Intravitreal pharmacokinetic study of the anti-angiogenic glycoprotein opticinCitation formats
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Intravitreal pharmacokinetic study of the anti-angiogenic glycoprotein opticin. / Del Amo, Eva M.; Griffiths, John R; Klaska, Izabela P; Hoke, Justin; White, Anne; Aarons, Leon; Cooper, Garth J.s.; Bainbridge, James W.b.; Bishop, Paul N; Unwin, Richard D.
In: Molecular Pharmaceutics, 21.05.2020.Research output: Contribution to journal › Article › peer-review
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T1 - Intravitreal pharmacokinetic study of the anti-angiogenic glycoprotein opticin
AU - Del Amo, Eva M.
AU - Griffiths, John R
AU - Klaska, Izabela P
AU - Hoke, Justin
AU - White, Anne
AU - Aarons, Leon
AU - Cooper, Garth J.s.
AU - Bainbridge, James W.b.
AU - Bishop, Paul N
AU - Unwin, Richard D.
PY - 2020/5/21
Y1 - 2020/5/21
N2 - Opticin is an endogenous vitreous glycoprotein that may have therapeutic potential as it has been shown that supra-normal concentrations supress preretinal neovascularisation. Herein we investigated the pharmacokinetics of opticin following intravitreal injection in rabbits. To measure simultaneously concentrations of human and rabbit opticin, a selected reaction monitoring mass spectrometry assay was developed. The mean concentration of endogenous rabbit opticin in 7 uninjected eyes was measured and found to be 19.2 nM or 0.62 µg/ml. When the vitreous was separated by centrifugation into a supernatant and collagen-containing pellet, 94 % of the rabbit opticin was in the supernatant. Intravitreal injection of human opticin (40 µg) into both eyes of rabbits was followed by enucleation at 5 h, 24 h, 72 h, 7 days, 14 days and 28 days post-injection (n=6 at each time point) and measurement of vitreous human and rabbit opticin concentrations in the supernatant and collagen-containing pellet following centrifugation. The volume of distribution of human opticin was calculated to be 3.31 ml and the vitreous half-life 4.2 days. Assuming that rabbit and human opticin are cleared from rabbit vitreous at the same rate, opticin is secreted into the vitreous at a rate of 0.14 µg/day. We conclude that intravitreally injected opticin has a vitreous half-life that is similar to currently available anti-angiogenic therapeutics. Whilst opticin was first identified bound to vitreous collagen fibrils, here we demonstrate that >90% of endogenous opticin is not bound to collagen. Endogenous opticin is secreted by the non-pigmented ciliary epithelium into the rabbit vitreous at a remarkably high rate and the turnover in vitreous is approximately 15% per day.
AB - Opticin is an endogenous vitreous glycoprotein that may have therapeutic potential as it has been shown that supra-normal concentrations supress preretinal neovascularisation. Herein we investigated the pharmacokinetics of opticin following intravitreal injection in rabbits. To measure simultaneously concentrations of human and rabbit opticin, a selected reaction monitoring mass spectrometry assay was developed. The mean concentration of endogenous rabbit opticin in 7 uninjected eyes was measured and found to be 19.2 nM or 0.62 µg/ml. When the vitreous was separated by centrifugation into a supernatant and collagen-containing pellet, 94 % of the rabbit opticin was in the supernatant. Intravitreal injection of human opticin (40 µg) into both eyes of rabbits was followed by enucleation at 5 h, 24 h, 72 h, 7 days, 14 days and 28 days post-injection (n=6 at each time point) and measurement of vitreous human and rabbit opticin concentrations in the supernatant and collagen-containing pellet following centrifugation. The volume of distribution of human opticin was calculated to be 3.31 ml and the vitreous half-life 4.2 days. Assuming that rabbit and human opticin are cleared from rabbit vitreous at the same rate, opticin is secreted into the vitreous at a rate of 0.14 µg/day. We conclude that intravitreally injected opticin has a vitreous half-life that is similar to currently available anti-angiogenic therapeutics. Whilst opticin was first identified bound to vitreous collagen fibrils, here we demonstrate that >90% of endogenous opticin is not bound to collagen. Endogenous opticin is secreted by the non-pigmented ciliary epithelium into the rabbit vitreous at a remarkably high rate and the turnover in vitreous is approximately 15% per day.
KW - opticin
KW - intravitreal pharmacokinetics
KW - Selected reaction monitoring mass spectrometry
KW - SLRP
KW - neovascularisation
U2 - 10.1021/acs.molpharmaceut.0c00151
DO - 10.1021/acs.molpharmaceut.0c00151
M3 - Article
JO - Molecular Pharmaceutics
JF - Molecular Pharmaceutics
SN - 1543-8384
ER -