Jinglong Yan

Curcumin promotes the spinal cord repair via inhibition of glial scar formation and inflammation.

Spinal cord injury (SCI) is a serious clinical situation without any effective therapy to date. Traumatic SCI triggers a complex pathological process including inflammatory response and glial scar formation. In this study, we demonstrated that curcumin, a natural product which functions as an anti-inflammatory agent, inhibited the activation of signal transducer and activator of transcription-3 and NF-kappa B in the injured spinal cord. Curcumin treatment greatly reduced the astrogliosis in SCI mice and significantly decreased the expression of IL-1β and NO, as well as the number of Iba1(+) inflammatory cells at the lesion site. Notably, more residual axons and neurons were protected and significantly improved functional recovery was observed in the curcumin-treated mice, compared to the mice without curcumin treatment. These findings indicate that curcumin promotes spinal cord repair through inhibiting glial scar formation and inflammation and suggests the therapeutic potential of curcumin for SCI.

Sesamin inhibits IL-1β-stimulated inflammatory response in human osteoarthritis chondrocytes by activating Nrf2 signaling pathway

Sesamin, a bioactive component extracted from sesame, has been reported to exert anti-inflammatory and anti-oxidant effects. In this study, we evaluated the anti-inflammatory effects of sesamin on IL-1β-stimulated human osteoarthritis chondrocytes and investigated the possible mechanism. Results demonstrated that sesamin treatment significantly inhibited PGE2 and NO production induced by IL-1β. Sesamin inhibited MMP1, MMP3, and MMP13 production in IL-1β-stimulated chondrocytes. Sesamin also inhibited IL-1β-induced phosphorylation of NF-κB p65 and IκBa. Meanwhile, sesamin was found to up-regulate the expression of Nrf2 and HO-1. However, Nrf2 siRNA reversed the anti-inflammatory effects of sesamin. In conclusion, our results suggested that sesamin showed anti-inflammatory effects in IL-1β-stimulated chondrocytes by activating Nrf2 signaling pathway.

Neuroprotective effect of vaccination with autoantigen-pulsed dendritic cells after spinal cord injury.

BACKGROUND Studies have shown that the development of a properly controlled autoreactive T cell response can serve as a therapeutic approach for spinal cord injury (SCI). Thus, vaccination with mature dendritic cells (DCs) pulsed with central nervous system (CNS) antigens that can prime autoreactive T cells have the potential for treating SCI. MATERIALS AND METHODS Mature DCs pulsed with spinal cord homogenate (SCH), nonpulsed mature DC or phosphate-buffer solution (PBS) were injected into spinal cord-injured mice peritoneally. The functional recovery of spinal cord was measured by Basso mouse scale and footprint analysis. Spinal cord specimen was preserved for immunohistochemical staining to detect T cell infiltration, differentiation of neural stem/progenitor cells, and tissue preservation. RT-PCR and enzyme linked immunosorbent assay (ELISA) was used to detect the expression of cytokines and neurotrophic factors. RESULTS Vaccination with DCs pulsed with SCH promoted pronounced functional recovery from SCI. The neuroprotection induced by SCH-pulsed DCs (SCH-DC) correlated to the accumulation of CD4(+) T cells in the lesion site. SCH-DC markedly affected the production of interferon-γ, interleukin-12, and granulocyte-macrophage colony stimulating factor. SCH-DC also promoted expression of neurotrophic factors in the injured spinal cord and spleen cells. Furthermore, vaccination with SCH-DC enhanced neuronal differentiation of neural stem/progenitor cells, and it led to better tissue preservation. CONCLUSION The results of the present study suggest that DC-mediated immune regulation may be a potential therapeutic approach aimed at shifting the balance between immune and nerve cells in order to treat SCI.

Tumor necrosis factor-alpha is a potential diagnostic biomarker for chronic neuropathic pain after spinal cord injury

Neuropathic pain (NP) is one of the most common complications after spinal cord injury (SCI), but no protein biomarkers has ever been introduced into clinical diagnosis. Previous studies implicated that toll-like receptor (TLR) 4 played a critical role in the development of NP in animal SCI models. Here, a total of 140 participants were recruited, 70 of them were SCI-NP subject and the rest 70 controls did not show neuropathic symptoms. TLR4 was upregulated significantly in SCI-NP patients compared with SCI-noNP subjects. Furthermore, we measured the concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), two TLR4 downstream pro-inflammatory cytokines, to assess their diagnostic values. Receiver operating characteristics (ROC) analysis revealed that TNF-α had great potential advantages to predict the progression of neuropathy, the risks of NP were strongly increased in SCI subjects with higher levels of TNF-α (odds ratio: 4.92; 95% confidence interval: 1.89-12.32). These results suggested neuro-immune activation contributed to the development of neuropathic disorder after SCI, and TNF-α could be a potential sensitive diagnostic biomarker for chronic neuropathic pain in SCI patients.

Modification of human BMSC with nanoparticles of polymeric biomaterials and plasmid DNA for BMP-2 secretion

BACKGROUND Genetic modification of human bone marrow stem cells (hBMSCs) before administration to a patient is emerging as a viable approach to creating tailored cells that perform effectively in a clinical setting. To this end, safe delivery systems are needed that can package therapeutic genes into nanoparticles for cellular delivery. METHODS We evaluated different plasmids on gene expression and compared the effective plasmids directly in hBMSCs. Then, we evaluated the transfection efficiencies of the polymeric carriers linoleic acid-substituted polyethylenimine (PEI-LA), polyethylenimine (PEI)-25, and PEI-2 using flow cytometry. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to compare the toxicity of PEI-LA and PEI-25 on hBMSCs. We further assessed bone morphogenetic protein-2 (BMP-2) secretion and the osteogenic activity of hBMSCs transfected with the polymeric (PEI-LA and PEI-25) gWIZ-BMP-2 complex. RESULTS Unlike the transformed cells that gave robust (>50%) transfection, only a few percent (<10%) of hBMSCs was transfected by the developed nanoparticles in culture. The plasmid DNA design was critical for expression of the transgene product, with the choice of the right promoter clearly enhancing the efficiency of transgene expression. Using the in-house designed PEI-LA, hBMSCs secreted BMP-2 in culture (~4 ng BMP-2/10(6) cells/d), which indicates the feasibility of using PEI-LA as a delivery system. Furthermore, we demonstrated an increased osteogenic activity in vitro for hBMSCs transfected with the PEI-LA containing the BMP-2 expression system. CONCLUSIONS These results provide encouraging evidence for the potential use of a low toxic PEI-LA to genetically modify hBMSC.

BMP7 enhances the effect of BMSCs on extracellular matrix remodeling in a rabbit model of intervertebral disc degeneration.

Intervertebral discs (IVDs) provide stability and flexibility to the spinal column; however, IVDs, and in particular the nucleus pulposus (NP), undergo a degenerative process characterized by changes in the disc extracellular matrix (ECM), decreased cell viability, and reduced synthesis of proteoglycan and type II collagen. Here, we investigated the efficacy and feasibility of stem cell therapy using bone marrow mesenchymal stem cells (BMSCs) over‐expressing bone morphogenetic protein 7 (BMP7) to promote ECM remodeling of degenerated IVDs. Lentivirus‐mediated BMP7 over‐expression induced differentiation of BMSCs into an NP phenotype, as indicated by expression of the NP markers collagen type II, aggrecan, SOX9 and keratins 8 and 19, increased the content of glycosaminoglycan, and up‐regulated β‐1,3‐glucuronosyl transferase 1, a regulator of chondroitin sulfate synthesis in NP cells. These effects were suppressed by Smad1 silencing, indicating that the effect of BMP7 on ECM remodeling was mediated by the Smad pathway. In vivo analysis in a rabbit model of disc degeneration showed that implantation of BMSCs over‐expressing BMP7 promoted cell differentiation and proliferation in the NP, as well as their own survival, and these effects were mediated by the Smad pathway. The results of the present study indicate the beneficial effects of BMP7 on restoring ECM homeostasis in NP cells, and suggest potential strategies for improving cell therapy for the treatment of disc diseases.

Synovial fibroblast-targeting liposomes encapsulating an NF-κB-blocking peptide ameliorates zymosan-induced synovial inflammation

Synovial fibroblasts (SFs) play a crucial role in the inflammatory process of rheumatoid arthritis (RA). The highly activated NF‐κB signal in SFs is responsible for most of the synovial inflammation associated with this disease. In this study, we have developed an SF‐targeting liposomal system that encapsulates the NF‐κB‐blocking peptide (NBD peptide) HAP‐lipo/NBD. HAP‐lipo/NBDs demonstrated efficient SF‐specific targeting in vitro and in vivo. Our study also showed a significant inhibitory effect of HAP‐lipo/NBD on NF‐κB activation, inflammatory cytokine release and SF migration capability after zymosan stimulation. Furthermore, the systemic administration of HAP‐lipo/NBDs significantly inhibited synovial inflammation and improved the pathological scores of arthritis induced by zymosan. Thus, these results suggest that an SF‐targeting NF‐κB‐blocking strategy is a potential approach for the development of alternative, targeted anti‐RA therapies.

Enhanced expression of neurotrophic factors in the injured spinal cord through vaccination with myelin basic protein-derived peptide pulsed dendritic cells.

Study Design. Vaccination of spinal cord injury (SCI) mice with myelin basic protein-derived peptide (A91) pulsed dendritic cells (DC) to enhance brain-derived neurotrophic factor and neurotrophin-3 (NT-3) expression in injured spinal cord. Objective. To investigate the effect of A91-pulsed DC (A91-DC) on expression of neurotrophic factor in injured spinal cord. Summary of Background Data. SCI leads to progressive secondary tissue degeneration, and no satisfactory treatment is currently available. Accumulating evidence indicates that administration of neurotrophic factors to injured spinal cord is partially successful at promoting nerve tissue repair. However, most of strategy can cause secondary injury and limiting their wide clinical application. Methods. Proliferation of T cells and the capability of CD4+ T cells to secret neurotrophic factors were first measured in vitro to demonstrate the stimulus action of the A91-DC. In SCI mice model, enzyme-linked immunosorbent assay and immunofluorescence was employed to investigate the brain-derived neurotrophic factor and NT-3 expression in injured spinal cord. Furthermore, the neuroprotective effect of A91-DC in injured spinal cord was examined through histology measurement. Results. In this study, we demonstrated that A91-DC promoted the capability of T cells to secret neurotrophic factors and in the subacute phase of SCI. Moreover, vaccination with A91-DC enhanced the expression level of brain-derived neurotrophic factor and NT-3 and exerted neuroprotective effect in injured spinal cord. Conclusion. The findings of study demonstrate that the therapeutic strategy of vaccination A91-DC is a potential minimally invasive approach that could provide strong neurotrophic factor support after SCI. Level of Evidence:

Assessment of the degradation rates and effectiveness of different coated Mg-Zn-Ca alloy scaffolds for in vivo repair of critical-size bone defects

Surgical repair of bone defects remains challenging, and the search for alternative procedures is ongoing. Devices made of Mg for bone repair have received much attention owing to their good biocompatibility and mechanical properties. We developed a new type of scaffold made of a Mg-Zn-Ca alloy with a shape that mimics cortical bone and can be filled with morselized bone. We evaluated its durability and efficacy in a rabbit ulna-defect model. Three types of scaffold-surface coating were evaluated: group A, no coating; group B, a 10-μm microarc oxidation coating; group C, a hydrothermal duplex composite coating; and group D, an empty-defect control. X-ray and micro-computed tomography(micro-CT) images were acquired over 12 weeks to assess ulnar repair. A mechanical stress test indicated that bone repair within each group improved significantly over time (P < 0.01). The degradation behavior of the different scaffolds was assessed by micro-CT and quantified according to the amount of hydrogen gas generated; these measurements indicated that the group C scaffold better resisted corrosion than did the other scaffold types (P < 0.05). Calcein fluorescence and histology revealed that greater mineral densities and better bone responses were achieved for groups B and C than for group A, with group C providing the best response. In conclusion, our Mg-Zn-Ca-alloy scaffold effectively aided bone repair. The group C scaffold exhibited the best corrosion resistance and osteogenesis properties, making it a candidate scaffold for repair of bone defects.

Investigations of silk fiber/calcium phosphate cement biocomposite for radial bone defect repair in rabbits

BackgroundThis study aimed to investigate the effects of silk fiber (SF)/calcium phosphate cement (CPC) biocomposite on repairing radial bone defects in rabbits.MethodsFour-month-old New Zealand rabbits were selected to create a bilateral radial bone defect model and divided into four groups according to implanted material: SF/CPC, SF/CPC/particulate bone (PB), PB, and control (C). The specimens were removed at four and eight postoperative weeks for general observation, X-ray examination, tissue slicing, scanning electron microscopy (SEM), and biomechanical testing.ResultsPostoperative X-ray showed no bone defect repair in group C and different degrees of bone defect repair in the other three groups. Imaging, histology, and SEM showed the following: group SF/CPC formed fine trabecular bone in week 4, while the maximum bending load in group SF/CPC in week 4 was significantly different from those in the other groups (P < 0.05).ConclusionsSF/CPC has good biocompatibility and bone-inducing ability, demonstrating its bone defect-repairing ability.