Current Research on Stem Cells
The primary question of developmental biology is how do multicellular organisms form
from a single cell? An important part of the answer of that question is stem cells. A stem cell is
defined as a cell in the body that can differentiate into other type of cells. Stem cells have the
capability to produce two cells of different fate upon division: one cell remains a stem cell and
the other cell intended to differentiate. (Yan). There are many different types of stem cells that
arise at different stages of development. Embryonic stem cells form in the early stages of
embryonic development, in which they remain undifferentiated and possess the ability to become
almost any tissue within the body. There has and continues to be much debate within the public,
politicians, scientists and religious organizations on the use of embryonic stem cells in research
and treatment. The embryo is effectively destroyed after the stem cells are extracted and many
see this as the equivalent of taking a life. This debate put a hold on some aspects of research, but
the discovery of adult stem cells found a balance between those for and against the use of
embryonic stem cells. Adult stem cells, or somatic stem cells, are most widely used in research
and therapy, and are also multipotent—give rise to a specific tissue or organ. Fetal stem cells are
cells with the fetus that are pluripotent and eventually develop into the different body tissues.
Umbilical cord stem cells are contained in the blood from the umbilical cord of a newborn and
are multipotent. Peripheral blood stem cells are found in the blood stream and give rise to red
blood cells, platelets, granulocytes, and lymphocytes. There are induced pluripotent stem cells
(iPSCs), which are adult cells that have been genetically changed to mimic embryonic stem cells.
( Marlicz). Recently, there has been the discovery of cancer stem cells creating tumors that
maintain themselves (Clevers).
Stem cells represent an exciting area of study because of their potential to regenerate and
repair damaged tissue. This also makes them a very important and common topic of research in
biology. Many studies have been done to find ways to actively use stem cells in treatment of
tissue damage. Some current therapies, such as bone marrow transplantation, already make use
of stem cells and their potential for regeneration of damaged tissues. Other therapies are under
investigation that involves transplanting stem cells into a damaged body part and directing them
to grow and differentiate into healthy tissue. Many researchers have been struggling to maintain
survival of these cells for transplantation purposes. Mesenchymal stem cell therapy is used to
treat multiple disorders. The death of most cells after transplantation caused by several factors
such as mechanical damage, free radicals, lack of growth factors, and time length passed after
isolation from the body is the most challenging issue in therapeutic use of stem cells. Many
researchers have been struggling to maintain survival of these cells for transplantation purposes.
A thorough understanding of stem cells is necessary to learn more about early human
development, how birth defects occur and how they can be prevented or possibly reversed, and
in the use of cell therapies. Current studies into stem cell research are making strides into
developing methods and technology that make stem cells a common part of cell therapy. (Over
Expression)
Stem cells in cardiac tissue
An important aspect of stem cell research is the identification of stem and progenitor cells
within adult tissue, much of which has no potential to differentiate. For example, for many years
it was believed that tissues of the mammalian heart were not able to regenerate, making any
damage to the tissue difficult to repair. When cardiac stem cells are injected into a heart, these
cells reconstruct well-differentiated myocardium, formed by new blood vessels and myocytes
(Timmers). The adult heart, like the brain, is mainly made of terminally differentiated cells, but is
not a terminally differentiated organ because it contains stem cells supporting its regeneration
(Beltrami). The existence of these cells opens new opportunities for myocardial repair. Recent
study found that the mammalian heart does contain progenitors, and being able to identify these
primitive cells on a molecular level made it possible to discover cells in within the myocardium
that can be used in cardiac tissue repair. Additionally in past studies, tissues have been shown to
have stem cells and progenitors that repopulate parts of other tissue, i.e. hematopoietic
progenitors, skeletal myoblasts, and bone marrow derived mesenchymal stem cells can
repopulate damaged cardiac tissue. (Dey)
The Stanford University School of Medicine has conducted research that will make great
strides in the understanding how of stem cells can be used in cardiac tissue repair. Their research
