Clinical relevance of nitric oxide metabolites and nitrative stress in thrombotic primary antiphospholipid syndrome.
OBJECTIVE
To assess the role of nitrite (NO(2)(-)), nitrate (NO(3)(-)), and nitrative stress in thrombotic primary antiphospholipid syndrome (PAPS).


METHODS
We investigated 46 patients with PAPS: 21 asymptomatic but persistent carriers of antiphospholipid antibodies (PCaPL), 38 patients with inherited thrombophilia (IT), 33 patients with systemic lupus erythematosus (SLE), and 29 healthy controls (CTR). IgG anticardiolipin (aCL), IgG anti-beta(2)-glycoprotein I (anti-ß(2)-GPI), IgG anti-high density lipoprotein (aHDL), IgG anti-apolipoprotein A-I (aApoA-I), crude nitrotyrosine (NT) (an indicator of nitrative stress), and high sensitivity C-reactive protein (CRP) were measured by immunoassays. Plasma nitrite (NO(2)(-)), nitrate (NO(3)(-)), and total antioxidant capacity (TAC) were measured by colorimetric spectroscopic assays.


RESULTS
Average plasma NO(2)(-) was lower in PAPS, PCaPL, and IT (p < 0.0001); average NO(3)(-) was highest in SLE (p < 0.0001), whereas average NT was higher in PAPS and SLE (p = 0.01). In thrombotic PAPS, IgG aCL titer and number of vascular occlusions negatively predicted NO(2)(-) (p = 0.03 and p = 0.001, respectively), whereas arterial occlusions and smoking positively predicted NO(3)(-) (p = 0.05 and p = 0.005), and CRP positively predicted NT (p = 0.004). In the PCaPL group IgG aCL negatively predicted NO(3)(-) (p = 0.03). In the SLE group IgG aCL negatively predicted NO(2)(-) (p = 0.03) and NO(3)(-) (p = 0.02).


CONCLUSIONS
PAPS is characterized by decreased NO(2)(-) in relation to type and number of vascular occlusions and to aPL titers. Nitrative stress and low grade inflammation are linked phenomena in PAPS and may have implications for thrombosis and atherosclerosis.
Ames
Paul R J
PR
Department of Rheumatology, Airedale General Hospital, Steeton, UK. paxmes@aol.com
Batuca
Joana R
JR
Ciampa
Antonio
A
Iannaccone
Luigi
L
Delgado Alves
Jose
J
D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood; D016736:Antiphospholipid Syndrome / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D013312:Stress, Physiological; D013927:Thrombosis / Q000097:blood* / Q000209:etiology
D017152:Antibodies, Antiphospholipid; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide