Flashcards in Stem Cells and Regenerative Medicine Deck (21):
Define 'stem cells'
These are primitive, undifferentiated cells which can divide indefinitely and are self-renewing, giving rising to progeny that then differentiate into specialised cells.
What are pluripotent stem cells?
Can differentiate into cells derived from any of the three germ layers
What are multipotent stem cells?
can give rise to several specialised cells or tissues of an organism (often tissue-specific) e.g. Haemopoeitic stem cells
What are oligopotent stem cells?
Can generate a few cell types within a particular tissue
What are unipotent stem cells?
Can produce only one cell type, but still capable of self-renewing
What are adult stem cells?
Rare, undifferentiated cells found among differentiated cells in a tissue or organ. They are capable of differentiating to produce the major specialised cell types of the tissue; adult stem cells are multipotent.
What is the primary role of adult stem cells?
To maintain and repair the tissue in which they are found.
How could you identify an embryonic stem cell in a culture?
Grow indefinitely in culture in the primitive embryonic state, maintain normal karyotype and expression of telomerase (immortal cell division). presence of markers that are only found in undifferentiated cells, able to differentiate into a wide range of cell types in vitro and in vivo
What are the 3 germ cell layers?
Endoderm, mesoderm and ectoderm
What is endoderm?
The internal layer of germ cells which gives rise to pancreas, liver, thyroid, lung, bladder and urethra
What is mesoderm?
The middle layer of germ cells which gives rise to bone marrow, skeletal/smooth/cardiac muscle, heart, blood vessels and kidney tubules
What is ectoderm?
The external layer of germ cells which gives rise to skin, neurones, eyes, ears and pituitary gland
What are stem cell niches?
Stem cells though to be maintained and perhaps defined by the environment produced by surrounding differentiated cells; differentiated cells may secrete specific factors into surrounding matrix or communicate with stem cells via gap junctions - can induce a stem cell to die, divide or differentiate
Describe symmetric stem cell division
2 stem cells or two differentiated cells produced
Describe asymmetric stem cell division
Stem cell and differentiated cell produced
Why is therapeutic cloning beneficial?
Ideal tissue for regenerative medicine because it is genetically identical to patient (circumvents problem of tissue rejection), use to study diseases
What are the challenges of therapeutic cloning?
Percentage of successful clones is low, creating potential embryo (not fertilised) for research or treatment, practical source of oocytes, slippery slope to reproductive cloning
What are some of the challenges with the use of embryonic stem cells for transplantation therapies?
Purity and production problems, cancer problems (embryonic stem cells may give rise to disorganised growths known as teratomas), immunology problems, have to be able to match the graft to the donor, ethical issues
What are the advantages of using adult stem cells over embryonic cells
No legal/ethical concerns, using own cells circumvents issues with immunological rejection, shown no lead to tumour formation
What are the advantages of using iPS cells
No need for embryos, and circumvents immunological rejection