Adventitial Gene Transfer of Recombinant Endothelial Nitric Oxide Synthase to Rabbit Carotid Arteries Alters Vascular Reactivity

Abstract

We conclude that eNOS gene transfer to the adventitia alters vascular reactivity, as demonstrated by diminished contractile responses to phenylephrine and enhanced relaxations to calcium ionophore. This may represent a therapeutic strategy for vascular diseases characterized by decreased bioavailability of NO.

A direct mechanical method for accurate and efficient adenoviral vector delivery to tissues

“…19,20 Ex vivo experiments were carried out using arteries harvested from mongrel dogs. Canine carotid artery (5 mm outer diameter (OD)) was chosen for its robust size and ease of surgical access.…”

“…Ex vivo delivery of this vector has been carried out by immersion of arterial tissue in a chamber containing vector-solution, 3,5,11 while in vivo delivery has been carried out through the lumen of an artery, that is, by direct injection, or via its outer ''adventitial'' layer, that is, perivascularly. 2,4,7,8,10,13,[19][20][21] A number of groups have demonstrated the ability of perivascular (adventitial) gene delivery to favorably and profoundly modify vasomotor function in a variety of cardiovascular models [3][4][5][11][12][13]19,20,22 and this approach, which has been reported to minimize the proinflammatory effects of adenoviral vectors, 10 can be used as an effective adjunct to the deployment of intravascular gene delivery stents and catheters. In vivo, current vascular gene delivery techniques have limited ability to produce specific targeting and selective localization of vector in a desired arterial territory or individual vessel.…”

“…While this method was shown to be helpful in similar in vivo gene transfer studies carried out in a largeanimal model, 4,13 vector delivery was still relatively indirect and nonfocal. In a more direct method of mechanical delivery to the carotid artery described by Kullo et al, 19 sequestration of vector around the vascular adventitia was carried out to facilitate more focal gene transfer. However, in addition to requiring carotid artery sheath incision and insertion of a perivascular catheter for vector delivery, this method, like others, requires prolonged vector incubation times, typically 30 min to 2-3 h. 3,5,9,11,23,30,31 In the case of nonreaspirated adventitial injection of vector, the transduction time is ''indefinite'', that is, till the time of sacrifice of the animal.…”

“…However, in addition to requiring carotid artery sheath incision and insertion of a perivascular catheter for vector delivery, this method, like others, requires prolonged vector incubation times, typically 30 min to 2-3 h. 3,5,9,11,23,30,31 In the case of nonreaspirated adventitial injection of vector, the transduction time is ''indefinite'', that is, till the time of sacrifice of the animal. 10,19 Several groups have used viral titers of 10 9 -10 10 plaque forming units (PFU) per ''target'' (ie, vessel segment of vascular territory within a living host) to facilitate effective expression of recombinant proteins in the vessel wall. [2][3][4][5][9][10][11][12][13]19,20,23,32 To explore the possibility of effective mechanical delivery of adenoviral vector to tissues, we postulated that a small paintbrush could be used to rapidly, efficiently, and accurately apply an adenoviral vector directly to a desired tissue target in vivo.…”

“…10,19 Several groups have used viral titers of 10 9 -10 10 plaque forming units (PFU) per ''target'' (ie, vessel segment of vascular territory within a living host) to facilitate effective expression of recombinant proteins in the vessel wall. [2][3][4][5][9][10][11][12][13]19,20,23,32 To explore the possibility of effective mechanical delivery of adenoviral vector to tissues, we postulated that a small paintbrush could be used to rapidly, efficiently, and accurately apply an adenoviral vector directly to a desired tissue target in vivo. This work suggests that our mechanical vector delivery method facilitates enhanced concentration and localization of vector at the tissue surface to which it was directly applied, enabling reduction of vector incubation time and titer in vivo.…”