Effects of Intraduodenal Nutrient Infusion on CCK Levels, LES Pressure, and Gastroesophageal Reflux (GER)

Abstract

Purpose: Background: Fats are associated with increased GER and CCK (cholecystokinin) is thought to play a role. The contribution of other nutrients to GER is not well described. Aims: Evaluate the effects of intraduodenal nutrient infusion on serum CCK levels, lower esophageal sphincter (LES) pressure, and GER. Methods: 24 healthy asymptomatic Caucasian volunteers were studied. A water-perfused, 6 cm Dent sleeve catheter (Dentsleeve International Ltd) was positioned across the LES fluoroscopically; an infusion port was located in the 2nd portion of the duodenum. An impedance-pH catheter (Sandhill Scientific) was attached to the catheter with the pH probe 5 cm above the upper border of the LES. After a 1-hour accommodation period baseline CCK levels were measured. Volunteers were randomized to receive one of 3 separate 60 kcal nutrient infusions over 30 minutes (2 cc/min): fat (F; Microlipid, Novartis Medical Nutrition); carbohydrate (C; Polycose, Ross Nutrition); or protein (P; Beneprotein, Novartis Medical Nutrition). All substances were dispersed in normal saline. Blood samples were drawn 5, 10, 15, and 25 minutes after nutrient infusion. LES resting pressure was measured at baseline and 60 minutes after nutrient infusion. Reflux events were categorized as either acid or non-acid in nature using a pH cut-off of 4.0. Results: No statistically significant difference was found among the 3 groups with regards to demographics, number of reflux events, number of acid events or percent of time with acid. A trend was noted for increased reflux and acid exposure events in the fat group. CCK levels were significantly higher in the fat group compared to the other 2 groups at 10, 15, and 25 minutes after nutrient infusion. The mean post-infusion LES pressure was significantly lower than mean baseline LES pressure in the F group (P= 0.02). Conclusion: Intraduodenal fat infusion led to a statistically significant increase in CCK levels in normal volunteers, while protein and carbohydrate did not. Reflux events were more frequent in volunteers infused with fat compared to protein or carbohydrate, although this did not reach statistical significance. LES pressure decreased significantly after fat infusion. Further studies are needed to better define the relationship between fat infusion, CCK release, LES pressure, and GER.Table