Biomaterials and Cell-Based Regenerative Therapies for Intervertebral Disc Degeneration with a Focus on Biological and Biomechanical Functional Repair: Targeting Treatments for Disc Herniation

Abstract

Intervertebral disc (IVD) degeneration is a common cause of low back pain and most spinal disorders. As IVD degeneration is a major obstacle to the healthy life of so many individuals, it is a major issue that needs to be overcome. Currently, there is no clinical treatment for the regeneration of degenerated IVDs. However, recent advances in regenerative medicine and tissue engineering suggest the potential of cell-based and/or biomaterial-based IVD regeneration therapies. These treatments may be indicated for patients with IVDs in the intermediate degenerative stage, a point where the number of viable cells decreases, and the structural integrity of the disc begins to collapse. However, there are many biological, biomechanical, and clinical challenges that must be overcome before the clinical application of these IVD regeneration therapies can be realized. This review summarizes the basic research and clinical trials literature on cell-based and biomaterial-based IVD regenerative therapies and outlines the important role of these strategies in regenerative treatment for IVD degenerative diseases, especially disc herniation.

Recent Advances in Managing Spinal Intervertebral Discs Degeneration

“…The minimally invasive transplantation of different cells (e.g., MSCs, induced pluripotent stem cells (iPSCs), embryonic stem cells (ESCs), NP-derived cells, chondrocyte-like cells) has the potential to support the IVD by differentiating into IVD-like cells and/or by secreting trophic and anti-inflammatory factors. Thus, cell-based therapies can be used to regenerate or at least slow down degeneration, whereas combining cells with a biocompatible material can additionally provide initial mechanical stability and protection after implantation [ 3 , 7 , 90 ].…”

“…MSCs are the most clinically evaluated cell type for disc regeneration therapy, being recognized for their ability to self-renew and differentiate into many tissue types, including chondrogenic and IVD-cell lineages [ 7 , 90 ]. MSCs have also been noted to preserve their multi-directional differential potential after continuous subculture and cryopreservation, being ideal cells for repairing damage caused by senescence and pathological changes [ 9 ].…”

“…Particularly, the degeneration of intervertebral discs (IVDs) has been considered the major cause of low back pain [ 2 , 3 , 4 , 5 ]. Mostly correlated with age, but not exclusively, IVD degeneration (IDD) can further aggravate into connected diseases, such as disc herniation, spinal canal stenosis, and spinal deformities [ 3 , 6 , 7 ]. Thus, proper and prompt treatment should be given to IDD patients to avoid the condition worsening ( Figure 1 ).…”

“…In contrast, in natural IVDs, they are provided by viscoelasticity, thanks to the deformable nature of this soft tissue. Therefore, more direct and effective treatments that address the fundamental underlying pathological conditions must be sought and implemented in practice [ 7 , 8 , 9 , 10 , 11 ].…”

“…In this context, there is an increasing research interest in finding new therapeutic agents that would not only alleviate pain but would also help regenerate damaged IVDs through the restoration of tissue homeostasis [ 12 ]. Recent advances in regenerative medicine and tissue engineering also hold promise for developing better-performing IDD treatment options capable of inhibiting or reversing degenerative processes [ 7 , 13 , 14 ].…”