Stem cells can turn into all the different cell types of the body. It has been a goal of researchers to use this plasticity of stem cells to regenerate damaged organs and tissues. Last month an article published in The Lancet showed that human embryonic stem cells could help improve vision in patients with degenerative disorders that cause blindness.
The group of US scientists undertook clinical trials to assess safety, tolerability and effectiveness of transplanting retinal cells derived from embryonic stem cells in patients with: 1) “Stargardt disease”, which is an inherited disorder that causes retinal degeneration and eventually blindness in children and young adults and 2) age-related macular degeneration, which causes blindness in the older people. The follow up of the 18 patients (9 in each trial) was approximately two years. The trial found that transplanted human embryonic stem cell derived retinal cells did not multiply abnormally and did not cause any problems with rejection or adverse effects on the surrounding tissues. There were some side effects related to the surgical implantation of cells and immunosuppression. On average the patients’ vision improved, whilst the control group had no benefit.
This study demonstrated the first ever evidence of the medium-term to long-term safety, cell survival, and possible biological activity of stem cell progeny in individuals with any disease. The results suggest that human embryonic stem cell-derived cells may be a safe new source of cells and can be used for treatment of various unmet medical disorders.
The result show that no major adverse effects related to the cells after maximum 37 months duration of treatment. The trial concluded that the subretinal area is most suitable for such cell injections. The scientists suggest that retinal cells derived from embryonic cells should be used early in the treatment of retinal disease to give the patients a better chance for preservation of sight.
Lu, B., Malcuit, C. et al. (2009). Long-term safety and function of RPE from human embryonic stem cells in preclinical models of macular degeneration. Stem Cells 27 (9), 2126-2135.
Lund, R.D., Tezel, T.H. et al. (2006). Human embryonic stem cell-derived cells rescue visual function in dystrophic rats. Cloning and Stem Cells 8 (3), 189–199.
Schwartz, S.D., Regillo, S.D. et al., (2015). Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt’s macular dystrophy: follow-up of two open-label phase 1/2 studies. The Lancet 385 (9967), 509-516.