Peter Fernández, Marie‐Thérèse Linossier, Marie Pierre Bareille, Rebecca Billette de Villemeur, Ines Antunes, Angelique Van Ombergen, Nastassia Navasiolava, Marc-Antoine Custaud, Maura Strigini, Laurence Vico
Dry immersion induces rapid bone deconditioning in both sexes, but females show greater skeletal sensitivity to unloading, with stronger resorptive increases [tartrate-resistant acid phosphatase isoform 5b (TRAP5b), crosslinked C-terminal telopeptide of type I collagen (CTX)] and a more pronounced periosteal decline (periostin) that does not recover after immersion. Concurrent rises in IGF-1 and visfatin are suggestive of coordinated metabolic-skeletal responses. These sex-specific biomarker patterns highlight early physiological differences and may help guide the development of targeted countermeasures for spaceflight and immobilization.