Recreating the retina to test harmful drugs

WAT (white adipose tissue)-on-a-chip preparation.

German scientists have developed “retina-on-a-chip”, a technology that combines living human cells with an artificial tissue-like system. Led by Peter Loskill of the Eberhard Karls University of Tubingen, and head of the research group on organ-on-a-chip technology at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, the work has been described in the latest issue of the journal “eLife”. This cutting-edge tool may prove a useful alternative to existing models for studying eye diseases and allowing scientists to test the effects of drugs on the retina more efficiently.

Many diseases that cause blindness harm the retina. The retina is also vulnerable to the harmful side effects of drugs used to treat diseases such as cancer. Currently, scientists often rely on animals or retina organoids, tiny retina-like structures grown from human stem cells, to study eye diseases and drug side effects. Results from studies in both models often fail to describe disease and drug effects accurately. Scientists at the Fraunhofer Institute tried to recreate a retina using engineering techniques.

“It is extremely challenging, if not almost impossible, to recapitulate the complex tissue architecture of the human retina solely using engineering approaches,” explained Christopher Probst, co-lead author of the study.

The scientists coaxed human pluripotent stem cells to develop into several different types of retina cells on artificial tissue. This tissue recreated the environment that cells would experience in the body and delivered nutrients and drugs to them through a system that mimicked human blood vessels. “This combination of approaches enabled us to successfully create a complex multilayer structure that includes all cell types and layers present in retinal organoids, connected to a retinal pigment epithelium layer,” said Kevin Achberger of the Eberhard Karls University, co-author of the study. “It is the first demonstration of a 3D retinal model that recreates many of the structural characteristics of the human retina and behaves in a similar way.” The team treated their retina-on-the-chip with the anti-malaria drug chloroquine and the antibiotic gentamicin, which are toxic to the retina. They found that the drugs had a toxic effect on the retinal cells in the model, suggesting that it could be a useful tool to test for harmful effects of drugs.