Much like finding water on Mars and the fight to be the next President of the USA, pluripotent stem cell-derived mini-organs (or organoids) are big news at the moment. A recent study, featured here at EpiGenie, used a brain organoid generated from patient-specific induced pluripotent stem cells (iPSCs) to unravel the molecular causes behind autism.
Now, two studies published in Nature and Nature Biotechnology move these little stem cell-derived organoids another big step forward. Both studies report the successful generation of functional kidney organoids from human iPSCs, thus bringing us nearer to the ultimate goal of patient-specific stem cell-derived transplantable organs.
These exciting new studies found that:
- A specific combination of small molecule inhibitors and growth factors given for specific durations at specific times could coax iPSCs into becoming kidney progenitor cells.
- Three-dimensional cultures of treated iPSCs spontaneously formed into kidney organoids displaying signs of the intricate inner workings of the kidney.
- Organoids contained nephron-like structures (the blood filtering unit of the kidney) surrounded by the collecting duct network required for fluid reabsorption/secretion and urine production.
- Each nephron unit contained the various required kidney cell types organized in the proper fashion.
- Overall, the organoids recapitulated critical developmental stages and resembled fetal/immature kidneys at the end of the culture process.
- Importantly, the organoids displayed kidney-like functions.
- Reabsorption of specific compounds, important for their blood filtering ability.
- Appropriate reaction to toxic compounds, demonstrating their potential use in toxicological drug testing.
While these stem cell-derived kidney organoids are useful for several fascinating endeavors, such as toxicological screening and disease modeling, they still have some growing up to do before they can call themselves fully functional complete “organs”.
However, the groups behind these studies also hope to take the next big step forward and use these stem cell derived-organoids as the foundation for clinically relevant patient-specific transplantable cells, and of course, fully functional and mature kidneys.