Wound Healing Capacity of Adult Human Fibroblasts Derived from the AGBRESA Bed Rest and Artificial Gravity Study Subjects

Kurzfassung

During spaceflight, the microgravity-environment induces physiological adaptations in the human body. Of particular interest for this thesis was the impairment of the wound healing process during long-term exposure to weightlessness. The underlying molecular and cellular mechanisms of wound healing alterations in skin tissue in microgravity are unknown. However, with attenuated wound healing, the chance for infections increases, possibly threatening missions in space and the health of astronauts. A well-established model to mimic physiological deconditioning in response to weightlessness is HeadDown Tilt (HDT) bed rest on Earth. HDT bed rest was evaluated as a model system for wound healing. Further, 30 minutes of Artificial Gravity (AG) were applied daily as a potential countermeasure either continuously (cAG) or in 5 minute intervals (iAG). During the Artificial Gravity Bed Rest Study with European Space Agency (AGBRESA), a new method to isolate primary adult human fibroblasts from skin biopsy tissue has been established to evaluate wound healing in bed rest subjects. A prolonged closure time in the scratch assays for cAG and bed rest group was indicated, while this trend was alleviated for iAG. Thermography was a well tolerated method for monitoring of the biopsy site and revealed a significantly increasing wound temperature in both AG groups over the course of the HDT phase. Analysis of the blood serum-based inflammation markers CRP, IL-6 and leukocytes ensured that no infections, inducing a deteriorated healing process, were occurring. Investigating the effects of AG in HDT bed rest subjects, it was found that AG is able to change the effects of bed rest on humans and thus might result in possible positive effects on the impaired wound healing process in weightlessness. In general, HDT bed rest induces changes in wound healing that still remain to be evaluated, especially regarding their comparability to spaceflight-induced alterations in wound healing.