Accelerated oxygen-induced retinopathy is a reliable model of ischemia-induced retinal neovascularization

Retinal ischemia and pathological angiogenesis cause severe impairment of sight. Oxygen-induced retinopathy (OIR) in young mice is widely used as a model to investigate the underlying pathological mechanisms and develop therapeutic interventions. We compared directly the conventional OIR model (exposure to 75% O-2 from postnatal day (P) 7 to P12) with an alternative, accelerated version (85% O-2 from P8 to P11). We found that accelerated OIR induces similar pre-retinal neovascularization but greater retinal vascular regression that recovers more rapidly. The extent of retinal gliosis is similar but neuroretinal function, as measured by electroretinography, is better maintained in the accelerated model. We found no systemic or maternal morbidity in either model. Accelerated OIR offers a safe, reliable and more rapid alternative model in which pre-retinal neovascularization is similar but retinal vascular regression is greater

Recapitulation of Human Retinal Development from Human Pluripotent Stem Cells Generates Transplantable Populations of Cone Photoreceptors

Transplantation of rod photoreceptors, derived either from neonatal retinae or pluripotent stem cells (PSCs), can restore rod-mediated visual function in murine models of inherited blindness. However, humans depend more upon cone photoreceptors that are required for daylight, color, and high-acuity vision. Indeed, macular retinopathies involving loss of cones are leading causes of blindness. An essential step for developing stem cell-based therapies for maculopathies is the ability to generate transplantable human cones from renewable sources. Here, we report a modified 2D/3D protocol for generating hPSC-derived neural retinal vesicles with well-formed ONL-like structures containing cones and rods bearing inner segments and connecting cilia, nascent outer segments, and presynaptic structures. This differentiation system recapitulates human photoreceptor development, allowing the isolation and transplantation of a pure population of stage-matched cones. Purified human long/medium cones survive and become incorporated within the adult mouse retina, supporting the potential of photoreceptor transplantation for treating retinal degeneration

Observar per comprendre. Recull d’anàlisis d’usos i artefactes

Facultat de Belles Arts, Universitat de Barcelona. Assignatura: Artefactes i usos: disseny inclusiu, Curs: 2016-2017, Coordinador: Miquel Mallol Esquef

Intravitreal administration of recombinant human opticin protects against hyperoxia-induced pre-retinal neovascularization

Altres ajuts: Medical Research Council (grant no. MR/M025365/1)Opticin is an extracellular glycoprotein present in the vitreous. Its antiangiogenic properties offer the potential for therapeutic intervention in conditions such as proliferative diabetic retinopathy and retinopathy of prematurity. Here, we investigated the hypothesis that intravitreal administration of recombinant human opticin can safely protect against the development of pathological angiogenesis and promote its regression. We generated and purified recombinant human opticin and investigated its impact on the development and regression of pathological retinal neovascularization following intravitreal administration in murine oxygen-induced retinopathy. We also investigated its effect on normal retinal vascular development and function, following intravitreal injection in neonatal mice, by histological examination and electroretinography. In oxygen-induced retinopathy, intravitreal administration of human recombinant opticin protected against the development of retinal neovascularization to similar extent as aflibercept, which targets VEGF. Opticin also accelerated regression of established retinal neovascularization, though the effect at 18 h was less than that of aflibercept. Intravitreal administration of human recombinant opticin in neonatal mice caused no detectable perturbation of subsequent retinal vascular development or function. In summary we found that intraocular administration of recombinant human opticin protects against the development of pathological angiogenesis in mice and promotes its regression

Accelerated oxygen-induced retinopathy is a reliable model of ischemia-induced retinal neovascularization

Retinal ischemia and pathological angiogenesis cause severe impairment of sight. Oxygen-induced retinopathy (OIR) in young mice is widely used as a model to investigate the underlying pathological mechanisms and develop therapeutic interventions. We compared directly the conventional OIR model (exposure to 75% O-2 from postnatal day (P) 7 to P12) with an alternative, accelerated version (85% O-2 from P8 to P11). We found that accelerated OIR induces similar pre-retinal neovascularization but greater retinal vascular regression that recovers more rapidly. The extent of retinal gliosis is similar but neuroretinal function, as measured by electroretinography, is better maintained in the accelerated model. We found no systemic or maternal morbidity in either model. Accelerated OIR offers a safe, reliable and more rapid alternative model in which pre-retinal neovascularization is similar but retinal vascular regression is greater

Intravitreal administration of recombinant human opticin protects against hyperoxia-induced pre-retinal neovascularization

Opticin is an extracellular glycoprotein present in the vitreous. Its antiangiogenic properties offer the potential for therapeutic intervention in conditions such as proliferative diabetic retinopathy and retinopathy of prematurity. Here, we investigated the hypothesis that intravitreal administration of recombinant human opticin can safely protect against the development of pathological angiogenesis and promote its regression. We generated and purified recombinant human opticin and investigated its impact on the development and regression of pathological retinal neovascularization following intravitreal administration in murine oxygen-induced retinopathy. We also investigated its effect on normal retinal vascular development and function, following intravitreal injection in neonatal mice, by histological examination and electroretinography. In oxygen-induced retinopathy, intravitreal administration of human recombinant opticin protected against the development of retinal neovascularization to similar extent as aflibercept, which targets VEGF. Opticin also accelerated regression of established retinal neovascularization, though the effect at 18 h was less than that of aflibercept. Intravitreal administration of human recombinant opticin in neonatal mice caused no detectable perturbation of subsequent retinal vascular development or function. In summary we found that intraocular administration of recombinant human opticin protects against the development of pathological angiogenesis in mice and promotes its regression

Time courses of retinal vasculature regeneration and pre-retinal neovascular regression.

<p><b>(A, B)</b> Representative flat-mounted retinas from mice exposed to conventional OIR (75% O₂, upper panel) or accelerated OIR (85% O₂, lower panel) at 8 <b>(A, B)</b>, 11 <b>(A’, B’)</b> and 14 days after the end of hyperoxia <b>(A”,B”)</b>, showing progressive retinal vascular regeneration, and regression of the neovascular tufts. <b>(C, D)</b> Analysis of the persistent retinal vascular regression demonstrated more rapid vascular regeneration in the accelerated protocol at 11 days post-hyperoxia (p = 0.015). <b>(E, F)</b> No differences were found in the kinetics of regression of neovascular lesions between the two experimental conditions. Scale bars: 0.4 mm. n = 7–13 per group. Data are expressed as means ± SEM.</p

Molecular features and neuroretinal function.

<p><b>(A)</b> Retinal VEGF was measured by qPCR at intervals (0,1,2,3,5 and 8 days) following exposure to hyperoxia (n = 4–7 per group. <b>(B)</b> GFAP expression measured by qPCR (n = 5–7 per group). <b>(C)</b> Representative images of GFAP immunostaining in retinal sections from mice after the conventional and the accelerated protocol. <b>(C)</b> and <b>(C’)</b> show the variability within the conventional OIR group. <b>(D to G)</b> Electroretinographic (ERG) a-wave and b-wave amplitudes in scotopic conditions were measured at P26-27 <b>(D, E)</b> and at P60 <b>(F, G)</b> in mice previously exposed to the conventional and accelerated OIR protocols, and in age-matched non-OIR controls (n = 4–13 per group). Data are expressed as means ± SEM.</p

Retinal vasculature regression and pre-retinal neovascularization following hyperoxia and 5 days in room air.

<p><b>(A)</b> The extent of oxygen-induced retinal vascular regression was consistently greater (in 3 independent experimental groups) in the accelerated protocol (85% O₂ from P8 to P11) than in the conventional protocol (75% O₂ from P7 to P12). No significant differences were evident between independent experimental groups within each protocol, and the variances were similar (Barlett's test, p = 0.6429 for retinal vascular regression and p = 0.1415 for pre-retinal neovascularization). <b>(B)</b> Representative images show the extent of retinal vascular regression (delineated in white) in isolectin B4-stained flat-mounted retinas of mice in the conventional and the accelerated OIR protocols. Five days following return to room air, the extents of both persistent retinal vascular regression <b>(C)</b> and pre-retinal neovascularization <b>(D)</b> were similar in retinas of mice in both protocols. <b>(E)</b> Representative images of flat-mounted retinas of mice from the conventional and accelerated protocols illustrate the area of persistent retinal vascular regression (delineated in white), and the area of pre-retinal neovascularization (delineated in yellow). Scale bars: 0.5 mm. n = 6–14 per group. Data are expressed as means ± SEM.</p