HIV-based vectors and angiogenesis following rabbit hindlimb ischemia.
BACKGROUND
Numerous medical and surgical options exist for the treatment of vessel ischemia, which some patients fail or cannot tolerate. These investigations were designed to determine the effects of lentiviral-delivered vascular endothelial-derived growth factor (VEGF) and angiopoietin-2 (Ang-2) on collateralization in a rabbit model of hindlimb ischemia.


METHODS
Self-inactivating human immunodeficiency virus (HIV)-based vectors were constructed encoding VEGF or Ang-2, co-transfected with vesicular stomatitis virus glycoprotein (VSV G) into 293T cells, and vector supernatants (1 x 10(8) IU/ml after concentration) were harvested. New Zealand white rabbits had ligation of either the right or left external iliac artery and excision of the ipsilateral femoral artery. Ten days later, empty, VEGF, or VEGF+Ang-2 vector supernatant was injected intramuscularly (IM) into the ipsilateral thigh. Ankle systolic blood pressure (SBP) ratios were recorded and venous blood samples collected on postoperative days (POD) 10, 25, and 40. On POD 40, run-off angiography was performed to measure vessel collateralization. Capillary density was determined by thin sectioning of muscle.


RESULTS
A significant increase was noted in SBP in the VEGF-treated animals over time. Capillary density was not elevated despite significantly increased large vessel collateralization in rabbits receiving VEGF, which was counteracted by Ang-2. Antibodies against vector components were detected in exposed serum.


CONCLUSIONS
Arterial collateralization and SBP increased significantly following VEGF vector administration, which was reversed by the Ang-2 vector. Development of antibody against VSV G can limit repeated injections of vector. Future experiments will involve the addition of other pro-angiogenic factors, repeated vector administration, and alternative routes of vector delivery.
Conklin
Lori D
LD
The Michael E. DeBakey Department of Surgery, Division of Cardiothoracic Surgery, Baylor College of Medicine, Houston, Texas 77030, USA.
McAninch
Robin E
RE
Schulz
Daryl
D
Kaluza
Grzegorz L
GL
LeMaire
Scott A
SA
Coselli
Joseph S
JS
Raizner
Albert E
AE
Sutton
Richard E
RE
D042702:Angiopoietin-2 / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D015316:Genetic Therapy; D005822:Genetic Vectors; D006678:HIV / Q000235:genetics*; D006614:Hindlimb / Q000098:blood supply*; D007511:Ischemia / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000276:immunology; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic; D011817:Rabbits; D013599:Systole; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000276:immunology
D042702:Angiopoietin-2; C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D042461:Vascular Endothelial Growth Factor A; D014759:Viral Envelope Proteins