When we get injured, our bodies know best of how to fix itself. That being said, injuries sometimes need a small nudge in the right direction to heal appropriately. There are many different injuries from a torn rotator cuff, exercise induced injuries to paresthesia and spasticity from a stroke. While the cause of the injury can differ dramatically from person to person, the bodies reaction remains constant. Any penetrating injury or hypoxic insult causes damage to the underlying tissue which causes the release of cytokines into the blood and surrounding tissues.
These cytokines cause a reaction to occur that starts with white blood cells and platelets. The platelets have receptors on them call integrins that detects an injury and causes the platelets to hon into the area of damage. White blood cells and platelets come to the area as well to prevent any foreign material or bacteria from entering the bloodstream, and clot any active bleeding along with secreting Interleukin (IL-1, IL-6, IL-8) and Insulin Growth Factor (IGF–1).
The effects of these cytokines are recruitment of satellite and progenitor cells which start the rebuilding process. Once the stromal component are damaged, the cells go to work to rebuild and regenerate the area. With injury, transforming growth factor (TGF)-B1 stimulates myogenic cells and muscle-derived stem cells to differentiate into myofibroblast which synthesize a type of collagen that leads to fibrosis.
While fibrosis helps to strengthen the integrity of the tissue injured, it can also cause limitations such as contractions or spasticity not to mention the skin puckering visual effect of a scar. In some cases during tissue injury, our body does not mount the required response to adequately address all the components and we are left with chronic pain or paresthesia. Most of us throughout our lives will have some kind of chronic pain. Whether it is tennis elbow, lifting joint injuries, muscle tear, stroke or something more insidious such as certain daily repetitive movements, the best way to correct the problem without having a “band aid” that will have to be repeated often is through our stem cells which ultimately are responsible for correcting the damage innately. One of the way stem cells know where to go and what to do is through cytokines and growth factors. These are chemicals and proteins that get released either from direct damage to a cell causing the cells contents to leak into the surrounding tissue or through a certain stimulation of a cell causing it’s granules holding the cytokines to release their package. Platelets role in wound healing now becomes very important due to the amount, and types of growth factors in their cytoplasmic granules.