Every human being is born from a single totipotent cell called an embryo. As we undergo different stages of development, our bodies develop several body organs using totipotent cells. Once we become adults, our body keeps a few extra cells of these cells that have the potential to differentiate into other cell types. We call these cells stem cells. Even in adult bodies, you will find stem cells in bone marrow and adipose tissue. Scientists have employed these stem cells to differentiate into different types of tissues, including nerve cells and muscle cells.
During stem cell therapy for autism , individuals are given stem cells intravenously (in the bloodstream). Once in the bloodstream, the stem cells travel to the areas of the damaged tissue. And yes, stem cells can cross the blood-brain barrier, which several drugs are not able to pass through.
These abilities of stem cells place them at the forefront of autism treatment.