Effect of behavioral stress on platelet reactivity on polymeric surfaces

It is well known that stressful stimuli change blood functions and platelet parameters are altered in humans and animals subjected to stress. We have examined the influences of behavioral stress on the morphological responses of platelets on a standard biomaterial, polyethylene (PE). Male rabbits we re used, Blood was collected from the marginal vein of the ear 2 times per subject: the first sample was used as the baseline; 1 week later, the secon d was preceded in half of the subjects by 20 min of immobilization stress. In vitro adhesion of platelets on the PE was evaluated. The exposure of ani mals to stress induced a dramatic change in platelet morphology and functio ns on the PE: a higher degree of platelet adhesion, increased platelet spre ading, and the appearance of pseudopodia, In the unstressed subjects there were no modifications of the platelets on the PE with respect to the baseli ne. The present experiment emphasizes for the first time the possible probl ems involved with the varying physiological conditions of patients before a nd after any biomaterial application surgery and of subjects who supply the blood for hemocompatibility tests performed on biomaterials. Therefore, in assessments of the performance of different biomaterials, the reactivity o f blood factors in the patients should be considered and the test of blood compatibility should be performed with blood collected from donors in appro priate physiological conditions, (C) 1999 John Wiley & Sons, Inc.