Stem Cells | Bedomaich Chayi | Public Cord Blood Bank

Cord blood is unique in its richness of stem cells, which can be used for bone marrow transplants to treat various diseases. By definition, stem cells are cells that haven't yet differentiated and can continue to split identical cells as well as differentiate and grow a diverse range of specialized cells, each with their special characteristics suited to its 'job'.

An embryo begins its 'life' as a single cell, a zygote that within a few hours will split into identical cells. These first embryonic cells are Totipotent Stem Cells – stem cells that can differentiate all the different cells in an organism. These cells will also split and within a few days a blastocyst can be seen, which is divided into two types: inner cell mass from which the fetus will develop or outer trophoblasts which make up the placenta. These are Pluripotent Stem Cells, developed stem cells which can no longer differentiate to produce fetus cells but will develop other cells.

As the fetus grows, the cells differentiate into more specialized cells, Multipotent Stem Cells. Hematopoietic stem cells are multipotent, and produce the blood cells (red blood cells, white blood cells, platelets and more). With the progression of the pregnancy, the fetus' stem cells are produced in the liver and spleen and from there they join the bloodstream. After birth, the blood's stem cells move to the bone marrow where they continue to produce all the necessary blood cells the body needs in order to function properly. At birth, after the cutting of the umbilical cord, hundreds of millions stem cells can be collected in the blood left in the umbilical cord and placenta. They can easily be saved for future use in a blood marrow transplant.

Blood stem cell play a critical role in a person's life. A baby after he is born, as well as an adult, blood cell production takes place in the bone marrow – the spongy tissue located in cavities of large bones. This tissue contains hematopoietic stem cells, which produce blood cells, as needed all your life. Three million new blood cells are produced in the bone marrow every second! These cells mature and then move into the bloodstream.
 

The main components in the blood are:

Red Blood Cells - (also referred to as erythrocytes) are the main component of the blood and also give it its color. Their main functions are: delivering oxygen from the lungs to the body's tissues and carrying carbon dioxide from the cells back to the lungs. The gasses are bound to the hemoglobin molecules present in the red blood cells. They are the only cells that do not have nuclei and therefore do not carry DNA. Their functional lifetime is about 120 days.

White Blood Cells - (also referred to as leukocytes) are the main component in the body's immune system. Different types of white blood cells exist each with their own function, such as: identifying 'foreign invader' (infection), attacking and destroying dead or damaged cells in the body. White blood cells play a crucial role in keeping us healthy. Cancer of the blood which harms the white blood cells is called leukemia.

Platelets - (also referred to as thrombocytes) are actually cell fragments and are a part of hemostasis leading to the blood clotting. When there is a tear in a blood vessels, platelets amass there, creating a 'plug' which blocks the hole and secretes clotting factors which stimulate the rest of the clotting and healing process. Platelets have a short lifespan of a week to 10 days.

Sometimes, the bone marrow malfunctions and produces an increased amount of damaged cells. This is leukemia. As the disease spreads, the malignant cells crowd the healthy cells, spilling over to the bloodstream, affecting the body's organs and endangering a person's life. Leukemia is treated with chemotherapy, radiation, bone marrow transplants and other progressive biological treatments.
 

Non-hematopoietic Stem Cells

Although this topic isn't directly related to today's use of cord blood, we've chosen to expound on non-hematopoietic stem cells because of the interest in this topic and its relation to cord blood.
 

Embryonic stem cells

Embryonic stem cells are pluripotent and have the ability to replicate indefinitely. Therefore they are the preferred source for use in research in this field, for understanding the process and finding new cures for various illnesses. Use of embryonic stem cells raises complex ethical, legal and halachic issues. In specific countries, embryonic stem cell research is forbidden and in others is subject to various limitations. As of today, there is no practical use for embryonic stem cells.
 

Mesenchymal stem cells

Mesenchymal stem cells are multipotent stem cells and can be derived from the bone marrow, cord blood and other body tissues. These cells can differentiate to different cell types (muscle cells, bone cells, nerve cells and more) and researchers pin great hopes on future development in cell therapy and regenerative medicine which will  treat many sicknesses, such as diabetes, Parkinson's, spinal injuries, heart disease and more.

Researchers hope to find the way to stimulate mesenchymal stem cells to differentiate to the specific cell type and function needed for treatment without risking an increase in cell splitting leading to cancerous cells. There is no estimate for when there will be clinical use for mesenchymal cells and if this will be the preferred source when needed. When they will be able to be used for treatment, the cells can be gotten from the patient himself, from the bone marrow or fat cells or from existing cord blood donations. Anticipating future use for mesenchymal stem cells, does not justify – according to doctor's recommendations – preserving cord blood for oneself. It is also unclear if one will be able to use these stem cells from cord blood after being in a deep freeze for a long time.