Research into Embryonic stem cells shows promise

November 12, 2012

Research into Embryonic stem cells shows promise

Embryonic stem cells originate from embryos that have been developed from eggs which have been fertilized in vitro. The eggs are donated with consent from donors for research purposes.

Cell culture is the term used for growing cells in laboratory conditions. hESC (Human Embryonic Stem Cells) are produced by cells being transferred from a pre-implantation embryo into the culture dish which contains a mixture of nutrients. The dish is usually covered with embryonic skin from the skin cells of mice which have been treated. This prevents the cells dividing as the cells of the mice offers a surface which is sticky and the eggs stay attached. This is known as a feeder layer and these cells release nutrients. Researchers have now created an alternative process for growing embryonic stem cells which does not include using mouse feeder cells. The risk associated with the macromolecules and viruses in the mice cells passing to human cells is greatly reduced.

Cells from the pre-implantation stage embryo that are placed in a culture dish do not produce an embryonic cell line every time. If plated cells survive, then divide and multiply to overcrowd the culture dish they will be removed and placed into several culture dishes. This process which is known as sub-culturing or re-plating of the cells is a process which is repeated frequently and can be over a period of months. This sub-culturing of cells is known as a passage. When embryonic stem cells multiply in the cell culture environment over an extended time period without specializing they are known as pluripotent. If no genetic abnormalities have developed this is known as an embryonic stem cell line.

Scientists will test cells at different points during the generation of the hESC lines checking for the essential properties required to make them human embryonic stem cells. Testing which scientists carry out in the laboratory are:

Sub-culturing and growing of cells. This enables the cells to grow long term and have the capability of self renewal.

Specific techniques are carried out to establish that Oct4 and Nanog transcription factors are present as they are associated with the preservation of the stem cells.

Chromosomes are examined to find out if any damage has occurred or if there has been any changes in the cells. But this process will not find any signs of cell mutations.

Establishing if the cells can be sub cultured or re-grown after they have went through the process of being frozen, thawed and re-plated.

Test to establish if the hESC are pluripotent by letting the cells differentiate of their own accord. Because the stem cells are injected into mice with a compromised immune system they will not be rejected and this lets scientists observe the differentiation and growth of human stem cells. This procedure can check if a teratoma (benign tumor) is developing.

Embryonic stem cells that are in culture and are grown in the correct conditions where they can stay unspecialized (undifferentiated). If the cells begin to form together in a group and embryoid bodies begin to form then they will start to differentiate of their own accord. When this occurs, nerve, muscle cell and other types of cells can form. Specialization which has not been planned is a good sign as it means the culture of the cells is high quality.

If scientists can control the direction of the specialized embryonic stem cell into particular cell types certain diseases may be treated. These could include injuries to the spine, Parkinson’s disease, Duchenne’s muscular dystrophy, diabetes, hearing and vision loss and heart disease.

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