It is the first time blood vessels created entirely from a patient’s own tissues have been used for this purpose, the researchers report in the current issue of The New England Journal of Medicine.

Cytograft Tissue Engineering of Novato, Calif., made the vessels, in a process that takes six to nine months. Because they are derived from patients’ own cells, they eliminate the need for antirejection drugs. And because they are devoid of any synthetic materials or a scaffolding, they avoid complications from inflammatory reactions.
Doctors in Argentina have performed the first human tests of the vessels on six patients, the team reported. Two additional implants have been performed since the report was submitted, said Dr. Todd N. McAllister of Cytograft.
Cytograft says the vessels hold promise for patients with damaged blood vessels from diabetes, arteriosclerosis, birth defects and other problems.

“This technique has a big potential in the vascular surgical field,” said Dr. Toshiharu Shinoka, who directs pediatric cardiovascular surgery at Yale and who plans to conduct studies with Cytograft on the new vessel. He called the technique an advance over one he used in operations on children in Japan, in which vessels were grown from cells on a scaffold that then degraded and was absorbed into the body.

The patients were all receiving chronic kidney dialysis, which cleanses wastes from the blood. As is standard for such treatment, doctors had surgically cut an artery and a vein in the forearm and joined them in a link known as a shunt, which provides access for the repeated needle punctures needed to connect a patient to a dialysis machine. Such shunts can last up to 15 years. But when clots and infections develop in the shunts to reduce or stop blood flow, new ones must be created.

Dr. Sergio A. Garrido, a vascular surgeon in Buenos Aires, said he implanted the Cytograft vessels in the forearm or upper arm under general anaesthesia, in a different area from the malfunctioning shunt. The procedure took 60 to 90 minutes. Through surgical gloves, the Cytograft vessel, 5 ½ to 11 ¾ inches long, felt a little more delicate than a regular vein, he said.

The skin biopsy takes about 15 minutes. Under local anaesthesia, a doctor removes a piece of skin, including a strip of vein about an inch long, from the back of the hand or inner wrist. Then technicians use enzymes to extract fibroblast cells from the skin and endothelial cells from the inner lining of the vein. The cells are grown by the millions as sheets in a laboratory. The fibroblasts provide a mechanical backbone for the sheets that are peeled and rolled into a tube.

Although the vessel resembles a vein under the microscope, it has the mechanical strength of an artery, Dr. McAllister said. The technique allows the body over time to remodel the cells from a vein into a vessel with the elasticity of an artery.