Circulating concentrations of porcine ileal peptide but not hexosaminidase are elevated following 1 hr of mesenteric ischemia

Abstract

Porcine Ileal Peptide (PIP) is located in the mucosa of the small bowel. We hypothesized that PIP may be useful as a marker for early intestinal ischemia or other acute processes of the mucosa. To test this hypothesis we developed a model of acute reversible intestinal ischemia in the pig. Following isolation of a 100-cm segment of ileum on a vascular pedicle baseline, serum and tissue samples were obtained. The vessels were then occluded for 60 min and the segment was reperfused. Serial serum samples were taken and analyzed for PIP and hexosaminidase (HEX). HEX enzyme activity in serum is known to be elevated in animals having intestinal necrosis. The Student t test for paired data was used. In preliminary studies we found that circulating HEX activity became elevated following 3 to 4 hr of vessel occlusion followed by reperfusion. In the current experiments, following 1 hr of ischemia, PIP rose significantly in the peripheral circulation, being 153.8 ± 76.8, 909.0 ± 150.4, and 898.3 ± 128.1 ng/ml ( P < 0.001) at 0, 60, and 360 min after reperfusion of the segment. HEX on the other hand did not change significantly throughout the experiment, having been 766.0 ± 28.1, 752.0 ± 71.3, and 780.1 ± 53.7 n M/liter (ns) at 0, 60, and 360 min following reperfusion of the segment. Histology demonstrated some clubbing, shortening and fracturing of villi with thinning of the tips of the villi in many cases. Immunospecific staining for PIP was present along the intact borders of the villi. These findings suggest that PIP is released into the circulation following a relatively mild mucosal injury and therefore may be a useful biochemical marker for intestinal ischemia prior to intestinal necrosis.