Protective Effects of Kakkalide From Flos Puerariae on Ethanol-Induced Lethality and Hepatic Injury Are Dependent on Its Biotransformation by Human Intestinal Microflora

When kakkalide, which was isolated from Flos Puerariae, was incubated with human fecal bacteria, kakkalide was metabolized to irisolidone via kakkalidone. When kakkalide (250 mg/kg) was orally administered to rats, irisolidone, but not kakkalide, was detected in the blood. The mortality associated with ethanol treatment was slightly reduced when the mice were intraperitoneally treated with kakkalide. Intraperitoneally administered kakkalide and kakkalidone did not reduce alcohol toxicity. However, orally administered kakkalide and intraperitoneally administered irisolidone significantly reduced the mortality. Orally administered kakkalide and intraperitoneally injected irisolidone greatly reduced serum alanine aminotransferase and aspartate aminotransferase activities in ethanol-intoxified mice. Orally administered kakkalide and intraperitoneally administered irisolidone significantly lowered the level of blood ethanol. The results indicate that kakkalide is a prodrug of irisolidone in protecting against ethanol-induced lethality and hepatic injury.

Copper metabolic defects and liver disease: environmental aspects

Copper (Cu) is an essential trace element for many biological processes. Cu homeostasis is generally well maintained by inbuilt controls in intestinal absorption, biliary excretion and intrahepatic storage. Copper deficiency disorders are rare. Acute Cu toxicity occurs occasionally in accidental poisoning with Cu sulfate. Chronic Cu toxicity in the form of liver cirrhosis and damage to other organs is seen classically in Wilson's Disease (genetic abnormality of Cu metabolism) and in the presumed environmental disorder Indian Childhood Cirrhosis (ICC). The clinical, epidemiological and treatment aspects of ICC are described. The evidence linking ICC to environmental Cu is (i) greatly increased hepatic Cu; (ii) early introduction of Cu contaminated milk boiled or stored in brass vessels; (iii) dramatic decline in ICC throughout the country coincident with change in feeding vessels; and (iv) continued long-term remission in d-penicillamine-treated patients after withdrawal of the drug. The nature and role of a second factor in the causation of ICC remains unclear, although a genetic predisposition is strongly suspected. Scattered reports of an ICC-like illness from the West (Idiopathic Cu Toxicosis, Endemic Tyrolean Infantile Cirrhosis), suggest that different mechanisms (environmental, genetic or both) can lead to the same end stage liver disease-'ecogenetic' disorders.

Protective role of Kupffer cells in acetaminophen-induced hepatic injury in mice

Hepatic injury induced by various toxic agents, including acetaminophen (APAP), has been attributed, in part, to the production of proinflammatory cytokines and other mediators by resident Kupffer cells within the liver. However, recent evidence from our laboratory has demonstrated that hepato-protective factors, such as interleukin (IL)-10 and cyclooxygenase-derived mediators, are also upregulated in response to hepatic damage to help protect against exacerbated injury, and Kupffer cells have been suggested to be a source of these modulatory factors. In other models, Kupffer cells also serve important regulatory functions in pathophysiological states of the liver. Therefore, we reevaluated the role of Kupffer cells in a murine model of APAP-induced liver injury using liposome-entrapped clodronate (liposome/clodronate) as an effective Kupffer cell-depleting agent. We show that in contrast to pretreatment of mice with a widely used macrophage inhibitor, gadolinium chloride, which did not deplete Kupffer cells but moderately protected against APAP-induced hepatotoxicity as reported previously, the intravenous injection of liposome/clodronate caused nearly complete elimination of Kupffer cells and significantly increased susceptibility to APAP-induced liver injury as compared with mice pretreated with empty liposomes. This increased susceptibility was apparently unrelated to the metabolism of APAP since liposome/clodronate pretreatment did not alter APAP-protein adduct levels. Instead, Kupffer cell depletion by liposome/clodronate led to significant decreases in the levels of hepatic mRNA expression of several hepato-regulatory cytokines and mediators, including IL-6, IL-10, IL-18 binding protein and complement 1q, suggesting that Kupffer cells are a significant source for production of these mediators in this model. Our findings indicate that, in addition to their protoxicant activities, Kupffer cells can also have an important protective function in the liver through the production of a variety of modulatory factors which may counteract inflammatory responses and/or stimulate liver regeneration.

Protective effect of rutin on paracetamol- and CCl4-induced hepatotoxicity in rodents

Rutin, a well-known flavonoid was investigated for its possible protective effect against paracetamol- and CCl(4)-induced hepatic damage. Paracetamol produced 100% mortality at the dose of 1 g/kg in mice while pre-treatment of animals with rutin (20 mg/kg) reduced the death rate to 40%. Oral administration of a sub-lethal dose of paracetamol (640 mg/kg) produced liver damage in rats as manifested by the rise in serum level of transaminases (AST and ALT). Pre-treatment of rats with rutin (20 mg/kg) prevented the paracetamol-induced rise in serum enzymes. The hepatotoxic dose of CCl(4) (1.5 ml/kg; orally) also raised the serum AST and ALT levels. The same dose of rutin (20 mg/kg) was able to prevent the CCl(4)-induced rise in serum enzymes. Rutin also prevented the CCl(4)-induced prolongation in pentobarbital sleeping time confirming its hepatoprotectivity. These results indicate that rutin possesses hepatoprotective activity and the presence of this compound in Artemisia scoparia may explain the folkloric use of the plant in liver damage.

[Hepatic injury induced by acute lung injury in aging rats]

OBJECTIVE

To investigate the induction of hepatic function damage by acute lung injury (ALI) in aging rats and the effect of Ginkgo Biloba extract (GBE) on this process.

METHODS

Thirty male Wistar rats were used to produce the aging animal model. Aging rats were randomly divided into three groups: the control group, the lipopolysaccharide (LPS, intravenous injection) group, and the GBE + LPS group (GBE given 7 days before experiment, once a day, via the esophagus). Samples from the blood, the lung and the liver were collected 2 and 6 h after LPS or saline administration.

RESULTS

ALI was induced by intravenous injection of LPS in aging rats. Compared with the aging control, the total bilirubin content and the glutamic pyruvic transaminase (GPT) activity in serum did not change at 2 h after LPS administration. But at 6 h, they were increased, respectively from (10.9 +/- 0.6) mg/L and (26 +/- 3) U in the control group to (30.1 +/- 2.1) mg/L and (88 +/- 12) U in the LPS group (P < 0.001). MDA content increased in the blood and the lung tissue at 2 has compared to the control group, from (15.9 +/- 1.8) micro mol/L and (18.8 +/- 2.1) nmol/mg protein to (22.1 +/- 1.9) micro mol/L and (28.8 +/- 3.1) nmol/mg protein (all P < 0.001), respectively. SOD activity in the lung tissue was decreased significantly, from (25.5 +/- 2.6) mU/L and (36.1 +/- 2.4) U/mg protein to (20.6 +/- 1.9) mU/L and (32.0 +/- 2.7) U/mg protein, respectively (P < 0.05, P < 0.001). The GSH-P(X) activity and the Na(+)-K(+)-ATPase activity in the lung tissue at 2 hours after LPS administration were decreased markedly, from (28.2 +/- 2.8) U/mg protein and (4.9 +/- 0.5) micromol Pi x mg(-1) protein x h(-1). to (21.1 +/- 2.7) U/mg protein and (3.1 +/- 0.3) micromol Pi x mg(-1) protein x h(-1). These changes lasted 6 h after LPS administration. These parameters did not change significantly in the hepatic tissue at 2 h after LPS administration. But after 6 h, MDA content was increased from (7.9 +/- 0.9) nmol/mg protein to (10.9 +/- 0.7) nmol/mg protein; while the GSH-P(X) and the Na(+)-K(+)-ATPase activities were decreased markedly, from (59.0 +/- 3.9) U/mg protein and (0.87 +/- 0.04) micromol Pi x mg(-1) protein x h(-1) to (49.2 +/- 3.0) U/mg protein and (0.77 +/- 0.04) micromol Pi x mg(-1) protein x h(-1) (P < 0.001, P < 0.01). There was no obvious change in the SOD activity. All the changes were significantly attenuated in the GBE + LPS group (P < 0.05, P < 0.01).

CONCLUSION

Hepatic function damage could be induced by ALI in aging rats. GBE showed a protective effect on ALI and hepatic function damage in this animal model.

Effects of melatonin and lactulose on the liver and kidneys in rats with obstructive jaundice

The negative effects of obstructive jaundice (OJ) on the liver and kidneys cause high morbidity and mortality. In this study, the effects of melatonin (M) and lactulose (L) on the liver and kidneys were investigated by inducing OJ in 30 rats in five groups (n = 6): controls, sham, M, L, and M + L. In the treatment group, after the rats' biliary canals were tied and cut, 10 mg/kg M IM and 2 ml/day L p.o. was administered for 7 days. The histopathologic findings in the liver and kidneys, tissue malonyl dialdehyde (MDA) levels, and serum biochemistry were evaluated. In the M group, pathological histologic findings were less marked than in the other groups; investigation of kidney cross-sections revealed no significant differences among groups. In the jaundiced rats liver MDA levels were significantly higher compared to the control group ( P < 0.001), but no such difference was observed in kidney MDA levels ( P > 0.05). L did not cause any significant changes in tissue MDA levels. There were no differences among groups with regard to serum levels of liver enzymes and bilirubin. Serum urea was significantly less in the group that received L ( P < 0.001), but the groups showed no significant differences with respect to creatinine values ( P > 0.05). The increase in serum total cholesterol was significantly less in the M + L group than in the other groups ( P < 0.001). We conclude that in the rats in which obstructive jaundice was induced, M administration reduced liver and kidney injury, but L and M + L did not lead to significant improvement.

Pyrogallol-induced hepatotoxicity in rats: a model to evaluate antioxidant hepatoprotective agents

Various hepatic disorders and hepatotoxic agents are associated with increased free radical generation. In the present study, the free radical generator pyrogallol (100 mg/kg i.p.) caused significant hepatic damage. The serum enzymes asparatate aminotransaminase (AST) and alanine aminotransaminase (ALT) increased to 357 +/- 30.7 IU/I and 147.8 +/- 28.4 IU/I, respectively in the pyrogallol-treated group compared with 208.4 +/- 4.1 IU/I and 84.5 +/- 19.5 IU/I, respectively in the control rats. Compared with control rats, the liver tissue in the pyrogallol-treated group showed an increased level of malondialdehyde (MDA) as well as glutathione (GSH). The infiltration of white blood cells into the liver tissue, as seen histologically, further substantiated liver damage. Pretreatment with a standard hepatoprotective drug (silymarin, 100 mg/kg i.p.) afforded significant protection against pyrogallol hepatotoxicity, as evidenced by amelioration of the raised serum markers of hepatic function, markers of oxidative stress and normal liver histology. Thus, pyrogallol-induced hepatotoxicity could be used as an appropriate model to evaluate hepatoprotective agents that have an antioxidant property.

Adenosine preconditioning attenuates hepatic reperfusion injury in the rat by preventing the down-regulation of endothelial nitric oxide synthase

BACKGROUND

Previous work has suggested that in the liver, adenosine preconditioning is mediated by nitric oxide. Whether the endothelial isoform of nitric oxide synthase plays a part in this mechanism has however not yet been investigated.

METHODS

Wistar rats were used (6 in each group)--Groups: (1) sham, (2) ischemia-reperfusion, (3) adenosine + ischemia-reperfusion, (4) endothelial isoform inhibitor + adenosine + ischemia-reperfusion.

RESULTS

Using immunohistochemistry, this study has revealed a decrease in the expression of endothelial nitric oxide synthase following hepatic ischemia-reperfusion. This was prevented by adenosine pre-treatment. When an inhibitor of endothelial nitric oxide synthase was administered prior to adenosine pre-treatment, pre-conditioning did not occur despite normal expression of endothelial nitric oxide synthase.

CONCLUSIONS

These findings suggest that adenosine attenuates hepatic injury by preventing the downregulation of endothelial nitric oxide synthase that occurs during ischemia-reperfusion.

Ursodeoxycholic acid for the prevention of hepatic complications in allogeneic stem cell transplantation

The role of ursodeoxycholic acid (UDCA) in the prevention of hepatic complications after allogeneic stem cell transplantation was studied in a prospective randomized open-label multicenter trial. A total of 242 patients were allocated to receive (n = 123) or not to receive (n = 119) UDCA in the dose of 12 mg/kg/d orally from the day preceding the conditioning until day 90 after transplantation. In the UDCA-treated group a significantly smaller proportion of patients developed a serum bilirubin level exceeding 50 microM (18 of 123 versus 31 of 119, P =.04), and similarly a smaller proportion of patients exceeded the alanine aminotransferase level of 100 U/L. There was no difference in the incidence of veno-occlusive disease of the liver. Compared to the control group, in the UDCA-treated group there was a nonsignificant trend toward a lower overall incidence of acute graft-versus-host disease (GVHD) and a significantly lower incidence of grade III to IV acute GVHD (5 of 123 versus 17 of 119, P =.01), stage II to IV liver and intestinal GVHD, and stage III to IV skin GVHD. There was no difference in the incidence of chronic GVHD or in the relapse rate. Among the patients given UDCA, the survival at 1 year was significantly better, 71% versus 55% (P =.02), and the nonrelapse mortality rate was lower, 19% versus 34% (P =.01), than in the control group. There were significantly more deaths in GVHD in the control group. In conclusion, UDCA administration reduced hepatic problems and severe acute GVHD and improved survival. These results suggest a role for UDCA in the prevention of transplant-related complications in allogeneic transplantation.

Protective effect of carnosol on CCl(4)-induced acute liver damage in rats

BACKGROUND

We recently reported that (Lamiaceae) may alleviate CCl(4)-induced acute hepatotoxicity in rats, possibly blocking the formation of free radicals generated during CCl(4) metabolism. Carnosol, one of the main constituents of Rosmarinus, has been shown to have antioxidant and scavenging activities. Therefore, it is plausible to expect that carnosol may mediate some of the effects of Rosmarinus on oxidative stress consequences induced by CCl(4) in the liver.

DESIGN

We evaluated the effectiveness of carnosol to normalize biochemical and histological parameters of CCl(4)-induced acute liver injury.

METHODS

Male Sprague Dawley rats (n = 5) injured by CCl(4) (oral dose 4 g/kg of body weight) were treated with a single intraperitoneal dose (5 mg/kg) of carnosol. Twenty-four hours later, the rats were anaesthetized deeply to obtain the liver and blood, and biochemical and histological parameters of liver injury were evaluated.

RESULTS

Carnosol normalized bilirubin plasma levels, reduced malondialdehyde (MDA) content in the liver by 69%, reduced alanine aminotransferase (ALT) activity in plasma by 50%, and partially prevented the fall of liver glycogen content and distortion of the liver parenchyma.

CONCLUSIONS

Carnosol prevents acute liver damage, possibly by improving the structural integrity of the hepatocytes. To achieve this, carnosol could scavenge free radicals induced by CCl(4), consequently avoiding the propagation of lipid peroxides. It is suggested that at least some of the beneficial properties of Rosmarinus officinalis are due to carnosol.

Prevention of taurolithocholate-induced hepatic bile canalicular distortions by HPLC-characterized extracts of artichoke (Cynara scolymus) leaves

The effects of water-soluble extracts of artichoke (Cynara scolymus L.) leaves on taurolithocholate-induced cholestatic bile canalicular membrane distortions were studied in primary cultured rat hepatocytes using electron microscopy. Artichoke extracts at concentrations between 0.08 and 0.5 mg/ml were able to prevent the formation of bizarre canalicular membrane transformations in a dose-dependent manner when added simultaneously with the bile acid. However, prevention also occurred when the hepatocytes were preincubated with the extracts, indicating that absorption of the bile acid to components of the extracts was not involved. These results demonstrate that artichoke leaf extracts exert a potent anticholestatic action at least in the case of taurolithocholate. This effect may contribute to the overall hepatoprotective influence of this herbal formulation.

Ocimum sanctum aqueous leaf extract provides protection against mercury induced toxicity in Swiss albino mice

HgCl2 (5.0 mg/kg body weight) induced toxicity led to significant elevation of lipid peroxidation (LPO) level but decline in the glutathione content in liver of Swiss albino mice. In serum of HgCl2 treated mice there was significant elevation in serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) activities but significant decline in the alkaline phosphatase activity. Animals treated with O. sanctum extract (10 mg/kg body weight, po) before and after mercury intoxication showed a significant decrease in LPO level, SGOT and SGPT activities and increase in serum alkaline phosphatase activity and glutathione (GSH) content. Ocimum treatment alone did not alter SGOT, SGPT and alkaline phosphatase activities but significantly enhanced reduced glutathione. The results suggest that oral administration of Ocimum extract provides protection against HgCl2 induced toxicity in Swiss albino mice.

Tauroursodeoxycholic acid (TUDCA) in the prevention of total parenteral nutrition-associated liver disease

OBJECTIVE

To determine whether tauroursodeoxycholic acid (TUDCA) would prevent or ameliorate the liver injury in neonates treated with total parenteral nutrition (TPN).

STUDY DESIGN

Eligible infants were enrolled after surgery when serum direct bilirubin (DB) was <2 mg/dL. TUDCA (30 mg/kg/day) was given enterally to 22 subjects. A concurrent untreated/placebo group was evaluated for comparison (n = 30). Blood chemistries including alanine aminotransferase (ALT), alkaline phosphatase (AP), conjugated bilirubin (CB), and bile acids (BA) were obtained weekly.

RESULTS

There was no difference in peak serum CB, ALT, AP, or BA levels between the TUDCA-treated and control infants. When stratified for birth weight (<1500 g and >1500 g), no differences in peak CB, ALT, AP, or BA were noted. Serum CB levels were similar between TUDCA-treated and control infants after 14, 40, 60, 70, and 120 days of TPN.

CONCLUSION

TUDCA appears ineffective in preventing the development or treatment of TPN-associated cholestasis in neonates. Erratic biliary enrichment and prolonged inability to initiate treatment may compromise the utility of enterically administered TUDCA for TPN-treated infants.

Antioxidant and antihepatotoxic activities of Phellinus rimosus (Berk) Pilat

The antioxidant and antihepatotoxic activities of a wood inhabiting macrofungus, Phellinus rimosus were studied. The superoxide anion scavenging, Fe(2+)-ascorbate induced lipid peroxidation inhibiting, hydroxyl radical scavenging and nitric oxide scavenging activities of the ethyl acetate extract were determined. The results indicated that ethyl acetate extract of P. rimosus exhibited significant in vitro antioxidant activity. The ethyl acetate extract of P. rimosus also showed potent antihepatotoxic activity against carbontetrachloride-induced acute toxicity in rat liver. The amelioration of liver toxicity by the ethyl acetate extract was evident from its significant effect on the levels of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and serum alkaline phosphatase (ALP). The results suggest that hepatoprotective effect of P. rimosus is possibly related to the free radical scavenging activity.

Targeting of liposomal flavonoid to liver in combating hepatocellular oxidative damage

The efficacy of mannosylated liposome formulations with Quercetin (QC, a flavonoid antioxidant isolated from indigenous origin) has been tested in vivo against carbon tetrachloride(CCl(4))-induced liver oxidative damage in rats. Single subcutaneous injection of CCl(4) (40% v/v in olive oil; 1 ml/kg) induces the generation of toxic oxygen radicals and results in hepatocellular damage. The increased serum enzyme levels (glutamate pyruvate transaminase, alkaline phosphatase) and hepatocellular conjugated diene levels by CCl(4) induction were significantly lowered due to pretreatment with mannosylated liposomal QC (MLQ) (0.5 ml liposomal suspension containing 0.27 mg QC), whereas the same amount of free QC was found to be ineffective. In addition, the effectiveness of MLQ on CCl(4)-induced acute liver damage also was evaluated by tissue histopathological examination. Damage produced by CCl(4) in liver reverted to normal with pretreatment of MLQ.

Intramuscular administration of very high dose of alpha-tocopherol protects liver from severe ischemia/reperfusion injury

The effect of intramuscular administration of high (30 mg/kg body weight for 3 days) or very high (300 mg/kg body weight for 3 days) doses of a-tocopherol to Wistar rats subjected to total severe warm hepatic ischemia and reperfusion was investigated. After a 60-minute period of total hepatic ischemia and 120 minutes of reperfusion, animals were killed, and liver samples were taken for determination of malondialdehyde (MDA) and histological examinations. Blood samples were also taken for assay of serum a-tocopherol, alanine transaminase (ALT), aspartate transaminase (AST), and lactic dehydrogenase (LDH). Additional animals were followed for a 7-day survival rate determination. Results showed that ischemia and reperfusion decreased the survival rate to 10%, whereas the levels of AST, ALT, and LDH in serum were increased compared with levels in animals that were sham operated. The MDA concentrations in liver were also increased, from 1.142 to 1.567 nmoles/g, whereas the levels of a-tocopherol in serum were decreased from 10.20 to 1.80 mmol/L. Pretreatment with a-tocopherol increased the viability to 50% and 70%, for the high and very high doses, respectively, and decreased the levels of AST, ALT, and LDH in serum. It also decreased the MDA concentrations in liver to 0.975 and 0.774 nmoles/g for the high and very high doses of a-tocopherol, respectively, whereas it increased the level of a-tocopherol in serum to 11.25 and 13.02 mmol/L for the high and very high doses, respectively. Histological examinations showed protection of the liver parenchyma in the animals treated with a-tocopherol.

Differential long-term subcellular responses in heart and liver to adriamycin stress. Exogenous L-carnitine cardiac and hepatic protection

In order to evaluate the heart and liver responses after adriamycin (ADR) toxic aggression, with and without exogenous L-carnitine (CAR) protection, female Sprague-Dawley rats, body weight 40-60 g, were randomized into four groups: CON, ADR, CAR and CAR-ADR. ADR was injected i.v. at a dose of 15-18 mg/kg body wt (0.1 ml). CAR was administered i.v. at a dose of 20 mg (0.1 ml) before each subdose of ADR, and then orally at 180 mg/kg body wt daily for 12 weeks. Long-term cardiac and hepatic subcellular damage were determined by transmission electron microscopic analysis of ultrathin sections. The ADR-induced long-term cardiac subcellular pathology included loss, disruption and disassembly of myofibrils, and mitochondrial swelling and condensation. On the other hand, the ADR-induced subcellular hepatic alterations consisted of polymorphic mitochondria, cytoplasmic vacuolization and accumulation of lipid droplets. Apparently, cardiac tissue was more affected by ADR toxic aggression than hepatic tissue. However, these alterations were of less severity in protected groups, in both heart and liver, suggesting CAR as a possible hepatoprotector agent against ADR toxicity. Because of the liver-L-carnitine-heart relationship, studying ADR-hepatotoxicity could be helpful in the further understanding of severe ADR-cardiotoxicity.

Hepatitis A, hepatitis B, and combination hepatitis vaccines for immunoprophylaxis: an update

Since the publication of the last extensive review of hepatitis vaccines, use of inactivated hepatitis A vaccines has been extended to high-risk regions of the United States and specific patient groups, such as those with chronic liver disease, and use of the recombinant hepatitis B vaccines has been recommended for older adolescents. A combination hepatitis A and B vaccine, recently approved for licensure by the US Food and Drug Administration, should increase convenience and compliance, reduce the costs of vaccination, and provide prolonged and dual protection for those at risk for hepatitis. Although commercially available vaccines for hepatitis C, D, and E remain a distant goal, advances in vaccine and adjuvant technology, including immunization with DNA-based vaccines, hold promise for the future.

Acetaminophen hepatotoxicity: the first 35 years

The acetaminophen nomogram including its uses and limitations is discussed as well as the development of the N-acetylcysteine protocol. While it has taken many years to elucidate the genetic variability and true multiplicity of the cytochrome P450 "mixed function oxidase system" many publications early on looked at the enzyme system as a single entity. Numerous articles indicated that barbiturates, anticonvulsants, and others could induce "P450" and add to the toxicity of acetaminophen. It rapidly became apparent that just because "P450" was induced when measured as a whole, not all other substrates would have changed metabolic activity. The role of diet and ethanol induction and inhibition on CYP2E1, the enzyme of greatest interest for acetaminophen is multifaceted. The lack of enhancement of acetaminophen toxicity by phenytoin and in fact, the potential for reduction of toxicity with that agent is a good example of the evolution of our knowledge. Further complicating our understanding is the introduction of misleading terms such as "therapeutic misadventure" and other expressions of molecular intent. A critical understanding of the literature makes it clear that therapeutic doses of acetaminophen either alone or in the presence of inducers do not produce toxicity. While the community of clinical toxicologists is small, it needs to be more aggressive in making sure that physicians from other specialties and non-clinical toxicology colleagues understand the significance and implications of this science.

Transforming growth factor alpha protects against Fas-mediated liver apoptosis in mice

The Fas/Fas ligand interaction plays a crucial role in various liver diseases, and administration of agonistic anti-Fas antibody to mice causes massive hepatic apoptosis and fulminant hepatic failure. Several growth factors have recently been found to function in preventing apoptosis. In this study, we demonstrated that overexpression of transforming growth factor alpha (TGFalpha) has a dramatic protective effect on Fas-mediated hepatic apoptosis at the biochemical and histological levels. Moreover, 85.7% (six out of seven) of TGFalpha transgenic mice survived the lethal liver damage, whereas all wild-type mice died. Expression of Bcl-xL, an anti-apoptotic protein, was greatly increased in the transgenic mice. Taken together, our findings suggest that TGFalpha protects against Fas-mediated liver apoptosis in vivo and up-regulation of Bcl-xL may participate in protective effect of TGFalpha.

n-3 Polyunsaturated fatty acid-enriched diet does not protect from liver injury but attenuates mortality rate in a rat model of systemic endotoxemia

OBJECTIVE

We investigated the potential of dietary fish oil containing n-3 polyunsaturated fatty acids to attenuate hepatic injury and mortality rate of rats in response to systemic endotoxemia.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

University laboratory.

SUBJECTS

A total of 43 male Sprague Dawley rats.

INTERVENTIONS

Rats were fed either fish oil supplement or regular standard lab chow. After 8 wks of feeding, each diet group was subjected to a single exposure of lipopolysaccharide (Escherichia coli, 10 mg/kg intravenously) or saline. Hepatic microvascular response and liver injury were assessed by in vivo analysis of Kupffer cell phagocytic activity, leukocyte-endothelial cell interaction, nutritive sinusoidal perfusion failure, and parenchymal cell apoptosis (intravital fluorescence epi-illumination technique) as well as bile flow, serum liver enzyme activities, and tissue histomorphology.

MEASUREMENTS AND MAIN RESULTS

In animals fed a standard diet, livers at 16 hrs after lipopolysaccharide-exposure exhibited depressed Kupffer cell phagocytic activity, enhanced hepatic microvascular leukocyte activation, leukocytic tissue infiltration, sinusoidal perfusion failure, and parenchymal cell apoptosis. Hepatic microvascular injury was further accompanied by reduced bile flow and enhanced liver enzyme release. The fish oil enriched diet did not significantly change the multiple features of endotoxemia-associated liver injury; however, it maintained arterial blood pressure, systemic leukocyte count, and acid base balance and showed a tendency toward improved survival on lipopolysaccharide exposure with a 16 hr-survival rate of 80% (p =.06 vs. survival rate of 40% in animals fed a regular diet). Moreover, slightly increased serum concentrations of interleukin-10 coincided with enhanced concentrations of interleukin-6 in fish oil fed endotoxemic animals. Healthy, non-lipopolysaccharide-exposed, fish oil fed animals did not differ from those fed with the regular diet, except for dampened Kupffer cell phagocytic activity.

CONCLUSIONS

Fish oil feeding does not protect from local endotoxemia-induced hepatic microvascular dysfunction. However, dietary modulation of inflammatory mediator response by macrophages, constituting an appropriate immune response, could add to the survival advantage seen in fish oil-fed animals on exposure to lipopolysaccharide.