Human kidneys could be made now

Researchers say they have successfully grown functional kidneys inside rats using just a few donor stem cells, an advance with significant implications for human organ transplantation.

For patients with end-stage renal disease, a kidney transplant is the only hope for regaining quality of life, according to the study. Yet many of these patients will never undergo transplant surgery due to a chronic shortage of donor kidneys, said researchers from the National Institute for Physiological Sciences in Japan.

With 95,000 patients on the waiting list for a donor kidney in the US alone, demand far outstrips supply, they said. However, researchers have been working on ways to grow healthy organs outside the human body.One such method, called blastocyst complementation, has already produced promising results. Researchers take blastocysts, the clusters of cells formed several days after egg fertilisation, from mutant animals missing specific organs and inject them with stem cells from a normal donor, not necessarily of the same species.

The stem cells then differentiate to form the entire missing organ in the resulting animal. The new organ retains the characteristics of the original stem cell donor, and can thus potentially be used in transplantation therapy.