Researchers from North Carolina State (NC State) University have developed an exosome-coated stent with a “smart-release” trigger that could both prevent reopened blood vessels from narrowing and deliver regenerative stem cell-derived therapy to blood-starved, or ischemic, tissue. Angioplasty--a procedure that opens blocked arteries--often involves placing a metal stent to reinforce arterial walls and prevent them from collapsing once the blockage is removed. However, the stent’s placement usually causes some injury to the blood vessel wall, which stimulates smooth muscle cells to proliferate and migrate to the site in an attempt to repair the injury. The result is restenosis: a re-narrowing of the blood vessel previously opened by angioplasty. “The inflammatory response that stents cause can decrease their benefit,” says Ke Cheng, PhD, corresponding author of the research. “Ideally, if we could stop smooth muscle cells from over-reacting and proliferating, but recruit endothelial cells to cover the stent, it would mitigate the inflammatory response and prevent restenosis.” Dr. Cheng is the Randall B. Terry Jr. Distinguished Professor in Regenerative Medicine at NC State and a Professor in the NC State/UNC-Chapel Hill Joint Department of Biomedical Engineering. There are drug-eluting stents currently in use coated with drugs that discourage cell proliferation, but these anti-proliferative drugs also delay stent coverage by endothelial cells--which are the cells healthcare providers want to coat the stent. To solve this problem, Dr. Cheng and his team developed a stent coating composed of exosomes derived from mesenchymal stem cells (MSCs). Exosomes are tiny nano-sized vesicles secreted by all cell types that have been studied.
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