Stem Cells : Therapeutic Perspectives

@ Pankaj PrasadDepartment of Molecular & Human Genetics

BHU, Varanasi

“ The phenomenon of life itself negates the

boundaries that customarily divide

our

disciplines and fields.”

Hans Jonas (1966)

Stem Cells??

Definition

“ A Stem cell is a clonal, self-renewing

entity that is multipotent and thus can

regenerate several differentiated cell types.”

Embryonic Stem Cells (ESCs)

Embryonic stem cells

James A. Thomson The Thomson Laboratory

Sources of embryonic stem cells• In – vitro Fertilization (IVF)• Nuclear transfer

• The largest potential source of blastocysts for the stem cell research is from IVF clinics.

• As all fertilized eggs are not implanted, it results in a large bank of “excess” blastocysts, stored in freezers around the globe.

Somatic Cell Nuclear Transfer (SCNT)

Adult stem cells

Sources of adult Stem Cells

Induced Pluripotent Stem (iPS) cells

Shinya Yamanaka, M.D., Ph.D.Professor, Institute for Frontier Medical Sciences

Next generation iPS cells

Kevin C. EgganHarvard University Department of Stem Cell and Regenerative BiologyStowers Medical Institute

Epigenetic reprogramming

Konard Hochedlinger had shown that it is possible to create mouse iPS cells using an adenovirus in place of the retroviruses previously used. Harvard University Department of

Stem Cell and Regenerative BiologyMassachusetts General Hospital

Transdifferentiation Refers to the

conversion of one differentiated cell type to another and considered a subset of metaplasia.

Faculty of Arts and Sciences, Harvard UniversityHoward Hughes Medical Institute

Cancer Stem Cells (CSCs)

Cancer stem cellsCurrent cancer therapies may fail because cancer stem cells have not

been eradicated.

leave patients prone to recurrence.

Pulling out a weed while leaving the roots.

Origin of cancer stem cells

Treatment

Stem cell niches

Scadden D.T. Nature 2006

Scadden D.T. Nature 2006

Quiescence stem cells

Quiescence

Slow cell cycling of stem cells

Unresponsive to many chemotherapeutics that typically target

rapidly proliferative cells

Zebra fish : Model system for stem cell research

Harvard Magazine

Role in basic research

NIH, U.S.

Stem cell research centers

Stem cell research in India

Stem cells Banks

Major BMT centers in India

Bone Marrow Transplantation (2008Bone Mar08

EthicsMoral values

Law

Peer review

“Human reproductive cloning

should not be practiced. It is dangerous and likely to fail.”

Scientific and medical aspects of human reproductive cloning. National Academic Press, 2005.

Conclusion• Stem cell research is being pursued in the

hope of achieving major medical breakthroughs.

• Currently only a few diseases are treatable with stem cell therapies because scientists can regenerate only a few types of tissues.

• Future fundings will provide more insights into the mechanisms regulating the stem cell pluripotency.

References

Thanking you