The isoprostanes are
prostaglandin
The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...
-like compounds formed ''in vivo'' from the free radical-catalyzed
peroxidation
of
essential fatty acids (primarily
arachidonic acid
Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated arachidic acid found in cupuaçu butter. Its name derives from the New Latin word ''arachi ...
) without the direct action of
cyclooxygenase (COX) enzymes. The compounds were discovered in 1990 by L. Jackson Roberts and Jason D. Morrow in the Division of Clinical Pharmacology at Vanderbilt University.
[
]
These
nonclassical eicosanoids possess potent
biological activity
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...
as
inflammatory mediators that augment the perception of
pain
Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
.
[
] These compounds are accurate markers of
lipid peroxidation
Lipid peroxidation is the chain of reactions of oxidative degradation of lipids. It is the process in which radical (chemistry), free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by ...
in both animal and human models of
oxidative stress.
Elevated levels of isoprostanes are suspected of contributing to increased risk of heart attack in patients taking
Coxibs. Isoprostanes and their metabolites have also been shown to be elevated in the urine of cigarette smokers, and have been suggested as biomarkers of oxidative stress in smokers.
Abundance
Polyunsaturated fatty acids other than arachidonic acid are also vulnerable to reactive oxygen species and produce isoprostanes.
For example, in addition to the four classes of F2-isoprostanes that can arise from
arachidonic acid
Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated arachidic acid found in cupuaçu butter. Its name derives from the New Latin word ''arachi ...
, peroxidation of
eicosapentaenoic acid (EPA) is predicted to lead to the generation of six classes of F3 isoprostanes, α-linolenic and γ-linolenic acids to two classes of E1- and F1-isoprostanes, and
docosahexaenoic acid to eight classes of D4-isoprostanes and eight classes of E4-isoprostanes. Each of the classes comprise up to eight racemic isomers, leading to an astounding number of isoprostane molecules.
[{{cite journal
, author=Janssen LJ
, title=Isoprostanes: an overview and putative roles in pulmonary pathophysiology
, journal=Am. J. Physiol. Lung Cell Mol. Physiol.
, volume=280
, issue=6
, url=http://ajplung.physiology.org/cgi/reprint/280/6/L1067
, pages=L1067–82
, year=2001
, pmid=11350785
, doi=10.1152/ajplung.2001.280.6.L1067
, access-date=2007-11-02
]
See also
*
Neuroprostanes
*
Prostaglandin
The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...
References
Prostaglandins