Serum Citrulline Is A Simple Quantitative Marker for Small Intestinal Enterocytes Mass and Absorption Function in Short Bowel Patients

Abstract

To investigate the clinical significance of serum citrulline in evaluating the remnant small bowel enterocytes mass and absorptive function in short bowel (SB) patients. Serum citrulline concentrations were determined using high-performance liquid chromatography (HPLC) in 22 SBS patients and 33 healthy controls. Five-hour urine D-xylose excretion and digestive protein absorption were measured using HPLC and micro-Kjeldahl method, respectively. Small bowel length and surface area were assessed on X-ray radiograph. Correlations between serum citrulline levels and small bowel length, small bowel surface, and nutritional substrate digestive absorption percentage were analyzed. For six patients receiving bowel rehabilitation therapy, serum citrulline, D-xylose excretion, and intestinal protein absorption were measured pre- and immediately postmanagement, and their correlations were analyzed. Serum citrulline levels were significantly lower in SB patients compared with healthy controls. In SB patients, they correlated well with remnant small bowel length (r = 0.82, P < 0.001), surface area (r = 0.86, P < 0.001), 5-h urine D-xylose excretion (r = 0.56, P = 0.007), and digestive protein absorption (r = 0.48, P = 0.046). The increased percentage of serum citrulline level in six patients receiving rehabilitation therapy followed a trend of correlating with that of intestinal protein absorption (r = 0.79, P = 0.063) and urine D-xylose excretion (r = 0.81, P = 0.053). In patients with short bowel syndrome, serum citrulline is a simple and accurate biomarker for the severity of intestinal failure and may be a candidate marker for the gut-trophic effects of bowel rehabilitation therapies.