Overexpression of transforming growth factor-beta1 stabilizes already-formed aortic aneurysms: a first approach to induction of functional healing by endovascular gene therapy.
BACKGROUND
The cell response to transforming growth factor-beta1 (TGF-beta1), a multipotent cytokine with healing potential, varies according to tissue context. We have evaluated the ability of TGF-beta1 overexpression by endovascular gene therapy to stabilize abdominal aortic aneurysms (AAAs) already injured by inflammation and proteolysis.


RESULTS
Active TGF-beta1 overexpression was obtained in already-developed experimental AAAs in rats after endovascular delivery of an adenoviral construct encoding for a mutated form of active simian TGF-beta1 and in an explant model using human atherosclerotic AAA fragments incubated with recombinant active TGF-beta1. Transient exogenous TGF-beta1 overexpression by endovascular gene delivery was followed by induction of endogenous rat TGF-beta1. Overexpression of active TGF-beta1 in experimental AAAs was associated with diameter stabilization, preservation of medial elastin, decreased infiltration of monocyte-macrophages and T lymphocytes, and a decrease in matrix metalloproteinase-2 and -9, which was also observed in the explant model, in both thrombus and wall. In parallel with downregulation of the destructive process, active TGF-beta1 overexpression triggered endoluminal reconstruction, replacing the thrombus by a vascular smooth muscle cell-, collagen-, and elastin-rich intima.


CONCLUSIONS
Local TGF-beta1 self-induction after transient exogenous overexpression reprograms dilated aortas altered by inflammation and proteolysis and restores their ability to withstand arterial pressure without further dilation. This first demonstration of stabilization of expanding AAAs by delivery of a single multipotent self-promoting gene supports the view that endovascular gene therapy should be considered for treatment of aneurysms.
Dai
Jianping
J
CNRS UMR 7054, Centre de Recherches Chirurgicales, Université Paris XII, UFR de Médecine, Créteil, France.
Losy
Franck
F
Guinault
Anne-Marie
AM
Pages
Carine
C
Anegon
Ignacio
I
Desgranges
Pascal
P
Becquemin
Jean-Pierre
JP
Allaire
Eric
E
D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000235:genetics / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D001483:Base Sequence; D017931:DNA Primers; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000637:transplantation*; D018093:Gelatinases / Q000378:metabolism; D006168:Guinea Pigs; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D053773:Transforming Growth Factor beta1; D018183:Transplantation Chimera; D014183:Transplantation, Heterologous
D017931:DNA Primers; D011994:Recombinant Proteins; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat; D019715:Tissue Inhibitor of Metalloproteinase-1; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D018093:Gelatinases