Standing on the Threshold: The Promise of Stem Cell Science
Douglas A. Melton, PhD. Xander University Professor of Stem Cell and Regenerative Biology
stem cells to replace tissues
stem cells to screen for drugs that stop degenerative diseases
stem cells for healthy aging
Differentiated Cells Are Not Static:
cells are continually being renewed
intestine cells last a few days
blood cells last up to ten weeks
pancreas cells live for months to years
brain cells are nearly permanent
2 Essential Properties of Stem Cells:
self replicate (renew or regenerate themselves) and give rise to specialized cells
Human Embryotic Stem Cells
Ectoderm: skin, brain, nerves
Mesoderm: blood, heart, kidney, muscle, bone
Endoderm: lung, liver, stomach, pancreas (size of banana), intestine
Making insulin- producing cells from stem cells:
ES/IPS———-> Endoderm————> Pancreas———–> Endocrine———-> Insulin
While our nation is suffering from large financial defects, we’re also suffering from large beta cell defects. There are not enough beta cells in the population to manage their glucose control leading to the epidemic of Type 2 Diabetes.
Making enough insulin-producing cells for a patient: 1 billion needed, nearly there……..
Making Human Heart Cells:
human embryonic stem cells—-> specialized cells——>reconstructing human heart cells
Making stem cells from skin: induced- pluripotent stem cells.
skin cells—–> add DNA or RNA encoding reprogramming factors—–> patient specific stem cells
Degenerative Diseases (stem cells can reconstruct the neurons and cells needed):
Alzheimer’s: forebrain neurons
Parkinson’s: midbrain neurons
ALS: motor neurons
Cardiovascular Diseases: cardiac muscle cells
Type 1 Diabetes: Pancreatic Beta Cells
Screening for drugs that increase motor neuron life:
goal: to define a drug to treatment that will slow the degeneration
Experiment: old and young mice must share a blood stream O=OLD Y=YOUNG
When one is injured what happens?
OY + young repairs at its own healthy rate
YY + a lot of red, new muscle cells
OO – can not repair
YO + Old repairs at Young rate
1. Young blood improves muscle’s regeneration in old mice. Young blood contains factors that stimulate muscles stem cells in old animals. Old mouse’s blood is not poisoning the repairs (<—OY).
2. Young blood reduces cardiac size and improves elasticity in old mice.
3.Young blood enhances remyleination in old mice (brain).