Endogenous praecaecal and total tract losses of nitrogen in pancreatic duct-ligated minipigs

Influences of exocrine pancreatic insufficiency on nutrient digestibility, growth parameters as well as anatomical and histological morphology of the intestine in a juvenile pig model

In a pig model, pancreatic duct ligation (PL) leads to a complete loss of exocrine function, causing an exocrine pancreatic insufficiency (EPI) without affecting endocrine function, allowing research of clinical effects and therapy options. This study aimed to investigate effects of experimentally induced EPI in juvenile pigs on digestion and intestinal morphology. Eight female juvenile cross-bred pigs (BW 54.8 kg at the start of the study) were included. Three animals were considered as a control (CON group), and in five animals the ductus pancreaticus accessorius was ligated (PL group). During the 10-week trial period, body weight and body measurements were recorded regularly. At the end of the trial, gastrointestinal tract (GIT) was investigated macroscopically and histologically and weight and digesta samples of individual segments were obtained. The pigs in the CON showed a significantly higher apparent total tract digestibility of crude protein and crude fat (87.8 and 79.9%, respectively) compared to PL (52.4 and 16.6%, respectively). Significant differences were noted in relative weights of duodenum, jejunum and colon (with and without digesta) and also in absolute weights of jejunum and colon. The mean number of nuclei in the transverse section in stratum circulare were significantly higher in all intestinal segments in CON compared to PL. Overall, EPI results in impaired nutrient digestibility with a greater filling of the GIT with digesta. The elongation of the small intestine does not represent "stretching" of the intestine, but rather increased synthesis of intestinal tissue.

Identification of "Digital Sarcopenia" Can Aid the Detection of Pancreatic Exocrine Insufficiency and Malnutrition Assessment in Patients with Suspected Pancreatic Pathology

BACKGROUND

Pancreatic exocrine insufficiency (PEI) and subsequent malnutrition can be difficult to diagnose but lead to sarcopenia and increased mortality and morbidity even in benign disease. Digital skeletal muscle analysis has been increasingly recognised as a tool to diagnose sarcopenia.

OBJECTIVE

The aim of the study was to assess the prevalence of sarcopenia in patients with PEI secondary to benign disease using novel skeletal muscle recognition software.

METHODS

Prospective recruitment of patients referred for endoscopic ultrasound (EUS) with suspected pancreatic pathology. Patients with suspected pancreatic cancer on initial computed tomography (CT) were excluded. The diagnosis of chronic pancreatitis (CP) was based on CT and EUS findings. PEI was assessed with faecal elastase-1. Digital measurement of skeletal muscle mass identified sarcopenia, with demographic and comorbidity data also collected.

RESULTS

PEI was identified in 45.1% (46/102) of patients recruited, and 29.4% (30/102) had changes of CP. Sarcopenia was significantly more prevalent in PEI 67.4% (31/46) than no-PEI 37.5% (21/56) (37.5%), regardless of CP changes (p < 0.003). The prevalence of sarcopenia (67% vs. 35%; p = 0.02) and sarcopenic obesity (68.4% vs. 25%; p = 0.003) was significantly higher when PEI was present without a radiological diagnosis of CP. Multivariate analysis identified sarcopenia and diabetes to be independently associated with PEI (odds ratio 4.8 and 13.8, respectively, p < 0.05).

CONCLUSION

Sarcopenia was strongly associated with PEI in patients undergoing assessment for suspected benign pancreatic pathology. Digital skeletal muscle assessment can be used as a tool to aid identification of sarcopenia in patients undergoing CT scan for pancreatic symptoms.

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.

Metabolic markers of protein maldigestion after a 15N test meal in minipigs with pancreatic exocrine insufficiency

The effect of pancreatic exocrine insufficiency (PEI) on protein malabsorption is little documented, partly due to methodological barriers. We aimed to validate biomarkers of protein malabsorption using a ¹⁵N test meal in a minipig model of PEI. Six pancreatic duct-ligated minipigs were used as a model of PEI and four nonoperated animals as a control. All animals were equipped with an ileocecal reentrant cannula. Minipigs were given a test meal containing [¹⁵N]casein. The PEI animals repeated the test three times, in the absence of any pancreatic enzymes, or after pancreatic substitution at two levels [ A or B: 7,500 or 75,000 (lipase) and 388 or 3881 (protease) FIP U]. Ileal chyme, urine, and blood were collected postprandially. Nitrogen and ¹⁵N were measured in digestive and metabolic pools. We obtained a gradient of ileal protein digestibility from 29 ± 11% in PEI to 89 ± 6% in the controls and a dose- dependent response of enzymes. Insulin and gastric inhibitory polypeptide secretions were decreased by PEI, an effect that was counteracted with the enzymes at level B. The total recovery of ¹⁵N in urinary urea and plasma proteins was 14 ± 5.1% in the control group and decreased to 5.5 ± 2.1% by PEI. It was dose dependently restored by the treatment. Both ¹⁵N recovery in plasma and urine were correlated to protein digestibility. We confirm that the ¹⁵N transfer in those pools is a sensitive marker of protein malabsorption. Nevertheless, an optimization of the test meal conditions would be necessary in the view of implementing a clinical test. NEW & NOTEWORTHY We designed an intervention study to create a gradient of ileal protein digestibility in minipigs with pancreatic exocrine insufficiency and to validate reliable metabolic markers using a ¹⁵N oral meal test. ¹⁵N recovery in plasma proteins and to a higher extent in urine was sensitive to protein malabsorption. This test is minimally invasive and could be used to reveal protein malabsorption in 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.