Stem Cells and Their Application in Medicine

July 5, 2023

Audrey Tran

10th Grade

Fountain Valley High School

What Are Stem Cells?

The human body consists of 200 different types of cells. All cells, ranging from blood cells to nerve cells, originated from the stem cell. Stem cells are cells that have yet to differentiate into a specific function, much like a body’s raw materials. These cells do not have particular tissue characteristics; however, they can later differentiate into numerous specialized cells and tissues. Unlike most body cells that divide for a limited amount of time, stem cells can divide indefinitely. Due to the versatile nature of stem cells, they hold the remarkable potential to be clinically applied in therapies and organ transplantation. 

Types of Stem Cells

There are two main categories of stem cells: pluripotent stem cells (embryonic or induced) and adult stem cells. Embryonic stem cells originate from embryos at the blastocyst stage, around four to seven days after fertilization, and they remain in the inner cell mass. These cells are pluripotent, thus they can differentiate into any cell type and are ideal for use in regenerative medicine. However, there are many ethical issues regarding the use of pre-implanted embryos as the process of removing stem cells from the embryo destroys it.

  Adult stem cells reside in many of the body’s organs and tissues like bone marrow and fat, and are used when the body needs to replenish cells after injury or disease. Unlike embryonic stem cells, adult stem cells do not express pluripotency and can only differentiate into specialized cells of the same tissue origin. For instance, stem cells in bone marrow can produce only red blood cells which makes the use of adult stem cells in medicine extremely limited. Adult stem cells also harbor the risk of mutations obtained over time by cell replication, or toxins from environmental factors. Still, scientists have been able to induce pluripotency into adult stem cells, reprogramming them in an embryonic state, by changing their genetic makeup. These induced pluripotent stem cells (iPSCs) remove the ethical concern of using embryos and allow adult stem cells to be more suitable in clinical applications.

How Can Stem Cells Be Used?

The versatile qualities of stem cells open numerous pathways for them to be used in biomedical research, clinical trials, cell therapies, and organ transplants. Using iPSCs scientists can produce a cell culture on a petri dish and then use a variety of gene editing techniques to differentiate the iPSCs into a desired cell type. These cell masses can be cultured with chemical signals that act as instructions, to coax the differentiated cells to arrange themselves to form more complex structures such as tissue chips and organoids. Tissue chips and organoids are models that represent the physiological architecture and functions of tissues and organs in the body at a much smaller and atomically simpler scale. 

Scientists can observe these models and understand more about cell behaviors and the process of cell differentiation and maturation. From stem cell cultures, it can also be observed how diseases and tumors can arise from genetic mutations in a cell population over time. iPSC cultures are extremely useful in clinical trials, as new drugs and medications can be safely tested on these cell masses in a laboratory setting before being tested in animal or human trials. This removes the need for animal testing which can be inhumane and provides a more accurate trial instead by using human cells. 

Furthermore, iPSCs and adult stem cells can be used in cell therapies and regenerative medicine to be transplanted and replace damaged or dysfunctional cells as well as prompt the body’s natural healing processes. Since stem cells can be extracted from the patient in need of cell therapy, immune rejection will not occur, as the cells originate from the patient, and immunosuppressive medicine is not necessary. Both adult stem cells and iPSCs eliminate the risk of immune rejection from the body, in which the immune system will not identify the transplant as a foreign object. iPSCs can regenerate infinitely unlike adult stem cells which allow for large quantities of stem cells to be generated easier for transplantation. Stem cell transplants have been used to regenerate skin and tissues in burn victims and to repair damaged heart tissues after a heart attack. 

Although still in its early stages of development, iPSCs hold much potential to be used in organ transplantation. Due to the lack of available and accessible organs and the difficulties of matching an existing organ to a patient’s blood type, size, antigens, etc., it is rare that a patient with a dysfunctional organ will find an organ match. iPSCs present a much more ideal alternative than a donor organ because the cells that make up the organ originate from the patient which prevents immune rejection and the organ is more personalized in matters of blood type and size for the patient. However, the current atomically simple cultures of organoids lack the capability to replace the complex architecture and functions of a fully mature organ. Still, the field of stem cells and regenerative medicine has seen significant progress in clinical applications and with more research, the possibility of organs generated from stem cells is within reach. Stem cells and their unique, versatile qualities offer many solutions to future medicine.