**2.3. Use of placental mesenchymal stem/stromal cells in neurological diseases**

Neurodegeneration involves a progressive and irreversible loss of neurons. Alzheimer's, Parkinson's, and multiple sclerosis are some of the more studied neurodegenerative syndromes. The neuromuscular disorder amyotrophic lateral sclerosis (ALS) is a degenerative process caused by motor neuron loss. To date, there is no cure for these diseases. Cell therapy with stem cells arises as a therapeutic alternative based, either on the replacement of the lost neurons, or on a neuroprotective action through release of neurotrophic factors. PMSC are able to differentiate in vitro into several neural lineages, including neurons [9, 66], oligodendrocytes [66], glial cells [67], and dopaminergic neurons [68].
