DECELLULARIZED WHARTON’S JELLY MATRIX - BASED SCAFFOLD FOR HUMAN DEGENERATED INTERVERTEBRAL DISC CELLS

Regenerative therapies for intervertebral disc (IVD) injuries are currently a major challenge that is addressed in different ways by scientists working in this field. Tissue engineering approach may rely on extracellular matrix (ECM) from decellularized perinatal tissues that has been established as a biomaterial with remarkable regenerative capacity.  OBJECTIVE: primary aims were: 1. setting up an in vitro experimental model similar to the one that IVD cells experience in vivo, and 2. investigating the behavior of degenerated/de-differentiated IVD cells when exposed to hypoxic preconditioning and combined with decellularized Wharton’s jelly matrix (DWJM) from human umbilical cord. MATERIALS AND METHODS: an efficient detergent-enzymatic treatment was used to produce DWJM maintaining its native microarchitecture. IVD cells were obtained from surgical hernia biopsies after informed consent. X3 Hypoxia Hood and Culture Combo - Xvivo System device was used for hypoxia condition (2% pO 2 ). Biochemical assays, electron microscopy and immunofluorescence analysis were used to characterize the properties of DWJM and expression of specific markers. RESULTS: when combined with IVD cells, DWJM was able to produce sizeable 3D cell aggregates and restore the native chondrocyte-like phenotype of the IVD cells. 3D cell aggregates were able to respond to hypoxia, become HIF-1α positive and, in addition to further increasing the expression of two typical pro-chondrogenic transcription factors, SOX-9 and TRPS1, expressed high levels of FOXO3a, a core regulator of cellular homeostasis, stress response, and longevity. CONCLUSIONS: for the first time, we demonstrated the efficacy of hypoxia preconditioning of human IVD cells combined with an ECM-based scaffold to improve the IVD degenerated phenotype. Our data are in line with the hypothesis that the strengthening of cell properties in terms of viability and expression of specific proteins at precise times represents an important condition in the perspective of guiding the recovery of cellular functionality and triggering the endogenous regenerative potential. Currently, there are no definitive surgical or pharmacological treatments for IVD degeneration able to restore the disc structure and function. Thus, the efficacy of hypoxia preconditioned cells combined with DWJM in promoting cell differentiation towards a discogenic phenotype paves the way in the near future for innovative ECM-based intradiscal injectable therapies.