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Zhong X, Li H, Tan S, Yang S, Zhu Z, Huang W, Cheng W, Wang W. Initial Retinal Nerve Fiber Layer Loss and Risk of Diabetic Retinopathy Over a Four-Year Period. Invest Ophthalmol Vis Sci 2024; 65:5. [PMID: 39365262 PMCID: PMC11457921 DOI: 10.1167/iovs.65.12.5] [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: 07/05/2024] [Accepted: 09/14/2024] [Indexed: 10/05/2024] Open
Abstract
Purpose The purpose of this study was to investigate whether the rapid rate of peripapillary retinal nerve fiber layer (pRNFL) thinning in short-term is associated with the future risk of developing diabetic retinopathy (DR). Methods This prospective cohort study utilized 4-year follow-up data from the Guangzhou Diabetic Eye Study. The pRNFL thickness was measured by optical coherence tomography (OCT). DR was graded by seven-field fundus photography after dilation of the pupil. Correlations between pRNFL thinning rate and DR were analyzed using logistic regression. The additive predictive value of the prediction model was assessed using the C-index, net reclassification index (NRI), and integrated discriminant improvement index (IDI). Results A total of 1012 patients with diabetes (1012 eyes) without DR at both baseline and 1-year follow-up were included in this study. Over the 4-year follow-up, 132 eyes (13%) developed DR. After adjusting for confounding factors, a faster rate of initial pRNFL thinning was significantly associated with the risk of DR (odds ratio per standard deviation [SD] decrease = 1.15, 95% confidence interval [CI] = 1.08 to 1.23, P < 0.001). Incorporating either the baseline pRNFL thickness or its thinning rate into conventional prediction models significantly improved the discriminatory power. Adding the rate of pRNFL thinning further enhanced the discriminative power compared with models with only baseline pRNFL thickness (C-index increased from 0.685 to 0.731, P = 0.040). The IDI and NRI were 0.114 and 0.463, respectively (P < 0.001). Conclusions The rate of initial pRNFL thinning was associated with DR occurrence and improved discriminatory power of traditional predictive models. This provides new insights into the management and screening of DR.
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Affiliation(s)
- Xiaoying Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Huangdong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
| | - Shaoying Tan
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Study Centre for SHARP Vision, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Study (CEVR), Hong Kong, China
| | - Shaopeng Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
| | - Ziyu Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
| | - Wenyong Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
| | - Weijing Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
| | - Wei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Study Center for Ocular Diseases, Sun Yat-Sen University, Guangzhou, China
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Hartnett ME, Fickweiler W, Adamis AP, Brownlee M, Das A, Duh EJ, Feener EP, King G, Kowluru R, Luhmann UF, Storti F, Wykoff CC, Aiello LP. Rationale of Basic and Cellular Mechanisms Considered in Updating the Staging System for Diabetic Retinal Disease. OPHTHALMOLOGY SCIENCE 2024; 4:100521. [PMID: 39006804 PMCID: PMC11245984 DOI: 10.1016/j.xops.2024.100521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 07/16/2024]
Abstract
Purpose Hyperglycemia is a major risk factor for early lesions of diabetic retinal disease (DRD). Updating the DRD staging system to incorporate relevant basic and cellular mechanisms pertinent to DRD is necessary to better address early disease, disease progression, the use of therapeutic interventions, and treatment effectiveness. Design We sought to review preclinical and clinical evidence on basic and cellular mechanisms potentially pertinent to DRD that might eventually be relevant to update the DRD staging system. Participants Not applicable. Methods The Basic and Cellular Mechanisms Working Group (BCM-WG) of the Mary Tyler Moore Vision Initiative carefully and extensively reviewed available preclinical and clinical evidence through multiple iterations and classified these. Main Outcome Measures Classification was made into evidence grids, level of supporting evidence, and anticipated future relevance to DRD. Results A total of 40 identified targets based on pathophysiology and other parameters for DRD were grouped into concepts or evaluated as specific candidates. VEGFA, peroxisome proliferator-activated receptor-alpha related pathways, plasma kallikrein, and angiopoietin 2 had strong agreement as promising for use as biomarkers in diagnostic, monitoring, predictive, prognostic, and pharmacodynamic responses as well as for susceptibility/risk biomarkers that could underlie new assessments and eventually be considered within an updated DRD staging system or treatment, based on the evidence and need for research that would fit within a 2-year timeline. The BCM-WG found there was strong reason also to pursue the following important concepts regarding scientific research of DRD acknowledging their regulation by hyperglycemia: inflammatory/cytokines, oxidative signaling, vasoprotection, neuroprotection, mitophagy, and nutrients/microbiome. Conclusion Promising targets that might eventually be considered within an updated DRD staging system or treatment were identified. Although the BCM-WG recognizes that at this stage little can be incorporated into a new DRD staging system, numerous potential targets and important concepts deserve continued support and research, as they may eventually serve as biomarkers and/or therapeutic targets with measurable benefits to patients with diabetes. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- M. Elizabeth Hartnett
- Department of Ophthalmology, Byers Eye Institute of Stanford University, Palo Alto, California
| | - Ward Fickweiler
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Anthony P. Adamis
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Michael Brownlee
- Departments of Medicine and Pathology, Einstein Diabetes Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Arup Das
- Department of Surgery, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Elia J. Duh
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Edward P. Feener
- Research Division, KalVista Pharmaceuticals, Inc, Cambridge, Massachusetts
| | - George King
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Renu Kowluru
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University, Detroit, Michigan
| | - Ulrich F.O. Luhmann
- Roche Pharmaceutical Research and Early Development, Translational Medicine Ophthalmology, Roche Innovation Center Basel, Basel, Switzerland
| | - Federica Storti
- Roche Pharmaceutical Research and Early Development, Translational Medicine Ophthalmology, Roche Innovation Center Basel, Basel, Switzerland
| | - Charles C. Wykoff
- Ophthalmology, Retina Consultants of Texas, Houston, Texas
- Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas
| | - Lloyd Paul Aiello
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
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Fang Y, Wang Q, Li Y, Zeng L, Liu J, Ou K. On implications of somatostatin in diabetic retinopathy. Neural Regen Res 2024; 19:1984-1990. [PMID: 38227526 DOI: 10.4103/1673-5374.390955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 10/10/2023] [Indexed: 01/17/2024] Open
Abstract
Somatostatin, a naturally produced neuroprotective peptide, depresses excitatory neurotransmission and exerts anti-proliferative and anti-inflammatory effects on the retina. In this review, we summarize the progress of somatostatin treatment of diabetic retinopathy through analysis of relevant studies published from February 2019 to February 2023 extracted from the PubMed and Google Scholar databases. Insufficient neuroprotection, which occurs as a consequence of declined expression or dysregulation of retinal somatostatin in the very early stages of diabetic retinopathy, triggers retinal neurovascular unit impairment and microvascular damage. Somatostatin replacement is a promising treatment for retinal neurodegeneration in diabetic retinopathy. Numerous pre-clinical and clinical trials of somatostatin analog treatment for early diabetic retinopathy have been initiated. In one such trial (EUROCONDOR), topical administration of somatostatin was found to exert neuroprotective effects in patients with pre-existing retinal neurodysfunction, but had no impact on the onset of diabetic retinopathy. Overall, we concluded that somatostatin restoration may be especially beneficial for the growing population of patients with early-stage retinopathy. In order to achieve early prevention of diabetic retinopathy initiation, and thereby salvage visual function before the appearance of moderate non-proliferative diabetic retinopathy, several issues need to be addressed. These include the needs to: a) update and standardize the retinal screening scheme to incorporate the detection of early neurodegeneration, b) identify patient subgroups who would benefit from somatostatin analog supplementation, c) elucidate the interactions of somatostatin, particularly exogenously-delivered somatostatin analogs, with other retinal peptides in the context of hyperglycemia, and d) design safe, feasible, low cost, and effective administration routes.
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Affiliation(s)
- Yanhong Fang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Qionghua Wang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Youjian Li
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
| | - Li Zeng
- Shandong Provincial Hospital, Shandong Laboratory Animal Center, Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong Province, China
| | - Jian Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kepeng Ou
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
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Simó R, Hernández C. Topical ocular administration of DPP-IV inhibitors: a new approach for treating diabetes-induced retinal neurodegeneration. Neural Regen Res 2024; 19:713-714. [PMID: 37843198 PMCID: PMC10664137 DOI: 10.4103/1673-5374.353492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/05/2022] [Accepted: 07/04/2023] [Indexed: 11/19/2022] Open
Affiliation(s)
- Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR); Department of Medicine, Autonomous University of Barcelona, Barcelona, Spain; Centro de Investigación Bioméica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR); Department of Medicine, Autonomous University of Barcelona, Barcelona, Spain; Centro de Investigación Bioméica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
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Xu X, Wang M, Zhang S, Wang J, Li X, Ma X, Luo Y, Sun X. Compound Danshen dripping pills prevent early diabetic retinopathy: roles of vascular protection and neuroprotection. Front Pharmacol 2024; 15:1294620. [PMID: 38318138 PMCID: PMC10839082 DOI: 10.3389/fphar.2024.1294620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
Introduction: Diabetic retinopathy (DR) represents a major cause of adult blindness, and early discovery has led to significant increase in the number of patients with DR. The drugs currently used for treatment, such as ranibizumab, mainly focus on the middle and late periods of DR, and thus do not meet the clinical need. Here, the potential mechanisms by which compound Danshen Dripping Pills (CDDP) might protect against early DR were investigated. Methods: Db/db mice were used to establish a DR model. The initial weights and HbA1c levels of the mice were monitored, and retinal pathology was assessed by hematoxylin-eosin (HE) staining. The vascular permeability of the retina and thickness of each retinal layer were measured, and electroretinogram were performed together with fundus fluorescein angiography and optical coherence tomography. The levels of inflammatory factors were examined in retinal tissue, as well as those of intercellular adhesion molecule 1 (ICAM-1), IL-6, and monocyte chemoattractant protein 1 (MCP-1) in the serum using ELISA. Immunohistochemistry was used to evaluate levels of vascular endothelial growth factor (VEGF), B-cell lymphoma 2 (Bcl-2), and Bclassociated X protein (Bax). Retinal cell injury and apoptosis were examined by TdT-mediated dUTP Nick End Labeling (TUNEL) assays. Results: The data showed that CDDP significantly improved cellular disarrangement. Imaging data indicated that CDDP could reduce vascular permeability and the amplitude of oscillatory potentials (OPs), and restore the thickness of the ganglion cell layer. Moreover, CDDP reduced the expression levels of inflammatory factors in both the retina and serum. Conclusion: These findings strongly suggest that CDDP prevents early DR through vascular and neuroprotection.
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Affiliation(s)
- Xiaoyu Xu
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Diabetes Research Center, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Mengchen Wang
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Diabetes Research Center, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Shuxia Zhang
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Diabetes Research Center, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Jing Wang
- State Key Laboratory of Core Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Group Co., Ltd., Tianjin, China
| | - Xinxin Li
- State Key Laboratory of Core Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Group Co., Ltd., Tianjin, China
| | - Xiaohui Ma
- State Key Laboratory of Core Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Group Co., Ltd., Tianjin, China
| | - Yun Luo
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Diabetes Research Center, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
| | - Xiaobo Sun
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Diabetes Research Center, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, Beijing, China
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Beijing, China
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Simó R, Hernández C. What else can we do to prevent diabetic retinopathy? Diabetologia 2023; 66:1614-1621. [PMID: 37277664 PMCID: PMC10390367 DOI: 10.1007/s00125-023-05940-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 03/31/2023] [Indexed: 06/07/2023]
Abstract
The classical modifiable factors associated with the onset and progression of diabetic retinopathy are the suboptimal control of blood glucose levels and hypertension, as well as dyslipidaemia. However, there are other less recognised modifiable factors that can play a relevant role, such as the presence of obesity or the abnormal distribution of adipose tissue, and others related to lifestyle such as the type of diet, vitamin intake, exercise, smoking and sunlight exposure. In this article we revisit the prevention of diabetic retinopathy based on modulating the modifiable risk factors, as well as commenting on the potential impact of glucose-lowering drugs on the condition. The emerging concept that neurodegeneration is an early event in the development of diabetic retinopathy points to neuroprotection as a potential therapeutic strategy to prevent the advanced stages of the disease. In this regard, the better phenotyping of very early stages of diabetic retinopathy and the opportunity of arresting its progression using treatments targeting the neurovascular unit (NVU) are discussed.
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Affiliation(s)
- Rafael Simó
- Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Vall d'Hebron Research Institute (VHIR), Vall d'Hebron University Hospital, Barcelona, Spain.
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM, ID CB15/00071), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.
| | - Cristina Hernández
- Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Vall d'Hebron Research Institute (VHIR), Vall d'Hebron University Hospital, Barcelona, Spain
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM, ID CB15/00071), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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Ramos H, Hernández C, Simó R, Simó-Servat O. Inflammation: The Link between Neural and Vascular Impairment in the Diabetic Retina and Therapeutic Implications. Int J Mol Sci 2023; 24:ijms24108796. [PMID: 37240138 DOI: 10.3390/ijms24108796] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/25/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
The etiology of diabetic retinopathy (DR) is complex, multifactorial and compromises all the elements of the retinal neurovascular unit (NVU). This diabetic complication has a chronic low-grade inflammatory component involving multiple inflammatory mediators and adhesion molecules. The diabetic milieu promotes reactive gliosis, pro-inflammatory cytokine production and leukocyte recruitment, which contribute to the disruption of the blood retinal barrier. The understanding and the continuous research of the mechanisms behind the strong inflammatory component of the disease allows the design of new therapeutic strategies to address this unmet medical need. In this context, the aim of this review article is to recapitulate the latest research on the role of inflammation in DR and to discuss the efficacy of currently administered anti-inflammatory treatments and those still under development.
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Affiliation(s)
- Hugo Ramos
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
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Hernández C, Simó-Servat O, Porta M, Grauslund J, Harding SP, Frydkjaer-Olsen U, García-Arumí J, Ribeiro L, Scanlon P, Cunha-Vaz J, Simó R. Serum glial fibrillary acidic protein and neurofilament light chain as biomarkers of retinal neurodysfunction in early diabetic retinopathy: results of the EUROCONDOR study. Acta Diabetol 2023; 60:837-844. [PMID: 36959506 DOI: 10.1007/s00592-023-02076-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/11/2023] [Indexed: 03/25/2023]
Abstract
AIMS Neurodegeneration and glial activation are primary events in the pathogenesis of diabetic retinopathy. Serum glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) are biomarkers of underlying neuroinflammatory and neurodegenerative disease processes. The aim of the present study was to assess the usefulness of these serum biomarkers for the identification and monitoring of retinal neurodysfunction in subjects with type 2 diabetes. METHODS A case-control study was designed including 38 patients from the placebo arm of the EUROCONDOR clinical trial: 19 with and 19 without retinal neurodysfunction assessed by multifocal electroretinography. GFAP and NfL were measured by Simoa. RESULTS Serum levels of GFAP and NfL directly correlated with age (r = 0.37, p = 0.023 and r = 0.54, p < 0.001, respectively). In addition, a direct correlation between GFAP and NfL was observed (r = 0.495, p = 0.002). Serum levels of GFAP were significantly higher at baseline in those subjects in whom neurodysfunction progressed after the 2 years of follow-up (139.1 ± 52.5 pg/mL vs. 100.2 ± 54.6 pg/mL; p = 0.04). CONCLUSIONS GFAP could be a useful serum biomarker for retinal neurodysfunction. Monitoring retinal neurodysfunction using blood samples would be of benefit in clinical decision-making. However, further research is needed to validate this result as well as to establish the best cutoff values.
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Affiliation(s)
- Cristina Hernández
- Diabetes and Metabolism Research Unit and CIBERDEM, Vall d'Hebron Research Institute, Vall d'Hebron Barcelona Hospital Campus, Passeig de La Vall d'Hebron, 119-129, 08035, Barcelona, Spain.
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit and CIBERDEM, Vall d'Hebron Research Institute, Vall d'Hebron Barcelona Hospital Campus, Passeig de La Vall d'Hebron, 119-129, 08035, Barcelona, Spain
| | - Massimo Porta
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Jakob Grauslund
- Research Unit of Ophthalmology, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Simon P Harding
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, and St. Paul's Eye Unit. Liverpool University Hospitals, Liverpool, UK
| | - Ulrik Frydkjaer-Olsen
- Research Unit of Ophthalmology, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - José García-Arumí
- Department of Ophthalmology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Luísa Ribeiro
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - Peter Scanlon
- Gloucestershire Hospitals National Health Service Foundation Trust, Cheltenham, UK
| | - José Cunha-Vaz
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - Rafael Simó
- Diabetes and Metabolism Research Unit and CIBERDEM, Vall d'Hebron Research Institute, Vall d'Hebron Barcelona Hospital Campus, Passeig de La Vall d'Hebron, 119-129, 08035, Barcelona, Spain
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9
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Kirthi V, Reed KI, Alattar K, Zuckerman BP, Bunce C, Nderitu P, Alam U, Clarke B, Hau S, Al-Shibani F, Petropoulos IN, Malik RA, Pissas T, Bergeles C, Vas P, Hopkins D, Jackson TL. Multimodal testing reveals subclinical neurovascular dysfunction in prediabetes, challenging the diagnostic threshold of diabetes. Diabet Med 2023; 40:e14952. [PMID: 36054221 PMCID: PMC10087038 DOI: 10.1111/dme.14952] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/28/2022]
Abstract
AIM To explore if novel non-invasive diagnostic technologies identify early small nerve fibre and retinal neurovascular pathology in prediabetes. METHODS Participants with normoglycaemia, prediabetes or type 2 diabetes underwent an exploratory cross-sectional analysis with optical coherence tomography angiography (OCT-A), handheld electroretinography (ERG), corneal confocal microscopy (CCM) and evaluation of electrochemical skin conductance (ESC). RESULTS Seventy-five participants with normoglycaemia (n = 20), prediabetes (n = 29) and type 2 diabetes (n = 26) were studied. Compared with normoglycaemia, mean peak ERG amplitudes of retinal responses at low (16-Td·s: 4.05 μV, 95% confidence interval [95% CI] 0.96-7.13) and high (32-Td·s: 5·20 μV, 95% CI 1.54-8.86) retinal illuminance were lower in prediabetes, as were OCT-A parafoveal vessel densities in superficial (0.051 pixels/mm2 , 95% CI 0.005-0.095) and deep (0.048 pixels/mm2 , 95% CI 0.003-0.093) retinal layers. There were no differences in CCM or ESC measurements between these two groups. Correlations between HbA1c and peak ERG amplitude at 32-Td·s (r = -0.256, p = 0.028), implicit time at 32-Td·s (r = 0.422, p < 0.001) and 16-Td·s (r = 0.327, p = 0.005), OCT parafoveal vessel density in the superficial (r = -0.238, p = 0.049) and deep (r = -0.3, p = 0.017) retinal layers, corneal nerve fibre length (CNFL) (r = -0.293, p = 0.017), and ESC-hands (r = -0.244, p = 0.035) were observed. HOMA-IR was a predictor of CNFD (β = -0.94, 95% CI -1.66 to -0.21, p = 0.012) and CNBD (β = -5.02, 95% CI -10.01 to -0.05, p = 0.048). CONCLUSIONS The glucose threshold for the diagnosis of diabetes is based on emergent retinopathy on fundus examination. We show that both abnormal retinal neurovascular structure (OCT-A) and function (ERG) may precede retinopathy in prediabetes, which require confirmation in larger, adequately powered studies.
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Affiliation(s)
- Varo Kirthi
- King's College London, London, UK
- King's College Hospital NHS Foundation Trust, London, UK
| | - Kate I Reed
- King's College Hospital NHS Foundation Trust, London, UK
| | | | | | - Catey Bunce
- Biomedical Research Centre, The Royal Marsden NHS Foundation Trust and the Institute of Cancer Research, London, UK
| | - Paul Nderitu
- King's College London, London, UK
- King's College Hospital NHS Foundation Trust, London, UK
| | - Uazman Alam
- University of Liverpool, Liverpool, UK
- Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
- Institute of Cardiovascular Sciences, Cardiac Centre, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
| | - Bronagh Clarke
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Scott Hau
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- University College London, London, UK
| | | | | | - Rayaz A Malik
- Institute of Cardiovascular Sciences, Cardiac Centre, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
- Division of Research, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Theodoros Pissas
- King's College London, London, UK
- University College London, London, UK
| | | | - Prashanth Vas
- King's College London, London, UK
- King's College Hospital NHS Foundation Trust, London, UK
| | - David Hopkins
- King's College London, London, UK
- King's College Hospital NHS Foundation Trust, London, UK
| | - Timothy L Jackson
- King's College London, London, UK
- King's College Hospital NHS Foundation Trust, London, UK
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10
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Invernizzi A, Chhablani J, Viola F, Gabrielle PH, Zarranz-Ventura J, Staurenghi G. Diabetic retinopathy in the pediatric population: Pathophysiology, screening, current and future treatments. Pharmacol Res 2023; 188:106670. [PMID: 36681366 DOI: 10.1016/j.phrs.2023.106670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023]
Abstract
Diabetic retinopathy (DR) is a sight threatening complication of diabetes mellitus (DM). The incidence of DR in the pediatric population has increased in the last two decades and it is expected to further rise in the future, following the increase in DM prevalence and obesity in youth. As early stages of the retinal disease are asymptomatic, screening programs are of extreme importance to guarantee a prompt diagnosis and avoid progression to more advanced, sight threatening stages. The management of DR comprises a wide range of actions starting from glycemic control, continuing with systemic and local medical treatments, up to para-surgical and surgical approaches to deal with the more aggressive complications. In this review we will describe the pathophysiology of DR trying to understand all the possible targets for currently available or future treatments. We will briefly consider the impact of screening techniques, screening strategies and their social and economic impact. Finally a large part of the review will be dedicated to medical and surgical treatments for DR including both currently available and under development therapies. Most of the available data in the literature on DR are focused on the adult population. The aim of our work is to provide clinicians and researchers with a comprehensive overview of the state of the art regarding DR in the pediatric population, considering the increasing numbers of this diseases in youth and the inevitable consequences that such a chronic disease could have if poorly managed in children.
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Affiliation(s)
- Alessandro Invernizzi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco", Luigi Sacco Hospital, University of Milan, Milan, Italy; The University of Sydney, Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, Sydney, New South Wales, Australia.
| | - Jay Chhablani
- UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Francesco Viola
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Pierre Henry Gabrielle
- Department of Ophthalmology, University Hospital, 14 rue Paul Gaffarel, 21079 Dijon, France
| | - Javier Zarranz-Ventura
- Institut Clínic of Ophthalmology (ICOF), Hospital Clínic, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco", Luigi Sacco Hospital, University of Milan, Milan, Italy
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11
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Maestroni S, Belvedere A, Viganò I, Meoni C, Di Matteo F, Gabellini D, Bandello F, Pierro L, Zerbini G. Diabetes has no additional impact on retinal ganglion cell loss in a mouse model of spontaneous glaucoma. Eur J Ophthalmol 2022; 33:1418-1424. [PMID: 36523153 PMCID: PMC10152559 DOI: 10.1177/11206721221145980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Purpose There is no valid medical treatment for diabetic retinopathy mostly because its pathogenesis remains largely unknown. Early stages of diabetic retinopathy, just like glaucoma, are characterized by the loss of retinal ganglion cells. Whether the two diseases may share a similar pathogenic background is unknown. Methods To clarify this issue the thickness of retinal nerve fiber layer was studied in vivo by optical coherence tomography in 10 Ins2Akita (diabetic) and 10 C57BL/6J (control) mice. The number of retinal ganglion cells and retina's surface covered by neurofilaments were quantified ex vivo in 12 normoglycemic DBA/2J (glaucoma) and 11 diabetic (alloxan-induced) DBA/2J mice (glaucoma + diabetes). Results At 16 weeks of age retinal nerve fiber layer was significantly thinner in Ins2Akita mice confirming the neurodegenerative impact of diabetes. Number of retinal ganglion cells and retina's surface covered by neurofilaments were similar in normoglycemic and diabetic DBA/2J mice with the exception of the superior quadrant where the number of retinal ganglion cells was increased in animals with glaucoma + diabetes. Conclusions In presence of glaucoma, diabetes is unable to induce further retinal ganglion cells loss. The hypothesis that the mechanism leading to retinal ganglion cells loss may be shared by the two diseases cannot be ruled out. Whether early diabetes-driven retinal neurodegeneration could be prevented by neuroprotective treatment proven to be effective in case of glaucoma, remains to be clarified.
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Affiliation(s)
- Silvia Maestroni
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Arianna Belvedere
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Ilaria Viganò
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Cesare Meoni
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Federico Di Matteo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy
| | - Daniela Gabellini
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy
| | - Luisa Pierro
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy
| | - Gianpaolo Zerbini
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
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12
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Ebrahimi M, Sivaprasad S, Thompson P, Perry G. Retinal Neurodegeneration in Euglycemic Hyperinsulinemia, Prediabetes, and Diabetes. Ophthalmic Res 2022; 66:385-397. [PMID: 36463857 DOI: 10.1159/000528503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2023]
Abstract
Diabetic retinopathy (DR) is a challenging public health problem mainly because of its growing prevalence and risk of blindness. In general, our current knowledge and practice have failed to prevent the onset or progression of DR to sight-threatening complications. While there are treatment options for sight-threatening complications of DR, it is crucial to pay more attention to the early stages of DR to decrease its prevalence. Growing evidence suggests many pathologic changes occur before clinical presentations of DR in euglycemic hyperinsulinemia, prediabetes, and diabetes. These pathological changes occur in retinal neurons, glia, and microvasculature. A new focus on these preclinical pathologies - especially on hyperinsulinemia - may provide further insight into disease mechanisms, endpoints for clinical trials, and druggable targets in early disease. Here, we review the current evidence on the pathophysiological changes reported in preclinical DR and appraise preventive and treatment options for DR.
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Affiliation(s)
- Moein Ebrahimi
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - George Perry
- Department of Biology, University of Texas and San Antonio, San Antonio, Texas, USA
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13
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Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications. Cells 2022; 11:cells11213362. [PMID: 36359761 PMCID: PMC9655436 DOI: 10.3390/cells11213362] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/24/2022] Open
Abstract
Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.
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14
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Bianco L, Arrigo A, Aragona E, Antropoli A, Berni A, Saladino A, Battaglia Parodi M, Bandello F. Neuroinflammation and neurodegeneration in diabetic retinopathy. Front Aging Neurosci 2022; 14:937999. [PMID: 36051309 PMCID: PMC9424735 DOI: 10.3389/fnagi.2022.937999] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/28/2022] [Indexed: 11/30/2022] Open
Abstract
Diabetic retinopathy (DR) is the most common complication of diabetes and has been historically regarded as a microangiopathic disease. Now, the paradigm is shifting toward a more comprehensive view of diabetic retinal disease (DRD) as a tissue-specific neurovascular complication, in which persistently high glycemia causes not only microvascular damage and ischemia but also intraretinal inflammation and neuronal degeneration. Despite the increasing knowledge on the pathogenic pathways involved in DR, currently approved treatments are focused only on its late-stage vasculopathic complications, and a single molecular target, vascular endothelial growth factor (VEGF), has been extensively studied, leading to drug development and approval. In this review, we discuss the state of the art of research on neuroinflammation and neurodegeneration in diabetes, with a focus on pathophysiological studies on human subjects, in vivo imaging biomarkers, and clinical trials on novel therapeutic options.
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Affiliation(s)
| | - Alessandro Arrigo
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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15
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New Insights into Treating Early and Advanced Stage Diabetic Retinopathy. Int J Mol Sci 2022; 23:ijms23158513. [PMID: 35955655 PMCID: PMC9368971 DOI: 10.3390/ijms23158513] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 11/17/2022] Open
Abstract
Diabetic retinopathy (DR) is the leading cause of preventable blindness in the working-age population. The disease progresses slowly, and we can roughly differentiate two stages: early-stage (ESDR), in which there are mild retinal lesions and visual acuity is generally preserved, and advanced-stage (ASDR), in which the structural lesions are significant and visual acuity is compromised. At present, there are no specific treatments for ESDR and the current recommended action is to optimize metabolic control and maintain close control of blood pressure. However, in the coming years, it is foreseeable that therapeutic strategies based in neuroprotection will be introduced in the clinical arena. This means that screening aimed at identifying patients in whom neuroprotective treatment might be beneficial will be crucial. Regarding the treatment of ASDR, the current primary course is based on laser photocoagulation and intravitreal injections of anti-angiogenic factors or corticosteroids. Repeated intravitreal injections of anti-VEGF agents as the first-line treatment would be replaced by more cost-effective and personalized treatments based on the results of “liquid biopsies” of aqueous humor. Finally, topical administration (i.e., eye drops) of neuroprotective, anti-inflammatory and anti-angiogenic agents will represent a revolution in the treatment of DR in the coming decade. In this article, all these approaches and others will be critically discussed from a holistic perspective.
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16
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Lechner J, Medina RJ, Lois N, Stitt AW. Advances in cell therapies using stem cells/progenitors as a novel approach for neurovascular repair of the diabetic retina. Stem Cell Res Ther 2022; 13:388. [PMID: 35907890 PMCID: PMC9338609 DOI: 10.1186/s13287-022-03073-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/20/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Diabetic retinopathy, a major complication of diabetes mellitus, is a leading cause of sigh-loss in working age adults. Progressive loss of integrity of the retinal neurovascular unit is a central element in the disease pathogenesis. Retinal ischemia and inflammatory processes drive interrelated pathologies such as blood retinal barrier disruption, fluid accumulation, gliosis, neuronal loss and/or aberrant neovascularisation. Current treatment options are somewhat limited to late-stages of the disease where there is already significant damage to the retinal architecture arising from degenerative, edematous and proliferative pathology. New preventive and interventional treatments to target early vasodegenerative and neurodegenerative stages of the disease are needed to ensure avoidance of sight-loss. MAIN BODY Historically, diabetic retinopathy has been considered a primarily microvascular disease of the retina and clinically it is classified based on the presence and severity of vascular lesions. It is now known that neurodegeneration plays a significant role during the pathogenesis. Loss of neurons has been documented at early stages in pre-clinical models as well as in individuals with diabetes and, in some, even prior to the onset of clinically overt diabetic retinopathy. Recent studies suggest that some patients have a primarily neurodegenerative phenotype. Retinal pigment epithelial cells and the choroid are also affected during the disease pathogenesis and these tissues may also need to be addressed by new regenerative treatments. Most stem cell research for diabetic retinopathy to date has focused on addressing vasculopathy. Pre-clinical and clinical studies aiming to restore damaged vasculature using vasoactive progenitors including mesenchymal stromal/stem cells, adipose stem cells, CD34+ cells, endothelial colony forming cells and induced pluripotent stem cell derived endothelial cells are discussed in this review. Stem cells that could replace dying neurons such as retinal progenitor cells, pluripotent stem cell derived photoreceptors and ganglion cells as well as Müller stem cells are also discussed. Finally, challenges of stem cell therapies relevant to diabetic retinopathy are considered. CONCLUSION Stem cell therapies hold great potential to replace dying cells during early and even late stages of diabetic retinopathy. However, due to the presence of different phenotypes, selecting the most suitable stem cell product for individual patients will be crucial for successful treatment.
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Affiliation(s)
- Judith Lechner
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK.
| | - Reinhold J Medina
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK
| | - Noemi Lois
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK.
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17
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Retinal Microvascular and Neuronal Changes Are Also Present, Even If Differently, in Adolescents with Type 1 Diabetes without Clinical Diabetic Retinopathy. J Clin Med 2022; 11:jcm11143982. [PMID: 35887746 PMCID: PMC9323684 DOI: 10.3390/jcm11143982] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 12/10/2022] Open
Abstract
The purpose of this study was to evaluate retinal changes in adolescents with childhood-onset, long-lasting type 1 diabetes mellitus (T1D). Patients and healthy controls (HC) underwent optical coherence tomography (OCT) and OCT-angiography (OCTA). Individual macular layers, peripapillary retinal nerve fiber layer (pRNFL), and vascular parameters (vessel area density (VAD), vessel length fraction (VLF) and vessel diameter index (VDI)) of macular superficial vascular (SVP), intermediate (ICP), deep (DCP) and radial peripapillary capillary plexuses (RPCP) were quantified. Thirty-nine patients (5 with (DR group) and 34 without (noDR group) diabetic retinopathy) and 20 HC were enrolled. The pRNFL and ganglion cell layer (GCL) were thicker in noDR compared to HC and DR, reaching statistically significant values versus HC for some sectors. At the macular level, VAD and VLF were reduced in DR versus HC in all plexuses, and versus noDR in SVP (p < 0.005 for all). At the RPCP level, VAD and VDI were increased in noDR versus HC, significantly for VDI (p = 0.0067). Glycemic indices correlated to retinal parameters. In conclusion, in T1D adolescents, retinal capillary and neuronal changes are present after long-lasting disease, even in the absence of clinical DR. These changes modify when clinical retinopathy develops. The precocious identification of specific OCT and OCTA changes may be a hallmark of subsequent overt retinopathy.
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18
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Takkar B, Sheemar A, Jayasudha R, Soni D, Narayanan R, Venkatesh P, Shivaji S, Das T. Unconventional avenues to decelerated diabetic retinopathy. Surv Ophthalmol 2022; 67:1574-1592. [PMID: 35803389 DOI: 10.1016/j.survophthal.2022.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
Diabetic retinopathy (DR) is an important microvascular complication of diabetes mellitus (DM), causing significant visual impairment worldwide. Current gold standards for retarding the progress of DR include blood sugar control and regular fundus screening. Despite these measures, the incidence and prevalence of DR and vision-threatening DR remain high. Given its slowly progressive course and long latent period, opportunities to contain or slow DR before it threatens vision must be explored. This narrative review assesses the recently described unconventional strategies to retard DR progression. These include gut-ocular flow, gene therapy, mitochondrial dysfunction-oxidative stress, stem cell therapeutics, neurodegeneration, anti-inflammatory treatments, lifestyle modification, and usage of phytochemicals. These therapies impact DR directly, while some of them also influence DM control. Most of these strategies are currently in the preclinical stage, and clinical evidence remains low. Nevertheless, our review suggests that these approaches have the potential for human use to prevent the progression of DR.
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Affiliation(s)
- Brijesh Takkar
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India; Indian Health Outcomes, Public Health, and Economics Research (IHOPE) Centre, L V Prasad Eye Institute, Hyderabad, India.
| | - Abhishek Sheemar
- Department of Ophthalmology, All India Institute of Medical Sciences, Jodhpur, India
| | | | - Deepak Soni
- Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, India
| | - Raja Narayanan
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India; Indian Health Outcomes, Public Health, and Economics Research (IHOPE) Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Pradeep Venkatesh
- Dr. RP Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Sisinthy Shivaji
- Prof. Brien Holden Eye Research Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Taraprasad Das
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, L V Prasad Eye Institute, Hyderabad, India
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19
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Cheung CMG, Fawzi A, Teo KY, Fukuyama H, Sen S, Tsai WS, Sivaprasad S. Diabetic macular ischaemia- a new therapeutic target? Prog Retin Eye Res 2022; 89:101033. [PMID: 34902545 PMCID: PMC11268431 DOI: 10.1016/j.preteyeres.2021.101033] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/25/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022]
Abstract
Diabetic macular ischaemia (DMI) is traditionally defined and graded based on the angiographic evidence of an enlarged and irregular foveal avascular zone. However, these anatomical changes are not surrogate markers for visual impairment. We postulate that there are vascular phenotypes of DMI based on the relative perfusion deficits of various retinal capillary plexuses and choriocapillaris. This review highlights several mechanistic pathways, including the role of hypoxia and the complex relation between neurons, glia, and microvasculature. The current animal models are reviewed, with shortcomings noted. Therefore, utilising the advancing technology of optical coherence tomography angiography (OCTA) to identify the reversible DMI phenotypes may be the key to successful therapeutic interventions for DMI. However, there is a need to standardise the nomenclature of OCTA perfusion status. Visual acuity is not an ideal endpoint for DMI clinical trials. New trial endpoints that represent disease progression need to be developed before irreversible vision loss in patients with DMI. Natural history studies are required to determine the course of each vascular and neuronal parameter to define the DMI phenotypes. These DMI phenotypes may also partly explain the development and recurrence of diabetic macular oedema. It is also currently unclear where and how DMI fits into the diabetic retinopathy severity scales, further highlighting the need to better define the progression of diabetic retinopathy and DMI based on both multimodal imaging and visual function. Finally, we discuss a complete set of proposed therapeutic pathways for DMI, including cell-based therapies that may provide restorative potential.
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Affiliation(s)
- Chui Ming Gemmy Cheung
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore; Duke-NUS Medical School, National University of Singapore, Singapore
| | | | - Kelvin Yc Teo
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore
| | | | | | - Wei-Shan Tsai
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom.
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20
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Fedotkina O, Jain R, Prasad RB, Luk A, García-Ramírez M, Özgümüs T, Cherviakova L, Khalimon N, Svietleisha T, Buldenko T, Kravchenko V, Jain D, Vaag A, Chan J, Khalangot MD, Hernández C, Nilsson PM, Simo R, Artner I, Lyssenko V. Neuronal Dysfunction Is Linked to the Famine-Associated Risk of Proliferative Retinopathy in Patients With Type 2 Diabetes. Front Neurosci 2022; 16:858049. [PMID: 35600617 PMCID: PMC9119187 DOI: 10.3389/fnins.2022.858049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Persons with type 2 diabetes born in the regions of famine exposures have disproportionally elevated risk of vision-threatening proliferative diabetic retinopathy (PDR) in adulthood. However, the underlying mechanisms are not known. In the present study, we aimed to investigate the plausible molecular factors underlying progression to PDR. To study the association of genetic variants with PDR under the intrauterine famine exposure, we analyzed single nucleotide polymorphisms (SNPs) that were previously reported to be associated with type 2 diabetes, glucose, and pharmacogenetics. Analyses were performed in the population from northern Ukraine with a history of exposure to the Great Ukrainian Holodomor famine [the Diagnostic Optimization and Treatment of Diabetes and its Complications in the Chernihiv Region (DOLCE study), n = 3,583]. A validation of the top genetic findings was performed in the Hong Kong diabetes registry (HKDR, n = 730) with a history of famine as a consequence of the Japanese invasion during WWII. In DOLCE, the genetic risk for PDR was elevated for the variants in ADRA2A, PCSK9, and CYP2C19*2 loci, but reduced at PROX1 locus. The association of ADRA2A loci with the risk of advanced diabetic retinopathy in famine-exposed group was further replicated in HKDR. The exposure of embryonic retinal cells to starvation for glucose, mimicking the perinatal exposure to famine, resulted in sustained increased expression of Adra2a and Pcsk9, but decreased Prox1. The exposure to starvation exhibited a lasting inhibitory effects on neurite outgrowth, as determined by neurite length. In conclusion, a consistent genetic findings on the famine-linked risk of ADRA2A with PDR indicate that the nerves may likely to be responsible for communicating the effects of perinatal exposure to famine on the elevated risk of advanced stages of diabetic retinopathy in adults. These results suggest the possibility of utilizing neuroprotective drugs for the prevention and treatment of PDR.
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Affiliation(s)
- Olena Fedotkina
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Ruchi Jain
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
| | - Rashmi B. Prasad
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
| | - Andrea Luk
- Prince of Wales Hospital, Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | | | - Türküler Özgümüs
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway
| | | | | | | | - Tetiana Buldenko
- Department of Health Care of Chernihiv Regional State Administration, Chernihiv, Ukraine
| | - Victor Kravchenko
- Komisarenko Institute of Endocrinology and Metabolism, Kyiv, Ukraine
| | - Deepak Jain
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
| | - Allan Vaag
- Steno Diabetes Center Copenhagen, Copenhagen, Denmark
| | - Juliana Chan
- Prince of Wales Hospital, Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Mykola D. Khalangot
- Komisarenko Institute of Endocrinology and Metabolism, Kyiv, Ukraine
- Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | | | - Peter M. Nilsson
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
| | - Rafael Simo
- Vall d’Hebron Research Institute and CIBERDEM, Barcelona, Spain
| | - Isabella Artner
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
| | - Valeriya Lyssenko
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway
- Department of Clinical Sciences, Lund University Diabetes Center, Skane University Hospital, Malmö, Sweden
- *Correspondence: Valeriya Lyssenko,
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21
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Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
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22
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Simó R, Simó-Servat O, Bogdanov P, Hernández C. Diabetic Retinopathy: Role of Neurodegeneration and Therapeutic Perspectives. Asia Pac J Ophthalmol (Phila) 2022; 11:160-167. [PMID: 35533335 DOI: 10.1097/apo.0000000000000510] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
ABSTRACT Retinal neurodegeneration plays a significant role in the pathogenesis of diabetic retinopathy, the leading cause of preventable blindness. The hallmarks of diabetes-induced neurodegeneration are neural cell apoptosis and glial activation, which seem even before vascular lesions can be detected by ophthalmoscopic examination. The molecular mediators of retinal neurodegeneration include proinflamma- tory cytokines, oxidative stress, mitochondrial dysfunction, and the molecular pathways closely related to chronic hyperglycemia. In this article, an overview of the main components of neurodegeneration, its key underlying mechanisms, and the more useful experimental models for investigative purposes will be given. In addition, the results of most relevant treatments based on neuroprotection, and the research gaps that should be filled will be critically reviewed.
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Affiliation(s)
- Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
| | - Patricia Bogdanov
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), Madrid, Spain
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23
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Thagaard MS, Vergmann AS, Grauslund J. Topical treatment of diabetic retinopathy: a systematic review. Acta Ophthalmol 2022; 100:136-147. [PMID: 34096180 DOI: 10.1111/aos.14912] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 03/16/2021] [Accepted: 05/01/2021] [Indexed: 12/20/2022]
Abstract
Diabetic retinopathy (DR) is the most common microvascular complication in diabetes and may cause severe visual impairment. Until late stages of DR, treatment options are limited. The aim of the present review was to investigate whether changes of DR might be influenced by topical treatment with eye drops. This systematic review included both randomized and non-randomized human clinical studies on the subject. A systematic search of PubMed Medline, Embase and Scopus databases yielded 710 studies. No inclusion criteria regarding classification of DR were defined. Reference lists as well as first authors were screened for the inclusion of additional studies. Potential bias of the randomized studies was assessed using the Cochrane Risk of Bias tool. Nineteen studies suitable for inclusion were identified. Seven studies were randomized trials. These examined 11 different pharmacological groups of drugs in DR. A favourable effect of corticosteroid eye drops in diabetic macular oedema (DMO) was reported in four studies, and another study reported a positive trend. Eye drops with non-steroidal anti-inflammatory drugs were also reported to have a favourable effect in DMO, but not in non-center involving DMO. Application of neuroprotective agents was found effective in patients with pre-existing neurodegeneration in three studies. The remaining studies of DMO and DR were heterogeneous in both designs and results. Studies on treatment of DR with topical eye drops vary with regards to patient population, interventional drugs, study design, and outcome measures. Treatment of DR with eye drops was found effective in the aforementioned cases, but there is still a need for further investigations of long-term, randomized controlled trials in any of the reported pharmacological group.
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Affiliation(s)
- Mikkel S. Thagaard
- Department of Ophthalmology Odense University Hospital Odense Denmark
- Department of Ophthalmology Hospital Sønderjylland Sønderborg Denmark
| | - Anna S. Vergmann
- Research Unit of Ophthalmology Department of Clinical Research Faculty of Health Sciences University of Southern Denmark Odense Denmark
| | - Jakob Grauslund
- Department of Ophthalmology Odense University Hospital Odense Denmark
- Research Unit of Ophthalmology Department of Clinical Research Faculty of Health Sciences University of Southern Denmark Odense Denmark
- Steno Diabetes Center Odense Odense Denmark
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24
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Understanding Neurodegeneration from a Clinical and Therapeutic Perspective in Early Diabetic Retinopathy. Nutrients 2022; 14:nu14040792. [PMID: 35215442 PMCID: PMC8877033 DOI: 10.3390/nu14040792] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 02/05/2023] Open
Abstract
Recent evidence indicates that neurodegeneration is a critical element of diabetic retinopathy (DR) pathogenesis. The neuronal cells’ apoptosis contributes to microvascular impairment and blood–retinal barrier breakdown. Therefore, neurodegeneration represents an early intervention target to slow and prevent the development of microvascular alterations visible on clinical examination. Multimodal imaging features and functional assessment can permit the identification of neuronal damage in a subclinical stage before the recognition of DR signs. Clinical features of neurodegeneration are crucial in identifying patients at high risk of developing a vascular impairment and, thus, serve as outcome measures to understand the efficacy of supplementation. The optimal approach for targeting neurodegeneration contemplates the use of topical compounds that possibly act on different elements of the pathogenic cascade. To date, clinical trials available on humans tested three different topical agents, including brimonidine, somatostatin, and citicoline, with promising results.
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25
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It is time for a moonshot to find “Cures” for diabetic retinal disease. Prog Retin Eye Res 2022; 90:101051. [DOI: 10.1016/j.preteyeres.2022.101051] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/19/2022] [Accepted: 01/31/2022] [Indexed: 12/13/2022]
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26
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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: 30] [Impact Index Per Article: 15.0] [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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27
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Neurovascular Impairment and Therapeutic Strategies in Diabetic Retinopathy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:ijerph19010439. [PMID: 35010703 PMCID: PMC8744686 DOI: 10.3390/ijerph19010439] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/25/2021] [Accepted: 12/30/2021] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy has recently been defined as a highly specific neurovascular complication of diabetes. The chronic progression of the impairment of the interdependence of neurovascular units (NVUs) is associated with the pathogenesis of diabetic retinopathy. The NVUs consist of neurons, glial cells, and vascular cells, and the interdependent relationships between these cells are disturbed under diabetic conditions. Clinicians should understand and update the current knowledge of the neurovascular impairments in diabetic retinopathy. Above all, neuronal cell death is an irreversible change, and it is directly related to vision loss in patients with diabetic retinopathy. Thus, neuroprotective and vasoprotective therapies for diabetic retinopathy must be established. Understanding the physiological and pathological interdependence of the NVUs is helpful in establishing neuroprotective and vasoprotective therapies for diabetic retinopathy. This review focuses on the pathogenesis of the neurovascular impairments and introduces possible neurovascular protective therapies for diabetic retinopathy.
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28
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Arendt Nielsen T, Sega R, Uggerhøj Andersen C, Vorum H, Mohr Drewes A, Jakobsen PE, Brock B, Brock C. Liraglutide Treatment Does Not Induce Changes in the Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Diabetic Retinopathy. J Ocul Pharmacol Ther 2021; 38:114-121. [PMID: 34918951 DOI: 10.1089/jop.2021.0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Purpose: Liraglutide treatment has shown promising anti-inflammatory and nerve regenerative results in preclinical and clinical trials. We sought to assess if liraglutide treatment would induce nerve regeneration through its anti-inflammatory and neurotrophic mechanisms by increasing peripapillary retinal nerve fiber layer (RNFL) thickness in individuals with long-term type 1 diabetes. Methods: Secondary analyses were performed on a prospective, double-blinded, randomized, placebo-controlled trial on adults with type 1 diabetes, distal symmetric polyneuropathy (DSPN), and confirmed diabetic retinopathy, who were randomized 1:1 to either 26 weeks placebo or liraglutide treatment. The primary endpoint was a change in peripapillary RNFL thickness between treatments, assessed by optical coherence tomography. Results: Thirty-seven participants were included in the secondary analysis. No differences in mean peripapillary RNFL thickness (overall ΔMean RNFL thickness; liraglutide -1 (±8) μm (-1%) vs. placebo -1 (±5) μm (-1%), P = 0.78, n = 37) or any of the quadrants. Peripapillary RNFL thicknesses were shown between treatments in either nonproliferative (ΔMean RNFL thickness; liraglutide -1 (±5) μm (-1%) vs. placebo 0 (±4) μm (0%), P = 0.80, N = 26) or proliferative diabetic retinopathy subgroup (ΔMean RNFL thickness; liraglutide -2 (±14) μm (-3%) vs. placebo -1 (±6) μm (-2%), P = 0.88, N = 11). Conclusions: In this study, 26 weeks of liraglutide treatment did not induce measurable changes in the assessed optic nerve thickness. Thus, this methodology does not support the induction of substantial nerve regeneration in this cohort with established retinopathy and DSPN. The trial was approved by the Danish Health and Medicines Authority. Informed consent was obtained from all participants. TODINELI study: EUDRA CT: 2013-004375-12, Ethics Ref: N-20130077 Clinical trial registration number: clinicaltrials.gov NCT02138045.
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Affiliation(s)
- Thomas Arendt Nielsen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Department of Ophthalmology, Aalborg University Hospital, Aalborg University, Aalborg, Denmark
| | - Rok Sega
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital & Clinical Institute, Aalborg University, Aalborg, Denmark
| | - Carl Uggerhøj Andersen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Department of Ophthalmology, Aalborg University Hospital, Aalborg University, Aalborg, Denmark
| | - Henrik Vorum
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Department of Ophthalmology, Aalborg University Hospital, Aalborg University, Aalborg, Denmark
| | - Asbjørn Mohr Drewes
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital & Clinical Institute, Aalborg University, Aalborg, Denmark.,Steno Diabetes Center North, Aalborg, Denmark
| | - Poul Erik Jakobsen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Steno Diabetes Center North, Aalborg, Denmark.,Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark
| | - Birgitte Brock
- Steno Diabetes Center Copenhagen, Gentofte, Denmark.,Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Christina Brock
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital & Clinical Institute, Aalborg University, Aalborg, Denmark.,Steno Diabetes Center North, Aalborg, Denmark
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29
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Abstract
PURPOSE OF REVIEW Diabetic retinopathy (DR), the leading cause of blindness in working-aged adults, remains clinically defined and staged by its vascular manifestations. However, early retinal neurodegeneration may precede vascular pathology, suggesting that this neuronal damage may contribute to disease pathogenesis and represent an independent target for intervention. This review will discuss the evidence and implications for diabetic retinal neurodegeneration. RECENT FINDINGS A growing body of literature has identified progressive retinal thinning and visual dysfunction in patients with diabetes even prior to the onset of DR, though advances in retinal vascular imaging suggest that vascular remodeling and choroidal changes occur during these early stages as well. Animal models of diabetes and in vitro studies have also suggested that diabetes may directly affect the retinal neural and glial tissue, providing support to the concept that diabetic retinal neurodegeneration occurs early in the disease and suggesting potentially relevant molecular pathways. Diabetic retinal neurodegeneration may represent a "preclinical" manifestation of diabetic retinal disease and remains an active area of investigation. As the natural history and molecular mechanisms become increasingly understood, it may lead to upcoming developments in not only the treatment options but also the clinical definition of DR.
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Affiliation(s)
- Mira M Sachdeva
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Maumenee 748, Baltimore, MD, 21287 MD, USA.
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30
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Bontzos G, Kabanarou SA, Gkizis I, Ragkousis A, Xirou T, Peto T. Retinal neurodegeneration, macular circulation and morphology of the foveal avascular zone in diabetic patients: quantitative cross-sectional study using OCT-A. Acta Ophthalmol 2021; 99:e1135-e1140. [PMID: 33423370 DOI: 10.1111/aos.14754] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE Using OCT-A to investigate the association between neurodegeneration and vascular morphology in diabetic retinopathy (DR). METHODS Cross-sectional study. One hundred and sixty-two patients were enrolled and following fundoscopy were assigned to two groups according to DR severity: 54 patients to the group of no clinical signs of DR (noDR) and 54 to the non-proliferative DR (NPDR) group. Fifty-four age-matched patients without known diabetes were recruited as the control group. Patients underwent full ophthalmic examination followed by OCT-A. Central retinal thickness (CRT), vessel density (VD) in the superficial and deep retinal layers and foveal avascular zone (FAZ) area were measured. Additionally, ganglion cell complex (GCC) layer thickness along with global loss volume (GLV) and focal loss volume (FLV) indices was measured. RESULTS In total, 85 men with mean age of 51.93 ± 9.03 and 77 women with age of 50.14 ± 10.35 were examined. Mean diabetes duration was 4.62 ± 2.16 years in the noDR group and 11.34 ± 2.73 years in the NPDR group (p < 0.001). Superficial VD (sVD) and deep VD (dVD) were significantly different only between noDR and NPDR groups (p < 0.001 for both comparisons), but no statistically significant difference was observed between the controls and the DR groups. Global loss volume was significantly higher in the NPDR (4.38 ± 2.22) compared to the noDR group (3.24 ± 1.76; p < 0.03). Focal loss volume was significantly higher in both noDR (1.22 ± 1.03) and NPDR (2.09 ± 1.72) groups compared to controls (0.95 ± 0.83; p < 0.001 between noDR and NPDR and p = 0.02 between control and noDR groups). Significant associations were found between GLV and deep VD (p < 0.01, r = -0.48), FLV and superficial VD (p < 0.01, r = -0.42) and FLV with deep VD (p < 0.01, r = -0.64). CONCLUSION In this study, we evaluated the impact of DR in both the vascular layers and neural components of the retina as expressed by FAZ, sVD, dVD and GCC thickness, FLV and GLV using OCT-A. We found that FLV was significantly higher in both noDR and NPDR groups indicating that in progressive DR stages FLV values might be increased, which might serve as an early index of neuronal damage in patients with diabetes even in the absence of overt DR signs.
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Affiliation(s)
- Georgios Bontzos
- Department of Ophthalmology Korgialenio‐Benakio Hellenic Red Cross Hospital Athens Greece
| | - Stamatina A. Kabanarou
- Department of Ophthalmology Korgialenio‐Benakio Hellenic Red Cross Hospital Athens Greece
| | - Ilias Gkizis
- Department of Ophthalmology Korgialenio‐Benakio Hellenic Red Cross Hospital Athens Greece
| | - Antonios Ragkousis
- Department of Ophthalmology Korgialenio‐Benakio Hellenic Red Cross Hospital Athens Greece
| | - Tina Xirou
- Department of Ophthalmology Korgialenio‐Benakio Hellenic Red Cross Hospital Athens Greece
| | - Tunde Peto
- Department of Ophthalmology Centre for Public Health Institute of Clinical Sciences School of Medicine Queen's University Belfast Belfast UK
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31
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Channa R, Lee K, Staggers KA, Mehta N, Zafar S, Gao J, Frankfort BJ, Chua SYL, Khawaja AP, Foster PJ, Patel PJ, Minard CG, Amos C, Abramoff MD. Detecting retinal neurodegeneration in people with diabetes: Findings from the UK Biobank. PLoS One 2021; 16:e0257836. [PMID: 34587216 PMCID: PMC8480885 DOI: 10.1371/journal.pone.0257836] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 09/11/2021] [Indexed: 01/23/2023] Open
Abstract
Importance Efforts are underway to incorporate retinal neurodegeneration in the diabetic retinopathy severity scale. However, there is no established measure to quantify diabetic retinal neurodegeneration (DRN). Objective We compared total retinal, macular retinal nerve fiber layer (mRNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness among participants with and without diabetes (DM) in a population-based cohort. Design/setting/participants Cross-sectional analysis, using the UK Biobank data resource. Separate general linear mixed models (GLMM) were created using DM and glycated hemoglobin as predictor variables for retinal thickness. Sub-analyses included comparing thickness measurements for patients with no/mild diabetic retinopathy (DR) and evaluating factors associated with retinal thickness in participants with and without diabetes. Factors found to be significantly associated with DM or thickness were included in a multiple GLMM. Exposure Diagnosis of DM was determined via self-report of diagnosis, medication use, DM-related complications or glycated hemoglobin level of ≥ 6.5%. Main outcomes and measures Total retinal, mRNFL and GC-IPL thickness. Results 74,422 participants (69,985 with no DM; 4,437 with DM) were included. Median age was 59 years, 46% were men and 92% were white. Participants with DM had lower total retinal thickness (-4.57 μm, 95% CI: -5.00, -4.14; p<0.001), GC-IPL thickness (-1.73 μm, 95% CI: -1.86, -1.59; p<0.001) and mRNFL thickness (-0.68 μm, 95% CI: -0.81, -0.54; p<0.001) compared to those without DM. After adjusting for co-variates, in the GLMM, total retinal thickness was 1.99 um lower (95% CI: -2.47, -1.50; p<0.001) and GC-IPL was 1.02 μm lower (95% CI: -1.18, -0.87; p<0.001) among those with DM compared to without. mRNFL was no longer significantly different (p = 0.369). GC-IPL remained significantly lower, after adjusting for co-variates, among those with DM compared to those without DM when including only participants with no/mild DR (-0.80 μm, 95% CI: -0.98, -0.62; p<0.001). Total retinal thickness decreased 0.40 μm (95% CI: -0.61, -0.20; p<0.001), mRNFL thickness increased 0.20 μm (95% CI: 0.14, 0.27; p<0.001) and GC-IPL decreased 0.26 μm (95% CI: -0.33, -0.20; p<0.001) per unit increase in A1c after adjusting for co-variates. Among participants with diabetes, age, DR grade, ethnicity, body mass index, glaucoma, spherical equivalent, and visual acuity were significantly associated with GC-IPL thickness. Conclusion GC-IPL was thinner among participants with DM, compared to without DM. This difference persisted after adjusting for confounding variables and when considering only those with no/mild DR. This confirms that GC-IPL thinning occurs early in DM and can serve as a useful marker of DRN.
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Affiliation(s)
- Roomasa Channa
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, United States of America
- * E-mail:
| | - Kyungmoo Lee
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States of America
| | - Kristen A. Staggers
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, United States of America
| | - Nitish Mehta
- New York University, New York, NY, United States of America
| | - Sidra Zafar
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, United States of America
| | - Jie Gao
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States of America
| | - Benjamin J. Frankfort
- Department of Ophthalmology and Neurosciences, Baylor College of Medicine, Houston, TX, United States of America
| | - Sharon Y. L. Chua
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, United Kingdom
| | - Anthony P. Khawaja
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, United Kingdom
| | - Paul J. Foster
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, United Kingdom
| | - Praveen J. Patel
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, United Kingdom
| | - Charles G. Minard
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, United States of America
| | - Chris Amos
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, United States of America
| | - Michael D. Abramoff
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States of America
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32
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Oshitari T. Diabetic retinopathy: neurovascular disease requiring neuroprotective and regenerative therapies. Neural Regen Res 2021; 17:795-796. [PMID: 34472475 PMCID: PMC8530146 DOI: 10.4103/1673-5374.322457] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Inohana, Chuo-ku; Department of Ophthalmology, International University of Health and Welfare School of Medicine, Kozunomori, Narita, Chiba, Japan
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33
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Tamhane M, Luu KT, Attar M. Ocular Pharmacokinetics of Brimonidine Drug Delivery System in Monkeys and Translational Modeling for Selection of Dose and Frequency in Clinical Trials. J Pharmacol Exp Ther 2021; 378:207-214. [PMID: 34210753 DOI: 10.1124/jpet.120.000483] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/28/2021] [Indexed: 01/07/2023] Open
Abstract
Brimonidine, a selective α 2-adrenoceptor agonist, displays putative retinal cyto- and neuroprotective activity in vitro and in vivo. An intravitreal sustained-release brimonidine implant, Brimonidine Posterior Segment Drug Delivery System (brimonidine DDS), allowing targeted drug delivery to the retina has been developed for potential clinical application. This study evaluates the in vivo posterior segment pharmacokinetics of brimonidine DDS implant in the monkey eye and applies translational pharmacokinetic modeling to predict tissue exposure in the human eye. Anesthetized cynomolgus monkeys received a single intravitreal injection of brimonidine DDS 400 µg implant before removal of study eyes at days 7, 30, 60, 92, 120, and 150 postimplant (three to four animals per time point) for assay of brimonidine in aqueous humor, vitreous, and retina samples. Brimonidine concentrations in the human eye were modeled using a linear, three-compartment model assuming bidirectional distribution to/from the aqueous humor and retina and elimination from the aqueous humor. Monkey tissue volumes were scaled up to human values; intercompartmental and elimination rate constants were assumed to be identical in the two species. Modeling and simulations were performed using NONMEM v. 7.3, R 3.5.1. Brimonidine exposure was highest in the monkey vitreous and retina; concentrations in the central (macula) and peripheral retina were maintained at high levels (>100 ng/g) for 3 to 4 months. Simulated brimonidine concentration-time profiles in human macula indicated that brimonidine DDS 400 µg implant would deliver effective drug concentrations (20.7‒82.2 ng/g, based on animal pharmacology) for approximately 3 months. Accordingly, administration of the 400 µg implant at 3-month intervals is recommended. SIGNIFICANCE STATEMENT: Brimonidine, an α 2-adrenoceptor agonist, is cyto- and neuroprotective in animal models of retinal/optic nerve injury. Brimonidine Posterior Segment Drug Delivery System (brimonidine DDS) is an intravitreal sustained-release implant with potential ophthalmological applications. This study explores the pharmacokinetics of brimonidine DDS 400 µg implant in the monkey eye and uses compartmental modeling to predict human ocular tissue exposure. Targeted retinal brimonidine delivery from vitreous was demonstrated in monkeys. Simulated tissue concentration-time profiles indicated persistence of pharmacologically effective brimonidine concentrations for ≈3 months in human retina.
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Simó R, Simó-Servat O, Bogdanov P, Hernández C. Neurovascular Unit: A New Target for Treating Early Stages of Diabetic Retinopathy. Pharmaceutics 2021; 13:pharmaceutics13081320. [PMID: 34452281 PMCID: PMC8399715 DOI: 10.3390/pharmaceutics13081320] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 01/02/2023] Open
Abstract
The concept of diabetic retinopathy as a microvascular disease has evolved and is now considered a more complex diabetic complication in which neurovascular unit impairment plays an essential role and, therefore, can be considered as a main therapeutic target in the early stages of the disease. However, neurodegeneration is not always the apparent primary event in the natural story of diabetic retinopathy, and a phenotyping characterization is recommendable to identify those patients in whom neuroprotective treatment might be of benefit. In recent years, a myriad of treatments based on neuroprotection have been tested in experimental models, but more interestingly, there are drugs with a dual activity (neuroprotective and vasculotropic). In this review, the recent evidence concerning the therapeutic approaches targeting neurovascular unit impairment will be presented, along with a critical review of the scientific gaps and problems which remain to be overcome before our knowledge can be transferred to clinical practice.
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Affiliation(s)
- Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
- Correspondence:
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Patricia Bogdanov
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain; (O.S.-S.); (P.B.); (C.H.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain
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The Pathogenesis and Therapeutic Approaches of Diabetic Neuropathy in the Retina. Int J Mol Sci 2021; 22:ijms22169050. [PMID: 34445756 PMCID: PMC8396448 DOI: 10.3390/ijms22169050] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/19/2021] [Accepted: 08/19/2021] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy is a major retinal disease and a leading cause of blindness in the world. Diabetic retinopathy is a neurovascular disease that is associated with disturbances of the interdependent relationship of cells composed of the neurovascular units, i.e., neurons, glial cells, and vascular cells. An impairment of these neurovascular units causes both neuronal and vascular abnormalities in diabetic retinopathy. More specifically, neuronal abnormalities including neuronal cell death and axon degeneration are irreversible changes that are directly related to the vision reduction in diabetic patients. Thus, establishment of neuroprotective and regenerative therapies for diabetic neuropathy in the retina is an emergent task for preventing the blindness of patients with diabetic retinopathy. This review focuses on the pathogenesis of the neuronal abnormalities in diabetic retina including glial abnormalities, neuronal cell death, and axon degeneration. The possible molecular cell death pathways and intrinsic survival and regenerative pathways are also described. In addition, therapeutic approaches for diabetic neuropathy in the retina both in vitro and in vivo are presented. This review should be helpful for providing clues to overcome the barriers for establishing neuroprotection and regeneration of diabetic neuropathy in the retina.
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Effects of the Topical Administration of Semaglutide on Retinal Neuroinflammation and Vascular Leakage in Experimental Diabetes. Biomedicines 2021; 9:biomedicines9080926. [PMID: 34440130 PMCID: PMC8392846 DOI: 10.3390/biomedicines9080926] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND An unexpected increase in the rate of severe diabetic retinopathy was observed in the Semaglutide in Subjects with Type 2 Diabetes (SUSTAIN)-6 clinical trial. Although this effect was attributed to a rapid decrease in blood glucose levels, a direct deleterious effect of semaglutide on the retina could not be ruled out. In order to shed light on this issue, we have performed a study aimed at testing the direct effect of semaglutide administered by eye drops on retinal neuroinflammation and microvascular abnormalities using the db/db mouse model. METHODS Eye drops containing semaglutide (0.33 mg/mL; 5 μL once/daily) or vehicle (PBS; 5 μL once daily) were administered for 15 days. RESULTS We found that semaglutide significantly reduced glial activation, as well as the retinal expression of Nuclear factor kB (NF-κB), proinflammatory cytokines (IL-1β, IL-6, IL-18) and Intercellular Adhesion Molecule (ICAM)-1. In addition, semaglutide prevented the apoptosis of cells from the retinal ganglion layer and activated the protein kinase B (AKT) pathway. Finally, a dramatic decrease in vascular leakage was observed in db/db mice treated with semaglutide. All these findings were observed without any change in blood glucose levels and, therefore, can be directly attributed to semaglutide. CONCLUSIONS These experimental findings point to a beneficial rather than a deleterious effect of semaglutide on the retina of subjects with diabetes.
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Lee MW, Lee WH, Ryu CK, Lee YM, Lee YH, Kim JY. Peripapillary Retinal Nerve Fiber Layer and Microvasculature in Prolonged Type 2 Diabetes Patients Without Clinical Diabetic Retinopathy. Invest Ophthalmol Vis Sci 2021; 62:9. [PMID: 33733716 PMCID: PMC7873502 DOI: 10.1167/iovs.62.2.9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose The purpose of this study to identify the effects of prolonged type 2 diabetes (T2DM) on the peripapillary retinal nerve fiber layer (pRNFL) and peripapillary microvasculature in patients with prolonged T2DM without clinical diabetic retinopathy (DR). Methods Subjects were divided into 3 groups: controls (control group; 153 eyes), patients with T2DM < 10 years (DM group 1; 136 eyes), and patients with T2DM ≥ 10 years (DM group 2; 74 eyes). The pRNFL thickness and peripapillary superficial vessel density (VD) were compared. Linear regression analyses were performed to identify factors associated with peripapillary VD in patients with T2DM. Results The mean pRNFL thicknesses of the control group, DM group 1, and DM group 2 were 96.0 ± 7.9, 94.5 ± 0.9, and 92.2 ± 8.2 µm, respectively (P < 0.001). The VDs were 18.24 ± 0.62, 17.60 ± 1.47, and 17.15 ± 1.38 mm−1 in the control group, DM group 1, and DM group 2, respectively (P < 0.001). In multivariate linear regression analyses, visual acuity (B = −2.460, P = 0.001), axial length (B = −0.169, P = 0.008), T2DM duration (B = −0.056, P < 0.001), and pRNFL (B = 0.024, P = 0.001) were significant factors affecting the peripapillary VD in patients with T2DM. Conclusions Patients with T2DM without clinical DR showed thinner pRNFL and lower peripapillary VD and perfusion density (PD) compared with normal controls, and such damage was more severe in patients with T2DM ≥ 10 years. Additionally, peripapillary VD was significantly associated with best-corrected visual acuity (BCVA), axial length, T2DM duration, and pRNFL thickness in patients with T2DM.
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Affiliation(s)
- Min-Woo Lee
- Department of Ophthalmology, Konyang University College of Medicine, Daejeon, Republic of Korea
| | - Woo-Hyuk Lee
- Department of Ophthalmology, Gyeongsang National University Changwon Hospital, Changwon, Republic of Korea
| | - Cheon-Kuk Ryu
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Yong-Min Lee
- Department of Ophthalmology, Konyang University College of Medicine, Daejeon, Republic of Korea
| | - Young-Hoon Lee
- Department of Ophthalmology, Konyang University College of Medicine, Daejeon, Republic of Korea
| | - Jung-Yeul Kim
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
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Silva M, Peng T, Zhao X, Li S, Farhan M, Zheng W. Recent trends in drug-delivery systems for the treatment of diabetic retinopathy and associated fibrosis. Adv Drug Deliv Rev 2021; 173:439-460. [PMID: 33857553 DOI: 10.1016/j.addr.2021.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/05/2021] [Accepted: 04/08/2021] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy is a frequent microvascular complication of diabetes and a major cause of visual impairment. In advanced stages, the abnormal neovascularization can lead to fibrosis and subsequent tractional retinal detachment and blindness. The low bioavailability of the drugs at the target site imposed by the anatomic and physiologic barriers within the eye, requires long term treatments with frequent injections that often compromise patient's compliance and increase the risk of developing more complications. In recent years, much effort has been put towards the development of new drug delivery platforms aiming to enhance their permeation, to prolong their retention time at the target site and to provide a sustained release with reduced toxicity and improved efficacy. This review provides an overview of the etiology and pathophysiology of diabetic retinopathy and current treatments. It addresses the specific challenges associated to the different ocular delivery routes and provides a critical review of the most recent developments made in the drug delivery field.
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Affiliation(s)
- Marta Silva
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau
| | - Tangming Peng
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau
| | - Xia Zhao
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau
| | - Shuai Li
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau
| | - Mohd Farhan
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau
| | - Wenhua Zheng
- Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau.
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Diabetic retinal neurodegeneration as a form of diabetic retinopathy. Int Ophthalmol 2021; 41:3223-3248. [PMID: 33954860 DOI: 10.1007/s10792-021-01864-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/08/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE To review the evidence supporting diabetic retinal neurodegeneration (DRN) as a form of diabetic retinopathy. METHOD Review of literature. RESULTS DRN is recognized to be a part of retinopathy in patients with diabetes mellitus (DM), in addition to the well-established diabetic retinal vasculopathy (DRV). DRN has been noted in the early stages of DM, before the onset of clinically evident diabetic retinopathy. The occurrence of DRN has been confirmed in animal models of DM, histopathological examination of donor's eyes from diabetic individuals and assessment of neural structure and function in humans. DRN involves alterations in retinal ganglion cells, photoreceptors, amacrine cells and bipolar cells, and is thought to be driven by glutamate, oxidative stress and dysregulation of neuroprotective factors in the retina. Potential therapeutic options for DRN are under evaluation. CONCLUSIONS Literature is divided on the temporal relation between DRN and DRV, with evidence of both precedence and simultaneous occurrence. The relationship between DRN and multi-system neuropathy in DM is yet to be evaluated critically.
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Nian S, Lo ACY, Mi Y, Ren K, Yang D. Neurovascular unit in diabetic retinopathy: pathophysiological roles and potential therapeutical targets. EYE AND VISION 2021; 8:15. [PMID: 33931128 PMCID: PMC8088070 DOI: 10.1186/s40662-021-00239-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 04/02/2021] [Indexed: 02/06/2023]
Abstract
Diabetic retinopathy (DR), one of the common complications of diabetes, is the leading cause of visual loss in working-age individuals in many industrialized countries. It has been traditionally regarded as a purely microvascular disease in the retina. However, an increasing number of studies have shown that DR is a complex neurovascular disorder that affects not only vascular structure but also neural tissue of the retina. Deterioration of neural retina could precede microvascular abnormalities in the DR, leading to microvascular changes. Furthermore, disruption of interactions among neurons, vascular cells, glia and local immune cells, which collectively form the neurovascular unit, is considered to be associated with the progression of DR early on in the disease. Therefore, it makes sense to develop new therapeutic strategies to prevent or reverse retinal neurodegeneration, neuroinflammation and impaired cell-cell interactions of the neurovascular unit in early stage DR. Here, we present current perspectives on the pathophysiology of DR as a neurovascular disease, especially at the early stage. Potential novel treatments for preventing or reversing neurovascular injuries in DR are discussed as well.
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Affiliation(s)
- Shen Nian
- Department of Pathology, Xi'an Medical University, Xi'an, Shaanxi Province, China.
| | - Amy C Y Lo
- Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Yajing Mi
- Institute of Basic Medicine Science, Xi'an Medical University, Xi'an, Shaanxi Province, China
| | - Kai Ren
- Department of Biochemistry and Molecular Biology, Xi'an Medical University, Xi'an, Shaanxi Province, China
| | - Di Yang
- Department of Ophthalmology, First Affiliated Hospital of Kunming Medical University, Kunming Medical University, Kunming, Yunnan Province, China.
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Oshitari T. Understanding intrinsic survival and regenerative pathways through in vivo and in vitro studies: implications for optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2021. [DOI: 10.1080/17469899.2021.1912595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Japan
- Department of Ophthalmology, International University of Health and Welfare School of Medicine, Narita, Japan
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Pan WW, Gardner TW, Harder JL. Integrative Biology of Diabetic Retinal Disease: Lessons from Diabetic Kidney Disease. J Clin Med 2021; 10:1254. [PMID: 33803590 PMCID: PMC8003049 DOI: 10.3390/jcm10061254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 01/13/2023] Open
Abstract
Diabetic retinal disease (DRD) remains the most common cause of vision loss in adults of working age. Progress on the development of new therapies for DRD has been limited by the complexity of the human eye, which constrains the utility of traditional research techniques, including animal and tissue culture models-a problem shared by those in the field of kidney disease research. By contrast, significant progress in the study of diabetic kidney disease (DKD) has resulted from the successful employment of systems biology approaches. Systems biology is widely used to comprehensively understand complex human diseases through the unbiased integration of genetic, environmental, and phenotypic aspects of the disease with the functional and structural manifestations of the disease. The application of a systems biology approach to DRD may help to clarify the molecular basis of the disease and its progression. Acquiring this type of information might enable the development of personalized treatment approaches, with the goal of discovering new therapies targeted to an individual's specific DRD pathophysiology and phenotype. Furthermore, recent efforts have revealed shared and distinct pathways and molecular targets of DRD and DKD, highlighting the complex pathophysiology of these diseases and raising the possibility of therapeutics beneficial to both organs. The objective of this review is to survey the current understanding of DRD pathophysiology and to demonstrate the investigative approaches currently applied to DKD that could promote a more thorough understanding of the structure, function, and progression of DRD.
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Affiliation(s)
- Warren W. Pan
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (W.W.P.); (T.W.G.)
| | - Thomas W. Gardner
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (W.W.P.); (T.W.G.)
- Department of Internal Medicine (Metabolism, Endocrinology and Diabetes), University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jennifer L. Harder
- Department of Internal Medicine (Nephrology), University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Damian I, Nicoară SD. Correlations between Retinal Arterial Morphometric Parameters and Neurodegeneration in Patients with Type 2 Diabetes Mellitus with No or Mild Diabetic Retinopathy. MEDICINA (KAUNAS, LITHUANIA) 2021; 57:244. [PMID: 33807881 PMCID: PMC8002138 DOI: 10.3390/medicina57030244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/18/2022]
Abstract
Background and Objectives: In patients with diabetes mellitus (DM), the neural retina is starting to degenerate before the development of vascular lesions. Our purpose was to investigate the correlation between the retinal arterial morphometric parameters and structural neurodegeneration in patients with type 2 DM with no or mild diabetic retinopathy (DR). Materials and Methods: This is a prospective study including 53 eyes of patients with type 2 DM and 32 eyes of healthy controls. Based on SD-OCT (spectral domain-optical coherence tomography) images, using a micro-densitometry method, we measured the outer and luminal diameter of retinal arteries and calculated the AWT (arterial wall thickness), WLR (wall-to-lumen ratio), and WCSA (wall cross-sectional area). GCL (ganglion cell layer) and RNFL (retinal nerve fiber layer) thickness were analyzed in correlation with the retinal arterial morphometric parameters mentioned above. Results: GCL was thinner in the inner quadrants in the NDR (no DR) group compared to controls (p < 0.05). RAOD (retinal artery outer diameter), RALD (retinal artery lumen diameter), AWT, WLR, and WCSA were similar between groups. A regression model considering age, gender, duration of DM, and HbA1C was carried out. Central GCL thickness was correlated positively with RAOD (coefficient 0.360 per µm, p = 0.011), RALD (coefficient 0.283 per µm, p = 0.050), AWT (coefficient 0.304 per µm, p = 0.029), and WCSA (coefficient 3.90 per µm, p = 0.005). Duration of DM was positively correlated with WCSA (coefficient 0.311 per one year duration of diabetes, p = 0.043). Conclusions: Significant GCL thinning in the inner quadrants preceded the morphological retinal arterial morphometric changes, supporting the neurodegeneration as primary pathogenic mechanism in DR.
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Affiliation(s)
- Ioana Damian
- Department of Ophthalmology, “Iuliu Hațieganu” University of Medicine and Pharmacy, 8 V. Babes str., 400012 Cluj-Napoca, Romania;
- Medical Doctoral School, University of Oradea, 1 Universitatii Str., 410087 Oradea, Romania
| | - Simona Delia Nicoară
- Department of Ophthalmology, “Iuliu Hațieganu” University of Medicine and Pharmacy, 8 V. Babes str., 400012 Cluj-Napoca, Romania;
- Department of Ophthalmology, Emergency County Hospital Cluj, 3–5 Clinicilor Str., 400006 Cluj-Napoca, Romania
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Targeted pharmacotherapy against neurodegeneration and neuroinflammation in early diabetic retinopathy. Neuropharmacology 2021; 187:108498. [PMID: 33582150 DOI: 10.1016/j.neuropharm.2021.108498] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/18/2021] [Accepted: 02/06/2021] [Indexed: 02/07/2023]
Abstract
Diabetic retinopathy (DR), the most frequent complication of diabetes, is one of the leading causes of irreversible blindness in working-age adults and has traditionally been regarded as a microvascular disease. However, increasing evidence has revealed that synaptic neurodegeneration of retinal ganglion cells (RGCs) and activation of glial cells may represent some of the earliest events in the pathogenesis of DR. Upon diabetes-induced metabolic stress, abnormal glycogen synthase kinase-3β (GSK-3β) activation drives tau hyperphosphorylation and β-catenin downregulation, leading to mitochondrial impairment and synaptic neurodegeneration prior to RGC apoptosis. Moreover, glial cell activation triggers enhanced inflammation and oxidative stress, which may accelerate the deterioration of diabetic RGCs neurodegeneration. These findings have opened up opportunities for therapies, such as inhibition of GSK-3β, glial cell activation, glutamate excitotoxicity and the use of neuroprotective drugs targeting early neurodegenerative processes in the retina and halting the progression of DR before the manifestation of microvascular abnormalities. Such interventions could potentially remedy early neurodegeneration and help prevent vision loss in people suffering from DR.
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Monitoring New Long-Lasting Intravitreal Formulation for Glaucoma with Vitreous Images Using Optical Coherence Tomography. Pharmaceutics 2021; 13:pharmaceutics13020217. [PMID: 33562488 PMCID: PMC7915309 DOI: 10.3390/pharmaceutics13020217] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 01/07/2023] Open
Abstract
Intravitreal injection is the gold standard therapeutic option for posterior segment pathologies, and long-lasting release is necessary to avoid reinjections. There is no effective intravitreal treatment for glaucoma or other optic neuropathies in daily practice, nor is there a non-invasive method to monitor drug levels in the vitreous. Here we show that a glaucoma treatment combining a hypotensive and neuroprotective intravitreal formulation (IF) of brimonidine–Laponite (BRI/LAP) can be monitored non-invasively using vitreoretinal interface imaging captured with optical coherence tomography (OCT) over 24 weeks of follow-up. Qualitative and quantitative characterisation was achieved by analysing the changes in vitreous (VIT) signal intensity, expressed as a ratio of retinal pigment epithelium (RPE) intensity. Vitreous hyperreflective aggregates mixed in the vitreous and tended to settle on the retinal surface. Relative intensity and aggregate size progressively decreased over 24 weeks in treated rat eyes as the BRI/LAP IF degraded. VIT/RPE relative intensity and total aggregate area correlated with brimonidine levels measured in the eye. The OCT-derived VIT/RPE relative intensity may be a useful and objective marker for non-invasive monitoring of BRI/LAP IF.
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Horton WB, Barrett EJ. Microvascular Dysfunction in Diabetes Mellitus and Cardiometabolic Disease. Endocr Rev 2021; 42:29-55. [PMID: 33125468 PMCID: PMC7846151 DOI: 10.1210/endrev/bnaa025] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Indexed: 02/07/2023]
Abstract
This review takes an inclusive approach to microvascular dysfunction in diabetes mellitus and cardiometabolic disease. In virtually every organ, dynamic interactions between the microvasculature and resident tissue elements normally modulate vascular and tissue function in a homeostatic fashion. This regulation is disordered by diabetes mellitus, by hypertension, by obesity, and by dyslipidemia individually (or combined in cardiometabolic disease), with dysfunction serving as an early marker of change. In particular, we suggest that the familiar retinal, renal, and neural complications of diabetes mellitus are late-stage manifestations of microvascular injury that begins years earlier and is often abetted by other cardiometabolic disease elements (eg, hypertension, obesity, dyslipidemia). We focus on evidence that microvascular dysfunction precedes anatomic microvascular disease in these organs as well as in heart, muscle, and brain. We suggest that early on, diabetes mellitus and/or cardiometabolic disease can each cause reversible microvascular injury with accompanying dysfunction, which in time may or may not become irreversible and anatomically identifiable disease (eg, vascular basement membrane thickening, capillary rarefaction, pericyte loss, etc.). Consequences can include the familiar vision loss, renal insufficiency, and neuropathy, but also heart failure, sarcopenia, cognitive impairment, and escalating metabolic dysfunction. Our understanding of normal microvascular function and early dysfunction is rapidly evolving, aided by innovative genetic and imaging tools. This is leading, in tissues like the retina, to testing novel preventive interventions at early, reversible stages of microvascular injury. Great hope lies in the possibility that some of these interventions may develop into effective therapies.
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Affiliation(s)
- William B Horton
- Division of Endocrinology and Metabolism, Department of Medicine
| | - Eugene J Barrett
- Division of Endocrinology and Metabolism, Department of Medicine.,Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
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Rodrigo MJ, Cardiel MJ, Fraile JM, Mendez-Martinez S, Martinez-Rincon T, Subias M, Polo V, Ruberte J, Ramirez T, Vispe E, Luna C, Mayoral JA, Garcia-Martin E. Brimonidine-LAPONITE® intravitreal formulation has an ocular hypotensive and neuroprotective effect throughout 6 months of follow-up in a glaucoma animal model. Biomater Sci 2020; 8:6246-6260. [PMID: 33016285 DOI: 10.1039/d0bm01013h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intravitreal administration is widely used in ophthalmological practice to maintain therapeutic drug levels near the neuroretina and because drug delivery systems are necessary to avoid reinjections and sight-threatening side effects. However, currently there is no intravitreal treatment for glaucoma. The brimonidine-LAPONITE® formulation was created with the aim of treating glaucoma for extended periods with a single intravitreal injection. Glaucoma was induced by producing ocular hypertension in two rat cohorts: [BRI-LAP] and [non-bri], with and without treatment, respectively. Eyes treated with brimonidine-LAPONITE® showed lower ocular pressure levels up to week 8 (p < 0.001), functional neuroprotection explored by scotopic and photopic negative response electroretinography (p = 0.042), and structural protection of the retina, retinal nerve fibre layer and ganglion cell layer (p = 0.038), especially on the superior-inferior axis explored by optical coherence tomography, which was corroborated by a higher retinal ganglion cell count (p = 0.040) using immunohistochemistry (Brn3a antibody) up to the end of the study (week 24). Furthermore, delayed neuroprotection was detected in the contralateral eye. Brimonidine was detected in treated rat eyes for up to 6 months. Brimonidine-LAPONITE® seems to be a potential sustained-delivery intravitreal drug for glaucoma treatment.
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Affiliation(s)
- M J Rodrigo
- Department of Ophthalmology, Miguel Servet University Hospital, Zaragoza, Spain.
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Simó R, Frontoni S. Neuropathic damage in the diabetic eye: clinical implications. Curr Opin Pharmacol 2020; 55:1-7. [PMID: 32932105 DOI: 10.1016/j.coph.2020.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/11/2020] [Accepted: 08/25/2020] [Indexed: 02/07/2023]
Abstract
In recent years, emerging evidence support that the eye is target of diabetes neuropathy. There are two components of the eye that are mainly involved in the neurodegenerative process induced by diabetes: the retina and the cornea. The study of functional and structural changes in these components of the eye will provide useful information to identify subjects with diabetes at risk of diabetic peripheral neuropathy and dementia. In this review the state of the art regarding the evidence and clinical implications of this emerging concept will be provided. In addition, the relationship between retinal and corneal neurodegeneration with peripheral neuropathy and cognitive decline will be analyzed. Finally, the scientific gaps than need to be covered and will be critically examined.
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Affiliation(s)
- Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBERDEM (ISCIII), Madrid, Spain.
| | - Simona Frontoni
- Unit of Endocrinology, Diabetes and Metabolism, S. Giovanni Calibita, Fate Bene Fratelli Hospital, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
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A critical review: Psychophysical assessments of diabetic retinopathy. Surv Ophthalmol 2020; 66:213-230. [PMID: 32866468 DOI: 10.1016/j.survophthal.2020.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 02/08/2023]
Abstract
Diabetic retinal disease remains a leading cause of vision loss despite currently available screening methods, ocular treatments, and efforts to control metabolic dysfunction. It is now understood that diabetes damages the entire retina and the cellular components of the neurovascular unit. Multiple studies have demonstrated impairment of various aspects of retinal function across the spectrum of retinopathy severity. Here we review these tests, the principles underlying their use, clinical data from multiple publications, the strengths and limitations of the studies, and prospects for their application to understand the pathophysiology of diabetic retinal disease and monitor its response to therapy. We focus on visual acuity, contrast sensitivity, color vision, visual field, and dark adaptation and their use to understand the pathophysiology of diabetic retinopathy and as potential endpoints for clinical trials.
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Effect of Topical Administration of Somatostatin on Retinal Inflammation and Neurodegeneration in an Experimental Model of Diabetes. J Clin Med 2020; 9:jcm9082579. [PMID: 32784955 PMCID: PMC7463891 DOI: 10.3390/jcm9082579] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/25/2020] [Accepted: 08/04/2020] [Indexed: 12/11/2022] Open
Abstract
Somatostatin (SST) is a neuroprotective peptide but little is known regarding the potential role of its anti-inflammatory effects on retinal neuroprotection. In a previous study, we provided the first evidence that topical (eye drops) administration of SST prevents retinal neurodegeneration in streptozotocin (STZ)-induced diabetic rats. However, STZ by itself could cause neurotoxicity, thus acting as a confounding factor. The aims of the present study were: (1) to test the effect of topical administration of SST in the db/db mouse model, a spontaneous model of type 2 diabetes, thus avoiding the confounding effect of STZ on neurodegeneration; (2) to further explore the anti-inflammatory mechanisms of SST in glial cells. This task was performed by using mouse retinal explants and cell cultures. In summary, we confirm that SST topically administered was able to prevent retinal neurodysfunction and neurodegeneration in db/db mice. Furthermore, we found that SST prevented the activation of the classical M1 response of Bv.2 microglial cells upon Lipopolysaccharide (LPS) stimulation as a potent pro-inflammatory trigger. The anti-inflammatory effect of SST in Bv.2 cells was also observed in response to hypoxia. In conclusion, we provide evidence that the neuroprotective effect of SST in diabetic retinas can be largely attributed to anti-inflammatory mechanisms.
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