Cephalic phase of lipolysis is impaired in pancreatic insufficiency: role of gastric lipase.

BACKGROUND

Gastric lipase contributes significantly to overall lipolysis and is regulated by interacting neuro-hormonal mechanisms. Patients with alcoholic chronic pancreatitis (ACP) have low, or even absent, activity of pancreatic lipases. In that state the secretion of gastric lipase could be essential and compensate for the pancreatic defect. However, conflicting studies have not resolved the order of magnitude of gastric lipase secretion in these patients. This could be explained by differences in regulatory mechanisms, gastric mucosal changes, and abdominal vagal tone.

METHODS

Nasogastric intubation with modified sham feeding and upper endoscopy including biopsies for histologic classification and Helicobacter pylori infection status were performed in eight ACP patients, and eight healthy volunteers were studied on separate occasions. Vagal nerve function was assessed by calculation of heart rate variability in ACP patients. Gastric lipase was measured in aspirates by means of enzyme-linked immunosorbent assay and an enzyme kinetic assay. Plasma concentrations of gastrin, secretin, cholecystokinin, and pancreatic polypeptide were measured throughout the study.

RESULTS

Sham feeding rapidly and significantly increased gastric lipase secretion in healthy volunteers, whereas ACP patients did not respond to sham feeding. Two of eight patients were infected with H. pylori and had mucosal changes accordingly. The lack of lipase response could not be ascribed to dysfunction of the abdominal vagus.

CONCLUSIONS

The cephalic phase of gastric lipase secretion is impaired in ACP patients. Although their fundic cells continue to secrete gastric lipase, they are not subject to normal neuro-hormonal regulation.