{
  "abstract": "Citrulline is an amino acid produced by enterocyte metabolism; thus, plasma concentrations may contribute to assessment of intestinal failure (IF) by reflecting enterocyte mass. 1 Citrulline measurement is routinely performed in a full amino acid profile which includes over 40 other analytes. It is expensive, labour-intensive and sample analysis takes over 2 hours. Other abnormalities may be identified, requiring follow-up investigations.A stand-alone assay for plasma citrulline analysis would overcome these problems, enabling cost-effective investigation of children with IF and short bowel syndrome (SBS). This study reports a novel tandem mass spectrometry (MS/MS) method used to determine whether intestinal rehabilitation (IR) was associated with increased citrulline.Infants and children with SBS associated with prematurity were recruited to MIRACLS (gut microbiota and intestinal rehabilitation: a prospective childhood cohort longitudinal study of short bowel syndrome). The primary outcome measure was full IR, i.e. no parenteral nutrition and full enteral feeds for over 28 days. Blood samples taken for routine assays included plasma citrulline at baseline and on achievement of IR or after one year if still PN dependent.Blood was taken into lithium-heparin tubes, centrifuged within one hour and plasma stored at -80°C until analysis. Plasma was mixed with 13C-citrulline internal standard and centrifuged, the supernatant removed and dried down under nitrogen. Citrulline was butylated and reconstituted in mobile phase for analysis by flow injection mass spectrometry on a Shimadzu 8050 MS/MS system. Analytes were detected by multiple reaction monitoring using transitions m/z 232>119 (citrulline) and m/z 233>119 (internal standard) and quantitated with a calibration curve up to 100 µmol/L. Injection-to-injection time was 1.5 minutes. Plasma citrulline measured in samples taken at baseline and at study end were compared using a paired t-test in two groups: those who achieved IR and those who did not.Eleven participants had citrulline measured at two timepoints so were included in this analysis. Age at recruitment was 3.3 years (0.1 – 11.5 years) [mean(range)], gestation at birth was 29 weeks (23 – 38 weeks) and four were female.Seven patients did not achieve IR during the study, aged 4.9 (0.6 – 11.5) years. Baseline citrulline was 14.6 ± 6.9 µmol/L (mean ± standard deviation), not statistically different from results at study end, 14.7 ± 6.0 µmol/L, p=0.49. Four patients achieved IR aged 0.6 (0.1 – 1.4) years. Citrulline was 15.3 ± 1.4 µmol/L at baseline but increased to 31.1 ± 13.6 µmol/L at study end, p=0.03.A MS/MS method for citrulline analysis was developed that was straightforward, fast, low-cost and avoided identification of non-specific abnormalities. A study in infants with SBS and IF found that achieving IR was associated with increased plasma citrulline.This is a small study from one centre, so further work is required to determine the role of citrulline as a biomarker in paediatric patients SBS and IF. However, this study confirms the suitability of analysis by MS/MS at low cost. It overcomes many of the challenges associated with wide-scale measurement of citrulline encountered in previous studies.Reference Crenn P, Messing B, Cynober L. Citrulline as a biomarker of intestinal failure due to enterocyte mass reduction. Clin Nutr. 2008;27(3):328–39.",
  "authors": [
    {
      "affiliations": [
        "Metabolic and Newborn Screening laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust"
      ],
      "name": "Ann Bowron"
    },
    {
      "affiliations": [
        "Great North Children’s Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust",
        "Faculty of Medical Sciences, Newcastle University"
      ],
      "name": "Jemma Cleminson"
    },
    {
      "affiliations": [
        "Metabolic and Newborn Screening laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust"
      ],
      "name": "Marie Appleton"
    },
    {
      "affiliations": [
        "Metabolic and Newborn Screening laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust"
      ],
      "name": "Rachel Blukert"
    },
    {
      "affiliations": [
        "Faculty of Medical Sciences, Newcastle University"
      ],
      "name": "Christopher Stewart"
    },
    {
      "affiliations": [
        "Department of Neonatology, Newcastle upon Tyne Hospitals NHS Foundation Trust",
        "Translational and Clinical Research Institute, Newcastle University"
      ],
      "name": "Janet Berrington"
    },
    {
      "affiliations": [
        "Great North Children’s Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust",
        "Faculty of Medical Sciences, Newcastle University"
      ],
      "name": "Andrew Gennery"
    },
    {
      "affiliations": [
        "Great North Children’s Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust"
      ],
      "name": "David Campbell"
    }
  ],
  "title": "OC14 Development of a tandem mass spectrometry method for measurement of plasma citrulline for use in the investigation and monitoring of short bowel syndrome",
  "uid": "43e83b0c-5f23-5e4c-83cd-2b66edc47937"
}