Synthetic Form of Active Marijuana Ingredient Preserves Vision in Rats with RP

February 12, 2014

A highly potent synthetic form of THC, the substance in marijuana that produces a high for users, has shown strong vision-preserving effects in rats with a form of autosomal dominant retinitis pigmentosa (adRP). Rats with adRP that were injected with the synthetic THC known as HU210 had 40 percent more rows of photoreceptors and 70 percent greater retinal sensitivity than untreated rats. The treatment also protected the connections between photoreceptors and other cells in the retina. Results of the investigation were published in the journal Experimental Eye Research.

The study’s lead investigator, Nicolás Cuenca, Ph.D., at the University of Alicante in Spain, says that HU210, in other studies, has protected neural cells in a variety of brain and neurological conditions, including ischemic stroke and Alzheimer’s and Parkinson’s diseases. Marijuana derivatives, known as cannabinoids, can also reduce intraocular pressure, which can lead to glaucoma, a condition that causes vision-robbing damage to the optic nerve.

Because HU210 is 100 times more potent than the THC found in marijuana, it would likely need to be formulated as an eye drop for use as a retinal disease treatment. “Systemic administration of HU210 would not be feasible because of its strong mood-altering effects,” says Dr. Cuenca. He cautions that much more research needs to be done on HU210 before it can be evaluated as a retinal therapy in humans.

The rats in the study had P23H mutations in the RHO gene, which accounts for about 12 percent of adRP in humans. Dr Cuenca says that the anti-oxidant and anti-inflammatory properties of HU210 might make it beneficial for the treatment of other retinal conditions, but again, more research is needed.