In what is considered a major medical breakthrough, researchers at the Hadassah Medical Center in Jerusalem have succeeded in showing that human embryonic stem cells can improve the functioning of a laboratory rat with Parkinson’s Disease.

Findings of the research were published in the recent edition of the prestigious magazine Stem Cells.

Parkinson’s, the second most common degenerative disease of the nervous system, afflicts more than one and a half million people in the United States, and several thousand in Israel.

The disorder is caused by the selective death of a discrete cluster of nerve cells, which secrete the neurotransmitter dopamine, and whose function is to control the part of the brain that integrates motion. The disease expresses itself in the disturbance of movement – especially trembling or freezing of muscles – which severely disrupts daily functioning.

The research team, created cultures of primitive nerve cells from human embryonic stem cells and transplanted them into an area in the brain of a rat, where there were no dopaminergic nerve cells. A gradual, significant improvement in the functioning of the rats was noted. After three months it was clear that some of the transplanted human cells turned into dopaminergic nerve cells. The researchers emphasize that the percentage of transplanted cells that matured into dopaminergic nerve cells was not high and that the rats did not make a complete recovery.

The research team was headed by Prof. Benjamin Reubinoff, Director of Hadassah’s Center for Human Embryonic Stem Cell Research at the Goldyne Savad Institute of Gene Therapy and the Department of Gynecology, and Prof. Tamir Ben-Hur, senior physician in Hadassah’s Department of Neurology, the Agnes Ginges Center for Human Neurogenetics.

According to Reubinoff: “We are in the midst of research, in which we are trying to bring about the maturation of primitive nerve cells into dopaminergic nerve cells before we transplant them, in order to increase the number of dopaminergic cells in the implant – and to achieve complete reversal of Parkinson’s disease in the rats.” Human embryonic stem cells, which can reproduce endlessly in culture and mature into any type of cell in the body, have sparked wide international interest because of their potential to serve as an endless source of cells for transplantation. They hold the promise of improving the functioning of people suffering from a wide range of disorders, such as Parkinson’s, Alzheimer’s, diabetes or heart failure.

This is the first time that the potential ability of transplanted human embryonic stem cells has been demonstrated in an animal model with Parkinson’s disease. The research is the latest stage in a long series of trials aimed at using human embryonic stem cells to find a cure for people who suffer from Parkinson’s disease. The research was funded in part by the National Institute of Neurological Disorders and Stroke (NINDS), a component of the National Institute of Health (NIH) in the United States.