Stem Cell Therapy for Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder of aging after Alzheimer's disease (AD). Pathologically, it is characterized by a degeneration of dopamine (DA) neurons in substantia nigra of middle brain, which causes the motor symptoms and nonmotor symptoms of PD. The dopamine replacement therapy using levodopa and surgical treatment of deep brain stimulation (DBS) can only improve the symptoms of PD, but cannot stop the disease progression. Because of the selective loss of DA neurons, cell transplantation provides an exciting potential for the treatment of Parkinson's disease. The available cell sources include mesenchymal stem cells (MSCs) from bone marrow, neural stem cells (NSCs) from fetal brain tissues, embryonic stem cells (ESCs) from blastocysts, and induced pluripotent stem cells (iPSCs) reprogrammed from somatic cells transfected with stem cell transcription factors of OCT4, SOX2, KLF4, and c‐MYC. Here, we first review the research advance conducted in animal models and patients of PD with these cells, then moving forward to recent development of iPSCs as a future source for the treatment of PD, and highlight the current challenges to make good manufacturing practice (GMP) standard cells suitable for large‐scale production to move the cell‐based therapy from dish to clinic as soon as possible.