Qixin Zheng’s research while affiliated with Huazhong University of Science and Technology and other places

Bone regeneration requires the interaction of osteogenesis, osteolysis, and angiogenesis as well as an appropriate immune microenvironment. Recombinant human parathyroid hormone (PTH1-34) is approved for clinical anti-osteoporosis treatment because of its good osteogenic activity, osteoclastosis, and angiogenesis. However, the phenomenon of net bone resorption limits its use in local bone repair. Our group provides an effective strategy for multifunctional calcium phosphate (CaP) ceramics with modulating M1 macrophage pro-inflammatory effects, and bone regeneration. CaP ceramic scaffold is functionalized with parathyroid hormone related peptide-1 (PTHrP-1) for bone defect repair. First, peptide-functionalized true bone ceramic (TBC) scaffold exhibit limited M1 macrophage pro-inflammatory effects to improve the osteogenic microenvironment. Second, PTHrP-1 retains the osteogenic activity and angiogenic properties of PTH1-34 while downregulating osteoclast activity to induce favorable bone formation. Third, the peptide modified by tri-continuous aspartic acids (D3) and serine phosphorylation (PSer) has high affinity to the natural CaP matrix, achieving a slow release of PTHrP-1 in the TBC scaffold. Fourth, the carboxyl group of aspartate combined with calcium effectively promotes hydroxyapatite (HAP) nucleation and completes self-assembled mineralization. which is beneficial for bone regeneration. The results show that PTHrP-1-TBC is more suitable for bone regeneration than TBC scaffold and unmodified peptide alone.

Background Severe and complex cervical spondylotic myelopathy(CSM) requires surgical treatment. The common methods of posterior cervical spine surgery are laminoplasty and laminectomy with lateral mass screw internal fixation. However, the operative effect of this surgical approach is unclear owing to the complexity and severity of CSM in patients who undergo this surgical treatment.Therefore, we aimed to evaluate the clinical effects of posterior cervical laminectomy and lateral mass screw internal fixation in patients with severe and complex CSM. Methods We retrospectively analysed 60patients (48men,12women; mean age59.7 years) with severe and complex CSM who underwent posterior cervical laminectomy and lateral mass screw internal fixation from May 2013 to June 2020. Forty-eight patients underwent laminectomy and lateral mass screw internal fixation;12 patients underwent laminectomy and lateral mass screw internal fixation with 1–2 segmental laminoplasty. C-spine radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) were used to detect any curvature and fusion of the cervical spine, restenosis, and loose/broken internal fixation screws.Clinical efficacy was evaluated using Japanese Orthopaedic Association (JOA)scores, neck disability index(NDI), Odom’s classification, and the visual analogue scale(VAS) for pain. Results Overall effect was satisfactory at the last follow-up (average, 3.6 years [range, 6 months–6 years]), with no restenosis or loosened, slipped, or broken internal fixations. The anterior curvature angle of lordosis (n=46)was not significantly different from baseline at the last follow-up(P>0.05). The cervical kyphosis angle (n=14)was significantly improved at the last follow-up compared with the baseline value (P<0.05), as were the JOA, NDI, and VAS scores(all P<0.05). Odom’s classifications at the last follow-up were excellent, good, and fair in 45, 12, and three patients, respectively. Conclusions Posterior cervical laminectomy and lateral mass screw internal fixation achieved satisfactory clinical results in severe and complex CSM cases.Combining this surgical method with laminoplasty of 1–2 spinal segments stabilised the cervical spine and provided spinal decompression while preventing excessive backward drift of the cervical spinal cord, resulting in fewer complications.

Background:Severe and complex cervical spondylotic myelopathy(CSM) requires surgical treatment, usually laminoplasty or laminectomy with lateral mass screw internal fixation. However, the operative effects of these surgical approaches are unclear.Therefore, we aimed to evaluate the clinical effects of posterior cervical laminectomy and lateral mass screw internal fixation in patients with severe and complex CSM. Methods:We retrospectively analysed 60 patients with severe and complex CSM who underwent posterior cervical laminectomy and lateral mass screw internal fixation between May 2013 and June 2020. C-spine radiographs, computed tomography scans, and magnetic resonance images were used to detect curvature and fusion of the cervical spine, restenosis, and loose/broken internal fixation screws. Clinical efficacy was evaluated using Japanese Orthopaedic Association (JOA)scores, the neck disability index (NDI), Odom’s classification, and the visual analogue scale (VAS) for pain. Results: At the last follow-up, there was no restenosis or loosened/broken internal fixations. The anterior curvature angle of lordosis (n=46) at the last follow-up was not different from that at baseline (P>0.05). The cervical kyphosis angle (n=14) at the last follow-up was improved compared with that at baseline (P<0.05), as were the JOA, NDI, and VAS scores (all P<0.05). Odom’s classifications at the last follow-up were excellent, good, and fair in 45, 12, and 3patients, respectively. Conclusions: Posterior cervical laminectomy and lateral mass screw internal fixation achieved satisfactory clinical results in severe and complex CSM cases:the cervical spine was stabilised, achieving spinal decompression while preventing excessive backward drift of the cervical spinal cord.

Taxol has been clinically approved as an antitumor drug, and it exerts its antitumor effect through the excessive stabilization of microtubules in cancer cells. Recently, moderate microtubule stabilization by Taxol has been shown to efficiently promote neurite regeneration and functional recovery after spinal cord injury (SCI). However, the potential for the clinical translation of Taxol in treating SCI is limited by its side effects and low ability to cross the blood-spinal cord barrier (BSCB). Self-assembled peptide hydrogels have shown potential as drug carriers for the local delivery of therapeutic agents. We therefore hypothesized that the localized delivery of Taxol by a self-assembled peptide scaffold would promote axonal regeneration by stabilizing microtubules during the treatment of SCI. In the present study, the mechanistic functions of the Taxol-releasing system were clarified in vitro and in vivo using immunofluorescence labeling, histology and neurobehavioral analyses. Based on the findings from the in vitro study, Taxol released from a biological functionalized SAP nanofiber scaffold (FGLmx/Taxol) remained active and promoted neurite extension. In this study, we used a weight-drop contusion model to induce SCI at T9. The local delivery of Taxol from FGLmx/Taxol significantly decreased glial scarring and increased the number of nerve fibers compared with the use of FGLmx and 5% glucose. Furthermore, animals administered FGLmx/Taxol exhibited neurite preservation, smaller cavity dimensions, and decreased inflammation and demyelination. Thus, the local delivery of Taxol from FGLmx/Taxol was effective at promoting recovery after SCI and has potential as a new therapeutic strategy for SCI.

Osteogenesis, osteoclastogenesis, and angiogenesis are the most important processes in bone repair. Parathyroid hormone (PTH) has pro‐osteogenic, pro‐osteoclastogenic, and proangiogenic effects and may be a candidate for use in bone defect repair. However, the local application of PTH to bone defects is counterproductive due to its excessive osteoclastic and bone resorptive effects. In this study, a PTH derivative, PTHrP‐2, is developed that can be applied to local bone defects. First, a modified peptide with a calcium‐binding repeat glutamine tail undergoes controlled local release from a ceramic material and is shown to be a better fit for the repair process than the unmodified peptide. Second, the modified peptide is shown to have strong pro‐osteogenic activity due to mineralization and its facilitation of serine (Ser) phosphorylation. Third, the modified peptide is shown to maintain the pro‐osteoclastogenic and proangiogenic properties of the unmodified peptide, but its pro‐osteoclastogenic activity is reduced compared to that of the unmodified peptide. The reduced pro‐osteoclastogenic and increased pro‐osteogenic properties of the modified peptide reverse the imbalance between osteoblasts and osteoclasts with local PTH application and shift bone resorption to bone regeneration.

An ideal bone substitute should be biocompatible, biodegradable, osteoinductive and osteoconductive. In our previous work, we fabricated a three-dimensional porous scaffold based on mineralized recombinant human-like collagen, nano-hydroxyapatite/recombinant human-like collagen/poly(lactic acid) (nHA/RHLC/PLA). Like other HA/collagen scaffolds, the nHA/RHLC/PLA scaffold lacked osteoinductive bioactivity. The purpose of the present study was to develop a polydopamine (pDA)-assisted BMP-2-derived peptide (designated as P24) surface modification strategy for improving the osteogenesis of the nHA/RHLC/PLA scaffold. The immobilization efficiency and release kinetics of P24, and in vitro osteoinductive activity of the nHA/RHLC/PLA-pDA-P24 scaffold were examined. The in vivo osteoinductive activity of the scaffold was evaluated usinga rat criticalsize calvarial defect model. Our results showed that pDA-assisted surface modification could more efficiently mediate the immobilization of P24 peptide onto the scaffold surfaces than physical adsorption. The in vitro release study showed that the P24 peptide was released slowly and steadily from the nHA/RHLC/PLA-pDA-P24 scaffold in a sustained manner, with a short initial burst release only during the first day, while the physisorbed nHA/RHLC/PLA-P24 group showed a sharp burst P24 release followed by a plateau phase. In vitro osteogenesis assay, the ALP activitiy and mRNA expression of osteo-specific markers of rat-derived mesenchymal stem cells (rMSCs) in the nHA/RHLC/PLA-pDA-P24 group were significantly higher than those of the nHA/RHLC/PLA-P24 and non-P24-loaded nHA/RHLC/PLA groups. In vivo, three-dimensional CT evaluation and histological examination demonstrated the nHA/RHLC/PLA-pDA-P24 scaffolds significantly enhanced bone regeneration of rat cranial defects to a much greater extent than physisorbed nHA/RHLC/PLA-P24 and non-P24-loaded nHA/RHLC/PLA scaffolds. Our findings indicated that the pDA-assisted surface modification method could significantly improve the osteogenesis activity of the nHA/RHLC/PLA scaffold and the new nHA/RHLC/PLA-pDA-P24 scaffold was a promising scaffold biomaterial for bone tissue regeneration.

Raw data exported from the spectrophotometer, fluorescence microscopy, phase-contrast photomicrograph, flow cytometer BD FACSCalibur and Western blot applied for data analyses and preparation for Figs. 1–7

Background Iron overload is recognized as a new pathogenfor osteoporosis. Various studies demonstrated that iron overload could induce apoptosis in osteoblasts and osteoporosis in vivo. However, the exact molecular mechanisms involved in the iron overload-mediated induction of apoptosis in osteoblasts has not been explored. Purpose In this study, we attempted to determine whether the mitochondrial apoptotic pathway is involved in iron-induced osteoblastic cell death and to investigate the beneficial effect of N-acetyl-cysteine (NAC) in iron-induced cytotoxicity. Methods The MC3T3-E1 osteoblastic cell line was treated with various concentrations of ferric ion in the absence or presence of NAC, and intracellular iron, cell viability, reactive oxygen species, functionand morphology changes of mitochondria and mitochondrial apoptosis related key indicators were detected by commercial kits. In addition, to further explain potential mechanisms underlying iron overload-related osteoporosis, we also assessed cell viability, apoptosis, and osteogenic differentiation potential in bone marrow-derived mesenchymal stemcells(MSCs) by commercial kits. Results Ferric ion demonstrated concentration-dependent cytotoxic effects on osteoblasts. After incubation with iron, an elevation of intracelluar labile iron levels and a concomitant over-generation of reactive oxygen species (ROS) were detected by flow cytometry in osteoblasts. Nox4 (NADPH oxidase 4), an important ROS producer, was also evaluated by western blot. Apoptosis, which was evaluated by Annexin V/propidium iodide staining, Hoechst 33258 staining, and the activation of caspase-3, was detected after exposure to iron. Iron contributed to the permeabilizatio of mitochondria, leading to the release of cytochrome C (cyto C), which, in turn, induced mitochondrial apoptosis in osteoblasts via activation of Caspase-3, up-regulation of Bax, and down-regulation of Bcl-2. NAC could reverse iron-mediated mitochondrial dysfunction and blocked the apoptotic events through inhibit the generation of ROS. In addition, iron could significantly promote apoptosis and suppress osteogenic differentiation and mineralization in bone marrow-derived MSCs. Conclusions These findings firstly demonstrate that the mitochondrial apoptotic pathway involved in iron-induced osteoblast apoptosis. NAC could relieved the oxidative stress and shielded osteoblasts from apoptosis casused by iron-overload. We also reveal that iron overload in bone marrow-derived MSCs results in increased apoptosis and the impairment of osteogenesis and mineralization.

Effect of iron on the exprssion of DUOX1 and DUOX2 in osteoblasts (A-B) Representative western blot data for DUOX1 and DUOX2 in osteoblasts following exposure to FAC (0–200 µM) for 120 h. β-actin was used as an internal control. Date are presented as means ± SD, n = 3; ∗P < 0.05 vs. the control.

Cytotoxic effects of iron on the viability of osteoblasts Viability of osteoblasts was evaluated by CCK-8 assay after treatment with FAC (25–200 µM) for 24 h, 72 h and 120 h. Compared to the control (FAC 0 µM), iron significantly reduced cell viability in a dose-dependent manner after 120-h FAC treatment. The values are presented as means ± SD, n = 3; 793 ∗P < 0.05 vs. the control.