الملخص
Objective To explore the role of TMAO from gut microbiota in non-alcoholic fatty liver disease(NAFLD),we detected the serum level of TMAO and its precursor metabolites in NAFLD,as well as the expression level of Eubacterium rectum,Bacteroidetes multiforme,Lactobacillus and bifidobacterium in the intestinal flora.Methods We collected 118 subjects and divided into NAFLD group(86 cases)and healthy control group(32 cases)randomly.We also detected the serum level of TMAO and its precursor metabolites in subjects by high performance liquid chromatography tandem mass spectrometry detection(LC-MS),and the expression of target bacterial DNA was detected by qRT-PCR.Results Serum TMAO,TMA and choline levels were significantly increased in NAFLD(P<0.05),and liver fat content was positively correlated with TMAO(P<0.05).The expression level of Lactobacillus and Eubacterium rectum in NAFLD group were increased(P<0.05);the expression level of Bifidobacterium and Bacteroides multiform were decreased(P<0.05).The serum TMAO level was positively correlated with Eubacterium rectum(r=0.280,P<0.05),and negatively correlated with Bifidobacterium(r=-0.332,P<0.05).Conclusion The level of TMAO in serum shows a positive correlation with NAFLD.The structure of intestinal flora in individuals with NAFLD is altered and linked to TMAO.This suggests that the intestinal flora may have a significant impact on the development of NAFLD through TMAO.
الملخص
Trimethylamine-N-oxide (TMAO) has emerged as a potential biomarker for atherosclerosis and the development of cardiovascular diseases (CVDs).Although several clinical studies have shown striking associations of TMAO levels with atherosclerosis and CVDs,TMAO determinations are not clinical routine yet.The current methodology relies on isotope-labeled internal standards,which adds to pre-analytical complexity and costs for the quantification of TMAO and its precursors carnitine,betaine or choline.Here,we report a liquid chromatography-tandem mass spectrometry based method that is fast(throughput up to 240 samples/day),consumes low sample volumes (e.g.,from a finger prick),and does not require isotope-labeled standards.We circumvented the analytical problem posed by the presence of endogenous TMAO and its precursors in human plasma by using an artificial plasma matrix for cali-bration.We cross-validated the results obtained using an artificial matrix with those using mouse plasma matrix and demonstrated that TMAO,carnitine,betaine and choline were accurately quantified in 'real-life'human plasma samples from healthy volunteers,obtained either from a finger prick or from venous puncture.Additionally,we assessed the stability of samples stored at-20 ℃ and room temperature.Whereas all metabolites were stable at-20 ℃,increasing concentrations of choline were determined when stored at room temperature.Our method will facilitate the establishment of TMAO as a routine clinical biomarker in hematology in order to assess the risk for CVDs development,or to monitor disease progression and intervention effects.
الملخص
The intestine microbiota and the host interacts with each other.Resently,the association and causality between gut microbiota and cardiovascular diseases have been well studied.Some underlying mechanisms,especially metabolic pathways are known, including the role of trimethylamine N-oxide in the pathogenesis of atherosclerotic heart disease and heart failure and that of short chain fatty acids and their receptors in blood pressure regulation.