Adult stem cell transplant improves motor functions in monkeys suffering from Parkinson’s Disease

By Dave Andrusko

The improvement was called “a small but hopeful step,” but had the improvement in monkeys with Parkinson’s been the result of the infusion of embryonic stem cells rather than adult stem cells, it would been trumpeted all over the front pages of the Washington Post and the New York Times.

But, be that as it may….

In the issue of the Journal of Clinical Investigation published Monday, researchers led by Takuya Hayashi at the RIKEN Center for Molecular Imaging Science in Kobe, Japan, used stem cells harvested from the monkeys’ own bone marrow and found that while not cured, the macaques did demonstrate improved motor skill function.

Parkinson’s “is caused by loss of the neurons that produce the neurotransmitter dopamine (known as dopaminergic neurons),” the Los Angeles Times’ Eryn Brown reported. The suggestion is that the stem cells from bone marrow treatment might someday be used in treating humans suffering from Parkinson’s disease, which is characterized by tremors and loss of balance, among other seriously debilitating symptoms

To test their theories the team removed bone marrow from the hip bones of five monkeys, isolating mesenchymal stem cells, Brown reported. The next step was to use a previously reported method to turn these cells into dopamine-producing neurons.

Although it is always underplayed, a recurring problem with human embryonic stem cells is that they tend to form tumors. But in addition to improved motor skill performance, Brown writes that

“The monkeys did not develop tumors, always a concern with stem-cell based therapies. Because the cells came from the monkeys’ own bone marrow, tissue rejection wasn’t an issue either.”

In addition,

“Through the use of PET scans and postmortem tissue analysis, the researchers determined that the implanted neurons continued producing small amounts of dopamine for at least nine months.”

Moreover, since the stem cells came from the animals’ own adult stem cells, the research “sidestepped availability issues and ethical considerations involved in using fetal tissue,” the scientists wrote.

Further studies will be needed to improve the viability of the cells once implanted before the treatment might be considered appropriate for humans, the Japanese team reported.  But, they added, the approach “may expand the availability of cell sources for cell-based therapies for patients with Parkinson’s disease.”