Cell-based therapies, primarily using stem cells, represent a second powerful, mutation-agnostic treatment avenue for Retinitis Pigmentosa that holds the potential for both slowing degeneration and facilitating functional replacement. Researchers are investigating multiple types of stem cells, including induced pluripotent stem cells (iPSCs), embryonic stem cells, and adult stem cells (such as those derived from bone marrow), for their capacity to address the disease.

The initial strategy focused on the neurotrophic potential of stem cells, where the transplanted cells act as "nurse cells" by secreting protective growth factors and anti-inflammatory substances that support the survival of the patient's remaining photoreceptors. This approach aims to slow the progression of vision loss rather than restoring vision. Clinical investigations into this mechanism, including trials using bone marrow-derived CD34+ stem cells, are a significant component of the advanced cell therapy segment for ophthalmic conditions.

The long-term and more complex goal involves true cell replacement, where stem cells are differentiated in vitro into new photoreceptors or retinal pigment epithelial (RPE) cells and transplanted into the retina to replace the cells that have already died. This technically demanding procedure aims for functional integration of the new cells into the existing neural circuitry. While challenging, the successful integration of lab-grown retinal tissue into animal models provides a blueprint for future human trials seeking to restore vision in patients with severe degeneration.

FAQ

• How do stem cells help RP patients? They are thought to help by secreting protective factors to save remaining retinal cells, or, in more advanced research, by replacing the lost photoreceptor and RPE cells.

• Are stem cell treatments for RP regulated? Highly regulated clinical trials are ongoing, but patients should be cautious of unlicensed, unproven, and fee-for-service stem cell clinics which can pose significant risks.