Stem cells

The history of medical research and application of stem cells goes back over a hundred years. During this time, science has made great strides from identification of these unique cells to treatment of seemingly incurable diseases, sports therapy and regeneration of tissues and entire organs.

Diseases for which stem cells are already used or planned to be used:

• Lymphoma
• Tissue regeneration (skin tissues that are created with stem cells to treat burns and skin injuries; creation of cartilage tissue and even individual organs)
• Treatment of cardiovascular diseases (in 2013, a group of researchers from Massachusetts General Hospital conducted successful experiments to create blood vessels in laboratory mice)
• Treatment of brain diseases (e.g., Alzheimer's and Parkinson's disease)
• Cell deficiency therapy (researchers expect labs to be able to create healthy heart cells that can be transplanted into people with heart disease)
• Treatment of Diabetes I (stem cells will be used to replace the cells that produce insulin).
• Treatment of blood diseases (stem cells are already being actively used to treat diseases such as leukemia, sickle cell anemia, and other immunodeficiency disorders).- Treatment of sports injuries
• Anti-aging therapy
• Rehabilitation treatment after COVID-19

Stem cells are a special kind of cell that can transform into different types of cells and thus help the body to repair itself.

Stem cells differ from other cells in the body in three ways:

• They can divide and renew over a long period of time.
• They are unspecialized, so they cannot perform certain functions in the body
• They can potentially become specialized cells. For example: muscle, blood or brain cells.
• No other cells in the body have the natural ability to generate new cell types.

Stem cells have great potential for study and application in medicine. It is predicted that further study of stem cells will enable scientists not only to better cope with diseases, but also to study the causes and development of certain diseases. Work with stem cells also provides opportunities to test a wide range of drugs without risking human lives.

The topic of stem cells is very broad, but we will try to answer some of the most frequently asked questions.

Where do stem cells come from?

Depending on the source, stem cells are divided into:

• Embryonic stem cells.
• Adult stem cells

EMBRYONIC STEM CELLS

The name of these cells speaks for itself. Indeed, this type of cells is considered to be the most promising, but it raises a lot of ethical controversy, since the cells are taken from embryos. On day 3-5, after the successful fertilization of an egg in the laboratory, a blastocyst is formed, serving as a donor of embryonic stem cells.

The blastocyst consists of two parts:

• The outer cell mass.
• The inner cell mass.

The inner cell mass is the source of embryonic stem cells (about 150 cells). When properly stimulated, these cells can become blood cells, skin cells, and all the other types of cells the body needs. This versatility allows embryonic stem cells to be used to regenerate or repair diseased tissues and organs.

Where do embryos for embryonic stem cell extraction come from?

It is important to understand that these embryos are donated to science by donors and are never implanted into a woman's uterus for further development. Stem cells are donated with the informed consent of the donors. Stem cells can live and grow in special solutions in test tubes or petri dishes in laboratories.

Why is the use of embryonic stem cells controversial?

Embryonic stem cells cause a lot of controversy on several counts at once:

• Embryo. There is still some uncertainty about at what stage a fertilized egg can be considered a child. And the use of the blastocyst, for stem cell extraction, is condemned in some countries.
• IVF. The embryo, which acts as a cell donor, is created in the laboratory through in vitro fertilization.  Despite the high efficiency of this procedure, there is still a huge number of people in the world who oppose artificial insemination.

To regulate the process of obtaining and using embryonic stem cells, the National Institutes of Health developed guidelines for human stem cell research in 2009. The guide defines embryonic stem cells and their use in research and provides recommendations for embryonic stem cell donation. In addition, the manual states that embryonic stem cells from embryos created by in vitro fertilization can be used only when an embryo is no longer needed.

ADULT STEM CELLS

Most adult tissues contain stem cells; however, they may be inactive and difficult to detect. Despite the seemingly advantageous position of adult stem cells, as their removal is devoid of most ethical conflicts, the difficulty is that they are inferior in their productivity to embryonic stem cells. Adult cells are more limited in their ability to give rise to various cells in the body.

Relatively recently, scientists have succeeded in debunking the myth that adult stem cells can only create similar types of cells. For a long time, for example, it was thought that stem cells living in the bone marrow could only give rise to blood cells.

Currently, the use of adult stem cells is very extensive and involves such fields as neurology and cardiology.

In 2006 there was a turning point in the study of stem cells - the possibility of genetic programming of adult cells was announced.

Induced pluripotent stem cells (iPS). These are adult stem cells that have been altered in the laboratory to become more similar to embryonic stem cells. They do not differ in appearance from embryonic stem cells, but scientists have not yet found one that can develop all types of cells and tissues.

Sources of adult stem cells

• brain
• bone marrow
• blood and blood vessels
• skeletal muscles
• skin
• liver

Adult stem cells can divide or self-renew indefinitely. This means that they can generate different cell types from the original organ or even completely regenerate the original organ.

Thanks to such division and regeneration, a skin wound is healed or an organ, such as the liver, is repaired after an injury.

Mesenchymal stem cells (MSCs)

Another type of stem cell that comes from the connective tissue or stroma that surrounds organs and other body tissues.
Scientists use them to create new body tissues: bone, cartilage, and fat cells. Perhaps one day they will play a role in solving a wide range of health problems.

Perinatal stem cells

In addition, scientists have discovered and are using stem cells from amniotic fluid and umbilical cord blood in research. These stem cells have the ability to turn into specialized cells.

Amniotic fluid fills the sac that surrounds and protects the developing fetus in utero. Researchers found stem cells in samples of amniotic fluid taken from pregnant women for testing or treatment, a procedure called amniocentesis.

Why can't researchers use only adult stem cells instead of embryonic cells?

Two main reasons can be identified:

First, the ability to manipulate adult cells is limited because they cannot reproduce all cell types. In addition, they are not as durable.

Secondly, the probability of abnormalities in such cells, due to the environment, bad habits, diseases experienced and other things is much higher.

What other types of stem cells are there?    

The full classification includes:

• Totipotent: These stem cells can differentiate into all possible cell types. The first few cells that appear when a zygote begins to divide are totipotent.
• Pluripotent: These cells can turn into almost any cell. Cells from the early embryo are pluripotent.
• Multipotent: These cells can differentiate into a closely related family of cells. For example, adult hematopoietic stem cells can turn into red and white blood cells or platelets.
• Oligopotent: They can differentiate into several different cell types. Adult lymphoid or myeloid stem cells can do this.
• Unipotent: They can produce only one type of cell, that is, their own type. However, they are still stem cells because they can self-renew. An example of this is adult muscle stem cells.

Is stem cell therapy successful?

The most popular and well-known use of stem cells is in bone marrow transplantation. In a stem cell transplant, stem cells replace cells damaged by chemotherapy or disease, or provide a means for the donor's immune system to fight certain cancers and blood-related diseases such as leukemia, lymphoma, neuroblastoma and multiple myeloma. Adult stem cells or cord blood are used for these transplants.

Adult stem cells have been shown to be highly effective in treating other diseases, including a number of degenerative diseases such as heart failure.

How are adult stem cells taken?

You can become a donor for a loved one or for yourself in the future. Or you can use the cells provided at the clinic.

Adult stem cells can be obtained from the following sources:

Bone marrow: These cells are taken under general anesthesia, usually from the hip or pelvic bone. Specialists then isolate stem cells from the bone marrow for storage or donation.

Peripheral Stem Cells: A person is given several injections that cause the bone marrow to release stem cells into the blood. The blood is then drawn from the body, a machine separates the stem cells, and doctors return the blood to the body.

Umbilical cord blood: Stem cells can be harvested from the umbilical cord after delivery without harming the baby. Some people donate umbilical cord blood and others store it.

Stem cells are the future of modern medicine. Already today they show impressive results of treatment and therapy. We can only speculate how medicine will change when all the possibilities of stem cell use are fully understood.

You can learn more about stem cells in one of our clinics or from UAmedTOURS manager.