Stem cells against Parkinsonism: work continues
The idea of treating Parkinson's disease with cell therapy is not new. One of the key manifestations of this age-related disease is the death of dopaminergic neurons in the brain. Theoretically, the replacement of dying cells should provide a significant improvement in the patient's condition.
In an adult, the region of the brain known as the black substance contains about half a million dopaminergic cells. The death of half of them leads to the appearance of symptoms of Parkinsonism, such as tremor (trembling) of the limbs at rest, lethargy and stiffness of movements.
Over the past three decades, researchers have made a number of attempts to replace dead dopaminergic neurons with fetal cells isolated from aborted embryos. In addition to serious ethical issues, this approach is impractical, since it cannot provide enough cellular material for all patients who need such therapy.
Moreover, the conducted studies have brought contradictory results. Some patients showed significant improvements that persisted for 15 years. At the same time, in some cases, therapy not only did not bring relief, but also caused serious side effects. This was partly due to differences in experimental protocols, for example, the age of patients, the number of transplanted cells and the methods used for this.
Professor Roger Barker from the University of Cambridge assures that the protocol developed by him in collaboration with European colleagues will overcome all the barriers standing in the way of developing an effective and safe method of cell therapy for Parkinson's disease.
The key feature of the new approach is that it provides highly targeted reprogramming of neural progenitor cells derived from fetal stem cells into dopaminergic cells of the substantia nigra. This will avoid the appearance of neurons of various types in the transplantation zone and the formation of unnecessary tissue formations.
Preclinical studies of the new approach on a mouse model of Parkinson's disease have shown promising results. However, observations of mice have been carried out for several months, whereas Parkinson's disease has been progressing for decades. Moreover, the study of postmortem preparations of the brain tissue of patients who underwent fetal cell transplantation, in some cases, showed the presence of a disease-associated protein in the transplant cells. However, according to Professor Barker, even if this is true and the disease eventually affects donor cells, therapy can give a person more than one decade of healthy life.
Currently, a preliminary clinical trial of a new approach to the treatment of Parkinson's disease with fetal cells is planned in Europe according to a protocol developed under the guidance of Barker. If successful, by 2018, experts plan to launch a number of similar clinical trials in Europe, the USA and Japan using dopaminergic cells derived from embryonic stem cells. In addition, Japanese colleagues hope to conduct a similar study using induced pluripotent stem cells (iPSCs) obtained by reprogramming from the skin cells of the patients themselves.
At the same time, Barker notes that, most likely, cell therapy will not completely cure Parkinson's disease and will not be more effective than existing drug approaches. He also notes that for its widespread introduction into clinical practice, it is necessary to reduce the cost of the process of working with cells.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of Cambridge: Taking a shot at Parkinson's.
17.10.2014