Mechanisms of Optic Nerve Stroke Neuroprotection

University Of Maryland Baltimore, Baltimore MD

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Abstract

DESCRIPTION (provided by applicant): Nonarteritic anterior ischemic optic neuropathy (NAION) is an optic nerve (ON) infarct, and the most common cause of sudden optic nerve (ON) related vision loss, NAION affects ~15,000 individuals/year and has no effective treatments. Little is known about the mechanisms in NAION pathophysiology. Our lab developed the first rodent and primate NAION models that have been validated for nearly every finding found in NAION, and us to critically dissect NAIONs likely processes. We have determined that early and late inflammatory changes play a key role in NAION model development and damage. Soon after NAION model induction, ON head edema and a compartment syndrome occur along with soluble inflammatory cytokine expression and progressive ischemia. Later (>3d) changes include significant cellular inflammatory infiltration, with increased M1 (degenerative macrophage response) and decreased M2 (regenerative macrophage response) activities, and progressive axon- and oligodendrocyte damage. These responses ultimately result in retinal ganglion cell (RGC) and oligodendrocyte death. We identified prostaglandin J2 (PGJ2) as the first agent that can potentially treat early stage disease. In aim 1, we will separately evaluate PGJ2's neuroprotective mechanisms, confirming their individual identities and their maximal effects. We will then determine whether these mechanisms act synergistically, to maximize neuroprotection. In aim 2, we will determine whether selectively immunomodulating the neuroprotective M2 macrophage inflammatory response will reduce RGC and myelin dysfunction and cellular death, and improve post-infarct recovery. Results of these interventions will be evaluated using a variety of techniques, to quantify effects at the gene expression level, histochemically and functionally. This combination early and later approaches is designed to maximize development of clinically effective treatments for NAION and related diseases, and greatly improve post- NAION recovery.