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Biotech Firm Grows Blood Vessels in Lab
Starting with bits of skin, scientists have produced new blood vessels in a laboratory and successfully implanted them into two patients, a medical first. Previously, vessels grown in a lab had failed to hold together without the support of a synthetic backing. Unfortunately, backing materials such as plastic aren't flexible enough to handle the variable pressures of blood flow and trigger inflammation, which encourages blood clots.
Researchers at Cytograft Tissue Engineering in Novato, Calif., have created vessels from a patient's own cells, an approach that avoids inflammation, clot formation, and immune rejection. Surgeons in Argentina installed the engineered vessels in place of artificial shunts in the arms of two kidney-dialysis patients. 6 months post-operative analysis found the new vessels working well, commented the Cytograft scientists. Findings were announced at the last American Heart Association meeting in Dallas.
The team now plans to test the vessels in more kidney patients and eventually in heart patients. The Cytograft researchers hope to get the procedure approved for coronary-bypass surgery in about 5 years.
The scientists start by taking immature cells called fibroblasts from a patient's skin and growing sheets of the cells in lab dishes. Each sheet is about the size of a postcard. They roll each sheet around a tube the diameter of a narrow drinking straw. Finally, they withdraw the tube and seed each nascent vessel with cells taken from the lining of one of the patient's blood vessels.
The group is testing the vessels in dialysis patients first because arm surgery poses fewer risks than a heart-bypass operation. “The two dialysis patients using the tissue-engineered vessels have been free of complications 6 months since surgery”, says biomedical engineer and head of Cytograft Todd McAllister.
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