Autori: A. Georgescu, N. Alexandru, D. Popov, M. Amuzescu, E. Andrei, C. Zamfir, H. Maniu, A. Badila

Editorial: Journal of Thrombosis and Haemostasis, 7(9) , p.1566-1575, 2009.

Rezumat:

Background: Chronic venous insufficiency (CVI)
results when the veins in the legs no longer pump blood back to
the heart effectively. Microparticles (MPs) are small membrane
vesicles released by several circulating and vascular cells upon
activation or apoptosis. Objectives: The purpose of this study
was to assess the subpopulations of circulating endothelial
(EMPs) and platelet microparticles (PMPs) in CVI, and to
disclose their contribution in mediating dysfunction of human
peripheral venules. Patients and methods: Human peripheral
venules were explanted during leg surgery on patients with
CVI and on control subjects (C); concurrently, blood samples
were collected and circulating MPs isolated. The techniques
used were: flow cytometry, fluorescence and electron
microscopy, myograph technique and western-blotting
technique. Results: The results showed that compared with
controls, patients with CVI had: (i) a marked elevation of
circulatingEMPsand PMPs; (ii) a structuralmodification of the
venous wall consisting of activation of endothelial and smooth
muscle cells, an abundance of intermediary filaments and
synthesis of hyperplasic-multilayered basal lamina; (iii) a
significantly altered reactivity of the venous wall, closely
associated with EMPs and PMPs adherence; (iv) altered
contractile response to noradrenaline, acetylcholine, 5-hydroxytryptamine
and KCl, and an impeded relaxation in response to
sodium nitroprusside; and (iv) a substantially increased protein
expression of tissue factor (TF) and of P-Selectin both in the
venular vascular wall and on the surface of EMPs and
PMPs. Conclusions: The findings indicate that CVI is accompanied
by an enhanced release of EMPs and PMPs that
contribute to altered dysfunctional response of the venous
wall.

Cuvinte cheie: circulating microparticles, chronic venous insufficiency