The different effects of deoxynivalenol (DON) on intestinal barrier and stem cells by its route of exposure remain less known. We explored the toxic effects of DON on intestinal barrier functions and stem cells after DON microinjection (luminal exposure) or addition to a culture medium (basolateral exposure) using three-dimensional mouse intestinal organoids (enteroids). The influx test using fluorescein-labeled dextran showed that basolateral DON exposure (1 micromolar (µM) disrupted intestinal barrier functions in enteroids compared with luminal DON exposure at the same concentration. Moreover, an immunofluorescence experiment of intestinal epithelial proteins, such as E-cadherin, claudin, zonula occludens-1 (ZO-1), and occludin, exhibited that only basolateral DON exposure broke down intestinal epithelial integrity. A time-lapse analysis using enteroids from leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5)-enhanced green fluorescence protein (EGFP) transgenic mice and 5-ethynyl-2-deoxyuridine (EdU) assay indicated that only the basolateral DON exposure, but not luminal DON exposure, suppressed Lgr5+ stem cell count and proliferative cell ratio, respectively. These results revealed that basolateral DON exposure has larger impacts on intestinal barrier function and stem cells than luminal DON exposure. This is the first report that DON had different impacts on intestinal stem cells depending on the administration route. In addition, RNA sequencing analysis showed different expression of genes among enteroids after basolateral and luminal DON exposure.

CD44 expression in the bile duct epithelium is related to hepatic fibrosis in nonalcoholic steatohepatitis rats

Nonalcoholic steatohepatitis (NASH) is a progressive liver disease, and some patients develop hepatic cirrhosis/carcinoma. Animal models play key roles in the development of new therapies for NASH. In this study, the pharmacological effects of metformin and pioglitazone were investigated in female Spontaneously Diabetic Torii (SDT) fatty rats to verify the utility of this model. The anti-diabetic drugs were administered to SDT fatty rats fed a cholesterol-enriched diet from 4 to 25 weeks, and changes in food intake, body weight, and blood chemistry parameters were evaluated every 4 weeks. The hepatic lipid content, mRNA expression in relation to lipid synthesis, inflammation, and fibrosis, and histopathological analyses were performed at 25 weeks. Pioglitazone improved hyperglycemia, hyperlipidemia, and abnormalities in hepatic parameters. The insulin levels were lower than those in the control rats before 16 weeks. Plasma glucose levels in the metformin-treated rats were lower than those in the control rats, and plasma alanine aminotransferase levels temporarily decreased. The lipid content and some mRNA expression in relation to fibrosis in the liver decreased with pioglitazone treatment, and the mRNA expression of microsomal triglyceride transfer protein increased. Hepatic fibrosis observed in the SDT fatty rats improved with pioglitazone treatment; however, the effect with metformin treatment was partial. These results in both drugs are in line with results in the human study, suggesting that the SDT fatty rat is useful for developing new anti-NASH drugs that show potential to regulate glucose/lipid metabolism.

Nonalcoholic steatohepatitis (NASH) is an aggressive form of nonalcoholic fatty liver disease that presents with steatosis, inflammation, and fibrosis and can progress to cirrhosis and cancer. Thus, methods for controlling this lifestyle-related disease are urgently needed. An extract of Siraitia grosvenorii (Luo-Han-Guo) (luohanguo extract (LE)) is widely used as a sweetener; its major bioactive constituents, mogrosides, have shown anti-oxidative and anti-inflammatory properties, exerting multiple pharmacological effects in various disorders. In the present study, we investigated the effects of LE on NASH induced in mice fed a choline-deficient, methionine-lowered, L-amino acid-defined, high-fat diet without trans fatty acids (CDAA-HF-T(−)). Mice were fed with CDAA-HF-T(−) and drinking water containing LE at concentrations of 0%, 0.2%, 0.6%, and 2% for 28 weeks. Our results showed that LE was not toxic under the experimental conditions evaluated. In the liver of mice fed CDAA-HF-T(−), LE did not affect steatosis or early phase events from macrophage recruitment to hepatocyte death but inhibited late phase events, the progression of inflammation, and fibrosis (mechanisms independent of transforming growth factor-β signaling). Sweeteners with beneficial biological functions, such as LE, may be useful for controlling lifestyle-related diseases, such as NASH, and promoting human health.

Metabolic diseases including nonalcoholic steatohepatitis develop due to various environmental factors. In particular, the westernization of food is closely related to the development of these diseases. In this study, we investigated pathophysiological changes in the livers of Zucker fatty (ZF) rats induced by feeding Western diets. Male ZF rats were fed a sucrose/fat/cholesterol-enriched diet (Western diet, WD) or standard diet (SD) for 18 weeks, from 7 to 25 weeks of age. Body weight, food intake, and biochemical parameters were periodically measured, histopathological analyses were performed at 25 weeks, and mRNA expression in the liver was determined. ZF rats fed the WD (ZF-WD rats) developed obesity, hyperinsulinemia, hyperglycemia, and hyperlipidemia, and their alanine aminotransferase and aspartate aminotransferase levels increased compared with those of ZF rats fed the SD (ZF-SD rats). Hepatic lesions including fibrosis and necrosis were observed in the ZF-WD rats at 25 weeks; however, fibrosis and necrosis were not observed in the ZF-SD rats. Oxidative stress markers also increased in the livers of ZF-WD rats. Hepatic mRNA expression related to inflammation and fibrosis increased in the ZF-WD rats; however, mRNA expression related to lipid synthesis decreased. Microsomal triglyceride transfer protein mRNA levels in the ZF-WD rats also decreased. In Zucker lean rats fed the WD, similar changes were observed in the liver; however, the hepatic changes were not serious compared with ZF-WD rats. In conclusion, hepatic lesions, such as inflammation, fibrosis, and necrosis, were observed in the ZF-WD rats. The sucrose/fat/cholesterol-enriched diet induced significant lipotoxicity in the livers of animals in this insulin-resistant model.