Thin threads of human cellular material spun around a spindle make a sturdy rope.
These biological strands could be used to weave blood vessel patches and grafts to repair wounds for dialysis and heart disease patients. And patient’s body should readily accept these – making them faster and cheaper than other biological tissue replacements. Technology Review reports.
Previously, researchers have grown human skin cells in a culture flask under conditions that encourage cells to lay down a sheet of ‘extracellular matrix,’ the structural material that makes up connective tissue. These sheets were harvested and rolled into tubes to make replacement blood vessels – but the rolling process was expensive and took time because cells must be used to fuse the tube together like a seam.
San Francisco–based Cytograft Tissue Engineering shows how slicing these sheets into thin ribbons that can be spooled into threads makes it possible to use automated weaving and braiding machines to create 3D structures. These don’t require fusing and take days rather than months.
Current tissue engineering depends on synthetic scaffolds that are eventually degraded by the body. These new woven tissues stay in the body to become populated with cells. “We decided we were going to make strong tissues without any scaffolding,” says Cytograft’s Nicolas L’Heureux. “Once you get it in the body, your body doesn’t see it as foreign.”
While Cytograft’s implants are made using cultured cells, they don’t contain cells. That means the material can be harvested from donor cells unrelated to the person receiving the graft. Without any foreign cells to alert a patient’s immune system, the company could produce blood vessels ahead of time for use in any patient.
In preclinical animal trials, dogs had vessel grafts implanted in their legs. Those implants have remained intact for months. “Other materials get remodeled very aggressively,” L’Heureux says. “With our tissue, it is so innocuous the body does not see a danger.”
The technology was presented at the Experimental Biology 2012 annual meeting in San Diego last week.
Image of spools by MissMessie via Flickr