What are Stem Cells

What are Stem Cells

What are stem cells and where do they come from is a question many have when they hear about stem cell research. Learn more about stem cells by scrolling down to the article below.
You must have come across many articles as well as news about break through medical treatments with the help of stem cells. Many hospitals and labs come up with awareness programs related to umbilical cord blood stem cell storage as well as stem cell research.

An Overview
Stem cells are naïve cells that have no specialized function and are yet to make up their mind about which cell they would like to develop into. In other words, they are non-specialized cells that can make exact copies of themselves and differentiate into specialized cells according to the stimulus received. They are kind of master cells within the body that divide and form daughter cells that differentiate into specific cells like blood cells, liver cells, brain cells or even muscle cells. These cells are special cells of the body as they are the only cells within the body that have the ability to differentiate into different cells.

They have the ability of self renewal that is go through number of cell division cycles while maintaining their undifferentiated state. They also have the property of 'potency' that is, ability to differentiate into specialized cell type. This property gives rise to different types of cells like totipotent, pluripoten, multipotent, or unipotent.

A stem cell undergoes two processes that helps in maintenance of the number of stem cell number within the body. These two processes or mechanisms that help in maintaining stem cell number are:
  • Obligatory Asymmetric Replication: This mechanism leads to division of stem cell into one daughter cell that is totally identical to the original stem cell and another differentiated daughter cell.
  • Stochastic Differentiation: The stem cell that develops two differentiated daughter cells, one of which undergoes mitosis producing two stem cells that are identical to the original stem cell.
Origin and Source
Different types of stem cells come from different sources as mentioned below:

Embryonic Stem Cells
Embryonic stem cells come into existence during the first 4 to 5 days of embryo development. The 8 cell embryo contains totipotent cells that are undifferentiated and have the ability to develop any cell to make up a human. Then the embryo develops into a blastocyst it contains only 150 cells. These cells are pluripotent that means they have the ability to develop into any type of cell in the body. This is the characteristic that makes embryonic stem cells so sought after by researchers for regeneration and repairing damaged organs and tissue of the body.

Adult Stem Cells
Adult stem cells are found in the developed organs as well as tissues of the body. These have the property to divide and create cells similar to itself. They can even create more differentiated cells just like themselves. These cells are also called somatic stem cells and germline stem cells. The latter produce gametes. In spite of the name, these are also found in children as well as adults.

Pluripotent adult stem cells are very rare and generally found in the umbilical cord blood. Most of the stem cell research benefits are focused on the ability of self renew indefinitely as well as the potential to differentiate into different cell types. Majority of adult stem cells are multipotent in nature and are called mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, etc.

Amniotic Stem Cells
Amniotic stem cells are present in the amniotic fluid and are very active multipotent cells. They can expand without feeders and are not found to be tumorogenic in nature. These cells can differentiate into adipogenic, osteogenic, endothelial, hepatic, neuronal and myogenic cells.

Adult Cells Induced as Embryonic Stem Cell
The adult cells that are not stem cells are induced to exhibit pluripotent properties. These cells are genetically programmed with help of transcription factors and reprogram the cells to act as embryonic stem cells. This technique is still under research and experiments are carried out to use it for helping human patients.

How do Stem Cells Work
They have the ability of undergoing self renew and differentiate into different cell types. A stem cell divides and has the potential to become a specific cell or remain a stem cell. The stem cell receives a signal to differentiate and get converted into a specific cell. When the signal is received the cell may turn on certain genes that are required to make proteins. These proteins are very important as they are going to decide the cell type the stem cell is to be converted. When the process of differentiation is completed, the cell must have simultaneously stopped dividing. This process of differentiation helps the stem cells become specialized with specific functions.

What do They do
The stem cells divide and regenerate to form different cells. There potential can be tapped and used for treatment of various conditions and diseases like diabetes, heart diseases, Parkinson's disease, Alzheimer's disease, etc. It can also help in repairing severed spinal cords in paraplegics. They can also be used to regenerate certain cells and tissues of the skin, digestive system red blood cells and white blood cells. There are unlimited things that are possible by tapping their potency.

What is Stem Cell Research
Stem cell research is a new technology that focuses on the primitive cells of the human body and converting them into different cells of the body. The stem cell research tries to use the building blocks of human cells for regeneration as well as repair of damaged organs and tissues. Stem cell research also includes cure for a whole range of heart disease, diabetes, Parkinson's disease, etc.

Why are Stem Cells Important
These reasons include the ability of the unspecialized stem cells of self renewal, differentiation and conversion into specialized cells. These characteristics will help in curing many diseases as well give a cure to certain birth defects. They may even help in cell therapy of damaged or dead tissues and have a role in organ transplantation. The regenerative properties can help decrease the need for organ and tissue transplants.

Stem cell research is an extensive field with infinite possibilities. These possibilities bring up the issue of ethics of stem cell research and stem cell research pros and cons. There are many laws around the world that govern the use of stem cell and their research.