Analysis of the brain of a patient suffering from Parkinson's Disease has shown that the experimental treatment he received caused regrowth of the nerve fibres that are lost in this disease. The findings are reported in the July issue of Nature Medicine.
This is the first time that any treatment has been shown to reverse the loss of nerve fibres in Parkinson's Disease.
The 62-year-old man was one of five patients in a pilot study carried out by Mr Steven Gill at Frenchay Hospital in Bristol, UK. In this study, an experimental drug (GDNF) was pumped through a fine catheter into a damaged part of the brain. Within a couple of months, patients were noticing dramatic improvements in their ability to move, and these continued over almost four years of treatment. Even after ceasing medication, the patients' improvement has been maintained.
After the death of the 62-year-old patient from a heart attack, Professor Seth Love from Bristol University was able to examine his brain. Because the GDNF had been infused into one side of the brain only, the effects of the treatment could be assessed by comparing the two sides.
In Parkinson's Disease, nerves containing the chemical messenger dopamine are lost from a region of the brain region known as the putamen, leading to tremors and other motor abnormalities characteristic of the disease.
Professor Love found that dopamine-containing nerve fibres had sprouted back in the putamen. He said: "This is the first neuropathological evidence that infusion of GDNF in humans causes sprouting of dopamine fibres, in association with a reduction in the severity of Parkinson's Disease." The findings may revitalise interest in GDNF administration as a potential therapy for this degenerative condition, providing renewed hope for patients disappointed by the recent withdrawal of this drug due to concerns about its safety.
GDNF, which stands for glial cell line-derived neurotrophic factor, is a natural growth agent needed by brain cells to produce dopamine, which transmits impulses between certain nerve cells including those that regulate movement. A reduced concentration of dopamine in the brain is associated with Parkinson's Disease.