Metabolic markers of protein maldigestion after a 15N test meal in minipigs with pancreatic exocrine insufficiency.
Am J Physiol Gastrointest Liver Physiol 2017 Oct 26:ajpgi.00218.2017. Epub 2017 Oct 26.
AgroParisTech/INRA/Université Paris Saclay
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 non-operated animals as a control. All animals were equipped with an ileo-caecal re-entrant cannula. Minipigs were given a test meal containing 15N casein. The PEI animals repeated the test 3 times, in the absence of any pancreatic enzymes, or after pancreatic substitution at 2 levels (A or B: 7500 or 75,000 (lipase) and 388 or 3881 (protease) FIP U). Ileal chyme, urine and blood were collected for 10 hours 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 GIP 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 urines 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.