title: Homocysteine levels in Takayasu arteritis -- a risk factor for arterial ischemic events.
abstract: OBJECTIVE
  To evaluate homocysteine levels in patients with Takayasu arteritis (TA) and in controls, and to analyze associations between homocysteine levels and paraoxonase 1 (PON1) activity, cysteine levels, methotrexate use, disease activity, extent of arterial involvement, and ischemic events in patients with TA.
  
  
  METHODS
  A cross-sectional study was performed with 29 patients with TA and 30 controls who underwent clinical evaluation and blood sample collection in the fasting state.
  
  
  RESULTS
  Among patients with TA, active disease was observed in 9 (31.0%) and previous arterial ischemic events in 10 (34.5%). Therapy with methotrexate was prescribed to 9 (31.0%) patients and it was associated with folic acid in 8 cases. Median homocysteine level was higher in patients with TA [10.9 μmol/l, interquartile range (IQR) 9.6-14.8] than in controls (6.9 μmol/l, IQR 5.1-11.9; p < 0.001). No difference was found regarding mean homocysteine levels between those using methotrexate and those under other therapies (12.8 ± 5.3 μmol/l vs 12.1 ± 3.2 μmol/l, respectively; p = 0.662). TA patients with active disease presented lower homocysteine levels (10.4 ± 2.1 μmol/l) compared to TA patients in remission (13.1 ± 4.2 μmol/l) (p = 0.034). A significant correlation was found between cysteine and homocysteine levels in patients with TA (ρ = 0.676, p < 0.0001), while there was no correlation between homocysteine and PON1 activity (ρ = 0.214, p = 0.265). Median homocysteine levels were higher in patients with ischemic events (13.2 μmol/l, IQR 10.9-17.5) compared to patients with no ischemic events (9.8 μmol/l, IQR 8.7-14.7; p = 0.027) and were associated with arterial ischemia in patients with TA (OR 1.31, 95% CI 1.01-1.71, p = 0.041).
  
  
  CONCLUSIONS
  Patients with TA presented higher homocysteine levels than controls and homocysteine was associated with an increased risk of arterial ischemic events in TA.
authors.affiliation: Rheumatology Division, Universidade Federal de São Paulo/Escola Paulista de Medicina (Unifesp/EPM), São Paulo, Brazil. alexandre_wagner@uol.com.br
authors.forename: Alexandre Wagner Silva
authors.initials: AW
authors.lastname: De Souza
authors.forename: Carla Serrano
authors.initials: CS
authors.lastname: De Lima
authors.forename: Ana Cecilia Diniz
authors.initials: AC
authors.lastname: Oliveira
authors.forename: Luiz Samuel Gomes
authors.initials: LS
authors.lastname: Machado
authors.forename: Frederico Augusto Gurgel
authors.initials: FA
authors.lastname: Pinheiro
authors.forename: Sonia
authors.initials: S
authors.lastname: Hix
authors.forename: Vania
authors.initials: V
authors.lastname: D'Almeida
mesh_terms: D000328:Adult; D043303:Aryldialkylphosphatase / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000097:blood* / Q000201:enzymology / Q000209:etiology; D003430:Cross-Sectional Studies; D003545:Cysteine / Q000097:blood; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D013625:Takayasu Arteritis / Q000097:blood* / Q000150:complications / Q000201:enzymology
chemical_list: D006710:Homocysteine; D043303:Aryldialkylphosphatase; D003545:Cysteine