Health Biotechnology Stem Cell LECTURE 20: Health Biotechnology Stem Cell Biotechnology; 3 Credit hours Atta-ur-Rahman School of Applied Biosciences (ASAB) National University of Sciences and Technology (NUST)

What are Stem cells Unspecialised cells lacking any tissue-specific structure Can give rise to specialised cells through the process of differentiation Stem cells are the raw material from which all of the body’s mature, differentiated cells are made. Stem cells give rise to brain cells, nerve cells, heart cells, pancreatic cells, etc.

Stem Cells !!! stem cell (copying) (specializing) specialized cell SELF-RENEWAL (copying) DIFFERENTIATION (specializing) specialized cell e.g. muscle cell, nerve cell stem cell

Stem Cell Definition A cell that has the ability to continuously divide and differentiate (develop) into various other kind(s) of cells/tissues Stem Cell

Kinds of Stem Cells Cell type Description Examples Totipotent Each cell can develop into a new individual Cells from early (1-3 days) embryos Pluripotent* Cells can form any (over 200) cell types Some cells of blastocyst (5 to 14 days) Multipotent* Cells differentiated, but can form a number of other tissues Fetal tissue, cord blood, and adult stem cells *The pluripotent stem cells are in fact derived from totipotent stem cells. The pluripotent stem cells can develop into any cell type except for the extra-embryonic tissue. *Multipotent progenitor cells can give rise to many but limited types of cell. For example, a hematopoietic cell can give rise to several types of blood cells (i.e. red blood cells, white blood cells, platelets, etc.)

Tissue Differentiation Totipotent Stem Cells Day 2 2-cell embryo Day 3-4 Multi-cell embryo Day 1 Fertilized egg Day 5-6 Blastocyst Day 11-14 Tissue Differentiation

Multipotent Stem Cells

Stem Cell types: Origin Stem Cells comprise the following Types Embryonic Stem Cells Fetal Stem Cells Umbilical Stem Cells Adult Stem Cell

A human embryo is considered fetus 8 weeks after the egg is fertilized

1- Embryonic Stem Cells Usually they are pluripotent cells Most valuable can become into any type 1998 first human embryonic cell was grown In invitro fertilization (IVF) Extra embryo that are not implanted are frozen

Embryonic Stem Cells

2- Fetal Stem Cells These are also pluripotent Fetus brain tissue They are excellent source of cells for adults with Parkinson’s disease

3- Umbilical Stem Cells The cells from cord blood are multipotent stem cell. They can naturally develop into blood cells and immune cells Cord blood cells are highly suitable because they have less rejection. They also lack mature immune cells that can attack the recipient body. Cord cells can be store and it can be denoted by woman after giving birth. Cord blood bank

4- Adult Stem Cell Numerous multipotent adult stem exist in body Can develop into cells of specific types of the tissue These are least plastic in term of differentiation Much research is focused in this area

Application of Stem Cells

Induced pluripotent stem cells (iPS cells) adult cell ‘genetic reprogramming’ = add certain genes to the cell induced pluripotent stem (iPS) cells behave like embryonic stem cells all possible types of specialized cells culture iPS cells in the lab differentiation Advantage: no need for embryos!