The effect of increasing the sulfation level of chondroitin sulfate on anticoagulant specific activity and activation of the kinin system.

J Hogwood,G Torri,B Mulloy,P Rigsby,C Page,E Gray,A Naggi,Pablo Garcia De Frutos

doi:10.1371/journal.pone.0193482

Abstract

Oversulfated chondroitin sulfate (OSCS) was identified as a contaminant in certain heparin preparations as the cause of adverse reactions in patients. OSCS was found to possess both plasma anticoagulant activity and the ability to activate prekallikrein to kallikrein. Differentially sulfated chondroitin sulfates were prepared by synthetic modification of chondroitin sulfate and were compared to the activity of OSCS purified from contaminated heparin. Whilst chondroitin sulfate was found to have minimal anticoagulant activity, increasing sulfation levels produced an anticoagulant response which we directly show for the first time is mediated through heparin cofactor II. However, the tetra-sulfated preparations did not possess any higher anticoagulant activity than several tri-sulfated variants, and also had lower heparin cofactor II mediated activity. Activation of prekallikrein was concentration dependent for all samples, and broadly increased with the degree of sulfation, though the di-sulfated preparation was able to form more kallikrein than some of the tri-sulfated preparations. The ability of the samples to activate the kinin system, as measured by bradykinin, was observed to be through kallikrein generation. These results show that whilst an increase in sulfation of chondroitin sulfate did cause an increase in anticoagulant activity and activation of the kinin system, there may be subtler structural interactions other than sulfation at play given the different responses observed.

Highlights

In 2008 there were many adverse events, including fatalities, associated with the administration of certain preparations of heparin [1]
This indicates that activation of the kinin system leading to generation of bradykinin is the likely mechanism of action of the adverse effects seen with oversulfated chondroitin sulfate (OSCS) contaminated heparin
The current study aims were to determine: the specific activities of differentially sulfated chondroitin sulfates by multiple anticoagulant methods, with a particular focus on heparin cofactor II activity; to investigate the correlation between the degree and sulfation pattern with anticoagulant activity of OSCS; and to measure the effect that increasing the sulfation of chondroitin sulfates has on prekallikrein activation and whether generation of bradykinin by OSCS is associated with production of kallikrein

Summary

Introduction

In 2008 there were many adverse events, including fatalities, associated with the administration of certain preparations of heparin [1]. Animal studies using rats and pigs have shown that OSCS can cause a marked drop in blood pressure that could be prevented by administration of a bradykinin receptor antagonist [3, 5, 6]. This indicates that activation of the kinin system leading to generation of bradykinin is the likely mechanism of action of the adverse effects seen with OSCS contaminated heparin

Methods

Results

Discussion

Conclusion