A study published Sept. 9 in The Journal of Clinical Investigation promises a new way to tackle glaucoma, a leading cause of blindness. It appears that the basis of the disease has finally been discovered.
Glaucoma is a condition in which pressure in the eye increases because fluid in the anterior chamber does not drain properly, destroying retinal ganglion cells and, ultimately, the optic nerve. The culprit is known as Schlemm’s canal, a part of the lymphatic system that is critical for drainage in the eye. As it becomes clogged, fluid is retained.
For the first time, Northwestern Medicine scientists identified the molecular building blocks responsible for constructing the vessels that provide drainage.”This is a big step forward in understanding the cause of the disease that steals the eyesight from 60 million people worldwide,” said senior study author and Northwestern Medicine nephrologist Susan Quaggin, M.D. “This gives us a foothold to develop new treatments.”
The critical chemical signaling pathway of a healthy Schlemm’s canal necessary for its growth and development requires a lock and key to open. Tie2 has been identified as the lock and the key appears to be a growth factor called angiopoietin. Mice with either missing were unable to generate the cells required by Schlemm’s canals and developed glaucoma.
“We really nailed that pathway as being critical,” Quaggin said. “Now we know these two substances are key factors in the development of glaucoma, which wasn’t known before. Our goal now is to grow new ‘pipes’ or vessels to cure the glaucoma.”
Collaborating with Amani Fawzi, M.D., an associate profession of ophthalmology and Xiaorong Liu, an assistant professor of ophthalmology, both at Feinberg, and Northwestern scients Samuel Stupp, Quaggin hopes to develop a nonfiber eye drop that activiates regrowth of Schlemm’s canals.
“Just imagine if we could grow a bigger Schlemm’s canal in anybody with glaucoma to lower the pressure in the eye,” Quaggin said. “That’s what we’re hoping for with this new eye drop.”
In the meantime, there are other ways to treat glaucoma. Inn a recent study published in the Journal of Cataract & Refractive Surgery, a combination of endocyclophotocoagulation (ECP) and phacoemulsification “demonstrated a statistically significant reduction of both inter-ocular pressure (IOP) and glaucoma medications compared to phacoemulsification alone.