Citrulline is a nonprotein amino acid synthesized in the small intestine. The aim of this study isto explore plasma citrulline levels in children with celiac disease (CD) and monitor the time-related changes of these levels after initiation of a gluten-free diet (GFD).
Fasting-plasma citrulline levels were determined by high-performance liquid chromatography in (i) 23 patients with CD before the institution of GFD, (ii) 20 patients with CD under treatment for more than 2 years responsive to a GFD, (iii) 10 children with gastrointestinal symptoms and normal small bowel biopsy, and (iv) 20 healthy controls. In group A, citrulline levels were also measured after 1, 3, 6, and 12 months on a GFD.
Mean plasma citrulline levels were lower in untreated patients with CD (24.5±4.9) than in patients onaGFD (31.2±6.7 μmol/l, P<0.001), patients with gastrointestinal symptoms and normal intestinal mucosa (30.3±4.7 μmol/l, P<0.01), and healthy controls (32.4±7.5 μmol/l, P<0.001). In untreated patients with CD,an inverse correlation was observed between citrulline concentrations and the severity of villous atrophy (r=−0.67, P<0.01). After 1 month on a GFD, patients hadsignificantly higher levels than before diet (P<0.05) and after 3 months on diet, levels were similar to those observed in the healthy controls.
Plasma citrulline levels are lower in celiacs reflecting small bowel involvement in this disease. After ashort period on GFD, citrulline levels increased rapidly, indicating that citrulline is a sensitive marker of the positiveeffect of GFD on intestinal repair.