First-ever 'mini-kidney' organs created from human stem cells

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Mouse embryonic kidney cells (red) coax human stem cells to grow into nascent mushroom-shaped buds (blue and green).--Courtesy of the Salk Institute

Three-dimensional kidney structures created for the first time in a laboratory by scientists at the Salk Institute for Biological Studies could provide a way to test new drugs that treat kidney disease and restore kidney function.

While other scientists have been able to create precursors of kidney cells using stem cells, the Salk team claims to be the first to coax human stem cells into forming 3-D cellular structures that imitate those found in human kidneys. The research was published Nov. 17 in Nature Cell Biology.

Ignacio Sancho-Martinez, a Salk researcher and lead author of the study, told FierceBiotech Research that previous attempts to differentiate human stem cells into renal cells have relied on using a scaffold to essentially guide tissue growth.

"In our case everything was formed spontaneously during development," he said.

In separate attempts, scientists coaxed both human embryonic stem cells and induced pluripotent stem cells (iPSCs)--human cells from the skin that have been reprogrammed into their pluripotent state--into cells similar to those found in the ureteric bud, an early developmental structure of the kidneys. The investigators then guided these cells to further differentiate into 3-D organ structures by tapping into certain essential growth factors--molecules that direct the process in which stem cells become specific tissues--and culturing them with kidney cells from mice.

The Salk team tested the discovery on iPSCs taken from a patient clinically diagnosed with polycystic kidney disease (PKD), a genetic disorder characterized by several fluid-filled cysts that can lead to decreased kidney function and kidney failure. Using their newly created method, the scientists were able to produce mini-kidney structures from the patient's iPSCs.

In the short-term future, Sancho-Martinez said his team envisions that the mini-kidney structures will be used as a platform to screen and test compounds that could treat a variety of kidney diseases. The long-term goal, Sancho-Martinez said, is to generate a fully humanized kidney.

The Salk team is looking to partner with pharmaceutical companies interested in its technology, which could aid in drug-discovery efforts as well as in safety and efficacy studies. 

- read the press release
- see the study abstract

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