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 limited proliferation capacity.

- Stimulating their growth by growth factors

diminishes their secretory 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- Embryonic germ 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 to grow and proliferate

* but limited capacity to produce insulin.

: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 Structure

Three 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 and glucagon 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- Differentiation

How: : By using different media to suppress other cells and Fibroblasts to provide Growth Factors,Transcription Factors with supplements of Nicotinamide , etc

.

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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 express insulin ) . 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 marrow transplant: 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.

Thank You