Stem cells 4/11/19
Stem cell = relatively unspecialized that can produce 2 identical daughter cells by a single division
- Also can produce 2 more specialized daughter cells – which can be differentiated
further/one cell of each type
Every organ has ‘niche’ of stem cells for several for regeneration of cells. Stem cells = bodies’ natural
repair mech.
Potency = ability of a cell to differentiate into other types
Stem cells can be self-renewed or differentiated
- Stem cell divides (renews) into 2 same stem cells (symmetrical cell division) – daughter cells
= identical to parental call – same potency for self-renewal
If the body need more of a specific cell (e.g. – cardiac/liver/neural) – 2 ways this occurs:
- Asymmetric cell division – One daughter cell = same as parental cell, other = committed cell
– (cardiac/liver/neural etc.)
- Symmetric SC commitment – Stem cell commits to specified cells during cell division – lose
stem cell
Embryo = first stem cell in development
- Body = formed from single cell (oocyte – immature egg cell) – via cell division, differentiation,
migration and apoptosis.
Morula = made of identical cells
3 germ layers:
- Ectoderm = neural cells
- Mesoderm = cardiac cells
- Endoderm = lungs, liver
Human embryos for research are from donated blastocytes (Human embryotic stem cells = hES)
- Inner mass cells = separated from rest of blastocyte
- Placed on feeder cells – grows embryotic sc
Cells can be grown rapidly – very important for medicine
- Any type of cell can be produced
- Cells need to be specified – E.g. – Pancreatic β-cells – for insulin
, hES = HLA antigens – tells body the cells = self
- Non-self cells = different HLA profile = recognised as non-self and killed
- Same HLA typing needed for donating to different people
Totipotent = self-renew, result in placenta and embryo – all cells
Pluripotent = any cells (except placenta)
Ethics of SC:
- Involves destruction of embryo – religious and ethical disagreement
- However – embryos = unwanted – so not too bad
- Informed consent
Several clinical trials – using hES – type I Diabetes = very widely researched
iPS Cells:
- Process of de-differentiation
- Cell can come from patient (in the case of medicine)
- iPS need genetic manipulation – but currently unsafe
Multipotent stem cells = specialised (adult stem cells)
Bone marrow transplantation = example of cell therapy
- Hematopoietic SC (HSC)= powerful – several diseases affect WBC – potentially be treated by
HSC
Mesenchymal Stem cells = in placenta, bone marrow, heart, muscles and several other sources – used
to treat bone diseases – e.g. – cartilage injury
- Mesenchymal stem cells secrete anti-inflammatory areas – can ‘dampen’ down areas of
inflammation
- E.g. = stroke – excess bleeding causes inflammation – drugs often contain anti-inflammatorys
– potential for mesenchymal cells
- For cartilage injury – cartilage producing cells = grown from mesenchymal sc – (from patients’
bone marrow) – grown and specified – put into gel and back into body – regeneration of
cartilage.
Massive increase in clinal trials involving mesenchymal stem cells over the years
Cell differentiation = in vivo or in vitro
- In vivo = inside the body
- In vitro = outside the body
Stem cell = relatively unspecialized that can produce 2 identical daughter cells by a single division
- Also can produce 2 more specialized daughter cells – which can be differentiated
further/one cell of each type
Every organ has ‘niche’ of stem cells for several for regeneration of cells. Stem cells = bodies’ natural
repair mech.
Potency = ability of a cell to differentiate into other types
Stem cells can be self-renewed or differentiated
- Stem cell divides (renews) into 2 same stem cells (symmetrical cell division) – daughter cells
= identical to parental call – same potency for self-renewal
If the body need more of a specific cell (e.g. – cardiac/liver/neural) – 2 ways this occurs:
- Asymmetric cell division – One daughter cell = same as parental cell, other = committed cell
– (cardiac/liver/neural etc.)
- Symmetric SC commitment – Stem cell commits to specified cells during cell division – lose
stem cell
Embryo = first stem cell in development
- Body = formed from single cell (oocyte – immature egg cell) – via cell division, differentiation,
migration and apoptosis.
Morula = made of identical cells
3 germ layers:
- Ectoderm = neural cells
- Mesoderm = cardiac cells
- Endoderm = lungs, liver
Human embryos for research are from donated blastocytes (Human embryotic stem cells = hES)
- Inner mass cells = separated from rest of blastocyte
- Placed on feeder cells – grows embryotic sc
Cells can be grown rapidly – very important for medicine
- Any type of cell can be produced
- Cells need to be specified – E.g. – Pancreatic β-cells – for insulin
, hES = HLA antigens – tells body the cells = self
- Non-self cells = different HLA profile = recognised as non-self and killed
- Same HLA typing needed for donating to different people
Totipotent = self-renew, result in placenta and embryo – all cells
Pluripotent = any cells (except placenta)
Ethics of SC:
- Involves destruction of embryo – religious and ethical disagreement
- However – embryos = unwanted – so not too bad
- Informed consent
Several clinical trials – using hES – type I Diabetes = very widely researched
iPS Cells:
- Process of de-differentiation
- Cell can come from patient (in the case of medicine)
- iPS need genetic manipulation – but currently unsafe
Multipotent stem cells = specialised (adult stem cells)
Bone marrow transplantation = example of cell therapy
- Hematopoietic SC (HSC)= powerful – several diseases affect WBC – potentially be treated by
HSC
Mesenchymal Stem cells = in placenta, bone marrow, heart, muscles and several other sources – used
to treat bone diseases – e.g. – cartilage injury
- Mesenchymal stem cells secrete anti-inflammatory areas – can ‘dampen’ down areas of
inflammation
- E.g. = stroke – excess bleeding causes inflammation – drugs often contain anti-inflammatorys
– potential for mesenchymal cells
- For cartilage injury – cartilage producing cells = grown from mesenchymal sc – (from patients’
bone marrow) – grown and specified – put into gel and back into body – regeneration of
cartilage.
Massive increase in clinal trials involving mesenchymal stem cells over the years
Cell differentiation = in vivo or in vitro
- In vivo = inside the body
- In vitro = outside the body
