PB0738 - Complement and Haemostasis: Effects of complement inhibitors in a microfluidic bleeding model

Monday, July 11, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

MG

Murielle Golomingi, MSc

PhD Student
University of Bern
Bern, Bern, Switzerland

Co-Author(s)

JK

Jessie Kohler

MD student
University of Bern
Bern, Bern, Switzerland
CL

Christina Lamers

PostDoc
University of Basel
Basel, Basel-Stadt, Switzerland
RP

Richard Pouw

PostDoc
University of Basel
Basel, Basel-Stadt, Switzerland
Elaissa Trybus Hardy, PhD

Senior Scientist
Department of Pediatrics, Emory University School of Medicine, USA
Atlanta, Georgia, United States
DR

Daniel Ricklin

PI, Research Group Leader
University of Basel
Basel, Basel-Stadt, Switzerland
WL

Wilbur Lam

PI, Research Group Leader
Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta and Department of Pediatrics; Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering
Atlanta, Georgia, United States
Verena Schroeder, PhD

Research Group Leader, PI, Study Director for the Master in Pharmacy
University of Bern
Bern, Bern, Switzerland

Background: Even though the coagulation cascade is responsible for the formation of clots, other physiological systems, such as the complement system, can influence it. There have been several studies on the interactions between the complement system and clot formation, mainly in the context of atherosclerosis, inflammation, and thrombosis. To investigate a potential role of the complement system in the haemostatic response upon vessel injury, we have established a microvascular endothelialised whole blood flow model. This model allows the imaging of clot formation after vessel injury in real-time by confocal microscopy.

Aims: To investigate the role of the complement system 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 P-Selectin (CD62P). The fluorescence signal intensity over time was then compared with and without the following inhibitors targeting complement activation on different levels: inhibitory antibodies anti-C1s, anti-FD and anti-C5, the C3 inhibitor Cp20, and the MASP-1 inhibitor SGMI-1.

Results: We could show so far that inhibition of MASP-1 prolonged the bleeding time after vessel injury, and platelet activation (P-Selectin signal) was lower compared with the control. Preliminary experiments with C1s and FD inhibitory antibodies showed a lower fibrinogen/fibrin signal at the injury site compared with the controls. Experiments with the other inhibitors are underway.

Conclusion(s): Both the bleeding time and markers of clot formation at the injury site suggest an anticoagulant effect of complement inhibition on the clotting process. Further experiments are underway to confirm and extend our results.