Small intestinal MUC2 synthesis in human preterm infants.

Area of Science:

• Biochemistry
• Gastroenterology
• Pediatric Research

Background:

• Mucin 2 (MUC2) forms the protective mucus layer in the intestine.
• MUC2 synthesis rate is a potential indicator of intestinal barrier function.
• Threonine is a key amino acid in the MUC2 peptide backbone.

Purpose of the Study:

• To investigate if systemic threonine is utilized for small intestinal MUC2 synthesis in preterm infants.
• To determine the fractional synthetic rate (FSR) of MUC2 in this population.

Main Methods:

• Seven preterm infants with enterostomy received intravenous [U-(13)C]threonine infusion.
• Small intestinal MUC2 was isolated using ultracentrifugation and chromatography.
• Threonine isotopic enrichment in MUC2 was measured via gas chromatography-mass spectrometry to calculate FSR.

Main Results:

• Systemically administered threonine was confirmed to be incorporated into intestinal MUC2.
• The median MUC2 fractional synthetic rate (FSR) was 67.2% per day.
• This demonstrates rapid MUC2 synthesis in the small intestine of preterm infants.

Conclusions:

• Systemic threonine is efficiently incorporated into MUC2 in the small intestine of preterm infants.
• Mucin 2 exhibits a very high synthesis rate in this vulnerable population.
• These findings highlight the dynamic nature of the intestinal mucus layer and its rapid turnover.