Platelet disturbances correlate with endothelial cell activation in uncomplicated Plasmodium vivax malaria

PLoS Negl Trop Dis. 2020 Jul 20;14(7):e0007656. doi: 10.1371/journal.pntd.0007656. eCollection 2020 Jul.

Abstract

Platelets drive endothelial cell activation in many diseases. However, if this occurs in Plasmodium vivax malaria is unclear. As platelets have been reported to be activated and to play a role in inflammatory response during malaria, we hypothesized that this would correlate with endothelial alterations during acute illness. We performed platelet flow cytometry of PAC-1 and P-selectin. We measured platelet markers (CXCL4, CD40L, P-selectin, Thrombopoietin, IL-11) and endothelial activation markers (ICAM-1, von Willebrand Factor and E-selectin) in plasma with a multiplex-based assay. The values of each mediator were used to generate heatmaps, K-means clustering and Principal Component analysis. In addition, we determined pair-wise Pearson's correlation coefficients to generate correlation networks. Platelet counts were reduced, and mean platelet volume increased in malaria patients. The activation of circulating platelets in flow cytometry did not differ between patients and controls. CD40L levels (Median [IQ]: 517 [406-651] vs. 1029 [732-1267] pg/mL, P = 0.0001) were significantly higher in patients, while P-selectin and CXCL4 showed a nonsignificant trend towards higher levels in patients. The network correlation approach demonstrated the correlation between markers of platelet and endothelial activation, and the heatmaps revealed a distinct pattern of activation in two subsets of P. vivax patients when compared to controls. Although absolute platelet activation was not strong in uncomplicated vivax malaria, markers of platelet activity and production were correlated with higher endothelial cell activation, especially in a specific subset of patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Platelets / cytology*
  • Blood Platelets / metabolism
  • CD40 Ligand / genetics
  • CD40 Ligand / metabolism
  • E-Selectin / genetics
  • E-Selectin / metabolism
  • Endothelial Cells / metabolism
  • Female
  • Humans
  • Intercellular Adhesion Molecule-1 / genetics
  • Intercellular Adhesion Molecule-1 / metabolism
  • Interleukin-11 / genetics
  • Interleukin-11 / metabolism
  • Malaria, Vivax / blood*
  • Malaria, Vivax / genetics
  • Malaria, Vivax / metabolism
  • Male
  • P-Selectin / genetics
  • P-Selectin / metabolism
  • Platelet Activation
  • Platelet Count
  • Young Adult

Substances

  • E-Selectin
  • Interleukin-11
  • P-Selectin
  • Intercellular Adhesion Molecule-1
  • CD40 Ligand

Grants and funding

This worked was funded by the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP under grants #2012/16525-2 and #2017/18611-7 received by FTMC. JCKS has a scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) as an MD/PhD Student. JLSF has a scholarship from FAPESP (#2916/12855-9) as a Pos-Doctoral researcher. HN, MVGL, EVP and FTMC are Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) research fellows. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.