1-Stem. Cells%20. -%20The% 20Present.ppt

Stem cells are a special type of cells that have two important properties. They are able to make more cells like themselves. That is, they self-renew. And they can become other cells that do different things in a process known as differentiation. Stem cells are found in almost all tissues of the body. And they are needed for the maintenance of tissue as well as for repair after injury.
Researchers are studying stem cells to see if they can help to:

Increase understanding of how diseases occur. By watching stem cells mature into cells in bones, heart muscle, nerves, and other organs and tissue, researchers may better understand how diseases and conditions develop.
Generate healthy cells to replace cells affected by disease (regenerative medicine). Stem cells can be guided into becoming specific cells that can be used in people to regenerate and repair tissues that have been damaged or affected by disease.

People who might benefit from stem cell therapies include those with leukemia, Hodgkin disease, non-Hodgkin lymphoma and some solid tumor cancers. Stem cell therapies also might benefit people who have aplastic anemia, immunodeficiencies and inherited conditions of metabolism.

Stem cells are being studied to treat type 1 diabetes, Parkinson's disease, amyotrophic lateral sclerosis, heart failure, osteoarthritis and other conditions.

Stem cells may have the potential to be grown to become new tissue for use in transplant and regenerative medicine. Researchers continue to advance the knowledge on stem cells and their applications in transplant and regenerative medicine.

Test new drugs for safety and effectiveness. Before giving drugs in development to people, researchers can use some types of stem cells to test the drugs for safety and quality. This type of testing may help assess drugs in development for toxicity to the heart.

New areas of study include the effectiveness of using human stem cells that have been programmed into tissue-specific cells to test new drugs. For the testing of new drugs to be accurate, the cells must be programmed to acquire properties of the type of cells targeted by the drug. Techniques to program cells into specific cells are under study.
There are several sources of stem cells:

Embryonic stem cells. These stem cells come from embryos that are 3 to 5 days old. At this stage, an embryo is called a blastocyst and has about 150 cells.

These are pluripotent (ploo-RIP-uh-tunt) stem cells, meaning they can divide into more stem cells or can become any type of cell in the body. This allows embryonic stem cells to be used to regenerate or repair diseased tissue and organs.

Adult stem cells. These stem cells are found in small numbers in most adult tissues, such as bone marrow or fat. Compared with embryonic stem cells, adult stem cells have a more limited ability to give rise to various cells of the body.
Adult cells altered to have properties of embryonic stem cells. Scientists have transformed regular adult cells in

1. Stem Cells and Diabetes
The Present

2. Background
Diabetes affects more people and causes
more deaths each year than breast
cancer and AIDS combined.
The American Diabetes Association
estimates that 16 million people, 5.9% of
the U.S. population, currently has some
type of diabetes.

3. What is diabetes?
group of diseases
abnormally high levels of glucose in the
blood
possible complications include blindness,
stroke, kidney failure, heart disease, poor
circulation, and amputation

4. Type 1 Diabetes
juvenile-onset
typically affects children and young adults
immune system attacks and destroys
beta cells (β cells) in the islets of
Langerhans of the pancreas that normally
produce insulin
glucose does not enter the cells and
therefore accumulates in the blood

5. Type 2 Diabetes
adult-onset diabetes
typically affects older, sedentary, and
overweight individuals with a family
history of diabetes
body cannot use insulin effectively
due to insulin resistance, glucose
accumulates in the blood

6. Role of Pancreas in Diabetes

7. What is insulin?
peptide hormone
synthesized within the β cells of the islets of
Langerhans located in the pancreas
affects metabolism and other body functions
causes cells in the liver, muscle, and fat
tissue to take up glucose from the
bloodstream

8. Role of Pancreas in Diabetes

9. Question:
In type I diabetics, is it possible to get
cells to produce insulin?
two possible sources of cells
•existing cells
•adult stem cells

10. What are adult stem cells?
They are:
undifferentiated cells that occur in
differentiated tissue
able to make identical copies of
themselves
able to yield specialized cell types of the
tissue from which they originated
do not replicate indefinitely in culture

11. Researchers are Investigating:
Is it possible to activate the differentiation
of adult stem cells present in the
pancreas in order to produce needed
insulin in type I diabetics?
What advantage/disadvantage would this
have over organ/islet transplantation or
insulin injection?

12. Researchers Would Need to Know:
Are there adult stem cells present in the
pancreas that differentiate into beta cells?
Are adult pancreatic beta cells formed by
self-duplication, stem cell differentiation,
or a combination of the two processes?

13. Mouse-Model Study
A pulse-chase experiment performed
by Professor Douglas Melton and his
team provides important information
about how beta cells are replaced.

14. Keep inmind that cells are
replaced by:
Adult stem cells
Mitotic division of existing cells
Combination of the two