Fifty years of impact on liver pathology: a history of the Gnomes

Professional societies play a major role in medicine and science. The societies tend to be large with well-developed administrative structures. An additional model, however, is based on small groups of experts who meet regularly in an egalitarian model in order to discuss disease-specific scientific and medical problems. In order to illustrate the effectiveness of this model, the history and practices are examined of a long-standing successful example, the International Liver Pathology Group, better known as the Gnomes. The history shows that groups such as the Gnomes offer a number of important benefits not available in larger societies and nurturing such groups advances science and medicine in meaningful ways. The success of the Gnomes' approach provides a road map for future small scientific groups.

Propriétés coagulantes d’hémolysats erythrocytaires

1. L’hémolysat érythrocytaire possède une activité coagulante, démontrée dans les tests globaux de la coagulation.

2. Cette activité ne peut pas être expliquée par une contamination plaquet-taire des préparations d’hémolysat.

3. L’hémolysat ne contient pas de thrombine, de prothrombine, facteur VII, facteur anti-hémophilique, ni de facteur IX. Il est par contre légèrement contaminé par le facteur V, probablement d’origine plasmatique.

4. L’activité de l’hémolysat est située surtout dans la première phase de la coagulation sanguine, c. à d. la formation de la thromboplastine. Son rôle est à peu près identique à celui du facteur thromboplastique des thrombocytes.

5. L’hémolysat préparé à partir du sang du cordon ombilical montre une activité très prononcée, qui n’est pas retrouvée dans le test de la formation de la thromboplastine.

6. Les hémolysats préparés du sang de différents animaux sont les plus actifs sur les plasmas de la même espèce.

7. Les hémolysats préparés du sang d’hémophiles du type A ou B, de malades atteints d’anémies hémolytiques, et de malades traités aux dérivés coumariniques ont une activité coagulante normale.

Embryology of extra- and intrahepatic bile ducts, the ductal plate

In the human embryo, the first anlage of the bile ducts and the liver is the hepatic diverticulum or liver bud. For up to 8 weeks of gestation, the extrahepatic biliary tree develops through lengthening of the caudal part of the hepatic diverticulum. This structure is patent from the beginning and remains patent and in continuity with the developing liver at all stages. The hepatic duct (ductus hepaticus) develops from the cranial part (pars hepatica) of the hepatic diverticulum. The distal portions of the right and left hepatic ducts develop from the extrahepatic ducts and are clearly defined tubular structures by 12 weeks of gestation. The proximal portions of the main hilar ducts derive from the first intrahepatic ductal plates. The extrahepatic bile ducts and the developing intrahepatic biliary tree maintain luminal continuity from the very start of organogenesis throughout further development, contradicting a previous study in the mouse suggesting that the extrahepatic bile duct system develops independently from the intrahepatic biliary tree and that the systems are initially discontinuous but join up later. The normal development of intrahepatic bile ducts requires finely timed and precisely tuned epithelial-mesenchymal interactions, which proceed from the hilum of the liver toward its periphery along the branches of the developing portal vein. Lack of remodeling of the ductal plate results in the persistence of an excess of embryonic bile duct structures remaining in their primitive ductal plate configuration. This abnormality has been termed the ductal plate malformation.

The clinicopathological and prognostic relevance of cytokeratin 7 and 19 expression in hepatocellular carcinoma. A possible progenitor cell origin

AIMS

Cytokeratin (CK) 7 and CK19 expression, present in hepatic progenitor cells (HPCs) and in cholangiocytes but not in normal hepatocytes, has been reported in some hepatocellular carcinomas (HCCs); however, the incidence and relevance of this expression in HCC in Caucasians is not known. Therefore, our aim was to study the occurrence and clinicopathological characteristics of HCC expressing CK7 and/or CK19 in 109 Caucasian patients.

METHODS AND RESULTS

The expression of hepatocellular differentiation markers (Hepar, canalicular polyclonal carcinoembryonic antigen), biliary/progenitor cell markers (CK7, CK19), alpha-fetoprotein (AFP), p53 and beta-catenin in HCC was semiquantitatively assessed by immunohistochemistry. Of 109 HCCs, 78 were CK7-/CK19- (72%), 13 CK7+/CK19- (12%), seven CK7-/CK19+ (6%), 11 CK7+/CK19+ (10%). CK19 expression was significantly associated with elevated serum AFP (400 ng/ml) (P = 0.023), tumour AFP expression (P < 0.0001), presence in serum of anti-hepatitis B core (P = 0.016), less fibrosis in non-neoplastic parenchyma (P = 0.009) and less nuclear beta-catenin expression (P = 0.021). CK7 expression was significantly associated with elevated serum bilirubin (> 2 mg/dl) (P = 0.0005) and less nuclear beta-catenin expression (P = 0.003). HCC expressing CK19 had a higher rate of recurrence (P = 0.009, hazard ratio 12.5, n = 31) after liver transplantation compared with CK19- tumours.

CONCLUSIONS

In our series, 28% of HCCs contained cells expressing CK7 and/or CK19. They potentially derive from HPCs. The higher recurrence rate of CK19+ HCC after transplantation suggests a worse prognosis for these HCCs compared with CK19- HCC.

Preneoplastic lesions in human hepatocarcinogenesis

The early stages of hepatocarcinogenesis in human chronic liver diseases are characterized by the emergence of preneoplastic lesions of which some will eventually develop into hepatocellular carcinoma (HCC). Basic studies on the genetic and epigenetic alterations of these preneoplastic lesions may eventually lead to new therapeutic strategies. Clinicopathological studies are also important in order to determine optimal management of patients with a preneoplastic lesion. This article aims to provide a comprehensive review of the current concepts of preneoplastic lesion in chronic liver diseases. The microscopical small-cell dysplastic focus is the smallest morphologically recognizable precursor lesion of HCC and therefore is a logical target of study to elucidate the earliest events in hepatocarcinogenesis. In contrast, large-cell dysplasia is not a precursor lesion, but appears to be of clinical value because of its good predictive value for development of HCC. Dysplastic nodules (DNs) are macroscopically recognizable precursor lesions of HCC and high-grade DNs (HGDNs) have a risk of malignant transformation. Detection of DNs and correct differentiation from small HCC (<2 cm) is sometimes difficult, especially when only imaging techniques are used. Additional clinicopathological studies on identification and optimal treatment of DNs are necessary. Molecular studies on HGDNs and small HCCs may yield much information on the genetic mechanisms involved in the transition from severe dysplasia to early malignancy. In contrast, currently available data indicate that (large) regenerative nodules do not represent a distinct step in hepatocarcinogenesis. Animal models will be helpful in the further unravelling of human HCC development, provided that studies are performed on models that are good representatives of human hepatocarcinogenesis. We propose three criteria by which good mimickers can be identified.

Long-term benefit of interferon alpha therapy of chronic hepatitis D: regression of advanced hepatic fibrosis

BACKGROUND & AIMS

Little is known about the long-term effects of interferon alpha on clinical outcome and survival of patients with chronic hepatitis D.

METHODS

Thirty-six patients with chronic hepatitis D who participated in a randomized controlled trial of a 48-week course of high (9 million units) or low (3 million units) doses of interferon alpha or no treatment were followed for an additional 2 to 14 years.

RESULTS

Long-term survival was significantly longer in the high-dose group than in untreated controls (P = 0.003) or in the low-dose group (P = 0.019) but did not differ between patients treated with 3 million units and controls. Among surviving patients at 12 years of follow-up, a biochemical response was present in 7 of 12 treated with 9 million units, in 2 of 4 who received 3 million units, and in none of 3 controls. Long-term alanine aminotransferase (ALT) normalization correlated with improved hepatic function and loss of IgM antibody to hepatitis delta antigen (anti-HD). Patients in the high-dose group had a sustained decrease in HDV replication (P = 0.008), leading to clearance of HDV RNA and, eventually, hepatitis B virus (HBV) in some patients, as well as a dramatic improvement in liver histology with respect to activity grade (P = 0.0004) and fibrosis stage (P = 0.007). Strikingly, we documented an absence of fibrosis in the final biopsy of 4 patients with a long-term biochemical response and an initial diagnosis of active cirrhosis.

CONCLUSIONS

High doses of interferon alpha-2a significantly improved the long-term clinical outcome and survival of patients with chronic hepatitis D, even though the majority had active cirrhosis before the onset of therapy.

Nomenclature of the finer branches of the biliary tree: canals, ductules, and ductular reactions in human livers

The work of liver stem cell biologists, largely carried out in rodent models, has now started to manifest in human investigations and applications. We can now recognize complex regenerative processes in tissue specimens that had only been suspected for decades, but we also struggle to describe what we see in human tissues in a way that takes into account the findings from the animal investigations, using a language derived from species not, in fact, so much like our own. This international group of liver pathologists and hepatologists, most of whom are actively engaged in both clinical work and scientific research, seeks to arrive at a consensus on nomenclature for normal human livers and human reactive lesions that can facilitate more rapid advancement of our field.

A pilot study of therapeutic vaccination with envelope protein E1 in 35 patients with chronic hepatitis C

New treatments are needed for chronic hepatitis C patients in whom viral clearance cannot be achieved. Thirty-five chronic hepatitis C patients (genotype 1) were randomized to receive 20 mug of recombinant HCV E1 (E1) (n = 26) or placebo (n = 9) intramuscularly at weeks 0, 4, 8, 12, and 24. Thirty-four then received open-label E1 vaccine at weeks 50, 53, 56, 59, 62, and 65. Twenty-four patients (12 men, 12 women; mean age, 52 y; 18 interferon-based treatment failures; mean baseline alanine aminotransferase [ALT] level, 118 IU/L) underwent a biopsy before and after 2 courses of E1, 17 months later. Liver histology was scored by 2 blinded pathologists according to the Ishak and Metavir systems. Postinjection reactions were similar to placebo (alum only). Nine of 24 patients (38%) had improvement of 2 points or more, 10 (41%) remained stable, and 5 (21%) showed worsening in total Ishak score. Nine patients (38%) improved both on Ishak and Metavir fibrosis scores. Plasma HCV-RNA levels remained unchanged, whereas ALT levels showed a trend toward a decrease during treatment. All but 3 patients developed a significant de novo E1-specific T-cell response. The increase in anti-E1 antibody levels correlated with the decrease in total Ishak score and with the relative decreases in both Ishak fibrosis score and ALT level (all P < or =.01). In conclusion, E1 therapeutic vaccination is well tolerated and the observed effects warrant further study.

Hepatic immunohistochemical staining with a monoclonal antibody against HCV-E2 to evaluate antiviral therapy and reinfection of liver grafts in hepatitis C viral infection

BACKGROUND/AIMS

A simple and reproducible hepatic immunohistochemical staining (IHS) for hepatitis C virus (HCV) is not available. We aimed to validate hepatic IHS with monoclonal antibody (Mab) IG222, directed against the HCV-envelope 2 (E2) protein.

METHODS

A three-step indirect immunoperoxidase method was used for frozen sections and a two-step indirect EnVision technique was used for paraffin-embedded sections.

RESULTS

Naturally or in vitro HCV infected primary human hepatocytes were immunoreactive to HCV-E2. In the patient study (n=253), IHS had a sensitivity of 96% and a specificity of 91%. Six patients who showed positivity in the liver with Mab IG222, but remained anti-HCV and HCV-RNA negative, had hepatitis C-like changes in their liver biopsy. In one patient HCV-RNA could be detected in the liver biopsy. We confirmed early graft reinfection in patients transplanted for HCV-related disease (34 patients with serial biopsies). Treatment for acute cellular rejection with steroids was associated with an increase in staining intensity. In nine patients with clearance of HCV-RNA during antiviral therapy, seven achieved negativation of immunoreactivity and two a marked reduction.

CONCLUSIONS

The IHS with Mab IG222 is an accurate tool for diagnosis and clinical management of chronic hepatitis C.

Liver pathology and hepatocarcinogenesis in a long-term mouse model of erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disease of haem synthesis caused by a mutation in one of the alleles of the enzyme ferrochelatase. This mutation leads to partial deficiency of the enzyme, resulting in increased concentrations of protoporphyrin (PP) in blood, liver, and faeces. Five to ten per cent of patients with EPP develop severe liver disease characterized by the presence of PP deposits. This study used histochemistry and immunohistochemistry to investigate the histopathological features present in the livers of 44 mice with a heterozygous or homozygous point mutation in the ferrochelatase gene (fch/+ and fch/fch mice, respectively). Some fch/+ mouse livers showed mixed steatosis and large cell dysplasia. The livers of fch/fch mice showed periportal or septal fibrosis accompanied by an atypical ductular reaction. These findings suggest that the obstruction and damage of a proportion of large and small bile ducts by PP deposits cause an accumulation of PP in the parenchyma, which leads to damage and loss of hepatocytes due to the toxic effects of PP. The classical stages of hepatocarcinogenesis were observed and hepatic progenitor cells appear to be involved in this process. PP acts as the promoting agent and is probably also the initiating agent.

Ultrastructural visualization of hepatitis C virus components in human and primate liver biopsies

BACKGROUND/AIMS

Molecular and structural studies of hepatitis C virus (HCV) replication and infection have been performed on cultured cells and on serum of infected patients. No conclusive studies were conducted yet on human liver biopsies. This paper describes the ultrastructural findings of hepatitis C virus components in liver biopsies.

METHODS

Liver specimens from acutely and chronically HCV-infected chimpanzees (five each) and 29 chronic hepatitis C patients were studied. Diagnosis of HCV infection was based on clinical, serological, light microscopic and immunohistochemical data and on HCV RNA polymerase chain reaction.

RESULTS

In HCV-infected chimpanzees, tubular aggregates were observed in the cytoplasm of a significant number of hepatocytes and proven by immuno-electron microscopy to contain HCV-E2 viral envelope material. Identical tubular aggregates were seen in hepatocytes of chronic HCV-infected patients, although in smaller quantity and less frequently. A few single enveloped virus-like particles of 50-60 nm in diameter were seen for the first time in the hyaloplasm of hepatocytes of HCV-infected chimpanzees and patients.

CONCLUSIONS

For the first time, HCV envelope material was ultrastructurally identified in hepatocytes of HCV-infected chimpanzees and patients. Virus-like particles, although strongly suggestive for HCV, failed final confirmation at least by routinely used methods.

In vivo gene transfer of endothelial nitric oxide synthase decreases portal pressure in anaesthetised carbon tetrachloride cirrhotic rats

BACKGROUND

Portal hypertension in cirrhosis results from enhanced intrahepatic resistance to an augmented inflow. The former is partly due to an imbalance between intrahepatic vasoconstriction and vasodilatation. Enhanced endothelin-1 and decreased activity of hepatic constitutive endothelial nitric oxide synthase (NOS 3) was reported in carbon tetrachloride (CCl(4)) cirrhotic rat liver.

AIMS

To study whether an increase in hepatic NOS 3 could be obtained in the CCl(4) cirrhotic rat liver by in vivo cDNA transfer and to investigate a possible effect on portal pressure.

METHODS

Hepatic NOS 3 immunohistochemistry and western blotting were used to measure the amount of NOS 3 protein. Recombinant adenovirus, carrying cDNA encoding human NOS 3, was injected into the portal vein of CCl(4) cirrhotic rats. Cirrhotic controls received carrier buffer, naked adenovirus, or adenovirus carrying the lac Z gene.

RESULTS

NOS 3 immunoreactivity and amount of protein (western blotting) were significantly decreased in CCl(4) cirrhotic livers. Following cDNA transfer, NOS 3 expression and the amount of protein were partially restored. Portal pressure was 11.4 (1.6) mm Hg in untreated cirrhotic (n=9) and 11.8 (0.6) in lac Z transfected (n=4) cirrhotic rats but was reduced to 7.8 (1.0) mm Hg (n=9) five days after NOS 3 cDNA transfer. No changes were observed in systemic haemodynamics, in liver tests or urinary nitrates, or in NOS 3 expression in lung or kidney, indicating a highly selective transfer.

CONCLUSIONS

NOS 3 cDNA transfer to cirrhotic rat liver is feasible and the increase in hepatic NOS 3 leads to a marked decrease in portal hypertension without systemic effects. These data indicate a major haemodynamic role of intrahepatic NOS 3 in the pathogenesis of portal hypertension in CCl(4) cirrhosis.

Focal lesions in cirrhotic explant livers: pathological evaluation and accuracy of pretransplantation imaging examinations

Imaging detection and diagnosis of hepatocellular carcinomas (HCCs) and dysplastic nodules (DNs) in cirrhotic patients is important because the number, size, and type of focal lesions strongly influence patient management. Focal lesions detected by imaging examinations during pretransplantation evaluation were correlated with focal lesions detected during detailed pathological examination of 49 cirrhotic explant livers. Within 6 months before transplantation, color Doppler ultrasonography (US), contrast-enhanced computed tomography (CT), and magnetic resonance (MR) imaging were performed in 94%, 33%, and 55% of patients, respectively. In 2% to 8% of patients, different types of benign focal lesions were present, and a considerable proportion was interpreted as (pre)malignant on imaging examination. US detected only the largest HCCs (patient sensitivity, 40%; specificity, 100%) and no DNs. On a per-patient basis, contrast-enhanced CT and MR imaging had poor sensitivity (20% and 27%, respectively) and good specificity (100% and 94%, respectively) for DNs. Patient sensitivity and specificity of both techniques for HCC were reasonable (50% for CT, 70% for MR imaging) and good (79% for CT, 82% for MR imaging), respectively. Neither technique was able to detect smaller (pre)malignant lesions. As a consequence, 10% of patients underwent transplantation, although they exceeded the tumor number limit. Currently used imaging techniques cannot correctly determine the exact tumor burden in some cirrhotic patients. Regular contrast-enhanced MR examination of cirrhotic patients waiting for liver transplantation is the best tool for the early detection of (pre)malignant lesions.

The vagal nerve stimulates activation of the hepatic progenitor cell compartment via muscarinic acetylcholine receptor type 3

In the rat the hepatic branch of the nervus vagus stimulates proliferation of hepatocytes after partial hepatectomy and growth of bile duct epithelial cells after bile duct ligation. We studied the effect of hepatic vagotomy on the activation of the hepatic progenitor cell compartment in human and rat liver. The number of hepatic progenitor cells and atypical reactive ductular cells in transplanted (denervated) human livers with hepatitis was significantly lower than in innervated matched control livers and the number of oval cells in vagotomized rat livers with galactosamine hepatitis was significantly lower than in livers of sham-operated rats with galactosamine hepatitis. The expression of muscarinic acetylcholine receptors (M1-M5 receptor) was studied by immunohistochemistry and reverse transcriptase-polymerase chain reaction. In human liver, immunoreactivity for M3 receptor was observed in hepatic progenitor cells, atypical reactive ductules, intermediate hepatocyte-like cells, and bile duct epithelial cells. mRNA for the M1-M3 and the M5 receptor, but not the M4 receptor, was detected in human liver homogenates. In conclusion, the hepatic vagus branch stimulates activation of the hepatic progenitor cell compartment in diseased liver, most likely through binding of acetylcholine to the M3 receptor expressed on these cells. These findings may be of clinical importance for patients with a transplant liver.

The correlation between portal myofibroblasts and development of intrahepatic bile ducts and arterial branches in human liver

BACKGROUND/AIMS

The development of the intrahepatic bile ducts most likely requires interactions between epithelial and mesenchymal cells. In view of the epithelial-mesenchymal interactions between portal myofibroblasts (pMFs) and biliary epithelial cells in adult diseases of the bile ducts, we investigated the presence and function of pMFs during the development of intrahepatic bile ducts, as well as the development of intrahepatic branches of the hepatic artery.

METHODS

We performed haematoxylin-eosin-stainings and immunohistochemistry for alpha-smooth-muscle actin, cytokeratin 19 and vimentin on serial sections of 45 fetal and postnatal liver biopsies.

RESULTS

The mesenchyme of portal tracts in the ductal plate stage devoid of a hepatic artery branch, contained numerous and diffusely scattered pMFs. Portal tracts with a hepatic artery branch were always larger than those without and showed a decreasing number of pMFs. In the remodeling stage, all portal tracts contained a hepatic artery branch, and pMFs were restricted to the periductal mesenchyme. These periductal pMFs disappeared after full incorporation of the bile duct.

CONCLUSION

Our findings strongly suggest interactions between pMFs and epithelial cells of the developing bile ducts. The development of the intrahepatic arterial branches always precedes the incorporation of the tubular segments of the ductal plate.

Hepatic stellate cell/myofibroblast subpopulations in fibrotic human and rat livers

BACKGROUND/AIMS

Hepatic stellate cells (HSC) are commonly considered the precursor population of septal myofibroblasts (MF) in cirrhosis. We studied the distribution and expression profile of mesenchymal (myo)fibroblast-like populations in fibrotic and cirrhotic liver, in an attempt to elucidate their possible interrelationships.

METHODS

Fibrotic/cirrhotic livers (from 22 human explants and from two rat models: carbon tetrachloride intoxication, bile duct-ligation) were studied by means of immunohistochemistry (single and double immunostaining) with antibodies raised against desmin, alpha-smooth muscle actin (alpha SMA), glial fibrillary acidic protein (GFAP), neural-cell adhesion molecule (N-CAM), synaptophysin, neurotrophins, neurotrophin receptors and alpha B-crystallin (ABCRYS).

RESULTS

Septal MF showed the same expression profile as portal MF, in human and rat, being alpha SMA/ABCRYS/brain-derived nerve growth factor/GFAP-expression, with additional N-CAM- and desmin-expression in rat portal/septal MF. Perisinusoidally located HSC stained with all tested markers, MF at the septal/parenchymal interface showed an expression profile, intermediate between the profiles of HSC and portal/septal MF.

CONCLUSIONS

In advanced fibrosis and in cirrhosis, regardless of cause or species, three distinct mesenchymal (myo)fibroblast-like liver cell subpopulations can be discerned: portal/septal MF, interface MF and perisinusoidally located HSC. The fact that septal MF share more characteristics with portal MF than with HSC might suggest descent.

Hepatic progenitor cells in hepatocellular adenomas

Hepatocellular adenoma is a benign tumor of the liver that has a small but not negligible risk of malignant transformation into hepatocellular carcinoma. In analogy with the established role of oval cells in hepatocarcinogenesis in rodent models, human hepatic progenitor cells may have a function in the development of liver tumors. To investigate this issue, we performed immunohistochemistry on biopsies of 10 consecutively resected hepatocellular adenomas using markers for hepatic progenitor cells. Sections of paraffin-embedded and frozen biopsies were stained using antibodies against cytokeratins 7, 8, 18, and 19, chromogranin-A, OV-6, and neural cell adhesion molecule. Hepatic progenitor cells were observed in five of 10 hepatocellular adenomas. These five tumors also contained cells with an immunohistochemical phenotype intermediate between hepatic progenitor cells and hepatocytes. Hepatic progenitor cells and intermediate hepatocyte-like cells were scattered throughout the tumors with a density that varied from area to area. Ultrastructural examination confirmed the presence of hepatic progenitor cells. Our study shows that hepatic progenitor cells are present in a considerable proportion of hepatocellular adenomas, supporting the hypothesis that human hepatic progenitor cells can play a role in the development of hepatocellular tumors.

Expression of neural cell adhesion molecule in human liver development and in congenital and acquired liver diseases

In the liver, neural cell adhesion molecule (NCAM) is a marker of immature cells committed to the biliary lineage and is expressed by reactive bile ductules in human liver diseases. We investigated the possible role of NCAM in the development of intrahepatic bile ducts and aimed at determining whether immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases. Therefore, we performed immunohistochemistry for NCAM and bile duct cell markers cytokeratin 7 and cytokeratin 19 on frozen sections of 85 liver specimens taken from 14 fetuses, 10 donor livers, 18 patients with congenital liver diseases characterized by ductal plate malformations (DPMs), and 43 cirrhotic explant livers. Duplicated ductal plates and incorporating bile ducts during development showed a patchy immunoreactivity for NCAM, while DPMs were continuously positive for NCAM. Bile ducts showing complete or patchy immunoreactivity for NCAM were found in cirrhotic livers, with higher frequency in biliary than in posthepatitic cirrhosis. Our results suggest that NCAM may have a function in the development of the intrahepatic bile ducts and that NCAM-positive immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases.

Predictive value of liver cell dysplasia for development of hepatocellular carcinoma in patients with non-cirrhotic and cirrhotic chronic viral hepatitis

AIMS

Hepatocellular carcinoma (HCC) frequently develops in patients with chronic viral hepatitis, especially in the cirrhotic stage. We retrospectively studied whether the presence of the putative preneoplastic lesions large liver cell dysplasia (LLCD) and/or small liver cell dysplasia (SLCD) in a needle liver biopsy of these patients are a risk factor for the development of HCC.

METHODS AND RESULTS

The presence of LLCD and SLCD in the needle liver biopsy taken at the initial work-up of 115 patients with chronic hepatitis B or C was assessed retrospectively. LLCD and SLCD were present in the initial biopsy of, respectively, 35 (30%) and 25 patients (22%). During a mean follow-up of 107 months, 16 patients (14%) developed HCC and this occurred significantly more frequently in patients with cirrhosis, age > or = 55 years, LLCD or SLCD. Cirrhosis and LLCD were independent risk factors for HCC development.

CONCLUSIONS

Our findings indicate that the presence of LLCD in a needle liver biopsy of patients with viral-induced chronic liver disease is an independent risk factor for the development of HCC. If these results are confirmed, the presence of LLCD can be used to identify a subgroup of patients at high risk for HCC requiring more intensive screening.

Deep intralobular extension of human hepatic 'progenitor cells' correlates with parenchymal inflammation in chronic viral hepatitis: can 'progenitor cells' migrate?

Ductular reaction and putative progenitor cells (or 'progenitor cells'), which are presumed to be the human counterpart of the oval cells in rat liver, have been discerned in various human liver diseases, including chronic viral hepatitis. Since in experimental models of chronic hepatitis the activation of oval cells is correlated with the inflammatory infiltrate, this study investigated whether there is a correlation in chronic viral hepatitis between the number of 'progenitor cells' extending into the lobule and the severity of parenchymal inflammation, on the one hand, and the extent of ductular reaction and the severity of interface hepatitis, on the other hand. Liver biopsies of 55 patients with chronic hepatitis B and/or C were used. The severity of parenchymal inflammation and of interface hepatitis was semiquantitatively graded on a haematoxylin and eosin-stained paraffin section, while the number of 'progenitor cells' and the extent of the ductular reaction were assessed on a serial section stained for cytokeratin (CK) 7. In addition, more extensive phenotyping of 'progenitor cells' was performed on sections from frozen material from five patients, using antibodies against CK7, CK8, CK18, CK19, chromogranin-A, and the rat oval cell marker OV-6. The number of more centrally located 'progenitor cells' correlated significantly with the severity of the parenchymal inflammation, while the extent of the ductular reaction correlated significantly with the severity of interface hepatitis. These findings suggest that in chronic viral hepatitis, inflammation plays a role in 'progenitor cell' activation and its topography. In cases with moderate and severe lobular inflammation, 'progenitor cells' were strikingly scattered throughout the parenchyma and surrounded by intermediate hepatocyte-like cells, suggesting their migration into the parenchyma and their differentiation towards the hepatocytic lineage.

Deep intralobular extension of human hepatic 'progenitor cells' correlates with parenchymal inflammation in chronic viral hepatitis: can 'progenitor cells' migrate?

Ductular reaction and putative progenitor cells (or 'progenitor cells'), which are presumed to be the human counterpart of the oval cells in rat liver, have been discerned in various human liver diseases, including chronic viral hepatitis. Since in experimental models of chronic hepatitis the activation of oval cells is correlated with the inflammatory infiltrate, this study investigated whether there is a correlation in chronic viral hepatitis between the number of 'progenitor cells' extending into the lobule and the severity of parenchymal inflammation, on the one hand, and the extent of ductular reaction and the severity of interface hepatitis, on the other hand. Liver biopsies of 55 patients with chronic hepatitis B and/or C were used. The severity of parenchymal inflammation and of interface hepatitis was semiquantitatively graded on a haematoxylin and eosin-stained paraffin section, while the number of 'progenitor cells' and the extent of the ductular reaction were assessed on a serial section stained for cytokeratin (CK) 7. In addition, more extensive phenotyping of 'progenitor cells' was performed on sections from frozen material from five patients, using antibodies against CK7, CK8, CK18, CK19, chromogranin-A, and the rat oval cell marker OV-6. The number of more centrally located 'progenitor cells' correlated significantly with the severity of the parenchymal inflammation, while the extent of the ductular reaction correlated significantly with the severity of interface hepatitis. These findings suggest that in chronic viral hepatitis, inflammation plays a role in 'progenitor cell' activation and its topography. In cases with moderate and severe lobular inflammation, 'progenitor cells' were strikingly scattered throughout the parenchyma and surrounded by intermediate hepatocyte-like cells, suggesting their migration into the parenchyma and their differentiation towards the hepatocytic lineage.

Deep intralobular extension of human hepatic 'progenitor cells' correlates with parenchymal inflammation in chronic viral hepatitis: can 'progenitor cells' migrate?

Ductular reaction and putative progenitor cells (or 'progenitor cells'), which are presumed to be the human counterpart of the oval cells in rat liver, have been discerned in various human liver diseases, including chronic viral hepatitis. Since in experimental models of chronic hepatitis the activation of oval cells is correlated with the inflammatory infiltrate, this study investigated whether there is a correlation in chronic viral hepatitis between the number of 'progenitor cells' extending into the lobule and the severity of parenchymal inflammation, on the one hand, and the extent of ductular reaction and the severity of interface hepatitis, on the other hand. Liver biopsies of 55 patients with chronic hepatitis B and/or C were used. The severity of parenchymal inflammation and of interface hepatitis was semiquantitatively graded on a haematoxylin and eosin-stained paraffin section, while the number of 'progenitor cells' and the extent of the ductular reaction were assessed on a serial section stained for cytokeratin (CK) 7. In addition, more extensive phenotyping of 'progenitor cells' was performed on sections from frozen material from five patients, using antibodies against CK7, CK8, CK18, CK19, chromogranin-A, and the rat oval cell marker OV-6. The number of more centrally located 'progenitor cells' correlated significantly with the severity of the parenchymal inflammation, while the extent of the ductular reaction correlated significantly with the severity of interface hepatitis. These findings suggest that in chronic viral hepatitis, inflammation plays a role in 'progenitor cell' activation and its topography. In cases with moderate and severe lobular inflammation, 'progenitor cells' were strikingly scattered throughout the parenchyma and surrounded by intermediate hepatocyte-like cells, suggesting their migration into the parenchyma and their differentiation towards the hepatocytic lineage.

Fas and Fas ligand: strong co-expression in human hepatocytes surrounding hepatocellular carcinoma; can cancer induce suicide in peritumoural cells?

Fas (Apo-1, CD95), a member of the nerve growth factor/tumour necrosis factor receptor superfamily, mediates apoptosis in response to agonistic antibodies or Fas ligand (Fas-L) binding. Fas has been shown to be present on hepatocyte membranes in normal liver and in chronic hepatitis C. At the present time, very limited data are available on the expression of Fas-L. This paper describes a study of 20 cases of active chronic hepatitis of different aetiologies, 20 hepatocellular carcinomas (HCCs) and the adjacent non-tumoural liver parenchyma, and five normal livers. The immunohistochemical expression of Fas and Fas-L was determined using specific monoclonal antibodies. In normal liver, Fas was faintly expressed on membranes of hepatocytes and bile duct cells, while Fas-L was negative. In active chronic hepatitis, Fas expression in hepatocytes was enhanced, resulting in a diffuse honeycomb pattern. Fas-L showed cytoplasmic positivity in hepatocytes in areas of interface hepatitis. Strong expression of Fas as well as Fas-L in the hepatocytes immediately adjacent to HCC was a constant finding. Within the HCCs, Fas-L expression was variable, but present only in a minority of cells. Fas varied from a diffuse honeycomb pattern to focal positivity in occasional cells. There was no correlation between Fas and Fas-L expression in the tumours. In conclusion, hepatocytes can co-express Fas and Fas-L in areas of interface hepatitis and adjacent to HCC, suggesting that they have the ability to induce apoptosis in an autocrine or paracrine way. Within the tumour, the Fas-Fas-L apoptosis pathway seems to be little involved.

The immunohistochemical phenotype of dysplastic foci in human liver: correlation with putative progenitor cells

BACKGROUND/AIMS

In previous studies we found strong evidence for the existence and activation in human liver of putative progenitor cells resembling oval cells in rat liver. In view of the known role of rat oval cells in regeneration and hepatocarcinogenesis, we investigated a possible correlation between human putative progenitor cells and different types of dysplastic foci.

METHODS

We determined the immunohistochemical phenotype of dysplastic foci found in 20 cirrhotic liver explants of various etiology, using specific antibodies against hepatocyte-type cytokeratin (CK) 8 and CK18, bile duct-type CK7 and CK19, chromogranin-A (chrom-A) and rat oval cell marker OV-6.

RESULTS

All 12 foci of large cell dysplasia had a phenotype similar to that of surrounding parenchyma. Oncocytic foci showed a strong cytoplasmic staining for CK7. Three out of six of these foci contained "progenitor cells", which are small cells immunoreactive for CK18, CK7, CK19, OV-6, chrom-A and stained more intensely for CK8 than surrounding hepatocytes. Four out of eight glycogen-storing foci contained CK7-positive intermediate hepatocyte-like cells and "progenitor cells". Sixteen out of 29 small cell dysplastic foci consisted of "progenitor cells" and intermediate hepatocyte-like cells which were immunoreactive for CK7, CK18, OV-6, chrom-A and showed a stronger cytoplasmic positivity for CK8 than surrounding hepatocytes.

CONCLUSIONS

Foci of large cell dysplasia show no correlation with putative progenitor cells. Half of the oncocytic and glycogen-storing foci contain "progenitor cells", while more than half of the foci of small cell dysplasia consist of small cells with the same immunohistochemical phenotype as putative progenitor cells and intermediate hepatocyte-like cells, suggesting that differentiating putative progenitor cells can give rise to foci of small cell dysplasia.

Fas and Fas ligand: strong co-expression in human hepatocytes surrounding hepatocellular carcinoma; can cancer induce suicide in peritumoural cells?

Fas (Apo-1, CD95), a member of the nerve growth factor/tumour necrosis factor receptor superfamily, mediates apoptosis in response to agonistic antibodies or Fas ligand (Fas-L) binding. Fas has been shown to be present on hepatocyte membranes in normal liver and in chronic hepatitis C. At the present time, very limited data are available on the expression of Fas-L. This paper describes a study of 20 cases of active chronic hepatitis of different aetiologies, 20 hepatocellular carcinomas (HCCs) and the adjacent non-tumoural liver parenchyma, and five normal livers. The immunohistochemical expression of Fas and Fas-L was determined using specific monoclonal antibodies. In normal liver, Fas was faintly expressed on membranes of hepatocytes and bile duct cells, while Fas-L was negative. In active chronic hepatitis, Fas expression in hepatocytes was enhanced, resulting in a diffuse honeycomb pattern. Fas-L showed cytoplasmic positivity in hepatocytes in areas of interface hepatitis. Strong expression of Fas as well as Fas-L in the hepatocytes immediately adjacent to HCC was a constant finding. Within the HCCs, Fas-L expression was variable, but present only in a minority of cells. Fas varied from a diffuse honeycomb pattern to focal positivity in occasional cells. There was no correlation between Fas and Fas-L expression in the tumours. In conclusion, hepatocytes can co-express Fas and Fas-L in areas of interface hepatitis and adjacent to HCC, suggesting that they have the ability to induce apoptosis in an autocrine or paracrine way. Within the tumour, the Fas-Fas-L apoptosis pathway seems to be little involved.

Malignant angiomyolipoma of the liver: a hitherto unreported variant

AIMS

After their original recognition in the kidney, angiomyolipomas (AMLs) have been reported in the liver for more than 20 years. In the kidney, five cases of malignant AML have been reported. We report the first case of malignant hepatic AML.

METHODS AND RESULTS

A 70-year-old female patient presented with abdominal discomfort. Clinical examination revealed a palpable liver. CT scan showed a polymorphous hypervascular lesion in the right liver lobe. A biopsy was taken and resulted initially in a differential diagnosis between a hepatocellular carcinoma, a metastatic tumour (possibly of renal origin) and angiomyolipoma (AML). After immunohistochemistry, a hepatic AML was suggested, given the immunoreactivity for HMB45/NKIC-3. The mass was resected 5 years later because of relapsing abscess formation. Gross examination of the resection specimen showed a focally encapsulated brown mass with focal necrosis. Microscopic examination showed a tumour growing in sheets, separated by sinusoidal-like vessels. Most of the tumour cells had a large, polygonal, clear cytoplasm, often with eosinophilic condensation around the nucleus. There was prominent vascular invasion. Immunohistochemistry (reactivity for HMB-45, NKIC-3, S100 and alpha smooth muscle actin, negativity for cytokeratin and vimentin) and electron microscopy confirmed the diagnosis of monomorphic epithelioid AML with prominent vascular invasion. Seven months after tumour resection, the patient died of recurrent disease.

CONCLUSIONS

This case highlights the importance of immunohistochemistry and electron microscopy in diagnosing this type of tumour. Possibly, in the past, malignant AML of the liver has been misdiagnosed as HCC.

Pericardial disease is often not recognised as a cause of chronic severe ascites

BACKGROUND/AIMS

Severe chronic ascites remains a difficult diagnostic and therapeutic problem. Even in the current era, constrictive pericarditis is an underestimated and sometimes unrecognised cause. Moreover, missing the diagnosis deprives patients of remedial therapy.

METHODS

Two cases of calcified constrictive pericarditis, complicated with cirrhosis and diagnosed in a late stage, are described. Due to insufficient clinical appreciation and lack of trust in echocardiography results, performed by cardiologists who were insufficiently familiar with the echocardiographic features of constrictive pericarditis, diagnosis was delayed in the two patients

RESULTS

The diagnosis of constrictive pericarditis as a cause of ascites is based upon the clinical signs of right heart failure in a patient with normal systolic left and right ventricular function and a high, serumascitic albumin-content difference. Complementary workup with complete Doppler echocardiography study, right and left heart catheterisation and MRI or cine CT of the heart is necessary to confirm the diagnosis.

CONCLUSION

Careful history taking and clinical examination remain the cornerstone of any diagnostic work-up, even in this era of technological refinement.

Synaptophysin: A novel marker for human and rat hepatic stellate cells

Synaptophysin is a protein involved in neurotransmitter exocytosis and is a neuroendocrine marker. We studied synaptophysin immunohistochemical expression in 35 human liver specimens (normal and different pathological conditions), in rat models of galactosamine hepatitis and carbon tetrachloride-induced cirrhosis, and in freshly isolated rat stellate cells. Synaptophysin reactivity was present in perisinusoidal stellate cells in both human and rat normal liver biopsies. The number of synaptophysin-reactive perisinusoidal cells increased in pathological conditions. Double staining for alpha-smooth muscle actin and synaptophysin, detected by confocal laser scanning microscopy, unequivocally demonstrated colocalization of both markers in lobular stellate cells. In addition, freshly isolated rat stellate cells expressed synaptophysin mRNA (detected by polymerase chain reaction) and protein. Finally, electron microscopy showed the presence of small electron translucent vesicles, comparable to the synaptophysin-reactive synaptic vesicles in neurons, in stellate cell projections. We conclude that synaptophysin is a novel marker for quiescent as well as activated hepatic stellate cells. Together with the stellate cell's expression of neural cell adhesion molecule, glial fibrillary acidic protein, and nestin, this finding raises questions about its embryonic origin and its differentiation. In addition, the presence of synaptic vesicles in stellate cell processes suggests a hitherto unknown mechanism of interaction with neighboring cells.

Ductular reaction and its diagnostic significance

Ductular reaction refers to an increased number of ductules (the finest ramifications of the biliary tree), accompanied by polymorphonuclear leukocytes and an increase in matrix, leading to periportal fibrosis and eventually biliary cirrhosis. It is a phenomenon that is seen in a variety of liver diseases, such as acute and chronic cholestasis and variable degrees of parenchymal necrosis. Ductular reaction has gained new interest because of its relationship with putative human liver progenitor cells. The existence of progenitor cells in a quiescent organ such as the liver, although still controversial, is important for the understanding of biological processes, such as embryogenesis, carcinogenesis, and regeneration. This article provides a diagnostic algorithm: Starting from the phenomenon of ductular reaction, portal tract and parenchymal changes that give diagnostic clues are systematically described.

Heparan sulphate proteoglycan expression in human primary liver tumours

Heparan sulphate proteoglycans (HSPGs) play important biological roles in cell-matrix adhesion processes and are essential regulators of growth factor actions (e.g., as co-receptor for hepatocyte growth factor). Since in liver carcinogenesis, interactions between cells, the matrix, and growth factors play a major role, the aim of this study was to investigate whether the distribution pattern of HSPGs is altered in human primary liver tumours. Twenty-two primary liver tumours and five normal liver biopsies were studied, using specific monoclonal antibodies against syndecans-1, -2, -3, and -4; glypican; perlecan; and heparan sulphate chains. Cholangiocarcinomas as well as hepatocellular carcinomas showed an altered immunoreactivity pattern of the different HSPGs in comparison with normal liver parenchyma, probably reflecting the growth regulatory roles of HSPGs. Intracellular positivity for integral membrane HSPGs syndecan-1 and especially syndecan-4 was a constant finding in most tumours, suggesting increased synthesis or internalization of these HSPGs. Syndecan-3 and perlecan expression in tumours was found in an expected distribution pattern. The strong reactivity for syndecan-3 and perlecan in tumoral stromal vessels might suggest a role for these HSPGs in tumoral angiogenesis. In addition, perlecan probably exerts its known growth factor reservoir function also in the stroma of primary liver tumours.

Heparan sulphate proteoglycan expression in human primary liver tumours

Heparan sulphate proteoglycans (HSPGs) play important biological roles in cell-matrix adhesion processes and are essential regulators of growth factor actions (e.g., as co-receptor for hepatocyte growth factor). Since in liver carcinogenesis, interactions between cells, the matrix, and growth factors play a major role, the aim of this study was to investigate whether the distribution pattern of HSPGs is altered in human primary liver tumours. Twenty-two primary liver tumours and five normal liver biopsies were studied, using specific monoclonal antibodies against syndecans-1, -2, -3, and -4; glypican; perlecan; and heparan sulphate chains. Cholangiocarcinomas as well as hepatocellular carcinomas showed an altered immunoreactivity pattern of the different HSPGs in comparison with normal liver parenchyma, probably reflecting the growth regulatory roles of HSPGs. Intracellular positivity for integral membrane HSPGs syndecan-1 and especially syndecan-4 was a constant finding in most tumours, suggesting increased synthesis or internalization of these HSPGs. Syndecan-3 and perlecan expression in tumours was found in an expected distribution pattern. The strong reactivity for syndecan-3 and perlecan in tumoral stromal vessels might suggest a role for these HSPGs in tumoral angiogenesis. In addition, perlecan probably exerts its known growth factor reservoir function also in the stroma of primary liver tumours.

Immunopathogenesis of conjunctival scarring in trachoma

PURPOSE

Trachoma, a chronic follicular conjunctivitis caused by infection with Chlamydia trachomatis, is the leading cause of preventable blindness. The blinding complications are associated with progressive conjunctival scarring that may result from immunologically mediated responses. We studied the processes involved in the regulation of inflammation and fibrosis in trachoma by investigating the expression of fibrogenic cytokines in the conjunctiva.

METHODS

We studied conjunctival biopsy specimens obtained from nine subjects with active trachoma and from four control subjects. We used immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies directed against interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha) and platelet-derived growth factor (PDGF). In addition, we characterised the composition of the inflammatory infiltrate by the use of a panel of monoclonal antibodies. Sirius red and Van Gieson stains were used to characterise the extent of fibrous tissue in the substantia propria.

RESULTS

Trachoma specimens showed greater numbers of inflammatory cells than control specimens. The expression of cytokines was absent in the normal conjunctiva. Cytoplasmic IL-1 alpha and IL-1 beta expression was noted in the conjunctival epithelium in all trachoma specimens. IL-1 alpha, IL-1 beta, TNF-alpha and PDGF were detected in macrophages infiltrating the substantia propria. B lymphocytes predominated over T lymphocytes in six trachoma biopsies with fibrosis confined to the deep substantia propria, whereas T lymphocytes predominated over B lymphocytes in three biopsies with more extensive fibrosis. In all trachoma biopsies helper/inducer T lymphocytes outnumbered suppressor/cytotoxic T lymphocytes.

CONCLUSIONS

The upregulated local production of IL-1 alpha, IL-beta, TNF-alpha and PDGF might contribute to conjunctival damage and scarring in trachoma.

Hepatic OV-6 expression in human liver disease and rat experiments: evidence for hepatic progenitor cells in man

BACKGROUND/AIMS/METHODS

Since in rat experiments, activation of progenitor cells is seen in conditions associated with hepatocyte injury or inhibited replication, we compared the activation and fate of human putative progenitor cells in regenerating liver versus chronic cholestatic disease, using immunohistochemistry, rat oval cell marker OV6 and a panel of bile ductular cell markers. We compared the results with different rat models: the choline-deficient acetylaminofluorene (CDAAF)- and alpha-naphthylisothiocyanate (ANIT)-model, using immunohistochemistry and electron microscopy.

RESULTS

In very early stages of human liver regeneration, putative progenitor cells in the vicinity of portal tracts were immunoreactive for OV6, CK7, CK19 and chrom-A. In later stages of regeneration and in chronic cholestasis, reactive bile ductules (immunoreactive for OV6, CK7, CK19, chrom-A, NCAM) and intermediate hepatocyte-like cells (immunoreactive for OV6, CK7, chrom-A), became apparent, suggesting bidirectional differentiation of the putative progenitor cells. In regenerating human liver, intermediate hepatocyte-like cells became more numerous with time and extended far into the lobule. In advanced cholestasis, intermediate hepatocyte-like cells were less numerous and formed periportal rosettes and small clusters. In the CDAAF rat model (associated with inhibited hepatocyte replication), but not in the ANIT model, gradual differentiation of oval cells into hepatocytes was seen after stopping the diet.

CONCLUSIONS

Our results in human liver suggest that reactive ductules and intermediate hepatocyte-like cells originate at least partly from activation and differentiation of "progenitor cells". In regeneration after submassive necrosis, in analogy with what is seen in rat models, differentiation towards hepatocytes is more pronounced than in chronic cholestasis.

Primary liver tumour of intermediate (hepatocyte-bile duct cell) phenotype: a progenitor cell tumour?

A 57-year-old female patient presented with painless obstructive jaundice and mild mesogastric pain; she was in good general condition on admission. Abdominal ultrasonography revealed diffuse tumoral invasion of the liver, suggesting diffuse metastases. A liver biopsy showed a tumour with a trabecular growth pattern, composed of uniform relatively small cells, very suggestive of an endocrine carcinoma. Additional immunohistochemical stains, however, did not show any endocrine differentiation, but showed positivity for both hepatocyte-type cytokeratins (cytokeratin 8 and 18) and bile duct-type cytokeratins (cytokeratin 7 and 19). In addition, parathyroid hormone-related peptide, shown to be a good marker for cholangiocarcinoma, was immunoreactive. Electron microscopy revealed tumour cells with an intermediate phenotype: the cells clearly showed hepatocyte features on one hand and bile duct cell features on the other hand. Nine days after admission, the patient died due to liver failure and hepatic encephalopathy. Autopsy excluded another primary tumour site. Overall, this tumour was a primary liver tumour with an intermediate phenotype and with a very rapid clinical course. The intermediate (between hepatocyte and bile duct cell) phenotype suggests an immature progenitor cell origin, which is concordant with a rapid clinical course. This type of tumour has not been described previously and provides additional evidence for the existence of progenitor cells in human liver.

Nimesulide-induced acute hepatitis: evidence from six cases

BACKGROUND/AIMS

A number of nonsteroidal anti-inflammatory drugs have been reported to provoke hepatic injury. Nimesulide is a new agent of the sulfonanilide class, and is a more selective inhibitor of cyclooxygenase type 2 than of type 1. Well-documented cases of acute hepatitis have not yet been reported with this drug. We report on six patients who developed acute liver damage after initiation of nimesulide.

METHODS

Between April 1996 and January 1997, six patients with apparent nimesulide-induced liver injury were admitted. Clinical, laboratory, serologic, radiological, and histologic data of all six cases were extensively analyzed. The causal relationship between nimesulide and liver injury was assessed, using a scoring system elaborated by the French and International consensus meeting group.

RESULTS

Four women developed a centrilobular (three) or panlobular (one) bridging necrosis, whereas two men showed a bland intrahepatic cholestasis. Jaundice was the presenting symptom in five of the six cases. One patient with hepatocellular necrosis and one with cholestasis had hallmarks of hypersensitivity with an increased blood and tissue eosinophilia. The causal relationship could be designated as "highly probable" in one, "probable" in four, and "possible" in one patient. One patient died from a pancreatic tumor 5 months after the diagnosis of toxic liver injury. In all other patients, liver tests returned to completely normal values within a late follow-up period of 6 to 17 months.

CONCLUSIONS

Nimesulide-induced liver injury can present with hepatocellular necrosis or with pure cholestasis. From clinical and histologic data, it appears that both immunologic and metabolic idiosyncratic reactions can be invoked as the pathogenic mechanisms of nimesulide-induced liver disease.

NO synthase in the liver: prospects of in vivo gene transfer

Portal hypertension is a major complication of cirrhosis, portal vein thrombosis, presinusoidal liver diseases such as schistosomiasis and postsinusoidal disorders such as veno-occlusive disease or Budd-Chiari syndrome. The elevated pressure results from enhanced resistance in the portal venous system and from augmented influx of blood due to splanchnic vasodilatation and hypervolemia [1]. The enhanced intrahepatic resistance in cirrhotic livers is partly due to fibrosis [2] and partly to active vasoconstriction, since Bathal and Grossman [3] could demonstrate in the isolated perfused cirrhotic rat liver that the increased portal vascular resistance could be decreased by medication.

Heparan sulphate proteoglycan expression in human primary liver tumours

Heparan sulphate proteoglycans (HSPGs) play important biological roles in cell-matrix adhesion processes and are essential regulators of growth factor actions (e.g., as co-receptor for hepatocyte growth factor). Since in liver carcinogenesis, interactions between cells, the matrix, and growth factors play a major role, the aim of this study was to investigate whether the distribution pattern of HSPGs is altered in human primary liver tumours. Twenty-two primary liver tumours and five normal liver biopsies were studied, using specific monoclonal antibodies against syndecans-1, -2, -3, and -4; glypican; perlecan; and heparan sulphate chains. Cholangiocarcinomas as well as hepatocellular carcinomas showed an altered immunoreactivity pattern of the different HSPGs in comparison with normal liver parenchyma, probably reflecting the growth regulatory roles of HSPGs. Intracellular positivity for integral membrane HSPGs syndecan-1 and especially syndecan-4 was a constant finding in most tumours, suggesting increased synthesis or internalization of these HSPGs. Syndecan-3 and perlecan expression in tumours was found in an expected distribution pattern. The strong reactivity for syndecan-3 and perlecan in tumoral stromal vessels might suggest a role for these HSPGs in tumoral angiogenesis. In addition, perlecan probably exerts its known growth factor reservoir function also in the stroma of primary liver tumours.

Adhesion molecules in vernal keratoconjunctivitis

AIMS/BACKGROUND

Adhesion molecules play a key role in the selective recruitment of different leucocyte population to inflammatory sites. The purpose of the present study was to investigate the presence and distribution of adhesion molecules in the conjunctiva of patients with vernal keratoconjunctivitis (VKC).

METHODS

The presence and distribution of adhesion molecules were studied in 14 conjunctival biopsy specimens from seven patients with active VKC and in four normal conjunctival biopsy specimens. We used a panel of specific monoclonal antibodies (mAbs) directed against intercellular adhesion molecule-1 (ICAM-1), intercellular adhesion molecule-3 (ICAM-3), lymphocyte function associated antigen-1 (LFA-1), very late activation antigen-4 (VLA-4), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leucocyte adhesion molecule-1 (ELAM-1) In addition, a panel of mAbs were used to characterise the composition of the inflammatory infiltrate.

RESULTS

In the normal conjunctiva, ICAM-1 was expressed on the vascular endothelium only, LFA-1 and ICAM-3 on epithelial and stromal mononuclear cells, and VLA-4 on stromal mononuclear cells. The expression of VCAM-1 and ELAM-1 was absent. The number of cells expressing adhesion molecules was found to be markedly increased in all VKC specimens. This was concurrent with a heavy inflammatory infiltrate. Strong ICAM-1 expression was induced on the basal epithelial cells, and vascular endothelial cells. Furthermore, ICAM-I was expressed on stromal mononuclear cells. LFA-1 and ICAM-3 were expressed on the majority of epithelial and stromal infiltrating mononuclear cells. VLA-4 expression was noted on stromal mononuclear cells. Compared with controls, VKC specimens showed significantly more ICAM-3+, LFA-3+, LFA-1+, and VLA-4+ cells. VCAM-1 and ELAM-1 were induced on the vascular endothelial cells.

CONCLUSIONS

Increased expression of adhesion molecules may play an important role in the pathogenesis of VKC.