stemcell

Stem cells are undifferentiated cells with the ability to self-renew and to differentiate into specialized cell types. They provide a source for growth, repair, and development in organisms, and their properties are studied to understand how tissues form and function.

Embryonic stem cells are pluripotent cells derived from the inner cell mass of the early embryo and can give rise to cell types from all three germ layers. They are typically studied in culture under controlled conditions and raise ethical and regulatory considerations related to the use of human embryos.

Adult, or somatic, stem cells reside in tissues such as bone marrow, skin, and the brain, and are usually multipotent or unipotent, generating related cell types for tissue maintenance and repair. They contribute to normal tissue homeostasis and regenerative processes in the body.

Induced pluripotent stem cells (iPSCs) are formed by reprogramming mature cells to a pluripotent state, offering patient-specific cells without embryonic sources. iPSCs enable disease modeling and potential autologous therapies while avoiding some ethical issues.

Stem cells can be guided to differentiate into specific lineages, enabling the creation of organoids and tissue models for research, drug testing, and potential therapies. These capabilities support advances in developmental biology, toxicology, and regenerative medicine.

Applications include regenerative medicine and hematopoietic stem cell transplantation; many other uses are in clinical trials or regulated as approved therapies in some jurisdictions. Safety and ethical considerations, including tumorigenicity, immune compatibility, and informed consent, shape ongoing oversight and policy.