We've made significant progress as a field. We can test stem cells in both animal models and human clinical trials. We can employ stem cells obtained from either fetal or adult cells or use more differentiated origins specific to cells in the central nervous system. https://www.einnews.com/pr_news/574764747/r3-stem-cell-now-offering-treatment-with-150-billion-exosomes-for-only-3950-usd