Stem Cells

The Biotech issue that may no longer be an issue.

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What are stem cells?

“Blank slate” or unspecialized “Blank slate” or unspecialized

Under right conditions, can become any cell type in our body.

Under right conditions, can become any cell type in our body.

Where do stem cells come from?Two general sources:Two general sources:

Embryonic Stem Cells (ESC) Adult Stem Cells (ASC)

Embryonic Stem Cells (ESC) Adult Stem Cells (ASC)

Human Development

Zygote: fertilized eggZygote: fertilized egg

Cells divide. 5 – 6 days later, blastocyst implants in uterine lining.

Cells divide. 5 – 6 days later, blastocyst implants in uterine lining.

Cell division video

– internet link

Cell division video

– internet linkCell division video

– intranet link

Cell division video

– intranet link

Blastocyst has two parts – Blastocyst has two parts – trophoblasttrophoblast (will become placenta) (will become placenta) and and inner cell mass inner cell mass (ICM) which (ICM) which are embryonic stem cells (ESC)are embryonic stem cells (ESC)

Ready to implant in uterine liningReady to implant in uterine lining

http://en.wikipedia.org/wiki/Blastocyststemcells.nih.gov/info/ scireport/appendixA.asp

Human Development

Human Development

Totipotent: Able to become all types of cells. (Ex. zygote)

Totipotent: Able to become all types of cells. (Ex. zygote)

Pluripotent: Able to become most types of cells. (Ex. Inner Cell Mass can become everything except placenta)

Pluripotent: Able to become most types of cells. (Ex. Inner Cell Mass can become everything except placenta)

Multipotent: Able to become some types of cells. (Ex. Bone marrow cells can become different types of white blood cells, but cannot become muscle or nerve cells)

Multipotent: Able to become some types of cells. (Ex. Bone marrow cells can become different types of white blood cells, but cannot become muscle or nerve cells)

Human DevelopmentUndifferentiated: Have not decided to become a type

of cell yet. (Ex. Zygote)Undifferentiated: Have not decided to become a type

of cell yet. (Ex. Zygote)

Differentiate: Decide to become a cell type. Happens after blastocyst stage. (Ex. When placed in a dish, ESC’s will spontaneously differentiate into . . . Video – internet; video - intranet)

Differentiate: Decide to become a cell type. Happens after blastocyst stage. (Ex. When placed in a dish, ESC’s will spontaneously differentiate into . . . Video – internet; video - intranet)

Embryonic Stem Cells

What signals did they receive to become these types?What signals did they receive to become these types?

If we can figure out how to cause the entire dish of cells to become one type of cell . . .

If we can figure out how to cause the entire dish of cells to become one type of cell . . .

Human Development

A model for understanding human organ and tissue function and development

Prevention of birth defects and cell-based diseases

Drug Screening

Trials conducted on pure populations of cells in vitro, before administering them in vivo

Regenerative Medicine

“Holy Grail”

Human embryonic stem cells can provide a potentially unlimited source of cells for transplantation therapies

U.W. Researchers: Dan Kaufman, M.D., Ph.D. and Dong Chen, M.D., Ph.D.

• Bone marrow transplants offer a cure for many patients with leukemia, lymphoma, and multiple myeloma.

• Unfortunately, because of lack of appropriate donors, only about one-third of patients who require bone marrow from an unrelated, matched donor can actually obtain a transplant.

Embryonic Stem Cells to Blood CellsEmbryonic Stem Cells to Blood Cells

Parkinson’s disease is caused by the death of a specific type of neuron (dopaminergic neurons). 1.5 million people affected in the U.S. Fetal tissue transplants have been successful, but the source of tissue is inadequate.

DifferentiateDifferentiate

Stem Cells to Neuronal CellsStem Cells to Neuronal Cells

UW Researchers: Su-Chun Zhang, M.D., Ph.D & Clive Svendsen, Ph.D

Pancreatic -Cell Differentiation of ES Cells

Juvenile onset diabetes is caused by the death of specific pancreatic cells (islet cells). 1 million people affected in the U.S. More than 15% of U.S.Health Care dollars are spent in taking care of these patients. The transplantation of pancreatic islet cells has been successful, but the source of cells in inadequate.

Juvenile Onset Diabetes UW Researcher: Jon Odorico, M.D.

DifferentiateDifferentiate

Stem Cells to Bone CellsStem Cells to Bone Cells

Bone Cartilage

1. Post Menopausal Osteoporosis, Age-related Osteoporosis

2. Sports Injuries

3. Joint Replacements/ Surgical repair

4. Developmental bone defects

Embryonic Stem Cells

All of this work requires being able to grow ESC’s without differentiating unless you tell them to do so.

All of this work requires being able to grow ESC’s without differentiating unless you tell them to do so.

Dr. James Thomson – discovered how to grow ESC’s without differentiation in 1998.

Dr. James Thomson – discovered how to grow ESC’s without differentiation in 1998.

Where do ESC’s come from?

IVF – in vitro fertilizationIVF – in vitro fertilization

In 2004, 29% of embryos were destroyed while 41% were donated to ESC research.

In 2004, 29% of embryos were destroyed while 41% were donated to ESC research.

Once ICM is removed, blastocyst is no longer viable.

Once ICM is removed, blastocyst is no longer viable.

Video – internet; video - intranetVideo – internet; video - intranet

ESC’s limitations

Destruction of blastocyst - videoDestruction of blastocyst - video

ESC’s limitations

Destruction of blastocystDestruction of blastocyst

Tissue is not yours which can lead to immune system rejection

Tissue is not yours which can lead to immune system rejection

Solution? Therapeutic CloningSolution? Therapeutic Cloning

Dedifferentiate: return to an undecided or undifferentated state.

Dedifferentiate: return to an undecided or undifferentated state.

Adult Stem Cells (ASC)

ASC’s

All types are multipotent.All types are multipotent.

SourcesSources

- Umbilical cord

- Bone marrow

- Adipose tissue (fat)

- skin

- Umbilical cord

- Bone marrow

- Adipose tissue (fat)

- skin

Stem Cell Summary VideoAdult stem cells- 3:20 – 5:40Stem Cell Summary VideoAdult stem cells- 3:20 – 5:40

ASC’s

Uses: - Leukemia (bone

marrow)

- Skin grafts

Uses: - Leukemia (bone

marrow)

- Skin grafts

ASC’s

Limitations: - Multipotent

- Hard to find

Limitations: - Multipotent

- Hard to find

iPS CellsInduced pluripotent stem cells- 2007, Dr. James Thomson- 4 genes added to differentiated cells (e.g. skin

cells)- Cells dedifferentiate and become stem cells- No blastocyst is produced

Induced pluripotent stem cells- 2007, Dr. James Thomson- 4 genes added to differentiated cells (e.g. skin

cells)- Cells dedifferentiate and become stem cells- No blastocyst is produced

Sciencenow iPS VideoHeart cells from skin

cells

Sciencenow iPS VideoHeart cells from skin

cells