42.5: Stem Cell Therapy for Tissue Regeneration
Stem cell therapy is a method used in regenerative medicine to repair and restore function to damaged tissues and organs. Stem cells have the potential to proliferate and differentiate into various tissue types, making them ideal candidates for tissue regeneration. For example, hematopoietic stem cell transplants are commonly used in blood cancer treatment to replenish damaged bone marrow and restore healthy blood cells.
Types of Stem Cells used in Stem Cell Therapy
The two main cell types that have the potential for use in stem cell therapy are adult stem cells and embryonic stem cells (ESCs). However, ESCs, derived from the blastocyst, require the sacrifice of embryos, which raises several moral and ethical issues. Hence, adult stem cells, such as hematopoietic (HSCs) and mesenchymal stem cells (MSCs), are more commonly used for regenerative therapy despite their limited differentiation potential.
HSCs and MSCs are both primarily found in the bone marrow of adults and the umbilical cord blood. While HSCs can differentiate and produce different blood cells, including RBCs and WBCs, MSCs can differentiate into tissues of the heart, liver, muscle, bone, and also some nerves.
Strategies in Stem Cell Therapy
Stem cell therapy is a complex process that requires optimization at each stage. Optimization depends on many factors, such as the source of stem cells, the target tissue, and the recipient's health condition. For example, intravenously administered HSCs can establish and proliferate in the bone marrow. In contrast, direct administration of stem cells at the target site is more efficient for the local repair of tissues in organs such as the heart, kidney, liver, and muscle. In such tissues, the timing of stem cell introduction also plays a crucial role in determining repair efficiency. When stem cells are administered too early, such as just after the injury occurs, the inflammatory process impairs the proliferation of these stem cells. However, if stem cells are introduced during the repair phase, they are more readily incorporated into the tissue and can proliferate to repair the damage.
