| Parkinson's disease (PD) is a degenerative disorder | | | | and led to functional recovery in eight of nine rats. |
| affecting the central nerve system. A person with | | | | Importantly, no cancers that might have been caused |
| Parkinson's disease may develop muscular rigidity, | | | | by the transplants were detected up to eight weeks |
| tremors, and altered speech patterns. The person | | | | following transplantation. |
| may also have problems using language and lose | | | | An additional remarkable study was reported recently |
| higher cognitive functions. PD may cause a person to | | | | by Zhou et al.2 at the Harvard Stem Cell Institute. |
| move very slowly (bradykinesia) and may cause loss | | | | Using an in vivo approach in adult mice, this team |
| of balance. The disease is progressive and chronic. PD | | | | directly converted mouse pancreatic exocrine cells |
| is not fatal, but eventually severe muscular problems | | | | into pancreatic endocrine β-cells. The team used |
| may cause pneumonia, choking, and falls which may | | | | an adenovirus to transfect the exocrine cells with a |
| result in death. PD affects approximately 150 out of | | | | specific combination of transcription factors, |
| every 100,000 Caucasian individuals, and is slightly less | | | | effectively reprogramming the exocrine cells into |
| prevalent among African-Americans. | | | | endocrine β-cells. This stunning breakthrough |
| Parkinson's disease is caused by decreased activity of | | | | demonstrates that it is possible in certain |
| dopamine (DA)-secreting nerve cells located in the | | | | circumstances to avoid the necessity of |
| substantia nigra ("black substance") of the brain. DA is | | | | reprogramming a cell to an embryonic pluripotent |
| a neurotransmitter involved in the regulation of | | | | state. Zhou et al showed that transdifferentiation is |
| muscular activity as well as various neuropsychiatric | | | | possible by using a cocktail of lineage-specific |
| functions including cognition and behavior. A common | | | | transcription factors. |
| medical treatment for PD is L-Dopa which is | | | | Much work is needed to be done, of course. Yet the |
| converted into DA by dopaminergic neurons in the | | | | work of both these research teams points to |
| substantia nigra. Administration of L-Dopa attempts | | | | exciting new possibilities for treatment of these |
| to replace the body's supply of DA. The drug is not | | | | devastating diseases. |
| an optimal therapy - only a small percentage is | | | | The field of regenerative medicine is progressing at |
| converted to DA and the drug causes many | | | | an astonishing rate. Hallowed concepts of embryology |
| side-effects. | | | | and development are being revised, practically |
| PD is an ideal candidate for stem cell treatment. | | | | on-the-fly, yearly if not monthly. We are living in very |
| Brilliant research by Wernig et al.1 (conducted in the | | | | exciting times. |
| Jaenisch laboratory at the Whitehead Institute for | | | | 1 Wernig M, et al: Neurons derived from |
| Biomedical Research) demonstrated successful | | | | reprogrammed fibroblasts functionally integrate into |
| treatment of PD in adult rats using neurons derived | | | | the fetal brain and improve symptoms of rats with |
| from stem cells. These authors derived iPS cells by | | | | Parkinson's disease. Proc Natl Acad Sci USA |
| reprogramming rat connective tissue cells. The stem | | | | 105(15):5856-5861, 2008 |
| cells were then transformed into neuronal cell types | | | | 2 Zhou Q, et al: In vivo reprogramming of adult |
| and transplanted into the brains of adult rat models | | | | pancreatic exocrine cells to beta-cells. |
| of PD. The nerve cells were successfully transplanted | | | | |