Endogenous interleukin-22 protects against inflammatory bowel disease but not autoimmune cholangitis in dominant negative form of transforming growth factor beta receptor type II mice.

During chronic inflammation, interleukin (IL)-22 expression is up-regulated in both CD4 and CD8 T cells, exerting a protective role in infections. However, in autoimmunity, IL-22 appears to have either a protective or a pathogenic role in a variety of murine models of autoimmunity and, by extrapolation, in humans. It is not clear whether IL-22 itself mediates inflammation or is a by-product of inflammation. We have taken advantage of the dominant negative form of transforming growth factor beta receptor type II (dnTGF-ßRII) mice that develop both inflammatory bowel disease and autoimmune cholangitis and studied the role and the biological function of IL-22 by generating IL-22(-/-) dnTGF-ßRII mice. Our data suggest that the influence of IL-22 on autoimmunity is determined in part by the local microenvironment. In particular, IL-22 deficiency exacerbates tissue injury in inflammatory bowel disease, but has no influence on either the hepatocytes or cholangiocytes in the same model. These data take on particular significance in the previously defined effects of IL-17A, IL-12p40 and IL-23p19 deficiency and emphasize that, in colitis, there is a dominant role of IL-23/T helper type 17 (Th17) signalling. Furthermore, the levels of IL-22 are IL-23-dependent. The use of cytokine therapy in patients with autoimmune disease has significant potential, but must take into account the overlapping and often promiscuous effects that can theoretically exacerbate inflammation.

Immunological potential of cytotoxic T lymphocyte antigen 4 immunoglobulin in murine autoimmune cholangitis.

Cytotoxic T lymphocyte antigen 4 (CTLA-4) immunoglobulin (Ig) is an important regulator of T cell activation and a fusion protein directed at CD80 and CD86; it blocks co-stimulatory signalling and T cell activation. We have taken advantage of a murine model of human primary biliary cirrhosis (PBC), mice expressing a transforming growth factor (TGF)-ß receptor II dominant negative (dnTGF-ßRII) transgene to address the potential therapeutic efficacy of CTLA-4 Ig. To mimic patients with PBC at different stages or duration of disease, we treated mice with either CTLA-4 Ig or control IgG three times weekly from 3 to 12 or 24 weeks of age, or from 12 to 24 weeks of age. CTLA-4 Ig treatment from 3 weeks of age significantly reduced liver inflammation to 12 weeks of age. Treatment initiated at 12 weeks of age also ameliorated the autoimmune cholangitis at 24 weeks of age. However, in mice treated at 3 weeks of age, suppression of liver inflammation was not sustained and colitis was aggravated when treatment was extended to 24 weeks of age. Our data indicate that, in dnTGF-ßRII mice, CTLA-4 Ig treatment has short-term beneficial effects on autoimmune cholangitis, but the effect varies according to duration of treatment and the time in which therapy was initiated. Further dissection of the events that lead to the reduction in therapeutic effectiveness of CTLA-4 Ig will be critical to determining whether such efforts can be applied to human PBC.

Reversible phospho-Smad3 signalling between tumour suppression and fibrocarcinogenesis in chronic hepatitis B infection.

Transforming growth factor (TGF)-ß, type I receptor (TßRI) and c-Jun N-terminal kinases (JNK) phosphorylate Smad3 differentially to create 2 isoforms phosphorylated (p) at the COOH-terminus (C) or at the linker region (L) and regulate hepatocytic fibrocarcinogenesis. This study aimed to compare the differences between how hepatitis B virus (HBV) infection affected hepatocytic Smad3 phosphorylated isoforms before and after anti-viral therapy. To clarify the relationship between Smad3 phosphorylation and liver disease progression, we studied 10 random patients in each stage of HBV-related fibrotic liver disease (F1-4) and also 10 patients with HBV-associated HCC. To examine changes in phosphorylated Smad3 signalling before and after anti-HBV therapies, we chose 27 patients with chronic hepatitis B who underwent baseline and follow-up biopsies at 52 weeks from the start of nucleoside analogue treatments (Lamivudine 100 mg daily or Telbivudine 600 mg daily). Fibrosis stage, inflammatory activity and phosphorylated Smad3 positivity in the paired biopsy samples were compared. Hepatocytic pSmad3C signalling shifted to fibrocarcinogenic pSmad3L signalling as the livers progressed from chronic hepatitis B infection to HCC. After nucleoside analogue treatment, serum alanine aminotransferase (ALT) and HBV-DNA levels in 27 patients with HBV-related chronic liver diseases were decreased dramatically. Decrease in HBV-DNA restored pSmad3C signalling in hepatocytes, while eliminating prior fibrocarcinogenic pSmad3L signalling. Oral nucleoside analogue therapies can suppress fibrosis and reduce HCC incidence by successfully reversing phosphorylated Smad3 signalling; even liver disease progressed to cirrhosis in chronic hepatitis B patients.

Successful immunotherapy of autoimmune cholangitis by adoptive transfer of forkhead box protein 3(+) regulatory T cells.

Treatment of primary biliary cirrhosis (PBC) has lagged behind that of other autoimmune diseases. In this study we have addressed the potential utility of immunotherapy using regulatory T cells (Treg ) to treat murine autoimmune cholangitis. In particular, we have taken advantage of our ability to produce portal inflammation and bile duct cell loss by transfer of CD8(+) T cells from the dominant negative form of transforming growth factor beta receptor type II (dnTGF-ßRII) mice to recombination-activating gene (Rag)1(-/-) recipients. We then used this robust established adoptive transfer system and co-transferred CD8(+) T cells from dnTGF-ßRII mice with either C57BL/6 or dnTGF-ßRII forkhead box protein 3 (FoxP3(+) ) T cells. Recipient mice were monitored for histology, including portal inflammation and intralobular biliary cell damage, and also included a study of the phenotypical changes in recipient lymphoid populations and local and systemic cytokine production. Importantly, we report herein that adoptive transfer of Treg from C57BL/6 but not dnTGF-ßRII mice significantly reduced the pathology of autoimmune cholangitis, including decreased portal inflammation and bile duct damage as well as down-regulation of the secondary inflammatory response. Further, to define the mechanism of action that explains the differential ability of C57BL/6 Treg versus dnTGF-ßRII Treg on the ability to down-regulate autoimmune cholangitis, we noted significant differential expression of glycoprotein A repetitions predominant (GARP), CD73, CD101 and CD103 and a functionally significant increase in interleukin (IL)-10 in Treg from C57BL/6 compared to dnTGF-ßRII mice. Our data reflect the therapeutic potential of wild-type CD4(+) FoxP3(+) Treg in reducing the excessive T cell responses of autoimmune cholangitis, which has significance for the potential immunotherapy of PBC.

Escherichia coli infection induces autoimmune cholangitis and anti-mitochondrial antibodies in non-obese diabetic (NOD).B6 (Idd10/Idd18) mice.

Several epidemiological studies have demonstrated that patients with primary biliary cirrhosis (PBC) have a higher incidence of urinary tract infections (UTI) and there is significant homology of the immunodominant mitochondrial autoantigen, the E2 component of the pyruvate dehydrogenase complex (PDC-E2), between mammals and bacteria. Previous work has demonstrated that non-obese diabetic (NOD).B6 Idd10/Idd18 infected with Novosphingobium aromaticivorans developed liver lesions similar to human PBC. It was postulated that the biliary disease was dependent upon the presence of the unique N. aro glycosphingolipids in activating natural killer T (NK T) cells. To address this issue, we infected NOD.B6 Idd10/Idd18 mice with either Escherichia coli, N. aro or use of a phosphate-buffered saline (PBS) vehicle control and serially followed animals for the appearance of liver pathology and anti-mitochondrial autoantibodies (AMA). Of striking importance, the biliary disease of E. coli-infected mice was more severe than N. Aro-infected mice and the titre of AMA was higher in E. coli-infected mice. Furthermore, the immunopathology did not correlate with the ability of bacterial extracts to produce antigen-dependent activation of NK T cells. Our data suggest that the unique glycosphingolipids of N. aro are not required for the development of autoimmune cholangitis. Importantly, the data highlight the clinical significance of E. coli infection in a genetically susceptible host, and we suggest that the appearance of autoimmune cholangitis is dependent upon molecular mimicry. These data highlight that breach of tolerance to PDC-E2 is probably the first event in the natural history of PBC in genetically susceptible hosts.

Adipose tissue hypoxia induces inflammatory M1 polarity of macrophages in an HIF-1α-dependent and HIF-1α-independent manner in obese mice.

AIMS/HYPOTHESIS: As obesity progresses, adipose tissue exhibits a hypoxic and inflammatory phenotype characterised by the infiltration of adipose tissue macrophages (ATMs). In this study, we examined how adipose tissue hypoxia is involved in the induction of the inflammatory M1 and anti-inflammatory M2 polarities of ATMs. METHODS: The hypoxic characteristics of ATMs were evaluated using flow cytometry after the injection of pimonidazole, a hypoxia probe, in normal-chow-fed or high-fat-fed mice. The expression of hypoxia-related and inflammation-related genes was then examined in M1/M2 ATMs and cultured macrophages. RESULTS: Pimonidazole uptake was greater in M1 ATMs than in M2 ATMs. This uptake was paralleled by the levels of inflammatory cytokines, such as TNF-α, IL-6 and IL-1ß. The expression level of hypoxia-related genes, as well as inflammation-related genes, was also higher in M1 ATMs than in M2 ATMs. The expression of Il6, Il1ß and Nos2 in cultured macrophages was increased by exposure to hypoxia in vitro but was markedly decreased by the gene deletion of Hif1a. In contrast, the expression of Tnf, another inflammatory cytokine gene, was neither increased by exposure to hypoxia nor affected by Hif1a deficiency. These results suggest that hypoxia induces the inflammatory phenotypes of macrophages via Hif1a-dependent and -independent mechanisms. On the other hand, the expression of inflammatory genes in cultured M2 macrophages treated with IL-4 responded poorly to hypoxia. CONCLUSIONS/INTERPRETATION: Adipose tissue hypoxia induces an inflammatory phenotype via Hif1a-dependent and Hif1a-independent mechanisms in M1 ATMs but not in M2 ATMs.

Anti-CD40 ligand monoclonal antibody delays the progression of murine autoimmune cholangitis.

While there have been significant advances in our understanding of the autoimmune responses and the molecular nature of the target autoantigens in primary biliary cirrhosis (PBC), unfortunately these data have yet to be translated into new therapeutic agents. We have taken advantage of a unique murine model of autoimmune cholangitis in which mice expressing a dominant negative form of transforming growth factor ß receptor II (dnTGFßRII), under the control of the CD4 promoter, develop an intense autoimmune cholangitis associated with serological features similar to human PBC. CD40-CD40 ligand (CD40L) is a major receptor-ligand pair that provides key signals between cells of the adaptive immune system, prompting us to determine the therapeutic potential of treating autoimmune cholangitis with anti-CD40L antibody (anti-CD40L; MR-1). Four-week-old dnTGFßRII mice were injected intraperitoneally with either anti-CD40L or control immunoglobulin (Ig)G at days 0, 2, 4 and 7 and then weekly until 12 or 24 weeks of age and monitored for the progress of serological and histological features of PBC, including rigorous definition of liver cellular infiltrates and cytokine production. Administration of anti-CD40L reduced liver inflammation significantly to 12 weeks of age. In addition, anti-CD40L initially lowered the levels of anti-mitochondrial autoantibodies (AMA), but these reductions were not sustained. These data indicate that anti-CD40L delays autoimmune cholangitis, but the effect wanes over time. Further dissection of the mechanisms involved, and defining the events that lead to the reduction in therapeutic effectiveness will be critical to determining whether such efforts can be applied to PBC.

The role of natural killer (NK) and NK T cells in the loss of tolerance in murine primary biliary cirrhosis.

One of the major obstacles in dissecting the mechanism of pathology in human primary biliary cirrhosis (PBC) has been the absence of animal models. Our laboratory has focused on a model in which mice, following immunization with a xenobiotic chemical mimic of the immunodominant autoepitope of the E2 component of pyruvate dehydrogenase complex (PDC-E2), develop autoimmune cholangitis. In particular, following immunization with 2-octynoic acid (a synthetic chemical mimic of lipoic acid-lysine located within the inner domain of PDC-E2) coupled to bovine serum albumin (BSA), several strains of mice develop typical anti-mitochondrial autoantibodies and portal inflammation. The role of innate immune effector cells, such as natural killer (NK) cells and that NK T cells, was studied in this model based on the hypothesis that early events during immunization play an important role in the breakdown of tolerance. We report herein that, following in-vivo depletion of NK and NK T cells, there is a marked suppression of anti-mitochondrial autoantibodies and cytokine production from autoreactive T cells. However, there was no change in the clinical pathology of portal inflammation compared to controls. These data support the hypothesis that there are probably multiple steps in the natural history of PBC, including a role of NK and NK T cells in initiating the breakdown of tolerance. However, the data suggest that adaptive autoimmune effector mechanisms are required for the progression of clinical disease.

Modulation of CD4⁺ T cell responses following splenectomy in hepatitis C virus-related liver cirrhosis.

Dysfunction of T cells is a common feature in chronic persistent viral infections, including hepatitis C virus (HCV), and although hepatic and peripheral T cells have been studied extensively in chronic HCV hepatitis, the role of splenic T cell responses in such patients is poorly defined. This is an important issue, as thrombocytopenia is a complication of HCV-related liver cirrhosis (LC), due to splenic platelet sequestration and bone marrow suppression; splenectomy has been proposed to treat such patients. Herein, we studied peripheral blood mononuclear cells (PBMC) and splenic lymphoid subpopulations from a total of 22 patients, including 15 with HCV-related LC with marked thrombocytopenia treated with splenectomy, and seven controls. CD4(+) T cells from peripheral blood and spleen were isolated and phenotype and function evaluated. Splenic CD4(+) T cells in patients with LC expressed molecules associated with inhibitory signalling, including increased frequency of negative markers such as cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death 1 (PD-1) and decreased production of cytokines. Patients with LC manifest higher levels of splenic CD4(+) regulatory T cells and PD-L1- and PD-L2-expressing cells than controls. Blocking of PD-1/PD-1 ligand interaction reconstituted proliferative and cytokine responses of splenic mononuclear cells (SMC) from patients with LC. Splenectomy was followed by an increase in the ratio of interferon (IFN)-γ to interleukin (IL)-10 and a reduction of PD-1-expressing CD4(+) T cells in peripheral blood. Our data suggest that peripheral tolerance is promoted by the spleen in LC via the up-regulated expression of PD-1 ligands.

The multi-hit hypothesis of primary biliary cirrhosis: polyinosinic-polycytidylic acid (poly I:C) and murine autoimmune cholangitis.

A void in understanding primary biliary cirrhosis (PBC) is the absence of appropriate animal models. Our laboratory has studied a murine model of autoimmune cholangitis induced following immunization with 2-octynoic acid (2OA), an antigen identified following extensive quantitative structural activity relationship (QSAR) analysis, using human autoantibodies and three-dimensional analysis of the mitochondrial autoantigen, the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2). Mice immunized with 2OA coupled to bovine serum albumin (BSA) develop anti-mitochondrial antibodies (AMAs) of the identical specificity as humans with PBC, and in addition develop inflammatory portal cell infiltrates in liver. However, the natural history of disease is less severe than in humans and does not include fibrosis. Data from human and autoimmune murine models suggest that environmental and/or infectious agents can exacerbate autoimmune reactions, and a model of PBC has been described in which polyinosinic-polycytidylic acid (poly I:C), a viral RNA mimetic and Toll-like receptor 3 (TLR-3) agonist induces low-titre AMAs and in mild portal infiltrates. We took advantage of our established model to determine whether immunization with 2OA-BSA coupled with poly I:C alters the disease process. Indeed, the addition of poly I:C produces a profound exacerbation of autoimmune cholangitis, including a significant increase in CD8(+) infiltrating T cells, as well as a marked increase of proinflammatory cytokines. In addition, mice have evidence of fibrosis. These findings lend support to the concept that besides breakdown of self-tolerance, there is a requirement of a second 'hit' during the breakdown process that leads to disease which more faithfully mimics human PBC.

Beta-glucosylceramide ameliorates liver inflammation in murine autoimmune cholangitis.

We have demonstrated spontaneous development of autoimmune cholangitis, similar to human primary biliary cirrhosis, in mice expressing a dominant negative form of the transforming growth factor-beta receptor (dnTGF-betaRII) restricted to T cells. The autoimmune cholangitis appears to be mediated by autoreactive CD8(+) T lymphocytes that home to the portal tracts and biliary system. Because the liver pathology is primarily secondary to CD8(+) T cells, we have determined herein whether administration of beta-glucosylceramide (GC), a naturally occurring plant glycosphingolipid, alters the natural history of disease in this model. We chose GC because previous work has demonstrated its ability to alter CD8(+) T cell responses and to down-regulate tissue inflammation. Accordingly, dnTGF-betaRII mice were treated with either GC or control for a period of 18 weeks beginning at 6 weeks of age. Importantly, in mice that received GC, there was a significant decrease in the frequency and absolute number of autoreactive liver-infiltrating CD8(+) T cells, accompanied by a significant decrease in activated CD44(high) CD8(+) T cell populations. Further, there was a significant reduction in portal inflammation in GC-treated mice. Interestingly, there were no changes in anti-mitochondrial antibodies, CD4(+) T cells, CD19(+) B cells or natural killer (NK) T cell populations, indicating further that the beneficial effects of GC on liver inflammation were targeted specifically to liver-infiltrating CD8(+) T cells. These data suggest that further work on GC in models of CD8(+) T-mediated inflammation are needed and point to a new therapeutic venue for potentially treating and/or modulating autoimmune disease.

Induction of autoimmune cholangitis in non-obese diabetic (NOD).1101 mice following a chemical xenobiotic immunization.

Our laboratory has suggested that loss of tolerance to pyruvate dehydrogenase (PDC-E2) leads to an anti-mitochondrial antibody response and autoimmune cholangitis, similar to human primary biliary cirrhosis (PBC). We have suggested that this loss of tolerance can be induced either via chemical xenobiotic immunization or exposure to select bacteria. Our work has also highlighted the importance of genetic susceptibility. Using the non-obese diabetic (NOD) congenic strain 1101 (hereafter referred to as NOD.1101 mice), which has chromosome 3 regions from B6 introgressed onto a NOD background, we exposed animals to 2-octynoic acid (2OA) coupled to bovine serum albumin (BSA). 2OA has been demonstrated previously by a quantitative structural activity relationship to react as well as or better than lipoic acid to anti-mitochondrial antibodies. We demonstrate herein that NOD.1101 mice immunized with 2OA-BSA, but not with BSA alone, develop high titre anti-mitochondrial antibodies and histological features, including portal infiltrates enriched in CD8(+) cells and liver granulomas, similar to human PBC. We believe this model will allow the rigorous dissection of early immunogenetic cause of biliary damage.

An unusual case of epithelial-myoepithelial carcinoma of the liver.

The authors present an unusual case of an epithelial-myoepithelial carcinoma of the liver in a 67-year-old man who was admitted for resection of a gastric adenocarcinoma. At operation, a 3 x 3 cm mass in the right liver lobe was also removed. This mass consisted of duct-like structures with dual differentiation. The inner layer was composed of an epithelial lining, and the outer layer consisted of clear cells, all unrelated to the moderately well-differentiated gastric adenocarcinoma. The clear cells were positive for S-100 and alpha-smooth muscle actin, suggesting myoepithelial origin. The mass was considered to be low-grade epithelial-myoepithelial carcinoma. However, the patient had a history of an oral nodule present since childhood, resected 10 years previously. These slides were reviewed and revealed a mixture of clear cells and basal cells with squamous differentiation. In addition, there were duct-like structures with the two-layer pattern found in the liver tumor. This tumor had numerous mitotic figures and showed perineural invasion, suggesting a high grade of malignancy. These findings led to an interpretation of the oral tumor as also being epithelial-myoepithelial carcinoma, which had remained as "benign" for more than 50 years and subsequently underwent malignant transformation. During this long period, liver metastases may have occurred and remained low-grade. Alternatively, the liver and oral tumors may have arisen separately in the foregut during embryologic development, remaining low-grade until malignant transformation occurred.

Primary biliary cirrhosis an epithelitis: evidence of abnormal salivary gland immunohistochemistry.

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology. Nearly 93% of patients with PBC exhibit evidence of focal sialoadenitis. In an earlier study, we reported evidence of aberrant expression of PDC-E2, or a mimeotope, in the salivary glands of patients with PBC that had Sjogren's syndrome. At the time of the previous study, data was not yet available regarding patients with PBC without sicca complaints. Therefore, to investigate the extent of salivary gland involvement in PBC, we collected lip biopsy sections from 9 PBC patients diagnosed as PBC by liver biopsy, without clinical or histologic features of Sjogren's syndrome and 9 PBC patients with established Sjogren's syndrome. Using immunohistochemical staining with both a murine monoclonal antibody. C355.1, and a human combinatorial antibody, SP4, we examined the ducts of these salivary glands for the presence of the characteristic aberrant staining pattern found in patients with PBC. We report that 6/9 PBC patients fulfilling established Sjogren's syndrome criteria and 6/9 PBC patients lacking features of Sjogren's syndrome showed intense staining of the ductal epithelial cells of the salivary gland. These data suggest that the PBC-specific antigen recognized by C355.1 and SP4 in bile duct epithelial cells is expressed aberrantly in the salivary gland in 66% of patients with PBC, independent of Sjogren's syndrome. This finding suggests a common disease process in these two tissues. Further, expression of this molecule may be an early marker of salivary gland involvement in patients with PBC.

Hepatic inflammatory pseudotumor associated with chronic cholangitis: report of three cases.

We present three cases of hepatic inflammatory pseudotumor associated with chronic cholangitis. In these three cases the inflammatory pseudotumor was solitary, was present in the hepatic hilar region, and had been misdiagnosed as cholangiocarcinoma by imaging modalities and/or gross pathologic examination. Hilar bile ducts were embedded within the tumor. Histologically, these "tumors" consisted of an 2ad-mixed proliferation of lymphocytes, plasma cells, and fibroblasts with variable hyaline fibrosis. The phenotypes of lymphocytes and plasma cells within the tumor were immunohistochemically heterogeneous. Bile ducts and peribiliary glands embedded within these tumors showed nonspecific fibrosis and inflammation, and inflammatory changes of the bile ducts were imperceptibly merged with those of the inflammatory tumor, raising the possibility that these tumors may have arisen in relation to cholangitis. The bile ducts adjacent to the tumor also showed similar but milder nonspecific inflammatory changes. The pathogenesis of cholangitis was unknown in two cases and was speculated to be due to fungal infection in the remaining case. These cases may indicate that biliary tract disease(s) should be explored as the etiology of hepatic inflammatory pseudotumor.

Biliary epithelial expression of pyruvate dehydrogenase complex in primary biliary cirrhosis: an immunohistochemical and immunoelectron microscopic study.

It has been reported recently that there is a unique distribution of the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2) on biliary epithelial cells in patients with primary biliary cirrhosis (PBC) but not primary sclerosing cholangitis. This distribution has been demonstrated using a mouse monoclonal antibody, coined C355.1. The epitope recognized by C355.1 is near the lipoic acid binding site of PDC-E2. C355.1 inhibits PDC-E2 activity in vitro and, unlike a panel of other monoclonal antibodies against different regions of PDC-E2, appears to bind not only to mitochondria but also to a unique antigen expressed predominantly on the luminal side of biliary epithelial cells in PBC. We have extended these observations by studying the subcellular reactivity of C355.1 using postembedding immunoelectron microscopy on the intrahepatic small bile ducts of PBC livers, extrahepatic biliary obstruction (EBO) livers, and normal livers. We report that the reactivity of C355.1 can be classified into two categories. The first category is characterized by small foci of reaction products that were randomly dispersed in cytoplasm, particularly in supranuclear areas; the ultrastructural characterization of these foci was impossible to define but was similar in PBC and EBO. However, of particular interest was the second category of reactivity, which was characterized by deposition of reaction products around the biliary lumen, including microvilli and adjacent subluminal ectoplasm and secretory substances in the biliary lumen. This staining pattern was frequent in PBC livers, only occasionally evident in EBO livers, and not found in normal livers. These data further define and highlight the unique subcellular distribution of PDC-E2 around the biliary lumen in PBC livers and suggest that this abnormality is related to the pathogenesis of bile duct lesions.

Distribution of intrahepatic mast cells in various hepatobiliary disorders. An immunohistochemical study.

There is evidence that mast cells are involved in a number of pathophysiological processes. The significance of mast cells in hepatic fibrosis was examined in 28 patients with histologically normal livers, 34 with acute liver diseases, 51 with chronic liver diseases, and 59 with cholestatic biliary diseases, using immunostaining of the mast cell-specific proteinase, tryptase. Mast cells that were positive for tryptase and for chymase were significantly increased in frequency in fibrotic portal tracts and fibrous septa, particularly in cholestatic/biliary diseases. Mast cells were also increased in frequency around the fibrotic septal and intrahepatic large bile ducts and peribiliary glands of biliary diseases. However, they were less common or even rare in the sclerotic bile ducts and in scarred portal or septal fibrosis. More than half of these more numerous mast cells were positive for histamine, and some were also positive for basic fibroblast growth factor. These two substances were detectable by immunoelectron microscopic in the cytoplasmic granules of mast cells. In contrast, mast cell numbers were not significantly increased in acute viral or drug-induced hepatitis, or in zones 2 and 3 of the hepatic acinus with respect to pericellular and perivenular fibrosis in chronic liver diseases. These findings suggest that mast cells increase in number in cholestatic/biliary diseases, and to a lesser degree in chronic liver diseases, and are involved in the active fibrous enlargement of portal tract and fibrous septa formation and also in the fibrosis of the intrahepatic bile ducts as they display fibrosis-promoting factors such as tryptase, fibroblast growth factor and histamine.

Pathology and pathogenesis of idiopathic portal hypertension with an emphasis on the liver.

Idiopathic portal hypertension (IPH) is characterized by a long-standing presinusoidal portal hypertension of unknown etiology in adults. Some unidentified agent(s) affect(s) the intrahepatic small portal veins or portal tracts. Immunological disturbance, thromboembolism, infectious etiology and/or increased fibrogenesis in portal tracts are suspected as being candidates for the primary agent(s). During the long clinical course of IPH, several pathological changes may occur, including subcapsular parenchymal atrophy, atrophy of the liver, portal and parenchymal fibrosis, and portal venous phlebosclerosis and thrombosis. The last-named of these lesions is mostly found in patients with a history of splenectomy. Subcapsular parenchymal and hepatic atrophy may result from a hepatocellular dropout via apoptosis or necrosis because of intrahepatic hemodynamic disturbances, particularly chronic portal venous blood insufficiency. Pericellular fibrosis and thin fibrous septa are also frequently found and associated with activated perisinusoidal cells positive for smooth muscle actin. At the same time, vague nodular hyperplasia of hepatocytes not surrounded by fibrous septa is not infrequently seen. It may resemble nodular regenerative hyperplasia, partial nodular transformation, or focal nodular hyperplasia. However, liver cirrhosis does not occur even at the terminal stage. Taking these findings into consideration, a new staging of IPH with a combination of hepatic parenchymal atrophy and portal venous thrombosis was proposed: non-atrophic liver without subcapsular parenchymal atrophy (stage I), non-atrophic liver with subcapsular parenchymal atrophy (stage II), atrophic liver with subcapsular parenchymal atrophy (stage III), and portal venous occlusive thrombosis (stage IV). IPH livers are likely to progress from stage I to stage III. Stage IV, which occurs relatively late, has a poor prognosis. This staging is applicable to clinical and autopsy cases without any histological data.

A case report of gastric carcinosarcoma with rhabdomyosarcomatous and neuroendocrinal differentiation.

We report herein an unusual gastric carcinosarcoma with rhabdomyosarcomatous and neuroendocrinal differentiation in a 63-year-old Japanese male. The tumor was a pedunculated large polypoid tumor (7 x 6.5 x 3.5 cm) located in the pylorus. Histologically, it invaded to the subserosa and was composed of both adenocarcinomatous and sarcomatous components. Adenocarcinomatous foci generally showed tubular to solid patterns and occupied the parts facing the gastric lumen, while the sarcomatous components showed a generally irregular and solid arrangement. There were transitions between the sarcomatous and carcinoma elements. In addition, carcinoma cells with a cord-like or trabecular arrangement similar to that seen in endocrine carcinoma expressed chromogranin A, and were mainly observed in an intermediate area between the adenocarcinomatous and sarcomatous foci. The sarcomatous areas were mainly composed of spindle cells and occasionally contained a sarcomatous component showing rhabdomyosarcomatous differentiation. This is an interesting case to consider how the variety of cell type appeared in such a type of tumor in the stomach.