Nonclassic eicosanoid

Nonclassic eicosanoids are biologically active signaling molecules made by oxygenation of twenty-carbon fatty acids other than the classic eicosanoids.

Terminology

"Eicosanoid" is the collective^[1] term for oxygenated derivatives of three different 20-carbon essential fatty acids—Eicosapentaenoic acid (EPA), Arachidonic acid (AA) and Dihomo-gamma-linolenic acid (DGLA).

Current usage limits the term to the leukotrienes (LT) and three types of prostanoids—prostaglandins (PG) prostacyclins (PGI), and thromboxanes (TX). However, several other classes can technically be termed eicosanoid, including the eoxins, hepoxilins, resolvins, isofurans, isoprostanes, lipoxins, epi-lipoxins, epoxyeicosatrienoic acids (EETs) and endocannabinoids. LTs and prostanoids are sometimes termed 'classic eicosanoids' ^[2][3][4] in contrast to the 'novel', 'nonclassic' or 'eicosanoid-like' eicosanoids.^[5][6][7][8]

The classic eicosanoids are autocrine and paracrine mediators, active at micromolar concentrations (or lower), produced with high stereospecificity. They are produced from EFAs (chiefly AA) from either cyclooxygenase (COX) or 5-lipoxygenase.

Broadly, the nonclassic eicosanoids are the products of 20-carbon EFAs and ^[9]

• Other oxygenation enzymes, (eoxins, hepoxilins, resolvins, lipoxins, epi-lipoxins, epoxyeicosatrienoic acids (EETs));
• Uncatalyzed oxygenation reactions, (isofurans, isoprostanes, phytoprostanes);
• Addition reactions other than oxygenation (endocannabinoids).

Also included are

• Side products from the classic eicosanoid biosynthesis, (levuglandins, Oxoeicosanoids);
• Reactions between other fatty acids and these pathways (the COX products of pinolenic and mead acid).

See also

• Docosanoids

References

1. Funk, Colin D. (30 November 2001). "Prostaglandins and Leukotrienes: Advances in Eicosanoid Biology". Science 294 (5548): 1871–1875. doi:10.1126/science.294.5548.1871. PMID 11729303. Retrieved 2007-01-08.
2. Van Dyke TE, Serhan CN (2003). "Resolution of inflammation: a new paradigm for the pathogenesis of periodontal diseases". J. Dent. Res. 82 (2): 82–90. doi:10.1177/154405910308200202. PMID 12562878.
3. Serhan CN, Gotlinger K, Hong S, Arita M (2004). "Resolvins, docosatrienes, and neuroprotectins, novel omega-3-derived mediators, and their aspirin-triggered endogenous epimers: an overview of their protective roles in catabasis". Prostaglandins Other Lipid Mediat. 73 (3–4): 155–72. doi:10.1016/j.prostaglandins.2004.03.005. PMID 15290791.
4. Anderle P, Farmer P, Berger A, Roberts MA (2004). "Nutrigenomic approach to understanding the mechanisms by which dietary long-chain fatty acids induce gene signals and control mechanisms involved in carcinogenesis". Nutrition (Burbank, Los Angeles County, Calif.) 20 (1): 103–8. doi:10.1016/j.nut.2003.09.018. PMID 14698023.
5. Evans AR, Junger H, Southall MD, et al. (2000). "Isoprostanes, novel eicosanoids that produce nociception and sensitize rat sensory neurons". J. Pharmacol. Exp. Ther. 293 (3): 912–20. PMID 10869392.
6. O'Brien WF, Krammer J, O'Leary TD, Mastrogiannis DS (1993). "The effect of acetaminophen on prostacyclin production in pregnant women". Am. J. Obstet. Gynecol. 168 (4): 1164–9. doi:10.1016/0002-9378(93)90362-m. PMID 8475962.
7. Behrendt H, Kasche A, Ebner von Eschenbach C, Risse U, Huss-Marp J, Ring J (2001). "Secretion of proinflammatory eicosanoid-like substances precedes allergen release from pollen grains in the initiation of allergic sensitization". Int. Arch. Allergy Immunol. 124 (1–3): 121–5. doi:10.1159/000053688. PMID 11306946.
8. Sarau HM, Foley JJ, Schmidt DB, et al. (1999). "In vitro and in vivo pharmacological characterization of SB 201993, an eicosanoid-like LTB4 receptor antagonist with anti-inflammatory activity". Prostaglandins Leukot. Essent. Fatty Acids 61 (1): 55–64. doi:10.1054/plef.1999.0074. PMID 10477044.
9. Cyberlipid Center. "Prostanoids and Related Products". Retrieved 2007-11-02.