Stem Cells

A stem cell is a divisive cell that can divide to produce other reproductive cells that continue to function as stem cells and other cells intended for differentiation. Stem cells are a continuous source of various cells that make up the tissues and organs of animals and plants. There is a great deal of interest in stem cells because they are powerful for developing therapeutic approaches to replacing damaged or damaged cells due to various disorders and injuries.

Stem cells are the totipotent progenitor cells that can regenerate and differentiate between multiple lines. The human body is composed of many cells and tissues but these stem cells are the origin of all tissues and organs. The stem cell can be easily identified from other cells in the body in terms of their ability to regenerate. It can be divided into the same cells.

The stem cells help in repairing and replacing functions of the tissues in the body and these also have a great healing property. This is the most important function of stem cells.

Types of stem cells:

There are two types of stem cells. These are also known as tissue stem cells. They are:

a. Embryonic stem cells:

Embryonic stem cells are stem cells derived from the weight of the inner cell of the mammary at the very beginning of development, forming a blank sphere of dividing cells. Embryonic stem cells from human embryos and embryos of other mammals can be implanted in tissue culture.

1. Human embryonic stem cells:

Human embryonic stem cells form different types of in-vitro tissue and form teratomas when attached to weakened mice. It is not known whether the cells can bind all the tissues of the human embryo, but it is thought that in some of their structures, they are truly pluripotent cells. So they are considered a potential source of various cellular treatments — mutations of a type of disabled patient cells with healthy cells. Many cells, such as dopamine-secreting neurons in the treatment of Parkinson’s disease and pancreatic beta cells that produce insulin to treat diabetes, can be produced by embryonic stem cells. Cells for this purpose were previously only available to highly limited sources, such as pancreatic beta cells found in cadaver donors of human organs.

1. Mice embryonic stem cells:

Mice embryonic stem cells are the most studied mouse embryonic stem cells, first developed in 1981. This type of stem cell can be permanently enlarged in the presence of leukaemia inhibitory factor (LIF), glycoprotein cytokine. When embryonic stem cells are injected into a premature mouse embryo in the blastocyst phase, they will be embedded in the embryo and produce different cells that make up the majority or all of the lateral tissue. This ability to reproduce mouse embryos is a key defining characteristic of embryonic stem cells, and as a result, they are considered pluripotent — that is, able to supply any type of adult cell. When embryonic stem cells are stored in a culture where LIF is absent, they will divide into “embryoid bodies”, which resemble the original mouse embryos in the egg-cylinder phase, and embryonic stem cells inside the outer layer of the endoderm. When embryonic stem cells are attached to an adult mouse, they will grow into a type of tumour called a teratoma, which contains a variety of different types of tissue.

b. Adult stem cells:

Other tissues of the adult body, such as the skin epidermis, the small intestine lining, and the bone marrow constantly change cells. They contain permanent stem cells as well as a very large number of “growth-promoting cells” that come from the stem cells and divide the number of times until they are different. The stem cells in niches are made up of other cells, producing substances that keep the stem cells alive and working. Other types of tissue, such as liver tissue, show little cell division or divide cells only when they are injured. In these tissues, there is almost no special stem-cell count, and any cell can contribute to tissue regeneration when needed.

1. Epithelial stem cells:

Keratinocytes are the cells present in the epidermis of the skin. Only the basal layer, near the dermis, contains dividing cells. Most of these cells are stem cells, but most of them grow in cells. Keratinocytes slowly emerge from the epidermis as they grow, and eventually die and are removed from the skin surface. The epithelium forms a small intestine called villi, which are connected by small holes called crypts. Separating cells are found in crypts, with stem cells lying near the base of each crypt. Cells are continuously produced in crypts, migrated to villi, and eventually released into the intestinal lumen.

Ii. Hematopoietic stem cells:

The bone marrow contains hematopoietic stem cells. These produce all types of antibodies and blood cells. Large numbers of hematopoietic stem cells are found in the umbilical cord and small numbers are found in peripheral blood. In the bone marrow, hematopoietic stem cells focus on osteoblasts of trabecular bone and blood vessels. They produce lymphocytes, granulocytes, RBCs, and other types of cells that depend on the size of the growth factor in the surrounding area. 

Applications:

1. Replace damaged tissues and organs
2. To grow new cells
3. Change the parts in the human body that don’t work
4. Testing of drugs for efficiency
5. To test cancerous cells
6. Treatment of cardiovascular diseases and brain diseases

Conclusion:

Stem cell technology continues to emerge as a result of a multidisciplinary effort, with clinical use of modified stem cells that include the development of transplantation and gene therapy. The practice of cloning and nuclear transfer to stem cells is linked to several other behaviour problems. Improved understanding of the interactions between cytokines and the extracellular matrix will be required for successful ex-vivo manipulation of stem cells. Cytokines may lower the binding capacity of stem cells and portions of the stromal microenvironment, allowing stem cells to be transferred to the peripheral bloodstream more easily.