The time of stem cells is approaching
For more than 10 years, stem cell therapy has been presented as a hope for a cure from severe genetic and degenerative diseases. The data released at the X Congress of the International Society for Stem Cell Research (ISSR), held on June 13-16 in Yokohama, Japan, made these promises one step closer to reality.
One of the works that attracted the attention of specialists was the initial clinical study conducted by specialists of StemCells, Newark, California, of the method of using human neural stem cells for the treatment of sudanophilic leukodystrophy (Peliceus-Merzbacher disease), the cause of which is a mutation that suppresses the formation of myelin, a protective material covering the nerve fibers of the brain. Patients from infancy suffer from progressive movement coordination disorders and other neurological symptoms. To date, this disease is incurable.
The company has created a bank of highly purified neural stem cells isolated from the nervous tissue of adults. When injected into rodents, these cells did not form tumors, but migrated into brain tissues and differentiated into various types of nerve cells, including cells synthesizing myelin protecting nerve fibers. (On RIKEN CDB; StemCells Inc
At the end of the animal experiments, the company funded an initial clinical trial of the safety of the method, in which four infants with Peliceus-Merzbacher disease were transplanted 75 million nerve stem cells into each of the four injection sites. After that, patients were prescribed immunosuppressive therapy to prevent rejection of donor cells. During the study, there were no questions related to the safety of therapy. Moreover, magnetic resonance imaging performed 18 months after the procedure demonstrated the formation of myelin sheaths around axons, while clinical observations indicated a moderate improvement or preservation of motor functions at the initial level.
The firm is currently planning to conduct more large-scale clinical trials. According to Ann Tsukamoto, the company's deputy director for research, if the effectiveness of experimental therapy is proven, it can form the basis of new treatments for multiple sclerosis, cerebral palsy and Alzheimer's disease.
The results of the second promising work were presented at the congress by Masayo Takahashi, a researcher at the Japanese Center for Developmental Biology RIKEN. She published the results of a preclinical study aimed at developing cell therapy for age-related macular degeneration of the "wet type". With this disease, the cells of the retinal pigment epithelium that support the vital activity of the photosensitive cells of the eye die off, and the growth of abnormal "flowing" blood vessels under the retina. The result is deterioration and subsequent loss of central vision.
The researchers developed a strategy consisting in surgical removal of pathologically altered blood vessels and replacement of damaged retinal pigment epithelial cells with new cells grown from the patient's own cells. Using the method of cell reprogramming, scientists transform the patient's skin cells into so-called induced pluripotent stem cells (iPSCs), capable of differentiating into all types of cells in the human body. After that, they transform the obtained iPSCs into retinal pigment epithelial cells, from which cell layers are formed in the laboratory for subsequent transplantation. The use of the patient's own cells in the application of this approach eliminates the need for immunosuppressive therapy.
The therapeutic cells grown by the researchers demonstrate the structure and profile of gene expression characteristic of human retinal pigment epithelium cells. The introduction of such cells to mice did not lead to the formation of tumors. When injected into monkeys, the cells remained viable for more than 6 months. The researchers have not tested the ability of this procedure to improve the vision of animals, however, they note that there is evidence according to which the transplantation of own pigment epithelial cells isolated from the peripheral regions of the retina into the pathologically altered central area of the retina significantly improves the vision of patients. They hope to get all the necessary permits to conduct clinical trials within a year.
Earlier this year, scientists from the University of California at Los Angeles and Advanced Cell Technology (Marlborough, Massachusetts) published data on the safe and effective use of retinal pigment epithelial cells derived from human embryonic stem cells to treat another type of macular degeneration in a small number of patients. Based on this and his own data, Takagashi suggests that in the future the choice of a particular type of stem cells for therapeutic purposes will depend only on the disease and the special conditions in which the patient is located.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Science NOW: Stem Cells Move Into Prime Time.
19.06.2012