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The Historical Evolution From Embryonic Stem Cell Research to Commercial Cell Therapy By Prof. Morsi Arab University of Alexandria. IN GENE THERAPY We aim to generate a source of cells which can secrete insulin in response to glucose.
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The Historical Evolution From Embryonic Stem Cell Research to Commercial Cell Therapy By Prof. Morsi Arab University of Alexandria
IN GENE THERAPY We aim to generate a source of cells which can secrete insulin in response to glucose. .
B- cells express two specialized proteins important for the glucose sensoring:-I - Glucose Transporter(GLUT2).II - Glucose phosphorylating Enzyme (Glucokinase ) .
Sources for Production of Genetic B- Cells I- Mature B- cells : - Allogenic - Xenogenic II- B-cell Precursors, including Stem Cells. III- Genetically engineered Non B-Cells (e.g. Hepatic )
The mature B-cells as a source are : Limited in number. - Have very limitedproliferation capacity. - Stimulating their growth by growth factors diminishes theirsecretory power.
Stem Cells are clonogenic cells capable of Self renewal and multilineage differentiation. • So , they can be expanded in vitro and in vivo. • Stem Cells are : * Totipotent * Pluripotent * Multipotent
Sources of Stem Cells (SC): 1- Embryonic Stem Cells *(ethical problems) 2- Embryonicgerm cells. *(ethical problems) 3- Embryonic Carcinoma cells (?) 4- Adult stem cells avoids the ethical dilemma can allow auto transplantation
Advantage of developing B-cells from Stem Cells ? The Stem Cell has * high capacity togrowandproliferate * but limited capacity toproduceinsulin.
: Stages of Beta cell development and differentiation - Fetal Entoderm. cell ( high growth potentiality) - Panc. Duct epith. Cell - Committed Endoc. precursor cell - Growth Stimulated B-cell - Mature B- cell (V. low division capacity)
During Differentiation of Embryonic Stem Cells (ESC) to insulin Secreting StructureThree Observations :1- The endoc. Panc. Cells exist in clusters of 4 types of cells organized in stereotypical topology. 2- They develop in close contact with neurons… [ similar mechanisms control development of Endocrine and CNS systems …!!!]. 3- An early step in neural differentiation of ESC is generation of cells expressing NESTIN.
NESTIN- Nestin is an intermediate filament protein normally found in neural precursor cells . - It is also identified in immature pancreatic cells which upon differentiation in vitro give rise to insulin andglucagon producing cells .
Steps for experimental bioengineering of Insulin expressing cells from Embryonic stem cells include:1- Production of enriched population of Nestin +ve cells 2- Selection 3- Expansion , and 4- DifferentiationHow: : By using different media to suppress othercells and Fibroblasts to provide GrowthFactors,Transcription Factors with supplements of Nicotinamide , etc
. ============================ In order to achieve : I- growth . II- differentiation. III- secretion of insulin in response to glucose.
Testing the potentials of the islet-like clusters to survive and function in vitro : (when grafted(subcut) in diabetic mice ) 1- implanted cells vascularize ,and 2- remain immuno-reactive to insulin (i.e. continue to expressinsulin ) . 3- form aggregates similar morphologically to normal pancreatic islets .
A New Source of Stem Cells From Umbilical Cord Blood Available for collection at child birth and storage for future use for the same child . Currently, only few clinical diseases : heart disease , spinal cord lesions, leukemia , diabetes…? but with potential increases in the future. (Statistically: 5-37/1000 ), is it worth to be a routine ….?
Umbilical Cord Stem Cells : Collection and Storage (cont. ) * Special advantages over bone marrowtransplant: immediately available - genetically identical - no risk of rejection or infection . * Specially recommended with family history of genetic diseases which are treatable by stem cells. • In USA:private stem cell storage banks. In UK: storage is still debatable. But Donations of stem cells from Cord blood is established.