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.

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.

Antigen-specific T lymphocyte proliferation decreases over time in advanced chronic hepatitis C.

To evaluate T cell immunity in advanced liver disease, antigen-specific lymphoproliferative (LP) responses were prospectively studied in the context of the Hepatitis C Antiviral Long-term Treatment against Cirrhosis trial. Peripheral blood responses to hepatitis C virus (HCV), tetanus and Candida protein antigens were measured at baseline, month 12 (M12), M24, M36 and M48 in 186 patients randomized to either low-dose peginterferon-alfa-2a (PEG-IFN) only or observation. Liver histology was evaluated at baseline, M24 and M48. Patients with cirrhosis (Ishak 5-6) were less likely to have positive LP responses to HCV at baseline than patients with fibrosis (15%vs 29%, P = 0.03) and had lower levels of HCV c100 responses at baseline, M24 and M48 (P = 0.11, P = 0.05, P = 0.02, respectively). For 97 patients with complete longitudinal data, the frequency of positive LP responses to HCV, tetanus and Candida antigens declined over time (P < 0.003), and the slope of this decline was greater in the PEG-IFN treatment group than the observation group (P < 0.02). Lower levels of tetanus LP responses were associated with fibrosis progression and clinical outcomes (P = 0.009). Poorer CD4+ T cell proliferative function was associated with more advanced liver disease in chronic hepatitis C and may be further affected by long-term PEG-IFN treatment.

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.

Givosiran to treat acute porphyria.

Porphyrias are a family of rare diseases chiefly due to inborn errors of heme biosynthesis. The porphyrias are generally characterized either by the main site of overproduction of heme precursors (hepatic or erythropoietic) or the main clinical manifestations (acute or cutaneous). The regulation of 5- (or δ)-aminolevulinic acid synthase 1 (ALAS1) plays a key role in the pathway of normal hepatic heme synthesis, providing insight into the pathophysiologic mechanisms and potential therapeutic targets for the treatment of the porphyrias. Givosiran (Givlaari; Alnylam Pharmaceuticals) is an ALAS1-directed small interfering RNA (siRNA) which has been developed for the treatment of acute hepatic porphyria (AHP). It was first approved in 2019 by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with AHP, and it received also approval in the E.U. in 2020 for the treatment of AHP in adults and adolescents aged 12 years and older.

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.

Differential effects of metalloporphyrins on messenger RNA levels of delta-aminolevulinate synthase and heme oxygenase. Studies in cultured chick embryo liver cells.

The acute porphyrias in relapse are commonly treated with intravenous heme infusion to decrease the activity of delta-aminolevulinic acid synthase, normally the rate-controlling enzyme in heme biosynthesis. The biochemical effects of heme treatment are short-lived, probably due in part to heme-mediated induction of heme oxygenase, the rate-controlling enzyme for heme degradation. In this work, selected nonheme metalloporphyrins were screened for their ability to reduce delta-aminolevulinic acid synthase mRNA and induce heme oxygenase mRNA in chick embryo liver cell cultures. Of the metalloporphyrins tested, only zinc-mesoporphyrin reduced delta-aminolevulinic acid synthase mRNA without increasing heme oxygenase mRNA. The combination of zinc-mesoporphyrin and heme, at nanomolar concentrations, decreased delta-aminolevulinic acid synthase mRNA in a dose-dependent manner. The combination of zinc-mesoporphyrin (50 nM) and heme (200 nM) decreased the half-life of the mRNA for delta-aminolevulinic acid synthase from 5.2 to 2.5 h, while a similar decrease was produced by heme (10 microM) alone (2.2 h). The ability of zinc-mesoporphyrin to supplement the reduction of delta-aminolevulinic acid synthase mRNA by heme, in a process similar to that observed with heme alone, provides a rationale for further investigation of this compound for eventual use as a supplement to heme therapy of the acute porphyrias and perhaps other conditions in which heme may be of benefit.

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 catabolism in cultured hepatocytes: evidence that heme oxygenase is the predominant pathway and that a proportion of synthesized heme is converted rapidly to biliverdin.

Heme oxygenase has been considered to be involved in the predominant pathway of heme degradation in vivo. However, alternative pathways involving cytochrome P-450 reductase, and lipid peroxidation, have previously been demonstrated in vitro, and studies with cultured rat hepatocytes were interpreted to show a majority of endogenous hepatic heme breakdown by non-heme oxygenase pathways. To clarify the pathway of heme breakdown in hepatocytes and the role of heme oxygenase in this process, cultured hepatocytes were pre-labelled with 5-[5-14C]aminolevulinate [( 14C]ALA). Radioactivity in heme, carbon monoxide, and bile pigments was measured for 8-24 h after the removal of [14C]ALA. In cultured chick embryo hepatocytes, which lack biliverdin reductase, the rate of production of biliverdin IXa was closely similar to the rate of catabolism of exogenous heme and radioactivity in carbon monoxide and biliverdin IXa was similar to the loss of radioactivity from endogenous heme. These results support the conclusion that heme breakdown occurred predominantly, if not solely, by heme oxygenase. Also, no evidence of non-heme oxygenase pathways was found in the presence of tin protoporphyrin, an inhibitor of heme oxygenase or mephenytoin, an inducer of both cytochrome P-450 and heme oxygenase. Similarly, in untreated cultured rat hepatocytes, radioactivity in carbon monoxide corresponded with loss of radioactivity in endogenous heme. In other experiments with chick hepatocyte cultures, rates of heme synthesis and breakdown were measured, and data were fitted to various models of hepatic heme metabolism. The results observed were consistent only with models in which an appreciable fraction (control cells, 17%, mephenytoin treated cells, 41%) of the newly synthesized heme was degraded rapidly to biliverdin.

Synergistic induction of delta-aminolevulinate synthase by glutethimide and iron: relationship to the synergistic induction of heme oxygenase.

Relationships between activities of delta-aminolevulinate synthase and heme oxygenase, respectively the rate-limiting enzymes of heme biosynthesis and degradation, have been studied in chick embryo liver cell cultures following exposure of the cultures to glutethimide and iron, a combination known to produce a synergistic induction of both enzymes. In time-course experiments, synergistic induction of heme oxygenase activity by glutethimide and iron preceded that of delta-aminolevulinate synthase by 4 h. Effects of selective inhibitors of both heme synthesis and degradation have also been studied with respect to effects on delta-aminolevulinate synthase and heme oxygenase activities. The synergistic induction of heme oxygenase by glutethimide and iron appears to be dependent upon cellular heme synthesis because addition of inhibitors of heme biosynthesis, 4,6-dioxoheptanoic acid or N-methyl-mesoporphyrin abolishes this synergistic induction. Exposure of cultures to tin-mesoporphyrin, a potent inhibitor of heme oxygenase, prevented the synergistic induction of delta-aminolevulinate synthase produced by glutethimide and iron, or, when added after induction was already established, promptly halted any further induction. These results suggest that the level of activity of heme oxygenase can reciprocally modulate intracellular heme levels and thus activity of delta-aminolevulinate synthase.

Regulation of expression of the human heme oxygenase-1 gene in transfected chick embryo liver cell cultures.

Induction of heme oxygenase (HO) has been proposed as a protective cellular mechanism against oxidative damage. In previous work (Tyrrell et al., Carcinogenesis [1993] 14, 761-765), portions of the 5' promoter region of the human HO-1 gene linked to the reporter gene chloramphenicol acetyl transferase (CAT), had been transiently expressed in HeLa cells. To extend the study of human HO gene expression into primary liver cells, these reporter gene fusion constructs, containing 121 or 1416 base pairs of the untranscribed 5'-upstream sequences of the human HO-1 gene, were used along with pSV beta-Gal plasmid to dually transfect primary cultures of chick embryo liver cells (CELC). The transfected cells were treated with selected metals, heme, phorbol ester, and chemical agents that produce oxidative stress (H2O2 or sodium arsenite). Reporter gene activities were measured 18-20 h later. Our major findings are: (1) these HO-CAT constructs were expressed in CELC; (2) unlike HeLa cells, the expression of CAT was detected in CELC without the need for the SV40 enhancer; (3) sodium arsenite and cobalt chloride induced the expression of the HO-CAT constructs whereas heme had no effect on or decreased CAT expression for all of the transfected constructs; (4) study of endogenous chick HO-1 gene expression in CELC showed that HO-1 responded to sodium arsenite treatment in a dose-dependent fashion, and the response was rapid and transient. We conclude that, in chick liver cell cultures, induction of the HO-1 gene by heme is fundamentally different from that produced by transition metals or sodium arsenite. Furthermore, the results suggest that expression of the HO-1 gene is highly conserved across species.

Induction of heme oxygenase-1 in LMH cells. Comparison of LMH cells to primary cultures of chick embryo liver cells.

Heme oxygenase catalyzes the degradation of heme into biliverdin, carbon monoxide, and iron. Two forms of this enzyme, heme oxygenase-1 and -2, have been identified; only heme oxygenase-1 is subject to induction by heme, metal ions, and other chemical and physical perturbations (e.g. drugs, oxidants, and heat shock). Primary chick embryo liver cells are widely used for the study of heme metabolism because of their ease of preparation, low cost, and high degree of similarity to human heme metabolism. Nonetheless, this system has some limitations: new cultures must be prepared every week; the resulting cell populations are non-homogeneous; and cells are short-lived, limiting the feasible duration of time course and transfection studies. LMH cells are the first chicken hepatoma cell line to be established. The aim of this study was to characterize the regulation of heme oxygenase-1 in LMH cells, and to compare this regulation to that previously described in primary chick embryo liver cells. The induction of heme oxygenase-1 was assessed by measuring changes in mRNA levels or enzyme activities in response to several treatments, including heme, heavy metals, sodium arsenite, and heat shock, which have been shown to increase the expression of heme oxygenase. Similarities were observed with respect to regulation of heme oxygenase-1 expression in primary hepatocytes and LMH cells. We report the first measurable heat shock response of heme oxygenase-1 in CELC or LMH cells; and show that LMH cells are a useful model for the study of heme oxygenase-1 regulation.

Multiple chemical sensitivity syndrome and porphyria. A note of caution and concern.

Growing numbers of patients suffering from many symptoms believe that they have a condition called multiple chemical sensitivity syndrome (MCSS). It has been suggested that this syndrome can be triggered by exposure to any of a large and usually incompletely defined number of natural and synthetic chemical substances. Major medical organizations, including the National Research Council and the American Medical Association, have not recognized MCSS as a clinical syndrome because of a lack of valid, well-controlled studies defining it and establishing pathogenesis or origin. Lately, some have proposed that many patients with MCSS suffer from hereditary coproporphyria. However, this purported association is based chiefly on results from a single reference laboratory of a fundamentally flawed assay for erythrocyte coproporphyrinogen oxidase. Although patients with MCSS may, at times, have modest increases in urinary coproporphyrin excretion, this is a common finding found in many asymptomatic subjects or patients with diverse other conditions (eg, diabetes mellitus, heavy alcohol use, liver disease, and many kinds of anemia). Such secondary coproporphyrinuria does not indicate the existence of coproporphyria. To our knowledge, there is no scientifically valid evidence to support an association between MCSS and coproporphyria, nor is there any unifying hypothesis for rationally linking these 2 disorders.

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.

Mixed cryoglobulinemia in chronic hepatitis C infection. A clinicopathologic analysis of 10 cases and review of recent literature.

We present 10 cases of mixed cryoglobulinemia in patients infected with hepatitis C, including pertinent clinical, serologic, and pathological data. The findings attributable to MC appear to be similar in patients who are HCV-infected as in those with unknown HCV status. The prevalence of MC in HCV-infected patients appears to be lower in our region (13%) than in southern Europe (50-90%) although some of this difference is due to our requirement that patients included in our study have a cryocrit of at least 5%. In our patients, cryoglobulins were shown to be deposited in skin and kidney, but not in liver. The mechanisms by which HCV and MC are related remain uncertain. Although we and others have evidence for enrichment of HCV RNA in the cryoprecipitates of some patients, this was not always the case, and it is not yet clear that this finding is of fundamental pathogenic importance. Finally, it appears that some patients with HCV and MC may have a beneficial clinical response of vasculitic symptoms to therapy with alpha-interferon, as well as to glucocorticoids or other immunosuppressants. In our group, no predictors were apparent to distinguish responders from nonresponders before treatment. Similarly, the duration of response remains to be determined.

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.

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.

Regulation of metallothionein gene expression. Studies in transfected primary cultures of chick embryo liver cells.

To study the regulation of expression of the metallothionein gene in normal liver cells, we transfected chick embryo liver cells in primary cultures with constructs containing luciferase or chloramphenicol acetyl transferase (as reporter genes) under the control of differing lengths of the 5'-promoter region of the chick metallothionein gene (containing 30, 122, 190, or 623 base pairs upstream of the transcriptional start site). We controlled for efficiency of transfection by co-transfections with a plasmid containing a bacterial beta-galactosidase gene under the control of the SV 40 promoter and enhancer. Treatment of the transfected cells with transition metallic ions (cadmium, cobalt, and zinc) or sodium arsenite produced increases in activities of luciferase or chloramphenicol acetyl transferase, relative to beta-galactosidase, and this activity mapped to the first 122 base pairs of the promoter. Although heme has recently been reported to induce the endogenous metallothionein gene in chick embryo liver cells, 10-50 microM heme did not increase reporter gene activities in transfected cells. Nevertheless, the heme-dependent induction of endogenous heme oxygenase-1 in these cells was normal. We conclude that the heme-dependent induction of the liver metallothionein gene depends upon DNA region(s) outside the regulatory region of the chick metallothionein gene studied here and that elements within the first 122 base pairs of the metallothionein promoter are sufficient to confer responsiveness to transition metals or sodium arsenite.

Severe liver injury due to phenelzine with unique hepatic deposition of extracellular material.

Severe acute and chronic hepatic damage occurred in a white man who had taken phenelzine sulfate (Nardil) 45 mg daily for 70 days. Liver biopsy showed a mixed hepatitic and cholestatic pattern with extracellular deposition of a unique homogeneous collagenous substance. Portal cirrhosis developed and has persisted. The patient was found to have a "rapid acetylator phenotype" and high rate of metabolism of antipyrine. These innate factors may have predisposed to hepatic injury due to phenelzine.

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.