A team of researchers from Sun Yat-sen University in China and here in California at my graduate alma mater UCSD has published a remarkable, new report in Nature reporting human lens regeneration in cataracts. This is a truly amazing idea that endogenous stem cells can regrow new lenses. I wonder if we are on a path to someday make entire new eyes via stem cells in future decades.
In the Lin, et al. paper entitled, “Lens regeneration using endogenous stem cells with gain of visual function”, the team describes how a cataract surgery that preserves endogenous lens stem cells in the lens capsule, allows for lens regrowth after surgery. They were able to do this in animals and in human infants.
The key seems to be preservation of what they call “lens epithelial stem/progenitor cells” or LECs. Conventional cataract surgery fails to preserve LECs and involves insertion of an artificial lens. In this new approach the researchers let the LECs regenerate a new lens. See Figure 2 from the paper above. You can also see the table on the human patient data from the clinical trial here.
They end their article on an optimistic note:
“In summary, the current surgical procedure for cataract treatment inadvertently destroys the integrity of the lens capsule and the very LECs that hold the regenerative key to lens restoration. It is also associated with numerous side-effects and a significant risk of complications, particularly in infants. To overcome these problems, we have developed a new, minimally invasive surgical method that allows regeneration of a functional lens with refractive and accommodative abilities, and with greater visual axis transparency. This new cataract treatment uses endogenous stem cells to replenish the human ocular lens, and provides a fresh paradigm for organ and tissue regeneration.”
There are remain at least three billion-dollar open questions.
- What will happen to these lens over time as the infants grow up? If their vision is poor compared to those receiving artificial lenses then that’s going to be much less exciting.
- Will this approach work in older folks, who make up the vast majority of cataract patients? Infants could well have an enormous stockpile of LECs, whereas as we age these cells could disappear…but then again, maybe not. Maybe even those of us decades into life have enough LECs to grow news lens.
- Could these cells be used to make replacement lens via bioengineering in the lab that could then be transplanted to replace lenses with cataracts? Long term this seems like the most promising route rather than relying upon the vagaries of endogenous regrowth, particularly if the answer to the first question is “no”.
Overall this is an exciting paper and once I get the current grant I’m working on done, I have this paper on my list for a more thorough read.