Donor age and sex program MSC secretome signaling: a quadrant framework for precision therapy

A signaling-centered, donor-stratified framework may help organize heterogeneous findings in the MSC field and generate testable predictions for potency assessment, indication matching, and study design. Because most available evidence evaluates sex or maturity in isolation and under diverse tissue sources and manufacturing conditions, the proposed quadrant model should be interpreted as hypothesis-generating. Prospective, harmonized, head-to-head validation across donor quadrants will be required to determine its translational utility.