Most people have heard of stem cells and stem cell research and are aware of the controversy that surrounds this practice but the average layperson probably doesn’t completely understand what this subject is all about.
A stem cell is, basically, a clear cell that has the ability to become another different cell type in the human body, including a muscle cell, a nerve cell or a skin cell.
Stem cells are used to heal damaged cells in the body and heal or replaced damaged tissues. Stem cells are essentially an en suite repair method for the human body because they reload other cells as long as a person is alive.
When a stem cell divides, each ‘daughter’ cell has the capacity to become either a different kind of cell with a dedicated function, such as becoming a red blood cell, or the ‘daughter’ can remain a stem cell.
A stem cell that can only give rise to a small number of various cell types is called multipotent, while the stem cells that can give rise to virtually any type of cell, except those cells that are required to support and develop a fetus in the womb, are called pluripotent stem cells.
Pluripotent stem cells can be taken from human embryos that are a couple of days old. These embryo cells are used to make cell cultures that are capable of growth for the unforeseen future in a lab setting and which create pluripotent stem cell lines. This type of stem cell line has also been created using fetal tissue that is older than eight weeks in development. The reason human embryonic stem cells are preferred over adult stem cells is their greater development aptitude. However, scientists have devised a way to use particular adult human cells that are capable of genetic reprogramming so that they take on a stem cell-like state. These precise stem cells are called induced pluripotent stem cells or (iPSCs).
The glory of stem cell lines is that they are basically everlasting regardless of how the stem cell line was established from a cell in the body. These stem cell lines grow forever. The cells can be frozen or distributed to researchers.
In the future scientists hope that they are capable of replacing a person’s injured genes or introduce new genes to stem cells, which would give the cells the attributes it needs to treat diseases.
Many question the ethics of stem cell research because up until recently the only way a pluripotent stem cell could be accessed was by taking it from the inner cell mass of an embryo and putting it in a lab dish. Many think it is unethical to destroy a human embryo even if the embryo is only a couple of days old. Now that iPSCs (from adults) are available the argument is becoming less important even though iPSCs are not identical to the stem cells taken from an embryo.
In the United States, it is against the law to create an embryo for research reasons. Instead, scientists used ‘leftover’ embryos that originate in fertility clinics with the express permission of the donors. These ‘leftover’ or spare embryos were created during the process of infertility treatment but were not implanted in a woman and were set to be discarded.
Fetal stem cells can be taken from aborted fetuses as well as from umbilical cords. The cord blood contains stem cells that are very much like the cells found in bone marrow.
Stem cells are in a placenta. In fact, ten times more stem cells can be harvested from a placenta as would be harvested from cord blood.
About the Author: Aurora May writes for Family Cord, a cord blood bank storage and donation center.
Image credits: adapted from Wikimedia Commons