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Is a decrease of microparticles related to improvement of hemostasis after FVIII injection in hemophilia A patients

F Mobarrez1, D Mikovic, A Antovic

  • 1Division of Cardiovascular Medicine, Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden. fariborz.mobarrez@ki.se

Journal of Thrombosis and Haemostasis : JTH
|December 13, 2012
PubMed
Abstract

Insights

Microparticle levels in hemophilia A patients significantly decreased after FVIII treatment, suggesting their role in clot formation. This finding offers new insights into hemophilia A pathophysiology and treatment.

Area of Science:

  • Hematology
  • Hemostasis and Thrombosis
  • Cell Biology

Background:

  • Microparticles (MPs) are cell-derived vesicles implicated in various physiological and pathological processes.
  • Limited data exist regarding the specific role of MPs in hemophilia A, a genetic bleeding disorder.

Purpose of the Study:

  • To investigate the levels and behavior of different MP populations in severe hemophilia A patients undergoing on-demand treatment with Factor VIII (FVIII).
  • To explore the correlation between MP levels and markers of hemostatic activation.

Main Methods:

  • Flow cytometry was used to quantify total MPs (TMPs), platelet MPs (PMPs), endothelial MPs (EMPs), and leukocyte MPs (LMPs) before and after FVIII injection in 18 severe hemophilia A patients.
  • MP levels were compared with endogenous thrombin potential (ETP), overall hemostatic potential (OHP), fibrin gel permeability, and TAFI levels.

Main Results:

  • Circulating TMPs and PMPs significantly decreased post-FVIII treatment, as did EMPs, while LMPs remained unchanged.
  • TMP and PMP levels showed significant inverse correlations with OHP, ETP, fibrin network permeability, TAFI, and FVIII levels.
  • EMP levels correlated with ETP, but LMP levels did not correlate with any hemostatic markers.

Conclusions:

  • On-demand FVIII treatment in hemophilia A patients leads to a reduction in circulating TMPs, PMPs, and EMPs.
  • The inverse correlation between MP counts and hemostatic activation markers suggests MPs may be incorporated into the hemostatic plug at the site of injury following FVIII substitution.

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