Dr. Abdullah Aldahmash

Cell Stem Cell – Definition A cell which has the ability to continuously divide and differentiate into various other kinds of cells/tissues

DescriptionPotency 1-3 days, differentiate into embryonic and extraembryonic cell types Totipotent Descendants of totipotent cells and differentiate into cells of 3 germ layers Pluripotent Produce cells of a closely related family of cell (e.g. hematopoietic stem cells Multipotent Differentiate into ONLY a few cells, such as lymphoid or myeloid stem cells Oligopotent Produce ONLY one cell type (e.g. muscle stem cells) Unipotent The terminal cellNullpotent Classifications of stem cells I

Found in specific mature body tissues as well as the umbilical cord and placenta after birth. They also can be isolated of developing embryos’ different tissues Adult stem cells ( Tissue Specific Stem Cell)

Embryonic Stem Cell Embryonic human stem cells were first isolated in 1995 by Dr. James Thomson. Source of ESC is Blastocysts (IVF, SCNT)

SCNT The aim of this procedure is to obtain stem cells that are genetically matched to the donor organism. Not all of the donor cell's genetic information is transferred, as the donor cell's mitochondria that contain their own mitochondrial DNA are left behind The basis of this technique is cloning animals (such as the famous Dolly, the sheep). The importance of SCNT-based stem cell research has been decreased by the development and improvement of alternative methods of generating stem cells. The importance of SCNT-based stem cell research has been decreased by the development and improvement of alternative methods of generating stem cells.

SCNT

iPS It occurs by the introduction of a defined and limited set of transcription factors and culturing these cells under ES cells conditions. A retroviral-mediate introduced to four transcription factor (OCT3/4, SOX2, c-MYC, KLF4) could induce pluripotency. This protocols has been applied to mouse cells and human somatic cells. Nishikawa, S et.al., 2008

iPS iPS Skin cells were taken from the tail tip of a sickle-cell model mouse. The cells were differentiated into hematopoietic cells. The produced cells were transfused back into the sick mouse Hanna J. et.al., 2007

+LIF Self-renewal differenti ation

Thomson et al., 1998.

Secrete unknown factors to the media

Characterization of Human ESCs Sox17 Sox9 Beta-III tubulin SSEA-4Sox-2 Oct-4

Isolate inner cell mass (destroys embryo) Heart muscleNeurons Beta-cells “Special sauce” (largely unknown) Day 5-6 Blastocyst Inner cells (forms fetus) Outer cells (forms placenta) Heart repaired Culture cells

The Promise of Stem Cell Technology Replacement of tissues/organs Repair of defective cell types. Study cell differentiation Toxicity testing. Understanding prevention and treatment of birth defects. Study of development and gene control. Study of drugs therapeutic potential.

current advances in Stem Cells therapy Cell based therapy Tissue engineering

Obstacles of Stem Cell Research How to find the right type of stem cells? How to put the stem cells into the right place? Will the stem cells perform the desired function in the body? Differentiation protocols for many cell types have not been developed.