Implantable, Bioengineered Rat Kidney: Transplanted Organ Produces Urine.

Bioengineered rat kidneys developed by Massachusetts General Hospital (MGH) investigators successfully produced urine both in a laboratory apparatus and after being transplanted into living animals.

In their report the research team describes building functional replacement kidneys on the structure of donor organs from which living cells had been stripped, an approach previously used to create bioartificial hearts, lungs and livers.

"What is unique about this approach is that the native organ's architecture is preserved, so that the resulting graft can be transplanted just like a donor kidney and connected to the recipient's vascular and urinary systems," says Harald Ott, MD, PhD, of the MGH Center for Regenerative Medicine, senior author of the Nature Medicine article. "If this technology can be scaled to human-sized grafts, patients suffering from renal failure who are currently waiting for donor kidneys or who are not transplant candidates could theoretically receive new organs derived from their own cells."

Around 18,000 kidney transplants are performed in the U.S. each year, but 100,000 Americans with end-stage kidney disease are still waiting for a donor organ. Even those fortunate enough to receive a transplant face a lifetime of immunosuppressive drugs, which pose many health risks and cannot totally eliminate the incidence of eventual organ rejection.

Bioengineered kidneys transplanted into living rats from which one kidney had been removed began producing urine as soon as the blood supply was restored, with no evidence of bleeding or clot formation. The overall function of the regenerated organs was significantly reduced compared with that of normal, healthy kidneys, something the researchers believe may be attributed to the immaturity of the neonatal cells used to repopulate the scaffolding.