| Cardiovascular disease has one of the highest global incidences and mortality rates.China is the country with the highest number of deaths from cardiovascular disease in the world.Atherosclerosis is the main cause of cardiovascular disease,and hypercholesterolemia and hyperlipidemia are the main risk factors for the development of atherosclerosis.Excessive plasma trimethylamine-N-oxide（TMAO）,an intestinal metabolite,promotes the development of atherosclerosis,which is a new independent risk factor.Taking effective measures to decrease high cholesterol and triglycerides in serum and reduce plasma TMAO production is considered to be an effective new strategy to prevent atherosclerosis.Probiotics are living microorganisms that are beneficial to humans and animals when administered in adequate amounts,which has the potential to regulate lipid metabolism and reduce TMAO in plasma.In this study,models of hypercholesterolemia and plasma TMAO were used to screen functional probiotic strains that could alleviate hypercholesterolemia and reduce TMAO in plasma.In this study,probiotics were administered to mice to explore the remission of atherosclerotic plaques in mice,and the remission mechanism was explored using 16S r DNA and non-target metabolomics methods.The main findings are as follows:1.Lactobacillus reuteri CCFM8631 treatment was shown to decrease plasma total cholesterol（TC）,low-density lipoprotein-cholesterol,aspartate transaminase,alanine transaminase and trimethylamine N-oxide concentrations,decrease liver TC and malondialdehyde concentrations and recover liver superoxide dismutase concentrations in mice fed a Paigen atherogenic diet.In addition,L.reuteri increased the faecal short-chain fatty acid content（acetate,propionate and butyrate）,which was accompanied by an increase in the relative abundance of faecal Deferribacteres,Lachnospiraceae NK4A136 group,Lactobacillus and Dubosiella;a decrease in the relative abundance of Erysipelatoclostridium and Romboutsia and the activation of butanoate and vitamin B6 metabolism,leading to the alleviation of hypercholesterolaemia.2.Lactobacillus reuteri CCFM8631,Bifidobacterium longum BL and Bifidobacterium breve BB could significantly reduce the contents of plasma TMAO and cecal trimethylamine（TMA）.This reduction was not achieved by affecting the expression of hepatic flavin-containing monooxygenase 3（FMO3）and farnesoid X receptor（FXR）proteins,but is related to the regulation of gut microbiota by lactic acid bacteria.3.TMAO in plasma reached the highest level 4 h after choline intake.One strain of Bifidobacterium breve,two strains of Bifidobacterium longum and eight strains of Lactobacillus reuteri significantly reduced plasma TMAO and plasma and cecal TMA concentrations.This reduction was not achieved by affecting the expression of hepatic FMO3and FXR proteins and TMAO fractional excretion.This may be related to the ability of probiotics to reduce the activity of a choline-trimethylamine lyase-related protein（a glycyl radical enzyme and a glycyl radical activating protein）in the cecum.Moreover,gut microbiota in mice was affected by probiotics.4.Ingestion of Lactobacillus reuteri CCFM1135 and CCFM1040 significantly reduce the plaque area in the aorta and aortic sinus in mice,while reducing the levels of TMAO in plasma and TMA in cecum.These two strains of probiotics could alleviate lipid disorders,reduce serum C-reactive protein and serum glucose concentrations,reduce serum ox-LDL and inflammatory factor levels,and increase cecal acetate and butyrate levels.Inflammatory responses in the aorta and liver of mice were inhibited by reducing the levels of key proteins in the TLR4/My D88/NF-κB/NLRP3 pathway5.Plasma,urine,and cecal content samples of apoE-/-mice were analyzed by untargeted metabolomics.The intake of Lactobacillus reuteri CCFM1135 and CCFM1040 has significant effects on the biological pathways of lipid metabolism（such as primary bile acid biosynthesis）,carbohydrate metabolism（such as propanoate metabolism,butanoate metabolism）,amino acid metabolism,nucleotide metabolism,translation,metabolism of cofactors and vitamins（such as vitamin B6 metabolism）and biosynthesis of other secondary metabolites in mice.Functional simulation of mouse cecal microbiota by picrust2 shows that butanoate metabolism and primary bile acid biosynthesis are greatly affected.Supplementation of Lactobacillus reuteri CCFM1135 and CCFM1040 significantly promoted primary bile acid biosynthesis in the cecal flora. |
