Father of all Cells (STEM CELL):

What is a Stem cell?

A stem cell is a cell with no specific function in the body but has a unique ability to develop itself into any type of specialized cell.

A stem cell may be used to replace damaged cells and tissue that have been damaged or lost due to certain types of diseases.

Our body is an organized collection of specialized cells.

Every cell in our body has a unique function, such as the function of red blood cell is to carry oxygen around our bodies in the blood, but RBC (red blood cell) are unable to divide.

They serve by providing new cells for the body as we grow, and replaces the damaged or lost specialized cells.

They can provide new cells to the body or replace the damaged cells to the two unique ability or property, they are:
1. Stem cells can divide themselves to produce more new cells of the same nature.
2. As they divide, they can change themselves into other types of specialized cell that makes up the body.

Types of Stem Cell:

There are three major types of Stem Cell:
1. Embryonic stem cells
2. Adult stem cells
3. Induced pluripotent stem cells

Embryonic stem cells:

As the name suggests its self, embryonic stem cells are the stem cells found in the Embryo.
Its major function in the embryo is to supply new cells for an embryo as it grows and develops into a baby.
Embryonic stem cells are also said to be pluripotent, which indicates they can change into any type of specialized cell in the body.

Adult stem cells:

As the name suggests itself, adult stem cells ate the stem cells found in the adult’s body.
Adult stem cells serve by providing new cells as an organism grows and to replace the damaged cells.
Adult stem cells are also said to be multipotent, which means they can only change into some specialized cells in the body, not any specialized cells, for example:
1. Various types of cells in the blood are formed from Blood or ( Haematopoietic) stem cells.
2. Skin cells and cells in the hair are created from Skin or ( Epithelial) stem cells.
3. Bone or heart muscle cells are created from Bone marrow stem cells.

Induced pluripotent stem cells:

Induced pluripotent stem cells or ( iPS cells ), these are the stem cells that are made by scientists in the laboratory.
Such induced pluripotent stem cells are made in the lab by taking normal adult stem cells, like skin or blood cells, and reprogramming them to become the stem cells.
Induced pluripotent stem cells are pluripotent, just like embryonic stem cells, which means they can develop into any cell type.

Difference between Embryonic stem cell and adult stem cells:

Embryonic stem cells are located in an embryo whereas Adult stem cells are located in different parts on the adult body like bone marrow, and liver.
They are pluripotent whereas Adult stem cells are multipotent.
Embryonic stem cells divide into more cells and gradually form a baby (complete human) whereas Adult stem cells divide and form only specific specialized cells in the body to fulfil the demands of the cells in the body.

STEM CELL LINES:

A stem cell line is a group of cells that all descend from a single original stem cell and are grown in a lab under certain conditions.
Such cells in a stem cell line keep on growing but do not differentiate into any specialized cells.
They are free from genetic defects.
They continue to grow and create more stem cells.
A cluster of cells is taken from a stem cell line and frozen for storage or shared with other researchers for researcher purpose.

The usefulness of Stem cell / Stem cell as an interesting topic:

Many doctors and researchers hope stem cell studies can help to:

> Boost the understanding of how diseases occur:

Doctors and researchers may better understand how diseases and other conditions develop in our body by watching how stem cells grow and mature into different cells in the heart muscle, bones, nerves, and other organs and tissue.

> Replace diseased cells by generating healthy cells (Regenerative Medicine)

Stem cells can change themselves into specific cells. So, by guiding stem cells to become specific cells that can be used to treat certain types of disease and repair damaged tissue in people.

Stem cells have the potential to grow and become new fully grown tissue. So doctors and researchers can use this in transplant and regenerative medicine. Doctors and researchers continue to advance knowledge and technology on stem cells and their application in transplant and regenerative medicine.

Some of the use of stem cells in diseases are:

–>Tissue regeneration:

It means producing new tissue with the help of stem cells. Tissue regeneration would reasonably be the most important use of stem cells.

Till today, a person who needs a kidney for transplantation needs to wait for a donor and then undergo transplantation.

There is a shortage for the donor organs but the number of people needing an organ is still high. So by instructing stem cells in a certain way, scientists could potentially be able to grow a specific tissue or organ.

For example, doctors have successfully used stem cells from just below the skin’s surface to make new skin tissue. These tissues could be used to repair a severe burn or another injury by grafting the tissue onto the damaged skin, and new tissue will grow back.

–> Treatment of Cardiovascular disease:

A team of researchers from Massachusetts General Hospital, in 2013, reported in PNAS Early Edition that they had created blood vessels in laboratory mice, using human stem cells.

Networks of blood perfused vessels had formed, within 2 weeks of implanting the stem cells. The quality of the blood vessels was nearly the same as the natural ones.

Researchers hope that this type of implantation technique could in the future treat people with cardiovascular and vascular diseases.

–> Treatment of Brain Disease:

Diseases such as Parkinson’s and Alzheimer’s could be treated with the help of stem cells by replacing the cells or tissues.

For example, in Parkinson’s, there’s uncontrolled muscle movement due to damaged brain cells. So scientists could treat the disease by replacing the damaged cells with the stem cells. This could stop uncontrolled muscle movement by bringing back the specialized brain cells.

Many researchers have already tried differentiating embryonic stem into these types of cells, so results are promising.

Stem Cell For Research

Source of stem cell for research:

There are four main sources of stem cell for research, they are:
1. Embryonic stem cells
2. Adult stem cells
3. Induced pluripotent stem cells
4. Perinatal stem cells

Embryonic stem cells:

These stem cells come from 3-5 days old embryos. 3-5 days old embryo is called a blastocyst and has about 150 cells. These are pluripotent (ability to become any cells on the body). Due to this feature, an embryonic stem cell can be used to repair diseased tissues and organs.

Adult stem cells:

These stem cells come from adult tissue, such as bone marrow or fat. They are comparably found in less number in adult tissue. Such stem cells have less or limited ability to give rise to various cells of the body.

Adult stem cells research, until recently, researchers believed that adult stem cells could create only similar types of cells, such as stem cells in the bone marrow could give rise to only blood cells.

However, recently the researchers found that adult stem cells may be able to create various cells in the body. For example, stem cells in the bone marrow may be able to give rise to heart muscle cells or one cell.

This emerging research has led to many early-stage clinical trials to test usefulness and safety in people. For instance, people with neurological or heart disease are being tested with adult stem cells.

Induced Pluripotent Stem Cells:

These cells are created in a lab by altering the adult stem cells to have the properties of embryonic stem cells.

This new technique of creation of embryonic stem cells may allow researchers to prevent immune system rejection of the new stem cells.

However, scientists are yet not sure whether using altered adult stem cell (induced pluripotent stem cell) will cause any adverse effects in the human.

Perinatal stem cells:

These are the stem cells found in the amniotic fluid as well as umbilical cord blood. These stem cells can change into specialized cells like embryonic stem cells.

Amniotic fluid is present in the sac that surrounds and protects a developing fetus in the uterus. Researchers identified stem cells in the sample from amniotic fluids drawn from pregnant women to test for abnormalities in the growing fetus (baby)- a process called amniocentesis.

More research is needed in amniotic fluid stem cells to understand their full potential.

Embryonic Stem Cell and its Controversy:

Embryonic stem cells are obtained from 3-5 days old embryos- a group of cells that are formed when women’s egg and men’s sperm get fertilized in vitro fertilization clinic.
Since embryonic stem cells are obtained from a human embryo, so many questions are raised about the ethics of embryonic stem cell research.
In 2009, guidelines for human stem cell research was created by The National Institutes Of Health.
The guidelines clearly define embryonic stem cells and how they may be used in research.
The guidelines include the recommendation for the donation of embryonic stem cells.
It is clearly stated in the guidelines that embryonic stem cells from embryos created in vitro fertilization can be used when the embryo is no longer needed.

Where do the stem cells for research come from?

Stem cells for research come from embryos that are fertilized in vitro fertilization clinics but were never implanted in a woman’s uterus.
With the permission of the donor, stem cells are even donated for research purposes.
Such embryonic stem cells can live and grow in special solutions in the laboratories.
Adult stem cells could be used instead of embryonic stem cells, but adult stem cells are not that promising yet.
Adult stem cells may not be able to reprogram into any specialized cells, which limits how stem cells can be used to treat diseases.
Many abnormalities are found in adult stem cells due to environmental hazards, such as toxins, or form error acquired by the cells during replication.
But, researchers have found that adult stem cells are more promising and adaptable than was first thought.

Stem Cell For Therapy/Medicine

Is there any disease that has been treated with stem cells?

Yes, doctors have performed stem cell transplantation, also known as bone marrow transplantation.
In stem cell transplantation (bone marrow transplantation), stem cells replace damaged cells by chemotherapy or serve as a way for the donor’s immune system to fight some types of cancer, such as leukemia, lymphoma, and neuroblastoma.
Such transplantation uses umbilical cord blood or adult stem cells.
Research is ongoing for the testing of adult stem cells to treat other conditions, including several degenerative diseases such as heart failure.

Stem cell therapy (Regenerative Medicine)

Stem therapy or regenerative medicine promotes the repair function of disease, dysfunction, or injured tissue using stem cells.
This new chapter of therapy is related to organ transplantation but deals with cell instead of the donor organ which is limited in supply.
Stem cells are grown in the lab.
Stem cells can be reprogramed into any specific cell, such as heart muscle cells, blood cells, or nerve cells.
Such reprogrammed specialized cells can be transplanted into a person. For example, heart disease patients could be transplanted with the reprogrammed stem cell into the heart muscle, which then could contribute to repair defective heart muscle cells.
Researchers have successfully been able to guide adult bone marrow cells to become heart-like cells, which can be used to repair the heart tissue in people. More research is ongoing.

Problems with using Embryonic stem cells:

Embryonic stem cells can change into any type of specialized cell spontaneously and also grows irregularly.
Researchers must be able to control the growth and differentiation of embryonic stem cells.
Though embryonic stem cells may be useful in people, researchers must be certain that the stem cell would change into the desired specific cells.
Researchers have successfully been able to change embryonic stem cells into heart cells. Researchers are ongoing in this field.
Embryonic stem cells might also trigger the immune response, which the recipient’s body attack as foreign invaders. This might simply lead to failure in the normal function of the stem cells.
Research is ongoing to avoid the possible consequences of the embryonic stem cells.

Therapeutic Cloning:

Therapeutic cloning also called somatic cell nuclear transfer.
In this technique, the versatile stem cell-independent of a fertilized egg is created.
First, the nucleus, which contains genetic material is removed from an unfertilized egg.
Then, the nucleus is remover from the cell of the donor.
Now, the nucleus of the donor cell is injected into the egg, replacing that was removed, in the process called nuclear transfer.
After the nuclear transfer is completed, the egg is allowed to divide and form a blastocyst.
This forms a line of stem cells that has the identical genetic character to the donor’s cells- a clone.
Some researchers believe that stem cells derived from therapeutic cloning have less chance to get rejected by the body, and once transplanted back into the donor may allow researchers to see exactly how a disease develops.
Yet, there is no successful case of therapeutic cloning in the people despite success in several other species.
Recently, researchers successfully created pluripotent stem cells by modifying the therapeutic cloning process.
Researches are ongoing in this field and someday researchers may successfully do therapeutic cloning in people.