Neural stem cells (NSCs) have revolutionized regenerative medicine, offering new hope for treating central nervous system (CNS) injuries. Over the past two decades, advancements in this area have progressed rapidly, opening the door to potential therapeutic applications.
“Neural stem cells have the potential to replace damaged cells and restore lost function.”
National Institute of Neurological Disorders and Stroke (NINDS)
What Are Neural Stem Cells?
Neural stem cells (NSCs) are cells within the nervous system. They can self-renew and differentiate into various progenitor cells. Eventually, they generate neurons and glial cells, including astrocytes and oligodendrocytes. Today, numerous animal studies demonstrate the safety of stem cell therapies for regenerating neurological damage.
The Challenge of CNS Injuries
Despite significant medical advancements, CNS diseases or injuries remain impactful. The brain’s limited ability to recover results in permanent neurological deficits. This challenge has driven the search for new therapeutic strategies to regenerate damaged tissue, including neural stem cell (NSC) therapy.
Proliferative Centers in the Adult Brain
Two primary proliferative centers in adult mammals have been identified. These centers are where stem cells reside. They are the lateral ventricles’ subventricular zone (SVZ) and the hippocampal dentate gyrus. Additional regions contain cells with proliferative potential. These regions include the third ventricle, the ependymal canal of the spinal cord, and the cerebral cortex. However, their neurogenic activity and functional implications remain less understood.
Early Discoveries of Neural Stem Cells
The first NSCs were discovered in the SVZ. In the late 20th century, the research teams of Arturo Álvarez-Buylla at the University of California, San Francisco, and the University of Valencia identified that type B cells or radial astrocytes were the adult CNS stem cells in rodents.
Experimental Evidence
One significant experiment involved using an osmotic pump to deliver an anti-mitotic drug (cytosine arabinoside) into the cerebral ventricle of animals, resulting in the death of actively dividing cells. Analysis of the SVZ immediately after the infusion revealed the presence of radial astrocytes (slow-dividing cells) and ependymal cells (non-dividing ventricular lining cells). Young neurons repopulate the subventricular zone within days of removing the anti-mitotic substance.
The Regenerative Potential of Neural Stem Cells
Neural stem cells, linked to aging, neurodegenerative diseases, and cancer, may hold the key to regenerating brain areas damaged by diseases or trauma. Scientists previously believed the brain could not produce new neurons, assuming humans were born with a fixed number of nerve cells that declined over time.
Recent Discoveries
However, Dr. José García Verdugo’s team, a specialist in stem cells and Professor of Cellular Biology at the University of Valencia, Spain, recently discovered the presence and location of neural stem cells in the brain. These cells can self-renew and continually produce neurons, astrocytes, and oligodendrocytes, suggesting they could help repair damaged brain regions. However, as Dr. García Verdugo notes, they cannot produce all types of neurons, making them currently unsuitable for treating Alzheimer’s disease.
Factors Affecting Neural Stem Cells
Neural stem cells can be damaged or deteriorated due to various factors, including alcohol or drug use, certain medications, and lack of cognitive activity. Without replacement, the death of these cells leads to brain aging, impairing learning and memory and potentially causing neurodegenerative diseases.
Recommendations for Brain Health
Finally, experts recommend maintaining constant cognitive activity, engaging in new activities, fostering social relationships, and regularly challenging oneself to prevent these adverse effects.
