STEM CELLS: WHAT ARE THESE THINGS? A informative, scientific, and ethical approach to stem cell technology. Created by: April and Kate

First of all, a definition Stem Cell-An unspecialized cell from an embryo, fetus, or adult. –They serve as a repair system for the body –They have the ability to keep dividing without limit as long as the animal lives or the line is kept alive in the lab.

Unique Characteristics of Stem Cells Like the definition, they are unspecialized cells that can divide themselves. Under certain conditions, these stem cells can become specialized cells that perform specific functions in the body.

There are three classes of Stem Cells Totipotent-A cell that has total potential, or the ability to form all the different types of body cells. These are found in fertilized eggs. Multipotent- Cells that can only specialize into a few cell types. Pluripotent-Can become all types of body cells, except the cells needed to become a fetus.

More Definitions Embryonic Stem Cell –A group of cells from the inner cell mass that are retrieved from a blastocyst (4-5 day embryo). After being retrieved, these cells can be cultured into embryonic stem cells in a lab. –These cells are not themselves embryos, and new evidence is concluding that these cells act differently in the lab as they would in a developing embryo.

More Definitions Embryonic Germ Cell –These are derived from fetal tissue –Isolated from the primordial germ cells of a 5-10 week old fetus –These are pluripotent just like Embryonic Stem Cells, but are not identical to embryonic stem cells.

More Definitions Adult Stem Cells – unspecialized cells that are found in the midst of specialized tissue. –These cells renew themselves, and become specialized to change into the type of cell that surrounds it. –These types of cells are rare in adults.

Yeah, More definitions Differentiation –The process where unspecialized cells become a specific type of cell that makes up the human body. (ex. Blood, Nerve, Muscle, etc.) Plasticity –The ability of an adult stem cell found in one type of tissue to specialize into another type of tissue

What are scientists researching? Along with researching potential benefits of stem cells (which we will discuss later), scientists are concentrating on figuring out how exactly stem cells work.

What questions do scientists have? –Questions that still need answered: Why can embryonic stem cells proliferate for up to a year in the lab, while adult stem cells cannot? What is in living organisms that regulate stem cell proliferation and self-renewal? –This info would help scientists understand how to grow stem cells more efficiently in the lab

Differentiation Scientists are researching the mechanics of how cells differentiate They do know that external factors cause differentiation to occur. External conditions like: –Chemicals expelled by other cells –Physical Contact with Neighbor cells –Certain molecules in the stem cells microenvironment.

Differentiation Types So far, there are three types of stem cells, and they can differentiate into many types of cells

Hemetopoietic Stem Cells These can differentiate into three major types of brain cells, cardiac muscle cells, liver, and skeletal muscle cells

Bone Marrow Stromal Cells These can form cardiac muscle cells and skeletal muscle cells

Brain Stem Cells These can form blood and skeletal cells.

Adult Stem Cells Blood-forming stem cells in bone marrow (also called hemetopoietic sc) are the only type of SC that are commonly used to treat human diseases Doctors have been using bone marrow transplants for over 40 years. More advanced treatments have been used on an experimental basis to treat leukemia, lymphoma, and several inherited blood disorders.

Adult Stem Cell ?’s How many kinds and what tissues do these cells live in? What are the sources of these cells? Do they normally have plasticity or just when they are manipulated in the lab? Is is possible to manipulate these cells to enhance proliferation?

Adult SC Limitations Adult stem cells are present in small quantities They are difficult to isolate and purify They may contain more DNA abnormalities caused by sunlight, toxins, and spontaneous DNA errors that occur throughout life These limitations may limit Adult Stem Cell usefulness

ADULT VS. EMBRYONIC The two differ in the type of cells that they can become, or the plasticity of the cells –Adult-generally limited to the tissue of origin –Embryonic-has the potential to become all cell types

ADULT VS. EMBRYONIC Embryonic-Can easily be grown in cultures Adult-Scientists are still unsure about how to expand AS cells because they are so rare Why is this important?-Large #’s of cells are necessary for cell therapies to be successful

ADULT VS. EMBRYONIC Extracting Adult Stem Cells from a patient, culturing those cells, and then implanting them in the same patient would eliminate rejection risks It is unsure of the rejection risks of Embryonic Stem Cells

Potential Uses Embryonic Stem Cells –To understand events that occur during human development –Some of the most serious conditions happen because of faulty differentiation. –If we can understand the HOW’S, then we can begin to understand how to fix the problems

Potential Uses Stem cells could be used to test new drugs (no more human guinea pigs) The Generation of Cells And Tissues (maybe with no rejection) “Stem cells directed to differentiate into specific cell types offer the possibility of a renewable source of replacement cells and tissues to treat diseases like Parkinson’s and Alzheimer’s, spinal cord injury, stroke, burns, and heart disease.”

Research Embryonic –Have only been able to experiment with them since 1998 –Federal Funds have only been available since Aug. 2001, and only with restrictions SC lines have to come 1 of 22 lines specified by the government These lines had to come from embryos created prior to 2001 without the capability of human development, and with parental consent

Research What research is the best to pursue? –The National Health institute believes that “it is important to simultaneously pursue all lines of research and search for the very best sources of these cells” –Also, the NIH says, “Human Embryonic Stem Cells are thought to have much greater development potential than adult Stem Cells

Embryonic SC Ethics Before Researching ES Cells, one must ask, “Does the End Justify the Means?” The end=Scientists hope to achieve the relief of suffering. This appears to be a worthy end and is not the question in dispute.

Embryonic SC Ethics The question is… Does the potential gains from ES cell make is ok to consume donated embryos? –ES cell research would use donated embryos that would never enter a uterus –This question can’t be answered like many other problems can History doesn’t give us any answers Science can’t answer questions about the soul or the spirit We are left to our own moral reasoning, which varies from person to person

Embryonic Stem Cell ?’s For embryos formed in a lab frozen for the purpose of in-vitro: –Is it ethical to use these embryos? –What if the parents give consent? –What happens to these embryos if they aren’t used in stem Cell research? –Is science just going too far? –If ES cell research is going too far, does that also mean that in-vitro is going too far?

What about Umbilical Cord Stem Cells Currently, many hospitals (like St. Mary’s in g-burg) are mandated to ask pregnant women if they are interested in donating their umbilical cord blood for the purpose of extracting stem cells.

What about Umbilical Cord Stem Cells? Women who consent are put through a rigorous questionnaire (see packet) and after the birth of their child, the cord blood is taken.

What is it used for? It would be really nice if the stem cells obtained from Umbilical Cord blood could be used in place of embryonic stem cells, therefore eliminating the ethical problem BUT… Umbilical Cord blood is an abundant source of hemetopoietic stem cells. There does not appear to be a difference between Adult Stem cells obtained from bone marrow.

Umbilical Cord Stem Cells Basically, Umbilical Cord Blood contains the same type of stem cells as any other part of an adult, but just in a more abundant amount, although still not near the amount needed for cell therapies.

In the News A new international stem cell bank has recently opened in South Korea (Reported by BBC on Oct. 19, 2005) –It’s aim is to produce around 100 embryonic stem cell lines per year –The rest of the world seems to be continuing research into ES cell potential, so should the US consider revising its position?

References The National Health Institute Website ( “monitoring stem cell research” A Report of the President’s Council on Bioethics. January Cryobanks International, INC. Public Cord Blood Donation Program. Copyright 2003.