The aim of the joint Interreg project FIT (Fitness Improving Technology) is to introduce a novel stem cell therapy for patients with muscular dystrophies. The project is financed by the European Union and co-financed by North Rhine-Westphalia (NRW) and the relevant local provinces in the Netherlands and Belgium. The therapy uses the patient's own muscle stem cells and is close to being able to effectively treat patients. A key achievement of the previous Interreg GYM (Generate Your Muscle) project was being the first in the clinic to test this therapy. Building on this, the academic-private partnership of the FIT project, comprising the universities of Maastricht, Leuven, Liège, Hasselt and Aachen, as well as the SMEs Milocron, Scinus, Revatis, BamVerbrugge and ReWrite), will develop optimized muscle stem cell technology. This technology will be used to treat various conditions, including rare genetic muscle diseases, the common age- or cancer-related loss of muscle mass, sports injuries and heart muscle conditions.

In our subproject, we will contribute to FIT's objectives with a novel 3D in vitro tissue model. The basis of this model was developed in our lab as part of the previous GYM Interreg project. In FIT, we will further improve the biological performance of the model anduse it  to investigate  the complex mechanism of transendothelial migration in vitro , which is not yet fully understood. This is important because a fundamental problem with systemic stem cell therapies is their low efficiency. In most cases, only a small proportion of the injected stem cells reach the diseased muscle. Improving our understanding of how transendothelial migration can be enhanced could therefore increase the efficiency of stem cell therapy in clinical applications (Fig. 1).