A rapid embedding procedure for the study of platelet interactions with extracellular matrices in a flowing system. Effect of aspirin on platelet activity.

The cultured endothelial cell (EC) is currently used as a model for the study of the interaction of platelets with the vascular wall. Described is a method for rapid quantitative and qualitative evaluation of platelet interactions with extracellular matrices (ECM) produced by human cultured ECs growing on plastic coverslips. Morphometric calculations can be performed on the same perfused coverslips. A very good correlation (r = 0.96) was found between results of a morphometric method en face and those obtained from analysis of cross sections of the perfused coverslips. A shear rate-dependent increase on platelet deposition onto ECMs was observed with both morphometric procedures. The method is sensitive enough to detect drug-related changes of platelet function. An impairment of the interaction of platelets with the ECM was observed when blood obtained from healthy volunteers who took 500 mg aspirin/day for five days was perfused. Aspirin showed a marked effect, decreasing platelet spreading onto the subendothelium (p less than 0.05). The embedding method described benefits from the use of plastic coverslips that are easily detected from the glycol methacrylate compound used for the embedding procedure. Quantitative analysis en face (covered surface) and qualitative evaluation of platelet interactions (contact, adhesive and aggregated platelets) in cross sections are performed on the same coverslip. This embedding procedure provides a useful tool for the study not only of platelet interactions with ECMs but also for the investigation of interactions of blood elements with other cultured cells.