Annulus fibrosus repair

AO Spine
Z Li, S Grad


Appropriate cell sources, bioactive factors and biomaterials for generation of functional and integrated annulus fibrosus (AF) tissue analogues are still an unmet need.



To induce a functional cell population from AF cells for enhanced AF extracellular matrix (ECM) synthesis and repair.



Supplementation of TGF-β1 upregulated gene and protein expression of several AF cell markers in human mildly degenerated AF cells and increased cell contractility, indicating that TGF-β1-pre-treated AF cells may be an appropriate cell source for AF tissue engineering or AF rupture repair. Collagen type I hydrogel as a cell carrier maintained the phenotype of human AF cells. TGF-β1 treatment within the collagen hydrogel further promoted cell proliferation and matrix production of AF cells both in vitro and ex vivo. In a bovine intervertebral disc organ culture model, TGF-β1 containing collagen type I hydrogel-polyurethane scaffold hybrid system retained the AF phenotype of implanted cells. These constructs have potential for generating tissue engineered AF and warrant further investigation for their use in repairing AF defects after discectomy.

  • Publications

    Long RG, Ferguson SJ, Benneker LM, Sakai D, Li Z, Pandit A, Grijpma DW, Eglin D, Zeiter S, Schmid T, Eberli U, Nehrbass D, Di Pauli von Treuheim T, Alini M, Iatridis JC, Grad S. Morphological and Biomechanical Effects of Annulus Fibrosus Injury and Repair in an Ovine Cervical Model. JOR Spine 2019, e1074.

  • Presentations

    Du J, Long RG, Sakai D, Benneker LM, Iatridis JC, Alini M, Grad S, Li Z. Cell seeded collagen-polyurethane scaffold supplemented with TGFβ for annulus fibrosus repair. 2019 TERMIS EU (oral)

    Li Z. Annulus fibrosus repair with endogenous cell activation and function inducing cell transplantation. 2019 ICORS (oral)

    Li Z, Du J, Long RG, Sakai D, Benneker LM, Iatridis JC, Alini M, Grad S. Functional cell phenotype induction with TGFβ1 and collagen-polyurethane scaffold for annulus fibrosus repair. 2019 ORS PSRS (poster)

  • Partners

    Sakai D (Prof), Tokai University School of Medicine, Isehara, Japan

    Benneker LM, (Prof), Inselspital, University of Bern, Bern, Switzerland

    Iatridis JC (Prof), Icahn School of Medicine at Mount Sinai, New York, NY 

    Pandit A (Prof), CURAM, National University of Ireland, Galway, IRL