Inducing cholesterol precipitation from pig bile with beta-cyclodextrin and cholesterol dietary supplementation

Intrahepatic cholelithiasis with gallbladder-like metaplasia of intrahepatic bile ducts associated with gallbladder agenesis in a wild boar

An unknown-aged adult female wild boar (Sus scrofa) was brought to Kyungpook National University for postmortem examination. Gross examination revealed gallbladder agenesis. Histologically, the liver was cirrhotic and had intrahepatic cholelithiasis, the choleliths were yellow, brown, gray, and black, and had coffin-lid and pyramidal appearances. Fourier-transform infrared spectroscopy analysis revealed that the components were 80% struvite and 20% calcium oxalate monohydrate. Chronic inflammatory cell infiltration was observed, with hyperplastic hepatocellular nodules characterized by large nuclei, prominent nucleoli, and scant cytoplasm with frequent binucleation, surrounded by thick fibrous septa. The epithelium of intrahepatic bile ducts that contained choleliths had undergone gallbladder-like metaplasia, which might have been induced by chronic irritation from the stones or by the accompanying chronic bacterial infection that was observed in Gram stains.

Chronic Inflammatory and Proliferative Lesions of the Gallbladder in Aged Pigs

Primary epithelial tumors of the gallbladder are rarely reported in animals. In this study, 9 aged pigs (6-12 years old) were histopathologically examined for gallbladder proliferative lesions. At necropsy, a large gallstone occupied the lumen of the gallbladder of 3 pigs. Histopathological examination revealed chronic cholecystitis in all 9 pigs, mucosal hyperplasia in 2 pigs, adenoma in 1 pig, and adenocarcinoma in 2 pigs. Bacilli were detected in the gallbladder lumen of 6 pigs by Warthin-Starry stain. Mucosal hyperplasia, adenoma, and adenocarcinoma were characterized by papillary projections of the mucosa with occasional acinar structures. Tumor invasion of the surrounding tissue was observed in the cases of adenocarcinoma. On Alcian blue and periodic acid-Schiff double-stained sections, the acinar structure of gallbladder mucosa in chronic cholecystitis and mucosal hyperplasia was stained in a mosaic pattern, indicating pyloric gland metaplasia. The results of immunohistochemistry revealed a CD10-positive epithelial brush border and mucin (MUC) 2-positive goblet cells in chronic cholecystitis, adenoma, and adenocarcinomas, indicating intestinal metaplasia. Immunoreactivity of MUC5 AC and cytokeratin 19 was weaker in adenoma and adenocarcinomas compared with the normal and hyperplastic gallbladder mucosa. The number of p53-positive nuclei and the Ki-67 index were higher in adenocarcinomas compared with benign lesions. These results suggest that chronic cholecystitis associated with gallstones and/or bacterial infections may contribute to metaplastic changes and development of gallbladder tumors in aged pigs. Alteration of mucin, cytokeratin, and p53 profiles in gallbladder proliferative lesions in pigs were similar to that in humans, suggesting a common pathogenesis in tumor development.

Cyclodextrins in Food Technology and Human Nutrition: Benefits and Limitations

Cyclodextrins are tasteless, odorless, nondigestible, noncaloric, noncariogenic saccharides, which reduce the digestion of carbohydrates and lipids. They have low glycemic index and decrease the glycemic index of the food. They are either non- or only partly digestible by the enzymes of the human gastrointestinal (GI) tract and fermented by the gut microflora. Based on these properties, cyclodextrins are dietary fibers useful for controlling the body weight and blood lipid profile. They are prebiotics, improve the intestinal microflora by selective proliferation of bifidobacteria. These antiobesity and anti-diabetic effects make them bioactive food supplements and nutraceuticals. In this review, these features are evaluated for α-, β- and γ-cyclodextrins, which are the cyclodextrin variants approved by authorities for food applications. The mechanisms behind these effects are reviewed together with the applications as solubilizers, stabilizers of dietary lipids, such as unsaturated fatty acids, phytosterols, vitamins, flavonoids, carotenoids and other nutraceuticals. The recent applications of cyclodextrins for reducing unwanted components, such as trans-fats, allergens, mycotoxins, acrylamides, bitter compounds, as well as in smart active packaging of foods are also overviewed.

Combined effect of Lactobacillus acidophilus and β-cyclodextrin on serum cholesterol in pigs

A total of twenty-four Yorkshire gilt pigs of 6-7 weeks of age were used in a 2×2 factorial experiment to determine the individual and combined effects of the inclusion of two dietary factors (cholesterol rich, 3% β-cyclodextrin (BCD) and Lactobacillus acidophilus cultures) on total cholesterol and LDL-cholesterol levels in blood serum. Pigs were assigned randomly to treatment groups (n 6). Total serum cholesterol concentrations decreased after 3 weeks in all the experimental treatment groups, including diets with BCD, L. acidophilus or both. Similar trends were observed for serum LDL-cholesterol concentrations among the experimental treatments. No statistically significant differences from the control group were observed in either total serum cholesterol or LDL-cholesterol concentrations (P<0·05) for each of the individual treatment groups: BCD or L. acidophilus. However, significant differences in total serum cholesterol concentrations were observed when comparing the combined treatment group (BCD and L. acidophilus) with the control group, which consisted of a basal diet and sterile milk. The combined treatment group exhibited 17·9% lower total serum cholesterol concentration after 3 weeks. Similar significant differences were observed when comparing the combined effect experimental group with the control group after 3 weeks. The combined treatment group exhibited 27·9% lower serum LDL-cholesterol concentrations.

Bifidobacterium animalis strain DN-173 010 hydrolyses bile salts in the gastrointestinal tract of pigs

BACKGROUND

Bile salt hydrolase (BSH) activity is widespread among ingested bifidobacteria and lactobacilli. It is sometimes considered to be beneficial because of its putative lowering effect on cholesterol absorption and sometimes considered to be deleterious because it may compromise normal fat absorption and even promote the formation of secondary cytotoxic bile acids by the resident intestinal flora. However, the true hydrolysis of bile salts in vivo by ingested living bacteria remains unexplored. The aim of the study was to examine whether or not Bifidobacterium animalis DN-173 010 (used in fermented milks), which demonstrates a BSH activity in vitro, was also active in vivo during its transit in the intestine of pigs.

METHODS

Direct measurement of total and unconjugated bile acids reabsorbed into the portal vein was done, before and after the pigs had been treated for 2 weeks with two daily doses of approximately 3.5 x 10(11) colony-forming units of living (6 pigs) or inactivated B. animalis (6 pigs).

RESULTS

None of the treatments modified the portal serum concentration of total bile acids over a 6-h postprandial period. Unconjugated bile acids represented up to 44% and 53% of total bile acids after 1 and 2 weeks of treatment with living bacteria, respectively, compared with only 25% (P < 0.05) before treatment or after 1 or 2 weeks of treatment with inactivated bacteria.

CONCLUSIONS

Living B. animalis DN-173 010 exhibited a BSH activity in the gastrointestinal tract of pigs, most probably in the small bowel. There was no sign of increased formation of secondary bile acids beyond the hydrolysis reaction.

Effects of dietary beta-cyclodextrin in hypercholesterolaemic rats

Beta-cyclodextrin is a compound that forms inclusion complexes with a variety of molecules, specially bile acids and sterols. This study examines the effects of beta-cyclodextrin on cholesterol and bile acid metabolism in hypercholesterolaemic rats. Male Wistar rats were divided into 4 groups that received during 7 weeks: control diet, 2% cholesterol diet (A), A+2.5% beta-cyclodextrin (B) and A+5% beta-cyclodextrin (C). The cholesterol-rich diet induced hepatomegaly and fatty liver and significantly reduced cholesterol, bile acid and phospholipid secretion. Addition of beta-cyclodextrin normalised biliary lipid secretion. Moreover, when compared to A, beta-cyclodextrin significantly lowered plasma phospholipid concentration (B: -21%; C: -29%) and the liver free/total cholesterol molar ratio (B: -40%; C: -38%), increased bile acid faecal output (B: +17%; C: +62%) and enhanced cholesterol 7alpha-hydroxylase activity (B:+50%; C : +100%)and mRNA levels (B: + 14%; C: +29%). 5% beta-cyclodextrin also reduced plasma triglycerides concentration (-38%). However, ALT and AST activities were significantly increased (B: +140% and +280%; C: +72% and +135%) and there was a high incidence of cell necrosis with portal inflammatory cell infiltration. Addition of beta-cyclodextrin to a cholesterol-rich diet results in a triglyceride-lowering action, enhancement of bile acid synthesis and excretion, and normalization of biliary lipid secretion, but produces a marked hepatotoxic effect.

Impaired human gallbladder lipid absorption in cholesterol gallstone disease and its effect on cholesterol solubility in bile

BACKGROUND & AIMS

The role of the gallbladder in gallstone pathogenesis is still unclear. We examined the effects of gallbladder mucosal lipid absorption on lipid composition and cholesterol crystallization in bile.

METHODS

The in vitro-isolated, intra-arterially perfused gallbladder model was used (1) to compare the absorption rates of lipids from standard bile by gallbladders obtained from 7 patients with cholesterol gallstones and 6 controls; and (2) to measure the microscopic cholesterol crystal detection time in cholesterol-enriched pig bile before and after lipid absorption by the pig gallbladder.

RESULTS

Control gallbladders, but not cholesterol gallstone gallbladders, significantly reduced cholesterol (P < 0.02) and phospholipid (P < 0.01) and increased bile salt (P < 0.01) molar percentages in bile over a 5-hour period by efficient and selective cholesterol and phospholipid absorption. A histomorphometric study of the epithelial cells showed significantly higher values for nuclear density (P < 0.01) and nuclear (P < 0.05) and cytoplasmic (P < 0.05) areas in the cholesterol gallstone than the control group. Sequential microscopy of cholesterol-enriched pig bile showed significantly shorter cholesterol filament (P < 0.01) and typical cholesterol plate (P < 0. 02) detection times before than after exposure of bile to the gallbladder lipid absorption.

CONCLUSIONS

In cholesterol gallstone disease, the human gallbladder epithelium loses its capacity to selectively and efficiently absorb cholesterol and phospholipids from bile, even if it is hyperplastic and hypertrophic. This epithelial dysfunction eliminates the positive effect that the normal gallbladder exerts on cholesterol solubility in bile and might be a pathogenetic cofactor for cholesterol gallstone formation.

Effect of beta-cyclodextrin dietary supplementation on biliary proteins and their resulting cholesterol nucleating activity in pigs

We explored the possibility that the biliary protein fraction may support part of the variation in the nucleating activity previously measured in gallbladder biles of pigs. Eighteen gallbladder aspirates freshly obtained from three dietary groups (0, 5, or 10% beta-cyclodextrin) of six pigs were chromatographed to purify their total protein fraction. Proteins were quantified, and analysed through electrophoresis and immunoblotting or enzyme-linked immunosorbent assay for albumin, and five putative effectors of cholesterol crystallisation, mucins, immunoglobulin A, 130 kDa, apolipoprotein A-I, and anionic polypeptide fraction. Each total protein fraction was also assayed for its ability to influence cholesterol precipitation, when added to supersaturated model bile. The current data provided evidence that the cholesterol crystallisation-promoting activity of biliary proteins in model biles increased with the beta-cyclodextrin dietary content. This occurred without any significant change in the total biliary protein content, but was associated with a significant decrease in the concentration of albumin and apolipoprotein A-I, resulting in changes in the overall balance of proteins in bile. Comparison of these results with the crystallisation figures previously obtained from the corresponding native biles led us to conclude that biliary proteins might influence the outcome of the crystallisation process, namely the final crystal concentration at equilibrium, but would not systematically represent a major driving force for determining the velocity of crystal formation in native bile of pigs.