Hiromichi Tsunashima

Splenic lymph follicles generate immunoglobulin M-producing B cells in primary biliary cirrhosis

To reveal the site of immunoglobulin (Ig)M production in primary biliary cirrhosis (PBC) we performed immunohistochemical analysis on spleens collected from patients with PBC.

Fructo-oligosaccharides and intestinal barrier function in a methionine–choline-deficient mouse model of nonalcoholic steatohepatitis

Impairments in intestinal barrier function, epithelial mucins, and tight junction proteins have been reported to be associated with nonalcoholic steatohepatitis. Prebiotic fructo-oligosaccharides restore balance in the gastrointestinal microbiome. This study was conducted to determine the effects of dietary fructo-oligosaccharides on intestinal barrier function and steatohepatitis in methionine–choline-deficient mice. Three groups of 12-week-old male C57BL/6J mice were studied for 3 weeks; specifically, mice were fed a methionine–choline-deficient diet, a methionine–choline-deficient diet plus 5% fructo-oligosaccharides in water, or a normal control diet. Fecal bacteria, short-chain fatty acids, and immunoglobulin A (IgA) levels were investigated. Histological and immunohistochemical examinations were performed using mice livers for CD14 and Toll-like receptor-4 (TLR4) expression and intestinal tissue samples for IgA and zonula occludens-1 expression in epithelial tight junctions. The methionine–choline-deficient mice administered 5% fructo-oligosaccharides maintained a normal gastrointestinal microbiome, whereas methionine–choline-deficient mice without prebiotic supplementation displayed increases in Clostridium cluster XI and subcluster XIVa populations and a reduction in Lactobacillales spp. counts. Methionine–choline-deficient mice given 5% fructo-oligosaccharides exhibited significantly decreased hepatic steatosis (p = 0.003), decreased liver inflammation (p = 0.005), a decreased proportion of CD14-positive Kupffer cells (p = 0.01), decreased expression of TLR4 (p = 0.04), and increases in fecal short-chain fatty acid and IgA concentrations (p < 0.04) compared with the findings in methionine–choline-deficient mice that were not administered this prebiotic. This study illustrated that in the methionine–choline-deficient mouse model, dietary fructo-oligosaccharides can restore normal gastrointestinal microflora and normal intestinal epithelial barrier function, and decrease steatohepatitis. The findings support the role of prebiotics, such as fructo-oligosaccharides, in maintaining a normal gastrointestinal microbiome; they also support the need for further studies on preventing or treating nonalcoholic steatohepatitis using dietary fructo-oligosaccharides.

Accumulated myeloid-derived suppressor cells demonstrate distinct phenotypes and functions in two non-alcoholic steatohepatitis mouse models

BACKGROUND To examine the steady state of hepatic myeloid-derived suppressor cells (MDSCs) and the lipid accumulation and inflammation-related changes in these cells, we analyzed the presence and functions of hepatic MDSCs in the following two non-alcoholic steatohepatitis (NASH) mouse models. METHODS Monosodium glutamate (MSG) model; MSG was subcutaneously injected into neonatal male C57BL/6J mice that were fed with normal diet up to 18 weeks of age. Methionine/choline-deficient diet (MCD) model; 16-week-old male C57BL/6J mice were fed with an MCD for 2 weeks. Those hepatic MDSCs were evaluated by flow cytometry and immunohistochemically. RESULTS Both MSG and MCD mice exhibited greater numbers of hepatic lipid droplets than 18-week-old male control mice. Hepatocellular ballooning was obvious in MSG, whereas inflammatory cell infiltration were apparent in MCD mice. CD11b, CD115, and Gr-1-positive hepatic MDSCs were increased in both models but higher in MCD mice, and demonstrated higher expression of an M2 macrophage marker CD206 mean fluorescence intensity (MFI) in MSG compared to MCD mice. Degree of reactive oxygen species production was evaluated using the DCFDA MFI values, which were significantly elevated in hepatic MDSCs from MCD mice. MSG mouse livers demonstrated Gr-1 positive cell accumulation around lipid droplets, mimicking crown-like structures in adipose tissues. In contrast, hepatic Gr-1 positive cells were primarily located in inflammatory cell aggregates in MCD mice. CONCLUSIONS These results suggest that hepatic fatty changes promote MDSC accumulation, and inflammatory changes induce phenotypic and functional alteration in hepatic MDSCs in NASH mouse models.

Serological and Histological Examination of a Nonalcoholic Steatohepatitis Mouse Model Created via the Administration of Monosodium Glutamate

The administration of monosodium glutamate (MSG) to mice induces hepatic steatosis and inflammation. In this study, we investigated the metabolic features of MSG-treated mice and the histological changes that occur in their livers and adipose tissue. MSG mice were prepared by subcutaneously injecting MSG into newborn C57BL/6J male mice. The control mice were subcutaneously injected with saline. Another group of mice was fed a methionine- and choline-deficient diet (MCD). Compared with the control mice, the MSG mice had higher serum levels of insulin and cholesterol than the control mice, whereas the opposite was true for the MCD mice. Microvesicular steatosis and inflammatory cell infiltration were detected in both the MSG and MCD mouse livers. Enlarged adipocytes and crown-like structures were observed in the epididymal fat of the MSG mice, whereas neither of these features was seen in the MCD mice. Flow cytometric analysis revealed increased frequencies of monocytes and M1 macrophages in the livers and epididymal fat tissue of the MSG mice, respectively. The MSG mice exhibited the characteristic liver histopathology of nonalcoholic steatohepatitis (NASH) as well as metabolic syndrome-like features, which suggested that MSG mice are a better model of human NASH than MCD mice.