Bonnet monkey model for pancreatic changes in induced malnutrition.

Pancreatic degenerative lesions of identical nature could be induced in bonnet monkeys (Macaca radiata) fed protein-deficient tapioca or cassava starch-based and corn-starch-based diets for 3 or 5 months. Marked to severe lobular and acinar cell atrophy in animals fed low-protein diets resembled human pancreatic atrophy resulting from protein deficiency. Animals fed low-protein, high-carbohydrate diets showed lesions akin to tropical chronic calculus pancreatopathy with diabetes mellitus. The pancreatic lesions comprised moderate to marked acinar cell atrophy, marked islet hyperplasia or nesidioblastosis with hypertrophy and mucoid metaplasia of the duct epithelium. Mucoid vasculopathy of the pancreatic artery and arterioles was observed in all animals given protein-deficient diets. It was enhanced in those given additional carbohydrate. Identical lesions were observed after using either source of carbohydrate. This excluded the role of toxic factors such as cyanoglycosides or heavy metals from a tapioca source in initiating the lesions. The study establishes monkey models for the spectrum of human pancreatic changes associated with malnutrition owing to protein deficiency and nutritional imbalance with low-protein, high-starch diets. The experiments demonstrate the dual effects of similar diets on the parenchyma and vasculature of the pancreas.