What does it mean for stem cells to remain unspecialized or become specialized?

Question

I read and article about stem cells and there's this section that I don't really understand.

"Therefore, in order to develop such treatments scientists are intensively studying the fundamental properties of stem cells, which include:

1. determining precisely how stem cells remain unspecialized and self renewing for many years; and
2. identifying the signals that cause stem cells to become specialized cells. "

So what unspecialized and specialized cells mean? And if you can, can you also explain briefly what stem cells are and capable of?
Thank you. :]

Answer 1

Stem cells are cells that could become any other kind of cell that is needed. When an egg is fertilized and undergoes the first divisions, those cells are not muscle cell or nerve cells or any other special-purpose types of cells. These early cells will form all the body's tissues while the embryo and then the fetus is developing. The cells that make all the other kinds of cells are called stem cells. Before the stem cells develop into the different kinds of cells, the stem cells are referred to as being "unspecialized" or "undifferentiated".

The fundamental properties of stem cells mentioned in your question are:
1. finding out how stem cells can stay stem cells and make more stem cells over the years (instead of changing into specialized cells for the body). Even adults still contain some stem cells. For instance, researchers in Portugal are doing experimental stem cell treatment on victims of spinal cord injury using the patient's own stem cells from their nasal membranes.

2. identifying signals that trigger stem cells to go ahead and change into specialized cells after they have stayed unspecialized for however long. So researchers want to know why stem cells can be stem cells, then at some point the stem cells change. What sets off the change?

All very interesting, of course. I'm hoping that stem cell treatment will help my 22-year-old son who has been quadriplegic for the last 30 months following an accidental spinal cord injury.

Answer 2

When the unspecialized cell reproduces to form another unspecialized cell, the new cells are identical to the mother cell and there are no ageing, but after an unknown signal tells the cells to become specialised, the cell stars to ageing after each division. After 30 mitosis (divisions) the specialised cell will die.. If the signal don't occurs, the cell would reproduce forever.

The stem (unspecialised ) cell can be used to produce specialised cells to form the different body organs.

Answer 3

Unspecialized Stem cells are basically blank body cells, They have the potential to become any cell from skin cells to bone cells. They are the building blocks of the body.

Specialised Stem cells are similar but have been told what they are going to be.

The reason research is being carried out on them so much is because they could be used to rebuild your body such as replace cancerous cells.

Answer 4

They are the healers of the system, which can differentiate (change) into various tissues at chemical will and produce complex tissues from scratch. Stem cells are located throughout the body, the part of the body that has the most stem cells is the nose (cartilage). In a fertilized egg, the stem cells are what make the brain, bones, heart, eyes etc.

"Stem cells are unspecialized. One of the fundamental properties of a stem cell is that it does not have any tissue-specific structures that allow it to perform specialized functions. A stem cell cannot work with its neighbors to pump blood through the body (like a heart muscle cell); it cannot carry molecules of oxygen through the bloodstream (like a red blood cell); and it cannot fire electrochemical signals to other cells that allow the body to move or speak (like a nerve cell). However, unspecialized stem cells can give rise to specialized cells, including heart muscle cells, blood cells, or nerve cells."

"The specific factors and conditions that allow stem cells to remain unspecialized are of great interest to scientists. It has taken scientists many years of trial and error to learn to grow stem cells in the laboratory without them spontaneously differentiating into specific cell types. For example, it took 20 years to learn how to grow human embryonic stem cells in the laboratory following the development of conditions for growing mouse stem cells. Therefore, an important area of research is understanding the signals in a mature organism that cause a stem cell population to proliferate and remain unspecialized until the cells are needed for repair of a specific tissue. Such information is critical for scientists to be able to grow large numbers of unspecialized stem cells in the laboratory for further experimentation."

"Stem cells can give rise to specialized cells. When unspecialized stem cells give rise to specialized cells, the process is called differentiation. Scientists are just beginning to understand the signals inside and outside cells that trigger stem cell differentiation. The internal signals are controlled by a cell's genes, which are interspersed across long strands of DNA, and carry coded instructions for all the structures and functions of a cell. The external signals for cell differentiation include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment."

Answer 5

Your body is composed of billions of cells which all have different functions. E.g. brain cells are different in structure from bone cells because they have a different job to do. This is what is known as being specialised. Stem cells are basically cells which have not yet become specialised and are capable of becoming specialised in order to carry out whatever functions the body is need of.

Answer 6

Basically, stem cells are cells which have the potential to become any of the many different types of cells found in the body, for example muscle cells or liver cells, which do different jobs.
Therefore, stem cells are referred to as 'unspecialised' because they are not 'tied down' to one fate. However, once they have undergone the process of developing into a specific type of cell, they no longer have the ability to change back into such a flexible state; hence, once they have developed into e.g. a liver cell, they are referred to as 'specialised' because they are now specialised to perform the specific function of that cell, and cannot e.g. turn from a liver cell into a nerve cell.
Stem cells are the subject of such intense research at present because their ability to be cultured as unspecialised cells in theory means we could grow them in the lab and then make specific cells 'on demand', for example we could make new nerve cells from them and transplant them into patients to regrow damaged nerve tissue. However, this is not possible at present because
a) we do not yet understand how to make stem cells grow into the tissues that we want because we do not know yet what induces the change into specialised cells
b) the limited capacity of adult-derived stem cells to divide and retain their flexibility regarding their fate makes any possible therapeutic use awkward and difficult, while embryonic stem cells, which divide and retain their lack of specialisation indefinitely, require the destruction of the embryo in order to be obtained, which is the subject of ongoing fierce moral debate

Answer 7

There are various different classifications of stem cells based on “the extent to which they differentiate into different cell types.” (Frequently Asked Questions, n.d.) These include totipotent stem cells, pluripotent stem cells, multipotent stem cells, and unipotent stem cells.

Totipotent stem cells are capable of differentiating into any cell type in the body. “A fertilized egg is a type of totipotent stem cell.” These cells can also be produced within the early stages of embryonic division. (Frequently Asked Questions, n.d.)

Pluripotent cells develop around the four day mark. Like totipotent cells they can differentiate into anything. There are however two exceptions to this: they cannot develop into totipotent cells, nor can they develop into cells of the placenta. (Frequently Asked Questions, n.d.)

Multipotent stem cells develop from pluripotent stem cells. They are responsible for specialized cells in specific tissues. For instance, hematopoietic stem cells, found chiefly in the bone marrow, give rise to all the cells of the blood. Neural stem cells are another example of multipotent stem cells. (Frequently Asked Questions, n.d.)

Unipotenet stem cells as the name suggests, are only capable of producing one cell type. Unipotent stem cells are also known as progenitor cells. A white blood cell would be a type of unipotent stem cell, being derived from multipotent stem cells. Once a unipotent stem cell is formed it is ‘terminally differentiated’, that is, it can no longer develop into any other cell type. (Frequently Asked Questions, n.d.)

Answer 8

I guess that the amount of cells produced is so huge that they dont have enough time to mature. and immature cells can not be specialized