Urine bile acids relate to glucose control in patients with type 2 diabetes mellitus and a body mass index below 30 kg/m2.

Bile acids are important endocrine signalling molecules, modulating glucose homeostasis through activation of cell surface and nuclear receptors. Bile acid metabolism is altered in type 2 diabetes mellitus; however, whether this is of pathogenic consequence is not fully established. In this study urinary bile acid excretion in individuals with type 2 diabetes and matched healthy volunteers was assessed. Urinary bile acid excretion in type 2 diabetes patients was considered in the context of prevailing glycaemia and the patient body mass index. Urine bile acids were measured by liquid chromatography-tandem mass spectrometry, allowing individual quantification of 15 bile acid species. Urinary bile acid excretion in patients with type 2 diabetes who were normal weight (BMI 18.5-24.9 kg/m2) and overweight (BMI 25-29.9 kg/m2) were elevated compared to healthy normal weight volunteers, both p<0.0001. In obese (BMI ≥ 30 kg/m2) type 2 diabetes patients, urinary bile acid excretion was significantly lower than in the normal and overweight type 2 diabetes groups (both p<0.01). Total bile acid excretion positively correlated with HbA1c in normal (rs=0.85, p=<0.001) and overweight (rs=0.61, p=0.02) but not obese type 2 diabetes patients (rs=-0.08, p=0.73). The glycaemia-associated increases in urine bile acid excretion in normal weight and overweight type 2 diabetes seen in this study may represent compensatory increases in bile acid signalling to maintain glucose homeostasis. As such alterations appear blunted by obesity; further investigation of weight-dependent effects of bile acid signalling on type 2 diabetes pathogenesis is warranted.

Unconjugated, glycine-conjugated, taurine-conjugated bile acid nonsulfates and sulfates in urine of young infants with cholestasis.

A direct assay system for conjugated bile acids using an enzymatic procedure and high-performance liquid chromatography was used for the analysis of urinary bile acid profiles in young infants with intrahepatic cholestasis (idiopathic neonatal hepatitis syndrome) or extra-hepatic biliary atresia. The major urinary bile acids were cholate and chenodeoxycholate conjugates, but a small amount of deoxycholate and 3 beta-hydroxy-5-cholenate conjugates were detected. Although there was no significant difference in total bile acid excretion between patients with intrahepatic cholestasis and extrahepatic biliary atresia, mean ratios of cholate to chenodeoxycholate and sulfated to total urinary bile acids were different between the two groups examined (5.63 +/- 2.83 vs. 2.50 +/- 1.25, p less than 0.05, 15.8 +/- 9.9 vs. 34.5 +/- 9.9%, p less than 0.005). The proportion of taurine-conjugated chenodeoxycholate in the sulfate fraction to the total bile acid was lower in intrahepatic cholestasis, compared with that in biliary atresia (7.7 +/- 7.5 vs 22.7% +/- 7.8%, p less than 0.005). The greater ratio of cholate to chenodeoxycholate and the reduced excretion of sulfated urinary bile acids in intrahepatic cholestasis was due to decreased taurine-conjugated chenodeoxycholate sulfate excretion.