Craig G Ruaux1, Jörg M Steiner, David A Williams. 1. Gastrointestinal Laboratory, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4474, USA. cruaux@cvm.tamu.edu
Abstract
BACKGROUND: Measurement of proteolytic activity in feces is a traditional method for the diagnosis of exocrine pancreatic insufficiency (EPI). A drawback of this method is the occurrence of falsely low results that may lead to a false-positive diagnosis of EPI. We hypothesized that intestinal loss of serum proteinase inhibitors in protein-losing enteropathy (PLE) may inhibit fecal proteolytic activity and be a potential source of false low results. OBJECTIVE: The objective of this study was to determine the effect of PLE on fecal proteolytic activity in dogs. METHODS: Fecal proteolytic activity was measured using a radial diffusion casein digestion assay in 12 samples from 4 clinically healthy control dogs and 30 samples from 16 dogs with PLE. Gastrointestinal protein loss was assessed using an ELISA to determine fecal canine alpha 1-proteinase inhibitor concentration. The relationship between the concentration of canine alpha 1-proteinase inhibitor in the feces and the diameter cleared in the casein digestion assay was determined. The mean clearing diameter was compared between control dogs and dogs with PLE. RESULTS: A significant negative correlation was observed between fecal canine alpha1-proteinase inhibitor concentration and casein clearing diameter (P <.001, Pearson r =.6317, r2 =.3999). Mean clearing diameter was significantly lower in dogs with PLE than in control dogs (12.63 vs 16.83 mm, P <.001, two-tailed Student's t-test). CONCLUSION: Increased fecal loss of alpha1-proteinase inhibitor in dogs with PLE is associated with a significant decrease in fecal proteolytic activity and may result in a false positive diagnosis of EPI.
BACKGROUND: Measurement of proteolytic activity in feces is a traditional method for the diagnosis of exocrine pancreatic insufficiency (EPI). A drawback of this method is the occurrence of falsely low results that may lead to a false-positive diagnosis of EPI. We hypothesized that intestinal loss of serum proteinase inhibitors in protein-losing enteropathy (PLE) may inhibit fecal proteolytic activity and be a potential source of false low results. OBJECTIVE: The objective of this study was to determine the effect of PLE on fecal proteolytic activity in dogs. METHODS: Fecal proteolytic activity was measured using a radial diffusion casein digestion assay in 12 samples from 4 clinically healthy control dogs and 30 samples from 16 dogs with PLE. Gastrointestinal protein loss was assessed using an ELISA to determine fecal canine alpha 1-proteinase inhibitor concentration. The relationship between the concentration of canine alpha 1-proteinase inhibitor in the feces and the diameter cleared in the casein digestion assay was determined. The mean clearing diameter was compared between control dogs and dogs with PLE. RESULTS: A significant negative correlation was observed between fecal canine alpha1-proteinase inhibitor concentration and casein clearing diameter (P <.001, Pearson r =.6317, r2 =.3999). Mean clearing diameter was significantly lower in dogs with PLE than in control dogs (12.63 vs 16.83 mm, P <.001, two-tailed Student's t-test). CONCLUSION: Increased fecal loss of alpha1-proteinase inhibitor in dogs with PLE is associated with a significant decrease in fecal proteolytic activity and may result in a false positive diagnosis of EPI.
Authors: Silke Salavati Schmitz; Adam Gow; Nick Bommer; Linda Morrison; Richard Mellanby Journal: J Vet Intern Med Date: 2019-08-05 Impact factor: 3.333