Diagnosis Of Non-alcoholic Fatty Liver Disease And Clinical Studies Of Resistant Starch Intervention

Objectives: Due to the worldwide epidemics of nonalcoholic fatty liver disease(NAFLD),we aimed to evaluate the diagnostic value of combining ultrasonography with biomarkers in identifying NAFLD.We also aimed to investigate whether resistant starch(RS)could improve NAFLD and sought to delineate the possible mechanisms.Methods: 1.The levels of five serum potential biomarkers,fibroblast growth factor 21(FGF21),cytokeratin 18(CK18)M65ED,proteinase 3,neutrophil elastase and alpha1-antitrypsin were measured by enzyme-linked immune-absorbent assay in 422 adult subjects.2.200 NAFLD subjects were randomized to consume 40 g/d of RS or an isocaloric control starch(CS)for 4 months in a randomized,placebo-controlled and double-blinded trial.Anthropometric,biochemical measurements were conducted.Intrahepatic triglycerides content(IHTC)and abdominal fat area were measured by magnetic resonance spectrum(MRS)and magnetic resonance imaging.Glycemic indices and insulin sensitivity were measured by standardized meal tolerance test.3.The alteration of gut microbiota was studied by metagenomic analyses.Fecal and serum metabolites were measured by targeted metabolomics.Results: 1.Among these biomarkers,serum FGF21 was the only biomarker that was independently associated with IHTC(standardized ? = 0.185,p < 0.001),and was found to be an independent risk factor for NAFLD.We established the Mild NAFLD Model derived from FGF21,alanine aminotransferase,triglycerides and body mass index(BMI).The area under the receiver-operating characteristic curve of Mild NAFLD Model was 0.853.Furthermore,a two-step approach combining ultrasonography with the Mild NAFLD Model displayed a better sensitivity for diagnosing mild NAFLD compared with Mild NAFLD Model alone,with a sensitivity of 97.32%and a negative predictive value of 85.48%.2.Compared with baseline values,after 4 months of control starch intervention,IHTC decreased significantly with a change of-2.36%.After 4 months of RS intervention,compared with the CS group,RS significantly lowered IHTC with a mean reduction of-8.98% after adjusting for baseline IHTC values.RS also reduced bodyweight,body fat,abdominal fat,liver enzymes,lipid profiles,fasting insulin,insulin resistance and serum FGF21.3.RS intervention significantly reduced the abundance of 8 species and increased the abundance of3 species of the microbiota.RS also lowered the carbohydrate-digestive capacity of the gut microbiota in the host.Meanwhile,fecal total bile acids,conjugated bile acid and serum components significantly decreased.In addition,RS decreased the serum levels of branched-chain amino acid,aromatic amino acid,glutamic acid and GSG index.Conclusions: 1.The 2-step approach of combining ultrasonography and the Mild NAFLD Model could further improve the sensitivity in diagnosing mild NAFLD confirmed by MRS.2.RS intervention can reduce IHTC,weight,BMI,waist circumference,body fat,abdominal fat,improve liver enzymes,serum lipid profiles,glucose metabolism,and reduce serum FGF21 levels in NAFLD subjects.3.In addition,RS intervention resulted in specific changes of abundance of the gut microbiota,lowered the carbohydrate-digestive capacity of the gut microbiota,and reduced the serum and fecal metabolites.