Engineered Blood Vessels for Dialysis
First Ever Biologically Engineered Blood Vessels Show Promise for Several Illnesses
WebMD News Archive
Nov. 15, 2005 (Dallas) -- The first tissue-engineered blood vessels may provide new arteries and veins to thousands of patients with conditions from heart disease, kidney failure, or diabetes.
"This is the world's first implantation of a tissue-engineered blood vessel produced in the laboratory," says Todd McAllister, PhD, president and chief operating officer of Cytograft Tissue Engineering. "What is novel about this approach is we are able to build the vessel without any exogenous materials. The vessels are built with the patient's own cells."
The tissue-engineered blood vessels have either been grown or are in the process of being grown for six patients. Two have been implanted in kidney dialysis patients to offset damage in shunts placed in blood vessels of their arms used for dialysis. A third patient is expected to have the implant early next year.
The team is able to take two cell types -- skin and the inner lining of vessels -- from the patient's own body. The skin is grown into sheets, wrapped around a medical tube, and fused together, forming a vessel. Just before implantation into the patient, cells grown from the inner lining of the patient's own veins are cultured and grown within the engineered vessel.
But the largest benefit is that because the cells are the patient's own, there are no problems with rejection, McAllister explains. "There are no signs of failure or blood clots thus far in either patient receiving the implant."
Kidney Patients Get First Try
Initially the researchers plan to use the engineered vessels in patients with end-stage kidney disease undergoing regular dialysis. Because blood must be pumped through a shunt in the arm, often patients have failure of the shunts with damage from repeated use.
While synthetic vessels work well in larger vessels, the grafts don't work as well in smaller vessels in the arm, he says. "Roughly 25% of the grafts fail."
The second projected usage will be for lower limb salvage to prevent some of the 180,000 amputations that occur annually due to lack of blood flow in the legs, he says. Although stenting can be used in the thigh region, it is not as successful in the lower leg, he says.