How safe is ESK transplantation?
Despite the many animal studies conducted over the past 30 years on embryonic stem cell therapy (ESC), the safety and effectiveness of this method has not yet been evaluated in clinical studies.
Since 1998, when human embryonic stem cell cultures (CESCS) were first obtained, they have been considered a potential source of cells suitable for therapeutic use.
However, experts have expressed concerns that some of these cells, even after differentiation into mature cells of various tissues, may retain the ability to almost infinite self-renewal and the formation of any body tissues, which leads to the formation of tumors (teratomas).
Another potential serious problem is the rejection of transplanted cells by the patient's immune system. Therefore, the researchers of Advanced Cell Technology decided first of all to analyze the effectiveness of transplantation of human ESCs (CESCS) differentiated into retinal cells into immunoprivileged human eye tissues that are not capable of developing a strong immune response.
As part of two clinical studies conducted under the supervision of Professor Robert Lanza, who is the head of the scientific department of Advanced Cell Technology, retinal cells grown from cESC were transplanted into 18 patients with severe visual impairments. Nine of them were diagnosed with atopic age–related macular degeneration, and the remaining nine were diagnosed with Stargardt macular dystrophy. Ultimately, both of these currently incurable diseases lead to complete blindness.
50,000, 100,000 or 150,000 retinal pigment epithelial cells obtained from the cESC were injected into each of the participants under the retina of the most affected eye.
During the follow–up period, the median of which was 22 months, and the maximum duration was 37 months, no adverse reactions associated with cESC were registered in patients. All reported side effects were caused by surgery or immunosuppression.
Moreover, during the first year after the procedure, an increase in the intensity of subcutaneous pigmentation was observed in 13 (72%) patients. At the same time, in 8 patients, the visual acuity of the operated eye increased by 15 letters and in 7 more – remained at the same level or slightly improved. At the same time, one patient's visual acuity decreased by more than 10 letters.
In general, the procedure significantly improved the vision of 10 of the 18 operated eyes, while the vision of the intact eyes of the same patients did not improve.
According to the authors, there is still a lot of work to be done before the methods of treatment with pluripotent stem cells pass all the necessary stages of clinical research for implementation into practice, but the first step in this direction has already been taken.
Article by Steven D Schwartz et al. 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 published in The Lancet.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Advanced Cell Technology:
ACT Announces Positive Results from Two Clinical Trials Published in The Lancet Using Differentiated
Stem Cell-Derived Retinal Pigment Epithelium (RPE) Cells for the Treatment of Macular Degeneration.
17.10.2014