Simultaneous quantification of 8-iso-prostaglandin-F2α and 11-dehydro thromboxane B2 in human urine by liquid chromatography-tandem mass spectrometry

Both F2-isoprostanes (8-iso-PGF2α), a well-known marker of oxidative stress, and thromboxanes A2 (TXA2) are involved in atherosclerosis through LDL oxidation and platelet activation. Different aspects of the pathology can be described by 8-iso-PGF2α and TXA2 so it is important to determine both their concentrations to monitor the disease progression and/or therapy effects. We developed a simple and sensitive method based on liquid chromatography-tandem mass spectrometry, using electrospray ionization in negative-ion mode, for the simultaneous measurement of the concentration of 8-iso-PGF2α and 11-dehydro thromboxane B2 (11-DH-TXB2), a TXA2 metabolite. This method was applied to analyze urine samples collected overnight from 15 atherosclerotic patients, with documented carotid artery sclerosis (CAS), and from 20 controls. The detection limit was 0.097 pg/μL for 8-iso-PGF2α and 0.375 pg/μL for 11-DH-TXB2, with a linear range of 0.78-25 pg/μL; the inter- and intraday imprecision was <5% for both metabolites. These analytes were higher in CAS (P < 0.005 vs controls) and were positively correlated in patients but not in controls, even after adjustment for age and gender (r = 0.60; P = 0.032). This highly sensitive, precise, and rapid method allows for the simultaneous determination of 8-iso-PGF2α and 11-DH-TXB2 in human urine samples in order to evaluate oxidative stress and platelet aggregation.