1
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Chen LZ, Roos D, Philip E, Werth EG, Kostuk S, Yu H, Fuchs H. A Comprehensive Immunocapture-LC-MS/MS Bioanalytical Approach in Support of a Biotherapeutic Ocular PK Study. Pharmaceuticals (Basel) 2024; 17:193. [PMID: 38399408 PMCID: PMC10893151 DOI: 10.3390/ph17020193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/25/2024] Open
Abstract
BI-X, a therapeutic protein under development for the treatment of human ocular disease via intravitreal administration, binds to its therapeutic targets and endogenous albumin in the vitreous humor. A monkey ocular pharmacokinetic (PK) study following BI-X administration was conducted to measure drug and albumin levels in plasma, the vitreous humor, the aqueous humor, and retina tissue at various timepoints post-dose. A comprehensive bioanalytical approach was implemented in support of this study. Five immunocapture-LC-MS/MS assays were developed and qualified for quantitating BI-X in different matrices, while ELISA was used for albumin measurement. Immunocapture at the protein or peptide level was evaluated to achieve adequate assay sensitivity. Drug and albumin assays were applied for the analysis of the monkey study samples.
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Affiliation(s)
- Lin-Zhi Chen
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - David Roos
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - Elsy Philip
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - Emily G. Werth
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - Stephanie Kostuk
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - Hongbin Yu
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA (E.P.); (S.K.)
| | - Holger Fuchs
- Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach an der Riss, Germany;
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2
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Kaiser PK, Giani A, Fuchs H, Chong V, Heier JS. Factors That Can Prolong Ocular Treatment Duration in Age-Related Macular Degeneration. Ophthalmic Res 2023; 66:653-663. [PMID: 36626895 DOI: 10.1159/000527815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 10/09/2022] [Indexed: 01/11/2023]
Abstract
Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are used to treat wet age-related macular degeneration (wAMD); however, they are associated with a considerable treatment burden and poor real-world outcomes. The molecular size and charge of anti-VEGF agents influence drug pharmacokinetics in the vitreous and peak drug efficacy. This article reviews the established and novel strategies to prolong drug action, in the vitreal cavity, and thus reduce dosing frequency. Increased ocular residency can be attained by increasing drug size as with large molecules, such as KSI-301; adding polyethylene glycol to pegcetacoplan (APL-2) or avacincaptad pegol to increase molecular size; or binding to other targets that increase molecular size, such as vitreal albumin in the case of BI-X. Faricimab is a bispecific antibody in which the fragment crystallizable portion is engineered to prolong ocular residency and reduce systemic exposure. Conversely, small VEGF-binding molecules, such as brolucizumab, can be administered at higher clinical doses, with the potential for prolonged clinical activity versus larger molecules. Other important considerations include sustained drug delivery routes, such as the ranibizumab port delivery system or subconjunctival or suprachoroidal injection. More effective and longer-lasting treatments are needed for wAMD to prolong drug action and reduce dosing frequency. Several strategies are under investigation and the prevention of vision loss in patients with AMD or other retinal diseases may be attainable in the near future.
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Affiliation(s)
- Peter K Kaiser
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Andrea Giani
- Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany
| | - Holger Fuchs
- Boehringer Ingelheim International GmbH, Biberach an der Riss, Germany
| | | | - Jeffery S Heier
- Ophthalmic Consultants of Boston, Boston, Massachusetts, USA
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3
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Valencia E, García M, Fernández-Vega B, Pereiro R, Lobo L, González-Iglesias H. Targeted Analysis of Tears Revealed Specific Altered Metal Homeostasis in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:10. [PMID: 35426907 PMCID: PMC9034717 DOI: 10.1167/iovs.63.4.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Specific altered metal homeostasis has been investigated in the tear film of age-related macular degeneration (AMD) patients considering that metal dyshomeostasis contributes to the production of free radicals, inflammation, and apoptosis and results in conformational changes of proteins. Methods A multitargeted approach based on spectrophotometry and mass spectrometry techniques has been implemented to the multiplexed quantitation of lactoferrin (LF), S100 calcium binding protein A6 (S100A6), metallothionein 1A (MT1A), complement factor H (CFH), clusterin (CLU), amyloid precursor protein (APP), Mg, P, Na, Fe, Cu, Zn, and Ca, in the tear film from 60 subjects, 31 patients diagnosed with the dry form of AMD, and 29 healthy individuals Results Significant up-regulations of MT1A (1.9-fold) and S100A6 (1.4-fold) and down-regulations of LF (0.7-fold), Fe (0.6-fold), Mg (0.7-fold), and Cu (0.7-fold) were observed in AMD patients, when compared to control subjects. Of all the studied variables, only APP showed negative correlation with age in the AMD group. Also, positive correlations were observed for the variables Mg and Na, Cu and Mg, and P and Mg in both the AMD and control groups, whereas positive correlations were exclusively determined in the AMD group for Cu and LF, Na and Ca, and Mg and Ca. The panel constituted of MT1A, Na, and Mg predicts AMD disease in 73% of cases. Conclusions The different levels of target metals and (metallo-)proteins in the tear film suggest altered metal homeostasis in AMD patients. These observed pathophysiological changes may be related with the anomalous protein aggregation in the macula.
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Affiliation(s)
- Eva Valencia
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Montserrat García
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
| | - Beatriz Fernández-Vega
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
| | - Rosario Pereiro
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Lara Lobo
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Héctor González-Iglesias
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
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4
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Hauri S, Jakubiak P, Fueth M, Dengl S, Belli S, Alvarez-Sánchez R, Caruso A. Understanding the Half-Life Extension of Intravitreally Administered Antibodies Binding to Ocular Albumin. Pharmaceutics 2020; 12:E810. [PMID: 32858986 PMCID: PMC7559355 DOI: 10.3390/pharmaceutics12090810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/13/2020] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
The burden associated with frequent injections of current intravitreal (IVT) therapeutics may be reduced by long-acting delivery strategies. Binding to serum albumin has been shown to extend the ocular half-life in rabbits, however, the underlying molecular mechanisms and translational relevance remain unclear. The aim of this work was to characterize the in vitro and in vivo formation of complexes between human serum albumin (HSA) and an antigen-binding fragment of a rabbit antibody linked to an anti-HSA nanobody (FabA). The ocular and systemic pharmacokinetics of 3H-labeled FabA (0.05 mg/eye IVT) co-formulated with HSA (1 and 15 nmol/eye) were assessed in Dutch belted rabbits. Next, FabA was incubated in vitreous samples from cynomolgus monkeys and human donors (healthy and diseased) supplemented with species-specific serum albumin. Finally, the FabA-albumin complexes formed in vitro and in vivo were analyzed by radio-size exclusion chromatography. A 3-fold increase in FabA vitreal exposure and half-life was observed in rabbits co-administered with 15 nmol HSA compared to 1 nmol and a control arm. The different pharmacokinetic behavior was explained with the formation of higher molecular weight FabA-albumin complexes. The analysis of vitreous samples revealed the existence of predominantly 1:1 complexes at endogenous or low concentrations of supplemented albumin. A shift towards 1:2 complexes was observed with increasing albumin concentrations. Overall, these results suggest that endogenous vitreal albumin concentrations are insufficient for half-life extension and warrant supplementation in the dosing formulation.
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Affiliation(s)
- Simon Hauri
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
| | - Paulina Jakubiak
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
| | - Matthias Fueth
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
| | - Stefan Dengl
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, F. Hoffmann-La Roche Ltd., Nonnenwald 2, D-82377 Penzberg, Germany;
| | - Sara Belli
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
| | - Rubén Alvarez-Sánchez
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
| | - Antonello Caruso
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland; (P.J.); (M.F.); (S.B.); (R.A.-S.); (A.C.)
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5
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Gao Q, Schachar IH. An anchoring molecule increases intravitreal retention of antibody-based therapeutics used in the treatment of ocular diseases. J Control Release 2020; 328:263-275. [PMID: 32858075 DOI: 10.1016/j.jconrel.2020.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/13/2020] [Accepted: 08/18/2020] [Indexed: 11/17/2022]
Abstract
Intravitreal delivery of antibody-based therapeutics has revolutionized the treatment of intraocular vascular diseases involving the retina and choroid. Unfortunately, limited durability requires frequent retreatment placing an enormous burden on patients. We sought to solve this problem with a novel approach that uses an anchoring molecule characterized by two key molecular properties: (1) non-covalent binding to an antibody-based therapeutic, and (2) retention in the vitreous cavity. As an initial proof-of-principle, we chose an anchoring molecule composed of agarose microbeads functionalized with an Fc-binding domain. Bevacizumab was chosen as the antibody-based therapeutic. In vitro experiments demonstrated that bevacizumab was maximally bound to this anchoring molecule within 1 h, and was competitively released upon exposure to either polyclonal human (p < 0.0001) or rat (p = 0.0017) immunoglobulins. In silico modeling predicted prolonged intravitreal retention of an antibody-based therapeutic in the presence of this anchoring molecule, which was confirmed by in vivo experiments with this initial anchoring molecule in rats. This anchoring molecule increased the intraocular half-life of bevacizumab from 5.8 days to over 18 days and maintained therapeutic concentrations for over 80 days. Despite showing no evidence of direct cellular toxicity, this anchoring molecule collected in the anterior vitreous, partially obscuring retinal visualization and eliciting a mild chronic microglial/macrophage inflammatory response. These studies provide a plausible approach to the development of novel non-covalent methods of binding, retention, and release of antibody-based therapeutics in the vitreous.
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Affiliation(s)
- Quanqing Gao
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States
| | - Ira H Schachar
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States.
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6
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Schuster J, Koulov A, Mahler HC, Detampel P, Huwyler J, Singh S, Mathaes R. In Vivo Stability of Therapeutic Proteins. Pharm Res 2020; 37:23. [DOI: 10.1007/s11095-019-2689-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/16/2019] [Indexed: 01/05/2023]
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7
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Protein conjugates and fusion proteins as ocular therapeutics. Drug Discov Today 2019; 24:1440-1445. [DOI: 10.1016/j.drudis.2019.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/23/2019] [Accepted: 05/29/2019] [Indexed: 11/19/2022]
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8
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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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9
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Ulrich P, Blaich G, Baumann A, Fagg R, Hey A, Kiessling A, Kronenberg S, Lindecrona RH, Mohl S, Richter WF, Tibbitts J, Crameri F, Weir L. Biotherapeutics in non-clinical development: Strengthening the interface between safety, pharmacokinetics-pharmacodynamics and manufacturing. Regul Toxicol Pharmacol 2018; 94:91-100. [PMID: 29355662 DOI: 10.1016/j.yrtph.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 01/14/2018] [Indexed: 12/29/2022]
Abstract
Biological drugs comprise a wide field of different modalities with respect to structure, pharmacokinetics and pharmacological function. Considerable non-clinical experience in the development of proteins (e.g. insulin) and antibodies has been accumulated over the past thirty years. In order to improve the efficacy and the safety of these biotherapeutics, Fc modifications (e.g. Fc silent antibody versions), combinations (antibody-drug conjugates, protein-nanoparticle combinations), and new constructs (darpins, fynomers) have been introduced. In the last decade, advanced therapy medicinal products (ATMPs) in research and development have become a considerable and strongly growing part of the biotherapeutic portfolio. ATMPs consisting of gene and cell therapy modalities or even combinations of them, further expand the level of complexity, which already exists in non-clinical development strategies for biological drugs and has thereby led to a further diversification of expertise in safety and PKPD assessment of biological drugs. It is the fundamental rationale of the BioSafe meetings, held yearly in the EU and in the US, to convene experts on a regular basis and foster knowledge exchange and mutual understanding in this fast growing area. In order to reflect at least partially the variety of the biotherapeutics field, the 2016 EU BioSafe meeting addressed the following topics in six sessions: (i) In vitro Meets in vivo to Leverage Biologics Development (ii) New developments and regulatory considerations in the cell and gene therapy field (iii) CMC Challenges with Biologics development (iv) Minipigs in non-clinical safety assessment (v) Opportunities of PKPD Assessment in Less Common Administration Routes In the breakout sessions the following questions were discussed: (i) Cynomolgus monkey as a reprotoxicology Species: Impact of Immunomodulators on Early Pregnancy Maintenance (ii) Safety Risk of Inflammation and Autoimmunity Induced by Immunomodulators (iii) Experience with non-GMP Material in Pivotal Non-clinical Safety Studies to Support First in Man (FiM) Trials (iv) Safety Assessment of Combination Products for Non-oncology.
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Affiliation(s)
| | | | | | | | - Adam Hey
- Novartis Pharma, Basel, Switzerland
| | | | - Sven Kronenberg
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | | | - Silke Mohl
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | - Wolfgang F Richter
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | | | - Flavio Crameri
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
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10
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Fuchs H, Igney F. Binding to Ocular Albumin as a Half-Life Extension Principle for Intravitreally Injected Drugs: Evidence from Mechanistic Rat and Rabbit Studies. J Ocul Pharmacol Ther 2017; 33:115-122. [DOI: 10.1089/jop.2016.0083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Frederik Igney
- Department of Immune Modulation and Biotherapeutics Discovery, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
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11
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Rageh AA, Ferrington DA, Roehrich H, Yuan C, Terluk MR, Nelson EF, Montezuma SR. Lactoferrin Expression in Human and Murine Ocular Tissue. Curr Eye Res 2015; 41:883-9. [PMID: 26431065 DOI: 10.3109/02713683.2015.1075220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE Lactoferrin (LF) is a multifunctional protein known to provide innate defense due to its antimicrobial and anti-inflammatory properties. In the eye, LF has been identified in the tears and vitreous humor. Its presence in other ocular tissues has not been determined. Our aim is to assess the presence of LF in the cornea, iris, retina and retinal pigment epithelium (RPE) of humans and mice. METHODS To test for the endogenous production of LF, reverse transcription polymerase chain reaction was performed in cultured human cells from the cornea and RPE and in murine tissues. To confirm LF localization in specific ocular tissue, immunohistochemistry was performed on flat mounts of cornea, retina and RPE in human donor eyes. The presence of LF was assessed by western blotting in human and mouse ocular tissue and human culture cells (cornea and RPE). To verify antibody specificity, purified human LF and transferrin (TF) were used on 1D and 2D western blots. RESULTS LF gene expression was confirmed in the cornea and RPE cell cultures from humans, suggesting that LF is an endogenously produced protein. PCR results from mouse ocular tissue showed LF expression in cornea, iris, RPE, but not in retina. These results were also consistent with immunohistochemical localization of LF in human donor tissue. Antibody reaction for human LF was specific and western blotting showed its presence in the cornea, iris and RPE tissues. A faint reaction for the retina was observed but was likely due to contamination from other ocular tissues. Multiple commercially available antibodies for murine LF cross-reacted with TF, so no reliable results were obtained for murine western blot. CONCLUSION LF is expressed in multiple eye tissues of humans and mice. This widespread expression and multifunctional activity of LF suggests that it may play an important role in protecting eye tissues from inflammation-associated diseases.
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Affiliation(s)
- Abrar A Rageh
- a Department of Ophthalmology and Visual Neurosciences
| | | | - Heidi Roehrich
- b Histology Core for Vision Research , University of Minnesota , Minneapolis , MN , USA
| | - Ching Yuan
- a Department of Ophthalmology and Visual Neurosciences
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12
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Kuo HK, Chen YH, Huang F, Wu YC, Shiea J, Wu PC. The upregulation of zinc finger protein 670 and prostaglandin D2 synthase in proliferative vitreoretinopathy. Graefes Arch Clin Exp Ophthalmol 2015; 254:205-13. [DOI: 10.1007/s00417-015-3022-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 01/13/2023] Open
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13
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Montezuma SR, Dolezal LD, Rageh AA, Mar K, Jordan M, Ferrington DA. Lactoferrin Reduces Chorioretinal Damage in the Murine Laser Model of Choroidal Neovascularization. Curr Eye Res 2015; 40:946-53. [DOI: 10.3109/02713683.2014.969808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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14
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Rocha AS, Santos FM, Monteiro JP, Castro-de-Sousa JP, Queiroz JA, Tomaz CT, Passarinha LA. Trends in proteomic analysis of human vitreous humor samples. Electrophoresis 2014; 35:2495-508. [DOI: 10.1002/elps.201400049] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/02/2014] [Accepted: 05/02/2014] [Indexed: 12/17/2022]
Affiliation(s)
- Ana S. Rocha
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
- Chemistry Department; Faculty of Sciences, University of Beira Interior; Covilhã Portugal
| | - Fátima M. Santos
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
- Chemistry Department; Faculty of Sciences, University of Beira Interior; Covilhã Portugal
| | - João P. Monteiro
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
| | - João P. Castro-de-Sousa
- Medical Sciences Department; Faculty of Health sciences; University of Beira Interior; Covilhã Portugal
- Ophthalmology Service; Leiria-Pombal Hospital Center; Pombal Portugal
| | - João A. Queiroz
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
- Chemistry Department; Faculty of Sciences, University of Beira Interior; Covilhã Portugal
| | - Cândida T. Tomaz
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
- Chemistry Department; Faculty of Sciences, University of Beira Interior; Covilhã Portugal
| | - Luís A. Passarinha
- CICS-UBI - Health Sciences Research Centre; University of Beira Interior; Covilhã Portugal
- Medical Sciences Department; Faculty of Health sciences; University of Beira Interior; Covilhã Portugal
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15
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Murthy KR, Goel R, Subbannayya Y, Jacob HK, Murthy PR, Manda SS, Patil AH, Sharma R, Sahasrabuddhe NA, Parashar A, Nair BG, Krishna V, Prasad TK, Gowda H, Pandey A. Proteomic analysis of human vitreous humor. Clin Proteomics 2014; 11:29. [PMID: 25097467 PMCID: PMC4106660 DOI: 10.1186/1559-0275-11-29] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/16/2014] [Indexed: 12/11/2022] Open
Abstract
Background The vitreous humor is a transparent, gelatinous mass whose main constituent is water. It plays an important role in providing metabolic nutrient requirements of the lens, coordinating eye growth and providing support to the retina. It is in close proximity to the retina and reflects many of the changes occurring in this tissue. The biochemical changes occurring in the vitreous could provide a better understanding about the pathophysiological processes that occur in vitreoretinopathy. In this study, we investigated the proteome of normal human vitreous humor using high resolution Fourier transform mass spectrometry. Results The vitreous humor was subjected to multiple fractionation techniques followed by LC-MS/MS analysis. We identified 1,205 proteins, 682 of which have not been described previously in the vitreous humor. Most proteins were localized to the extracellular space (24%), cytoplasm (20%) or plasma membrane (14%). Classification based on molecular function showed that 27% had catalytic activity, 10% structural activity, 10% binding activity, 4% cell and 4% transporter activity. Categorization for biological processes showed 28% participate in metabolism, 20% in cell communication and 13% in cell growth. The data have been deposited to the ProteomeXchange with identifier PXD000957. Conclusion This large catalog of vitreous proteins should facilitate biomedical research into pathological conditions of the eye including diabetic retinopathy, retinal detachment and cataract.
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Affiliation(s)
- Krishna R Murthy
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, Kerala 690 525, India.,Vittala International Institute Of Ophthalmology, Bangalore, Karnataka 560085, India
| | - Renu Goel
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Department of Biotechnology, Kuvempu University, Shankaraghatta, Karnataka 577 451, India
| | - Yashwanth Subbannayya
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Harrys Kc Jacob
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Praveen R Murthy
- Vittala International Institute Of Ophthalmology, Bangalore, Karnataka 560085, India
| | - Srikanth Srinivas Manda
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Centre of Excellence in Bioinformatics, Bioinformatics Centre, School of Life Sciences, Pondicherry University, Puducherry 605 014, India
| | - Arun H Patil
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Rakesh Sharma
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences, Bangalore 560 006, India
| | | | | | - Bipin G Nair
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, Kerala 690 525, India
| | | | - Ts Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, Kerala 690 525, India.,Centre of Excellence in Bioinformatics, Bioinformatics Centre, School of Life Sciences, Pondicherry University, Puducherry 605 014, India
| | - Harsha Gowda
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Akhilesh Pandey
- Department of Biological Chemistry, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore 21205 MD, USA.,Department of Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore 21205 MD, USA
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16
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Intravitreal vascular endothelial growth factor. Graefes Arch Clin Exp Ophthalmol 2014; 252:583-8. [PMID: 24492935 DOI: 10.1007/s00417-014-2577-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/07/2014] [Accepted: 01/16/2014] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To evaluate whether a specific pre-analytical stabilization regimen is needed for naïve vitreous taps to detect true values of intrinsic VEGF levels. METHODS Fourteen consecutive patients with different vitreomacular pathologies without blood-retina-barrier breakdown were scheduled for standard 23-gauge three-port pars plana vitrectomy, and naïve vitreous taps were sampled at the beginning of each procedure. The extracted vitreous specimen was split; one half was immediately stored in a -20 °C freezer (unstabilized samples) and the other half was instantly stabilized with albumin (2.5 % final conc.), followed by arginine stabilization (1.25 M final conc.) and consecutively stored in a -20 °C freezer (stabilized samples). RESULTS Intravitreal VEGF was detected in all 14 analyzed samples (100 %). VEGF levels were shown to be 46.5 pg/ml ± 62.3 pg/ml (MV ± SD; range: 5.99-232.3 pg/ml) in unstabilized, and 120.4 pg/ml ± 94.4 pg/ml (range: 42.9 pg/ml-289.6 pg/ml) in stabilized vitreous samples. Intravitreal VEGF levels in stabilized vitreous samples were on average 2.6-fold, and thus significantly higher than in unstabilized taps of same eyes (p = 0.001, Wilcoxon test). VEGF levels in stabilized vitreous samples can be up to 8.5 times higher than in corresponding unstabilized vitreous taps of same eyes (bootstrap analysis). Intravitreal VEGF levels in unstabilized samples correlate with those in stabilized vitreous taps (r = 0.594; p = 0.025; Pearson). CONCLUSIONS An adequate pre-analytic stabilization regimen is needed to evaluate the most accurate intravitreal VEGF levels. This in turn will result in a better understanding of the physiological as well as pathological role of VEGF within the eye. Furthermore, knowing the true value of intravitreal VEGF levels will help to calculate the dosage of intravitrealy applied anti-VEGF drugs.
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17
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Hadziahmetovic M, Song Y, Ponnuru P, Iacovelli J, Hunter A, Haddad N, Beard J, Connor JR, Vaulont S, Dunaief JL. Age-dependent retinal iron accumulation and degeneration in hepcidin knockout mice. Invest Ophthalmol Vis Sci 2011; 52:109-18. [PMID: 20811044 DOI: 10.1167/iovs.10-6113] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Iron dysregulation can cause retinal disease, yet retinal iron regulatory mechanisms are incompletely understood. The peptide hormone hepcidin (Hepc) limits iron uptake from the intestine by triggering degradation of the iron transporter ferroportin (Fpn). Given that Hepc is expressed in the retina and Fpn is expressed in cells constituting the blood-retinal barrier, the authors tested whether the retina may produce Hepc to limit retinal iron import. METHODS Retinas of Hepc(-/-) mice were analyzed by histology, autofluorescence spectral analysis, atomic absorption spectrophotometry, Perls' iron stain, and immunofluorescence to assess iron-handling proteins. Retinal Hepc mRNA was evaluated through qPCR after intravitreal iron injection. Mechanisms of retinal Hepc upregulation were tested by Western blot analysis. A retinal capillary endothelial cell culture system was used to assess the effect of exogenous Hepc on Fpn. RESULTS Hepc(-/-) mice experienced age-dependent increases in retinal iron followed by retinal degeneration with autofluorescent RPE, photoreceptor death, and subretinal neovascularization. Hepc(-/-) mice had increased Fpn immunoreactivity in vascular endothelial cells. Conversely, in cultured retinal capillary endothelial cells, exogenous Hepc decreased both Fpn levels and iron transport. The retina can sense increased iron levels, upregulating Hepc after phosphorylation of extracellular signal regulated kinases. CONCLUSIONS These findings indicate that Hepc is essential for retinal iron regulation. In the absence of Hepc, retinal degeneration occurs. Increases in Hepc mRNA levels after intravitreal iron injection combined with Hepc-mediated decreases in iron export from cultured retinal capillary endothelial cells suggest that the retina may use Hepc for its tissue-specific iron regulation.
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18
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Shitama T, Hayashi H, Noge S, Uchio E, Oshima K, Haniu H, Takemori N, Komori N, Matsumoto H. Proteome Profiling of Vitreoretinal Diseases by Cluster Analysis. Proteomics Clin Appl 2008; 2:1265-1280. [PMID: 19081814 DOI: 10.1002/prca.200800017] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Vitreous samples collected in retinopathic surgeries have diverse properties, making proteomics analysis difficult. We report a cluster analysis to evade this difficulty. Vitreous and subretinal fluid samples were collected from 60 patients during surgical operation of non-proliferative diabetic retinopathy, proliferative diabetic retinopathy, proliferative vitreoretinopathy, and rhegmatogenous retinal detachment. For controls we collected vitreous fluid from patients of idiopathic macular hole, epiretinal, and from a healthy postmortem donor. Proteins from these samples were subjected to quantitative proteomics using two-dimensional gel electrophoresis. We selected 105 proteins robustly expressed among ca 400 protein spots and subjected them to permutation test. By using permutation test analysis we observed unique variations in the expression of some of these proteins in vitreoretinal diseases when compared to the control and to each other: 1) the levels of inflammation-associate proteins such as AAT, APOA4, ALB, and TF were significantly higher in all four types of vitreoretinal diseases, and 2) each vitreoretinal disease elevates a unique set of proteins which can be interpreted based on the pathology of retinopathy. Our protocol will be effective for the study of protein expression in other types of clinical samples of diverse property.
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Affiliation(s)
- Tomomi Shitama
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK73190, USA
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19
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Cumurcu T, Ozyurt H, Demir HD, Yardim H. Serum alpha-1-antitriypsin levels in patients with pseudoexfolative syndrome. Curr Eye Res 2008; 33:159-62. [PMID: 18293186 DOI: 10.1080/02713680701861752] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To evaluate the levels of serum alpha 1-antitrypsin in patients with pseudoexfoliation syndrome (PEX) and healthy control subjects without PEX. MATERIAL AND METHODS Forty-four patient with PEX and 40 healthy control subjects (84 subjects total) were enrolled into the study. Serum ATT levels were measured using nephelometry. RESULTS The mean serum AAT concentration in PEX group was significantly higher than in the controls (p=0.0001). CONCLUSION Serum AAT levels were found to be increased in patients with PEX. Increased serum AAT levels in PEX may explain the role of inflammation in this group of patients.
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Affiliation(s)
- Tongabay Cumurcu
- Department of Ophthalmology, Gaziosmanpasa University School of Medicine, Tokat, Turkey.
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20
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Funding M, Vorum H, Nexø E, Ehlers N. Alpha-1--antitrypsin in aqueous humour from patients with corneal allograft rejection. ACTA ACUST UNITED AC 2005; 83:379-84. [PMID: 15948795 DOI: 10.1111/j.1600-0420.2005.00457.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the presence and concentration of alpha1-antitrypsin in aqueous humour at the time of corneal rejection and to compare results obtained from patients with reversible and irreversible rejection. METHODS Samples of aqueous humour were obtained from 17 patients with acute corneal endothelial allograft rejection. The presence of alpha1-antitrypsin in aqueous humour was confirmed by immunoblotting and measured employing a sandwich ELISA. Total protein concentrations in aqueous humour were measured using Bradford's method. The outcome of corneal rejection episodes was determined 1 month after diagnosing corneal rejection and described as reversible or irreversible rejection. RESULTS alpha1-antitrypsin was detected in aqueous humour. Patients with reversible rejection had significantly higher alpha1-antitrypsin concentration than patients with irreversible rejection (p = 0.044). There was no significant difference in total protein concentrations (p = 0.745), and no correlation was found between alpha1-antitrypsin and total protein concentrations (p = 0.368). CONCLUSIONS alpha1-antitrypsin in aqueous humour seems to signal a favourable outcome of corneal rejection. The possible mechanism is discussed.
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Affiliation(s)
- Mikkel Funding
- Department of Ophthalmology, Arhus University Hospital, Arhus, Denmark.
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21
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Tseng W, Cortez RT, Ramirez G, Stinnett S, Jaffe GJ. Prevalence and risk factors for proliferative vitreoretinopathy in eyes with rhegmatogenous retinal detachment but no previous vitreoretinal surgery. Am J Ophthalmol 2004; 137:1105-15. [PMID: 15183797 DOI: 10.1016/j.ajo.2004.02.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2004] [Indexed: 11/16/2022]
Abstract
PURPOSE To determine the prevalence of and risk factors for proliferatative vitreoretinopathy (PVR) in eyes with rhegmatogenous retinal detachment but no previous vitreoretinal surgery. DESIGN Observational case series. METHODS Prospective study. SETTING A private vitreoretinal clinic in Caracas, Venezuela. STUDY POPULATION 119 eyes of 119 patients who presented with rhegmatogenous retinal detachment but no previous vitreoretinal surgery between 1995 and 1998. OBSERVATION PROCEDURES Data from detailed preoperative and postoperative examinations of each eye were recorded prospectively and entered into an electronic database. MAIN OUTCOME MEASURES Prevalence of PVR of any type and severe PVR, preoperative risk factors for PVR of any type and severe PVR, effect of PVR and retinal detachment duration on initial and final visual acuity, and surgical complexity. RESULTS The prevalence of PVR of any type was 52.9% and of severe PVR was 26.9%. The mean retinal detachment duration (+/-SD) was 58.4 (+/-129.1) days, and the mean time from initial examination to surgical treatment (+/-SD) was 24.3 (81.2) days. By univariable analysis, long retinal detachment duration, poor initial visual acuity, and large retinal detachment extent were significantly associated with PVR prevalence and severity. The presence of vitreous hemorrhage was significantly associated with PVR prevalence, and cataract was significantly associated with PVR severity. By multivariable analysis, long retinal detachment duration and large retinal detachment extent were simultaneous risk factors for PVR prevalence, while long retinal detachment, large retinal detachment extent, and poor initial visual acuity were simultaneous risk factors for PVR severity. Eyes with longer retinal detachment duration, PVR of any type, and severe PVR had worse initial and final visual acuities than eyes with shorter retinal detachment duration or those without PVR, respectively. Eyes with PVR had more complex surgery than those without PVR. CONCLUSIONS PVR occurred very frequently in this population and was associated with more complex surgery and worse visual outcomes than among eyes without PVR. We have identified preventable risk factors associated with PVR that suggest a specific and significant need for better access to ophthalmologic care and patient education in this group of patients.
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Affiliation(s)
- Wendy Tseng
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
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22
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Wu CW, Sauter JL, Johnson PK, Chen CD, Olsen TW. Identification and localization of major soluble vitreous proteins in human ocular tissue. Am J Ophthalmol 2004; 137:655-61. [PMID: 15059704 DOI: 10.1016/j.ajo.2003.11.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2003] [Indexed: 10/26/2022]
Abstract
PURPOSE To identify the major soluble proteins from human vitreous, and to establish a baseline for comparison of vitreous samples from eyes with various diseases. DESIGN Laboratory investigation. METHODS Normal vitreous was obtained from eight human donor eyes and from eight eyes of patients undergoing diabetic vitrectomy. Vitreous specimens were subjected to SDS-PAGE and MALDI-TOF-MS analysis. Six specific antibodies were used to identify proteins using Western blot. Four proteins were localized within ocular tissue in a normal donor eyebank eye. RESULTS We found eight distinct bands on SDS-PAGE in normal vitreous and two additional bands (hemoglobin) in eyes with diabetic retinopathy. Proteins were identified using MALDI-TOF-MS and confirmed by Western blot. We established a quantitative analysis of relative protein concentrations of undiluted vitreous. Immunohistochemistry localized selected proteins within the posterior segment layers. CONCLUSIONS We present a normal human vitreous protein profile using current technologies and provide a baseline for comparison to ocular disease states. Tissue distribution of vitreous proteins may help to elucidate more specific protein function.
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Affiliation(s)
- Charlie W Wu
- Department of Ophthalmology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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23
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González-Avila G, Lozano D, Manjarrez ME, Ruiz VM, Terán L, Vadillo-Ortega F, Selman M. Influence on collagen metabolism of vitreous from eyes with proliferative vitreoretinopathy. Ophthalmology 1995; 102:1400-5. [PMID: 9097780 DOI: 10.1016/s0161-6420(95)30857-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE Proliferative vitreoretinopathy (PVR) is characterized by cell proliferation and membrane formation on the vitreoretinal cavity of the eye. The membranes are composed of extracellular matrix, mainly collagen type I. To explore the possible mechanisms involved in PVR membrane formation, the authors analyzed the role of vitreous humor on collagen turnover. METHODS The authors studied vitreous samples from ten patients with PVR and from five donor eyes (keratoplasty) as the control group. Human lung fibroblasts were used to study the influence of vitreous on collagen synthesis and cell proliferation. Neutralizing antibodies against transforming growth factor-beta 2 (TGF-beta 2) were used to inhibit the fibroblast collagen synthesis induced by the vitreous samples. Collagenolytic activity was analyzed in vitreous fluid using 3H-labeled collagen. RESULTS The authors found that samples obtained from patients with PVR significantly increased collagen synthesis (2979 +/- 963.26 versus 800 +/- 232 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein; P < 0.00043), without affecting fibroblast replication. The collagen synthesis induced by the vitreous samples was inhibited by anti-TGF-beta 2 antibodies in both groups (0 and 481 +/- 59 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein for control and PVR samples, respectively). Collagenolytic activity was considerably lower in vitreous derived from PVR samples compared with the control group (19.9 +/- 20.3 versus 234.1 +/- 19.1 micrograms of degraded collagen per milligram of vitreous-incubated protein; P < 0.0032). CONCLUSION These results suggest that a combined mechanism, including an increase of collagen synthesis mediated at least in part by TGF-beta 2 and a decrease of collagen degradation, may contribute to the exaggerated deposition of collagen observed in PVR membranes, and that vitreous should be considered as a part of the microenvironment that is participating actively in the pathogenesis of this vitreoretinal disorder.
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Affiliation(s)
- G González-Avila
- Department of Molecular Biology, Instituto Nacional de Enfermedades Respiratorias, México City, México, DF
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McGahan MC, Grimes AM, Nasisse MP, Fleisher LN. Iron uptake by cultured lens epithelial cells. Graefes Arch Clin Exp Ophthalmol 1995; 233:354-9. [PMID: 7672622 DOI: 10.1007/bf00200484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Transferrin and Fe concentrations increase in the intraocular fluids in pathological conditions and the lens accumulates Fe during ocular inflammation. Tissues take up Fe from transferrin by two mechanisms, receptor-medicated endocytosis of diferric transferrin and a process occurring at the cell membrane which may be mediated by an oxido-reductase. However, Fe metabolism, transport and storage have not been previously investigated in the lens. This study was designed to characterize the uptake of Fe from transferrin by lens epithelial cells in culture. METHODS Primary, secondary and tertiary cultures of canine lens epithelial cells and cultures obtained from cataractous lenses were studied. Uptake of 59Fe from transferrin by these cultured cells was measured. Transferrin receptor populations were determined in receptor-binding assays. RESULTS There was a distinct relationship between the amount of Fe-transferrin added and the amount of Fe taken up, which was linear for the primary cultures but significantly reduced for the secondary, tertiary and cataract cultures (252 +/- 21, 169 +/- 14, 153 +/- 14 and 96 +/- 2 ng Fe/mg protein, respectively). Transferring receptor expression in lens cell cultures was reduced 10-fold within 2 days of addition of serum to cells grown in low-Fe, serum-free medium for 1 week. CONCLUSIONS The reduction of Fe uptake by the subcultured and cataract cell lines probably reflects a decrease in transferrin receptor expression and in the activity of an alternative pathway for Fe transferrin uptake occurring over time. This reduced Fe uptake may result from long-term exposure to relatively high Fe concentration in the media. A reduction in the expression of the transferrin receptor after incubation with high concentrations of Fe supports this conclusion.
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Affiliation(s)
- M C McGahan
- Department of Anatomy, Physiology and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
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25
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Casaroli Marano RP, Preissner KT, Vilaró S. Fibronectin, laminin, vitronectin and their receptors at newly-formed capillaries in proliferative diabetic retinopathy. Exp Eye Res 1995; 60:5-17. [PMID: 7536680 DOI: 10.1016/s0014-4835(05)80079-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Proliferative diabetic retinopathy (PDR) is characterized by intraocular formation of fibroglial vascularized tissue by active vasoproliferative mechanisms. Using immunocytochemistry, we have studied changes in the distribution pattern of fibronectin (FN), laminin (LN), vitronectin (VN) and their receptors in the newly-formed capillaries of PDR. In intraocular vascularized tissue of PDR patients, FN was present on both luminal and basal surfaces of endothelial cells, and was diffusely distributed in the interpericyte space. LN was also associated with the interpericyte space. VN was occasionally detected on the luminal capillary side, but was frequent in the basal aspect of the endothelium in the interpericyte space, where it was colocalized with FN. Beta-1 subunit complex receptors were detected on the luminal side, while alpha v beta 3 integrin was identified on both sides, more so in the luminal than in the basal endothelial domain. By slot-blotting techniques and densitometric analysis, increased concentrations of intravitreous FN and VN were found in PDR in comparison with normal samples. These results suggest that FN, VN and LN have a key role in the structural arrangement of newly formed capillaries in PDR, and that receptor expression could be involved in events of endothelial cell adhesion and proliferation.
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Sjöstrand J, Karlsson JO, Andersson AK. Changes in the soluble protein of the human vitreous in vitreoretinal disease. Acta Ophthalmol 1992; 70:814-9. [PMID: 1488893 DOI: 10.1111/j.1755-3768.1992.tb04893.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Samples of the vitreous were analysed in order to identify changes of soluble proteins in vitreo-retinal disease. The soluble proteins of the vitreous were separated on an anion exchange column (Mono-Q). The degree of neutral proteolytic activity in vitreous body was also measured. The vitreous from cataract cases without vitreoretinal disease was characterized by its low content of soluble proteins equivalent to about 1% of that of serum. Albumin and transferrin were the major identified components and their concentrations were approximately 0.85 and 0.03 g/l, respectively. In cases with vitreoretinal disease the vitreous showed changes of total soluble protein and the appearance of additional protein peaks. In patients with PVR the albumin concentration in the vitreous was found to be three times higher as compared to the control group consisting of patients with cataract. Neutral proteolytic activity in the vitreous was relatively low in both normal and pathological vitreous.
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Affiliation(s)
- J Sjöstrand
- Department of Ophthalmology, University of Gothenburg, Sweden
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Humorale Faktoren in der Genese der proliferativen Vitreoretinopathie: zur Bedeutung der Integrität der Blut-Retina-Schranke. SPEKTRUM DER AUGENHEILKUNDE 1991. [DOI: 10.1007/bf03163967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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