The 10-year follow-up study showed that the long-term clinical outcomes of MED are satisfactory and better than those of the traditional discectomy procedure. The MED procedure is both feasible and efficacious for the treatment of LDH.

Introduction Cartilage endplate (CEP) degeneration is usually accompanied by loss of cellularity, and this loss may be a crucial key factor in initiation and development of degenerative disc disease. The study of cell types in degenerated CEP could help in understanding CEP etiopathogenesis, and may help in devising new treatments, especially if the presence of progenitor cells could be demonstrated. The aim of this study was to determine if progenitor cells existed in degenerated human CEP. Materials and methods Cells isolated from CEP were cultured in a three-dimensional agarose suspension to screen for proliferative cell clusters. Cell clusters were then expanded in vitro and the populations were analyzed for colony forming unit, immunophenotype, multilineage induction, and expression of stem cell-related genes. Results The presence of progenitor cells in degenerated human CEP is indicated by the results of CFU, immunophenotype, multilineage induction, and expression of stem cell-related genes. Conclusions We believe that this is the first study which has conclusively shown the presence of progenitor cells in degenerated CEP. The finding of this study may influence the clinical management of degenerative disc disorder.

Introduction Advancement in tissue engineering provides a promising approach to recover the functionality of the degenerated intervertebral disc. In our study, a nucleus pulposus (NP) cell-seeded collagen II/hyaluronan/chondroitin-6-sulfate (CII/HyA/CS) tri-copolymer construct was implanted into the disc space directly after nucleotomy in a rabbit model. The aim of this study was to investigate whether the NP cell-seeded CII/HyA/CS tri-copolymer constructs could regenerate the degenerated disc in vivo after implantation into the rabbit nucleotomy model. Materials and Methods NP cells isolated from thoracic and lumbar spines of New Zealand white rabbits of about 3 weeks of age and 1 kg in weight were labeled with a 5- (and-6)-carboxyflurescein diacetate succinimidyl ester (CFDA-SE) fluorescent dye and seeded within the CII/HyA/CS scaffold by a centrifugation method. After in vitro culture for 1 week, NP cell-seeded CII/HyA/CS tri-copolymer constructs were allografted into the disc defects of recipient rabbit immediately after nucleotomy of the lumbar spine. The Bradner disc index and the T2-weighted signal intensity index were determined using lateral plane radiographs and magnetic resonance imaging at 4, 12, and 24 weeks after the operation. Finally, the operated discs were explanted for gross morphological observation, histological evaluation, and cell viability assessment. Animals with only nucleotomy and cell-free CII/HyA/CS scaffold implantation served as controls. Results In our study, we could demonstrate that the T2-weighted signal intensity index of the operated discs decreased in all three groups 1 month after surgery and the index of the cell-containing scaffold insertion group was significantly higher than that of the other two groups. After 24 weeks, the index of the cell-containing scaffold insertion group increased significantly. However, further decline was observed in both the noninsertion group and the scaffold insertion group. In radiographic analysis, the narrowing of the intervertebral disc space was significantly retarded by the cell-scaffold hybrids implantation up to 24 postoperative weeks. Moreover, the gross morphology and histological evaluation indicated that the allografted NP cells were viable and showed extracellular matrix production. Conclusion In our study, we had constructed rabbit NP cell-seeded CII/HyA/CS tri-copolymer implants in vitro. Immediately after nucleotomy of the recipient rabbit, we allografted the precultured cell-scaffold hybrids into the lacuna of the disc. Results documented survival of the allografted NP cells and extracellular matrix deposition, which finally resulted in maintenance of disc height and restoration of T2-weighted signal intensity on magnetic resonance imaging. Disclosure of Interest None declared

Background: Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine that regulates inflammatory reactions and the pathophysiology of many inflammatory diseases. Intervertebral disc (IVD) degeneration is characterized by an inflammatory reaction, but the potential role of MIF in IVD degeneration has not been determined. Recent studies have shown that MIF and its receptor, CD74, are involved in regulating the migration of human mesenchymal stem cells (MSCs); Thus, MIF might impair the ability of mesenchymal stem cells (MSCs) to home to injured tissues. Our previous studies indicated that cartilage endplate (CEP)-derived stem cells (CESCs) as a type of MSCs exist in human degenerate IVDs. Here, we investigate the role of MIF in regulating the migration of CESCs.

Introduction This study aims to investigate the bioactivity of collagen II/hyaluronan/chondroitin-6-sulfate tri-copolymer as bionic scaffold for nucleus pulposus (NP) tissue engineering. Materials and Methods Collagen II (C II) (pH 1-2) was mixed with hyaluronan (HyA) and lyophilized to prepare C II/HyA matrices. Chondroitin 6-sulfate (6-CS) was covalently attached to the C II/HyA matrices using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Then, cells were expanded from rabbit NP and seeded in the tri-copolymer scaffold. Cell-scaffold hybrids were maintained for up to 28 days in culture. Cell viability/proliferation, extracellular matrix (ECM)-related gene expression, and the content of sulfated glycosaminoglycans (s-GAG) were evaluated. Results When cultured for 28 days, the cell-scaffold hybrids maintained active cell viability/proliferation and exhibited a significantly increased s-GAG content. In addition, rabbit NP cells cultured in the scaffold demonstrated a significantly higher level of C II and aggrecan gene expression and a significantly lower level of Collagen I (C I) gene expression when compared with that of monolayer cells. Histological studies and scanning electron microscopy (SEM) further indicated newly secreted ECM deposits in the scaffolds. Conclusion In conclusion, the C II/HyA-CS scaffold may be an alternative material for NP tissue engineering due to its satisfactory bioactivity, and it deserves further in vivo investigation. Disclosure of Interest None declared

Introduction Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is one popular posterior lumbar fusion surgery. The immediately biomechanical stability after unilateral or bilateral facetectomy of direct decompression is dependent on the type of supplement pedicle screw fixation used. The monoaxial pedicle screw and plate (PSP) has been approved for clinical use for added stabilization after cage instrumentation, especially for axial rotation stabilization. However, little biomechanical data exist comparing PSP fixation with bilateral multiaxial pedicle screw and rod (PSR) fixation. Materials and Methods Eight L3-L6 calf spines were instrumented with posterior cages at L4-L5 after intact kinematic analysis. The TLIF model was generated by clinical procedure and fixed with multiaxial PSR or monoaxial PSP by randomized sequence. A pure moment (±5.0 Nm) were applied to specimens to induce flexion/extension, lateral bending (LB) (left + right), and axial rotation (AR) (left + right) while recording intact versus instrumented range of motion (ROM). Two monoaxial strain gauges were instrumented at the surface of L4 and L5 vertebrae body each, to record the strain distribution under the flexion and lateral bending motion. Destructive tests of monoaxial PSR, multiaxial PSR, and monoaxial PSP construct were used to record the modes of failure, yield strength, and yield stiffness in a static compression bending test. Results Monoaxial PSP fixation significantly reduced ROM (p < 0.001) at the lumbar level (flexion/extension: 88.7%; LB: 94.7%; AR: 53.8%) relative to the intact condition. Multiaxial PSR fixation afforded the similar ROM reductions (p < 0.001) relative to the intact condition (flexion/extension: 83.1%; LB: 92.6%; AR: 42.3%). The strain distribution with monoaxial PSP fixation is not significantly larger than that with multiaxial PSR fixation when different loading conditions were applied (flexion vs. lateral bending). The strain distribution of L4 in both fixation conditions was significantly less than that in intact condition in lateral bending. The yield stiffness of the monoaxial PSP construct is significantly less than that of the monoaxial PSR construct (p < 0.001), while the yield strength of the monoaxial PSP construct is significantly larger than that of the monoaxial PSR construct (p < 0.001). Conclusion Based on these biomechanical findings, monoaxial PSP fixation and multiaxial PSR fixation are equal to afford the immediate stability after TLIF surgery. The property of low yield stiffness in monoaxial PSP construct has the potential to reduce the stress-shielding effect of the fusion segment. Disclosure of Interest None declared

Introduction Parathyroid hormone-related peptide (PTHrP) is an important inductive factor during chondrogenesis of mesenchymal stem cells (MSCs). PTHrP induces chondrogenesis and suppresses hypertrophy, yet the lack of an efficient delivery system limits its use for cartilage tissue engineering in clinical application. Materials and Methods In this study, a peptide of seven amino acids was first used to engineer PTHrP to construct a collagen-targeting system. This peptide functioned as a collagen-binding domain (CBD) to specially target the PTHrP to collagen. ELISA assay was used to determine the collagen-binding ability of CBD-PTHrP. The effect of CBD-PTHrP on chondrogenesis was measured by an in vitro pellet assay in bone marrow-derived MSCs (BM-MSCs). Results The CBD peptide promoted the binding of CBD-PTHrP to collagen when compared with NAT-PTHrP. Furthermore, the recombinant protein CBD-PTHrP induced the expression of COL2A1 and Sox-9, inhibited the expression of COL1A1 at the mRNA and protein levels as effectively as NAT-PTHrP. Safranin-O and immunohistochemistry for collagen types I, II, X and Sox-9 generally paralleled qRT-PCR and Western blotting findings with minor variations. Conclusion Our study demonstrated that CBD-PTHrP is a collagen-targeting system and promotes in vitro chondrogenesis in BM-MSCs. We suggest that this is an efficient delivery system for cartilage tissue engineering in clinical application. Disclosure of Interest None declared

Introduction In a general view of anatomy, intervertebral disc is composed of three parts: annulus fibrosus, nucleus pulposus (NP), and cartilage endplate. Recently, several types of stem cells were successfully isolated from these corresponding regions, but up to now, no research was performed about which kind of stem cells is the most efficient candidate for NP tissue engineering or for stem cell-based disc regeneration therapy. Materials and Methods In this study, we compared the regenerative potentials of the above-mentioned three kinds of disc-derived stem cells with that of the classic bone marrow (BM)-mesenchymal stem cells (MSCs) in a rabbit disc degeneration model. By magnetic resonance imaging (MRI), X-ray, histology, and so on. Results We found that cartilage endplate-derived stem cells (CESCs) showed superior capacity compared with the annulus fibrosus-derived stem cells (AFSCs), nucleus pulposus-derived stem cells (NPSCs), and BM-MSCs (p< 0.05); in addition, when comparing the CESC group with the normal control group, there existed no statistical difference in X-ray (p>0.05). Those results demonstrated that the CESC-seeded alginate construct performed the most powerful ability for NP regeneration, while AFSCs showed the most inferior potency, NPSCs and BM-MSCs had similar regenerative capacity and located in the middle. Conclusion Our study showed that CESCs might act as an efficient seed cell source for NP tissue engineering, which paved a new way for the biological solution of disc degeneration diseases. Disclosure of Interest None declared