Relationship between a Common Variant in the Fatty Acid Desaturase (FADS) Cluster and Eicosanoid Generation in Humans.

Dramatic shifts in theWesterndiet have led to amarkedincrease in the dietary intake of the n-6 polyunsaturated fatty acid (PUFA), linoleic acid (LA). DietaryLAcan then be converted to arachidonic acid (ARA) utilizing three enzymatic steps. Two of these steps are encoded for by the fatty acid desaturase (FADS) cluster (chromosome 11, 11q12.2-q13) and certain genetic variants within the cluster are highly associated withARAlevels.However,nostudy to date has examined whether these variants further influence pro-inflammatory, cyclooxygenase and lipoxygenase eicosanoid products. This study examined the impact of a highly influential FADS SNP, rs174537 on leukotriene, HETE, prostaglandin, and thromboxane biosynthesis in stimulated whole blood. Thirty subjects were genotyped at rs174537 (GG, n = 11; GT, n = 13; TT, n = 6), a panel of fatty acidsfromwholeserumwasanalyzed,andprecursor-to-product PUFA ratios were calculated as a marker of the capacity of tissues (particularly the liver) to synthesize long chain PUFAs. Eicosanoids produced by stimulated human blood were measured by LC-MS/MS.Weobservedanassociationbetweenrs174537andthe ratio of ARA/LA, leukotriene B4, and 5-HETE but no effect on levels of cyclooxygenase products. Our results suggest that variation at rs174537 not only impacts the synthesis of ARA but the overall capacity of whole blood to synthesize 5-lipoxygenase products; these genotype-related changes in eicosanoid levels could have important implications in a variety of inflammatory diseases. [ABSTRACT FROM AUTHOR]