Fabricate 3D printable eye tissue to evaluate mechanisms underlying age-related macular degeneration and other eye diseases. This is the objective towards which a study was oriented, published in the journal Nature Methods, conducted by scientists of the National Eye Institute (NEI), part of the National Institutes of Health. The team, led by Kapil Bharti, used a combination of cells that form the outer blood-retinal barrier, the eye tissue that supports the light-sensitive photoreceptors in the retina. This approach, the authors explain, could provide an artificial patient-derived support for studying retinal degenerative diseases.
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The illness
“We know that age-related macular degeneration starts in the external blood-retinal barrier, but the mechanisms underlying disease progression are still unclear due to the lack of physiologically relevant human models.” The external blood-retinal barrier, experts explain, is made up of the retinal pigment epithelium (RPE), separated by Bruch’s membrane from the choriocapillary full of blood vessels. With age-related macular degeneration, the scientists add, deposits of lipoproteins form on the outside of Bruch’s membrane, limiting its function. The research team combined three types of immature choroidal cells, pericytes, endothelial cells and fibroblasts into one hydrogel. The result obtained was used to print a biodegradable scaffold in which cells can thrive and form a dense capillary network. After nine days, the authors seeded retinal pigment epithelial cells on the reverse side of the scaffold.
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The fabric
By day 42, the printed tissue has reached full maturity. The analyzes showed that the material obtained had an appearance and a behavior similar to the organic counterpart. When the experts subjected the substance to induced stress, the tissue showed degeneration patterns similar to those seen in human patients. The scientists then evaluated the effectiveness of anti-VEGF drugs in treating the condition, observing growth suppression and restoration of tissue morphology.
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“3D printing of this support – notes Bharti – could facilitate the study of a wide range of eye diseases”. “This work – concludes Marc Ferrer director of the 3D Tissue Bioprinting Laboratory at the National Center for Advancing Translational Sciences of the NIH – has many potential uses in translational applications, including therapeutic development. In the next steps the possibility of adding additional cell types will be tested to the printing process, such as immune cells, to better recapitulate native tissue.”
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