Stem cells are special types of cells that can regenerate and repair cells, tissues, and organs of the body. How are they different from the other cells of our body? Stem cells have not yet differentiated into a specific type of cell, which is why they can divide and develop into many different cell lineages. Additionally, they can constantly divide and renew themselves. The two major categories that researchers are concerned with are adult stem cells and embryonic stem cells. Adult stem cells are multipotent, which means that they can differentiate into a specific type of tissue since they have already committed to one particular lineage. On the other hand, embryonic stem cells are pluripotent. Thus, they can divide into all the cell types of the mature human body. This property of embryonic stem cells makes them especially useful for studying the regeneration of many forms of specialized tissues.
There are a few ethical issues surrounding the decision to use stem cells for research. This topic is especially controversial in relation to embryonic stem cells, which are extracted from newly formed human embryos. These stem cells must be removed during the blastocyst stage of cell differentiation, from the inner cell mass. The blastocyst is a hollow collection of cells that is a precursor to the fetus. Removing the inner cell mass will destroy the blastocyst, thus preventing future differentiation and growth. However, scientists have recently quelled much of the ethical concerns, by obtaining stem cells in vitro. This means that the egg is not extracted from the woman’s uterus, and instead, the fertilization of the egg is completed in a laboratory. The egg is obtained from a donor who has given informed consent to the procedures. Thus, these stem cells are cultured in petri dishes, then used specifically for scientific research.
Figure 1: The derivation and application of stem cells.
Regenerative medicine is a significant field under the umbrella of biomedical research. The main objective of this branch of medicine is to generate advancements in the study of repairing and replacing diseased or injured cells of the body. This is especially crucial for the treatment of hematological cancers, which target tissues relating to blood, the immune system, and bone marrow. For example, bone marrow transplants are used to restore the cells that have been damaged by cancer or chemotherapy treatments. Replacing these cells allows the recipient's immune system to become more robust, which can help the person possibly enter into remission. Embryonic stem cells have also been used to study and treat birth defects, and they can possibly be used to treat spinal cord injuries, Alzheimer’s, as well as many other ailments of the human body.
The biomedical research conducted on stem cells is fairly recent, and by minimizing many ethical concerns, scientists continue to discover novel methods of organ regeneration and stem cell therapy. In 2019, Columbia University researchers were able to create two fully functional lungs in mice from their laboratory. In 2021, many double-lung transplants were performed on COVID-19 patients, since respiratory disease can cause complicated lung failure. Thus, this field is extremely relevant, as scientists examine ways in which advances in stem cell research can be applied to the bodies of humans. The possibilities of innovation are boundless, especially when dealing with the incredible biological discipline of stem cells.
Written by: Meghety Manoyan
References:
Columbia University Irving Medical Center. “Stem Cell Transplants Used to Grow Fully Functional Lungs in Mice.” ScienceDaily, 2019, www.sciencedaily.com/releases/2019/11/191107160640.htm#:~:text=Researchers%20have%20used%20transplanted%20stem.
Mayo Clinic. “Stem Cells: Frequently Asked Questions about Stem Cell Research.” Mayo Clinic, 8 June 2019, www.mayoclinic.org/tests-procedures/bone-marrow-transplant/in-depth/stem-cells/art-20048117.
“Stem Cells.” Medlineplus.gov, National Library of Medicine, 2019, medlineplus.gov/stemcells.html.
Yu, Junying, and James A. Thomson. “Embryonic Stem Cells | Stemcells.nih.gov.” Nih.gov, 2016, stemcells.nih.gov/info/Regenerative_Medicine/2006Chapter1.htm.