TRIGLYCERIDE HYDROLYSIS OF SOY OIL VS FISH-OIL EMULSIONS

Background: Fish oil triglycerides (TG) are being considered for use i n IV lipid emulsions, but the characteristics of their lipase-mediated clearance from plasma are largely unknown. Methods: We compared the i n vitro hydrolysis of soy oil long-chain triglyceride emulsions (LCT) and fish oil emulsions (omega-3) using lipoprotein (LPL) and hepatic ( HL) lipases. omega-3 emulsions contained 18% and 28% of total TG fatty acid as eicosapentaenoic acid CEPA) and docosahexanoic acid (DHA), re spectively. Results: Under conditions of maximal hydrolysis, total fre e fatty acid (FFA) release was two- to threefold greater with LCT comp ared with omega-3 emulsions. Also, EPA and DHA together contributed pr oportionally much less than other fatty acids (<20% to FFA released fr om omega-3 emulsions. In mixtures of LCT emulsion with omega-3 emulsio ns, the presence of >20% of omega-3 particles substantially inhibited LCT emulsion hydrolysis (by up to 50%). Conclusions: Our results sugge st that, during infusion of omega-3 emulsions, EPA and DHA may enter c ells as TG or partial glycerides within emulsion particles and not as FFA and that coinfusion of omega-3 emulsion with LCT emulsion at low o mega-3:LCT emulsion ratios (up to 20% of total triglyceride as omega-3 ) will not substantially inhibit LCT hydrolysis.