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Li J, Zhou W, Liang L, Li Y, Xu K, Li X, Huang Z, Jin Y. Noninvasive electrical stimulation as a neuroprotective strategy in retinal diseases: a systematic review of preclinical studies. J Transl Med 2024; 22:28. [PMID: 38184580 PMCID: PMC10770974 DOI: 10.1186/s12967-023-04766-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/27/2023] [Indexed: 01/08/2024] Open
Abstract
BACKGROUND Electrical activity has a crucial impact on the development and survival of neurons. Numerous recent studies have shown that noninvasive electrical stimulation (NES) has neuroprotective action in various retinal disorders. OBJECTIVE To systematically review the literature on in vivo studies and provide a comprehensive summary of the neuroprotective action and the mechanisms of NES on retinal disorders. METHODS Based on the PRISMA guideline, a systematic review was conducted in PubMed, Web of Science, Embase, Scopus and Cochrane Library to collect all relevant in vivo studies on "the role of NES on retinal diseases" published up until September 2023. Possible biases were identified with the adopted SYRCLE's tool. RESULTS Of the 791 initially gathered studies, 21 articles met inclusion/exclusion criteria for full-text review. The results revealed the neuroprotective effect of NES (involved whole-eye, transcorneal, transscleral, transpalpebral, transorbital electrical stimulation) on different retinal diseases, including retinitis pigmentosa, retinal degeneration, high-intraocular pressure injury, traumatic optic neuropathy, nonarteritic ischemic optic neuropathy. NES could effectively delay degeneration and apoptosis of retinal neurons, preserve retinal structure and visual function with high security, and its mechanism of action might be related to promoting the secretion of neurotrophins and growth factors, decreasing inflammation, inhibiting apoptosis. The quality scores of included studies ranged from 5 to 8 points (a total of 10 points), according to SYRCLE's risk of bias tool. CONCLUSION This systematic review indicated that NES exerts neuroprotective effects on retinal disease models mainly through its neurotrophic, anti-inflammatory, and anti-apoptotic capabilities. To assess the efficacy of NES in a therapeutic setting, however, well-designed clinical trials are required in the future.
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Affiliation(s)
- Jiaxian Li
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Wei Zhou
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Lina Liang
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China.
| | - Yamin Li
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Kai Xu
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Xiaoyu Li
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Ziyang Huang
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
| | - Yu Jin
- Department of Eye Function Laboratory, Eye Hospital, China Academy of Chinese Medical Sciences, 33 Lugu Road, Shijingshan District, Beijing, 100040, People's Republic of China
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Navarro PA, Contreras-Lopez WO, Tello A, Cardenas PL, Vargas MD, Martinez LC, Yepes-Nuñez JJ. Effectiveness and Safety of Non-Invasive Neuromodulation for Vision Restoration: A Systematic Review and Meta-Analysis. Neuroophthalmology 2023; 48:93-110. [PMID: 38487361 PMCID: PMC10936670 DOI: 10.1080/01658107.2023.2279092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/23/2023] [Indexed: 03/17/2024] Open
Abstract
We carried out a systematic review and meta-analysis to determine the effectiveness and safety of non-invasive electrical stimulation (NES) for vision restoration. We systematically searched for randomised controlled trials (RCTs) comparing NES with sham stimulation, for vision restoration between 2000 and 2022 in CENTRAL, MEDLINE, EMBASE, and LILACS. The main outcomes were as follows: visual acuity (VA); detection accuracy; foveal threshold; mean sensitivity as the parameter for the visual field; reading performance; contrast sensitivity (CS); electroencephalogram; quality of life (QoL), and safety. Two reviewers independently selected studies, extracted data, and evaluated the risk of bias using the Cochrane risk of bias 2.0 tool. The certainty in the evidence was determined using the GRADE framework. Protocol registration: CRD42022329342. Thirteen RCTs involving 441 patients with vision impairment indicate that NES may improve VA in the immediate post-intervention period (mean difference [MD] = -0.02 logMAR, 95% confidence intervals [CI] -0.08 to 0.04; low certainty), and probably increases QoL and detection accuracy (MD = 0.08, 95% CI -0.25 to 0.42 and standardised MD [SMD] = 0.09, 95% CI -0.58 to 0.77, respectively; both moderate certainty). NES likely results in little or no difference in mean sensitivity (SMD = -0.03, 95% CI -0.53 to 0.48). Compared with sham stimulation, NES increases the risk of minor adverse effects (risk ratio = 1.24, 95% CI 0.99 to 1.54; moderate certainty). The effect of NES on CS, reading performance, and electroencephalogram was uncertain. Our study suggests that although NES may slightly improve VA, detection accuracy, and QoL, the clinical relevance of these findings remains uncertain. Future research should focus on improving the available evidence's precision and consistency.
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Affiliation(s)
| | - William Omar Contreras-Lopez
- Departament of Neuromodulation, NEMOD Research Group, Bucaramanga, Colombia
- Department of Neurosurgery, Fundación Oftalmológica de Santander FOSCAL, Floridablanca, Colombia
- School of Medicine, Department of Ophthalmology, Universidad Autonoma de Bucaramanga (UNAB), Bucaramanga, Colombia
| | - Alejandro Tello
- School of Medicine, Department of Ophthalmology, Universidad Autonoma de Bucaramanga (UNAB), Bucaramanga, Colombia
- Department of Neuro-Ophthalmology, Centro Oftalmológico Virgilio Galvis, Floridablanca, Colombia
- Department of Ophthalmology, Fundación Oftalmológica de Santander FOSCAL, Floridablanca, Colombia
- School of Medicine, Department of Ophthalmology, Universidad Industrial de Santander (UIS), Bucaramanga, Colombia
| | - Pedro Luis Cardenas
- School of Medicine, Department of Ophthalmology, Universidad Autonoma de Bucaramanga (UNAB), Bucaramanga, Colombia
- Department of Neuro-Ophthalmology, Centro Oftalmológico Virgilio Galvis, Floridablanca, Colombia
- Department of Ophthalmology, Fundación Oftalmológica de Santander FOSCAL, Floridablanca, Colombia
- School of Medicine, Department of Ophthalmology, Universidad Industrial de Santander (UIS), Bucaramanga, Colombia
| | | | - Luz Catherine Martinez
- School of Medicine, Department of Ophthalmology, Universidad Autonoma de Bucaramanga (UNAB), Bucaramanga, Colombia
- Department of Ophthalmology, Fundación Oftalmológica de Santander FOSCAL, Floridablanca, Colombia
| | - Juan José Yepes-Nuñez
- School of Medicine, Universidad de los Andes, Bogotá DC, Colombia
- Department of Epidemiology, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá DC, Colombia
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Lin JC, Song SL, Ng SM, Scott IU, Greenberg PB. Treatments for Acute Nonarteritic Central Retinal Artery Occlusion: Findings From a Cochrane Systematic Review. Ophthalmic Surg Lasers Imaging Retina 2023; 54:650-653. [PMID: 37855834 DOI: 10.3928/23258160-20230922-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Many interventions for nonarteritic central retinal artery occlusion (CRAO) are associated with serious complications and little effect on visual outcomes. We report on the findings of a Cochrane systematic review that searched seven databases for peer-reviewed articles reporting on treatments for acute nonarteritic CRAO. We assessed six randomized controlled trials, including interventions such as tissue plasminogen activator (t-PA), isovolumic hemodilution, eyeball massage, intraocular pressure reduction, anticoagulation, vasodilation, oxygen inhalation, laser embolysis, transcorneal electrical stimulation, thrombolysis, pentoxifylline, and enhanced external counterpulsation. However, none of the randomized controlled trials demonstrated significant improvement in visual acuity at 1 month compared to observation, and some patients treated with t-PA experienced serious adverse effects including intracranial hemorrhage. Proposed interventions for acute nonarteritic CRAO may not be better than observation, but the evidence is uncertain. Larger, well-designed studies are necessary to determine the most effective management option for acute nonarteritic CRAO. [Ophthalmic Surg Lasers Imaging Retina 2023;54:650-653.].
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Miura G, Fujiwara T, Ozawa Y, Shiko Y, Kawasaki Y, Nizawa T, Tatsumi T, Kurimoto T, Mori S, Nakamura M, Hanaoka H, Baba T, Yamamoto S. Efficacy and safety of transdermal electrical stimulation in patients with nonarteritic anterior ischemic optic neuropathy. Bioelectron Med 2023; 9:22. [PMID: 37876021 PMCID: PMC10598888 DOI: 10.1186/s42234-023-00125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/12/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND No effective treatment for NAION with strong evidence has been established till date. The aim of this investigator-led, prospective, non-randomized, open-label, uncontrolled multi-center exploratory clinical trial is to evaluate the efficacy and safety of transdermal electrical stimulation (TdES) using skin electrodes in patients with NAION. METHODS Five patients with monocular NAION underwent TdES (10-ms biphasic pulses, 1.0 mA, 20 Hz, 30 min) of the affected eye six times at 2-week intervals. The primary endpoint was the logarithm of the mini-mum angle of resolution (logMAR) visual acuity at 12 weeks compared with 0 weeks. The secondary endpoints were changes in the best-corrected logMAR visual acuity, Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity, and mean deviation (MD) of the Humphrey field analyzer (HFA) 10-2 and HFA Esterman test scores. Additionally, the safety of TdES was evaluated. RESULTS LogMAR visual acuity improved by ≥ 0.1 in two eyes, and ETDRS visual acu-ity improved by ≥ 5 characters in one eye. The mean change in logMAR visual acuity from week 0 showed an increasing trend. The mean MD of HFA 10-2 showed no obvious change, while HFA Esterman score improved in four eyes. All patients completed the study according to the protocol, and no treatment-related adverse events were observed. CONCLUSIONS TdES treatment may have improved visual acuity and visual field in some patients. Further sham-controlled study in larger cohort is needed on its effectiveness. TRIAL REGISTRATION UMIN, UMIN000036220. Registered 15 March, 2019, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000041261 .
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Affiliation(s)
- Gen Miura
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba, 260-8670, Japan.
| | - Tadami Fujiwara
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yoshihito Ozawa
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yuki Shiko
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yohei Kawasaki
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Tomohiro Nizawa
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba, 260-8670, Japan
| | - Tomoaki Tatsumi
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba, 260-8670, Japan
| | - Takuji Kurimoto
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Sotaro Mori
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Makoto Nakamura
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Hideki Hanaoka
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Takayuki Baba
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba, 260-8670, Japan
| | - Shuichi Yamamoto
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba, 260-8670, Japan
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Sharif NA. Electrical, Electromagnetic, Ultrasound Wave Therapies, and Electronic Implants for Neuronal Rejuvenation, Neuroprotection, Axonal Regeneration, and IOP Reduction. J Ocul Pharmacol Ther 2023; 39:477-498. [PMID: 36126293 DOI: 10.1089/jop.2022.0046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The peripheral nervous system (PNS) of mammals and nervous systems of lower organisms possess significant regenerative potential. In contrast, although neural plasticity can provide some compensation, the central nervous system (CNS) neurons and nerves of adult mammals generally fail to regenerate after an injury or damage. However, use of diverse electrical, electromagnetic and sonographic energy waves are illuminating novel ways to stimulate neuronal differentiation, proliferation, neurite growth, and axonal elongation/regeneration leading to various levels of functional recovery in animals and humans afflicted with disorders of the CNS, PNS, retina, and optic nerve. Tools such as acupuncture, electroacupuncture, electroshock therapy, electrical stimulation, transcranial magnetic stimulation, red light therapy, and low-intensity pulsed ultrasound therapy are demonstrating efficacy in treating many different maladies. These include wound healing, partial recovery from motor dysfunctions, recovery from ischemic/reperfusion insults and CNS and ocular remyelination, retinal ganglion cell (RGC) rejuvenation, and RGC axonal regeneration. Neural rejuvenation and axonal growth/regeneration processes involve activation or intensifying of the intrinsic bioelectric waves (action potentials) that exist in every neuronal circuit of the body. In addition, reparative factors released at the nerve terminals and via neuronal dendrites (transmitter substances), extracellular vesicles containing microRNAs and neurotrophins, and intercellular communication occurring via nanotubes aid in reestablishing lost or damaged connections between the traumatized tissues and the PNS and CNS. Many other beneficial effects of the aforementioned treatment paradigms are mediated via gene expression alterations such as downregulation of inflammatory and death-signal genes and upregulation of neuroprotective and cytoprotective genes. These varied techniques and technologies will be described and discussed covering cell-based and animal model-based studies. Data from clinical applications and linkage to human ocular diseases will also be discussed where relevant translational research has been reported.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, California, USA
- Singapore Eye Research Institute (SERI), Singapore
- SingHealth Duke-NUS Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-National University of Singapore Medical School, Singapore
- Department of Surgery and Cancer, Imperial College of Science and Technology, London, United Kingdom
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, Texas, USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA
- Department of Pharmacy Sciences, Creighton University, Omaha, Nebraska, USA
- Insitute of Ophthalmology, University College London (UCL), London, United Kingdom
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Ashok A, Tai WL, Lennikov A, Chang K, Chen J, Li B, Cho KS, Utheim TP, Chen DF. Electrical stimulation alters DNA methylation and promotes neurite outgrowth. J Cell Biochem 2023; 124:1530-1545. [PMID: 37642194 DOI: 10.1002/jcb.30462] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023]
Abstract
Electrical stimulation (ES) influences neural regeneration and functionality. We here investigate whether ES regulates DNA demethylation, a critical epigenetic event known to influence nerve regeneration. Retinal ganglion cells (RGCs) have long served as a standard model for central nervous system neurons, whose growth and disease development are reportedly affected by DNA methylation. The current study focuses on the ability of ES to rescue RGCs and preserve vision by modulating DNA demethylation. To evaluate DNA demethylation pattern during development, RGCs from mice at different stages of development, were analyzed using qPCR for ten-eleven translocation (TETs) and immunostained for 5 hydroxymethylcytosine (5hmc) and 5 methylcytosine (5mc). To understand the effect of ES on neurite outgrowth and DNA demethylation, cells were subjected to ES at 75 µAmp biphasic ramp for 20 min and cultured for 5 days. ES increased TETs mediated neurite outgrowth, DNA demethylation, TET1 and growth associated protein 43 levels significantly. Immunostaining of PC12 cells following ES for histone 3 lysine 9 trimethylation showed cells attained an antiheterochromatin configuration. Cultured mouse and human retinal explants stained with β-III tubulin exhibited increased neurite growth following ES. Finally, mice subjected to optic nerve crush injury followed by ES exhibited improved RGCs function and phenotype as validated using electroretinogram and immunohistochemistry. Our results point to a possible therapeutic regulation of DNA demethylation by ES in neurons.
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Affiliation(s)
- Ajay Ashok
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Wai Lydia Tai
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Anton Lennikov
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Karen Chang
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Julie Chen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Boyuan Li
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
| | - Kin-Sang Cho
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Tor Paaske Utheim
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
| | - Dong Feng Chen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
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Lin JC, Song S, Ng SM, Scott IU, Greenberg PB. Interventions for acute non-arteritic central retinal artery occlusion. Cochrane Database Syst Rev 2023; 1:CD001989. [PMID: 36715340 PMCID: PMC9885744 DOI: 10.1002/14651858.cd001989.pub3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Acute non-arteritic central retinal artery occlusion (CRAO) occurs as a sudden interruption of the blood supply to the retina and typically results in severe loss of vision in the affected eye. Although many therapeutic interventions have been proposed, there is no generally agreed upon treatment regimen. OBJECTIVES To assess the effects of treatments for acute non-arteritic CRAO. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2022, Issue 2); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 15 February 2022. SELECTION CRITERIA We included randomized controlled trials (RCTs) comparing any interventions with another treatment in participants with acute non-arteritic CRAO in one or both eyes. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology and graded the certainty of the body of evidence for primary (mean change in best-corrected visual acuity [BCVA]) and secondary (quality of life and adverse events) outcomes using the GRADE classification. MAIN RESULTS We included six RCTs with 223 total participants with acute non-arteritic CRAO; the studies ranged in size from 10 to 84 participants. The included studies varied geographically: one in Australia, one in Austria and Germany, two in China, one in Germany, and one in Italy. We were unable to conduct any meta-analyses due to study heterogeneity. None of the included studies compared the same pair of interventions: 1) tissue plasminogen activator (t-PA) versus intravenous saline; 2) t-PA versus isovolemic hemodilution, eyeball massage, intraocular pressure reduction, and anticoagulation; 3) nitroglycerin, methazolamide, mecobalamin tablets, vitamin B1 and B12 injections, puerarin and compound anisodine (also known as 654-2) along with oxygen inhalation, eyeball massage, tube expansion, and anticoagulation compared with and without intravenous recombinant tissue plasminogen activator (rt-PA); 4) transcorneal electrical stimulation (TES) with 0 mA versus with 66% of the participant's individual electrical phosphene threshold (EPT) at 20 Hz (66%) versus with 150% of the participant's individual EPT (150%) at 20 Hz; 5) ophthalmic artery branch retrograde thrombolysis versus superselective ophthalmic artery thrombolysis; and 6) pentoxifylline versus placebo. There was no evidence of an important difference in visual acuity between participants treated with t-PA versus intravenous saline (mean difference [MD] at 1 month -0.15 logMAR, 95% confidence interval [CI] -0.48 to 0.18; 1 study, 16 participants; low certainty evidence); t-PA versus isovolemic hemodilution, eyeball massage, intraocular pressure reduction, and anticoagulation (MD at 1 month -0.00 logMAR, 95% CI -0.24 to 0.23; 1 study, 82 participants; low certainty evidence); and TES with 0 mA versus TES with 66% of EPT at 20 Hz versus TES with 150% of EPT at 20 Hz. Participants treated with t-PA experienced higher rates of serious adverse effects. The other three comparisons did not report statistically significant differences. Other studies reported no data on secondary outcomes (quality of life or adverse events). AUTHORS' CONCLUSIONS: The current research suggests that proposed interventions for acute non-arteritic CRAO may not be better than observation or treatments of any kind such as eyeball massage, oxygen inhalation, tube expansion, and anticoagulation, but the evidence is uncertain. Large, well-designed RCTs are necessary to determine the most effective treatment for acute non-arteritic CRAO.
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Affiliation(s)
- John C Lin
- Division of Ophthalmology, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Sophia Song
- Division of Ophthalmology, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Sueko M Ng
- Department of Ophthalmology, University of Colorado Denver - Anschutz Medical Campus, Aurora, Colorado, USA
| | - Ingrid U Scott
- Departments of Ophthalmology and Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Paul B Greenberg
- Section of Ophthalmology, VA Medical Center, Providence, Rhode Island, USA
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Agadagba SK, Lim LW, Chan LLH. Advances in transcorneal electrical stimulation: From the eye to the brain. Front Cell Neurosci 2023; 17:1134857. [PMID: 36937185 PMCID: PMC10019785 DOI: 10.3389/fncel.2023.1134857] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 02/07/2023] [Indexed: 03/06/2023] Open
Abstract
The mammalian brain is reported to contain about 106-109 neurons linked together to form complex networks. Physiologically, the neuronal networks interact in a rhythmic oscillatory pattern to coordinate the brain's functions. Neuromodulation covers a broad range of techniques that can alter neuronal network activity through the targeted delivery of electrical or chemical stimuli. Neuromodulation can be used to potentially treat medical conditions and can serve as a research tool for studying neural functions. Typically, the main method of neuromodulation is to electrically stimulate specific structures in both the central and peripheral nervous systems via surgically implanted electrodes. Therefore, it is imperative to explore novel and safer methods for altering neuronal network activity. Transcorneal electrical stimulation (TES) has rapidly emerged as a non-invasive neuromodulatory technique that can exert beneficial effects on the brain through the eyes. There is substantial evidence to show that TES can change the brain oscillations in rodents. Moreover, the molecular data clearly shows that TES can also activate non-visual brain regions. In this review, we first summarize the use of TES in the retina and then discuss its effects in the brain through the eye-brain connection. We then comprehensively review the substantial evidence from electrophysiological, behavioral, and molecular studies on the role of TES on modulating neurons in the brain. Lastly, we discuss the implications and possible future directions of the research on TES as a non-invasive tool for neuromodulation of the brain via directly stimulating the mammalian eye.
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Affiliation(s)
| | - Lee Wei Lim
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
- *Correspondence: Leanne Lai Hang Chan
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Miura G, Fujiwara T, Iwase T, Ozawa Y, Shiko Y, Kawasaki Y, Nizawa T, Tatsumi T, Baba T, Kurimoto T, Mori S, Nakamura M, Hanaoka H, Yamamoto S. Exploratory clinical trial to evaluate the efficacy and safety of transdermal electrical stimulation in patients with central retinal artery occlusion. PLoS One 2023; 18:e0282003. [PMID: 36827287 PMCID: PMC9955643 DOI: 10.1371/journal.pone.0282003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 01/30/2023] [Indexed: 02/25/2023] Open
Abstract
PURPOSE To evaluate the efficacy and safety of transdermal electrical stimulation (TdES) using skin electrodes in patients with central retinal artery occlusion (CRAO). METHODS Five eyes of five patients with CRAO underwent TdES (10-ms biphasic pulses, 20 Hz, 30 min) six times at 2-week intervals. Only the affected eye was stimulated with 1.0-mA pulses in all patients. The primary endpoint was the best-corrected logMAR visual acuity. The secondary endpoints were changes in the best-corrected logMAR visual acuity, Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity, mean deviation of the Humphrey field analyzer (HFA) 10-2, and HFA Esterman test score. We also evaluated its safety. RESULTS The logMAR visual acuity at 12 weeks was improved by 0.1 or more in two patients and was maintained in two patients compared to the baseline. No obvious changes in the mean logMAR visual acuity, ETDRS visual acuity, mean deviation, and HFA Esterman score were observed at 12 weeks compared to the baseline. All five enrolled patients completed the study according to the protocol. No treatment-related adverse events were observed during this study. CONCLUSION In this study, logMAR visual acuity was slightly improved in two patients, confirming the safety of TdES. Since CRAO has no established treatment method, further research into the effects of TdES treatment in CRAO patients may be beneficial.
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Affiliation(s)
- Gen Miura
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
- * E-mail:
| | - Tadami Fujiwara
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Takayuki Iwase
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yoshihito Ozawa
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yuki Shiko
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Yohei Kawasaki
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Tomohiro Nizawa
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Tomoaki Tatsumi
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takayuki Baba
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takuji Kurimoto
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sotaro Mori
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Makoto Nakamura
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hideki Hanaoka
- Clinical Research Centre, Chiba University Hospital, Chiba, Japan
| | - Shuichi Yamamoto
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
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10
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Yang M, Lennikov A, Chang K, Ashok A, Lee C, Cho KS, Utheim TP, Dartt DA, Chen DF. Transcorneal but not transpalpebral electrical stimulation disrupts mucin homeostasis of the ocular surface. BMC Ophthalmol 2022; 22:490. [PMID: 36522696 PMCID: PMC9756492 DOI: 10.1186/s12886-022-02717-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Transcorneal electrical stimulation (TcES) is increasingly applied as a therapy for preserving and improving vision in retinal neurodegenerative and ischemic disorders. However, a common complaint about TcES is its induction of eye pain and dryness in the clinic, while the mechanisms remain unknown. METHOD TcES or transpalpebral ES (TpES) was conducted in C57BL6j mice for 14 days. The contralateral eyes were used as non-stimulated controls. Levels of intracellular [Ca2+] ([Ca2+]i) were assessed by Fura-2AM. The conductance resistances of the eye under various ES conditions were measured in vivo by an oscilloscope. RESULTS Although TcES did not affect tear production, it significantly induced damage to the ocular surface, as revealed by corneal fluorescein staining that was accompanied by significantly decreased mucin (MUC) 4 expression compared to the control. Similar effects of ES were detected in cultured primary corneal epithelium cells, showing decreased MUC4 and ZO-1 levels after the ES in vitro. In addition, TcES decreased secretion of MUC5AC from the conjunctiva in vivo, which was also corroborated in goblet cell cultures, where ES significantly attenuated carbachol-induced [Ca2+]i increase. In contrast to TcES, transpalpebral ES (TpES) did not induce corneal fluorescein staining while significantly increasing tear production. Importantly, the conductive resistance from orbital skin to the TpES was significantly smaller than that from the cornea to the retina in TcES. CONCLUSION TcES, but not TpES, induces corneal epithelial damage in mice by disrupting mucin homeostasis. TpES thus may represent a safer and more effective ES approach for treating retinal neurodegeneration clinically.
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Affiliation(s)
- Menglu Yang
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA
| | - Anton Lennikov
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA ,grid.5510.10000 0004 1936 8921Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Kirkeveien 166, Oslo, 0450 Norway
| | - Karen Chang
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA ,grid.5510.10000 0004 1936 8921Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Kirkeveien 166, Oslo, 0450 Norway
| | - Ajay Ashok
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA ,grid.5510.10000 0004 1936 8921Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Kirkeveien 166, Oslo, 0450 Norway
| | - Cherin Lee
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA
| | - Kin-Sang Cho
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA
| | - Tor Paaske Utheim
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA ,grid.5510.10000 0004 1936 8921Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Kirkeveien 166, Oslo, 0450 Norway
| | - Darlene A. Dartt
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA
| | - Dong Feng Chen
- grid.38142.3c000000041936754XDepartment of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, 20 Staniford St, Boston, MA 02114 USA
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11
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Lennikov A, Yang M, Chang K, Pan L, Saddala MS, Lee C, Ashok A, Cho KS, Utheim TP, Chen DF. Direct modulation of microglial function by electrical field. Front Cell Dev Biol 2022; 10:980775. [PMID: 36158207 PMCID: PMC9493490 DOI: 10.3389/fcell.2022.980775] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/03/2022] [Indexed: 12/03/2022] Open
Abstract
Non-invasive electric stimulation (ES) employing a low-intensity electric current presents a potential therapeutic modality that can be applied for treating retinal and brain neurodegenerative disorders. As neurons are known to respond directly to ES, the effects of ES on glia cells are poorly studied. A key question is if ES directly mediates microglial function or modulates their activity merely via neuron-glial signaling. Here, we demonstrated the direct effects of ES on microglia in the BV-2 cells—an immortalized murine microglial cell line. The low current ES in a biphasic ramp waveform, but not that of rectangular or sine waveforms, significantly suppressed the motility and migration of BV-2 microglia in culture without causing cytotoxicity. This was associated with diminished cytoskeleton reorganization and microvilli formation in BV-2 cultures, as demonstrated by immunostaining of cytoskeletal proteins, F-actin and β-tubulin, and scanning electron microscopy. Moreover, ES of a ramp waveform reduced microglial phagocytosis of fluorescent zymosan particles and suppressed lipopolysaccharide (LPS)-induced pro-inflammatory cytokine expression in BV-2 cells as shown by Proteome Profiler Mouse Cytokine Array. The results of quantitative PCR and immunostaining for cyclooxygenase-2, Interleukin 6, and Tumor Necrosis Factor-α corroborated the direct suppression of LPS-induced microglial responses by a ramp ES. Transcriptome profiling further demonstrated that ramp ES effectively suppressed nearly half of the LPS-induced genes, primarily relating to cellular motility, energy metabolism, and calcium signaling. Our results reveal a direct modulatory effect of ES on previously thought electrically “non-responsive” microglia and suggest a new avenue of employing ES for anti-inflammatory therapy.
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Affiliation(s)
- Anton Lennikov
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Menglu Yang
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
| | - Karen Chang
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Li Pan
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China
| | - Madhu Sudhana Saddala
- Wilmer Bioinformatics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Cherin Lee
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
| | - Ajay Ashok
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Kin-Sang Cho
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
| | - Tor Paaske Utheim
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Dong Feng Chen
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA, United States
- *Correspondence: Dong Feng Chen,
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12
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Lu Z, Zhou M, Guo T, Liang J, Wu W, Gao Q, Li L, Li H, Chai X. An in-silico analysis of retinal electric field distribution induced by different electrode design of trans-corneal electrical stimulation. J Neural Eng 2022; 19. [PMID: 36044887 DOI: 10.1088/1741-2552/ac8e32] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/31/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Trans-corneal electrical stimulation (TcES) produces therapeutic effects on many ophthalmic diseases non-invasively. Existing clinical TcES devices use largely variable design of electrode distribution and stimulation parameters. Better understanding of how electrode configuration paradigms and stimulation parameters influence the electric field distribution on the retina, will be beneficial to the design of next-generation TcES devices. APPROACH In this study, we constructed a realistic finite element human head model with fine eyeball structure. Commonly used DTL-Plus and ERG-Jet electrodes were simulated. We then conducted in silico investigations of retina observation surface (ROS) electric field distributions induced by different return electrode configuration paradigms and different stimulus intensities. MAIN RESULTS Our results suggested that the ROS electric field distribution could be modulated by re-designing TcES electrode settings and stimulus parameters. Under far return location (FRL) paradigms, either DTL-Plus or ERG-Jet approach could induce almost identical ROS electric field distribution regardless where the far return was located. However, compared with the ERG-Jet mode, DTL-Plus stimulation induced stronger nasal lateralization. In contrast, ERG-Jet stimulation induced relatively stronger temporal lateralization. The ROS lateralization can be further tweaked by changing the DTL-Plus electrode length. SIGNIFICANCE These results may contribute to the understanding of the characteristics of DTL-Plus and ERG-Jet electrodes based electric field distribution on the retina, providing practical implications for the therapeutic application of TcES.
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Affiliation(s)
- Zhuofan Lu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai, Shanghai, 200240, CHINA
| | - Meixuan Zhou
- Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
| | - Tianruo Guo
- GSBME, University of New South Wales, Graduate School of Biomedical Engineering, University of New South Wales, NSW 2052, Sydney, Australia, Sydney, New South Wales, 2052, AUSTRALIA
| | - Junling Liang
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Weilei Wu
- Shanghai Jiao Tong University, School of Biomedical Engineering Shanghai Jiao Tong University , Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Qi Gao
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai, Shanghai, 200240, CHINA
| | - Liming Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
| | - Heng Li
- Shanghai Jiao Tong University, Address: 800 Dongchuan Road, Minhang District, Shanghai Shanghai, CN 200240, Shanghai, 200240, CHINA
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
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13
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Battaglini L, Di Ponzio M, Ghiani A, Mena F, Santacesaria P, Casco C. Vision recovery with perceptual learning and non-invasive brain stimulation: Experimental set-ups and recent results, a review of the literature. Restor Neurol Neurosci 2022; 40:137-168. [PMID: 35964213 DOI: 10.3233/rnn-221261] [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: 11/15/2022]
Abstract
BACKGROUND Vision is the sense which we rely on the most to interact with the environment and its integrity is fundamental for the quality of our life. However, around the globe, more than 1 billion people are affected by debilitating vision deficits. Therefore, finding a way to treat (or mitigate) them successfully is necessary. OBJECTIVE This narrative review aims to examine options for innovative treatment of visual disorders (retinitis pigmentosa, macular degeneration, optic neuropathy, refractory disorders, hemianopia, amblyopia), especially with Perceptual Learning (PL) and Electrical Stimulation (ES). METHODS ES and PL can enhance visual abilities in clinical populations, inducing plastic changes. We describe the experimental set-ups and discuss the results of studies using ES or PL or their combination in order to suggest, based on literature, which treatment is the best option for each clinical condition. RESULTS Positive results were obtained using ES and PL to enhance visual functions. For example, repetitive transorbital Alternating Current Stimulation (rtACS) appeared as the most effective treatment for pre-chiasmatic disorders such as optic neuropathy. A combination of transcranial Direct Current Stimulation (tDCS) and visual training seems helpful for people with hemianopia, while transcranial Random Noise Stimulation (tRNS) makes visual training more efficient in people with amblyopia and mild myopia. CONCLUSIONS This narrative review highlights the effect of different ES montages and PL in the treatment of visual disorders. Furthermore, new options for treatment are suggested. It is noteworthy to mention that, in some cases, unclear results emerged and others need to be more deeply investigated.
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Affiliation(s)
- Luca Battaglini
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
| | - Michele Di Ponzio
- Department of General Psychology, University of Padova, Italy.,Istituto di Neuroscienze, Florence, Italy
| | - Andrea Ghiani
- Department of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, the Netherlands
| | - Federica Mena
- Department of General Psychology, University of Padova, Italy
| | | | - Clara Casco
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
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14
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Yu WS, Tse ACK, Guan L, Chiu JLY, Tan SZK, Khairuddin S, Agadagba SK, Lo ACY, Fung ML, Chan YS, Chan LLH, Lim LW. Antidepressant-like effects of transcorneal electrical stimulation in rat models. Brain Stimul 2022; 15:843-856. [DOI: 10.1016/j.brs.2022.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 11/02/2022] Open
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15
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Sanie-Jahromi F, Azizi A, Shariat S, Johari M. Effect of Electrical Stimulation on Ocular Cells: A Means for Improving Ocular Tissue Engineering and Treatments of Eye Diseases. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6548554. [PMID: 34840978 PMCID: PMC8612806 DOI: 10.1155/2021/6548554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/25/2021] [Accepted: 11/08/2021] [Indexed: 01/09/2023]
Abstract
Tissue engineering is biomedical engineering that uses suitable biochemical and physicochemical factors to assemble functional constructs that restore or improve damaged tissues. Recently, cell therapies as a subset of tissue engineering have been very promising in the treatment of ocular diseases. One of the most important biophysical factors to make this happen is noninvasive electrical stimulation (ES) to target ocular cells that may preserve vision in multiple retinal and optic nerve diseases. The science of cellular and biophysical interactions is very exciting in regenerative medicine now. Although the exact effect of ES on cells is unknown, multiple mechanisms are considered to underlie the effects of ES, including increased production of neurotrophic agents, improved cell migration, and inhibition of proinflammatory cytokines and cellular apoptosis. In this review, we highlighted the effects of ES on ocular cells, especially on the corneal, retinal, and optic nerve cells. Initially, we summarized the current literature on the in vitro and in vivo effects of ES on ocular cells and then we provided the clinical studies describing the effect of ES on ocular complications. For each area, we used some of the most impactful articles to show the important concepts and results that advanced the state of these interactions. We conclude with reflections on emerging new areas and perspectives for future development in this field.
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Affiliation(s)
- Fatemeh Sanie-Jahromi
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Azizi
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sahar Shariat
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammadkarim Johari
- Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
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16
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Yu WS, Kwon SH, Agadagba SK, Chan LLH, Wong KH, Lim LW. Neuroprotective Effects and Therapeutic Potential of Transcorneal Electrical Stimulation for Depression. Cells 2021; 10:cells10092492. [PMID: 34572141 PMCID: PMC8466154 DOI: 10.3390/cells10092492] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/29/2021] [Accepted: 09/17/2021] [Indexed: 12/22/2022] Open
Abstract
Transcorneal electrical stimulation (TES) has emerged as a non-invasive neuromodulation approach that exerts neuroprotection via diverse mechanisms, including neurotrophic, neuroplastic, anti-inflammatory, anti-apoptotic, anti-glutamatergic, and vasodilation mechanisms. Although current studies of TES have mainly focused on its applications in ophthalmology, several lines of evidence point towards its putative use in treating depression. Apart from stimulating visual-related structures and promoting visual restoration, TES has also been shown to activate brain regions that are involved in mood alterations and can induce antidepressant-like behaviour in animals. The beneficial effects of TES in depression were further supported by its shared mechanisms with FDA-approved antidepressant treatments, including its neuroprotective properties against apoptosis and inflammation, and its ability to enhance the neurotrophic expression. This article critically reviews the current findings on the neuroprotective effects of TES and provides evidence to support our hypothesis that TES possesses antidepressant effects.
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Affiliation(s)
- Wing-Shan Yu
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; (W.-S.Y.); (S.-H.K.); (K.-H.W.)
| | - So-Hyun Kwon
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; (W.-S.Y.); (S.-H.K.); (K.-H.W.)
| | - Stephen Kugbere Agadagba
- Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China; (S.K.A.); (L.-L.-H.C.)
| | - Leanne-Lai-Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China; (S.K.A.); (L.-L.-H.C.)
| | - Kah-Hui Wong
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; (W.-S.Y.); (S.-H.K.); (K.-H.W.)
- Department of Anatomy, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Lee-Wei Lim
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; (W.-S.Y.); (S.-H.K.); (K.-H.W.)
- Correspondence:
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17
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Blum MC, Hunold A, Solf B, Klee S. Ocular direct current stimulation affects retinal ganglion cells. Sci Rep 2021; 11:17573. [PMID: 34475417 PMCID: PMC8413326 DOI: 10.1038/s41598-021-96401-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/09/2021] [Indexed: 11/22/2022] Open
Abstract
Ocular current stimulation (oCS) with weak current intensities (a few mA) has shown positive effects on retinal nerve cells, which indicates that neurodegenerative ocular diseases could be treated with current stimulation of the eye. During oCS, a significant polarity-independent reduction in the characteristic P50 amplitude of a pattern-reversal electroretinogram was found, while no current stimulation effect was found for a full field electroretinogram (ffERG). The ffERG data indicated a trend for a polarity-dependent influence during oCS on the photopic negative response (PhNR) wave, which represents the sum activity of the retinal ganglion cells. Therefore, an ffERG with adjusted parameters for the standardized measurement of the PhNR wave was combined with simultaneous oCS to study the potential effects of direct oCS on cumulative ganglion cell activity. Compared with that measured before oCS, the PhNR amplitude in the cathodal group increased significantly during current stimulation, while in the anodal and sham groups, no effect was visible (α = 0.05, pcathodal = 0.006*). Furthermore, repeated-measures ANOVA revealed a significant difference in PhNR amplitude between the anodal and cathodal groups as well as between the cathodal and sham groups (p* ≤ 0.0167, pcathodal − anodal = 0.002*, pcathodal − sham = 0.011*).
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Affiliation(s)
- Maren-Christina Blum
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany.
| | - Alexander Hunold
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Benjamin Solf
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Sascha Klee
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany.,Department of General Health Studies, Division Biostatistics and Data Science, Karl Landsteiner University of Health Sciences, Krems, Austria
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18
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Liu J, Tong K, Lin Y, Lee VWH, So KF, Shih KC, Lai JSM, Chiu K. Effectiveness of Microcurrent Stimulation in Preserving Retinal Function of Blind Leading Retinal Degeneration and Optic Neuropathy: A Systematic Review. Neuromodulation 2021; 24:992-1002. [PMID: 33984873 DOI: 10.1111/ner.13414] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/29/2021] [Accepted: 04/19/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To systematically identify and summarize the effectiveness and the parameters of electrical stimulation (ES) for the preservation of visual function in major retinal degeneration and optic neuropathy. MATERIALS AND METHODS A systematic review of clinical studies, using ES therapy in patients with blind leading retinal degenerations, including retinitis pigmentosa (RP), age-related macular degeneration (AMD), glaucoma, retinal vein occlusion (RVO), retinal artery occlusion (RAO), and optic neuropathy was conducted. PubMed, EMBASE, Cochrane Library, and Web of Science were searched for relevant interventional studies including randomized controlled trials (RCTs) and observational studies. RESULTS A total of 10 RCTs and 15 observational studies were included. Transcorneal ES (TcES), transpalpebral ES (TpES), transdermal ES (TdES), and repetitive transorbital alternating current stimulation (rtACS) were used for the treatment of the patients. ES using 20 Hz biphasic pulses with current strength at 150%-200% of individual electrical phosphene threshold (EPT) for RP patients showed improved retinal function detected by visual acuity (VA), visual field (VF), or electrical retinal graphs (ERG). rtACS on patients with optic neuropathy showed significant preservation of VA and VF. Clinical studies on AMD, RAO, and glaucoma indicated promising protective effects of ES on the visual function, though the amount of evidence is limited. CONCLUSIONS ES treatment has promising therapeutic effects on RP and optic neuropathy. More large-scale RCT studies should be conducted to elucidate the potential of ES, especially on AMD, RAO, and glaucoma. A comparison of the effects by different ES methods in the same disease populations is still lacking. Parameters of the electric current and sensitive detection method should be optimized for the evaluation of ES treatment effects in future studies.
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Affiliation(s)
- Jinfeng Liu
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kelvin Tong
- Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Youhong Lin
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Vincent W H Lee
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kwok Fai So
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China.,Guangdong HongKong Macau Institute of CNS Regeneration: Guangdong, Guangzhou, China
| | - Kendrick Co Shih
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jimmy S M Lai
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kin Chiu
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
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19
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Shen J, Wang Y, Yao K. Protection of retinal ganglion cells in glaucoma: Current status and future. Exp Eye Res 2021; 205:108506. [PMID: 33609512 DOI: 10.1016/j.exer.2021.108506] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/29/2021] [Accepted: 02/12/2021] [Indexed: 02/08/2023]
Abstract
Glaucoma is a neuropathic disease that causes optic nerve damage, loss of retinal ganglion cells (RGCs), and visual field defects. Most glaucoma patients have no early signs or symptoms. Conventional pharmacological glaucoma medications and surgeries that focus on lowering intraocular pressure are not sufficient; RGCs continue to die, and the patient's vision continues to decline. Recent evidence has demonstrated that neuroprotective approaches could be a promising strategy for protecting against glaucoma. In the case of glaucoma, neuroprotection aims to prevent or slow down disease progression by mitigating RGCs death and optic nerve degeneration. Notably, new pharmacologic medications such as antiglaucomatous agents, antibiotics, dietary supplementation, novel neuroprotective molecules, neurotrophic factors, translational methods such as gene therapy and cell therapy, and electrical stimulation-based physiotherapy are emerging to attenuate the death of RGCs, or to make RGCs resilient to attacks. Understanding the roles of these interventions in RGC protection may offer benefits over traditional pharmacological medications and surgeries. In this review, we summarize the recent neuroprotective strategy for glaucoma, both in clinical trials and in laboratory research.
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Affiliation(s)
- Junhui Shen
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Yuanqi Wang
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Ke Yao
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
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20
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Blum MC, Solf B, Hunold A, Klee S. Effects of Ocular Direct Current Stimulation on Full Field Electroretinogram. Front Neurosci 2021; 15:606557. [PMID: 33679299 PMCID: PMC7928396 DOI: 10.3389/fnins.2021.606557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Studies on weak current stimulation (1-2 mA) examine effects on neuronal cells for the treatment of neurological diseases, like depression. Ocular current stimulation showed positive effects on retinal nerve cells which indicate that neurodegenerative ocular diseases, e.g., glaucoma, can be treated with current stimulation of the eye. However, up to now it remains unclear which exact retinal cells can be influenced. During an ocular direct current stimulation, a significant reduction of the characteristic P50 amplitude of a pattern-reversal electroretinogram (PERG) was found for an anodal and a cathodal stimulation. This current stimulation effect could originate from the modulation of pre-ganglion cell activity or by changes in local ON and OFF responses of ganglion cells. For clarification, we investigate acute direct current stimulation effects on a full field electroretinogram (ERG), which represents the activity of pre-ganglion cells (specifically cones and bipolar cells). The ERG from 15 subjects was evaluated before (ERG 1) and during (ERG 2) an ocular direct current stimulation with 800 μA over 5 min. The current was applied through a ring rubber electrode placed around the eye and a 25 cm2 rubber electrode placed at the ipsilateral temple. For ERG measurements, sintered Ag/AgCl skin-electrodes were positioned on the lower eyelid (active), the earlobe (reference), and the forehead (ground). The volunteers were stimulated in three independent sessions, each with a different current application (randomized order): cathodal polarity, anodal polarity (referred to the electrode around the eye), or sham stimulation. The changes between the two ERG measurements of the characteristic full field ERG amplitudes, a-wave, b-wave, and b'-wave (b-wave measured from zero line) were tested with the Wilcoxon signed-rank test (α = 0.05). Comparing before to during the current stimulation for all applications, the ERG waves showed no effects on amplitudes or latencies. Furthermore, no significant difference between the cathodal, anodal, and sham stimulation could be found by a Friedman test. These results indicate an unlikely contribution of pre-ganglion cells to the previously reported stimulation effect on PERG signals.
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Affiliation(s)
- Maren-Christina Blum
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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21
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Agadagba SK, Li X, Chan LLH. Excitation of the Pre-frontal and Primary Visual Cortex in Response to Transcorneal Electrical Stimulation in Retinal Degeneration Mice. Front Neurosci 2020; 14:572299. [PMID: 33162879 PMCID: PMC7584448 DOI: 10.3389/fnins.2020.572299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/08/2020] [Indexed: 11/13/2022] Open
Abstract
Retinal degeneration (rd) is one of the leading causes of blindness in the modern world today. Various strategies including electrical stimulation are being researched for the restoration of partial or complete vision. Previous studies have demonstrated that the effectiveness of electrical stimulation in somatosensory, frontal and visual cortices is dependent on stimulation parameters including stimulation frequency and brain states. The aim of the study is to investigate the effect of applying a prolonged electrical stimulation on the eye of rd mice with various stimulation frequencies, in awake and anesthetized brain states. We recorded spontaneous electrocorticogram (ECoG) neural activity in prefrontal cortex and primary visual cortex in a mouse model of retinitis pigmentosa (RP) after prolonged (5-day) transcorneal electrical stimulation (pTES) at various frequencies (2, 10, and 20 Hz). We evaluated the absolute power and coherence of spontaneous ECoG neural activities in contralateral primary visual cortex (contra Vcx) and contralateral pre-frontal cortex (contra PFx). Under the awake state, the absolute power of theta, alpha and beta oscillations in contra Vcx, at 10 Hz stimulation, was higher than in the sham group. Under the anesthetized state, the absolute power of medium-, high-, and ultra-high gamma oscillations in the contra PFx, at 2 Hz stimulation, was higher than in the sham group. We also observed that the ultra-high gamma band coherence in contra Vcx-contra PFx was higher than in the sham group, with both 10 and 20 Hz stimulation frequencies. Our results showed that pTES modulates rd brain oscillations in a frequency and brain state-dependent manner. These findings suggest that non-invasive electrical stimulation of retina changes patterns of neural oscillations in the brain circuitry. This also provides a starting point for investigating the sustained effect of electrical stimulation of the retina to brain activities.
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Affiliation(s)
- Stephen K Agadagba
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong
| | - Xin Li
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong
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22
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Perin C, Viganò B, Piscitelli D, Matteo BM, Meroni R, Cerri CG. Non-invasive current stimulation in vision recovery: a review of the literature. Restor Neurol Neurosci 2020; 38:239-250. [PMID: 31884495 PMCID: PMC7504999 DOI: 10.3233/rnn-190948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Background: Around 253 million people worldwide suffer from irreversible visual damage. Numerous studies have been carried out in order to unveil the effects of electrical stimulation (ES) as a useful tool for rehabilitation for different visual conditions and pathologies. Objective: This systematic review aimed to 1) examine the current evidence of ES efficacy for the treatment of visual pathologies and 2) define the corresponding degree of the recommendation of different ES techniques. Methods: A systematic review was conducted in MEDLINE and Cochrane Library database to collect documents published between 2000 and 2018. For each study, Level of Evidence of Effectiveness of ES as well as the Class of Quality for the treatment of different visual pathologies were determined. Results: Thirty-eight articles were included. Studies were grouped according to the pathology treated and the type of stimulation administered. The first group included studies treating pre-chiasmatic pathologies (age-related macular degeneration, macular dystrophy, retinal artery occlusion, retinitis pigmentosa, glaucoma, optic nerve damage, and optic neuropathy) using pre-chiasmatic stimulation; the second group included studies treating both pre-chiasmatic pathologies (amblyopia, myopia) and post-chiasmatic pathologies or brain conditions (hemianopsia, brain trauma) by means of post-chiasmatic stimulation. In the first group, repetitive transorbital alternating current stimulation (rtACS) reached level A recommendation, and transcorneal electrical stimulation (tcES) reached level B. In the second group, both high-frequency random noise stimulation (hf-RNS) and transcranial direct current stimulation (tDCS) reached level C recommendation. Conclusions: Study’s findings suggest conclusive evidence for rtACS treatment. For other protocols results are promising but not conclusive since the examined studies assessed different stimulation parameters and endpoints. A comparison of the effects of different combinations of these variables still lacks in the literature. Further studies are needed to optimize existing protocols and determine if different protocols are needed for different diseases.
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Affiliation(s)
- Cecilia Perin
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy
| | | | - Daniele Piscitelli
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
| | - Barbara Maria Matteo
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy
| | - Roberto Meroni
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy.,Current Affilation: Department of Physiotherapy, LUNEX International University of Health, Exercise and Sports. Differdange, Luxembourg
| | - Cesare Giuseppe Cerri
- Dipartimento di Medicina e Chirurgia (School of Medicine and Surgery), University of Milan-Bicocca, Milan, Italy.,Milan Center for Neuroscience (NeuroMI), University of Milan-Bicocca, Milan, Italy
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23
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Blum MC, Hunold A, Solf B, Klee S. The Effects of an Ocular Direct Electrical Stimulation on Pattern-Reversal Electroretinogram. Front Neurosci 2020; 14:588. [PMID: 32587502 PMCID: PMC7298143 DOI: 10.3389/fnins.2020.00588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/13/2020] [Indexed: 02/02/2023] Open
Abstract
Studies on transcranial current stimulation have shown that a direct current stimulation of the occipital cortex can influence the amplitude size of a visual evoked potential (VEP). The current direction (cathodal or anodal) determines whether the VEP amplitudes increase or decrease. The aim of this study was to design a new experimental setup that will enable a simultaneous ocular direct current stimulation and electroretinogram (ERG) recording which will broaden our understanding of current stimulation effects on the visual system. Furthermore, we examined whether a direct current stimulation on the eye has a similar effect on an ERG as on a VEP. The pattern-reversal ERG was measured with sintered Ag/AgCl skin-electrodes, positioned on the lower eyelid (active), the earlobe (reference), and the forehead (ground). Direct current was applied through a ring rubber electrode placed around the eye and a 5 cm × 5 cm rubber electrode placed at the ipsilateral temple with a current strength of 500 μA and a duration time of 5 min. Fifty-seven healthy volunteers were divided into three groups depending on the current direction (cathodal, anodal, and sham stimulation, n = 19 each). One ERG measurement (ERG 1) was performed before and another (ERG 2) during the direct current stimulation. The difference between ERG 1 and ERG 2 measurements for the characteristic P50, N95 and N95' (N95 minimum measured from zero line) amplitudes were evaluated by both confidence interval analysis and t-test for related samples (α = 0.05, after Bonferroni correction p ∗ = 0.0055). The P50 amplitude was significantly decreased for ERG 2 measurement in the cathodal and anodal stimulation group (cathodal p = 0.001, anodal p = 0.000). No significant changes could be found in the N95 and N95' amplitudes as well as in the sham-stimulation group. Additionally, the latencies did not undergo any significant changes. In conclusion, the newly designed experimental setup enables simultaneous current stimulation and ERG recording. The current influenced P50 amplitude although not the N95 and N95' amplitudes. Furthermore, the amplitude size decreased for both current directions and did not lead to contrary effects as expected.
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Affiliation(s)
- Maren-Christina Blum
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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24
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Kurimoto T, Ueda K, Mori S, Kamada S, Sakamoto M, Yamada-Nakanishi Y, Matsumiya W, Nakamura M. A Single-Arm, Prospective, Exploratory Study to Preliminarily Test Effectiveness and Safety of Skin Electrical Stimulation for Leber Hereditary Optic Neuropathy. J Clin Med 2020; 9:jcm9051359. [PMID: 32384676 PMCID: PMC7290509 DOI: 10.3390/jcm9051359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 11/16/2022] Open
Abstract
Leber hereditary optic neuropathy (LHON) is an intractable disease associated with mitochondrial DNA (mtDNA) mutations. In this preliminary, single-arm, prospective, open-label exploratory trial, we investigated the effectiveness and safety of skin electrical stimulation (SES) for cases of LHON harboring the mtDNA 11,778 mutation. Of the 11 enrolled patients, 10 completed six sessions of SES once every two weeks over a 10-week period. The primary outcome measure was the change in logarithm of the minimum angle of resolution (logMAR)-converted best-corrected visual acuity (BCVA) at one week after the last session of SES. The main secondary outcome measures were the logMAR BCVA at four and eight weeks and Humphrey visual field test sensitivities at one, four, and eight weeks. At all follow-up points, the logMAR BCVA had improved significantly from baseline, [1.80 (1.70–1.80) at baseline, 1.75 (1.52–1.80) at one week, 1.75 (1.50–1.80) at four weeks, and 1.75 (1.52–1.80) at eight weeks; p < 0.05]. At eight weeks of follow-up, five patients showed >2-fold increase in the summed sensitivity at 52 measurement points from baseline. No adverse effects were observed. In conclusion, SES could be a viable treatment option for patients with LHON in the chronic phase harboring the mtDNA 11,778 mutation.
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Affiliation(s)
- Takuji Kurimoto
- Correspondence: ; Tel.: +81-78-382-6048; Fax: 81-78-382-6059
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25
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Adair D, Truong D, Esmaeilpour Z, Gebodh N, Borges H, Ho L, Bremner JD, Badran BW, Napadow V, Clark VP, Bikson M. Electrical stimulation of cranial nerves in cognition and disease. Brain Stimul 2020; 13:717-750. [PMID: 32289703 PMCID: PMC7196013 DOI: 10.1016/j.brs.2020.02.019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.
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Affiliation(s)
- Devin Adair
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Dennis Truong
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
| | - Nigel Gebodh
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Helen Borges
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Libby Ho
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - J Douglas Bremner
- Department of Psychiatry & Behavioral Sciences and Radiology, Emory University School of Medicine, Atlanta, GA, USA; Atlanta VA Medical Center, Decatur, GA, USA
| | - Bashar W Badran
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Vitaly Napadow
- Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Harvard medical school, Boston, MA, USA
| | - Vincent P Clark
- Psychology Clinical Neuroscience Center, Dept. Psychology, MSC03-2220, University of New Mexico, Albuquerque, NM, 87131, USA; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA; The Mind Research Network of the Lovelace Biomedical Research Institute, 1101 Yale Blvd. NE, Albuquerque, NM, 87106, USA
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
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26
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Sabel BA, Thut G, Haueisen J, Henrich-Noack P, Herrmann CS, Hunold A, Kammer T, Matteo B, Sergeeva EG, Waleszczyk W, Antal A. Vision modulation, plasticity and restoration using non-invasive brain stimulation – An IFCN-sponsored review. Clin Neurophysiol 2020; 131:887-911. [DOI: 10.1016/j.clinph.2020.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 12/18/2019] [Accepted: 01/02/2020] [Indexed: 12/11/2022]
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27
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Freitag S, Hunold A, Klemm M, Klee S, Link D, Nagel E, Haueisen J. Pulsed Electrical Stimulation of the Human Eye Enhances Retinal Vessel Reaction to Flickering Light. Front Hum Neurosci 2019; 13:371. [PMID: 31695600 PMCID: PMC6817672 DOI: 10.3389/fnhum.2019.00371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 09/30/2019] [Indexed: 12/11/2022] Open
Abstract
Recent studies indicate therapeutic benefits of electrical stimulation in cases of specific ophthalmic diseases that are associated with dysfunctional ocular microcirculation. This suggests effects of electrical stimulation on vascular functions. In the present study, we investigated the effects of electrical stimulation on retinal vessel reactions using dynamic vessel analysis (DVA). Eighty healthy subjects were randomly assigned to one of three groups receiving electrical stimulation with different current intensities: 400 μA (n = 26); 800 μA (n = 27); 1200 μA (n = 27). The electrode montage for electrical stimulation consisted of a ring-shaped active electrode surrounding one eye and a square return electrode at the occiput. Rectangular, monophasic, positive current pulses were applied at 10 Hz for a duration of 60 s per stimulation period. DVA was used to observe the stimulation-induced reactions of retinal vessel diameters in response to different provocations. In three DVA measurements, three stimulus conditions were investigated: flicker light stimulation (FLS); electrical stimulation (ES); simultaneous electrical and flicker light stimulation (ES+FLS). Retinal vasodilation caused by these stimuli was compared using paired t-test. The subjects receiving electrical stimulation with 800 μA showed significantly increased retinal vasodilation for ES+FLS compared to FLS (p < 0.05). No significant differences in retinal vessel reactions were found between ES+FLS and FLS in the 400 and 1200 μA groups. No retinal vasodilation was observed for ES for all investigated current intensities. The results indicate that positive pulsed electrical stimulation of an adequate intensity enhances the flicker light-induced retinal vasodilation.
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Affiliation(s)
- Stefanie Freitag
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Alexander Hunold
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Matthias Klemm
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Sascha Klee
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Dietmar Link
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Edgar Nagel
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany.,Ophthalmic Private Practice, Rudolstadt, Germany
| | - Jens Haueisen
- Institute for Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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28
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Bikson M, Esmaeilpour Z, Adair D, Kronberg G, Tyler WJ, Antal A, Datta A, Sabel BA, Nitsche MA, Loo C, Edwards D, Ekhtiari H, Knotkova H, Woods AJ, Hampstead BM, Badran BW, Peterchev AV. Transcranial electrical stimulation nomenclature. Brain Stimul 2019; 12:1349-1366. [PMID: 31358456 DOI: 10.1016/j.brs.2019.07.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/25/2019] [Accepted: 07/14/2019] [Indexed: 01/03/2023] Open
Abstract
Transcranial electrical stimulation (tES) aims to alter brain function non-invasively by applying current to electrodes on the scalp. Decades of research and technological advancement are associated with a growing diversity of tES methods and the associated nomenclature for describing these methods. Whether intended to produce a specific response so the brain can be studied or lead to a more enduring change in behavior (e.g. for treatment), the motivations for using tES have themselves influenced the evolution of nomenclature, leading to some scientific, clinical, and public confusion. This ambiguity arises from (i) the infinite parameter space available in designing tES methods of application and (ii) varied naming conventions based upon the intended effects and/or methods of application. Here, we compile a cohesive nomenclature for contemporary tES technologies that respects existing and historical norms, while incorporating insight and classifications based on state-of-the-art findings. We consolidate and clarify existing terminology conventions, but do not aim to create new nomenclature. The presented nomenclature aims to balance adopting broad definitions that encourage flexibility and innovation in research approaches, against classification specificity that minimizes ambiguity about protocols but can hinder progress. Constructive research around tES classification, such as transcranial direct current stimulation (tDCS), should allow some variations in protocol but also distinguish from approaches that bear so little resemblance that their safety and efficacy should not be compared directly. The proposed framework includes terms in contemporary use across peer-reviewed publications, including relatively new nomenclature introduced in the past decade, such as transcranial alternating current stimulation (tACS) and transcranial pulsed current stimulation (tPCS), as well as terms with long historical use such as electroconvulsive therapy (ECT). We also define commonly used terms-of-the-trade including electrode, lead, anode, and cathode, whose prior use, in varied contexts, can also be a source of confusion. This comprehensive clarification of nomenclature and associated preliminary proposals for standardized terminology can support the development of consensus on efficacy, safety, and regulatory standards.
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Affiliation(s)
- Marom Bikson
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Devin Adair
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - Greg Kronberg
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - William J Tyler
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center Goettingen, Goettingen, Germany; Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | | | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Michael A Nitsche
- Leibniz Research Centre for Working Environment ant Human Factors, Dept. Psychology and Neurosciences, Dortmund, Germany; University Medical Hospital Bergmannsheil, Dept. Neurology, Bochum, Germany
| | - Colleen Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Dylan Edwards
- Moss Rehabilitation Research Institute, Philadelphia, PA, USA; Edith Cowan University, Joondalup, Australia
| | | | - Helena Knotkova
- MJHS Institute for Innovation in Palliative Care, New York, NY, USA; Department of Family and Social Medicine, Albert Einstein College of Medicine, The Bronx, NY, USA
| | - Adam J Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Benjamin M Hampstead
- Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Neuropsychology Section, Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Bashar W Badran
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - Angel V Peterchev
- Department of Psychiatry & Behavioral Sciences, Department of Biomedical Engineering, Department of Electrical & Computer Engineering, Department of Neurosurgery, Duke University, Durham, NC, USA
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29
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Kurimoto T, Ueda K, Mori S, Sakamoto M, Yamada-Nakanishi Y, Matsumiya W, Nakamura M. A study protocol for evaluating the efficacy and safety of skin electrical stimulation for Leber hereditary optic neuropathy: a single-arm, open-label, non-randomized prospective exploratory study. Clin Ophthalmol 2019; 13:897-904. [PMID: 31213761 PMCID: PMC6549395 DOI: 10.2147/opth.s204669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 04/12/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Leber hereditary optic neuropathy (LHON) is a maternally inherited disease caused by three missense mutations of mitochondrial (mt) DNA, ie, m 3460 G>A, m 11778 G>A, or m 14484 T>C in the greater portion of LHON. m 11778 G>A mutation is especially observed in >90% of the cases in Japanese families. Although spontaneous remission of visual function infrequently occurs, effective treatment for LHON remains unestablished. Transcorneal electrical stimulation has been shown to be efficacious in individuals with optic neuropathy. However, due to potential risk of corneal damage, repeated treatments are not permissible. In this exploratory study, we will be conducting skin electrical stimulation (SES) as an intervention for patients with LHON having 11778 missense mutation and investigate effectiveness and safety of SES. Methods: This is a single-arm, prospective, open-label exploratory trial focused on patients with LHON having 11778 missense mutation. Eleven patients will be enrolled and receive six consecutive SES once every 2 weeks up to 10 weeks. The safety of the SES will be monitored with specular microscopy, slit-lamp biomicroscopy, fundus examinations, and the observation of facial skin. The primary outcome measure will be the averaged l ogarithm of minimum angle resolution (logMAR) converted visual acuity 1 week after the last SES. Secondary outcome measures include changes, in logMAR at 4 and 8 weeks after the last SES, such as visual field indices measured using Humphrey visual field and microperimetry-3, the thickness of peripapillary retinal fiber and macular ganglion cell complex, multifocal visual evoked potentials, critical flicker frequency, and color vision. Discussion: The results of this proposed proof-of-concept feasibility trial will help plan and execute a larger definitive trial to test SES as an effective strategy for LHON and related optic neuropathies and help establish a beneficial treatment for LHON.
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Affiliation(s)
- Takuji Kurimoto
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kaori Ueda
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sotaro Mori
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Mari Sakamoto
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuko Yamada-Nakanishi
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Wataru Matsumiya
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Makoto Nakamura
- Division of Ophthalmology, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
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Pardue MT, Allen RS. Neuroprotective strategies for retinal disease. Prog Retin Eye Res 2018; 65:50-76. [PMID: 29481975 PMCID: PMC6081194 DOI: 10.1016/j.preteyeres.2018.02.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/14/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Diseases that affect the eye, including photoreceptor degeneration, diabetic retinopathy, and glaucoma, affect 11.8 million people in the US, resulting in vision loss and blindness. Loss of sight affects patient quality of life and puts an economic burden both on individuals and the greater healthcare system. Despite the urgent need for treatments, few effective options currently exist in the clinic. Here, we review research on promising neuroprotective strategies that promote neuronal survival with the potential to protect against vision loss and retinal cell death. Due to the large number of neuroprotective strategies, we restricted our review to approaches that we had direct experience with in the laboratory. We focus on drugs that target survival pathways, including bile acids like UDCA and TUDCA, steroid hormones like progesterone, therapies that target retinal dopamine, and neurotrophic factors. In addition, we review rehabilitative methods that increase endogenous repair mechanisms, including exercise and electrical stimulation therapies. For each approach, we provide background on the neuroprotective strategy, including history of use in other diseases; describe potential mechanisms of action; review the body of research performed in the retina thus far, both in animals and in humans; and discuss considerations when translating each treatment to the clinic and to the retina, including which therapies show the most promise for each retinal disease. Despite the high incidence of retinal diseases and the complexity of mechanisms involved, several promising neuroprotective treatments provide hope to prevent blindness. We discuss attractive candidates here with the goal of furthering retinal research in critical areas to rapidly translate neuroprotective strategies into the clinic.
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Affiliation(s)
- Machelle T Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, GA, 30332, USA.
| | - Rachael S Allen
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA
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Electrical Stimulation as a Means for Improving Vision. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 186:2783-2797. [PMID: 27643530 DOI: 10.1016/j.ajpath.2016.07.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 12/31/2022]
Abstract
Evolving research has provided evidence that noninvasive electrical stimulation (ES) of the eye may be a promising therapy for either preserving or restoring vision in several retinal and optic nerve diseases. In this review, we focus on minimally invasive strategies for the delivery of ES and accordingly summarize the current literature on transcorneal, transorbital, and transpalpebral ES in both animal experiments and clinical studies. Various mechanisms are believed to underlie the effects of ES, including increased production of neurotrophic agents, improved chorioretinal blood circulation, and inhibition of proinflammatory cytokines. Different animal models have demonstrated favorable effects of ES on both the retina and the optic nerve. Promising effects of ES have also been demonstrated in clinical studies; however, all current studies have a lack of randomization and/or a control group (sham). There is thus a pressing need for a deeper understanding of the underlying mechanisms that govern clinical success and optimization of stimulation parameters in animal studies. In addition, such research should be followed by large, prospective, clinical studies to explore the full potential of ES. Through this review, we aim to provide insight to guide future research on ES as a potential therapy for improving vision.
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The Efficacy of Transcorneal Electrical Stimulation for the Treatment of Primary Open-angle Glaucoma: A Pilot Study. Keio J Med 2017; 67:45-53. [DOI: 10.2302/kjm.2017-0015-oa] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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RETRACTED ARTICLE: Transkorneale Elektrostimulation bei Patienten mit primärem Offenwinkelglaukom. Ophthalmologe 2015; 112:694. [DOI: 10.1007/s00347-014-3071-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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