Features and Outcomes of 899 Patients With Drug-Induced Liver Injury: The DILIN Prospective Study

BACKGROUND & AIMS

The Drug-Induced Liver Injury Network is conducting a prospective study of patients with DILI in the United States. We present characteristics and subgroup analyses from the first 1257 patients enrolled in the study.

METHODS

In an observational longitudinal study, we began collecting data on eligible individuals with suspected DILI in 2004, following them for 6 months or longer. Subjects were evaluated systematically for other etiologies, causes, and severity of DILI.

RESULTS

Among 1257 enrolled subjects with suspected DILI, the causality was assessed in 1091 patients, and 899 were considered to have definite, highly likely, or probable DILI. Ten percent of patients died or underwent liver transplantation, and 17% had chronic liver injury. In the 89 patients (10%) with pre-existing liver disease, DILI appeared to be more severe than in those without (difference not statistically significant; P = .09) and mortality was significantly higher (16% vs 5.2%; P < .001). Azithromycin was the implicated agent in a higher proportion of patients with pre-existing liver disease compared with those without liver disease (6.7% vs 1.5%; P = .006). Forty-one cases with latency ≤7 days were caused predominantly by antimicrobial agents (71%). Two most common causes for 60 DILI cases with latency >365 days were nitrofurantoin (25%) or minocycline (17%). There were no differences in outcomes of patients with short vs long latency of DILI. Compared with individuals younger than 65 years, individuals 65 years or older (n = 149) were more likely to have cholestatic injury, although mortality and rate of liver transplantation did not differ. Nine patients (1%) had concomitant severe skin reactions; implicated agents were lamotrigine, azithromycin, carbamazepine, moxifloxacin, cephalexin, diclofenac, and nitrofurantoin. Four of these patients died.

CONCLUSIONS

Mortality from DILI is significantly higher in individuals with pre-existing liver disease or concomitant severe skin reactions compared with patients without. Additional studies are needed to confirm the association between azithromycin and increased DILI in patients with chronic liver disease. Older age and short or long latencies are not associated with DILI mortality.

Comparative analysis of portal hepatic infiltrating leucocytes in acute drug-induced liver injury, idiopathic autoimmune and viral hepatitis

Drug-induced liver injury (DILI) is often caused by innate and adaptive host immune responses. Characterization of inflammatory infiltrates in the liver may improve understanding of the underlying pathogenesis of DILI. This study aimed to enumerate and characterize leucocytes infiltrating liver tissue from subjects with acute DILI (n = 32) versus non-DILI causes of acute liver injury (n = 25). Immunostains for CD11b/CD4 (Kupffer and T helper cells), CD3/CD20 (T and B cells) and CD8/CD56 [T cytotoxic and natural killer (NK) cells] were evaluated in biopsies from subjects with acute DILI, either immunoallergic (IAD) or autoimmune (AID) and idiopathic autoimmune (AIH) and viral hepatitis (VH) and correlated with clinical and pathological features. All biopsies showed numerous CD8(+) T cells and macrophages. DILI cases had significantly fewer B lymphocytes than AIH and VH and significantly fewer NK cells than VH. Prominent plasma cells were unusual in IAD (three of 10 cases), but were associated strongly with AIH (eight of nine) and also observed in most with AID (six of nine). They were also found in five of 10 cases with VH. Liver biopsies from subjects with DILI were characterized by low counts of mature B cells and NK cells in portal triads in contrast to VH. NK cells were found only in cases of VH, whereas AIH and VH both showed higher counts of B cells than DILI. Plasma cells were associated most strongly with AIH and less so with AID, but were uncommon in IAD.

Serum proteomic profiling in patients with drug-induced liver injury

BACKGROUND

Idiosyncratic drug-induced liver injury (DILI) is a complex disorder that is difficult to predict, diagnose and treat.

AIM

To describe the global serum proteome of patients with DILI and controls.

METHODS

A label-free, mass spectrometry-based quantitative proteomic approach was used to explore protein expression in serum samples from 74 DILI patients (collected within 14 days of DILI onset) and 40 controls. A longitudinal analysis was conducted in a subset of 21 DILI patients with available 6-month follow-up serum samples.

RESULTS

Comparison of DILI patients based on pattern, severity and causality assessment of liver injury revealed many differentially expressed priority 1 proteins among groups. Expression of fumarylacetoacetase was correlated with alanine aminotransferase (ALT; r = 0.237; P = 0.047), aspartate aminotransferase (AST; r = 0.389; P = 0.001) and alkaline phosphatase (r = -0.240; P = 0.043), and this was the only protein with significant differential expression when comparing patients with hepatocellular vs. cholestatic or mixed injury. In the longitudinal analysis, expression of 53 priority 1 proteins changed significantly from onset of DILI to 6-month follow-up, and nearly all proteins returned to expression levels comparable to control subjects. Ninety-two serum priority 1 proteins with significant differential expression were identified when comparing the DILI and control groups. Pattern analysis revealed proteins that are components of inflammation, immune system activation and several hepatotoxicity-specific pathways. Apolipoprotein E expression had the greatest power to differentiate DILI patients from controls (89% correct classification; AUROC = 0.97).

CONCLUSION

This proteomic analysis identified differentially expressed proteins that are components of pathways previously implicated in the pathogenesis of idiosyncratic drug-induced liver injury.

A naturally occurring human/hepatitis E recombinant virus predominates in serum but not in faeces of a chronic hepatitis E patient and has a growth advantage in cell culture

Hepatitis E virus is the aetiological agent of acute hepatitis E, a self-limiting disease prevalent in developing countries. Molecular analysis of viral genomic RNA from a chronically infected patient confirmed the recent discovery that chronic infection correlated with extensive diversification of the virus quasispecies: the hypervariable region of some virus genomes in this USA patient contained large continuous deletions and a minor proportion of genomes in faeces and serum had acquired a mammalian sequence that encoded 39 aa of S19 ribosomal protein fused to the virus non-structural protein. Genomes with this insert were selected during virus passage in cultured cells to become the predominant species, suggesting that the inserted sequence promoted virus growth. The results demonstrated that hepatitis E virus can mutate dramatically during a prolonged infection and suggests it may be important to prevent or cure chronic infections before new variants with unpredictable properties arise.

Association of filamin A and vimentin with hepatitis C virus proteins in infected human hepatocytes

Chronic hepatitis C (CHC) infection caused by hepatitis C virus (HCV) is a major cause of liver disease and remains a major therapeutic challenge. A variety of host proteins interact with HCV proteins. The definitive role of cytoskeletal (CS) proteins in HCV infection remains to be determined. In this study, our aim was to determine the expression profile of differentially regulated and expressed selected CS proteins and their association with HCV proteins in infected hepatocytes as possible therapeutic targets. Using proteomics, qRT-PCR, Western blot and immunofluorescence techniques, we revealed that filamin A (fila) and vimentin (vim) were prominently increased proteins in HCV-expressing human hepatoma cells compared with parental cells and in liver biopsies from patients with CHC vs controls. HCV nonstructural (NS) 3 and NS5A proteins were associated with fila, while core protein partially with fila and vim. Immunoprecipitation showed interactions among fila and NS3 and NS5A proteins. Cells treated with interferon-α showed a dose- and time-dependent decrease in CS and HCV proteins. NS proteins clustered at the perinuclear region following cytochalasin b treatment, whereas disperse cytoplasmic and perinuclear distribution was observed in the no-treatment group. This study demonstrates and signifies that changes occur in the expression of CS proteins in HCV-infected hepatocytes and, for the first time, shows the up-regulation and interaction of fila with HCV proteins. Association between CS and HCV proteins may have implications in future design of CS protein-targeted therapy for the treatment for HCV infection.

Effect of bovine serum albumin on mitochondrial respiration in the brain and liver of mice and rats

We studied the effect of BSA (in the isolation medium) on the oxidation rate of succinate, glutamate, pyruvate, and α-ketoglutarate by mitochondria of the brain and liver from C57Bl/6g mice and Taconic Sprague Dawley rats. BSA had no effect on liver mitochondrial respiration, but increased oxidation of substrates (particularly of succinate) in brain mitochondria. Therefore, the major effect of BSA on brain mitochondria is manifested in activation of SDH. The improvement of mitochondrial properties in the brain after treatment with BSA is associated with antioxidant activity of this agent. Our results confirm the hypothesis that inhibition of SDH in brain mitochondria is not the artifact. This process serves as a mechanism protecting neurons from free oxygen radicals during succinate oxidation.

Induction of heme oxygenase-1 by phenylarsine oxide. Studies in cultured primary liver cells

Heme oxygenase-1, the major inducible isoform of heme oxygenase (HO), can be induced by heme and numerous other physical and chemical factors, many of which cause cellular 'stress'. This has led to the realization that HO-1 is a major highly conserved stress or heat shock protein. Recent work has implicated activation of mitogen-activated protein kinases and other kinases in the mechanism of induction of HO-1, and suggested that signal transduction pathways through tyrosine kinases are involved in induction of HO-1 gene expression by stress inducers. We hypothesized that phenylarsine oxide (PAO), an inhibitor of protein tyrosine phosphatases (PTPs), might up-regulate the HO-1 gene. Here, we show that a remarkably brief (1-15 min) exposure of normal hepatocytes to low concentrations (0.5-3 microM) of PAO produces a marked increase in mRNA and protein of HO-1. This increase is comparable to the level obtained by addition of heme (20 microM), and occurs without producing changes in cellular glutathione levels or stabilization of HO-1 message. Preincubation of cells with inhibitors of protein synthesis decreased the ability of PAO to increase levels of HO-1 mRNA, suggesting that the inductive effect requires de novo protein synthesis. Addition of thiol donors abrogated the PAO-mediated induction of HO-1 in a dose dependent fashion. Addition of genistein, a tyrosine kinase inhibitor, blunted the induction produced by both PAO and heme. After brief incubations with PAO or heme, cell extracts showed comparable increases in levels of protein tyrosine phosphorylation in general, and specifically in ZAP70 kinase. Our results are consistent with the proposition that induction of HO-1 by PAO involves inhibition of specific PTP(s), and that the mechanisms of induction of HO-1 by PAO and by heme may share some common pathways.

Extrahepatic manifestations of infection with hepatitis C virus

Chronic hepatitis C is associated with, and may trigger or exacerbate, an extraordinary variety of extrahepatic manifestations. Most of these manifestations affect the skin, the most frequent and important of which are the leukocytoclastic vasculitis of MC type II and PCT. The former is an example of an autoimmune disorder triggered by HCV infection, whereas PCT is a skin disease caused by hepatic overproduction of uro- and 7-carboxyl porphyrins caused by increased oxidative stress in hepatocytes. Currently available effective therapies of CHC (IFN, ribavirin) may also trigger or exacerbate extrahepatic manifestations, especially including autoimmune thyroiditis, skin rashes, and hemolytic anemia.

Urea and hypertonicity increase expression of heme oxygenase-1 in murine renal medullary cells

Epithelial cells derived from the mammalian kidney medulla are responsive to urea at the levels of signal transduction and gene regulation. Hybridization of RNA harvested from control- and urea-treated murine inner medullary collecting duct (mIMCD3) cells with a cDNA expression array encoding stress-responsive genes suggested that heme oxygenase (HO)-1 mRNA was upregulated by urea. RNase protection assay confirmed this upregulation; hypertonicity also increased HO-1 mRNA expression but neither hypertonic NaCl nor urea were effective in the nonrenal 3T3 cell line. The effect on HO-1 expression appeared to be transcriptionally mediated on the basis of mRNA half-life studies and reporter gene analyses using the promoters of both human and chicken HO-1. Although urea signaling resembles that of heavy metal signaling in other contexts, the effect of urea on HO-1 transcription was independent of the cadmium response element in this promoter. Urea-inducible HO-1 expression was sensitive to antioxidants but not to scavengers of nitric oxide. Urea also upregulated HO-1 protein expression and pharmacological inhibition of HO-1 action with zinc protoporphyrin-sensitized mIMCD3 cells to the adverse effects of hypertonicity but not to urea. Coupled with the prior observation of others that HO-1 expression increases along the renal corticomedullary gradient, these data suggest that HO-1 expression may comprise an element of the adaptive response to hypertonicity and/or urea in renal epithelial cells.

Induction of heme oxygenase-1 by phenylarsine oxide. Studies in cultured primary liver cells

Heme oxygenase-1, the major inducible isoform of heme oxygenase (HO), can be induced by heme and numerous other physical and chemical factors, many of which cause cellular 'stress'. This has led to the realization that HO-1 is a major highly conserved stress or heat shock protein. Recent work has implicated activation of mitogen-activated protein kinases and other kinases in the mechanism of induction of HO-1, and suggested that signal transduction pathways through tyrosine kinases are involved in induction of HO-1 gene expression by stress inducers. We hypothesized that phenylarsine oxide (PAO), an inhibitor of protein tyrosine phosphatases (PTPs), might up-regulate the HO-1 gene. Here, we show that a remarkably brief (1-15 min) exposure of normal hepatocytes to low concentrations (0.5-3 microM) of PAO produces a marked increase in mRNA and protein of HO-1. This increase is comparable to the level obtained by addition of heme (20 microM), and occurs without producing changes in cellular glutathione levels or stabilization of HO-1 message. Preincubation of cells with inhibitors of protein synthesis decreased the ability of PAO to increase levels of HO-1 mRNA, suggesting that the inductive effect requires de novo protein synthesis. Addition of thiol donors abrogated the PAO-mediated induction of HO-1 in a dose dependent fashion. Addition of genistein, a tyrosine kinase inhibitor, blunted the induction produced by both PAO and heme. After brief incubations with PAO or heme, cell extracts showed comparable increases in levels of protein tyrosine phosphorylation in general, and specifically in ZAP70 kinase. Our results are consistent with the proposition that induction of HO-1 by PAO involves inhibition of specific PTP(s), and that the mechanisms of induction of HO-1 by PAO and by heme may share some common pathways.

Comparative effects of different doses of ribavirin plus interferon-alpha2b for therapy of chronic hepatitis C: results of a controlled, randomized trial

Compared to either drug alone, therapy with the combination of ribavirin and interferon-alpha leads to improved rates of response in patients with chronic hepatitis C. Side effects often mandate downward dose adjustment or cessation of therapy, and the optimal dose of ribavirin has not been established. The aim of this study was to learn whether 600 mg ribavirin per day would prove as efficacious as 1,000-1,200 mg/day when combined with interferon (3 million units thrice weekly) for therapy of patients previously treated with standard interferon who had failed to respond or who had relapsed. We enrolled 69 patients with chronic hepatitis C and compensated liver disease: 45 were men, 65 were Caucasian, 48 were infected with genotype 1 hepatitis C virus. By random assignment, 35 received 600 mg ribavirin/day (group A), whereas the other 34 received 1,000 mg (< or = 75 kg body wt) or 1,200 mg/day (>75 kg body wt) (group B). At baseline, the two groups were well matched for demographic and laboratory features. In both groups, mean serum levels of alanine aminotransferase (ALT) and hepatitis C viral (HCV) RNA levels fell promptly and remained significantly lower than baseline throughout 24 weeks of therapy. There was no significant difference in mean levels of ALT or HCV RNA during therapy or at the end of follow-up (24 weeks after cessation of therapy). At the end of 24 weeks of posttherapy follow-up, 12 patients in each group had undetectable HCV RNA in serum, whereas 11 (31%) in group A and 9 (26.5%) in group B had normal serum ALT levels. The lower doses of ribavirin (group A) were tolerated better. In conclusion, in previous nonresponders or relapsers to interferon done, combination therapy with interferon-alpha2b (3 MU thrice weekly) + 600 mg ribavirin/day is tolerated better and is as effective as interferon plus higher (standard) doses of ribavirin (1,000-1,200 mg/day).

Increased heme oxygenase activity in splanchnic organs from portal hypertensive rats: role in modulating mesenteric vascular reactivity

BACKGROUND/AIMS

We have recently demonstrated that heme oxygenase-1 is upregulated in splanchnic organs of portal hypertensive rats. In the present study, we assessed whether heme oxygenase enzymatic activity is increased in splanchnic organs of portal hypertensive rats, and the relative contribution of heme oxygenase and nitric oxide synthase to the vascular hyporeactivity in portal hypertension.

METHODS

Heme oxygenase activity was measured in splanchnic organs of portal hypertensive and sham-operated rats. The effects of heme oxygenase and nitric oxide synthase inhibition on pressure responses to potassium chloride and methoxamine were assessed in perfused mesenteric vascular beds of portal hypertensive and sham-operated rats.

RESULTS

Heme oxygenase activity was increased in the mesentery, intestine, liver, and spleen of portal hypertensive rats. The hyporeactivity to potassium chloride in portal hypertensive rats was overcome after simultaneous inhibition of both heme oxygenase and nitric oxide synthase, but only partially attenuated after nitric oxide synthase inhibition alone. The hyporeactivity to methoxamine was completely reversed after nitric oxide synthase blockade.

CONCLUSIONS

These results demonstrate that heme oxygenase activity is increased in splanchnic organs of portal hypertensive rats. They also suggest that heme oxygenase contributes to the hyporeactivity to potassium chloride, but not to methoxamine, in portal hypertensive rats.

Hepatitis C: a review and update

The hepatitis C virus is an RNA virus that is a major cause of acute and chronic hepatitis. It is contracted chiefly through parenteral exposure to infected material such as blood transfusions or injections with dirty needles. Those at highest risk for development of hepatitis C are injection-drug users, people who snort cocaine with shared straws, and health care workers who are at risk for needle-stick and other exposures. Although the incidence of acute hepatitis C infection has fallen dramatically in the United States during the past decade, the prevalence of infection remains high (approximately 2.7 million Americans) because chronic hepatitis C develops in about 75% of those infected. Both acute and chronic hepatitis C are asymptomatic in most patients. However, chronic hepatitis C is a slowly progressive disease and results in severe morbidity in 20% to 30% of infected persons. Chronic hepatitis C is associated with a host of extrahepatic manifestations, many of which may be seen by dermatologists. The most frequent of these are mixed cryoglobulinemia with leukocytoclastic vasculitis and porphyria cutanea tarda. (J Am Acad Dermatol 2001;44:159-79.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be familiar with the essentials of the virology of the hepatitis C virus and the major features of the human diseases caused by hepatitis C viral infection; the extrahepatic manifestations of hepatitis C viral infection, with particular emphasis upon dermatologic manifestations, including leukocytoclastic vasculitis, porphyria cutanea tarda, and lichen planus; and the current methods of management of hepatitis C and its extrahepatic manifestations.

The Porphyrias

The porphyrias are a diverse group of metabolic diseases. Major manifestations are episodic neurovisceral attacks of pain or other neurologic features, and/or dermatologic abnormalities. It is essential that a clear diagnosis be established prior to planning management. In our experience, most patients referred with a presumptive diagnosis of "porphyria" do not have true porphyria at all, but rather have syndromes of other etiologies associated with mild, nonspecific increases in urinary porphyrin excretion (secondary porphyrinurias). The management of the acute or inducible porphyrias depends upon prevention and prompt, aggressive management of acute attacks. The latter includes nutrition (at least 300 g/d carbohydrate plus adequate protein), analgesia, and intravenous heme. The management of active porphyria cutanea tarda involves iron depletion by therapeutic phlebotomy and cessation of precipitating or exacerbating factors, especially alcohol and estrogens. When chronic hepatitis C and/or HIV infection are present, they should also be treated. The management of protoporphyria involves ensuring adequate iron stores, and avoidance of hepatotoxic or cholestatic factors. Liver transplantation may be life-saving in the small minority of patients who develop progressive protoporphyric liver disease. A few patients with congential erythropoietic porphyria (Günther's disease) have been treated successfully by transplantation of bone marrow from a normal donor. In the future, this and other forms of porphyria may be treated by specific gene therapy. Such efforts are now under development, but they are not yet ready for human trials in the US.

Ubiquitin as a marker of cell injury in nonalcoholic steatohepatitis

Ubiquitin (UB), an intracellular protein that binds to other proteins to target them for proteolysis, is associated with Mallory hyalin (MH), which supports a biopsy diagnosis of nonalcoholic steatohepatitis (NASH). We analyzed 54 liver biopsy specimens from 49 patients with a clinical diagnosis of NASH for immunoreactive UB and multiple features of necroinflammation, fibrosis, and Prussian blue-positive iron to determine whether the presence of immunoreactive UB increases detection of MH or correlates with other features of cell injury or mutations of the HFE gene. MH and UB were graded. Analysis for HFE gene mutations was performed in 48 patients. Biopsy diagnoses were distributed as follows: NASH, 42; steatosis, 10; and nonspecific changes, 2. UB was present in 20 specimens and MH in 23. Of 31 specimens with 0 MH, 6 had UB; of 14 with 1 + (questionable) MH, 7 had 1+ or 2+ UB. UB correlated positively and significantly with the diagnosis and grade of NASH, presence of MH, cell swelling, lobular inflammation, and fibrosis. Immunostaining for UB may enhance detection of MH in questionable cases, support the diagnosis of NASH, and indicate which patients may be at risk for progression of disease.

Management of recurrent hepatitis C after liver transplantation: a concise review

Recurrent hepatitis C infection and subsequent graft failure are increasingly recognized problems after orthotopic liver transplantation. Although many prospective therapeutic, controlled trials in primary hepatitis C disease have been reported, large-scale studies are yet to be performed in patients with posttransplant recurrent hepatitis C after liver transplantation. In this review, we summarize the current literature on the therapeutic approaches for recurrent hepatitis C and discuss the results of published studies on therapy with ribavirin or interferon (IFN) alone and on combination therapy with IFN plus ribavirin. Further, we discuss results of prophylactic approaches to the problem of recurrent hepatitis C after transplant. Finally, we discuss additional aspects of anti-hepatitis C virus therapy after liver transplantation.

Induction of the heme oxygenase-1 gene by metalloporphyrins

Induction of expression of heme oxygenase-1 (HO-1) has been studied in primary cultures of chick embryo liver cells and in the LMH line of avian hepatoma cells. Cells were transiently transfected with selected constructs containing portions of the 5'-untranslated (promoter) region of the HO-1 gene linked to luciferase as reporter gene. LMH cells that had been stably transfected with selected wild type or mutant constructs were also studied. Metalloporphyrins, especially Fe protoporphyrin (heme) and Co protoporphyrin strongly induced luciferase expression in both types of transfected cells. Low concentrations of Zn mesoporphyrin, an inhibitor of HO activity, exerted a synergistic effect on heme-, but not Co protoporphyrin-dependent induction. The antioxidant and &bond;SH donor N-acetyl cysteine had little effect on the metalloporphyrin-dependent inductions of HO-1, in contrast to its marked inhibitory effect on the sodium arsenite-dependent induction of the HO-1 gene. Deletional analysis showed that the key element(s) required for the metalloporphyrin-dependent induction of HO-1 is located between -3.6 and -5.6 kb upstream of the transcription starting point. Data from electrophoretic mobility shift and site-directed mutagenesis experiments excluded a role for consensus AP-1 binding elements at -1576, -3647, or -4578 in the inductions produced by heme or Co protoporphyrin.

Outcomes research in chronic viral hepatitis C: effects of interferon therapy

Although chronic hepatitis C (CHC) is often mild and asymptomatic, it may lead to decompensated hepatic cirrhosis and death. CHC is now the single most important indication for liver transplantation in North America. CHC is also an important cause of morbidity. Recent work is reviewed and shows that the health-related quality of life (HRQOL) of patients with CHC is markedly reduced compared with that of age- and sex-matched controls. For as yet unknown reasons, this reduction is more severe in CHC patients than in those with chronic hepatitis B. Successful therapy of CHC with type 1 interferons (IFNs) leads to substantial improvement - to nearly normal levels - in patients' HRQOL. In addition, IFN or IFN plus ribavirin therapy for CHC is highly cost effective, despite its limited long term efficacy; estimates of the costs to gain one year of quality-adjusted life range from no cost (that is, therapy is cost saving) to US$11,400 (for those most difficult to cure). Thus, despite the limited effectiveness of current therapies for CHC, they are fully justified based on their beneficial effects on patients' HRQOL and their cost effectiveness.

Iron reduction as an adjuvant to interferon therapy in patients with chronic hepatitis C who have previously not responded to interferon: a multicenter, prospective, randomized, controlled trial

Hepatic iron concentration has consistently been observed as being directly correlated with the response to interferon therapy in chronic hepatitis C virus (HCV). We therefore conducted a randomized, controlled trial comparing iron reduction by phlebotomy with iron reduction followed by retreatment with interferon in 96 patients with chronic hepatitis C who had previously not responded to a course of interferon. During the initial phase when all patients were undergoing phlebotomy, we found that serum alanine transaminase (ALT) activities decreased but by less than 50% from baseline in 67 patients (89%), decreased by more than 50% in 12 patients (13%) and became normal in 9 patients (9%) with no overall change in HCV-RNA levels. Subsequently no patient in either treatment group achieved a sustained virologic response. Improvements in necroinflammatory changes were noted in liver biopsy specimens in those patients receiving phlebotomy plus interferon (mean index 8.59 vs. 7.37, P <. 05). A slight but not statistically significant decrease in histologic activity index was noted in those subjects treated by phlebotomy alone (mean index 8.4 vs. 7.75, P not significant). We conclude that, although prior phlebotomy therapy does not improve the rate of sustained response to interferon retreatment, it does result in less liver injury manifested by a decrease in serum transaminase activity and a slight improvement in liver histopathology.

Upstream regulatory elements in chick heme oxygenase-1 promoter: a study in primary cultures of chick embryo liver cells

Previously, chick heme oxygenase-1 (cHO-1) gene was cloned by us and two regions important for induction by sodium arsenite were identified. These two regions were found to contain consensus sequences of an AP-1 (-1580 to -1573) and a MRE/cMyc complex (-52 to -41). In the current study, the roles of these two elements in mediating the sodium arsenite or cobalt chloride dependent induction of cHO-1 were investigated further. DNA binding studies and site-directed mutagenesis studies indicated that both the AP-1 and MRE/cMyc elements are important for the sodium arsenite induction, while cobalt chloride induction involves only the AP-1 element. Electrophoretic mobility shift assays showed that nuclear protein binding to the AP-1 element was increased by both sodium arsenite or cobalt chloride treatment, whereas the binding of proteins to the MRE/cMyc element showed a high basal expression in untreated cells and the binding activity was only slightly increased by sodium arsenite treatment. Site-directed mutagenesis studies showed that, to completely abolish sodium arsenite induction, both the AP-1 and MRE/cMyc elements must be mutated; mutation of either element alone resulted in only a partial effect. In contrast, a single mutation at AP-1 element was sufficient to reduce the cobalt chloride induction almost completely. The MRE/cMyc complex plays a major role in the basal level expression, and shares some similarities to the upstream stimulatory factor element (USF) identified in the promoter regions of mammalian HO-1 genes and other stress regulated genes. Because sodium arsenite is known to cause oxidative stress and because activation of AP-1 proteins has been shown to be a key step in the oxidative stress response pathway, we also explored the possibility that the induction of the cHO-1 gene by sodium arsenite is mediated through oxidative stress pathway(s) by activation of AP-1 proteins. We found that pretreatment with antioxidants (N-acetyl cysteine or quercetin) reduced the induction of the endogenous cHO-1 message or cHO-1 reporter construct activities induced by sodium arsenite or cobalt chloride. These antioxidants also reduced the protein binding activities to the AP-1 element in the electrophoretic mobility shift assays. In summary, induction of the cHO-1 gene by sodium arsenite or cobalt chloride is mediated by activation of the AP-1 element located at -1,573 to -1,580 of the 5'UTR.

Iron-induced liver injury

Iron, either in the form of heme or non-heme compounds, is essential to life, but it can also pose serious health risks. The liver is a principal target for iron toxicity because it is chiefly responsible for taking up and storing excessive amounts of iron. The major hepatic toxicities of iron overload include damage to multiple cell types (hepatocytes, Kupffer cells, hepatic stellate cells) and to multiple subcellular organelles (mitochondria, lysosomes, and smooth endoplasmic reticulum). Heavy iron overload, as occurs in primary (hereditary) or secondary forms of hemochromatosis, may cause cirrhosis, liver failure, and hepatocellular carcinoma. In addition, iron has been shown to be a contributory factor in the development or progression of alcoholic liver disease, nonalcoholic liver steatohepatitis, chronic viral hepatitis, prophyria cutanea tarda, and, perhaps, in alpha 1-antitrypsin deficiency and end-stage liver disease, regardless of cause.

Iron reduction before and during interferon therapy of chronic hepatitis C: results of a multicenter, randomized, controlled trial

Patients with chronic hepatitis C and low serum and hepatic iron stores may have an improved response to interferon (IFN). We tested whether iron reduction before and during IFN therapy would lead to an improved sustained biochemical and virological response compared with IFN alone. Eighty-two previously untreated patients with chronic hepatitis C were randomized to either: group A IFN-alpha2b 3 MU 3 times per week for 6 months, or group B iron reduction before and during IFN-alpha2b 3 MU 3 times per week for 6 months. Group B patients had lower mean serum alanine transaminase (ALT) levels than group A patients during treatment and follow-up. Group B patients had significantly lower mean hepatitis C virus (HCV)-RNA levels at treatment weeks 4 and 12 (P <.05). Serum HCV RNA was undetectable at the end of treatment in 15 group B patients compared with 7 group A patients (P =.03); 7 group B patients and 3 group A patients had persistently undetectable serum HCV RNA 24 weeks after the end of therapy (P =.20). Paired pre- and posttreatment liver biopsies in 18 group B patients demonstrated significant improvements in 2 of the 3 inflammation scores of the Knodell histological activity index (P <. 05). No changes occurred in the paired biopsies from 15 group A patients. We conclude that iron reduction via therapeutic phlebotomy improves the end-of-treatment virological and histological response to short-term IFN therapy. Additional studies are needed to determine if iron reduction in combination with higher doses or longer duration of IFN may be of benefit.

Hepatotoxicity due to troglitazone: report of two cases and review of adverse events reported to the United States Food and Drug Administration

Two patients (a 48-year-old woman and a 62-year-old man) developed clinical and laboratory signs of hepatotoxicity due to troglitazone (Rezulin), a thiazolidinedione used in treatment of diabetes mellitus. There was no clear clinical evidence of drug allergy, although the woman experienced colitis before the onset of recognized hepatotoxicity. Liver biopsies showed bridging necrosis and fibrosis in the woman and hepatitis with granuloma formation in the man. The abnormalities in liver chemistries resolved promptly upon cessation of the drug. Cases involving 46 patients reported to the United States Food and Drug Administration are also reviewed. Troglitazone is a useful new oral antihyperglycemic agent, but in about 1.9% of patients hepatotoxicity has occurred, which may be severe and even fatal. Frequent monitoring of serum liver chemistries in patients taking the drug is essential.

Effects of phenylarsine oxide on expression of heme oxygenase-1 reporter constructs in transiently transfected cultures of chick embryo liver cells

Heme oxygenase catalyzes the first and rate-controlling step of heme catabolism. Induction of heme oxygenase-1 can be caused by numerous factors, including heme, other metalloporphyrins, transition metal ions, heat shock, ultraviolet light, phorbol esters, sodium arsenite, and phenylarsine oxide (PAO). Induction of this enzyme may protect cells from oxidative damage. Using heme oxygenase-1 promoter/reporter gene constructs, we have previously reported that the sodium arsenite-mediated induction of heme oxygenase-1 in chick embryo liver cells and chicken hepatoma (LMH) cells involves an AP-1 element. We have now investigated whether the PAO-mediated induction of heme oxygenase-1 also involves an AP-1 element. Primary cultures of chick embryo liver cells were transiently transfected with heme oxygenase-1 promoter/reporter gene constructs, treated with PAO, and reporter gene activities were measured. We found that the PAO-mediated increase in reporter gene activity was dose- and time-dependent. This activity was decreased by prior treatment with N-acetylcysteine. Studies with mutated constructs showed that both an AP-1 element and a metal responsive element are involved in the PAO-mediated induction of the heme oxygenase-1 reporter construct. Electrophoretic mobility shift assays showed that nuclear proteins from PAO-treated cells had increased binding to an AP-1 probe, and that this increase was abrogated by N-acetylcysteine. These findings support the hypothesis that the PAO-mediated induction of heme oxygenase-1 is caused by activation of AP-1 and MRE/cMyc elements and may involve nuclear proteins whose states of phosphorylation determine binding to regulatory elements, and thus the level of expression of heme oxygenase-1.

Effects of antidepressants and benzodiazepine-type anxiolytic agents on hepatic porphyrin accumulation in primary cultures of chick embryo liver cells

Patients with any of the acute porphyrias may suffer from acute attacks. If these patients are treated with certain drugs, such as barbiturates, the likelihood of developing an attack is increased. Patients treated with antidepressants or benzodiazepine-type anxiolytics also could be placed at increased risk of developing porphyric attacks because little is known about the potential for some of these drugs to induce attacks. Primary cultures of chick embryo liver cells were used to study the effects of selected antidepressants and anxiolytics on porphyrin accumulation. Cells were treated with desferrioxamine (to partially block heme synthesis, simulating conditions encountered in porphyric patients) and increasing concentrations (3.16-1000 microM) of the evaluated drugs. Twenty hours later, porphyrin accumulation was measured. The drugs included four antidepressants and five benzodiazepine-type anxiolytics. The antidepressants bupropion and nefazodone significantly increased porphyrin accumulation when given with desferrioxamine, whereas neither fluoxetine nor paroxetine increased porphyrin accumulation. The benzodiazepine-type anxiolytic agents oxazepam, lorazepam, diazepam, triazolam, and midazolam all significantly increased porphyrin accumulation when given with desferrioxamine. Dose-response studies showed that diazepam, midazolam, and triazolam produced significant increases even at the lowest concentration tested (3.16 microM), whereas lorazepam and oxazepam required higher concentrations (>/=10 microM). These studies suggest that patients with acute porphyrias may be at greater risk for developing porphyric attacks when treated with bupropion or nefazodone compared with fluoxetine or paroxetine, and that the evaluated benzodiazepine derivatives should be administered with caution. Among the latter, low doses of lorazepam and oxazepam may be safer than those of diazepam, midazolam, and triazolam.

Heme biosynthesis in a chicken hepatoma cell line (LMH): comparison with primary chick embryo liver cells (CELC)

5-Aminolevulinic acid synthase (ALA synthase), the rate-controlling enzyme of hepatic heme biosynthesis, is feed-back repressed by heme. In the liver, chemicals such as barbiturates markedly induce ALA synthase, especially in the presence of partial defects of heme biosynthesis. The inducibility and regulation of ALA synthase have been investigated using a variety of models, including intact animals and liver cell culture systems. A widely used model that closely approximates what occurs in vivo and in humans is that of primary cultures of chick embryo liver cells (CELCs). However, CELCs have some limitations: the cells obtained are somewhat heterogeneous; isolation and culture must be repeated every week resulting in weekly variations; and cells are short-lived limiting the feasibility of time-course and transfection studies. The aim of this study was to determine if LMH cells, a chick hepatoma cell line, are a good model comparable to that of CELCs. In both cells similar patterns of response of, ALA synthase activities and mRNA levels, and of porphyrin accumulation were obtained following treatments known to affect heme biosynthesis. Similarly, heme repressed ALA synthase mRNA levels in both cell types and ALA synthase activities in LMH cells. We conclude that LMH cells are a useful model for the study of hepatic heme biosynthesis and regulation of ALA synthase.

Heme oxygenase: recent advances in understanding its regulation and role

Heme oxygenase (HO) is responsible for the physiological breakdown of heme into equimolar amounts of biliverdin, carbon monoxide, and iron. Three isoforms (HO-1, HO-2, and HO-3) have been identified. HO-1 is ubiquitous and its mRNA and activity can be increased several-fold by heme, other metalloporphyrins, transition metals, and stimuli that induce cellular stress. HO-1 is recognized as a major heat shock/stress response protein. Recent work from our laboratory has demonstrated several potential consensus regulatory elements in the 5'-untranslated region (UTR) of HO-1, including activator protein 1 (AP-1), metal responsive element (MRE), oncogene c-myc/max heterodimer binding site (Myc/Max), antioxidant response element (ARE), and GC box binding (Sp1) sites. Using deletion-reporter gene constructs, we have mapped sites that mediate the arsenite-dependent induction of HO-1, and we have shown that components of the extracellular signal-regulated kinase (ERK) and p38 (a homologue of the yeast HOG1 kinase), but not c-jun N-terminal kinase (JNK), mitogen-activated protein (MAP) kinase pathways are involved in arsenite-dependent upregulation. In contrast, HO-2 is present chiefly in the brain and testes and is virtually uninducible. HO-3 has very low activity; its physiological function probably involves heme binding. Products of the HO reaction have important effects: carbon monoxide is a potent vasodilator, which is thought to play a key role in the modulation of vascular tone, especially in the liver under physiological conditions, and in many organs under "stressful" conditions associated with HO-1 induction. Biliverdin and its product bilirubin, formed in most mammals, are potent antioxidants. In contrast, "free" iron increases oxidative stress and regulates the expression of many mRNAs (e.g., DCT-1, ferritin, and transferrin receptor) by affecting the conformation of iron regulatory protein (IRP)-1 and its binding to iron regulatory elements (IREs) in the 5'- or 3'-UTRs of the mRNAs.

Non-alcoholic steatohepatitis and iron: increased prevalence of mutations of the HFE gene in non-alcoholic steatohepatitis

BACKGROUND/AIMS

Non-alcoholic steatohepatitis (NASH) is increasingly recognized, and its pathogenesis is believed to involve increased oxidative stress. Elevated levels of serum ferritin and positive liver iron stains are often observed in patients with NASH, and the pathogenesis of liver injury due to iron is also thought to involve oxidative stress. The aim of this study was to determine whether there is an association of NASH and mutations in the HFE gene associated with hereditary hemochromatosis (HHC).

METHODS

Clinical, laboratory, and histopathological data on all 57 subjects with a final diagnosis of NASH seen between August 1990 and August 1997 at our Liver Center were analyzed. Thirty-six Caucasian subjects (23 men) with NASH underwent mutational analyses of HFE gene mutations performed. The prevalence of HFE gene mutations was compared to that in 348 Caucasian normal controls. Data were analyzed by both parameteric and non-parametric methods with similar results.

RESULTS

One subject (2.8%) with NASH was homozygous for the C282Y mutation and six (16.7%) were heterozygous, compared with 0%, and 11.2%, respectively, of controls. Two (5.6%) subjects with NASH were homozygous for the H63D mutation and 16 (44.4%) were heterozygous, whereas 2.9% and 26.4%, respectively, of controls had these genotypes. The prevalence of heterozygosity (61.1%) for either mutation was significantly higher in subjects with NASH than in controls (38%) (p = 0.008), and the prevalence of homozygosity or heterozygosity combined in NASH subjects (69.4%) was significantly higher than for controls (40.5%, p = 0.001). Sex (63-67% male) and age at diagnosis of NASH did not differ between those with or without HFE mutations, but men with NASH were significantly more likely than women to have the H63D mutation (15/23 vs. 3/13, p<0.05) Levels of serum ferritin, iron, transferrin saturation levels, and the degree of hepatic iron staining were significantly higher (p<0.05) in subjects with NASH who carried an HFE mutation than in those without. Differences in hepatic iron concentrations or hepatic iron indices between NASH subjects with and without HFE mutations were not significant. Those with C282Y mutations had significantly more hepatic fibrosis than those without (p<0.05). Those with HFE mutations had significantly higher levels of serum ALT (90+/-11 [mean +/- SE]) than those without (55+/-6; p = 0.02).

CONCLUSION

The prevalences of the HFE gene mutations associated with hereditary hemochromatosis are increased among North American subjects with NASH.

Effects of selected antihypertensives and analgesics on hepatic porphyrin accumulation: implications for clinical porphyria

When patients with acute porphyrias are treated with antihypertensives and analgesics, they could be placed at increased risk of developing porphyric attacks, since little is known about the potential for many of these drugs to induce these attacks. We used primary chick embryo liver cells, which maintain intact heme synthesis and regulation, to study the effects of antihypertensives and analgesics on porphyrin accumulation. Cells were treated with desferrioxamine to block heme synthesis partially, simulating conditions encountered in porphyric patients. Typically, cells were treated for 20 hr with the test drugs (3.16 to 1000 microM), along with desferrioxamine. Porphyrins were measured spectrofluorometrically, as uro-, copro,- and protoporphyrin. The evaluated drugs included six antihypertensives (two calcium channel blockers, an angiotensin receptor antagonist, and three inhibitors of angiotensin converting enzyme) and eight analgesics. Of the calcium channel blockers tested, nifedipine greatly increased porphyrin accumulation, whereas diltiazem caused only a slight increase. Losartan (an angiotensin receptor antagonist), captopril, or lisinopril (two angiotensin converting enzyme inhibitors) produced only small increases in porphyrin accumulation. In contrast, enalapril (another angiotensin converting enzyme inhibitor) substantially increased porphyrin accumulation when given in high concentrations. Among the analgesics tested, fentanyl and tramadol produced the highest porphyrin accumulations. Nalbuphine, hydrocodone, oxycodone, and dezocine were moderately or weakly porphyrogenic, whereas buprenorphine and morphine did not increase porphyrin accumulation. These studies suggest that patients with acute porphyrias may be at greater risk for developing porphyric attacks when treated with nifedipine (compared with diltiazem), enalapril (compared with captopril or lisinopril), and tramadol (compared with the other analgesics).

IFN-alpha receptor mRNA expression in a United States sample with predominantly genotype 1a/I chronic hepatitis C liver biopsies correlates with response to IFN therapy

Our aim was to assess whether, in the United States, with the predominant hepatitis C viral (HCV) genotypes 1a/I and 1b/II, hepatic interferon-alpha receptor (IFNAR) mRNA expression correlated with response to IFN therapy, levels of HCV RNA, or histologic activity index (HAI). Nine of 24 patients (38%) had an initial response to IFN treatment, 5 of whom (21%) had a sustained response. The corrected hepatic IFNAR mRNA expression (measured by RT-PCR) for the sustained responder group (mean +/- SE, 0.16 +/- 0.06, n = 5) was significantly higher than for the nonresponding group (0.059 +/- 0.01, n = 15) (p < 0.02). Patients who relapsed had an intermediate value (0.092 +/- 0.029, n = 4). Higher IFNAR expression was inversely correlated with a lower serum HCV RNA titer (p < 0.01), and responders to IFN treatment tended to have a lower titer of HCV RNA (p = 0.056). We found no significant correlation between the amounts of IFNAR with (1) the total HAI (low HAI < or = 7, IFNAR 0.076 +/- 0.013, n = 10; high HAI > or = 8, IFNAR 0.092 +/- 0.027, n = 14, ns) or (2) individual inflammation, necrosis, or fibrosis components of the HAI. As with Japanese HCV patients with genotypes 1b/II-2b/IV, higher hepatic IFNAR mRNA expression in the United States with predominant genotypes 1a/I and 1b/II appears to correlate with response to IFN therapy and a low HCV RNA titer but not with the total HAI or its components.

Hepatic iron concentration: noninvasive estimation by means of MR imaging techniques

PURPOSE

To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy.

MATERIALS AND METHODS

Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentration and hepatic MR imaging with several spin-echo and gradient-recalled-echo (GRE) techniques. Correlations between MR imaging parameters and the hepatic iron concentration were determined.

RESULTS

Inverse curvilinear relationships were noted between several MR parameters and hepatic iron concentrations. GRE sequences with short repetition and echo times were more accurate and precise than spin-echo sequences for the estimation of hepatic iron concentration. A GRE sequence with a repetition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degrees showed close correlation between the hepatic iron concentration and the natural logarithm of the ratio of the signal intensity of liver to the SD of background noise (r = -0.94) and low coefficient of variation (12%).

CONCLUSION

MR imaging with these parameters is a rapid, noninvasive, and accurate modality for estimation of hepatic iron concentration; it is sufficiently accurate and precise to obviate liver biopsy for the purpose of measuring hepatic iron concentration.

Increased heme oxygenase-1 gene expression in liver cells and splanchnic organs from portal hypertensive rats

Heme oxygenase (HO) catalyzes the conversion of heme into biliverdin, iron, and carbon monoxide (CO). Two isoforms of HO have been identified: the inducible HO-1 and the constitutive HO-2. CO, like nitric oxide, is an endogenous vasodilator that could contribute to modulation of systemic and local vascular tone. The aim of the present study was to determine the expression of HO isoforms in liver cells and splanchnic organs from portal hypertensive (PH) and sham-operated (SO) rats. Liver cells (hepatocytes, Kupffer and stellate cells), and splanchnic organs (liver, mesentery, intestine, colon, and spleen) were isolated from PH and SO rats. Expression of HO mRNA and protein was assessed by reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. In SO rats, HO-1 mRNA expression was only detected in spleen. In contrast, in PH rats, HO-1 mRNA was expressed in hepatocytes, Kupffer cells, and in all the splanchnic organs studied. Moreover, levels of HO-1 protein in splanchnic organs were significantly higher in PH rats than in SO animals. In addition, HO-2 expression was observed in all liver cell types and splanchnic organs studied from both PH and SO rats. These results indicate that HO-2 is expressed in parenchymal and nonparenchymal liver cells, as well as splanchnic organs, of both PH and SO rats. In addition, HO-1 is up-regulated in hepatocytes and splanchnic organs of PH rats, compared with SO animals, suggesting a possible pathophysiological role of HO-1 in chronic portal hypertension.

The value of intravenous heme-albumin and plasmapheresis in reducing postoperative complications of orthotopic liver transplantation for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is marked by a deficiency of ferrochelatase, which occurs in all cells and tissues, preventing effective conversion of proto porphyrin IX to heme and thereby blocking effective feedback inhibition of heme synthesis. The major source of the excess protoporphyrin is the bone marrow. Protoporphyrin IX may accumulate, with resultant toxicity chiefly of the marrow, skin, nervous system, and liver. Orthotopic liver transplantation (OLT) is, at present, the only adequate intervention for severe liver compromise secondary to protoporphyrin deposition, but it has been complicated by severe photosensitivity and polyneuropathy. Intravenous heme and plasmapheresis have been proposed but not previously reported as means to reduce the protoporphyrin burden before liver transplantation. We report a man with EPP who underwent preoperative heme-albumin administration and plasmaphereses that led to marked reductions in plasma and erythrocyte protoporphyrin levels. His OLT was uneventful, and he developed neither polyneuropathy nor exacerbation of photosensitivity.

Role of HFE gene mutations in liver diseases other than hereditary hemochromatosis

Heavy iron overload, as occurs in primary and secondary hemochromatosis, may cause fibrosis of parenchymal organs, including the heart, liver, and pancreas, and it is a risk factor for the development of hepatocellular carcinoma. Recent evidence indicates that lesser degrees of hepatic iron deposition are also risk factors for nonhemochromatotic liver disease. For example, several recent studies showed extraordinarily high prevalences (about 60% to 75%) of HFE mutations in patients with porphyria cutanea tarda and significantly increased prevalences of these mutations in patients with nonalcoholic steatohepatitis from Australia and the United States. It is less well established that the prevalence of the HFE mutations is increased in alcoholic liver disease and in chronic viral hepatitis, but in both conditions, patients harboring one of these mutations, especially C282Y, are more likely to have advanced hepatic fibrosis or cirrhosis. Thus, these mutations both incite and exacerbate nonhemochromatotic liver disease. In this review, we summarize current knowledge of these associations and emphasize important unresolved questions that require further study.

Reduction of health-related quality of life in chronic hepatitis C and improvement with interferon therapy. The Consensus Interferon Study Group

The natural history, prognosis, and clinical significance of chronic hepatitis C are highly variable and somewhat controversial. The purpose of this study was to evaluate the effect of chronic hepatitis C infection on patients' perceptions of health-related quality of life (HRQOL) and to evaluate whether treatment with interferon improves HRQOL. A total of 642 patients with compensated liver disease who were enrolled in a multicenter trial of interferon therapy for chronic hepatitis C had evaluation of HRQOL using the SF-36 and other instruments derived from the Medical Outcomes Study (MOS). These instruments were self-administered by patients at baseline and at the end of a 24-week post-treatment observation period after 24 weeks of interferon treatment. Patients with chronic hepatitis C were compared with healthy controls (n = 750) selected from a representative sample of adults in the United States. Unadjusted and age/gender-adjusted results were similar, as were analyses using parametric or nonparametric methods. Compared with healthy controls, patients with chronic hepatitis C at baseline had lower HRQOL on all eight scales of the SF-36 (P <.001 for all). Patients without cirrhosis (n = 284 ) showed similar although slightly smaller differences. The differences were highly significant, clinically and socially relevant, and greatest for those scales that were more reflective of physical than mental or emotional disease. Patients who had a sustained viral response to interferon therapy (n = 41) exhibited marked improvements in HRQOL, and these improvements exceeded those of nonresponders on 13 of 14 HRQOL scales (8 were statistically significant). Similar improvements were noted in patients with sustained biochemical responses. The authors concluded that patients with chronic hepatitis C with or without cirrhosis have markedly reduced HRQOL. Patients who had a sustained response (virological or biochemical) to interferon therapy experienced significant improvements in perceived wellness and functional status. Successful interferon therapy provides meaningful improvements in HRQOL in patients with chronic hepatitis C.

Inefficient recognition of autologous viral sequences by intrahepatic hepatitis C virus-specific cytotoxic T lymphocytes in chronically infected subjects

Cytotoxic T lymphocytes (CTL) capable of recognizing prototype hepatitis C virus (HCV) sequences have been shown to localize to the liver in chronically infected individuals, where they are thought to influence hepatic inflammation and viral replication. We isolated three intrahepatic CD8(+) CTL clones from two individuals with chronic HCV infection and compared the recognition of prototype and autologous HCV sequences. These CTL recognized epitopes within the NS2 (amino acids 957-964) or NS3 (amino acids 1402-1410 and 1406-1415) proteins in the context of HLA B37, B8, or A2.1, respectively. The corresponding predominant autologous HCV sequences (SDWAANGL, ELAAKLVGL, and ALRGMGVNAV, respectively) differed from the HCV-1 sequences used for screening (RDWAHNGL, ELAAKLVAL, and KLVALGINAV, respectively) at one to five residues. For each CTL clone, recognition of the autologous HCV sequence required significantly higher peptide concentrations than did recognition of the HCV-1 sequence; for two of the clones, recognition was minimal or absent at peptide concentrations as high as 25 microM. These data show that intrahepatic HCV-specific CD8(+) CTL clones can be relatively inefficient at recognizing autologous viral epitopes. Inefficient recognition of autologous HCV sequences should influence the interpretation of data generated using prototype HCV sequences and might have implications in vivo.

Porphyrin loading of lipofuscin granules in inflamed striated muscle

To further the understanding of oxidative effects on inflammation injury to muscle fiber structure, fluorescent imaging analysis of human striated muscle tissues from a variety of inflammatory or postinflammatory etiologies was undertaken in a search for accumulated coproporphyrin, a red autofluorescent byproduct of heme biosynthesis that would theoretically be formed under oxidative insult. Using a differential excitation method of in situ analysis, porphyrin autofluorescence was detected in intact fibers within the context of the yellow autofluorescent subsarcolemmal lipofuscin granules. Relative measurements of porphyrin concentration in the granules from different patients indicated that the acute/subacute inflammatory specimens grouped significantly higher than the more chronic inflammatory and nonpathological specimens. Myoglobin was also found to be associated with the granules. Myoglobin heme iron could potentially serve as a Fenton reagent for the intracellular generation of hydroxyl radicals, which are responsible for the oxidation of the porphyrinogens. High-performance liquid chromatography analysis of extracted dense particles revealed coproporphyrin as the sole porphyrin present. The observation of coproporphyrin within lipofuscin granules, previously unreported, suggests that lipofuscin accumulation in striated muscle may begin under conditions of acute oxidative stress, as marked by the oxidation of extramitochondrial porphyrinogens that are immediately incorporated into the granules.

Enhanced phenotypic expression of alpha-1-antitrypsin deficiency in an MZ heterozygote with chronic hepatitis C

A middle-aged white man of Scotch-Irish ancestry, being treated for chronic hepatitis C, was found to be heterozygous for alpha1-antitrypsin deficiency (PiMZ phenotype) after diagnostic PAS-positive, diastase-resistant globules were detected in a liver biopsy. The globules had not been present in a biopsy obtained 4 yr previously. He was also found to be heterozygous for the cys282tyr mutation of the HFE gene, which is the chief cause of HLA-linked hereditary hemochromatosis (HHC). His liver disease progressed over 4 yr from mild hepatitis to moderate hepatitis with cirrhosis despite therapy with interferon-alpha, and phlebotomy plus interferon. These conditions appeared to have synergistic effects, with the chronic viral hepatitis unmasking the alpha1AT deficiency, and the alpha1AT deficiency (and possibly the heterozygosity for HHC), exacerbating the course of the hepatitis C.

Interleukin-8 and hIRH (SDF1-alpha/PBSF) mRNA expression and histological activity index in patients with chronic hepatitis C

Recombinant human intercrine reduced in hepatomas (hIRH)/stromal cell-derived factor 1 (SDF1-alpha)/pre-B-cell growth-stimulating factor (PBSF), a new chemokine, exhibits an in vitro chemotaxis to neutrophils and a mixed in vivo chemotactic activity to neutrophils, lymphocytes, and monocytes in a rat intradermal injection model. We have investigated the messenger RNA (mRNA) expression of interleukin-8 (IL-8) and hIRH, in chronic hepatitis C of differing severity. Levels of expression of IL-8 and hIRH mRNA obtained from 37 human liver biopsy samples were measured by reverse-transcription and semiquantitative polymerase chain reaction (RT-PCR) amplification. We examined the correlation between mRNA expression and components of the histological activity index (HAI). Patients with HAI > or = 8 had a significantly higher corrected IL-8 mRNA expression ratio (0.24 +/- 0.13 [mean +/- SD]; n = 20) than those with HAI < or = 7 (0.05 < or = 0.03; n = 17; P < .0001). Additionally, IL-8 mRNA expression was strongly associated with the severity of portal inflammation (PI) (high PI vs. low PI, 0.22 +/- 0.14 vs. 0.05 +/- 0.04; P < .0001) and with the presence of bile duct lesions (0.29 +/- 0.15 vs. 0.11 +/- 0.1; P < .01). In contrast, hIRH mRNA expression was not associated with the total HAI, any components of the HAI, or bile duct inflammation or injury. These results suggest that hIRH, although having the -CXC-, alpha chemokine motif, and exhibiting in vivo and in vitro inflammatory activity as does IL-8, plays a different role from IL-8 in hepatic inflammation and injury. IL-8 expression is directly associated with inflammation in patients with chronic hepatitis C, while hIRH expression does not correlate with histopathological severity of inflammation.

Porphyria cutanea tarda, hepatitis C, and HFE gene mutations in North America

In some, but not all countries, porphyria cutanea tarda (PCT) has been associated with chronic infection with the hepatitis C virus (HCV). Recently, PCT has also been associated with mutations in the HFE gene that are associated with HLA-linked hereditary hemochromatosis. Until now, few studies of these associations have been reported from North America. The aims of this study were: 1) to assess the prevalence of HCV infection and HFE mutations in North American patients with PCT; 2) to compare demographic and laboratory features between those who are HCV-positive and HCV-negative; and 3) to study urinary porphyrin excretions in American HCV-positive patients without clinically manifest PCT. Clinical and laboratory data, including tests for HCV and urinary porphyrins, were collected from 70 unselected patients with typical PCT. Urinary porphyrins were also measured in 110 non-PCT patients with chronic hepatitis C. Mutational analyses of the HFE gene were performed in 26 PCT patients. Thirty-nine of 70 (56%) of the PCT patients had evidence of HCV infection. Thirty-two of 39 PCT patients with HCV were men, all of whom used alcohol. In contrast, 22 of 31 PCT patients without HCV infection were women, 12 of whom had taken estrogens. The HCV-positive group was more likely to have used illicit intravenous drugs (45% vs. 0%; P = 0.01), to have had several (>4) sex partners (48% vs. 13%; P = 0.005), and less likely to have no known risk factors for HCV infection (33% vs. 78%; P = 0.004). Total urinary porphyrin excretion was the same in the two groups, but those with HCV infection had a significantly lower percentage of uroporphyrin and higher percentages of hepta-and hexa-carboxy porphyrins in urine. Sixteen of 110 (15%) HCV-positive subjects without PCT had increased urinary porphyrins, but, unlike PCT, these were mainly coproporphyrin. Forty-two percent of PCT patients carried the C282Y mutation of HFE (15% homozygous), and another 31% carried the H63D mutation (8% homozygous). Thus, 73% of PCT patients had one of these mutations. The prevalence of HCV infection (56%) and mutations in the HFE gene (73%) are high among North American patients with PCT. Alcohol and estrogen use are important additional risk factors. All PCT patients should be tested for HCV infection and for HFE gene mutations. Although HCV infection is a trigger for PCT, preclinical PCT is rare in chronic HCV hepatitis C in the United States.

Mechanism of sodium arsenite-mediated induction of heme oxygenase-1 in hepatoma cells. Role of mitogen-activated protein kinases

Heme oxygenase-1 is an inducible enzyme that catalyzes heme degradation and has been proposed to play a role in protecting cells against oxidative stress-related injury. We investigated the induction of heme oxygenase-1 by the tumor promoter arsenite in a chicken hepatoma cell line, LMH. We identified a heme oxygenase-1 promoter-driven luciferase reporter construct that was highly and reproducibly expressed in response to sodium arsenite treatment. This construct was used to investigate the role of mitogen-activated protein (MAP) kinases in arsenite-mediated heme oxygenase-1 gene expression. In LMH cells, sodium arsenite, cadmium, and heat shock, but not heme, induced activity of the MAP kinases extracellular-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. To examine whether these MAP kinases were involved in mediating heme oxygenase-1 gene expression, we utilized constitutively activated and dominant negative components of the ERK, JNK, and p38 MAP kinase signaling pathways. Involvement of an AP-1 site in arsenite induction of heme oxygenase-1 gene expression was studied. We conclude that the MAP kinases ERK and p38 are involved in the induction of heme oxygenase-1, and that at least one AP-1 element (located -1576 base pairs upstream of the transcription start site) is involved in this response.

Diagnosis of porphyric syndromes: a practical approach in the era of molecular biology

For cost-effective diagnosis of porphyric syndromes, a logical stepwise approach is best. If neurovisceral features suggest an acute porphyric syndrome, a rapid screening test for urinary porphobilinogen should be performed. If clinical features suggest a cutaneous porphyria, then for solar urticaria and acute photosensitivity (suggesting protoporphyria) screening tests for increased erythrocytic porphyrins should be done; for vesiculobullous formation (suggesting porphyria cutanea tarda, hereditary coproporphyria, or variegate porphyria) a screening test for urinary porphyrins should be done. Positive screening tests should be confirmed with targeted quantitative testing. Enzymatic assays and DNA-based testing are not usually needed for rapid diagnosis or management of symptomatic subjects, but they are useful for kindred evaluation and genetic counseling.

Molecular cloning, characterization, and expression of the chicken heme oxygenase-1 gene in transfected primary cultures of chick embryo liver cells

Using chick heme oxygenase-1 (cHO-1) cDNA as a probe, three independent clones were identified from screening a lambda FixII chick genomic library. Genomic Southern blots using this cDNA probe or a cHO-1 5' specific probe showed that cHO-1 is a single-copy gene. Based on restriction enzyme analysis, Southern blots, polymerase chain reaction analysis and DNA sequencing, it was confirmed that the three overlapping clones isolated cover the entire cHO-1 gene, as well as approximately 10 kb of the flanking regions on both ends. As with mammalian HO-1x, cHO-1 has five exons and four introns. Computer analysis of the DNA sequence obtained identified consensus sequences corresponding to numerous transcription factor recognition elements. These include AP-1, AP-2, NF-kB, C/EBP, c-Myc and a metal-responding element identified in the promoter region, and two Sp-1 elements in intron 1. Transient expression studies in transfected primary cultures of chick embryo liver cells showed that a CAT reporter gene construct containing 2.8 kb of the cHO-1 promoter region responded to sodium arsenite, H2O2, transition metals and 12-0-tetradecanoylphorbol 13-acetate, but not to heme. Studies with deletion mutants, consisting of various lengths of the cHO-1 promoter region, indicated that there are two regions important for sodium arsenite induction, one located between residues -1642 and -1293, and the second located in the first 263 base pairs of the cHO-1 promoter. DNA binding studies by electrophoretic mobility shift assay showed that nuclear protein isolated from primary cultures of chick embryo liver cells bound to the oligonucleotide probe containing an AP-1 element identified at -1573 to -1580. In addition, such binding was increased by cobalt or sodium arsenite treatment.

Utility of hepatic iron index in American patients with hereditary hemochromatosis: a multicenter study

BACKGROUND & AIMS

A hepatic iron index (hepatic iron concentration divided by age) of more than 1.9 has been proposed as useful to identify patients with homozygous hereditary hemochromatosis (HHC). There are limited data on the diagnostic use of the hepatic iron index in patients with HHC in the United States. This study evaluated the hepatic iron index in the diagnosis of HHC in a multicenter U.S. study.

METHODS

Hepatic iron concentration was measured in 509 patients undergoing liver biopsy. The diagnosis of HHC was made using clinical, biochemical, and histopathologic criteria.

RESULTS

Fifty-five patients met criteria for HHC; hepatic iron index was > 1.9 in 51 of 55 (93%) patients with HHC but in none of 454 patients with other liver diseases; hepatic iron concentration was > 71 mumol/g dry weight in 54 of 55 patients with HHC but only 1 of the other 454 patients.

CONCLUSIONS

A hepatic iron index of > or = 1.9 can identify most U.S. patients with HHC but is < or = 1.9 in 7%. A "threshold" hepatic iron concentration of 71 mumol/g can almost always distinguish patients with HHC from patients with other liver diseases and may be a useful adjunct to the hepatic iron index in the diagnosis of HHC in the diverse U.S. population.

Inflammatory markers in chronic hepatitis C

To test the hypothesis that inflammation in hepatitis C follows mechanisms common to immune-activated pathways, the distributions of T and B cells, adhesion molecules and transforming growth factor-beta (TGF-beta) were assessed in liver biopsies with chronic inflammation due to hepatitis C (HCV, n = 8) and other causes (non-HCV, n = 10). Frozen sections were immunostained using primary antibodies to CD2, CD20, CD4, CD8, intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM)-1, HLA-DR, lymphocyte function-associated antigen (LFA)-1, and TGF-beta. Inflammatory cells positive for each immunophenotypic marker were counted, and positive staining for adhesion molecules, HLA-DR and TGF beta was graded in triads and lobules and compared in HCV and non-HCV biopsies. In all biopsies, T cells were more frequent than B cells, both in triads and lobules. CD20+, CD4+, CD8+ and LFA-1+ cells were increased in HCV compared to non-HCV biopsies. Portal lymphoid aggregates were present in 6 of 8 HCV biopsies and 3 of 10 non-HCV biopsies. Aggregates consisted of CD20+, CD4+, CD8+ and LFA-1+ cells, and ICAM-1 and VCAM-1 were increased. Sinusoidal lining cells in HCV biopsies and non-HCV biopsies with inflammation expressed HLA-DR, ICAM-1, and CD4. TGF-beta was increased in foci of necrosis. Inflammation in chronic HCV involves common immune-mediated cellular effector pathways and the inflammation in the portal triads represents aggregation of both T and B cells, mediated in part by upregulation of adhesion molecules on portal stromal cells; this is possibly in response to antigens draining from necroinflammatory foci in the lobules. TGF-beta is increased in active necroinflammatory foci, but not in portal lymphoid aggregates.

Therapy of hepatitis C: other options

Because current standard therapy of chronic hepatitis C with alpha interferon is less than ideal, numerous other approaches have been studied. Iron in the liver, particularly that found in vascular endothelial cells of portal tracts, has been associated with decreased responsiveness to alpha interferon therapy. Iron reduction alone, generally achieved by therapeutic phlebotomy, regularly has been associated with biochemical improvement (decrease in serum alanine aminotransferase), but not with virological improvement. Iron reduction has been reported to increase the therapeutic response to alpha interferon. Most studies of this combination have been conducted in patients who had not responded to interferon alone; in these patients, improved responsiveness has been observed in some, but not all studies. In patients not previously treated, iron reduction was found in a recent trial to improve the sustained biochemical and virological response rate from 5% to 29%. Hepatic iron and chronic hepatitis C increase oxidative stress in the liver and are associated with decreases in hepatic glutathione levels. In one report, administration of N-acetyl cysteine, a sulfhydryl donor, led to improved response to interferon in chronic hepatitis C. Several cytokines and immunomodulators have undergone limited study; perhaps the most promising of these is thymosin alpha-1. In one small study, amantadine was found to produce some response in patients who previously had failed to respond to interferon. Ursodiol improves serum aminotransferase levels in chronic hepatitis C but has no antiviral effect, nor has it been found to improve histologic abnormalities. The future of therapy of chronic hepatitis C will likely include measures to decrease oxidative stress and injury and multidrug combinations, including inhibitors of the hepatitis C viral protease and RNA polymerase.

Effects of new anticonvulsant medications on porphyrin synthesis in cultured liver cells: potential implications for patients with acute porphyria

Some patients with acute hereditary porphyrias have seizures and require anticonvulsant therapy, but many anticonvulsants induce exacerbations of the hepatic porphyrias. Recently, several new anticonvulsants have become available. Among these are gabapentin, vigabatrin, felbamate, lamotrigine, and tiagabine. Little is known about their potential for induction of porphyric attacks. We used a cell culture model of primary chicken embryo liver cells, which maintain intact heme synthesis and regulation, to study the effects of these new anticonvulsants on porphyrin accumulation. Treatment of the cells with deferoxamine (250 microM) led to a partial block in heme synthesis, simulating the conditions encountered in human beings with porphyria. Concomitant exposure of these cells to phenobarbital (2 mM) strongly induced accumulation of porphyrins, serving as a positive control in this model. Cells were treated for 20 hours with increasing doses (3.2 to 1,000 microM) of the newer anticonvulsants, with or without deferoxamine. For most of these anticonvulsants 5 to 100 microM is representative of the concentrations achieved in humans with therapeutic doses. Porphyrins were measured spectrofluorometrically as uro-, copro-, and protoporphyrins. Results were confirmed by high-pressure liquid chromatography. Neither vigabatrin nor gabapentin treatment, with or without deferoxamine, led to any increase in porphyrin accumulation. Similar doses of felbamate (with deferoxamine) led to a marked increase in (mainly proto-) porphyrin levels, qualitatively and quantitatively almost identical to the accumulation produced by phenobarbital. Lamotrigine or tiagabine (with deferoxamine) caused similar porphyrin accumulation. Tiagabine treatment up to 100 microM (with deferoxamine) also resulted in very high levels of predominantly proto-porphyrin. In contrast to the other anticonvulsants tested, tiagabine without deferoxamine led to mild porphyrin accumulation. In the presence of deferoxamine, phenobarbital, felbamate, lamotrigine, or tiagabine, but not gabapentin or vigabatrin, increased levels of the mRNA of ALA synthase, the first and rate-controlling enzyme of porphyrin synthesis. Such enzyme induction is a sine qua non for acute porphyric attacks. We conclude that neither vigabatrin nor gabapentin is porphyrogenic, whereas felbamate, lamotrigine, and, especially, tiagabine lead to much accumulation of porphyrins. The latter three anticonvulsants, therefore, may precipitate or exacerbate acute porphyric attacks in humans. We recommend use of vigabatrin or gabapentin, but not felbamate, lamotrigine, or tiagabine, in patients with acute porphyria and seizures.