By stripping a kidney of its cells and repopulating it with new ones, scientists have shown in a rat that a bioengineered kidney can function to some extent like a normal one. The work, published April 14 in Nature Medicine, reveals that the protein scaffold of a kidney provides the architecture and chemical cues that new cells need to adopt the roles of kidney cells.

The results may one day assist in alleviating the transplant organ shortage by providing patients with refurbished kidneys. If bioengineering techniques can make use of kidney scaffolds that come from animals or cadavers whose kidneys would otherwise have been discarded, it could provide many kidneys for transplant, says Shay Soker, a cell biologist at Wake Forest University in Winston-Salem, N.C., who was not involved in the study.

The study deserves high marks for advancing techniques that others may adopt in bioengineering kidneys, says Edward Ross, a nephrologist at the University of Florida in Gainesville. “This is still very early, but they’ve come a long way. It’s really beautiful work.”

The kidney is a complex organ that performs the delicate work of filtering waste out of the blood and keeping electrolytes balanced. When kidneys fail, a person’s only options are dialysis or a kidney transplant. But candidates for kidney transplant far outnumber available donors.