M.Sc Thesis

M.Sc StudentAtweh Shehadeh Nardeen
SubjectPlatelet Function in Inflammatory Disorders
DepartmentDepartment of Medicine
Supervisors DR. Lilach Bonstein
PROF. Dale Frank
Full Thesis textFull thesis text - English Version


Background: A growing body of evidence suggests that in addition to their central role in the prevention of bleeding, platelets contribute to diverse processes that extend beyond hemostasis and thrombosis. These contributions include promoting inflammatory and immune responses, maintaining vascular integrity and contributing to wound healing, angiogenesis and cancer metastasis. In response to inflammatory stimuli, platelets convert to their activated form, a process that includes activation of membrane receptors, shape change and degranulation. Hence, markers of platelet activation can be used to identify inflammatory conditions. Aim: To establish a platelet activation assay as an assessment tool for inflammatory conditions. Methods: Expression of platelet activation markers P-selectin and PAC-1 were evaluated in rheumatologic patients and healthy controls using a whole blood flow cytometry assay, enzyme-linked immune absorbent assay (ELISA)of plasma P-selectin and CD40 ligand and a new flow cytometry indirect platelet activation assay. Results: A whole blood activation assay by flow cytometry was set up showing a statistically significant increase of platelet activation in the patient population. This was also demonstrated by the elevation of activation markers P-selectin and CD40 ligand in patients’ plasma. The plasma from these patients also significantly increased the activation status of resting platelets from healthy donors as tested by the indirect activation assay. Conclusions: In this work we established a whole blood platelet activation assay in order to use platelet activation as a biomarker and as an assessment tool for the evaluation of inflammatory conditions. In addition, we developed a new indirect platelet activation assay which improved on the whole blood assay by eliminating time restrictions from sampling to testing. This assay enabled not only the use of fresh samples but also the use of frozen plasma samples taken at unlimited time periods or at distant laboratories/hospitals.