Do you know that a doctor can use stem cells for a number of reasons?
Cells in the human body have specific purposes, however, these are cells that do not yet have a specific role and can become almost any cell that is required.
Stem cells are undifferentiated cells that tend to turn into certain cells as the body needs them, type of health us department of health and human services .
Scientists and doctors are interested in these cells as they help to explain how some functions of the bodywork and how in some cases they go wrong.
Moreover, stem cells also show promising results for treating certain diseases that currently do not have a cure.
Keep on reading.
Stem Cells
Stem cells are the raw material in the body, while other cells tend to have specialized functions.
Under the right conditions in the body or laboratory, these divide to form more cells: daughter cells.
These daughter cells either become new stem cells or specialized cells, i.e. differentiation with a more specific function like blood cells, brain cells, heart muscle cells, or bone cells.
However, no other cells in the body have the natural ability to generate new cell types.
Sources
Stem cells originate from two main sources:
- adult body tissues
- embryos
Scientists also working on ways to develop these cells from other cells, using genetic “reprogramming” techniques.
Let’s discuss these as follows:
Adult Stem Cells
The body of a person contains stem cells throughout their life and the body can use them whenever it needs them.
Also known as tissue-specific or somatic stem cells, adult stem cells tend to exist throughout the body from the time an embryo develops.
Moreover, the cells are in a non-specific state, however, are more specialized than embryonic stem cells.
They will remain in this state until the body needs them for a specific purpose, like skin or muscle cells.
Day-to-day living means that the body is constantly renewing its tissues.
In some parts of the body, like the gut and bone marrow, these cells regularly divide to produce new body tissues for maintainance and repair.
Furthermore, stem cells are present inside different types of tissues in the body, and scientists have found them in tissues including:
However, it is important to note that these cells are difficult to find. They can stay non-dividing and non-specific for years until the body needs them to repair or grow new tissues.
Adult stem cells can divide or self-renew indefinitely, which means that they can generate a number of types from the originating organ or even regenerate the original organ entirely.
This division and regeneration are how skin wounds heal or how an organ like a liver can repair itself after damage.
In past, however, scientists were of the view that adult cells can only differentiate based on their tissues of origin.
But some evidence now suggests that they can differentiate to become other cell types also.
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Embryonic Stem Cells
From the earliest stage of pregnancy, after the sperm fertilizes the egg, an embryo forms.
Around 3 to 5 days after a sperm fertilizes an egg, the embryo will take the form of a blastocyst or call of cells.
The blastocyst tends to contain these cells and will later implant in the womb, while embryonic stem cells come from a blastocyst that is 4 to 5 days old.
When scientists take these cells from the embryo, these are often extra embryos that result from in vitro fertilization, IVF.
Moreover, in IVF clinics, the doctor often fertilizes a number of eggs in a test tube, to make sure that at least one survives.
They will then implant a limited number of eggs to begin a pregnancy.
When a sperm fertilizes an egg, these cells will combine to form a single cell: a Zygote.
This single-celled zygote will tend to begin to divide, forming 2,4,8,16 cells and so on, which is now an embryo.
Soon and before the embryo implants in the uterus, this mass of around 150 to 200 cells is the blastocyst and it consists of two parts:
- an outer cell mass that becomes part of the placenta
- an inner cell mass that will develop into the human body
Furthermore, the inner cells are where embryonic stem cells are. Scientists call these Totipotent cells.
The term totipotent refers to the fact they have total potential to develop into any cell.
With the right stimulation, these cells can become blood cells, skin cells, and all other cell types that the body needs.
In early pregnancy, the blastocyst stage continues for about 5 days before the embryo implants in the uterus or womb.
At this stage, these cells often begin to differentiate.
Embryonic stem cells can differentiate into more cell types than adult cells.
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MSCs, and iPS
Mesenchymal stem cells, MSCs come from the connective tissue or stroma that surrounds the organs and other tissues of the body.
Moreover, scientists use MSCs to create new body tissues like bone, cartilage, and fat cells.
They may one day play a role in solving a wide range of health problems.
On the other hand, induced pluripotent stem cells, iPS are created in the lab, using cells and other tissue-specific cells.
These cells behave in the same way as embryonic cells, so they can be useful for developing a range of therapies.
However, more research and development are important.
To grow these cells, scientists first extract samples from adult tissues or an embryo.
Then they place these cells in controlled culture where they can divide and reproduce but not specialize further.
Moreover, stem cells that are dividing and reproducing in a controlled culture are stem-cell lines.
Researchers manage and share stem-cell lines for different purposes.
They can help stimulate these cells to specialize in a particular way. This process is directed at differentiation.
Until now, it has been easier to grow a large number of embryonic stem cells than adult cells.
However, scientists are making progress with both cell types.
Types of Stem Cells
Researchers categorize these cells according to their potential to differentiate from other types of stem cells.
Embryonic stem cells are the most potent, as their job is to become every type of cell in the body.
The full classification includes:
Totipotent: These stem cells can differentiate into all possible cell types, the first few cells that appear as the zygote starts to divide are totipotent.
Pluripotent: These can turn into almost any cells, and cells from the early embryo are pluripotent.
Multipotent: These cells can differentiate into a closely related family of cells.
Moreover, adult hematopoietic stem cells, for instance, can become red and white blood cells or platelets.
Oligopotent: These can differentiate into a few different cell types, while adult lymphoid or myeloid stem cells can do this.
Unipotent: These can only produce cells of one kind, which is their type.
However, they still can renew themselves and examples are adult muscle stem cells.
Furthermore, embryonic stem cells are considered pluripotent instead of totipotent as they cannot become part of the extra-embryonic membranes or the placenta.
Uses
It is important to note that these cells do not themselves serve any single purpose but are important for a number of reasons.
First, with the right stimulation, many stem cells can take on the role of any type of cell and can regenerate damaged tissue, under the right conditions.
This potential use can help save lives or repair wounds and tissue damage in people after an illness or injury.
Scientists see a number of possible uses for these cells. These are:
Tissue Regeneration
Tissue regeneration is the most important use of stem cells. Until now, the person who needs the kidney, for instance, will need to wait for a donor and undergo a transplant.
There is a shortage of donor organs, however, by instructing these cells to differentiate in a certain way, scientists can use them to grow a specific tissue type or organ.
Cardiovascular Disease Treatment
In 2013, according to the report of a team of researchers from Massachusetts General Hospital in PNAS Early Edition, they created blood vessels in laboratory mice, using human stem cells.
Within 2 weeks of implanting these cells, networks of blood-perfused vessels had formed.
The quality of these new blood vessels is as good as the nearby natural ones.
The authors hope that this type of technique can eventually help to treat people with cardiovascular and vascular diseases.
Brain DiseasOneTthe great doctors day, doctors may be able to use replacement cells and tissues to treat brain diseases like Parkinson’s and Alzheimer’s.
For instance, in Parkinson’s damage to the brain cells leads to uncontrolled muscle movements.
Scientists can use these cells to replenish the damaged brain tissue that can bring back specialized brain cells that can help stop uncontrolled muscle movements.
Researchers are already trying to differentiate embryonic cells into these types of cells, so treatments are promising.
Other Uses
Some other uses are:
Cell Deficiency Therapy
Scientists hope that one day they may be able to develop healthy heart cells in the lab that they can transplant into people with heart disease.
These new cells can help repair heart damage by repopulating the heart with healthy tissue.
In the same way, people with type 1 diabetes can receive pancreatic cells that can help replace the insulin-producing cells that their immune systems have either lost or destroyed.
Moreover, the only current therapy is a pancreatic transplant, and very few pancreases are available for transplant.
Blood Disease Treatments
Today, doctors use adult hemopoietic cells to treat diseases like leukemia, sickle cell anemia, and other immunodeficiency problems.
Hematopoietic stem cells occur in blood and bone marrow and can also produce all blood cell types.
Moreover, these include red blood cells that carry oxygen and white blood cells that fight diseases.
Donating or Harvesting Stem Cells
People can donate these cells to help a loved one or possibly for their use.
The donation can come from the following sources:
Bone Marrow: The doctor can take these cells under general anesthesia, often from the hip or pelvic bone.
Technicians can then isolate the stem cells from the bone marrow for storage or donation.
Peripheral Stem Cells: A person can receive a number of injections that cause their bone marrow to release stem cells into the blood.
Then, the doctor will remove the blood from the body, using a machine that separates the stem cells and then returns the blood to the body.
Umbilical Cord Blood: Stem cells can also be harvested from the umbilical cord after delivery with no harm to the baby.
Some people donate the cord while others store it.
This harvesting of stem cells can be expensive, however, the advantages for future needs are:
- the stem cells are easily accessible
- fewer chances of transplanted tissue being rejected if it comes from the own body of the recipient
Research and Scientific Discovery
Stem cells are not only useful as potential therapies, and regenerative medicine, but also for research and clinical trials.
For instance, scientists have found that switching a particular gene on or off can cause it to differentiate.
Knowing this is helping them to investigate which genes and mutations can cause which effect.
Armed with this knowledge, they may be able to find what causes a wide range of illnesses and conditions, some of which do not have a cure yet.
Moreover, abnormal cell division and differentiation are also responsible for conditions that include cancer and congenital disabilities that stem from birth.
Knowing what causes the cells to divide in the wrong way can help to lead to a cure.
Stem cells can also help in the development of new drugs, according to Bethesda MD National Institutes of Health US Department of Health and Human Services.
Instead, of testing drugs on human volunteers, scientists can assess how a drug affects normal healthy tissues by testing it on tissue that grows from stem cells.
Controversy
It is important to note that there is controversy about stem cell base research, which relates to work on embryonic stem cells:
Use of Embryo
The argument against using embryonic stem cells is that it destroys a human blastocyst and the fertilized egg cannot develop into a person.
Nowadays, researchers are looking for ways to create or use these cells that do not involve embryos.
Mixing Humans and Animals
Stem cell research often involves inserting human cells into animals like mice or rats.
Moreover, some people argue that this can create an organism that is part human.
In some countries, it is illegal to produce embryonic stem cell lines.
In the United States, scientists can create or work with embryonic stem cell lines, however, it is illegal to use federal funds to research these lines that were created after August 2001.
Stem Cell Therapy and FDA Regulation
Some people are offering “stem-cell therapies” for a range of purposes like anti-aging treatment.
However, most of these do have approval from the U.S Food and Drug Administration.
Some of them may be illegal, and some can be dangerous.
Anyone who is considering them should check with the provider or with the FDA whether the product has approval.
And that if it was made in a way that meets FDA standards for safety and effectiveness.
