gamma-hydroxybutyrate protects the liver from warm ischemia-reperfusion injury in rat

BACKGROUND

Ischemia-reperfusion (I/R) syndrome remains an important clinical consideration in hepatic surgery, hemorrhagic shock, and liver transplantation. gamma-hydroxybutyrate (GHB) has been reported to exert protective effects against ischemia-reperfusion injury to various organs. To investigate whether GHB protects the liver from warm ischemia-reperfusion injury, we performed this study in rats.

METHODS

Thirty male Wistar rats were randomly divided into a sham-operation group, a control group,and three I/R groups pretreated with GHB, GHB plus naloxone or naloxone. After 30 minutes of partial ischemia, followed by 60 minutes of reperfusion in the liver, histomorphological and enzymological changes, lipid peroxidation, apoptosis, and the plasma level of endothelin-1 were observed.

RESULTS

I/R increased the serum levels of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase and the plasma level of endothelin-1 significantly (P<0.01), in addition to increase of apoptotic index (AI) from 0.28%+/-0.25% to 17.68%+/-1.91%. The levels of hepatic malondialdehyde were markedly increased, whereas the activities of superoxide dismutase were markedly decreased. GHB pretreatment prevented the liver from warm ischemia-reperfusion injury significantly, but naloxone partially blocked this effect.

CONCLUSION

GHB may significantly protect the liver from hepatic warm ischemia-reperfusion injury via several different mechanisms.

Direct evidence that induced nitric oxide production in hepatocytes prevents liver damage during lipopolysaccharide tolerance in rats

BACKGROUND

The role of nitric oxide (NO) in lipopolysaccharide (LPS) tolerance in the liver has been investigated in a number of previous studies, but it is still not clear whether NO is cytotoxic or cytoprotective. The aims of this study were to investigate whether low-dose LPS (LLPS)-induced hepatic production of NO is beneficial and to clarify the origins of cytoprotective NO-producing cells in the liver during LPS tolerance.

MATERIALS AND METHODS

Male Wistar rats received saline or LLPS intraperitoneally (i.p.; 0.01-1000 microg/kg) followed by a high dose of LPS (HLPS, 5 mg/kg) at various time intervals (4-16 h). NG-nitro-L-arginine methyl ester (L-NAME) was used to investigate the effects of inhibition of NOS. 4,5-Diaminofluorescein (DAF-2) was used to identify NO-producing cells in isolated liver cells in vitro. At various time points (4-16 h) after saline or LLPS (1 microg/kg, i.p.) injection, hepatocytes and Kupffer cells were isolated, incubated in 7 microm DAF-2 diacetate, and perfused with Krebs solution. Illumination at 495 nm revealed DAF-fluorescence (515 nm) in isolated cells under confocal laser fluorescence microscopy. The NO production in hepatocytes and Kupffer cells was assessed by the number of labeled cells per 1000 cells or per 100 cells, respectively.

RESULTS

Pretreatment with LLPS (0.1-100 microg/kg) resulted in a significant reduction (maximal at 8 h) of the HLPS-induced liver damage. L-NAME abolished the LLPS-induced protection. The NO production in hepatocytes was significantly increased and reached a maximum of 84% of all cells 8 h after LLPS administration. By contrast, the NO production in Kupffer cells remained constant at 95%, even following preinjection of LLPS.

CONCLUSION

LLPS-induced NO in hepatocytes, but not in Kupffer cells, exhibits cytoprotective effects on HLPS-induced liver damage, suggesting that NO has a beneficial role in the induction of the early phase of LPS tolerance.

Liver injury after intermittent or continuous hepatic pedicle clamping and its protection by reduced glutathione

BACKGROUND

The debate is still going on about selection of several clamping patterns during hepatectomy. The aim of this study was to assess the safety and preference of normothermic intermittent or continuous hepatic pedicle clamping and confirm the protective effect of reduced glutathione (GSH).

METHODS

Thirty-two adult male healthy Sprague-Dawley (SD) rats were divided into groups of intermittent clamping and GSH absent (IA), continuous clamping and GSH absent (CA), intermittent clamping and GSH present (IP) and continuous clamping and GSH present (CP). The clamping manners were successively 40 minutes in continuous clamping groups and two cycles of 20 minutes with an interval of 5 minutes in intermittent clamping groups, and reperfusion periods were 60 minutes. Experimental parameters included levels of malonaldehyde (MDA) and Cu/Zn superoxide dismutase (SOD), pathological and ultrastructural changes in liver tissues, activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in sera.

RESULTS

In the same group, the activities of ALT and AST were significantly higher in post-clamping rats than in pre-clamping rats (P<0.05), but no significant differences were noted in levels of MDA and Cu/Zn SOD (P>0.05). The differences of all values between post-reperfusion rats and pre-clamping rats were significant (P<0.05). Pathological and ultrastructural changes could be observed, but no irreversible injury was present. The comparison of the groups showed that the values at relevant time points between the intermittent and continuous groups were not significantly different (P>0.05). The values were significantly different between the GSH absent and present groups after reperfusion (P<0.05). The morphological damages were also obviously alleviated in the GSH present group.

CONCLUSIONS

Normothermic intermittent or continuous hepatic pedicle clamping could cause reversible liver ischemia/reperfusion injury when the clamping time lasts 40 minutes. The injury extent seems to be similar. Continuous clamping should be regarded as a proper method in liver surgery. GSH has been confirmed as an effective agent in preventing post-clamping liver injury.

[Liver and sports]

Physical exercise does not have harmful effects on liver, yet it can be an occasional cause of heat stroke in long-distance runners if they do not drink enough. Practicing sports does not have harmful liver effects as long as some risk behaviors are avoided such as consumption of anabolizers, sharing syringes or traveling to hepatitis endemic countries without being vaccinated. In patients with acute or chronic liver diseases, physical activity or practicing sports can be allowed as long as these do not lead to an excessive fatigue.

Ischemia-reperfusion injury of the human liver during hepatic resection

Haemorrhage during resection of the liver remains a significant threat to clinical outcome. Portal triad occlusion, with complete clamping of the hepatic inflow at the hepatoduodenal ligament, is a well-documented, safe, and useful means of alleviating this problem. Although this technique is effective in limiting blood loss, there is still controversy concerning the potential drawbacks of ischemia and subsequent reperfusion injury of the liver. This article highlights recent advances in our understanding of the clinical factors influencing ischemia-reperfusion injury of the liver, particularly in human patients. These factors include the cell components involved, the mechanisms that enable the human liver to tolerate long-term inflow occlusion, factors affecting clinical outcomes, and surgical and pharmacological techniques used to alleviate ischemia-reperfusion injury, including hypothermic hepatectomy.

Ischemia and hepatic reperfusion: is it possible to reduce hepatic alterations?

Our aim was to evaluate liver damage after ischemia and reperfusion, and at the same time test the effectiveness of some drugs in preventing these alterations. For this study, we utilized 50 rats divided into four groups: three underwent hepatic ischemia through occlusion of the portal vein and hepatic artery for 30 min, and one underwent a sham operation. In all groups, hepatic enzymes and bilirubine were tested at 2 h, 3 h, 4 h, 24 h, and 30 h. The drugs utilized were: L-arginine, donor of nitric oxide, and L-canavanine, inhibitor of nitric oxide synthase (NOS). Our data showed that the drugs tested could make an improvement in hepatic function after ischemia/reperfusion, preventing its damage. These preliminary results could suggest a clinical application in order to prolong ischemic period during liver transplantation or liver resection in cirrhotic patients.

Clinical management. Where medicine meets management. Can of worms

There have been massive increases in the incidence of liver diseases in the UK, reaching epidemic levels. The development of liver services has been haphazard and there is no national service framework for liver disease, endangering patients. Specialist groups have formulated a national plan setting standards and guidelines.

Ingestion of resistant starch protects endotoxin influx from the intestinal tract and reduces D-galactosamine-induced liver injury in rats

BACKGROUND AND AIMS

The aim of the present study was to examine the protective effect of a dietary high-amylose cornstarch (HAS) against D-galactosamine (D-GalN)-induced liver injury, focusing specifically on intestinal endotoxin translocation.

METHODS

Male Wistar rats fed a HAS-free basal diet or a 30% HAS-supplemented diet were injected intraperitoneally with D-GalN. Serum transaminase activities, serum concentrations of tumor necrosis factor (TNF)-alpha, and portal venous endotoxin concentrations were determined at various time points. Ileal mucosal proliferation, small intestinal immunoglobulin (Ig)A and mucin, and the size of the cecal short-chain fatty acids (SCFA) pool were also determined.

RESULTS

High-amylose cornstarch ingestion significantly reduced the increase in serum transaminase activities at 22 h after the injection of D-GalN. Rats fed the HAS diet showed a greater cecal SCFA production as measured by pool size than those fed the basal diet. Luminal IgA and mucin content were significantly greater in rats fed the HAS diet. Protein, DNA and RNA contents in the ileal mucosa were also higher in rats fed the 30% HAS diet. In a further experiment, portal venous endotoxin concentrations in rats fed the basal diet reached 72 ng/L at 4 h after D-GalN administration, but endotoxin was not detected in rats fed the HAS diet. At this time, portal endotoxin concentrations were significantly and positively correlated with the serum concentrations of TNF-alpha and serum alanine aminotransferase activities.

CONCLUSION

These data support the view that HAS ingestion may reduce D-GalN-induced liver injury as a result of an inhibitory effect on endotoxin influx from the intestinal tract, at least in part as a result of alterations in the mucosal barrier functions.

Managing hepatitis C

Availability of a drug regimen that eradicates the hepatitis C virus (HCV) in more than half of treated patients provides the medical community with a powerful new weapon to diminish the anticipated future wave of HCV-related liver disease and cancer. Clinicians must understand the benefits, risks, and costs associated with the combination of peginterferon alfa and ribavirin. Major clinical trials with this new standard of HCV therapy have demonstrated sustained virologic responses of 54% and 56% with 48 weeks of combination therapy. Response is highest in those with genotype 2/3, with early virologic response by week 12, in patients with high adherence, and in patients receiving weight-appropriate ribavirin dosages. The most common side effects are manageable and include fatigue, headache, myalgia, rigors, fever, nausea, insomnia, and depression. Neutropenia associated with interferon and anemia associated with ribavirin are more serious side effects that can cause discontinuation or dose reduction. Clinicians can maximize results and reduce costs with a regimen of peginterferon alfa plus ribavirin by choosing patients carefully, educating patients thoroughly, stopping therapy early in those patients who do not respond by week 12 of therapy, and enhancing adherence by managing side effects with appropriate dose reductions and/or selective use of antidepressants or hematopoietic colony stimulators.

Irreversible intestinal failure

Intestinal failure (IF) can be defined as the reduction of functional gut mass below the minimal amount necessary for digestion and absorption adequate to satisfy the nutrient and fluid requirements for maintenance in adults or growth in children. In developed countries, IF mainly includes individuals with the congenital or early onset of conditions requiring protracted or indefinite parenteral nutrition (PN). Short bowel syndrome was the first commonly recognized cause of protracted IF. The normal physiologic process of intestinal adaptation after extensive resection usually allows for recovery of sufficient intestinal function within weeks to months. During this time, patients can be sustained on parenteral nutrition. Only a few children have permanent intestinal insufficiency and life-long dependency on PN. Non-transplant surgery including small bowel tapering and lengthening may allow weaning from PN in some cases. Hormonal therapy with recombinant human growth hormone has produced poor results while therapy with glucagon-like peptide-2 holds promise. Congenital diseases of enterocyte development such as microvillus inclusion disease or intestinal epithelial dysplasia cause permanent IF for which no curative medical treatment is currently available. Severe and extensive motility disorders such as total or subtotal intestinal aganglionosis (long segment Hirschsprung disease) or chronic intestinal pseudo-obstruction syndrome may also cause permanent IF. PN and home-PN remain are the mainstays of therapy regardless of the cause of IF. Some patients develop complications while receiving long-term PN for IF especially catheter related complications (thrombosis, sepsis) and liver disease. These patients may be candidates for intestinal transplantation. This review discusses the causes of irreversible IF and emphasizes the specific medico-surgical strategies for prevention and treatment of these conditions at several stages of IF.

The hydroxyl radical scavenger MCI-186 protects the liver from experimental cold ischaemia-reperfusion injury

BACKGROUND

Oxidative stress contributes to hepatic ischaemia-reperfusion (IR) injury in a biphasic pattern. In addition to direct cytotoxic effects, oxidative stress also initiates the signal transduction processes that promote second-phase liver injury. The present study investigated the effects of the hydroxyl radical scavenger MCI-186 on the biphasic process of hepatic cold IR injury.

METHODS

After cold preservation for 16 h, rat livers were reperfused on an isolated liver perfusion system for 120 min with oxygenated Krebs-Henseleit bicarbonate buffer. Perfusate samples were obtained serially, and portal flow rates were also recorded. To determine whether MCI-186 affected cytokine levels that control the second-phase injury, levels of interleukin (IL) 10 and tumour necrosis factor (TNF) alpha were measured in the perfusate.

RESULTS

Addition of MCI-186 1 mg/l into the perfusate significantly improved portal flow (P<0.050), hepatic enzyme release into the perfusate (P=0.038), total bile production (P=0.029) and malondialdehyde concentration (P=0.038). Furthermore, treatment with MCI-186 led to a substantial increase in IL-10 release (P=0.032). TNF-alpha levels were not affected.

CONCLUSIONS

MCI-186, an agent ready for clinical use, appears to have direct and indirect protective effects against hepatic cold IR injury.

Antioxidant action of Moringa oleifera Lam. (drumstick) against antitubercular drugs induced lipid peroxidation in rats

The protective effect of Moringa oleifera Lam. (Moringaceae) on hepatic marker enzymes, lipid peroxidation, and antioxidants was investigated during antitubercular drug (isoniazid, rifampicin, and pyrazinamide)-induced toxicity in rats. Enhanced hepatic marker enzymes and lipid peroxidation of antitubercular drug treatment was accompanied by a significant decrease in the levels of vitamin C, reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase. Administration of Moringa oleifera extract and silymarin significantly decreased hepatic marker enzymes and lipid peroxidation with a simultaneous increase in the level of antioxidants. We speculate that Moringa oleifera extract exerts its protective effects by decreasing liver lipid peroxides and enhancing antioxidants.

Endogenous ligands of PPAR-γ reduce the liver injury in haemorrhagic shock

We demonstrate here for the first time that the novel, potent peroxisome proliferator-activated receptor (PPAR)-gamma antagonist GW9662 (2-chloro-5-nitrobenzanilide) augments the degree of liver injury associated with haemorrhagic (haemorrhage for 90 min and resuscitation for 4 h), but not endotoxic (6 mg/kg E. coli endotoxin i.v. for 6 h) shock in the anaesthetised rat. Thus, endogenous ligands for PPAR-gamma are released in haemorrhagic, but not endotoxic, shock in sufficient amounts to protect against injury.

The Value of N-Acetylcysteine in the Prevention of Radiocontrast Agent-Induced Nephropathy Seems Questionable

Prevention of contrast agent-induced nephropathy is of crucial importance for a number of diagnostic studies. N-Acetylcysteine (NAC) was recently reported to decrease serum creatinine levels in this setting, and its administration before radiocontrast medium administration has been widely recommended. The objective of this prospective study was to investigate whether there are effects of NAC on serum creatinine levels that are independent of alterations in GFR. Volunteers with normal renal function who did not receive radiocontrast medium were studied. Fifty healthy volunteers completed the study protocol. NAC was administered orally at a dose of 600 mg every 12 h, for a total of four doses. Surrogate markers of renal function, such as serum creatinine, urea, albumin, and cystatin C levels, were measured and estimated GFR (eGFR) was assessed immediately before the administration of NAC and 4 and 48 h after the last dose. There was a significant decrease in the mean serum creatinine concentration (P < 0.05) and a significant increase in the eGFR (P < 0.02) 4 h after the last dose of NAC. The cystatin C concentrations did not change significantly. In several studies, a protective effect of NAC on renal function after radiocontrast medium administration has been postulated. This is the first study to demonstrate an effect of NAC on creatinine levels and eGFR, surrogate markers of renal injury, without any effect on cystatin C levels. Before renoprotective effects of NAC against contrast agent-induced nephropathy are considered, the direct effects of NAC on creatinine levels, urea levels, and eGFR should be assessed.

Protective effects of lidocaine injected into the hepatoduodenal ligament on warm ischemia-reperfusion injury to the rat liver

BACKGROUND

Ischemia-reperfusion (IR) injury to the liver is still a critical and daunting problem in the field of hepatobiliary surgery. Ischemic preconditioning (IP) of the liver serves as an effective approach against IR injury. This study was to develop a novel procedure that could mimic IP, but might be more feasible than IP during surgery.

METHODS

Eighty-two SD rats were randomly divided into 5 groups. L group (n = 21): 0.4% lidocaine (10 mg/kg) was injected into the hepatoduodenal ligament 10 minutes before a 40-minute hepatic IR. IP group (n = 16): a 5-minute ischemia was followed by a 10-minute reperfusion prior to a 40-minute hepatic IR. ILR group (n = 15): after a 40-minute ischemia of the liver, 0.4% lidocaine (10 mg/kg) was injected into the hepatoduodenal ligament 10 minutes prior to a 40-minute reperfusion of the liver. IR group (n = 15): the liver of the rat was subjected to a 40-minute IR. Control group (n = 15): 0.9% sodium chloride was injected into the hepatoduodenal ligament without other treatments. The levels of plasma alanine transaminase (ALT) and aspartate transaminase (AST) were determined for each group after treatment.

RESULTS

The mean concentrations of ALT and AST were (379.80 +/- 141.69) U/L and (606.05 +/- 220.26) U/L for the L group, (334.64 +/- 141.94) U/L and (625.68 +/- 267.06) U/L for the IP group, (523.36 +/- 170.35) U/L and (765.47 +/- 238.45) U/L for the ILP group, (524.29 +/- 163.59) U/L and (764.63 +/- 246.79) U/L for the IR group, and (150.90 +/- 27.05) U/L and (298.15 +/- 47.68) U/L for the control group (standard error of the mean).

CONCLUSION

A significant decrease in ALT and AST levels was observed in the L and IP groups when compared to the ILR and IR groups (P < 0.05), but no significant difference in ALT and AST levels was observed in the L group when compared to the IP group (P > 0.05). These results suggest that pretreatment with lidocaine injected into the hepatoduodenal ligament prior to IR provides effective protection against subsequent IR injury to the liver. The novel approach of blocking innervation with lidocaine mimics hepatic IP, but is more convenient than IP at the time of liver surgery.

Gene therapy for liver transplantation using adenoviral vectors: CD40-CD154 blockade by gene transfer of CD40Ig protects rat livers from cold ischemia and reperfusion injury

Liver injury induced by ischemia/reperfusion (I/R) is the prime factor in delayed or loss graft function following transplantation. CD4+ T lymphocytes are key cellular mediators of antigen-independent inflammatory response triggered by I/R. We attempted to modulate rat liver I/R injury by targeted gene therapy with CD40Ig, which blocks the CD40-CD154 costimulation pathway. One hundred percent of Ad-CD40Ig-pretreated orthotopic liver transplants (OLTs) subjected to 24 h of cold (4 degrees C) ischemia survived > 14 days (vs 50% in untreated/Ad-beta-gal groups). Ad-CD40Ig treatment decreased sGOT levels and depressed neutrophil infiltration, compared with controls. These functional data correlated with histological Suzuki's grading of hepatic injury, which in untreated/Ad-beta-gal groups showed severe necrosis (> 60%) and moderate to severe sinusoidal congestion; the Ad-CD40Ig-pretreated group revealed minimal sinusoidal congestion/necrosis. Unlike in controls, OLT expression of mRNA coding for IL-2/IFN-gamma remained depressed, whereas that of IL-4/IL-13 reciprocally increased in the Ad-CD40Ig group. Ad-CD40Ig reduced frequency of TUNEL+ cells and pro-apoptotic Caspase-3, but enhanced antioxidant HO-1 and anti-apoptotic Bcl-2/Bcl-xl expression. Thus, prolonged blockade of CD40-CD154 by CD40Ig exerts potent cytoprotection against hepatic I/R injury. These results provide the rationale for a novel gene therapy approach to maximize the organ donor pool through the safer use of liver transplants exposed to prolonged cold ischemia.

Pirfenidone prevents endotoxin-induced liver injury after partial hepatectomy in rats

BACKGROUND/AIMS

Massive liver resection causes a variety of complications including endotoxemia. Pirfenidone (PFD) is a new experimental drug used as antifibrotic agent. Studies were performed to investigate whether PFD influences the survival rate of animals with endotoxin-induced liver injury after partial hepatectomy, and the mechanisms involved.

METHODS

Rats were treated with lipopolysaccharide (LPS) 48 h after 70% hepatectomy. PFD was administered orally before LPS injection.

RESULTS

PFD improved the survival rate of LPS-treated rats after hepatectomy. PFD prevented increases in serum enzymes and total bilirubin related to liver injury. Histopathological analysis revealed that PFD inhibited the enhancement in hepatic necrosis and apoptosis. Further, PFD inhibited increases of inflammatory cytokines and cytokine-induced neutrophil chemoattractant (CINC) in serum and liver, followed by decreases of number of infiltrating neutrophils into liver. Electrophoretic mobility shift assay revealed that PFD inhibited the activation of transcription factor nuclear factor-kappa B (NF-kappa B) induced by LPS. PFD also reduced the induction of inducible nitric oxide synthase (iNOS) in the liver of LPS-treated rats.

CONCLUSIONS

These results indicate that PFD inhibits the productions of inflammatory cytokines, CINC and iNOS in part through the inhibition of NF-kappa B activation, resulting in the prevention of endotoxin-induced liver injury after hepatectomy.

[Liver hemangioma: the need for a well-defined differential diagnosis and the therapeutical timing dilemma]

Liver is frequently affected by hemangiomas originated during the embryonal period from defects in the maturation of the endothelia of the capillary system. These benign tumors may result asymptomatic for the whole life (4-7% of incidental autoptical reports), but in some cases they are liable to a spontaneous or traumatic rupture, with haemorrhagic complications which make an urgent laparotomy necessary. The rupture may be caused by different reasons, such as the critical size reached by the endothelia, the development of the mass due to the continuous pulsatility or the hormonal stimuli (puberty, pregnancy or oral contraceptives).

The role of calcium and calcium channel blocking drugs in damage to the liver preserved for transplantation

Calcium plays a crucial role in physiological process in liver cells however in high concentrations these ions can be pathogenic and lead to cell death. Mechanisms responsible for maintaining calcium ion concentration gradient in physiological conditions include transmembrane transport, storage in intracellular organelles and binding to cytoplasmatic proteins. Ischemia, sepsis, anoxia and action of toxins are responsible for uncontrolled influx of calcium and consequently cell damage. Liver damage during its preservation for transplantation is connected with dysfunction of many enzymes, damage of cell membrane and cytoskeleton proteins. During reperfusion Kupffer cells are activated, reactive oxygen species are produced and microcirculation is disordered by calcium--dependent processes. Calcium channel blocking (CCB) drugs exhibit immunomodulatory impact and positive interaction with cyclosporine or tacrolismus. They also have cytoprotective properties during preservation end reperfusion time. They seem to improve liver function, decrease liver cell damage, elevate bile production, decrease lipid peroxydation and free radicals production. But in some experiments CCB do not modify calcium concentration. More research on preservation conditions is needed to increase the probability of a successful liver transplantation.

Hepatoprotective properties of Commiphora opobalsamum ("Balessan"), a traditional medicinal plant of Saudi Arabia

The hepatoprotective activity of an ethanolic extract of Commiphora opobalsamum ("Balessan") was investigated in rats by inducing hepatotoxicity with carbon tetrachloride:liquid paraffin (1:1). This extract has been shown to possess significant protective effect by lowering serum transaminase levels (serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase), alkaline phosphatase and bilirubin. Pretreatment with an extract of Balessan prevented the prolongation of the barbiturate sleeping time associated with carbon tetrachloride-induced liver damage in mice. On the other hand, CCl4-induced low-level nonprotein sulfhydryl concentration in the liver was replenished by the Balessan extract. These data suggest that the plant C. opobalsamum may act as an antioxidant agent and may have a hepatoprotective effect.

Melatonin inhibits nuclear factor kappa B activation and oxidative stress and protects against thioacetamide induced liver damage in rats

BACKGROUND/AIMS

Free radical-mediated oxidative stress has been implicated in the pathogenesis of acute liver injury. The aim of our study was to investigate whether melatonin, a potent free radical scavenger could prevent fulminant hepatic failure in rats.

METHODS

Liver damage was induced by two consecutive injections of thioacetamide (TAA, 300 mg/kg/i.p.) at 24 h intervals. Treatment with melatonin (3 mg/kg/daily, i.p) was initiated 24 h prior to TAA.

RESULTS

Twenty-four h after the second TAA injection, serum liver enzymes and blood ammonia were lower in rats treated with TAA+melatonin compared to TAA (P<0.001). Liver histology was significantly improved and the mortality in the melatonin-treated rats was decreased (P<0.001). The increased nuclear binding of nuclear factor kappa B in the livers of the TAA-treated rats, was inhibited by melatonin. The hepatic levels of thiobarbituric acid reactive substances, protein carbonyls and inducible nitric oxide synthase were lower in the TAA+melatonin-treated group (P<0.01), indicating decreased oxidative stress and inflammation.

CONCLUSIONS

In a rat model of TAA-induced fulminant hepatic failure, melatonin improves survival and reduces liver damage and oxidative stress. The results suggest a causative role of oxidative stress in TAA-induced hepatic damage and suggest that melatonin may be utilized to reduce liver injury associated with oxidative stress.

Sesame oil protects against lipopolysaccharide-stimulated oxidative stress in rats

OBJECTIVE

The aim of this study was to determine the effects and the defense mechanisms of sesame oil on lipopolysaccharide-induced oxidative stress in rats.

DESIGN

Laboratory in vivo study of the effect of sesame oil on lipid peroxide, superoxide anion, superoxide dismutase, catalase, glutathione, and nitrite concentrations. To assess the effect of sesame oil on hepatic function, we determined serum aspartate aminotransferase, total bilirubin, and liver histology.

SETTING

University laboratory.

SUBJECTS

Male SPF Wistar rats.

INTERVENTIONS

Blood testing, administration of oils, and liver biopsies.

MEASUREMENTS AND MAIN RESULTS

Oxidative stress induced by lipopolysaccharide (5 mg/kg, intraperitoneally) was assessed by determination of lipid peroxidation. Sesame oil was given orally immediately after lipopolysaccharide administration, and lipid peroxidation concentrations were determined. The reactive oxygen species superoxide anion was measured by chemiluminescence analyzer. The enzyme activities of superoxide dismutase and catalase and the concentrations of glutathione and nitrite also were determined. Hepatic injury was evaluated by determining the concentrations of serum aspartate aminotransferase and total bilirubin and by liver histologic examination. Sesame oil significantly reduced lipid peroxidation but failed to affect nitrite concentrations in lipopolysaccharide-treated rats. Superoxide anion counts were decreased, and glutathione, but not superoxide dismutase or catalase, was increased in sesame oil-treated groups with lipopolysaccharide-induced oxidative stress. Only sesame oil-treated groups, but not corn oil- or mineral oil-treated groups, showed attenuated hepatic disorder induced by lipopolysaccharide. In addition, sesame oil given 6 hrs after lipopolysaccharide also attenuated lipid peroxidation and hepatic disorder. Furthermore, sesame oil given immediately or 6 hrs after lipopolysaccharide administration significantly reduced morphologic changes induced by lipopolysaccharide.

CONCLUSION

A single dose of sesame oil may attenuate oxidative stress and subsequently relieve hepatic disorder in endotoxemic rats.

Factors affecting patient-physician communication via the Internet

Patients with chronic diseases would potentially benefit greatly from more rapid communication with their health provider of their medical status, healthcare concerns, and personal medical information such as vital signs, blood sugar, and medication use. This study surveyed patients in a multidisciplinary transplant and liver disease clinic to determine whether they would consider using an Internet-based system for medical management of their illness, what specific factors would impact their use of such a system, and what limitations might be encountered with respect to patient education, socioeconomic status, and Internet access.

Protective effect of arabic gum against acetaminophen-induced hepatotoxicity in mice

Overdose of acetaminophen, a widely used analgesic drug, can result in severe hepatotoxicity and is often fatal. This study was undertaken to examine the effects of arabic gum (AG), which is commonly used in processed foods, on acetaminophen-induced hepatotoxicity in mice. Mice were given arabic gum orally (100 g l(-1)) 5 days before a hepatotoxic dose of acetaminophen (500 mg kg(-1)) intraperitoneally. Arabic gum administration dramatically reduced acetaminophen-induced hepatotoxicity as evidenced by reduced serum alanine (ALT) and aspartate aminotransferase (AST) activities. Acetaminophen-induced hepatic lipid peroxidation was reduced significantly by arabic gum pretreatment. The protection offered by arabic gum does not appear to be caused by a decrease in the formation of toxic acetaminophen metabolites, which consumes glutathione, because arabic gum did not alter acetaminophen-induced hepatic glutathione depletion. Acetaminophen increased nitric oxide synthesis as measured by serum nitrate plus nitrite at 4 and 6 h after administration and arabic gum pretreatment significantly reduced their formation. In conclusion, arabic gum is effective in protecting mice against acetaminophen-induced hepatotoxicity. This protection may involve the reduction of oxidative stress.