Nanotechnology and nanotoxicology in retinopathy

Abstract

Nanoparticles are nanometer-scaled particles, and can be utilized in the form of nanocapsules, nanoconjugates, or nanoparticles themselves for the treatment of retinopathy, including angiogensis-related blindness, retinal degeneration, and uveitis. They are thought to improve the bioavailability in the retina and the permeability of therapeutic molecules across the barriers of the eye, such as the cornea, conjunctiva, and especially, blood-retinal barriers (BRBs). However, consisting of multiple neuronal cells, the retina can be the target of neuronal toxicity of nanoparticles, in common with the central and peripheral nervous system. Furthermore, the ability of nanoparticles to pass through the BRBs might increase the possibility of toxicity, simultaneously promoting distribution in the retinal layers. In this regard, we discussed nanotechnology and nanotoxicology in the treatment of retinopathy.

Keywords: blood-retinal barrier; diabetic retinopathy; macular degeneration; nanoparticles; retinal degeneration; retinal diseases; toxicology; uveitis.

Figure 1

Clinical manifestations of representative diseases of retinopathy, as targets of nanoparticle-based medicine. (a) Angiogenesis-related blindness. Subretinal hemorrhage is observed in a patient with age-related macular degeneration (AMD), and retinal neovascularization is a characteristic found in patients with diabetic retinopathy (DR) and retinopathy of prematurity (ROP); (b) Retinal degeneration. Retinitis pigmentosa (RP) is characterized by diffusely degenerative retina with pigmented lesions. Stargardt disease is an inherited macular degeneration, and yellowish-white flecks are identified in the macula in this patient; (c) In the eye with uveitis, conjunctival injection (top) and keratoprecipitates (bottom) can be observed.

Figure 2

Characteristics of NPs affecting neuronal toxicity.