STEM CELLS: A Review

Potency TOTIPOTENT – cells that can become any type of cell - Ex. Embryonic SC (ESC) PLURIPOTENT – cells that can become almost any type of other cell ; comes from the late stages of an embryo (can become any of the three germ layers – ectoderm , mesoderm, endoderm ; but not extraembryonic tissue i.e. placenta) MULTIPOTENT – cells that can only become a limited number of other types of cells - Ex. Adult (somatic) stem cells

Two Types Embryonic SC Come from embryos Totipotent /Pluripotent -- Can become any cell type **The most potential for therapeutic use Adult (Somatic) SC Come from adults, children, infants Multipotent Found in developed tissues where they regulate growth and replace worn out / sick cells

Stem Cell: Self-Renewal Asymmetric Division (Self-Renewal) – when stem cells divide, they give rise to a cell that differentiates and a cell that stays a stem cell Differentiate  to specialize (stem cell  red blood cell) It takes on an identity

Stem Cells: What’s the Fuss? Because they are undifferentiated cells, they have the potential to become any type of cell Regenerative Medicine (spinal cord injury, etc) Blindness Deafness Cancer *The potential uses are endless*

The Controversy… “The stem cell controversy is the ethical debate centered on research involving the creation, usage, and destruction of human embryos. Most commonly, this controversy focuses on embryonic stem cells. Not all stem cell research involves the creation, usage and destruction of human embryos. For example, adult stem cells or induced pluripotent stem cells, which do not involve creating, using or destroying human embryos, is minimally controversial.”

iPS Induced Pluripotent Stem Cells Adult stem cells that are re-engineered to act like embryonic stem cells (by either inserting four genes or the gene products (proteins) into the cells) But…there are some issues with these Cancer risk (if you insert the actual genes) Not economically feasible A good step toward personalized medicine