Stem Cells And Regenerative Medicine

Question 1

What are stem cells?

Answer 1

• Can differentiate into many different cell types
• Capable of self renewal via cell division
• Provide new cells as an organism grows and can replace damaged cells
• Targeted by researchers for their therapeutic potential
• Several different types of stem cells: embryonic, adult and induced pluripotent stem cells

Question 2

Where are the potential uses of stem cells?

Answer 2

• Blindness
• Wound healing
• Spinal cord injury
• Myocardial infarction
• Cancers

Question 3

What are the 3 main sources of stem cells?

Answer 3

• iPSC: Induced pluripotent
• ESCs: embryonic stem cells
• ASCs: adult stem cells
• Can be used for a variety of purposes such as:
• Disease modelling, Drug screening, Cell differentiation, 3D organoid models, Developmental biology, Cell replacement therapy

Question 4

Briefly describe embryonic stem cells

Answer 4

• Supply all the cells of the developing embryo
• Are pluripotent meaning they can differentiate into every type of cell
• Derived from embryos at the blastocyst stage, this is before implantation when the embryos are a few days old
• In vivo and in culture, these cells can proliferate via multiple rounds of cell division before differentiating
• Can give rise to cells from all 3 embryonic germ line, ectoderm, endoderm and mesoderm

Question 5

What does the ectoderm, mesoderm and endoderm produce?

Answer 5

• The ectoderm procures nervous and epithelial and sensory tissues
• The mesoderm produces skeletal and cardiac muscle, blood and connective tissue
• The endoderm produces Lungs, pancreas, stomach, liver and germ cells

Question 6

Briefly describe induced pluripotent cells

Answer 6

• Are made in the lab
• Scientists can take a normal tissue such as a skin or fat biopsy and reprogramme these cells by exposure to a specific set of pluripotency factors namely Oct4, Sox2, left4, CMC
• These produce pluripotent stem cells with similar characteristics to embryonic stem cells
• We can use these cells for cell therapy, repairing any mutations by gene editing techniques such as crispr-cas
• They can then be differentiated to healthy cells in vitro and transplanting them back into patients
• Since cels are specific to patient, there’s a reduced change of rejection

Question 7

How do stem cells go from totipotent to multi potent stem cells?

Answer 7

• Totipotent embryonic stem cells produce pluripotent embryonic stem cells
• These pluripotent stem cells are able to differentiate towards all 3 germ lines, Endoderm, mesoderm and ecoderm line
• These can then further divide to produce multi potent adult or tissue specific stem cells which can eventually differentiate into specialised cell types

Question 8

What do tissue specific stem cells require?

Answer 8

• Require specialised supportive micro environments call stem niches
• Niches are found at specific anatomical locations

Question 9

What do these niches do?

Answer 9

• Interact with stem cells to regulate thiosulphate
• May protect stem cells from depletion and the host from excessive stem cell proliferation

Question 10

List some specific features about stem cell niches

Answer 10

• Supporting Extracellular matrix molecules
• Neighbourimg niches
• Secreted soluble signalling factors (growth factors, cytokines)
• Physical parameters; Shear stress, tissue stiffness
• Environmental signals (metabolites, hypoxia, inflammation)

Question 11

Briefly describe the advantages and disadvantages of Embryonic Stem Cells

Answer 11

• Pluripotent: Almost unlimited growth potential, May differentiate into any kind of cell
• Unlimited numbers of cells due to high cell potency
• Very low probability of mutation induced damage in the DNA
• Higher risk of tumour creation
• Risk of being genetically different from the recipients cells, higher risk of rejection

Question 12

Briefly describe the advantages and disadvantages of Adult Stem Cells

Answer 12

• Compatible with recipients cells, low risk of rejection
• Less risk of tumour creation
• Higher probability of mutation, induced damage in the DNA, risk of diseases
• Unipotent, limited cell potency
• Limited numbers may be obtained

Question 13

Briefly describe the advantages and disadvantages of induced pluripotent Stem Cells

Answer 13

• Compatible with recipients cells, low risk of rejection
• Less growth potential than embryonic stem cells
• Less risk of tumour formation
• Rather limited numbers may be obtained
• Higher probability of mutation induced damage in the DNA, risk of diseases

Question 14

Describe how you would generate IPSC cells

Answer 14

• c-Myc promotes DNA replication and relaxes chromatin structure,
• Allows Oct3/4 to access its target genes.
• Sox2 and Klf4 also co-operate with Oct3/4 to activate target genes
• These encode transcription factors which establish the pluripotent transcription factor network
• Result in the activation of the epigenetic processes (more open chromatin) that establish the pluripotent epigenome
• iPS cells have a similar global gene expression profile to that of ES cells.

Question 15

What is stem cell tracking?

Answer 15

in vivo imaging can aid the development and clinical translation of cell-based therapeutics using non-invasive in vivo long-term cell tracking in the preclinical and clinical settings

Question 16

Briefly summarise these last 15 flash cards

Answer 16

• Stem cells are essential for replacing lost/damaged tissue due to their ability to self-renew via cell division and the ability to differentiate into many different cell types
• There are three main stem cell sources: adult (tissue specific stem cells), embryonic stem cells and induced pluripotent stem cells
• Scientists and doctors can harness the power of stem cells and genetic engineering to provide therapies to replace lost/damaged tissue