Novel Stem Cell Technique Enhances Vascular Graft Development

A cutting-edge technique for attaching stem cell-derived arterial cells to synthetic grafts could revolutionise small-vessel bypass surgery.

• Researchers developed a stem cell-based coating method for synthetic grafts.
• Mussel-inspired proteins were key to overcoming attachment challenges.
• Successful primate trials suggest significant potential for clinical use.

Scientists at the Wisconsin National Primate Research Center (WNPRC) and the Morgridge Institute for Research at the University of Wisconsin–Madison have developed an innovative technique to engineer small-diameter vascular grafts using stem cell technology. Detailed in the journal Cell Reports Medicine, this method addresses a major hurdle in vascular surgery: effectively lining synthetic graft materials with human arterial endothelial cells (AECs).

Mussel-Inspired Bioadhesion

The team faced significant challenges with expanded polytetrafluoroethylene (ePTFE), a durable but hydrophobic material commonly used for vascular grafts. Its water-repellent nature prevents effective attachment of cells, a critical step in creating viable grafts.

Inspired by mussel adhesive proteins, researchers employed a dual-layer coating comprising dopamine and vitronectin. Dopamine, a chemical component derived from mussel proteins, provided the initial adhesive layer, while vitronectin, a cell-adhesion protein, facilitated the attachment of stem cell-derived AECs. This innovative coating overcame the hydrophobic limitations of ePTFE, ensuring robust and uniform cell adhesion under physiological blood-flow conditions.

Preclinical Validation and Future Prospects

The newly developed grafts were rigorously evaluated in Rhesus macaques, chosen for their close biological resemblance to humans. Researchers compared grafts lined with standard AECs expressing major histocompatibility complex (MHC) proteins, grafts without MHC proteins, and uncoated grafts.

Grafts featuring MHC-expressing cells demonstrated successful integration and stable function for six months, markedly outperforming those lacking MHC proteins, many of which failed due to immune rejection mediated by natural killer cells. Ultrasound monitoring showed effective graft integration and host cell repopulation, confirming the method’s viability.

Igor Slukvin, senior co-author and professor at UW–Madison, highlighted the significance of this approach, stating it represents “an important step in advancing stem cell technologies for bioengineering vascular grafts for cardiac vessel repair and their clinical translation.”

Samuel Poore, chair of plastic surgery at UW–Madison and co-author, noted this technique’s potential to greatly expand surgical possibilities, saying it could “limit morbidity of operations, and give options for surgery that currently don’t exist.”

This stem cell-driven bioengineering technique promises significant improvements for clinical trials and could become an essential tool for surgeons dealing with vascular, cardiac, and reconstructive procedures