allopurinol and Fatty-Liver

Allopurinol is an inhibitor of xanthine oxidoreductase (XOR) and inhibits the generation of uric acid (UA) as the final product of purine catabolism, as well as the resulting generation of superoxide (O2(-)), in humans. Elevation of the serum UA (SUA) level, referred to as hyperuricemia (HU), eventually leads to gout and allopurinol has been used for the treatment of HU and gout. Studies have revealed the role of elevated SUA levels and the associated oxidative stress (OS) in a broad spectrum of pathological conditions and it is anticipated that these findings would also expand the use of allopurinol as a therapeutic drug. This article presents a review of reports, mainly of recent studies, on the efficacy of allopurinol in various diseases and explores novel potential uses of the drug. Important novel and potential uses of great interest include metabolic syndrome (MetS) and related disorders, chronic kidney disease (CKD), nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Ischemia-reperfusion injury and mucositis, encountered as adverse effects of cancer treatment, have also been under investigation as potential targets for allopurinol.

Topics: Allopurinol; Enzyme Inhibitors; Fatty Liver; Humans; Liver Diseases; Metabolic Syndrome; Mucositis; Renal Insufficiency, Chronic; Reperfusion Injury; Uric Acid; Xanthine Dehydrogenase

Topics: Allopurinol; Anemia, Pernicious; Animals; Azauridine; Carboxy-Lyases; Fatty Liver; Female; Humans; Infant, Newborn; Jaundice, Neonatal; Lipids; Metabolic Diseases; Metabolism, Inborn Errors; Milk; Myocardial Infarction; Ornithine Carbamoyltransferase; Orotic Acid; Pentosyltransferases; Pregnancy; Uric Acid

Topics: Adenosine; Adult; Allopurinol; Fatty Liver; Glutathione; Humans; Insulin; Isotonic Solutions; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Prospective Studies; Raffinose; Ringer's Lactate; Solutions; Tissue Donors

Reactive oxygen species (ROS) metabolism is regulated by the oxygen-mediated enzyme reaction and antioxidant mechanism within cells under physiological conditions. Xanthine oxidoreductase (XOR) exhibits two inter-convertible forms (xanthine oxidase (XO) and xanthine dehydrogenase (XDH)), depending on the substrates. XO uses oxygen as a substrate and generates superoxide (O

Topics: Acetophenones; Aging; Allopurinol; Anemia; Animals; Fatty Liver; Mice, Mutant Strains; Muscular Atrophy; NADPH Oxidases; Superoxide Dismutase-1; Superoxides; Xanthine Dehydrogenase

The incidence of metabolic associated fatty liver disease (MAFLD) induced by high fructose consumption is dramatically increasing in the world while lacking specifically therapeutic drugs. The present study aimed to investigate the effect of complement C1q/tumor necrosis factor-related protein-3 (CTRP3) on fructose-induced MAFLD and its potential mechanisms.. The animal models with MAFLD were built with Sprague-Dawley (SD) rats drinking 10 % fructose solution for 12 weeks. Then, specific hepatic CTRP3 overexpression was conducted by a single caudal-vein injection of CTRP3-expressing adenoviruses. Rats were sacrificed two weeks later.. Drinking 10 % fructose solution for 12 weeks successfully built the rats models with MAFLD. Fructose feeding markedly decreased hepatic CTRP3 expression in rats. However, CTRP3 overexpression in liver alleviated hyperuricemia, dyslipidemia, liver function injury, intrahepatic triglyceride (TG) accumulation and histological changes of hepatic steatosis in rats fed with fructose. CTRP3 overexpression also inhibited hepatic XO activity in liver and improved subsequent oxidative stress, accompanied with downregulation of gene expression of sterol-regulatory element binding protein 1c (SERBP-1c) and fatty acid synthase (FAS).. CTRP3 attenuates MAFLD induced by fructose, which maybe partially attribute to rescued oxidative stress related with xanthine oxidase overactivity.

Topics: Adipokines; Animals; Fatty Acid Synthases; Fatty Liver; Feeding Behavior; Fructose; Lipids; Male; Oxidative Stress; Rats, Sprague-Dawley; RNA, Messenger; Sterol Regulatory Element Binding Protein 1; Uric Acid; Xanthine Oxidase

Hyperuricemia drives the development of nonalcoholic fatty liver disease (NAFLD). Pharmacological inhibition of xanthine oxidase (XO), a rate-limiting enzyme for uric acid (UA) production, has been demonstrated to improve hepatic steatosis in diet-induced obese mice. However, it remains unclear whether inhibition of XO improves nonalcoholic steatohepatitis (NASH), a more advanced form of NAFLD, in terms of both liver inflammation and fibrosis. Here, we investigated the effects of febuxostat and allopurinol, two XO inhibitors clinically used for gout, on a mouse model of NASH. Furthermore, we conducted a single-arm, open-label intervention study with febuxostat for NAFLD patients with hyperuricemia. Despite a similar hypouricemic effect of the XO inhibitors on blood UA level, febuxostat, but not allopurinol, significantly decreased hepatic XO activity and UA levels in the NASH model mice. These reductions in hepatic XO activity and UA levels were accompanied by attenuation of insulin resistance, lipid peroxidation, and classically activated M1-like macrophage accumulation in the liver. Furthermore, in NAFLD patients with hyperuricemia, treatment with febuxostat for 24 weeks decreased the serum UA level, accompanied by reductions in the serum levels of liver enzymes, alanine aminotransferase and aspartate aminotransferase. XO may represent a promising therapeutic target in NAFLD/NASH, especially in patients with hyperuricemia.

Topics: Allopurinol; Animals; Diet, High-Fat; Disease Models, Animal; Fatty Liver; Febuxostat; Hyperuricemia; Insulin Resistance; Lipid Peroxidation; Liver; Macrophage Activation; Mice, Inbred C57BL; Molecular Targeted Therapy; Uric Acid; Xanthine Oxidase

Febuxostat has superior renal safety to allopurinol, but data on its hepatic safety are limited. Thus we compared the hepatotoxicity of febuxostat and allopurinol, and the clinical factors associated with hepatotoxicity, in patients with gout and fatty liver disease (FLD).. We included gout patients treated with allopurinol or febuxostat who were diagnosed with fatty liver based on ultrasonography or computed tomography. Hepatotoxicity was defined as follows: (1) elevation of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) at least 3× the upper limit of normal, when the baseline AST/ALT was normal; or (2) doubling of the baseline AST/ALT, when the baseline AST/ALT was elevated. The factors associated with hepatotoxicity were evaluated by Cox regression analysis.. Of 134 patients identified with gout and FLD, 32 (23.9%) received febuxostat and 102 (76.1%) received allopurinol. There were no significant differences in age, body mass index, comorbidity, or disease severity between the groups; however, the incidence of hepatotoxicity was significantly lower in the febuxostat group (3/32, 9.4%) than in the allopurinol group (36/102, 35.3%, p = 0.005). Diabetes (HR 3.549, 95% CI 1.374-9.165, p = 0.009) and colchicine use (HR 11.518, 95% CI 5.515-24.054, p < 0.001) were associated with a higher risk of hepatotoxicity, whereas febuxostat use was associated with a lower risk of hepatotoxicity (HR 0.282, 95% CI 0.086-0.926, p = 0.037).. In the 32 patients studied, febuxostat was well tolerated in patients with gout and FLD. However, the presence of diabetes and colchicine use may increase the risk of hepatotoxicity.

Topics: Adult; Allopurinol; Analysis of Variance; Cohort Studies; Comorbidity; Dose-Response Relationship, Drug; Drug Administration Schedule; Fatty Liver; Febuxostat; Female; Gout; Gout Suppressants; Humans; Liver; Liver Function Tests; Male; Middle Aged; Multivariate Analysis; Prognosis; Retrospective Studies; Risk Assessment; Tomography, X-Ray Computed; Treatment Outcome; Ultrasonography, Doppler

To compare liver proteolysis and proteasome activation in steatotic liver grafts conserved in University of Wisconsin (UW) and Institut Georges Lopez-1 (IGL-1) solutions.. Fatty liver grafts from male obese Zücker rats were conserved in UW and IGL-1 solutions for 24 h at 4 °Cand subjected to ". Our comparison of these two preservation solutions suggests that IGL-1 helps to prevent ATP breakdown more effectively than UW and subsequently achieves a higher UPS inhibition and reduced liver proteolysis.

Topics: Adenosine; Allopurinol; Animals; Apoptosis; Autophagy; Chromatography, High Pressure Liquid; Chymotrypsin; Fatty Liver; Glutathione; Graft Survival; Homozygote; Inflammation; Insulin; Liver; Liver Transplantation; Male; Mitochondria; Organ Preservation; Organ Preservation Solutions; Perfusion; Proteasome Endopeptidase Complex; Proteolysis; Raffinose; Rats; Rats, Zucker

Donation after cardiac death (DCD) livers are considered to be marginal organs for solid organ and cell transplantation. Low energy charge (EC) and low purine quantity within the liver parenchyma has been associated with poor outcome after liver transplantation. The aim of this work was to assess the effect of anterograde persufflation (A-PSF) using an electrochemical concentrator on DCD liver energy status and hepatocyte function. Organs utilized for research were DCD livers considered not suitable for transplant. Each liver was formally split, and the control non-persufflated (non-PSF) section was stored in University of Wisconsin (UW) solution at 4°C. The A-PSF liver section was immersed in UW solution on ice, and A-PSF was performed via the portal vein with 40% oxygen. Tissue samples were taken 2 hours after A-PSF from the A-PSF and control non-PSF liver sections for snap freezing. Purine analysis was performed with photodiode array detection. Hepatocytes were isolated from A-PSF and control non-PSF liver sections using a standard organs utilized for research were DCD livers considered not suitable for transplant collagenase perfusion technique. Hepatocyte function was assessed using mitochondrial dehydrogenase activity {3-[4,5-dimethylthiazol-2-y1]-2,5-diphenyl tetrazolium bromide (MTT)} and the sulforhodamine B (SRB) assay for cell attachment. In DCD livers with <30% steatosis (n = 6), A-PSF increased EC from 0.197 ± 0.025 to 0.23 ± 0.035 (P = 0.04). In DCD livers with >30% steatosis (n = 4), A-PSF had no beneficial effect. After isolation (n=4, <30% steatosis), A-PSF was found to increase MTT from 0.92 ± 0.045 to 1.19 ± 0.55 (P < 0.001) and SRB from 2.53 ± 0.12 to 3.2 ± 0.95 (P < 0.001). In conclusion, A-PSF can improve the EC and function of isolated hepatocytes from DCD livers with <30% steatosis.

Topics: Adenosine; Aged; Allopurinol; Cold Temperature; Donor Selection; Energy Metabolism; Fatty Liver; Gases; Glutathione; Heart Diseases; Hepatocytes; Humans; Insulin; Middle Aged; Organ Preservation; Organ Preservation Solutions; Oxygen; Perfusion; Purines; Raffinose; Severity of Illness Index; Time Factors; Tissue and Organ Harvesting; Tissue Donors

Hepatic steatosis is a major risk factor for graft failure in liver transplantation. Hepatic steatosis shows a greater negative influence on graft function following prolonged cold ischaemia. As the impact of steatosis on hepatocyte metabolism during extended cold ischaemia is not well-described, we compared markers of metabolic capacity and mitochondrial function in steatotic and lean livers following clinically relevant durations of cold preservation.. Livers from 10-week old leptin-deficient obese (ob/ob, n = 9) and lean C57 mice (n = 9) were preserved in ice-cold University of Wisconsin solution. Liver mitochondrial function was then assessed using high resolution respirometry after 1.5, 3, 5, 8, 12, 16 and 24 hours of storage. Metabolic marker enzymes for anaerobiosis and mitochondrial mass were also measured in conjunction with non-bicarbonate tissue pH buffering capacity.. Ob/ob and lean mice livers showed severe (>60%) macrovesicular and mild (<30%) microvesicular steatosis on Oil Red O staining, respectively. Ob/ob livers had lower baseline enzymatic complex I activity but similar adenosine triphosphate (ATP) levels compared to lean livers. During cold storage, the respiratory control ratio and complex I-fueled phosphorylation deteriorated approximately twice as fast in ob/ob livers compared to lean livers. Ob/ob livers also demonstrated decreased ATP production capacities at all time-points analyzed compared to lean livers. Ob/ob liver baseline lactate dehydrogenase activities and intrinsic non-bicarbonate buffering capacities were depressed by 60% and 40%, respectively compared to lean livers.. Steatotic livers have impaired baseline aerobic and anaerobic capacities compared to lean livers, and mitochondrial function indices decrease particularly from after 5 hours of cold preservation. These data provide a mechanistic basis for the clinical recommendation of shorter cold storage durations in steatotic donor livers.

Topics: Adenosine; Adenosine Diphosphate; Adenosine Triphosphate; Allopurinol; Anaerobiosis; Animals; Blood Glucose; Body Weight; Buffers; Cell Respiration; Cold Ischemia; Electron Transport; Fasting; Fatty Liver; Glucose Intolerance; Glutathione; Hydrogen-Ion Concentration; Insulin; Insulin Resistance; Liver; Male; Mice, Inbred C57BL; Mice, Obese; Mitochondria, Liver; Organ Preservation Solutions; Oxidative Phosphorylation; Raffinose; Thinness

Thioredoxin-interacting protein (TXNIP), a regulator of cellular oxidative stress, has been associated with activation of NOD-like receptor 3 (NLRP3) inflammasome, inflammation and lipid metabolism, suggesting it has a role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) in diabetes. In this study we investigated whether TXNIP is involved in type 1 diabetes-associated NAFLD and whether antioxidants, quercetin and allopurinol, alleviate NAFLD by targeting TXNIP.. Diabetes was induced in male Sprague-Dawley rats by a single i.p. injection of 55 mg · kg⁻¹ streptozotocin. Quercetin and allopurinol were given p.o. to diabetic rats for 7 weeks. Hepatic function, oxidative stress, inflammation and lipid levels were determined. Rat BRL-3A and human HepG2 cells were exposed to high glucose (30 mM) in the presence and absence of antioxidants, TXNIP siRNA transfection or caspase-1 inhibitor, Ac-YVAD-CMK.. Quercetin and allopurinol significantly inhibited the TXNIP overexpression, activation of NLRP3 inflammasome, down-regulation of PPARα and up-regulation of sterol regulatory element binding protein-1c (SREBP-1c), SREBP-2, fatty acid synthase and liver X receptor α, as well as elevation of ROS and IL-1β in diabetic rat liver. These effects were confirmed in hepatocytes in vitro and it was further shown that TXNIP down-regulation contributed to the suppression of NLRP3 inflammasome activation, inflammation and changes in PPARα and SREBPs.. Inhibition of hepatic TXNIP by quercetin and allopurinol contributes to the reduction in liver inflammation and lipid accumulation under hyperglycaemic conditions. The targeting of hepatic TXNIP by quercetin and allopurinol may have therapeutic implications for prevention of type 1 diabetes-associated NAFLD.

Topics: Allopurinol; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Carrier Proteins; Cell Cycle Proteins; Cell Line; Diabetes Mellitus, Type 1; Dietary Supplements; Fatty Liver; Gene Silencing; Humans; Inflammasomes; Lipid Metabolism; Liver; Male; Molecular Targeted Therapy; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Quercetin; Random Allocation; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species

This study investigated the role of inducible nitric oxide synthase (iNOS) in failure of ethanol-induced fatty liver grafts. Rat livers were explanted 20 h after gavaging with ethanol (5 g/kg) and storing in UW solution for 24h before implantation. Hepatic oil red O staining-positive areas increased from ∼2 to ∼33% after ethanol treatment, indicating steatosis. iNOS expression increased ∼8-fold after transplantation of lean grafts (LG) and 25-fold in fatty grafts (FG). Alanine aminotransferase release, total bilirubin, hepatic necrosis, TUNEL-positive cells, and cleaved caspase-3 were higher in FG than LG. A specific iNOS inhibitor 1400W (5 μM in the cold-storage solution) blunted these alterations by >42% and increased survival of fatty grafts from 25 to 88%. Serum nitrite/nitrate and hepatic nitrotyrosine adducts increased to a greater extent after transplantation of FG than LG, indicating reactive nitrogen species (RNS) overproduction. Phospho-c-Jun and phospho-c-Jun N-terminal kinase-1/2 (JNK1/2) were higher in FG than in LG, indicating more JNK activation in fatty grafts. RNS formation and JNK activation were blunted by 1400W. Mitochondrial polarization and cell death were visualized by intravital multiphoton microscopy of rhodamine 123 and propidium iodide, respectively. After implantation, viable cells with depolarized mitochondria were 3-fold higher in FG than in LG and 1400W decreased mitochondrial depolarization in FG to the levels of LG. Taken together, iNOS is upregulated after transplantation of FG, leading to excessive RNS formation, JNK activation, mitochondrial dysfunction, and severe graft injury. The iNOS inhibitor 1400W could be an effective therapy for primary nonfunction of fatty liver grafts.

Topics: Adenosine; Alanine Transaminase; Allopurinol; Amidines; Animals; Benzylamines; Bilirubin; Caspase 3; Ethanol; Fatty Liver; Female; Gene Expression; Glutathione; Graft Survival; Insulin; JNK Mitogen-Activated Protein Kinases; Liver Transplantation; Membrane Potential, Mitochondrial; Mitochondria; Nitrates; Nitric Oxide Synthase Type II; Nitrites; Organ Preservation Solutions; Raffinose; Rats; Rats, Inbred Lew; Reactive Nitrogen Species; Tyrosine

Excessive dietary fructose intake may have an important role in the current epidemics of fatty liver, obesity and diabetes as its intake parallels the development of these syndromes and because it can induce features of metabolic syndrome. The effects of fructose to induce fatty liver, hypertriglyceridemia and insulin resistance, however, vary dramatically among individuals. The first step in fructose metabolism is mediated by fructokinase (KHK), which phosphorylates fructose to fructose-1-phosphate; intracellular uric acid is also generated as a consequence of the transient ATP depletion that occurs during this reaction. Here we show in human hepatocytes that uric acid up-regulates KHK expression thus leading to the amplification of the lipogenic effects of fructose. Inhibition of uric acid production markedly blocked fructose-induced triglyceride accumulation in hepatocytes in vitro and in vivo. The mechanism whereby uric acid stimulates KHK expression involves the activation of the transcription factor ChREBP, which, in turn, results in the transcriptional activation of KHK by binding to a specific sequence within its promoter. Since subjects sensitive to fructose often develop phenotypes associated with hyperuricemia, uric acid may be an underlying factor in sensitizing hepatocytes to fructose metabolism during the development of fatty liver.

Topics: Allopurinol; Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Enzyme Inhibitors; Fatty Liver; Fructokinases; Fructose; Hep G2 Cells; Hepatocytes; Humans; Liver; Male; Rats; Rats, Sprague-Dawley; Transcriptional Activation; Up-Regulation; Uric Acid

Previous studies demonstrate that Nrf2, a master regulator of antioxidative responses, is essential in mediating induction of many antioxidative enzymes by acute activation of the AhR. However, the role of Nrf2 in protecting against oxidative stress and DNA damage induced by sustained activation of the AhR remains unknown and was investigated herein. Tissue and blood samples were collected from wild-type (WT) and Nrf2-null mice 21 days after administration of a low-toxic dose (10 μg/kg ip) of TCDD. Only Nrf2-null mice lost body weight after TCDD treatment; however, blood levels of ALT were not markedly changed in either genotype, indicating a lack of extensive necrosis. Compared to livers of TCDD-treated WT mice, livers of TCDD-treated Nrf2-null mice had: 1) degenerated hepatocytes, lobular inflammation, marked fat accumulation, and higher mRNA expression of inflammatory and fibrotic genes; 2) depletion of glutathione, elevation in lipid peroxidation and marker of DNA damage; 3) attenuated induction of phase-II enzymes Nqo1, Gsta1/2, and Ugt2b35 mRNAs, but higher induction of cytoprotective Ho-1, Prdx1, Trxr1, Gclc, and Epxh1 mRNAs; 4) higher mRNA expression of Fgf21 and triglyceride-synthesis genes, but down-regulation of bile-acid-synthesis genes and cholesterol-efflux transporters; and 5) trend of induction/activation of c-jun and NF-kB. Additionally, TCDD-treated Nrf2-null mice had impaired adipogenesis in white adipose tissue. In conclusion, Nrf2 protects livers of mice against oxidative stress, DNA damage, and steatohepatitis induced by TCDD-mediated sustained activation of the AhR. The aggravated hepatosteatosis in TCDD-treated Nrf2-null mice is due to increased lipogenesis in liver and impaired lipogenesis in white adipose tissue.

Topics: Animals; Blotting, Western; Caspase 3; Caspase 8; Catalase; DNA Damage; Dose-Response Relationship, Drug; Fatty Liver; Glutathione; Histones; Lipid Peroxidation; Liver; Mice; Mice, Mutant Strains; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Polychlorinated Dibenzodioxins; Polymerase Chain Reaction; Xanthine Oxidase

Here we examine the effect of adding carvedilol (CVD) to University of Wisconsin (UW) solution on the preservation of steatotic and nonsteatotic livers during cold ischemia and after normothermic reperfusion. We used an isolated perfused rat liver model. The following protocols were evaluated. Protocol 1 concerned the effect of CVD after cold ischemia. Steatotic and nonsteatotic livers were preserved for 24 hours in UW solution alone or with CVD. Livers without cold ischemia were used as controls. Transaminases were evaluated in the flushing effluent. Protocol 2 involved the effect of CVD after reperfusion. Both liver types were preserved for 24 hours in UW solution alone or with CVD and then perfused ex vivo for 2 hours at 37 degrees C. Livers flushed and perfused without ischemia were used as controls. Hepatic injury and functionality [transaminases, bile production, and hepatic clearance of sulfobromophthalein (BSP)] were evaluated after reperfusion. In addition, factors potentially involved in hepatic ischemia-reperfusion injury, including oxidative stress (malondialdehyde and superoxide anion levels), mitochondrial damage (glutamate dehydrogenase activity), microcirculatory disorders (flow rate and vascular resistance), and adenosine triphosphate (ATP) depletion, were evaluated after reperfusion. After cold ischemia, steatotic livers preserved in UW solution showed higher transaminase levels than nonsteatotic livers. After reperfusion, steatotic livers preserved in UW solution showed higher transaminase levels and lower bile production and BSP clearance than nonsteatotic livers. Alterations in the perfusion flow rate and vascular resistance, mitochondrial damage, and reduced ATP content were more evident in steatotic livers preserved in UW solution. The addition of CVD to UW solution reduced hepatic injury, obstructed its mechanisms, and improved hepatic functionality in both liver types. We conclude that CVD is a useful additive for UW solution that improves the preservation of steatotic and nonsteatotic livers subjected to prolonged cold ischemia.

Topics: Adenosine; Adenosine Triphosphate; Adenylate Kinase; Adrenergic beta-Antagonists; Allopurinol; Animals; Bile; Carbazoles; Carvedilol; Cold Temperature; Fatty Liver; Glutathione; Insulin; Liver; Liver Function Tests; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Postoperative Complications; Propanolamines; Raffinose; Rats; Rats, Zucker; Reperfusion Injury; Vascular Resistance

This study examined the effects of epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) supplementation to University of Wisconsin solution (UW) in steatotic and nonsteatotic livers during cold storage. Hepatic injury and function were evaluated in livers preserved for 24 hours at 4 degrees C in UW and in UW with EGF and IGF-I (separately or in combination) and then perfused ex vivo for 2 hours at 37 degrees C. AKT was inhibited pharmacologically. In addition, hepatic injury and survival were evaluated in recipients who underwent transplantation with steatotic and nonsteatotic livers preserved for 6 hours in UW and UW with EGF and IGF-I (separately or in combination). The results, based on isolated perfused liver, indicated that the addition of EGF and IGF-I (separately or in combination) to UW reduced hepatic injury and improved function in both liver types. A combination of EGF and IGF-I resulted in hepatic injury and function parameters in both liver types similar to those obtained by EGF and IGF-I separately. EGF increased IGF-I, and both additives up-regulated AKT in both liver types. This was associated with glycogen synthase kinase-3beta (GSK3(beta)) inhibition in nonsteatotic livers and PPAR gamma overexpression in steatotic livers. When AKT was inhibited, the effects of EGF and IGF-I on GSK3(beta), PPAR gamma, hepatic injury and function disappeared. The benefits of EGF and IGF-I as additives in UW solution were also clearly seen in the liver transplantation model, because the presence of EGF and IGF-I (separately or in combination) in UW solution reduced hepatic injury and improved survival in recipients who underwent transplantation with steatotic and nonsteatotic liver grafts. In conclusion, EGF and IGF-I may constitute new additives to UW solution in steatotic and nonsteatotic liver preservation, whereas a combination of both seems unnecessary.

Topics: Adenosine; Allopurinol; Animals; Cell Survival; Cold Ischemia; Disease Models, Animal; Epidermal Growth Factor; Fatty Liver; Glutathione; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Insulin; Insulin-Like Growth Factor I; Liver; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Perfusion; PPAR gamma; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Raffinose; Rats; Rats, Zucker; Recombinant Proteins; Reperfusion Injury; Time Factors

We compared the susceptibility of liver grafts from lean and obese Zucker rats to preservation injury, using two organ-preservation techniques: conventional static preservation (SP) and machine perfusion (MP) preservation. SP: livers preserved by UW solution at 4, 8 or 20 degrees C for 6-h. MP: livers perfused for 6-h with an improved oxygenated Krebs-Henseleit solution (KH) at 4, 8 or 20 degrees C. Reperfusion with KH (2-h) was performed either with the SP or MP preserved livers. Fatty livers tolerate SP poorly at 4, 8 and 20 degrees C as compared with MP at the same temperatures. SP induced a decrease in the ATP/ADP ratio both at 8 and 20 degrees C in obese rats while an increase in energy status was found with MP at 8 and 20 degrees C. Nitrate/nitrite (NOx) concentration was higher and bile flow lower in livers preserved with SP than MP. In lean rats, no differences were observed between MP and SP as regards enzyme release, bile production and NOx levels except for SP at 20 degrees C in which high enzyme release and low bile flow were observed. In lean rats ATP/ADP was higher and NOx was lower with MP at 20 degrees C than with SP at 20 degrees C. To optimize steatotic liver preservation SP should be avoided because it is particularly detrimental as compared with MP.

Topics: Adenosine; Allopurinol; Animals; Cryopreservation; Fatty Liver; Glucose; Glutathione; Insulin; Liver Transplantation; Male; Obesity; Organ Preservation; Organ Preservation Solutions; Perfusion; Raffinose; Rats; Rats, Zucker; Reperfusion Injury; Tromethamine

Human serum albumin binds ligands such as fatty acids and metals in circulation. Oxidative stress can modify albumin and affect ligand binding. This study examines the role of oxidative stress and fatty acids in modulating cobalt binding to albumin in patients with fatty liver. Elevated levels of malondialdehyde and protein carbonyls, indicative of oxidative stress were evident in serum of patients with fatty liver. A significant decrease in albumin-cobalt binding was also observed. Albumin isolated from patient serum also showed an increase in bound fatty acids. In vitro experiments indicated that while oxidant exposure or removal of fatty acids independently decreased cobalt binding to albumin, removal of fatty acids from the protein prior to oxidant exposure did not influence the oxidant effect on albumin-cobalt binding. These results suggest that oxidative stress and fatty acids on albumin can influence albumin-cobalt binding in patients with fatty liver by independent mechanisms.

Topics: Adult; Case-Control Studies; Cobalt; Copper Sulfate; Fatty Acids; Fatty Liver; Female; Humans; Hydrogen Peroxide; Male; Malondialdehyde; Protein Binding; Protein Carbonylation; Serum Albumin; Xanthine; Xanthine Oxidase

This study investigates how the addition of trimetazidine (TMZ) and aminoimidazole-4-carboxamide ribonucleoside (AICAR) to University of Wisconsin (UW) solution protects steatotic livers. Steatotic and nonsteatotic livers were preserved for 24 hours at 4 degrees C in UW and UW with TMZ and AICAR (separately or in combination) and then perfused ex vivo for 2 hours at 37 degrees C. Adenosine monophosphate-activated protein kinase (AMPK) or nitric oxide (NO) synthesis inhibition in livers preserved in UW with TMZ was also investigated. Hepatic injury and function (transaminases, bile production, and sulfobromophthalein clearance) and factors potentially involved in the susceptibility of steatotic livers to ischemia-reperfusion (I/R), including vascular resistance, mitochondrial damage, adenosine triphosphate depletion, and oxidative stress were evaluated. AMPK, NO synthase (NOS), nitrate, and nitrite levels were also determined. The addition of TMZ and AICAR (separately or in combination) to UW reduced hepatic injury, improved functionality, and protected against the mechanisms responsible for the vulnerability of steatotic livers to I/R. Like AICAR, TMZ increased AMPK, constitutive NOS, and nitrates and nitrites, and conversely, AMPK or NO synthesis inhibition abolished the benefits of TMZ. In conclusion, TMZ, by means of AMPK, increased NO, thus protecting steatotic livers against their vulnerability to I/R injury. TMZ and AICAR may constitute new additives to UW solution in steatotic liver preservation, whereas a combination of both seems unnecessary.

Topics: Adenine Nucleotides; Adenosine; Allopurinol; Aminoimidazole Carboxamide; AMP-Activated Protein Kinases; Animals; Enzyme Activators; Fatty Liver; Glutathione; Insulin; Liver; Mitochondria, Liver; Multienzyme Complexes; Nitric Oxide; Nitric Oxide Synthase; Organ Preservation Solutions; Oxidative Stress; Protein Serine-Threonine Kinases; Raffinose; Rats; Rats, Zucker; Reperfusion Injury; Ribonucleotides; Trimetazidine; Vascular Resistance

The aim of this study was to investigate the effects of thymosin alpha(1) (Talpha(1)) in rats having fructose-induced steatosis. Fructose leads to experimental steatosis in the liver by exerting its effect on some components of the oxidant/antioxidant system, and on several cytokines (interleukin-1beta, -2, and -6) in blood.. Twenty-four rats at random were divided into three groups (each group containing eight animals); the control group (C), which received a purified diet; the high-fructose-fed group (F); and the high-fructose-fed and Talpha(1) injected group (F + T). After the experimental period of 10 days, liver lipid peroxidation and antioxidant status, and blood IL-1beta, IL-2, and IL-6 levels were quantified.. In comparison with the C group, the F group had a higher nitric oxide (NO) level, xanthine oxidase (XO) activity, and lipid peroxidation, as indicated by concentrations of thiobarbituric acid reactive substances (TBARS), and lower superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the liver. In the F + T group, these markers were near the values of the control group. In addition, increased IL-1beta and IL-6 levels were kept at near to normal levels with treatment of Talpha(1), but not IL-2 levels. In the F group, the most consistent findings in the histologic sections of liver tissues were the macrovesicular and microvesicular steatosis. Talpha(1) treatment protected the majority of the liver cells, while minimal macrovesicular and microvesicular steatosis was observed in the remaining cells.. These results show that a high-fructose diet in rats leads to hepatic steatosis and a defect in the free radical defense system, and that treatment of Talpha(1) may improve these biochemical and morphologic changes in the fructose-fed rat livers.

Topics: Animals; Antioxidants; Biomarkers; Cytokines; Fatty Liver; Fructose; Glutathione Peroxidase; Lipid Peroxidation; Male; Nitric Oxide; Oxidative Stress; Rats; Rats, Wistar; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Thymalfasin; Thymosin; Xanthine Oxidase

This study examined the effect of preconditioning on steatotic livers for transplantation and attempted to identify the underlying protective mechanisms. Blood flow alterations, neutrophil accumulation, tumor necrosis factor alpha release and lipid peroxidation were observed in nonsteatotic livers after transplantation. Steatotic and nonsteatotic liver grafts were similar in their blood flow, neutrophil accumulation, and TNF release after transplantation. However, in the presence of steatosis, lipid peroxidation and hepatic injury increased. In addition, recipients of steatotic liver grafts were more vulnerable to lung damage associated with transplantation. The conversion of xanthine dehydrogenase to xanthine oxidase and the accumulation of xanthine during cold ischemia was greater in steatotic than in nonsteatotic liver grafts. The results obtained with xanthine oxidase inhibitors indicated that xanthine/xanthine oxidase could be responsible for the increased lipid peroxidation as well as the exacerbated liver and lung damage associated with transplantation of steatotic livers. Preconditioning reduced the xanthine accumulation and percentage of xanthine oxidase seen in steatotic liver grafts during cold ischemia, and conferred protection against liver and lung damage following transplantation. The benefits of preconditioning could be mediated by nitric oxide. These findings suggest that preconditioning could be a relevant new strategy to protect against the inherent risk of steatotic liver failure following transplantation.

Topics: Animals; Apoptosis; Caspases; Cold Temperature; Fatty Liver; Glutathione; In Situ Nick-End Labeling; Ischemic Preconditioning; Liver; Liver Transplantation; Lung; Obesity; Rats; Rats, Sprague-Dawley; Rats, Zucker; Reactive Oxygen Species; Superoxide Dismutase; Thinness; Xanthine Oxidase; Xanthines

The deleterious effect of steatosis on transplanted livers is mainly related to a microcirculation impairment. We investigated the effect of preservation duration on the recovery of isolated perfused rat steatotic livers and tested the effect of pentoxifylline (PTX), known to have a beneficial effect on hepatic microcirculation.. Fatty rat livers were obtained using a diet able to induce an 80% to 100% microvesicular steatosis within 7 days. We studied the effect of the duration of preservation (12 hr, 18 hr, and 24 hr) on fatty and normal isolated perfused rat liver. PTX was added to University of Wisconsin solution during cold storage (30 mM/kg of weight) and at reperfusion (3 mM) (n=5 livers in each group). Lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, bile production, and vascular resistance were evaluated. The liver injury at the end of perfusion was assessed by optical and electron microscopy.. For a 24-hr preservation period, fatty livers demonstrated increased enzymatic release (aspartate aminotransferase: 42+/-16 vs. 17+/-5 IU/L/g of liver, P<0.005; alanine aminotransferase: 32+/-13 vs. 13+/-3 IU/L/g of liver, P<0.005; lactate dehydrogenase: 1,207+/-497 vs. 291+/-195 IU/L/g of liver, P<0.001). Vascular resistance (0.32 vs. 0.15 cm H(2)O/min/mL, P<0.0005) and bile output (67+/-24 vs. 141+/-61 mg/g of liver, P<0.05) were decreased. Peliosis appeared after an 18-hr preservation period for fatty livers compared with a 24-hr preservation period for controls. All these negative effects were suppressed by PTX.. Diffuse microvesicular steatosis became deleterious only after long preservation times (24 hr). PTX prevented this effect.

Topics: Adenosine; Allopurinol; Animals; Fatty Liver; Free Radical Scavengers; Glutathione; Insulin; Ischemia; Liver; Liver Circulation; Liver Function Tests; Male; Organ Preservation; Organ Preservation Solutions; Pentoxifylline; Raffinose; Rats; Rats, Wistar; Time Factors

Fatty livers are more prone to primary nonfunction after transplantation. It is known that cell injury is strongly associated with alterations in the content and composition of membrane lipids. We assumed that plasma membrane (PM) fluidity, which is the most important property of the membrane, differed between fatty and normal livers.. The livers from obese and lean Zucker rats were flushed with cold Ringer's lactate and University of Wisconsin (UW) solution via the portal vein and preserved in cold UW solution for 24 hr. Histological examinations of electron microscopy were performed to investigate of sinusoidal lining cells (SLCs). PMs were isolated using a discontinuous density gradient of Percoll, and the lipid compositions were determined by chromatography.. SLCs of fatty livers were markedly injured compared with control livers even after short preservation time. Moreover, many blebs were observed in the obese rats even after short preservation time. As for PM lipid composition, the cholesterol/phospholipid (PL) ratio of total PM was 0.14+/-0.03 in the obese rats and 0.21+/-0.03 in the lean rats (P<0.05). The relative proportions of polyunsaturated fatty acids among PLs in PM were 35.7+/-1.2% vs. 45.9+/-1.5% (P<0.0001). These results indicated that the fluidity of the PM in the obese rats is decreased after exposure to low temperatures.. Our results suggest that steatotic livers from obese donors are more susceptible to cold preservation injury than livers without steatosis because of the severe deterioration of SLCs, and it is associated with PM fluidity even after short-term cold preservation.

Topics: Adenosine; Allopurinol; Animals; Cell Membrane; Cholesterol; Fatty Acids; Fatty Liver; Glutathione; Insulin; Isotonic Solutions; Liver; Liver Transplantation; Membrane Fluidity; Microscopy, Electron; Obesity; Organ Preservation; Organ Preservation Solutions; Phospholipids; Raffinose; Rats; Rats, Zucker; Ringer's Lactate; Thinness; Time Factors; Triglycerides

Topics: Adenosine; Allopurinol; Animals; Bile; Blood Glucose; Body Weight; Fasting; Fatty Liver; Glutathione; Insulin; Liver Transplantation; Nutritional Status; Organ Preservation Solutions; Organ Size; Raffinose; Rats; Rats, Sprague-Dawley; Time Factors; Tissue Donors; Transplantation, Homologous; Treatment Outcome

Topics: Acetylcysteine; Adenosine; Allopurinol; Animals; Antibodies, Monoclonal; Choline Deficiency; Fatty Liver; Glutathione; Insulin; Intercellular Adhesion Molecule-1; Ischemia; Liver; Male; Methionine; Organ Preservation; Organ Preservation Solutions; Raffinose; Rats; Rats, Wistar; Reperfusion Injury

Topics: Adenosine; Adult; Age Factors; Allopurinol; Aspartate Aminotransferases; Fatty Liver; Glutathione; Humans; Insulin; Liver; Liver Function Tests; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Predictive Value of Tests; Prognosis; Raffinose; Reoperation; Retrospective Studies; Risk Factors; Survival Rate; Treatment Outcome

We studied the morphology of sinusoidal cells on 21 human liver grafts prior to harvesting, at the end of the preservation period in UW solution, and after complete revascularization. The mean cold ischemic period was 11 h 34 min. Immediate follow-up was uneventful in 20 of these cases; 13 showed a mean peak of postoperative transaminases below 1,300 IU/L (group A), and 7 above 1,500 IU/L (group B). In the case of one patient (group C) steatosis was severe (50%) and there was serious postoperative dysfunction (transaminases 18,000 IU/L). Biopsies were perfusion-fixed by the transparenchymal route to ensure satisfactory ultrastructural results. In group A, some sinusoidal endothelial cells presented signs of activation at the end of the preservation period, and even more after revascularization. Kupffer cells also presented signs of activation particularly after reperfusion. Signs of endothelial cell damage with gaps and partial rupture of the plasmic membrane were also observed, particularly after revascularization in areas which contained numerous inflammatory cells adhering to the wall. The sinusoidal pole of hepatocytes was occasionally damaged, with the formation of blebs. In group B, adhesion of inflammatory cells to the sinusoidal wall was increased. Furthermore, in some areas with endothelial cell damage, neutrophils and platelets infiltrated the Disse space, and hepatocytes were increasingly damaged. In the case of patient C, the most obvious signs after reperfusion were hepatocyte drop out and death but there was no evidence of any concomitant sinusoidal cell damage. It would appear that even in cases where immediate follow-up is eventful, endothelial and Kupffer cells show signs of activation. This can be associated with signs of microcirculatory disturbances as was seen in 4 cases in group B. In the only case of severe steatosis that we studied, the essential sign was death of hepatocytes.

Topics: Adenosine; Adult; Alanine Transaminase; Allopurinol; Aspartate Aminotransferases; Endothelium; Fatty Liver; Glutathione; Humans; Insulin; Kupffer Cells; Liver; Liver Transplantation; Microscopy, Electron; Middle Aged; Organ Preservation; Organ Preservation Solutions; Raffinose; Tissue Donors

Recently, we reported that SPC-100270, a sphingosine derivative and inhibitor of protein kinase C (50-90 microM) in mixed micelle assays, reduced reperfusion injury resulting from hypoxia in a low-flow, reflow model of liver perfusion. Here we report that SPC-100270 has similar beneficial effects following liver transplantation in vivo. Rat liver transplantation was performed using nonarterial and rearterial techniques. Livers from syngenic rats were harvested surgically, prepared with vascular cuffs and a splint, and stored for 24 or 48 h in University of Wisconsin (UW) cold storage solution. Just prior to completion of vascular reconstruction, the organ was rinsed with 3 or 10 ml of Ringer's solution, vehicle, or a solution containing SPC-100270 (up to 500 microM). Following implantation surgery, low doses of SPC-100270 were ineffective at reducing both parenchymal and nonparenchymal cell death, yet significant (P < 0.05) reductions were observed with 500 microM. Further, nonparechnymal cell viability was improved nearly four fold by the drug. SPC-100270 (500 microM) tended to increase survival following 48 h cold storage in UW solution, but the improvement was not statistically significant. SPC-100270 also did not diminish carbon-centered free radical formation in transplanted livers from alcohol-treated rats. Collectively, these data support the hypothesis that pretreatment of donor livers with an inhibitor of protein kinase C is effective in vivo at reducing reperfusion injury, particularly to nonparenchymal cells, following orthotopic liver transplantation in the rat.

Topics: Adenosine; Allopurinol; Animals; Cell Survival; Enzyme Inhibitors; Fatty Liver; Female; Glutathione; Graft Survival; Insulin; Liver Transplantation; Organ Preservation Solutions; Protein Kinase C; Raffinose; Rats; Reperfusion Injury; Sphingosine; Transplantation, Isogeneic

Frozen section examination was performed on 385 donor livers before transplantation. Exclusion criteria were applied to the donor livers examined to exclude potentially dysfunctional livers. The exclusion criteria included the following: severe macrovesicular steatosis, ischemic necrosis, prominent chronic portal inflammation, prominent periductular fibrosis, granulomatous inflammation, bridging fibrosis, and malignancy. Twenty-seven of the 385 donor livers examined were excluded before transplantation. The following histologic features were present in the excluded livers: severe steatosis (22), ischemic necrosis (2), portal inflammation (1), and periductular fibrosis (2). Steatosis was present in 51 of the 385 (13.25%) organs examined, including 22 of the donor organs excluded before transplantation. Twenty-nine livers with mild to moderate steatosis were implanted into size and blood type-matched recipients. Indicators of allograft function (prothrombin time and bilirubin) and damage (aspartate aminotransferase and alanine aminotransferase) were measured daily for the first 10 days after transplant. There was no statistically significant difference between the group of nonfat livers and donor livers containing mild steatosis. Statistically significant higher posttransplant serum alanine aminotransferase and prothrombin time levels were present in the patients with livers implanted with mild versus moderate steatosis. The 1-year survival rate for patients receiving fatty versus nonfatty donor livers was not statistically different (Kaplan-Meier, P = 0.592). No significant differences were found in the clinical and laboratory characteristics of donors whose organs were implanted compared with the clinical and laboratory characteristics of donors whose organs were excluded. The primary nonfunction rate after applying the exclusion criteria was 1.4%, which is a significant decrease compared with our primary nonfunction rate of 8.5% before using frozen section examination. Frozen section examination is useful in excluding donor organs which may become dysfunctional after transplantation.

Topics: Adenosine; Adult; Allopurinol; Azo Compounds; Child; Fatty Liver; Female; Fibrosis; Frozen Sections; Glutathione; Hepatitis; Humans; Hypertonic Solutions; Insulin; Ischemia; Liver; Liver Transplantation; Male; Necrosis; Organ Preservation; Organ Preservation Solutions; Raffinose; Staining and Labeling; Survival Rate; Tissue Donors

Topics: Adenosine; Allopurinol; Biopsy; Fatty Liver; Glutathione; Humans; Insulin; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Prognosis; Raffinose; Solutions; Tissue Donors

Weanling male Sprague-Dawley rats were fed ad libitum 15% casein diets with and without 5.0% lysine-HCI, 0.25% adenine sulfate or 0.1% allopurinol for 2 weeks. Addition of lysine alone depressed 2-week growth from 94 to 65 g increased average daily urinary orotic acid excretion from 0.39 to 1.77 mg and increased the percentage of total liver lipids from 3.6 to 11.2. Adenine or allopurinol did not change growth but markedly enhanced lysine-induced orotic aciduria and completely prevented lysine-induced fatty livers. Reports by other show that adenine and allopurinol also prevent fatty livers or rats fed arginine-free diets or excess orotic acid. The authors conclude that lysine-induced orotic aciduria results from arginine deficiency caused by antagonism of arginine function by lysine, and that lysine-induced fatty liver probably results from a lesion identical to that produced by feeding excess orotic acid.

Topics: Adenine; Allopurinol; Animals; Arginine; Diet; Fatty Liver; Lipid Metabolism; Liver; Lysine; Male; Orotic Acid; Rats

Topics: Allopurinol; Animals; Fatty Liver; Liver; Nucleotides; Orotic Acid; Rats

Topics: Acetaldehyde; Animals; Caproates; Ethanol; Fatty Liver; Fructose-Bisphosphate Aldolase; Glyceraldehyde-3-Phosphate Dehydrogenases; Hydroxy Acids; Injections, Intraperitoneal; Keto Acids; Kidney; Liver; Oxidoreductases; Rats; Time Factors; Xanthine Oxidase

Topics: Animals; Colchicine; Fatty Liver; Liver; Male; Oxidoreductases; Rats; Xanthine Oxidase

Topics: Adenine; Aminohydrolases; Animals; DNA; Fatty Liver; Lipid Metabolism; Nucleotides; Orotic Acid; Phospholipids; Rats; RNA; Transferases; Xanthine Oxidase

Topics: Animals; D-Amino-Acid Oxidase; Diabetes Mellitus, Experimental; Fatty Liver; Oxidoreductases; Xanthine Oxidase