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Scarabosio A, Surico PL, Tereshenko V, Singh RB, Salati C, Spadea L, Caputo G, Parodi PC, Gagliano C, Winograd JM, Zeppieri M. Whole-eye transplantation: Current challenges and future perspectives. World J Transplant 2024; 14:95009. [PMID: 38947970 PMCID: PMC11212585 DOI: 10.5500/wjt.v14.i2.95009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/24/2024] [Accepted: 05/15/2024] [Indexed: 06/13/2024] Open
Abstract
Whole-eye transplantation emerges as a frontier in ophthalmology, promising a transformative approach to irreversible blindness. Despite advancements, formidable challenges persist. Preservation of donor eye viability post-enucleation necessitates meticulous surgical techniques to optimize retinal integrity and ganglion cell survival. Overcoming the inhibitory milieu of the central nervous system for successful optic nerve regeneration remains elusive, prompting the exploration of neurotrophic support and immunomodulatory interventions. Immunological tolerance, paramount for graft acceptance, confronts the distinctive immunogenicity of ocular tissues, driving research into targeted immunosuppression strategies. Ethical and legal considerations underscore the necessity for stringent standards and ethical frameworks. Interdisciplinary collaboration and ongoing research endeavors are imperative to navigate these complexities. Biomaterials, stem cell therapies, and precision immunomodulation represent promising avenues in this pursuit. Ultimately, the aim of this review is to critically assess the current landscape of whole-eye transplantation, elucidating the challenges and advancements while delineating future directions for research and clinical practice. Through concerted efforts, whole-eye transplantation stands to revolutionize ophthalmic care, offering hope for restored vision and enhanced quality of life for those afflicted with blindness.
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Affiliation(s)
- Anna Scarabosio
- Department of Plastic Surgery, University Hospital of Udine, Udine 33100, Italy
- Department of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
| | - Pier Luigi Surico
- Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, United States
| | - Vlad Tereshenko
- Department of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
| | - Rohan Bir Singh
- Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, United States
| | - Carlo Salati
- Department of Ophthalmology, University Hospital of Udine, Udine 33100, Italy
| | - Leopoldo Spadea
- Eye Clinic, Policlinico Umberto I, "Sapienza" University of Rome, Rome 00142, Italy
| | - Glenda Caputo
- Department of Plastic Surgery, University Hospital of Udine, Udine 33100, Italy
| | - Pier Camillo Parodi
- Department of Plastic Surgery, University Hospital of Udine, Udine 33100, Italy
| | - Caterina Gagliano
- Department of Medicine and Surgery, University of Enna "Kore", Enna 94100, Italy
- Eye Clinic Catania University San Marco Hospital, Viale Carlo Azeglio Ciampi 95121 Catania, Italy
| | - Jonathan M Winograd
- Department of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
| | - Marco Zeppieri
- Department of Ophthalmology, University Hospital of Udine, Udine 33100, Italy
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Palko SI, Benoit MR, Yao AY, Mohan R, Yan R. ER-stress response in retinal Müller glia occurs significantly earlier than amyloid pathology in the Alzheimer's mouse brain and retina. Glia 2024; 72:1067-1081. [PMID: 38497356 PMCID: PMC11006574 DOI: 10.1002/glia.24514] [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: 01/10/2023] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 03/19/2024]
Abstract
Alzheimer's Disease (AD) pathogenesis is thought to begin up to 20 years before cognitive symptoms appear, suggesting the need for more sensitive diagnostic biomarkers of AD. In this report, we demonstrated pathological changes in retinal Müller glia significantly earlier than amyloid pathology in AD mouse models. By utilizing the knock-in NLGF mouse model, we surprisingly discovered an increase in reticulon 3 (RTN3) protein levels in the NLGF retina as early as postnatal day 30 (P30). Despite RTN3 being a canonically neuronal protein, this increase was noted in the retinal Müller glia, confirmed by immunohistochemical characterization. Further unbiased transcriptomic assays of the P30 NLGF retina revealed that retinal Müller glia were the most sensitive responding cells in this mouse retina, compared with other cell types including photoreceptor cells and ganglion neurons. Pathway analyses of differentially expressed genes in glia cells showed activation of ER stress response via the upregulation of unfolded protein response (UPR) proteins such as ATF4 and CHOP. Early elevation of RTN3 in response to challenges by toxic Aβ likely facilitated UPR. Altogether, these findings suggest that Müller glia act as a sentinel for AD pathology in the retina and should aid for both intervention and diagnosis.
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Affiliation(s)
| | | | - Annie Y. Yao
- Department of Neuroscience, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Royce Mohan
- Department of Neuroscience, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Riqiang Yan
- Department of Neuroscience, University of Connecticut Health Center, Farmington CT 06030 USA
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Pan R, Ye C, Zhang Z, Kwapong WR, Wang R, Lu K, Liao L, Yan Y, Yang T, Cao L, Jiang S, Zhang X, Liu J, Tao W, Wu B. Distinct alterations of retinal structure between thalamic and extra-thalamic subcortical infarction patients: A cross-sectional and longitudinal study. CNS Neurosci Ther 2024; 30:e14543. [PMID: 38018655 PMCID: PMC11017429 DOI: 10.1111/cns.14543] [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: 07/27/2023] [Revised: 10/25/2023] [Accepted: 11/14/2023] [Indexed: 11/30/2023] Open
Abstract
AIMS Cerebrovascular lesions in the primary visual cortex, the lateral geniculate nucleus, and the optic tract have been associated with retinal neurodegeneration via the retrograde degeneration (RD) mechanism. We aimed to use optical coherence tomography (OCT) to assess the effects of the strategic single subcortical infarction (SSI) location on retinal neurodegeneration and its longitudinal impacts. METHODS Patients with SSI were enrolled and stratified by lesion location on cerebral MRI into the thalamic infarction group and extra-thalamic infarction group. Healthy controls from the native communities were also recruited. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) were quantified using OCT. Generalized estimating equation (GEE) models were used for cross-sectional analyses and linear mixed models for longitudinal analyses. P < 0.05 was considered statistically significant. RESULTS We included a total of 283 eyes from 149 SSI patients. Of these, 115 eyes of 60 patients with follow-up were included in the longitudinal analyses. Cross-sectionally, thalamic-infarction patients had reduced retinal thickness compared with extra-thalamic infarction patients after adjustment for age, gender, disease duration, and vascular risk factors (p = 0.026 for RNFL, and p = 0.026 for GCIPL). Longitudinally, SSI patients showed greater retinal thinning compared with healthy controls over time (p = 0.040 for RNFL, and p < 0.001 for GCIPL), and thalamic infarction patients exhibited faster rates of GCIPL thinning in comparison with extra-thalamic infarction patients (p < 0.001). CONCLUSION Our study demonstrates a distinct effect of subcortical infarction lesion site on the retina both at the early stage of disease and at the 1-year follow-up time. These results present evidence of significant associations between strategic infarction locations and retinal neurodegeneration. It may provide novel insights for further research on RD in stroke patients and ultimately facilitate individualized recovery therapeutic strategy.
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Affiliation(s)
- Ruosu Pan
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
- Center of Cerebrovascular DiseasesWest China Hospital, Sichuan UniversityChengduChina
| | - Chen Ye
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
- Center of Cerebrovascular DiseasesWest China Hospital, Sichuan UniversityChengduChina
| | - Zhimeng Zhang
- West China School of MedicineSichuan UniversityChengduChina
| | | | - Ruilin Wang
- Department of OphthalmologyWest China Hospital, Sichuan UniversityChengduChina
| | - Kun Lu
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Lanhua Liao
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Yuying Yan
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Tang Yang
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Le Cao
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Shuai Jiang
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Xuening Zhang
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
| | - Junfeng Liu
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
- Center of Cerebrovascular DiseasesWest China Hospital, Sichuan UniversityChengduChina
| | - Wendan Tao
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
- Center of Cerebrovascular DiseasesWest China Hospital, Sichuan UniversityChengduChina
| | - Bo Wu
- Department of NeurologyWest China Hospital, Sichuan UniversityChengduChina
- Center of Cerebrovascular DiseasesWest China Hospital, Sichuan UniversityChengduChina
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Perumal N, Yurugi H, Dahm K, Rajalingam K, Grus FH, Pfeiffer N, Manicam C. Proteome landscape and interactome of voltage-gated potassium channel 1.6 (Kv1.6) of the murine ophthalmic artery and neuroretina. Int J Biol Macromol 2024; 257:128464. [PMID: 38043654 DOI: 10.1016/j.ijbiomac.2023.128464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/14/2023] [Accepted: 11/25/2023] [Indexed: 12/05/2023]
Abstract
The voltage-gated potassium channel 1.6 (Kv1.6) plays a vital role in ocular neurovascular beds and exerts its modulatory functions via interaction with other proteins. However, the interactome and their potential roles remain unknown. Here, the global proteome landscape of the ophthalmic artery (OA) and neuroretina was mapped, followed by the determination of Kv1.6 interactome and validation of its functionality and cellular localization. Microfluorimetric analysis of intracellular [K+] and Western blot validated the native functionality and cellular expression of the recombinant Kv1.6 channel protein. A total of 54, 9 and 28 Kv1.6-interacting proteins were identified in the mouse OA and, retina of mouse and rat, respectively. The Kv1.6-protein partners in the OA, namely actin cytoplasmic 2, alpha-2-macroglobulin and apolipoprotein A-I, were implicated in the maintenance of blood vessel integrity by regulating integrin-mediated adhesion to extracellular matrix and Ca2+ flux. Many retinal protein interactors, particularly the ADP/ATP translocase 2 and cytoskeleton protein tubulin, were involved in endoplasmic reticulum stress response and cell viability. Three common interactors were found in all samples comprising heat shock cognate 71 kDa protein, Ig heavy constant gamma 1 and Kv1.6 channel. This foremost in-depth investigation enriched and identified the elusive Kv1.6 channel and, elucidated its complex interactome.
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Affiliation(s)
- Natarajan Perumal
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Hajime Yurugi
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Katrin Dahm
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Krishnaraj Rajalingam
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Franz H Grus
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Caroline Manicam
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany.
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Wang MD, Zhang S, Liu XY, Wang PP, Zhu YF, Zhu JR, Lv CS, Li SY, Liu SF, Wen L. Salvianolic acid B ameliorates retinal deficits in an early-stage Alzheimer's disease mouse model through downregulating BACE1 and Aβ generation. Acta Pharmacol Sin 2023; 44:2151-2168. [PMID: 37420104 PMCID: PMC10618533 DOI: 10.1038/s41401-023-01125-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/08/2023] [Indexed: 07/09/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with subtle onset, early diagnosis remains challenging. Accumulating evidence suggests that the emergence of retinal damage in AD precedes cognitive impairment, and may serve as a critical indicator for early diagnosis and disease progression. Salvianolic acid B (Sal B), a bioactive compound isolated from the traditional Chinese medicinal herb Salvia miltiorrhiza, has been shown promise in treating neurodegenerative diseases, such as AD and Parkinson's disease. In this study we investigated the therapeutic effects of Sal B on retinopathy in early-stage AD. One-month-old transgenic mice carrying five familial AD mutations (5×FAD) were treated with Sal B (20 mg·kg-1·d-1, i.g.) for 3 months. At the end of treatment, retinal function and structure were assessed, cognitive function was evaluated in Morris water maze test. We showed that 4-month-old 5×FAD mice displayed distinct structural and functional deficits in the retinas, which were significantly ameliorated by Sal B treatment. In contrast, untreated, 4-month-old 5×FAD mice did not exhibit cognitive impairment compared to wild-type mice. In SH-SY5Y-APP751 cells, we demonstrated that Sal B (10 μM) significantly decreased BACE1 expression and sorting into the Golgi apparatus, thereby reducing Aβ generation by inhibiting the β-cleavage of APP. Moreover, we found that Sal B effectively attenuated microglial activation and the associated inflammatory cytokine release induced by Aβ plaque deposition in the retinas of 5×FAD mice. Taken together, our results demonstrate that functional impairments in the retina occur before cognitive decline, suggesting that the retina is a valuable reference for early diagnosis of AD. Sal B ameliorates retinal deficits by regulating APP processing and Aβ generation in early AD, which is a potential therapeutic intervention for early AD treatment.
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Affiliation(s)
- Meng-Dan Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Shuo Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Xing-Yang Liu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Pan-Pan Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Yi-Fan Zhu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Jun-Rong Zhu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Chong-Shan Lv
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Shi-Ying Li
- Eye Institute of Xiamen University, Department of Ophthalmology, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China.
| | - Sui-Feng Liu
- Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361000, China.
| | - Lei Wen
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China.
- Xiamen Key Laboratory for TCM Dampness Disease, Neurology & Immunology Research, Department of Traditional Chinese Medicine, Xiang'an Hospital, School of Medicine, Xiamen University, Xiamen, 361102, China.
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Parameswarappa DC, Sheth J, Agarwal K. RETINAL CHANGES IN PORETTI-BOLTSHAUSER SYNDROME: RETINA AS A WINDOW TO THE BRAIN. Retin Cases Brief Rep 2023; 17:511-514. [PMID: 35671446 DOI: 10.1097/icb.0000000000001233] [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: 06/15/2023]
Abstract
PURPOSE LAMA 1 gene as a pathologic variant leading to cerebellar dysplasia and cysts, nonprogressive ataxia, language, and motor developmental delay without any muscular involvement was recently described as Poretti-Boltshauser syndrome (PBS). Ocular involvement is a common associated feature in this neurodegenerative disorder. In this case report, we describe the retinal changes associated with Poretti-Boltshauser syndrome. METHODS, PATIENT, AND RESULTS A 4-year-old female child presented with the progressive decreased vision for the past 6 to 8 months. Ophthalmic examination revealed mild myopia and ocular motor apraxia with retinal disruptions appearing as holes that were confined only to inner retinal layers. The child also had motor and speech developmental delays. Magnetic resonance imaging of the brain showed vermis hypoplasia with cerebellar dysgenesis and multiple cystic spaces in both cerebellar hemispheres. Whole exome sequencing revealed a homozygous pathogenic variant of exon 2-63 deletion in the LAMA 1 gene, which was confirmatory for Poretti-Boltshauser syndrome. CONCLUSION Oculomotor apraxia and retinal changes can lead to visual disturbances in Poretti-Boltshauser syndrome. Identification of these features and prompt rehabilitative measures can improve the quality of life of these children.
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Affiliation(s)
- Deepika C Parameswarappa
- Smt. Kanuri Santhamma Centre for Vitreo-Retinal Diseases, LV Prasad Eye Institute, Hyderabad, India; and
| | - Jenil Sheth
- Child Sight Institute, LV Prasad Eye Institute, Hyderabad, India
| | - Komal Agarwal
- Smt. Kanuri Santhamma Centre for Vitreo-Retinal Diseases, LV Prasad Eye Institute, Hyderabad, India; and
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Zhang L, Zhuang C, Wang Y, Wang H, Cui G, Guo J. Clinical Observation of Macular Superficial Capillary Plexus and Ganglion Cell Complex in Patients with Parkinson's Disease. Ophthalmic Res 2023; 66:1181-1190. [PMID: 37562366 PMCID: PMC10614441 DOI: 10.1159/000533158] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 07/04/2023] [Indexed: 08/12/2023]
Abstract
INTRODUCTION We investigated macular superficial capillary plexus (SCP) density and the thicknesses of the ganglion cell complex (GCC) in patients with Parkinson's disease (PD) and correlated them. We also observed the correlations between SCP density and clinical parameters of PD patients. The retina might be a novel biomarker of PD and will be useful in the future for the early diagnosis of PD and detecting disease progression. METHODS Seventy-four participants (38 patients with PD and 36 healthy controls) were recruited at the Affiliated Hospital of Xuzhou Medical University between January 2022 and June 2022 in this study. The macular SCP densities was measured by optical coherence tomography angiography (OCTA), and the GCC thickness was measured by optical coherence tomography (OCT). The parameters were compared between PD patients and healthy controls. The correlation between SCP and clinical parameters was tested. RESULTS Compared with the control group, PD patients showed reduced SCP densities in all areas of the macular region (parafovea-temporal: t = 3.053, p = 0.003; parafovea-superior: t = 3.680, p = 0.001; parafovea-nasal: t = 4.643, p < 0.001; parafovea-inferior: t = 2.254, p = 0.027; perifovea-temporal: t = 3.798, p < 0.001; perifovea-superior: t = 3.014, p = 0.004; perifovea-nasal: t = 2.948, p = 0.004; perifovea-inferior: t = 3.337, p = 0.021). The average GCC thickness in the PD patients was significantly reduced (t = 2.365, p = 0.021). There were positive correlations between the average GCC thickness and the SCP densities in most of the areas of the macular regions in PD patients (parafovea-temporal: r = 0.325, p = 0.005; parafovea-superior: r = 0.295, p = 0.011; parafovea-nasal: r = 0.335, p = 0.003; perifovea-superior: r = 0.362, p = 0.002; perifovea-nasal: r = 0.290, p = 0.012; perifovea-inferior: r = 0.333, p = 0.004). We found significant correlations between SCP densities and Hoehn and Yahr (H and Y) scales, UPDRS III scores, and MMSE scores. No significant correlation was observed between SCP density and PD disease duration (all p > 0.05). CONCLUSIONS We demonstrated that the macular SCP density was decreased, and the average GCC thickness was reduced in PD patients. The correlation between SCP density damage and GCC thinning also suggested that the retinal microvascular damage may be associated with retinal structural degeneration in PD patients. OCTA and OCT may be considered objective biomarkers for detecting microvascular impairment and neuronal damage in the early stages of PD in the future.
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Affiliation(s)
- Ling Zhang
- Department of Ophthalmology, Xuzhou Medical University, Xuzhou, China
| | - Chuchu Zhuang
- Department of Ophthalmology, Xuzhou Medical University, Xuzhou, China
| | - Yining Wang
- Department of Ophthalmology, Xuzhou Medical University, Xuzhou, China
| | - He Wang
- Department of Ophthalmology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Guiyun Cui
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Jianxin Guo
- Department of Ophthalmology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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The Role of Alpha-Synuclein Deposits in Parkinson's Disease: A Focus on the Human Retina. Int J Mol Sci 2023; 24:ijms24054391. [PMID: 36901822 PMCID: PMC10002434 DOI: 10.3390/ijms24054391] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative condition characterized by the progressive deterioration of dopaminergic neurons in the central and peripheral autonomous system and the intraneuronal cytoplasmic accumulation of misfolded α-synuclein. The clinical features are the classic triad of tremor, rigidity, and bradykinesia and a set of non-motor symptoms, including visual deficits. The latter seems to arise years before the onset of motor symptoms and reflects the course of brain disease. The retina, by virtue of its similarity to brain tissue, is an excellent site for the analysis of the known histopathological changes of PD that occur in the brain. Numerous studies conducted on animal and human models of PD have shown the presence of α-synuclein in retinal tissue. Spectral-domain optical coherence tomography (SD-OCT) could be a technique that enables the study of these retinal alterations in vivo. The objective of this review is to describe recent evidence on the accumulation of native or modified α-synuclein in the human retina of patients with PD and its effects on the retinal tissue evaluated through SD-OCT.
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Hilal S, Cheung CY, Wong TY, Schmetterer L, Chen C. Retinal parameters, cortical cerebral microinfarcts, and their interaction with cognitive impairment. Int J Stroke 2023; 18:70-77. [PMID: 35450485 DOI: 10.1177/17474930221097737] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Quantitative changes in retinal vessels and thinning of optic nerves have been associated with subclinical (atherosclerosis, inflammation) and clinical age-related brain pathologies (stroke and neurodegeneration). However, data on the association between both retinal vascular and neuronal parameters with cortical cerebral microinfarcts (CMIs) and how these factors jointly influence cognition are lacking. AIM We investigated the association of retinal vascular and neuronal changes with CMIs on 3 T MRI and explored their interaction with cognitive impairment in a memory-clinic population. METHODS A total of 538 participants were included. Retinal vascular parameters (caliber, tortuosity, and fractal dimension) were measured from retinal fundus photographs using a semi-automated computer-assisted program. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thicknesses were obtained from optical coherence tomography. Cortical CMIs were defined as hypointense on T1-weighted MRI, <5 mm in diameter and restricted to the cortex. Cognition was assessed using Clinical Dementia Rating Sum-of-Boxes (CDR-SoB) score and detailed neuropsychological test. Multivariable regression analysis was conducted adjusting for age, sex, hypertension, hyperlipidemia, diabetes mellitus, smoking, diagnosis, white matter hyperintensities volume, lacunes, and cerebral microbleeds. RESULTS Larger venular caliber (Rate ratios (RR): 1.15, 95% CI: 1.01-1.38, p = 0.014), increased venular fractal dimension (RR: 1.58, 95% CI: 1.31-1.91, p ⩽ 0.001), increased venular tortuosity (RR: 1.54, 95% CI: 1.35-1.75, p ⩽ 0.001), and thinner GC-IPL (RR: 1.24, 95% CI: 1.13-1.36, p ⩽ 0.001) were associated with CMI counts. Among individuals in highest tertile of retinal parameters, a significant interaction was observed between venular tortuosity (RR: 1.12, 95% CI: 1.02-1.22, p-interaction = 0.014) and GC-IPL (RR: 1.05, 95% CI: 1.01-1.11, p-interaction < 0.001) with CMIs on CDR-SoB. CONCLUSION Retinal vascular and neuronal parameters are associated with cortical CMIs, and persons with both pathologies are likely to have cognitive impairment. Further studies may be warranted to evaluate the clinical utility of retinal parameters and CMI in risk prediction for cognitive dysfunction.
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Affiliation(s)
- Saima Hilal
- Memory Aging and Cognition Center, National University Health System, Singapore, Singapore.,Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore, Singapore
| | - Carol Y Cheung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Tien Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Christopher Chen
- Memory Aging and Cognition Center, National University Health System, Singapore, Singapore.,Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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10
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Lee IO, Skuse DH, Constable PA, Marmolejo-Ramos F, Olsen LR, Thompson DA. The electroretinogram b-wave amplitude: a differential physiological measure for Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder. J Neurodev Disord 2022; 14:30. [PMID: 35524181 PMCID: PMC9077889 DOI: 10.1186/s11689-022-09440-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/12/2022] [Indexed: 12/02/2022] Open
Abstract
Background Attention Deficit Hyperactivity Disorder (ADHD) is the most prevalent childhood neurodevelopmental disorder. It shares some genetic risk with Autism Spectrum Disorder (ASD), and the conditions often occur together. Both are potentially associated with abnormal glutamate and GABA neurotransmission, which can be modelled by measuring the synaptic activity in the retina with an electroretinogram (ERG). Reduction of retinal responses in ASD has been reported, but little is known about retinal activity in ADHD. In this study, we compared the light-adapted ERGs of individuals with ADHD, ASD and controls to investigate whether retinal responses differ between these neurodevelopmental conditions. Methods Full field light-adapted ERGs were recorded from 15 ADHD, 57 ASD (without ADHD) and 59 control participants, aged from 5.4 to 27.3 years old. A Troland protocol was used with a random series of nine flash strengths from −0.367 to 1.204 log photopic cd.s.m−2. The time-to-peak and amplitude of the a- and b-waves and the parameters of the Photopic Negative Response (PhNR) were compared amongst the three groups of participants, using generalised estimating equations. Results Statistically significant elevations of the ERG b-wave amplitudes, PhNR responses and faster timings of the b-wave time-to-peak were found in those with ADHD compared with both the control and ASD groups. The greatest elevation in the b-wave amplitudes associated with ADHD were observed at 1.204 log phot cd.s.m−2 flash strength (p < .0001), at which the b-wave amplitude in ASD was significantly lower than that in the controls. Using this measure, ADHD could be distinguished from ASD with an area under the curve of 0.88. Conclusions The ERG b-wave amplitude appears to be a distinctive differential feature for both ADHD and ASD, which produced a reversed pattern of b-wave responses. These findings imply imbalances between glutamate and GABA neurotransmission which primarily regulate the b-wave formation. Abnormalities in the b-wave amplitude could provisionally serve as a biomarker for both neurodevelopmental conditions. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-022-09440-2.
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Affiliation(s)
- Irene O Lee
- Behavioural and Brain Sciences Unit, Population Policy and Practice Programme, UCL Great Ormond Street Institute of Child Health, University College London, London, UK.
| | - David H Skuse
- Behavioural and Brain Sciences Unit, Population Policy and Practice Programme, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Paul A Constable
- Caring Futures Institute, College of Nursing and Health Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Fernando Marmolejo-Ramos
- Centre for Change and Complexity in Learning, University of South Australia, Adelaide, Australia
| | - Ludvig R Olsen
- Department of Molecular Medicine (MOMA), Aarhus University, Aarhus, Denmark
| | - Dorothy A Thompson
- The Tony Kriss Visual Electrophysiology Unit, Clinical and Academic Department of Ophthalmology, Sight and Sound Centre, Great Ormond Street Hospital for Children NHS Trust, London, UK.,UCL Great Ormond Street Institute of Child Health, University College London, London, UK
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11
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Edwards G, Olson CG, Euritt CP, Koulen P. Molecular Mechanisms Underlying the Therapeutic Role of Vitamin E in Age-Related Macular Degeneration. Front Neurosci 2022; 16:890021. [PMID: 35600628 PMCID: PMC9114494 DOI: 10.3389/fnins.2022.890021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 03/21/2022] [Indexed: 12/31/2022] Open
Abstract
The eye is particularly susceptible to oxidative stress and disruption of the delicate balance between oxygen-derived free radicals and antioxidants leading to many degenerative diseases. Attention has been called to all isoforms of vitamin E, with α-tocopherol being the most common form. Though similar in structure, each is diverse in antioxidant activity. Preclinical reports highlight vitamin E’s influence on cell physiology and survival through several signaling pathways by activating kinases and transcription factors relevant for uptake, transport, metabolism, and cellular action to promote neuroprotective effects. In the clinical setting, population-based studies on vitamin E supplementation have been inconsistent at times and follow-up studies are needed. Nonetheless, vitamin E’s health benefits outweigh the controversies. The goal of this review is to recognize the importance of vitamin E’s role in guarding against gradual central vision loss observed in age-related macular degeneration (AMD). The therapeutic role and molecular mechanisms of vitamin E’s function in the retina, clinical implications, and possible toxicity are collectively described in the present review.
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12
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Altered retinal structure and function in Spinocerebellar ataxia type 3. Neurobiol Dis 2022; 170:105774. [DOI: 10.1016/j.nbd.2022.105774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 01/13/2023] Open
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13
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Salbaum KA, Shelton ER, Serwane F. Retina organoids: Window into the biophysics of neuronal systems. BIOPHYSICS REVIEWS 2022; 3:011302. [PMID: 38505227 PMCID: PMC10903499 DOI: 10.1063/5.0077014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/16/2021] [Indexed: 03/21/2024]
Abstract
With a kind of magnetism, the human retina draws the eye of neuroscientist and physicist alike. It is attractive as a self-organizing system, which forms as a part of the central nervous system via biochemical and mechanical cues. The retina is also intriguing as an electro-optical device, converting photons into voltages to perform on-the-fly filtering before the signals are sent to our brain. Here, we consider how the advent of stem cell derived in vitro analogs of the retina, termed retina organoids, opens up an exploration of the interplay between optics, electrics, and mechanics in a complex neuronal network, all in a Petri dish. This review presents state-of-the-art retina organoid protocols by emphasizing links to the biochemical and mechanical signals of in vivo retinogenesis. Electrophysiological recording of active signal processing becomes possible as retina organoids generate light sensitive and synaptically connected photoreceptors. Experimental biophysical tools provide data to steer the development of mathematical models operating at different levels of coarse-graining. In concert, they provide a means to study how mechanical factors guide retina self-assembly. In turn, this understanding informs the engineering of mechanical signals required to tailor the growth of neuronal network morphology. Tackling the complex developmental and computational processes in the retina requires an interdisciplinary endeavor combining experiment and theory, physics, and biology. The reward is enticing: in the next few years, retina organoids could offer a glimpse inside the machinery of simultaneous cellular self-assembly and signal processing, all in an in vitro setting.
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Affiliation(s)
| | - Elijah R. Shelton
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany
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14
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Multimodal brain and retinal imaging of dopaminergic degeneration in Parkinson disease. Nat Rev Neurol 2022; 18:203-220. [PMID: 35177849 DOI: 10.1038/s41582-022-00618-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2022] [Indexed: 12/12/2022]
Abstract
Parkinson disease (PD) is a progressive disorder characterized by dopaminergic neurodegeneration in the brain. The development of parkinsonism is preceded by a long prodromal phase, and >50% of dopaminergic neurons can be lost from the substantia nigra by the time of the initial diagnosis. Therefore, validation of in vivo imaging biomarkers for early diagnosis and monitoring of disease progression is essential for future therapeutic developments. PET and single-photon emission CT targeting the presynaptic terminals of dopaminergic neurons can be used for early diagnosis by detecting axonal degeneration in the striatum. However, these techniques poorly differentiate atypical parkinsonian syndromes from PD, and their availability is limited in clinical settings. Advanced MRI in which pathological changes in the substantia nigra are visualized with diffusion, iron-sensitive susceptibility and neuromelanin-sensitive sequences potentially represents a more accessible imaging tool. Although these techniques can visualize the classic degenerative changes in PD, they might be insufficient for phenotyping or prognostication of heterogeneous aspects of PD resulting from extranigral pathologies. The retina is an emerging imaging target owing to its pathological involvement early in PD, which correlates with brain pathology. Retinal optical coherence tomography (OCT) is a non-invasive technique to visualize structural changes in the retina. Progressive parafoveal thinning and fovea avascular zone remodelling, as revealed by OCT, provide potential biomarkers for early diagnosis and prognostication in PD. As we discuss in this Review, multimodal imaging of the substantia nigra and retina is a promising tool to aid diagnosis and management of PD.
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15
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Little K, Llorián-Salvador M, Scullion S, Hernández C, Simó-Servat O, Del Marco A, Bosma E, Vargas-Soria M, Carranza-Naval MJ, Van Bergen T, Galbiati S, Viganò I, Musi CA, Schlingemann R, Feyen J, Borsello T, Zerbini G, Klaassen I, Garcia-Alloza M, Simó R, Stitt AW. Common pathways in dementia and diabetic retinopathy: understanding the mechanisms of diabetes-related cognitive decline. Trends Endocrinol Metab 2022; 33:50-71. [PMID: 34794851 DOI: 10.1016/j.tem.2021.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/06/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022]
Abstract
Type 2 diabetes (T2D) is associated with multiple comorbidities, including diabetic retinopathy (DR) and cognitive decline, and T2D patients have a significantly higher risk of developing Alzheimer's disease (AD). Both DR and AD are characterized by a number of pathological mechanisms that coalesce around the neurovascular unit, including neuroinflammation and degeneration, vascular degeneration, and glial activation. Chronic hyperglycemia and insulin resistance also play a significant role, leading to activation of pathological mechanisms such as increased oxidative stress and the accumulation of advanced glycation end-products (AGEs). Understanding these common pathways and the degree to which they occur simultaneously in the brain and retina during diabetes will provide avenues to identify T2D patients at risk of cognitive decline.
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Affiliation(s)
- Karis Little
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - María Llorián-Salvador
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Sarah Scullion
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Cristina Hernández
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain
| | - Olga Simó-Servat
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain
| | - Angel Del Marco
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Esmeralda Bosma
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands
| | - Maria Vargas-Soria
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Maria Jose Carranza-Naval
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | | | - Silvia Galbiati
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Ilaria Viganò
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Clara Alice Musi
- Università Degli Studi di Milano and Istituto di Ricerche Farmacologiche Mario Negri- IRCCS, Milano, Italy
| | - Reiner Schlingemann
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | | | - Tiziana Borsello
- Università Degli Studi di Milano and Istituto di Ricerche Farmacologiche Mario Negri- IRCCS, Milano, Italy
| | - Gianpaolo Zerbini
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Ingeborg Klaassen
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Rafael Simó
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain.
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK.
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16
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Veys L, Devroye J, Lefevere E, Cools L, Vandenabeele M, De Groef L. Characterizing the Retinal Phenotype of the Thy1-h[A30P]α-syn Mouse Model of Parkinson's Disease. Front Neurosci 2021; 15:726476. [PMID: 34557068 PMCID: PMC8452874 DOI: 10.3389/fnins.2021.726476] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/19/2021] [Indexed: 12/30/2022] Open
Abstract
Despite decades of research, disease-modifying treatments of Parkinson’s disease (PD), the second most common neurodegenerative disease worldwide, remain out of reach. One of the reasons for this treatment gap is the incomplete understanding of how misfolded alpha-synuclein (α-syn) contributes to PD pathology. The retina, as an integral part of the central nervous system, recapitulates the PD disease processes that are typically seen in the brain, and retinal manifestations have emerged as prodromal symptoms of the disease. The timeline of PD manifestations in the visual system, however, is not fully elucidated and the underlying mechanisms are obscure. This highlights the need for new studies investigating retinal pathology, in order to propel its use as PD biomarker, and to develop validated research models to investigate PD pathogenesis. The present study pioneers in characterizing the retina of the Thy1-h[A30P]α-syn PD transgenic mouse model. We demonstrate widespread α-syn accumulation in the inner retina of these mice, of which a proportion is phosphorylated yet not aggregated. This α-syn expression coincides with inner retinal atrophy due to postsynaptic degeneration. We also reveal abnormal retinal electrophysiological responses. Absence of selective loss of melanopsin retinal ganglion cells or dopaminergic amacrine cells and inflammation indicates that the retinal manifestations in these transgenic mice diverge from their brain phenotype, and questions the specific cellular or molecular alterations that underlie retinal pathology in this PD mouse model. Nevertheless, the observed α-syn accumulation, synapse loss and functional deficits suggest that the Thy1-h[A30P]α-syn retina mimics some of the features of prodromal PD, and thus may provide a window to monitor and study the preclinical/prodromal stages of PD, PD-associated retinal disease processes, as well as aid in retinal biomarker discovery and validation.
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Affiliation(s)
- Lien Veys
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Joyce Devroye
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Evy Lefevere
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lien Cools
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Marjan Vandenabeele
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lies De Groef
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
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17
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Vandenabeele M, Veys L, Lemmens S, Hadoux X, Gelders G, Masin L, Serneels L, Theunis J, Saito T, Saido TC, Jayapala M, De Boever P, De Strooper B, Stalmans I, van Wijngaarden P, Moons L, De Groef L. The App NL-G-F mouse retina is a site for preclinical Alzheimer's disease diagnosis and research. Acta Neuropathol Commun 2021; 9:6. [PMID: 33407903 PMCID: PMC7788955 DOI: 10.1186/s40478-020-01102-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/13/2022] Open
Abstract
In this study, we report the results of a comprehensive phenotyping of the retina of the AppNL-G-F mouse. We demonstrate that soluble Aβ accumulation is present in the retina of these mice early in life and progresses to Aβ plaque formation by midlife. This rising Aβ burden coincides with local microglia reactivity, astrogliosis, and abnormalities in retinal vein morphology. Electrophysiological recordings revealed signs of neuronal dysfunction yet no overt neurodegeneration was observed and visual performance outcomes were unaffected in the AppNL-G-F mouse. Furthermore, we show that hyperspectral imaging can be used to quantify retinal Aβ, underscoring its potential as a biomarker for AD diagnosis and monitoring. These findings suggest that the AppNL-G-F retina mimics the early, preclinical stages of AD, and, together with retinal imaging techniques, offers unique opportunities for drug discovery and fundamental research into preclinical AD.
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Affiliation(s)
- Marjan Vandenabeele
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lien Veys
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Sophie Lemmens
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Xavier Hadoux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
| | - Géraldine Gelders
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Luca Masin
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lutgarde Serneels
- Leuven Brain Institute, Leuven, Belgium
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Jan Theunis
- Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Interuniversity Microelectronics Centre (Imec), Leuven, Belgium
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
| | - Murali Jayapala
- Interuniversity Microelectronics Centre (Imec), Leuven, Belgium
| | - Patrick De Boever
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
- Center of Environmental Sciences, Hasselt University, Diepenbeek, Belgium
- Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Bart De Strooper
- Leuven Brain Institute, Leuven, Belgium
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ingeborg Stalmans
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Peter van Wijngaarden
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium.
- Leuven Brain Institute, Leuven, Belgium.
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18
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Retina as a Model to Study In Vivo Transmission of α-Synuclein in the A53T Mouse Model of Parkinson's Disease. Methods Mol Biol 2021; 2224:75-85. [PMID: 33606207 DOI: 10.1007/978-1-0716-1008-4_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Parkinson's disease is a neurodegenerative disorder characterized by accumulation of misfolded α-synuclein within the central nervous system (CNS). Retinal manifestations have been widely described as a prodromal symptom; however, we have a limited understanding of the retinal pathology associated with Parkinson's disease. The strong similarities between the retina and the brain and the accessibility of the retina has potentiated studies to investigate retinal pathology in an effort to identify biomarkers for early detection, as well as for monitoring the progression of disease and efficacy of therapies as they become available. Here, we discuss a study conducted using a transgenic mouse model of Parkinson's disease (TgM83, expressing human α-synuclein containing the familial PD-associated A53T mutation) to demonstrate the effect of the A53T α-synuclein mutation on the retina. Additionally, we show that "seeding" with brain homogenates from clinically ill TgM83 mice accelerates the accumulation of retinal α-synuclein. The work described in this chapter provides insight into retinal changes associated with Parkinson's disease and identifies retinal indicators of Parkinson's disease pathogenesis that could serve as potential biomarkers for early detection.
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19
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Lemmens S, Van Craenendonck T, Van Eijgen J, De Groef L, Bruffaerts R, de Jesus DA, Charle W, Jayapala M, Sunaric-Mégevand G, Standaert A, Theunis J, Van Keer K, Vandenbulcke M, Moons L, Vandenberghe R, De Boever P, Stalmans I. Combination of snapshot hyperspectral retinal imaging and optical coherence tomography to identify Alzheimer's disease patients. Alzheimers Res Ther 2020; 12:144. [PMID: 33172499 PMCID: PMC7654576 DOI: 10.1186/s13195-020-00715-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/22/2020] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The eye offers potential for the diagnosis of Alzheimer's disease (AD) with retinal imaging techniques being explored to quantify amyloid accumulation and aspects of neurodegeneration. To assess these changes, this proof-of-concept study combined hyperspectral imaging and optical coherence tomography to build a classification model to differentiate between AD patients and controls. METHODS In a memory clinic setting, patients with a diagnosis of clinically probable AD (n = 10) or biomarker-proven AD (n = 7) and controls (n = 22) underwent non-invasive retinal imaging with an easy-to-use hyperspectral snapshot camera that collects information from 16 spectral bands (460-620 nm, 10-nm bandwidth) in one capture. The individuals were also imaged using optical coherence tomography for assessing retinal nerve fiber layer thickness (RNFL). Dedicated image preprocessing analysis was followed by machine learning to discriminate between both groups. RESULTS Hyperspectral data and retinal nerve fiber layer thickness data were used in a linear discriminant classification model to discriminate between AD patients and controls. Nested leave-one-out cross-validation resulted in a fair accuracy, providing an area under the receiver operating characteristic curve of 0.74 (95% confidence interval [0.60-0.89]). Inner loop results showed that the inclusion of the RNFL features resulted in an improvement of the area under the receiver operating characteristic curve: for the most informative region assessed, the average area under the receiver operating characteristic curve was 0.70 (95% confidence interval [0.55, 0.86]) and 0.79 (95% confidence interval [0.65, 0.93]), respectively. The robust statistics used in this study reduces the risk of overfitting and partly compensates for the limited sample size. CONCLUSIONS This study in a memory-clinic-based cohort supports the potential of hyperspectral imaging and suggests an added value of combining retinal imaging modalities. Standardization and longitudinal data on fully amyloid-phenotyped cohorts are required to elucidate the relationship between retinal structure and cognitive function and to evaluate the robustness of the classification model.
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Affiliation(s)
- Sophie Lemmens
- Department of Ophthalmology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurosciences, Research Group Ophthalmology, KU Leuven, Biomedical Sciences Group, Herestraat 49, 3000 Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
| | - Toon Van Craenendonck
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
| | - Jan Van Eijgen
- Department of Ophthalmology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurosciences, Research Group Ophthalmology, KU Leuven, Biomedical Sciences Group, Herestraat 49, 3000 Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, 3000 Leuven, Belgium
| | - Rose Bruffaerts
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Danilo Andrade de Jesus
- Department of Neurosciences, Research Group Ophthalmology, KU Leuven, Biomedical Sciences Group, Herestraat 49, 3000 Leuven, Belgium
| | | | | | - Gordana Sunaric-Mégevand
- Clinical Research Center, Mémorial A. de Rothschild, 22 Chemin Beau Soleil, 1208 Geneva, Switzerland
| | - Arnout Standaert
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
| | - Jan Theunis
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
| | - Karel Van Keer
- Department of Ophthalmology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurosciences, Research Group Ophthalmology, KU Leuven, Biomedical Sciences Group, Herestraat 49, 3000 Leuven, Belgium
| | - Mathieu Vandenbulcke
- Division of Psychiatry, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, 3000 Leuven, Belgium
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
- Alzheimer Research Center KU Leuven, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Patrick De Boever
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang 200, 2400 Mol, Belgium
- Hasselt University, Center of Environmental Sciences, Agoralaan, 3590 Diepenbeek, Belgium
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Ingeborg Stalmans
- Department of Ophthalmology, University Hospitals UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Neurosciences, Research Group Ophthalmology, KU Leuven, Biomedical Sciences Group, Herestraat 49, 3000 Leuven, Belgium
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20
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Karaca I, Demirkılınç Biler E, Palamar M, Özbaran B, Üretmen Ö. Stereoacuity, Fusional Vergence Amplitudes, and Refractive Errors Prior to Treatment in Patients with Attention-Deficit Hyperactivity Disorder. Turk J Ophthalmol 2020; 50:15-19. [PMID: 32166943 PMCID: PMC7086097 DOI: 10.4274/tjo.galenos.2019.17802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objectives: To evaluate stereoacuity, fusional vergence amplitudes, and refractive errors in patients with attention-deficit hyperactivity disorder (ADHD). Materials and Methods: Twenty-three patients who were newly diagnosed as having ADHD and had not started medication, and 48 children without ADHD were included. Retrospective data analysis of comprehensive eye examination, stereoacuity, and fusional vergence amplitudes of the patients were performed. Results: The mean age at ADHD diagnosis was 10.68±2.34 (7-16) years in the ADHD group (14 male, 9 female) and 12.23±2.16 (7-15) years in the control group (25 male, 23 female) patients (p=0.605). The mean stereoacuity was 142.14±152.65 (15-480) sec/arc in patients with ADHD and 46.3±44.11 (15-240) sec/arc in the control group (p<0.001). For ADHD patients, the mean convergence and divergence amplitudes at distance were 19.87±8.40 (6 to 38) prism diopter (PD) and -9.09±-4.34 (-4 to -25) PD, and 37.30±12.81 (14 to 70) PD and -13.13±-3.45 (-4 to -20) PD at near, respectively. The mean cycloplegic spherical equivalent was 1.06±1.13 (-1 to 4.63) diopter in ADHD patients, with 6 patients having significant refractive errors (hyperopia in 4 patients, astigmatism in 2 patients). There were no significant differences between groups in terms of spherical equivalents (p=0.358) or convergence and divergence amplitudes at distance (p=0.289 and p=0.492, respectively) or near (p=0.452 and p=0.127, respectively). Conclusion: Fusional vergence amplitudes did not present significant difference, while the mean value of stereoacuity was significantly lower in newly diagnosed ADHD patients prior to treatment.
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Affiliation(s)
- Irmak Karaca
- Ege University Faculty of Medicine, Department of Ophthalmology, İzmir, Turkey
| | | | - Melis Palamar
- Ege University Faculty of Medicine, Department of Ophthalmology, İzmir, Turkey
| | - Burcu Özbaran
- Ege University Faculty of Medicine, Department of Child and Adolescent Psychiatry, İzmir, Turkey
| | - Önder Üretmen
- Ege University Faculty of Medicine, Department of Ophthalmology, İzmir, Turkey
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21
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Retinal biomarkers and pharmacological targets for Hermansky-Pudlak syndrome 7. Sci Rep 2020; 10:3972. [PMID: 32132582 PMCID: PMC7055265 DOI: 10.1038/s41598-020-60931-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 02/19/2020] [Indexed: 01/24/2023] Open
Abstract
Deletion of dystrobrevin binding protein 1 has been linked to Hermansky-Pudlak syndrome type 7 (HPS-7), a rare disease characterized by oculocutaneous albinism and retinal dysfunction. We studied dysbindin-1 null mutant mice (Dys−/−) to shed light on retinal neurodevelopment defects in HPS-7. We analyzed the expression of a focused set of miRNAs in retina of wild type (WT), Dys+/− and Dys−/− mice. We also investigated the retinal function of these mice through electroretinography (ERG). We found that miR-101-3p, miR-137, miR-186-5p, miR-326, miR-382-5p and miR-876-5p were up-regulated in Dys−/−mice retina. Dys−/− mice showed significant increased b-wave in ERG, compared to WT mice. Bioinformatic analysis highlighted that dysregulated miRNAs target synaptic plasticity and dopaminergic signaling pathways, affecting retinal functions of Dys−/− mice. Overall, the data indicate potential mechanisms in retinal neurodevelopment of Dys−/− mice, which may have translational significance in HSP-7 patients, both in terms of diagnostic/prognostic biomarkers and novel pharmacological targets.
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22
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O'Hara DM, Kalia SK, Kalia LV. Methods for detecting toxic α-synuclein species as a biomarker for Parkinson's disease. Crit Rev Clin Lab Sci 2020; 57:291-307. [PMID: 32116096 DOI: 10.1080/10408363.2019.1711359] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the accumulation of α-synuclein (α-syn) into insoluble aggregates known as Lewy bodies and Lewy neurites in the brain. However, prior to the formation of these large aggregates, α-syn forms oligomers and small fibrils, which are believed to be the pathogenic species leading to the death of neurons in the substantia nigra in disease. The majority of aggregated α-syn is phosphorylated, and it is thought that this post-translational modification may be critical in disease pathogenesis. Thus, early detection of the toxic forms of α-syn may provide a window of opportunity for an intervention to halt or slow the progression of neurodegeneration in PD. Expression of α-syn is not restricted to the central nervous system and the protein can be found elsewhere, including bodily fluids and peripheral tissues. This review will examine current methods for detecting toxic forms of α-syn in accessible biospecimens and outline emerging techniques that may provide reliable identification of biomarkers for PD.
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Affiliation(s)
- Darren M O'Hara
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Suneil K Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Department of Surgery, Division of Neurosurgery, University of Toronto, Toronto, Canada
| | - Lorraine V Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Department of Medicine, Division of Neurology, University of Toronto, Toronto, Canada.,Department of Medicine, Division of Neurology, Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, University Health Network, Toronto, Canada.,Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
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23
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Lemmens S, Devulder A, Van Keer K, Bierkens J, De Boever P, Stalmans I. Systematic Review on Fractal Dimension of the Retinal Vasculature in Neurodegeneration and Stroke: Assessment of a Potential Biomarker. Front Neurosci 2020; 14:16. [PMID: 32116491 PMCID: PMC7025576 DOI: 10.3389/fnins.2020.00016] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/08/2020] [Indexed: 01/23/2023] Open
Abstract
Introduction: Ocular manifestations in several neurological pathologies accentuate the strong relationship between the eye and the brain. Retinal alterations in particular can serve as surrogates for cerebral changes. Offering a “window to the brain,” the transparent eye enables non-invasive imaging of these changes in retinal structure and vasculature. Fractal dimension (FD) reflects the overall complexity of the retinal vasculature. Changes in FD could reflect subtle changes in the cerebral vasculature that correspond to preclinical stages of neurodegenerative diseases. In this review, the potential of this retinal vessel metric to serve as a biomarker in neurodegeneration and stroke will be explored. Methods: A literature search was conducted, following the PRISMA Statement 2009 criteria, in four large bibliographic databases (Pubmed, Embase, Web Of Science and Cochrane Library) up to 12 October 2019. Articles have been included based upon their relevance. Wherever possible, level of evidence (LOE) has been assessed by means of the Oxford Centre for Evidence-based Medicine Level of Evidence classification. Results: Twenty-one studies were included for qualitative synthesis. We performed a narrative synthesis and produced summary tables of findings of included papers because methodological heterogeneity precluded a meta-analysis. A significant association was found between decreased FD and neurodegenerative disease, mainly addressing cognitive impairment (CI) and dementia. In acute, subacute as well as chronic settings, decreased FD seems to be associated with stroke. Differences in FD between subtypes of ischemic stroke remain unclear. Conclusions: This review provides a summary of the scientific literature regarding the association between retinal FD and neurodegenerative disease and stroke. Central pathology is associated with a decreased FD, as a measure of microvascular network complexity. As retinal FD reflects the global integrity of the cerebral microvasculature, it is an attractive parameter to explore. Despite obvious concerns, mainly due to a lack of methodological standardization, retinal FD remains a promising non-invasive and low-cost diagnostic biomarker for neurodegenerative and cerebrovascular disease. Before FD can be implemented in clinic as a diagnostic biomarker, the research community should strive for uniformization and standardization.
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Affiliation(s)
- Sophie Lemmens
- Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium.,Research Group Ophthalmology, Biomedical Science Group, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Health Unit, VITO (Flemish Institute for Technological Research), Mol, Belgium
| | - Astrid Devulder
- Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium.,Research Group Ophthalmology, Biomedical Science Group, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Karel Van Keer
- Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium.,Research Group Ophthalmology, Biomedical Science Group, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Johan Bierkens
- Health Unit, VITO (Flemish Institute for Technological Research), Mol, Belgium
| | - Patrick De Boever
- Health Unit, VITO (Flemish Institute for Technological Research), Mol, Belgium.,Centre of Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Ingeborg Stalmans
- Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium.,Research Group Ophthalmology, Biomedical Science Group, Department of Neurosciences, KU Leuven, Leuven, Belgium
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24
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Lee J, Ahn J, Oh S, Shin JY, Kim YK, Nam H, Jeon B. Retina Thickness as a Marker of Neurodegeneration in Prodromal Lewy Body Disease. Mov Disord 2019; 35:349-354. [DOI: 10.1002/mds.27914] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/02/2019] [Accepted: 10/06/2019] [Indexed: 12/16/2022] Open
Affiliation(s)
- Jee‐Young Lee
- Department of Neurology Seoul Metropolitan Government‐Seoul National University Boramae Medical Center and Seoul National University College of Medicine Seoul Republic of Korea
| | - Jeeyun Ahn
- Department of Ophthalmology Seoul Metropolitan Government‐Seoul National University Boramae Medical Center and Seoul National University College of Medicine Seoul Republic of Korea
| | - Sohee Oh
- Department of Biomedical Statistics Seoul Metropolitan Government‐Seoul National University Boramae Medical Center Seoul Republic of Korea
| | - Joo Young Shin
- Department of Ophthalmology Seoul Metropolitan Government‐Seoul National University Boramae Medical Center and Seoul National University College of Medicine Seoul Republic of Korea
| | - Yu Kyeong Kim
- Department of Nuclear Medicine Seoul Metropolitan Government‐Seoul National University Boramae Medical Center and Seoul National University College of Medicine Seoul Republic of Korea
| | - Hyunwoo Nam
- Department of Neurology Seoul Metropolitan Government‐Seoul National University Boramae Medical Center and Seoul National University College of Medicine Seoul Republic of Korea
| | - Beomseok Jeon
- Department of Neurology Seoul National University Hospital and Seoul National University College of Medicine Seoul Republic of Korea
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25
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Geeraerts E, Claes M, Dekeyster E, Salinas-Navarro M, De Groef L, Van den Haute C, Scheyltjens I, Baekelandt V, Arckens L, Moons L. Optogenetic Stimulation of the Superior Colliculus Confers Retinal Neuroprotection in a Mouse Glaucoma Model. J Neurosci 2019; 39:2313-2325. [PMID: 30655352 PMCID: PMC6433760 DOI: 10.1523/jneurosci.0872-18.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 11/15/2018] [Accepted: 12/29/2018] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGCs) in the eye, which ultimately results in visual impairment or even blindness. Because current therapies often fail to halt disease progression, there is an unmet need for novel neuroprotective therapies to support RGC survival. Various research lines suggest that visual target centers in the brain support RGC functioning and survival. Here, we explored whether increasing neuronal activity in one of these projection areas could improve survival of RGCs in a mouse glaucoma model. Prolonged activation of an important murine RGC target area, the superior colliculus (SC), was established via a novel optogenetic stimulation paradigm. By leveraging the unique channel kinetics of the stabilized step function opsin (SSFO), protracted stimulation of the SC was achieved with only a brief light pulse. SSFO-mediated collicular stimulation was confirmed by immunohistochemistry for the immediate-early gene c-Fos and behavioral tracking, which both demonstrated consistent neuronal activity upon repeated stimulation. Finally, the neuroprotective potential of optogenetic collicular stimulation was investigated in mice of either sex subjected to a glaucoma model and a 63% reduction in RGC loss was found. This work describes a new paradigm for optogenetic collicular stimulation and a first demonstration that increasing target neuron activity can increase survival of the projecting neurons.SIGNIFICANCE STATEMENT Despite glaucoma being a leading cause of blindness and visual impairment worldwide, no curative therapies exist. This study describes a novel paradigm to reduce retinal ganglion cell (RGC) degeneration underlying glaucoma. Building on previous observations that RGC survival is supported by the target neurons to which they project and using an innovative optogenetic approach, we increased neuronal activity in the mouse superior colliculus, a main projection target of rodent RGCs. This proved to be efficient in reducing RGC loss in a glaucoma model. Our findings establish a new optogenetic paradigm for target stimulation and encourage further exploration of the molecular signaling pathways mediating retrograde neuroprotective communication.
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Affiliation(s)
- Emiel Geeraerts
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Eline Dekeyster
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Manuel Salinas-Navarro
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Chris Van den Haute
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
- Viral Vector Core Leuven, KU Leuven, 3000 Leuven, Belgium, and
| | - Isabelle Scheyltjens
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology; KU Leuven, 3000 Leuven, Belgium
| | - Veerle Baekelandt
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Lutgarde Arckens
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology; KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium,
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
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26
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Veys L, Vandenabeele M, Ortuño-Lizarán I, Baekelandt V, Cuenca N, Moons L, De Groef L. Retinal α-synuclein deposits in Parkinson's disease patients and animal models. Acta Neuropathol 2019; 137:379-395. [PMID: 30721408 DOI: 10.1007/s00401-018-01956-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/22/2018] [Accepted: 12/22/2018] [Indexed: 12/21/2022]
Abstract
Despite decades of research, accurate diagnosis of Parkinson's disease remains a challenge, and disease-modifying treatments are still lacking. Research into the early (presymptomatic) stages of Parkinson's disease and the discovery of novel biomarkers is of utmost importance to reduce this burden and to come to a more accurate diagnosis at the very onset of the disease. Many have speculated that non-motor symptoms could provide a breakthrough in the quest for early biomarkers of Parkinson's disease, including the visual disturbances and retinal abnormalities that are seen in the majority of Parkinson's disease patients. An expanding number of clinical studies have investigated the use of in vivo assessments of retinal structure, electrophysiological function, and vision-driven tasks as novel means for identifying patients at risk that need further neurological examination and for longitudinal follow-up of disease progression in Parkinson's disease patients. Often, the results of these studies have been interpreted in relation to α-synuclein deposits and dopamine deficiency in the retina, mirroring the defining pathological features of Parkinson's disease in the brain. To better understand the visual defects seen in Parkinson's disease patients and to propel the use of retinal changes as biomarkers for Parkinson's disease, however, more conclusive neuropathological evidence for the presence of retinal α-synuclein aggregates, and its relation to the cerebral α-synuclein burden, is urgently needed. This review provides a comprehensive and critical overview of the research conducted to unveil α-synuclein aggregates in the retina of Parkinson's disease patients and animal models, and thereby aims to aid the ongoing discussion about the potential use of the retinal changes and/or visual symptoms as biomarkers for Parkinson's disease.
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27
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Vancamp P, Bourgeois NMA, Houbrechts AM, Darras VM. Knockdown of the thyroid hormone transporter MCT8 in chicken retinal precursor cells hampers early retinal development and results in a shift towards more UV/blue cones at the expense of green/red cones. Exp Eye Res 2018; 178:135-147. [PMID: 30273578 DOI: 10.1016/j.exer.2018.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/21/2018] [Accepted: 09/27/2018] [Indexed: 12/19/2022]
Abstract
Thyroid hormones (THs) play a crucial role in coordinating brain development in vertebrates. They fine-tune processes like cell proliferation, migration, and differentiation mainly by regulating the transcriptional activity of many essential genes. Regulators of TH availability thereby define the cellular concentration of the bioactive 3,5,3'-triiodothyronine, which binds to nuclear TH receptors. One important regulator, the monocarboxylate transporter 8 (MCT8), facilitates cellular TH uptake and is known to be necessary for correct brain development, but data on its potential role during retinal development is lacking. The retinal cyto-architecture has been conserved throughout vertebrate evolution, and we used the chicken embryo to study the need for MCT8 during retinal development. Its external development allows easy manipulation, and MCT8 is abundantly expressed in the retina from early stages onwards. We induced MCT8 knockdown by electroporating a pRFP-MCT8-RNAi vector into the retinal precursor cells (RPCs) at embryonic day 4 (E4), and studied the consequences for early (E6) and late (E18) retinal development. The empty pRFP-RNAi vector was used as a control. RPC proliferation was reduced at E6. This resulted in cellular hypoplasia and a thinner retina at E18 where mainly photoreceptors and horizontal cells were lost, the two predominant cell types that are born around the stage of electroporation. At E6, differentiation into retinal ganglion cells and amacrine cells was delayed. However, since the proportion of a given cell type within the transfected cell population at E18 was similar in knockdown and controls, the partial loss of some cell types was most-likely due to reduced RPC proliferation and not impaired cell differentiation. Photoreceptors displayed delayed migration at first, but had successfully reached the outer nuclear layer at E18. However, they increasingly differentiated into short wavelength-sensitive cones at the expense of medium/long wavelength-sensitive cones, while the proportion of rods was unaltered. Improperly formed sublaminae in the inner plexiform layer additionally suggested defects in synaptogenesis. Altogether, our data echoes effects of hypothyroidism and the loss of some other regulators of TH availability in the developing zebrafish and rodent retina. Therefore, the expression of MCT8 in RPCs is crucial for adequate TH uptake during cell type-specific events in retinal development.
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Affiliation(s)
- Pieter Vancamp
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Nele M A Bourgeois
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Anne M Houbrechts
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Veerle M Darras
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium.
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28
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Sharif NA. iDrugs and iDevices Discovery Research: Preclinical Assays, Techniques, and Animal Model Studies for Ocular Hypotensives and Neuroprotectants. J Ocul Pharmacol Ther 2018; 34:7-39. [PMID: 29323613 DOI: 10.1089/jop.2017.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Discovery ophthalmic research is centered around delineating the molecular and cellular basis of ocular diseases and finding and exploiting molecular and genetic pathways associated with them. From such studies it is possible to determine suitable intervention points to address the disease process and hopefully to discover therapeutics to treat them. An investigational new drug (IND) filing for a new small-molecule drug, peptide, antibody, genetic treatment, or a device with global health authorities requires a number of preclinical studies to provide necessary safety and efficacy data. Specific regulatory elements needed for such IND-enabling studies are beyond the scope of this article. However, to enhance the overall data packages for such entities and permit high-quality foundation-building publications for medical affairs, additional research and development studies are always desirable. This review aims to provide examples of some target localization/verification, ocular drug discovery processes, and mechanistic and portfolio-enhancing exploratory investigations for candidate drugs and devices for the treatment of ocular hypertension and glaucomatous optic neuropathy (neurodegeneration of retinal ganglion cells and their axons). Examples of compound screening assays, use of various technologies and techniques, deployment of animal models, and data obtained from such studies are also presented.
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Affiliation(s)
- Najam A Sharif
- 1 Global Alliances & External Research , Santen Incorporated, Emeryville, California.,2 Department of Pharmaceutical Sciences, Texas Southern University , Houston, Texas.,3 Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center , Fort Worth, Texas
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