Stem Cells Flashcards
type of stem cells
- totipotent (zygotic)
- dydx into all cell types that make up an entire organism including extraembryonic tissues like placenta
- found in fertilised egg to 8 cell stage (zygotic SC) - pluripotent (embryonic)
- dydx into all cell types that make up an organism except extraembryonic tissue
- found in inner cell mass of blastocyst - multipotent (adult)
- develop into a limited and related range of cell types and tissues
- found in haematopoietic SC in bone marrow
argument against using embryonic SC (HSBC)
- some believe embryo has the status of human being as it has the potential to become one -> tantamount to murder
- extracting SC from embryo to make replacement body cells is treating embryo as a source of spare parts
- claims of benefits of SC research is overrated -> few examples of success in medical applications
- possibility of unforeseen consequences in treated patient like possible risks of tumour formation, immunological reactions, unexpected behaviour of cells and unknown long term health effects
argument for using embryonic SC
- embryos are not equivalent to human life
- some believe life only begins when a heartbeat develops or when the brain begins developing
- can potentially treat a wide range of diseases as they have the potentially to grow indefinitely in a laboratory environment & can dydx into almost all types of bodily tissues
- unethical not to use established protocols on ESC research to further research and help relieve human suffering
advantages of using own injected SC instead of complete organ transfer [3]
- will not cause immune system to be stimulated as there are no foreign cells -> no need to use immunosuppressants drugs
- no need to source for suitable donor -> save time and money
- SC are capable of cell proliferation and self-renewal -> required cells can grow in large quantity
what are iPSC (induced pluripotent SC)?
- pluripotent SC that are generated directly from adult somatic cells (non-pluripotent)
- non-pluripotent cells can be induced to become pluripotent
advantages of iPSCs [6]
- does not generate and destroy any embryos
- may enable an additional reproductive technology that generate sex cells -> treat infertility
- generates pluripotent stem cell lines from patients with inherited diseases -> understand why disease develop & use in personalised drug discovery efforts
- no need to use immunosuppressant drugs after transplant & overcome problem of looking for a suitable donor for transplantation
- derived from patient’s own cells -> will not be rejected by immune system
- adult tissue used to make iPSC can be easily obtained from donor without risk to donor
possible problems of iPSC [3]
- low efficiency -> conversion from adult somatic cells to iPSCs is incredibly low
- genetic modification of adult somatic cells to obtain iPSCS may cause cancer by over expression of POG or switching off of TSG
- ethical concerns related to creation of embryos & children from iPSC-derived sex cells
what are ethical complications?
- means of obtaining SC (techniques involving destruction of human embryos)
- human cloning
- exploitation of embryo & egg donors
compare human embryonic SC & human adult SC [DRSAD]
[dy/dx ability]
[role in body]
1. ESC: develop embryo into an entire human
2. ASC: replace specific cells in body which die throughout life due to wear & tear, disease or illnesses
[sources]
1. ESC: unused IVF embryos that have been donated or embryos created for the purpose from donated eggs and sperms
2. ASC: bone marrow, muscles & skins, and from foetus, umbilical cord & placenta
[advantages in research & therapy development]
1. ESC: treat wide range of disease -> pluripotency allows SC to produce any cell type, strong ability to self-renew -> constant supply of ES cells, make up a significant proportion of developing embryo & easier to isolate and grow
2. ASC: less ethical considerations than ESC, avoid problem of immune rejection -> taken from patients’ own body -> cells are genetically identical
[disadvantages…]
1. ESC: genetically different to cells of potential patient -> immune rejection, ethical issues over embryo destruction
2. ASC: limited no. of diff. cell types, conditions support self-renewal have only been identified for a few tissue SC types (skin, cornea), found in small numbers & difficult to isolate, ASC w/ genetic mutation from patients’ own body will not be effective in treatment of genetic disorder
Describe the characteristics to identify all S.C
- Unspecialised cell types that do not have a specific structure or function
- Able to self-renew via mitosis
- Able to differentiate into specialised cell types
Describe the characteristics to identify all S.C
- Unspecialised cell types that do not have a specific structure or function
- Able to self-renew via mitosis
- Able to differentiate into specialised cell types
