New research has been carried out – file image (Image: Getty)
Blind people have been given renewed hope of regaining their sight after laboratory-cultivated cells restored retinal function in mice.
The advancement demonstrates potential for novel eye treatments, according to American scientists.
Biomedical engineers at Duke University, 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 the 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.
They state their findings, published in the journal Nature Biomedical Engineering, indicate the potential of employing the retinal cells and models to develop new methods of significant vision loss treatments and eye disorder research.
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.”
She states the old saying that the eyes are “windows into the soul” is more accurate than people might think. Prof Gerecht explained that neurons from the retina – the rear section of the eye responsible for detecting light – extend directly to the brain, technically rendering the eyes part of the central nervous system.
Much like the brain itself, the retina possesses a blood barrier that rigorously regulates what enters and exits, including oxygen, nutrients, water – and pharmaceutical compounds.
While the barrier maintains the retina’s health and offers relative protection from disease-causing agents, Prof Gerecht notes it also presents significant challenges when attempting to treat the retina.
She said: “This barrier is formed by blood vessel tissue comprising a tight network of retinal endothelial cells, which form the inner layer of blood vessels, in concert with other specialised cells called pericytes and astrocytes.
Scientist looking into microscope – file image (Image: Solskin via Getty Images)
“The specificity of these cells and the fact that they do not form in other areas of the body make the complex tissue difficult to heal or to grow from scratch.”
Study first co-author Parker Esswein, a PhD student working in the Gerecht lab, said: “When this specialised blood vessel tissue begins to break down, it can cause a lot of different diseases that lead to vision loss.
“While there are sources of retinal endothelial cells, being able to grow a continuous supply from scratch could offer many advantages for those working in the field.”
The retinal endothelial cells are presently harvested and cultivated from actual patients, rendering them comparatively costly with limited availability. To broaden availability, lower expenses and manage inconsistency, the Gerecht laboratory sought to determine whether they could cultivate them from iPSCs – developed adult cells reprogrammed to revert to primitive versions of themselves that can subsequently develop into a diverse range of other cell types.
The research team obtained commercial iPSCs and employed a well-established protocol to encourage them to develop into standard endothelial cells that constitute the inner lining of most of the body’s blood vessels.
The researchers then utilised a specialised mixture of growth factors to encourage the cells into becoming the particular type of endothelial cells present in the retina.
Following success, the researchers subjected their new creations to rigorous testing.
In experiments, the team successfully encouraged the cells to form the same networks and structures that they establish within the body.
The researchers then exposed the laboratory-grown tissues to reduced oxygen and elevated glucose levels, which are harmful conditions frequently observed in actual people.
The team explained that the conditions are “fundamental” triggers of diabetic retinopathy, the primary cause of vision loss in working-age individuals in the United States, and prompted the tissue barrier to deteriorate precisely as it does in patients.
This image depicts deteriorated human retinal endothelial cells, which are essential for maintaining eye sight. (Image: SWNS)
The researchers then tested their laboratory-grown cells as a treatment for mouse models with fragile, poorly structured retinal blood vessels. When administered to the mice prior to any actual deterioration of vision, the cells successfully merged with the existing tissue and aided in the development of 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.”
He 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.”
The research team is now looking to investigate potential applications for their retinal endothelial cells, both within their laboratory setting and through emerging industry partnerships.
The group also has a patent pending that covers both the stem cell-based therapeutics and in vitro modelling for drug discovery and testing.
