Research continues to shine light on canine retinal disease

Canine retinas affected by three different diseases show how a marker of cell division (red) and rod cells (green) colocalize.

Historically, early retinal degeneration (ERD), an inherited canine retinal disease that leaves dogs sightless within a year of birth, was attributed to the eye’s inability to regenerate its photoreceptor cells, rods, and cones.

However, researchers from the University of Pennsylvania offered early evidence that photoreceptors can, in fact, regenerate. Now, they have expanded that research to include two other forms of canine blindness, and show that retinal cells continue to differentiate early in a dog’s life before overwhelming cell death caused the retina to degenerate.

The study was published March 11 in BMC Genomics.

The researchers examined two early-onset blinding diseases: X-linked progressive retinal atrophy, or xlpra2, and rod cone dysplasia 1, or rcd1. The team wanted to know whether retinal cells were proliferating and, if they were, what specific types of cells were doing so.

Using chemical markers that label cells going through division, along with markers that only tag rod cells, the primary photoreceptor retina, the researchers observed a period of cell proliferation.

The timing of this cell proliferation differed between the diseases. While ERD cells had entered a proliferation stage at seven weeks, the researchers observed similar increases in cell division at two weeks in rcd1 and at eight weeks in xlrpa2, all time points that precede or coincide with the known peaks of cell death in the three diseases.

“If you have a cell that is functional but sick, perhaps we could provide it with some agent that will allow it to keep replenishing itself and maintain a functional retina for a longer period of time,” said Gustavo D. Aguirre, VMD, PhD, and one of the study authors.

Photo credit: University of Pennsylvania

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