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Updated: Jul 6, 2026

Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells
Published on: October 27, 2009
A role for plasmin in platelet aggregation: differential regulation of IGF release from IGF-IGFBP complexes?
Marek Marcinkiewicz1, Phillip V Gordon
1University of Virginia Children's Hospital, Department of Pediatrics, P.O. Box 800386, Charlottesville, VA 22908, USA.
Objectives:
To determine if plasmin differentially augments platelet aggregation through variable efficiencies of IGF-IGFBP complex cleavage.
Methods:
We utilized ADP-triggered platelet aggregation assays to test the effects of IGF-I versus IGF-II in complex with IGFBP-2 or IGFBP-3 upon the efficiency of plasmin (a known IGFBP protease) as a pro-aggregatory stimulus. In vitro proteolysis assays were performed as controls.
Results:
We found that IGF-I complexes augmented platelet-mediated aggregation whereas IGF-II either had no effect (IGFBP-2) or inhibited platelet-mediated aggregation (IGFBP-3). In vitro proteolysis assays of IGFBP-2 and IGFBP-3 using plasmin revealed that three of the four aggregation findings were explained by the disparate efficiencies of IGFBP proteolysis associated with each IGF. Only IGF-II-IGFBP-2 complex resulted in a finding that could not be explained by the concept of differential regulation of plasmin's proteolysis efficiency by the two IGF ligands.
Conclusions:
Our findings demonstrate that the plasmin can differentially modulate platelet aggregation in response to intrinsic heterogeneities within the IGF axis.
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