Increased entropy in in vitro activated platelets

Computerized fractal analysis was used in the present work for objective characterization of the entropy of the platelet contour in in vitro stimulated platelets by low level thrombin (0.02 U/ml), collected from healthy individuals and observed by means of transmission electron microscopy. Platelet boundaries were extracted by means of automatically image analysis. Information dimension of the platelet contour (measure of the entropy of the platelet outline) was automatically evaluated. The results showed that the platelet boundary observed by electron microscopy is fractal and that, after an in vitro platelet activation test, the shape of platelets present increased entropy in comparison to the no stimulated platelets (p<0.001), with 100% correct classification. The entropy of the platelet contour observed by transmission electron microscopy provides accurate, quantitative, data to study platelet activation. The results may play important roles in the evaluation of the platelets status in pathological conditions, like as atherosclerosis and diabetes mellitus, where in in vivo activated platelets have been described.