title: Citrulline as a biomarker of gastrointestinal toxicity in patients with rectal carcinoma treated with chemoradiation.
abstract: BACKGROUND
  Gastrointestinal toxicity is the principal toxicity of chemoradiation in the treatment of rectal carcinoma. The assessment of this toxicity still relies mostly on the symptoms reported by the patient.
  
  
  METHODS
  Plasma citrulline, serum neopterin and urinary neopterin were followed weekly in 49 patients with rectal carcinoma during chemoradiation.
  
  
  RESULTS
  Citrulline significantly (p<0.05) decreased while serum and urinary neopterin concentrations increased during therapy. Irradiated gut volume correlated significantly inversely with citrulline and positively with urinary neopterin. Statistically significant inverse correlations were also observed between urinary neopterin and plasma citrulline concentrations during the treatment. Urinary neopterin concentrations were significantly higher and citrulline concentrations were lower in patients who experienced grade ≥3 gastrointestinal toxicity.
  
  
  CONCLUSIONS
  Citrulline represents a promising biomarker of gastrointestinal toxicity. Moreover, the volume of irradiated gut correlated with urinary neopterin concentrations and an association was observed between gastrointestinal toxicity evidenced by lower citrulline concentrations and systemic immune activation reflected in increased concentrations of urinary neopterin.
authors.forename: Michaela
authors.initials: M
authors.lastname: Zezulová
authors.forename: Marie
authors.initials: M
authors.lastname: Bartoušková
authors.forename: Eva
authors.initials: E
authors.lastname: Hlídková
authors.forename: Tomáš
authors.initials: T
authors.lastname: Adam
authors.forename: Lenka
authors.initials: L
authors.lastname: Kujovská Krčmová
authors.forename: Barbora
authors.initials: B
authors.lastname: Červinková
authors.forename: Dagmar
authors.initials: D
authors.lastname: Solichová
authors.forename: Miloslava
authors.initials: M
authors.lastname: Zlevorová
authors.forename: Karel
authors.initials: K
authors.lastname: Cwiertka
authors.forename: David
authors.initials: D
authors.lastname: Friedecký
authors.forename: David
authors.initials: D
authors.lastname: Vrána
authors.forename: Bohuslav
authors.initials: B
authors.lastname: Melichar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis* / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D002956:Citrulline / Q000097:blood*; D005260:Female; D005720:Gamma Rays; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D019798:Neopterin / Q000097:blood / Q000652:urine; D050397:Radiotherapy, Intensity-Modulated; D012004:Rectal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D013050:Spectrometry, Fluorescence; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; D002956:Citrulline; D019798:Neopterin