One solution is to use allogeneic cells from a therapeutically potent donor, but even optimal cells may not provide benefit if the recipient’s regenerative capacity is poor. It was suggested that although the focus in stem cells trials is typically on the administered  cells, there is little on the patient and tissue targeted for regeneration. Indeed, there is evidence that the variable cell potency observed across patients in clinical trials reflects not just the quality of delivered cells but also the underlying regenerative capacity of the treated patient. With the growing understanding that stem cell therapy functions to a large extent via paracrine  mechanisms, it seems clear that the recipient’s regenerative capacity is likely a critical determinant of therapeutic effect.