Chronic venous insufficiency is associated with elevated level of circulating microparticles.
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.


OBJECTIVE
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.


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 circulating EMPs and PMPs; (ii) a structural modification 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.
Georgescu
A
A
Institute of Cellular Biology and Pathology, 'Nicolae Simionescu', Bucharest, Romania. adriana.georgescu@icbp.ro
Alexandru
N
N
Popov
D
D
Amuzescu
M
M
Andrei
E
E
Zamfir
C
C
Maniu
H
H
Badila
A
A
D000109:Acetylcholine / Q000494:pharmacology; D017209:Apoptosis; D001792:Blood Platelets / Q000166:cytology / Q000473:pathology; D004727:Endothelium / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron / Q000379:methods; D008863:Microspheres; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D009638:Norepinephrine / Q000494:pharmacology; D019007:P-Selectin / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013925:Thromboplastin / Q000378:metabolism; D014689:Venous Insufficiency / Q000097:blood*
D019007:P-Selectin; D012701:Serotonin; D011189:Potassium Chloride; D013925:Thromboplastin; D000109:Acetylcholine; D009638:Norepinephrine