The proximate cause of the most visible symptoms of Parkinson's disease is the progressive loss of a small but vital population of dopamine-generating neurons. This loss happens to everyone, but for a variety of underlying reasons, not all of which are clear at this time, people with Parkinson's experience a more rapid loss of these cells. This is the case for many age-related medical conditions: they are a more rapid progression of a process that is in fact happening to all of us, and so the development of therapies is worth keeping an eye on. One approach to the treatment of Parkinson's disease is to attempt to restore the failing population of dopamine-generating neurons via some form of cell therapy, as demonstrated here in rats:
Parkinson's disease (PD) is considered the second most frequent and one of the most severe neurodegenerative diseases, with dysfunctions of the motor system and with nonmotor symptoms such as depression and dementia. Compensation for the progressive loss of dopaminergic (DA) neurons during PD using current pharmacological treatment strategies is limited and remains challenging. Pluripotent stem cell-based regenerative medicine may offer a promising therapeutic alternative, although the medical application of human embryonic tissue and pluripotent stem cells is still a matter of ethical and practical debate.
Addressing these challenges, the present study investigated the potential of adult human neural crest-derived stem cells derived from the inferior turbinate (ITSCs) transplanted into a parkinsonian rat model. Emphasizing their capability to give rise to nervous tissue, ITSCs isolated from the adult human nose efficiently differentiated into functional mature neurons in vitro. Transplantation of predifferentiated or undifferentiated ITSCs led to robust restoration of behavior, accompanied by significant recovery of DA neurons within the substantia nigra. ITSCs were further shown to migrate extensively in loose streams primarily toward the posterior direction as far as to the midbrain region, at which point they were able to differentiate into DA neurons within the locus ceruleus. We demonstrate, for the first time, that adult human ITSCs are capable of functionally recovering a PD rat model.