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Abstract
PURPOSE OF REVIEW Electrophysiological measures of vision function have for decades generated interest among glaucoma researchers and clinicians alike because of their potential to help elucidate pathophysiological processes and sequence of glaucomatous damage, as well as to offer a potential complementary metric of function that might be more sensitive than standard automated perimetry. The purpose of this article is to review the recent literature to provide an update on the role of the electroretinogram (ERG) in glaucoma diagnosis. RECENT FINDINGS The pattern reversal ERG (PERG) and the photopic negative response (PhNR) of the cone-driven full-field, focal or multifocal ERG provide objective measures of retinal ganglion cell function and are all sensitive to glaucomatous damage. Recent studies demonstrate that a reduced PERG amplitude is predictive of subsequent visual field conversion (from normal to glaucomatous) and an increased rate of progressive retinal nerve fiber layer thinning in suspect eyes, indicating a potential role for PERG in risk stratification. Converging evidence indicates that some portion of PERG and PhNR abnormality represents a reversible aspect of dysfunction in glaucoma. SUMMARY PERG and PhNR responses obtained from the central macula are capable of detecting early-stage, reversible glaucomatous dysfunction.
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Wu Z, Hadoux X, Fan Gaskin JC, Sarossy MG, Crowston JG. Measuring the Photopic Negative Response: Viability of Skin Electrodes and Variability Across Disease Severities in Glaucoma. Transl Vis Sci Technol 2016; 5:13. [PMID: 26998406 PMCID: PMC4795588 DOI: 10.1167/tvst.5.2.13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/12/2016] [Indexed: 12/05/2022] Open
Abstract
PURPOSE The purpose of this study was to determine the feasibility of measuring the photopic negative response (PhNR) of the full-field electroretinogram (ERG) using skin electrodes compared to conjunctival electrodes and its test-retest variability over a range of disease severities in open-angle glaucoma. METHODS Recordings were performed twice (100 sweeps each) within the same session in 43 eyes of 23 participants with glaucoma to determine its intrinsic variability. The ratio between the PhNR and B-wave amplitude (PhNR/B ratio) was determined for each trace and computed across 5 to 100 sweeps of each recording. Spectral-domain optical coherence tomography was used to measure the average peripapillary retinal nerve fiber layer (RNFL) thickness. RESULTS The PhNR/B ratio and its magnitude of variability were not significantly different between skin and conjunctival electrodes (P ≤ 0.197), and the degree of variability decreased substantially with increasing number of sweeps. For skin electrodes, the intraclass correlation coefficient was 0.89 and 0.91 for right and left eyes, respectively. The variability of the PhNR/B ratio decreased with lower RNFL thickness values and larger B-wave amplitudes (P ≤ 0.002). CONCLUSIONS Skin electrodes are a viable alternative to conjunctival electrodes when measuring the PhNR in open angle glaucoma, and increasing the number of sweeps substantially reduced its intrinsic variability; the extent of variability was also lower with worsening disease severity. TRANSLATIONAL RELEVANCE The feasibility of performing ERG recordings widely across a range of disease severities in glaucoma can be achieved through using skin electrodes and increasing the number of sweeps performed to improve measurement repeatability.
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Affiliation(s)
- Zhichao Wu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Xavier Hadoux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Jennifer C. Fan Gaskin
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Marc G. Sarossy
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
| | - Jonathan G. Crowston
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
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Noonan JE, Ward GM, Sarossy M, Man REK, Nguyen TT, Jenkins AJ, Dusting GJ, Lamoureux EL. Retinal neuronal and vascular function in type 1 diabetes adults during glycaemic clamps. Clin Exp Pharmacol Physiol 2016; 43:382-4. [PMID: 26748565 DOI: 10.1111/1440-1681.12540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Jonathan E Noonan
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Glenn M Ward
- Departments of Endocrinology and Diabetes, and Clinical Biochemistry, St. Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Department of Pathology, University of Melbourne, Melbourne, Victoria, Australia
| | - Marc Sarossy
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia.,RMIT University, Melbourne, Victoria, Australia
| | - Ryan E K Man
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Singapore Eye Research Institute and Department of Ophthalmology, National University of Singapore, Singapore City, Singapore
| | - Thanh T Nguyen
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Alicia J Jenkins
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia.,Queen's University, Belfast, UK
| | - Gregory J Dusting
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Ecosse L Lamoureux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Singapore Eye Research Institute and Department of Ophthalmology, National University of Singapore, Singapore City, Singapore.,Duke-NUS Graduate Medical School, Singapore City, Singapore
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Nguyen BN, Lek JJ, Vingrys AJ, McKendrick AM. Clinical impact of migraine for the management of glaucoma patients. Prog Retin Eye Res 2015; 51:107-24. [PMID: 26232725 DOI: 10.1016/j.preteyeres.2015.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 12/19/2022]
Abstract
Migraine is a common and debilitating primary headache disorder that affects 10-15% of the general population, particularly people of working age. Migraine is relevant to providers of clinical eye-care because migraine attacks are associated with a range of visual sensory symptoms, and because of growing evidence that the results of standard tests of visual function necessary for the diagnosis and monitoring of glaucoma (visual fields, electrophysiology, ocular imaging) can be abnormal due to migraine. These abnormalities are measureable in-between migraine events (the interictal period), despite patients being asymptomatic and otherwise healthy. This picture is further complicated by epidemiological data that suggests an increased prevalence of migraine in patients with glaucoma, particularly in patients with normal tension glaucoma. We discuss how migraine, as a co-morbidity, can confound the results and interpretation of clinical tests that form part of contemporary glaucoma evaluation, and provide practical evidence-based recommendations for the clinical testing and management of patients with migraine who attend eye-care settings.
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Affiliation(s)
- Bao N Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia.
| | - Jia Jia Lek
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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Can Variability of Pattern ERG Signal Help to Detect Retinal Ganglion Cells Dysfunction in Glaucomatous Eyes? BIOMED RESEARCH INTERNATIONAL 2015; 2015:571314. [PMID: 26167489 PMCID: PMC4475748 DOI: 10.1155/2015/571314] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/30/2014] [Accepted: 01/01/2015] [Indexed: 11/29/2022]
Abstract
Objective. To evaluate variability of steady-state pattern electroretinogram (SS-PERG) signal in normal, suspected, and glaucomatous eyes. Methods. Twenty-one subjects with suspected glaucoma due to disc abnormalities (GS), 37 patients with early glaucoma (EG), and 24 normal control (NC) were tested with spectral-domain optical coherence tomography (SD-OCT), standard automated perimetry (SAP), and SS-PERG. Mean deviation (MD), pattern standard deviation (PSD), retinal nerve fiber layer (RNFL), and ganglionar complex cells (GCC) were evaluated. The SS-PERG was recorded five consecutive times and the amplitude and phase of second harmonic were measured. PERG amplitude and coefficient of variation of phase (CVphase) were recorded, and correlation with structural and functional parameters of disease, by means of one-way ANOVA and Pearson's correlation, was analysed. Results. PERG amplitude was reduced, as expression of retinal ganglion cells (RGCs) dysfunction, in EG patients and GS subjects compared to NC patients (P < 0.0001). CVphase was significantly increased in EG patients and GS subjects, compared to healthy (P < 0.0001), and it was also correlated with PSD (P = 0.0009), GCC (P = 0.028), and RNFL (P = 0.0078) only in EG patients. Conclusions. Increased intrasession variability of phase in suspected glaucomatous eyes may be a sign of RGCs dysfunction.
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Parisi V, Centofanti M, Ziccardi L, Tanga L, Michelessi M, Roberti G, Manni G. Treatment with citicoline eye drops enhances retinal function and neural conduction along the visual pathways in open angle glaucoma. Graefes Arch Clin Exp Ophthalmol 2015; 253:1327-40. [PMID: 26004075 DOI: 10.1007/s00417-015-3044-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/07/2015] [Accepted: 04/29/2015] [Indexed: 10/23/2022] Open
Abstract
PURPOSE To evaluate the retinal function and the neural conduction along the visual pathways after treatment with citicoline eye drops in patients with open angle glaucoma (OAG). METHODS Fifty-six OAG patients (mean age 52.4 ± 4.72 years, IOP <18 mmHg with beta-blocker monotherapy only) were enrolled. Of these, 47 eyes completed the study: 24 OAG eyes were treated with topical citicoline (OMK1®, Omikron Italia, 3 drops/day) (GC eyes) over a 4-month period (month 4) followed by a 2-month period of citicoline wash-out (month 6), and another 23 OAG eyes were only treated with beta-blocker monotherapy (GP eyes). In GC and GP eyes, pattern electroretinogram (PERG) and visual evoked potentials (VEP) were assessed at baseline and at months 4 and 6 in both groups. RESULTS At baseline, similar (ANOVA, p > 0.01) PERG and VEP values in GC and GP eyes were observed. After treatment with topical citicoline, a significant (p < 0.01) increase of PERG P50-N95 and VEP N75-P100 amplitudes, and a significant (p < 0.01) shortening of VEP P100 implicit times were found. In GC eyes, the shortening of VEP P100 implicit times was correlated significantly (p < 0.01) with the increase of PERG P50-N95 amplitudes. After a 2-month period of topical Citicoline wash-out, PERG and VEP values were similar (p > 0.01) to baseline ones. GP eyes showed not significant changes of PERG and VEP values during the entire follow-up. CONCLUSIONS Topical treatment with citicoline in OAG eyes induces an enhancement of the retinal bioelectrical responses (increase of PERG amplitude) with a consequent improvement of the bioelectrical activity of the visual cortex (shortening and increase of VEP implicit time and amplitude, respectively).
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Affiliation(s)
- Vincenzo Parisi
- "G.B. Bietti" Foundation for Study and Research in Ophthalmology - IRCCS, Via Livenza 3, 000198, Rome, Italy
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Differential effects of optic media opacities on simultaneous multifocal pattern electroretinograms and visual evoked potentials. Clin Neurophysiol 2014; 125:2418-26. [DOI: 10.1016/j.clinph.2014.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 03/05/2014] [Accepted: 03/18/2014] [Indexed: 11/23/2022]
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Bach M, Ramharter-Sereinig A. Pattern electroretinogram to detect glaucoma: comparing the PERGLA and the PERG Ratio protocols. Doc Ophthalmol 2013; 127:227-38. [DOI: 10.1007/s10633-013-9412-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 09/30/2013] [Indexed: 10/26/2022]
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Banitt MR, Ventura LM, Feuer WJ, Savatovsky E, Luna G, Shif O, Bosse B, Porciatti V. Progressive loss of retinal ganglion cell function precedes structural loss by several years in glaucoma suspects. Invest Ophthalmol Vis Sci 2013; 54:2346-52. [PMID: 23412088 DOI: 10.1167/iovs.12-11026] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PURPOSE We determined the time lag between loss of retinal ganglion cell function and retinal nerve fiber layer (RNFL) thickness. METHODS Glaucoma suspects were followed for at least four years. Patients underwent pattern electroretinography (PERG), optical coherence tomography (OCT) of the RNFL, and standard automated perimetry testing at 6-month intervals. Comparisons were made between changes in all testing modalities. To compare PERG and OCT measurements on a normalized scale, we calculated the dynamic range of PERG amplitude and RNFL thickness. The time lag between function and structure was defined as the difference in time-to-criterion loss between PERG amplitude and RNFL thickness. RESULTS For PERG (P < 0.001) and RNFL (P = 0.030), there was a statistically significant difference between the slopes corresponding to the lowest baseline PERG amplitude stratum (≤50%) and the reference stratum (>90%). Post hoc comparisons demonstrated highly significant differences between RNFL thicknesses of eyes in the stratum with most severely affected PERG (≤50%) and the two strata with least affected PERG (>70%). Estimates suggested that the PERG amplitude takes 1.9 to 2.5 years to lose 10% of its initial amplitude, whereas the RNFL thickness takes 9.9 to 10.4 years to lose 10% of its initial thickness. Thus, the time lag between PERG amplitude and RNFL thickness to lose 10% of their initial values is on the order of 8 years. CONCLUSIONS In patients who are glaucoma suspects, PERG signal anticipates an equivalent loss of OCT signal by several years.
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Affiliation(s)
- Michael R Banitt
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
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Bach M, Poloschek CM. Electrophysiology and glaucoma: current status and future challenges. Cell Tissue Res 2013; 353:287-96. [PMID: 23525754 DOI: 10.1007/s00441-013-1598-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 02/21/2013] [Indexed: 11/25/2022]
Abstract
Visual electrophysiology allows non-invasive monitoring of the function of most processing stages along the visual pathway. Here, we consider which of the available methods provides the most information concerning glaucomatous optic nerve disease. The multifocal electroretinogram (ERG), although often employed, is less affected in glaucoma than two direct measurements of retinal ganglion cell function, namely the pattern ERG (PERG) and the photopic negative response (PhNR) of the ERG. For the PERG, longitudinal studies have been reported, suggesting that this method can be used for the early detection of glaucoma; for the PhNR, no longitudinal study is available as yet. The multifocal PERG can spatially resolve ganglion cell function but its glaucomatous reduction is typically panretinal, even with only local field changes and so, its topographic resolution is of no advantage in glaucoma. The multifocal visual evoked potential promises objective perimetry and shows sensitivity and specificity comparable with standard automated perimetry but has not been established as a routine tool to date.
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Affiliation(s)
- Michael Bach
- Section Visual Function, Department of Ophthalmology, University of Freiburg, Freiburg, Germany.
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Abstract
PURPOSE To prospectively monitor progressive changes of retinal ganglion cell function in early glaucoma using the pattern electroretinogram (PERG). METHODS Fifty-nine patients enrolled as glaucoma suspects were observed untreated over an average of 5.7±1.4 years, during which they were tested with PERG (PERGLA paradigm) and standard automated perimetry (SAP) 2 times per year. PERG amplitude and phase were normalized for physiological age-related changes, and linear regressions fitted to the data to calculate progression slopes (signal), slope SE (noise), and corresponding signal-to-noise ratios (SNR=slope÷SE). Linear regressions were also used to fit SAP global indices mean deviation (MD) and pattern standard deviation (PSD). RESULTS On average, progression slopes of PERG amplitude/phase were skewed toward negative values, their mean being significantly (P<0.01) different from zero. In contrast, mean slopes of SAP-MD and PSD were not significantly different from zero. SNRs were higher for PERG than SAP (P<0.01). A substantial number of eyes displayed significant (P<0.05) progression of PERG amplitude (15% to 20%) or PERG phase (16% to 25%). Fewer eyes displayed significant progression of SAP-MD (0% to 2%) or SAP-PSD (4% to 8%). CONCLUSIONS The PERG displayed clear longitudinal loss of signal (diminished amplitude, phase delay, or both) in a substantial number of eyes of patients, indicating progressive deterioration of retinal ganglion cell function. Progression of SAP global indices MD and PSD was found in a relatively smaller number of eyes. It remains to be established whether PERG progression has predictive value for developing visual dysfunction.
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Affiliation(s)
- Lori M Ventura
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Petrović M, Jovanović P, Trenkić Božinović M, Bojović L, Jolić M. POTENCIJALNA ULOGA VIZUELNO EVOCIRANIH POTENCIJALA I "PATTERN" ELEKTRORETINOGRAFIJE U DIJAGNOZI PRIMARNOG GLAUKOMA OTVORENOG UGLA. ACTA MEDICA MEDIANAE 2012. [DOI: 10.5633/amm.2012.0403s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Uva MG, Di Pietro M, Longo A, Lauretta K, Reibaldi M, Reibaldi A. Pattern ERG and RNFL thickness in hypertensive eyes with normal blue-yellow visual field. Graefes Arch Clin Exp Ophthalmol 2012; 251:839-45. [PMID: 22886095 DOI: 10.1007/s00417-012-2132-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To evaluate the transient pattern electroretinogram (t-PERG) and the retinal nerve fiber layer (RNFL) thickness in eyes with ocular hypertension (OH) and normal short-wavelength automated perimetry (SWAP). METHODS In 26 patients with bilateral OH with normal SWAP, and in 26 age and sex matched healthy controls, t-PERG recording and RNFL thickness measurement were performed. Mean deviation (MD) and pattern standard deviation (PSD) of a reliable full threshold 24-2 SWAP were considered. RNFL thickness was determined by OCT3. Monocular PERG were recorded by using a black and white checkerboard pattern (check size 0.9°, contrast 100 %, mean luminance 80 cd/m2) generated on a monitor and reversed in contrast (four reversals per second, 2 Hz) at a distance of 70 cm. Patients had optimal correction at viewing distance; no mydriatic or miotic eye drops were used. Silver/silver chloride skin electrodes were placed over the lower eyelids in the stimulated eye (active electrode) and in the patched eye (reference electrode); ground electrode was in the Fpz scalp. Peak-to peak amplitude of P50 (N35-P50) and N95 (P50-N95) waves, and implicit time of P50, were considered. RESULTS Compared to controls, in OH eyes, a reduction of N35-P50 amplitude (2.86 ± 1.49 vs. 3.77 ± 1.08 microvolts, -24.1 %, t-test p = 0.015), of average RNFL thickness (88 ± 11 vs. 96 ± 10 μm, -9.5 %, t-test p = 0.002), and of RNFL thickness in superior (p = 0.015) and inferior quadrant (p < 0.001), were found. Multivariate analysis showed that in OH eyes, N35-P50 amplitude was inversely related to intraocular pressure (IOP) (p = 0.001); no correlation was found between N35-P50 amplitude and MD, PSD, CCT or RNFL thickness. CONCLUSIONS In OH eyes, both PERG and RNFL thickness changes occur in hypertensive eyes with undamaged SWAP; the correlation of PERG amplitude with IOP, but not with RNFL thickness, suggests that such PERG changes are an effect of the IOP on retinal ganglion cells, rather than a sign of their loss.
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Affiliation(s)
- Maurizio G Uva
- Institute of Ophthalmology, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy
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Walshe TE, Leach LL, D'Amore PA. TGF-β signaling is required for maintenance of retinal ganglion cell differentiation and survival. Neuroscience 2011; 189:123-31. [PMID: 21664439 DOI: 10.1016/j.neuroscience.2011.05.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 04/11/2011] [Accepted: 05/11/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE To determine the role of TGF-β1 in the maintenance of retinal ganglion cell line (RGC-5) differentiation and integrity. METHODS RGC-5 cells were differentiated in media conditioned by human non-pigmented ciliary epithelial cells (HNPE) for 4 days before treatment with TGF-β1 for 24 h. Cells were examined for morphological changes and harvested for western blot and real-time PCR analysis. For study of apoptosis, differentiated RGC-5 cells were grown in serum-free medium for 24 h in the presence or absence of TGF-β1 and collected for Annexin V/Propidium iodide FACs analysis. The role of MAPK pathways in TGF-β1-dependent signaling was determined by treatment with specific inhibitors of ERK, JNK and p38. RESULTS Differentiation of RGC-5 cells in HNPE-conditioned media (CM) increased the neural cell markers, Brn-3c, NF-160, Thy1.2, Tau and PGP9.5. Treatment with TGF-β1 significantly increased the length of neurites extended by differentiated RGC-5s, concomitant with increased expression of NF-160 and PGP9.5, but not Brn-3c, Thy1.2 or Tau. TGF-β1 also decreased RGC-5 cell apoptosis in serum-free medium. p38 phosphorylation, but not smad2/3, JNK or ERK phosphorylation, was increased in TGF-β1 treated cells. Specific inhibition of p38 signaling reversed TGF-β1 induced neurite growth. CONCLUSIONS These findings demonstrate the induction of RGC-5 cell differentiation by HNPE-derived CM and illustrate a role for TGF-β1 in maintaining RGC-5 cell survival and promoting neurite outgrowth through p38 MAPK.
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Affiliation(s)
- T E Walshe
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute, 20 Staniford Street, Boston, MA 02114, USA
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