Conditions: Postprandial Hypoglycemia
Keywords: Post prandial hypoglycemia hypoglycemia Nissen fundoplication Dumping
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 7
Healthy volunteers: no

Brief summary:
It has been proposed that the rapid gastric emptying of carbohydrate containing fluids into the intestine causes hyperglycemia followed by reactive hypoglycemia. The investigators have shown that glucagon-like peptide-1 (GLP-1) secretion in response to a glucose load is increased in children with Post-prandial hypoglycemia (PPH). This is a proof of concept study to investigate the causative role of GLP-1 in the pathophysiology of PPH after fundoplication by evaluating the effects of GLP-1 receptor antagonism on metabolic variables after a mixed meal.

Hypothesis: In children with post-prandial hypoglycemia after fundoplication, antagonism of the GLP-1 receptor by exendin-(9-39) will elevate nadir blood glucose levels after a meal challenge and prevent post-prandial hypoglycemia.

Detailed description:
PPH is a frequent complication of fundoplication in children. The mechanism responsible for the PPH is poorly understood, but involves an exaggerated insulin response to a meal and subsequent hypoglycemia. We have shown that children with PPH after Nissen fundoplication have abnormally exaggerated secretion of GLP-1, an incretin hormone with multiple glucose lowering effects including stimulation of insulin secretion and suppression of glucagon secretion. In this study we seek to examine the causal role of endogenous GLP-1 in PPH after fundoplication by evaluating the effects of antagonizing the GLP-1 receptor with exendin-(9-39) on key metabolic features of PPH.

Arms:
arm 1: After an overnight fast, an intravenous (IV) infusion of Exendin-(9-39) will be started 1 hour prior to the meal challenge and continued for 5 hours. After the first hour of the infusion, subjects will undergo a mixed meal tolerance test in which Pediasure (10cc/kg) will be consumed by mouth or gastrostomy/nasogastric tube over a period of 15 minutes (for infants under 12 months, Pediasure will be replaced by the infant's formula). Blood samples will be drawn at different time points during the infusion to measure blood glucose, plasma insulin, glucagon and plasma glucagon-like-peptide-1 (GLP-1). The Exendin-(9-39) dose for the first 3 subjects will be 300pmol/kg/min and, if tolerated, the dose will be increased to 500pmol/kg/min for subsequent subjects.

The next day, all procedures will be repeated except subjects will receive an IV infusion of normal saline (vehicle) over 6 hours. arm 2: After an overnight fast, an intravenous (IV) infusion of normal saline (vehicle) will be started 1 hour prior to the meal challenge and continued for 5 hours. After the first hour of the infusion, subjects will undergo a mixed meal tolerance test in which Pediasure (10cc/kg) will be consumed by mouth or gastrostomy/nasogastric tube over a period of 15 minutes (for infants under 12 months, Pediasure will be replaced by the infant's formula). Blood samples will be drawn at different time points during the infusion to measure blood glucose, plasma insulin, glucagon and plasma glucagon-like-peptide-1 (GLP-1).

The next day, all procedures will be repeated except subjects will receive an IV infusion of Exendin-(9-39) which will be started 1 hour prior to the meal challenge and continue for 5 hours. The dose for the first 3 subjects will be 300pmol/kg/min and, if tolerated, the dose will be increased to 500pmol/kg/min for subsequent subjects.

Interventions: intervention 1: Exendin-(9-39) intervention 2: Vehicle
Intervention descriptions: intervention 1: IV infusion of exendin-(9-39) for 5 hours intervention 2: Normal saline (vehicle) infusion for 5 hours at 0.06 mL/kg/hr

Protocol document: