The understanding and treatment of degenerative retinal diseases such as age-related macular degeneration (AMD) should improve with the ability to 3D print eye tissue. National Institutes of Health and University of Amsterdam researchers successfully printed a combination of cells that form the outer blood-retina barrier, which supports the retina's light-sensing photoreceptors, to aid in the study of these diseases.

Different cell types primarily derived from patient stem cells were embedded in a hydrogel carrier, which was then printed on a biodegradable scaffold. The cells began to mature into a dense capillary networkGrowth of blood vessels across printed rows of the 3D-printed cell mixture. By day 7, blood vessels fill in the space between the rows, forming a network of capillaries. Source: Kapil Bharti/National Institutes of Health within days and reached maturity in six weeks, forming a tissue structure that mimics many of the features of the native tissue. The researchers hope that the technique will allow them to create an unlimited supply of eye tissue with which to study various eye diseases.

Under induced stress, the printed tissue exhibited patterns of early AMD, such as drusen deposits underneath the outer blood-retina barrier and progression to late dry stage AMD, where tissue degradation was observed. Low oxygen induced wet AMD-like appearance, with hyperproliferation of choroidal vessels that migrated into the sub- the retinal pigment epithelium zone. Drugs commonly used to treat AMD suppressed this vessel overgrowth and migration and restored tissue morphology.

The technology described in Nature Methods is expected to provide a theoretically unlimited supply of patient-derived tissue to study degenerative retinal diseases.