title: Experimental scleral cross-linking increases glaucoma damage in a mouse model.
abstract: The purpose of this study was to assess the effect of a scleral cross-linking agent on susceptibility to glaucoma damage in a mouse model.CD1 mice underwent 3 subconjunctival injections of 0.5 M glyceraldehyde (GA) in 1 week, then had elevated intraocular pressure (IOP) induced by bead injection. Degree of cross-linking was measured by enzyme-linked immunosorbent assay (ELISA), scleral permeability was measured by fluorescence recovery after photobleaching (FRAP), and the mechanical effects of GA exposure were measured by inflation testing. Control mice had buffer injection or no injection in 2 separate glaucoma experiments. IOP was monitored by Tonolab and retinal ganglion cell (RGC) loss was measured by histological axon counting. To rule out undesirable effects of GA, we performed electroretinography and detailed histology of the retina. GA exposure had no detectable effects on RGC number, retinal structure or function either histologically or electrophysiologically. GA increased cross-linking of sclera by 37% in an ELISA assay, decreased scleral permeability (FRAP, p = 0.001), and produced a steeper pressure-strain behavior by in vitro inflation testing. In two experimental glaucoma experiments, GA-treated eyes had greater RGC axon loss from elevated IOP than either buffer-injected or control eyes, controlling for level of IOP exposure over time (p = 0.01, and 0.049, multivariable regression analyses). This is the first report that experimental alteration of the sclera, by cross-linking, increases susceptibility to RGC damage in mice.
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA. Electronic address: fcone1@jhmi.edu.
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Kimball
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Cathy
authors.initials: C
authors.lastname: Nguyen
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Steinhart
authors.affiliation: The Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Thao D
authors.initials: TD
authors.lastname: Nguyen
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Pease
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Ericka N
authors.initials: EN
authors.lastname: Oglesby
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Oveson
authors.affiliation: Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Harry A
authors.initials: HA
authors.lastname: Quigley
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology*; D003432:Cross-Linking Reagents / Q000633:toxicity*; D004195:Disease Models, Animal; D004548:Elasticity / Q000187:drug effects; D004596:Electroretinography; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000378:metabolism; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D017127:Glycation End Products, Advanced / Q000378:metabolism; D005985:Glyceraldehyde / Q000633:toxicity*; D007429:Intraocular Pressure / Q000187:drug effects; D051379:Mice; D010539:Permeability; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012590:Sclera / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014065:Tonometry, Ocular
chemical_list: D003432:Cross-Linking Reagents; D005136:Eye Proteins; D017127:Glycation End Products, Advanced; D005985:Glyceraldehyde
keywords: Collagen; Cross-linking; Extracellular matrix; Glaucoma; Glyceraldehyde; Mouse; Retinal ganglion cell; Sclera