Lab-Grown Blood Vessels Seem to Help Dialysis
MONDAY, June 27 (HealthDay News) -- In early research, blood
vessels originating from a donor's skin cells and grown in a
laboratory have been successfully implanted in three dialysis
These engineered grafts have functioned well for about 8 months,
say researchers reporting Monday at a special online conference
sponsored by the American Heart Association.
The three patients -- all of whom lived in Poland and were on
dialysis for end-stage kidney disease -- received the new vessels
to allow better access for dialysis. But the hope is that these
types of bioengineered, "off-the-shelf" tissues can someday be used
as replacement arteries throughout the body, including heart
"The grafts available now perform quite poorly," said lead researcher Todd N. McAllister, co-founder and chief executive officer of Cytograft Tissue Engineering Inc., the Novato, Calif.-based maker of the grafts and the funder of the study.
Currently, these types of vessels are typically made of
synthetic material or they are grafts of the patient's own veins,
McAllister explained. In either case, he said, the rate of failure
and the need for redoing the procedures remains high.
In the new study, donor skin cells were used to grow the blood
vessels. The vessels were made from sheets of cultured skin cells,
rolled around a temporary support structure in the lab. Upon
implantation the vessels typically measured about a foot long and a
fifth of an inch in diameter.
After implantation, the vessels were used as "shunts" between
arteries and veins in the arm to gave the patient access to
"To date all the grafts are patent [functioning well]," McAllister said. "Perhaps most interestingly, we have seen no clinical manifestations of an immune response," he said.
In fact, over eight months after implantation, none of the
patients show any signs of rejecting the graft. The grafts have
also been able to handle the high pressures and frequent needle
punctures needed to deliver dialysis, the researchers found.
In earlier work, McAllister's group showed that vessels grown
using a patient's own skin cells reduced the rate of complications
typically seen with shunts by more than two-fold over 3 years.
However, the advantage of these new vessels, grown from donor
cells, is that it won't take six months to grow the tissue.
This off-the-shelf approach should make the technology available
for widespread use, McAllister added. He believes that, someday,
these types of blood vessels might replace the use of a patient's
own vessels for bypass surgery.
However, McAllister stressed that a phase 3 trial on the use of
the grafts is only now getting underway, so it will be several
years before these grafts could be clinically available.
And what about the treatment's cost? McAllister said that
producing the tissue is very expensive. Speaking with
Bloomberg News, he estimated that each graft might cost between $6,000 and $10,000.
Commenting on the study, Dr. Gregg C. Fonarow, professor of
cardiology at the University of California, Los Angeles, agreed
that "there has been great interest in developing safer and more
reliable vascular access for patients receiving dialysis."
Access for dialysis, bleeding and infection are major causes of
death for patients in dialysis, he said. "A high percentage of
hospitalizations and health care expenditures in dialysis patients
are due to vascular access complications," Fonarow said.
But he cautioned that these are still early days for this
"This approach appears very promising, but will need to be prospectively evaluated in much larger longer term studies to determine the full potential of tissue engineered vascular grafts for this and other uses," he said.
For more information on kidney failure, visit the
U.S. National Library of Medicine.
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