3D artificial bones for bone repair prepared by computed tomography-guided fused deposition modeling for bone repair

The medical community has expressed significant interest in the development of new types of artificial bones that mimic natural bones. In this study, computed tomography (CT)-guided fused deposition modeling (FDM) was employed to fabricate polycaprolactone (PCL)/hydroxyapatite (HA) and PCL 3D artificial bones to mimic natural goat femurs. The in vitro mechanical properties, in vitro cell biocompatibility, and in vivo performance of the artificial bones in a long load-bearing goat femur bone segmental defect model were studied. All of the results indicate that CT-guided FDM is a simple, convenient, relatively low-cost method that is suitable for fabricating natural bonelike artificial bones. Moreover, PCL/HA 3D artificial bones prepared by CT-guided FDM have more close mechanics to natural bone, good in vitro cell biocompatibility, biodegradation ability, and appropriate in vivo new bone formation ability. Therefore, PCL/HA 3D artificial bones could be potentially be of use in the treatment of patients with clinical bone defects.

Recent Trends in the Development of Bone Regenerative Biomaterials

The goal of a biomaterial is to support the bone tissue regeneration process at the defect site and eventually degrade in situ and get replaced with the newly generated bone tissue. Biomaterials that enhance bone regeneration have a wealth of potential clinical applications from the treatment of non-union fractures to spinal fusion. The use of bone regenerative biomaterials from bioceramics and polymeric components to support bone cell and tissue growth is a longstanding area of interest. Recently, various forms of bone repair materials such as hydrogel, nanofiber scaffolds, and 3D printing composite scaffolds are emerging. Current challenges include the engineering of biomaterials that can match both the mechanical and biological context of bone tissue matrix and support the vascularization of large tissue constructs. Biomaterials with new levels of biofunctionality that attempt to recreate nanoscale topographical, biofactor, and gene delivery cues from the extracellular environment are emerging as interesting candidate bone regenerative biomaterials. This review has been sculptured around a case-by-case basis of current research that is being undertaken in the field of bone regeneration engineering. We will highlight the current progress in the development of physicochemical properties and applications of bone defect repair materials and their perspectives in bone regeneration.

Recent Advances of Chitosan-Based Injectable Hydrogels for Bone and Dental Tissue Regeneration

Traditional strategies of bone repair include autografts, allografts and surgical reconstructions, but they may bring about potential hazard of donor site morbidity, rejection, risk of disease transmission and repetitive surgery. Bone tissue engineering (BTE) is a multidisciplinary field that offers promising substitutes in biopharmaceutical applications, and chitosan (CS)-based bone reconstructions can be a potential candidate in regenerative tissue fields owing to its low immunogenicity, biodegradability, bioresorbable features, low-cost and economic nature. Formulations of CS-based injectable hydrogels with thermo/pH-response are advantageous in terms of their high-water imbibing capability, minimal invasiveness, porous networks, and ability to mold perfectly into an irregular defect. Additionally, CS combined with other naturally-derived or synthetic polymers and bioactive agents has proven to be an effective alternative to autologous bone and dental grafts. In this review, we will highlight the current progress in the development of preparation methods, physicochemical properties and applications of CS-based injectable hydrogels and their perspectives in bone and dental regeneration. We believe this review is intended as starting point and inspiration for future research effort to develop the next generation of tissue-engineering scaffold materials.

A novel electrospun-aligned nanoyarn-reinforced nanofibrous scaffold for tendon tissue engineering

An electrospun-aligned nanoyarn-reinforced nanofibrous scaffold (NRS) was developed for tendon tissue engineering to improve mechanical strength and cell infiltration. The novel scaffold composed of aligned nanoyarns and random nanofibers was fabricated via electrospinning using a two-collector system. The aim of the present study was to investigate three different types of electrospun scaffolds (random nanofibrous scaffold, aligned nanofibrous scaffold and NRS) based on silk fibroin (SF) and poly(l-lactide-co-caprolactone) blends. Morphological analysis demonstrated that the NRS composed of aligned nanoyarns and randomly distributed nanofibers formed a 3D microstructure with relatively large pore sizes and high porosity. Biocompatibility analysis revealed that bone marrow-derived mesenchymal stem cells exhibited a higher proliferation rate when cultured on the NRS compared with the other scaffolds. The mechanical testing results indicated that the tensile properties of the NRS were reinforced in the direction parallel to the nanoyarns and satisfied the mechanical requirements for tendon repair. In addition, cell infiltration was significantly enhanced on the NRS. In conclusion, with its improved porosity and appropriate mechanical properties, the developed NRS shows promise for tendon tissue engineering applications.

Comparative studies of thermogels in preventing post-operative adhesions and corresponding mechanisms

Thermogelling PLGA–PEG–PLGA, PCGA–PEG–PCGA, and PCL–PEG–PCL triblock copolymers and their efficacies of prevention of post-surgical peritoneal adhesions in rabbits were investigated and compared.

Zinc-modified Calcium Silicate Coatings Promote Osteogenic Differentiation through TGF-β/Smad Pathway and Osseointegration in Osteopenic Rabbits

Surface-modified metal implants incorporating different ions have been employed in the biomedical field as bioactive dental implants with good osseointegration properties. However, the molecular mechanism through which surface coatings exert the biological activity is not fully understood, and the effects have been difficult to achieve, especially in the osteopenic bone. In this study, We examined the effect of zinc-modified calcium silicate coatings with two different Zn contents to induce osteogenic differentiation of rat bone marrow-derived pericytes (BM-PCs) and osteogenetic efficiency in ovariectomised rabbits. Ti-6Al-4V with zinc-modified calcium silicate coatings not only enhanced proliferation but also promoted osteogenic differentiation and mineralized matrix deposition of rat BM-PCs as the zinc content and culture time increased in vitro. The associated molecular mechanisms were investigated by Q-PCR and Western blotting, revealing that TGF-β/Smad signaling pathway plays a direct and significant role in regulating BM-PCs osteoblastic differentiation on Zn-modified coatings. Furthermore, in vivo results that revealed Zn-modified calcium silicate coatings significantly promoted new bone formation around the implant surface in osteopenic rabbits as the Zn content and exposure time increased. Therefore, Zn-modified calcium silicate coatings can improve implant osseointegration in the condition of osteopenia, which may be beneficial for patients suffering from osteoporosis-related fractures.

Biomechanical comparison of multilevel lateral interbody fusion with and without supplementary instrumentation: a three-dimensional finite element study

Background

Lateral lumbar interbody fusion (LLIF) is a popular, minimally invasive technique that is used to address challenging multilevel degenerative spinal diseases. It remains controversial whether supplemental instrumentation should be added for multilevel LLIF. In this study, we compared the kinematic stability afforded by stand-alone lateral cages with those supplemented by bilateral pedicle screws and rods (PSR), unilateral PSR, or lateral plate (LP) fixation using a finite-element (FE) model of a multi-level LLIF construct with simulated osteoporosis. Additionally, to evaluate the prospect of cage subsidence, the stress change characteristics were surveyed at cage-endplate interfaces.

Methods

A nonlinear 3-dimensional FE model of the lumbar spine (L2 to sacrum) was used. After validation, four patterns of instrumented 3-level LLIF (L2-L5) were constructed for this analysis: (a) 3 stand-alone lateral cages (SLC), (b) 3 lateral cages with lateral plate and two screws (parallel to endplate) fixated separately (LPC), (c) 3 lateral cages with bilateral pedicle screw and rod fixation (LC + BPSR), and (d) 3 lateral cages with unilateral pedicle and rod fixation (LC + UPSR). The segmental and overall range of motion (ROM) of each implanted condition were investigated and compared with the intact model. The peak von Mises stresses upon each (superior) endplate and the stress distribution were used for analysis.

Results

BPSR provided the maximum reduction of ROM among the configurations at every plane of motion (66.7–90.9% of intact spine). UPSR also provided significant segmental ROM reduction (45.0–88.3%). SLC provided a minimal restriction of ROM (10.0–75.1%), and LPC was found to be less stable than both posterior fixation (23.9–86.2%) constructs. The construct with stand-alone lateral cages generated greater endplate stresses than did any of the other multilevel LLIF models. For the L3, L4 and L5 endplates, peak endplate stresses caused by the SLC construct exceeded the BPSR group by 52.7, 63.8, and 54.2% in flexion, 22.3, 40.1, and 31.4% in extension, 170.2, 175.1, and 134.0% in lateral bending, and 90.7, 45.5, and 30.0% in axial rotation, respectively. The stresses tended to be more concentrated at the periphery of the endplates.

Conclusions

SLC and LPC provided inadequate ROM restriction for the multilevel LLIF constructs, whereas lateral cages with BPSR or UPSR fixation provided favorable biomechanical stability. Moreover, SLC generated significantly higher endplate stress compared with supplemental instrumentation, which may have increased the risk of cage subsidence. Further biomechanical and clinical studies are required to validate our FEA findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1387-6) contains supplementary material, which is available to authorized users.

Advances of Naturally Derived and Synthetic Hydrogels for Intervertebral Disk Regeneration

Intervertebral disk (IVD) degeneration is associated with most cases of cervical and lumbar spine pathologies, amongst which chronic low back pain has become the primary cause for loss of quality-adjusted life years. Biomaterials science and tissue engineering have made significant progress in the replacement, repair and regeneration of IVD tissue, wherein hydrogel has been recognized as an ideal biomaterial to promote IVD regeneration in recent years. Aspects such as ease of use, mechanical properties, regenerative capacity, and their applicability as carriers for regenerative and anti-degenerative factors determine their suitability for IVD regeneration. This current review provides an overview of naturally derived and synthetic hydrogels that are related to their clinical applications for IVD regeneration. Although each type has its own unique advantages, it rarely becomes a standard product in truly clinical practice, and a more rational design is proposed for future use of biomaterials for IVD regeneration. This review aims to provide a starting point and inspiration for future research work on development of novel biomaterials and biotechnology.

Preparation and biocompatibility evaluation of apatite/wollastonite-derived porous bioactive glass ceramic scaffolds

An apatite/wollastonite-derived (A/W) porous glass ceramic scaffold with highly interconnected pores was successfully fabricated by adding a plastic porosifier. The morphology, porosity and mechanical strength were characterized. The results showed that the glass ceramic scaffold with controllable pore size and porosity displayed open macropores. In addition, good in vitro bioactivity was found for the scaffold obtained by soaking it in simulated body fluid. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffold, and the adhesion and proliferation of MSCs were determined using MTT assay and environmental scanning electron microscopy (ESEM). The results revealed that the scaffold was biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity were investigated by implanting both the pure scaffold and the MSC/scaffold construct in rabbit mandibles and studying histologically. The results showed that the glass ceramic scaffold exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffold observably improved the efficiency of new bone formation, especially at the initial stage after implantation. However, the glass ceramic scaffold showed the same good biocompatibility and osteogenicity as the hybrid one at the later stage. These results indicate that porous bioactive scaffolds based on the original apatite-wollastonite glass ceramic fulfil the basic requirements of a bone tissue engineering scaffold.

Dual targeting curcumin loaded alendronate-hyaluronan- octadecanoic acid micelles for improving osteosarcoma therapy

INTRODUCTION

Curcumin (CUR) is a general ingredient of traditional Chinese medicine, which has potential antitumor effects. However, its use clinically has been limited due to its low aqueous solubility and bioavailability. In order to improve the therapeutic effect of CUR on osteosarcoma (i.e., bone cancer), a multifunctional micelle was developed here by combining active bone accumulating ability with tumor CD44 targeting capacity.

METHODS

The CUR loaded micelles were self-assembled by using alendronate-hyaluronic acid-octadecanoic acid (ALN-HA-C18) as an amphiphilic material. The obtained micelles were characterized for size and drug loading. In addition, the in vitro release behavior of CUR was investigated under PBS (pH 5.7) medium containing 1% Tween 80 at 37℃. Furthermore, an hydroxyapatite (the major inorganic component of bone) affinity experiment was studied. In vitro antitumor activity was evaluated. Finally, the anti-tumor efficiency was studied.

RESULTS

The size and drug loading of the CUR loaded ALN-HA-C18 micelles were about 118 ± 3.6 nm and 6 ± 1.2%, respectively. CUR was released from the ALN-HA-C18 micelles in a sustained manner after 12 h. The hydroxyapatite affinity experiment indicated that CUR loaded ALN-HA-C18 micelles exhibited a high affinity to bone. CUR loaded ALN-HA-C18 micelles exhibited much higher cytotoxic activity against MG-63 cells compared to free CUR. Finally, CUR loaded ALN-HA-C18 micelles effectively delayed anti-tumor growth properties in osteosarcoma bearing mice as compared with free CUR.

CONCLUSION

The present study suggested that ALN-HA-C18 is a novel promising micelle for osteosarcoma targeting and delivery of the hydrophobic anticancer drug CUR.

A novel electrospun-aligned nanoyarn/three-dimensional porous nanofibrous hybrid scaffold for annulus fibrosus tissue engineering

Introduction

Herniation of the nucleus pulposus (NP) because of defects in the annulus fibrosus (AF) is a well-known cause of low back pain. Defects in the AF thus remain a surgical challenge, and efforts have been made to develop new techniques for closure and repair. In this study, we developed an electrospun aligned nanoyarn scaffold (AYS) and nanoyarn/three-dimensional porous nanofibrous hybrid scaffold (HS) for AF tissue engineering.

Methods

The AYS was fabricated via conjugated electrospinning, while the aligned nanofibrous scaffold (AFS) was prepared by traditional electrospinning as a baseline scaffold. The HS was constructed by freeze-drying and cross-linking methods. Scanning electron microscopy and mechanical measurement were used to characterize the properties of these scaffolds. Bone marrow derived mesenchymal stem cells (BMSCs) were seeded on scaffolds, and cell proliferation was determined by CCK-8 assay, while cell infiltration and differentiation were assessed by histological measurement and quantitative real-time polymerase chain reaction, respectively.

Results

Morphological measurements showed that AYS presented a relatively better three-dimensional structure with larger pore sizes, higher porosity, and better fibers’ alignment compared to AFS. Mechanical testing demonstrated that the tensile property of AFS and AYS was qualitatively similar to the native AF tissue, albeit to a lesser extent. When BMSCs were seeded and cultured on these scaffolds, the number of cells cultured on HS and AYS was found to be significantly higher than that on AFS and culture plate after 7 days of culture (P<0.05). In addition, cell infiltration was significantly higher in HS when compared with AFS and AYS (P<0.05). A part of BMSCs ingressed into the inner part of AYS upon long-term in vitro culture. No significant difference was observed between AFS and AYS in terms of the median infiltration depth (P>0.05). BMSCs seeded on AYS demonstrated an increased expression of COL1A1, while the expression levels of SOX-9, COL2A1, and Aggrecan were higher in HS compared to other scaffolds (P<0.05).

Conclusion

These findings indicate that HS makes a proper scaffold for the AF tissue engineering as it replicates the axial compression and tensile property of AF, thereby providing a better platform for cell infiltration and cell–scaffold interaction.

Transplantation of Hypoxic-Preconditioned Bone Mesenchymal Stem Cells Retards Intervertebral Disc Degeneration via Enhancing Implanted Cell Survival and Migration in Rats

Objective

Special hypoxic and hypertonic microenvironment in intervertebral discs (IVDs) decreases the treatment effect of cell transplantation. We investigated the hypothesis that hypoxic preconditioning (HP) could improve the therapeutic effect of bone mesenchymal stem cells (BMSCs) to IVD degeneration.

Methods

BMSCs from green fluorescent protein-transgenic rats were pretreated with cobalt chloride (CoCl₂, 100 μM, 24 h) for hypoxic conditions in vitro. Apoptosis (related pathways of caspase-3 and bcl-2) and migration (related pathways of HIF-1α and CXCR4) were detected in BMSCs. In vivo, BMSCs and HP BMSCs (H-BMSCs) were injected into the rat model of IVD degeneration. The IVD height, survival, migration, and differentiation of transplanted BMSCs and matrix protein expression (collagen II, aggrecan, and MMP-13) were tested.

Results

H-BMSCs could extensively decrease IVD degeneration by increasing IVD height and collagen II and aggrecan expressions when compared with BMSCs. Significantly, more GFP-positive BMSCs were observed in the nucleus pulposus and annulus fibrosus regions of IVD. HP could significantly decrease BMSC apoptosis (activating bcl-2 and inhibiting caspase-3) and improve BMSC migration (increasing HIF-1α and CXCR4) in vitro.

Conclusion

HP could significantly enhance the capacity of BMSCs to repair DDD by increasing the survival and migration of implanted cells and increasing matrix protein expression.

Combined anterior C2-C3 fusion and C2 pedicle screw fixation for the treatment of unstable hangman's fracture: a contrast to anterior approach only

STUDY DESIGN

A retrospective clinical study was used to evaluate the effect of a new surgical treatment of the hangman's fractures.

OBJECTIVE

To determine the treatment efficacy of combined anterior C2-C3 reduction and fusion and posterior compressive C2 pedicle screw fixation for the management of unstable hangman's fractures.

SUMMARY OF BACKGROUND DATA

The classification of hangman's fractures as proposed by Levine-Edwards was used to classify and guide the treatment of these injuries. Most of these fractures respond to a variety of conservative therapies, but recently, earlier surgery has been increasingly advocated by authors from several countries for the rapid stabilization of these fractures. If surgery is indicated, an anterior approach using a C2-C3 reduction and fusion is preferred usually. Another well-accepted surgical method is the direct transpedicular osteosynthesis by the dorsal approach. However, there was rare report of the combined use of these 2 techniques.

METHODS

A group of 45 surgical patients were all diagnosed with radiograph, magnetic resonance imaging (MRI), and 3D CT scans. Initial and final radiographs were measured for anterior translation and angulation of the C2-C3 complex. Initial external skull traction with extension was used in all patients after admission to reduce the fracture. Then an anterior C2-C3 discectomy followed by an interbody fusion and locking plate fixation was performed. Intraoperative reduction was confirmed by fluoroscopic control. About 29 patients therefore received anterior surgeries only since satisfactory reduction was achieved during the procedure. For the 16 patients who had persistent large residual gaps after the anterior procedure, additional same stage posterior C2 compressive pedicle screws were placed. Clinical and radiologic comparisons were performed in these 2 groups.

RESULTS

The follow-up ranged from 24 to 54 months, with an average 33.6 months. There was radiographic evidence of continuity of the fracture and the bone graft seen at 4.7 months on average. Neck pain and neurologic deficits resolved in nearly all patients after surgery. The anterior translation of anterior-posterior surgery group decreased more significant compared to anterior surgery group, although with no statistical significance. The fractures were closed with a slight gap no more than 2 mm in anterior-posterior surgery group. The residual kyphosis in anterior-posterior surgery group was still a little larger than it in anterior surgery group. No internal fixation failures or infections were observed.

CONCLUSION

We believe that the need for single stage 360° fusion of hangman's fractures can be somewhat predicted by a combination of high resolution imaging. For hangman's fractures with significant deformity and gapping, it is our experience that immediate single-stage anterior-posterior reduction, instrumentation, and arthrodesis achieve superior postoperative reduction and long-term functional outcomes.

In vitro and in vivo evaluation of zinc-modified ca-si-based ceramic coating for bone implants

The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I), osteocalcin), insulin-like growth factor-I (IGF-I), and transforming growth factor-β1 (TGF-β1). The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC) in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone.

MiR-202-3p regulates interleukin-1β-induced expression of matrix metalloproteinase 1 in human nucleus pulposus

MicroRNAs (miRNAs), small noncoding RNA molecules, have emerged as important factors during intervertebral disc degeneration. This study was to determine whether miR-202-3p regulates interleukin-1β (IL-1β)-induced expression of matrix metalloproteinase 1 (MMP-1) in human nucleus pulposus (NP) cells. Human NP cells were stimulated with IL-1β in vitro. MicroRNA arrays were used to determine the expression profile of 1971 human miRNAs and the miRNAs targets were identified using bioinformatics. In IL-1β-stimulated NP cells, 10 microRNAs were down-regulated, 2 microRNAs were up-regulated. There was a significant reduction in hsa-miR-202-3p (miR-202-3p) expression in the severe degenerative disc compared with mild degenerative disc. Down-regulation of miR-202-3p expression by IL-1β was correlated with up-regulation of MMP-1 expression in human NP cells. IL-1β-induced activation of MAP kinase (MAPK) and nuclear factor-κB (NF-κB) decreased miR-202-3p expression and induced MMP-1 expression. MiR-202-3p suppressed IL-1β-induced MMP-1 production. Conversely, treatment with anti-miR-202-3p remarkably increased MMP-1 production. In addition, mutation of the miR-202-3p binding site in the 3'-UTR of MMP-1 mRNA abolished miR-202-3p-mediated repression of reporter activity. Functional analysis showed that miR-202-3p could decrease type II collagen degradation, whereas overexpression of MMP-1 by Lentiviral-shMMP-1 abolished the effect of miR-202-3p on type II collagen degradation. These results suggest that miR-202-3p is an important regulator of MMP-1 in human nucleus pulposus and may contribute to the development of intervertebral disc degeneration.

Preliminary studies on the anti-osteoporosis activity of Baohuoside I

The aim of the present study was to investigate the anti-osteoporotic activity of Baohuoside I, an active component of Herba Epimedii. Effects of Baohuoside I on the differentiation of BMSCs and the formation of adipocytes were evaluated using alkaline phosphatase staining and methylene blue staining method, respectively. Osteoporosis model was established in ovariectomized rats prior to the measurement of the serum SOD and MDA levels as well as the expression of inflammatory cytokines protein in the rats' tissues after treatment with Baohuoside I using ELISA assay kits. The estrogen-like effect of Baohuoside I was also measured on HeLa cells. The positive rates of ALP staining in Baohuoside I groups were significantly higher (p < 0.01) compared with the normal group, with no obvious adipocyte formation observed in the groups that received Baohuoside I treatments. The levels of inflammatory markers (IL-1β, TNF-α, IL-6 and IL-8) in the treated groups were significantly lower (p < 0.05) than in the model group. Likewise, the treated groups exhibited a significantly higher (p < 0.05) serum levels of MDA compared with the model group, while SOD levels were markedly lower (p < 0.05) in a dose-dependent fashion. Baohuoside I showed no estrogen-like effect on HeLa cells upon treatment with the drug. Collectively, these results indicated that the anti-osteoporotic activity of Baohuoside I could be related to the induction of BMSCs differentiation into osteoblasts coupled with the inhibition of adipocyte formation, regulation of immune functions, and antioxidant activity.

Standalone oblique lateral interbody fusion vs. combined with percutaneous pedicle screw in spondylolisthesis

Background

To compare standalone oblique lateral interbody fusion (OLIF) vs. OLIF combined with posterior bilateral percutaneous pedicle screw fixation (OLIF combined) for the treatment of lumbar spondylolisthesis.

Methods

This was a retrospective study of patients who underwent standalone OLIF or combined OLIF between 07/2014 and 08/2017 at two hospitals in China. Direct decompressions were not performed. Visual analog scale (VAS), Oswestry Disability Index (ODI), satisfaction rate, anterior/posterior disc heights (DH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, fusion rate, and complications were analyzed. All imaging examinations were read independently by two physicians and the mean measurements were used for analysis.

Results

A total of 73 patients were included: 32 with standalone OLIF and 41 with combined OLIF. The total complication rate was 25.0% with standalone OLIF and 26.8% with combined OLIF. There were no differences in VAS and ODI scores by 2 years of follow-up, but the scores were better with standalone OLIF at 1 week and 3 months (P < 0.05). PDH and FW was smaller in the combined OLIF group compared with the standalone OLIF group before and after surgery (all P < 0.05). There were significant differences in FH before surgery and at 1 week and 3 months between the two groups (all P < 0.05), but the difference disappeared by 2 years (P = 0.111). Cage subsidence occurred in 7.3% (3/41) and 7.3% (3/41) of the patients at 3 and 24 months, respectively, in the combined OLIF group, compared with 6.3% (2/32) and 15.6% (5/32), respectively, in the standalone OLIF group at the same time points (P = 0.287). There was no cage retropulsion in both groups at 2 years. The fusion rate was 85.4%(35/41) in the combined OLIF group and 84.4% (27/32) in the standalone OLIF group at 3 months(P = 0.669). At 24 months, the fusion rate was 100.0% in the combined OLIF group and 93.8% (30/32) in the standalone OLIF group (P = 0.066).

Conclusion

Standalone OLIF may achieve equivalent clinical and radiological outcomes than OLIF combined with fixation for spondylolisthesis. The rate of complications was similar between the two groups. Patients who are osteoporotic might be better undergoing combined rather than standalone OLIF. The possibilty of proof lies within a future prospective study, preferably an RCT.

The prognostic value of elevated vascular endothelial growth factor in patients with osteosarcoma: a meta-analysis and systemic review

BACKGROUND

Osteosarcoma is a primary malignancy of bone. Although new therapies continue to emerge, osteosarcoma-related morbidity and mortality remain high. Various studies have evaluated the prognostic value of VEGF levels in osteosarcoma patients, but they have yielded conflicting results.

METHODS

The 5-year survival of each study was aggregated following a methodological assessment, and a systematic review of eligible studies with meta-analysis and univariate analysis was performed to quantitatively review the correlation of VEGF overexpression with 5-year survival in patients with osteosarcoma.

RESULTS

A total of 387 patients in eleven papers were finally considered to be eligible for inclusion in our analysis. Aggregation of the 6 positive results in Kaplan-Meier curve showed a risk ratio of 2.84 (95% CI: 1.39-5.83, P = 0.004) associated with VEGF-positive conditions in comparison with VEGF-negative conditions, suggesting that there was significant association between VEGF positive and the 5-year mortality. But univariate analysis of eleven studies showed that there was a small inverse but not significant relationship between VEGF expression level and the 5-year survival of osteosarcoma patients, but stage III, neo-chemotherapy, the primary tumor location, osteoblastic histological subtype and the source of patients showed a significant impact on the 5-year survival of patients.

CONCLUSIONS

The prognostic significance of VEGF expression in all its isoforms is still unknown based on the limited data available, but we find VEGF165 may play an important role. Future studies should examine the relationship between VEGF isoform expression and patients' survival and the relationship between VEGF isoform expression and EMMPRIN expression, which could be helpful for predicting the prognosis of patients with osteosarcoma. Once the conclusion of whether the VEGF and its isoforms playing a role in osteosarcoma were reached, it would help guide clinical decision-making regarding therapy and outcomes. In addition, we recommend a >25% positive staining of the cells as a VEGF-positive cut-off value in immunohistochemistry, since we find a relatively strict detecting method is likely to yield significant result in the 5-year survival of patients.

Nicotinamide Phosphoribosyltransferase Inhibitor APO866 Prevents IL-1β-Induced Human Nucleus Pulposus Cell Degeneration via Autophagy

BACKGROUND/AIMS

Intervertebral discs consist of an extracellular matrix (ECM) with a central gelatinous nucleus pulposus (NP) enclosed in an outer layer known as the annulus fibrosus. ECM metabolic disorders result in loss of boundary between the annulus fibrosus and NP, which can lead to intervertebral disc degeneration (IDD). Proinflammatory cytokines, such as interleukin (IL)-1β, mediate the progression of IDD. Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the first step in the biosynthesis of nicotinamide adenine dinucleotide (NAD) and is known to be induced by IL-1β. APO866 is an inhibitor of NAD biosynthesis and is involved in autophagy. LC3 (microtubule-associated protein 1 light chain 3) is a key regulator of autophagy and is used as an indicator of increased autophagy. Herein, we investigate the role of APO866 in regulating autophagy in NP cells and IL-1β mediated NP cell degeneration and apoptosis.

METHODS

NP cells were extracted from IDD tissues and cultured in DMEM/F12 medium. Nampt was induced by different concentrations of IL-1β (0, 0.5, 1, 5, 10 ng/mL) for 24 h or NP cells were treated with 10 ng/mL IL-1β for 0, 6, 12, 48 h. QRT-PCR and western blots were used to detect Nampt and ECM-related protein expression in NP tissue of patients with IDD and in NP cells. Confocal analysis was used to detect membrane-bound LC3, Aggrecan, and Collagen II.

RESULTS

Nampt is expressed in NP tissue at higher levels in severe grades of IDD (Grade IV and V) compared with low grades (Grade II and III). In NP cells, 10 ng/mL IL-1β induced Nampt expression for 48 h, increased expression of the degradative-associated proteins, ADAMTS4/5 and MMP-3/13, and decreased expression of ECM-related proteins, Aggrecan and Collagen II. However, the Nampt inhibitor APO866 blocked IL-1β induction, and the knockdown of Nampt expression increased the expression of ECM proteins that were inhibited by IL-1β. Moreover, evidence provided by the autophagic markers LC3 and Beclin-1 indicated that APO866 induced NP cell autophagy. Furthermore, although APO866 inhibited the downregulated expression of ECM-related proteins by IL-1β, this function was blocked by autophagy inhibitor, 3-methyladenine.

CONCLUSION

APO866 protects NP cells and induces autophagy by inhibiting IL-1β-induced NP cell degeneration and apoptosis, which may have therapeutic potential in IDD.

Hypoxic preconditioned bone mesenchymal stem cells ameliorate spinal cord injury in rats via improved survival and migration

The unique hypoxic inflammatory microenvironment observed in the spinal cord following spinal cord injury (SCI) limits the survival and efficacy of transplanted bone mesenchymal stem cells (BMSCs). The aim of the present study was to determine whether hypoxic preconditioning (HP) increased the therapeutic effects of BMSC on SCI. BMSCs were pretreated with cobalt chloride (CoCl2) in vitro, and the proliferative apoptotic and migratory abilities of these hypoxic BMSCs (H‑BMSCs) were assessed. BMSCs and H‑BMSCs derived from green fluorescent protein (GFP) rats were transplanted into SCI rats in vivo. The neurological function, histopathology, inflammation, and number and migration of transplanted cells were examined. HP significantly enhanced BMSC migration (increased hypoxia inducible factor 1α and C‑X‑C motif chemokine receptor 4 expression) and tolerance to apoptotic conditions (decreased caspase‑3 and increased B‑cell lymphoma 2 expression) in vitro. In vivo, H‑BMSC transplantation significantly improved neurological function, decreased spinal cord damage and suppressed the inflammatory response associated with microglial activation. The number of GFP‑positive cells in the SCI core and peripheral region of H‑BMSC animals was increased compared with that in those of BMSC animals, suggesting that HP may increase the survival and migratory abilities of BMSCs and highlights their therapeutic potential for SCI.