Injectable hydrogel provides growth‐permissive environment for human nucleus pulposus cells

Abstract

Degeneration of intervertebral discs (IVDs) results in an overall alteration of the biomechanics of the spinal column and becomes a major cause of low back pain. In this study, an injectable hydrogel composite is fabricated and characterized as a potential scaffold for the treatment of degenerated IVDs. Crosslinking of type II collagen-hyaluronic acid (HA) hydrogel with 1-ethyl-3 (3-dimethyl aminopropyl) carbodiimide (EDC) increases the gel stability against collagenase digestion and reduces water uptake in comparison with non-crosslinked gel. Cell viability assay exhibits the proliferation of human nucleus pulposus (HNP) cells in hydrogels. The cells in non-crosslinked gel and the gel crosslinked with a low concentration of EDC (0.1 mM) show superior cell viability and morphology compared with cells in gels crosslinked with higher concentration of EDC. Quantitative PCR assay demonstrates the gene expression of extracellular matrix (ECM) by cells cultured in the gels. The expression of ECM genes by HNP cells in the gels demonstrated the phenotypic change of the cells. This study suggests that the type II collagen-HA hydrogel and crosslinked hydrogel (0.1 mM EDC) are permissive matrix for the growth of HNP cells and can be potentially applied in NP repair.

Effect of optimized collagenase digestion on isolated and cultured nucleus pulposus cells in degenerated intervertebral discs

“…Collagenase belongs to the matrix metalloproteinase family, which can dissolve NP tissues at a certain pH and temperature. [ 12 ] However, under optimal conditions for giving full play to collagenase activity, digestive and NP cell damage is lesser, and is worth of further study.…”

Biomimetic nucleus pulposus scaffold created from bovine caudal intervertebral disc tissue utilizing an optimal decellularization procedure

“…Success of such approaches rely largely upon the development of a biomaterial scaffold that mimics the native NP biochemistry and mechanical properties which can function to deliver, protect, and provide instructive cues to stem cells such that they attain the appropriate phenotype and produce NP‐specific ECM. Examples of biomaterial scaffolds investigated for NP TE to date include preformed and injectable hydrogels composed of type II collagen‐hyaluronic acid and cross‐linked alginate …”

Intradiscal Therapeutics for Degenerative Disc Disease

“…Injectable hyaluronate hydrogels (HH) are cellfree intradiscal matrix implantations that have been proposed to limit disc degeneration following a nucleotomy procedure. HH have an antiinflammatory effect within the intervertebral disc, and also provide a growth-permissive environment for NP cells and MSCs (Isa et al 2015;Priyadarshani et al 2016).…”

“…Human NP cells cultured for 8 weeks within a HH showed functional matrix accumulation and synthesis, and these results were higher at lower density of NP cells (20 million cells per millilitre) (Kim et al 2015). A study cross-linking type-II collagen HH with 1-ethyl-3(3-dimethyl aminopropyl) carbodiimide (EDC) was also demonstrated to be a viable growth medium for culturing of NP cells (Priyadarshani et al 2016). Another hydrogel with chitosan and hyaluronic acid cross-linked with glycerol phosphate promoted ADSC proliferation and nucleus pulposus differentiation (Zhu et al 2017).…”