The regenerative capacities of mesenchymal stem cells (MSCs) are multifaceted, and the insights into their trophic mechanisms in context of tendon therapies are scarce. In vitro models serve as important biological tools to study cell behavior under specific, controlled, and reproducible conditions. Unfortunately, no generally accepted in vitro model exists to date. In the current PhD project, additive manufacturing will be applied in which cells and biomaterials will be combined in order to develop a physiologically representative in vitro tendon injury model. As biomaterial, gelatin, isolated from collagen, the most abundant protein in tendon, will be applied. The 3D-printed gelatin constructs, composed of a shell containing equine tenocytes and an angiogenic core containing equine endothelial cells, will be cultured and subjected to mechanical stimulation. Next, metabolites and their pathways involved in tendon (patho-)physiology will be identified using metabolomics/lipidomics. The regenerative effect of the MSC secretome in the tendon injury model will be verified by evaluating the identified pathways. Different MSC sources will be evaluated to identify the most appropriate MSC source to treat tendon injuries. The insights acquired in this research project will initiate the development of targeted tendon injury therapies, based on metabolic pathway identification, which will be beneficial for both equine veterinary and human medicine.