On Wednesday the 11th of September Johannes Lehmann (postdoc de Keizer lab) will defend his PhD thesis: ‘ The Age of Rebuilt Cartilage' at the Queridozaal at the Erasmus MC, Rotterdam. During his PhD, Johannes investigated how WNT signalling inhibits paracrine senescence in mesenchymal stem cells as well as how cartilage defects can be repaired with the extracellular matrix of ear cartilage. His promotor is Prof. Gerjo van Osch, his copromotor Dr. Derk ten Berge.