Researchers are using a natural material derived from seaweed to promote vascular cell growth, prevent blood clots and improve the performance of synthetic vascular grafts used in heart bypass surgery.
The new approach, developed and tested at the University of Waterloo, is particularly important in cases involving small artificial blood vessels – those less than six millimeters in diameter – which are prone to clots that can develop into complete blockages.
“There is a critical need to develop synthetic vascular graft materials that will increase the rate of long-term function,” said Dr. Evelyn Yim, professor of chemical engineering and University Research Chair who leads the project.
The researchers added a material called fucoidan, made from algae, to modify the synthetic blood vessels. Fucoidan is similar in structure to heparin, a drug used as a blood thinner.
When applied with a nanotechnology technique known as micropatterning, fucoidan promotes the growth of vascular cells around the inner surface of the graft, significantly reducing the chances of clot formation.
For patients, the potential benefits include fewer complications, better quality of life and less risk of recurrence of blockages requiring additional drug treatment or surgery.
“A functional, ready-to-use, small-diameter vascular graft will help save lives,” said Yim, director of the Regenerative Nanomedicine Lab at Waterloo. “What’s important is that they will last much longer and allow blood to flow freely.”
Bypass surgery is performed to restore blood flow to areas of the heart where the vessels are blocked. Vessels taken from the patient are the gold standard for transplants, but limited availability often necessitates the use of artificial vessels.
In addition to heart bypass surgery, grafts are used in medical procedures to treat vascular disease and restore blood flow to vital organs and tissues, including the brain and legs.
When synthetic graft material does not allow vascular cells to grow inside an artery or vessel, there is a high risk of clots, which can develop into complete blockages or cause inflammation that restricts blood flow.
Yim has successfully tested the new technique using fucoidan and micropatterning on small animals and plans to expand to large animal testing before moving into clinical trials.
Several researchers from the Department of Chemical Engineering at Waterloo and the Department of Biomedical Engineering at Oregon Health and Science University collaborated on this project.
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