Long term follow-up of a simplified and less burdened pancreatic duct ligation model of exocrine pancreatic insufficiency in Goettingen Minipigs.

BACKGROUND: Pancreatic duct ligation in a minipig model leads to exocrine pancreatic insufficiency (EPI). This allows the study of digestive processes and pancreatic enzyme replacement therapies. However, detailed descriptions of the surgical procedure, perioperative management, a determination of exocrine pancreatic insufficiency are scarce in the literature. Data of the long-term health status of minipigs upon EPI induction are still not available. Therefore, the present study describes in detail an experimental approach to the induction of exocrine pancreatic insufficiency via pancreatic duct ligation in minipigs and the long term follow up of the animal's health state. METHODS: 14 Goettingen minipigs underwent pancreatic duct ligation via midline laparotomy for the induction of exocrine pancreatic insufficiency. Fecal fat content, fat absorption, chymotrypsin levels, body weight and blood vitamin and glucose levels were determined. RESULTS: Exocrine pancreatic insufficiency was successfully induced in 12 Goettingen minipigs. Two minipigs failed to develop exocrine insufficiency most likely due to undetected accessory pancreatic ducts. All animals tolerated the procedure very well and gained weight within 8 weeks after surgery without requiring pancreatic enzyme replacement therapy. The follow up for approx. 180 weeks showed a stable body weight and health state of the animals with normal blood glucose levels (Table 1). From approx. 130 weeks post pancreatic duct ligation, all animals were supplemented with pancreatic enzymes and vitamins resulting in blood concentrations almost within the reference range. CONCLUSIONS: Pancreatic duct ligation in minipigs is an excellent method of inducing exocrine pancreatic insufficiency. It is important to identify and ligate accessory pancreatic ducts since persistence of accessory ducts will lead to maintenance of exocrine pancreatic function. The EPI model caused no persistent side effects in the animals and has the potential to be used in long-term EPI studies with up to 100 weeks post-OP without supplementation with enzymes and vitamins.

Novel ciliate lipases for enzyme replacement during exocrine pancreatic insufficiency.

AIM AND OBJECTIVES: Exocrine pancreatic insufficiency caused by inflammation or pancreatic tumors results in nutrient malfunction by a lack of digestive enzymes and neutralization compounds. Despite satisfactory clinical results with current enzyme therapies, a normalization of fat absorption in patients is rare. An individualized therapy is required that includes high dosage of enzymatic units, usage of enteric coating, and addition of gastric proton pump inhibitors. The key goal to improve this therapy is to identify digestive enzymes with high activity and stability in the gastrointestinal tract. METHODS: We cloned and analyzed three novel ciliate lipases derived from Tetrahymena thermophila. Using highly precise pH-STAT-titration and colorimetric methods, we determined stability and lipolytic activity under physiological conditions in comparison with commercially available porcine and fungal digestive enzyme preparations. We measured from pH 2.0 to 9.0, with different bile salts concentrations, and substrates such as olive oil and fat derived from pig diet. RESULTS: Ciliate lipases CL-120, CL-130, and CL-230 showed activities up to 220-fold higher than Creon, pancreatin standard, and rizolipase Nortase within a pH range from pH 2.0 to 9.0. They are highly active in the presence of bile salts and complex pig diet substrate, and more stable after incubation in human gastric juice compared with porcine pancreatic lipase and rizolipase. CONCLUSIONS: The newly cloned and characterized lipases fulfilled all requirements for high activity under physiological conditions. These novel enzymes are therefore promising candidates for an improved enzyme replacement therapy for exocrine pancreatic insufficiency.