Assessment of omega-fatty-acid-supplemented human platelets for potential improvement in long-term storage
Krishnamurti, C.; Stewart, M.W.; Cutting, M.A.; Rothwell, S.W.
Thrombosis Research 105(2): 139-145
2002
ISSN/ISBN: 0049-3848 PMID: 11958804 Document Number: 541637
Uptake of omega (omega) - 3 fatty acids can influence membrane stability and cell mobility. We investigated the effects of omega - 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) X 100=%RPC; a high %RPC indicates reduced platelet function) were conducted on platelets treated with 1% fish oil (omega - 3); 2% fish oil emulsion or 1% soy oil (omega - 6). Oil treatment of platelets reduced the vWF bead-induced ATP release insignificantly. Addition of omega - 3 agents reduced physical reactivity (%RPC) with the vWF beads by a factor of 1.2 (oil) and 1.9 (emulsion). The omega - 6 oil enhanced reactivity by a factor of 1.7. After washing to remove excess reagent, platelet resuspension was most efficient with the omega - 3 emulsion. Platelet function was higher with the omega - 3 treated platelets (%RPC = 52.3%, omega - 3 oil; 63.3%, omega - 3 emulsion vs. 85%, omega - 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 omega - 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.