Hemostatic serine proteinases-thrombin, Factor VIIa, Factor Xa, play the central role in blood coagulation and thrombosis. Activation of coagulation and generation of active proteinases is initiated by tissue factor (TF) that is expressed by cells of the innate immune system and endothelial cells after tissue damage and cell activation induced by trauma, infection, hypoxia and other cell injury. Coagulation and inflammation are the essential part of the defensive host response. These processes have several connecting points account for the associate and/or the interaction between coagulation and inflammation pathways. The first link between these processes is endothelium, which after damage expresses the adhesive proteins (vWF,P-selectin), inductors and receptors, involved in both coagulation and inflammation. The second link is platelets, which stored in and after activation release proteins with procoagulant and proinflammatory properties. The third link is the serine proteinases, which produced for blood coagulation and activate via its specifical receptors--PARs (proteinase activated receptors) the cells of both coagulation and inflammation system thereby controlling these processes. The generation of these proteinases is initiated by tissue factor (TF) which triggers blood coagulation at sites of tissue injury by selective binding of FVIIa. TF/VIIa complexes with substrate--FX that is activated to FXa. TF/VIIa/Xa can activate both the inflammatory responses of endothelial and other cells and also blood coagulation through stimulation of thrombin generation. This review summarizes the latest data on the blood coagulation activation that include generation of active surface for coagulation, generation of hemostatic serine proteinases and its role as signalling molecules that via PARs and other receptors involved in regulation and control of the interaction of blood coagulation and inflammation and illustrates the potential for therapeutic intervention.

To accelerate the healing processes in wound repair, attempts have been repeatedly made to use growth factors including thrombin and its peptide fragments. Unfortunately, the employment of thrombin is limited because of its high liability and pro-inflammatory actions at high concentrations. Some cellular effects of thrombin in wound healing are mediated by the activation of protease activated receptor-1 (PAR-1). The thrombin receptor agonist peptide (TRAP:SFLLRN) activates this receptor and mimics the effects of thrombin, but TRAP is a relatively weak agonist. We speculated that the encapsulated peptide may be more effective for PAR-1 activation than nonimmobilized peptide and developed a novel method for TRAP encapsulation in hydrogel films based on natural and synthetic polymers. The effects of an encapsulated TRAP in composite poly(N-vinyl caprolactam)-calcium alginate (PVCL) hydrogel films were investigated in a mouse model of wound healing. On day 7 the wound sizes decreased by about 60% under TRAP-chitosan-containing PVCL films, as compared with control films without TRAP. In the case of TRAP-polylysine-containing films no significant decrease in wound sizes was found. The fibroblast/macrophage ratio increased under TRAP-containing films on day 3 and on day 7. The number of proliferating fibroblasts increased to 150% under TRAP-chitosan films on day 7 as compared with control films. The number of [3H]-thymidine labeled endothelial and epithelial cells in granulation tissues was also enhanced. Thus, the immobilized TRAP to PVCL-chitosan hydrogel films were found to promote wound healing following the stimulation of fibroblast and epithelial cell proliferation and neovascularization. Furthermore, TRAP was shown to inhibit the secretion of the inflammatory mediator PAF from stimulated rat peritoneal mast cells due to augmentation of NO release from the mast cells. The encapsulated TRAP is suggested to accelerate wound healing due to the anti-inflammatory effects and earlier development of the proliferative phase of wound healing.

Activation of blood coagulation and thrombin formation accompany inflammation, wound healing, atherogenesis, and other processes induced by endothelial injury. Systems of hemostasis and inflammation play an important role in the pathogenesis of acute coronary syndromes. This paper reviews thrombin functions involved in its interaction with PAR family receptors, activation of platelets, endothelial cells, leukocytes, smooth muscle cells, and mast cells. Mechanisms of regulatory effects of thrombin on mast cells associated with nitric oxide release are discussed.

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