Stem cell kidneys prompt treatment hope

Miniature kidneys grown from stem cells in a Petri dish are helping scientists move towards a treatment for a disease which causes organ failure.

Polycystic kidney disease (PKD) is an inherited condition that results in cysts – sometimes numbering in the thousands – growing on both kidneys. The cysts can affect the healthy organ tissues, causing them to stop working.

In a paper published in the journal Nature Materials, a team led by Benjamin Freedman of the University of Washington department of medicine reports on the creation of functional mini-kidneys – “organoids” – from stem cells, and then using them to test various behaviours of cysts.

The team found that by adjusting certain physical limits in the environment of the kidneys, the rate and size of cyst formation changed.

“Beforehand, we had shown that these organoids could form PKD-like cysts, but what’s new here is that we’ve used the model to understand something fundamental about that disease,” says Freedman.

The team found that if the mini-organs were left free to float in their Petri dish mediums they developed large, hollow cysts. If, however, they were secured to a substrate, then the cysts remained small.

The findings suggest that if the mechanisms that affect cyst size and density in actual kidneys can be better understood, treatment targets might then be identified.

“We’ve discovered that polycystin proteins, which are causing the disease, are sensitive to their micro-environment,” says co-author Nelly Cruz.

“Therefore, if we can change the way they interact or what they are experiencing on the outside of the cell, we might actually be able to change the course of the disease.”