Stem Cells Flashcards
(34 cards)
What are the key characteristics of stem cells
Self renew (Highly proliferative)
Differentiate into specialised cells
What is the process of cell differentiation
The process by which stem cell becomes specialised due to changes in gene expression
Define the levels of stem cell potency
Totipotent: All cell types including embryonic support cells.
Pluripotent: Nearly all cells, excluding embryonic support cells.
Multipotent: Multiple, but limited cell types.
Bipotent: Two specific cell types.
Unipotent: One specific cell type.
Where are embryonic stem cells sourced from?
The inner cell mass of the blastocyst
What are the 3 germ layers formed during gastrulation?
Ectoderm: skin, brain, nervous system
Mesoderm: muscles, circulatory system
Endoderm: Gut lining, internal organs
Explain the advantages of ESCs in research
High self renewal capacity and pluripotency
What are the disadvantages of ESCs?
Immune rejection and ethical issues relating to the destruction of an embryo
What cell types do MSCs definitely differentiate in to?
Adipocytes
Chondrocytes
Osteoblasts
What niche do hematopoietic stem cells occupy?
Vascular regions of bone marrow
Where are mesenchymal stem cells found?
Stromal regions of bone marrow and other tissues
How are iPSCs created
By reprogramming adult somatic cells (e.g. from skin or peripheral blood) using Yamanaka factors to induce pluripotency
What are the Yamanaka factors
Oct 4
Sox
Klf4
c-Myc
How are iPSCs made
- Selection of cell source
- Reprogramming into iPSCs
- Gene editing (correct mutations etc.)
- Culture and expansion
- Characterisation and quality control
List the advantages of using iPSCs
Pluripotent
Highly proliferative
Can be autologous
List some disadvantages of iPSCs
Safety concerns (teratoma risk)
Expensive
Technically complex
Explain the purpose Geron’s spinal cord trial
hES cell–derived oligodendrocyte progenitor cells for remyelination and nerve growth-stimulation.
What were the reasons for the Geron trial stopping?
Purity/ predictability concerns
Teratoma fears (but were cysts)
Finances - ran out of money :(
Explain a use of MSCs in clinical trials
ixmyelocel-T: Autologous MSC product tested for ischemic heart disease
Which factors negatively affect the validity of MSC-based therapy
Donor variance
In vitro expansion
Immunogenicity
Senescence
Cryopreservation
What are 2 ways MCSs are useful in tissue engineering
Tissue regeneration
Paracrine functions
What are the paracrine functions of MSCs
Reduce inflammation (anti-inflammatory factors)
Modulate immune cells
Fight apoptosis and fibrosis
Improve angiogenesis
Regenerate tissue
How are hemopoietic stem cells used to treat lymphoma/ leukemia
Collect donor cells via peripheral blood stem cell collection or bone marrow donation.
Patient receives high dose chemo to kill cancer cells and weaken the immune system (prevents rejection)
Inject donor cells into patient which travel to the bone marrow.
What are some applications of iPSCs in regenerative medicine
Retinal pigment epithelial cells: macular degeneration
Dopaminergic neurons: To replace lost cells and restore motor function in Parkinson’s disease.
Cardiomyocytes: Integrate into cardiac tissue to restore heart function.
What is a teratoma and why is this a concern for iPSCs?
Benign cancer which can damage surrounding tissue and has the potential to become malignant. This is due to genomic instability due to induced pluripotency.
