title: Two time-point assessment of bile acid kinetics in humans using stable isotopes.
abstract: The stable isotope dilution measurement of bile acid pool sizes and turnover rates in humans has involved the collection of nine blood samples over four days. This precludes widespread application to larger population studies. This study describes a two time-point approach for blood sampling without loss of statistical power. Isotopic decay curves of cholic acid, chenodeoxycholic acid and deoxycholic acid acquired in three recent human studies were analysed. The optimal combination of two time-points was determined. Time-points around 12 and 72 h after administration allowed for the most accurate description of the decay curves and prediction of kinetic parameters. Analyses of 39 statistical comparisons of kinetic parameters based upon the two time-points and all time-points approaches exhibited only one slightly discrepant result. In conclusion, for group comparison of bile acid kinetics in humans, a two time-point blood collection approach at time-points near 12 and 72 h provides statistically reliable data.
authors.affiliation: Department of Laboratory Medicine, University Medical Center, Groningen, The Netherlands. f.stellaard@med.umcg.nl
authors.forename: Frans
authors.initials: F
authors.lastname: Stellaard
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Bloks
authors.forename: Hans G M
authors.initials: HG
authors.lastname: Burgerhof
authors.forename: Richard A
authors.initials: RA
authors.lastname: Scheltema
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Murphy
authors.forename: Hans A
authors.initials: HA
authors.lastname: Romijn
authors.forename: Guus H M
authors.initials: GH
authors.lastname: Smelt
authors.forename: Gemma
authors.initials: G
authors.lastname: Brufau
authors.forename: Folkert
authors.initials: F
authors.lastname: Kuipers
mesh_terms: D001647:Bile Acids and Salts / Q000097:blood*; D002247:Carbon Isotopes / Q000032:analysis*; D002635:Chenodeoxycholic Acid / Q000097:blood; D019826:Cholic Acid / Q000097:blood; D003840:Deoxycholic Acid / Q000097:blood; D003903:Deuterium / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005260:Female; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood; D007553:Isotope Labeling / Q000379:methods; D007700:Kinetics; D008297:Male; D009765:Obesity / Q000097:blood; D011865:Radioisotope Dilution Technique; D012016:Reference Values; D013997:Time Factors
chemical_list: D001647:Bile Acids and Salts; D002247:Carbon Isotopes; D003840:Deoxycholic Acid; D002635:Chenodeoxycholic Acid; D003903:Deuterium; D019826:Cholic Acid