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Phillips JD, Hwang ES, Morgan DJ, Creveling CJ, Coats B. Structure and mechanics of the vitreoretinal interface. J Mech Behav Biomed Mater 2022; 134:105399. [PMID: 35963021 PMCID: PMC9552593 DOI: 10.1016/j.jmbbm.2022.105399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 07/17/2022] [Accepted: 07/24/2022] [Indexed: 12/24/2022]
Abstract
Vitreoretinal mechanics plays an important role in retinal trauma and many sight-threatening diseases. In age-related pathologies, such as posterior vitreous detachment and vitreomacular traction, lingering vitreoretinal adhesions can lead to macular holes, epiretinal membranes, retinal tears and detachment. In age-related macular degeneration, vitreoretinal traction has been implicated in the acceleration of the disease due to the stimulation of vascular growth factors. Despite this strong mechanobiological influence on trauma and disease in the eye, fundamental understanding of the mechanics at the vitreoretinal interface is limited. Clarification of adhesion mechanisms and the role of vitreoretinal mechanics in healthy eyes and disease is necessary to develop innovative treatments for these pathologies. In this review, we evaluate the existing literature on the structure and function of the vitreoretinal interface to gain insight into age- and region-dependent mechanisms of vitreoretinal adhesion. We explore the role of vitreoretinal adhesion in ocular pathologies to identify knowledge gaps and future research areas. Finally, we recommend future mechanics-based studies to address the critical needs in the field, increase fundamental understanding of vitreoretinal mechanisms and disease, and inform disease treatments.
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Affiliation(s)
- Joseph D Phillips
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Eileen S Hwang
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | - Denise J Morgan
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | | | - Brittany Coats
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States.
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Mohaček-Grošev V, Brljafa S, Škrabić M, Marić I, Blažek Bregović V, Amendola V, Ropret P, Kvaček Blažević A. Glucosamine to gold nanoparticles binding studied using Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 264:120326. [PMID: 34481250 DOI: 10.1016/j.saa.2021.120326] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/10/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
The binding of glucosamine to gold in water solutions of glucosamine hydrochloride mixed with clean colloidal gold nanoparticles obtained by laser ablation in liquid was studied using surface-enhanced Raman scattering (SERS), dynamic light scattering (DLS) and UV-VIS spectroscopy. The purpose of this study was to establish whether the binding of charged aminogroup to gold nanoparticles (AuNPs) is taking place, and if it does, how can it be identified by means of SERS. The average size of dried gold nanoparticles was (20 ± 4) nm determined by averaging the sizes observed in transmission electron microscopy micrographs, which is smaller than the average size of gold nanoparticles in water solution as determined by DLS: (52 ± 2) nm. Upon adding the glucosamine solutions to gold colloid, average hydrodynamic diameter of ions was slightly larger for 0.1 mM glucosamine solution (55 ± 2 nm), while it increased to (105 ± 22) nm in the case of 1 mM solution, and was (398 ± 54) nm when 10 mM glucosamine solution was added. Most prominent Raman bands observed both for 0.1 mM and 1 mM glucosamine solutions were located at 1165 cm-1, 1532 and 1586 cm-1 and assigned to C-N coupled with C-C stretching, and C-NH3+ deformation angles bending. In SERS spectrum of 1 mM GlcN+ solution, two strong bands at 999 and 1075 cm-1 were found and attributed to C-Oring stretching coupled with C-NH3+ bending (999 cm-1) and to dominantly C-O stretching vibration. The differences in SERS spectra are attributed to different number of glucosamine molecules that attach to gold nanoparticles and their orientation with respect to the metal particle surface, partly due to presence of beta anomers protonated at anomeric oxygen position. The assignment of glucosamine bands was further corroborated by comparison with vibrational spectra of alpha and beta glucose and of polycrystalline powder of glucosamine hydrochloride. For all three substances comprehensive calculation of vibrational density of states was conducted using density functional theory. Benchmark bands for polycrystalline glucose anomers distinction are 846 and 915 cm-1 for alpha glucose, and 902 cm-1 for beta glucose. However, the bands observed in SERS spectra of 0.1 mM glucosamine solution at 831, 899, and 946 cm-1 or in 1 mM solution at 934 cm-1 cannot be easily identified as belonging either to alpha or beta glucosamine anomer, due to complexity of atomic motions involved. The identification of vibrational bands associated with -CNH3+ group will aid SERS studies on amino acids, especially in cases when several atomic groups could possibly bind to AuNPs.
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Affiliation(s)
- Vlasta Mohaček-Grošev
- Center of Excellence for Advanced Materials and Sensing Devices, Research Unit New Functional Materials, Ruđer Bošković Institute, Bijeničkacesta 54, 10000 Zagreb, Croatia.
| | - Sandro Brljafa
- Osnovna škola Antuna Gustava Matoša, Albrechtova bb, 10000 Zagreb, Croatia
| | - Marko Škrabić
- Department of Physics and Biophysics, School of Medicine, University of Zagreb, Šalata 3b, 10000 Zagreb, Croatia
| | - Ivan Marić
- Radiation Chemistry and Dosimetry Laboratory, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Vesna Blažek Bregović
- Laboratory for Optics and Optical Thin Films, Division of Materials Physics, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Vincenzo Amendola
- Department of Chemical Sciences, University of Padova, Padova I -35131, Italy
| | - Polona Ropret
- Institute for the Protection of Cultural Heritage of Slovenia, Research Institute, Poljanska cesta 40, 1000 Ljubljana, Slovenia
| | - Anita Kvaček Blažević
- Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, Kneza Trpimira 2b, 31000 Osijek, Croatia
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Albabtain B, Mura M, Schatz P, Alsulaiman SM, Alsakran WA, Semidey VA. Comparison of Posterior Hyaloid Assessment Using Preoperative Optical Coherence Tomography and Intraoperative Triamcinolone Acetonide Staining During Vitrectomy. Clin Ophthalmol 2021; 15:3939-3945. [PMID: 34616138 PMCID: PMC8488048 DOI: 10.2147/opth.s331700] [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: 07/30/2021] [Accepted: 09/16/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose To compare the specificity of diagnosing posterior vitreous detachment (PVD) using preoperative optical coherence tomography (OCT) versus intraoperative triamcinolone acetonide (TA) staining in patients undergoing vitrectomy. Patients and Methods This retrospective cohort study included patients undergoing pars plana vitrectomy for diverse retinal pathologies. Intraoperatively, surgeons evaluated the posterior hyaloid status with TA staining and compared it with preoperative OCT findings. Results One hundred six patients underwent intraoperative assessments of posterior hyaloid status, with 72% (76/106) of the eyes showing positive staining. Sixty-two patients had also undergone preoperative OCT. Of the patients diagnosed with PVD on preoperative OCT, 50% (15/30) showed positive TA staining intraoperatively. The sensitivity of preoperative OCT assessment was 83.3%, and its specificity was 65.9%. Conclusion Preoperative OCT imaging is associated with lower sensitivity and specificity for diagnosing PVD when compared to intraoperative TA staining.
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Affiliation(s)
- Budoor Albabtain
- Research Department, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Department of Ophthalmology, Prince Sultan Medical Military City, Riyadh, Saudi Arabia
| | - Marco Mura
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | - Patrik Schatz
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Department of Ophthalmology, Clinical Sciences, Skane County University Hospital, Lund University, Lund, Sweden
| | | | - Wael A Alsakran
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Valmore A Semidey
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
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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: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [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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Recurrent Vitreomacular Traction in a Patient Treated with Ocriplasmin: A Case Report. Ophthalmol Ther 2020; 10:187-192. [PMID: 33108639 PMCID: PMC7886937 DOI: 10.1007/s40123-020-00316-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/15/2020] [Indexed: 11/01/2022] Open
Abstract
INTRODUCTION To describe a case of recurrent vitreomacular traction and macular edema that appeared both before and after the intravitreal injection of ocriplasmin. CASE REPORT An 82-year-old monocular man presented with metamorphopsia and reduced vision of 1-week duration. The patient's general medical history was unremarkable. His ophthalmic history was significant for severe ocular trauma in the right eye in childhood that caused phthisis. The left eye had undergone uncomplicated phacoemulsification 3 months earlier and the 1-month postoperative best corrected visual acuity (BCVA) was logarithmic mean angle of resolution (logMAR) 0.0. There was no history of other ocular conditions. At presentation, BCVA was logMAR 0.2 and optical coherence tomography (OCT) revealed the presence of cystoid macular edema caused by vitreomacular traction (VMT). The patient was scheduled for intravitreal ocriplasmin injection. Prior to treatment, the vision improved spontaneously to logMAR 0.1, and no VMT could be detected with spectral domain (SD)-OCT. The ocriplasmin injection was deferred but 3 weeks later the patient presented again with metamorphopsia, while VMT was again evident on SD-OCT. Ocriplasmin was injected and 1 month later the BCVA reached logMAR 0.1 without VMT. However, at 2 months post injection the VMT reappeared and a conservative approach with observation and topical nepafenac administration was decided. At the 3-month post-injection visit there was no VMT. More than 3 years after the ocriplasmin injection there is still no evidence of VMT, the patient is free of metamorphopsia, and his BCVA is logMAR 0.0. CONCLUSION Separation of consecutive layers of the vitreous cortex (vitreoschisis) may account for recurrent VMT.
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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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Napolitano F, Di Iorio V, Di Iorio G, Melone MAB, Gianfrancesco F, Simonelli F, Esposito T, Testa F, Sampaolo S. Early posterior vitreous detachment is associated with LAMA5 dominant mutation. Ophthalmic Genet 2018; 40:39-42. [PMID: 30589377 DOI: 10.1080/13816810.2018.1558261] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Extracellular matrix molecular components, previously linked to multisystem syndromes include collagens, fibrillins and laminins. Recently, we described a novel multisystem syndrome caused by the c.9418G>A p.(V3140M) mutation in the laminin alpha-5 (LAMA5) gene, which affects connective tissues of all organs and apparatus in a three generation family. In the same family, we have also reported a myopic trait, which, however, was linked to the Prolyl 4-hydroxylase subunit alpha-2 (P4HA2) gene. Results of investigation on vitreous changes and their pathogenesis are reported in the present study. MATERIALS AND METHODS Nineteen family individuals underwent complete ophthalmic examination including best-corrected visual acuity (BCVA), fundus examination, fundus photography, intraocular pressure measurement, axial length measurement using ocular biometry, Goldmann visual field examination, standard electroretinogram, SD-OCT. Segregation analysis of LAMA5 and P4HA2 mutations was performed in enrolled members. RESULTS The vitreous alterations fully segregated with LAMA5 mutation in both young and adult family members. Slight reduction of retinal thickness and peripheral retinal degeneration in only two patients were reported. CONCLUSIONS In this work we showed that PVD is a common trait of LAMA5 multisystem syndrome, therefore occurring as an age-unrelated trait. We hypothesize that the p.(V3140M) mutation results in a reduction of retinal inner limiting membrane (ILM) stability, leading to a derangement in the macromolecular structure of the vitreous gel, and PVD. Further investigations will be necessary to elucidate the role of wild type and mutated LAMA5 in the pathogenesis of PVD.
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Affiliation(s)
- Filomena Napolitano
- a Neurology Clinic II, Department of Medical Sciences, Surgery, Neurology, Metabolic Diseases and Geriatrics , University of Campania Luigi Vanvitelli , Naples , Italy.,b Institute of Genetics and Biophysics "Adriano Buzzati-Traverso" , National Research Council , Naples , Italy
| | - Valentina Di Iorio
- c Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Giuseppe Di Iorio
- a Neurology Clinic II, Department of Medical Sciences, Surgery, Neurology, Metabolic Diseases and Geriatrics , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Mariarosa Anna Beatrice Melone
- a Neurology Clinic II, Department of Medical Sciences, Surgery, Neurology, Metabolic Diseases and Geriatrics , University of Campania Luigi Vanvitelli , Naples , Italy.,d Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology , Temple University , Philadelphia , PA , USA
| | - Fernando Gianfrancesco
- b Institute of Genetics and Biophysics "Adriano Buzzati-Traverso" , National Research Council , Naples , Italy
| | - Francesca Simonelli
- c Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Teresa Esposito
- b Institute of Genetics and Biophysics "Adriano Buzzati-Traverso" , National Research Council , Naples , Italy.,e IRCCS INM Neuromed , Pozzilli , IS , Italy
| | - Francesco Testa
- c Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Simone Sampaolo
- a Neurology Clinic II, Department of Medical Sciences, Surgery, Neurology, Metabolic Diseases and Geriatrics , University of Campania Luigi Vanvitelli , Naples , Italy
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7.1 T MRI and T2 mapping of the human and porcine vitreous body post mortem. Eur J Pharm Biopharm 2018; 131:82-91. [DOI: 10.1016/j.ejpb.2018.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 12/30/2022]
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10
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Jiang X, Peng Y, Yang C, Liu W, Han B. The feasibility study of an in situ
marine polysaccharide-based hydrogel as the vitreous substitute. J Biomed Mater Res A 2018; 106:1997-2006. [DOI: 10.1002/jbm.a.36403] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/06/2018] [Accepted: 03/15/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Xiaolei Jiang
- College of Marine Life Sciences, Ocean University of China; Qingdao Shandong China
| | - Yanfei Peng
- College of Marine Life Sciences, Ocean University of China; Qingdao Shandong China
| | - Chaozhong Yang
- School of Medicine; Heze Medical College; Heze Shandong China
| | - Wanshun Liu
- College of Marine Life Sciences, Ocean University of China; Qingdao Shandong China
| | - Baoqin Han
- College of Marine Life Sciences, Ocean University of China; Qingdao Shandong China
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Vitreous and macular hole: genesis and nemesis. SPEKTRUM DER AUGENHEILKUNDE 2017. [DOI: 10.1007/s00717-017-0377-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Romano MR, Comune C, Ferrara M, Cennamo G, De Cillà S, Toto L, Cennamo G. Retinal Changes Induced by Epiretinal Tangential Forces. J Ophthalmol 2015; 2015:372564. [PMID: 26421183 PMCID: PMC4573429 DOI: 10.1155/2015/372564] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 06/11/2015] [Accepted: 06/22/2015] [Indexed: 12/05/2022] Open
Abstract
Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.
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Affiliation(s)
- Mario R. Romano
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, University Federico II, Napoli, Italy
| | - Chiara Comune
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, University Federico II, Napoli, Italy
| | - Mariantonia Ferrara
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, University Federico II, Napoli, Italy
| | - Gilda Cennamo
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, University Federico II, Napoli, Italy
| | - Stefano De Cillà
- Azienda Ospedaliero-Universitaria “Maggiore della Carità” di Novara, 28100 Novara, Italy
| | - Lisa Toto
- Ophthalmology Clinic, University G. d'Annunzio of Chieti-Pescara, 66100 Chieti, Italy
| | - Giovanni Cennamo
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, University Federico II, Napoli, Italy
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Chang J, Tao Y, Wang B, Guo BH, Xu H, Jiang YR, Huang Y. An in situ-forming zwitterionic hydrogel as vitreous substitute. J Mater Chem B 2015; 3:1097-1105. [DOI: 10.1039/c4tb01775g] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An in situ-forming zwitterionic gel as vitreous substitute.
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Affiliation(s)
- Jing Chang
- Key Laboratory of Advanced Materials (MOE)
- Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Yong Tao
- Department of Ophthalmology
- People's Hospital
- Peking University
- Key Laboratory of Vision Loss and Restoration
- Ministry of Education
| | - Bin Wang
- Department of Ophthalmology
- People's Hospital
- Peking University
- Key Laboratory of Vision Loss and Restoration
- Ministry of Education
| | - Bao-hua Guo
- Key Laboratory of Advanced Materials (MOE)
- Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Hong Xu
- College of Food Science and Light Industry
- Nanjing Tech University
- Nanjing 211816
- China
| | - Yan-rong Jiang
- Department of Ophthalmology
- People's Hospital
- Peking University
- Key Laboratory of Vision Loss and Restoration
- Ministry of Education
| | - Yanbin Huang
- Key Laboratory of Advanced Materials (MOE)
- Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
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Yamazaki J, Yoshida M, Mizunuma H. Experimental analyses of the retinal and subretinal haemorrhages accompanied by shaken baby syndrome/abusive head trauma using a dummy doll. Injury 2014; 45:1196-206. [PMID: 24810668 DOI: 10.1016/j.injury.2014.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/11/2014] [Accepted: 04/05/2014] [Indexed: 02/02/2023]
Abstract
INTRODUCTION We explored several modes of violent shaking using a dummy doll with an eyeball model to reproduce abusive events that lead to retinal haemorrhages (RH) seen in shaken baby syndrome or abusive head trauma (SBS/AHT). MATERIALS AND METHODS A dummy doll equipped with an eyeball model was prepared. The eyeball model was filled with a model of vitreous body, i.e. agar gel or water, and was with a pressure sensor to measure normal stress. RESULTS The modes of shaking were classified into three patterns, i.e. fast shaking with the fore arms, fast shaking with the whole arms and synchronized shaking with the whole arms. The frequency of the cyclic acceleration-deceleration history experienced by the head of the dummy doll was 5.0, 4.0 and 2.2 Hz, respectively, with the maximum acceleration of 20, 20 and 60 m/s(2), respectively. We considered the last of these three modes of shaking as possibly corresponding to the worst case of violent shaking. This mode of shaking could be instructed to volunteers who acted as imitate perpetrators, and resulted in both increased peak intensities of the acceleration experienced by the head of the dummy doll and increased stresses on the retina at the posterior pole of the eyeball model. DISCUSSION The time integral of the stress through a single cycle of shaking was 107 Pa·s, much larger than that of a single event of fall, which resulted in 60-73 Pa·s. Taking into account that abusive shaking is likely to include multiple cycles, the time integral of the stress due to abusive shaking can be even larger. This clear difference may explain why RH in SBS/AHT is frequent, while RH in accidental falls is rare.
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Affiliation(s)
- Junpei Yamazaki
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Makoto Yoshida
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Hiroshi Mizunuma
- Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
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Donati S, Caprani SM, Airaghi G, Vinciguerra R, Bartalena L, Testa F, Mariotti C, Porta G, Simonelli F, Azzolini C. Vitreous substitutes: the present and the future. BIOMED RESEARCH INTERNATIONAL 2014; 2014:351804. [PMID: 24877085 PMCID: PMC4024399 DOI: 10.1155/2014/351804] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 02/05/2023]
Abstract
Vitreoretinal surgery has advanced in numerous directions during recent years. The removal of the vitreous body is one of the main characteristics of this surgical procedure. Several molecules have been tested in the past to fill the vitreous cavity and to mimic its functions. We here review the currently available vitreous substitutes, focusing on their molecular properties and functions, together with their adverse effects. Afterwards we describe the characteristics of the ideal vitreous substitute. The challenges facing every ophthalmology researcher are to reach a long-term intraocular permanence of vitreous substitute with total inertness of the molecule injected and the control of inflammatory reactions. We report new polymers with gelification characteristics and smart hydrogels representing the future of vitreoretinal surgery. Finally, we describe the current studies on vitreous regeneration and cell cultures to create new intraocular gels with optimal biocompatibility and rheological properties.
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Affiliation(s)
- Simone Donati
- Department of Surgical and Morphological Sciences, Section of Ophthalmology, School of Medicine, University of Insubria, Via Guicciardini 9, 21100 Varese, Italy
| | - Simona Maria Caprani
- Department of Surgical and Morphological Sciences, Section of Ophthalmology, School of Medicine, University of Insubria, Via Guicciardini 9, 21100 Varese, Italy
| | - Giulia Airaghi
- Department of Surgical and Morphological Sciences, Section of Ophthalmology, School of Medicine, University of Insubria, Via Guicciardini 9, 21100 Varese, Italy
| | - Riccardo Vinciguerra
- Department of Surgical and Morphological Sciences, Section of Ophthalmology, School of Medicine, University of Insubria, Via Guicciardini 9, 21100 Varese, Italy
| | - Luigi Bartalena
- Endocrine Unit, Department of Clinical and Experimental Medicine, School of Medicine, University of Insubria, 21100 Varese, Italy
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Second University of Naples, 80121 Naples, Italy
| | - Cesare Mariotti
- Department of Ophthalmology, Polytechnic University of Ancona, 60121 Ancona, Italy
| | - Giovanni Porta
- Genetic Laboratory, Department of Surgical and Morphological Sciences, School of Medicine, University of Insubria, 21100 Varese, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Second University of Naples, 80121 Naples, Italy
| | - Claudio Azzolini
- Department of Surgical and Morphological Sciences, Section of Ophthalmology, School of Medicine, University of Insubria, Via Guicciardini 9, 21100 Varese, Italy
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Annaka M, Mortensen K, Vigild ME, Matsuura T, Tsuji S, Ueda T, Tsujinaka H. Design of an Injectable in Situ Gelation Biomaterials for Vitreous Substitute. Biomacromolecules 2011; 12:4011-21. [DOI: 10.1021/bm201012f] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masahiko Annaka
- Department
of Chemistry, Kyushu University, Fukuoka
812-8581, Japan
- International
Research Center
for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
| | - Kell Mortensen
- Department of Natural Sciences, University of Copenhagen, Thorvaldsensvej 40, DK1871
Frederiksberg C, Denmark
| | - Martin E. Vigild
- Danish Polymer Center and Department
of Chemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Toyoaki Matsuura
- Department of Ophthalmology, Nara Medical University, Kashihara, Nara 634-8522,
Japan
| | - Souichiro Tsuji
- Department
of Chemistry, Kyushu University, Fukuoka
812-8581, Japan
| | - Tetsuo Ueda
- Department of Ophthalmology, Nara Medical University, Kashihara, Nara 634-8522,
Japan
| | - Hiroki Tsujinaka
- Department of Ophthalmology, Nara Medical University, Kashihara, Nara 634-8522,
Japan
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Baino F. Towards an ideal biomaterial for vitreous replacement: Historical overview and future trends. Acta Biomater 2011; 7:921-35. [PMID: 21050899 DOI: 10.1016/j.actbio.2010.10.030] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 10/22/2010] [Accepted: 10/27/2010] [Indexed: 02/03/2023]
Abstract
Removal of the natural vitreous body from the eye and its substitution with a tamponade agent may be necessary in cases of complicated retinal detachment. Many materials have been variously proposed and tested over the years in an attempt to find an ideal vitreous substitute. This review highlights the evolution of research in the field of vitreous replacement and chronicles the main advances that have been made in such a context. The suitability and limitations of vitreous tamponade agents and substitutes in current clinical use are examined, and the future promise of experimentally tested biomaterials are described and discussed. Future trends in research are also considered and, specifically, the great potential of polymeric hydrogels is emphasized, as they seem to be very effective in closely mimicking the features of the natural vitreous and they could successfully act as long-term vitreous substitutes without inducing clinical complications in the patient's eye.
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Affiliation(s)
- Francesco Baino
- Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
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18
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Wilson CG, Tan LE, Mains J. Principles of Retinal Drug Delivery from Within the Vitreous. DRUG PRODUCT DEVELOPMENT FOR THE BACK OF THE EYE 2011. [DOI: 10.1007/978-1-4419-9920-7_6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Baino F. Scleral buckling biomaterials and implants for retinal detachment surgery. Med Eng Phys 2010; 32:945-56. [DOI: 10.1016/j.medengphy.2010.07.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/25/2010] [Accepted: 07/14/2010] [Indexed: 11/28/2022]
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20
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The Use of Polymers in the Treatment of Retinal Detachment: Current Trends and Future Perspectives. Polymers (Basel) 2010. [DOI: 10.3390/polym2030286] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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22
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Hans SA, Bawab SY, Woodhouse ML. A finite element infant eye model to investigate retinal forces in shaken baby syndrome. Graefes Arch Clin Exp Ophthalmol 2008; 247:561-71. [PMID: 19052768 DOI: 10.1007/s00417-008-0994-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/10/2008] [Accepted: 10/29/2008] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Shaken baby syndrome (SBS) is a form of abuse in which an infant, typically 6 months or less, is held and submitted to repeated acceleration-deceleration forces. One of the indicators of abuse is bilateral retinal hemorrhaging. A computational model of an infant eye, using the finite element method, is built in order to assess forces at the posterior retina for a shaking and an impact motions. METHOD The eye model is based on histological studies, diagrams, and materials from previous literature. Motions are applied to the model to simulate a four-cycle shaking motion in 1 second with maximum extension/flexion of the neck. The retinal forces of the shaking motion, at the posterior eye, are compared to an impact pulse (60G) simulating a fall for a total duration of 100 ms. RESULTS The shaking motion, for the first cycle, shows retinal force means at the posterior eye to be around 0.08 N sustained from the time range of 50 to 200 ms, into the shake, with a peak in excess of 0.2 N. The impulse, area under the curve, is 15 N-ms for 250 msec for the first cycle. The impact simulation reveals a mean retinal force around 0.025 N for a time range of 0 to 26 ms, with a peak force around 0.11 N. Moreover, the impulse for the impact simulation is 13 times lower than the shaking motion. CONCLUSION The results suggest that shaking alone may be enough to cause retinal hemorrhaging, as there are more sustained and higher forces in the posterior retina, compared to an impact due to a fall. This is in part due to the optic nerve causing more localized stresses in a shaking motion than an impact.
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Affiliation(s)
- Steven Alex Hans
- Department of Mechanical Engineering, Old Dominion University, Norfolk, VA 23529-0247, USA.
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Affiliation(s)
- J. Sebag
- University of Southern California, Huntington Beach, CA USA
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24
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Sebag J, Ansari RR, Suh KI. Pharmacologic vitreolysis with microplasmin increases vitreous diffusion coefficients. Graefes Arch Clin Exp Ophthalmol 2006; 245:576-80. [PMID: 16941141 DOI: 10.1007/s00417-006-0394-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 06/07/2006] [Accepted: 06/10/2006] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Pharmacologic vitreolysis is a new approach to improve vitreo-retinal surgery and ultimately to liquefy and detach the vitreous from the retina to eliminate the contribution of the vitreous to retinopathy. The mechanism of action of the agents being developed for pharmacologic vitreolysis remains unclear. The effect of microplasmin on vitreous diffusion coefficients was investigated using the non-invasive technique of dynamic light scattering (DLS). METHODS Vitreous diffusion coefficients in 18 intact porcine eyes were measured in vitro with dynamic light scattering (DLS). DLS was performed on all specimens at 37 degrees C 30 min after injections of human recombinant microplasmin at doses ranging from 0.125 to 0.8 mg, with 20-nm tracer nanospheres. RESULTS DLS findings in untreated porcine vitreous were similar to the previously described findings in bovine and human vitreous. Microplasmin increased porcine vitreous diffusion coefficients in a dose-dependent manner (correlation coefficient, r=0.93), with an 85% increase after a 30-min exposure to the maximum dose. CONCLUSIONS Pharmacologic vitreolysis with human recombinant microplasmin increases vitreous diffusion coefficients in vitro. The results of these studies have implications for the dosing, route of administration, duration of action and methods of determining efficacy in future studies of pharmacologic vitreolysis to enhance vitreo-retinal surgery, as well as the design of clinical trials to induce prophylactic posterior vitreous detachment.
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Affiliation(s)
- J Sebag
- VMR Institute, 7677 Center Avenue, suite 400, Huntington Beach, CA 92647, USA.
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Neal RE, Bettelheim FA, Lin C, Winn KC, Garland DL, Zigler JS. Alterations in human vitreous humour following cataract extraction. Exp Eye Res 2005; 80:337-47. [PMID: 15721616 DOI: 10.1016/j.exer.2004.09.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 09/24/2004] [Indexed: 10/26/2022]
Abstract
Cataract extraction is associated with the risk of posterior vitreous detachment, macular edema and retinal detachment possibly as a result of a disturbance to the vitreous body during surgery. While it is common for lens cortical fiber debris to leak into the vitreous humour during cataract extraction, the extent to which the vitreous humour is altered post-surgery is unknown. The current study examines the integrity of the vitreous humour of pseudophakic and phakic human donor eyes by comparing the proteome, the viscosity and the size distribution of macromolecules in different regions of the vitreous humour from human pseudophakic and phakic donor eyes. Major differences between the proteomes of anterior and posterior vitreous humour were observed in phakic and pseudophakic donor eyes. Seventeen spots identified as complete, modified or cleaved forms of alphaA-, alphaB-, betaA4-, betaB2, and gammaS-crystallins were present in the anterior vitreous humour of all pseudophakic eyes studied. Crystallins were not detected in the posterior vitreous humour of the pseudophakic eye or the vitreous humour of the phakic eye. Significant alterations in abundance and/or modification of transthyretin, alpha antitrypsin, and retinoic acid binding protein were observed in all locations of pseudophakic vitreous humour as compared to phakic samples. In addition, a significant decrease in the number and intensity of protein spots was observed for the posterior vitreous humour of pseudophakic eyes when compared to posterior vitreous humour of phakic eyes. Proteins which were affected include antioxidant proteins and enzymes such as carbonic anhydrase and trisephosphate isomerase. A reversal of the viscosity gradient, anterior to posterior, in the vitreous humour of pseudophakic eyes was observed concomitant with alterations in the distribution of 50 nm particles. These particles are likely primarily composed of hyaluronan. While varying degrees of vitreous degradation may have existed prior to surgery and may have contributed to the cataract formation, in no case did the phakic donor eyes exhibit the same alterations in the vitreous humour proteome, viscosity or particle sizes as did the pseudophakic donor eyes. The examination of phakic/pseudophakic donor eye pairs confirmed that the vitreous humour proteome and structural integrity were very similar in the matched phakic donor eye to eyes from donors with no history of cataract. Even though the number of samples for this study was limited, the observed changes support the hypothesis that alterations in the vitreous humour proteome occur in psuedophakic eyes with concurrent alterations in the structure of the vitreous humor. These modifications of the microenvironment of the retina may contribute to the development of retinal complications following cataract surgery.
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Affiliation(s)
- R E Neal
- National Eye Institute, National Institutes of Health, 7 Memorial Drive, MSC 0703, Bethesda, MD 20892-0703, USA.
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26
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Bettelheim FA, Zigler JS. Regional mapping of molecular components of human liquid vitreous by dynamic light scattering. Exp Eye Res 2004; 79:713-8. [PMID: 15500829 DOI: 10.1016/j.exer.2004.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Accepted: 07/30/2004] [Indexed: 11/18/2022]
Abstract
The distribution of particle sizes was studied in six regions of human liquid vitreous samples. Particle sizes were calculated from dynamic light scattering measurements as hydrodynamic diameter of molecules. In general, particle sizes increased progressively from anterior (near lens) to posterior (near retina). A much weaker trend of increase in particle size was found from nasal to temporal regions. Relative concentrations of particles of certain sizes were calculated from dynamic light scattering parameters. Viscosity coefficients of liquid vitreous samples were measured in a semi-micro viscometer. Hyaluronan concentrations increased from anterior to posterior and the reverse was true for viscosity, implying that the lower concentration of hyaluronan near the lens was offset by increased molecular size. A similar concentration gradient was found with the 6 nm diameter particles, and to a lesser degree with the 15 nm particles. The identities of these proteins must be resolved by techniques of proteomics.
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Affiliation(s)
- Frederick A Bettelheim
- Laboratory of Mechanisms of Ocular Diseases, National Eye Institute, NIH, 6, Center Drive, MSC 2735, Bethesda, MD 20892-2735, USA
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Sebag J. Seeing the invisible: the challenge of imaging vitreous. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:38-46. [PMID: 14715056 DOI: 10.1117/1.1627339] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Imaging the vitreous is an attempt to view what is by design invisible. The inability to adequately image vitreous hinders a more complete understanding of its normal structure and function and how these change in aging and disease. The combined use of more than one technique could provide better imaging for investigational and clinical purposes. Past and present imaging methodologies are summarized and research and clinical techniques that are currently in development for future applications, are discussed. Dark-field slit microscopy has been used to characterize vitreous anatomy, both within the vitreous body as well as at the vitreo-retinal interface. In addition to this methodology, slit-lamp biomicroscopy; direct, indirect, and scanning laser ophthalmoscopies; ultrasonography; optical coherence tomography; magnetic resonance and Raman spectroscopies; and dynamic light-scattering methodologies for noninvasive evaluation are presented. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography, but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy.
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Affiliation(s)
- J Sebag
- Doheny Eye Institute, University of Southern California, Huntington Beach, CA 92647, USA. jsebag@VMRinstitute@com
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Abstract
Purpose Imaging vitreous is a quest to view what is, by design, invisible. This treatise will review significant historical aspects, past and present imaging methodologies, and imaging techniques that are currently in development for future research and clinical applications. Methods Classic and modern histologic techniques, dark-field slit microscopy, clinical slit lamp biomicroscopy, standard and scanning laser ophthalmoscopy, ultrasonography, optical coherence tomography, magnetic resonance and raman spectroscopy, and dynamic light scattering methodologies are presented. Results The best available histologic techniques for imaging vitreous are those that avoid rapid dehydration of vitreous specimens. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy. Conclusions The inability to adequately image vitreous hinders a more complete understanding of its normal structure and how this changes in aging and disease. The combined use of more than one technique could provide better imaging of vitreous for future investigational and clinical purposes.
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Affiliation(s)
- J Sebag
- Associate Clinical Professor of Ophthalmology Doheny Eye Institute Keck School of Medicine University of Southern California CA 92648, USA.
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Ansari RR, Suh KI, Dunker S, Kitaya N, Sebag J. Quantitative molecular characterization of bovine vitreous and lens with non-invasive dynamic light scattering. Exp Eye Res 2001; 73:859-66. [PMID: 11846516 DOI: 10.1006/exer.2001.1097] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The non-invasive technique of dynamic light scattering (DLS) was used to quantitatively characterize vitreous and lens structure on a molecular level by measuring the sizes of the predominant particles and mapping the three-dimensional topographic distribution of these structural macromolecules in three spatial dimensions. The results of DLS measurements in five fresh adult bovine eyes were compared to DLS measurements in model solutions of hyaluronan (HA) and collagen (Coll). In the bovine eyes DLS measurements were obtained from excised samples of gel and liquid vitreous and compared to the model solutions. Measurements in whole vitreous were obtained at multiple points posterior to the lens to generate a three-dimensional 'map' of molecular structure. The macromolecule distribution in bovine lens was similarly characterized.In each bovine vitreous (Bo Vit) specimen, DLS predominantly detected two distinct particles, which differed in diffusion properties and hence size. Comparisons with model vitreous solutions demonstrated that these most likely corresponded to the Coll and HA components of vitreous. Three-dimensional mapping of Bo Vit found heterogeneity throughout the vitreous body, with different particle size distributions for Coll and HA at different loci. In contrast, the three-dimensional distribution of lens macromolecules was more homogeneous. Thus, the non-invasive DLS technique can quantitate the average sizes of vitreous and lens macromolecules and map their three-dimensional distribution. This method to assess quantitatively the macromolecular structure of vitreous and lens should be useful for clinical as well as experimental applications in health and disease.
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Affiliation(s)
- R R Ansari
- NASA Glenn Research Center, Cleveland, OH, USA
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Abstract
BACKGROUND Diabetes induces pathology throughout the body via nonenzymatic glycation of proteins. Vitreous, which is replete with type II collagen, undergoes significant changes in diabetes. The resultant diabetic vitreopathy plays an important role in diabetic retinopathy. Detecting these molecular changes could provide insight into diabetic eye disease as well as molecular effects elsewhere in the body. METHODS Human eyes were obtained at autopsy and studied in the fresh, unfixed state. Sclera, choroid, and retina were dissected off the vitreous for dark-field slit microscopy and dynamic light scattering (DLS). For the former, the entire vitreous was exposed. For the latter, only a window at the equator was dissected in some specimens, and the anterior segment was removed leaving the posterior lens capsule intact in others. DLS was performed to determine particle sizes at multiple sites 0.5 mm apart, spanning the globe at the equator (window dissections) and along the antero-posterior axis. RESULTS Dark-field slit microscopy in diabetic subjects detected findings typical of age-related vitreous degeneration, but at much younger ages than nondiabetic controls. Noninvasive DLS measurements found a greater heterogeneity and larger particle sizes in vitreous of subjects with diabetes as compared to age-matched controls. CONCLUSIONS DLS can detect and quantify the early molecular effects that cause vitreous collagen fibrils to cross-link and aggregate. This could provide valuable insight into ocular and systemic effects of hyperglycemia, because the molecular changes in diabetic vitreopathy could serve as an index of such effects throughout the body. In addition to the diagnostic implications, this methodology could provide a rapid, reproducible way to monitor the response to therapy with novel agents intended to prevent the complications of diabetes on a molecular level.
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Affiliation(s)
- J Sebag
- Doheny Eye Institute, University of Southern California, Los Angeles, California, USA.
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