Dr. Grossman’s Blog

A study by Alcon Research Ltd. and the University of Iowa suggests that increased expression of the protein sFRP-1, an inhibitor of cell signaling through WNT proteins, may be responsible for elevated IOP in individuals with glaucoma.

Glaucoma is a major cause of visual impairment and blindness throughout the world. An important risk factor for the disease is an increase in the intraocular pressure (IOP). IOP, the fluid pressure in the eye, is determined by the rate of production of the clear fluid in the eye and the rate at which this fluid flows out of the eye. Although it is thought that impaired outflow of fluid from the eye causes the increased IOP in individuals with glaucoma, the exact molecular mechanisms of the disease are not fully understood.

Researchers found increased expression of sFRP-1 in eye tissue from patients with glaucoma; when they treated donor human eyes with sFRP-1 ex vivo, these eye tissues had less outflow of fluids compared to untreated eyes. The sFRP-1-treated donor eyes also had reduced expression of a WNT-related protein.

To further support this relationship, mice manipulated to express sFRP-1 in the eye displayed increased IOP. When a downstream suppressor of WNT signaling was inhibited, the problem was resolved.

The authors believe that restoring WNT signaling might provide a new method for treating patients with glaucoma in the future.

Read more about glaucoma, including information on lifestyle choices and nutrition for maintaining healthy vision.

SOURCE: “Increased expression of the WNT antagonist sFRP-1 in glaucoma elevates intraocular pressure”, Wang, et al, Journal of Clinical Investigation, 118(3): 1056-1064 (2008).