Adult Stem Cells serve as an internal repair system, dividing essentially without limit, to help nourish other cells and develop new cells. Stem cells are present in blood, bone marrow, and adipose tissue (fat) and their primary purpose is maintenance. Adult stem cells are generally multipotent, which means they are able to give rise to several kinds of cells found in body tissues. One can think of adult stem cells as the built-in repair kits, regenerating cells damaged by disease, injury and everyday wear and tear. These undifferentiated cells reside among other differentiated cells found in tissues or organs and when they divide, they become specialized to repair or replace the surrounding differentiated cells.
Bone marrow contains two types of stem cells: hematopoietic cells and stromal cells.
Hematopoietic stem cells give rise to the three classes of blood cells that are found in the circulation: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes). The most common type is the hematopoietic stem cell (HSC-CD 34+). Most of the current literature suggests that these cells are the ones responsible for tissue regeneration and luckily, these cells do not diminish in number as we age.
Mesenchymal stem cells, also known as marrow stromal cells, lie in the central sinus of the bone. These cells have the capacity to form various cells of the body including osteoblasts (that form bones), chondrocytes (that form cartilage), myocytes (that form muscles), and other cells. Many stem cell research theories suggest that these cells are more important for preparing the microenvironment around the cells so that the hematopoietic cells are more receptive to do their work. Unfortunately, as we age the number of mesenchymal stem cells in the bone marrow diminishes. Apart from this there are the endothelial stem cells that form blood vessels.
Fat is one of the richest sources of stem cells in the body, especially in terms of the concentration of mesenchymal stem cells. The number of mesenchymal stem cells in fat far exceeds the numbers found in a similar amount of bone marrow tissue.
Once regenerative cells are reintroduced to the injured area, the platelets then release signal proteins and growth factors that stimulate stem cells. These signal proteins and growth factors are called cytokines. It is important to understand that stem cells by themselves are unable to repair the injured area; stem cells must be properly directed, cytokines perform the repair function. Platelets are made in the bone marrow; hence, they are really important in guiding the stem cells to the injured area.
In effect, stem cells are like seeds and the platelets are their fertilizers. Once they are activated, stem cells perform a variety of valuable functions. Apart from repairing damage to the injured areas, stem cells help the damaged and weak cells in our bodies to restore themselves and aid in the body’s natural repair processes.
Generally, the total repair process takes two to three months to complete but in most cases, improvement can be noticed before then. Optimal results are seen as stem cells to continue to differentiate and grow new tissue.
There are various conditions that can affect the progress of stem cell therapy, some positively, others negatively. Patients undergoing stem cell therapy or platelet-rich plasma treatments are advised to minimize their intake of alcohol, as consumption tends to delay the body’s ability to release stem cells. Some supplements have been found to increase the number of stem cells; these include carnosine, blueberry extract, vitamin D3, and green tea extract.