The liver in collagen diseases: pathologic study of 160 cases with particular reference to hepatic arteritis, primary biliary cirrhosis, autoimmune hepatitis and nodular regenerative hyperplasia of the liver.

AIMS/BACKGROUND: Among patients with collagen diseases, liver enzyme abnormalities are a relatively common phenomenon. To establish the liver pathology in collagen diseases, detailed pathologic studies were performed on the hepatic diseases in many patients, including various kinds of collagen diseases. METHODS: The livers from 160 patients (120 autopsy and 40 liver biopsy patients) were examined pathologically: 73 with systemic lupus erythematosus (SLE), 32 with rheumatoid arthritis (RA), 18 with polymyositis and dermatomyositis (PM and DM), 15 with systemic sclerosis (SSc), 11 with mixed connective tissue disease (MCTD) and 11 with polyarteritis nodosa (PAN). RESULTS: Liver diseases were divided into three groups: hepatic arteritis, liver diseases associated with collagen diseases (primary biliary cirrhosis, PBC; autoimmune hepatitis, AIH; nodular regenerative hyperplasia of the liver, NRH) and other liver diseases. Hepatic arteritis presenting the features of the PAN type of necrotizing arteritis was found in 27 autopsy patients. The incidence of arteritis in autopsy patients was 100% in PAN and 8.3-25% in other collagen diseases. Primary biliary cirrhosis was observed in 9 patients, 7 of whom (3 with SSc, 2 with RA, 1 with PM and DM, and 1 with MCTD) had antimitochondrial antibodies (AMA)-positive PBC, and 2 SLE patients had AMA-negative PBC. Three patients (2 with SLE and 1 with MCTD) were diagnosed clinicopathologically as having AIH. However, 3 patients (1 with SLE, 1 with MCTD and 1 with PM and DM) with clinical, biochemical and serologic data indicating probable AIH were excluded from the group with AIH association because of the liver histology (no characteristic features of AIH) and clinical course. These results indicated that data without histologic assessments of the liver are not adequate for diagnosing AIH in collagen diseases. Nodular regenerative hyperplasia of the liver was observed in 7 patients (5 with SLE, 1 with SSc and 1 with PAN). CONCLUSION: The present study offers data that are useful for the diagnosis and treatment of patients with collagen diseases and liver abnormalities.

Detection of IgA, IgM, and IgG subclasses of anti-M2 antibody by immunoblotting in autoimmune cholangitis: is autoimmune cholangitis an early stage of primary biliary cirrhosis?

Autoimmune cholangitis (AIC) has been proposed as a distinct disease entity from primary biliary cirrhosis (PBC), without antimitochondrial antibody (AMA) and anti-M2 antibody but with a high titer of antinuclear antibody (ANA) in the serum. However, negativity for AMA and anti-M2 antibody was determined by different methods in different studies. We hypothesized that anti-M2 antibody negativity in AIC resulted from methodological differences, including selection of the immunoglobulin subclass of the autoantibody. Twenty-three patients compatible with AIC whose serum tested negative for AMA and positive for ANA (> or = 1:80) were compared with 71 AMA-positive PBC patients. Laboratory findings, histology, and the pattern of anti-M2 antibody assessed by immunoblotting were compared. Alkaline phosphatase, total bilirubin, total cholesterol, and IgM values were lower in patients with AIC (P < 0.05, 0.01, respectively). Anti-smooth muscle antibody was detected more frequently in patients with AIC (P < 0.01). However, anti-M2 antibody was detected using immunoblotting not only in PBC but also in AIC cases. IgA class alone, IgM class alone, or both IgA and IgM classes of anti-M2 antibody were detected in 13%, 17%, and 22% of AIC patients, respectively, whereas they were not detected in PBC patients (P < 0.05, P < 0.01, P < 0.01). IgG class anti-M2 was detected in all patients with PBC, whereas it was detected in 48% of patients with AIC (P < 0.01). Histological evaluation showed that the early stages of disease were found more frequently in AIC (78%) than in PBC patients (39%) (P < 0.01). Anti-M2 antibody was detected by immunoblotting in all AIC patients. Hence, AIC is not a distinct disease from PBC. For diagnosing AIC and/or PBC, anti-M2 antibody should be examined by the immunoblotting assay to detect not only IgG but also IgA and IgM subclasses.

Immunological study of anti-M2 in antimitochondrial antibody-negative primary biliary cirrhosis.

We investigated the specificity of various autoantibodies in antimitochondrial antibody (AMA)-negative patients with primary biliary cirrhosis (PBC). We examined sera from 144 patients with PBC, 17 of whom were AMA negative by indirect immunofluorescence. The AMA-negative group showed a significantly higher positivity for smooth muscle antibody, but not for antinuclear antibody, as compared with the AMA-positive group. IgG class anti-PDH by enzyme-linked immunosorbent assay (ELISA) were detected in 13% of the AMA-negative group. However, all PBC patients showed positive IgG, IgA, and/or IgM class anti-M2 to the four M2 proteins by immunoblotting. These results suggest that the detection of IgG and IgM class anti-PDH and that of antibodies to the four M2 proteins increases the positivity of this ELISA method, and that detection of IgG, IgA, and IgM class anti-M2 to the four M2 proteins by immunoblotting is useful in diagnosing AMA-negative patients with PBC.

Different features of Ca2+ oscillations in differentiated and undifferentiated hepatocyte doublets.

Cytosolic free Ca2+ ([Ca2+]i) oscillations are postulated to play a critical role in cellular proliferation. By using doublets of normal rats (NR) and those 18 hours after two-thirds hepatectomy (PHR), we investigated cytosolic free Ca2+ ([Ca2+]i) responses in liver regeneration. Normal rat hepatocyte doublets that retain their bile canaliculi are polarized and well differentiated. PHR doublets, which also retain their bile canaliculi, were characterized as undifferentiated by (1) decreased canalicular secretion of fluorescein-isothiocyanate-labeled glycocholate; (2) increased labeling index of hepatocytes in BrdU staining (approximately 30%); and (3) impaired transfer of fluorescent dye injected into one cell of the pair to the other. Addition of phenylephrine to NR and PHR doublets in the presence of extracellular Ca2+ resulted in [Ca2+]i oscillations or a nonoscillatory-sustained increase in [Ca2+]i followed by a gradual return to the baseline. Extracellular Ca2+ was not required for [Ca2+]i oscillations but was necessary for a sustained increase in [Ca2+]i. Simultaneous addition of prazosin, alpha 1-receptor blocker, to doublets immediately abolished these [Ca2+]i responses. The [Ca2+]i level in each of the adjacent cells was synchronous in sustained increase in [Ca2+]i but asynchronous in [Ca2+]i oscillations. As the phenylephrine concentration was increased (1 to 100 mumol/L), oscillations were replaced by a sustained increase in [Ca2+]i in NR doublets. In contrast, in PHR doublets, oscillations remained, whereas the frequency of oscillations increased in a dose-dependent manner. These results indicate that the mechanisms of phenylephrine-evoked [Ca2+]i responses are different in differentiated and undifferentiated doublets and that the frequency modulation of [Ca2+]i oscillations may be involved in the intracellular signal transduction in the cellular proliferation process during liver regeneration.

Effect of nicotine in migration and proliferation of rabbit gastric mucosal cells in a culture cell model.

The aim of this study was to assess the effects of nicotine on the gastric epithelial restoration using primary cultured rabbit gastric mucosal cell model. Confluent monolayer mucosal cell sheets consisting of mainly mucous cells were wounded using a rotating silicon tip. The process of restoration was monitored, and the size of wound was measured and analysed quantitatively. Artificial wounds recovered in 36 h in controls. The nicotine treatment (10(-5), 10(-4) and 10(-3) mol/L) did not cause any effects on the process of wound repair. Bromodeoxyuridine (BrdU) positive cells appeared around the wound 24-36 h after injury and then disappeared after the complete repair in controls and also in nicotine-treated groups. However, in the morphological observation, numerous vacuoles were detected in parietal cells of nicotine-treated groups. This effect of nicotine was reversible by removing nicotine from the medium. Present data suggest that nicotine has no direct effects on the mucosal restoration but might have an effect on the structure and function of parietal cells.

Immunoreactivity to M2 proteins in antimitochondrial antibody-negative patients with primary biliary cirrhosis.

Although antimitochondrial auto-antibodies are characteristically present in the serum of patients with primary biliary cirrhosis (PBC), there is a discrepancy between the positivity for antimitochondrial antibody (AMA) and that for anti-M2 auto-antibody. In an attempt to explain the discrepancy, this study investigates the relationship between the AMA titre, determined by indirect immunofluorescence, and immunoreactivity to four inner mitochondrial membrane proteins (M2 proteins) with molecular weights of 70, 50, 47, and 40 kDa in 129 patients with PBC. Antimitochondrial antibody positivity was identified in 114 (88%) of 129 patients with clinically and histologically confirmed PBC. There were no significant differences between the AMA-negative and AMA-positive groups in clinical characteristics or histologically determined disease stage. Immunoblot analysis showed that all patients had anti-M2 auto-antibodies to one or more of the four M2 proteins. Nine (60%) of the 15 AMA-negative patients had antibodies to only one M2 protein (either 70 or 47 kDa). In contrast, 34 (53%) of the 64 patients with high AMA titres (> or = 1:320) had antibodies to all four M2 proteins. There was a significant rank correlation between the AMA titre and the number of antibodies to M2 proteins (P < 0.01). These findings indicate that the AMA titre is not influenced by the immunogenicity of M2 proteins but by the number of M2 proteins that elicit an antibody response and that decreased immunoreactivity to M2 proteins may induce AMA negativity in PBC serum samples.

Marked retention of indocyanine green and sulfobromophthalein with chronic persistent hepatitis.

A hepatitis B virus (HBV) carrier with marked retention of indocyanine green (ICG) and sulfobromophthalein (BSP) was admitted to our hospital for assessment of liver function. On admission, he was asymptomatic and blood chemistry tests showed normal values for transaminases and bilirubin. Serum hepatitis B surface antigen (HBsAg) and antibody to hepatitis B e antigen (anti-HBe) were positive. A history of drug abuse or alcoholism was denied. Dye excretion tests revealed marked retention of ICG (R15 = 70%) and BSP (R45 = 23%). Histopathological examination of a liver biopsy specimen obtained during laparoscopic observation showed chronic persistent hepatitis (CPH). Familial research of the patient failed to prove the existence of dye excretory defect in his siblings. Usual cases of CPH due to continuous HBV infection do not show such severe disturbance of organic anion transport. This pattern of the dye excretory defect with CPH has not been reported. Although the relationship between this dye excretory defect and HBV infection is unclear, the existence of the constitutional dye excretory defect due to abnormal organic anion transport in the liver might be considered.

Pertussis toxin-induced redistribution of cortical actomyosin and inhibition of phagocytosis in rat Kupffer cells.

The mechanism of phagocytosis by Kupffer cells has been shown to be related to the Ca(2+)-calmodulin and the actomyosin systems. However the role of the transmembrane signal transmitter, G-protein, is still unknown. In this study, a quantitative evaluation of phagocytosis by Kupffer cells of rats in culture and the effects of pertussis toxin, a G-protein inhibitor, on the phagocytic function and morphology of Kupffer cells were investigated. Pertussis toxin inhibited phagocytosis of Kupffer cells with dysfunction of the actomyosin system. The inhibitory effects of pertussis toxin suggest that G-protein may be involved in the mechanism of transmembrane signalling in phagocytosis by Kupffer cells.