"Off the Shelf” Vascular Grafts

Artificial blood vessels from muscle-derived stem cells (MDSCs) and a biodegradable polymer that exhibit extensive remodeling and remain free of blockages may soon be available, claims a new study.

Researchers from the University of Pittsburgh School of Medicine (UPMC; PA, USA) developed the vascular grafts by spraying MDSCs inside a biodegradable porous, tubular polyester urethane scaffold using a rotational vacuum, bulk-seeding device. After culturing the vascular constructs for seven days, the investigators then implanted them in the abdominal aortas of rats eight weeks before performing tests to determine how well the grafts had performed.

The results showed that the cell-seeded constructs showed a significantly higher blockage-free rate than unseeded controls (55% vs 0%). In addition, at eight weeks, there was an extensive remodeling of the MDSC-seeded polymer by surrounding tissue, exhibiting tissue formation that is consistent with a mature artery. The results of the study were presented at the Tissue Engineering and Regenerative Medicine International Society (TERMIS) North America chapter meeting held during June 2007 in Toronto (Canada).

"The advantage of our approach is that the graft could utilize the patient's own stem cells and be ready for implantation almost immediately or, at most, after a relatively short culture period,” said lead author David A. Vorp, Ph.D., an associate professor of surgery and bioengineering. "This suggests that we could make these available ‘off-the-shelf,' which is an essential element for clinical translation.”

The saphenous vein taken from a patient's own leg is the most commonly used graft for coronary artery bypass grafting, even though a significant percentage of vein grafts eventually fail. Arterial grafts are the preferred conduits because they are less prone to becoming obstructed. However, they are in very limited supply, as many patients require multiple grafts.


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