Embryonic stem cell

Embryonic stem cells (ES cells) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells.

Characteristics

Embryonic stem cells display two distinctive properties: pluripotency and the ability to self-renew. Pluripotency refers to a stem cell's ability to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system).

Uses and Research

Embryonic stem cells are used in various research contexts. Their main use is in regenerative medicine and tissue replacement after injury or disease. These cells can also be used in drug discovery and biotoxicity screening, which can play a significant role in pharmaceutical development.

Controversy and Ethics

The use of human embryonic stem cells evokes ethical concerns, because the blastocyst-stage embryos are destroyed in the process of obtaining the stem cells. The ethical status of embryos is a subject of intense debate and varies among different ethical and cultural views.

See Also

• Stem cell controversy
• Induced pluripotent stem cell
• Adult stem cell
• Stem cell treatments