title: The plasma kallikrein-kinin system: its evolution from contact activation.
abstract: The plasma kallikrein-kinin system consists of the proteins factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen. It was first recognized as a surface-activated coagulation system that is activated when blood or plasma interacts with artificial surfaces. Although surface-activated contact activation occurs in vivo in the case of tissue destruction or a developing thrombus, the physiologic basis for the activation and function of this system has not been delineated. New investigations indicate that there is a proteolytic pathway on cells for PK activation independent of FXII. This pathway for PK with subsequent FXII activation indicates physiologic activities. These activities include blood pressure regulation and modulation of thrombosis risk independently of hemostasis. Furthermore, they include regulation of endothelial cell proliferation, angiogenesis and apoptosis through a cellular-based, outside-in signaling system. The present characterizations of this system, which incorrectly had been thought to initiate coagulation, represent an evolution of understanding in this field.
authors: Division of Hematology and Oncology, Department of Medicine, Case Western Reserve University and University Hospitals Case Medical Center, 10900 Euclid Avenue, Cleveland, OH 44106, USA. schmaier@case.edu
authors: A H
authors: AH
authors: Schmaier
authors: K R
authors: KR
authors: McCrae
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D001794:Blood Pressure; D001920:Bradykinin / Q000097:blood; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000378:metabolism; D005174:Factor XII / Q000378:metabolism; D015956:Factor XIIa / Q000378:metabolism; D006801:Humans; D019679:Kininogen, High-Molecular-Weight / Q000097:blood*; D018919:Neovascularization, Physiologic; D020842:Plasma Kallikrein / Q000378:metabolism*; D011288:Prekallikrein / Q000378:metabolism; D012039:Regional Blood Flow; D018570:Risk Assessment; D015398:Signal Transduction; D013927:Thrombosis / Q000097:blood / Q000209:etiology
chemical_list: D019679:Kininogen, High-Molecular-Weight; D005174:Factor XII; D011288:Prekallikrein; D020842:Plasma Kallikrein; D015956:Factor XIIa; D001920:Bradykinin