The citrulline generation test: proposal for a new enterocyte function test.

Abstract

BACKGROUND:

The amino acid citrulline is mainly produced by enterocytes from conversion of glutamine. As fasting plasma citrulline proved disappointing as a biomarker for enterocyte dysfunction in clinical practice, we propose a citrulline generation test (CGT) to assess enterocyte function.

AIM:

To assess the feasibility of a CGT in healthy subjects and patients with decreased enterocyte mass.

METHODS:

Nineteen healthy subjects, 16 patients with intestinal villous atrophy and nine patients with short bowel syndrome (SBS) were given an oral bolus of 20 g of the dipeptide alanine-glutamine. Subsequent changes in plasma citrulline and other amino acid concentrations were determined using reverse-phase high-performance liquid chromatography.

RESULTS:

Following the oral bolus of alanine-glutamine, plasma citrulline concentrations showed a time dependent rise in healthy subjects of 44 +/- 13% (38-55 micromol/L, P < 0.0001). The slope from baseline plasma citrulline to peak concentrations was 0.22 +/- 0.08, 0.13 +/- 0.04 and 0.09 +/- 0.04 micromol/L/min in healthy subjects, patients with coeliac disease (CeD) and refractory CeD, respectively (healthy subjects vs. CeD P < 0.05, healthy subjects vs. refractory CeD P < 0.001). In patients with SBS, the CGT was able to distinguish between non-adapted and adapted SBS by means of the incremental area under the CGT curve till 90 min (iAUC T90). The iAUC T90 was 447 +/- 179 and 1039 +/- 178 micromol/L/min in non-adapted and adapted SBS, respectively (P = 0.04).

CONCLUSION:

An oral bolus of alanine-glutamine induces a time-dependent rise in plasma citrulline concentration to an extent dependent on the existence of villous atrophy or enterocyte hyperplasia in CeD, and adapted SBS, respectively.

• Authors: J H C Peters, N J Wierdsma, T Teerlink, P A M van Leeuwen, C J J Mulder, A A van Bodegraven
• Journal: Alimentary pharmacology & therapeutics (Aliment Pharmacol Ther) Vol. 27 Issue 12 Pg. 1300-10 (Jun 2008) ISSN: 1365-2036 [Electronic] England
• PMID: 18331613 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Citrulline

Topics

• Adult
• Biomarkers (metabolism)
• Calorimetry
• Celiac Disease (metabolism, therapy)
• Citrulline (administration & dosage, metabolism)
• Cross-Sectional Studies
• Enterocytes (metabolism)
• Female
• Humans
• Intestinal Absorption (physiology)
• Male
• Treatment Outcome