Microparticles from ischemic muscle promotes postnatal vasculogenesis.
BACKGROUND
We hypothesized that microparticles (MPs) released after ischemia are endogenous signals leading to postischemic vasculogenesis.


RESULTS
MPs from mice ischemic hind-limb muscle were detected by electron microscopy 48 hours after unilateral femoral artery ligation as vesicles of 0.1- to 1-microm diameter. After isolation by sequential centrifugation, flow cytometry analyses showed that the annexin V(+) MP concentration was 3.5-fold higher in ischemic calves than control muscles (1392+/-406 versus 394+/-180 annexin V(+) MPs per 1 mg; P<0.001) and came mainly from endothelial cells (71% of MPs are CD(144+)). MPs isolated from ischemic muscles induced more potent in vitro bone marrow-mononuclear cell (BM-MNC) differentiation into cells with endothelial phenotype than those isolated from control muscles. MPs isolated from atherosclerotic plaques were ineffective, whereas those isolated from apoptotic or interleukin-1beta-activated endothelial cells also promoted BM-MNC differentiation. Interestingly, MPs from ischemic muscles produced more reactive oxygen species and expressed significantly higher levels of NADPH oxidase p47 (6-fold; P<0.05) and p67 subunits (16-fold; P<0.001) than controls, whereas gp91 subunit expression was unchanged. BM-MNC differentiation was reduced by 2-fold with MPs isolated from gp91-deficient animals compared with wild-type mice (P<0.05). MP effects on postischemic revascularization were then examined in an ischemic hind-limb model. MPs isolated from ischemic muscles were injected into ischemic legs in parallel with venous injection of BM-MNCs. MPs increased the proangiogenic effect of BM-MNC transplantation, and this effect was blunted by gp91 deficiency. In parallel, BM-MNC proangiogenic potential also was reduced in ABCA1 knockout mice with impaired vesiculation.


CONCLUSIONS
MPs produced during tissue ischemia stimulate progenitor cell differentiation and subsequently promote postnatal neovascularization.
Leroyer
Aurelie S
AS
Paris Cardiovascular Research Center, INSERM U, Hôpital Européen Georges Pompidou, Université Paris-Descartes, France.
Ebrahimian
Téni G
TG
Cochain
Clément
C
Récalde
Alice
A
Blanc-Brude
Olivier
O
Mees
Barend
B
Vilar
José
J
Tedgui
Alain
A
Levy
Bernard I
BI
Chimini
Giovanna
G
Boulanger
Chantal M
CM
Silvestre
Jean-Sébastien
JS
D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology; D000818:Animals; D017304:Annexin A5 / Q000494:pharmacology; D002454:Cell Differentiation; D015687:Cell Hypoxia; D055252:Cell-Derived Microparticles / Q000502:physiology* / Q000637:transplantation; D042783:Endothelial Cells / Q000473:pathology; D004730:Endothelium, Vascular / Q000473:pathology; D004790:Enzyme Induction; D005263:Femoral Artery; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007511:Ischemia / Q000097:blood* / Q000503:physiopathology / Q000601:surgery; D008026:Ligation; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000098:blood supply*; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000096:biosynthesis / Q000235:genetics; D018919:Neovascularization, Physiologic / Q000502:physiology*; D017382:Reactive Oxygen Species
C577836:ABCA1 protein, human; D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D017304:Annexin A5; D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1