Development of a tissue-engineered eye model to test drug delivery systems
Abstract
One of the leading causes of blindness is diabetic retinopathy, a disease that affects the posterior segment of the eye. Injections are commonly used to treat diabetic retinopathy, but they can lead to discomfort and low patient compliance. Animal models are the current standard when obtaining preclinical data for new treatment options, but current research aims to create in vitro models that can reduce or replace the use of animal models. Therefore, the goal of this project was to develop a three-dimensional tissue model that can be used to test drug delivery systems created for the treatment of posterior eye diseases. Our model consists of two-modules that, when paired together, can replicate drug transport through the cornea and the interaction between the drug and the retinal endothelium. The first module represents the corneal epithelium, the main barrier of drug transport of the eye. The second module represents the vitreous humor and the retinal endothelium, the target cell layer for treatment of diabetic retinopathy. Results of this project show that we were able to establish a corneal epithelium and a retinal endothelium of human primary cells within each module. The corneal epithelium had 3-4 cell layers, showed cytokeratin-3 expression, but lacked expression of zonula occludens-1, a tight junction protein present in the cornea in vivo. The epithelium provided a barrier to paracellular transport, but permeability coefficients and transepithelial electrical resistance (TEER) values indicated the model had a weaker barrier after culturing at air-liquid interface when compared to remaining in submerged culture conditions. The retinal endothelium expressed both VCAM-1 and ICAM-1, cellular markers characteristic of activation, after exposure to TNF-a, a proinflammatory cytokine. Gene expression and secretion of inflammatory cytokines from the retinal endothelial cells were also significantly increased in response to TNF-a. Overall, we show that the cornea module provides a barrier to drug transport, and the retina module provides a retinal endothelium that can be activated in response to inflammation, similar to that expected in diabetic retinopathy.
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- OSU Theses [15752]