A new study shows how dialysis patients were successfully fitted with blood vessels engineered solely from their own living tissue, making it easier and safer for them to use dialysis machines, the AFP reported.
The results suggest that doctors might one day be able to custom-produce blood vessels for patients with circulatory problems in their hearts or legs.
Lab-grown blood vessels were implanted into 10 patients with advanced kidney disease in Argentina and Poland from 2004 to 2007, wrote Todd McAllister of Cytograft Tissue Engineering in California and colleagues in the New England Journal of Medicine.
The researchers published early results for two of these patients in 2005 and preliminary findings for another 4 patients two years later.
Dialysis patients compensate for kidney failure by having their blood filtered three times a week on the machines to remove wastes and excess fluid from the body.
During the procedure a short bypass, or shunt, must be inserted between an artery and a vein for the process to work. This additional bit of arterial plumbing can be taken from an existing vein in some cases.
But many patients have the bridge made from plastic, often resulting in a significantly higher failure rate.
The patients in the study were fitted with new shunts grown in a laboratory from their own adult cells in a technique called cell-sheet biofabrication.
The process starts with a skin biopsy. Then fibroblast cells are grown in a single-layer cell culture, rolled up and chemically washed to remove living cells.
After being encased with another sheet of living cell tissue, the resulting tube-like membrane is then implanted in the patient’s arm.
However, the researchers acknowledged that three of the grafts failed during an initial safety phase where the new bypasses were assessed for mechanical stability while the patients continued to receive traditional dialysis.
Two other patients left the study for reasons unrelated to the trials, while the five remaining patients had grafts functioning for dialysis for between six and 20 months after implantation.
The study concluded that doctors and scientists could provide the requisite mechanical strength in a tissue-engineered construct without relying on synthetic biomaterials.
“The fact that our long-term intervention rate was so low — even with this high risk group — offers hope to patients suffering from end-stage renal disease,” it said.
Epidemiological studies show that there are between 1.5 and 2.0 million people receiving dialysis treatment around the world, and many millions more in need.
The cost of the innovative technique would need to come down before it was commercially viable, according to experts in a commentary also published in The Lancet.
McAllister said he and his team plan to test similar devices in patients with heart and leg problems.
“It’s basically a piece of plumbing to bypass blockages,” he said.
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