It’s no secret that stem cells are a revolutionary weapon in medicine, and these special cells can be found in your own body, even your teeth.1
Stem cells have two main defining characteristics: the ability to divide continuously to produce new stem cells and turn them into other body cell types. Most cells in the body are ‘specialized’, which means they can perform different functions, for example, red blood cells are specialized to carry oxygen around the body.2
In medicine, stem cells can be used in disease treatment by replacing damaged cells and tissues.2
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Three Different Stem Cell Origins
The three main types of stem cells are embryonic stem cells, adult stem cells, and induced pluripotent stem cells.2
Embryonic stem cells are categorized as pluripotent stem cells, which means they can change into any cell in the body. These stem cells supply new cells for an embryo as it develops into a baby.2
Adult stem cells are multipotent stem cells, which have less proliferative potential than pluripotent stem cells and can differentiate into some body cells but not all cell types.3
This limited differentiating potential is because adult stem cells have already started to specialize. An example includes hematopoietic stem cells that can only replace various cells within the blood. 2
Induced pluripotent stem cells can be made in the laboratory using normal adult cells such as skin cells, which can be reprogrammed to become stem cells. Inducing stem cell potential in normal cells enables pluripotency, which have the ability to develop into any cell type, similar to embryonic stem cells.2,3
Learn more about Stem Cells
Umbilical Cord Stem Cells
Umbilical cords are the best source of hematopoietic stem cells and mesenchymal stem cells. These have huge regenerative potential for recovering damaged cells and tissues.4
Hematopoietic stem cells within cord blood are responsible for constant renewal of all blood cell types as well as protective immune cells.4
Umbilical cords are usually thrown away during childbirth, however they can be cryopreserved at stem cell banks, either by private or public organizations.4
Public stem cell banks run on donations and perform a thorough screening process using HLA typing, which leads to donated umbilical cord stem cells being available to anyone in need.
In contrast, private stem cell banks offer a more personalized service and provide available cells with donor consent.4
Bone Marrow Registry
Bone marrow consists of soft and spongy tissue that can be found at the center of particular bones in the body, which is where blood stem cells exist. These stem cells produce all essential blood cells, such as red and white blood cells.5
Bone marrow registries are organizations that aid in finding stem cell matches recruiting potential donors that have the potential to be a match for people around the world.5
Being a match to a leukemia patient who may have an ineffective bone marrow means providing a stem cell transplant to rectify their inability to produce essential blood cells. This is usually the best hope for a cure for these patients, who would otherwise have a poor prognosis and high mortality rate.5,6
Joining a registry requires a blood donation, whereby HLA typing or tissue typing is carried out to enable donors to be patched to patients in need.5
Once matched to a patient, there are two possible ways to donate stem cells, including peripheral blood stem cells, whereby a cell-separator machine collects the stem cells from the blood via a vein in one arm and returns the blood through a vein in the other arm.5
The second method is donating bone marrow, which involves removing stem cells from the hip bones using a needle and syringe under general anesthetic in the hospital. This approach requires a 48-hour hospital stay as well as recovery time of up to five days.5
Plants and Animals Have Stem Cells Too!
Plants and animals both stimulate tissue regeneration using either adult stem cells or inducing stem cell differentiation for general life maintenance.7
Tissue regeneration consists of continually renewing biological tissues, re-differentiation of existing adult tissue to produce new organs or for repairing tissue damage.7
Plant stem cells are predominantly found in the meristem, which provides the foundation for the formation of plant organs, ensuring plant growth and development.7
The regenerative capacities of animals and plants differ significantly; amphibians, including salamanders, can completely regenerate lost organs and limbs such as the tail, legs, gills, retina, spinal cord, and heart.
Similarly, zebrafish can also regenerate their hearts and spinal cords, as well as their liver and caudal fin.7
Targeting Cancer Stem Cells
Cancer stem cells (CSCs) can stimulate the production of primary cancer cells, with CSCs carrying characteristics similar to regular stem cells, including their proliferative potential.8
CSCs can sustain cancer by promoting proliferation and cancer growth. By targeting these cells through novel therapies and technologies, cancers can be eliminated at an earlier stage of pathogenesis, leading to successful treatment and long-lasting results.8
A cell marker known as CD-47 usually plays a positive role in healthy cells by protecting them against attacks by macrophages. Unfortunately, in CSCs, the CD-47 protein marker plays a similar role and acts as an immune checkpoint blockade for any attacks by activated macrophages that aim to destroy the cancer stem cells in the tumor microenvironment.8
Therapies that target CD-47 aim to silence its downstream effects. Interestingly, an antibody called Hu5F9-G4 has been developed for this purpose, enabling macrophages to destroy cancer cells.8
A similar antibody called Rituximab works by increasing destruction signals inhibited by CD-47 in CSCs and has been recommended as a first-line single-agent therapy for indolent non-Hodgkin lymphoma.8
Conclusion
The potential of stem cells is monumental for many different applications, especially in medicine.
The ability of stem cells to differentiate into all types of cells in the body provides hope to many researchers investigating diseases and cancer as well as for many patients that are suffering with orphan diseases that do not yet have a cure.3
Additionally, the various sources of stem cells, from umbilical cords to peripheral blood stem cells, provides many sick individuals with poor prognoses to benefit through stem cell transplants.4,5
References
- Hollands P, Aboyeji D, Orcharton M. Dental Pulp Stem Cells in Regenerative Medicine. British Dental Journal. 2018;224(9):747-750. doi:10.1038/sj.bdj.2018.348
- What Is a Stem Cell? Your Genome. Accessed June 2, 2024. https://www.yourgenome.org/theme/what-is-a-stem-cell/#:~:text=A%20stem%20cell%20has%20the%20unique%20ability%20to,have%20been%20damaged%20or%20lost%20due%20to%20disease.
- Rajabzadeh N, Fathi E, Farahzadi R. Stem Cell-based Regenerative Medicine. Stem Cell Investigation. 2019;6:19-19. doi:10.21037/sci.2019.06.04
- Mahla RS. Stem Cells Applications In Regenerative Medicine And Disease Therapeutics. International Journal of Cell Biology. 2016;2016:1-24. doi:10.1155/2016/6940283
- British Bone Marrow Registry. NHS choices. Accessed June 2, 2024. https://www.nhsbt.nhs.uk/british-bone-marrow-registry/.
- Alsulami HA, Alnashri M, Bawazir AF, et al. Prognostics and clinical outcomes in patients diagnosed with acute myeloid leukemia (AML) in a teaching hospital. Cureus. Published online October 20, 2021. doi:10.7759/cureus.18915
- Liu L, Qiu L, Zhu Y, et al. Comparisons between plant and animal stem cells regarding regeneration potential and application. International Journal of Molecular Sciences. 2023;24(5):4392. doi:10.3390/ijms24054392
- Hayat H, Hayat H, Dwan BF, Gudi M, Bishop JO, Wang P. A concise review: The Role of Stem Cells in Cancer Progression and Therapy. OncoTargets and Therapy. 2021;Volume 14:2761-2772. doi:10.2147/ott.s260391
Further Reading
The Role of Neural Crest Stem Cells in Cellular Reprogramming