Abstract
Purpose :
Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped cornea progressively thins causing a cone-like bulge to develop. Biochemically, collagen content is decreased in keratoconus corneas. In this study we examine the effect of IVMED-80 on levels of lysinonorleucine (LNL), lysyl oxidase (LOX) activity and human cadaver corneas radial strain.
Methods :
Human keratoconus corneas were obtained from the patient undergoing corneal transplantation from Utah Lion Eye Bank. Each cornea was bisected and one half was incubated in 0.0016 mg/ml IVMED-80 Optisol for 1 week at 25°C and the other half was incubated in normal optisol.
The Cornea samples were washed with PBS and powdered in liquid nitrogen and targeted quantitation of LNL is performed using an Agilent 6490 triple quadrupole mass spectrometer fit with an Agilent 1290 UPLC system. LNL was chromatographically isolated using a Waters BEH-amide column. Retention times, collision energies and cell accelerator voltages were optimized using standards with dMRM transitions as [M+H]+→[m/z = 130.1, 84.2 and 271.2]..
Cornea stromal cells of normal and keratoconus human corneas were cultured (n=3 each) in 10% FBS DMEM were either exposed to BSS control or 0.0016 mg/mL CuSO4 (dissolved in BSS and then filtered through a 0.25µ filter). LOX enzyme activity in culture medium was measured using a peroxidase-coupled fluorometric assay using Amplex red 60. As a parallel assay, we added 500 µM aminopropionitrile (BAPN) which can inhibit LOX activity completely
Human cadaver corneas were cultured and treated group was immersed in 0.0016 mg/ml IVMED80 for 2 weeks. Cornea radial strain was obtained by applying pressure from 5 to 30 mmHg.
Results :
LC-MS outcomes showed an increase in LNL in IVMED80 treated keratoconus cornea.
Improved human cadaver corneas radial strain which supports the hypothesis that IVMED80 improves corneal collagen crosslinking and hence improves corneal biomechanical strength. A tenfold increase in LOX enzyme activity was seen in KCN cells following treatment with IVMED-80 compared to a fourfold increase in normal cells.
Conclusions :
We provide the evidence that IVMED-80 increases LOX activity and corneal stiffness in human keratoconic corneas ex vivo. IVMED80 can be beneficial for treatment for Keratoconus.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.