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Abokyi S, Tse DYY. Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy. Neural Regen Res 2025; 20:366-377. [PMID: 38819040 PMCID: PMC11317960 DOI: 10.4103/nrr.nrr-d-23-02033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/08/2024] [Accepted: 03/07/2024] [Indexed: 06/01/2024] Open
Abstract
Retinal aging has been recognized as a significant risk factor for various retinal disorders, including diabetic retinopathy, age-related macular degeneration, and glaucoma, following a growing understanding of the molecular underpinnings of their development. This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches, focusing on the activation of transcription factor EB. Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies, such as exercise, calorie restriction, rapamycin, and metformin, in patients and animal models of these common retinal diseases. The review critically assesses the role of transcription factor EB in retinal biology during aging, its neuroprotective effects, and its therapeutic potential for retinal disorders. The impact of transcription factor EB on retinal aging is cell-specific, influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways. In vascular endothelial cells, transcription factor EB controls important processes, including endothelial cell proliferation, endothelial tube formation, and nitric oxide levels, thereby influencing the inner blood-retinal barrier, angiogenesis, and retinal microvasculature. Additionally, transcription factor EB affects vascular smooth muscle cells, inhibiting vascular calcification and atherogenesis. In retinal pigment epithelial cells, transcription factor EB modulates functions such as autophagy, lysosomal dynamics, and clearance of the aging pigment lipofuscin, thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization. These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis, neuronal synapse plasticity, energy metabolism, microvasculature, and inflammation, ultimately offering protection against retinal aging and diseases. The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases. Therefore, it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects.
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Affiliation(s)
- Samuel Abokyi
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China
- Research Center for SHARP Vision, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China
| | - Dennis Yan-yin Tse
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China
- Research Center for SHARP Vision, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China
- Center for Eye and Vision Research, Sha Tin, Hong Kong Special Administrative Region, China
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2
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Araujo VG, Alexandrino-Mattos DP, Marinho TP, Linden R, Petrs-Silva H. Longitudinal evaluation of morphological, functional and vascular alterations in a rat model of experimental glaucoma. Vision Res 2024; 223:108458. [PMID: 39079282 DOI: 10.1016/j.visres.2024.108458] [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: 05/26/2024] [Revised: 07/10/2024] [Accepted: 07/10/2024] [Indexed: 09/09/2024]
Abstract
Glaucoma, the leading cause of irreversible blindness worldwide, is a neurodegenerative disease characterized by chronic axonal damages and progressive loss of retinal ganglion cells, with increased intraocular pressure (IOP) as the primary risk factor. While current treatments focus solely on reducing IOP, understanding glaucoma through experimental models is essential for developing new therapeutic strategies and biomarkers for early diagnosis. Our research group developed an ocular hypertension rat model based on limbal plexus cautery, which provides significant glaucomatous neurodegeneration up to four weeks after injury. We evaluated long-term morphological, functional, and vascular alterations in this model. Our results showed that transient ocular hypertension, lasting approximately one week, can lead to progressive increase in optic nerve cupping and retinal ganglion cells loss. Remarkably, the pressure insult caused several vascular changes, such as arteriolar and venular thinning, and permanent choroidal vascular swelling. This study provides evidence of the longitudinal effects of a pressure insult on retinal structure and function using clinical modalities and techniques. The multifactorial changes reported in this model resemble the complex retinal ganglion cell degeneration found in glaucoma patients, and therefore may also provide a unique tool for the development of novel interventions to either halt or slow down disease progression.
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Affiliation(s)
- Victor G Araujo
- Laboratory of Gene Therapy and Viral Vector, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dio P Alexandrino-Mattos
- Laboratory of Gene Therapy and Viral Vector, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thais P Marinho
- Laboratory of Gene Therapy and Viral Vector, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael Linden
- Laboratory of Neurogenesis, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hilda Petrs-Silva
- Laboratory of Gene Therapy and Viral Vector, Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Ni Y, Hu Y, Zhu L, Jiang X, Zhang H, Liu J, Zhao Y. Lycium Barbarum Polysaccharide-Derived Nanoparticles Protect Visual Function by Inhibiting RGC Ferroptosis and Microglial Activation in Retinal Ischemia‒Reperfusion Mice. Adv Healthc Mater 2024; 13:e2304285. [PMID: 38994661 DOI: 10.1002/adhm.202304285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 06/16/2024] [Indexed: 07/13/2024]
Abstract
Retinal ischemia‒reperfusion (IR) is a major contributor to vision impairment and irreversible vision loss due to retinal ganglion cell (RGC) injury or loss. Contemporary therapeutic approaches predominantly focus on the amelioration of symptoms rather than addressing the fundamental etiological factors. Oxidative stress is a notable feature and an important mediator of IR damage. Lycium barbarum polysaccharide (LBP), the main active ingredient of Lycium barbarum, has various pharmacological effects, including antioxidation, immunoregulation, and neuroprotective effects. In this study, the ROS-consumable moiety phenylboronic acid pinacol ester (PBA) is introduced to LBP molecules, which can self-assemble into nanoparticles in aqueous solution. This nanoparticle (termed PLBP) can reduce the cellular ROS levels and enhance the antioxidant capability of RGCs by activating the NRF2 pathway, thus protecting RGCs from ferroptosis and preserving visual function in response to IR injury. PLBP also reduces neuroinflammation by inhibiting the ability of microglia to phagocytose, migrate, secrete inflammatory cytokines, and activate the NF-κB pathway. In conclusion, this approach can be used as an inspiration for the future development of neuroprotective drugs.
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Affiliation(s)
- Yueqi Ni
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yuanyuan Hu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lijia Zhu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xulin Jiang
- Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry, Wuhan University, Wuhan, 430072, China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia Liu
- Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yin Zhao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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Lee JS, Kim CZ, Lee SU, Lee SJ. Choroidal Thickening Induced by Pioglitazone in Diabetic Patients. KOREAN JOURNAL OF OPHTHALMOLOGY 2024; 38:331-341. [PMID: 39155138 DOI: 10.3341/kjo.2024.0039] [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: 03/19/2024] [Accepted: 07/30/2024] [Indexed: 08/20/2024] Open
Abstract
PURPOSE This study aimed to determine the changes in choroidal thickness induced by pioglitazone in diabetic patients. METHODS A total of 261 patients diagnosed with type 2 diabetes who had taken oral pioglitazone for more than 6 months were included in the study. After excluding patients who did not undergo regular eye examinations or who had ophthalmic surgery/interventions during the treatment period, a total of 40 eyes were included. The study examined the duration and dosage of pioglitazone, patient age, ocular axial length, refraction, glycated hemoglobin, systolic blood pressure, corrected visual acuity, macular thickness, choroidal thickness, and choroidal vascular index. Patients were categorized into a high-dose group if their pioglitazone dose was 30 mg or more per day, and a low-dose group if it was 15 mg or less. Choroidal thickness was measured below the subfovea and a 500 µm radius nasal and temporal to that location. RESULTS Choroidal thickness significantly increased after 6 and 12 months of pioglitazone (6.70 and 13.65 µm, respectively) in all subjects. When stratified by pioglitazone dosage, choroidal thickness increased at 6 and 12 months in both high-dose group (4.48 and 0.84 µm, respectively) and low-dose groups (6.85 and 21.45 µm, respectively), with a greater change observed in the low-dose group (p < 0.05). Based on the location of choroidal thickness measurements, a significant increase in choroidal thickness was observed at 6 and 12 months of pioglitazone treatment in the subfoveal (7.00 and 13.15 µm, respectively) and nasal regions (6.43 and 19.24 µm, respectively), while a significant increase was only observed after 6 months of treatment in the temporal region (8.53 µm, p < 0.05). The largest increase in choroidal thickness was observed in the nasal side. CONCLUSIONS This study found that choroidal thickness increased in diabetic patients after taking pioglitazone. Regular eye examinations are recommended for diabetic patients who are on pioglitazone.
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Affiliation(s)
- Ju Seouk Lee
- Department of Ophthalmology, Kosin University College of Medicine, Busan, Korea
| | - Chang Zoo Kim
- Department of Ophthalmology, Kosin University College of Medicine, Busan, Korea
| | - Seung Uk Lee
- Department of Ophthalmology, Kosin University College of Medicine, Busan, Korea
| | - Sang Joon Lee
- Department of Ophthalmology, Kosin University College of Medicine, Busan, Korea
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Elbedwehy AM, Wu J, Na HK, Baek A, Jung H, Kwon IH, Lee SW, Kim JH, Lee TG. ROS-responsive charge reversal mesoporous silica nanoparticles as promising drug delivery system for neovascular retinal diseases. J Control Release 2024; 373:224-239. [PMID: 39002796 DOI: 10.1016/j.jconrel.2024.07.022] [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: 11/25/2023] [Revised: 06/25/2024] [Accepted: 07/08/2024] [Indexed: 07/15/2024]
Abstract
Intravitreal injection of biodegradable implant drug carriers shows promise in reducing the injection frequency for neovascular retinal diseases. However, current intravitreal ocular devices have limitations in adjusting drug release rates for individual patients, thereby affecting treatment effectiveness. Accordingly, we developed mesoporous silica nanoparticles (MSNs) featuring a surface that reverse its charge in response to reactive oxygen species (ROS) for efficient delivery of humanin peptide (HN) to retinal epithelial cells (ARPE-19). The MSN core, designed with a pore size of 2.8 nm, ensures a high HN loading capacity 64.4% (w/w). We fine-tuned the external surface of the MSNs by incorporating 20% Acetyl-L-arginine (Ar) to create a partial positive charge, while 80% conjugated thioketal (TK) methoxy polyethylene glycol (mPEG) act as ROS gatekeeper. Ex vivo experiments using bovine eyes revealed the immobilization of Ar-MSNs-TK-PEG (mean zeta potential: 2 mV) in the negatively charged vitreous. However, oxidative stress reversed the surface charge to -25 mV by mPEG loss, facilitating the diffusion of the nanoparticles impeded with HN. In vitro studies showed that ARPE-19 cells effectively internalize HN-loaded Ar-MSNs-TK, subsequently releasing the peptide, which offered protection against oxidative stress-induced apoptosis, as evidenced by reduced TUNEL and caspase3 activation. The inhibition of retinal neovascularization was further validated in an in vivo oxygen-induced retinopathy (OIR) mouse model.
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Affiliation(s)
- Ahmed M Elbedwehy
- Department of Nano Science, Korea National University of Science and Technology (UST), Daejeon 34113, Republic of Korea; Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea; Nanotechnology Center, Mansoura University, Mansoura 35516, Egypt
| | - Jun Wu
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hee-Kyung Na
- Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Ahruem Baek
- Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Haejin Jung
- Flow Cytometry Core Facility of Research Solution Center, Institute of Basic Science, Daejeon 34126, Republic of Korea
| | - Ik Hwan Kwon
- Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Sang Won Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Ophthalmology, Seoul National University Hospital, Seoul 03080, Republic of Korea; Global Excellence Center for Gene & Cell Therapy (GEC-GCT), Seoul National University Hospital, Seoul 03080, Republic of Korea; Institute of Reproductive Medicine and Population, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
| | - Tae Geol Lee
- Department of Nano Science, Korea National University of Science and Technology (UST), Daejeon 34113, Republic of Korea; Safety Measurement Institute, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea.
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Gui Y, Gui S, Wang X, Li Y, Xu Y, Zhang J. Exploring the relationship between heavy metals and diabetic retinopathy: a machine learning modeling approach. Sci Rep 2024; 14:13049. [PMID: 38844504 PMCID: PMC11156935 DOI: 10.1038/s41598-024-63916-w] [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: 03/28/2024] [Accepted: 06/03/2024] [Indexed: 06/09/2024] Open
Abstract
Diabetic retinopathy (DR) is one of the leading causes of adult blindness in the United States. Although studies applying traditional statistical methods have revealed that heavy metals may be essential environmental risk factors for diabetic retinopathy, there is a lack of analyses based on machine learning (ML) methods to adequately explain the complex relationship between heavy metals and DR and the interactions between variables. Based on characteristic variables of participants with and without DR and heavy metal exposure data obtained from the NHANES database (2003-2010), a ML model was developed for effective prediction of DR. The best predictive model for DR was selected from 11 models by receiver operating characteristic curve (ROC) analysis. Further permutation feature importance (PFI) analysis, partial dependence plots (PDP) analysis, and SHapley Additive exPlanations (SHAP) analysis were used to assess the model capability and key influencing factors. A total of 1042 eligible individuals were randomly assigned to two groups for training and testing set of the prediction model. ROC analysis showed that the k-nearest neighbour (KNN) model had the highest prediction performance, achieving close to 100% accuracy in the testing set. Urinary Sb level was identified as the critical heavy metal affecting the predicted risk of DR, with a contribution weight of 1.730632 ± 1.791722, which was much higher than that of other heavy metals and baseline variables. The results of the PDP analysis and the SHAP analysis also indicated that antimony (Sb) had a more significant effect on DR. The interaction between age and Sb was more significant compared to other variables and metal pairs. We found that Sb could serve as a potential predictor of DR and that Sb may influence the development of DR by mediating cellular and systemic senescence. The study revealed that monitoring urinary Sb levels can be useful for early non-invasive screening and intervention in DR development, and also highlighted the important role of constructed ML models in explaining the effects of heavy metal exposure on DR.
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Affiliation(s)
- Yanchao Gui
- Department of Ophthalmology, Anqing Second People's Hospital, 79 Guanyuemiao Street, Anqing, 246004, China
| | - Siyu Gui
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, 678 Furong Road, Hefei, 230601, China
| | - Xinchen Wang
- Department of Ophthalmology, The Second Affiliated Hospital of Anhui Medical University, 678 Furong Road, Hefei, 230601, China
| | - Yiran Li
- Department of Clinical Medicine, The Second School of Clinical Medicine, Anhui Medical University, 81 Meishan Road, Hefei, 230032, China
| | - Yueyang Xu
- Department of Clinical Medicine, The First School of Clinical Medicine, Anhui Medical University, 81 Meishan Road, Hefei, 230032, China
| | - Jinsong Zhang
- Department of Ophthalmology, Anqing Second People's Hospital, 79 Guanyuemiao Street, Anqing, 246004, China.
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Cui X, Buonfiglio F, Pfeiffer N, Gericke A. Aging in Ocular Blood Vessels: Molecular Insights and the Role of Oxidative Stress. Biomedicines 2024; 12:817. [PMID: 38672172 PMCID: PMC11048681 DOI: 10.3390/biomedicines12040817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
Acknowledged as a significant pathogenetic driver for numerous diseases, aging has become a focal point in addressing the profound changes associated with increasing human life expectancy, posing a critical concern for global public health. Emerging evidence suggests that factors influencing vascular aging extend their impact to choroidal and retinal blood vessels. The objective of this work is to provide a comprehensive overview of the impact of vascular aging on ocular blood vessels and related diseases. Additionally, this study aims to illuminate molecular insights contributing to vascular cell aging, with a particular emphasis on the choroid and retina. Moreover, innovative molecular targets operating within the domain of ocular vascular aging are presented and discussed.
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Affiliation(s)
- Xiuting Cui
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (F.B.); (N.P.)
| | | | | | - Adrian Gericke
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (F.B.); (N.P.)
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Liu Y, Liu Y, Wang X, Xiu C, Hu Y, Wang J, Lei Y, Yang J. Ginseng-Sanqi-Chuanxiong (GSC) extracts attenuate d-galactose-induced vascular aging in mice via inhibition of endothelial progenitor cells senescence. Heliyon 2024; 10:e25253. [PMID: 38404901 PMCID: PMC10884806 DOI: 10.1016/j.heliyon.2024.e25253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/21/2024] [Accepted: 01/23/2024] [Indexed: 02/27/2024] Open
Abstract
Vascular aging is an independent risk factor for age-related diseases and a specific type of organic aging. Endothelial progenitor cells (EPCs), a type of bone marrow stem cell, has been linked to vascular aging. The purpose of this study is to investigate if Ginseng-Sanqi-Chuanxiong (GSC) extract, a traditional Chinese medicine, can delay aortic aging in mice by enhancing the performance and aging of EPCs in vivo and to analyze the potential mechanisms through a d-Galactose (D-gal)-induced vascular aging model in mice. Our study revealed that GSC extracts not only enhanced the aortic structure, endothelial function, oxidative stress levels, and aging in mice, but also enhanced the proliferation, migration, adhesion, and secretion of EPCs in vivo, while reducing the expression of p53, p21, and p16. To conclude, GSC can delay vascular senescence by enhancing the function and aging of EPCs, which could be linked to a decrease in p16 and p53/p21 signaling. Consequently, utilizing GSC extracts to enhance the function and senescence of autologous EPCs may present a novel avenue for enhancing autologous stem cells in alleviating senescence.
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Affiliation(s)
- Yinan Liu
- Graduate School of China Academy of Chinese Medical Sciences, Beijing, China
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yiqing Liu
- National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xue Wang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Chengkui Xiu
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanhong Hu
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jiali Wang
- Tianjin Academy of Traditional Chinese Medicine, Tianjin, China
| | - Yan Lei
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jing Yang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
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Yu PK, Mehnert A, Dickson JB, Qambari H, Balaratnasingam C, Cringle S, Darcey D, Yu DY. Quantitative study of spatial and temporal variation in retinal capillary network perfusion in rat eye by in vivo confocal imaging. Sci Rep 2023; 13:18923. [PMID: 37919331 PMCID: PMC10622421 DOI: 10.1038/s41598-023-44480-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/09/2023] [Indexed: 11/04/2023] Open
Abstract
Microvascular dysfunction is the underlying pathological process in many systemic diseases. However, investigation into its pathogenesis is impeded by the accessibility and complexity of the microvasculature within different organs, particularly for the central nervous system. The retina as an extension of the cerebrum provides a glimpse into the brain through which the microvasculature can be observed. Two major questions remain unanswered: How do the microvessels regulate spatial and temporal delivery to satisfy the varying cellular demands, and how can we quantify blood perfusion in the 3D capillary network? Here, quantitative measurements of red blood cell (RBC) speed in each vessel in the field were made in the in vivo rat retinal capillary network using an ultrafast confocal technique with fluorescently labelled RBCs. Retinal RBC speed and number were found to vary remarkably between microvessels ranging from 215 to 6641 microns per second with significant variations spatially and temporally. Overall, the RBC speed was significantly faster in the microvessels in the superficial retina than in the deep retina (estimated marginal means of 2405 ± 238.2 µm/s, 1641 ± 173.0 µm/s respectively). These observations point to a highly dynamic nature of microvasculature that is specific to its immediate cellular environment and is constantly changing.
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Affiliation(s)
- Paula Kun Yu
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
| | - Andrew Mehnert
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
| | | | - Hassanain Qambari
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
- Department of Ophthalmology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - Stephen Cringle
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
| | - Dean Darcey
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia
| | - Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia.
- Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia.
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