Abstract
Background: The congenital portosystemic shunts (PSS) is a common vascular anomaly in dogs. Vasoactive intestinal peptide (VIP) is produced in various organs (including the small intestine, large intestine, and pancreas), leading to abdominal vasodilation, increased blood flow, increased pancreatic blood flow, and promotion of pancreatic endocrine and exocrine secretion. However, there have been no reports on the concentration of VIP in the portal and peripheral veins in canine PSS.
Aim: The aim of this pilot study was to evaluate whether dogs with PSS have a different VIP concentration in their portal system in general.
Methods: Six dogs with an extrahepatic portosplenic shunt were included in the study. Blood samples were taken from the saphenous and portal vein during PSS ligation surgery with the Amerid constrictor, to evaluate and compare the VIP concentration in both samples. VIP was measured using a commercial canine enzyme-linked immunosorbent assay kit.
Results: The breeds included Mongrels (n = 2), Norfolk Terriers (n = 1), Miniature Dachshunds (n = 1), and Maltese (n = 2), and their ages were 9.3 ± 6.5 months; the bodyweight was 3.3 ± 0.8 kg. The concentration of VIP in the saphenous vein was 17.75 ± 13.88 pg/mL; in contrast, the concentration of VIP in the portal vein was 29.7 ± 20.29 pg/mL. There was no significant difference in the VIP concentration between veins.
Conclusion: There was no difference in the VIP concentration between the portal and saphenous veins, suggesting non-association between VIP and the absence of portal hypertension PSS.

Key words: Dogs, vasoactive intestinal peptide, portosystemic shunt