Tissue factor-dependent coagulation activation by heme: A thromboelastometry study

PLoS One. 2017 Apr 24;12(4):e0176505. doi: 10.1371/journal.pone.0176505. eCollection 2017.

Abstract

Heme has been characterized as potent trigger of inflammation. In hemostasis, although heme has been shown to both induce and inhibit different compartments of hemostasis, its net effect on the hemostatic balance, and the biological relevance of these effects remain to be determined. Herein we evaluated the effect of heme on hemostasis using a global assay able to generate clinically relevant data in several other complex hemostatic diseases. Citrated whole blood samples from healthy participants were stimulated by heme or vehicle and incubated for 4h at 37°C. Rotational thromboelastometry was immediately performed. The participation of tissue factor in coagulation activation was evaluated using inhibitory antibody. Heme was able of inducing ex vivo coagulation activation in whole blood, affecting predominantly parameters associated with the initial phases of clot formation. This activation effect was at least partially dependent on hematopoietic tissue factor, since the effects of heme were partially abrogated by the inhibition of human tissue factor. In conclusion, using a global hemostasis assay, our study confirmed that heme is able to activate coagulation in whole blood, in a tissue factor-dependent way. These findings could explain the disturbance in hemostatic balance observed in conditions associated with the release of heme such as sickle cell disease.

MeSH terms

  • Blood Coagulation / drug effects
  • Blood Platelets / drug effects*
  • Heme / pharmacology*
  • Hemostasis / drug effects*
  • Humans
  • Thrombelastography*

Substances

  • Heme

Grants and funding

This study was financially supported by Fapesp grants 2013/09319-0, 2014/00984-3 and 2015/24666-3; and CNPq-Brazil grant 2014/457780. The Hematology and Hemotherapy Center—Hemocentro UNICAMP, forms part of the National Institute of Science and Technology of Blood, Brazil (INCT do SangueCNPq / MCT / FAPESP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.