Researchers at the Universidad de Oviedo, Spain, has reported a systematic review and analysis on stem cell treatments for a range of retinal degenerative disease. In many retinal disorders, there are limited surgical and pharmacological options available aiming to regenerate retinal tissues however, there is significant research in progress on the global stage. Current estimates for affected AMD patients number 196 million people worldwide, while RP patients are estimated to have 2.5 million. Consequently, novel stem cell technologies may provide valuable opportunities to address these challenging disorders.
The research team at the Universidad de Oviedo has now collated research data, up to September 2021, searching for just under 1,300 publications and assessing almost 70 clinical trial studies aiming to address stem cell treatments for retinal degenerative diseases. From the analysis on the clinical studies conducted, the majority of the research treatments were underway in AMD, retinitis pigmentosa and Stargardt’s Macular Dystrophy and this may support significant hope to build further opportunities in the coming decade.
Commenting on their paper, the authors commented that, “[i]n the next few years, we expect to see quantifiable results in terms of visual function improvement. The use of stem cells in eye regeneration is slowly becoming positioned as an exciting retinal strategy for treating degenerative diseases. However, there is still a need for more in-depth research to increase our understanding of the mechanisms underlying stem cell differentiation into the different retinal neuronal phenotypes and to develop techniques to achieve synaptic integration and circuitry functional restoration”.
According to their research, the majority of the clinical trials studied were related to the degenerative loss of photoreceptors and/or RPE cells, such as for studies on AMD (33%), RP (24%), or Stargardt disease (12%). In their summary of findings of the analysis of 69 clinical trials using human stem cells for transplantation into diseased human retina, a total of 58.3% of the trials (35 out of 60) used cells “from extraocular sources, with autologous bone marrow stem cells being the cell type preferred to prepare the transplantation product (in 26 cases), followed by mesenchymal stem cells of umbilical cord origin”. Further, the researchers commented that the use of neuronal cells to repair retinal degeneration may be the optimal appropriate strategy, due to the similarity between transplanted cells and the degenerated retinal neurons. In addition, their study indicated that one of “the best-known stem cell therapies in retinal disease is ‘photoreceptor replacement therapy’”, and this may be used in various retinopathies for the restoration of visual function. Regardless, the future on this clinical horizon for stem cell research treatments should be hugely optimistic.