Abstract Number: PB1783
Meeting: ISTH 2020 Congress
Background: Even though the coagulation cascade is responsible for the formation of clots, other physiological systems, such as the complement system, can influence it. Mannan-binding-lectin (MBL), the initiator of the complement lectin pathway, has been shown to bind to fibrinogen.
To investigate the clotting process under realistic physiological conditions, we have established a microvascular endothelialised whole blood flow model. This model allows the imaging of clot formation in real-time by confocal microscopy.
Aims: The aim of this project was to investigate the role of MBL during clot formation upon vascular injury in a microfluidic bleeding model.
Methods: Endothelial cells were used to create a synthetic vessel in a polydimethylsiloxane mould. Whole blood was then flown through the vessel and an injury was created by rupturing a collagen pouch adjacent to the vessel. The formation of the clot was monitored in real-time with a confocal microscope, fluorescently labelled fibrinogen and antibodies against MBL, fibrin crosslinks, CD41 (platelets), CD62P (activated platelets) and their corresponding secondary antibodies.
Results: Early experiments showed that, after an injury, MBL accumulated outside the vessel in a “wall-like” structure. To determine the exact location of this structure, several antibodies were tested: MBL did not completely co-localize with fibrinogen nor fibrin crosslinks. The same structure was clearly recognizable with platelets (CD41+), but the MBL was not present to the same extent. The only exact co-localization was clearly recognizable with activated platelets (CD62P).
Conclusions: MBL seems to be interacting with activated platelets (CD62P+) during the coagulation reaction, and not only with fibrin as demonstrated before. This discovery might indicate, that platelet activation could initiate the complement system by accumulating MBL when endothelial cells are injured. The microvascular bleeding model is thus an interesting tool to investigate the cellular components during the clotting process.
To cite this abstract in AMA style:Golomingi M, Jenny L, Hardy ET, Lam W, Schroeder V. Complement Mannan-Binding-Lectin Is Associated with Activated Platelets during Clot Formation in a Microfluidic Bleeding Model [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/complement-mannan-binding-lectin-is-associated-with-activated-platelets-during-clot-formation-in-a-microfluidic-bleeding-model/. Accessed January 26, 2022.
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