Publicação
Retinal erythropoietin distribution and neuroprotective effect in a nanoparticulate drug delivery system after subconjunctival and topical administration in an animal glaucoma model
| Resumo: | ABSTRACT - Glaucoma is a neurodegenerative ocular disease with substantial impact in public health, as it causes retinal ganglion cells (RGC) degeneration and irreversible blindness. Neuroprotective strategies have been a focus of research in glaucoma, and the use of erythropoietin and its recombinant forms, like epoetin beta (EPOβ), have shown anti-apoptotic effects on RGC. We aimed to create a nanoformulation carrying EPOβ, adequate for topical ocular administration, that could provide neuroprotection to the retina in cases of glaucoma, with absent or residual secondary effects and the advantage of promoting patients’ compliance to the treatment. Therefore, chitosan and hyaluronic acid (CS/HA) nanoparticles for topical ocular deliver of epoetin beta (EPOβ) were developed, aiming to deliver EPOβ to the retina in a sustained profile. Firstly, in vitro and ex vivo studies of the physicochemical stability, cytotoxicity, release and permeation profiles and mucoadhesive strength of the CS/HA-EPOβ nanoparticles were performed. These nanoparticles allowed EPOβ permeation through ocular membranes in ex vivo assays, with no in vitro cytotoxicity. Afterwards, healthy Wistar Hannover rats were used for subconjunctival and topical administrations of CS/HA-EPOβ nanoparticles, to assess the formulation’s local and systemic influence, its biological tolerance and safety, its effect in retinal electrophysiology, and EPOβ’s distribution in ocular tissues. A sustained EPOβ delivery to the retina was observed using both routes of administration, with no side-effects. Finally, we explored the topical ocular delivery of CS/HA-EPOβ nanoparticles using a rat glaucoma model. We assessed retinal morphological and physiological changes in response to the nanoformulation applied through topical ocular route, using electroretinography and histological evaluation, which comprised immunofluorescence, hematoxylin and eosin staining and apoptosis assessment (cleaved caspase-3). Topical ocular administration of CS/HA EPOβ nanoparticles in glaucomatous rats allowed EPOβ permeation, including by transcorneal pathway, reaching the inner retina. Improvements in retinal electrical activity and thickness, and in apoptosis reduction occurred earlier and more significantly in the treatment group. In conclusion, EPOβ reached the retina, where its neuroprotective action was observed, thus demonstrating the feasibility of topical administration of neuroprotective agents in nanoformulations, targeting the posterior ocular segment. Results were promising and contribute to the development of new therapeutic strategies to preserve the visual acuity of patients with glaucoma or other neurodegenerative ocular diseases |
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| Autores principais: | Silva, Beatriz Rosa Fernandes Duarte da |
| Assunto: | Nanoparticles Chitosan Hyaluronic acid Epoetin beta Glaucoma Nanopartículas Quitosano Ácido hialurónico Epoetina beta Glaucoma |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | ABSTRACT - Glaucoma is a neurodegenerative ocular disease with substantial impact in public health, as it causes retinal ganglion cells (RGC) degeneration and irreversible blindness. Neuroprotective strategies have been a focus of research in glaucoma, and the use of erythropoietin and its recombinant forms, like epoetin beta (EPOβ), have shown anti-apoptotic effects on RGC. We aimed to create a nanoformulation carrying EPOβ, adequate for topical ocular administration, that could provide neuroprotection to the retina in cases of glaucoma, with absent or residual secondary effects and the advantage of promoting patients’ compliance to the treatment. Therefore, chitosan and hyaluronic acid (CS/HA) nanoparticles for topical ocular deliver of epoetin beta (EPOβ) were developed, aiming to deliver EPOβ to the retina in a sustained profile. Firstly, in vitro and ex vivo studies of the physicochemical stability, cytotoxicity, release and permeation profiles and mucoadhesive strength of the CS/HA-EPOβ nanoparticles were performed. These nanoparticles allowed EPOβ permeation through ocular membranes in ex vivo assays, with no in vitro cytotoxicity. Afterwards, healthy Wistar Hannover rats were used for subconjunctival and topical administrations of CS/HA-EPOβ nanoparticles, to assess the formulation’s local and systemic influence, its biological tolerance and safety, its effect in retinal electrophysiology, and EPOβ’s distribution in ocular tissues. A sustained EPOβ delivery to the retina was observed using both routes of administration, with no side-effects. Finally, we explored the topical ocular delivery of CS/HA-EPOβ nanoparticles using a rat glaucoma model. We assessed retinal morphological and physiological changes in response to the nanoformulation applied through topical ocular route, using electroretinography and histological evaluation, which comprised immunofluorescence, hematoxylin and eosin staining and apoptosis assessment (cleaved caspase-3). Topical ocular administration of CS/HA EPOβ nanoparticles in glaucomatous rats allowed EPOβ permeation, including by transcorneal pathway, reaching the inner retina. Improvements in retinal electrical activity and thickness, and in apoptosis reduction occurred earlier and more significantly in the treatment group. In conclusion, EPOβ reached the retina, where its neuroprotective action was observed, thus demonstrating the feasibility of topical administration of neuroprotective agents in nanoformulations, targeting the posterior ocular segment. Results were promising and contribute to the development of new therapeutic strategies to preserve the visual acuity of patients with glaucoma or other neurodegenerative ocular diseases |
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