The Historical Evolution From Embryonic Stem Cell Research to Commercial Cell Therapy By Prof. Morsi...

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