Serum ghrelin and PYY enterohormones during acute critical illness: A prospective observational trial

Introduction Gastrointestinal failure during critical illness is associated with decreased intake and limited tolerance to enteral feeding. Enterohormones like ghrelin and PYY could play a role in these dysfunctions. This study aimed at defining: – the time course of serum ghrelin and PYY during the first 5 days of stay; – correlations with limited tolerance to enteral feeding. Material and methods Thirty consecutive patients (age: 56.4 ± 16.4; BMI: 26.3 ± 4.5) and 10 fasting healthy volunteers (age: 34.1 ± 6.8; BMI: 23.1 ± 4.2) were included. In patients, blood was sampled for 5 consecutive days and once in the control group. Blood samples were immediately centrifuged at 3000 ×  g for 10 minutes at 4 °C. Ghrelin samples were acidified to pH 4 and then all samples were stored at –80 °C until processing. Ghrelin and PYY serum concentrations were measured using a commercial ELISA test. Enteral feeding intolerant patients were defined as patients with at least one episode of high gastric residual volume (u003e 250 mL) and/or diarrhea (u003e 200 mL of liquid stools/day). Comparisons between continuous variables were done using ANOVA and the Wilcoxon U -test as appropriated. Alpha error was set at 5%. Results The incidence of intolerance among patients was 41.4%. Mean gastric residual volume (millilitres) was higher in intolerant than in tolerant patients ( P P  = 0.03) and than controls (53.5 pg/mL [17.5–191.7 pg/mL] vs. 6.4 pg/mL [0.35–18.1 pg/mL]; P  = 0.02). Daily PYY serum concentration was higher in intolerant than in tolerant patients, specifically on days 2 (median (IQR): 103.2 pg/mL [23.2–193.6 pg/mL] vs. 16.9 pg/mL [3.9–54 pg/mL]; P  = 0.02) and day 5 (103.2 pg/mL [23.2–193.6 pg/mL] vs. 16.9 pg/mL [3.9 to 54 pg/mL]; P  = 0.02). Controls had a significantly higher serum ghrelin concentration than either tolerant patients (median (IQR): 1435.7 pg/mL [1335.5–1775.5 pg/mL] vs. 219.4 pg/mL [84–420.5 pg/mL]; P P  = 0.004). Unexpectedly, serum ghrelin concentration was higher in intolerant compared to tolerant patients (median (IQR): 283.5 pg/mL [92–1002.5 pg/mL] vs. 219.4 pg/mL [84–420.5 pg/mL]; P  = 0.02). No difference in serum ghrelin concentration between tolerant compared to intolerant patients was found from day 1 to day 5. Conclusions In critically ill patients, mean serum concentration of ghrelin and PYY significantly differ from that of healthy controls. These findings support a role of enterohormones in the critical illness-associated gastrointestinal failure.