Understanding and shaping of bone regeneration by cellular metabolic adaption will be targeted by Sawitzki and Duda. Preliminary date revealed differences in metabolism between successful healing in young and impaired fracture healing in aged individuals. Biosynthetic intermediates from the glycolysis and the TCA cycle showed a faster and stronger increase in young animals. Also, metabolites such as lactate and succinate can act as signalling molecules influencing immune cell functionality as well as bone matrix formation. Sawitzki and Duda want to reveal which cell populations undergo metabolic reprogramming, which local signals and inter-cellular communication pathways control this reprogramming, whether the metabolic differences contribute to successful versus delayed healing and whether and how cellular metabolism could be modified to support bone regeneration processes. A fine-tuned communication between cells (e.g. immune cells, fibroblasts) in the early, metabolically challenging phase of healing is central to metabolic adaptations and thus successful cellular self-organisation in early callus formation.