Decellularized matrix for repairing intervertebral disc degeneration: Fabrication methods, applications and animal models

Abstract

Intervertebral disc degeneration (IDD)-induced low back pain significantly influences the quality of life, placing a burden on public health systems worldwide. Currently available therapeutic strategies, such as conservative or operative treatment, cannot effectively restore intervertebral disc (IVD) function. Decellularized matrix (DCM) is a tissue-engineered biomaterial fabricated using physical, chemical, and enzymatic technologies to eliminate cells and antigens. By contrast, the extracellular matrix (ECM), including collagen and glycosaminoglycans, which are well retained, have been extensively studied in IVD regeneration. DCM inherits the native architecture and specific-differentiation induction ability of IVD and has demonstrated effectiveness in IVD regeneration in vitro and in vivo. Moreover, significant improvements have been achieved in the preparation process, mechanistic insights, and application of DCM for IDD repair. Herein, we comprehensively summarize and provide an overview of the roles and applications of DCM for IDD repair based on the existing evidence to shed a novel light on the clinical treatment of IDD.

Keywords: (3D), three-dimensional; (AF), annular fibers; (AFSC), AF stem cells; (APNP), acellular hydrogel descendent from porcine NP; (DAF-G), decellularized AF hydrogel; (DAPI), 4,6-diamidino-2-phenylindole; (DCM), decellularized matrix; (DET), detergent-enzymatic treatment; (DWJM), Wharton's jelly matrix; (ECM), extracellular matrix; (EVs), extracellular vesicles; (Exos), exosome; (IDD), intervertebral disc degeneration; (IVD), intervertebral disc; (LBP), Low back pain; (NP), nucleus pulposus; (NPCS), NP-based cell delivery system; (PEGDA/DAFM), polyethylene glycol diacrylate/decellularized AF matrix; (SD), sodium deoxycholate; (SDS), sodium dodecyl sulfate; (SIS), small intestinal submucosa; (TGF), transforming growth factor; (bFGF), basic fibroblast growth factor; (hADSCs), human adipose-derived stem cells; (hDF), human dermal fibroblast; (iAF), inner annular fibers; (oAF), outer annular fibers; (sGAG), sulfated glycosaminoglycan; Decellularized matrix; Intervertebral disc degeneration; Regenerative medicine; Tissue engineering.

Graphical abstract

Fig. 1

Diagram depicting the current status of decellularized matrix for repairing intervertebral disc degeneration. (a) The distribution of countries publishing relevant literatures. (b) The distribution of the races resource for decellularization. (c) The distribution of the tissue resource for decellularization. (d) The application of detergent used for decellularization. (e) Reduction of glycosaminoglycan during decellularization. (f) Reduction of DNA during decellularization.

Fig. 2

Raw materials for fabricating decellularized matrix repairing intervertebral disc (IVD) degeneration. (a) Nucleus pulposus derived from different segmental IVD. Adapted with permission from Ref. [21], copyright 2017 Elsevier Inc. (b) Schematic diagram depicting the IVD. Adapted with permission from Ref. [39], copyright 2020 Mary Ann Liebert Inc. (c) Fabrication and characterization of patch for annulus fibrosus repair using pericardial tissue. Adapted with permission from Ref. [40], copyright 2017 John Wiley and Sons Ltd. (d) Fabrication and characterization of patch for annulus fibrosus repair using pericardial tissue. Adapted with permission from Ref. [43], copyright 2020 Frontiers Media S.A. (e) Fabricating an injectable nucleus pulposus cell-modifed decellularized scaffold using small intestinal submucosa. Adapted with permission from Ref. [46], copyright 2017 Impact Journals LLC.

Fig. 3

Optimization of decellularization methods. (a) DAPI staining of decellularised NP treated with SDS for different time. Adapted with permission from Ref. [71], copyright 2019 Elsevier. (b) Representative macroscopic images of annulus fibrosus before and after decellularization. Adapted with permission from Ref. [54], copyright 2014 Public Library of Science. (c) Schematic overview of whole bovine tail IVD decellularization process and time-line. Adapted with permission from Ref. [36], copyright 2018 John Wiley and Sons Inc. (d) Hematoxylin and eosin (H&E) staining and picrosirius red staining evaluating the decelluarization efficency. Adapted with permission from Ref. [73], copyright 2022 SAGE Publications Ltd. (e) Macroscopic image of nucleus pulposus and representative compression stress relaxation curves. Adapted with permission from Ref. [74], copyright 2016 John Wiley and Sons Inc. (f) Decellularized Notochordal cell-Derived matrix prepared using detergent-free method. Adapted with permission from Ref. [14], copyright 2022 American Chemical Society.

Fig. 4

Plain decellularized matrix for repairing intervertebral disc degeneration (IDD). (a) Biomimetic scaffold derived from rabbit nucleus pulposus tissue. Adapted with permission from Ref. [89], copyright 2021 Springer US. (b) Representative macroscopic images of annulus fibrosus before and after decellularization. Adapted with permission from Ref. [43], copyright 2020 Frontiers Media S.A. (c) Viability of the NPC microspheres before and after decellularization, and of hDFs seeded in the NPC acellular matrix and collagen microspheres. Adapted with permission from Ref. [91], copyright 2018 Springer Nature. (d) H&E and Alcian blue staining of intervertebral disc at 2 months after injection. Adapted with permission from Ref. [38], copyright 2016 Impact Journals LLC.

Fig. 5

Hydrogel-form decellularized matrix for repairing intervertebral disc degeneration (IDD). (a) Representative LIVE/DEAD, Alcian blue staining and phase-contrast images of hADSCs cultured on decellularized porcine nucleus pulposus hydrogel. Adapted with permission from Ref. [92], copyright 2013 Mary Ann Liebert Inc. (b) Schematic illustrating the fabrication of genipin-crosslinked decellularized annulus fibrosus hydrogels. Adapted with permission from Ref. [20], copyright 2020 John Wiley and Sons Ltd. (c) Schematic illustration of the porcine nucleus pulposus decellularization. Adapted with permission from Ref. [11], copyright 2022 Wiley. (d) Pictorial illustration of the digest and re-gelation process of the decellularized nucleus pulposus. Adapted with permission from Ref. [21], copyright 2017 Elsevier Inc. (e) Schematic illustration of the fabrication of decellularized nucleus pulposus hydrogel and fresh nucleus pulposus. Adapted with permission from Ref. [3], copyright 2020 SAGE Publications Ltd.

Fig. 6

Decellularized matrix reactivated by bioactive factor or cells. (a) Schematic illustration of the fabrication of injectable decellularized nucleus pulposus-based cell delivery system. Adapted with permission from Ref. [15], copyright 2018 Elsevier BV. (b) Typical MRI and MRI index change after injection of decellularized matrix. Adapted with permission from Ref. [96], copyright 2021 Frontiers Media S.A. (c) Effects of nucleus pulposus cell-derived acellular matrix on the differentiation of mesenchymal stem cells. Adapted with permission from Ref. [35], copyright 2013 Elsevier BV. (d) Schematic illustrating fabrication of PEGDA/DAFM/TGF-β1 hydrogels for AF repair by injecting hydrogels. Adapted with permission from Ref. [99], copyright 2022 KeAi Communications Co. (e) Schematic illustrating the fabrication of injectable nucleus pulposus cell-modifed decellularized scaffold. Adapted with permission from Ref. [46], copyright 2017 Impact Journals LLC.

Fig. 7

Degradability in decellularized materials for repairing IVD. (a) In-vitro tability of GDH cross-linked with different-concentration genipin. Adapted with permission from Ref. [96], copyright 2021 Frontiers Media S.A. (b) sGAG and collagen remnants of decellularized nucleus pulposus cross-linked with 0.02% genipin. Adapted with permission from Ref. [15], copyright 2018 Elsevier BV. (c) Hematoxylin and eosin staining of the DAFM/PECUU2-blended fibrous scaffolds after implantation for 12 weeks. Adapted with permission from Ref. [112], copyright 2022 John Wiley and Sons Inc.

Fig. 8

Signaling pathway involving the biological activity of decellularized matrix on interverbal disc degeneration. (a) Modulating the microenvironment of tissue-specific cell-based decellularized matrix with low oxygen to facilitate NP tissue regeneration. Adapted with permission from Ref. [121], copyright 2012 Lippincott Williams and Wilkins Ltd. (b) Combination of decellularized matrix and hypoxic priming improving the phenotype of degenerate intervertebral disc cells. Adapted with permission from Ref. [44], copyright 2022 Elsevier Inc. (c) NP-like cells differentiation of stem cell via the TGF-β signaling pathway. Adapted with permission from Ref. [71], copyright 2019 Elsevier. (d) Schematic illustrating decellularized matrix fabrication and in vitro and in vivo applications. Adapted with permission from Ref. [6], copyright 2021 KeAi Communications Co.