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Diverse effects of oats on cholesterol metabolism in C57BL/6 mice correlate with expression of hepatic bile acid-producing enzymes.

Andersson, Kristina E LU ; Axling, Ulrika LU ; Xu, Jie LU ; Swärd, Karl LU ; Ahrné, Siv LU ; Molin, Göran LU ; Holm, Cecilia LU and Hellstrand, Per LU (2013) In European Journal of Nutrition 52(7). p.1755-1769
Abstract
PURPOSE: We previously reported that two substrains of C57BL/6 mice respond differently to oats with respect to reduction in plasma cholesterol. Analysis of this difference might offer clues to mechanisms behind the cholesterol-lowering effect of oats. Here, we address the possible roles of hepatic steroid metabolism and the intestinal microbiota in this respect. METHODS: Female C57BL/6 mice were fed an atherogenic diet with oat bran (27 %) or control fibres for 4 weeks. RESULTS: C57BL/6 NCrl mice responded to oat bran with 19 ± 1 % (P < 0.001) lower plasma cholesterol, 40 ± 5 % (P < 0.01) higher excretion of bile acids and increased expression of the bile acid-producing hepatic enzymes CYP7A1 and CYP8B1, but none of these effects... (More)
PURPOSE: We previously reported that two substrains of C57BL/6 mice respond differently to oats with respect to reduction in plasma cholesterol. Analysis of this difference might offer clues to mechanisms behind the cholesterol-lowering effect of oats. Here, we address the possible roles of hepatic steroid metabolism and the intestinal microbiota in this respect. METHODS: Female C57BL/6 mice were fed an atherogenic diet with oat bran (27 %) or control fibres for 4 weeks. RESULTS: C57BL/6 NCrl mice responded to oat bran with 19 ± 1 % (P < 0.001) lower plasma cholesterol, 40 ± 5 % (P < 0.01) higher excretion of bile acids and increased expression of the bile acid-producing hepatic enzymes CYP7A1 and CYP8B1, but none of these effects were found in C57BL/6JBomTac mice. However, on control diet, C57BL/6JBomTac had tenfold higher expression of CYP7A1 and levels of hepatic cholesterol esters than C57BL/6NCrl mice. Plasma levels of fructosamine indicated improved glycemic control by oat bran in C57BL/6NCrl but not in C57BL/6JBomTac. C57BL/6JBomTac had higher intestinal microbiota diversity, but lower numbers of Enterobacteriaceae, Akkermansia and Bacteroides Fragilis than C57BL/6NCrl mice. Oat bran increased bacterial numbers in both substrains. Microbiota diversity was reduced by oats in C57BL/6JBomTac, but unaffected in C57BL/6NCrl. CONCLUSIONS: Our data do not support a connection between altered microbiota diversity and reduced plasma cholesterol, but the bacterial composition in the intestine may influence the effects of added fibres. The cholesterol-lowering properties of oats involve increased production of bile acids via the classical pathway with up-regulation of CYP7A1 and CYP8B1. Altered cholesterol or bile acid metabolism may interfere with the potential of oats to reduce plasma cholesterol. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
European Journal of Nutrition
volume
52
issue
7
pages
1755 - 1769
publisher
Springer
external identifiers
  • wos:000324833000007
  • pmid:23262749
  • scopus:84885482587
ISSN
1436-6215
DOI
10.1007/s00394-012-0479-1
language
English
LU publication?
yes
id
9f3de318-d931-49cb-81d9-10415943eba7 (old id 3346928)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/23262749?dopt=Abstract
date added to LUP
2013-01-02 12:48:17
date last changed
2019-03-27 01:05:40
@article{9f3de318-d931-49cb-81d9-10415943eba7,
  abstract     = {PURPOSE: We previously reported that two substrains of C57BL/6 mice respond differently to oats with respect to reduction in plasma cholesterol. Analysis of this difference might offer clues to mechanisms behind the cholesterol-lowering effect of oats. Here, we address the possible roles of hepatic steroid metabolism and the intestinal microbiota in this respect. METHODS: Female C57BL/6 mice were fed an atherogenic diet with oat bran (27 %) or control fibres for 4 weeks. RESULTS: C57BL/6 NCrl mice responded to oat bran with 19 ± 1 % (P &lt; 0.001) lower plasma cholesterol, 40 ± 5 % (P &lt; 0.01) higher excretion of bile acids and increased expression of the bile acid-producing hepatic enzymes CYP7A1 and CYP8B1, but none of these effects were found in C57BL/6JBomTac mice. However, on control diet, C57BL/6JBomTac had tenfold higher expression of CYP7A1 and levels of hepatic cholesterol esters than C57BL/6NCrl mice. Plasma levels of fructosamine indicated improved glycemic control by oat bran in C57BL/6NCrl but not in C57BL/6JBomTac. C57BL/6JBomTac had higher intestinal microbiota diversity, but lower numbers of Enterobacteriaceae, Akkermansia and Bacteroides Fragilis than C57BL/6NCrl mice. Oat bran increased bacterial numbers in both substrains. Microbiota diversity was reduced by oats in C57BL/6JBomTac, but unaffected in C57BL/6NCrl. CONCLUSIONS: Our data do not support a connection between altered microbiota diversity and reduced plasma cholesterol, but the bacterial composition in the intestine may influence the effects of added fibres. The cholesterol-lowering properties of oats involve increased production of bile acids via the classical pathway with up-regulation of CYP7A1 and CYP8B1. Altered cholesterol or bile acid metabolism may interfere with the potential of oats to reduce plasma cholesterol.},
  author       = {Andersson, Kristina E and Axling, Ulrika and Xu, Jie and Swärd, Karl and Ahrné, Siv and Molin, Göran and Holm, Cecilia and Hellstrand, Per},
  issn         = {1436-6215},
  language     = {eng},
  number       = {7},
  pages        = {1755--1769},
  publisher    = {Springer},
  series       = {European Journal of Nutrition},
  title        = {Diverse effects of oats on cholesterol metabolism in C57BL/6 mice correlate with expression of hepatic bile acid-producing enzymes.},
  url          = {http://dx.doi.org/10.1007/s00394-012-0479-1},
  volume       = {52},
  year         = {2013},
}