Bioengineered Blood Vessels Improve Long-Term Dialysis Experience
Dialysis is a process that assumes some of the tasks that the kidneys would do when a patients own are unable to perform them. The process works by a doctor or qualified technician connecting a patient to the dialysis machine usually located in a hospital or health center.
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The process begins when a needle is inserted into a patent is arm or leg to give access to their blood vessel, their blood is then carried through the dialysis machine, and a special filter called an artificial kidney, or a dialyzer.
Live saving procedure
The dialyzer cleans a patient's blood from any impurities that their kidneys can’t do on their own. Patients who require regular dialysis may only have 10-15% of their kidney function left.
Without dialysis, they would likely die from toxic build up. Many patients may require regular dialysis for years to maintain their health.
The regular needle sticks in the patient's arms or legs may damage their blood vessels. In this case, a synthetic graft is needed.
Synthetic grafts bring complications
However, these grafts can often get infected or cause other complications. New research from a collaborative research team from Duke University, Yale University, and the tissue engineering company Humacyte Have developed bioengineered grafts that in initial testing perform just as well as the synthetic grafts.
The research team has tested their bioengineered vessel on 60 patients with kidney failure who required dialysis. The new vessels can be produced on demand rather than using an individual's own cells.
“The bioengineered blood vessel represents a critical step in tissue engineering,” said Jeffrey Lawson, M.D., Ph.D., professor of surgery and pathology at Duke and chief medical officer of Humacyte.
“Because these vessels contain no living cells, patients have access to off-the-shelf engineered grafts that can be used without any waiting period associated with tailor-made products.”
Bioengineered cells adopted by the body
The vessels were created from isolated vascular cells from human donors which were then grown in tissue culture. The cells were then placed on biodegradable scaffolding shaped like a blood vessel. As the tissue grew around this shape it was stretched to get the physical attributes of a real blood vessel and bathed in nutrients to stimulate growth.
“After that process, which takes eight weeks, the scaffold degrades and what we have left is engineered tissue that we have grown from scratch,” Niklason said.
Finally, the vessels are washed to remove the cells, these “de-cellularized” vessels then have none of the components that would cause tissue rejection.
The test subjects have had their bioengineered vessels for over a year now and show no signs of rejection or degrading. The study did record some instances of adverse clotting.
This is not uncommon in both natural and synthetic vessels. The bioengineered vessels did outperform the synthetic vessels in terms of durability. Interestingly the bioengineered ‘cell-free’ vessels actually became populated with the patient's own cells over time.
“The fact that an implanted acellular tube becomes a living human tissue has implications for regenerative medicine in a very profound way,” Lawson said.