Blind people have been given renewed hope of regaining their sight after laboratory-cultivated cells restored retinal function in mice, according to American scientists. The advancement demonstrates potential for novel eye treatments.
Stem Cell Breakthrough at Duke University
Biomedical engineers at Duke University in North Carolina utilised induced pluripotent stem cells (iPSCs) to cultivate specialised blood vessel cells vital to retinal health for the first time. When administered into mouse models of retinal disease, the "retinal endothelial cells" incorporated into compromised tissue to regenerate blood vessels and restore retinal function.
The research team also proved the cells' capacity to form functional retinal vascular tissue in a laboratory-cultivated environment, establishing a pathway to model and investigate various eye diseases. Their findings were published in the journal Nature Biomedical Engineering.
Expert Insights on Retinal Vascular Diseases
Study leader Professor Sharon Gerecht said: "Retinal vascular diseases affect millions of people, but our understanding remains limited, hindering our ability to discover and develop new therapeutics. Using human stem cells, we generated the cells found in retinal blood vessels, paving the way for new therapeutic approaches."
Prof Gerecht explained that the retina is part of the central nervous system, with a blood barrier that rigorously regulates what enters and exits. While this barrier maintains health, it also presents challenges for treatment. She noted: "This barrier is formed by blood vessel tissue comprising a tight network of retinal endothelial cells, in concert with other specialised cells called pericytes and astrocytes."
Overcoming Supply Challenges
Currently, retinal endothelial cells are harvested from patients, making them costly and limited in availability. To broaden availability and lower expenses, the Gerecht laboratory sought to cultivate them from iPSCs—adult cells reprogrammed to revert to primitive versions that can develop into other cell types.
The research team obtained commercial iPSCs and used a protocol to encourage them into standard endothelial cells, then a specialised mixture of growth factors to induce retinal-specific cells. Study first co-author Parker Esswein, a PhD student, said: "When this specialised blood vessel tissue begins to break down, it can cause many different diseases that lead to vision loss. Being able to grow a continuous supply from scratch could offer many advantages."
Rigorous Testing and Promising Results
The researchers subjected their creations to rigorous testing, successfully encouraging the cells to form networks and structures like those in the body. They exposed the tissues to reduced oxygen and elevated glucose levels—conditions that trigger diabetic retinopathy, the primary cause of vision loss in working-age Americans—and observed barrier deterioration mirroring patient responses.
When administered to mouse models with fragile retinal blood vessels, the lab-grown cells merged with existing tissue and helped develop robust blood vessels with resilient barriers. Mr Esswein said: "The tests showed that these lab-grown cells have promise for preventative treatments, especially since they should be easier and cheaper to obtain using our technique."
Future Applications and Industry Partnerships
The research team is now investigating potential applications for their retinal endothelial cells, both in their laboratory and through emerging industry partnerships. The group has a patent pending covering stem cell-based therapeutics and in vitro modelling for drug discovery and testing.
Mr Esswein added: "While our benchtop experiments did not attempt to model a wide variety of specific eye diseases in these studies, we're confident we can create excellent human tissue models in the lab to help better understand these diseases and uncover therapies."
