Stem Cell Tx for Retinal Disease
American Journal of Ophthalmology, July 2017
In a review-based perspective article, Rao et al. recommended that clinicians exercise caution when considering stem cell therapies for patients with retinal diseases. The authors emphasized that rigorous safety and efficacy analyses are lacking for these treatments and that federal regulations for trials involving stem cells may not be sufficiently stringent.
In theory, stem cell therapies may restore visual acuity in patients with age-related or inherited retinal degeneration. In practice, no patient has had improvement in visual acuity or retinal electrophysiology after transplantation of pluripotent fetal or adult stem cells. Autologous induced pluripotent stem cells (iPSCs), prepared from somatic cells, can be differentiated to yield retinal pigment epithelium with low immunogenicity. However, cancer-driver mutations may be incorporated during preparation of iPSCs, and the process of ensuring that cells are free of these mutations is a costly one. Presently, the aim of most stem cell therapies for retinal disease is to support survival of the patient’s existing retinal cells by trophic stimulation, not to replace these cells.
Approximately 30 trials of stem cell–based treatments for retinal diseases are listed at www.ClinicalTrials.gov, but no treatment has been approved by the U.S. Food and Drug Administration. Although the 21st Century Cures Act allows for expedited approval of certain regenerative techniques, this law may allow treatments to be approved before long-term safety or efficacy data are available. Currently, most trials involve transplanting adult stem cells, which may be harvested from nonocular sites such as bone marrow or adipose tissue. Preclinical results have shown adverse effects and no benefits of applying adipose-derived stem cells to treat retinal disease.
Despite the promise of these therapies and some early data suggesting acceptable safety profiles, serious complications have occurred, including hemorrhage, proliferative vitreoretinopathy, retinal detachment, and blindness. The authors concluded that ophthalmologists should use caution when considering stem cell interven- tions for patients with retinal disease.
The original article can be found here.