Intrahepatic cholestasis of pregnancy.

Intrahepatic cholestasis of pregnancy is one of the primary disorders of the liver that adversely affects maternal well-being and fetal outcome. Early identification of this condition, careful interdisciplinary monitoring, and prompt delivery at fetal maturity can improve outcomes in the mother and child. Although the cause is unclear, IHCP probably arises from a genetic predisposition for increased sensitivity to estrogens and progestogens and altered membrane composition and expression of bile ducts, hepatocytes, and canalicular transport systems. As a result, the elevations in maternal levels of bile acids and their molar ratios seen in healthy pregnancy rise further in IHCP patients. Also, as the normal fetal-to-maternal transfer of bile acids across the trophoblast is impaired, the excess bile acids with abnormal profiles accumulate and are toxic to the fetus. The management of IHCP is dictated by the increased risks of fetal distress, spontaneous preterm delivery, and sudden death, as well as by alleviating pruritus in the mother. These risks to the fetus rise progressively to delivery, regardless of serum levels of bile acids and ALT. Close monitoring of these markers is essential but does not prevent sudden fetal distress and death. Provision should be made to induce labor as soon as fetal lung maturity has been established. Ursodeoxycholic acid is the only therapy that has proven effective, albeit in small studies, in alleviating pruritus and restoring towards normal the abnormal profiles of bile acids and sulfated steroids in serum and other body fluids. Ursodeoxycholic acid seems to have no obvious adverse effects on the fetus, but experience is insufficient to draw conclusions regarding teratogenicity and prevention of adverse outcomes.

Immunotherapy in the management of sepsis.

The pathophysiological effects of severe sepsis, septic shock and related syndromes result from tissues damaged by the uncontrolled production of the mediators of inflammation. Early deaths are related primarily to the acute effects of the systemic inflammatory response. Later deaths are related more closely to the consequences of multiple organ dysfunction. Monoclonal antibodies and other immunotherapies have been developed against bacterial products, cytokines and other mediators involved in this systemic inflammatory response. Immunotherapies may improve outcome in the critically ill with sepsis if used early and as part of the therapeutic regimen of antimicrobial agents and intensive care support.

Exclusion in liver by polymerase chain reaction of hepatitis B and C viruses in acute liver failure attributed to sporadic non-A, non-B hepatitis.

Hepatitis B and C viruses have been implicated in a few cases of acute liver failure attributed to sporadic (community acquired) non-A, non-B hepatitis, but reports are conflicting. We determined whether hepatitis B virus and hepatitis C virus were detectable in prospectively stored hepatectomies from seven British patients grafted for acute liver failure attributed to sporadic non-A, non-B hepatitis. For hepatitis B virus, we used nested polymerase chain reaction with primers to the core and surface regions. For hepatitis C virus, we used one round of reverse transcription polymerase chain reaction with primers to the 5' untranslated region and Southern hybridization using an internal oligonucleotide probe as well as nested PCR for the E1 region. Positive controls were native livers from two patients with unequivocal fulminant hepatitis B and from four patients with cirrhosis attributed to hepatitis C virus. Our negative findings suggest that, in the UK, acute liver failure attributed to sporadic non-A, non-B hepatitis most likely is caused by agent/s other than hepatitis B and C viruses.

Acute liver failure of unknown pathogenesis: the hidden agenda.

A major proportion of sporadic cases of ALF remain of uncertain cause (formerly termed NANB hepatitis). The application of sensitive molecular biology techniques such as PCR indicates that a few cases may be due to cryptic infections with one or more known hepatotropic agents, such as HBV and HCV. Evidence continues to accumulate to incriminate at least one potentially novel and transmissible agent (candidate hepatitis F). In ALF of unknown pathogenesis, survival without transplantation remains less than 20% despite recent improvements in medical management. Close study of recurrent hepatitis after grafting may provide further clues to the possible causes of ALF and the interaction between infectious agent and host. The continued pursuit of potential causes seems justified to allow stratification according to possible pathogeneses. This scientific approach should provide a rational basis for future therapeutic options.

Toga virus-like particles in acute liver failure attributed to sporadic non-A, non-B hepatitis and recurrence after liver transplantation.

Toga virus-like particles (typically 60-70 nm: enveloped with small surface spikes) were detected in the native hepatectomy specimens in 7 of 18 patients grafted for acute liver failure attributed to sporadic non-A, non-B hepatitis and in 2 patients grafted for fulminant hepatitis attributed to anti-epileptic drug hepatotoxicity. These particles were not detected in the hepatectomies from 12 other patients grafted for other causes of acute liver failure, 12 for various chronic liver diseases, and 2 histologically normal livers. Acute hepatic failure, characterized histologically by severe haemorrhagic necrosis, developed 7 days after grafting in 5 patients, all in the non-A, non-B group with toga virus-like particles in native liver. Similar virus-like particles were detected in all grafts and were in greater abundance than in the native livers. The agent may be novel because pre- and post-grafting sera were negative for antibodies against representative panels of arboviruses and in first and second generation antibody tests for hepatitis C virus.

Hepatitis A to G and beyond.

Recent advances in viral hepatitis reflect the progress of molecular biology. Their clinical applications may provide clues for future prevention.

Association of a precore genomic variant of hepatitis B virus with fulminant hepatitis.

A variant of hepatitis B virus has been described recently in HBsAg+ Mediterranean patients who lack HBeAg and who have an unusual and severe form of chronic hepatitis. This variant is unable to produce HBeAg because of the presence of a novel translational stop codon at the end of the precore region of the genome. By direct sequencing of DNA, generated by the polymerase chain reaction, we have evaluated the association between infection with this variant and the fulminant course of hepatitis B. Eighteen patients with fulminant hepatitis B were studied. Of the 15 cases from whose serum viral DNA could be sequenced, the variant was found in the admission sera of 8 of 9 HBeAg- patients but in none of 6 HBeAg+ patients who had fulminant hepatitis B. Patients harboring the variant progressed more rapidly into hepatic encephalopathy, but those infected with the variant strain alone had a greater likelihood of survival than those infected with the normal strain or a mixture. The mutant strain may emerge spontaneously during fulminant hepatitis as occurs in chronic hepatitis B infection during seroconversion from HBeAg to antibody. Alternately, and perhaps less commonly, patients may be infected with the variant ab initio.

Prognostic significance of pre-S2 antigen and antibody in fulminant hepatitis B. Evidence for heterogeneous serological responses.

Serial sera were collected prospectively and from early on in the clinical course of ten patients with fulminant hepatitis B. These were analysed for HBV DNA (dot-blot technique), HBsAg, HBeAg, pre-S2-Ag and their respective antibodies. Two patterns emerged in nine of the patients. The first and well-recognised pattern of rapid clearance of antigens and appearance of antibodies was seen in four patients, all of whom survived. The second pattern seen in five patients was one of persistence of HBsAg and pre-S2 antigen and failure to detect antibodies but only one patient survived. The first pattern may reflect a more rapid cessation of virus replication and this may favour liver cell regeneration and recovery. In contrast, the second pattern may indicate continuing virus replication and liver cell damage which could contribute to the high mortality in some patients with fulminant hepatitis B.

Impaired binding properties of thyroxine-binding globulin in hepatocellular carcinoma and chronic liver disease.

To determine the factors underlying the apparent reduction in binding ability of thyroxine-binding globulin in hepatocellular carcinoma, hormone-binding characteristics were further examined in patients with this disease and in control subjects. No differences in affinity constants with respect to triodothyronine or serum thyroxine-binding globulin from hepatocellular carcinoma, cirrhotic and normal subjects were found. The affinity for thyroxine was significantly reduced in hepatocellular carcinoma (0.41 +/- 0.13 x 10(10) mol-1) and cirrhotic (0.65 +/- 0.1 x 10(10) mol-1) patients compared with normal subjects (0.94 +/- 0.7 x 10(10) mol-1). Investigations carried out on liver tissue obtained from patients with hepatocellular carcinoma and chronic liver disease showed that thyroxine-binding globulin within tumor tissue was elevated and bound less exogenous tracer hormone compared with that obtained from nontumor tissue. Tumor-derived thyroxine-binding globulin with altered binding properties is, at least partly, responsible for the abnormal behavior of the serum protein in patients with hepatocellular carcinoma.

Cytoprotective effects of calcium channel blockers. Mechanisms and potential applications in hepatocellular injury.

Deregulation of calcium homeostasis is strongly implicated in the development of cellular injury, including in hepatocytes, and is thought to be the limiting step in transition to an irreversible stage. Calcium channel blockers appear to exert their cytoprotective effects through several mechanisms. These may involve blockade of L-(long-lasting)-type calcium channels, reduction of oxidative stress, antagonism at inflammatory mediator receptor sites and interaction at other intracellular sites. Studies relating to the liver are few but suggest that calcium channel blockers may have a role to play in limiting hepatocellular damage, especially those arising from exposure to a variety of toxic agents.

Delayed calcium channel blockade with diltiazem reduces paracetamol hepatotoxicity in mice.

1. Diltiazem (30 mg kg-1 body weight, intraperitoneally) given to mice 9 h after paracetamol (450 mg kg-1, orally) reduced liver damage, as judged by plasma aspartate aminotransferase activity (median 186, range 6-602 IU 1(-1), n = 18 vs 466, range 23-3872 IU 1(-1) in 18 saline-treated controls; P less than 0.05) with comparable reductions in mortality (14% vs 33%, respectively; NS). 2. Regenerative activity, as judged by mitotic figures in tissue removed at 30 h after paracetamol, was significantly higher in mice treated at 9 h with diltiazem (median 0.83 per high power field vs 0.1 in saline-treated controls; P less than 0.05). 3. Diltiazem administered earlier or later than 9 h showed reduced efficacy and in some cases potentiated toxicity, as did nifedipine (40 mg kg-1 in divided doses up to 9 h).

Detection of hepatitis B virus DNA sequences in liver in HBsAg seronegative patients with liver disease with and without anti-HBc antibodies.

Excluding studies from Brechot and co-workers, little support has been found for a role of the hepatitis B virus in the pathogenesis of HBsAg seronegative patients with predominantly chronic liver diseases, including primary liver cancer. In this study liver DNA from 59 predominantly British patients (four cases with paired biopsies, 6-12 months apart) with different, mostly chronic, liver diseases was analysed by molecular hybridization. All were seronegative for HBsAg and serum hepatitis B virus DNA (dot blot hybridization) and their liver diseases were believed to be unrelated to hepatitis B virus infection. Hepatitis B virus DNA was detected in liver of 11 (18.6 per cent) patients; nine had episomal (3.2 Kb) DNA and eight had higher molecular weight bands suggesting integrated forms. Six patients were also seronegative for anti-HBc. Patients of UK and non-UK origin were equally represented. Hepatitis B virus DNA was detected in serum of six of nine patients tested using the polymerase chain reaction. The detection of hepatitis B virus DNA in liver and in serum by this assay in a significant proportion of patients with chronic liver disease, hitherto unsuspected of being hepatitis B virus-related, suggests a possible role for this virus in low- as well as high-prevalence countries.

HBV-DNA sequences in tumor and nontumor tissue in a patient with the fibrolamellar variant of hepatocellular carcinoma.

One patient with the fibrolamellar variant of hepatocellular carcinoma was found to be seropositive for HBsAg and anti-HBe. DNA from tumor and nontumor areas of the liver was examined by molecular hybridization for hepatitis B virus DNA sequences. Undigested DNA from the tumor gave a high-molecular-weight smear, and restriction-enzyme analysis indicated a single instance of integration. Nontumor liver tissue was analyzed from three separate areas. Hepatitis B virus DNA was detected in two of these; restriction-enzyme digestion suggested they contained different sites of viral integration. As with the typical hepatitis B virus-related hepatocellular carcinoma, analysis of hepatitis B virus DNA from nontumorous liver yielded a different pattern of high-molecular-weight bands, indicating that the virus genome had integrated at different chromosomal locations than that seen in the tumor. The finding of integrated hepatitis B virus DNA, especially in tumorous but also in nontumorous liver, would be consistent with an oncogenic role for hepatitis B virus in certain instances of fibrolamellar tumors and in the more typical hepatitis B virus-related hepatocellular carcinoma.

Fulminant viral hepatitis.

In the United Kingdom and United States of America, fulminant viral hepatitis is due mainly to sporadic (non-parenteral) non-A, non-B hepatitis and hepatitis B whereas that caused by hepatitis A virus is very uncommon and by the herpes viruses remains rare. Recent advances in fulminant non-A, non-B hepatitis have come with the identification and cloning of a virus (27-34 nm) in the enteral variety (hepatitis E) which is prevalent in the Indian sub-continent, North Africa and elsewhere, especially in pregnant women. Virus-like particles (50-70 nm) with ultrastructural features similar to the togaviridae and flaviviridae have been identified in some patients with fulminant non-A, non-B hepatitis in the United Kingdom. The relation to hepatitis C virus, recently identified as a major cause of chronic post-transfusion (parenteral) non-A, non-B hepatitis, awaits serological analysis. The recent demonstration that persistence of active viral replication can occur in some cases of fulminant hepatitis types A and B using monoclonal antibody and molecular biology techniques challenges the classical views on the pathogenesis of these varieties of fulminant viral hepatitis.

Toga-like virus as a cause of fulminant hepatitis attributed to sporadic non-A, non-B.

Virus-like particles (60-70 nm) with spiked surfaces budding into cell vacuoles and rod-shaped inclusions were detected in nuclei of hepatocytes from a British patient transplanted for sporadic non-A, non-B fulminant hepatitis (NANB-FHF), probably contracted in Kenya. Identical particles were seen in two successive grafts (days 2 and 10) at regrafting for recurrent FHF. Ultrastructural features resembled those of the RNA-containing arbovirus, Rift Valley fever virus, but serological markers against a representative panel for arboviruses (Togaviruses) and transmission in mice proved negative. The particles shared features with the different arboviruses seen in the hepatectomy specimen of a second patient with NANB-FHF, and in both patients an insect vector was implicated in the clinical history. The particles were identical in size to those of a third patient with NANB-FHF, who had remained in the United Kingdom. These findings, together with the recent report of isolation of an RNA-containing virus resembling the Togaviridae, in parenteral NANB, suggest that several exotic virus-like agents resembling the arboviruses may be involved in the aetiology of NANB, including in the sporadic forms of FHF in the United Kingdom.