ANIMATED HEALTHCARE LTD/SPL

Defective brain neurons are responsible for the mobility problems seen in people with Parkinsons disease.

A neurosurgery team will next month transplant cells from aborted human fetuses into the brain of a person with Parkinsons disease. The operation breaks a decade-long international moratorium on the controversial therapy that was imposed after many patients failed to benefit and no one could work out why.

But the trial comes just as other sources of replacement cells derived from human stem cells are rapidly approaching the clinic. And this time, scientists want to make sure that things go better. So the teams involved in all the planned trials have formed a working group to standardize their research and clinical protocols in the hope that their results will be more easily interpretable.

People with Parkinsons disease suffer from a degeneration of neurons that produce the neurotransmitter dopamine, which is crucial for normal movement. This often leaves patients with severe mobility problems. Standard treatment includes the drug l-dopa, which replaces dopamine in the brain but can cause side effects. The cellular therapies aim to replace the missing neurons with dopamine-producing (dopaminergic) cells from fetal brains or with those derived from human stem cells.

The moratorium on replacement-therapy trials was introduced in 2003 because the early fetal-cell studies had produced varying results that were impossible to interpret.

We want to avoid a repeat of this situation, says neurologist Roger Barker at the University of Cambridge, UK, who helped to organize the working groups inaugural meeting in London last month. The group, known as the Parkinsons Disease Global Force, includes scientists from the European, US and Japanese teams about to embark on the trials. At the meeting, they pledged to share their knowledge and experiences.

The first human transplantation of fetal brain cells took place in 1987 at Lund University in Sweden, where the technique was pioneered. Surgical teams took immature fetal cells destined to become dopaminergic neurons from the midbrain of aborted fetuses and transplanted them into the striatum of patients brains, the area of greatest dopamine loss in Parkinsons disease.

More than 100 patients worldwide received the therapy as part of clinical trials before the moratorium. But centres used different procedures and protocols it was impossible to work out why some patients did very well and others didnt benefit at all, says Barker.

In 2006, Barker, together with neuroscientist Anders Bjrklund at Lund University, set up a network to bring together the original seven teams that had performed the transplants, to assess all protocol details and patient data retrospectively.

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Fetal-cell revival for Parkinsons