A article on science daily was published regarding how monkeys with Parkinson's disease are benefiting from human stem cells.
Parkinson's disease degenerates cells in the brain known as dopaminergic (DA) neurons. When the symptoms of Parkinson's are found, it most likely appears that more than half of the DA neurons are lost in the brain of the individual. Neurosurgeons are planning on using DA neurons created from iPS cells to treat these patients with the disease. iPS cells are made from blood and skin cells which makes them easily obtainable. This idea is being tested for its safety and reliability, so they are trying the experiment on monkeys that have Parkinson's by transplanting the new cells in the monkeys brains.