For release: Wednesday, January 9, 2002A new study shows that mouse embryonic stem cells transplanted into rats with brain damage resembling Parkinson's disease spontaneously acquire many of the features of dopamine-producing neurons. Animals that received the transplants showed a gradual reduction in their parkinsonian symptoms, and brain scans revealed evidence that the transplanted cells integrated with the surrounding area and began to produce dopamine. The findings raise the possibility that embryonic stem cell transplants may one day be useful in treating Parkinson's disease and other brain disorders.
Many of the symptoms of Parkinson's disease result from the loss of neurons that produce dopamine, a nerve-signaling chemical. Previous studies have shown that embryonic stem cells can take on the characteristics of dopamine-producing neurons in culture. However, this is the first study to show that undifferentiated (unspecialized) embryonic stem cells transplanted into the brains of an animal model for Parkinson's disease can develop into dopamine-producing cells with no special pre-treatment to control their fate. The study was carried out by Dr. Ole Isacson of McLean Hospital and Harvard Medical School in Belmont, Massachusetts, and colleagues. It appears in the January 8, 2002, early edition of the Proceedings of the National Academy of Sciences and was supported by the National Institute of Neurological Disorders and Stroke (NINDS).
While the results of this study are intriguing, they also reveal the need for additional research. The transplanted cells did not survive in 6 of the 25 rats treated, and 5 of the animals developed tumors near the site of the transplants within the first 9 weeks. These complications illustrate the importance of learning how to control the differentiation and proliferation of stem cells before planning similar therapies in humans. Researchers still need to learn how the stem cells develop into dopamine-producing cells and identify genes and chemical signals that control this process. This information should help researchers learn to control the cells in ways that improve their effectiveness and reduce the risk of tumors and other side effects.
Reference: Bjorklund, LM; Sanchez-Pernaute, R; Chung S, et. al. "Embryonic stem cells develop into functional dopaminergic neurons after transplantation in a Parkinson rat model." Proceedings of the National Academy of Sciences, January 8, 2002, early edition.
- By Natalie Frazin
Last Modified February 1, 2016