Lead author Shaomei Wang of Cedars-Sinai said that this is the first study to show preservation of vision after a single injection of adult-derived human cells into a rat model with age-related macular degeneration.
The stem cell injection resulted in 130 days of preserved vision in laboratory rats, which roughly equates to 16 years in humans.
Age-related macular degeneration affects upward of 15 million Americans. It occurs when the small central portion of the retina, known as the macula, deteriorates. The retina is the light-sensing nerve tissue at the back of the eye. Macular degeneration may also be caused by environmental factors, aging and a genetic predisposition.
When animal models with macular degeneration were injected with induced neural progenitor stem cells, which derive from the more commonly known induced pluripotent stem cells, healthy cells began to migrate around the retina and formed a protective layer. This protective layer prevented ongoing degeneration of the vital retinal cells responsible for vision.
Researchers first converted adult human skin cells into powerful induced pluripotent stem cells (iPSC), which can be expanded indefinitely, and then made into any cell of the human body. In this study, these induced pluripotent stem cells were then directed toward a neural progenitor cell fate, known as induced neural progenitor stem cells, or iNPCs.
Researcher Clive Svendsen said that these induced neural progenitor stem cells are a novel source of adult-derived cells which should have powerful effects on slowing down vision loss associated with macular degeneration, adding that though additional pre-clinical data is needed, their institute is close to a time when they can offer adult stem cells as a promising source for personalized therapies for this and other human diseases.
Next steps include testing the efficacy and safety of the stem cell injection in preclinical animal studies to provide information for applying for an investigational new drug. From there, clinical trials will be designed to test potential benefit in patients with later-stage age-related macular degeneration.