Scientists have previously shown that embryonic tissue transplants can be used to grow new kidneys inside rats. In their latest study, though, they put the new kidneys to an unprecedented and critical test, removing the rat's original kidneys and placing the new kidneys in position to take over for them. The new kidneys were able to successfully sustain the rats for a short time.
"We want to figure out how to grow new kidneys in humans, and this is a very important first step," says Marc R. Hammerman, M.D., the Chromalloy Professor of Renal Diseases and leader of the study. "These rats lived seven to eight days after their original kidneys were removed, long enough for us to know that their new kidneys worked."
The study will appear in the July/August issue of Organogenesis, a new scientific journal. It is also available online.
Hammerman is a leader in the burgeoning field of organogenesis, which focuses on growing organs from stem cells and other embryonic cell clusters known as organ primordia. Unlike stem cells, organ primordia cannot develop into any cell type--they are locked into becoming a particular cell type or one of a set of cell types that make up an organ.
"Growing a kidney is like trying to construct an airplane--you can't just make a single part like a propeller, you have to build several different parts and systems and get them all working together properly," Hammerman explains. "Fortunately, kidney primordia already know how to grow different parts and self-assemble into a kidney--we just have to give them the right cues and a little assistance at various points."
For the study, Hammerman and coauthor Sharon Rogers, research instructor in medicine, gave renal primordia transplants to 5-
Contact: Michael C. Purdy
Washington University School of Medicine