Stem Cells Engineered for Tendon Repair

A recent report described a method for transforming mesenchymal stem cells (MSCs) into tendon-like cells (tenocytes), which may lead to an advance in the treatment of injuries to tendons or ligaments.

Investigators at the Hebrew University of Jerusalem (Israel) implanted the gene for a biologically active variant of the Smad8 growth factor into an MSC line that co-expressed the osteogenic gene bone morphogenetic protein 2 (BMP2). SMAD8 is a member of the MAD-related family of molecules. MAD-related proteins are a recently identified family of intracellular proteins that are thought to be essential components in the signaling pathways of the serine/threonine kinase receptors of the transforming growth factor beta super family. Bone morphogenetic proteins (BMPs) are growth factors belonging to the TGF-beta (transforming growth factor-beta) super family with a strong ability to induce new bone and/or cartilage formation.

The genetically engineered MSCs were implanted into rats with torn Achilles tendons. Results published in the April 2006 issue of the Journal of Clinical Investigation revealed that in their new environment the MRCs transformed into tenocytes capable of inducing tendon regeneration. This transformation was demonstrated by double quantum-filtered magnetic resonance imaging (MRI).

The authors concluded, "These findings may have considerable importance for the therapeutic replacement of tendons or ligaments and for engineering other tissues in which BMP plays a pivotal developmental role.”



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Hebrew University of Jerusalem