Parkinson's brain implant

Brain implant delivers drugs directly through head

Image credit: MintMotion for Passionate Productions/PA Wire

In a pioneering study, patients with Parkinson’s disease have been fitted with implants to deliver drugs directly to the brain through the side of the head.

The trial is part of a Parkinson’s UK-funded study carried out in association with the North Bristol NHS Trust.

The implants were fitted in 41 patients via robotic surgery, which involved placing four tubes in the brain. The device sends a naturally occurring protein – Glial Cell Line Derived Neurotrophic Factor (GDNF) – through a port in the side of the head directly to the affected part of the brain; scientists hope that this could restore cells damaged by the disease. Delivering the protein in this manner allows for it to be infused with “pinpoint” accuracy.

For the first nine months of the trial, half of the patients received monthly infusions of GDNF, while the others received a placebo.

Brain scans of the patients who received the GDNF showed signs of improvement after the initial nine months, researchers have reported in Brain and the Journal of Parkinson’s Disease. While the patients had been diagnosed on average eight years before the trial, the scans showed brains that appeared more like those of patients just two years after their diagnosis; an improvement unlike anything seen in similar trials.

Follow the initial stage of the trial – after which all patients showed some improvement in symptoms – all patients were offered nine months of GNDF treatment. After the full 18 months, both groups showed moderate to large improvements in their symptoms, with some able to take up activities such as cycling.

“We’re shown with the PET scans that having arrived, the drug then engages with its target, dopamine nerve endings, and appears to help damaged cells regenerate or have a biological response,” said principal investigator Dr Alan Whone. Whone says that it is uncertain whether the observed improvement is due to the placebo effect or due to the efficacy of the treatment, and some questions remain about the effect of dose and early intervention.

However, the effectiveness of the delivery system itself could offer new options for treating brain tumours, strokes and other neurological conditions. This was the first trial in which the implant was used.

“This trial has shown that we can safely and repeatedly infuse drugs directly into patient’s brains over months or years through a small implanted port that emerges through the skin behind the ear,” said Professor Steven Gill, the neurosurgeon who designed the implant. “This is a significant breakthrough in our ability to treat neurological conditions such as Parkinson’s because most drugs that might work cannot cross from the bloodstream into the brain due to a natural protective barrier.”

Gill hopes that the system could be used to administer chemotherapy drugs to patients with brain tumours, or to test new drugs for patients with neurodegenerative disorders.

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