In vitro activation of the contact (Hageman factor) system of plasma by heparin and chondroitin sulfate E

Abstract

A large number of negatively charged macromolecules, including DNA, glycosaminoglycans, and proteoglycans, were tested as possible activators of the contact (Hageman factor) system in vitro. Activation was assessed by conversion of prekallikrein to kallikrein, as determined by amidolytic assay and by cleavage of 125I-Hageman factor into 52,000- and 28,000-dalton fragments. Of particular interest to these studies, heparin proteoglycan and glycosaminoglycan from rat peritoneal mast cells, and squid chondroitin sulfate E, which is representative of the glycosaminoglycan from cultured mouse bone marrow derived mast cells, induced the reciprocal activation between Hageman factor and prekallikrein. In addition, naturally occurring heparin glycosaminoglycans from pig mucosa, bovine lung, and rat mast cells also induced activation. In contrast, native connective tissue matrix glycosaminoglycans and proteoglycans from several sources were inactive, although when one such chondroitin sulfate was further sulfated in vitro, it gained activity. When the negative charge of the activating agents was blocked by the addition of hexadimethrine bromide, the cleavage of 125I-Hageman factor in the presence of prekallikrein was prevented. The active negatively charged macromolecules induced cleavage of 125I-high molecular weight kininogen in normal plasma but not in Hageman factor-deficient or prekallikrein- deficient plasmas. Reconstitution of prekallikrein-deficient plasma with purified prekallikrein restored the kininogen cleavage upon addition of the active proteoglycans. These results suggest that both heparin from connective tissue mast cells and highly sulfated chondroitin sulfate E from cultured mouse bone marrow derived mast cells (which are considered synonomous with mucosal mast cells) could activate the contact system of plasma subsequent to an activation secretion response.

Thrombin generation: phenotypic quantitation

“…Liu (Hyland Division, Baxter Healthcare Corp, Duarte, CA, USA) and was relipidated in PCPS (25% PS, 75% PC) vesicles by a previously described protocol [43,44]. Corn trypsin inhibitor (CTI) was prepared as described [33]. D‐phenylalanyl‐L‐prolyl‐L‐arginine chloromethyl ketone (FPRck) and biotinylated FPRck were a gift from R. Jenny (Hematologic Technologies, Essex Junction, VT, USA).…”

“…Thrombin generation utilizing the whole blood model developed by this laboratory analyzes the tissue factor pathway of coagulation without the interference of the contact pathway and profiles thrombin generation in a near physiological milieu [33–39]. During our comprehensive studies of healthy individuals, we noted that individual volunteers studied multiple times over the course of 60 months showed similar tissue factor stimulus–thrombin production response curves [15].…”

Increased Activity of Coagulation Factor XII (Hageman Factor) Causes Hereditary Angioedema Type III

“…2])-one of three domains involved in the binding of factor XII to negatively charged surfaces 23 -strongly suggests that the substitution of a neutral threonine residue by a positively charged lysine in this domain may enhance activation of FXII as a consequence of more-effective binding to negatively charged surfaces. 24 Further support for an involvement of FXII in HAE type III is derived from the fact that the expression of FXII is increased by estrogens via estrogen-responsive elements in the promoter region. 10 This may explain why only women are affected in our HAE type III-affected families and why there is a correlation between episodes of angioedema and periods of elevated estrogen-levels-for example, during pregnancy or treatment with oral contraceptives or estrogen-replacement therapy.…”

Heparin‐like anticoagulants in asthma

“…In the contact system cascade, the production of kallikrein precedes the release of bradykinin, a direct and indirect putative mediator in experimental and human anaphyiaxis (3). Contact activators are known to be present in endothelial cells, and heparin itself will activate the contact system (3,7). Therefore, the plasma mobilization of EHM might be considered as a possible initiator, and/or potentiator of contact system activity, possibly preceding anaphyiaxis.…”