title: Nociceptin and urotensin-II concentrations in critically ill patients with sepsis.
abstract: BACKGROUND
  The systemic inflammatory response to infection (sepsis) involves widespread organ dysfunction, including changes in immune modulation, cardiovascular derangements, and neural activation. Two neuropeptide/receptor systems, nociceptin/orphanin FQ (N/OFQ) which acts at the non-classical opioid receptor NOP and urotensin-II (U-II) which acts at the urotensin receptor (UT), have been implicated in neural, immune, and cardiovascular system function. In this study, we make measurements of these peptides in critically ill patients.
  
  
  METHODS
  Plasma samples from 21 critically ill patients with sepsis were collected over four consecutive days. Plasma N/OFQ and U-II concentrations were determined by radioimmunoassay and compared with biochemical and clinical markers of illness severity, including serum creatinine, bilirubin, platelet and white cell counts, admission APACHE II and serial SOFA scores.
  
  
  RESULTS
  Median (inter-quartile range) admission plasma N/OFQ concentrations in sepsis were higher in patients who died within 30 days (n=4) compared with survivors (n=17); 3.0 (2.5-5.0) vs 1.0 (1.0-2.5) pg ml(-1) (P=0.028). Plasma N/OFQ concentrations were increased in a subgroup of five patients who had undergone major gastrointestinal surgery. There were no significant changes in plasma U-II concentrations. There were no correlations between plasma U-II and N/OFQ concentrations and markers of illness severity and organ system dysfunction.
  
  
  CONCLUSIONS
  Plasma N/OFQ concentrations were increased in critically ill patients with sepsis who had undergone major gastrointestinal surgery and in patients who subsequently died. Further work is required to clarify the significance of plasma N/OFQ concentrations in sepsis.
authors.affiliation: Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Williams
authors.forename: J P
authors.initials: JP
authors.lastname: Thompson
authors.forename: S P
authors.initials: SP
authors.lastname: Young
authors.forename: S J
authors.initials: SJ
authors.lastname: Gold
authors.forename: J
authors.initials: J
authors.lastname: McDonald
authors.forename: D J
authors.initials: DJ
authors.lastname: Rowbotham
authors.forename: D G
authors.initials: DG
authors.lastname: Lambert
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003422:Critical Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018847:Opioid Peptides / Q000097:blood*; D010865:Pilot Projects; D011379:Prognosis; D018805:Sepsis / Q000097:blood*; D014579:Urotensins / Q000097:blood*; D000097629:Nociceptin
chemical_list: D015415:Biomarkers; D018847:Opioid Peptides; D014579:Urotensins; D000097629:Nociceptin; C029677:urotensin II