A new animal model for studying EUS changes of chronic pancreatitis

Background: Due to difficulty in obtaining pancreatic histology in humans we here report an animal model for studying serial changes of chronic pancreatitis by EUS and correlating it with histology.

Methods: Four hounds (Canine domestics) weighing 60–80 Lbs. EUS performed for baseline images of the pancreas. At laparotomy and duedonotomy, after identification of the pancreatic duct a guide wire was passed into duct. A 5Fr pancreatic stent introduced over the wire into the pancreatic duct and duodenal end of the stent was sutured to the duodenal mucosa. Animals divided into two groups for survival to 2 wk & 4 wk. In each group EUS examination was performed to image the pancreas under anesthesia followed by euthanasia. Pancreas was harvested. Sequential sections perpendicular to the main pancreatic duct and adjacent parenchyma taken from head, body, and tail. A GI pathologist blinded to EUS findings performed detailed analysis of pancreatic sections for changes of pancreatitis and scored the degree of fibrosis, inflammation and edema.

Results: At baseline, the pancreas on EUS appeared homogeneous (a few echogenic septations and echogenic margins of MPD). 2 wk: EUS images of dog pancreas showed changes such as lobularity, increased echogenic septations, visible pancreatic duct side branches, echogenic foci. 4 wk: EUS images of dog pancreas revealed hypoehcoic foci, echogenic foci, dilated PD, lobularity, irregular margins of main PD. There appeared to be correlation between severity of changes by EUS and by histology.

Conclusion: Dog model for chronic pancreatitis as presented appears to be a promising method for studying sequential changes of chronic pancreatitis by EUS and correlating it with pancreatic histology.