Fish Oil to Prevent Asthma Exacerbations in Patients With ALOX5 Polymorphisms

This study is a single-center, investigator-initiated, randomized, double-blind, placebo-controlled, cross-over trial. A total of 30 subjects will be recruited from the U.C. Davis Asthma Network (UCAN) clinics. Some of the research will be conducted at the USDA-WHNRC (Western Health Nutrition Research Center) here at U.C. Davis.

This clinical trial is designed to study the effects of supplemental intake of eicosapentanoic acid (EPA)-enriched omega-3 polyunsaturated fatty acids (n3-PUFA, fish oil) in a subset of moderate to severe asthmatics, who have a high susceptibility to increased leukotriene production due to a polymorphism in the promoter region of the arachidonate 5-lipoxygenase (ALOX5) gene.

EPA competes with AA and can decrease leukotriene production; thus our central hypothesis is that EPA-enriched n3-PUFA supplements will decrease the production of inflammatory leukotrienes and decrease the number of acute exacerbations of asthma in patients with moderate to severe asthma and that these benefits will be greater in subjects with the "high susceptibility" ALOX5 promoter variants. Our specific aims are to: 1) Determine the prevalence of the "high-susceptibility" ALOX5 pathway gene polymorphisms in a diverse cohort of moderate to severe adult asthmatics, 2) Perform a 32 week (12 wk treatment A - 8 wk washout - 12 wk treatment B), blinded, cross-over design clinical trial, during which we treat 15 "high susceptibility" and 15 "low susceptibility" ALOX5 gene polymorphism asthmatics with n-3 PUFA supplements and placebo, and 3) Determine the baseline level and treatment effect of n-3 PUFA supplements on leukotriene metabolite and inflammatory cytokine production in subjects with the 'high' and 'low' susceptibility genotypes. Patients will be recruited primarily from the UC Davis Asthma Network (UCAN).