Stem cells and stem cell therapy have received a lot of news coverage lately, some of it controversial, so this month I’ve decided to discuss stem cells in general, along with several approaches to stem cell therapy. The stem cell therapies I advocate are both legal and simple, especially with the advent of a new nutritional product called Stemplex, which I’ll discuss a little later. But first, a little about the stem cell itself…
Embryonic Versus Adult Stem Cells
A stem cell is an undifferentiated cell that can renew itself and develop into at least three different types of tissue. Embryonic stem cells are derived from early stage embryos and have the ability to differentiate into all adult cell types. Embryonic stem cells behave in a consistent way under a microscope but are much less predictable when injected into the body. They can offer some benefits for research but their use is controversial and they are not useful for actual treatments.
Adult stem cells reside in post-fetal animals. Examples are linage-committed such as hematopoietic stem cells that become red or white blood cells, or mesenchymal stem cells that can become many types of tissue, including bone, tendon, ligament, cartilage, heart, liver, or nerves. Sources of adult stem cells include bone marrow, fat, brain tissue, and muscles. Of all the tissues, fat yields the largest numbers of mesenchymal stem cells, while bone marrow or umbilical blood yield more stem cells that will become red or white blood cells.
Types of Stem Cells
There are several different categories of stem cells, including autologous, allogenic, and xenogenic. Autologous stem cells are those derived from the same animal. These are best for transplanting since there is no concern about them being rejected. Allogenic stem cells are from a donor of the same species. Since stem cells do not have the standard cell surface markers that would trigger immune response, these cells can potentially be used without fear of rejection by the host tissue. Xenogenic stem cells come from a donor of another species, such as a pig. Although one would expect these cells to be rejected, because of their unique characteristics they can survive, in some cases, when injected into the body of another species.
How Do Stem Cells Work?
The most commonly cited function of stem cells is their ability to differentiate into different tissues but they also have other abilities that can be very beneficial for healing. Stem cells produce over 30 types of growth factors and tissue chemicals that stimulate healing. Stem cells help recruit other local and systemic stem cells to focus on repairing damaged tissue. They are also active in immune modulation to promote or suppress T-cell function.
Stem cells are triggered to move into an area by signals from the tissue based on chemical, neural, and mechanical changes. Hypoxia, which is lack of oxygen, and inflammation are strong triggers for stem cells to target an injury, although the stems cells account for less than half of the new tissue formed. The rest of the repair is done by other cells recruited and managed by the initial stem cells. This is why very tiny injections of stem cells are used. Injecting larger numbers of stem cells into an injured area can actually interfere with healing, since some of the injected cells die and must be removed during the healing process.
Under ideal conditions stem cells would respond to injuries and healing would occur. Factors that affect stem cell response include the age of the animal, the fitness of the animal, and the level of free radicals in the body. Free radicals damage all cells, including stem cells.