Removal of cholesterol by lactobacilli via incorporation and conversion to coprostanol

Abstract

Fifteen strains of Lactobacillus and Bifidobacterium were screened based on their ability to adhere to hydrocarbons via the determination of cellular hydrophobicity. Lactobacillus acidophilus ATCC 314, L. acidophilus FTCC 0291, Lactobacillus bulgaricus FTCC 0411, L. bulgaricus FTDC 1311, and L. casei ATCC 393 showed greater hydrophobicity and, thus, were selected for examination of cholesterol-removal properties. All selected strains showed changes in cellular fatty acid compositions, especially total fatty acids and saturated and unsaturated fatty acids in the presence of cholesterol compared with those grown in the absence of cholesterol. In addition, we found that cells grown in media containing cholesterol were more resistant to sonication and enzymatic lysis compared with those grown without cholesterol. We further evaluated the location of the incorporated cholesterol via the insertion of fluorescence probes into the cellular membrane. In general, enrichment of cholesterol was found in the regions of the phospholipid tails, upper phospholipids, and polar heads of the cellular membrane phospholipid bilayer. Our results also showed that lactobacilli were able to reduce cholesterol via conversion of cholesterol to coprostanol, aided by the ability of strains to produce cholesterol reductase. Our results provided experimental evidence to strengthen the hypothesis that probiotics could remove cholesterol via the incorporation of cholesterol into the cellular membrane and conversion of cholesterol to coprostanol. The strains studied may be potential health adjunct cultures in fermented dairy products with possible in vivo hypocholesterolemic effects.

High-fat diet alters gut microbiota physiology in mice

“…The fact that a HF diet may alter cellular composition of microorganisms is suggested by in vitro studies showing that the addition of cholesterol and fatty acids to growth media alter lipid and cell membrane composition of lactic acid bacteria (Dambekodi and Gilliland, 1998;Lye et al, 2010). In the present work, we used FT-IR and Raman spectroscopy to show that a HF diet induces changes in chemical composition of the cecum and single cells as a hint for changes in bacterial physiology.…”

The effects of probiotic bacteria on glycaemic control in overweight men and women: a randomised controlled trial

“…36 Similarly, probiotic supplementation delayed the onset of glucose intolerance, 48 hyperglycaemia, and hyperinsulinaemia in fructose induced type 2 diabetic rats (26), and 49 improved long-term glycaemic control in streptozotocin-induced diabetic rats (27). The 50 glycaemic benefits of probiotics have been attributed to metabolites of these bacteria are 51 which have been shown to affecting biological signalling pathways, modulate genes involved 52 in ubiquitination and proteasomal processes, and alter autonomic nerve activity. (28)(29)(30)(31)(32)(33).…”

In vitro Treatment with Intact Cells or Cell Lysates of Lactobacillus and Spirulina Induced Lowering Effects on Induced Hypercholesteremia

“…Cholesterol may be bound to the bacterial cellular surface (Liong and Shah, 2005) or incorporated into the bacterial cellular membranes (Lye et al, 2010a) or converted into coprostanol by cholesterol reductase, which is produced by strains of lactobacilli (Lye et al, 2010b). Some bacterial species excrete bile salt hydrolase, leading to increased bile excretion in feces (Begley et al, 2006).…”