Effect of acute pancreatitis on porcine intestine: a morphological study

The ultrastructural changes in the intestine were studied during experimental acute edematous and necrotizing porcine pancreatitis. The immunohistochemical expression of E-cadherin and β-catenin in the jejunum and colon was assessed to characterize changes in the adherens junctions.

Twenty-four pigs were randomized to controls (n = 8) or to develop mild edematous (n = 8, saline infusion to pancreatic duct) or severe necrotizing pancreatitis (n = 8, taurocholic acid infusion). The ultrastructure of the mesenteric artery and the vein and epithelium of the jejunum and colon was analyzed at baseline and after 540 min with electron microscopy. The expression of E-cadherin and β-catenin was assessed with immunohistochemistry.

In the colon the microvilli and their glycocalyx shortened and reduced in density the most in necrotizing pancreatitis. In necrotizing pancreatitis adherens and tight junctions were occasionally open in the colon but rarely in the jejunum. Mitochondria in the colon epithelial cells were degenerated in necrotizing pancreatitis, swollen in edematous pancreatitis, and remained intact in the control case. In necrotizing pancreatitis, capillaries of the colon showed a broken endothelial lining with narrow lumens. The expression of E-cadherin immunoreactivity showed a trend toward a decrease in the colon in both edematous and necrotizing pancreatitis.

Ultrastructural abnormalities in acute pancreatitis appear early in the colon, where they seem to be more damaging than in jejunum. Epithelial cell damage seems to include mitochondrial injury and an opening of tight and adherens junctions, which are more pronounced in necrotizing pancreatitis. Damage is seen in the mucosal and mesenteric endothelial cells.