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Glutamine metabolism in children with short-bowel syndrome: a stable isotope study
R Hankard1, O Goulet, C Ricour
1Service de Gastroentérologie et Nutrition, Hôpital Necker-Enfants-Malades, Paris, France.
Insights
Extensive small-bowel resection in infants reduces glutamine metabolism. This highlights the small intestine's crucial role in infant glutamine utilization and whole-body metabolism.
Area of Science:
- Biochemistry
- Pediatric Gastroenterology
- Metabolic Research
Background:
- Glutamine is a primary fuel source for the developing gastrointestinal tract.
- Altered glutamine metabolism is a concern in infants with short bowel syndrome.
Purpose of the Study:
- To investigate the impact of extensive small-bowel resection on whole-body glutamine metabolism in infants.
- To compare glutamine and leucine metabolism in infants with short bowel syndrome versus healthy controls.
Main Methods:
- Stable isotope infusion (L-[1-13C]leucine and L-[2-15N]glutamine) in postabsorptive infants.
- Measurement of plasma amino acid appearance rates using stable isotope enrichments.
- Comparison between eleven short bowel syndrome infants and four control infants.
Main Results:
- Infants exhibit higher leucine and glutamine fluxes than adults.
- Short bowel syndrome was associated with a significant reduction in glutamine appearance rate.
- Leucine appearance rate remained unchanged in infants with short bowel syndrome.
Conclusions:
- The small intestine plays a significant role in glutamine metabolism in human infants.
- Extensive small-bowel resection alters whole-body glutamine metabolism.
- Findings underscore the importance of the small intestine for infant metabolic homeostasis.
Abstract:
Because glutamine is thought to be a major fuel for developing gut, we tested the hypothesis that extensive small-bowel resection alters whole-body glutamine metabolism in vivo. Eleven infants and children who had undergone extensive small intestinal resection (residual bowel length: 35 +/- 13 cm; mean +/- SD) and four control infants received 4-h primed, continuous i.v. infusions of L-[(1-13C]leucine and L-[2-15N]glutamine in the postabsorptive state. The appearance rates of glutamine and leucine into plasma were determined from stable isotope enrichments in plasma at steady state. We observed the following: 1) Regardless of intestinal status, leucine and glutamine fluxes were higher in infants than values previously reported for adults. 2) Small-bowel resection was associated with a reduction in glutamine appearance rate (568 +/- 124 mumol.kg lean body mass-1.h-1 in short-bowel syndrome infants versus 816 +/- 149 mumol.kg lean body mass-1.h-1 in control infants; p < 0.05). 3) In contrast, leucine appearance rate was unaltered in short-bowel syndrome patients. The findings suggest that the small intestine plays a prominent role in glutamine metabolism in human infants.