P60 | UNDERSTANDING HUMAN INTERVERTEBRAL DISC HOMEOSTASIS: 3D EXPERIMENTAL MODELS

L. Penolazzi¹, A. Chierici¹, R. Nadalini¹, E. Lambertini², C. Nastruzzi³, G. Lisignoli⁴, C. Manferdini⁴, G. D’Atri⁴, R. Piva¹ | ¹Department of Neurosciences and rehabilitation, University of Ferrara, Italy; ²Laboratorio centralizzato di ricerca preclinica, University of Ferrara, Italy; ³Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Italy; ⁴Laboratorio di Immunoreumatologia e Rigenerazione Tissutale, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy

In recent years, there has been an increasing focus on the creation of in vitro experimental models that, by mimicking the physiopathological conditions of a given tissue, allow to obtain increasingly informative data, overcoming the use of often inadequate animal models. This is the case of the human musculoskeletal system, which, with regard to the anatomical and biomechanical properties associated with posture, cannot be faithfully replicated in animals. The attempt to create a model that mimics the human intervertebral disc (IVD) led us to develop the models reported below mainly to satisfy two reasons. The first concerns the creation of a cellular platform useful for studying the mechanisms underlying the maintenance of IVD homeostasis and the cellular response to physical/chemical treatments. The second concerns the creation of tissue-engineered constructs that can be implanted or injected into the site of damage, where the IVD has undergone degeneration/inflammation. Physiologically, IVD cells reside in hypoxic condition, devoid of vascularization and constantly exposed to mechanical stress (compression, tension and shear) which regulate their metabolism. IVD cells can degenerate due to aging, obesity, environment and genetics and cause neck and lower back pain, which are a major cause of disabling diseases. We have developed 3D systems based on multifunctional hydrogels (WJMs, 3D millicylinders), composed of various percentages of alginate, gelatin, and human decellularized Wharton’s jelly (DWJ) that together constitute an optimal scaffold for IVD cells from biopsies of IDD patients undergoing discectomy¹. We have demonstrated that WJMs are particularly effective in: a) supporting the viability and functional recovery of degenerated cells that resume their healthy chondrogenic-like phenotype (expressing SOX9, Integrin β1, Brachyury previously recognized as critical regulators of IVD homeostasis), thanks to the anabolic factors present in the DWJ; b) transmitting mechanical load to the cells and resisting permanent deformation when subjected to FlexCell FX-4000C pressure apparatus.