Oral Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

The potential of nasal chondrocyte spheroids for intervertebral disc repair (#MP-13e)

Raphael Schmid 1 2 , Janhavi Apte 2 , Andrea Barbero 2 , Ivan Martin 2 , Stefan Schären 1 , Karoliina Pelttari 2 , Olga Krupkova 1 2 , Arne Mehrkens 1
  1. Spine Surgery, University Hospital Basel, Basel, Switzerland
  2. Department of Biomedicine, University of Basel & University Hospital Basel, Basel, Switzerland

Introduction: Painful degenerative disc disease (DDD) is a prevalent condition associated with catabolic shift, inflammation, and extracellular matrix (ECM) degradation in the intervertebral disc (IVD). Existing treatments are inadequate in arresting DDD, highlighting the need for innovative approaches that can withstand the harsh microenvironment in degenerated IVD. Nasal chondrocytes (NC) were shown to adapt to heterotopic transplantation sites and form ECM in damaged/degenerated cartilage. We thus aim to explore the potential of NC-derived 3D spheroids (NCS) for cell-based nucleus pulposus (NP) repair.

Methods: Whole bovine caudal IVDs cultured ex vivo underwent combined treatment of Chondroitinase ABC, low-grade pro-inflammatory cytokines, and dynamic compression, to mimic early-stage DDD. NCS were generated from mCherry transduced NC, chemically and/or metabolically pre-conditioned to withstand DDD microenvironment, and injected by spinal needle into the ex vivo DDD model. NCS ability to survive, engraft, and function in harsh DDD microenvironment in vitro and ex vivo was evaluated by RTqPCR, ELISA, histology, and immunostaining.

Results: Early-stage DDD was accurately recapitulated in bovine IVD ex vivo after 7 days, with induced catabolism (MMP13), inflammation (IL-8 release), ECM degradation (SafO), and consequent water loss (MRI). Pre-conditioning of NCS with hypoxia, low glucose, and IL-1Ra significantly enhanced their viability and ECM formation (SafO) and notably reduced inflammation (IL-8 release), catabolism (MMP13), and senescence (p16) markers in a simulated DDD environment in vitro, compared to NCS cultured in standard conditions. In the ex vivo DDD model, pre-conditioned NCS mostly survived and started separating and engrafting into NP tissue 4 days after injection, leading to different cell populations (apoptotic/non-apoptotic) with potentially distinct effects on NP repair.

Discussion: We developed a new early-stage DDD ex-vivo model and demonstrated its suitability for cell therapy screening studies. We have also shown that depriving NCS of glucose and oxygen and pre-treatment with IL1-Ra leads to higher matrix formation, better cell viability, significantly better resistance to inflammation, and engraftment in degenerated native IVD. NCS are now being tested in a large animal model and manufactured according to GMP guidelines to create NCS product suitable for human use. The molecular mechanisms of NCS resistance and function in native IVD are being analyzed.

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