Stem CellsStem Cells

What is a stem cell?What is a stem cell?

Where do stem cells Where do stem cells come from?come from?

What is a stem cell?What is a stem cell?

A stem cell is a cell that:A stem cell is a cell that: Is unspecializedIs unspecialized Is capable of dividing and Is capable of dividing and

renewing itself for a long renewing itself for a long period of timeperiod of time

Can give rise to specialized Can give rise to specialized cellscells

There are 3 types of stem There are 3 types of stem cellscells

1.1. TotipotentTotipotent Formed from sperm and egg, has Formed from sperm and egg, has

the potential to make every cell in the potential to make every cell in the body and the placenta. the body and the placenta.

This cell exists for only 5 days This cell exists for only 5 days following fertilizationfollowing fertilization

2. 2. PluripotentPluripotent Found between 5-10 days of embryo Found between 5-10 days of embryo

growth, the embryo is now called a growth, the embryo is now called a blastocystblastocyst

These cells have the potential to create These cells have the potential to create every cell in the bodyevery cell in the body

These cells can be isolated from the inner These cells can be isolated from the inner cell mass (30 cells) of the of the blastocystcell mass (30 cells) of the of the blastocyst

These are called embryonic stem cells and These are called embryonic stem cells and are used for stem cell researchare used for stem cell research

Picture of BlastocystPicture of Blastocyst

How big is a blastocyst?How big is a blastocyst?

3. 3. MultipotentMultipotent Called Adult Stem CellsCalled Adult Stem Cells Can become a limited number of Can become a limited number of

other cellsother cells Occur in limited numbersOccur in limited numbers May contain DNA damage from May contain DNA damage from

aging, radiation, sunlight, toxins and aging, radiation, sunlight, toxins and random mutations that occurred random mutations that occurred during lifeduring life

Embryonic v. Adult Stem Embryonic v. Adult Stem CellsCells

EmbryoEmbryo Come from embryos Come from embryos

that are fertilized in that are fertilized in petri dishes to be used petri dishes to be used for couples that for couples that cannot conceive, there cannot conceive, there are 40,000+ being are 40,000+ being stored currentlystored currently

Could also be created Could also be created by joining egg/sperm by joining egg/sperm

Can become every cell Can become every cell type found in the bodytype found in the body

AdultAdult Come from babies, Come from babies,

umbilical cords, adultsumbilical cords, adults Can become some cell Can become some cell

typestypes Found in some body Found in some body

tissues – brain, bone tissues – brain, bone marrow, blood, eye, marrow, blood, eye, fat, muscle, skin and fat, muscle, skin and liverliver

First Stem CellsFirst Stem Cells

The first successful stem cells were The first successful stem cells were reported in November of 1998 by a reported in November of 1998 by a research at the Univ. of Wisconsin research at the Univ. of Wisconsin who removed the cells from spare who removed the cells from spare embryos at a fertility clinic. He was embryos at a fertility clinic. He was then able to have these stem cells then able to have these stem cells kept alive without specializing in a kept alive without specializing in a petri dish. petri dish.

Stem Cell LinesStem Cell Lines

After the stem cells are harvested After the stem cells are harvested they must be kept healthy and live they must be kept healthy and live for many generations without for many generations without differentiating into specialized cells. differentiating into specialized cells.

This is called a stem cell line.This is called a stem cell line. Cells are then taken from these and Cells are then taken from these and

used for various research projects. used for various research projects.

What can embryonic stem cells What can embryonic stem cells be used for?be used for?

Learn how a cell becomes specializedLearn how a cell becomes specialized Be used to test new drugs – decreases Be used to test new drugs – decreases

amount of animal testing, cheaper, amount of animal testing, cheaper, faster, and safer for human trials. faster, and safer for human trials.

Study causes of disease – lead to Study causes of disease – lead to possible treatments.possible treatments.

Study how diseases spread – ex: Bird fluStudy how diseases spread – ex: Bird flu

Repair damaged cells – paralysis and Repair damaged cells – paralysis and spinal cord damage. spinal cord damage.

Cure diseases – diabetes, heart Cure diseases – diabetes, heart disease, parkinson’s disease, disease, parkinson’s disease, alzheimer’s disease, genetic diseases alzheimer’s disease, genetic diseases etc. etc.

Grow into new human organsGrow into new human organs

The controversyThe controversy

Embryonic stem cells are Embryonic stem cells are controversial because to obtain them controversial because to obtain them they must destroy the embryo.they must destroy the embryo.

People question where the embryos People question where the embryos will come from, how many embryos will come from, how many embryos will have to be destroyed, what are will have to be destroyed, what are the rights of the embryo?the rights of the embryo?

What can adult stem cells be What can adult stem cells be used for?used for?

Have been used successfully for the Have been used successfully for the following:following: Heart disease – inject new cells into heart Heart disease – inject new cells into heart

after heart attacks to replace damaged after heart attacks to replace damaged cellscells

Leukemia/Cancer – use stem cells from Leukemia/Cancer – use stem cells from bone marrowbone marrow

Rheumatoid arthritis – make new cartilageRheumatoid arthritis – make new cartilage Parkinson’s disease – make new cellsParkinson’s disease – make new cells Type I diabetes – make new pancreas cellsType I diabetes – make new pancreas cells

Past PoliciesPast Policies On August 9On August 9thth, 2001 President Bush , 2001 President Bush

announced that federal funds can be announced that federal funds can be used for human embryo research IF:used for human embryo research IF: The cells were harvested from the embryo The cells were harvested from the embryo

before this datebefore this date The embryo was created for reproductive The embryo was created for reproductive

purposes and was no longer neededpurposes and was no longer needed The embryo was donated and the donors The embryo was donated and the donors

consented and did not receive any moneyconsented and did not receive any money

What did that mean?What did that mean?

Any stem cell lines that were already Any stem cell lines that were already in progress could be used but no in progress could be used but no stem cells could be harvested if the stem cells could be harvested if the project receives any federal money.project receives any federal money.

Research can be done with private or Research can be done with private or state funding – exs: California, state funding – exs: California, HarvardHarvard

New PolicyNew Policy

On March 9On March 9thth, 2009 President Obama , 2009 President Obama announced that federal money would announced that federal money would be used to continue stem cell be used to continue stem cell research. research.

This lifted many of the bans that had This lifted many of the bans that had been in place previously and opened been in place previously and opened up stem cell research to many more up stem cell research to many more scientists and institutions. scientists and institutions.

President Obama 3/09President Obama 3/09

“I will ensure that my “I will ensure that my administration never opens administration never opens

the door to cloning for the door to cloning for human reproduction.”human reproduction.”

“It is dangerous, profoundly “It is dangerous, profoundly wrong and has no place in wrong and has no place in

our society or any society.” our society or any society.”

Ethical DebateEthical Debate

Are the rights of the embryo more or Are the rights of the embryo more or less important than the people who less important than the people who could benefit from the research? could benefit from the research?

Some reports estimate that 100 Some reports estimate that 100 million Americans suffer from million Americans suffer from diseases that may be cured using diseases that may be cured using stem cell research.stem cell research.