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A Topical Formulation of Melatoninergic Compounds Exerts Strong Hypotensive and Neuroprotective Effects in a Rat Model of Hypertensive Glaucoma. Int J Mol Sci 2020; 21:ijms21239267. [PMID: 33291737 PMCID: PMC7730513 DOI: 10.3390/ijms21239267] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/23/2020] [Accepted: 12/02/2020] [Indexed: 02/08/2023] Open
Abstract
Melatonin is of great importance for regulating several eye processes, including pressure homeostasis. Melatonin in combination with agomelatine has been recently reported to reduce intraocular pressure (IOP) with higher efficacy than each compound alone. Here, we used the methylcellulose (MCE) rat model of hypertensive glaucoma, an optic neuropathy characterized by the apoptotic death of retinal ganglion cells (RGCs), to evaluate the hypotensive and neuroprotective efficacy of an eye drop nanomicellar formulation containing melatonin/agomelatine. Eye tissue distribution of melatonin/agomelatine in healthy rats was evaluated by HPLC/MS/MS. In the MCE model, we assessed by tonometry the hypotensive efficacy of melatonin/agomelatine. Neuroprotection was revealed by electroretinography; by levels of inflammatory and apoptotic markers; and by RGC density. The effects of melatonin/agomelatine were compared with those of timolol (a beta blocker with prevalent hypotensive activity) or brimonidine (an alpha 2 adrenergic agonist with potential neuroprotective efficacy), two drugs commonly used to treat glaucoma. Both melatonin and agomelatine penetrate the posterior segment of the eye. In the MCE model, IOP elevation was drastically reduced by melatonin/agomelatine with higher efficacy than that of timolol or brimonidine. Concomitantly, gliosis-related inflammation and the Bax-associated apoptosis were partially prevented, thus leading to RGC survival and recovered retinal dysfunction. We suggest that topical melatoninergic compounds might be beneficial for ocular health.
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Yadav KS, Sharma S, Londhe VY. Bio-tactics for neuroprotection of retinal ganglion cells in the treatment of glaucoma. Life Sci 2020; 243:117303. [DOI: 10.1016/j.lfs.2020.117303] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/03/2020] [Accepted: 01/12/2020] [Indexed: 01/01/2023]
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Claes M, De Groef L, Moons L. Target-Derived Neurotrophic Factor Deprivation Puts Retinal Ganglion Cells on Death Row: Cold Hard Evidence and Caveats. Int J Mol Sci 2019; 20:E4314. [PMID: 31484425 PMCID: PMC6747494 DOI: 10.3390/ijms20174314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Glaucoma and other optic neuropathies are characterized by axonal transport deficits. Axonal cargo travels back and forth between the soma and the axon terminus, a mechanism ensuring homeostasis and the viability of a neuron. An example of vital molecules in the axonal cargo are neurotrophic factors (NTFs). Hindered retrograde transport can cause a scarcity of those factors in the retina, which in turn can tilt the fate of retinal ganglion cells (RGCs) towards apoptosis. This postulation is one of the most widely recognized theories to explain RGC death in the disease progression of glaucoma and is known as the NTF deprivation theory. For several decades, research has been focused on the use of NTFs as a novel neuroprotective glaucoma treatment. Until now, results in animal models have been promising, but translation to the clinic has been highly disappointing. Are we lacking important knowledge to lever NTF therapies towards the therapeutic armamentarium? Or did we get the wrong end of the stick regarding the NTF deprivation theory? In this review, we will tackle the existing evidence and caveats advocating for and against the target-derived NTF deprivation theory in glaucoma, whilst digging into associated therapy efforts.
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Affiliation(s)
- Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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Özer MA, Erişgin Z, Özen S, Tekelioğlu Y, Takır S. Effects of intravitreous sodium hydrosulfide on intraocular pressure and retinopathy in ocular hypertensive rats. Biotech Histochem 2017; 93:8-14. [PMID: 29215307 DOI: 10.1080/10520295.2017.1373199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated the possible neuroprotectant and intraocular pressure (IOP) lowering effects of intravitreous injection of sodium hydrosulfide (NaSH) in a rodent model of experimental glaucoma. Glaucoma currently is treated by controlling IOP using medications and/or surgery. These methods are not entirely adequate for all patients. We divided 24 rats into three groups. For the control group, the right eye was treated with intravitreous saline. For the glaucoma group, ocular hypertension was induced by photocoagulating three episcleral veins and the limbal plexus of the right eye using an argon laser, then saline was injected into the vitreous of these eyes during the third week. For the NaSH group, rats were treated with intravenous NaSH 3 weeks after photocoagulation. IOP was measured each week during the 6 week experimental period. Coagulating the episcleral veins rapidly increased the IOP of rat eyes. Intravitreous injection of NaSH significantly reduced IOP. Intravitreous NaSH prevented degeneration of the retina and decreased the number of apoptotic cells. Intravitreous NaSH appeared to reduce IOP and to prevent IOP induced retinopathy in rats.
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Affiliation(s)
- M A Özer
- a Department of Ophthalmology, Section of Surgical Sciences, Faculty of Medicine , Giresun University , Giresun
| | - Z Erişgin
- b Department of Histology and Embryology, Section of Basic Sciences, Faculty of Medicine , Giresun University , Giresun
| | - S Özen
- a Department of Ophthalmology, Section of Surgical Sciences, Faculty of Medicine , Giresun University , Giresun
| | - Y Tekelioğlu
- c Department of Histology and Embryology, Section of Basic Sciences, Faculty of Medicine , Karadeniz Technical University , Trabzon
| | - S Takır
- d Department of Medical Pharmacology, Section of Internal Medicine Sciences, Faculty of Medicine , Giresun University , Giresun , Turkey
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Patil A, Singh S, Opere C, Dash A. Sustained-Release Delivery System of a Slow Hydrogen Sulfide Donor, GYY 4137, for Potential Application in Glaucoma. AAPS PharmSciTech 2017; 18:2291-2302. [PMID: 28101725 DOI: 10.1208/s12249-017-0712-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/03/2017] [Indexed: 02/03/2023] Open
Abstract
Hydrogen sulfide (H2S) targets both underlying factors in glaucoma pathogenesis by reducing elevated intraocular pressure (IOP) and providing retinal neuroprotection, whereas the current clinical approaches targets only reducing IOP. Therefore, H2S could be a potential superior candidate for glaucoma pharmacotherapy. However, H2S could be toxic in a concentration greater than 200 μM and its donors are unstable in water. Therefore, this study investigated the preparation and characterization of a non-aqueous in situ gelling sustained-release delivery system for H2S donors. The delivery system was prepared by dissolving GYY 4137, a H2S donor, in poly lactide-co-glycolide polymer (PLGA) (Resomer® RG 502H) solution prepared by dissolving polymer in a mixture of benzyl alcohol and benzyl benzoate in a ratio of 7:3, respectively. The GYY 4137 formulation was characterized for syringeability/injectability, change in pH and tonicity, moisture content, GYY 4137 degradation, and toxicity using rheometer, pH and osmometer, Karl Fisher titrimeter, NMR spectrometer, and Y79 retinoblastoma cells, respectively. The formulation was easily syringeable and injectable as evidenced by rheological data (plastic flow pattern with 43.89 ± 3.21 cP viscosity and 1.12 ± 0.15 Pa yield value). The pH, tonicity, and moisture content values were within acceptable range. NMR spectroscopy indicated presence of 4-methoxyphenylphosphonic acid (GYY 4137 degradation product). The GYY 4137 formulation did not show any significant (p < 0.05) toxicity except the solvent mixture. A sustained release of H2S was observed up to 72 h. The in situ gel forming PLGA-based system can be manipulated to achieve sustained release of H2S from its donor GYY 4137.
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Donegan RK, Lieberman RL. Discovery of Molecular Therapeutics for Glaucoma: Challenges, Successes, and Promising Directions. J Med Chem 2016; 59:788-809. [PMID: 26356532 PMCID: PMC5547565 DOI: 10.1021/acs.jmedchem.5b00828] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glaucoma, a heterogeneous ocular disorder affecting ∼60 million people worldwide, is characterized by painless neurodegeneration of retinal ganglion cells (RGCs), resulting in irreversible vision loss. Available therapies, which decrease the common causal risk factor of elevated intraocular pressure, delay, but cannot prevent, RGC death and blindness. Notably, it is changes in the anterior segment of the eye, particularly in the drainage of aqueous humor fluid, which are believed to bring about changes in pressure. Thus, it is primarily this region whose properties are manipulated in current and emerging therapies for glaucoma. Here, we focus on the challenges associated with developing treatments, review the available experimental methods to evaluate the therapeutic potential of new drugs, describe the development and evaluation of emerging Rho-kinase inhibitors and adenosine receptor ligands that offer the potential to improve aqueous humor outflow and protect RGCs simultaneously, and present new targets and approaches on the horizon.
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Affiliation(s)
- Rebecca K Donegan
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, United States
| | - Raquel L Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, United States
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Galvao J, Elvas F, Martins T, Cordeiro MF, Ambrósio AF, Santiago AR. Adenosine A3 receptor activation is neuroprotective against retinal neurodegeneration. Exp Eye Res 2015; 140:65-74. [PMID: 26297614 DOI: 10.1016/j.exer.2015.08.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 08/05/2015] [Accepted: 08/12/2015] [Indexed: 12/27/2022]
Abstract
Death of retinal neural cells, namely retinal ganglion cells (RGCs), is a characteristic of several retinal neurodegenerative diseases. Although the role of adenosine A3 receptor (A3R) in neuroprotection is controversial, A3R activation has been reported to afford protection against several brain insults, with few studies in the retina. In vitro models (retinal neural and organotypic cultures) and animal models [ischemia-reperfusion (I-R) and partial optic nerve transection (pONT)] were used to study the neuroprotective properties of A3R activation against retinal neurodegeneration. The A3R selective agonist (2-Cl-IB-MECA, 1 μM) prevented apoptosis (TUNEL(+)-cells) induced by kainate and cyclothiazide (KA + CTZ) in retinal neural cultures (86.5 ± 7.4 and 37.2 ± 6.1 TUNEL(+)-cells/field, in KA + CTZ and KA + CTZ + 2-Cl-IB-MECA, respectively). In retinal organotypic cultures, 2-Cl-IB-MECA attenuated NMDA-induced cell death, assessed by TUNEL (17.3 ± 2.3 and 8.3 ± 1.2 TUNEL(+)-cells/mm(2) in NMDA and NMDA+2-Cl-IB-MECA, respectively) and PI incorporation (ratio DIV4/DIV2 3.3 ± 0.3 and 1.3 ± 0.1 in NMDA and NMDA+2-Cl-IB-MECA, respectively) assays. Intravitreal 2-Cl-IB-MECA administration afforded protection against I-R injury decreasing the number of TUNEL(+) cells by 72%, and increased RGC survival by 57%. Also, intravitreal administration of 2-Cl-IB-MECA inhibited apoptosis (from 449.4 ± 37.8 to 207.6 ± 48.9 annexin-V(+)-cells) and RGC loss (from 1.2 ± 0.6 to 8.1 ± 1.7 cells/mm) induced by pONT. This study demonstrates that 2-Cl-IB-MECA is neuroprotective to the retina, both in vitro and in vivo. Activation of A3R may have great potential in the management of retinal neurodegenerative diseases characterized by RGC death, as glaucoma and diabetic retinopathy, and ischemic diseases.
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Affiliation(s)
- Joana Galvao
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Glaucoma & Retinal Neurodegeneration Research Group, University College London, London EC1V 9EL, UK.
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light (AIBILI), Coimbra 3000-548, Portugal.
| | - Tiago Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light (AIBILI), Coimbra 3000-548, Portugal.
| | - M Francesca Cordeiro
- Glaucoma & Retinal Neurodegeneration Research Group, University College London, London EC1V 9EL, UK; Western Eye Hospital, Imperial College, London, UK.
| | - António Francisco Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light (AIBILI), Coimbra 3000-548, Portugal; CNC.IBILI, University of Coimbra, 3004-517 Coimbra, Portugal.
| | - Ana Raquel Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light (AIBILI), Coimbra 3000-548, Portugal; CNC.IBILI, University of Coimbra, 3004-517 Coimbra, Portugal.
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Cordeiro MF, Levin LA. Clinical evidence for neuroprotection in glaucoma. Am J Ophthalmol 2011; 152:715-6. [PMID: 22017839 DOI: 10.1016/j.ajo.2011.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/12/2011] [Accepted: 06/14/2011] [Indexed: 10/16/2022]
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