Serum and fecal canine α1-proteinase inhibitor concentrations reflect the severity of intestinal crypt abscesses and/or lacteal dilation in dogs.

Abstract

Gastrointestinal (GI) protein loss, due to lymphangiectasia or chronic inflammation, can be challenging to diagnose. This study evaluated the diagnostic accuracy of serum and fecal canine &#x3b1;1-proteinase inhibitor (c&#x3b1;1PI) concentrations to detect crypt abscesses and/or lacteal dilation in dogs. Serum and fecal c&#x3b1;1PI concentrations were measured in 120 dogs undergoing GI tissue biopsies, and were compared between dogs with and without crypt abscesses/lacteal dilation. Sensitivity and specificity were calculated for dichotomous outcomes. Serial serum c&#x3b1;1PI concentrations were also evaluated in 12 healthy corticosteroid-treated dogs. Serum c&#x3b1;1PI and albumin concentrations were significantly lower in dogs with crypt abscesses and/or lacteal dilation than in those without (both P&#x2009;<0.001), and more severe lesions were associated with lower serum c&#x3b1;1PI concentrations, higher 3 days-mean fecal c&#x3b1;1PI concentrations, and lower serum/fecal c&#x3b1;1PI ratios. Serum and fecal c&#x3b1;1PI, and their ratios, distinguished dogs with moderate or severe GI crypt abscesses/lacteal dilation from dogs with only mild or none such lesions with moderate sensitivity (56-92%) and specificity (67-81%). Serum c&#x3b1;1PI concentrations increased during corticosteroid administration. We conclude that serum and fecal &#x3b1;1PI concentrations reflect the severity of intestinal crypt abscesses/lacteal dilation in dogs. Due to its specificity for the GI tract, measurement of fecal c&#x3b1;1PI appears to be superior to serum c&#x3b1;1PI for diagnosing GI protein loss in dogs. In addition, the serum/fecal c&#x3b1;1PI ratio has an improved accuracy in hypoalbuminemic dogs, but serum c&#x3b1;1PI concentrations should be carefully interpreted in corticosteroid-treated dogs.