A preliminary study assessing cytokine production following ex vivo stimulation of whole blood with diet in dogs with chronic enteropathy

Edward Hall,Aarti Kathrani

doi:10.1186/s12917-019-1940-7

Abstract

BackgroundEx vivo whole blood stimulation assays (WBSA) have been used to characterize the cytokine response to diet in cats. The present study aimed to use this assay to determine the cytokine response to diets being fed at the time of diagnosis to dogs with chronic enteropathy (CE) and to compare this to a control group of dogs presented for non-gastrointestinal (GI) causes.ResultsDogs with chronic GI signs and dogs presented for non-GI causes were prospectively recruited. For each case, residual blood following diagnostic sampling was placed into heparin. WBSAs were performed using crude extracts of the diet currently being fed and provided by the owner. Supernatants were collected and analyzed for tumor necrosis factor (TNF)-alpha, interleukin (IL)-10 and IL-4 using an enzyme-linked immunosorbent assay. The case group consisted of 22 dogs with CE diagnosed on histopathology of GI biopsy and 9 with suspected CE. The non-GI group consisted of 18 dogs. Of the diets being fed at or prior to diagnosis, hydrolyzed protein diets elicited significantly lower IL-10 and TNF-alpha concentrations compared to commercial intact protein diets in dogs with confirmed or suspected CE (P-value 0.004 and < 0.001, respectively). Six out of 15 dogs with detectable IL-4 concentrations in the confirmed CE group had IL-4 to IL-10 ratios that exceeded the 95% confidence interval (CI) of the mean of the non-GI group (non-GI: 95% CI of IL-4:IL-10 = 0.64–2.71; confirmed CE: IL-4:IL-10 in 6 dogs = mean 22.40, range 2.77–89.11).ConclusionsHydrolyzed protein diets elicited a significantly reduced cytokine response when incubated with patient whole blood ex vivo compared to commercial intact protein diets in dogs with CE. The IL-4 to IL-10 ratio as a marker of dietary responsiveness warrants further investigation, together with assessment of the cytokine response to diet at the intestinal mucosal surface.

Highlights

Ex vivo whole blood stimulation assays (WBSA) have been used to characterize the cytokine response to diet in cats
Diet type and ex vivo whole blood stimulation assays in dogs with confirmed or suspected chronic enteropathy (CE) One-way analysis of variance (ANOVA) comparing the IL-10, tumor necrosis factor (TNF)-alpha and IL-4 concentrations between hydrolyzed protein diets (n = 6), commercial intact protein diets (n = 24) and home-prepared diets (n = 6) in dogs with suspected or confirmed CE showed a significant difference for IL-10 and TNF-alpha concentrations, but not IL-4 concentrations (P-values 0.005, < 0.001 and 0.125, respectively)
Post hoc analysis with Bonferroni showed that hydrolyzed protein diets elicited significantly lower IL-10 and TNFalpha concentrations compared to commercial intact protein diets in dogs with confirmed or suspected CE (IL-10: P-value 0.004; mean; hydrolyzed protein diet– 15.6 pg/mL (0); commercial intact protein diet – 413.66 pg/ mL (248.30), TNF-alpha: P-value < 0.001, hydrolyzed protein diet – 8.18 pg/mL (0.94), commercial intact protein diet – 371.88 pg/mL (188.86))

Summary

Introduction

Ex vivo whole blood stimulation assays (WBSA) have been used to characterize the cytokine response to diet in cats. Dogs with FRE cannot be definitively differentiated from enteropathy requiring steroid treatment based on history, clinical signs, laboratory parameters or the severity of GI endoscopic or intestinal histological lesions and food trial is currently needed to differentiate the two conditions. As the etiology of FRE is unknown, dogs may respond to different dietary strategies necessitating trials with multiple therapeutic diets before this condition can be ruled out. This may result in frustration and be costly for the owner as well as delay other treatment modalities such as steroids, to which the dog may respond. The ability to differentiate FRE from SRE in dogs at the time of diagnosis may help to avoid multiple unnecessary exclusion diet trials

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