Fetal Cell Transplants Can Work for Parkinson's
Nov. 22, 1999 (Atlanta) -- It's still an investigational procedure -- as well as a controversial one -- but for the first time, researchers have evidence that brain cells transplanted from fetal tissue into the brain of a Parkinson's disease patient work as intended. That is, the cells store and release dopamine -- a chemical that allows the smooth movement of muscles. It is the lack of dopamine that is thought to contribute to the rigidity and tremors seen in the disease.
"The importance of this study is that we've been able to demonstrate that the implant works," says lead author Paolo Piccini, MD, a neurologist at Imperial College School of Medicine, Hammersmith Hospital, London. "The next step is to find an alternative to fetal cells."
Five healthy subjects and one Parkinson's patient -- a 59-year-old man who underwent a fetal cell transplant to a part of the right side of his brain some 10 years ago, after his symptoms had become debilitating -- participated in the study. Physically, his recovery was dramatic. Within three years, he was able to stop taking his medication, called L-dopa, and after about five years he discontinued therapy to prevent rejection of the transplanted cells.
The patient was put back on a low dose of L-dopa about six years after the surgery -- but Piccini says it's because the disease began to affect the left side of his brain, which didn't get a fetal cell transplant. That's the dose he remains on today -- with just an intermittent tremor and only slight problems with muscular movements.
Piccini says follow-up tests showed that the operation works, but only in some patients and not in others. "If the operation does not improve the patient," she says, "the operation has not been performed properly. Many things can go wrong. The cells need to be the right age and prepared very carefully."
Of course, the real question is whether the operation can ever become widely available -- given that the current source of the transplant cells is aborted fetuses. Piccini says she's confident alternate sources will be found. Research is currently looking into the possible use of animal cells, especially from pigs -- as well as human cells from other sources. "When we have a different source of cells," she says, "it will become available to a large number of patients."