Strain-Specific Effects of Bifidobacterium longum on Hypercholesterolemic Rats and Potential Mechanisms

Hypercholesterolemia is an independent risk factor of cardiovascular disease, which is among the major causes of death worldwide. The aim of this study was to explore whether Bifidobacterium longum strains exerted intra-species differences in cholesterol-lowering effects in hypercholesterolemic rats and to investigate the potential mechanisms. SD rats underwent gavage with each B. longum strain (CCFM 1077, I3, J3 and B3) daily for 28 days. B. longum CCFM 1077 exerted the most potent cholesterol-lowering effect, followed by B. longum I3 and B3, whereas B. longum B3 had no effect in alleviating hypercholesterolemia. Divergent alleviation of different B. longum strains on hypercholesterolemia can be attributed to the differences in bile salt deconjugation ability and cholesterol assimilation ability in vitro. By 16S rRNA metagenomics analysis, the relative abundance of beneficial genus increased in the B. longum CCFM 1077 treatment group. The expression of key genes involved in cholesterol metabolism were also altered after the B. longum CCFM 1077 treatment. In conclusion, B. longum exhibits strain-specific effects in the alleviation of hypercholesterolemia, mainly due to differences in bacterial characteristics, bile salt deconjugation ability, cholesterol assimilation ability, expressions of key genes involved in cholesterol metabolism and alterations of gut microbiota.

Corrigendum to “Effects of Probiotics, Prebiotics, and Synbiotics on Hypercholesterolemia: A Review”

Cholesterol is important for both humans and animals to maintain their normal health. However, increased serum cholesterol level can cause several cardiovascular diseases. Higher cholesterol in the blood will develop a plaque in the walls of artery. Numerous pharmacological and nonpharmacological methods have been used to decrease the blood cholesterol. Various drugs have been developed to treat hypercholesterolemia, and the most common drugs include atorvastatin and rosuvastatin (statin drugs). However, prolonged usage of these drugs causes severe side effects. During the past decades, various scientists reported that the ingestion of several fermented products with probiotic bacteria decreases the serum cholesterol level. Probiotics are viable microorganisms that promote various health benefits upon consumption, while prebiotics are nondigestible food ingredients, which promote the growth of probiotic microorganisms in the human gut. The cholesterol reduction mechanism of probiotic bacteria is not well understood; however, most of the probiotic bacteria reduce the serum cholesterol level by using the bile salt deconjugation method. Herein, we review the cholesterol-reducing capability of probiotics, prebiotics, and synbiotics and use them as an alternative for cholesterol-reducing drugs which is used for hypercholesterolemia.

Screening for Cholesterol-Lowering Probiotics from Lactic Acid Bacteria Isolated from Corn Silage Based on Three Hypothesized Pathways

A total of 85 strains of lactic acid bacteria were isolated from corn silage in this study and analyzed in vitro for their cholesterol removal, NPC1L1 protein down-regulation and bile salt deconjugation ability, respectively. Nineteen strains were selected for further analysis for their probiotic potential. Finally, 3 strains showing better probiotic potential were evaluated for their cholesterol-lowering activity in hamsters. The strains showing the greater cholesterol removal and NPC1L1 protein down-regulation activity had no significant effects on serum and hepatic cholesterol levels in hamsters (p > 0.05). However, Lactobacillus plantarum CAAS 18008 (1 × 109 CFU/d) showing the greater bile salt deconjugation ability significantly reduced serum low-density lipoprotein cholesterol, total cholesterol, and hepatic total cholesterol levels by 28.8%, 21.7%, and 30.9%, respectively (p < 0.05). The cholesterol-lowering mechanism was attributed to its bile salt hydrolase activity, which enhanced daily fecal bile acid excretion levels and thereby accelerated new bile acid synthesis from cholesterol in liver. This study demonstrated that the strains showing greater cholesterol removal and NPC1L1 protein down-regulation activity in vitro hardly reveal cholesterol-lowering activity in vivo, whereas the strains showing greater bile salt deconjugation ability in vitro has large potential to decrease serum cholesterol levels in vivo.

Screening of Bile Salt Hydrolase-Active Lactic Acid Bacteria for Potential Cholesterol-Lowering Probiotic Use

.Cholesterol-lowering effect of lactic acid bacteria (LAB) with bile salt hydrolase activity is well known. In this study, 150 LAB were screened for bile salt deconjugation ability and probiotic characters. Fourteen isolates with higher bile salt deconjugation ability were initially screened out using deconjugation rate above 50% as standard. These isolates were further screened for adhesion to HT-29 cells, bile tolerance and acid resistance. Four isolates, namely Lactobacillus casei F0822, Lactobacillus casei F0422, Enterococcus faecium F0511 and Enterococcus faecium IN7.12, was finally screened out. The 4 isolates may be able to reduce serum cholesterol levels in human and thus have a potential to apply in the biomedicine field.

Investigation of Microencapsulated BSH ActiveLactobacillusin the Simulated Human GI Tract

This study investigated the use of microencapsulated bile salt hydrolase (BSH) overproducingLactobacillus plantarum80 cells for oral delivery applications using a dynamic computer-controlled model simulating the human gastrointestinal (GI) tract. Bile salt deconjugation rates for microencapsulated BSH overproducing cells were 4.87±0.28 μmol/g microcapsule/h towards glycoconjugates and 0.79±0.15 μmol/g microcapsule/h towards tauroconjugates in the simulated intestine, a significant (P<.05) increase over microencapsulated wild-type cells. Microcapsules protected the encased cells in the simulated stomach prior to intestinal release, maintaining cell viability above109 cfu/mL at pH 2.5 and 3.0 and above106 cfu/mL at pH 2.0 after 2-hour residence times. In the simulated intestine, encased cell viability was maintained above1010 cfu/mL after 3, 6, and 12-hour residence times in bile concentrations up to 1.0%. Results show that microencapsulation has potential in the oral delivery of live BSH active bacterial cells. However,in vivotesting is required.