adult stem cells

Question 1

How were haematopoetic stem cells discovered?

Answer 1

• if you irradiate a mouse to stop its blood production it will die without further treatment
• injecting blood allows the mouse to survive with newly formed blood cells
• similar treatment is used in leukamias

Question 2

how are somatic cells replenished?

Answer 2

• stem cell differentiation
• division of differentiated cells

Question 3

what did pulse chase experiments show about the pancreas?

Answer 3

lacks stem cells as cell maintenance appears to be by beta-cell duplication

Question 4

What is wound healing?

Answer 4

• bodys response to stop further tissue damage
• not regeneration
• stopping the bleeding, preventing infection etc

Question 5

What is regeneration?

Answer 5

• can go hand in hand with wound healing
• tissues such as the liver regenerate more efficiently due to being rich in stem cells
• a wound in muscle will take longer to regenerate

Question 6

what are the issues with mammalian regeneration?

Answer 6

• cancer risk
• lost or altered genetic programme
• smaller stem cell pool

Question 7

how does lost or altered genetic programme affect our ability to regenerate tissues?

Answer 7

• regenerative capacity is reduced as you go up the evolutionary scale
• we dont have the appropriate signals for regeneration (CD59)

Question 8

How do Newt limbs know how to regenerate?

Answer 8

Regeneration information is graded along the newt limb. different parts of the limb can be created in the correct order due to CD59 being expressed in high concentrations at the elbow and decreasing as you reach the toes - guides the cells to form the correct part of the limb

Question 9

How does our stem cell pool affect our ability to regenerate?

Answer 9

• smaller stem cell pool
• stem cells are depleted with age in the muscle
• but bone marrow cells along with IGF-1 can support the regeneration of aged muscle tissue

Question 10

What are the functions of cancer stem cells

Answer 10

• source of malignant cells in a primary tumour
• can act as a reservoir of drug-resistant cells
• give rise to distance metastases
• leukemias often come from stem cell mutations
• in other cancers such as breast, CSCs are associated with dedifferentiation