Mayo Clinic researchers have demonstrated they can permanently transfer a functioning gene to targeted tissues within the eye. This success in animals is a first step in using gene therapy to treat glaucoma, a major cause of blindness worldwide. The research findings appear in the online issue of the leading vision science journal Investigative Ophthalmology and Visual Science.
Pressure build up within the eyeball due to malfunctioning fluid drainage in the front of the eye is one of the causes of glaucoma. Blindness occurs when pressure progressively damages the optic nerve at the back of the eye. Eye specialists have long hoped for a permanent way to fix the malfunctioning outflow—and they may now be a step closer because of the Mayo Clinic research.
“The main message here is that a specific kind of gene vector—a lentiviral vector—could be engineered to work really well as a delivery system to the particular tissue involved in glaucoma,” says Eric Poeschla, M.D., a virologist in Mayo Clinic’s Molecular Medicine program and the lead investigator on the project.”
This work has at least three important implications for gene therapy for glaucoma:
1. Glaucoma is a chronic disease that now is treated with surgery and then daily eye drops for the rest of the patient’s life. This treatment does not prevent blindness in many cases. Glaucoma affects 70 million people worldwide, many over age 65. Any new therapies would be welcome advances if they were permanent and eliminated the daily eye drops. This study’s one-year success record offers hope of a permanent transfer in humans.
2. The Mayo Clinic researchers are the first to show that a lentiviral vector can effectively deliver genetic cargo to this glaucoma-related target in the eye.
Says Dr. Poeschla, “The results meet three criteria that have represented a main hurdle: enough delivery to enough cells; targeted delivery to the relevant cells; and permanence.’’ He emphasizes that the Mayo Clinic research is still in its early stages and that no human participants have been involved.
3. The approach may be well suited to carry a gene that can prevent blindness by fixing the defect in the eye’s fluid outflow system. Several such potential therapeutic transferable genes are the subject of current research at Mayo but are not ready for human testing.
“Using eye drops every day, lifelong, is very difficult for anyone, and there are many for whom the drops don’t work, so the field as a whole recognizes that better treatments are needed to prevent blindness. That’s why there’s been a lot of interest in the concept of gene therapy as a way of permanently correcting the problem of this chronic disease,’’ says Dr. Poeschla.
Adopted from the following source: Mayo Clinic