Microgravity in Space and its Effect on Wound Healing

Abstract

Wound healing in microgravity conditions presents with conflicting results despite the signals coming from individual cells which indicate otherwise. Isolated skin cells cultured in microgravity simulations show enhanced stem cell activity and increased migratory behavior, but real animal tissue and real spaceflight data refute it consistently showing delayed wound healing, slow blood vessel growth and slower fibroblast movement. This discrepancy between in-vivo and In-vitro findings is the general pattern across the research and this pattern flows to collagen biology as well, cells appear more active under microgravity but fail to rebuild overall tissue structure. A specific molecular pathway that includes Fibrous-actin (F-actin) and Yes-Associated Protein (YAP) signaling which have been identified as one of the drivers of the impairment in fibroblasts and a countermeasure drug known as Lysophosphatidic Acid (LPA) has already been tested successfully in an animal model. Real human data, including a documented postflight skin rash case and cytokine changes from the NASA Twins Study, confirm the visible signs of changes taking place at the cellular level even after the flight in human beings. The current gap in this field is detected to be the limited human data on wound healing collected in actual flight conditions. The majority of the findings still come from cell culture or animal models and a major gap remains, as no controlled study has yet directly tracked wound healing in-vivo in humans during spaceflight aboard the International Space Station (ISS).