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Stem Cells

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Importance of Stem Cell Research

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1998 - Researchers first extract stem cells from humanembryos

1999 - First Successful human transplant of insulin-makingcells from cadavers

2001 - President Bush restricts federal funding for embryonicstem-cell research

2002 - Juvenile Diabetes Research Foundation Internationalcreates $20 million fund-raising effort to support stem-cell research

2002 - California ok stem cell research

2004 - Harvard researchers grow stem cells from embryosusing private funding

2004 - Ballot measure for $3 Billion bond for stem cells

Stem Cell History

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Stem CellDefinition

A cell that has the ability tocontinuously divide anddifferentiate (develop) into various

other kind(s) of cells/tissues

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Stem Cell Characteristics

Blank cells (unspecialized)

Capable of dividing and renewing

themselves for long periods of time

(proliferation and renewal) Have the potential to give rise to

specialized cell types (differentiation)

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Kinds of Stem Cells

Stem cell

type Description Examples

TotipotentEach cell can develop

into a new individual

Cells from early(1-3 days)embryos

PluripotentCells can form any (over200) cell types

Some cells ofblastocyst (5 to 14days)

MultipotentCells differentiated, butcan form a number ofother tissues

Fetal tissue, cordblood, and adultstem cells

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This cellCan form the

Embryo and placenta

This cellCan just form the

embryo

Fully mature

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Kinds of Stem Cells

Embryonic stem cells

five to six-day-old embryo Tabula rasa

Embryonic germ cells

derived from the part of a human embryo or fetusthat will ultimately produce eggs or sperm(gametes).

Adult stem cells undifferentiated cells found among specialized or

differentiated cells in a tissue or organ after birth appear to have a more restricted ability to produce

different cell types and to self-renew.

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Pluripotent Stem Cellsmore potential to become any

type of cell

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Multipotent stem cells

Multipotentstem cellslimited in whatthe cells canbecome

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Embryonic Stem Cells

Mainly from IVF

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Sexual Reproduction

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Stages of Embryogenesis

blastocyst Blastocyst inner mass cells

8-cell stagecleavage

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Blastocyst Diagram

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Induced Pluripotent Stem Cells

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Bone Marrow

Found in spongy bone where blood cells form

Used to replace damaged or destroyed bone

marrow with healthy bone marrow stem cells. treat patients diagnosed with leukemia, aplastic

anemia, and lymphomas

Need a greater histological immunocompatibility

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Blood Cell Formation

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Umbilical cord stem cells

Also Known as Whartons Jelly

Adult stem cells of infant origin

Less invasive than bone marrow

Greater compatibility

Less expensive

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Umbilical cord stem cells

Three important functions:

1. Plasticity: Potential to changeinto other cell types like nervecells

2. Homing:To travel to the site oftissue damage

3. Engraftment:To unite with other

tissues

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Stem Cell Applications

Tissue repair- nerve, heart, muscle, organ,

skin Cancers Autoimmune diseases

- diabetes, rheumatoid arthritis,MS

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Tissue Repair

Regenerate spinal cord, hearttissue or any other major tissuein the body.

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http://www.youtube.com/watch?feature=player_embedded&v=eXO_ApjKPaI

Replace Skin

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Heart Disease

Adult bone marrow stem cellsinjected into the hearts are believedto improve cardiac function in

victims of heart failure or heartattack

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Leukemia and Cancer

Studies show leukemia patientstreated with stem cells emerge freeof disease.

Injections of stem cells have alsoreduces pancreatic cancers in somepatients.

Proliferation of white cells

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Rheumatoid Arthritis

Adult Stem Cells may be helpful injumpstarting repair of erodedcartilage.

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Type I Diabetes

Pancreatic cells do not produceinsulin

Embryonic Stems Cells might be

trained to become pancreatic isletscells needed to secrete insulin.

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Stem cells in the adult brain:

new researc reprogramm ng

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new researc reprogramm ngcells

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Technical Challenges

Source - Cell lines may havemutations.

Delivery to target areas

Prevention of rejection

Suppressing tumors

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Problems with Adult Stem Cells

Wh i S C ll R h S I

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Why is Stem Cell Research So Important

to All of Us?

Stem cells can replace diseased ordamaged cells

Stem cells allow us to studydevelopment and genetics

Stem cells can be used to test differentsubstances (drugs and chemicals)

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Why the Controversy Over Stem cells?

Embryonic Stem cells are derived from extra

blastocysts that would otherwise be discardedfollowing IVF.

Extracting stem cells destroys the developingblastocyst (embryo).

-Questions for Consideration-

Is an embryo a person?

Is it morally acceptable to use embryos forresearch?

When do we become human beings?

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