Stress-activated protein kinases in the activation of rat hepatic stellate cells in culture

BACKGROUND/AIMS

The signal cascades involved in the activation of hepatic stellate cells (HSC) are largely unknown. Factors initiating activation include tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, endothelin, and oxidative stress. In other cell types some of these have been reported to stimulate p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK). We have therefore investigated the role of these kinases in HSC activation.

METHODS

HSC were isolated from male Wistar rats. Quiescent experiments were performed on day 2 HSC and transformed experiments on day 15 passage 1 HSC. Kinase activities were determined by immunoprecipitation and phosphorylation of specific substrate proteins and alpha-smooth muscle actin (SMA) expression by immunoblotting.

RESULTS

The constitutive activity of p38 MAP kinase was higher in transformed versus quiescent cells. In quiescent cells TNFalpha stimulated p38 MAP kinase and JNK activities 12- and 4-fold respectively and this was halved by 2-mercaptoethanol, an indirect antioxidant. Endothelin-1 activated both kinases in quiescent cells via the endothelin-B receptor, while TGFbeta had no effect. Both 2-mercaptoethanol and a p38 inhibitor (SB202190) inhibited alpha-SMA expression by day 5 cells.

CONCLUSIONS

The activation of p38 MAP kinase and JNK by TNFalpha and endothelin, together with the inhibition of this activation by 2-mercaptoethanol, provides indirect evidence supporting their role in HSC transformation. Direct evidence for a role for p38 MAP kinase is provided by the observations that its constitutive activity is higher in transformed versus quiescent cells and that its inhibitor reduces HSC activation in culture as assessed by alpha-SMA expression.

The role of phosphatidic acid in platelet-derived growth factor-induced proliferation of rat hepatic stellate cells

Platelet-derived growth factor (PDGF) is the most potent mitogen for hepatic stellate cells (HSCs) in vitro. The aim of this study was to investigate the role of the lipid-derived second messenger phosphatidic acid (PA) in mediating this effect and, in particular, to determine its interaction with the extracellular signal-regulated kinase (ERK) cascade. HSCs were isolated from rat livers. PA production was determined by lipid extraction and thin-layer chromatography (TLC) after prelabeling cells with [(3)H]myristate. ERK activity was measured by an in vitro kinase assay after immunoprecipitation. Mitogenic concentrations of PDGF, but not those of the relatively less potent mitogen, transforming growth factor alpha (TGF-alpha), stimulated the sustained production of PA from HSCs. Exogenous PA stimulated HSC proliferation and a sustained increase in ERK activity, and proliferation was completely blocked by the inhibition of ERK activation with PD98059. The stimulation of ERK by PDGF was of a similar magnitude but more sustained than that caused by TGF-alpha. These results suggest that the potent mitogenic effect of PDGF in HSCs may be caused, in part, by the generation of PA and subsequently by a more sustained activation of ERK than occurs with less potent mitogens that do not induce the production of this lipid second messenger.

Inhibition of rat hepatocyte proliferation by transforming growth factor beta and glucagon is associated with inhibition of ERK2 and p70 S6 kinase

Stimulation of hepatocyte proliferation by epidermal growth factor (EGF) and insulin is inhibited by transforming growth factor beta (TGF-beta) and by glucagon. It is also suppressed by inhibitors of various protein kinases, including rapamycin, which blocks activation of p70 S6 kinase (p70(S6k)), PD98059, which inhibits the activation of extracellular-regulated kinase (ERK), and SB 203580, an inhibitor of the p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated whether the inhibition of proliferation by TGF-beta involves these protein kinase cascades. Culture of hepatocytes with TGF-beta for 16 hours decreased the stimulation by EGF of ERK2 and p70(S6k) (by 50% and 35%, respectively), but did not affect the stimulation of either p38 MAPK, c-jun NH2-terminal kinase (JNK), or protein kinase B (PKB). Culture of hepatocytes with glucagon for 16 hours also inhibited the stimulation by EGF of activation of ERK2 and p70(S6k) (by approximately 50%). The inhibitory effects of glucagon were observed when the hormone was added either 10 minutes or 60 minutes before EGF addition, whereas no effects of TGF-beta were observed after 10-minute or 60-minute incubation. These results suggest that the inhibition of hepatocyte proliferation by TGF-beta may be in part mediated by inhibition of ERK2 and p70(S6k), but does not involve PKB, JNK, or p38 MAPK. Unlike glucagon, the effects of TGF-beta are not elicited in response to short-term treatment.

The natural history of histologically proved drug induced liver disease

BACKGROUND

The long term outcome of drug related liver disease is unknown.

AIMS

To study the natural history of histologically proved drug induced hepatotoxicity.

METHODS

110 patients with liver biopsies coded either as drug induced liver disease or hepatitis/cholestasis of unknown aetiology were identified from hospital records 1978-1996. Review of case notes and histology identified 44 patients with definite drug induced hepatotoxicity. Forty surviving patients were invited to attend a follow up clinic. History, examination, full liver screen, and isotope and ultrasound liver scans were repeated in all patients. Repeat liver biopsies were offered to patients with abnormal liver tests.

RESULTS

Presentation at index biopsy was jaundice in 24 patients, abnormal liver tests in 17, and hepatic failure in three. Antibiotics (n=13) and non-steroidal anti-inflammatory drugs (n=11) were the most common drugs implicated. Initial histology showed acute hepatitis in six, chronic hepatitis in 20, and cholestasis in 18. At 1-19 years (median 5 years) follow up, 13/33 (39%) patients had persistent significant abnormalities in their liver blood tests and/or scans. Three of the five repeat liver biopsies performed showed significant abnormalities. Factors predicting persistence or development of chronic liver disease were fibrosis and continued exposure to the drug.

CONCLUSIONS

Drugs should be considered in the differential diagnosis of abnormal liver function and/or histology, as failure to withdraw the offending drug is associated with a high risk of persistent liver damage.

Association of polymorphisms in the cytochrome P450 CYP2C9 with warfarin dose requirement and risk of bleeding complications

BACKGROUND

The cytochrome P450 CYP2C9 is responsible for the metabolism of S-warfarin. Two known allelic variants CYP2C9*2 and CYP2C9*3 differ from the wild type CYP2C9*1 by a single aminoacid substitution in each case. The allelic variants are associated with impaired hydroxylation of S-warfarin in in-vitro expression systems. We have studied the effect of CYP2C9 polymorphism on the in-vivo warfarin dose requirement.

METHODS

Patients with a daily warfarin dose requirement of 1.5 mg or less (low-dose group, n=36), randomly selected patients with a wide range of dose requirements from an anticoagulant clinic in north-east England (clinic control group, n=52), and 100 healthy controls from the community in the same region were studied. Genotyping for the CYP2C9*2 and CYP2C9*3 alleles was done by PCR analysis. Case notes were reviewed to assess the difficulties encountered during the induction of warfarin therapy and bleeding complications in the low-dose and clinic control groups.

FINDINGS

The odds ratio for individuals with a low warfarin dose requirement having one or more CYP2C9 variant alleles compared with the normal population was 6.21 (95% CI 2.48-15.6). Patients in the low-dose group were more likely to have difficulties at the time of induction of warfarin therapy (5.97 [2.26-15.82]) and have increased risk of major bleeding complications (rate ratio 3.68 [1.43-9.50]) when compared with randomly selected clinic controls.

INTERPRETATION

We have shown that there is a strong association between CYP2C9 variant alleles and low warfarin dose requirement. CYP2C9 genotyping may identify a subgroup of patients who have difficulty at induction of warfarin therapy and are potentially at a higher risk of bleeding complications.

Tumour necrosis factor-alpha promoter polymorphisms in primary biliary cirrhosis

BACKGROUND/AIMS

The incidence of primary biliary cirrhosis (PBC) is increased in the close relatives of patients, suggesting that genetic factors play a role in disease susceptibility. Decreased in vitro production of tumour necrosis factor (TNF)-alpha has been reported in PBC patients, suggesting a potential aetiological role for this cytokine. The aim of this study was to examine two biallelic polymorphisms in the promoter region of the TNF-alpha gene, which may play a role in the control of TNF-alpha secretion, as candidate susceptibility loci in PBC.

METHODS

The polymorphisms at positions -238 and -308 in the TNF-alpha promoter region were analysed by polymerase chain reaction in 168 unrelated PBC patients and 145 local unrelated, geographically matched normal individuals. All PBC subjects were also genotyped for HLA DR8, a previously identified susceptibility locus in PBC.

RESULTS

The -308 TNF1/TNF1 genotype was seen in a similar proportion of PBC patients (66%) and controls (60%). However, this genotype was found significantly more frequently in the 95 PBC patients with more advanced disease (histological stage III/IV) (77%) than in either controls (p<0.01, OR = 2.2 [1.2-4.0]) or the PBC patients with earlier disease (38/73 (52%), p = 0.001 OR 3.1 [1.6-5.9]). Linkage between TNF -308 and HLA DR8 was not seen. No association was found between PBC and the biallelic -238 TNF-alpha polymorphism, either in the whole PBC population or the histological Stage III/IV subgroup.

CONCLUSIONS

Our study provides no evidence for involvement of the TNF-alpha -308 or -238 promoter polymorphisms in genetic predisposition to PBC. However, the significantly increased frequency of the -308 TNF1/TNF1 genotype seen in 95 patients with more advanced disease raises the possibility that this allele may be linked to disease progression rather than susceptibility. The finding of different allele frequencies in PBC patients in different disease subgroups emphasises the importance of clinical phenotype/casemix in the design of disease association studies.

Detection and characterization of novel polymorphisms in the CYP2E1 gene

To investigate whether interindividual variation in CYP2E1 levels can be explained by genetic polymorphism, we analysed DNA samples from 40 healthy individuals by single-strand conformational polymorphism analysis for polymorphisms in the CYP2E1 coding sequence and promoter region. DNA sequencing of samples showing mobility shifts on single-strand conformational polymorphism detected polymorphisms at positions -316 (A to G), -297 (T to A), -35 (G to T), 1107 (G to C; intron 1), 4804 (G to A Val179Ile; exon 4) and 10157 (C to T; exon 8). All individuals positive for either A(-316)G, G(-35)T, G(4804)A or the previously described RsaI polymorphism at -1019 were also positive for T(-297)A, which had the highest allele frequency of the observed polymorphisms (0.20). A(-316)G, G(-35)T and G(4804)A were detected at allele frequencies of 0.022, 0.052 and 0.013, respectively. The functional significance of the upstream polymorphisms was examined by preparing constructs of positions -549 to +3 of CYP2E1 containing the observed combinations of the polymorphisms fused to luciferase reporter genes and transfecting HepG2 cells. For the G(-35)T/T(-297)A construct, a 1.8-fold increase in luciferase activity compared with the wild-type sequence (P = 0.06) and 2.5-fold compared with T(-297)A only (P = 0.025) was observed. No significant difference in activity was observed between the other constructs. The significance of the predicted Val179Ile base change from G(4804)A was determined by expression of the wild-type and mutated full length cDNAs in lymphoblastoid cells. No significant difference in kinetic constants for chlorzoxazone hydroxylation between mutant and wild-type was observed. In summary, this study demonstrated six novel CYP2E1 polymorphisms, including three upstream of the promoter, but with the possible exception of G(-35)T, none appeared to be of functional significance.

Diagnosis and interpretation of steatosis and steatohepatitis

Steatosis--accumulation of triacylglycerol in hepatocytes--is a common finding in liver biopsy specimens. The commonest form is macrovesicular change, which occurs in response to a wide range of insults. In the absence of other features, the pathologist cannot ascertain the likely cause on morphological features alone but can give an indication of the severity of steatosis. Close clinicopathological correlation is required to establish the cause. In most instances, macrovesicular steatosis is at least potentially reversible. Although it may be thought of as a benign condition, it may be associated with the development of necroinflammation and fibrosis--so-called steatohepatitis. The classic example of this is alcoholic hepatitis, but there is increasing awareness of steatohepatitis occurring in nonalcoholics: NASH. Distinction between alcoholic hepatitis and NASH on purely histological grounds may be impossible; careful clinicopathological discussion is mandatory. Microvesicular steatosis is generally a more severe disease than the macrovesicular form and is seen in a variety of conditions in which there is either an inherited or an acquired defect in beta-oxidation of fatty acids; the former includes mitochondrial cytopathies and disorders of ureagenesis, and the latter includes acute fatty liver of pregnancy and Reye's syndrome. This review describes the morphological features of steatosis and steatohepatitis, considers their pathogenesis, and outlines the clinical significance of the different patterns of injury.

Intravenous bisphosphonate prevents symptomatic osteoporotic vertebral collapse in patients after liver transplantation

Osteoporosis is common in patients with chronic cholestatic liver disease, and atraumatic spinal fracture is a recognized complication after orthotopic liver transplantation. Bisphosphonates are potent inhibitors of osteoclast bone resorption and have been successfully used to treat postmenopausal osteoporosis. We examined whether preoperative bone mineral density can predict the risk of fracture after orthotopic liver transplantation and whether intravenous bisphosphonate can prevent fractures in high-risk patients. Beginning in February 1993, standard bone mineral density measurements of the lumbar spine were performed as part of routine pretransplantation assessment. On the basis of a preliminary analysis from January 1995, patients with a lumbar spine bone mineral density of <0.84 g/cm2, or <84% of the predicted value (age/sex), were treated with intravenous bisphosphonate (pamidronate disodium) every 3 months before and for 9 months after liver transplantation. Bone mineral density measurements were available in 90 of 136 consecutive first transplants performed in our unit from February 1993 to September 1996. Before the use of pamidronate, 7 patients sustained symptomatic vertebral fractures. Their mean spine bone mineral density was lower than in the 38 patients with no clinical evidence of fracture (81.8% +/- 12.3% v 94.2% +/- 10.2%; P = .006). Since the introduction of pamidronate, no symptomatic vertebral fractures have occurred. Of 29 surviving patients with bone mineral density <0.84 g/cm2 before transplantation, 38% who did not receive treatment with pamidronate suffered spontaneous fracture, whereas 0 of 13 who received treatment suffered such a complication. A low lumbar spine bone mineral density is associated with a high risk of symptomatic vertebral fracture after liver transplantation. These results suggest that this risk is considerably reduced by the administration of intravenous bisphosphonate before and after transplantation.

Heterozygotes for HFE mutations have no increased risk of advanced alcoholic liver disease

BACKGROUND

Iron overload is common in the livers of alcoholics and may play a role in disease pathogenesis. An MHC like gene, HFE, has recently been identified that is mutated in most patients with hereditary haemochromatosis (C282Y in 90% and H63D in 45% of the remainder).

AIM

To examine the hypothesis that these mutations determine hepatic iron status in alcoholics and play a role in pre-disposition to advanced alcoholic liver disease.

METHODS

The HFE gene was genotyped in 257 patients with alcoholic liver disease and 117 locally matched healthy volunteers. In addition, iron staining was scored (0-4) on biopsy specimens from fibrotic/cirrhotic patients with and without HFE mutations matched for age and sex.

RESULTS

Some 15.7% of fibrotic/cirrhotic patients were C282Y heterozygotes compared with 13.7% of controls (p = 0.77). One control and three patients were C282Y homozygotes. Of chromosomes without the C282Y mutation, 68/442 (15.4%) of patients' chromosomes carried the H63D mutation compared with 36/216 (16.6%) of control chromosomes (p = 0.91). Significant (> grade 1) hepatocyte iron staining was seen in 6/23 C282Y heterozygotes and 4/26 H63D heterozygotes compared with 4/23 controls.

CONCLUSIONS

Possession of a single copy of either of the two HFE mutations influences neither liver iron content nor the risk of fibrotic disease in alcoholics.

The RsaI polymorphism of CYP2E1 and susceptibility to alcoholic liver disease in Caucasians: effect on age of presentation and dependence on alcohol dehydrogenase genotype

Twin studies in Caucasians suggest that susceptibility to alcoholic liver disease is, in part, genetically determined. Because most of the deleterious effects of alcohol are caused by its metabolism, attention has focused upon genes encoding ethanol metabolizing enzymes. Caucasians are polymorphic at only two of these gene loci--cytochrome P450 2E1 (CYP2E1) and alcohol dehydrogenase 3 (ADH3). We examined the frequency of the RsaI polymorphism of CYP2E1 and ADH3 genotype in 264 patients with alcoholic liver disease and 121 local control individuals. There was a non-significant excess of the rare c2 CYP2E1 allele in patients with advanced liver disease compared with control individuals/patients with steatosis only (0.029 versus 0.017/0.00). However, patients with the c2 allele presented at a younger age compared with those with the wild type c1 allele only (42.3 +/- 1.6 years versus 49.0 +/- 0.6 years; P = 0.001) with at least as advanced histology (93% cirrhotic versus 74%). Male patients had a higher frequency of the ADH3*2/*2 genotype (which encodes the less active gamma2 subunit) than control individuals [odds ratio (OR) 2.04 (1.11-3.76)], however, ADH3 genotype did not differ with histological stage or with age of presentation. Patients with advanced disease possessing the c2 allele had a significantly higher frequency of the ADH3*2/*2 genotype compared with c1 homozygotes [OR 3.71 (1.24-11.09)]. This study demonstrates that, although rare in Caucasians, possession of the mutant c2 allele of CYP2E1 increases the risk of alcoholic liver disease at a given level of cumulative alcohol consumption. This risk appears to be particularly manifest in individuals carrying the ADH3*2 allele, presumably reflecting increased metabolism of ethanol by CYP2E1. In the absence of the c2 allele, ADH3 genotype does not influence the risk of advanced alcoholic liver disease but, in males at least, may influence the risk of alcoholism.

The inheritance of alcoholic liver disease

Available evidence supports the concept that alcoholic liver disease (ALD) is a multifactorial disease with a heritable component. A number of polymorphic genes with small and additive effects will thus encode susceptibilty to this 'polygenic' disease. Molecular genetic studies of ALD are in their infancy, and methods available for the genetic dissection of complex traits are discussed. Some candidate genes have been identified, and studies have been undertaken to test for association between specific alleles and ALD susceptibility. There is evidence to support a role for alleles of two genes encoding enzymes involved in the oxidative metabolism of alcohol (acetaldehyde dehydrogenase2*2 and cytochrome P4502E1 c2 allele) in susceptibility to ALD. More recently, attention has focused on cytokines, and there are now data showing association of specific alleles of both tumour necrosis factor alpha and interleukin-10 with predisposition to ALD. These candidate genes need to be subjected to rigorous evaluation in different populations. Such research should help to define more precisely the molecular mechanisms underlying the development of ALD in a sub-population (< 20%) of alcoholics, thereby improving the hepatologist's ability to develop rational treatments.

Heterozygosity for hereditary hemochromatosis is associated with more fibrosis in chronic hepatitis C

Hepatic iron has been associated with more aggressive liver disease in chronic viral hepatitis. We evaluated whether the recently described C282Y mutation of the hemochromatosis gene, designated HFE (responsible for at least 83% of hereditary hemochromatosis), was associated with more advanced liver disease in chronic hepatitis C. One hundred thirty-seven patients with biopsy-proven chronic hepatitis C were studied and liver biopsies scored for necroinflammation (grade 0-18) and fibrosis (stage 0-6). Genomic DNA was amplified by polymerase chain reaction and the C282Y mutation identified by restriction with RsaI and electrophoretic separation of restriction fragments. Ten (7.3%) patients had the C282Y mutation. No C282Y homozygous patients were identified. Age, sex distribution, and estimated weekly alcohol consumption were not significantly different between those with and without the mutation. Serum ferritin was higher in the heterozygotes (mean, 339 microg/L) compared with homozygous wild types (153 microg/L; P = .0005). In the majority of patients, liver iron was graded 0 out of 4, but hepatocyte iron staining was more commonly present in heterozygotes compared with homozygous normals (30% compared with 4% [P = .02]). Liver disease was more advanced in those with the mutant allele (mean fibrosis stage: 3.6, compared with wild type: 1.5 [P = .01]). Cirrhosis was found more often in those with the mutation (40%) compared with those without (8.7%) (P = .01; odds ratio: 7.6 [1.9-31.2]). There was no significant difference in inflammation scores between heterozygotes and wild type (mean, 5.4 compared with 4.1). Hepatitis C virus (HCV)-RNA titers were measured by branched DNA assay (HCV RNA 2.0-Chiron), and there was no difference between heterozygous and homozygous normal patients. Thus, despite relatively minor increases in iron stores, individuals who are heterozygous for hemochromatosis appear to develop more fibrosis in chronic hepatitis C. Venesection may be useful therapy in this subgroup.

No evidence for involvement of the interleukin-10 -592 promoter polymorphism in genetic susceptibility to primary biliary cirrhosis

BACKGROUND/AIMS

Primary biliary cirrhosis is a chronic cholestatic liver disease with an autoimmune aetiology. Family studies, which have shown a significantly increased incidence of primary biliary cirrhosis in the close relatives of patients, suggest that genetic factors play a significant role in determining disease susceptibility. Several studies have previously identified loci which appear to play a role in determining this susceptibility, including the MHC class II allele HLA DR8, and the class III encoded C4A null allele (C4AQ0). Here, we have studied another candidate susceptibility locus in primary biliary cirrhosis, an apparently functional biallelic polymorphism at position -592 in the promoter region of the gene encoding the immuno-modulatory cytokine interleukin-10. Interleukin-10 plays an important role in the functional control, in vivo, of autoreactive Th-1 type CD4+ T-cells, with experimental manipulation of interleukin-10 leading to significant modulation of disease development in animal models of autoimmunity.

METHODS

Interleukin-10 -592 genotypes were studied by polymerase chain reaction in 171 well-characterised, histologically-staged, primary biliary cirrhosis patients and 141 locally matched controls.

RESULTS

Of 171 primary biliary cirrhosis patients, 99 were homozygous for the commoner allele (C/C), 68/171 (40%) were heterozygotes (A/C), whilst 4/171 (2%) were homozygous for the rarer allele (A/A). These genotype frequencies were not significantly different from those seen in controls (p=0.49, odds ratio 1.2 [0.8-1.91).

CONCLUSIONS

These findings, in the first study of IL-10 as a candidate locus in a human autoimmune disease, suggest that IL-10 -592 is not a susceptibility locus in primary biliary cirrhosis.

Tumour necrosis factor-alpha gene promoter polymorphism and decreased insulin resistance

Insulin resistance is a feature of non-diabetic relatives of non-insulin-dependent diabetic (NIDDM) families. Tumour necrosis factor-alpha (TNF alpha) expression is linked with insulin resistance, and is under strong genetic control. We examined the relationship between insulin resistance and two polymorphisms of the TNF alpha promoter region (positions -238 and -308). Non-diabetic relatives (n = 123) of NIDDM families and control subjects (n = 126) with no family history of diabetes were studied. Insulin resistance was determined by homeostasis model assessment (HOMA) and short insulin tolerance test (ITT), and genotyping was by restriction digest. The -238 polymorphism (TNFA-A allele) was carried by 14 relatives and 11 control subjects, and all were heterozygotes. To examine the relationship between the -238 polymorphism and insulin resistance independent of potentially confounding factors, the relatives with the TNFA-A allele were individually pair-matched for age, sex, waist-hip ratio, body mass index, and glucose tolerance with relatives homozygous for the wild-type allele. Relatives with the TNFA-A allele had decreased insulin resistance (HOMA index: 2.0, 3.6 +/- 2.1 [means +/- SD of differences], p = 0.03), and this was true for comparable pair-matched control subjects (HOMA index: 1.1, 1.9 +/- 0.8, p = 0.01). Combining relative (n = 7) and control (n = 4) pairs that had undergone an ITT, subjects with the TNFA-A allele had an increased K(ITT) (3.8, 3.0 +/- 1.0%/min, p = 0.04) similarly indicating decreased insulin resistance. There was no significant relationship between the -308 polymorphism and insulin resistance. We conclude that the TNFA-A allele is associated with decreased insulin resistance as assessed by two independent methods, and may protect against the future development of NIDDM in susceptible individuals.

Transjugular intrahepatic portosystemic shunt: a limited role in refractory ascites

OBJECTIVE

To evaluate the role of the transjugular intrahepatic portosystemic shunt (TIPS) in the management of patients with refractory ascites.

DESIGN

A retrospective study of 25 consecutive patients for whom refractory ascites was the primary indication for TIPS insertion.

SETTING

Regional liver unit at Freeman Hospital, Newcastle upon Tyne, UK.

PARTICIPANTS AND INTERVENTIONS

Twelve male and 13 female patients with a mean age of 58 years and mean Child-Pugh score of 10, treated with TIPS for refractory ascites between July 1992 and September 1995.

MAIN OUTCOME MEASURES

Effect of TIPS on mortality, ascites and hospital admission rate.

RESULTS

TIPS was successfully placed in all patients with a 59% mean reduction in portosystemic pressure gradient. Response rate was 68%, 48% and 33% at 1, 3 and 12 months, respectively. Mortality was 48% at 3 months and 67% at 12 months, being higher in those patients older than 60, those with renal impairment and those with higher Child-Pugh score. Amongst nine patients surviving long term (> 12 months) the mean time spent in hospital in the 3 months before TIPS was 35 days and in the year following TIPS 30 days. Patients who died (16 in total) spent a mean of 19 days in hospital before TIPS, 10 never leaving hospital, and 6 who were discharged spent a mean of 19 days post procedure in hospital (mean survival 84 days).

CONCLUSION

TIPS has a limited role in the management of patients with refractory ascites. It is not an appropriate treatment where patients are older than 60, have renal impairment (creatinine > 200 mumol/l) or have a Child-Pugh score greater than 10.

Association of a tumor necrosis factor promoter polymorphism with susceptibility to alcoholic steatohepatitis

Twin concordance studies suggest that genetic factors play a role in determining why only a minority of heavy drinkers develop hepatitis and cirrhosis. Tumor necrosis factor alpha (TNF-alpha) has emerged as the "final common pathway" in the pathogenesis of alcohol-related hepatic necro-inflammation. We have examined the frequency of the two recently described polymorphisms of the TNF-alpha promoter in 150 patients with biopsy-proven alcoholic liver disease and 145 healthy volunteers. There was a significant excess of the rare allele (TNFA-A; G(-238) --> A) at position -238 in patients with steatohepatitis compared with controls or patients without this lesion. This is consistent with previous suggestions that the TNFA-A allele, which falls within a putative Y regulation box of the TNF-alpha promoter, is associated with increased TNF-alpha expression. No differences were observed for the polymorphism at position -308.

Transforming growth factor beta increases the activity of phosphatidate phosphohydrolase-1 in rat hepatocytes

Phosphatidic acid (PA) is a potent second messenger arising from growth factor-induced stimulation of phospholipase D which hydrolyses phosphatidylcholine. PA is hydrolysed to diacylglycerol by PA phosphohydrolase (PAP) which exists in two forms: PAP-1 and PAP-2. In rat hepatocyte cultures, overnight (20h) incubation with transforming growth factor (TGF) beta (1 ng/ml) increased PAP-1 activity two-fold. This effect was concentration and time dependent and was greatest at low cell density. The TGFbeta effect on PAP-1 was additive to stimulation induced by dexamethasone but not by glucagon and it reversed the inhibition by insulin. Epidermal growth factor had no effect on PAP-1 activity. None of the above hormones or growth factors affected the subcellular distribution of PAP-1. Stimulation of PAP-1 by TGFbeta may be involved in mediating some of its biological effects.

Hepatic stellate cell activation occurs in the absence of hepatitis in alcoholic liver disease and correlates with the severity of steatosis

BACKGROUND/AIMS

There is now overwhelming evidence that hepatic stellate cells are the principal cells involved in hepatic fibrogenesis. In several different forms of liver injury it has been demonstrated that they proliferate and undergo phenotypic transformation (activation) into matrix-producing, myofibroblast-like cells in response to necroinflammation, mediated in part, by Kupffer cell-derived factors. In alcoholic liver disease, however, the observation that fibrosis can occur in the absence of alcoholic hepatitis has cast doubt on necroinflammation being an absolute pre-requisite for alcohol-related hepatic stellate cells proliferation/activation and subsequent fibrogenesis.

METHODS

Evidence for hepatic stellate cells activation has been sought in liver biopsies from 38 well-documented alcoholic patients with no evidence of alcoholic hepatitis or cirrhosis and eight normal controls. Activated hepatic stellate cells were identified immunohistochemically using a specific monoclonal antibody to detect cytoplasmic alpha smooth muscle actin (alpha-SMA), which is not present in quiescent cells. Kupffer cells were detected with the monoclonal antibody KP1 and collagen was stained using Sirius red. Immunoreactive cells and the amount of fibrosis were quantified, using a Kontron Vidas Image Analyser. Steatosis was graded from 0 (none-few hepatocytes containing fat) to 3 (> 2/3 hepatocyte containing fat).

RESULTS

Biopsies from alcoholic patients contained significantly greater numbers of activated hepatic stellate cells (alpha-SMA+ve) than control biopsies (average cell counts: 84 +/- 11/mm2 versus 23 +/- 5/mm2, p < 0.0001). There was no correlation between numbers of activated hepatic stellate cells and either numbers of Kupffer cells or amount of fibrosis. There was, however, a significant correlation between hepatic stellate cells activation and steatosis (grade 0, 15 +/- 7 cells/unit area (n = 4), grade 1, 56 +/- 16 (n = 13), grade 2, 85 +/- 20 (n = 9), grade 3, 137 +/- 19 (n = 12); p = 0.002, ANOVA).

CONCLUSIONS

These results suggest that neither necroinflammation nor an increase in Kupffer cells is an absolute prerequisite for hepatic stellate cells proliferation/activation and subsequent fibrogenesis in alcoholic liver disease. The correlation between alcohol-induced hepatic stellate cells activation and severity of steatosis is likely to reflect that both are attributable in part to the metabolic consequences of ethanol metabolism, namely increased concentrations of acetaldehyde and lipid peroxidation.