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Determination of the Procoagulant Activity of Extracellular Vesicle (EV) Using EV-Activated Clotting Time (EV-ACT)
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Circulating microparticles and procoagulant activity in elderly patients

Anne Forest1, Eric Pautas, Patrick Ray

  • 1Geriatric center, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance-Publique Hôpitaux de Paris, Université Pierre et Marie Curie-Paris 6, 47-83 boulevard de l'hôpital, 75651 Paris cedex 13, France.

The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
|November 28, 2009
PubMed
Abstract

Insights

Elderly individuals show distinct patterns of microparticles (MP) and altered responses to sepsis compared to younger adults. These findings highlight age-related differences in microparticle expression and procoagulant activity during infection.

Area of Science:

  • Gerontology
  • Hematology
  • Immunology

Background:

  • Microparticles (MP) are membrane vesicles linked to procoagulant activity.
  • Aging is associated with a procoagulant state, but the role of MP in this context is not well understood.
  • This study investigates age-related differences in MP expression and procoagulant activity.

Purpose of the Study:

  • To compare microparticle patterns and procoagulant activity in elderly versus young individuals.
  • To examine these differences in both stable and septic conditions.
  • To understand the relationship between microparticles, aging, and infection.

Main Methods:

  • Patients were categorized by age (<50 or ≥75 years) and infection status (present or absent).
  • Circulating microparticles (MPs) were isolated from blood.
  • Cytofluorometry identified MP origins (endothelial, red blood cell, platelet), and procoagulant activity was assessed using annexin V and tissue factor assays.

Main Results:

  • Elderly patients showed decreased endothelial microparticles (EMP) in stable conditions.
  • Septic elderly patients had decreased procoagulant annexin V MPs.
  • Higher EMP levels were observed in elderly infected patients who died compared to survivors, indicating altered responses to sepsis.

Conclusions:

  • Elderly individuals exhibit unique microparticle profiles in stable states.
  • The response to sepsis, particularly in procoagulant activity, is modified in the elderly.
  • These findings suggest age-specific alterations in microparticle-mediated hemostasis and inflammation.

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