What are Stem Cells?What are Stem Cells?

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What are Stem Cells?

The first person to use the term “stem cell” was William Sedgwick in 1886. Earlier, scientists experimented in the plants and gradually, they performed a set of experiments in the animals for further studies.

Stem cells are pluripotent cells that have the ability to differentiate into multiple kinds of cells (a muscle cell, a red blood cell or any other). When a stem cell divides, it can make any one of the 220 different cells in the human body.

It’s why these are also called ‘blank cells’. Many potential uses of stem cells make it an interesting line of study for researchers, scientists and medical enthusiasts. A plethora of genetic disorders and diseases may be cured depending upon the line of origin of the stem cells. Some of the areas where stem cells are used in the treatment include spinal cord injuries, age-related macular degeneration, diabetes, AIDS and Parkinson’s disease.

Classification of Stem Cells

Various sources and types of stem cells exist on which the uses of stem cells depend upon. Let us contemplate the following chart to understand the different types of stem cells.

Based on Their Origin Based on Stages of Development
  1. Embryonic Stem Cells
  2. Fetal Stem Cells
  3. Umbilical Cord Stem Cells
  4. Adult Stem Cells
  1. Pluripotent Stem Cells
  2. Multipotent Stem Cells
  3. Totipotent Stem Cells
  4. Inducible pluripotent Stem Cells

Types of Stem Cells Based on their Origin

Embryonic Stem Cells

The sources of the embryonic stem cells are human embryos that are three-five days old post-fertilization (during the blastocyst stage). These are pluripotent and are harvested via in-vitro fertilization due to ethical issues, i.e. fertilising an embryo in a laboratory rather than inside the female body. The pluripotency of stem cells is explained further in this article. Other properties of these cells include self-renewal (unspecialized state), repair of structure and growth, or rapid cell division.

Embryonic stem cells have therapeutic properties in clinical use as well and are extensively considered/used for the treatment of diabetes and heart diseases.

Fetal Stem Cells

Fetal blood and bone marrow including other fetal tissues such as the liver and kidney can be the source of the fetal stem cells. Fetal blood contains hematopoietic stem cells (HSC) and these proliferate more rapidly than those present in adult bone marrow or cord blood. Non-hematopoietic mesenchymal stem cells (MSC) are also present in the first-trimester fetal blood that supports haemopoiesis and differentiate along multiple lineages. Fetal stem cells have been known for better intrinsic engraftment, multipotentiality and lower immunogenicity as compared to adult stem cells.

Umbilical Cord Stem Cells

The type of stem cells which are harvested from the umbilical cord after childbirth are cord blood stem cells. These kinds of cells can be preserved in cell banks for future use. Numerous diseases such as blood cancers and genetic blood disorders have found hopes for treatment with the umbilical cord blood stem cells.

Adult Stem Cells

Adult stem cells don’t necessarily mean the ones which are present only in adults since these are also found in children and infants. Adult stem cells refer to those which come from developed organs and tissues in the body. Extremely useful in repairing and replacing damaged tissue in the area based on its origin, these cells are quite famous. An example is hematopoietic stem cells found in the bone marrow.

Types of Stem Cells Based on the Stages of Development

Pluripotent Stem Cells

Pluripotent cells include embryonic stem cells as these can develop into any type of cell except those of the placenta. Other examples include cells formed during the early stages of embryonic stem cell differentiation as well as the cells derived from the germ layers like mesoderm, ectoderm and endoderm.

Multipotent Stem Cells

Multipotent stem cells have the ability to divide into closely-related cells. Some of the examples include hematopoietic stem cells (which develop into RBCs, WBCs and platelets), oligopotent cells such as lymphoid or myeloid stem cells (which develop into a few cell types) and muscle stem cells (which develop into cells of their type).

Totipotent Stem Cells

Cells that can differentiate into all types of cells are known as totipotent stem cells. One of the best examples is embryonic stem cells of the morula stage or the zygote formed during the fertilization of an egg and a few cells after division as these can develop into any type of cell including that of the placenta.

Inducible Pluripotent Stem Cells

Scientists worked into this new category of stem cells originating from somatic cells which can be reprogrammed back to their pluripotent stage. It was done after manipulating the expression of a set of genes. These stem cells are fetched from umbilical cord blood or a foetus. The reprogrammed cells are known as induced pluripotent stem cells, abbreviated as iPS cells.

Sources of Stem Cells

Stem cells can be obtained from a foetus, umbilical cord, embryo, bone marrow or other tissues of the body. Bone marrow stem cells are also popular and these come from deep within the bone, such as hip bone. Once the blood cells from the stem cells mature in the bone marrow, they enter the bloodstream, a few immature blood cells may also enter the bloodstream. The umbilical cord is one of the most effective sources of stem cells that has been protecting numerous families together with cord blood banking techniques and stem cells preservation. Tooth tissue engineering is one of the potential treatment areas where scientists make use of dental stem cells, isolated from dental pulp and the periodontal ligament. Therefore, we can say that stem cells are present in different parts of the body and are one of the finest ways of treatment for rare diseases. Let us understand the sources of stem cells at a greater length:

Adipose Tissue

Mesenchymal stem cells that are derived from the adipose tissue have the potential for self-renewal and multipotency. These can differentiate into varied categories of cells including adipocytes, myocytes, chondrocytes, osteoblasts, and neurocytes. Medical enthusiasts have found its critical role in reconstructive and tissue engineering fields for the development of newer treatment possibilities.

Bone Marrow

The center of bones comprises a soft gelatinous tissue known as bone marrow. It is known that mesenchymal stem cells, hematopoietic or blood stem cells are found in the bone marrow. All of these stem cells are interesting components for regenerative medicine and therapeutic purposes.

Amniotic fluid

The liquid surrounding the amnion or the sac supporting the foetus is called amniotic fluid. Embryonic stem cells are found in both the amniotic membrane and the amniotic fluid and can multiply to form any kind of cell. Recent medical advancement has resulted in its optimum utilisation where the fluid and the membrane are often cryopreserved or frozen for future healthcare usage.

Umbilical Cord Blood (UCB)

UCB is a source of the rare but precious primitive hematopoietic stem cells (HSC) and progenitor cells, including immune system cells. The umbilical cord and placenta of a newborn child contain cord blood which is collected and stored for stem cell banking that helps protect a person from over 80 diseases.

Dental Pulp

Dental pulp or teeth are the most natural and non-invasive source of stem cells. It is easy, affordable and convenient to collect dental stem cells. Tooth tissue engineering helps in restoring the damaged dental tissue or replacing a missing tooth via dental stem cells isolated from the dental pulp or the periodontal ligament.

Which Stem Cells are Effective for Transplantation?

Transplantation is a medical procedure that involves transplanting healthy stem cells into your bone marrow or your blood. It helps in restoring the body’s ability to function well. Different types of blood cells, including new red blood cells and white blood cells emerge from adult stem cells and hence are used for transplantation. Bone marrow transplants (especially using stem cells present in the hip/pelvis) have been successfully performed using hematopoietic stem cells to treat wide cancerous diseases. Besides, Umbilical cord blood and stem cells from newborn babies have been catching great attention for effective transplantation. Therefore, we can say that the following stem cells are the most effective for transplantation:

  1. Bone Marrow Stem Cells
  2. Peripheral Blood Stem Cells
  3. Umbilical Cord Blood Stem Cells from Newborns

The topic of interest is umbilical cord blood stem cells from newborns, an immensely beneficial but often neglected by most parents. Newborn babies carry numerous stem cells; many are present in the placenta and umbilical cord blood after birth. The stem cells can be extracted from the cord blood that can be used in stem cell transplantation whenever required. For years, cord blood can be stored in a frozen state for later use until needed. Umbilical cord blood banking A.K.A stem cell banking is a harmless procedure for the baby and the cord blood stem cell can form more blood cells than one from adult bone marrow.

Uses of Stem Cells: Besides transplantation, cell therapies, gene therapy techniques, and toxicology testing of new drugs make use of stem cells. It makes possible the treatment of and management of varied diseases.

To preserve your baby’s life-saving umbilical cord stem cells and protect your entire family against over 80 diseases, visit BabyCord or talk to our experts @ 18002665533

As we have explained in detail the different types and sources of stem cells in this article, its right utilization and actions for securing health on time are necessary. LifeCell offers pocket-friendly packages to preserve your baby’s umbilical cord blood that helps in safeguarding the baby’s and family’s future.

References:

  1. Maienschein J. (1) Whose view of life? Cambridge: Harvard University Press; 2009. pp. 58–70. [Google Scholar]
  2. Watson S. How stem cells works. 2017. [cited 12 March 2019]. Available from: https://science.howstuffworks.com/life/cellularmicroscopic/stem-cell1.htm.
  3. "Introduction: What are stem cells, and why are they important?". National Institutes of Health. Retrieved 28 October 2018.
  4. Heurtier, V., Owens, N., Gonzalez, I. et al. The molecular logic of Nanog-induced self-renewal in mouse embryonic stem cells. Nat Commun 10, 1109 (2019). Available from: https://doi.org/10.1038/s41467-019-09041-z