Effects of fish oil supplementation on eicosanoid production in patients at higher risk for colorectal cancer.

Fish oil supplementation may represent a potential chemopreventive agent for reducing colorectal cancer risk. The mechanism of action of fish oil is unknown but presumed to be related to eicosanoid modification. The purpose of this study was to evaluate the effects of fish oil supplementation on the levels of urinary and rectal eicosanoids. We conducted a randomized, double-blind, controlled trial of 2.5 g of fish oil per day compared with olive oil supplementation over a 6-month period. Study participants had a history of colorectal adenomas. Randomization was stratified based on the gene variant rs174535 in the fatty acid desaturase 1 enzyme (FADS1), which affects tissue levels of arachidonic acid. A total of 141 participants were randomized. Urinary prostaglandin E2 metabolite (PGE-M) was measured at baseline, 3, and 6 months and rectal prostaglandin E2 (PGE2) at baseline and 6 months. Repeated-measures linear regression was used to determine the effect of the intervention on each outcome measure. Overall, fish oil supplementation was found to reduce urinary PGE-M production compared with olive oil (P=0.03). Fish oil did not reduce rectal PGE2 overall; however, it did significantly reduce PGE2 in the subgroup of participants not using aspirin or NSAIDs (P=0.04). FADS1 genotype did not seem to modify effects of fish oil on PGE2 production. We conclude that fish oil supplementation has a modest but beneficial effect on eicosanoids associated with colorectal carcinogenesis, particularly in those not taking aspirin or NSAIDs.

Characterization and analysis of osteopontin-immobilized poly(2-hydroxyethyl methacrylate) surfaces.

A wide array of technologies exist for the characterization and quantification of molecules present at surfaces. We have used several of these experimental and instrumental techniques for the analysis of a novel biomaterial surface. Osteopontin, an extracellular matrix molecule involved in wound-healing processes, has been chosen as a relevant model protein to immobilize onto poly(2-hydroxyethyl methacrylate) [poly(HEMA)]. Electron spectroscopy for chemical analysis and time-of-flight secondary ion mass spectrometry were used to verify the surface chemistry and the presence of protein. Iodination of osteopontin yielded quantitative data supportive of dose-dependent immobilization. Enzyme-linked immunosorbent assay was also used to investigate the presence of osteopontin on poly(HEMA). Finally, the cell adhesive properties of immobilized osteopontin were confirmed by using a bovine aortic endothelial cell adhesion assay. The use of multiple tools to characterize the many facets of a biomaterial surface will undoubtedly improve our understanding of the surface and facilitate the amelioration of in vivo performance.