Elimination of Intravenously Administered Radiolabelled Antithrombin III and Heparin in Humans

Summary

Antithrombin III was purified from normal plasma by DEAE- Sephadex chromatography and heparin affinity chromatography; the protein was subsequently radiolabelled with ¹²⁵I. ¹²⁵I-anti- thrombin III alone and ¹²⁵I-antithrombin III in the presence of high affinity ³⁵S-heparin fractions were injected into normal humans. ¹²⁵I-radiolabel and protein bound ³⁵S-radioactivity were followed separately. In semilogarithmic plots ¹²⁵I-antithrombin III disappeared according to a double exponential curve with a half-life in the second phase of 56.8 hr in the absence of heparin and of 33.7 hr in the presence of heparin. Protein bound ³⁵S- radioactivity disappeared much faster than the ¹²⁵I-radiolabel. These data support the concept that heparin disappears as free heparin from the equilibrium heparin – antithrombin III ⇄ heparin + antithrombin III. Immuno-reactive antithrombin III decreased from 100% to 85-90% immediately after injection of ¹²⁵I-antithrombin III in the presence of heparin and returned to normal values within 30 min. This suggests that antithrombin III is transiently sequestered, possibly in trimolecular complexes consisting of antithrombin III, heparin and either lipases or other vascular bound proteins.

Keywords

Heparin - Antithrombin III - Turnover of heparin and antithrombin III

• References

• 1 Collen D, Schetz J, De Cock F, Holmer E, Verstraete M. Metabolism of antithrombin III (heparin cofactor) in man: effect of venous thrombosis and heparin administration. Eur J Clin Invest 1977; 7: 27-35
• 2 Worth Estes J. Kinetics of anticoagulant effect of heparin. JAMA 1970; 212: 1492-1495
• 3 De Swart CA M, Nijmeyer B, Roelofs JM M, Sixma JJ. Kinetics of intravenously administered heparin in normal humans. Blood 1982; 60: 1251-1258
• 4 Ceustermans R, Hoylaerts M, De Mol M, Collen D. Preparation characterization and turnover properties of heparin-antithrombin III complexes stabilized by covalent bonds. J Biol Chem 1982; 257: 3401-3408
• 5 Bouma BN, Griffin JH. Human blood coagulation factor XI. Purification, properties and mechanism of activation by activated factor XII. J Biol Chem 1977; 252: 6432-6437
• 6 Weber K, Pringle JR, Osborn M. Measurement of molecular weight by electrophoresis on SDS-acrylamide gel. Meth Enzymol 1972; 26: 3-27
• 7 Marchalonis JJ. An enzymic method for the trace iodination of immunoglobulins and other proteins. Biochem J 1969; 113: 299-306
• 8 Andersson L-O, Barrowcliffe TW, Holmer E, Johnson EA, Sims GE. Anticoagulant properties of heparin fractionated by affinity chromatography on matrix-bound antithrombin III and by gelfiltration. Thromb Res 1976; 9: 575-583
• 9 De Swart CA M, Nijmeyer B, Andersson L-O, Holmer E, Verschoor L, Bouma BN, Sixma JJ. Elimination of high affinity heparin fractions and their anticoagulant and lipase activity. Blood 1984; 4: 836-842
• 10 Yin ET, Wessler S, Stoll PJ. Biological properties of the naturally occurring plasma inhibition to activated factor X. J Biol Chem 1971; 246: 3703-3711
• 11 Jordan R, Beeler D, Rosenberg R. Fractionation of low molecular weight heparin species and their interaction with antithrombin. J Biol Chem 1979; 254: 2902-2913
• 12 Dawes J, Pepper DS. Catabolism of low-dose heparin in man. Thromb Res 1979; 14: 845-860
• 13 Glimelius B, Busch C, Hook M. Binding of heparin on the surface of cultured human endothelial cells. Thromb Res 1978; 12: 773-782
• 14 Mahadoo J, Hiebert L, Jacques LB. Vascular sequestration of heparin. Thromb Res 1978; 12: 79-90
• 15 Assman G, Krauss RM, Frederickson D, Levy RI. Characterization, subcellular localization and partial purification of a heparin-released triglyceride lipase from rat liver. J Biol Chem 1973; 248: 1992-1999
• 16 Marciniak E, Gockerman JP. Heparin-induced decrease in circulating antithrombin III. Lancet 1977; 2: 581-584