Blood platelets cause retraction of collagen gel.

Human blood platelets cause the collagen gel retraction (CGR) with concomitant exclusion of fluid. CGR is positively related to the number of incorporated platelets and inversely to collagen concentration. Disruption of platelets, EDTA and cytochalasin B inhibit CGR. Platelets from patients with Glanzmann's thrombasthenia are active in CGR. The similarities and differences of CGR and fibrin retraction are discussed.