jsc2025e065389 (6/26/2025) --- Bone-forming or mesenchymal stem cells from human bone marrow stained with red dye. An investigation on the International Space Station, Microgravity Associated Bone Loss-B (MABL-B), assesses how these cells respond to microgravity, including changes in gene expression and the secretion of signaling proteins that promote bone formation and increase bone loss. Results could provide insight into bone loss that occurs during spaceflight and from normal aging and disease on Earth. Credit: Mayo Clinic