Patients with heart disease commonly receive metal stents in partially blocked blood vessels to improve blood flow, both by widening the vessels and delivering drugs. However, many stents fail over time as smooth muscle cells accumulate excessively on their surfaces and create new blockages. One goal of cell therapy is to introduce new endothelial cells to recoat stents with a smooth surface.
Furthermore, Levy adds, while drug-releasing stents currently provide benefits in treating diseased coronary arteries, they have proved far less effective in treating peripheral vascular disease, such as that occurring in patients with diabetes. In such cases, severe problems in blood circulation may force doctors to amputate a leg. In upcoming animal studies, Levys team will use their delivery approach to deliver magnetic nanoparticles to peripheral arteries.
Future studies, Levy added, also will use cells derived from the animal itself, to avoid potential rejection problems that may occur with unmatched cells. The current study used unmatched cells, delivering bovine cells to rat arteries, but only over a 48-hour period, too brief for rejection to occur.
The current study builds on research published earlier this year by Levy and collaborators, in which they used magnetic fields and nanoparticles to deliver DNA to arterial muscle cells in culture. That research focused on a delivery system for gene therapy, while the current study represents cell therapy. Levy suggests future applications may combine both therapies, using endothelial cells to deliver beneficial genes to damaged arteries.
The delivery system, says Levy, might also be applied to other sites where physicians implant steel stents to deliver medication, such as the esophagus, bile ducts and lungs. Another potential use might be
|Contact: John Ascenzi|
Children's Hospital of Philadelphia