Scientists Treat Parkinson’s Disease With Brain Cell Transplants

Fetal mesencephalic tissue provides dopaminergic cells

Scientists in Europe are researching an experimental treatment approach that grafts dopamine cells into the brains of patients with Parkinson’s disease, according to news from the Community Research and Development Information Service (CORDIS). The TRANSEURO research project is studying patients with early-onset disease to determine their tolerance to transplanted fetal ventral mesencephalic tissue.

“We hope to be able to show that we can safely and effectively transplant dopaminergic cells into the brains of patients with Parkinson’s disease that produce dopamine and make many aspects of the disease better,” said Professor Roger Barker, TRANSEURO project coordinator.

Scientists have found that one of the main problems in the disease is the progressive loss of the neurotransmitter dopamine in the brain. As dopamine levels drop, a patient may develop rigidity, bradykinesia, tremors, and problems with gait and posture.

Today, treatments for Parkinson’s disease counteract the loss of dopamine with symptomatic dopaminergic drug therapies, such as levodopa. However, as the disease progresses these medications are less effective and can trigger new problems, such as drug-induced motor complications.

TRANSEURO’s approach dates back to the 1980s. Clinical trials involving the transplant of human fetal dopaminergic neurons were first conducted in Sweden. These studies showed that the transplanted cells could survive and function for a significant period while helping patients to counter bradykinesia and rigidity.

“For many patients, this led to a reduction in their medication, and some were able to stop taking it altogether for some time. However, some patients developed graft-induced problems with involuntary movements driven by the transplant, which were so severe that some patients had to undergo neurosurgical interventions to reduce them,” Barker remarked.

The TRANSEURO program is aiming to move transplant technology into new territory. The project has improved the way cells are prepared for grafting, including how they are stored before implantation. Moreover, the investigators are focusing on younger patients, who are more likely to benefit from the treatment.

“The project has gathered all available expertise to eliminate the risk of the previous complications. Grafting technologies have been improved, as well as patient selection. We hope this new trial will pave the way for the introduction and testing of stem cell-based dopamine treatments for Parkinson’s,” Barker said. Using stem cells would avoid using fetal tissue, which can be in short supply, delaying procedures.

The first TRANSEURO patient was grafted using dopamine cells from fetal tissue in May 2015. Barker hopes that the project, along with two other projects––EUROSTEMCELL and NEUROSTEMCELL REPAIR––will lead to the first human transplant trial using stem cell-derived dopamine neurons in 2018 or 2019.

Source: CORDIS; July 15, 2016.