Local delivery of an antiproliferative drug with use of hydrogel-coated angioplasty balloons

In Vivo Human MCP-1 Transfection in Porcine Arteries by Intravascular Electroporation

PURPOSE

The purpose of this study was to develop a nonviral gene transfer method for therapeutic delivery of the human monocyte chemoattractant protein-1 (MCP-1) in patients with peripheral artery disease, using local catheter-mediated electrotransfer of naked plasmid DNA into arteries.

METHODS

Arterial walls of the A. profunda femoris of pigs were transfected either with a human MCP-1 or with a firefly luciferase-encoding DNA construct. The efficacy of electrotransfer of DNA was analyzed after 2 days by quantitative polymerase chain reaction (PCR) or luciferase activity measurements. To optimize MCP-1 gene transfer conditions, a voltage range of 60-150 V was applied as a train of six square pulses of 20 ms each at 1 Hz and was combined with a dose of 150 microg DNA. Subsequently, the optimized voltage was used to test a dose range of 80-300 microg DNA.

RESULTS

The voltage optimum for arterial transfection was observed at 80 volts. Using this setting, the dose application of 300 microg MCP-1 plasmid DNA (the maximal dose tested) demonstrated the highest MCP-1 expression signal. The electric pulses and the transfer and expression of human MCP-1 per se did not induce endogenous porcine MCP-1 expression in treated arteries. Interestingly, angioplastic predilation of the artery before gene transfer, which had originally been postulated to enhance transfection by improving access of the plasmid to subendothelial cell layers, resulted in an attenuated transfection efficacy.

CONCLUSIONS

The present study demonstrates that transluminal catheter-based electroporation provides an efficient technology for nonviral intravascular gene transfer by just applying unformulated DNA.

Controlled release of platelet-derived growth factor-BB from chondroitin sulfate-chitosan sponge for guided bone regeneration

Platelet-derived growth factor-BB (PDGF-BB) releasing porous chondroitin-4-sulfate (CS)-chitosan sponge was designed with an aim of controlling growth factor delivery in order to improve bone formation. Porous CS-chitosan sponge was fabricated by freeze drying and crosslinking aqueous CS-chitosan solution. PDGF-BB was incorporated into the CS-chitosan sponge by soaking CS-chitosan sponge into the PDGF-BB solution. CS-chitosan sponge retained a porous structure with a 150-200-microm pore diameter that was suitable for cellular migration and osteoid ingrowth. Release rate of PDGF-BB could be controlled by varying the composition of CS in the sponge or initial loading content of PDGF-BB. CS-chitosan sponge induced increased osteoblast migration and proliferation as compared with chitosan sponge alone. Furthermore, the release of PDGF-BB from CS-chitosan sponge significantly enhanced osteoblast proliferation. These results suggest that PDGF-BB-releasing CS-chitosan sponge may be beneficial to enhance bone cell adaptation and regenerative potential when applied in wound sites.

Local delivery of nadroparin via hydrogel-coated angioplasty balloon: effect on platelet deposition and smooth muscle cell proliferation--an experimental study

PURPOSE

To assess the feasibility of intravascular delivery of nadroparin, a low-molecular-weight heparin, via hydrogel-coated angioplasty balloons, and the effects of nadroparin delivered in this manner on platelet deposition and smooth muscle cell (SMC) proliferation.

MATERIALS AND METHODS

Tritiated nadroparin was used to determine the nadroparin-carrying capacity of the hydrogel-coating, kinetics of release from the balloons, and, in four pigs, delivery of the nadroparin to the iliac arterial wall. Platelet deposition in nadroparin-treated iliac arteries versus contralateral iliac arteries dilated with saline-loaded, hydrogel-coated balloons was quantified in seven pigs using 111Indium-labeled platelets. Smooth muscle cell proliferation in nadroparin and saline-treated iliac arteries in 10 pigs was evaluated 7 days after angioplasty with use of proliferating cell nuclear antigen.

RESULTS

Approximately 98 international units of nadroparin were delivered by the hydrogel-coated balloon, the majority to the angioplasty site and distal vessel. There was a trend toward decreased platelet deposition in nadroparin-treated arteries, but statistical significance was not achieved (P = .1563). Medial SMC proliferation was decreased in the nadroparin-treated arteries in nine of 10 pigs (P = .0137).

CONCLUSIONS

Hydrogel-coated balloons may be used to deliver nadroparin to the arterial wall, with measurable levels of the drug delivered to the site of angioplasty, and with resultant decrease in SMC proliferation.

Polypeptide growth factors: targeted delivery systems

Growth factors are becoming extremely valuable tools in our attempts to understand the mechanisms that modulate cellular activities. Their targeting to appropriate cells and maintaining adequate pharmacological levels becomes essential, particularly in view of the different effects that these compounds have on various cells and the dose dependence of their response. Within this context, this review focuses primarily on the delivery of growth factors involved in the processes of wound healing and tissue repair.

Local delivery of heparin with balloon angioplasty: results of a prospective randomized trial

PURPOSE

To evaluate the effectiveness of local delivery of heparin via hydrogel-coated balloons in the treatment of vascular stenoses associated with hemodialysis access.

MATERIALS AND METHODS

This was a randomized, prospective trial comparing treatment with hydrogel-coated balloon catheters delivered with heparin coating (n = 33) and without (n = 26). All patients were undergoing hemodialysis, and all stenoses involved the venous anastomosis of a dialysis graft or a native vein. The heparin-treated balloons were soaked in concentrated heparin and delivered in a protected manner to help prevent washout of heparin.

RESULTS

The mean primary patencies were 143 days with heparin treatment and 214 days without heparin (P = .174). The mean assisted primary patencies were 165 days with heparin and 194 days without (P = .315). The mean secondary patencies were 351 days with heparin and 384 without (P = .81).

CONCLUSION

In this population with this technique, the treatment outcome of venous outflow stenosis in patients with dialysis grafts is not improved with local delivery of heparin.