Determination of underivatised sterols and bile acid trimethyl silyl ether methyl esters by gas chromatography–mass spectrometry–single ion monitoring in faeces

Keller, Sylvia; Jahreis, Gerhard

doi:10.1016/j.jchromb.2004.09.046

Cited by 93 publications

(89 citation statements)

References 38 publications

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“…To 500 mg of the pulverised lyophilisate, 3.48 ml distilled water were added (fecal water dilution factor 3), shaken at 37°C for 1 hr and centrifuged at 20,000 g for 20 min. The bile acid (BA) analysis was carried out as described previously, 18 with minor modifications. In short, 800 ll of the water extract were hydrolysed with ethanolic NaOH and the neutral sterols were extracted with cyclohexane.…”

Section: Determination Of the Bile Acid Concentration In The Fecal Watermentioning

confidence: 99%

Prevention of colitis‐associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid

Loddenkemper

Keller

Hanski

et al. 2006

Intl Journal of Cancer

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Bile acids in the intestinal lumen contribute to the homeostatic regulation of proliferation and death of the colonic epithelial cells: Deoxycholic acid (DCA) appears to enhance and ursodeoxycholic acid (UDCA) to attenuate the process of chemically induced carcinogenesis. We studied the effects of UDCA on colitis-related colorectal carcinogenesis. Three groups of 25 mice were given 0.7% dextran sulphate in drinking water for 7 days and pure water for 10 days and were fed a standard diet containing double iron concentration. In 2 groups, the diet was supplemented with 0.2% cholic acid (CA), the precursor of DCA, or with 0.4% UDCA. After 15 cycles, the histology, the expression of MUC2, b-catenin, p27 and p16 and the fecal water concentration of DCA and UDCA were investigated. All animals showed colitis with similar severity and histologic as well as immunophenotypic alterations, resembling those of human colitis. Among the animals fed the nonsupplemented diet, 46% developed colorectal adenocarcinomas and 54% anal-rectal squamous cell carcinomas. The prevalence of dysplasia and carcinomas did not change significantly in the animals given CA. Among the mice fed with UDCA, none developed adenocarcinomas and 20% squamous carcinomas. Dysplastic lesions were found in 88%, 67% and 40% of each group, respectively. The prevalence of dysplasia as well as of carcinoma showed an inverse relationship to the UDCA concentration in the fecal water. These data indicate that UDCA suppresses colitis-associated carcinogenesis. This model is suitable for investigation of the mechanism of the anticarcinogenic effect of UDCA in vivo. ' 2005 Wiley-Liss, Inc.Key words: murine colitis; colon carcinogenesis; DSS colitis; ursodeoxycholic acid Ulcerative colitis (UC) in patients and in experimental animals is associated with a high risk of intraepithelial neoplasia and colonic carcinoma. The cumulative risk for colorectal cancer in a patient with UC is 2% at 10 years, 8% at 20 years and 18% at 30 years of disease duration. 1 Since the occurrence of dysplasia can be a strong indication for prophylactic proctocolectomy, 2 the inhibition or slowing down of the colitis-associated carcinogenesis would essentially reduce the number of necessary operations.Factors contributing to colon carcinogenesis are high epithelial proliferation rate in the inflamed region and the resulting increased accumulation of mutations as well as the disturbed regulation of cell death and proliferation. Intestinal bile acids contribute to the homeostatic regulation of proliferation and apoptosis of the colonic epithelium. Deoxycholic acid (DCA), whose fecal water concentration in patients with colitis is increased, 3 stimulates the proliferation of the colonic epithelial cells 4 and promotes colon carcinogenesis in an azoxymethane (AOM) rat model. 5 The addition of ursodeoxycholic acid (UDCA) to the diet decreases the prevalence of AOM-induced rat colonic tumors 6 as well as the prevalence of tumors in MIN mice. 7 These data indicate that DCA enhances the chemical colo...

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Section: Determination Of the Bile Acid Concentration In The Fecal Watermentioning

confidence: 99%

Prevention of colitis‐associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid

Loddenkemper

Keller

Hanski

et al. 2006

Intl Journal of Cancer

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“…Intermediate products (4-cholesten-3-one and 9 coprostanone) were occasionally observed, suggesting an indirect pathway for cholesterol to coprostanol conversion (KELLER & JAHREIS, 2004). Our work shows the incidence of sterols of animal and plant origin in the faecal samples of vegetarians and omnivores.…”

Section: Detection Of Faecal Sterolsmentioning

confidence: 55%

“…Individual stools were lyophilized and then stored frozen at −20 °C until analysis. Faecal sterols were extracted with cyclohexane, reconstituted in 500 μl decane, and without further derivatization these were injected in GC-MS in duplicate described by KELLER and JAHREIS (2004).…”

Section: Analysis Of Faecal Sterolsmentioning

confidence: 99%

Differences in gut microbiota activity (antimicrobials, potential mutagens, and sterols) according to diet

Olejníková¹,

Kaszonyi²,

Šimkovič³

et al. 2017

Acta Alimentaria

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The human endogenous intestinal microbiota is an essential "organ" in providing nourishment, regulating epithelial development, and instructing innate immunity. Even though lots of scientists have evaluated the content of gut microbiota from various points of view, we examined the content of intestinal microbes in the group of healthy middle aged volunteers (40-60) form Slovakia. We have compared faecal cultivable microbiota of vegetarians and omnivores. We have found that the composition of the human microbiota is fairly stable, and it seems that the major microbial groups on species level that dominate the human intestine are conserved in all individuals regardless of dietary habits. Beside the microbial content we have examined the faecal samples also for the presence of antimicrobial active compounds, potential mutagens, and faecal sterols.Keywords: intestinal microbiota, dietary habits, antimicrobial active metabolites, potential mutagenic compounds, faecal sterolsThe composition of human intestinal microbiota in the population was fi rst studied by METCHNIKOFF at the beginning of the last century (1903, 1907). Since that time, the composition of intestinal microbiota and its impact on human health became the research subject of several scientifi c groups worldwide. According to the microbial lifestyle, most cultivable intestinal microorganisms are anaerobes or facultative anaerobes (STEPHEN & CUMMINGS, 1980;SEARS, 2005). The compositions of microbiota rely on several factors, such as host diet, colonization history, and immune status. Microbial composition dramatically changes in the course of life (SEGAL & BLASER, 2014). Changes in the colon during aging may be caused by the decreasing resistance of autochthone bacteria to colonization by other bacteria. The number of anaerobic bacteria is increasing with increasing age. The genus Eubacterium is one of the arising species. The resident gut microbiota mediates metabolic effects, such as the syntheses of vitamins like biotin and folate, as well as absorption of ions including magnesium, calcium, and iron, and contributes to the lipid metabolism (O'HARA & SHANAHAN, 2006). Intestinal microbiota has * To whom correspondence should be addressed. Phone: +421259325528; e-mail: petra.olejnikova@gmail.comThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium for non-commercial purposes, provided the original author and source are credited.

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“…During the last decade 12 human intervention studies were carried out determining different nutritional influences on the faecal sterol excretion (for example Keller and Jahreis, 2004;Ditscheid et al, 2005;Keller et al, 2008). In each study a few subjects were found with an inverse faecal neutral sterol pattern, that is the intestinal cholesterol was metabolized only to a small amount to coprostanol and coprostanone by the colonic microflora.…”

mentioning

confidence: 99%

“…The pH value was not recorded in three studies with 46 subjects. Sterols were analyzed as described previously (Keller and Jahreis, 2004). The total sterol amounts were defined as the sum of the concentrations of cholesterol, coprostanol, coprostanone, cholestanol and cholestanone.…”

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confidence: 99%

Faecal varieties between high- and low-converters of cholesterol

Keller

2009

Eur J Clin Nutr

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Background: Analyzing faecal sterol concentrations in humans, subjects with a strongly decreased faecal cholesterol conversion were identified. The reasons and outcomes of this phenomenon have not been sufficiently investigated because of the complexity of the host-microflora interactions. Subjects/Methods: To evaluate differences between cholesterol high and low converters, the sterol excretion and faeces attributes of 320 healthy subjects (213 women, 107 men) were analyzed. Two different cut-off levels classifying cholesterol high and low converters were tested (level 1: conversion rate o30%; level 2: 50th percentile). Results:In both test models the faeces attributes differ significantly in a lower pH value and a lower faecal dry matter of the low converters in comparison with the high converters. Conclusions: These findings in faeces may reflect the conditions in the colon and can be a reason for the decreased bacterial growth and/or activity of cholesterol-reducing bacteria in the colonic microflora.

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Determination of underivatised sterols and bile acid trimethyl silyl ether methyl esters by gas chromatography–mass spectrometry–single ion monitoring in faeces

Cited by 93 publications

References 38 publications

Prevention of colitis‐associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid

Prevention of colitis‐associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid

Differences in gut microbiota activity (antimicrobials, potential mutagens, and sterols) according to diet

Faecal varieties between high- and low-converters of cholesterol

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