Stem Cells

Stem cells are undifferentiated, self-renewing cells that can develop into specialised cells. They act as the body’s growth and repair system.

• Embryonic stem cells:
• Found in early embryos
• Pluripotent → can form any cell type
• Very useful in medical research

• Found in tissues like bone marrow
• They are multipotent which form a limited range of cells.
• Used in bone marrow transplants

Collected from umbilical cord blood

• They divide to produce more stem cells (self-renewal).
• They receive chemical signals that trigger differentiation into specialised cells (e. g., nerve, muscle, blood).

• Totipotent means they can form all cell types. Example: zygote/egg
• Pluripotent means they can form any body cell
• Multipotent has a limited range
• Unipotent means they have one cell type but still self-renewing

• Treating blood cancers (leukaemia) using bone marrow transplants
• Repairing damaged tissues (heart muscle, nerve cells)
• Therapeutic cloning to produce genetically matched cells
• Research into diabetes, spinal injuries, Parkinson’s disease

• Embryonic stem cell use involves destroying embryos → moral concerns
• Adult stem cells avoid ethical issues but have limited potential

• Tumour formation if cell division becomes uncontrolled
• Immune rejection if cells are not patient-matched
• Ethical concerns for embryonic sources

• Regenerative Medicine
• Replacing damaged tissues (heart, spinal cord, retina)
• Creating lab-grown organs (research stage)

• Stem cells used to grow “mini-organs” (organoids)
• Helps study diseases like Alzheimer’s, cancer, cystic fibrosis

Stem-cell-derived tissues allow safer drug trials before human testing

• Combine stem cells with gene editing (CRISPR)
• Correct genetic defects → re-implant corrected cells