In 2020, a chance discovery of microscopic structures in the retina that control blood flow was the launching pad for Dr Luis Alarcon-Martinez’s current research towards a potential new treatment for glaucoma.

“Blood flow is very important for the retina, the optic nerve and the brain,” says Dr Alarcon-Martinez, Head of Visual Neurovascular Research at CERA.

“If you stop blood flow, nerve cells will die, and nerve cells are what are damaged in glaucoma.

“These structures that control blood flow, which we have only discovered recently, might play a very important role in how we treat diseases like glaucoma.”

Three years after being part of the team that discovered these structures, alongside Professor Adriana Di Polo at the University of Montreal, Dr Alarcon-Martinez is now looking to see how these might play a role in glaucoma.

“Thanks to a five-year grant from Fighting Blindness Canada, we’ve brought together international expertise in different aspects of glaucoma in a study that will hopefully pave the way toward new treatments,” says Dr Alarcon-Martinez.

Adventure of curiosity

Nerve cells in the retina, optic nerve and brain are all affected in glaucoma.

Nerve cells need a constant flow of oxygen and nutrients from blood vessels to work properly.

This flow of energy is regulated by another type of cell called a pericyte, which wraps around blood vessels and controls how much blood passes through them.

By looking at a living organism in high resolution, Dr Alarcon-Martinez and Professor Di Polo discovered pericytes project microscopic structures, called nanotubes, that send signals between blood vessels to direct blood where it is needed.

When these nanotubes are damaged, this communication breaks down and blood stops flowing correctly.

“The discovery of these tunnelling nanotubes was completely serendipitous – we were observing the retina and seeing these very thin connections between pericytes and capillaries,” says Professor Di Polo.

“It was an adventure of curiosity to find out how these nanotubes communicate, how they change blood flow and, importantly, how they are affected in diseases.”

Future progress

A team of leading experts is now investigating exactly how these nanotubes break, and if it could be a factor in glaucoma.

The team will use a two-photon microscopy setup based at WEHI to look at the health of nanotubes in the retina, the optic nerve head and the brain in very high resolution.

As well as Dr Alarcon-Martinez and Professor Di Polo, University of Melbourne Professor of Optometry and Vision Sciences Bang Bui will be providing a model of glaucoma that the team will use to compare to healthy examples.

“The model allows us to raise eye pressure and put it back to normal at any given time to answer whether nanotubes repair themselves,” says Professor Bui.

“We’re effectively seeing if we could potentially make a difference in their function if we intervene early enough.”

Exciting potential

Professor Di Polo says she has very high hopes for the study.

“Our ultimate goal is a new type of therapy that protects the function of nanotubes in regulating blood flow to the complex network of nerve cells from the retina to the brain.”

Dr Alarcon-Martinez says the project could potentially have an impact on research into any disease that is affected by blood flow, not just glaucoma.

“Diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration and even Alzheimer’s disease are all affected by blood flow.

“We’re excited to see where this project leads us.”

This story was originally published in People in focus: Annual Review 2023.