Changes in urinary dinor dihydro F2-isoprostane metabolite concentrations,a marker of oxidative stress,during and following asthma exacerbations

To investigate changes in oxidant stress during and following acute asthma exacerbations, this stidy measured 2,3-dinor-5,6-dihydro-15-F_2t-IsoP (F₂-IsoP-M), the major urinary metabolite of 15-F_2t-IsoP, in eight asthmatic adults, during and following an asthma hospitalization. F₂-IsoP-M concentrations at admission and follow-up were significantly higher than discharge (admission median: 4.12 ng/Cr mg, range 1.89–7.8; follow-up: 2.47 ng/Cr mg (1.56–6.86); discharge: 1.42 ng/Cr mg (0.7–4.44); both p<0.01), but not significantly different between admission and follow-up. F₂-IsoP-M concentrations at follow-up were higher than a control group with stable asthma (0.68 ng/Cr mg (0.31–1.5), p=0.0008). In conclusion, asthma exacerbations requiring hospitalization are associated with 6-fold higher urinary F₂-IsoP-M concentrations compared to stable asthmatics. F₂-IsoP-M concentrations decreased significantly during hospitalization, but significant elevations 3 months following hospitalization suggest ongoing oxidative stress despite clinical improvement. Urinary F₂-IsoP-M may be a clinically useful, simple non-invasive systemic measure of oxidative stress in asthmatics, providing information not captured by spirometry or symptoms.