The effectiveness of enzymatic replacement therapy measured by turbidimetry and the lipaemic index in exocrine pancreatic insufficient young, growing pigs, fed a high-fat diet

Validation of an omega-3 substrate challenge absorption test as an indicator of global fat lipolysis

INTRODUCTION

The coefficient of fat absorption (CFA) quantifies fat that remains in stool after digestion and is not a direct measure of lipolysis. CFA has been used to assess treatment of pancreatic insufficiency but does not correlate with pancreatic enzyme replacement therapy dose. We explored use of an omega-3 substrate absorption challenge test as a sensitive test of lipolysis and absorption.

METHODS

We studied a novel microbially-derived lipase (SNSP003) employing an established surgical model commonly used to study the uptake of macronutrients, the exocrine pancreatic insufficient pig. Pigs were fed a high-fat diet and given a standardized omega-3 substrate challenge to test the effect of lipolysis on its absorption. Blood was drawn at 0, 1, 2, 4, 6, 8, 12, and 24 hours following the substrate challenge and was analyzed for omega-3 and total fat levels (c14:c24). SNSP003 was also compard to porcine pancrelipase.

RESULTS

The absorption of omega-3 fats was significantly increased following administration of 40, 80 and 120 mg SNSP003 lipase by 51% (p = 0.02), 89%, (p = 0.001) and 64% (p = 0.01), respectively, compared to that observed when no lipase was administered to the pigs, with Tmax at 4 hours. The two highest SNSP003 doses were compared to porcine pancrelipase and no significant differences were observed. Both doses increased plasma total fatty acids (141% for the 80 mg dose (p = 0.001) and 133% for the 120 mg dose (p = 0.006), compared to no lipase) and no significant differences were observed between the SNSP003 lipase doses and porcine pancrelipase.

CONCLUSION

The omega-3 substrate absorption challenge test differentiates among different doses of a novel microbially-derived lipase and correlates with global fat lipolysis and absorption in exocrine pancreatic insufficient pigs. No significant differences were observed between the two highest novel lipase doses and porcine pancrelipase. Studies in humans should be designed to support the evidence presented here that suggests the omega-3 substrate absorption challenge test has advantages over the coefficient of fat absorption test to study lipase activity.

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.

Pancreatic-like enzymes of microbial origin restore growth and normalize lipid absorption in a pig model with exocrine pancreatic insufficiency

INTRODUCTION

The standard therapy for exocrine pancreatic insufficiency (EPI) is porcine-derived pancreatic enzyme replacement therapy (PERT). In the present study we tested a new approach with a mixture of pancreatic-like enzymes of microbial origin (PLEM) in a 1-week efficacy study in EPI pigs. In addition to the conventionally used coefficient of fat and nitrogen absorption (CFA and CNA), parameters that more accurately reflect the nutritional and health status, such as changes in the lipemic index (LI), plasma triglyceride (TG) and non-esterified fatty acid (NEFA) levels, and somatic growth, were determined.

MATERIAL AND METHODS

A PLEM dose containing 120 000 active lipase units, 80 000 active protease units and 12 000 active amylase units (all from Sigma, St. Louis, MO) was given as a powder, twice daily with a meal (40 g fat/meal) to 8 EPI pigs for 7 days. Ten healthy pigs were used as a comparator.

RESULTS

The PLEM enhanced fat and protein digestion, and reversed growth impairment in EPI pigs. With treatment, CFA and CNA increased by 59% and 43% (p < 0.05), respectively. Although fat and protein absorption were lower than in the comparator, the postprandial blood lipid profile was normal as in healthy pigs. The mucosal thickness significantly increased by 27%, 50% and 26%, in the proximal, middle, and distal jejunum (p < 0.05) with treatment and resembled that of healthy animals.

CONCLUSIONS

Pancreatic-like enzymes of microbial origin supported somatic growth and normalized the postprandial lipid profile. As a measure of efficacy, postprandial LI, TG and NEFA are viable endpoints to be explored in human trials.

Black-Box Gastrointestinal Tract-Needs and Prospects of Gaining Insights of Fate of Fat, Protein, and Starch in Case of Exocrine Pancreatic Insufficiency by Using Fistulated Pigs

Exocrine pancreatic insufficiency (EPI) results in the maldigestion and malabsorption of nutrients. The digestive processes in humans and other monogastric species like rat and pig are characterized by a predominantly enzymatic digestion within the small intestine and microbial fermentation located in the hindgut. For protein, it is doctrine that only prececally absorbed amino acids can be transferred to the amino acid pool of the host, while postileal absorption of nitrogen-containing compounds occurs mainly in the form of ammonia, being a burden rather than a benefit for the organism. The pig is an established animal model for humans to study digestive processes. As digestion is markedly impaired in case of EPI the use of an appropriate animal model to study the effects of this disease and to optimize treatment and dietetic measures is of special interest. By using an animal model of experimentally-induced EPI allowing differentiating between digestive processes in the small as well as in the large intestine by use of ileo-cecal fistulated animals, marked effects of EPI on prececal digestion of starch and protein could be shown. The data indicatethat estimation of digestibility of nutrients over the entire digestive tract results in a distinct overestimation of enzymatic digestion of starch and protein. Therefore, this model clearly shows that protein and starch digestion are significantly reduced in case of EPI although this cannot be detected on a fecal level. As postileal fermentation of starch is associated not only with energy losses but also with intensive gas production, this is of special interest to minimize meteorism and improve wellbeing of patients.

The Pancreatic Duct Ligated (Mini)pig as a Model for Pancreatic Exocrine Insufficiency in Man

Modern therapy of pancreatic exocrine insufficiency (PEI) using pancreatic enzyme replacement therapy (PERT) has largely been very effective and has greatly helped in improving the nutritional status of patients with PEI and in increasing the life expectancy in cystic fibrosis. It is believed that the use of predictable large animal models could play an important role in assessing and developing new therapies. This article reviews the pancreatic duct ligated (adult) minipig as a chronic model of total PEI, with a detailed look at the influence of PEI and response to PERT on prececal compared to fecal digestibility, to directly investigate effects on protein and starch digestion and absorption. In addition, the piglet with PEI is reviewed as a model for PEI in young patients with the aim of further improving the therapy and nutritional status of young patients with cystic fibrosis.

Yarrowia lipolytica Lipase 2 Is Stable and Highly Active in Test Meals and Increases Fat Absorption in an Animal Model of Pancreatic Exocrine Insufficiency

BACKGROUND & AIMS

Pancreatic exocrine insufficiency (PEI) reduces pancreatic secretion of digestive enzymes, including lipases. Oral pancreatic enzyme replacement therapy (PERT) with pancreatin produces unsatisfactory results. The lipase 2 produced by the yeast Yarrowia lipolytica (YLLIP2; GenBank: AJ012632) might be used in PERT. We investigated its ability to digest triglycerides in a test meal and its efficacy in reducing fecal fat in an animal model of PEI.

METHODS

YLLIP2 was produced by genetically engineered Y lipolytica and purified from culture media. YLLIP2 or other gastric (LIPF) and pancreatic (PNLIPD) lipases were added to a meal paste containing dietary triglycerides, at a range of pH values (pH 2-7), with and without pepsin or human bile and incubated at 37°C. We collected samples at various time points and measured lipase activities and stabilities. To create an animal model of PEI, steatorrhea was induced by embolization of the exocrine pancreas gland and pancreatic duct ligation in minipigs. The animals were given YLLIP2 (1, 4, 8, 40, or 80 mg/d) or pancreatin (100,000 US Pharmacopeia lipase units/d, controls) for 9 days. We then collected stool samples, measured fat levels, and calculated coefficient of fat absorption (CFA) values.

RESULTS

YLLIP2 was highly stable and poorly degraded by pepsin, and had the highest activity of all lipases tested on meal triglyceride at pH 4-7 (pH 6 with bile: 94 ± 34 U/mg; pH 4 without bile: 43 ± 13 U/mg). Only gastric lipase was active and stable at pH 3, whereas YLLIP2 was sensitive to pepsin hydrolysis after pH inactivation. From in vitro test meal experiments, the lipase activity of YLLIP2 (10 mg) was estimated to be equivalent to that of pancreatin (1200 mg; 100,000 US Pharmacopeia units) at pH 6. In PEI minipigs, CFA values increased from 60.1% ± 9.3% before surgery to 90.5% ± 3.2% after administration of 1200 mg pancreatin (P < .05); CFA values increased to a range of 84.6% ± 3.0% to 90.0% ± 3.8% after administration of 4-80 mg YLLIP2 (P < .05).

CONCLUSIONS

The yeast lipase YLLIP2 is stable and has high levels of activity against test meal triglycerides in a large pH range, with and without bile. Oral administration of milligram amounts of YLLIP2 significantly increased CFA values, similar to that of 1.2 g pancreatin, in a minipig model of PEI.

Monitoring changes in plasma levels of pancreatic and intestinal enzymes in a model of pancreatic exocrine insufficiency--induced by pancreatic duct-ligation--in young pigs

PURPOSE

Plasma levels of pancreatic and intestinal enzymes were measured after pancreatic duct ligation (PDL) to monitor pancreatic exocrine insufficiency (PEI) in a model using young pigs.

MATERIAL/METHODS

Five, 6 week-old pigs (10.9±0.2kg), underwent PDL while age-matched, un-operated pigs were used as controls. Plasma levels of immunoreactive cationic trypsinogen (IRCT), amylase, lipase, and diamine oxidase (DAO) activities were analyzed for 48 days after PDL, including 1 week of oral pancreatic enzyme supplementation (PES) with Creon(®).

RESULTS

PDL resulted in an arrested body growth and a rapid surge of pancreatic enzymes (IRCT, amylase and lipase) into the plasma. Nine days after PDL, the plasma levels of these pancreatic enzymes had decreased. IRCT then remained below the level in un-operated pigs while amylase only fell below control at 25 days. The intestinally derived marker DAO and plasma protein levels were unaffected by PDL but DAO decreased slightly with time in PEI pigs. One-week of oral PES restored body growth, but had little effect on pancreatic enzyme plasma levels, except for a tendency towards increased DAO.

CONCLUSIONS

The study showed that PEI developed within 1-2 weeks after PDL and that only IRCT is a reliable plasma enzyme marker for this. The reduced plasma DAO indicated that PEI also affected the intestines, while PES therapy restored growth of the PDL pigs and slightly increased plasma DAO, suggesting an improved intestinal function.

Stimulating effect of pancreatic-like enzymes on the development of the gastrointestinal tract in piglets

Use of nutritional components from the milk and eventually from the solid feed relates to the growth and development of gastrointestinal tract (GIT). We studied the effect of pancreatic-like enzymes [porcine pancreatic enzymes (Creon) or microbial-derived amylase, protease, and lipase] on GIT morphology and lipid absorption in suckling piglets. Both enzyme preparations, in low or high dose, were fed via a stomach tube twice a day for 7 d starting at 8 d of age and controls received vehicle, n = 6. The day after treatments ended, lipid absorption was tested after which pigs were euthanized and GIT was examined. Enzyme cocktails, irrespective of their origin, increased (P < 0.001) triglyceride level in blood. Enzyme preparation affected (P < 0.001) small intestinal mucosal thickness, villi length, and crypt depth and (P < 0.01) mitotic division of enterocytes. In addition, the external administration of pancreatic enzymes stimulated pancreatic growth as observed by increased (P < 0.05) mitotic division of pancreatic cells. The study revealed that pancreatic or pancreatic-like enzymes of microbial origin administrated in the early postperinatal period enhance GIT development and may be used to better prepare the GIT of piglets for milk use and weaning.

Exogenous pancreatic-like enzymes are recovered in the gut and improve growth of exocrine pancreatic insufficient pigs

The exocrine pancreatic insufficient (EPI) pigs grow less due to different disturbances in feed digestion, absorption, and retention. Use of pancreatic-like enzymes of microbial origin in pigs may improve feed use and performance in slow-growing pigs. The aim was to study gut recovery and effectiveness of pancreatic-like enzymes of microbial origin supplementation on pig performance. Six male pigs 10 to 12 kg BW underwent pancreatic duct ligation surgery to induce total exocrine pancreatic insufficiency (EPI). Three cannulas to access the gastrointestinal tract content were installed in stomach, duodenum, and ileum in EPI pigs and in 3 control (healthy) pigs. One month after surgery, enzymes were given before feeding and digesta samples were collected for analyses. The BW of EPI pigs did not increase during 1 mo following surgery (11.7 vs. 11.6 kg BW); however, BW increased after 1 wk of enzyme supplementation (12.1 kg BW). Coefficient of fat and N absorption increased (P < 0.05) in EPI pigs after enzyme supplementation. Activity of amylase, lipase, and protease in chyme samples of EPI pigs was very low compared to controls. In EPI pigs after enzyme supplementation, amylase activity increased from 5.32 to 72.9 units/mL but remained lower than that of healthy pigs (162.7 units/mL). Lipase activity increased from 79.1 to 421.6 units/mL, which was similar to that of controls (507.3 units/mL). Proteolytic activity increased from 7.8 to 69.7 units/mL but still did not reach control pigs (164.3 units/mL). In conclusion, exogenous microbial enzymes mimic endogenous pancreatic enzymes being recovered along the lumen of the gastrointestinal tract. These enzymes might be a useful tool to stimulate growth of slower-growing pigs after the weaning period.