Quantitative study of digestive enzyme secretion and gastrointestinal lipolysis in chronic pancreatitis

Background & Aims: The contribution of human gastric lipase (HGL) to the overall lipolysis process in chronic pancreatitis (CP), as well as the relative pancreatic enzyme levels, rarely are addressed. This study was designed to quantify pancreatic and extrapancreatic enzyme output, activity, and stability in CP patients vs. healthy volunteers. Methods: Healthy volunteers (n = 6), mild CP patients (n = 5), and severe (n = 7) CP patients were intubated with gastric and duodenal tubes before the administration of a test meal. HGL, human pancreatic lipase (HPL), chymotrypsin, and amylase concentrations were assessed in gastric and duodenal samples by measuring the respective enzymatic activities. Intragastric and overall lipolysis levels at the angle of Treitz were estimated based on quantitative analysis of lipolysis products. Similar analyses were performed on duodenal contents incubated ex vivo for studying enzyme stability and evolution of lipolysis. Results: Although HPL, chymotrypsin, and amylase outputs all were extremely low, HGL outputs in patients with severe CP (46.8 ± 31.0 mg) were 3-4-fold higher than in healthy controls (13.3 ± 13.8 mg). Intragastric lipolysis did not increase, however, in patients with severe CP, probably because of the rapid decrease in the pH level of the gastric contents caused by a higher gastric acid secretion. HGL remains active and highly stable in the acidic duodenal contents of CP patients, and, overall, can achieve a significant lipolysis of the dietary triglycerides (30% of the control values) in the absence of HPL. Conclusions: Although all pancreatic enzyme secretions are simultaneously reduced in severe CP, gastric lipase can compensate partly for the loss of pancreatic lipase but not normalize overall lipolytic activity.