Stem Cells and Regeneration

의공학개론 , Fall 2012

Anne J. Kim, Ph.D.

Stem Cells: A Timeline 1981 – Embryonic stem cells (ESCs) are isolated in

mice 1995 – ESCs are isolated in rhesus monkeys 1998 – Researchers isolate the first human

embryonic stem cells (hESCs) 2001, 2004 – Scientists claim to have cloned a

human embryo 2006 – Researchers say it is possible to derive

hESCs without harming human embryos 2007 – Stem cells derived from amniotic fluid are

able to produce bone, liver, and brain tissue 2007 – Researchers modify a skin cell so that it acts

like an embryonic stem cell

Regeneration: The action or process of regenerating or being regenerated, in particular the formation of new animal or plant tissue.

In other words, the search for the fountain of youth and the hope for immortality…

Prometheus Bound, Peter Paul Rubens; The Raising of Lazarus, Vincent Van Gogh

Limb regeneration in salamanders:The arms that keep growing back…

Lévesque M, Gatien S, Finnson K, Desmeules S, Villiard É, et al. (2007) Transforming Growth Factor: β Signaling Is Essential for Limb Regeneration in Axolotls. PLoS ONE 2(11): e1227.

doi:10.1371/journal.pone.0001227

Axolotls (urodele amphibians) can regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation.

The regenerated parts all work perfectly!

Preformism vs. Epigenesis Fully formed, miniature

versions of plants and animals exist at the beginning of creation

Antonie van Leeuwenhoek looked at a sperm cell through a microscope and found this to be “true”

Preformism vs. Epigenesis Plants and animals

develop through a sequence of steps

Cells differentiate (become more specialized) and tissues and organs form from these cells

Caspar Friedrich Wolff: complete lack of organization of tissues develop into highly organized structure

Differentiation is reversible!

Symmetric cell division

Asymmetric cell division

1. Self-renews 2. Differentiates

Progenitor cell

Stem cell Stem cell

SELF – RENEWAL

DIFFERENTIATION

DIFFERENTIATION

Where do we find stem cells? Early embryos

Adult tissues Skin, bone, blood Brain, retina, heart

NEW! Reprogrammed adult cells!

What is stem cell research? Understand more about development, aging,

disease Experimental model systems

Prevent or treat diseases and injuries Cell-based therapies Pharmaceutical development

Includes testing and drug delivery

Experimental model systemHeart muscle cells beating in a petri dish!

Videos by The Exploratorium

Stem cells for drug deliveryMore focused delivery, fewer side affects

NSCs injected

(no tumor)

NSCs injected (tumor)

Day 0 Day 7 Day 14

Shah et al. Dev Neurosci 2004

Bone marrow transplant:Example of adult stem cell-based therapy

Trachea transplantation:Example of adult stem cell-based tissue regeneration

Spinal cord injury:Example of embryonic stem cell-based therapy

Geron video: http://www.geron.com/grnopc1clearance/

Science is discovering the unknown

Stem cell field is still in its infancy Human embryonic stem cell research is a

decade old, adult stem cell research has 30-year head start

Holds hope for curing or improving treatments for 70+ diseases