Assessment of ω-fatty-acid-supplemented human platelets for potential improvement in long-term storage

Abstract

Uptake of omega (ω)−3 fatty acids can influence membrane stability and cell mobility. We investigated the effects of ω−3 and −6 fatty acids on the hemostatic efficacy of human platelets using an in vivo rabbit bleeding model. In vitro assays such as platelet aggregation, vWF bead-mediated ATP release and platelet adhesion to beads (measured by the residual platelet count [RPC] {free platelet count after reacting with the beads}/{baseline platelet count}×100=%RPC; a high %RPC indicates reduced platelet function) were conducted on platelets treated with 1% fish oil (ω−3); 2% fish oil emulsion or 1% soy oil (ω−6). Oil treatment of platelets reduced the vWF bead-induced ATP release insignificantly. Addition of ω−3 agents reduced physical reactivity (%RPC) with the vWF beads by a factor of 1.2 (oil) and 1.9 (emulsion). The ω−6 oil enhanced reactivity by a factor of 1.7. After washing to remove excess reagent, platelet resuspension was most efficient with the ω−3 emulsion. Platelet function was higher with the ω−3-treated platelets (%RPC=52.3%, ω−3 oil; 63.3%, ω−3 emulsion vs. 85%, ω−6 oil; 82% untreated platelets). Ethyl-palmitate-treated thrombocytopenic rabbits were infused with human platelets. Survival times of the treated platelets, as monitored by flow cytometry (6.2–8.2 h) were comparable to untreated platelets (8.6 h). In the rabbit kidney injury model, blood loss after infusion of the treated platelets was similar to that of saline-infused rabbits (75.3±3.4 g). However, platelets washed prior to infusion reduced blood loss to a value comparable to that of fresh platelets (48.3±5 g). Furthermore, the presence of the infused platelets at the injury site was clearly visualized using FITC-tagged anti CD42a antibody. Thus, the ω−3-based agents protect the platelets from damage during the washing procedure as demonstrated in vitro by improved platelet resuspension, low %RPC, high stimulus-responsive ATP secretion and a reduction in blood loss in vivo.