Histopathological picture of pancreatic islets in dogs with congenital portosystemic shunt

Hypoglycemia is frequently found in dogs suffering from portosystemic shunt (PSS). However, the mechanisms leading to abnormal blood glucose concentration in such dogs have not been studied. Therefore, investigations were undertaken to study the structure of pancreatic islets in 25 patients with congenital PSS (cPSS). Material for morphometry and histopathology was taken during the surgical closing of the abnormal blood vessel. A total of 75 islets (3 randomly chosen from each patient) were analyzed, and their average size was compared to reference values for dogs that were considered as 50-325 mu m. The average size of 47 (63%) islets was below 50 mu m, whereas the mean dimension of the largest islet did not exceeded 80 mu m. The average islet size in all patients was 46 (SD 13.3) mu m and in only 2 dogs (8%) all 3 analyzed islets were bigger than the lower reference value. Histopathological examination revealed cytoplasmic vesicles in pancreatic cells, as well as extracellular, homogenous, acidophilic deposits in pancreatic islets. These results indicate that in dogs suffering from cPSS the pancreatic islets are smaller than the reference values and their cells may contain abnormal structures.