Journal ArticleDOI
Thrombin-induced increase in albumin permeability across the endothelium.
Joe G.N. Garcia,Joe G.N. Garcia,Joe G.N. Garcia,Alma Siflinger-Birnboim,Alma Siflinger-Birnboim,Alma Siflinger-Birnboim,Rena Bizios,Rena Bizios,Rena Bizios,Peter J. Del Vecchio,Peter J. Del Vecchio,Peter J. Del Vecchio,John W. Fenton,John W. Fenton,John W. Fenton,Asrar B. Malik,Asrar B. Malik,Asrar B. Malik +17 more
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TLDR
The basis for the increased albumin permeability following the addition of α‐thrombin appears to be a reversible change in endothelial cell shape with formation of intercellular gaps, as well as no morphological evidence of cell lysis.Abstract:
We studied the effect of thrombin on albumin permeability across the endothelial monolayer in vitro. Bovine pulmonary artery endothelial cells were grown on micropore membranes. Morphologic analysis confirmed the presence of a confluent monolayer with interendothelial junctions. Albumin permeability was measured by the clearance of 125I-albumin across the endothelial monolayer. The control 125I-albumin clearance was 0.273 +/- 0.02 microliter/min. The native enzyme, alpha-thrombin (10(-6) to 10(-10) M), added to the luminal side of the endothelium produced concentration-dependent increases in albumin clearance (maximum clearance of 0.586 +/- 0.08 microliter/min at 10(-6) M). Gamma (gamma) thrombin (10(-6) M and 10(-8) M), which lacks the fibrinogen recognition site, also produced a concentration-dependent increase in albumin clearance similar to that observed with alpha-thrombin. Moreover, the two proteolytically inactive forms of the native enzyme, i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin, increased the 125I-albumin clearance (0.610 +/- 0.09 microliter/min and 0.609 +/- 0.02 microliter/min for i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin at 10(-6) M, respectively). Since the modified forms of thrombin lack the fibrinogen recognition and active serine protease sites, the results indicate that neither site is required for increased albumin permeability. The increase in albumin clearance with alpha-thrombin was not secondary to endothelial cell lysis because lactate dehydrogenase concentration in the medium following thrombin was not significantly different from baseline values. There was also no morphological evidence of cell lysis. Moreover, the increase in 125I-albumin clearance induced by alpha-thrombin was reversible by washing thrombin from the endothelium. The basis for the increased albumin permeability following the addition of alpha-thrombin appears to be a reversible change in endothelial cell shape with formation of intercellular gaps.read more
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Signaling Mechanisms Regulating Endothelial Permeability
Dolly Mehta,Asrar B. Malik +1 more
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Stimulation of Endothelial Cell Prostacyclin Production by Thrombin, Trypsin, and the Ionophore A 23187
TL;DR: Production of thrombin at a site of vascular injury could, by stimulating PGI(2) synthesis by endothelial cells adjacent to the injured area, limit the number of platelets involved in the primary hemostatic response and help to localize thrombus formation.
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Human thrombins. Production, evaluation, and properties of alpha-thrombin.
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Synthesis of Prostacyclin from Platelet-derived Endoperoxides by Cultured Human Endothelial Cells
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