Stem cell secretions protect retina

A study of rats suggests that stem cell secretions, or exosomes, could play a role in protecting the retina.

Researchers at the National Eye Institute isolated exosomes from bone marrow stem cells and performed weekly injections of the stem cell secretions into the rats’ vitreous.

The exosomes were fluorescently labelled before the injection so their delivery to retinal ganglion cells could be tracked.

Following an optic nerve injury, rats that were treated with exosomes lost a third of their retinal ganglion cells, compared to a 90% loss among untreated rats.

Retinal ganglion cells are found in the optic nerve and carry visual information from the eye to the brain. The death of these cells leads to vision loss in glaucoma.

National Eye Institute post-doctoral fellow, Dr Ben Mead, explained to OT that the loss of retinal ganglion cells (RGC) was the leading cause of irreversible blindness.

“Currently no treatment exists that directly protects RGC from death and following their loss, the RGC cannot be replaced,” he added.

Stem cells, which can change into any cell within the body, have been the focus of attempts to replace and repair tissues.

However, Dr Mead explained that transplantation of whole stem cells into the eyes of patients had various risks and a significant cost.

Unlike stem cells, exosomes were highly stable and did not suffer from the risk of unwanted migration and proliferation, he explained.

“This research suggests that large numbers of exosomes could be purified and stored as an off-the-shelf drug, attaining similar therapeutic efficacy but in a cell-free manner,” Dr Mead added.