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Ghorbani R, Rasouli M, Sefat F, Heidari Keshel S. Pathogenesis of Common Ocular Diseases: Emerging Trends in Extracellular Matrix Remodeling. Semin Ophthalmol 2024; 39:27-39. [PMID: 37424085 DOI: 10.1080/08820538.2023.2233601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/27/2023] [Accepted: 07/02/2023] [Indexed: 07/11/2023]
Abstract
The prevalence of visual impairments in human societies is worrying due to retinopathy complications of several chronic diseases such as diabetes, cardiovascular diseases, and many more that are on the rise worldwide. Since the proper function of this organ plays a pivotal role in people's quality of life, identifying factors affecting the development/exacerbation of ocular diseases is of particular interest among ophthalmology researchers. The extracellular matrix (ECM) is a reticular, three-dimensional (3D) structure that determines the shape and dimensions of tissues in the body. The ECM remodeling/hemostasis is a critical process in both physiological and pathological conditions. It consists of ECM deposition, degradation, and decrease/increase in the ECM components. However, disregulation of this process and an imbalance between the synthesis and degradation of ECM components are associated with many pathological situations, including ocular disorders. Despite the impact of ECM alterations on the development of ocular diseases, there is not much research conducted in this regard. Therefore, a better understanding in this regard, can pave the way toward discovering plausible strategies to either prevent or treat eye disorders. In this review, we will discuss the importance of ECM changes as a sentimental factor in various ocular diseases based on the research done up to now.
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Affiliation(s)
- Raziyeh Ghorbani
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Rasouli
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farshid Sefat
- Department of Biomedical and Electronics Engineering, School of Engineering, University of Bradford, Bradford, UK
- Interdisciplinary Research Centre in Polymer Science & Technology (Polymer IRC), University of Bradford, Bradford, UK
| | - Saeed Heidari Keshel
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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2
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Zu H, Zhang K, Zhang H, Qian X. An Inverse Method to Determine Mechanical Parameters of Porcine Vitreous Bodies Based on the Indentation Test. Bioengineering (Basel) 2023; 10:646. [PMID: 37370577 DOI: 10.3390/bioengineering10060646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
The vitreous body keeps the lens and retina in place and protects these tissues from physical insults. Existing studies have reported that the mechanical properties of vitreous body varied after liquefaction, suggesting mechanical properties could be effective parameters to identify vitreous liquefaction process. Thus, in this work, we aimed to propose a method to determine the mechanical properties of vitreous bodies. Fresh porcine eyes were divided into three groups, including the untreated group, the 24 h liquefaction group and the 48 h liquefaction group, which was injected collagenase and then kept for 24 h or 48 h. The indentation tests were carried out on the vitreous body in its natural location while the posterior segment of the eye was fixed in the container. A finite element model of a specimen undertaking indentation was constructed to simulate the indentation test with surface tension of vitreous body considered. Using the inverse method, the mechanical parameters of the vitreous body and the surface tension coefficient were determined. For the same parameter, values were highest in the untreated group, followed by the 24 h liquefaction group and the lowest in the 48 h liquefaction group. For C10 in the neo-Hookean model, the significant differences were found between the untreated group and liquefaction groups. This work quantified vitreous body mechanical properties successfully using inverse method, which provides a new method for identifying vitreous liquefactions related studies.
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Affiliation(s)
- Haicheng Zu
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
| | - Kunya Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Xiuqing Qian
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
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3
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Schulz A, Wakili P, Januschowski K, Heinz WR, Engelhard M, Menz H, Szurman P. Safety and performance assessment of hyaluronic acid-based vitreous substitutes in patients with phthisis bulbi. Acta Ophthalmol 2023. [PMID: 36912796 DOI: 10.1111/aos.15658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/05/2023] [Accepted: 02/26/2023] [Indexed: 03/14/2023]
Abstract
PURPOSE To assess the safety and performance of hyaluronic acid-based vitreous substitutes in phthitic eyes. METHODS In this retrospective interventional study a total of 21 eyes from 21 patients with phthisis bulbi were treated at the Eye Clinic Sulzbach between August 2011 and June 2021. Patients who underwent a 23G pars plana vitrectomy received a vitreous substitute composed of (I) a non-crosslinked hyaluronic acid (Healon GV), (II) a crosslinked hyaluronic acid-based hydrogel (UVHA), or (III) silicone oil (SO-5000). Main outcome measures were the intraocular pressure (IOP), the visual acuity and the structural integrity of the retina and choroid assessed by optical coherence tomography. RESULTS An increase in IOP ≥ 5 mmHg was achieved with SO-5000 in 5/8 eyes (6/10 interventions, 60.0%) for 36.4 ± 39.5 days, with Healon GV in 4/8 eyes (7/11 interventions, 63.6%) for 82.6 ± 92.5 days and with UVHA in 4/5 eyes (5/6 interventions, 83.3%) for 93.6 ± 92.5 days. Visual acuity increased in 5/21 eyes (23.8%), remained constant in 12/21 eyes (57.1%) and decreased in 4/21 eyes (19.0%). No enucleations were required during the mean follow-up time of 192 ± 182 days. The OCT images indicated the preservation of retinal structures, while choroidal folds were only diminished in UVHA eyes. CONCLUSIONS Hyaluronic acid-based hydrogels are biocompatible vitreous substitutes in humans and can increase and stabilize IOP in patients with phthisis bulbi for about 3 months.
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Affiliation(s)
- André Schulz
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Philip Wakili
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
| | - Kai Januschowski
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | | | | | | | - Peter Szurman
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
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4
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Zhang P, Yan W, Yan H. Changes in the vitreous body after experimental vitreous hemorrhage in rabbit: An interdisciplinary study. PLoS One 2023; 18:e0281165. [PMID: 36745670 PMCID: PMC9901783 DOI: 10.1371/journal.pone.0281165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 01/16/2023] [Indexed: 02/07/2023] Open
Abstract
PURPOSE To explore the changes in vitreous body after vitreous hemorrhage and assess its prognosis from the perspective of vitreoretinal interface. METHODS The experiment was performed on 32 New Zealand rabbits (64 eyes), weighing 2500-3000 g for 4 months and unlimited gender, which was injected with 0.2 mL of autologous blood into the center of vitreous cavity-the study group (right eyes), and the control one was treated in the same manner with equal volumes of saline. The rabbits were randomly and equally divided into the following four batches according to the days of observation: Days 3, 7, 14, and 30 after injection. IOP and severity grading were evaluated before rabbits' execution and eyeballs were enucleated. The anterior segment was separated to flow out the vitreous body naturally to detect the liquefaction degree and viscosity. Then, chemical composition of electrolytes, PCT and bFGF were determined by colorimetry and enzyme-linked immunosorbent assay (ELISA). Finally, the incidence of posterior vitreous detachment (PVD) was observed after vitreous sampled. The studies were double-blind. RESULTS After injection, the extent of vitreous opacity and coagulum size decreased over time. Both the degree of liquefaction and the length of tow differed significantly between two groups at different time points (all p < 0.001). The liquefaction degree in the study group rose obviously from the Day 14, which the viscosity declined significantly on the initial time. Biochemical markers fluctuated temporarily, except for basic fibroblast growth factor (bFGF), which continued to rise and was correlated with the liquefaction degree (r = 0.658, p < 0.001). Besides, the incidence of PVD increased from the 14th day (p < 0.05), and it was highly positively correlated with the number of macrophages (r = 0.934; p < 0.001). CONCLUSION After vitreous hemorrhage, the changes of the vitreous body are relatively minor earlier (2-4 weeks), but irreversible later. Specifically, the degree of liquefaction increases with a decrease in viscosity, and the chemotaxis of macrophages and bFGF induce incomplete PVD.
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Affiliation(s)
- Pengcheng Zhang
- Xi’an People’s Hospital (Xi’an Fourth Hospital), Shaanxi Eye Hospital, Affiliated Xi’an Fourth Hospital, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- Department of Ophthalmology, General Hospital of Central Theater Command, PLA, Wuhan, Hubei, China
| | - Weijia Yan
- Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany
| | - Hong Yan
- Xi’an People’s Hospital (Xi’an Fourth Hospital), Shaanxi Eye Hospital, Affiliated Xi’an Fourth Hospital, Northwestern Polytechnical University, Xi’an, Shaanxi, China
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5
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Luo RH, Tram NK, Parekh AM, Puri R, Reilly MA, Swindle-Reilly KE. The Roles of Vitreous Biomechanics in Ocular Disease, Biomolecule Transport, and Pharmacokinetics. Curr Eye Res 2023; 48:195-207. [PMID: 35179421 DOI: 10.1080/02713683.2022.2033271] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE The biomechanical properties of the vitreous humor and replication of these properties to develop substitutes for the vitreous humor have rapidly become topics of interest over the last two decades. In particular, the behavior of the vitreous humor as a viscoelastic tissue has been investigated to identify its role in a variety of processes related to biotransport, aging, and age-related pathologies of the vitreoretinal interface. METHODS A thorough search and review of peer-reviewed publications discussing the biomechanical properties of the vitreous humor in both human and animal specimens was conducted. Findings on the effects of biomechanics on vitreoretinal pathologies and vitreous biotransport were analyzed and discussed. RESULTS The pig and rabbit vitreous have been found to be most mechanically similar to the human vitreous. Age-related liquefaction of the vitreous creates two mechanically unique phases, with an overall effect of softening the vitreous. However, the techniques used to acquire this mechanical data are limited by the in vitro testing methods used, and the vitreous humor has been hypothesized to behave differently in vivo due in part to its swelling properties. The impact of liquefaction and subsequent detachment of the vitreous humor from the posterior retinal surface is implicated in a variety of tractional pathologies of the retina and macula. Liquefaction also causes significant changes in the biotransport properties of the eye, allowing for significantly faster movement of molecules compared to the healthy vitreous. Recent developments in computational and ex vivo models of the vitreous humor have helped with understanding its behavior and developing materials capable of replacing it. CONCLUSIONS A better understanding of the biomechanical properties of the vitreous humor and how these relate to its structure will potentially aid in improving clinical metrics for vitreous liquefaction, design of biomimetic vitreous substitutes, and predicting pharmacokinetics for intravitreal drug delivery.
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Affiliation(s)
- Richard H Luo
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Nguyen K Tram
- Center for Regenerative Medicine, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Ankur M Parekh
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Raima Puri
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Matthew A Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
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6
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Wolf J, Sabage LE, Sun YJ, Mahajan VB. Protocol to quantify enzymatic effects on vitreous liquefaction in porcine eyes using a transwell-plate system. STAR Protoc 2022; 3:101754. [PMID: 36208453 PMCID: PMC9562426 DOI: 10.1016/j.xpro.2022.101754] [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: 07/27/2022] [Revised: 08/18/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022] Open
Abstract
This protocol describes an ex vivo model to quantify enzymatic effects on vitreous liquefaction using porcine eyes in a transwell-plate system via induced syneresis. It provides a standardized dissection process and performs critical steps for gel-liquid separation with high precision, minimal tissue loss, and scalability. The protocol can be applied to other studies investigating vitreous liquefaction or gelatinous tissue analysis and can also serve to study vitreous liquefaction in vivo as it may occur during aging or disease progression.
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Affiliation(s)
- Julian Wolf
- Molecular Surgery Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, CA 94304, USA
| | - Luís E. Sabage
- Molecular Surgery Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, CA 94304, USA,Medical Course, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo 17012-901, Brazil
| | - Young Joo Sun
- Molecular Surgery Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, CA 94304, USA
| | - Vinit B. Mahajan
- Molecular Surgery Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, CA 94304, USA,Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA,Corresponding author
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7
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Srikantha N, Teijeiro-Gonzalez Y, Simpson A, Elsaid N, Somavarapu S, Suhling K, Jackson TL. Determining vitreous viscosity using fluorescence recovery after photobleaching. PLoS One 2022; 17:e0261925. [PMID: 35143514 PMCID: PMC8830689 DOI: 10.1371/journal.pone.0261925] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 12/14/2021] [Indexed: 01/22/2023] Open
Abstract
PURPOSE Vitreous humor is a complex biofluid whose composition determines its structure and function. Vitreous viscosity will affect the delivery, distribution, and half-life of intraocular drugs, and key physiological molecules. The central pig vitreous is thought to closely match human vitreous viscosity. Diffusion is inversely related to viscosity, and diffusion is of fundamental importance for all biochemical reactions. Fluorescence Recovery After Photobleaching (FRAP) may provide a novel means of measuring intravitreal diffusion that could be applied to drugs and physiological macromolecules. It would also provide information about vitreous viscosity, which is relevant to drug elimination, and delivery. METHODS Vitreous viscosity and intravitreal macromolecular diffusion of fluorescently labelled macromolecules were investigated in porcine eyes using fluorescence recovery after photobleaching (FRAP). Fluorescein isothiocyanate conjugated (FITC) dextrans and ficolls of varying molecular weights (MWs), and FITC-bovine serum albumin (BSA) were employed using FRAP bleach areas of different diameters. RESULTS The mean (±standard deviation) viscosity of porcine vitreous using dextran, ficoll and BSA were 3.54 ± 1.40, 2.86 ± 1.13 and 4.54 ± 0.13 cP respectively, with an average of 3.65 ± 0.60 cP. CONCLUSIONS FRAP is a feasible and practical optical method to quantify the diffusion of macromolecules through vitreous.
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Affiliation(s)
- Nishanthan Srikantha
- School of Medicine, King’s College London, London, United Kingdom
- Department of Ophthalmology, King’s College Hospital, London, United Kingdom
- * E-mail:
| | | | - Andrew Simpson
- School of Medicine, King’s College London, London, United Kingdom
- Department of Ophthalmology, King’s College Hospital, London, United Kingdom
| | - Naba Elsaid
- Anglia Ruskin University, Bishop Hall Lane, Chelmsford, United Kingdom
| | - Satyanarayana Somavarapu
- Department of Pharmaceutics, University College London School of Pharmacy, London, United Kingdom
| | - Klaus Suhling
- Department of Physics, King’s College London, Strand, London, United Kingdom
| | - Timothy L. Jackson
- School of Medicine, King’s College London, London, United Kingdom
- Department of Ophthalmology, King’s College Hospital, London, United Kingdom
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8
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Hyaluronic acid in ocular drug delivery. Carbohydr Polym 2021; 264:118006. [DOI: 10.1016/j.carbpol.2021.118006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/12/2022]
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9
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Dong N, Cai Q, Li Z, Xu L, Wu H, Lin Z, Qiu B, Li C, Lin Z. Convenient hyaluronidase biosensors based on the target-trigger enhancing of the permeability of a membrane using an electronic balance as a readout. Analyst 2021; 146:3299-3304. [PMID: 33999089 DOI: 10.1039/d1an00257k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The change in hyaluronidase (HAase) is related to specific changes in the structure of vitreous, and it is necessary to develop simple but sensitive methods for HAase detection. In this work, a thin film fabricated from a hyaluronic acid (HA)-polyethyleneimine (PEI) hydrogel has been covered on a mixed cellulose microporous membrane (MCEM) to form a HA-PEI-MCEM firstly and it was then applied in a filtration system. The permeability of the filter membrane greatly affects the amount of water passing through within a certain time and the water can be collected and quantitatively measured with a simple electronic balance easily. The low permeability of the HA-PEI-MCEM allows a small amount of water to be drained. But after the addition of HAase, which can hydrolyze HA in the hydrogel, the permeability of the membrane increased. Therefore, the amount of water passing through the HA-PEI-MCEM composite membrane increased accordingly. The composite of the membrane, and the reaction conditions after the addition of HAase were optimized. Under the optimized conditions, the amount of water collected within 5 min showed a linear relationship with the HAase concentration in a range of 1.0-36 U mL-1 with a limit of detection of 0.35 U mL-1.The proposed method has been applied to detect HAase in vitreous samples with satisfactory results.
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Affiliation(s)
- Nuo Dong
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China. and Department of Ophthalmology, Affiliated People's Hospital & Zhenjiang Kangfu Eye Hospital, Jiangsu University, Zhenjiang, Jiangsu, China and Fujian Provincial Key Laboratory of Ocular Surface and Corneal Disease, Xiamen, Fujian, China
| | - Qing Cai
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Zhixin Li
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
| | - Liangzhen Xu
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Huping Wu
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China. and Fujian Provincial Key Laboratory of Ocular Surface and Corneal Disease, Xiamen, Fujian, China
| | - Zhirong Lin
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China. and Fujian Provincial Key Laboratory of Ocular Surface and Corneal Disease, Xiamen, Fujian, China
| | - Bin Qiu
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
| | - Cheng Li
- Eye Institute & Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Zhenyu Lin
- Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
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10
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Levin M, Cohen N. The effects of aging on the mechanical properties of the vitreous. J Biomech 2021; 119:110310. [PMID: 33721627 DOI: 10.1016/j.jbiomech.2021.110310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/22/2021] [Accepted: 02/03/2021] [Indexed: 12/14/2022]
Abstract
The vitreous body is a viscoelastic gel-like network that fills the space between the lens and the retina in the eye. With aging, the vitreous undergoes a liquefaction process in which liquid pockets form in the gel network, thereby motivating the detachment of the vitreous from the retina in a process known as posterior vitreous detachment (PVD). The PVD process may lead to the formation of floaters and even result in partial or complete loss of vision. Experiments show that the liquefaction and the PVD processes alter the mechanical properties of the vitreous. In this work, we propose a microscopically motivated model that characterizes the changes in the mechanical properties of the vitreous due to aging. To this end, we distinguish between four vitreous states: a homogeneous vitreous, a liquefied vitreous, a vitreous that undergoes partial PVD, and a vitreous with full PVD. The model predicts the time-dependent and the steady-state response of the vitreous in each of the four states. The proposed framework is validated through a comparison with various experimental findings and captures the softening of the vitreous due to aging. We illustrate the importance of the age at which the PVD process begins and of the rate of the detachment process. In addition, we introduce a quantifiable parameter that describes the stage of PVD in the eye. Lastly, we employ our model to investigate the possibility of restoring the mechanical properties of a vitreous that has undergone PVD through the addition of reinforcing fibers to the gel. This work provides insight into the consequences of the age-related changes in the microstructure of the eye and serves as a motivation for new therapeutic measures.
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Affiliation(s)
- Michal Levin
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Noy Cohen
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
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11
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Tram NK, Maxwell CJ, Swindle-Reilly KE. Macro- and Microscale Properties of the Vitreous Humor to Inform Substitute Design and Intravitreal Biotransport. Curr Eye Res 2020; 46:429-444. [PMID: 33040616 DOI: 10.1080/02713683.2020.1826977] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested in vitro, has been hypothesized to be different in vivo. Future studies should focus on testing the mechanical properties of the vitreous in situ or in vivo. In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.
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Affiliation(s)
- Nguyen K Tram
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Courtney J Maxwell
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology & Visual Science, The Ohio State University, Columbus, OH, USA
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12
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Rangchian A, Hubschman JP, Kavehpour HP. Time dependent degradation of vitreous gel under enzymatic reaction: Polymeric network role in fluid properties. J Biomech 2020; 109:109921. [DOI: 10.1016/j.jbiomech.2020.109921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 02/06/2023]
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13
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Viruni N, Zhang AY, Wang X, Handa JT, Liu TYA. Quantitative Ocular Ultrasound Findings in Microbial Keratitis-Associated Endophthalmitis. Ophthalmol Retina 2020; 4:560-567. [PMID: 32147489 DOI: 10.1016/j.oret.2020.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
PURPOSE To assess how ocular ultrasound findings correlate with clinical parameters of patients with infectious keratitis and concern for endophthalmitis and to evaluate the usefulness of ultrasound in managing these patients. DESIGN Retrospective study. PARTICIPANTS Seventy-three eyes of 73 patients with microbial keratitis who underwent ultrasound to evaluate for endophthalmitis were included. METHODS Ultrasound images were graded in a masked fashion independently by 2 retina specialists. The degree of vitreous opacities, defined as the largest area within the vitreous cavity occupied by opacities on any single image, were categorized as less than 10%, 10% to less than 50%, 50% to 90%, and more than 90%. The diagnosis of endophthalmitis was defined as severe intraocular inflammation that necessitated obtaining an intraocular culture sample and injection of intravitreal antimicrobials. The demographic and clinical characteristics of this patient cohort were compared. MAIN OUTCOME MEASURES Vitreous opacities measured quantitatively on ocular ultrasound. RESULTS The incidence of endophthalmitis in our patients with microbial keratitis who underwent ultrasound was 20.5%. Corneal and intraocular cultures showed positive results in 66.7% and 26.7% of endophthalmitis patients, respectively. A 4-fold increase in the likelihood of treatment for endophthalmitis was observed with increasing vitreous opacity severity (odds ratio, 3.97; confidence interval, 1.9-8.5; P < 0.0001). Endophthalmitis was associated with 50% or more vitreous opacities (P < 0.001), older age (P < 0.001), pseudophakia (P = 0.001), and hypopyon height (P < 0.001). Eye pain, eyelid edema, poor presenting visual acuity, larger corneal ulcer diameter, and causative organisms were not associated with endophthalmitis. CONCLUSIONS Patients with more severe vitreous opacities on ultrasound were more likely to be treated for endophthalmitis. Patients with microbial keratitis, who were older and pseudophakic, were prone to have more severe vitreous opacities.
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Affiliation(s)
- Narine Viruni
- Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Alice Y Zhang
- Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Xueyang Wang
- Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland
| | - James T Handa
- Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland
| | - T Y Alvin Liu
- Wilmer Eye Institute, The Johns Hopkins Hospital, Baltimore, Maryland.
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Thakur SS, Pan X, Kumarasinghe GL, Yin N, Pontré BP, Vaghefi E, Rupenthal ID. Relationship between rheological properties and transverse relaxation time (T2) of artificial and porcine vitreous humour. Exp Eye Res 2020; 194:108006. [DOI: 10.1016/j.exer.2020.108006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 12/20/2022]
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Thakur SS, Shenoy SK, Suk JS, Hanes JS, Rupenthal ID. Validation of hyaluronic acid-agar-based hydrogels as vitreous humor mimetics for in vitro drug and particle migration evaluations. Eur J Pharm Biopharm 2020; 148:118-125. [PMID: 31981693 DOI: 10.1016/j.ejpb.2020.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/16/2020] [Accepted: 01/19/2020] [Indexed: 12/26/2022]
Abstract
Artificial vitreous humor holds immense potential for use in in vitro intravitreal drug delivery assays. In this study, we investigated rheological properties and drug or nanoparticle migration in hyaluronic acid (HA) - agar based hydrogels and compared these characteristics with bovine vitreous humor. Gel compositions identified in literature containing HA (0.7-5.0 mg/ml) and agar (0.95-4.0 mg/ml) were classified as either high (VH), medium (VM) or low (VL) polymer load. Viscoelastic behavior was evaluated using oscillatory rheology, and migration of differently sized and charged polystyrene nanoparticles (NPs) through the different gels was determined via multiple particle tracking. Comparable rheological behaviour was observed between VL and bovine vitreous. Tracking evaluations revealed that increasing particle size and gel viscosity slowed NP migration. Additionally, 100 nm anionic NPs migrated slower than neutral NPs in VL and VM, while cationic NPs were immobile in all gels. Finally, distribution and clearance of sodium fluorescein was used to model drug mobility through the gels using a custom-built eye model. Flow and angular movement only influenced drug migration in VL and VM, but not VH. Finally, VL and VM demonstrated to have the most similar sodium fluorescein clearance to that of bovine vitreous humor. Together, these evaluations demonstrate that low viscosity HA-agar gels can be used to approximate nanoparticle and drug migration through biological vitreous humor.
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Affiliation(s)
- Sachin S Thakur
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Siddharth K Shenoy
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Jung Soo Suk
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Justin S Hanes
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Ankamah E, Sebag J, Ng E, Nolan JM. Vitreous Antioxidants, Degeneration, and Vitreo-Retinopathy: Exploring the Links. Antioxidants (Basel) 2019; 9:antiox9010007. [PMID: 31861871 PMCID: PMC7022282 DOI: 10.3390/antiox9010007] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/05/2019] [Accepted: 12/16/2019] [Indexed: 02/06/2023] Open
Abstract
The transparent vitreous body, which occupies about 80% of the eye’s volume, is laden with numerous enzymatic and non-enzymatic antioxidants that could protect the eye from oxidative stress and disease. Aging is associated with degeneration of vitreous structure as well as a reduction in its antioxidant capacity. A growing body of evidence suggests these age-related changes may be the precursor of numerous oxidative stress-induced vitreo-retinopathies, including vision degrading myodesopsia, the clinically significant entoptic phenomena that can result from advanced vitreous degeneration. Adequate intravitreal antioxidant levels may be protective against vitreous degeneration, possibly preventing and even improving vision degrading myodesopsia as well as mitigating various other vitreo-retinopathies. The present article is, therefore, a review of the different antioxidant molecules within vitreous and the inter-relationships between vitreous antioxidant capacity and degeneration.
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Affiliation(s)
- Emmanuel Ankamah
- Nutrition Research Centre Ireland, School of Health Science, Carriganore House, Waterford Institute of Technology, West Campus, Co., X91 K236 Waterford, Ireland;
- Institute of Eye Surgery, UPMC Whitfield, Buttlerstown, Co., X91 DH9W Waterford, Ireland
- Correspondence: (E.A.); (J.M.N.)
| | - J. Sebag
- VMR Consulting Inc., Huntington Beach, CA 92647, USA;
| | - Eugene Ng
- Nutrition Research Centre Ireland, School of Health Science, Carriganore House, Waterford Institute of Technology, West Campus, Co., X91 K236 Waterford, Ireland;
- Institute of Eye Surgery, UPMC Whitfield, Buttlerstown, Co., X91 DH9W Waterford, Ireland
| | - John M. Nolan
- Nutrition Research Centre Ireland, School of Health Science, Carriganore House, Waterford Institute of Technology, West Campus, Co., X91 K236 Waterford, Ireland;
- Correspondence: (E.A.); (J.M.N.)
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Subrizi A, del Amo EM, Korzhikov-Vlakh V, Tennikova T, Ruponen M, Urtti A. Design principles of ocular drug delivery systems: importance of drug payload, release rate, and material properties. Drug Discov Today 2019; 24:1446-1457. [DOI: 10.1016/j.drudis.2019.02.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/10/2019] [Accepted: 02/01/2019] [Indexed: 12/26/2022]
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18
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Schulz A, Wahl S, Rickmann A, Ludwig J, Stanzel BV, von Briesen H, Szurman P. Age-Related Loss of Human Vitreal Viscoelasticity. Transl Vis Sci Technol 2019; 8:56. [PMID: 31293811 PMCID: PMC6602139 DOI: 10.1167/tvst.8.3.56] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/06/2019] [Indexed: 02/02/2023] Open
Abstract
Purpose To determine the viscoelasticity of human vitreous bodies and its changes with age in order to benefit the understanding and therapy of vitreoretinal diseases. Methods In a postmortem study, 190 human vitreous bodies were extracted from 33- to 92-year-old donors, analyzed with regard to their viscoelastic properties via dynamic mechanical analyses, and compared with bovine and porcine vitreous. Postmortem intervals and donor-related parameters were examined as potential parameters influencing vitreous viscoelasticity. Dynamic moduli of different hyaluronic acid (HA) solutions as well as human vitreous treated with HA injections were determined by frequency sweep tests. Results With age the viscoelasticity of human vitreous bodies decreased significantly and independently of postmortem intervals, diabetes, and the donor's sex. The storage modulus G′ and loss modulus G″ correlated strongly with the donor's age with r = −0.789 and r = −0.764, respectively. Bovine and porcine vitreous bodies exhibited dynamic moduli comparable only to the viscoelastic properties of aged human vitreous and are thus limited models for the simulation of the human vitreous. The viscoelasticity of aged human vitreous bodies was found to be increased after intravitreal injections of highly concentrated HA. Conclusions The present postmortem study is the first to show a significant age-related reduction in the viscoelasticity of entire human vitreous bodies. Highly concentrated HA injections may serve as a possible therapeutic approach for restoring the viscoelasticity of aged vitreous bodies. Translational Relevance These findings improve the understanding and therapy of the vitreous liquefaction with age and the associated vitreoretinal diseases.
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Affiliation(s)
- André Schulz
- Fraunhofer Institute for Biomedical Engineering, Sulzbach, Germany
| | - Silke Wahl
- Knappschaft Eye Clinic Sulzbach, Sulzbach, Germany
| | | | | | - Boris V Stanzel
- Fraunhofer Institute for Biomedical Engineering, Sulzbach, Germany.,Knappschaft Eye Clinic Sulzbach, Sulzbach, Germany
| | | | - Peter Szurman
- Knappschaft Eye Clinic Sulzbach, Sulzbach, Germany.,Centre for Ophthalmology, University Eye Hospital Tuebingen, Tuebingen, Germany
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