RESEARCHERS ISOLATE CHEMICAL SIGNAL THAT CAUSES STEM CELLS TO REPAIR SKIN:

Bone marrow has long been thought to have a role in repairing damaged skin, and now UK and Japanese researchers think they’ve found the key to summoning stem cells from bone marrow to the site of damaged skin: a signal known as HMGB1. By tapping this signaling mechanism, researchers could develop new treatments for skin injuries like severe burns. HMGB1 sends out a distress call when stem cells are needed. However, it is only sent out when it is initiated by certain conditions.  "Researchers injected some trackable fluorescing bone marrow cells into mice so they could track their movement. They then looked at the way the stem cells reacted to certain stimuli. In mice with mere flesh wounds, few marrow stem cells flocked to the injury site. In mice given skin grafts, many stem cells made their ways to the wound to help repair the damaged skin."  Skin grafts have no blood vessels or oxygen in them, and for whatever reason this environment leads to the release of HMGB1, which appears to be the direct signal that the stem cells respond to.