How do endogenous and exogenous stem cell therapies differ in stroke research?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram showing the locations of neural stem cells in brain regions such as the hippocampus and ventricles, and hematopoietic stem cells in the bone marrow and blood, with labeled illustrations of the brain, spinal cord, circulatory system, and skeleton. — stem cell Stem cells of neural and hematopoietic origin have tremendous potential in the development of therapies for certain diseases, such as diabetes and Parkinson disease. Neural stem cells occur in the spinal cord and in specific regions of the brain, and hematopoietic stem cells occur in the blood and bone marrow.

In stroke research, stem cell therapies are categorized into two primary approaches: endogenous and exogenous. These methods differ fundamentally in their source and application.1

Endogenous Stem Cell Therapy

The endogenous approach focuses on stimulating the patient’s own neural stem cells (NSCs) already present in the body. Researchers administer growth factors—such as erythropoietin, fibroblast growth factor-2, or brain-derived neurotrophic factor—to induce or enhance neurogenesis. The goal is to activate these dormant cells to repair damaged tissue and promote functional recovery following a stroke.1

Exogenous Stem Cell Therapy

Exogenous therapy involves the extraction, in vitro cultivation, and subsequent transplantation of stem cells into the stroke-affected regions of the brain. These cells may be derived from various sources, including adult NSCs, embryonic stem cells, or hematopoietic stem cells. While grafted cells have shown the ability to differentiate into neurons and glial cells, significant challenges remain. Scientists must still determine how to effectively control the survival, migration, and integration of these transplanted cells into existing neuronal networks, as their behavior is heavily influenced by the specialized microenvironment, or niche, where they reside.1