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Liu Y, Xu H, Yan N, Tang Z, Wang Q. Research progress of ophthalmic preparations of immunosuppressants. Drug Deliv 2023; 30:2175925. [PMID: 36762580 DOI: 10.1080/10717544.2023.2175925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
Immune ophthalmopathy is a collection of autoimmune eye diseases. Immunosuppressants are drugs that can inhibit the body's immune response. Considering drug side effects such as hepatorenal toxicity and the unique structure of the eye, incorporating immunosuppressants into ophthalmic nanodrug delivery systems, such as microparticles, nanoparticles, liposomes, micelles, implants, and in situ gels, has the advantages of improving solubility, increasing bioavailability, high eye-target specificity, and reducing side effects. This study reviews recent research and applications of this aspect to provide a reference for the development of an ophthalmic drug delivery system.
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Affiliation(s)
- Ye Liu
- School of Pharmacy, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Haonan Xu
- School of Pharmacy, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Na Yan
- Department of Pharmacy, Jin Hua Municipal Maternal and Child Health Care Hospital, Jinhua, Zhejiang, 321000, China
| | - Zhan Tang
- School of Pharmacy, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China.,Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Qiao Wang
- School of Pharmacy, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China.,Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
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Edwards G, Olson CG, Euritt CP, Koulen P. Molecular Mechanisms Underlying the Therapeutic Role of Vitamin E in Age-Related Macular Degeneration. Front Neurosci 2022; 16:890021. [PMID: 35600628 PMCID: PMC9114494 DOI: 10.3389/fnins.2022.890021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 03/21/2022] [Indexed: 12/31/2022] Open
Abstract
The eye is particularly susceptible to oxidative stress and disruption of the delicate balance between oxygen-derived free radicals and antioxidants leading to many degenerative diseases. Attention has been called to all isoforms of vitamin E, with α-tocopherol being the most common form. Though similar in structure, each is diverse in antioxidant activity. Preclinical reports highlight vitamin E’s influence on cell physiology and survival through several signaling pathways by activating kinases and transcription factors relevant for uptake, transport, metabolism, and cellular action to promote neuroprotective effects. In the clinical setting, population-based studies on vitamin E supplementation have been inconsistent at times and follow-up studies are needed. Nonetheless, vitamin E’s health benefits outweigh the controversies. The goal of this review is to recognize the importance of vitamin E’s role in guarding against gradual central vision loss observed in age-related macular degeneration (AMD). The therapeutic role and molecular mechanisms of vitamin E’s function in the retina, clinical implications, and possible toxicity are collectively described in the present review.
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Dziedziak J, Kasarełło K, Cudnoch-Jędrzejewska A. Dietary Antioxidants in Age-Related Macular Degeneration and Glaucoma. Antioxidants (Basel) 2021; 10:antiox10111743. [PMID: 34829613 PMCID: PMC8614766 DOI: 10.3390/antiox10111743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 12/15/2022] Open
Abstract
Age-related macular degeneration (AMD) and glaucoma are ophthalmic neurodegenerative diseases responsible for irreversible vision loss in the world population. Only a few therapies can be used to slow down the progression of these diseases and there are no available treatment strategies for reversing the degeneration of the neural retina. In AMD, the pathological process causes the malfunction and damage of the retinal pigmented epithelium and photoreceptors in the macula. In glaucoma, damage of the retinal ganglion cells and their axons is observed and treatment strategies are limited to intraocular pressure lowering. Therefore, other prophylactic and/or therapeutic methods are needed. Oxidative stress is involved in the neurodegenerative process accompanying both AMD and glaucoma; therefore, the use of antioxidant agents would clearly be beneficial, which is supported by the decreased prevalence and progression of AMD in patients adherent to a diet naturally rich in antioxidants. Dietary antioxidants are easily available and their use is based on the natural route of administration. Many preclinical studies both in vitro and using animal models of retinal degeneration showed the efficacy of dietary antioxidants, which was further proved in clinical trials. Resveratrol is beneficial both in AMD and glaucoma animal models, but confirmed only among AMD patients. For AMD, carotenoids and omega-3 fatty acids were also proved to be sufficient in preventing neurodegeneration. For glaucoma, coenzyme Q10 and alpha-lipoic acid showed efficacy for decreasing retinal ganglion cell loss and inhibiting the accompanying destructive processes. Interestingly, the benefits of vitamins, especially vitamin E was not confirmed, neither in preclinical nor in clinical studies.
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Vernazza S, Oddone F, Tirendi S, Bassi AM. Risk Factors for Retinal Ganglion Cell Distress in Glaucoma and Neuroprotective Potential Intervention. Int J Mol Sci 2021; 22:7994. [PMID: 34360760 PMCID: PMC8346985 DOI: 10.3390/ijms22157994] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 12/14/2022] Open
Abstract
Retinal ganglion cells (RGCs) are a population of neurons of the central nervous system (CNS) extending with their soma to the inner retina and with their axons to the optic nerve. Glaucoma represents a group of neurodegenerative diseases where the slow progressive death of RGCs results in a permanent loss of vision. To date, although Intra Ocular Pressure (IOP) is considered the main therapeutic target, the precise mechanisms by which RGCs die in glaucoma have not yet been clarified. In fact, Primary Open Angle Glaucoma (POAG), which is the most common glaucoma form, also occurs without elevated IOP. This present review provides a summary of some pathological conditions, i.e., axonal transport blockade, glutamate excitotoxicity and changes in pro-inflammatory cytokines along the RGC projection, all involved in the glaucoma cascade. Moreover, neuro-protective therapeutic approaches, which aim to improve RGC degeneration, have also been taken into consideration.
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Affiliation(s)
- Stefania Vernazza
- Department of Experimental Medicine (DIMES), University of Genoa, 16126 Genoa, Italy; (S.T.); (A.M.B.)
| | | | - Sara Tirendi
- Department of Experimental Medicine (DIMES), University of Genoa, 16126 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Anna Maria Bassi
- Department of Experimental Medicine (DIMES), University of Genoa, 16126 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
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López-Cano JJ, Sigen A., Andrés-Guerrero V, Tai H, Bravo-Osuna I, Molina-Martínez IT, Wang W, Herrero-Vanrell R. Thermo-Responsive PLGA-PEG-PLGA Hydrogels as Novel Injectable Platforms for Neuroprotective Combined Therapies in the Treatment of Retinal Degenerative Diseases. Pharmaceutics 2021; 13:234. [PMID: 33562265 PMCID: PMC7915560 DOI: 10.3390/pharmaceutics13020234] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 12/16/2022] Open
Abstract
The present study aims to develop a thermo-responsive-injectable hydrogel (HyG) based on PLGA-PEG-PLGA (PLGA = poly-(DL-lactic acid co-glycolic acid); PEG = polyethylene glycol) to deliver neuroprotective agents to the retina over time. Two PLGA-PEG PLGA copolymers with different PEG:LA:GA ratios (1:1.54:23.1 and 1:2.25:22.5) for HyG-1 and HyG-2 development respectively were synthetized and characterized by different techniques (gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), critical micelle concentration (CMC), gelation and rheological behaviour). According to the physicochemical characterization, HyG-1 was selected for further studies and loaded with anti-inflammatory drugs: dexamethasone (0.2%), and ketorolac (0.5%), alone or in combination with the antioxidants idebenone (1 µM) and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) (0.002%). In vitro drug release and cytotoxicity studies were performed for the active substances and hydrogels (loaded and drug-free). A cellular model based on oxidative stress was optimized for anti-inflammatory and antioxidant screening of the formulations by using retinal-pigmented epithelial cell line hTERT (RPE-1). The copolymer 1, used to prepare thermo-responsive HyG-1, showed low polydispersity (PDI = 1.22) and a strong gel behaviour at 25% (w/v) in an isotonic buffer solution close to the vitreous temperature (31-34 °C). Sustained release of dexamethasone and ketorolac was achieved between 47 and 62 days, depending on the composition. HyG-1 was well tolerated (84.5 ± 3.2%) in retinal cells, with values near 100% when the anti-inflammatory and antioxidant agents were included. The combination of idebenone and dexamethasone promoted high oxidative protection in the cells exposed to H2O2, with viability values of 86.2 ± 14.7%. Ketorolac and dexamethasone-based formulations ameliorated the production of TNF-α, showing significant results (p ≤ 0.0001). The hydrogels developed in the present study entail a novel biodegradable tool to treat neurodegenerative processes of the retina overtime.
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Affiliation(s)
- José Javier López-Cano
- Research Group (UCM 920415), Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal), Complutense University, 28040 Madrid, Spain; (J.J.L.-C.); (V.A.-G.); (I.B.-O.); (I.T.M.-M.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
| | - Sigen A.
- Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin 4, Ireland; (S.A.); (W.W.)
- Blafar Ltd., Belfield Innovation Park, University College Dublin, Belfield, D04 V1W8 Dublin 4, Ireland;
| | - Vanessa Andrés-Guerrero
- Research Group (UCM 920415), Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal), Complutense University, 28040 Madrid, Spain; (J.J.L.-C.); (V.A.-G.); (I.B.-O.); (I.T.M.-M.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared), Carlos III National Institute of Health, 28029 Madrid, Spain
| | - Hongyun Tai
- Blafar Ltd., Belfield Innovation Park, University College Dublin, Belfield, D04 V1W8 Dublin 4, Ireland;
| | - Irene Bravo-Osuna
- Research Group (UCM 920415), Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal), Complutense University, 28040 Madrid, Spain; (J.J.L.-C.); (V.A.-G.); (I.B.-O.); (I.T.M.-M.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared), Carlos III National Institute of Health, 28029 Madrid, Spain
| | - Irene Teresa Molina-Martínez
- Research Group (UCM 920415), Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal), Complutense University, 28040 Madrid, Spain; (J.J.L.-C.); (V.A.-G.); (I.B.-O.); (I.T.M.-M.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared), Carlos III National Institute of Health, 28029 Madrid, Spain
| | - Wenxin Wang
- Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin 4, Ireland; (S.A.); (W.W.)
- Blafar Ltd., Belfield Innovation Park, University College Dublin, Belfield, D04 V1W8 Dublin 4, Ireland;
| | - Rocío Herrero-Vanrell
- Research Group (UCM 920415), Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal), Complutense University, 28040 Madrid, Spain; (J.J.L.-C.); (V.A.-G.); (I.B.-O.); (I.T.M.-M.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared), Carlos III National Institute of Health, 28029 Madrid, Spain
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Xu YP, Han F, Tan J. Edaravone protects the retina against ischemia/reperfusion-induced oxidative injury through the PI3K/Akt/Nrf2 pathway. Mol Med Rep 2017; 16:9210-9216. [DOI: 10.3892/mmr.2017.7739] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 05/15/2017] [Indexed: 11/06/2022] Open
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Cholkar K, Gunda S, Earla R, Pal D, Mitra AK. Nanomicellar Topical Aqueous Drop Formulation of Rapamycin for Back-of-the-Eye Delivery. AAPS PharmSciTech 2015; 16:610-22. [PMID: 25425389 DOI: 10.1208/s12249-014-0244-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/23/2014] [Indexed: 12/20/2022] Open
Abstract
The objective of this study was to develop a clear, aqueous rapamycin-loaded mixed nanomicellar formulations (MNFs) for the back-of-the-eye delivery. MNF of rapamycin (0.2%) was prepared with vitamin E tocopherol polyethylene glycol succinate (TPGS) (Vit E TPGS) and octoxynol-40 (Oc-40) as polymeric matrix. MNF was characterized by various parameters such as size, charge, shape, and viscosity. Proton nuclear magnetic resonance ((1)H NMR) was used to identify unentrapped rapamycin in MNF. Cytotoxicity was evaluated in human retinal pigment epithelial (D407) and rabbit primary corneal epithelial cells (rPCECs). In vivo posterior ocular rapamycin distribution studies were conducted in male New Zealand white rabbits. The optimized MNF has excellent rapamycin entrapment and loading efficiency. The average size of MNF was 10.98 ± 0.089 and 10.84 ± 0.11 nm for blank and rapamycin-loaded MNF, respectively. TEM analysis revealed that nanomicelles are spherical in shape. Absence of free rapamycin in the MNF was confirmed by (1)H NMR studies. Neither placebo nor rapamycin-loaded MNF produced cytotoxicity on D407 and rPCECs indicating formulations are tolerable. In vivo studies demonstrated a very high rapamycin concentration in retina-choroid (362.35 ± 56.17 ng/g tissue). No drug was identified in the vitreous humor indicating the sequestration of rapamycin in lipoidal retinal tissues. In summary, a clear, aqueous MNF comprising of Vit E TPGS and Oc-40 loaded with rapamycin was successfully developed. Back-of-the-eye tissue distribution studies demonstrated a very high rapamycin levels in retina-choroid (place of drug action) with a negligible drug partitioning into vitreous humor.
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Yazici A, Aksit H, Sari ES, Yay A, Erken HA, Aksit D, Cakmak H, Seyrek K, Ermis SS. Comparison of pre-treatment and post-treatment use of selenium in retinal ischemia reperfusion injury. Int J Ophthalmol 2015; 8:263-8. [PMID: 25938038 DOI: 10.3980/j.issn.2222-3959.2015.02.09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/27/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To investigate the effects of selenium in rat retinal ischemia reperfusion (IR) model and compare pre-treatment and post-treatment use. METHODS Selenium pre-treatment group (n=8) was treated with intraperitoneal (i.p.) selenium 0.5 mg/kg for 7d and terminated 24h after the IR injury. Selenium post-treatment group (n=8) was treated with i.p. selenium 0.5 mg/kg for 7d after the IR injury with termination at the end of the 7d period. Sham group (n=8) received i.p. saline injections identical to the selenium volume for 7d with termination 24h after the IR injury. Control group (n=8) received no intervention. Main outcome measures were retina superoxide dismutase (SOD), glutathione (GSH), total antioxidant status (TAS), malondialdehyde (MDA), DNA fragmentation levels, and immunohistological apoptosis evaluation. RESULTS Compared to the Sham group, selenium pre-treatment had a statistical difference in all parameters except SOD. Post-treatment selenium also resulted in statistical differences in all parameters except the MDA levels. When comparing selenium groups, the pre-treatment selenium group had a statistically higher success in reduction of markers of cell damage such as MDA and DNA fragmentation. In contrast, the post-selenium treatment group had resulted in statistically higher levels of GSH. Histologically both selenium groups succeeded to limit retinal thickening and apoptosis. Pre-treatment use was statistically more successful in decreasing apoptosis in ganglion cell layer compared to post-treatment use. CONCLUSION Selenium was successful in retinal protection in IR injuries. Pre-treatment efficacy was superior in terms of prevention of tissue damage and apoptosis.
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Affiliation(s)
- Alper Yazici
- Department of Ophthalmology, Faculty of Medicine, Balikesir University, Balikesir 10010, Turkey
| | - Hasan Aksit
- Department of Biochemistry, Faculty of Veterinary, Balikesir University, Balikesir 10010, Turkey
| | - Esin Sogutlu Sari
- Department of Ophthalmology, Faculty of Medicine, Balikesir University, Balikesir 10010, Turkey
| | - Arzu Yay
- Department of Histology and Embryology, Faculty of Medicine, Erciyes University, Kayseri 38010, Turkey
| | - Haydar Ali Erken
- Department of Physiology, Faculty of Medicine, Balikesir University, Balikesir 10010, Turkey
| | - Dilek Aksit
- Department of Pharmacology, Faculty of Veterinary, Balikesir University, Balikesir 10010, Turkey
| | - Harun Cakmak
- Department of Ophthalmology, Faculty of Medicine, Adnan Menderes University, Aydin 09010, Turkey
| | - Kamil Seyrek
- Department of Biochemistry, Faculty of Medicine, Balikesir University, Balikesir 10010, Turkey
| | - Sitki Samet Ermis
- Department of Ophthalmology, Faculty of Medicine, Balikesir University, Balikesir 10010, Turkey
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Yazici A, Sogutlu-Sari E, Yay A, Aksit H, Kilic A, Aksit D, Yildiz O, Ermis SS. The protective effect of selenium in cisplatin-related retinotoxicity. Cutan Ocul Toxicol 2014; 33:327-32. [DOI: 10.3109/15569527.2013.879877] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Sheng X, Fan L, He C, Zhang K, Mo X, Wang H. Vitamin E-loaded silk fibroin nanofibrous mats fabricated by green process for skin care application. Int J Biol Macromol 2013; 56:49-56. [PMID: 23396066 DOI: 10.1016/j.ijbiomac.2013.01.029] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/23/2013] [Accepted: 01/24/2013] [Indexed: 11/17/2022]
Abstract
In the present study, we reported fabrication and skin benefit of a novel vitamin E (VE)-loaded silk fibroin (SF) nanofibrous mats. RRR-α-Tocopherol polyethylene glycol 1000 succinate (VE TPGS), a water-soluble derivative of VE, was incorporated into SF nanofiber successfully by aqua solution electrospinning for the first time. Morphology of the composite nanofibers changed with the different amount of VE TPGS: a ribbon-like shape for lower loading dose of VE TPGS, while a round shape for higher loading dose (more than 4% (wt/wt) based on the weight of SF). After treated with 75% (v/v) ethanol vapor, the composite nanofibrous mats showed an excellent water-resistant ability. In vitro study disclosed a sustained release behavior of VE TPGS disassociated from the nanofibrous mats. The mouse skin fibroblasts (L929 cells) cultured on the VE-loaded SF nanofibrous mats spread and proliferated much better than on cover slips. Moreover, the incorporation of VE TPGS was found strengthening the ability of SF nanofibrous mats on protecting the cells against oxidation stress induced by tert-butyl hydroperoxide. Our data presented impressive skin benefits of this VE-loaded SF nanofibrous mats, suggesting a promising applicative potential of this novel product on personal skin care, tissue regeneration and other related area.
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Affiliation(s)
- Xiaoyue Sheng
- Biomaterials and Tissue Engineering Lab, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, PR China
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Hypoxia-induced oxidative stress in ischemic retinopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:426769. [PMID: 23125893 PMCID: PMC3483772 DOI: 10.1155/2012/426769] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/24/2012] [Accepted: 09/17/2012] [Indexed: 12/28/2022]
Abstract
Oxidative stress plays a crucial role in the pathogenesis of retinal ischemia/hypoxia, a complication of ocular diseases such as diabetic retinopathy (DR) and retinopathy of prematurity (ROP). Oxidative stress refers to the imbalance between the production of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidative systems. Free radicals and ROS are implicated in the irreversible damage to cell membrane, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Anti-oxidants that can inhibit the oxidative processes can protect retinal cells from ischemic/hypoxic insults. In particular, treatment using anti-oxidants such as vitamin E and lutein, inhibition of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) or related signaling pathways, and administration of catalase and superoxide dismutase (SOD) are possible therapeutic regimens for DR, ROP, and other retinal ischemic diseases. The role of oxidative stress in the pathogenesis of DR and ROP as well as the underlying mechanisms involved in the hypoxia/ischemia-induced oxidative damage is discussed. The information provided will be beneficial in understanding the underlying mechanisms involved in the pathogenesis of the diseases as well as in developing effective therapeutic interventions to treat oxidative stress-induced damages.
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Abstract
Retinal ischemia is a common clinical entity and, due to relatively ineffective treatment, remains a common cause of visual impairment and blindness. Generally, ischemic syndromes are initially characterized by low homeostatic responses which, with time, induce injury to the tissue due to cell loss by apoptosis. In this respect, retinal ischemia is a primary cause of neuronal death. It can be considered as a sort of final common pathway in retinal diseases and results in irreversible morphological and functional changes. This review summarizes the recent knowledge on the effects of ischemia in retinal tissue and points out experimental strategies/models performed to gain better comprehension of retinal ischemia diseases. In particular, the nature of the mechanisms leading to neuronal damage (i.e., excess of glutamate release, oxidative stress and inflammation) will be outlined as well as the potential and most intriguing retinoprotective approaches and the possible therapeutic use of naturally occurring molecules such as neuropeptides. There is a general agreement that a better understanding of the fundamental pathophysiology of retinal ischemia will lead to better management and improved clinical outcome. In this respect, to contrast this pathological state, specific pharmacological strategies need to be developed aimed at the many putative cascades generated during ischemia.
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Rosenstein RE, Pandi-Perumal SR, Srinivasan V, Spence DW, Brown GM, Cardinali DP. Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis. J Pineal Res 2010; 49:1-13. [PMID: 20492443 DOI: 10.1111/j.1600-079x.2010.00764.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several lines of evidence support the view that increased free radical generation and altered nitric oxide (NO) metabolism play a role in the pathogenesis of highly prevalent ocular diseases, such as glaucoma and uveitis. Data are discussed indicating that melatonin, being an efficient antioxidant that displays antinitridergic properties, has a promising role in the treatment of these ocular dysfunctions. Melatonin synthesis occurs in the eye of most species, and melatonin receptors are localized in different ocular structures. In view of the fact that melatonin lacks significant adverse collateral effects even at high doses, the application of melatonin could potentially protect ocular tissues by effectively scavenging free radicals and excessive amounts of NO generated in the glaucomatous or uveitic eye.
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Affiliation(s)
- Ruth E Rosenstein
- Department of Human Biochemistry, School of Medicine, CEFyBO, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
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Usoro OB, Mousa SA. Vitamin E forms in Alzheimer's disease: a review of controversial and clinical experiences. Crit Rev Food Sci Nutr 2010; 50:414-9. [PMID: 20373187 DOI: 10.1080/10408390802304222] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Vitamin E is a collective term for eight naturally occurring compounds, four tocopherols (alpha-, beta-, gamma-, and delta-) and four tocotrienols (alpha-, beta-, gamma-, and delta-). Although it is the major form of vitamin E in US diets, gamma-tocopherol receives little attention when compared to alpha-tocopherol, which is generally found in supplements and most studied for its effects on progression of cognitive impairment. Many clinical trials had been conducted with vitamin E and neurodegenerative disorders, with controversial results, including a recent study which disproves the benefit of vitamin E for Mild Cognitive Impairment and Alzheimer's Disease. This study examined the alpha-tocopherol supplement instead of gamma-tocopherol. Gamma-tocopherol has been found to be more effective in scavenging free radicals and nitrogen oxygen species that cause inflammation; both of these are components of neurodegenerative disorders. Secondly, the use of alpha-tocopherol supplements significantly reduces serum gamma-tocopherol, and this may have important biological effects. Therefore, any potential health benefits of alpha-tocopherol supplements may be offset by deleterious changes in the bioavailability of other forms of tocopherols and tocotrienols. This might account for the null effects of alpha tocopherol supplementation in Mild Cognitive Impairment and Alzheimer's Disease.
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Affiliation(s)
- Owoedimo B Usoro
- College of Pharmacy and Health Sciences, The Pharmaceutical Research Institute at the Albany, Rensselaer, NY, USA
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Lutein protects RGC-5 cells against hypoxia and oxidative stress. Int J Mol Sci 2010; 11:2109-17. [PMID: 20559505 PMCID: PMC2885097 DOI: 10.3390/ijms11052109] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 04/13/2010] [Accepted: 05/03/2010] [Indexed: 11/17/2022] Open
Abstract
Retinal ischemia and oxidative stress lead to neuronal death in many ocular pathologies. Recently, we found that lutein, an oxy-carotenoid, protected the inner retina from ischemia/reperfusion injury. However, it is uncertain whether lutein directly protects retinal ganglion cells (RGCs). Here, an in vitro model of hypoxia and oxidative stress was used to further investigate the neuroprotective role of lutein in RGCs. Cobalt chloride (CoCl2) and hydrogen peroxide (H2O2) were added to a transformed RGC cell line, RGC-5, to induce chemical hypoxia and oxidative stress, respectively. Either lutein or vehicle was added to cultured cells. A higher cell count was observed in the lutein-treated cells compared with the vehicle-treated cells. Our data from this in vitro model revealed that lutein might protect RGC-5 cells from damage when exposed to either CoCl2-induced chemical hypoxia or H2O2-induced oxidative stress. These results suggest that lutein may play a role as a neuroprotectant.
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Chu KO, Chan KP, Wang CC, Chu CY, Li WY, Choy KW, Rogers MS, Pang CP. Green tea catechins and their oxidative protection in the rat eye. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:1523-1534. [PMID: 20085274 DOI: 10.1021/jf9032602] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Catechins, active constituents of green tea, are well-known antioxidative natural products. It was proposed that green tea extract (GTE) consumption could benefit the eye, and the pharmacokinetics of catechins and oxidation status in rat eye were investigated after oral administration. Sprague-Dawley rats were fed GTE and sacrificed at different time intervals. Their eyes were dissected into cornea, lens, retina, choroid-sclera, vitreous humor, and aqueous humor for analysis of catechins and 8-epi-isoprostane by HPLC-ECD and GC-NCI-MS, respectively. Catechins were differentially distributed in eye tissues. Gallocatechin was present at the highest concentration in the retina, 22729.4 +/- 4229.4 pmol/g, and epigallocatechin in aqueous humor at 602.9 +/- 116.7 nM. The corresponding area-under-curves were 207,000 pmol x h/g and 2035.0 +/- 531.7 nM x h, respectively. The time of maximum concentration of the catechins varied from 0.5 to 12.2 h. Significant reductions in 8-epi-isoprostane levels were found in the compartments except the choroid-sclera or plasma, indicating antioxidative activities of catechins in these tissues.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong
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Cheung AKH, Lo ACY, So KF, Chung SSM, Chung SK. Gene deletion and pharmacological inhibition of aldose reductase protect against retinal ischemic injury. Exp Eye Res 2007; 85:608-16. [PMID: 17727843 DOI: 10.1016/j.exer.2007.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/16/2007] [Accepted: 07/17/2007] [Indexed: 01/26/2023]
Abstract
Retinal ischemic injury is common in patients with diabetes, atherosclerosis, hypertension, transient ischemia attack and amaurosis fugax. Previously, signs of ischemic stress, such as pericyte loss, blood-retinal barrier breakdown and neovascularization, which can lead to occlusion of retinal vessels, have been prevented in diabetic db/db mice with aldose reductase (AR) null mutation. To determine the role in retinal ischemic injury of AR and sorbitol dehydrogenase (SDH), the first and second enzymes in the polyol pathway, mice with deletion of AR (AR(-/-)) or SDH-mutation (SDH(-/-)), or C57BL/6N mice treated with AR or SDH inhibitors were subjected to transient retinal artery occlusion (2h of occlusion and 22h of reperfusion) by the intraluminal suture method. Neuronal loss and edema observed in wildtype (AR(+/+)) retinas after transient ischemia were prevented in the retinas of AR(-/-) mice or C57BL/6N mice treated with an AR inhibitor, Fidarestat. Fewer TUNEL-positive cells and smaller accumulations of nitrotyrosine and poly(ADP-ribose) were also observed in the retinas of AR(-/-) mice. However, SDH(-/-) mice and C57BL/6N mice treated with SDH inhibitor, CP-470,711, were not protected against ischemia-induced retinal damage. Taken together, AR contributes to retinal ischemic injury through increased edema and free radical accumulation. Therefore, AR inhibition should be considered for the treatment of retinal ischemic injury often observed in diabetic patients.
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Affiliation(s)
- Alvin K H Cheung
- Department of Anatomy, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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