The establishment and biological assessment of a whole tissue‐engineered intervertebral disc with PBST fibers and a chitosan hydrogel in vitro and in vivo

Abstract

Intervertebral disc (IVD) degeneration (IDD) is the main cause of low back pain in the clinic. In the advanced stage of IDD, both cell transplantation and gene therapy have obvious limitations. At this stage, tissue‐engineered IVDs (TE‐IVDs) provide new hope for the treatment of this disease. We aimed to construct a TE‐IVD with a relatively complete structure. The inner annulus fibrosus (AF) was constructed using poly (butylene succinate‐co‐terephthalate) copolyester (PBST) electrospun fibers, and the outer AF consisted of solid PBST. The nucleus pulposus (NP) scaffold was constructed using a chitosan hydrogel, as reported in our previous research. The three components were assembled in vitro, and the mechanical properties were analyzed. AF and NP cells were implanted on the corresponding scaffolds. Then, the cell‐seeded scaffolds were implanted subcutaneously in nude mice and cultured for 4 weeks; then they were removed and implanted into New Zealand white rabbits. After 4 weeks, their properties were analyzed. The PBST outer AF provided mechanical support for the whole TE‐IVD. The electrospun film and chitosan hydrogel simulated the natural structure of the IVD well. Its mechanical property could meet the requirement of the normal IVD. Four weeks later, X‐ray and MR imaging examination results suggested that the height of the intervertebral space was retained. The cells on the TE‐IVD expressed extracellular matrix, which indicated that the cells maintained their biological function. Therefore, we conclude that the whole TE‐IVD has biological and biomechanical properties to some extent, which is a promising candidate for IVD replacement therapies. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2305–2316, 2019.

The nucleus pulposus microenvironment in the intervertebral disc: the fountain of youth?

“…The use of components that are already present in the native microenvironment seem to have a high rate of success. However, the development of scaffolds based on natural materials such as silk (Park et al, 2012), alginate (Du et al, 2019), chitosan (Alinejad et al, 2019;Yuan et al, 2019) or gellan gum Tsaryk et al, 2017) also show good results but are more different from native components. Interesting and positive effects demonstrated by those different strategies, to promote IVD and NP regeneration, rely on the concept of optimally mimicking the microenvironment requiring treatment, and remain to be further elucidated .…”

Disordered Mechanical Stress and Tissue Engineering Therapies in Intervertebral Disc Degeneration

“…Another study used porcine-derived pericardium as multi-laminate AF repair patches (AFRPs) where the pericardium was decellularized and assembled to generate AFRPs. When cross-linked with carbodiimide, which is resistant to collagenase, AFRPs protected the integrity and stabilized the balance of enzymatic metabolism of the degenerated IVD by promoting the migration and proliferation of AF cells in a bovine caudal IVD [97]. Sealing the gap in the disrupted AF is the main need in clinical AF treatment strategy; thus, it is necessary to evaluate the existing repair strategies.…”

Long‐term pre‐clinical evaluation of an injectable chitosan nanocellulose hydrogel with encapsulated adipose‐derived stem cells in an ovine model for IVD regeneration

“…In fact, >50% of asymptomatic individuals 30–39 years of age demonstrate disc degeneration, disc height loss, or bulging (Brinjikji et al., 2015) In the U.S. alone, 280,000 spinal disc surgeries are performed each year, with ∼1 million performed annually worldwide. This is a substantial number, considering that only 10%–15% of IVD prolapses require surgical intervention (Yuan et al., 2019).…”

“…Further experiments have been designed as short‐term in vivo small animal studies, e.g. with implantable scaffolds (Yuan et al., 2019). Yuan et al.…”