Neurotrophic rationale in glaucoma: A TrkA agonist, but not NGF or a p75 antagonist, protects retinal ganglion cells in vivo

Authors

  • ZhiHua Shi,

    1. Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
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  • Elena Birman,

    1. Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
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  • H. Uri Saragovi

    Corresponding author
    1. Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
    2. Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada H3T 1E2
    3. Department of Oncology and the Cancer Center, McGill University, Montreal, Quebec, Canada H3T 1E2
    4. Bloomfield Center for Research in Ageing, McGill University, Montreal. Quebec, Canada H3T 1E2
    • Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2
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Abstract

Glaucoma is a major cause of vision impairment, which arises from the sustained and progressive apoptosis of retinal ganglion cells (RGC), with ocular hypertension being a major risk or co-morbidity factor. Because RGC death often continues after normalization of ocular hypertension, growth factor-mediated protection of compromised neurons may be useful. However, the therapeutic use of nerve growth factor (NGF) has not proven effective at delaying RGC death in glaucoma. We postulated that one cause for the failure of NGF may be related to its binding to two receptors, TrkA and p75. These receptors have distinct cellular distribution in the retina and in neurons they induce complex and sometimes opposing activities. Here, we show in an in vivo therapeutic model of glaucoma that a selective agonist of the pro-survival TrkA receptor was effective at preventing RGC death. RGC loss was fully prevented by combining the selective agonist of TrkA with intraocular pressure-lowering drugs. In contrast, neither NGF nor an antagonist of the pro-apoptotic p75 receptor protected RGCs. These results further a neurotrophic rationale for glaucoma. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.

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