Racial Differences in Serum Omega-9 (ω9) Lipid Fatty Acid Composition and Desaturase Activity in Patients with Diabetes Type-II

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 723-745-Lipids: Fatty Liver Disease & Lipodystrophies
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-745
Bryan Anthony Wilson*1, Susan Sergeant2, Priscilla Ivester2, William Hundley2 and Floyd Chilton2
1Wake Forest School of Medicine, Winston Salem, NC, 2Wake Forest School of Medicine
Oleic acid (OA) is a common monounsaturated fat in the human diet. As a major component of olive oil, dietary intake of this monounsaturated fatty acid has been associated with a variety of disease outcomes including decreased risk of developing cardiovascular disease. Previously, we have shown distinct ethnic differences in Omega-6 (ω-6) long chain polyunsaturated fatty acid (LC-PUFA) levels when comparing African Americans (AfrAm) and European Americans (EurAm) and the frequency of genetic variants in genes that enhance ω-6 LC-PUFA synthesis. The ω-6 precusor fatty acid linoleic acid (18:2ω6 LA) can be obtained directly through the diet or from OA via desaturation by a delta-12 fatty acid desaturase in plants. OA (18:1ω9) can be synthesized endogenously from the shorter chain Omega-9 (ω9) fatty acid, stearic acid (18:0ω9) via a desaturation (addition of double bonds) step. Moreover it is believed that the ω6 and ω9 fatty acid pathways, share a similar fatty acid desaturase enzyme (FADS2) that is utilized in producing longer chain ω9 and ω6 fatty acids.  In this study we examined if racial differences also exist in Omega-9 (ω9) fatty acid metabolism and whether those differences altered the metabolic lipid panel and markers of inflammation within a cohort of patients with diabetes. We used gas chromatography to measure the LC-PUFA precursors linoleic acid (18:2ω6, LA) and palmitic acid (16:0ω9, PA), as well as the major ω6/ω9 LC-PUFA products: gamma-linoleic (18:3ω6, GLA), dihomo-gamma linoleic (20:3ω6, DGLA) arachidonic (20:4ω6, AA), adrenic acid (22:4ω6, AdrA), docosapentaenoic (22:5ω6, DPA), stearic acid (18:0ω9, SA), and OA in fasting serum from 33 AfrAm and 112 EurAm with diabetes. Compared to EurAm, AfrAm had higher SA (7.96±0.89 vs 7.23±0.84 p<0.001) and lower OA (19.37 ± 2.17 vs 21.16 ± 2.85 p<0.001). Compared to EurAm, the PUFA product:precursor  ratio was higher in EurAm compared to AfrAm for OA:SA (2.97 ± 0.57 vs 2.47 ± 0.43 p<0.001). Moreover, compared to AfrAm, EurAm had lower mean body mass index (31.58±6.03 vs 35.34±8.32 p<0.05) and diastolic blood pressure (73.69±9.95 vs 78.84±10.34 p<0.05). The PUFA ratio, OA:SA  provides an surrogate measure of fatty acid desaturase 2 (FADS2) activity respectively in LC-PUFA synthesis and suggests enhanced ω9 precursor conversion fatty acid metabolism in EurAm which may be genetically determined. This may lead to the prediction of which individual genotypes may best metabolize and therefore utilize lipid supplements.

Nothing to Disclose: BAW, SS, PI, WH, FC

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: NIH Grants: 5P50AT002782-07 ,3P50AT002782-07S1
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