Embryonic stem Cells

Embryonic stem cells are cells found inside an embryo at an early stage of development, generally the blastocyst stage, which occurs around five days after fertilisation. These cells are considered pluripotent, which means that they have the ability to differentiate into any cell type in the human body.

Embryonic stem cells are an important subject of research in the field of regenerative medicine and biomedical research. Their potential to differentiate into different cell types makes them attractive candidates for the development of therapies to replace or repair damaged or diseased tissues. For example, they could be used to treat degenerative diseases such as Parkinson's, spinal cord injury or heart disease.

However, the use of embryonic stem cells also raises ethical and political controversies, as obtaining them requires the destruction of the embryo. Because of these concerns, many countries have adopted specific regulations concerning embryonic stem cell research and their use for therapeutic purposes.

To circumvent these ethical problems, researchers have also developed induced pluripotent stem cells (iPS cells), which are obtained by reprogramming differentiated adult cells to a state similar to that of embryonic stem cells. iPS cells offer great potential for research and therapy, while avoiding the controversies associated with the use of embryonic stem cells.

Embryonic stem cells (ESCs) are characterised by the expression of certain specific biomarkers that distinguish them from other cell types. Here are some examples of biomarkers commonly used to identify and characterise embryonic stem cells:
1. SSEA-4 (Stage-Specific Embryonic Antigen-4): SSEA-4 is a cell surface marker frequently used to identify embryonic stem cells. It is expressed on the surface of ESCs, but not in differentiated cells.
2.TRA-1-60 and TRA-1-81: These are glycoprotein antigens expressed on the surface of embryonic stem cells and are also used as markers for their identification.
3. OCT4 (Octamer-binding transcription factor 4): OCT4 is a transcription factor essential for the maintenance of pluripotency in embryonic stem cells. Its expression is often used as an indicator of pluripotency.
4. SOX2: This transcription factor works in collaboration with OCT4 to maintain the pluripotency of ESCs and is also used as a marker for these cells.
5. NANOG: NANOG is another transcription factor important for pluripotency and is also used as a marker to identify ESCs.
6. Rex1 (ZFP42): Rex1 is a gene expressed specifically in embryonic stem cells and is used as a marker for their presence.
7. Alkaline Phosphatase (ALP) : The activity of the enzyme alkaline phosphatase is often associated with embryonic stem cells and is used as an indicator.
8. KLF4 (Kruppel-like factor 4): This transcription factor is involved in the maintenance of pluripotency in ESCs and is sometimes used as a marker.
9. NODAL: Nodal is a signalling protein involved in embryonic development and is often expressed in embryonic stem cells.
These biomarkers are used individually or in combination to characterise embryonic stem cells and ensure their pluripotency. Their expression can be assessed using techniques such as flow cytometry, immunohistochemistry, gene expression and other cellular and molecular analysis methods.