Regenerating Organs Using Stem Cells
Did You Know?
Stem cells can be derived from both embryos and adults.
Learn About a Stem Cell
What Is a Stem Cell?
Stem cells are unspecialized cells, meaning they have the potential to stay a stem cell, or become a cell with a specific function. Stem cells serve as an internal repair system, because once a stem cell goes through the process of mitosis, the daughter cells can replace any damaged or dead tissue cells. These cells can " essentially [divide] without limit to replenish other cells as long as the person or animal is still alive" (NIH). Once divided these cells can also become specialized, meaning that if needed these cells could act as a red blood cell or muscle cell. There are three main types of stem cells; embryonic stem cells, somatic 'adult' stem cells, and induced pluripotent stem cells (H5).
Click to watch a Ted Talk about the basics of what a stem cell is, and the potential stem cells have. This video features Neurologist Crystal Ruff, who has been researching bio regenerative medicine for 12 years (H17).
What Are The Characteristics of Stem Cells?
Most cells in the body are specialized, and have a specific function. For example, red blood cells are specialized cells because they have one job, and one job only, to carry oxygen through out the body. However stem cells are not differentiated, so they have the ability to become what ever cell needed. For example, if you cut your finger, the stem cells in your skin and bone marrow, work to replace the dead skin cells and red blood cells. Stem cells can also regenerate cartilage, bone, and even become a nerve cell. Stem cells have unique characteristics and properties, that separate themselves from differentiated cells. One characteristic they have is the ability to renew itself, this is unique since when normal cells die, they can not be renewed. "..[S]tem cells may replicate many times, or proliferate. A starting population of [embryonic] stem cells that proliferates for many months in the laboratory can yield millions of cells. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells are said to be capable of long-term self-renewal" (SCP). Stem Cells are also different from differentiated cells, because "... under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions" (NIH). Stem cells can give rise to other specialized cells that can't reproduce themselves, through the process of differentiation. Therefore, becoming the most valuable type of cell (H4, H5).
What are the Different Types of Stem Cells?
There are three main types of stem cells; Embryonic, Somatic, and Induced Pluripotent.
Click to watch a video about the different types of Stem Cells; embryonic, somatic, and induced pluripotent. This video is explained by Professor Iona Novak, Head of Research, Cerebral Palsy Alliance Research Institute (H18).
Embryonic Stem Cells
Embryonic stem cells (ES cells) are pluripotent, meaning they can potentially become any cell the body needs, or develop into more stem cells. ES cells are the most universal stem cells and versatile, allowing ES cells to regenerate damaged tissue and organs. However, 90% of stem cell research is done on somatic stem cells rather than embryonic stem cells, contrary to many people beliefs (H1, H2, H5, H6).
This illustrates the process ES cells go through in order to become differentiated. Neural, lung, heart, and bone cells are just a few examples of the possibilities a stem cell can transform into (H12).
Where do They Come From?
ES cells are taken from blastocyst, embryos that are 3-5 days old. These ES cells have been taken from embryos who were donated by IVF patients. ES cells can also be derived from umbilical cord blood and the placenta. However umbilical cord blood and placenta stem cells cannot be used on all patients. For instance, if a child was battling cancer, he/she could not use those stem cells for their benefit because the placenta and umbilical cord could already be infected with the child's cancer cells (H3, H5).
This demonstratesthe steps taken in order to grow and harvest ES cells in a lab (H7).
Somatic 'Adult' Stem Cells
Somatic, also known as adult stem cells, exist naturally with in the body. These stem cells replace the dead cells through out your body that you lose daily. For example, if you had a cut, these stem cells would replace any red blood cells you lost. Somatic stem cells are more limited compared to ES cells because somatic stem cells are multipotent, meaning they do not have the ability to transform into any type of cell in the body. "Typically, there is a very small number of stem cells in each tissue and, once removed from the body, their capacity to divide is limited, making generation of large quantities of stem cells difficult" (NIH). Unlike ES cells, somatic cells are limited on the number of times they can divide, resulting in a limited amount of stem cells in the body. However, recent studies show that there is a possibility that adult stem cells may be able to create various types of cells. Currently, scientists are experimenting to prove this theory (H2, H5, H6, H8).
Shows how limited somatic cells are, and when they become differentiated. This also illustrates where the majority of somatic stem cells are inhabited, in the bone marrow (H13).
Where do They Come From?
Somatic stem cells naturally live through out the human body. They are "...found among differentiated cells in a tissue or organ" (NIH). Somatic stem cells live with in matured tissue, and are only activated when need. These cells primarily live in bone marrow, but they can also be extracted from red blood cells (H3,H5).
Illustrates where most somatic cells are inhabitant in the body (H8).
Induced Pluripotent Stem Cells
Induced pluripotent cells (iPS) are cells that were once adult cells, but were turned into stem cells by scientists in a lab. "This new technique may allow researchers to use reprogrammed cells instead of embryonic stem cells and prevent immune system rejection of the new stem cells." (Mayo Clinic). iPS cells can become any type of cell in the body, once they are reprogrammed. iPS cells are able to act just like an embryonic cell, but there is no longer a need for an embryo. However, these cells can become more effective than ES cells since the patient's adult cells are being used in treatment. Therefore, there will be a smaller chance of rejection (H2).
Demonstrates the how the reprogramming factors effect the adult cells, and what type of cells the induced pluripotent can become (all three cell germ layers) (H11).
Where Do They Come From?
iPS cells were created in labs by scientist, and "...are adult cells that have been genetically reprogrammed to act like an embryonic stem cell. These cells are forced to express genes and factors important for maintaining the defining properties of embryonic stem cells" (NIH). iPS cells are made from the patient's fat, skin, bone, and fibroblast (H5).
Shows how iPS cells are created in a lab, and how they can go on to from any type of cell in the body (H8).
Continue Learning
