Survival of human pancreatic enzymes during small bowel transit: effect of nutrients, bile acids, and enzymes

Abstract

The activity of pancreatic enzymes declines during aboral intestinal transit. We tested the hypothesis that survival of pancreatic enzyme activities during intestinal transit is affected by amounts or concentrations of calories, nutrients, bile acids, or pancreatic enzymes entering the segments of the small intestine. An oroileal tube was placed in 26 healthy humans. The tube had duodenal, jejunal, and ileal infusion ports for nonabsorbable markers and aspiration ports in the distal duodenum, distal jejunum, and distal ileum. Four infusates of different proportions of protein, fat, and carbohydrate were infused continuously into the duodenum at 40, 90, and 160 kcal/h. Of the nutrients infused into the proximal duodenum, 21 +/- 3, 51 +/- 7, and 39 +/- 5% of fat, protein, and carbohydrate, respectively, were delivered to the distal duodenum. During duodenoileal transit, lipase, chymotrypsin, amylase, and trypsin lost 71 +/- 5, 63 +/- 5, 43 +/- 7, and 38 +/- 9% of activity, respectively (P < 0.01 vs. distal duodenum). During duodenojejunal transit, the activity of each enzyme decreased more than 35% (P < 0.01 vs. distal duodenum), and infusion of more calories into the duodenum improved survival of all enzymes except trypsin (P < 0.05). During jejunoileal transit, greater amounts and concentrations of calories and carbohydrate improved survival of only lipolytic activity (P < 0.01, P < 0.05, respectively), and loss of lipolytic activity correlated directly with delivery of bile acids (r = 0.56, P = 0.05) and chymotrypsin (r = 0.80, P = 0.001) to the distal jejunum. We conclude that intraluminal nutrients increase survival of enzyme activities in the proximal intestine. After absorption of nutrients, the action of chymotrypsin and bile acids decrease lipolytic activity more than activity of other enzymes.

Stimulation of small intestinal burst activity in the postprandial state differentially affects lipid and glucose absorption in healthy adult humans

“…Evidence in humans suggests that the pancreatic response to a meal is regulated by the rate of nutrient delivery (17). In addition, Holtmann et al (12) showed an inverse relationship between small intestinal transit and pancreatic lipase activity. An accelerated transit of the nutrient meal, through the stimulation of small intestinal burst activity, may have blunted the pancreatic response and could explain the diminution of lipid uptake.…”

Roles of molecular chaperones in pancreatic secretion and their involvement in intestinal absorption

“…The mechanism by which CDL activity is destroyed lies on chymotrypsin-catalyzed proteolysis. Less than 1% of the lipolytic activity secreted into the duodenum reaches the ileum as compared to 22% for the trypsin activity (Holtmann et al, 1997). As for CDL, BSDL could be extremely sensitive to proteolysis and easily degraded by chymotrypsin.…”

“…The rates of degradation, however, differ from one enzyme to the other (Holtmann et al, 1997). In what concerns CDL, its activity decreases rapidly in contrast to proteases and amylases, which are relatively more stable.…”

Delayed release pancrelipase for treatment of pancreatic exocrine insufficiency associated with chronic pancreatitis

“…2,3 In addition, in the acidic duodenal milieu, bile salt precipitation and subsequent adsorption to undigested food reduces the bile salt pool. 4,5 And finally, CP patients are believed to have a defect in ileal mucosal absorption of bile salts, effectively reducing the availability of bile salts for enterohepatic circulation.…”