Journal of Neonatal Biology

Abstract

Citrulline: Is it Ready for Primetime. Its Uses and Limitations in Neonatal Medicine

Malvika Prasad, Malki Miller, Alok Bhutada and Shantanu Rastogi

Citrulline is a non-protein amino acid produced almost exclusively by the gut and present only in small amounts in the diet. Since the gut is the main source of citrulline, it could be used as a potential biomarker of intestinal function. Necrotizing Enterocolitis is an intestinal dysfunction in neonates leading to significant morbidity and mortality. This review discusses the various aspects of intestinal injury and the association of citrulline with bowel disorders, as well as recent developments with citrulline in the pediatric population. As citrulline is directly related to small bowel length, it has been recently shown that its levels are an efficient marker when the active mass of the bowel is affected. This could be used as a prognostic marker for parenteral nutrition weaning and development of enteral tolerance. Lower levels of citrulline are found in preterm neonates with necrotizing enterocolitis and such neonates demonstrate a more prolonged course of the disease. The concomitant increase in citrulline levels along with clinical improvement in neonates and progression of enteral feeds suggest that citrulline levels may be a sensitive marker of intestinal recovery. Studies have shown that citrulline levels are well correlated with the length of the bowel as well as intestinal function. Citrulline levels used as a sensitive biomarker for intestinal absorptive function would be clinically useful in diagnosis of necrotizing enterocolitis and detection of bowel function and recovery from intestinal disorders such as necrotizing enterocolitis, although more studies are needed in newborns affected with these diseases.