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Title: Intestinal trophic effect of enteral arginine is independent of blood flow in neonatal piglets

item Burrin, Douglas - Doug

Submitted to: Pediatric Research
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2008
Publication Date: 4/1/2008
Citation: Puiman, P.J., Stoll, B., Van Goudoever, J.B., Burrin, D.G. 2008. Intestinal trophic effect of enteral arginine is independent of blood flow in neonatal piglets [abstract]. Pediatric Research. E-PAS 635:140.4

Interpretive Summary:

Technical Abstract: Arginine (ARG) is an indispensable amino acid (AA) in neonates and is required for growth. ARG is synthesized by gut epithelial cells and is a precursor for nitric oxide, which stimulates vasodilation and blood flow. Moreover, evidence indicates that ARG may have a protective role in prevention of necrotizing enterocolitis. We hypothesized that enteral ARG is a specific stimulus for neonatal intestinal blood flow and subsequent mucosal growth. Our aim was to establish the trophic effect of ARG compared to other nutrients on intestinal blood flow and mucosal growth in exclusively TPN, and partially enteral fed neonatal piglets. In study 1, neonatal piglets (3 d old) were implanted with vascular and stomach catheters and an ultrasonic flow probe on the superior mesenteric artery (SMA) to measure blood flow. During recovery, piglets were fed either TPN exclusively ,or partially enteral (PEN, 40%) with a milk-replacer formula for 5 d. Pigs then received a daily infusion protocol in a cross-over design that included an intragastric infusion with saline for 1 h baseline, followed by a 3-h infusion with one of following substrates (umol/kg/h): ARG (50, 100, 200, 400, 800), glutamate (GLU, 800), glutamine (GLN, 800), citrulline (CIT, 800) or glucose (GLUC, 800). During the infusion protocol (n=4-8 pigs/group), SMA blood flow was monitored continuously and arterial blood samples were collected at 1 and 4 h. In study 2, piglets (3 d old) were fed TPN plus 20% PEN formula supplemented with either ARG (n=5) or control alanine (ALA, n=5) at 800 umol/kg/h for 4 d. Then pigs were euthanized to sample gut tissue. In study 1, plasma ARG increased dose-dependently with ARG infusion rate in both TPN, PEN pigs (maximal 1 mM), and was higher in PEN than TPN pigs. Baseline SMA Flow was twofold higher in PEN vs TPN pigs. However, neither ARG at any dose nor GLU, GLN, CIT, or GLUC affected SMA flow compared to saline. In study 2, ARG supplementation increased small intestinal weight in the proximal, but not the distal region compared to ALA. SMA blood flow was increased by partial enteral feeding (40%), but was not affected by enteral ARG or other substrates. Feeding ARG with partial enteral nutrition had a trophic effect on the proximal small intestine. Our results suggest that the trophic effect of ARG on the neonatal small intestine is independent of blood flow.