How does an embryonic stem cell differ from an adult stem cell?
Embryonic stem cells are able to differentiate into many different types of cell.
Adult stem cells are able to differentiate into other fully developed cells.
Embryonic stem cells do not require nuclear transfer for cloning.
Embryonic stem cells are more likely to uptake the plasmids required for iPSCs.
Embryonic stem cells and adult stem cells differ in several ways:
1. Potency: Embryonic stem cells have the highest potency and are considered pluripotent, meaning they can differentiate into cells from all three primary germ layers (endoderm, mesoderm, and ectoderm), giving rise to almost any cell type in the body. In contrast, adult stem cells are multipotent or unipotent, meaning they can only differentiate into a limited range of cell types.
2. Developmental stage: Embryonic stem cells are derived from the inner cell mass of a developing embryo, typically during the blastocyst stage. Adult stem cells, on the other hand, are found in differentiated tissues, such as bone marrow, blood, skin, and muscle, and serve as a repair mechanism for those specific tissues.
3. Source and availability: Embryonic stem cells are obtained from early-stage embryos, which raises ethical concerns as it involves the destruction of the embryo. Adult stem cells, on the other hand, can be isolated from adult tissues or even some umbilical cord or placental tissues without ethical controversies.
4. Proliferation and longevity: Embryonic stem cells have a greater capacity for self-renewal and proliferation. They can divide indefinitely under controlled conditions while maintaining their pluripotency. Adult stem cells have a more limited capacity for self-renewal and proliferation, often having to remain in a quiescent or dormant state until they are activated by tissue damage or specific signals.
5. Differentiation potential: Embryonic stem cells have a broader differentiation potential than adult stem cells. They can generate cells from all three germ layers, including cells from organs and tissues that adult stem cells cannot generate. Adult stem cells are typically restricted to differentiating into cell types found in the tissues or organs from which they are derived.
6. Clinical applications: Due to their versatile differentiation potential, embryonic stem cells have been extensively studied for potential therapeutic applications, such as tissue regeneration and disease modeling. Adult stem cells have more limited therapeutic applications but are currently used in various therapies, such as hematopoietic stem cell transplantation.
It is important to note that recent advances have led to the generation of induced pluripotent stem cells (iPSCs), which are adult somatic cells that have been reprogrammed back to an embryonic-like state. These iPSCs bypass the need for embryonic stem cells and have similar characteristics and potential as embryonic stem cells.