Valproic acid prevents retinal degeneration in a murine model of normal tension glaucoma

et al. 2015

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PURPOSE. To assess the therapeutic potential of spermidine in mice with excitatory amino acid carrier 1 (EAAC1) deletion (EAAC1 knockout [KO] mice), a mouse model of normal tension glaucoma.METHODS. Spermidine, at 30 mM in drinking water, was administered to EAAC1 KO mice from 5 to 12 weeks old. Optical coherence tomography, multifocal electroretinograms, and the measurement of intraocular pressure (IOP) were performed at 5, 8, and 12 weeks old. Histopathology analyses were carried out at 8 and 12 weeks old, and immunoblot and immunohistochemical analyses of 4-hydroxy-2-nonenal (4-HNE) in the retina were performed at 8 weeks old. RESULTS. Spermidine ameliorated retinal degeneration and improved visual function in EAAC1KO mice at both 8 and 12 weeks old, without affecting IOP. A significant increase of 4-HNE was observed in vehicle-treated EAAC1 KO mice, but spermidine treatment reduced this increase, suggesting that spermidine alleviated the severity of the glaucoma-like phenotype by acting as an antioxidant. CONCLUSIONS.The results from this study suggest that oral spermidine administration could be a useful treatment for retinal degenerative disorders including glaucoma.

supporting

confidence: 60%

mentioning

confidence: 99%

Spermidine Ameliorates Neurodegeneration in a Mouse Model of Normal Tension Glaucoma

Noro

Namekata

et al. 2015

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“…Despite some limitations, such animal models are essential for preclinical research and our NTG models have been providing useful information regarding NTG therapy easily and speedily. We recently reported that widely prescribed drugs, such as valproic acid, 45 candesartan, 38 and edaravone 7 suppressed RGC death in EAAC1 or GLAST KO mice without altering IOP. In addition, every other day fasting, a form of caloric restriction, suppressed RGC death in EAAC1 KO mice under normal IOP.…”

Section: Discussionmentioning

confidence: 99%

“…The intensities were analyzed using ImageJ (http://imagej.nih.gov/ij/; provided in the public domain by the National Institutes of Health, Bethesda, MD, USA). 45 …”

Section: 42mentioning

confidence: 99%

Topical Ripasudil Suppresses Retinal Ganglion Cell Death in a Mouse Model of Normal Tension Glaucoma

Akaiwa

Namekata

et al. 2018

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METHODS. Topical administration (5 lL/day) of two different concentrations of ripasudil (0.4% and 2%) were applied to EAAC1 KO mice from 5 to 12 weeks old. Optical coherence tomography, multifocal electroretinograms, the measurement of intraocular pressure (IOP), and histopathology analyses were performed at 5, 8, and 12 weeks old. Retrograde labeling of retinal ganglion cells (RGCs), immunoblot, and immunohistochemical analyses of phosphorylated p38 mitogen-activated protein kinase (MAPK) in the retina were performed at 8 weeks old.RESULTS. Topical ripasudil ameliorated retinal degeneration and improved visual function in EAAC1 KO mice at both 8 and 12 weeks old. Ripasudil reduced IOP and strongly suppressed the phosphorylation of p38 MAPK that stimulates RGC death in EAAC1 KO mice.CONCLUSIONS. These results suggest that, in addition to IOP reduction, ripasudil prevents glaucomatous retinal degeneration by neuroprotection, which is achieved by suppressing celldeath signaling pathways.

“…We recently reported that valproic acid (VPA) protects RGCs from glutamate neurotoxicity in a mouse model of normal tension glaucoma. 24,38 VPA is a short chain fatty acid that has been used clinically worldwide for treatment of epilepsy since the 1970s. VPA has been shown to exert antioxidant properties in the brain following ischemia/reperfusion injury and in motor neurons following spinal cord injury.…”

Section: Discussionmentioning

confidence: 99%

Edaravone Prevents Retinal Degeneration in Adult Mice Following Optic Nerve Injury

Akiyama

Guo

et al. 2017

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PURPOSE.To assess the therapeutic potential of edaravone, a free radical scavenger that is used for the treatment of acute brain infarction and amyotrophic lateral sclerosis, in a mouse model of optic nerve injury (ONI).METHODS. Two microliters of edaravone (7.2 mM) or vehicle were injected intraocularly 3 minutes after ONI. Optical coherence tomography, retrograde labeling of retinal ganglion cells (RGCs), histopathology, and immunohistochemical analyses of phosphorylated apoptosis signal-regulating kinase-1 (ASK1) and p38 mitogen-activated protein kinase (MAPK) in the retina were performed after ONI. Reactive oxygen species (ROS) levels were assessed with a CellROX Green Reagent.RESULTS. Edaravone ameliorated ONI-induced ROS production, RGC death, and inner retinal degeneration. Also, activation of the ASK1-p38 MAPK pathway that induces RGC death following ONI was suppressed with edaravone treatment. CONCLUSIONS.The results of this study suggest that intraocular administration of edaravone may be a useful treatment for posttraumatic complications.Keywords: edaravone, oxidative stress, neuroprotection, ASK1, retinal ganglion cell T raumatic optic neuropathy is a common clinical problem that occurs in 0.5% to 5% of patients with closed head injury.1 Damage to the optic nerve induces secondary swelling within the optic canal, accompanied by subsequent retinal ganglion cell (RGC) loss and optic nerve atrophy.2 Although no large natural history or randomized controlled trials have been published, corticosteroid therapy and optic canal decompression surgery are not considered to be effective for patients with traumatic optic neuropathy.3 Research into finding therapeutic targets for treatment of traumatic optic neuropathy indicated that neuroprotection might be an effective strategy and studies using an optic nerve injury (ONI) model in rodents have provided useful information. For example, neurotrophins, such as brain-derived neurotrophic factor and ciliary neurotrophic factor, protect retinal RGCs in an ONI model. [4][5][6] Also, inhibitors of glutamate receptors, tumor necrosis factor receptors, and nitric oxide synthase may be effective for RGC protection. 7-11The ONI model mimics some aspects of glaucoma, including RGC death induced by oxidative stress, and therefore, it is also a useful animal model for glaucoma.Edaravone is a free radical scavenger that has been used clinically to treat acute brain infarction and amyotrophic lateral sclerosis (ALS). Edaravone quenches hydroxyl radicals ( Á OH) and inhibits lipid peroxidation dependent and independent of Á OH. 12,13 In an in vitro cell culture study using the RGC-5 to study the neurobiology of RGCs, edaravone scavenged the intracellular Á OH, superoxide anion (O 2 ÀÁ ), and hydrogen peroxide (H 2 O 2 ) while demonstrating the strongest scavenging activity against14 Recent studies have shown that oxidative stress plays an important role in many ocular diseases including glaucoma. [15][16][17][18] Interestingly, edaravone attenuates retinal ischemia/reperfusion ...