Imagine what it would be like if you were a young boy and your urethra – the pipe that’s supposed to carry urine from your bladder to your penis – was irreparably damaged or traumatically destroyed.
You’d be facing a probable lifetime of incontinence, infection, pain, bleeding and difficulty urinating.
Although small defects in the tube can be repaired, larger defects are treated with a tissue graft, usually taken from skin or the lining of the cheek. But these grafts fail in half of the cases.
Now imagine if scientists could grow you a new urethra.
Because that’s exactly what researchers from the Institute for Regenerative Medicine at Wake Forest University Baptist Medical Center in North Carolina, have done.
Watching human organs take shape in a lab dish is no longer, it seems, only the realm of science fiction.
The research team, led by Dr. Anthony Atala used patients’ own cells to grow urethras in the lab and have successfully used them to replace damaged tissue in five young Mexican boys.
Six years after surgery, urine flow tests and tube diameter measurements show the tissue-engineered urethras are still working.
The study, published in the Lancet, represents a first in the growing field of regenerative medicine, which doctors hope will eventually lead to ways to repair injuries and eventually replace whole organs.
“When an organ or tissue is irreparably damaged or traumatically destroyed, no amount of drugs or mechanical devices will restore the patient back to normal. Totally grown in the laboratory, these urethras highlight the power of cell-based therapies“ said Chris Mason, a regenerative medicine expert at University College London, who was not involved in the research.
So how did they do it?
Basically they took a very small piece of tissue, about half the size of a postage stamp. To that, they added a soup of growth factors that nourished the cells and encouraged them to multiply into large quantities. The team made two cell types: muscle cells for the tube’s outer layer and endothelial cells — cells that line blood vessels and other tubular structures — for the inner layer.
Once they had grown enough cells, they applied them onto a biodegradable mesh that was shaped into a tube and sized to be a perfect fit for the patient. Then they heated them in an incubator to allow the cells to start to form sheets.
After a week of incubation to allow the cells to take to the mesh, the lab-grown grafts were surgically transplanted into the patients.
Once implanted, the sheets of cells started forming new tissue, and after about four weeks, they were able to remove the urinary catheter and the boys were able to urinate through the new urethras. Biopsies showed the engineered urethras had normal layers of epithelial and smooth muscle within three months.
Six years in the grafts are doing well, looking and functioning exactly like a normal urethra in the five boys who are now entering their teens.
Although larger studies will be needed before the treatment can be widely used, this data shows the potential power of cell-based therapies.
Eventually, it is hoped that regenerative medicine will be able to cure the large unmet medical needs of our generation including: blindness, diabetes, heart failure, Parkinson’s disease and stroke.
As always, SRxA’s Word on Health will be watching and will bring you new developments as they’re announced.
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