SOD1 and diabetes mellitus: Single-protein testing identified CALU and SOD1 as leading candidates, improving glucose tolerance and reducing nonfasting glucose.<h4>Conclusion</h4>This study defines a set of MSC-secreted proteins that promote islet regeneration in vivo, supporting the development of protein-based biologics to preserve or restore beta cell function during diabetes, with potential applications alongside islet replacement therapies to enhance graft survival and function.