title: Serum levels of vasoactive intestinal peptide as a prognostic marker in early arthritis.
abstract: OBJECTIVE
  Suitable biomarkers are essential for the design of therapeutic strategies in personalized medicine. Vasoactive intestinal peptide (VIP) has demonstrated immunomodulatory properties in autoimmune murine and ex vivo human models. Our aim was to study serum levels of VIP during the follow-up of an early arthritis (EA) cohort and to analyze its value as a biomarker predicting severity and therapeutic requirements.
  
  
  METHODS
  Data from 91 patients on an EA register were analyzed (76% rheumatoid arthritis (RA), 24% undifferentiated arthritis, 73% women, and median age 54 years; median disease duration at entry, 5.4 months). We collected per protocol sociodemographic, clinical, and therapeutic data. VIP levels were determined by enzyme immunoassay in sera harvested from the 91 patients (353 visits; 3.9 visit/patient) and from 100 healthy controls. VIP values below the 25(th) percentile of those assessed in healthy population were considered low. To determine the effect of independent variables on VIP levels, we performed a longitudinal multivariate analysis nested by patient and visit. A multivariate ordered logistic regression was modeled to determine the effect of low VIP serum levels on disease activity at the end of follow-up.
  
  
  RESULTS
  VIP concentrations varied considerably across EA patients. Those fulfilling the criteria for RA had the lowest values in the whole sample, although no significant differences were observed compared with healthy donors. Disease activity, which was assessed using DAS28, inversely correlated with VIP levels. After a two-year follow-up, those patients with low baseline levels of VIP displayed higher disease activity and received more intensive treatment.
  
  
  CONCLUSIONS
  Patients who are unable to up-regulate VIP seem to have a worse clinical course despite receiving more intense treatment. Therefore, measurement of VIP levels may be suitable as a prognostic biomarker.
authors.affiliation: Departamento de Biología Celular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Martínez
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria la Princesa, Madrid, Spain.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Ortiz
authors.affiliation: Departamento de Biología Celular, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Yasmina
authors.initials: Y
authors.lastname: Juarranz
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria la Princesa, Madrid, Spain.
authors.forename: Amalia
authors.initials: A
authors.lastname: Lamana
authors.affiliation: Departamento de Biología Celular, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Iria V
authors.initials: IV
authors.lastname: Seoane
authors.affiliation: Departamento de Biología Celular, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Leceta
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria la Princesa, Madrid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: García-Vicuña
authors.affiliation: Departamento de Biología Celular, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Rosa P
authors.initials: RP
authors.lastname: Gomariz
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria la Princesa, Madrid, Spain.
authors.forename: Isidoro
authors.initials: I
authors.lastname: González-Álvaro
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000097:blood* / Q000175:diagnosis*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D012720:Severity of Illness Index; D014660:Vasoactive Intestinal Peptide / Q000097:blood*
chemical_list: D015415:Biomarkers; D014660:Vasoactive Intestinal Peptide