THE PARKINSONIAN

2

What is this new treatment?

Deep within the brain is a structure known as the choroid plexus,

which releases a natural mix of growth factors that make nerves

grow. These growth factors can also protect the brain from

injury and help repair damage.

It is impossible to transplant human choroid plexus cells.

However, Auckland Island Pig choroid plexus cells can be

transplanted. Earlier research has shown that, once transplanted,

the pig choroid plexus releases the right mix of growth

factors and can reverse Parkinson’s-like symptoms in animals.

Transplanting these pig choroid plexus cells has produced no

adverse events, so the next step is to test them in humans.

This sort of research is ground breaking. We know that in

medical research we need to take major steps such as occurred

when people were first given Deep Brain Stimulation for

Parkinson’s or when heart patients were first given pig valve

replacements. It is hoped that this treatment will be a major step

in the treatment of Parkinson’s.

How does this new treatment work?

Nerves attract other nerves to grow towards them by releasing

growth factors. In Parkinson’s the dopamine pathway nerves

die back in the brain. The cause of this dieback is not known.

The result is that the nerves become disconnected, and the

person develops the symptoms of Parkinson’s. This new

treatment aims to slow or stop the dieback of these nerves

by transplanting pig cells that release growth factors.

The treatment involves surgically placing cells producing the

growth factors into the brain to encourage the nerves that

have died back to regrow. This type of treatment has been tried

in humans, but the experiments so far have used only one

particular growth factor. This trial will use the mix of multiple

growth factors that are released by the part of the brain known

as the choroid plexus.

One of the problems of

transplanting pig choroid

plexus into humans is

that the human immune

system will destroy

the foreign pig cells.

This can be solved by

putting the pig cells

into tiny capsules

that shield the pig cells

from attack by the human

immune system.

The capsules are a little like Goretex in that they have

perforations that let nutrients in and the growth factors out

yet the perforations are too small to allow attack by the immune

system. We know that the pig cells can last for years inside

these capsules so the effect of this treatment is expected to

be long term.

Is it safe to use pig cells?

We have used pig tissue for medical treatments for many years,

and they are particularly useful for heart valve replacements.

The main concern in transplanting cells from pigs is that the

pigs may carry viruses that could be dangerous to humans.

For the Parkinson’s study, the pigs will come from a herd that

has lived in isolation on the Auckland Islands for over 200

years. The Auckland Islands are south of New Zealand near the

Antarctic and the pigs have been tested and found to be free

of dangerous viruses. They now live in special isolation near

Invercargill and Auckland.

How do people get involved in the trial?

We will approach patients already accepted for Deep Brain

Stimulation surgery and offer the opportunity to have the

capsules placed into the brain. We will assess the parkinsonism

carefully. If there is no improvement after 6 months, then the

person can have the Deep Brain Stimulation surgery they were

originally offered.

When will the trial be undertaken?

Although the study has been approved by Medsafe and the

Minister of Health, the next step is to present it to the Ethics

Committee and the Auckland District Health Board Review

Committee. Once approved has been gained, we will start

the trials in 2013.

INTERVIEW WITH DR BARRY SNOW

Dr Snow talks to The Parkinsonian about his ground breaking Clinical Trial

In October the Minister of Health announced authorisation had been given for a Phase 1 clinical trial into the safety

and clinical effect of pig cell transplants for people with Parkinson’s. The principal investigator of this trial is Dr Barry

Snow. He recently spoke to The Parkinsonian about the trial.

Dr Snow is a Neurologist and Medical Director of the Adult

Healthcare Service Group, Auckland District Health Board.

The team performing the study with Dr Snow are Mr Arnold

Bok, Neurosurgeon, Drs David McAuley and Mark Simpson,

Neurologists, Lorraine Macdonald, Parkinson’s nurse,

Greg Finucane, Neuropsychiatrist and Jamie Macniven,

Neuropsychologist. They will work closely with the theatre

team for the operation. The encapsulated cells are produced

by the NZ company, Living Cell Technology.