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.
Stem Cell Therapy for Knees in Horses
In horses the repair of ligament injuries has shown the most promise. Injuries to the ligaments in a horse’s lower leg are notoriously difficult to heal. Stem cells harvested from the injured horse’s own fat can be injected directly into the area of ligament damage to stimulate healing with less scarring, which decreases the chance of re-injury. In some cases bone marrow is harvested, but this tissue must be cultured to increase the numbers of mesenchymal stem cells.
Another promising Stem Cell Therapy for Knees is based on increasing the numbers and activity of the animal’s own stem cells using nutrition. Just as scientists discovered that beta glucan is a nutrient that stimulates the white blood cells called macrophages, researchers have now identified nutrients that stimulate and cause the proliferation of stem cells. Based on this research, Simplexity Health has developed a product called Stemplex (TM) that contains green tea extract, wild blueberry, the amino acid carnosine, blueberry extract, vitamin D, and blue-green algae. I have been using this product on my own horse, who has chronically contracted and sore heels. Within just a month I am seeing improvement in his gait.
Stem Cell Therapy for Knees has huge potential and should be considered as a healing treatment for injuries or organ damage. In addition, systemic stem cell therapy shows promise in treating neurological conditions. Providing nutritional support for the body’s own stem cells is always a good option, which can be supplemented by using targeted injections of harvested stem cells. These injections are especially useful when nutritional support does not create enough healing effect or the injured area, such as ligaments in a horse’s lower leg, has poor circulation.