Stem Cells Research

Mesochymal stem cells are the multi potent stem cells that can be differentiated into variety of cell types. The cell types into which the MSC has been differentiated are as follows: osteoblast, chondrocytes, myocytes, adipocytes, and as described lately as beta pancreatic islets cells. However in the vivo results are now thought of as the misinterpretation of the spontaneous cell fusion between the damaged neuron a mesochymal cell present in the brain.

While the terms Mesenchymal Stem Cell and Marrow Stromal Cell have been used interchangeably, neither term is sufficiently descriptive as discussed below:

1. Mesenchyme is embryonic connective tissue that is derived from the mesoderm and that differentiates into hematopoietic and connective tissue, whereas MSCs do not differentiate into hematopoietic cells.
2. Stromal cells are connective tissue cells that form the supportive structure in which the functional cells of the tissue reside. While this is an accurate description for one function of MSCs, the term fails to convey the relatively recently-discovered roles of MSCs in repair of tissue.
3. Because the cells, called MSCs by many labs today, can encompass multi potent cells derived from other non-marrow tissues, such as adult muscle or the dental pulp of deciduous baby teeth, yet do not have the capacity to reconstitute an entire organ, the term Multi potent Stromal Cell has been proposed as a better replacement.

History
The scientists first described the clonal nature of the marrow cells in the year 1960. Subsequent experimentation revealed the
plasticity of marrow cells and how their fate could be determined by environmental cues. Culturing marrow cells in the presence of the osteogenic stimuli such as ascorbic acid, inorganic phosphate, dexamethasone can promote the differentiation into osteoblast.

Characteristic
There are many characteristic of the mesenchymal cells. Some of them are as follows:

1. Morphology
Mesenchymal cells are really characterized morphologically by a small cell body with a few cell processes that are long and
thin. As far as the cell structure is concerned I must say that the cell contains large round nucleus with which is surrounded by the chromatin particles giving it a clear appearance. The remaining part of the cell contains the mitochondria, Golgi body, rough endoplastic reticulam. The cells are long and thin and are widely dispersed.

2. Detection
There is no test available for finding the MSC on a single cell. The MSC really cannot be detected up till now.

However I really feel that the mesenchymal cells are quiet important for the human body and if you will not have it in the right quantity then I must tell
you that you will definitely find yourself really caught by some disease or the other sooner or later.

Dendritic cells (DCs) are a kind of the immune cells and as such it forms the part of the mammalian immune system. As far as the main process is concerned I must say that its main job is to process the antigen material and current it on the surface to other cells of the immune system, thus functioning as antigen-presenting cells.

The dendretic cells are present in the small quantities in the tissues that are in contact with the external environment which is mainly the skin and the inner lining of the stomach, lungs, nose and the intestine. We can also find them in the immature state of the blood.

As soon as they are activated they move to the lymphoid tissues where they react with the T cell and the B cells to initiate and shape the adaptive immune response. At definite expansion stages they grow branched projections, the dendrites that give the cell its name. However, these do not have any particular relation with neurons, which also have similar appendages. Undeveloped dendritic cells are also called veiled cells, in which case they possess large cytoplasmic ‘veils’ rather than dendrites.

History
Dendritic cells were first described by Paul Langerhans (Langerhans cells) in the late nineteenth century. It wasn’t until 1973, on the other hand, that the term “dendritic cells” was given by Ralph M. Steinman and Zanvil A. Cohn. In 2007 Steinman has been awarded the Albert Lasker Award for Basic Medical Research for his discovery.

Types of Dendritic cells
There are generally two kinds of the dendritic cells. I must say that the two kind of the dendritic cells are myeloid and plasmacytoid which is also called the lymphoid.

I would at first like to discuss the myeloid dendritic cells.

1. Myeloid dendritic cells
These are most similar to the monocytes. The MDC are made up of two subsets:

• The more common mDC-1, which is a major stimulator of T cells.
• The extremely rare mDC-2, which may have a function in fighting wound infection.

2. Plasmacytoid dendritic cells
These look like the plasma cells but have the certain characteristic of the myeloid dendritic cells.

• Characteristic of the immature dendritic cells
• High intracellular MHC II in the form of MIICs.
• Expression of CD1a.
• Active endocytosis for certain particulates and proteins; presence of FcgR and active phagocytosis.
• Deficient T cell sensitization in vitro.
• Low/absent adhesive and costimulatory molecules (CD40/54/58/80/86).
• Low/absent CD25, CD83, p55, DEC-205, 2A1antigen.
• Responsive to GM-CSF, but not M-CSF and G-CSF.
• Maturation inhibited by IL-10.

Similarly there are some characteristic of the mature dendritic cells and I must tell you that these cells are really of great importance.