Liver fat accumulation measured by high-speed T2-corrected multiecho magnetic resonance spectroscopy can predict risk of cholelithiasis

BACKGROUND Liver fat accumulation is associated with increased cholesterol synthesis and hypersecretion of biliary cholesterol,which may be related to the development of cholelithiasis.AIM To investigate whether liver fat accumulation measured by high-speed T2-corrected multi-echo magnetic resonance spectroscopy(MRS)is a risk factor for cholelithiasis.METHODS Forty patients with cholelithiasis and thirty-one healthy controls were retrospectively enrolled.The participants underwent high-speed T2-corrected multi-echo single-voxel MRS of the liver at a 3T MR scanner.The proton density fat fraction(PDFF)and R2 value were calculated.Serum parameters and waist circumference(WC)were recorded.Spearman’s correlation analysis was used to analyze the relationship between PDFF,R2,and WC values.Multivariate logistic regression analysis was carried out to determine the significant predictors of the risk of cholelithiasis.Receiver operating characteristic curve(ROC)analysis was used to evaluate the discriminative performance of significant predictors.RESULTS Patients with cholelithiasis had higher PDFF,R2,and WC values compared with healthy controls(5.8%±4.2%vs 3.3%±2.4%,P=0.001;50.4±24.8/s vs 38.3±8.8/s,P=0.034;85.3±9.0 cm vs 81.0±6.9 cm,P=0.030;respectively).Liver iron concentration extrapolated from R2 values was significantly higher in the cholelithiasis group(2.21±2.17 mg/g dry tissue vs 1.22±0.49 mg/g dry tissue,P=0.034)than in the healthy group.PDFF was positively correlated with WC(r=0.502,P<0.001)and R2(r=0.425,P<0.001).Multivariate logistic regression analysis showed that only PDFF was an independent risk factor for cholelithiasis(odds ratio=1.79,95%CI:1.22-2.62,P=0.003).ROC analysis showed that the area under the curve of PDFF was 0.723 for discriminating cholelithiasis from healthy controls,with a sensitivity of 55.0%and specificity of 83.9%when the cut-off value of PDFF was 4.4%.CONCLUSION PDFF derived from high speed T2-corrected multi-echo MRS can predict the risk of cholelithiasis.

Duodenal-jejunal bypass reduces serum ceramides via inhibiting intestinal bile acid-farnesoid X receptor pathway

BACKGROUND Bile acids play an important role in the amelioration of type 2 diabetes following duodenal-jejunal bypass(DJB).Serum bile acids are elevated postoperatively.However,the clinical relevance is not known.Bile acids in the peripheral circulation reflect the amount of bile acids in the gut.Therefore,a further investigation of luminal bile acids following DJB is of great significance.AIM To investigate changes of luminal bile acids following DJB.METHODS Salicylhydroxamic acid(SHAM),DJB,and DJB with oral chenodeoxycholic acid(CDCA)supplementation were performed in a high-fat-diet/streptozotocininduced diabetic rat model.Body weight,energy intake,oral glucose tolerance test,luminal bile acids,serum ceramides and intestinal ceramide synthesis were analyzed at week 12 postoperatively.RESULTS Compared to SHAM,DJB achieved rapid and durable improvement in glucose tolerance and led to increased total luminal bile acid concentrations with preferentially increased proportion of farnesoid X receptor(FXR)-inhibitory bile acids within the common limb.Intestinal ceramide synthesis was repressed with decreased serum ceramides,and this phenomenon could be partially antagonized by luminal supplementation of FXR activating bile acid CDCA.CONCLUSION DJB significantly changes luminal bile acid composition with increased proportion FXR-inhibitory bile acids and reduces serum ceramide levels.There observations suggest a novel mechanism of bile acids in metabolic regulation after DJB.