Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes

PLoS One. 2017 Mar 1;12(3):e0172718. doi: 10.1371/journal.pone.0172718. eCollection 2017.

Abstract

In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0-38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cell Adhesion / drug effects
  • Cells, Cultured
  • Endothelial Cells / metabolism*
  • Erythrocytes / metabolism
  • Erythrocytes / parasitology*
  • Female
  • Heparin / analogs & derivatives*
  • Heparin / pharmacology
  • Humans
  • Malaria, Falciparum / metabolism*
  • Male
  • Middle Aged
  • Plasmodium falciparum / metabolism*
  • Rosette Formation
  • Trophozoites / metabolism*

Substances

  • sevuparin
  • Heparin

Grants and funding

This study was supported by Thailand Research Fund for The Royal Golden Jubilee Ph.D programme (PHD/0231/2552)—(Main part of the study); this funder had no input on the study design, execution, analysis, or writing of the manuscript. Faculty of Tropical Medicine, Mahidol University, Mahidol-Oxford research unit (MORU), Bangkok, Thailand (this funder had no input on the study design, execution, analysis, or writing of the manuscript) funded by the Wellcome Trust of Great Britain, United Kingdom (this funder had no input on the study design, execution, analysis, or writing of the manuscript), and the Swedish Research Council (VR) (designed the experiments), the Swedish Foundation for Strategic Research (SSF) (designed the experiments), and the Swedish International Development Agency (SIDA) (designed the experiments). Dilaforette AB (designed the experiments, wrote the paper).