Laminin promotes coagulation and thrombus formation in a factor XII-dependent manner.
BACKGROUND
Laminin is the most abundant non-collagenous protein in the basement membrane. Recent studies have shown that laminin supports platelet adhesion, activation and aggregation under flow conditions, highlighting a possible role for laminin in hemostasis.


OBJECTIVE
To investigate the ability of laminin to promote coagulation and support thrombus formation under shear.


RESULTS
Soluble laminin accelerated factor (F) XII activation in a purified system, and shortened the clotting time of recalcified plasma in a FXI- and FXII-dependent manner. Laminin promoted phosphatidylserine exposure on platelets and supported platelet adhesion and fibrin formation in recalcified blood under shear flow conditions. Fibrin formation in laminin-coated capillaries was abrogated by an antibody that interferes with FXI activation by activated FXII, or an antibody that blocks activated FXI activation of FIX.


CONCLUSIONS
This study identifies a role for laminin in the initiation of coagulation and the formation of platelet-rich thrombi under shear conditions in a FXII-dependent manner.
White-Adams
T C
TC
Division of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
Berny
M A
MA
Patel
I A
IA
Tucker
E I
EI
Gailani
D
D
Gruber
A
A
McCarty
O J T
OJ
D001777:Blood Coagulation / Q000502:physiology*; D005174:Factor XII / Q000502:physiology*; D006801:Humans; D007797:Laminin / Q000502:physiology*; D013927:Thrombosis
D007797:Laminin; D005174:Factor XII
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