Metabolic Effects of Endogenous Bile Acids After Gastric Bypass Surgery

The study design consists of 4 study visits, two performed before (V1 at day -7 and V2 at day 0 relative to initiation colesevelam treatment) and two after approximately 8 weeks of colesevelam treatment (V3 at day 49 and V4 at day 56). Biometrics, fasting blood samples and a standard mixed meal test are performed at V2 and V4. 75Se-HCAT scintigraphy is carried out between V1 to V2 and V3 to V4, respectively. Between V2 and V3 the subjects will have two telephone calls and one visit at the Endocrine Research Unit for fasting blood samples to make sure they do not experience any adverse events and are compliant.

The control groups will only participate in V1 and V2. The aim with the control groups is to have baseline values for unoperated subjects with and without diabetes to compare with the values in the intervention group after 8 weeks of depletion of endogenous bile acids.

Inclusion criteria

Intervention group

• RYGB-operated ≥ 18 months prior to inclusion
• History of diabetes prior to RYGB (HbA1c ≥48 mmol/mol or use of antidiabetic medication)
• HbA1c <58 mmol/mol on no antidiabetic medication or metformin alone
• Weight change < ±3 kg for >3 months at time of inclusion

Control group A

• No history of diabetes
• HbA1c <48 mmol/mol at time of inclusion
• Fasting plasma glucose < 7.0 mmol/L at time of inclusion
• Weight change < ±3 kg for >3 months at time of inclusion Control group B
• Type 2 diabetes (HbA1c ≥48 mmol/mol or use of antidiabetic medication at time of inclusion)
• Weight change < ±3 kg for >3 months at time of inclusion

Exclusion criteria

• Pregnancy or breastfeeding
• Haemoglobin < 6.5 mmol/L at time of inclusion
• Fasting plasma glucose > 10.0 mmol/L at time of inclusion
• Prior cholecystectomy
• Chronic or tendency to diarrhoea