Scientists grow mini-kidney in lab

But recently Australian scientists have created tiny kidneys in a dish in a key advance towards lab-grown replacement organs and crash test dummy tissues for gauging drug toxicity.

The results of the Australian research show how the new “mini kidney” has all the cell types present in human kidneys.

“These kidneys have something like 10 or 12 different cell types in them … all from the one starting stem cell”, said Professor Little.

“Creating a model kidney containing many different kidney cell types also opens the door for cell therapy and even bioengineering of replacement kidneys”.

To test whether the organoids reacted to toxic drugs in the same way as healthy human kidneys, the scientists exposed them to the cancer drug, cisplatin, and found that they suffered similar damage.

“What we have is the equivalent of a first-trimester human kidney”, said Melissa Little, development biologist at the Murdoch Childrens Research Institute in Melbourne, Australia, and a lead author of the study.

The study was published in scientific journal Nature, and detailed how Little and her colleagues turned an ordinary fibroblast skin cell into a functioning kidney. The lab-generated organs are also missing the waste drainage outlet that’s vital to kidney function in an adult.

The researchers from Australia and the Netherlands grew their “kidney-like structure” from induced pluripotent stem (iPS) cells – adult cells reprogrammed into a neutral state from which they can be coaxed to develop into other cell types. A pharmaceutical company can spend millions of dollars developing a drug, only to discover when they begin human trials that the compound is harmful and has to be ditched. The organ has two functionalities – collecting ducts, which assist with electrolyte and fluid balance, and nephrons, which are blood-filtering units. The organoid is not advanced enough to do all the very complicated balancing that a completely formed kidney does.

In the meantime, the primitive organs could possibly be used to help save failing kidneys by transplanting parts of them into patients, she says. Whether that will work remains to be seen. The patient wouldn’t need to take immune-suppressing drugs to make the body tolerate the new organ.

MELISSA LITTLE: I think what’s really great is that, at this size and with this complexity, and this accuracy because it really is like a normal human developing kidney, we can do things with it now and that’s because we can make a stem cell for example from someone’s who’s got kidney disease that might have a mutation that’s caused their disease.

“This is taking quite a big step forward”, Davies says, toward that goal.