Synthesis of Tissue Factor Pathway Inhibitor in Human Synovial Cells and Chondrocytes Makes Joints the Predilected Site of Bleeding in Haemophiliacs

Abstract

Summary:The synthesis of tissue factor pathway inhibitor (TFPI) was investigated in cloned human synovial cells and human chondrocytes. TFPI-specific DNA transcription products of these cells were isolated, and a full-length cDNA of about 1000 base pairs was amplified by reverse transcription and polymerase chain reaction. The amplified DNA was cloned into the vector pUC 18. The TFPI coding sequence was confirmed by double stranded sequencing and was identical with that previously published for human TFPI coding nucleotide sequence frorn human placental cDNA (1).The inhibitory activity of TFPI in the cell medium of cultivated human chondrocytes and cloned human synovial cells was determined by a specific chromogenic Substrate assay of factor Xa activity. The inhibitory activity of TFPI in the medium of human chondrocytes and cloned human synovial cells was 630-720 mU/10 8 cells and 1080-1665 mU/10 8 cells, respectively.In addition, TFPI activity in cell culture media of human chondrocytes and cloned human synovial cells was suppressed by a polyclonal goat anti-TFPI antibody directed against the inhibitory domain I and domain II. In the chromogenic Substrate assay, the anti-TFPl antibody completely suppressed the inhibitory activity of TFPI in the samples.

Detection of the Three Kunitz-Type Single Domains of Membrane-Bound Tissue Factor Pathway Inhibitor (TFPI) by Flow Cytometry

“…The increased factor pathway inhibitor is mainly synthesized by vascu-tissue factor pathway inhibitor activity suggested that lar endothelium, where it is bound to heparan sulphate this inhibitor is involved in the post-heparin anticoaguor glycosaminoglycans (6,7), and by other cells, e. g. lant effect following heparin administration. A heparin megakaryocytes and chondrocytes (8). There are three binding site C-terminal from domain 53 has been posintravascular pools of tissue factor pathway inhibitor, in tulated as a mediator of heparin-induced tissue factor pathway inhibitor release from the cell surface (15).…”

Effect of Cyclosporine A on the Release of Tissue Factor Pathway Inhibitor from Endothelial Cells in Heart Transplant Patients and Cell Culture

“…Among other cell types tissue factor pathway inhibitor has been shown to be expressed by endothelial cells (17,18), megakaryocytes, chondrocytes and synovial cells (19,20). The extrinsic pathway is initiated by the tissue factor/factor VII complex, which is inhibited by tissue factor pathway inhibitor.…”

Tissue Factor Pathway Inhibitor (TFPI): Biochemistry, Genetics, and Implications for Thrombophilia. Tissue Factor Pathway Inhibitor (TFPI): Biochemie, Genetik und Stellenwert für die Thromboseneigung

“…2.5 % are found in thrombocytes, which can be released through thrombin stimulation [25]. It is known that megakaryocytes [26], monocytes [27,28], HepG2 cells [29,30,31], and chondrocytes [32] also produce TFPI. The synthesis of TFPI in human synovial cells and human chondrocytes seems to be part of an important regulation process in the synovial system, which maintains a balance between fibrinolytic and clotting reactions during minimal bleeding and avoids inadequate fibrin deposition on the cartilage surface of the joint.…”

“…In haemophiliacs, factor Xa generation depends exclusively on the factor Vila/tissue factor pathway, since factor VIII or factor IX are deficient. Therefore, the presence of TFPI in the synovial system would seem to be the reason why joints are.the predilected sites of bleeding in patients with haemophilia [32].…”