Page 91 - Human Bile Acid Metabolism: a Postprandial Perspective

Short term starvation and bile acid supplementation
Statistical Analysis
Concentrations and area under the curves (AUCs) are presented as median and
interquartile range (IQR) unless otherwise stated. For visual purposes, data in
graphs are displayed as means ± SE. AUCs and incremental AUCs (iAUCs), by
using baseline subtracted values, were calculated with the trapezoidal rule. The
total bile acid (TBA) concentration is the sum of the unconjugated and conjugated
forms of CA, CDCA, DCA, and UDCA. The lithocholic acid (LCA) concentrations
were all below the detection limit and therefore not included in the data analysis. A
P value below 0.05 is considered as statistically significant. Comparisons between
two conditions were evaluated with either paired t-testing for normally distributed
data or the Wilcoxon signed rank test for nonparametric distribution. We used a
two-way repeated measurement ANOVA (2-way RM-ANOVA) for the analyses
of differences in postprandial curves between the mixed meal tests, including
fasted concentrations (t = 0). When the two-way RM-ANOVA was statistically 5 significant, we performed post hoc Bonferroni testing to detect the specific
differences in the individual time points. Correlations between individual BA species, insulin, GLP-1, and FGF19 were tested on all time points using Pearson’s correlation for normally distributed data or Spearman’s Rho for nonparametric data. The Bonferroni test was used to correct for multiple testing and only highly significant results are reported. Statistical analysis was performed using IBM SPSS Statistics 24 (IBM, Armonk, NY) and GraphPad Prism 7.02 (GraphPad Software Inc., La Jolla, CA). Graphs were made using GraphPad Prism 7.02.
Results
Subject Characteristics
We included 9 healthy, lean men (median [IQR] age 23.1 [2.8] years, 79.0 [14.0] kg, height 187.0 [9.5] cm, BMI 23.1 [2.8] kg/m2) for the experiment 1 and 10 healthy lean men (age 24.5 [5.0] years, 74.4 [10.2] kg, height 183.0 [7.8] cm, BMI 22.1 [2.6] kg/m2) for experiment 2. In both experiments, all subjects completed the study procedures.
Experiment 1
Plasma glucose and insulin concentrations after 40 h of fasting. Forty hours of fasting lowered premeal plasma glucose concentrations (baseline 14 h FAST: 5.3
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