Free fatty acid-induced platelet aggregation: studies with solubilized and nonsolubilized fatty acids

Porcine platelets in vitro and in vivo studies: relevance to human thrombosis research

This review summarizes present knowledge on porcine platelets in vitro and recent studies on in vivo activation of platelets in the pig. There are certain differences compared to human platelets: Platelet aggregation and secretion cannot be achieved by epinephrine, and the arachidonate pathway seems poorly developed in porcine platelets. Genetic models for von Willebrand disease (vWD) and storage pool deficiency (SPD) have been developed in the pig. Several models for the study of in vivo platelet deposition and early thrombus formation have been developed. Platelet radio-labeling techniques (with 111In) have been used extensively. We conclude that the pig seems to be a good choice for the investigation of in vivo platelet activation and deposition based on present knowledge of porcine platelets and on already established animal models.

Activation of bovine platelets induced by long-chain unsaturated fatty acids at just below their lytic concentrations, and its mechanism

The effects of long-chain unsaturated fatty acids such as linoleic acid on bovine platelets were examined. Not only linoleic acid, but also oleic and linolenic acid, at just below the concentrations causing marked cell lysis, induced an absorbance decrease of the platelet suspension in the presence of Ca2+. Since this absorbance decrease was reversed by the addition of EDTA and moreover aggregate formation was found by macroscopic and microscopic observation, it was concluded that unsaturated fatty acids at just below their lytic concentrations caused platelet aggregation. Unsaturated fatty acids also caused release of adenine nucleotides, but there was a lag time between the release and the aggregation, just as with ADP-induced release, suggesting that the aggregation was independent of the release of ADP. It was revealed that this activation of platelets by unsaturated fatty acids was caused by marked Ca2+ uptake into the cytoplasm, resulting from significant membrane perturbation.