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Ran RJ, Wang T, Tao MY, Gou YQ, Zhang M. A novel approach for 25-gauge transconjunctival sutureless vitrectomy to evaluate vitreous substitutes in rabbits. Int J Ophthalmol 2023; 16:1568-1573. [PMID: 37854378 PMCID: PMC10559039 DOI: 10.18240/ijo.2023.10.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/09/2023] [Indexed: 10/20/2023] Open
Abstract
AIM To improve the standard three-port vitrectomy for establishing and evaluating an endotamponade model in rabbits. METHODS Three ports were prepared near the third eyelid of rabbits, and the infusion port was placed at the inferior nasal quadrant with the inserted cannula linking with a self-designed handheld rigid infusion catheter. All right eyes of rabbits underwent a modified 25-gauge vitrectomy and were subsequently filled with balanced salt solution, silicone oil, and eight-arm polyethylene glycols (8-arm PEGs) hydrogel separately for comparison. Ophthalmic examinations were performed regularly to record the changes after the surgery. RESULTS Successful vitrectomy was achieved among 44 chinchilla rabbits. The mean operation time was 4.51±1.25min. Four eyes (9.1%) presented limited lens touch and two eyes (4.5%) showed retinal touch during surgery. Incision leakage was found in three eyes (6.8%) after surgery. There was no endophthalmitis, hemorrhage, or retinal detachment during the observation period and ophthalmic examinations after the implantation of vitreous substitutes. CONCLUSION The modified technique of the standard vitrectomy applied in the endotamponade model in rabbits shows excellent safety and practicality.
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Affiliation(s)
- Rui-Jin Ran
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
- Department of Ophthalmology, Minda Hospital of Hubei Minzu University, Enshi 445000, Hubei Province, China
| | - Ting Wang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Meng-Ying Tao
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Yue-Qin Gou
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Ming Zhang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
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2
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Naik K, Du Toit LC, Ally N, Choonara YE. Advances in Polysaccharide- and Synthetic Polymer-Based Vitreous Substitutes. Pharmaceutics 2023; 15:pharmaceutics15020566. [PMID: 36839888 PMCID: PMC9961338 DOI: 10.3390/pharmaceutics15020566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
The vitreous humour is a gel-like structure that composes the majority of each eye. It functions to provide passage of light, be a viscoelastic dampener, and hold the retina in place. Vitreous liquefaction causes retinal detachment and retinal tears requiring pars plana vitrectomy for vitreous substitution. An ideal vitreous substitute should display similar mechanical, chemical, and rheological properties to the natural vitreous. Currently used vitreous substitutes such as silicone oil, perfluorocarbon liquids, and gases cannot be used long-term due to adverse effects such as poor retention time, cytotoxicity, and cataract formation. Long-term, experimental vitreous substitutes composed of natural, modified and synthetic polymers are currently being studied. This review discusses current long- and short-term vitreous substitutes and the disadvantages of these that have highlighted the need for an ideal vitreous substitute. The review subsequently focuses specifically on currently used polysaccharide- and synthetic polymer-based vitreous substitutes, which may be modified or functionalised, or employed as the derivative, and discusses experimental vitreous substitutes in these classes. The advantages and challenges associated with the use of polymeric substitutes are discussed. Innovative approaches to vitreous substitution, namely a novel foldable capsular vitreous body, are presented, as well as future perspectives related to the advancement of this field.
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Affiliation(s)
- Kruti Naik
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Lisa C. Du Toit
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Naseer Ally
- Division of Ophthalmology, Department of Neurosciences, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Yahya E. Choonara
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
- Correspondence: ; Tel.: +27-11-717-2052
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3
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Valentín‐Bravo FJ, García‐Onrubia L, Andrés‐Iglesias C, Valentín‐Bravo E, Martín‐Vallejo J, Pastor JC, Usategui‐Martín R, Pastor‐Idoate S. Complications associated with the use of silicone oil in vitreoretinal surgery: A systemic review and meta-analysis. Acta Ophthalmol 2022; 100:e864-e880. [PMID: 34846097 DOI: 10.1111/aos.15055] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/24/2021] [Accepted: 10/25/2021] [Indexed: 12/18/2022]
Abstract
Silicone oil (SO) still represents the main choice for long-term intraocular tamponade in complicated vitreoretinal surgery. This review compared the complications associated with the use of SO and other vitreous substitutes after pars plana vitrectomy in patients with different underlying diseases. Meta-analysis was conducted in accordance with PRISMA guidelines. We retrieved randomized clinical trials (RCTs), retrospective case-control and cohort studies evaluating the risk of using SO, published between 1994 and 2020, conducting a computer-based search of the following databases: PubMed, Web of Science, Scopus and Embase. Primary outcome was the rate of complications such as intraocular hypertension, retinal re-detachment, unexpected vision loss or hypotony. Secondary outcome was to compare the rate of adverse events of different SO viscosities, especially emulsification. Forty-three articles were included. There were significant differences in intraocular hypertension (p = 0.0002, OR = 1.66; 95% CI = 1.27-2.18) and the rate of retinal re-detachment (p < 0.0009, OR = 0.65; 95% CI = 0.50-0.64) between SO and other agents, including placebo. However, there were no differences in other complication rates. Silicone oil (SO)-emulsification rate was non-significantly higher in low than high SO viscosity, and results from other complications were comparable in both groups. The high quality of most of the studies included in this study is noteworthy, which provides some certainty to the conclusions. Among them is the high variability of the SO residence time. The fact that ocular hypertension and not hypotension is related to SO use. A clear relationship is not found for the so-called unexplained vision loss, which affects a significant percentage of eyes. Re-detachment cases are less if SO is used and that surprisingly there does not seem to be a relationship in the percentage of emulsification between the low- and high-viscosity silicones. All these data warrant more standardized prospective studies.
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Affiliation(s)
- Fco. Javier Valentín‐Bravo
- Department of Ophthalmology University Clinical Hospital of Valladolid Valladolid Spain
- Institute of Applied Ophthalmobiology (IOBA) University of Valladolid Valladolid Spain
| | - Luis García‐Onrubia
- Department of Ophthalmology University Clinical Hospital of Valladolid Valladolid Spain
| | | | | | - Javier Martín‐Vallejo
- Department of Statistics. Medical School University of Salamanca. Salamanca Biomedical Research Institute (IBSAL) Salamanca Spain
| | - José Carlos Pastor
- Department of Ophthalmology University Clinical Hospital of Valladolid Valladolid Spain
- Institute of Applied Ophthalmobiology (IOBA) University of Valladolid Valladolid Spain
- Medical School University of Valladolid Valladolid Spain
- Cooperative Network for Research in Ophthalmology (Oftared) Carlos III National Institute of Health, ISCIII Madrid Spain
| | - Ricardo Usategui‐Martín
- Institute of Applied Ophthalmobiology (IOBA) University of Valladolid Valladolid Spain
- Medical School University of Valladolid Valladolid Spain
- Cooperative Network for Research in Ophthalmology (Oftared) Carlos III National Institute of Health, ISCIII Madrid Spain
| | - Salvador Pastor‐Idoate
- Department of Ophthalmology University Clinical Hospital of Valladolid Valladolid Spain
- Institute of Applied Ophthalmobiology (IOBA) University of Valladolid Valladolid Spain
- Medical School University of Valladolid Valladolid Spain
- Cooperative Network for Research in Ophthalmology (Oftared) Carlos III National Institute of Health, ISCIII Madrid Spain
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Hurst J, Rickmann A, Heider N, Hohenadl C, Reither C, Schatz A, Schnichels S, Januschowski K, Spitzer MS. Long-Term Biocompatibility of a Highly Viscously Thiol-Modified Cross-Linked Hyaluronate as a Novel Vitreous Body Substitute. Front Pharmacol 2022; 13:817353. [PMID: 35308238 PMCID: PMC8924550 DOI: 10.3389/fphar.2022.817353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/17/2022] [Indexed: 01/23/2023] Open
Abstract
Purpose: In surgical ophthalmology, the treatment of complicated retinal and vitreous diseases is one of the central challenges. For this purpose, the vitreous body is removed as part of the standard therapy and replaced by a temporary tamponade to stabilize the position of the retina. Since the tamponading properties of previous materials such as silicone oils, gases, or semi-fluorinated alkanes are a combination of their surface tension and their buoyancy vector, they cannot completely fill the vitreous cavity. The aim of this work was to test in vivo a novel vitreous body substitute (ViBos strong) based on cross-linked hyaluronic acid for its compatibility. Methods: A pars plana vitrectomy with posterior vitreous detachment was performed in the right eye of 18 pigmented rabbits, with subsequent injection of ViBos strong. Follow-up examination included slit-lamp examination, funduscopy, intraocular pressure measurements (IOP), optical coherence tomography (OCT), and electroretinogram (ERG) measurements. The rabbits were sacrificed at three different time points (1, 3, and 6 months; each 6 animals) and examined macroscopically and prepared for histological examination (HE staining) and immunohistochemistry (Brn3a and glial fibrillary acidic protein (GFAP)). Results: ViBos strong demonstrated good intraoperative handling and remained stable for at least 1 month and degraded slowly over 6 months. IOP was within clinical acceptable values at all follow-up examinations. Retinal function was well preserved after instillation of the hydrogel and comparable to the untreated eye after 6 months in OCT, ERG, and histological examinations. An increase in the GFAP expression was found in the surgery eyes, with a peak in the 3-month group. The Brn3a expression was not significantly affected by vitrectomy with ViBos strong. Conclusion: Highly viscously thiol-modified cross-linked hyaluronate showed a good biocompatibility in rabbit eyes over 6 months after vitrectomy, making it a promising potential as a vitreous substitute.
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Affiliation(s)
- Jose Hurst
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | | | - Nele Heider
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | | | | | - Andreas Schatz
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - Sven Schnichels
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - Kai Januschowski
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany.,Mount St. Peter Eye Clinic Trier, Trier, Germany
| | - Martin S Spitzer
- Centre of Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany.,Department of Ophthalmology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
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5
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Auel T, Großmann L, Schulig L, Weitschies W, Seidlitz A. The EyeFlowCell: Development of a 3D-Printed Dissolution Test Setup for Intravitreal Dosage Forms. Pharmaceutics 2021; 13:pharmaceutics13091394. [PMID: 34575470 PMCID: PMC8464925 DOI: 10.3390/pharmaceutics13091394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 08/31/2021] [Indexed: 12/24/2022] Open
Abstract
An in vitro dissolution model, the so-called EyeFlowCell (EFC), was developed to test intravitreal dosage forms, simulating parameters such as the gel-like consistency of the vitreous body. The developed model consists of a stereolithography 3D-printed flow-through cell with a polyacrylamide (PAA) gel as its core. This gel needed to be coated with an agarose sheath because of its low viscosity. Drug release from hydroxypropyl methylcellulose-based implants containing either triamcinolone acetonide or fluorescein sodium was studied in the EFC using a schematic eye movement by the EyeMovementSystem (EyeMoS). For comparison, studies were performed in USP apparatus 4 and USP apparatus 7. Significantly slower drug release was observed in the PAA gel for both model drugs compared with the compendial methods. Drug release from fluorescein sodium-containing model implants was completed after 40 min in USP apparatus 4, whereas drug release in the gel-based EFC lasted 72 h. Drug release from triamcinolone acetonide-containing model implants was completed after 35 min in USP apparatus 4 and after 150 min in USP apparatus 7, whereas this was delayed until 96 h in the EFC. These results suggest that compendial release methods may overestimate the drug release rate in the human vitreous body. Using a gel-based in vitro release system such as the EFC may better predict drug release.
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Affiliation(s)
- Tobias Auel
- Center of Drug Absorption and Transport, Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (T.A.); (L.G.); (W.W.)
| | - Linus Großmann
- Center of Drug Absorption and Transport, Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (T.A.); (L.G.); (W.W.)
| | - Lukas Schulig
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany;
| | - Werner Weitschies
- Center of Drug Absorption and Transport, Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (T.A.); (L.G.); (W.W.)
| | - Anne Seidlitz
- Center of Drug Absorption and Transport, Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany; (T.A.); (L.G.); (W.W.)
- Correspondence: ; Tel.: +49-3834-420-4898
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6
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Wang T, Ran R, Ma Y, Zhang M. Polymeric hydrogel as a vitreous substitute: current research, challenges, and future directions. Biomed Mater 2021; 16. [PMID: 34038870 DOI: 10.1088/1748-605x/ac058e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/26/2021] [Indexed: 02/08/2023]
Abstract
Vitreoretinal surgery is an essential approach to treat proliferative diabetic vitreopathy, retinal detachment, retinal tear, ocular trauma, and macular holes. The removal of the natural vitreous and the replacement with substitutes are critical steps for retina reattachment. Vitreous substitutes including silicone oil (SiO), air, sulfur hexafluoride (SF6), and perfluoropropane (C3F8), have been widely applied in clinical practice. However, these substitutes are reported to cause complications such as emulsification, high intraocular pressure, and lens opacification. Polymeric hydrogels are a kind of material with favorable physical, mechanical properties, and adaptable biocompatibility, thus being highly expected to be ideal vitreous substitutes. Despite years of research, very few polymeric hydrogels can be applied practically in the vitreous cavity. In this review, we focus on the development of polymeric natural-based hydrogels and synthetic hydrogels. Particularly, we pay attention to recent advances in the novel stimuli-response and self-assembly supramolecular hydrogels. Characterized by easy injectability and long residence time, this kind of hydrogel becomes the potentially promising candidates for ideal vitreous substitutes. Finally, we evaluate the current challenges and provide the future directions of vitreous substitutes.
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Affiliation(s)
- Ting Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China.,West China School of Medicine, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Ruijin Ran
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China.,Minda Hospital of Hubei Minzu University, Enshi, People's Republic of China
| | - Yan Ma
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, People's Republic of China
| | - Ming Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
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7
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Zeng B, Wang Q, Sui G, Wang M, Xie W, Fu J. Foldable capsular vitreous body implantation for treatment of traumatic retinal detachment: two case reports. J Int Med Res 2021; 49:300060521990257. [PMID: 33563057 PMCID: PMC7879493 DOI: 10.1177/0300060521990257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Retinal detachment caused by severe ocular trauma is a type of refractory vitreoretinal disease. Current treatment methods include vitrectomy combined with silicone oil tamponade. However, long-term use of silicone oil tamponade has various complications, including a risk of silicone oil dependence that eventually leads to eyeball atrophy and enucleation. Foldable capsular vitreous bodies (FCVBs) offer a good solution for these problems. However, FCVBs have not been used in large-scale clinical applications and few cases have been reported in the published literature. The main use of FCVBs, based on current evidence, is in the treatment of the relatively few (but important) patients whose eyes have no visual potential; the aim of treatment in these patients is globe preservation, rather than restoration of vision. Here, we describe two patients who underwent FCVB implantation. The findings in these patients indicated that FCVBs can effectively support the vitreous cavity and detached retina. FCVB implantation may thus offer a safe and effective method for treatment of severe retinal detachment, avoiding the inconvenience caused by silicone oil dependence and enucleation. To confirm its long-term usefulness in clinical applications, many additional case reports are needed.
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Affiliation(s)
- Baihui Zeng
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Qian Wang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Guiqin Sui
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Mingxuan Wang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Wei Xie
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Jinling Fu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
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8
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Thacker M, Tseng CL, Lin FH. Substitutes and Colloidal System for Vitreous Replacement and Drug Delivery: Recent Progress and Future Prospective. Polymers (Basel) 2020; 13:E121. [PMID: 33396863 PMCID: PMC7796247 DOI: 10.3390/polym13010121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 01/10/2023] Open
Abstract
Vitreoretinal surgeries for ocular diseases such as complicated retinal detachment, diabetic retinopathy, macular holes and ocular trauma has led to the development of various tamponades over the years in search for an ideal vitreous substitute. Current clinically used tamponade agents such as air, perfluorocarbons, silicone oil and expansile gases serve only as a short-term solution and harbors various disadvantages. However, an ideal long-term substitute is yet to be discovered and recent research emphasizes on the potential of polymeric hydrogels as an ideal vitreous substitute. This review highlights the recent progress in the field of vitreous substitution. Suitability and adverse effects of various tamponade agents in present day clinical use and biomaterials in the experimental phase have been outlined and discussed. In addition, we introduced the anatomy and functions of the native vitreous body and the pathological conditions which require vitreous replacement.
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Affiliation(s)
- Minal Thacker
- Graduate Institute of Biomedical Engineering, National Taiwan University, Daan District, Taipei 10051, Taiwan;
| | - Ching-Li Tseng
- Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Feng-Huei Lin
- Graduate Institute of Biomedical Engineering, National Taiwan University, Daan District, Taipei 10051, Taiwan;
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli County 35053, Taiwan
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9
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Schulz A, Rickmann A, Wahl S, Germann A, Stanzel BV, Januschowski K, Szurman P. Alginate- and Hyaluronic Acid-Based Hydrogels as Vitreous Substitutes: An In Vitro Evaluation. Transl Vis Sci Technol 2020; 9:34. [PMID: 33384888 PMCID: PMC7757634 DOI: 10.1167/tvst.9.13.34] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/15/2020] [Indexed: 01/09/2023] Open
Abstract
Purpose To study alginate- and hyaluronic acid–based hydrogels in vitro as vitreous substitutes. Methods Biopolymeric hydrogels based on high-molecular alginate (0.5% and 1.0%) and hyaluronic acid (1.0% and Healaflow) were compared with extracted human vitreous bodies and silicone oil (SIL-5000) regarding their optical properties (refractive index, transmission) and viscoelastic characteristics (storage modulus G′, loss modulus G″). The cytotoxic (metabolic activity, apoptosis) and antiproliferative profiles were determined using cultured human fibroblasts, ARPE-19, and photoreceptor cells. The hydrogel systems were applied to human fetal retinal pigment epithelial cells cultured for two months until maximum transepithelial electrical resistance (TEER) to investigate the effect of the gel matrices on tight junctions using TEER measurements and immunostainings against the tight junction protein ZO-1. Results Tested alginate- and hyaluronic acid–based hydrogels resembled the natural refractive index of human vitreous bodies (1.3356–1.3360) in contrast to SIL-5000 (1.4034) and showed high optical transparency (>90%) within the visible light region. The biopolymeric hydrogels exhibited viscoelastic properties similar to juvenile vitreous bodies with G′>G″ adjustable via different gelation times, contrary to SIL-5000 (G′<G″). The metabolic activity, apoptosis and tight junctions of all tested ocular cells were unaffected by the alginate- and hyaluronic acid–based vitreous substitutes. Conclusions The present in vitro study demonstrates good optical, viscoelastic, and biocompatible properties of alginate- and hyaluronic acid–based hydrogels required for their use as vitreous substitutes. Translational Relevance Biopolymer-based hydrogels represent a promising vitreous replacement strategy to treat vitreoretinal diseases.
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Affiliation(s)
- André Schulz
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Annekatrin Rickmann
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Silke Wahl
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Anja Germann
- Fraunhofer Institute for Biomedical Engineering, Sulzbach, Germany
| | - Boris Viktor Stanzel
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany.,Fraunhofer Institute for Biomedical Engineering, Sulzbach, Germany
| | - Kai Januschowski
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany.,Centre for Ophthalmology, University Eye Hospital Tuebingen, Tuebingen, Germany
| | - Peter Szurman
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany.,Klaus Heimann Eye Research Institute, Sulzbach, Germany.,Centre for Ophthalmology, University Eye Hospital Tuebingen, Tuebingen, Germany
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10
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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: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Tram NK, McLean RM, Swindle-Reilly KE. Glutathione Improves the Antioxidant Activity of Vitamin C in Human Lens and Retinal Epithelial Cells: Implications for Vitreous Substitutes. Curr Eye Res 2020; 46:470-481. [PMID: 32838548 DOI: 10.1080/02713683.2020.1809002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Tissues in the eye are particularly susceptible to oxidative damage due to light exposure. While vitamin C (ascorbic acid) has been noted as a vital antioxidant in the vitreous humor, its physiological concentration (1-2 mM) has been shown to be toxic to retinal and lens epithelial cells in in vitro cell culture. We have explored adding vitamin C to hydrogel vitreous substitutes as a potential therapeutic to prevent oxidative damage to intraocular tissues after vitrectomy. However, vitamin C degrades rapidly even when loaded at high concentrations, limiting its long-term effectiveness. Glutathione, another antioxidant found abundantly in the lens at concentrations of 2-10 mM, was proposed to be used in conjunction with vitamin C. METHODS Cell viability and reactive oxygen species activity of human retinal and lens epithelial cells treated with various combinations of vitamin C, glutathione, hydrogen peroxide, and a hydrogel vitreous substitute were determined using CellTiter-Glo luminescent cell viability assay and dichlorofluorescein assay, respectively. The vitamin C remaining in hydrogel vitreous substitute or glutathione-vitamin C solutions was determined using a microplate reader at 265 nm wavelength, compared against standard solutions with known concentrations. RESULTS Glutathione protected the lens and retinal cells from the negative effect of vitamin C on cell viability and prolonged the antioxidant effect of vitamin C in vitro. While the detected reading of pure vitamin C solution decreased rapidly from 100% to 10% by 3 days, glutathione provided a significant extension to vitamin C stability, with 70% remaining after 14 days when the glutathione was used at physiological concentrations found in the lens (2-10 mM). CONCLUSIONS These results indicate glutathione might be an effective addition to vitamin C in intraocular implants, including potential vitreous substitutes, and warrants additional studies on the effectiveness of the vitamin C - glutathione combination in preventing oxidative stress post-vitrectomy.
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Affiliation(s)
- Nguyen K Tram
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Rayna M McLean
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Ophthalmology & Visual Science, The Ohio State University, Columbus, Ohio, USA
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Liang J, Struckhoff JJ, Du H, Hamilton PD, Ravi N. Synthesis and characterization of in situ forming anionic hydrogel as vitreous substitutes. J Biomed Mater Res B Appl Biomater 2017; 105:977-988. [PMID: 26873608 PMCID: PMC5654599 DOI: 10.1002/jbm.b.33632] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/14/2015] [Accepted: 01/16/2016] [Indexed: 02/06/2023]
Abstract
The natural vitreous is a biological hydrogel consisting primarily of a collagen and anionic hyaluronate. It is surgically removed in many ocular diseases and replaced with fluids, gases, or silicone oils. We have been interested in developing synthetic hydrogels as vitreous substitutes. In this study, we combined the stiffness and hydrophobicity of polymethacrylamide (PMAM) and the anionic nature of polymethacrylate (PMAA) to make copolymers that would mimic the natural vitreous. We used bis-methacryloyl cystamine (BMAC) to introduce thiol groups for reversible crosslink. The Mn of copolymers ranged from ∼100 k to ∼200 k Da (polydisperisty index of 1.47-2.63) and their composition as determined by titration, 1 H NMR and disulfide test were close to the feed ratio. The reactivities of monomers were as follows: MAM > MAA ∼ BMAC. Copolymers with higher MAA contents gelled faster, swelled more, and had higher storage modulus (1.5 to 100 Pa) comparable to that of the natural vitreous. We evaluated the biocompatibility of copolymers by electric cell-substrate impedance sensing (ECIS) using human retinal pigment epithelial cells, primary porcine retinal pigmented epithelial cells, human microvascular endothelial cells adult dermis, and a fibroblast line 3T3. The biocompatibility decreases as the content of BMAC increases. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 977-988, 2017.
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Affiliation(s)
- Jue Liang
- Department of Ophthalmology and Visual Sciences, WA University School of Medicine, Saint Louis, Missouri
| | - Jessica J Struckhoff
- Department of Ophthalmology and Visual Sciences, WA University School of Medicine, Saint Louis, Missouri
| | - Hongwei Du
- Department of Ophthalmology and Visual Sciences, WA University School of Medicine, Saint Louis, Missouri
| | - Paul D Hamilton
- Department of Ophthalmology and Visual Sciences, WA University School of Medicine, Saint Louis, Missouri
| | - Nathan Ravi
- Department of Ophthalmology and Visual Sciences, WA University School of Medicine, Saint Louis, Missouri
- Department of Energy, Environmental and Chemical Engineering, WA University in St. Louis, Saint Louis, Missouri
- Department of Research, Veterans Affairs Medical Center, Saint Louis, Missouri
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Lin X, Sun X, Wang Z, Jiang Z, Liu Y, Wang P, Gao Q. Three-Year Efficacy and Safety of a Silicone Oil-Filled Foldable-Capsular-Vitreous-Body in Three Cases of Severe Retinal Detachment. Transl Vis Sci Technol 2016; 5:2. [PMID: 26855843 PMCID: PMC4736667 DOI: 10.1167/tvst.5.1.2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 10/12/2015] [Indexed: 11/30/2022] Open
Abstract
Purpose We previously designed a novel foldable capsular vitreous body (FCVB) to treat severe retinal detachment and evaluated its performance in a 1-year follow up study. The purpose of this study was to determine the efficacy and safety of a silicone oil (SO)-filled FCVB in a 3-year follow-up. Methods Standard three-port pars plana vitrectomy was performed, and the FCVB was triple folded and implanted in the vitreous cavity of three eyes. The SO then was injected into the capsule to support the retina. The eyes were examined using Goldmann applanation tonometry, fundus photography, optical coherence tomography (OCT), noncontact specular microscopy, and ultrasound biomicroscopy over a 3-year implantation period. Results At the 3-year follow-up, retinal reattachment was achieved in all three cases, with steady intraocular pressure. The visual acuity showed slight fluctuations, and it was slightly increased compared to baseline. Optical coherence tomography revealed decreased retinal thickness and an altered retinal structure in the implanted eyes compared to the control eyes. No keratopathy, glaucoma, SO leakage, SO emulsification, or other apparent complications occurred during the observation period. Conclusion The SO-filled FCVB was effective and safe as a vitreous substitute in three eyes over a 3-year observation period. Translational Relevance Silicone oil emulsification is a severe complication after retinal detachment surgery. On the basis of animal experiments, we investigated a new strategy and product, the FCVB, to overcome this complication. In this pilot study, FCVB limited SO emulsification and migration. This study could lay the foundation for a further multicenter clinical trial.
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Affiliation(s)
- Xiaofeng Lin
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xuyuan Sun
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zhenfang Wang
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zhaoxin Jiang
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yaqin Liu
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Peijuan Wang
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qianying Gao
- State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Abstract
The natural vitreous body has a fine structure and complex functions. The imitation of the natural vitreous body by vitreous substitutes is a challenging work for both researchers and ophthalmologists. Gases, silicone oil, heavy silicone oil and hydrogels, particularly the former two vitreous substitutes are clinically widely used with certain complications. Those, however, are not real artificial vitreous due to lack of structure and function like the natural vitreous body. This article reviews the situations, challenges, and future directions in the development of vitreous substitutes, particularly the experimental and clinical use of a new artificial foldable capsular vitreous body.
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Affiliation(s)
- Qian-Ying Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Yue Fu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Yan-Nian Hui
- Department of Ophthalmology, Xijing Hospital, the Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
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Jiang Z, Wang T, Pan B, Xie Z, Wang P, Liu Y, Gao Q. Evaluation of the levofloxacin release characters from a rabbit foldable capsular vitreous body. Int J Nanomedicine 2011; 7:1-10. [PMID: 22275817 PMCID: PMC3260945 DOI: 10.2147/ijn.s25268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Indexed: 11/23/2022] Open
Abstract
The authors have manufactured a novel rabbit foldable capsular vitreous body (FCVB). The aim of this study was to determine whether this rabbit FCVB can release levofloxacin in vitro and in vivo, and to evaluate the release characteristics. In vitro, the rabbit FCVB with levofloxacin 500 μg/mL was immersed in cups of modified Franz diffusion cells. Following this, 200 μL of liquid was aspirated at intervals from 10 minutes to 24 hours. In vivo, the FCVB with levofloxacin was implanted into the right eyes of five rabbits. After implantation, the aqueous humor was aspirated on days 1, 7, 14, 28, and 56. The levofloxacin concentrations in the cups and aqueous humor samples were detected by high-performance liquid chromatography–tandem mass spectrometry. The FCVB was observed under a scanning electron microscope. The results showed that the released levofloxacin was stabilized at 20 ng/mL at time points from 10 minutes to 24 hours in vitro. In vivo, levofloxacin concentrations in the aqueous humor were 132, 50, 39, 11, and 15 ng/mL on days 1, 7, 14, 28, and 56, respectively. In the FCVB capsules, 300 nm apertures were observed. These results suggest the rabbit FCVB released levofloxacin stably in vitro and sustainably in vivo. This study provides a novel combined approach, with the FCVB as a vitreous substitute and drug delivery system for the treatment of bacterial endophthalmitis.
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Affiliation(s)
- Zhaoxin Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
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Abstract
Modern vitreoretinal surgery is a young science. While tremendous developments have occurred in instrument design and technique since Machemer first described vitrectomy surgery in 1973[1], the application of advanced materials concepts to the development of intra-ocular compounds is a particularly exciting area of research. To date, the development of vitreous substitutes has played a significant role in enabling the dramatic and progressive improvement in surgical outcome, but perhaps no other area of research has the potential to further improve the treatment of retinal detachment and other retinal disorders. While prior research has focused solely upon the ability of a compound to re-attach the retina, future research should seek to enable the surgeon to inhibit the development of proliferative vitreoretinopathy and re-detachment, the integration of stem-cell therapies with surgical retina, long-term delivery of medications to the posterior segment, and the promotion of more rapid and complete visual rehabilitation.
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Affiliation(s)
- William Joseph Foster
- Research Professor, Department of Physics, The University of Houston, Houston, TX, and Clinical Associate Professor, Department of Ophthalmology, Weill Medical College of Cornell University at, The Methodist Hospital, Houston, TX, 617 Science & Research Building 1, Houston, TX 77204-5005
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