Age related macular degeneration (AMD) is the third cause of visual impairment worldwide and the leading cause of blindness in higher income countries with aging populations. It is estimated that by 2020 196 million people will suffer AMD.
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Several years ago, treatment of AMD had a breakthrough with the application of treatments targeting the vascular endothelial growth factor (VEGF). VEGF-inhibitors are currently injected straight into the eye, but new options are under research to improve outcome and decrease the invasiveness of the procedure. As a couple of examples companies like Regenxbio are developing gene therapies to neutralize VEGF, whereas scientist at the University of Birgmingham are hoping to replace the injections with eye drops.
However, these treatments are only effective in the wet form of AMD, which is caused by new blood vessels growing into the subretinal space. A bigger challenge remains to treat the dry form of AMD, for which currently the only treatment is the oral use of antioxidant vitamin supplements that may slow progression of the disease.
Now, a new discovery could be key to treatment of AMD. Scientists at the National Institutes of Health´s National Eye Institute have been able to identify 6 genomic regions associated with AMD. They compared eye tissue from AMD and non-AMD deceased tissue donors and identified 34 genetic areas associated to AMD. To determine which of these are actually affecting the biology of AMD, they used computational biology to compare genes that express proteins in the retina with all the genetic variants previously identified.
The team, led by Anand Swaroop, has further pinpointed 2 genes as novel potential drug targets: B3GLCT and BLOC1S1, both associated with accumulation of unwanted proteins in the eye. Swaroop is now planning to identify how these genes may affect the development of AMD and help develop new therapeutic strategies to treat the disease or even affect its onset. By identifying key biochemical pathways involved in the disease and therapies can be developed that could interrupt these pathways.
Other approaches that are looking promising for AMD patients are regenerative treatments that try to repair tissues destroyed by AMD.
Scientists can now derive stem cells from a patient´s own skin or blood, which can in turn be directed to turn into retinal pigment epithelium (RPE). The goal is to implant these cells into the patient´s eye to preserve and restore vision.
Just a year ago a publication in Nature Biotech described the implantation of RPE cells derived from stem cells to treat people with sudden severe sight loss from severe wet AMD in a phase I clinical study. The study was a major breakthrough since it could be applied to both types of AMD, not only stopping progression of the disease but also improving the patient´s vision. One of the inventors, Professor Pete Coffey, hopes this will lead to an affordable off-the-shelf therapy that could be made available to patients in the next 4 years.
If you´re interested in new solutions for AMD, check out these and other technology advances:
- Microarray Analysis of Gene Expression in the Aging Human Retina
- Novel Methods for Generating Retinal Pigment Epithelium Cells from Induced Pluripotent Stem Cells
- Treatment of Retinal Degeneration with Gene Transfer of Components of the Anti-oxidant Defense System
- Anti-miRNAs for the Treatment and Prevention of AMD
- Gene Therapy targeting disposal of toxic intracellular lipid debris and lipofuscin
- for Macular Degeneration
- NADPH Inhibition Compounds for Treatment of AMD