Purpose: Citrulline, a nonprotein amino acid synthesized by enterocytes, is a biomarker of bowel length and the capacity to wean from parenteral nutrition. However, the potentially variant effect of jejunal versus ileal excision on plasma citrulline concentration [CIT] has not been studied. This investigation compared serial serum [CIT] and mucosal adaptive potential after proximal versus distal small bowel resection.
Methods: Enterally fed Sprague-Dawley rats underwent sham operation or 50% small bowel resection, either proximal (PR) or distal (DR). [CIT] was measured at operation and weekly for 8 weeks. At necropsy, histologic features reflecting bowel adaptation were evaluated.
Results: By weeks 6-7, [CIT] in both resection groups significantly decreased from baseline (P<0.05) and was significantly lower than the concentration in sham animals (P<0.05). There was no difference in [CIT] between PR and DR at any point. Villus height and crypt density were higher in the PR than in the DR group (P≤0.02).
Conclusion: [CIT] effectively differentiates animals undergoing major bowel resection from those with preserved intestinal length. The region of intestinal resection was not a determinant of [CIT]. The remaining bowel in the PR group demonstrated greater adaptive potential histologically. [CIT] is a robust biomarker for intestinal length, irrespective of location of small intestine lost.
Keywords: Biological markers; Citrulline; Intestinal adaptation; Intestinal failure; Short bowel syndrome.
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