Ophthalmology, Research

New eye models allow for better drug development

A newly detailed model for cultivating retinal pigment cells could make the development of new and improved ocular drugs significantly easier.

Developed by researchers from the University of Eastern Finland, the new model allows for cultivated retinal pigment epithelial cell lines to feature both pigmentation and a blood-retinal barrier. These qualities provide a much more accurate representation of the back of the eye, allowing for new drugs to be more thoroughly tested.

Drugs tend to bind to cellular pigment and, consequently, accumulate in the retinal pigment epithelium (RPE). Not only does the new model allow this effect to be studied in more detail, but non-pigmented RPE cells can also be re-pigmented by feeding them melanin.

This lets the rate at which drugs bind to melanin to be compared between samples.

“By using non-pigmented cells as controls, we were able to study how much of a drug given to the cells eventually ends up in the melanosomes,” Dr Mika Reinisalo, from the University of Eastern Finland, said.

“Next, we need to find out for how long the melanosomes can hold on to a drug, and whether this causes any harm. The accumulation of drugs in the melanosomes can, on the other hand, make it possible to target drugs at specific tissues.”

This adds to another model detailed by the University of Eastern Finland earlier this year that features a more realistic blood-retinal barrier than current models.

As the blood-retinal barrier affects both the entry and exit of drugs from the eye, simulating it is important in the early stages of drug development. In a study published in Pharmaceuticals earlier this year, the team identified a new RPE cell population that forms a layer that resembles the epithelial layer of the eye.

“We named this cell population after its discoverer, Senior Laboratory Technician Lea Pirskanen, who is also one of the authors of the study,” Dr Laura Hellinen, from the University of Eastern Finland, said.

“These cells are now known as LEPI cells. We decided to study them in more detail and discovered that in comparison to earlier cell models, LEPI cells are better differentiated and they form a tighter and more realistic barrier through which drugs have to pass.”

It is hoped the new models will allow for a reduction in the need for animal testing.