Algae molecules to improve bypass surgery outcomes

Photo of the synthetic grafts made by the researchers. Photo credit: University of Waterloo

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 cardiac bypass surgeries.

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 – that are prone to clots that can develop into full-blown occlusions.

“There is a critical need to develop synthetic vascular graft materials that increase the rate of long-term function,” said Dr. Evelyn Yim, a chemical engineering professor and university research director who is leading the project.

The researchers added a material called fucoidan, made from seaweed, to modify synthetic blood vessels. Fucoidan is similar in structure to heparin, a drug used as an anticoagulant.

When Fucoidan is applied using a nanotechnology technique known as micropatterning, it promotes the growth of vascular cells around the inner surface of the graft, greatly reducing the chance of blood clots forming.

Potential patient benefits include fewer complications, a better quality of life, and a reduced risk of recurrence of blockages that require additional drug treatment or surgery.

“A functional, commercially available, small diameter vascular graft will help save lives,” said Yim, director of the Regenerative Nanomedicine Lab in Waterloo. “The important thing is that they last much longer and allow the blood to flow freely.”

Bypass surgery is performed to restore blood flow to areas of the heart when vessels are blocked. Vessels harvested from the patient are the gold standard for grafts, but limited availability often necessitates the use of artificial vessels.

In addition to heart bypass surgery, transplants 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 possibility of clots that can develop into complete blockages or cause inflammation that restricts blood flow.

Yim has successfully tested the new technique in small animals using fucoidan and micropatterns and plans to expand it to large animal trials before moving to 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.

A review of the work, Fucoidan and topographical modification enhanced in situ endothelialization on acellular synthetic vascular grafts appears in the journal Bioactive Materials.

More information:
Yuan Yao et al., Fucoidan and topography modification enhanced in situ endothelialization on acellular synthetic vascular grafts, Bioactive Materials (2022). DOI: 10.1016/j.bioactmat.2022.10.011

Provided by the University of Waterloo

Citation: Algal Molecules to Improve Bypass Surgery Outcomes (2022 December 5), retrieved December 5, 2022 from

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