Definition of Stem Cells
Stem cells are undifferentiated cells with the unique ability to divide and develop into specialized cell types in the body. They serve as a repair system, replenishing adult tissues and can differentiate into various cell lineages, making them foundational to development and regeneration.
Types and Key Properties of Stem Cells
Stem cells are classified by their differentiation potential: totipotent cells can form an entire organism, pluripotent cells (like embryonic stem cells) can become any cell type except placental cells, multipotent cells (such as adult stem cells) are limited to specific lineages, and induced pluripotent stem cells are reprogrammed adult cells with pluripotent properties. These properties enable self-renewal and specialization.
Practical Example: Bone Marrow Transplants
A common application is hematopoietic stem cell transplantation, used to treat leukemia. In this procedure, healthy stem cells from bone marrow or peripheral blood are infused into a patient after chemotherapy destroys diseased cells, allowing the stem cells to repopulate the blood system and restore immune function.
Importance and Future Applications in Medicine
Stem cells hold immense potential in regenerative medicine, offering treatments for conditions like Parkinson's disease, spinal cord injuries, and diabetes by replacing damaged tissues. They could enable organ regeneration and personalized therapies, though challenges like immune rejection and ethical concerns with embryonic sources persist; ongoing research addresses these to expand clinical uses.