Improved analysis of bile acids in tissues and intestinal contents of rats using LC/ESI-MS

Although high-fat diet (HFD)-related dysbiosis is involved in the development of steatohepatitis, its pathophysiology especially in the small intestine remains unclear. We comprehensively investigated not only the liver pathology but also the microbiome profile, mucosal integrity and luminal environment in the small intestine of mice with HFD-induced obesity. C57BL/6J mice were fed either a normal diet or an HFD, and their small-intestinal contents were subjected to microbial 16S rDNA analysis. Intestinal mucosal permeability was evaluated by FITC-dextran assay. The levels of bile acids in the small-intestinal contents were measured by liquid chromatography/mass spectrometry. The expression of tight junction molecules, antimicrobial peptides, lipopolysaccharide and macrophage marker F4/80 in the small intestine and/or liver was examined by real-time RT-PCR and immunohistochemistry. The abundance of Lactobacillus was markedly increased and that of Clostridium was drastically decreased in the small intestine of mice fed the HFD. The level of conjugated taurocholic acid was significantly increased and those of deconjugated cholic acid/secondary bile acids were conversely decreased in the small-intestinal contents. The expression of occludin, antimicrobial Reg IIIβ/γ and IL-22 was significantly decreased in the small intestine of HFD-fed mice, and the intestinal permeability was significantly accelerated. Infiltration of lipopolysaccharide was significantly increased in not only the small-intestinal mucosa but also the liver of HFD-fed mice, and fat drops were apparently accumulated in the liver. Pathophysiological alteration of the luminal environment in the small intestine resulting from a HFD is closely associated with minimal inflammation involving the gut-liver axis through disturbance of small-intestinal mucosal integrity.

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Identification of S-acyl glutathione conjugates of bile acids in human bile by means of LC/ESI-MS

Steroids ◽

10.1016/j.steroids.2011.10.001 ◽

2011 ◽

Vol 76 (14) ◽

pp. 1609-1614 ◽

Cited By ~ 9

Author(s):

Kuniko Mitamura ◽

Naohiro Hori ◽

Takashi Iida ◽

Mitsuyoshi Suzuki ◽

Toshiaki Shimizu ◽

...

Keyword(s):

Bile Acids ◽

Human Bile ◽

Glutathione Conjugates ◽

Esi Ms

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Dietary fibre-rich oat-based products affect serum lipids, microbiota, formation of short-chain fatty acids and steroids in rats

British Journal Of Nutrition ◽

10.1079/bjn20051577 ◽

2005 ◽

Vol 94 (6) ◽

pp. 1012-1025 ◽

Cited By ~ 64

Author(s):

Barbora Drzikova ◽

Gerhard Dongowski ◽

Erich Gebhardt

Keyword(s):

Bile Acids ◽

Resistant Starch ◽

Dietary Fibre ◽

Control Diet ◽

Experimental Period ◽

Short Chain Fatty Acids ◽

Control Group ◽

Intestinal Contents ◽

Oat Flour ◽

Extrusion Technology

Wistar rats (ten per group) were fed either an oat-free control diet or a dietary fibre-rich test diet containing 500 g oat-based products/kg for 6 weeks. The oat-based products, containing 4–128 g/kg resistant starch, 30–92 g/kg β-glucan and 122–304 g/kg total dietary fibre, were oat flour extrudate, flour/Novelose (commercial resistant starch) extrudate (80:20 w/w), oat bran, bran/Novelose extrudate (80:20 w/w) and autoclaved oat flour. Serum total cholesterol decreased in the groups fed flour, flour/Novelose and bran/Novelose (P<0·05). In most of the test groups, count numbers of bifidobacteria were higher (P<0·001) and of coliforms were lower (P<0·05). The mass of the caecum walls and contents was greater in groups fed Novelose- and bran-containing diets (P<0·005). In all the test groups, pH values were lower in the intestinal contents (P<0·001), and caecal concentrations of acetate (P<0·001), propionate (P<0·05), butyrate (P<0·005) and total SCFA (P<0·001) were higher. The lowest concentrations of steroids were found in rats fed the autoclaved flour. In the other test groups, more bile acids appeared in the caecal (P<0·001) and colonic contents (P<0·005), as well as in the faeces, at week 6 (P<0·001). The highest bile acid excretion was found after feeding bran-containing diets. In the intestinal contents of all the test groups, more primary bile acids (P<0·001) appeared than in the control group. The excretion of steroids increased within the experimental period. Using extrusion technology, dietary fibre-rich oat-based products, which have beneficial physiological effects in rats, can be produced. Oat flour and bran are excellent sources for the preparation of directly edible oat products. Their nutritional properties can be further improved by the addition of resistant starch.

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