1.63 mm Hg). The increase in the content of Schiff bases and the exhaustion of the antioxidant system in erythrocytes and tissues were less pronounced in rats injected with the NO synthase inhibitor than in animals receiving lipopolysaccharide only. Various parameters of the prooxidant-antioxidant equilibrium correlated with p50. Thus, hemoglobin oxygen affinity and NO are important factors involved in the maintenance of the prooxidant-antioxidant equilibrium in the body. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 616–619, June, 1999     

Application of an isolated heart model to investigate blood-oxygen delivery.

To avoid the compensatory hemodynamic responses, which have limited interpretation of hemoglobin-oxygen affinity modifications in animal experimentation, an isolated blood-perfused rabbit heart model providing metabolic, functional, and vectorcardiographic measurements has been developed. Fixed-flow perfusions of unchanged or affinity-modified red blood cell suspensions were carried out to assess the benefits of high affinity during hypoxic hypoxia and of low affinity during posthypoxic recovery. Using fully saturated suspensions, the influence of affinity level during restricted flow and reperfusion was also studied. Higher myocardial oxygen consumption (MVO2) was associated with high-affinity blood during mild hypoxia and low-affinity blood during posthypoxic recovery. At low flows, heart rate and MVO2 tended to be lower in high-affinity perfusions, and to recover more completely during low-affinity reperfusions. Ventricular function, vectorcardiographic patterns, and lactate levels were affected by hypoxia and ischemia, but not by level of affinity. The relevance of these observations to the therapeutic potential of hemoglobin-oxygen affinity modification is discussed.     

Effect of Transplantation of Human Fetal Tissues on Prooxidant-Antioxidant Equilibrium in the Liver and Blood Rats after Partial Hepatectomy in Rats

We studied the effect of transplantation of fetal liver cells and postnuclear cytoplasmic fraction from human fetal soft tissues on the prooxidant-antioxidant equilibrium in the liver and blood of rats after partial hepatectomy. The preparations increased antioxidant activity and decreased the intensity of lipid peroxidation, which probably contributes to their therapeutic effects.     

Protective effects of Picorrhiza kurroa extract against 2-acetylaminofluorene-induced hepatotoxicity in Wistar rats.

Picrorrhiza kurroa has been shown to impart significant hepatoprotective activities, partly by modulation of free radical--induced lipid peroxidation. Lipid peroxidation and reactive oxygen species are associated with hepatic injury. The effect of P. kurroa treatment on the antiproliferative response and, hepatic antioxidant enzymes of rats administered with 2-acetylaminofluorene (2-AAF) was studied in Wistar rats. 2-AAF (50 mg/kg body weight, i.p.) enhances hepatic lipid peroxidation, with reduction in hepatic glutathione content, glutathione peroxidase, glutathione reductase, catalase, and glutathione-s-transferase. There was an increase in the levels of transaminase enzymes and LDH. 2-AAF treatment also enhanced ornithine decarboxylase (ODC) activity and [3H] thymidine incorporation into hepatic DNA. Pretreatment of rats orally with P. kurroa extract (250 and 500 mg/kg body weight) resulted in significant decrease in lipid peroxidation, transaminase enzymes, LDH, hepatic ODC activity, and DNA synthesis (p < 0.001). Hepatic glutathione content (p < 0.001), glutathione metabolizing enzymes (p < 0.001), and antioxidant enzymes were also recovered to significant level (p < 0.001).     

The role of epidermal growth factor in prevention of oxidative injury and apoptosis induced by intestinal ischemia/reperfusion in rats

Intestinal ischemia/reperfusion is a major problem which may lead to multiorgan failure and death. The aim of the study was to evaluate the effects of epidermal growth factor (EGF) on apoptosis, cell proliferation, oxidative stress and the antioxidant system in intestinal injury induced by ischemia/reperfusion in rats and to determine if EGF can ameliorate these toxic effects. Intestinal ischemia/reperfusion injury was produced by causing complete occlusion of the superior mesenteric artery for 60 min followed by a 60-min reperfusion period. Animals received intraperitoneal injections of 150 μg/kg human recombinant EGF 30 min prior to the mesenteric ischemia/reperfusion. Mesenteric ischemia/reperfusion caused degeneration of the intestinal mucosa, inhibition of cell proliferation, stimulation of apoptosis and oxidative stress in the small intestine of rats. In the ischemia/reperfusion group, lipid peroxidation was stimulated accompanied by increased intestinal catalase and glutathione peroxidase activities, however, glutathione levels and superoxide dismutase activities were markedly decreased. EGF treatment to rats with ischemia/reperfusion prevented the ischemia/reperfusion-induced oxidative injury by reducing apoptosis and lipid peroxidation, and by increasing antioxidant enzyme activities. These results demonstrate that EGF has beneficial antiapoptotic and antioxidant effects on intestinal injury induced by ischemia/reperfusion in rats.     

大鼠全脑缺血再灌后,丙二醛及超氧化物歧化酶活性的变化

大鼠全脑缺血30分钟再灌5分钟,脑组织丙二醛(MDA)含量显著高于对照组,再灌15分钟达高峰;同时脑组织超氧化物歧化酶(SOD)的活性在全脑缺血期下降,提示脂质过氧化主要发生于全脑缺血再灌注早期。     

Age-related alterations in antioxidant capacity and lipid peroxidation in brain, liver, and lung homogenates of normal and vitamin E-deficient rats.

Age-related alterations in both antioxidant capacity and lipid peroxidation in the cerebrum, lung and liver homogenates of normal and vitamin E-deficient rats were investigated. The antioxidant capacity, which includes superoxide dismutase, catalase and glutathione peroxidase activities and vitamin E (alpha-tocopherol) concentration, was relatively stable throughout the lifespan. It was observed, however, that catalase and glutathione peroxidase activities in livers of old rats decreased and that vitamin E concentration in lung and liver increased with age. In vitamin E-deficient animals, catalase activity in liver increased and glutathione peroxidase activity in liver and lung decreased. Lipid peroxidation was monitored by use of three different indices, i.e. the thiobarbituric acid (TBA) value, oxygen absorption and conjugated-diene formation. In the absence of any initiator, neither oxygen absorption into tissue homogenates nor conjugated-diene formation in lipid extracts from the homogenates occurred. The TBA value of each cerebrum homogenate incubated under air or an oxygen atmosphere was larger than that of the corresponding unincubated cerebrum homogenate. From comparison between the TBA value and oxygen absorption, this increase in the TBA value was suggested to be due to some reactions other than lipid peroxidation. Although tissue homogenates examined contained TBA-reacting materials, no lipid peroxidation seems to arise during incubation of them. No age-related alterations in the TBA value and oxygen absorption in rat tissue homogenates were observed. Vitamin E deficiency had no effect on the TBA values of cerebrum and lung homogenates, while it seemed to increase the TBA values of liver homogenates. Vitamin E deficiency had no effect on oxygen absorption in these tissue homogenates. The induction period of initiator-induced conjugated-diene formation in lipid extracts from liver and lung homogenates from normal and vitamin E-deficient rats tended to be extended with age. Vitamin E deficiency decreased the induction period of initiator-induced conjugated-diene formation. As a result, the length of the induction period was found to be proportional to vitamin E concentration in lipid extracts. The overall antioxidant capacity of rat tissues appears to be maintained without large variation during ageing. Decreases in the capacity of some antioxidant factors may be compensated by increases in the capacity of other factors.     

Protective effects of <Emphasis Type="Italic">N</Emphasis>-acetylcysteine and <Emphasis Type="Italic">Ginkgo biloba</Emphasis> extract on ischaemia-reperfusion-induced hepatic DNA damage in rats

Hepatic ischaemia-reperfusion injury is a serious problem that occurs during various surgical operations such as liver transplantation, surgical revascularization, and partial organ resection. Different pharmacological agents have been used for the protection of organ function and for extending the tolerable ischaemic interval after the ischaemic insult. We aimed to determine the presence of 8-hydroxydeoxyguanosine (8-OHdG) in the DNA from liver undergoing ischaemia-reperfusion, and also to evaluate the protective effects of N-acetylcysteine (NAC) and EGb761 (Ginkgo biloba extract) against hepatic oxidative DNA damage. A total of 40 rats were divided into four groups of 10 animals each (sham-operation group, control group, NAC group, and EGb761 group). Oxidative damage to DNA was evaluated by measuring the increase in 8-OHdG formation in liver tissue and also the effects of NAC and EGb761 pretreatment. Hepatic ischaemia for 90 min followed by reperfusion caused a marked increase in tissue levels of 8-OHdG, thiobarbituric acid-reactive substance, serum ALT, AST and LDH activities compared to sham-operated group. Pretreatment with both NAC and EGb761 clearly diminished 8-OHdG formation and lipid peroxidation. These findings suggest that antioxidant molecules such as NAC and EGb761 may be useful in preventing postischaemic reperfusion injury in hepatic tissue.     

Antioxidant processes of the wild tambaqui, Colossoma macropomum (Osteichthyes, Serrasalmidae) from the Amazon.

Colossoma macropomum, locally called tambaqui, is a freshwater migratory teleost that shows good tolerance to oxygen and pH changes in water, and both chemical-physical parameters change markedly during the day time and seasonal water level oscillations in the Amazon Basin. In order to obtain a general view about the basal levels of antioxidants in different tissues of wild tambaqui, enzymatic (superoxide dismutase and catalase) and non-enzymatic (alpha-tocopherol, beta-carotene, and glutathione) antioxidants and lipid peroxidation levels were assessed in the liver, blood and plasma of ten specimens collected during the dry season (September) in a pond near Manaus-AM, Brazil. Superoxide dismutase, catalase, and lipid peroxidation levels were high in the liver and low in the blood and plasma. Confirming previous results on tambaqui, catalase was detected in the blood of one specimen only. beta-Carotene was not found in any analyzed tissue, while alpha-tocopherol was found only in the liver (7.8 +/- 7.0 nmol g(-1), mean +/- S.E.M.) and plasma (4.3 +/- 0.9 nmol ml(-1)). Blood glutathione concentrations (2.4 +/- 0.17 mmol l(-1)) of tambaqui were comparable with those found in other Amazonian teleosts. Antioxidant defenses and lipid peroxidation contents from liver. blood and plasma exhibited interesting correlations. These relationships suggest that antioxidant defenses located in different tissues and in different sub-cellular compartments act in concert.     

Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): Hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6

The hepatic ischemia-reperfusion syndrome was investigated in 28 patients undergoing elective partial liver resection with intraoperative occlusion of hepatic inflow (Pringle maneuver) using the technique of liver vein catheterization.

Hepatic venous oxygen saturation (ShvO₂) was monitored continuously up to 24 hours after surgery. Aspartate aminotransferase, glutamate dehydrogenase, γ-glutamyl transpeptidase, pseudocholinesterase, -glutathione S-transferase, reduced and oxidized glutathione, procalcitonine, and interleukin-6 were serially measured both before and after Pringle maneuver during the resection and postoperatively in arterial and/or hepatic venous blood.

ShvO₂ measurement demonstrated that peri- and postoperative management was suitable to maintain an optimal hepatic oxygen supply. As expected, we were able to demonstrate a typical enzyme pattern of postischemic liver injury. There was a distinct decrease of reduced glutathione levels both in arterial and hepatic venous plasma after LR accompanied by a strong increase in oxidized glutathione concentration during the phase of reperfusion. We observed increases in procalcitonin and interleukin-6 levels both in arterial and hepatic venous blood after declamping.

Our data support the view that liver resection in man under conditions of inflow occlusion resulted in ischemic lesion of the liver (loss of glutathione synthesizing capacity with disturbance of protection against oxidative stress) and an additional impairment during reperfusion (liberation of reactive oxygen species, local and systemic inflammation reaction with cytokine production). Additionally, we found some evidence for the assumption that the liver has an export function for reduced glutathione into plasma in man.     

Oxidative Stress-Related Biomarkers in Essential Hypertension and Ischemia-Reperfusion Myocardial Damage

Cardiovascular diseases are a leading cause of mortality and morbidity worldwide, with hypertension being a major risk factor. Numerous studies support the contribution of reactive oxygen and nitrogen species in the pathogenesis of hypertension, as well as other pathologies associated with ischemia/reperfusion. However, the validation of oxidative stress-related biomarkers in these settings is still lacking and novel association of these biomarkers and other biomarkers such as endothelial progenitor cells, endothelial microparticles, and ischemia modified albumin, is just emerging. Oxidative stress has been suggested as a pathogenic factor and therapeutic target in early stages of essential hypertension. Systolic and diastolic blood pressure correlated positively with plasma F2-isoprostane levels and negatively with total antioxidant capacity of plasma in hypertensive and normotensive patients. Cardiac surgery with extracorporeal circulation causes an ischemia/reperfusion event associated with increased lipid peroxidation and protein carbonylation, two biomarkers associated with oxidative damage of cardiac tissue. An enhancement of the antioxidant defense system should contribute to ameliorating functional and structural abnormalities derived from this metabolic impairment. However, data have to be validated with the analysis of the appropriate oxidative stress and/or nitrosative stress biomarkers.     

Ischemic preconditioning increases the tolerance of Fatty liver to hepatic ischemia-reperfusion injury in the rat

Hepatic steatosis is a major risk factor in ischemia-reperfusion. The present study evaluates whether preconditioning, demonstrated to be effective in normal livers, could also confer protection in the presence of steatosis and investigates the potential underlying protective mechanisms. Fatty rats had increased hepatic injury and decreased survival after 60 minutes of ischemia compared with lean rats. Fatty livers showed a degree of neutrophil accumulation and microcirculatory alterations similar to that of normal livers. However, in presence of steatosis, an increased lipid peroxidation that could be reduced with glutathione-ester pretreatment was observed after hepatic reperfusion. Ischemic preconditioning reduced hepatic injury and increased animal survival. Both in normal and fatty livers, this endogenous protective mechanism was found to control lipid peroxidation, hepatic microcirculation failure, and neutrophil accumulation, reducing the subsequent hepatic injury. These beneficial effects could be mediated by nitric oxide, because the inhibition of nitric oxide synthesis and nitric oxide donor pretreatment abolished and simulated, respectively, the benefits of preconditioning. Thus, ischemic preconditioning could be an effective surgical strategy to reduce the hepatic ischemia-reperfusion injury in normal and fatty livers under normothermic conditions, including hepatic resections, and liver transplantation.     

Mechanism of liver injury following ischemia.

To clarify whether ischemic liver injury is due to ischemia itself or reperfusion, histopathological and functional changes in the liver were examined before and after liver ischemia in rats with porto-systemic collateral channels. Effects of oxygen-derived free radical scavengers or an inhibitor of platelet aggregation on development of ischemic liver injury were also examined. Liver ischemia was produced by ligation of the portal vein and hepatic artery at liver hilum for 1 hr. The primary lesion of ischemic liver injury was cloudy swelling of liver cells in the periportal and midzonal regions; it developed during ischemia. The cloudy swelling of liver cells induced uneven distribution of sinusoidal blood flow after reperfusion, and consequently individual liver cell necrosis and focal hepatocellular necrosis in the midzonal regions developed later. Elevation of cytoplasmic enzyme activities in the serum after reperfusion was due to leakage across the damaged plasma membrane of liver cells. The treatment with superoxide dismutase, catalase, or heparin had not altered the liver injury that was attributed to ischemia, biochemically and histologically. These results suggest that ischemic liver injury is due to liver cell damage developed during ischemia, and that the ischemic liver injury is not alleviated or prevented by superoxide dismutase, catalase, or heparin.     

Time course of oxidative damage in different brain regions following transient cerebral ischemia in gerbils.

The time course of oxidative damage in different brain regions was investigated in the gerbil model of transient cerebral ischemia. Animals were subjected to both common carotid arteries occlusion for 5 min. After the end of ischemia and at different reperfusion times (2, 6, 12, 24, 48, 72, 96 h and 7 days), markers of lipid peroxidation, reduced and oxidized glutathione levels, glutathione peroxidase, glutathione reductase, manganese-dependent superoxide dismutase (MnSOD) and copper/zinc containing SOD (Cu/ZnSOD) activities were measured in hippocampus, cortex and striatum. Oxidative damage in hippocampus was maximal at late stages after ischemia (48-96 h) coincident with a significant impairment in glutathione homeostasis. MnSOD increased in hippocampus at 24, 48 and 72 h after ischemia, coincident with the marked reduction in the activity of glutathione-related enzymes. The late disturbance in oxidant-antioxidant balance corresponds with the time course of delayed neuronal loss in the hippocampal CA1 sector. Cerebral cortex showed early changes in oxidative damage with no significant impairment in antioxidant capacity. Striatal lipid peroxidation significantly increased as early as 2 h after ischemia and persisted until 48 h with respect to the sham-operated group. These results contribute significant information on the timing and factors that influence free radical formation following ischemic brain injury, an essential step in determining effective antioxidant intervention.     

Non-invasive measurement of hepatic oxygenation by an oxygen electrode in human orthotopic liver transplantation

Precise evaluation of graft reperfusion is difficult in clinical liver transplantation. The oxygen electrode (OE) is a novel technique to detect blood flow indirectly by measuring the quantity of oxygen which can diffuse from the hepatic tissue to the surface electrode. Application of the surface OE does not influence the liver blood flow or parenchymal perfusion. Adequate graft oxygenation is essential to the outcome of organ transplantation and has not previously been analysed intra-operatively in liver transplant recipients. The OE was applied to the surface of the graft intra-operatively in 22 human liver grafts after restoring portal vein and hepatic artery inflow. OE readings were compared with liver blood flow using an electromagnetic flowmeter (EMF). Intra-operative haemodynamics and donor organ parameters known to influence graft function were correlated with the OE readings. There was a significant correlation (r=0.89; p<0.001, n=14) between tissue oxygenation using the OE and total liver blood flow measured by EMF. The tissue oxygenation measurements were reproducible with a coefficient of variation of 5%. The hepatic tissue oxygenation increased significantly from baseline following venous reperfusion of the graft (282+/-23 vs 3107+/-288 (+/-SE) nA, p<0.001). Hepatic arterial revascularisation resulted in a significant (p<0.001) increase of 41+/-7% in liver oxygen perfusion. There was significant negative correlation (r=0.80, p<0.001, n=22) between cold ischaemic time and graft tissue oxygenation. The OE provides a reliable, cheap and non-invasive method of monitoring liver graft oxygenation and perfusion during transplantation.     

Effect of aging on intestinal ischemia and reperfusion injury

Intestinal ischemia/reperfusion (I/R) is a serious disorder that is prevalent in elderly patients. Reactive oxygen species are implicated in the pathogenesis of intestinal I/R injury. Reactive oxygen species are also implicated in cellular senescence and aging. To test the hypothesis that aging exacerbates intestinal I/R injury, the effects of intestinal I/R on tissue injury were compared between young (3 month old) and aged (12 month old) mice. Intestinal ischemia was induced by occluding the superior mesenteric artery with a microbulldog clamp. Reperfusion was initiated by removing the clamp. Mortality due to intestinal ischemia followed by reperfusion was significantly higher in aged mice. There were no differences in the baseline levels of malondialdehyde or myeloperoxidase activity (indicators of lipid peroxidation and neutrophil infiltration, respectively) between young and aged mice. Although intestinal I/R caused a significant increase in malondialdehyde levels and myeloperoxidase activity in aged mice, similar increases were also observed in young mice. There were no significant differences in the activities of antioxidant enzymes including superoxide dismutase, glutathione peroxidase and catalase between young and aged mice that underwent sham operation. Intestinal I/R caused a significant decrease in catalase activity only in aged mice. In conclusion, our results indicate that aged mice are more susceptible to mortality due to intestinal I/R and that an age-dependent decrease in catalase activity may contribute to the observed mortality.     

Hepatocytes are protected by herb Phyllanthus niruri protein isolate against thioacetamide toxicity.

The herb, Phyllanthus niruri has been known to possess protective activity against various drugs and toxins induced hepatic disorders. Present study was conducted to evaluate the role of the protein isolate of the herb against thioacetamide (TAA)-induced cytotoxicity in mice hepatocytes. In vitro cell viability, lactate dehydrogenase (LDH) and alanine amino transferase (ALT) leakage were measured as the indicators of cell damage. In addition, measurement of the level of non-protein thiol, glutathione (GSH); activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) as well as the extent of lipid peroxidation were carried out to evaluate the prooxidant-antioxidant status of the cell. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was performed to determine the radical scavenging activity of the protein isolate. Results showed that the administration of the protein isolate prior to TAA exposure significantly reduced the release of LDH and ALT leakage and enhanced the cell viability in a dose-dependent manner in hepatocytes. Besides, the protein isolate appeared to prevent the alterations in GSH levels and activities of the anti-oxidant enzymes related to prooxidant-antioxidant status of hepatocytes. It also reduced the TAA-induced lipid peroxidation significantly as demonstrated by the reduction of malondialdehyde (MDA) production. DPPH radical scavenging assay showed that the protein isolate possessed radical scavenging activity. Combining, the data suggest that the protein isolate could protect hepatocytes from TAA-induced cellular injury probably by its antioxidative and radical scavenging properties.