How we study the corneal endothelium in the laboratory

17/11/2026

Understanding the behaviour of the endothelium is key to developing future therapies that protect corneal transparency.

The cornea consists of three main layers: the epithelial cells (the outermost layer), the stroma (the thickest layer) and the endothelium (consisting of a single layer of hexagonal cells, known as corneal endothelial cells or CECs). CECs act as a barrier and pump water into the aqueous humour, thereby preventing corneal oedema.

Despite their essential function, under normal conditions inside the eye, these cells do not divide. Furthermore, their number decreases with age, and certain diseases or injuries can reduce their numbers to levels that cause blindness. This is why the number of CECs is one of the main criteria used to assess the quality of donor corneas.

Interestingly, although they do not divide, CECs can increase in size to cover the spaces previously occupied by cells that have died. To understand how the corneal endothelium behaves and how we might one day restore its function, researchers use several complementary laboratory models.

The most direct approach involves using donor corneas, which allow researchers to observe real human tissue and measure how CECs respond to stress, ageing or disease. However, these samples are limited, so cell cultures are also used. By culturing CECs, researchers can study how different growth factors, substances or environments influence the endothelium's ability to repair itself.

Scientists also use animal models, which help reveal how CECs interact with other tissues and how diseases develop. More recently, advances in bioengineering have made it possible to develop artificial corneal tissues. These models mimic human physiology and allow researchers to recreate diseases and test potential therapies without relying solely on donor tissue.

Together, these approaches help us understand the behaviour of the endothelium and how we might stimulate its repair when necessary, for example in corneal dystrophies such as Fuchs' dystrophy or in corneal transplantation.

Justin Christopher D’Antin, Experimental Research Coordinator at the Barraquer Ophthalmology Centre