Abstract
IntroductionDelayed gastric emptying and feed intolerance occur frequently in the critically ill. In these patients, gastric motor responses to nutrients are disturbed. Peptide YY (PYY) slows gastric emptying. The aim of this study was to determine fasting and nutrient-stimulated plasma PYY concentrations and their relationship to cholecystokinin (CCK) in critically ill patients.MethodsStudies were performed in 19 unselected mechanically ventilated critically ill patients (12 males; 48 ± 7 years old) in a randomised, single-blind fashion. Subjects received a 60-minute duodenal infusion of Ensure® at either 1 or 2 kcal/minute. Blood samples were collected at baseline and at 20, 40, 60, and 180 minutes following commencement of the nutrient infusion for the measurement of plasma PYY and CCK concentrations (using radioimmunoassay). Patient data were compared to 24 healthy subjects (17 males; 43 ± 2 years old).ResultsFasting PYY concentration was higher in patients (P < 0.05), particularly in those with feed intolerance (P < 0.05). Plasma PYY concentrations were higher in patients during nutrient infusion (area under the curve [AUC] at 1 kcal/minute: 2,265 ± 718 versus 1,125 ± 138 pmol/l.min, P < 0.05; at 2 kcal/minute: 2,276 ± 303 versus 1,378 ± 210 pmol/l.min, P = 0.01) compared to healthy subjects. The magnitude of PYY elevation was greater in patients during the 1 kcal/minute infusion (AUC: 441 ± 153 versus 186 ± 58 pmol/l.min, P < 0.05), but not the 2 kcal/minute infusion. Fasting and nutrient-stimulated plasma CCK concentrations were higher in patients (P < 0.05). There was a relationship between plasma PYY and CCK concentrations during fasting (r = 0.52, P < 0.05) and nutrient infusion (r = 0.98, P < 0.0001).ConclusionIn critical illness, both fasting and nutrient-stimulated plasma PYY concentrations are elevated, particularly in patients with feed intolerance, in conjunction with increased CCK concentrations.
Highlights
Delayed gastric emptying and feed intolerance occur frequently in the critically ill
It was shown that in critical illness, (a) plasma Peptide YY (PYY) concentrations are elevated during both fasting and nutrient stimulation, in patients who are intolerant to gastric feeding, (b) the release of PYY in response to nutrients does not exhibit the same dose dependency as evidenced in health, and (c) there is a close relationship between nutrient-stimulated plasma PYY and CCK concentrations
The role and specificity of these hormones in feed intolerance can be evaluated further by assessing other gut hormones, such as glucagon-like-peptide 1, secretin, gastric inhibitory polypeptide, neurotensin, and motilin. Both fasting and duodenal nutrient-stimulated plasma PYY concentrations are elevated in critical illness, in patients who are intolerant to gastric feeding
Summary
Delayed gastric emptying and feed intolerance occur frequently in the critically ill In these patients, gastric motor responses to nutrients are disturbed. Peptide YY (PYY) is an important humoral mediator of the entero-gastric feedback mechanism, which leads to a slowing of gastric emptying and small intestinal transit [4,5,6] and possibly to a suppression of energy intake [1,7,8]. Exogenous administration of PYY slows gastric emptying [3,10], which is associated with an inhibition of antral motility [10] This may contribute to a reduction in energy intake and APACHE = acute physiology and chronic health evaluation; AUC = area under the curve; BMI = body mass index; CCK = cholecystokinin; CV = coefficient of variation; ICU = intensive care unit; NG = naso-gastric; PYY = peptide YY; TMPD = trans-mucosal potential difference
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