Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015

Reasons for performing study: Infiltrative disease of the intestine is an important cause of weight loss in the horse. Infiltration of inflammatory or neoplastic cells into the intestinal wall and intestinal fibrosis cause changes in the integrity of the intestinal wall. This may lead to altered intestinal permeability which can be measured using the contrast medium iohexol.

Objectives: To determine if iohexol intestinal permeability, as evaluated by serum iohexol concentration, could be used to differentiate between healthy horses and horses with infiltrative disease of the large colon.

Study design: Prospective non-randomised controlled clinical trial.

Methods: Six healthy adult horses and 4 horses with chronic infiltrative disease of the large colon were used in the study. Infiltrative disease was confirmed on post mortem in all cases, and included alimentary lymphoma and mycobacterial granulomatous enterocolitis. Following a 16-h fast, each horse was dosed with 1.0 ml/kg bwt of iohexol as a 10% solution via nasogastric intubation. Blood samples were collected at 0, 30, 60, 120, 180, 240, 300, 360, 420 and 480 min after dosing. Iohexol concentration was determined using HPLC-UV and the differences between the groups were analysed with a repeated measures ANOVA.

Results: There was a statistically significant difference in iohexol serum concentration between the diseased and nondiseased horses (P = 0.001). The overall difference in the mean iohexol concentration between the 2 groups was 6.07 (95% CI 3.19-8.96) μg/ml, however there appeared to be a trend towards increasing difference at later time points (240, 300, 360 min).

Conclusions: The iohexol permeability test has potential as a diagnostic tool for estimation of intestinal permeability in horses with infiltrative intestinal disease. Further studies are warranted to determine whether the test can be used to determine the site of intestinal pathology, predict the prognosis and potentially evaluate the response to treatment.

Acknowledgements: The authors thank Professor Riitta-Mari Tulamo and Professor Thomas Spillmann and the staff of Equine College Ypäjä and the University of Helsinki Equine Teaching Hospital. The cooperation of horse owners is gratefully acknowledged. Ethical animal research: The study protocol was approved by the National Animal Experiment Board of Finland (Eläinkoelautakunta ELLA, Request for Animal Experiments, ref. no. ESAVI-2010-06567/Ym-23). For client-owned animals, owner informed consent was obtained.

Source of funding: This study was funded by the Faculty of Veterinary Medicine, University of Helsinki, Finland. Competing interests: None declared.