MADISON – Grafting neurons grown from monkeys’ own cells into their brains relieved the debilitating movement and depression symptoms associated with Parkinson’s disease, researchers at the University of Wisconsin-Madison reported today.
In a study published in the journal Nature Medicine, the UW team describes its success with neurons made from induced pluripotent stem cells from the monkeys’ own bodies. This approach avoided complications with the primates’ immune systems and takes an important step toward a treatment for millions of human Parkinson’s patients.
“This result in primates is extremely powerful, particularly for translating our discoveries to the clinic,” says UW-Madison neuroscientist Su-Chun Zhang, whose Waisman Center lab grew the brain cells.
Parkinson’s disease damages neurons in the brain that produce dopamine, a brain chemical that transmits signals between nerve cells. The disrupted signals make it progressively harder to coordinate muscles for even simple movements and cause rigidity, slowness and tremors that are the disease’s hallmark symptoms. Patients – especially those in earlier stages of Parkinson’s – are typically treated with drugs like L-DOPA to increase dopamine production.
“Those drugs work well for many patients, but the effect doesn’t last,” says Marina Emborg, a Parkinson’s researcher at UW-Madison’s Wisconsin National Primate Research Center. “Eventually, as the disease progresses and their motor symptoms get worse, they are back to not having enough dopamine, and side effects of the drugs appear.”
Scientists have tried with some success to treat later-stage Parkinson’s in patients by implanting cells from fetal tissue, but research and outcomes were limited by the availability of useful cells and interference from patients’ immune systems. Zhang’s lab has spent years learning how to dial donor cells from a patient back into a stem cell state, in which they have the power to grow into nearly any kind of cell in the body, and then redirect that development to create neurons.
“The idea is very simple,” Zhang says. “When you have stem cells, you can generate the right type of target cells in a consistent manner. And when they come from the individual you want to graft them into, the body recognizes and welcomes them as their own.”