Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Oxidative stress results from the generation and overaccumulation of reactive oxygen and nitrogen species and has been shown to damage lipoproteins, lipids, DNA, and proteins. Furthermore, oxidative stress may modulate modifications to these lipoproteins and DNA such that endothelial function and inflammatory processes are altered, ultimately resulting in the initiation and progression of atherosclerosis and cardiovascular disease (CVD). Isoprostanes are a series of prostaglandin-like compounds produced via the free-radical catalyzed peroxidation of arachidonic acid, independent of the cyclooxygenase-derived prostaglandins. F2-isoprostanes are considered the "gold standard" test for quantifying lipid peroxidation/oxidative stress in vivo. 15-F2t-isoprostane (15-F2t-IsoP), also referred to as 8-iso-PGF2 alpha or 8-isoprostane F2 alpha, is 1 of the F2-isoprostanes produced in abundance in vivo and has demonstrated potency as a vasoconstrictor within the vasculature of the heart, brain, lung, and kidneys. Generation of 15-F2t-IsoP induces downstream effects including proliferation of vascular smooth muscle cells and release of endothelin. Additional evidence suggests that F2-isoprostanes may increase aspirin resistance to platelet aggregation within platelets and whole blood.
F2-isoprostanes are advantageous over other markers of lipid peroxidation due to their in vivo and in vitro stability and are detectable in a variety of human tissues and biological fluids including plasma, urine, lavage fluid, RBCs, and cerebrospinal fluid. Quantitation of F2-isoprostanes in a random urine specimen is considered to be the most accurate and robust measurement of circulating isoprostanes and is a noninvasive method of assessment.
The assessment of in vivo lipid peroxidation and considered to be an index of systemic oxidative stress over time
Elevated urinary F2-isoprostanes reflect widespread oxidative stress and systemic burden of lipid peroxidation end products. Quantitation of F2-isoprostanes in urine is highly dependent upon the methodology utilized; however, mass spectrometry methods (gas chromatography-mass spectrometry or liquid chromatography-tandem mass spectrometry) assays yield superior sensitivity and analytical specificity compared with immunoassays.
F2-isoprostanes demonstrate superior clinical sensitivity compared to other oxidative stress biomarkers but lack clinical specificity for any particular disease. Pharmacological treatment with antioxidant supplementation, hypoglycemic agents in diabetes, smoking cessation, and weight reduction have all been shown to decrease production of F2-isoprostanes.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
For the most accurate assessment of lipid oxidation status, individuals should not be on aspirin or other nonsteroidal anti-inflammatory drugs, have smoked, or have had acute changes in statin mono- or combination therapies.
Patients should not take nonsteroidal antiinflammatory drugs (NSAIDs) within 72 hours or aspirin within 2 weeks prior to providing a urine specimen for analysis.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
> or =18 years: < or =1.0 ng/mg creatinine
<18 years: not established
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Strobel NA, Fassett RG, Marsh SA, Coombes JS: Oxidative stress biomarkers as predictors of cardiovascular disease. Int J Cardiol 2011;147:191-201
2. Davies SS, Roberts, LJ: F2-isoprostanes as an indicator and risk factor for coronary heart disease. Free Radic Biol Med 2011 Mar 1;50(5):559-566
3. Kontush A, de Faria EC, Chantepie S, Chapman MJ: A normotriglyceridemic, low HDL-cholesterol phenotype is characterized by an elevated oxidative stress and HDL particles with attenuated antioxidative activity. Atherosclerosis 2005;182:277-285
4. Vassale C, Botto N, Andreassi MG, et al: Evidence for enhanced 8-isoprostane plasma levels, as an index of oxidative stress in vivo, for patients with coronary artery disease. Coron Artery Dis 2003 May;14(3):213-218