GTC Biotherapeutics (fka GTCB)

[jessellivermore]

Re the Extrinsic "Coagulation System".

For decades now medical students have been taught there are two operating coagulation cascades: the intrinsic and the extrinsic, the underlying assumption still held in hematology is they are redundant systems with the extrinsic acting as a backup. But what the example of severe hemophilia shows us is the extrinsic system is not capable of functioning effectively to curtail hemmorhage in the absence of the intrinsic system. So it could not be a backup system, because it doesn't work. A fact I have never seen mentioned before. So why is it there???

One possibiity is that the Extrinsic System is designed to function as part of the immune system and not part of the coagulation system. It generates thrombin in areas of tissue damage. The fact fibrin may leak out of the blood stream and be incidentally converted to fibrin may be of secondary importance. Thrombin may play a role activating cells in the immune system to produce chemicals and other effects necessary to minimize the effects of trauma or infection. This is the case with the lymphnode dendritic cells. If this is the case then the design would have certain simularities with the coagulation cascade. The most important would be regulation of the system by thrombin-antithrombin.