advantages and disadvantages of iPSC vs embryonic stem cells

Question 1

what are the 6 pros of IPSc?

Answer 1

• cells readily available
• unlimited proliferative ability
• can potentially form any cell type
• modelling human genetic diseases
• few ethical issues
• have some genetic background to patient therefore rejection of transplant is low

Question 2

what are the negatives given in the lecture for iPSCs?

Answer 2

• low reprogramming rate
• potential to form tours
• genetic mutations can occur during long term culture

Question 3

what are the 4 pros of ESCs?

Answer 3

• they are available from IVF clinics
• unlimited proliferative abilities
• pluripotent can potentially form all adult cell types
• can be sed fir toxicity testing and development of new drugs

Question 4

what are the 4 disadvantages if ESCs

Answer 4

• have a different genetic background to donor so there is a risk
• potenital for forming tumours such as teratomas
• genetic mutations may arise during long term culture
• major ethical issues

Question 5

what was found when they looked for chromosomal changes in ESC lines? which chromosomes were most affected?

Answer 5

120 human ES cell lines were analysed for karyotype abnormalities and group according to whether abnormalities were seen at early or late passage. Most (66%) were normal but the study identified a tendency to acquire chromosomal abnormalities with prolonged culture. Chromosomes 1, 12, 17 and 20 were most commonly affected.

Question 6

what region in the genome was found to be particularly changed when human ES lines were observed, why is this?

Answer 6

a minimal amplicon in chromosome 20q11.21, including three genes expressed in human ES cells, ID1, BCL2L1 and HM13, occurred in >20% of the lines. Of these genes, BCL2L1 is a strong candidate for driving culture adaptation of ES cells

Question 7

what is the problem with culture adaption in ES cells, what can this result in?

Answer 7

Culture adaptation of human pluripotent stem cells. During prolonged culture many cells either die or differentiate, leading to selection for cells carrying mutations that permit them to grow (self renewal). Culture adaptation leads to cells with enhanced growth characteristics and sometimes to embryonal carcinoma cells (malignant ES cells) that have lost the ability to differentiate.

Question 8

what are the 3 disadvantages of using adult stem cells?

Answer 8

• veyr rare and often difficult to obtain
• may have limited proliferative ability
• may have limited potency, producing just a few cell types

Question 9

what are the advantages of adult stem cells?

Answer 9

• can be isolated from patient thereby reducing the chance of rejection
• can be used to test patient specific responses to drugs
• modelling human genetic diseases disorders
• few ethical issues

Question 10

give an example of adult stem cells being used for regenerative medicine for a woman

Answer 10

Claudia Castillo suffered severe damage to her left Bronchus as a result of Tuberculosis. A trachea was isolated from a recently deceased donor and stripped of its living cells, leaving a collagenous frame. This was seeded with tracheal cells made from Claudia’s bone marrow stem cells, incubated in a “bioreactor” for 4 days, then used to replace the damaged bronchus. The transplant was successful and not rejected by Claudia’s immune system.

Question 11

why do ESCs have unlimited proliferative capacity?

Answer 11

• they have telomerase

Question 12

what would cause teratoma formation ?

Answer 12

• residual pluripotent and undifferentiated ESCs in transplants

Question 13

what is an important use of ESCs?

Answer 13

• they can be used to look at development and the factors involved differentiation

Question 14

what must be remembered when using ESCs to look at development?

Answer 14

• they have been selected for proliferation and in vitro survival

Question 15

are ESCs from pre or post implantation?

Answer 15

pre

Question 16

why is the ESC good for very early development studies?

Answer 16

t provides access to the popula- tion of early precursor cells that are difficult if not impossible to identify in vivo.

Question 17

what is good about ESCs in terms of mutation analysis?

Answer 17

it could allow the study of targeted mutations of genes that may be lethal in vivo but can be studied in vitro.

Question 18

what is the problem of ESC in terms of cell numbers ?

Answer 18

difficult to get large numbers or repeating tissues

Question 19

what is interesting about the immunoreactivity of ESCs?

Answer 19

In a recent report,95 human ES cells were shown to express low levels of MHC class I proteins. This expression was only moderately increased during in vitro and in vivo differentiation but was significantly augmented after treat- ment of the cells with interferon-􏳊. In contrast, MHC class II antigens and the ligands for NK cell receptors were not expressed on the surface of the ES cells or their derivatives. The absence of MHC class II antigens on human ES cells and their cardiomyocyte derivatives may be important because cells expressing these proteins, such as B cells, macrophages, dendritic cells, and endothelial cells, are believed to be highly immunogenic. T