Researchers are step by step establishing a better understanding of kidney regeneration that should improve efforts to spur regrowth and repair through stem cell treatments and other forms of regenerative medicine:
Doctors and scientists have for years been astonished to observe patients with kidney disease experiencing renal regeneration. The kidney, unlike its neighbor the liver, was universally understood to be a static organ once it had fully developed. "We wanted to change the way people thought about kidneys - about internal organs altogether. Very little is known even now about the way our internal organs function at the single cell level. This study flips the paradigm that kidney cells are static - in fact, kidney cells are continuously growing, all the time."
[Researchers] conducted a study using a "rainbow mouse" model, a mouse genetically altered to express one of four alternative fluorescent markers called "reporters" in each cell. "We were amazed to find that renal growth does not depend on a single stem cell, but is rather compartmentalized. Each part of the nephron is responsible for its own growth, each segment responsible for its own development, like a tree trunk and branches - each branch grows at a different pace and in a different direction."
Using the rainbow mouse, the researchers were able to pinpoint a specific molecule responsible for renal cellular growth called the "WNT signal." Once activated in specific precursor cells in each kidney segment, the WNT signal results in robust renal cellular growth and generation of long branches of cells. "Our aim was to use a new technique to analyze an old problem. No one had ever used a rainbow mouse model to monitor development of kidney cells. It was exciting to use these genetic tricks to discover that cellular growth was occurring all the time in the kidney - that, in fact, the kidney was constantly remodelling itself in a very specific mode."
"This study teaches us that in order to regenerate the entire kidney segments different precursor cells grown outside of our bodies will have to be employed. In addition, If we were able to further activate the WNT pathway, then in cases of disease or trauma we could activate the phenomena for growth and really boost kidney regeneration to help patients. This is a platform for the development of new therapeutics, allowing us to follow the growth and expansion of cells following treatment."