For decades researchers have been saying that stem cells hold a lot of promise for the future. And they are now beginning to be proved right.
But where do these stem cells come from? And why are they so special? And why do we need to store them through cord blood banking? We have all the answers to your queries.
What is Stem Cell?
Stem cells are undifferentiated cells within the body that has the ability to differentiate into specialized cells. They divide through a process called mitosis to produce more stem cells.
Stem cells are found in all multicellular organisms.
In mammals stem cells are mainly of two types.
- Embryonic stem cells – these are found in the inner mass of cells in blastocysts. In the embryo the stem cells differentiate to form all the specialized cells and also regenerative organs like blood and skin.
- Adult stem cells – these are found in different tissues. The stem cells in the adult body repairs and replenish the damaged tissues.
Uniqueness of Stem Cells
Stem cells are different from other kinds of cells in the body.
All stem cells have three distinguishable properties that make them different.
- They can divide and renew themselves
- They are unspecialized
- They can form themselves into specialized cells
Stem Cells can Divide and Renew Themselves
Muscle, blood and nerve cells cannot replicate themselves. But stem cells can.
If a population of stem cells is kept in the laboratory they have the ability to replicate themselves many times. This is called proliferation.
During proliferation the stem cells can continue to remain unspecialized. This makes them capable of long-term proliferation.
Usually it is the embryonic stem cells that can proliferate without differentiating themselves for even up to a year. Adult stem cells cannot. Scientists are trying to understand why this is so.
Stem Cells are Unspecialized
Stem cells do not have any specific tissue structures. And so it does not perform any particular specialized function.
Stem Cells can Form Themselves into Specialized Cells
When unspecialized stem form themselves into specialized cells it is called differentiation.
Differentiation occurs due to both internal and external signals that the cell receives.
- The internal signals within the cell is controlled by a cell’s genes
- The external signals are chemicals that other neighboring cells secrete.
Adult stem cells usually differentiate themselves into specialized types depending on which tissue type they reside in within the body. For example, a stem cell from the bone marrow (called a hematopoietic stem cell) will form a blood forming cell and not a nerve cell of the brain.
Different Types of Stem Cells
Stem cells can be classified into different types based on where they are obtained.
Embryonic Stem Cells:
Human embryos form a blastocyst 4-5 days after fertilization. Embryonic stem cells are obtained from the inner cell mass of a blastocyst.
This type of stem cell has the ability to differentiate into nearly all types of specialized cells. Theoretically this makes them a potential source for regenerative medical treatments in the future. But currently no approved treatments using embryonic stem cells exist.
Fetal Stem Cells:
Fetal stem cells are found in the organs of fetuses.
They are either obtained from the fetus proper after an abortion or from extra-embryonic membranes of the fetus.
Adult Stem Cells:
Adult stem cells are found both in children as well as in adults.
They repair the tissue in which they are found.
Bone marrow is a rich source of adult stem cells. Such stem cells have been used to treat spinal cord injuries and even heart failures. Their quantity declines with age and are usually more in number in males than in females.
Amniotic Stem Cells:
The amniotic fluid contains such stem cells.These kinds of cells, due to their easily expanding property is widely used in research.
Induced Pluripotent Stem Cells:
These are adult cells that have been reprogrammed to form stem cells.
Stem Cell Treatment
Stem cells are being used in the treatment of different diseases. Bone marrow transplants are the most widely used form of stem cell therapy. It is very recently that cord blood stem cells are also being used.
Research is being conducted on whether it can successfully treat brain damages like Parkinson’s and Alzheimer’s.
Another active area of research is using stem cells for cardiac repair for cases like hypertension, strokes and heart failures. Scientists are trying to generate new heart muscles and stimulate the growth of new blood vessels using various research methods.
Hair follicles also contain stem cells. Some believe that stem cell treatment can be effectively used to cure baldness too!
Theoretically scientists feel that stem cells from a patient can be coaxed into a tooth bud which when implanted into the gum can result in a new tooth to grow. Research is under way for the same. 2004 saw scientists in London laboratory creating a full tooth in a mouse using stem cells.
Research is on to use stem cell treatment to treat other disease like:
- Orthopedic care
Stem Cell Banking
What is Stem Cell Banking?
The stem cells from the cord blood and cord tissue can be easily collected, processed and preserved for future use. The process of doing so is called stem cell banking.
Stem Cell Collection:
Post birth, cord blood stem cell collection is done by clamping and cutting the umbilical cord first.
If there is a delay of more than a couple of minute in clamping and cutting the cord then all the cord blood will clot. And once the blood clots, then you can’t use it.
After that a needle is inserted into the umbilical vein of the cord that is still attached to the placenta. But it doesn’t go anywhere near the baby, so don’t worry.
At least 75ml of cord blood is required so that there are enough stem cells to be used for transplantation. Additional stem cells may also be collected from the placenta.
Stem Cell Transport:
A courier then takes the blood to the blood bank. The stem cells are then separated from the rest of the blood in the stem cell laboratory. It is then processed for additional stem cells.
Before storage happens the cord blood undergoes tests for:
- Hepatitis B and C
- Tissue typing to determine Human Leukocyte Antigen type
- Nucleated cell count
- Cell viability
- Blood group
- Bacterial and fungal growth
After the cord blood is processed a cryopreservant is added to the cord blood to allow the cells to survive the cryogenic process.
It is then slowly cooled to −90°C and then added to a liquid nitrogen tank. This keeps it at −196°C.
The slow freezing process keeps the cells alive during the freezing process. The stem cells can be stored for more than 20 years.
For umbilical cord storage usually there are technicians who keep monitoring the temperature and also check on the other safety measures so that none of the samples are ever tampered with.
Stem Cell Processing:
Cord blood has three components – RBC, a whitish liquid called plasma and the component that has the WBCs and the stem cells.
When the banks process the cord blood, it is this last component that is that finally goes into storage. However, of this too, only 1% of it is stem cells.
- RBCs are usually not stored because they have a tendency to burst thereby releasing iron from haemoglobin. This can make the stem cell sample toxic. Removing RBCs also mean removing the blood group and the Rh type. This makes matching easier when the time for stem cell transplant comes.
- The plasma takes up a lot of volume and hence that is also not stored.
Till now there is no process to spate the stem cells from the WBCs.
The separation of the three components is done mainly on account of their different weights. They re usually separated either by sedimentation or by using a centrifuge.
Stem Cell Donation
People usually volunteer to donate stem cells either because they have loved one who needs it or simply because they want to help society.
Potential donors are asked a series of questions to make sure that they are healthy and don’t pose a risk of infecting the recipient.
If you are pregnant then you could also become a stem cell donor by deciding to |bank your child’s cord blood in public cord blood bank. For this, you should make necessary arrangements well before your due date approaches.
You might also be interested in reading:
- Week by Week Guide to Your Pregnancy
- Analyzing Stem Cell Banking Cost in India
- Top 3 Stem Cell Banks in India: Which One Should You Go With?
Research New Treatments
Till now most of the diseases that have been treated using stem cells from the cord blood have been blood related disorders.
However now research is being done to use the stem cells to rebuild cardiac tissues, repair spinal cord injuries and even reverse the effects of diseases such as multiple sclerosis, Alzheimer’s and Parkinson’s.
The clinical trials for these are however still at an early stage. But by banking your baby’s umbilical cord blood you will be helping her to have to these health advancements tomorrow.
The Stem Cell Controversy
The stem cell controversy revolves around the creation, usage, and destruction of human embryos. It involves the usage of embryonic stem cells.
Those opposing embryonic stem cell research compare the process to an abortion. They believe that by using the stem cells and discarding the embryo that could have formed into a human life, science is devaluing human existence.
This group feels that since most transplants are using adult stem cells, there is no need to carry out research using embryonic stem cells.
However, those who are in support for stem cell research say that they are no killing human life because the embryos being used in the research are usually the left over ones from various in vitro fertilizations or from legal abortions.
Fortunately science has begun to come up with alternatives. Stem cell culture is done in which non-embryonic cells are reprogrammed to create a cell that is similar to that of an embryo. This alteration of the cell still produces stem cells but does not generate an embryo.
Hence slowly this debate is becoming irrelevant. But it still has a long way to go.