Cataracts is the leading cause of blindness worldwide. The only option for those affected is surgery, an expensive and invasive procedure that’s unavailable to many in the developing world. But perhaps we’re not too far off from changing that, as another study is dangling the possibility of using eye drops as a viable alternative, potentially offering a practical treatment to the 20 million or so people affected worldwide.
Cataracts, or cloudy lenses, arise when lens proteins called crystallins begin to twist into the wrong conformation and clump together. Crystallins, a major constituent of the lens’ fiber cells, normally help keep the lens transparent by preventing proteins from forming aggregates that diffract incoming light. They do this by acting as molecular “chaperones” that maintain the solubility of lens proteins.
As we age, these crystallin proteins can become damaged and consequently cluster into fibers much like what we see in the brains of those with Alzheimer’s. Unfortunately, these tangles of protein are much more stable than the normal, native form, and since you stop making crystallins when you’re born, their formation depletes the eye of healthy, functional versions.
Armed with this knowledge, authors of the current study, published in Science, went on a hunt for drug compounds that could act as “pharmaceutical chaperones,” molecules that stick to and stabilize the natural state of a protein. Specifically, they wanted chemicals that could selectively hang on to the soluble form of crystallin proteins and thus prevent them from clumping together.