For back disorders, cell therapy is one approach for a real regeneration of a
degenerated nucleus pulposus. Human mesenchymal stem cells (hMSC) could be
differentiated into nucleus pulposus (NP)-like cells and used for cell therapy. Therefore it
is necessary to find a suitable biocompatible matrix, which supports differentiation. It
could be shown that a differentiation of hMSC in a microbial transglutaminase cross-linked
gelatin matrix is possible, but resulted in a more chondrocyte-like cell type. The addition of
porcine NP extract to the gelatin matrix caused a differentiation closer to the desired NP
cell phenotype. This concludes that a hydrogel containing NP extract without any other
supplements could be suitable for differentiation of hMSCs into NP cells. The NP extract
itself can be cross-linked by transglutaminase to build a hydrogel free of NP atypical
substrates. As shown by side-specific biotinylation, the NP extract contains molecules with
free glutamine and lysine residues available for the transglutaminase.