ADAMTS13 Activity in Dogs with Chronic Enteropathies

Background: Chronic enteropathies (CE) predispose dogs to thromboembolic disease, but the underlying mechanisms are poorly understood. Humans with CE have decreased activity of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), a von Willebrand factor (vWF) cleaving enzyme, and increased circulating vWF. The primary aim of this study is to assess plasma ADAMTS13 activity, vWF antigen (vWF:Ag) concentration, and vWF collagen binding activity (vWF:CBA) in dogs with CE.

Hypotheses: Dogs with CE have reduced plasma ADAMTS13 activity, increased vWF:Ag, and increased vWF:CBA compared to healthy control dogs.

Animals: Twenty privately-owned dogs with CE and 40 healthy dogs were recruited from a specialty hospital population.

Methods: Prospective observational study. Dogs were confirmed to have CE using histopathology. ADAMTS13 activity was measured using a commercially available ELISA kit (DiapharmaⓇ) in 20 dogs with CE and 40 healthy control dogs. Plasma vWF:Ag was assessed in 20 dogs with CE and 20 healthy control dogs. Plasma vWF:CBA was assessed in 19 dogs with CE and 20 healthy control dogs. For statistical analysis, an unpaired t-test was used for normally distributed data and Wilcoxon rank sum was used for non-Gaussian distribution. Significance was set at P < 0.05.

Results: Plasma ADAMTS13 activity and vWF:Ag were not significantly different compared to healthy dogs (P = 0.07, P = 0.16, respectively). Plasma vWF:CBA was significantly decreased compared to healthy dogs (P = 0.007).

Conclusions and clinical relevance: Plasma ADAMTS13 activity was not significantly different in dogs with CE compared to healthy dogs and is unlikely to be the primary mechanism for hypercoagulability associated with CE. Forty-three percent of CE dogs with hypoalbuminemia had ADAMTS13 activity below reference interval. Further studies are warranted to evaluate ADAMTS13 activity in a subset of dogs with CE, including those with protein losing enteropathy and thromboembolism.