Changes in Bile Acid Homeostasis and Stool Habits After Cholecystectomy
Phase: PHASE4
Conditions: Bile Acid Malabsorption, Cholelithiasis
Sponsor: Zealand University Hospital

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Changes in bile acid homeostasis and stool habits after 
cholecystectomy 
BACH 
 
 
 
 
 
Ethival comittee number : SJ-434 
EudraCT number: 2016-004692-53 
 
 
ClinicalTrials.gov:  
NCT03168555 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sponsor-investigator 
 
Lars Kristian Munck 
 
Senior Physician, DMSci 
 
Zealand University Hospital, Køge 
Department of Internal Medicine 
Lykkebækvej 1, 4600 Køge 
 
47 32 24 00 (secretary/office) 
 
 
 

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Locations 
Department of Internal medicine 
Sjællands Universitetshospital, Køge  
 
 
Medicinsk Afdeling 
 
 
 
Lykkebækvej 1, 4600 Køge, Danmark. 
 
Department of abdominal surgery 
Sjællands Universitetshospital, Køge  
Medicinsk Afdeling 
Lykkebækvej 1, 4600 Køge, Danmark. 
 
Coolaborators 
Department of Clinical Biochemistry 
Sjællands Universitetshospital, Køge  
Lykkebækvej 1, 4600 Køge, Danmark. 
 
Departement de Chimie  
Sorbonne Universités,  
UPMC Univ Paris 06, Paris, France INSERM-ERL 1157,  
CHU Saint-Antoine 27, Paris, Frankrig 
 
The hospital Pharmacy for Region Zealand 
Afdeling for Klinisk Farmakologi 
Ringstedgade 65,  
4700 Næstved, Danmark. 
 
Monitorering 
The GCP Unit at Copenhagen University hospitals 
Bispebjerg Hospital, Bygning 51, 3.sal  
Bispebjerg Bakke 23  
2400 København NV, Danmark 
 
 
Abbreviations 
BAD: galdesyrediarré (Bile Acid Diarrhoea), C4: 7α-hydroxy-4-cholesten-3-on, CDCA: chenodeoxycholsyre, 
ELISA: enzyme linked immunosorbent assay, GIQLI: gastrointestinal quality of life index, HPLC: high 
performance liquid chromatography, LC-MS/MS: liquid chromatography tandem mass spectrometry, 
SeHCAT: 75Selenium konjugeret til taurin-homocholsyre, FGF19: fibroblast vækstfaktor 19. 
 
 

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Aim 
To explore the effect of cholecystectomy on the biomarkers of bile acid diarrhea fibroblast vækstfaktor 19 
(FGF19) 
and 
7α-hydroxy-4-cholesten-3-one 
(C4) 
during 
fasting 
and 
after 
stimulation 
with 
chenodeoxycholsyre (CDCA). Secondarily the effect on changes in stool pattern in general and correlated to 
changes in biomarkers are explored. 
 
Background 
Bile acid diarrhoea (BAD) is a common cause of chronic watery diarrhea that impairs quality of life (1). BAD 
is classified into three types - type 1: secondary to disease of the terminal ileum incl. resection or radiation-
damaged terminal ileum. Type 2: primary or idiopathic and type 3: secondary to other disease such as 
microscopic colitis or cholecystectomy (2). The prevalence of BAD is up to 30% among unselected patients 
with chronic watery diarrhea (3), ca. 40% of patients with microscopic colitis (4) and 20-30% of patients with 
irritable bowel syndrome with diarrhea (5-7) and BAD contribute to diarrhea in Crohn's disease with terminal 
ileitis and after small bowel resection (8). BAD occurs with a higher prevalence after cholecystectomy (9). 
Overall, the prevalence of BAD is estimated at 1% of the population (10).  Clarification of whether a patient 
has BAD is therefore important in the investigation of chronic watery diarrhea, as there is medical treatment 
of BAD (3, 6, 11, 12). The current study to diagnose BAD is called SeHCAT named after the isotope 75Selenium 
conjugated with tauro-homocholic acid called 75Se-HCAT (13). After seven days, the retention is measured 
and the fraction between γ-radiation on day 7 and day 0 is the test result. There are arbitrarily set limits of 
retention <5% severe, <10% moderate, and <15% mild BAD. There is often a long wait for SeHCAT and doctors 
often refer late for the examination, so patients wait a long time before being diagnosed. 
 
New biomarkers of bile acid diarrhoea 
In recent years, greater physiological knowledge has emerged about the circulation and regulation of bile 
acids at a molecular level. (14) and the regulation of bile acid synthesis (15). This has led to the identification 
of possible biochemical markers for BAD that correlate with SeHCAT retention and inventories further show 
a close inverse correlation between high values of 7α-hydroxy-4-cholesten-3-one (C4) and low SeHCAT 
retention (16).  
The hormone FGF19 is released primarily by enterocytes in the terminal ileum in response to bile acid 
absorption from active absorption in the terminal ileum and exerts negative feedback on the bile acid 
synthesis in the liver. The concentration of FGF19 increases postprandially and reaches a maximum after 100-
120 minutter (17). FGF19 increases with oral administration of bile salts and decreases with administration 
of cholestyramine (18). The bile acid chenodeoxycholic acid (CDCA) is a potent agonist of FXR and thus 
transcription of FGF19 (19). C4 is an intermediate product in bile acid synthesis and is a marker for new 
formation of bile acid. Walters et al. (2, 20) has hypothesized that defective FGF19 synthesis or signaling is 
the mechanism behind idiopathic BAD and has shown that fasting FGF19 correlates inversely to C4 (16) and 
subsequently, that low fixed values of FGF19 correlate to BAD measured by SeHCAT (21). Measurements of 
C4 are made experimentally in the diagnosis of BAD in countries where SeHCAT is not available, primarily the 
USA, but the measurement requires analysis of high-performance liquid chromatography (HPLC) and 
therefore has low availability (3). Therefore, the hope has been that FGF19 either alone or together with C4 
could replace SeHCAT. However, variance in FGF19 values and overlap between patients with BAD and 

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healthy means that a single fasting sample does not have sufficient diagnostic power to make the diagnosis. 
(21). We have found that the postprandial increase in FGF19 is smaller in patients with BAD than in healthy 
people in a single measurement 60 minutes after a meal. (22). Furthermore, in a prospective, exploratory 
pilot study, we have confirmed this and mapped the temporal hormonal response after stimulation with food 
and the bile acid chenodeoxycholic acid (CDCA) (23). 
 
Bile acid diarrhoea after cholecystektomy 
 
The prevalence of chronic diarrhea after cholecystectomy is estimated at 5-10% (2), but this is not well 
examined. However, diarrhea complaints after cholecystectomy are frequently seen in gastroenterological 
outpatient clinics and many of these patients have bile acid diarrhea (2). FGF19 is formed in addition to the 
intestine also in the endothelium of the gallbladder and excreted via the bile in high concentrations to the 
intestine, but the effect of this is unknown (18). In a prospective study of 106 patients referred for elective 
cholecystectomy, stool pattern was compared with 37 women referred for laparoscopic sterilization. The 
cholecystectomized women reported less sensation of constipation and marginally more frequent 
defecation, but no actual change in bowel movements. (2). Cholecystectomy thus presumably triggers 
increased fluid in the stool in the colon, which in most cases is reabsorbed and therefore does not clinically 
lead to diarrhea. In another prospective study of 51 patients before and after cholecystectomy, patients 
reported having more and thinner stools and found increased production of bile acids detected by C4 (24). 
 
Recently, Barrera et al examined 8 patients who had cholecystectomy due to gallstones and 8 patients 
who had their gallbladder removed for another reason. (25). Before and after cholecystectomy, fasting blood 
samples were taken at 08:00h and after a breakfast serial blood tests. FGF19 was maximal at 12:00 before 
cholecystectomy 250 pg/mL, and after cholecystectomy only 150 pg/mL. Cholecystectomy doubled fasting 
C4 and the association between C4 and FGF19 (16) disappeared after cholecystectomy. No stool pattern was 
measured. 
 
 

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Problem statement 
The significance of the gallbladder in the hormonal balance of bile acids is unclear. Our blood test for BAD is 
based on changes in FGF19 from fasting to 90 – 150 minutes after stimulation with food and CDCA. The 
present study aims to elucidate the effect of cholecystectomy on bile acid homeostasis and on the feedback 
mechanisms. A study of how cholecystectomy affects FGF19 is further important to investigate the 
association between stool changes and FGF19 after cholecystectomy. The primary purpose of the study is to 
describe the effect of cholecystectomy on fasting as well as meal plus CDCA stimulated FGF19 and C4 during 
the time period relevant to our test. 
 
Design 
Prospective, non-randomized, open label.  20 patients are examined before and after cholecystectomy.  
Inclusion criteria 
Patients referred for elective cholecystectomy 
 
≥ 18 years old  
 
≤ 80 years old 
Exclusion criteria 
 
Small bowel resection  
 
Right sided hemocolectomy  
 
Know diarrheal disease  
o Celiac disease  
o Lactose intollerancy 
o Inflammatory bowel disease, incl. Microscopic colitis  
 
Pregnancy  
 
Allergy to eggs 
 
Contraindications to Xenbilox: 
o allergy to constituenmts in the xenbilox capsules 
o medical contraindications:  
 
chronic or acute cholecytitis within two months.  
 
Cirrosis  
 
Suspected obstructive choledocholithiasis.  
 
Icterus 
 
Plasma bilirubin > 1.5 times upper normal limit  
Withdrawal criteria 
Operative complications during or after the cholecystectomy 
 
Lesion of ductus choledochus  
 
 

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Methods 
The below procedures are done before cholecystectomy and scheduled 3–5 months postoperative. Bowel 
habits are registered for seven days ahead of each study visit. The Bristol type of each stool is registered. 
Study visits 1 and 2 – ie. before and after cholecystectomy: the patient meets in the after an overnight fast. 
A catheter is placed in the cubital vein and a fasting blood sample is collected. This sample must be taken 
before 10:00 AM. The patient takes 1,250mg chenodeoxycholic acid (CDCA) (5 Xenbilox capsules of 250mg) 
and ingests the study meal within 15 minutes. The meal consists of 2 slices of toast, two boiled eggs and 500 
mL water. 
 
Blood samples are taken trhough the catheter at 60, 90, 120 og 150 minutes after ingestion of  CDCA) 
 
Questionaires 
At visit 1 and visit 2 the following quistionnaires are completed  
1. Abdominal symptoms 
2. Short Health Scale  
3. gastrointestinal quality of life index (GIQLI). 
 
Laboratory analyses 
FGF19 is analyzed with a commercial ELISA researchkit (R&D systems, MN, USA). Bile acids including C4 and 
CDCA are analyzed with liquid chromatography tandem mass spectrometry (LC-MS/MS). 
 
Statistics 
Stimulated FGF19 peak values at 150 minutes were estimated to 350 pg/mL (25, 29) and after 
cholecystectomy to 250–300 pg/mL (20), both with a standard deviation of 100. We expected no significant 
change in fasting FGF19 relative to the peak levels. With two-sided α = 0.05 and β = 0.20 we needed 10–34 
patients with paired measurements. We decided on 16 patients to detect a 75 pg/mL change in Δ0-150FGF19 
with 80% power. 
Results are described with means or medians according to distribution. Results are paired and are analysed 
with either paired t-tests or Wilcoxon test (IBM SPSS 24 Inc., Chicago, IL, USA.) 
 
 
Primary endpoint: 
 
Change in CDCA stimulated FGF19 (Δ 150 – 0 min) after cholecystektomy 
 
Secondary endpoints: 
 
Change in CDCA absorption to plasma (AUC) after cholecystektomy 
 
Change in fasting and stimulated C4 after cholecystektomy 

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 
Change in fasting FGF19 after cholecystektomy. 
 
Change in stool pattern after cholecystektomy. 
o Mean stools per day (frequency) 
o Mean Bristol stool type per stool (consistency) 
 
Change in stool frequency correlated to changes in 
o Fasting FGF19  
o Fasting C4 
 
Change in plasma triglycerides after cholecystectomy 
 
Change in patient reported diarrhea correlated to changes in 
o Fasting FGF19 
o Fasting C4 
 
 
 

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