Biocompatibility and osteogenic potential of choline phosphate chitosan-coated biodegradable Zn1Mg.

Zinc alloys have demonstrated considerable potentials as implant materials for biodegradable vascular and orthopedic applications. However, the high initial release of Zn2+ can trigger intense immune responses that impede tissue healing. To address this challenge and enhance the osteogenic capacity of zinc alloys, the surface of Zn1Mg was subjected to CO2 plasma modification (Zn1Mg-PP) followed by grafting with choline phosphate chitosan (Zn1Mg-PP-PCCs). This study aims to investigate the in vitro and in vivo biocompatibility of the surface-modified Zn1Mg. The effect of the surface modification on the inflammatory response and osteogenic repair process was investigated. Compared with unmodified Zn1Mg, the degradation rate of Zn1Mg-PP-PCCs was significantly decreased, avoiding the cytotoxicity triggered by the release of large amounts of Zn2+. Moreover, PCCs significantly enhanced the cell-material adhesion, promoted the proliferation of osteoblasts (MC3T3-E1) and upregulated the expression of key osteogenic factors in vitro. Notably, the in vivo experiments revealed that the surface modification of Zn1Mg suppressed inhibited the expression of inflammatory cytokines, promoting the secretion of anti-inflammatory factors, thereby reducing inflammation and promoting bone tissue repair. Furthermore, histological analysis of tissue sections exhibited strong integration between the material and the bone, along with well-defined new bone formation and reduced osteoclast aggregation on the surface. This was attributed to the improved immune microenvironment by PCCs, which promoted osteogenic differentiation of osteoblasts. These findings highlight that the preparation of PCCs coatings on zinc alloy surfaces effectively inhibited ion release and modulated the immune environment to promote bone tissue repair. STATEMENT OF SIGNIFICANCE: Surface modification of biodegradable Zn alloys facilitates the suppression of intense immune responses caused by excessive ion release concentrations from implants. We modified the surface of Zn1Mg with choline phosphate chitosan (PCCs) and investigated the effects of surface modification on the inflammatory response and osteogenic repair process. In vitro results showed that the PCCs coating effectively reduced the degradation rate of Zn1Mg to avoid cytotoxicity caused by high Zn2+ concentration, favoring the proliferation of osteoblasts. In addition, in vivo results indicated that Zn1Mg-PP-PCCs attenuated inflammation to promote bone repair by modulating the release of inflammation-related factors. The surface-modified Zn1Mg implants demonstrated strong osseointegration, indicating that the PCCs coating effectively modulated the immune microenvironment and promoted bone healing.

Effects of Zr Addition on the Microstructural Evolution, Mechanical Properties, and Corrosion Behavior of Novel Biomedical Ti-Zr-Mo-Mn Alloys.

ß-Type Ti alloys have been widely investigated as implant materials owing to their excellent mechanical properties, corrosion resistance, and biocompatibility. In the present work, the effects of Zr on the microstructure, mechanical properties, and corrosion behaviors of Ti-Zr-Mo-Mn alloys were systematically studied. With the increase of Zr content, the phase composition gradually changed from intragranular-α + ß of (TZ)5:1MM alloy to grain-boundary-α + ß of (TZ)2:1MM alloy and finally transferred to a single ß phase structure of (TZ)1:1MM alloy. The (TZ)1:1MM alloy exhibited a good mechanical combination with a yield strength of 750.8 MPa, an elastic modulus of 61.3 GPa, and a tensile ductility of 14.6%. Moreover, the addition of Zr can effectively stabilize the passivation film and reduce the sensitivity of microgalvanic corrosion in simulated body fluid, leading to enhanced corrosion resistance in the TZMM alloys. X-ray photoelectron spectroscopy analysis together with the ion-sputtering technique revealed that the passivation films formed on TZMM alloys possessed a bilayered structure (outer Ti+Zr mixed-oxide layer and inner Zr-oxide-rich layer), in which the inner Zr oxide layer plays an important role in the corrosion resistance of the TZMM alloys. In vitro biocompatibility evaluations demonstrated that the TZMM alloys can support cell adhesion and proliferation with high biocompatibility comparable to that of CP-Ti, while in vivo biocompatibility evaluations validated the bone osteointegration ability of TZMM alloys after long-term implantation. The above results indicate that novel TZMM alloys are promising candidates for implant material.

Novel biomimetic mesoporous silica nanoparticle system possessing targetability and immune synergy facilitates effective solid tumor immuno-chemotherapy.

New strategies that enhance both the targetability of chemotherapy drugs and the synergistic effects of chemotherapy and immunotherapy are urgently needed for efficacious solid tumor therapy. In this study, a novel biomimetic nanoparticle system possessing the properties of tumor targeting and immune synergy was designed to meet these requirements. Mesoporous silica nanoparticles loaded with the chemotherapeutic drug doxorubicin (DOX) were coated with cell membranes modified by glycosylphosphatidylinositol (GPI)-anchored anti-HER2 single chain variable fragment (scFv) and the GPI-anchored co-stimulatory molecule CD80 (to promote solid tumor-targeted chemotherapy and cooperated immunotherapy, respectively). The impact of the nanotherapeutic system on both tumor-targeted chemotherapy and cellular immune response was investigated through in vitro and in vivo experiments. The results show that the novel biomimetic therapeutic system effectively promoted antitumor efficiency in vitro and in vivo. In addition, this therapeutic system further enhanced antitumor capacity by increasing CD8+ T cell activation and cytokine production and reducing myeloid-derived suppressor cell (MDSC) levels in tumors.

Cervical subtotal discectomy prosthesis validated in non-human primate model: A novel artificial cervical disc replacement concept?

Objective: To evaluate the biological function of cervical subtotal discectomy prosthesis (CSDP) implantation in a non-human primate model. Methods: A CSDP was tested for cytocompatibility and osseointegration capacity before implantation in non-human primates. Subsequently, the CSDP was improved based on three-dimensional CT measurements of the non-human primate cervical spine. Eight cynomolgus monkeys were selected for removal of the intervertebral disc and lower endplate of the C5/6 segment to complete the model construction for CSDP implantation. In 18-month follow-up, physiological indices, radiology, and kinematics were assessed to estimate the biological function of the CSDP in non-human primates, including biosafety, osseointegration, and biomechanics. Results: Co-cultured with the CSDP constituent titanium alloy (Ti6Al4V-AO), the mouse embryo osteoblast precursor cell MC3T3-E1 obtained extended adhesion, remarkable viability status, and cell proliferation. After implantation in the mouse femur for 28 days, the surface of Ti6Al4V-AO was covered by a large amount of new cancellous bone, which formed further connections with the femur cortical bone, and no toxicity was detected by blood physiology indices or histopathology. After completing implantation in primate models, no infection or osteolysis was observed, nor was any subsidence or displacement of the CSDP observed in CT scans in the 18-month follow-up. In particular, the interior of the cervical vertebra fixation structure was gradually filled with new trabecular bone, and the CSDP had achieved fixation and bony fusion in the vertebral body at 1 year post-operation. Meanwhile, no signs of inflammation, spinal cord compression, adjacent segment degeneration, or force line changes were observed in subsequent MRI observations. Moreover, there were no pathological changes of the joint trajectory, joint motion range, stride length, or the stance phase ratio revealed in the kinematics analysis at 3, 6, 12, or 18 months after CSDP implantation. Conclusion: We successfully designed a new cervical subtotal discectomy prosthesis and constructed an excellent non-human primate implantation model for the evaluation of subtotal disc replacement arthroplasty. Furthermore, we demonstrated that CSDP had outstanding safety, osseointegration capacity, and biomechanical stability in a non-human primate model, which might be a new choice in the treatment of cervical disc diseases and potentially change future outcomes of degenerative cervical diseases.

Spinal cord injury target-immunotherapy with TNF-α autoregulated and feedback-controlled human umbilical cord mesenchymal stem cell derived exosomes remodelled by CRISPR/Cas9 plasmid.

Human umbilical cord mesenchymal stem cell (hucMSC) derived exosomes (EXOs) have been investigated as a new treatment for spinal cord injury (SCI) because of their anti-inflammatory, anti-apoptotic, angiogenesis-promoting, and axonal regeneration properties. The CAQK peptide found in the brains of mice and humans after trauma has recently been found to specifically bind to the injured site after SCI. Thus, we developed a nanocarrier system called EXO-C@P based on hucMSC exosomes remodelled by the CRISPR/Cas9 plasmid to control inflammation and modified by the CAQK peptide. EXO-C@P was shown to effectively accumulate at the injury site and saturate the macrophages to significantly reduce the expression of inflammatory cytokines in a mouse model of SCI. Moreover, EXO-C@P treatment improved the performance of mice in behavioural assessments and upregulated soluble tumour necrosis factor receptor-1 (sTNFR1) in serum and at the trauma site after SCI surgery, but lowered the proportion of iNOS+ cells and the concentration of proinflammatory factors. In conclusion, EXO-C@P provides an effective alternative to multiple topical administration and drug delivery approaches for the treatment of SCI. STATEMENT OF SIGNIFICANCE: SCI is a serious disease characterised by a high incidence, high disability rate, and high medical costs, and has become a global medical problem. Several studies have shown that the inflammatory response is the critical inducer of secondary injury after SCI. The inflammatory cytokine TNF-α is considered to be one of the most significant therapeutic targets for autoimmune diseases. Antibodies targeting TNF-α and sTNFR1 are capable of neutralising free TNF-α. In this study, exosomes in the CRISPR/Cas9 system were used to establish stem cells with an autoregulated and feedback-controlled TNF-α response, with these cells secreting sTNFR1, which neutralised TNF-α and antagonised the inflammation stimulated by TNF-α. Moreover, the plasmid was combined with CAQK, which targeted the injury site and promoted the recovery of SCI function.

Laminoplasty versus laminectomy with fusion for treatment of multilevel cervical compressive myelopathy: an updated meta-analysis.

BACKGROUND: Multilevel cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) are debilitating degenerative diseases. If conservative treatment is ineffective, surgical options for multilevel CSM and OPLL include laminoplasty (LP) and laminectomy with fusion (LF). In this updated meta-analysis, we aimed to compare the clinical outcomes and complications of both approaches. METHODS: We searched PubMed, the Cochrane Library and Embase datasets from their inception to 31 March 2020, to identify all eligible studies comparing LP versus LF for multilevel CSM and OPLL. Data were extracted according to predefined endpoints. We summarised data by the random-effects or fixed-effect models, as necessary. RESULTS: Of 533 eligible studies, 16 were identified, which included 638 patients who underwent LP and 671 patients who underwent LF. No significant differences were observed between preoperative and postoperative scores of the Japanese Orthopaedic Association (p=1.0 and 0.20, respectively); Visual Analogue Scale (p=0.24 and 0.89, respectively); sagittal vertical axis ((p=0.16 and 0.87, respectively); Nurick Scale (p=0.59 and 0.17, respectively); and range of motion (p=0.67 and 0.63, respectively). However, total complications were higher for LF compared with LP (p=0.006). A significantly higher incidence of C5 palsy was observed in the LF group (p=0.004). The postoperative Neck Disability Index (NDI) was also higher in the LF group (p<0.001). CONCLUSIONS: Although LP and LF shared similar clinical improvement, LP had fewer complications, a lower incidence of C5 palsy, and better NDI scores and recovery outcomes than LF. Randomised studies are warranted to validate these findings.

Biomechanical Analysis of Cervical Artificial Disc Replacement Using Cervical Subtotal Discectomy Prosthesis.

Background: Anterior cervical discectomy and fusion (ACDF) sacrifices segmental mobility, which can lead to the acceleration of adjacent segment degeneration. The challenge has promoted cervical artificial disc replacement (CADR) as a substitute for ACDF. However, CADR has revealed a series of new issues that are not found in ACDF, such as hypermobility, subsidence, and wear phenomenon. This study designed a cervical subtotal discectomy prosthesis (CSDP) consisting of a cervical disc prosthesis structure (CDP structure), cervical vertebra fixation structure (CVF structure), link structure, and locking screw, aiming to facilitate motion control and reduce subsidence. The aim of this study was to assess the biomechanics of the CSDP using finite element (FE) analysis, friction-wear test, and non-human primates implantation study. Study Design: For the FE analysis, based on an intact FE C2-C7 spinal model, a CSDP was implanted at C5-C6 to establish the CSDP FE model and compare it with the Prestige LP prosthesis (Medtronic Sofamor Danek, Minneapolis, MN, United States). The range of motion (ROM), bone-implant interface stress, and facet joint force were calculated under flexion extension, lateral bending, and axial rotation. In addition, CSDP was elevated 1 mm to mimic an improper implantation technique to analyze the biomechanics of CSDP errors in the FE model. Moreover, the friction-wear test was conducted in vitro to research CSDP durability and observe surface wear morphology and total wear volume. Finally, the CSDP was implanted into non-human primates, and its properties were evaluated and verified by radiology. Results: In the FE analysis, the ROM of the CSDP FE model was close to that of the intact FE model in the operative and adjacent segments. In the operative segment, the CSDP error FE model increased ROM in flexion extension, lateral bending, and axial rotation. The maximum stress in the CSDP FE model was similar to that of the intact FE model and was located in the peripheral cortical bone region. The facet joint force changes were minimal in extension, lateral bending, and axial rotation loads in CSDP. In the friction-wear test, after the 150-W movement simulation, both the CVF-link-junction and the CDP-link-junction had slight wear. In the CSDP non-human primate implantation study, no subsidence, dislocation, or loosening was observed. Conclusion: In the FE analysis, the biomechanical parameters of the CSDP FE model were relatively close to those of the intact FE model when compared with the Prestige LP FE model. In terms of CSDP error FE models, we demonstrated that the implantation position influences CSDP performance, such as ROM, bone-implant interface stress, and facet joint force. In addition, we performed a friction-wear test on the CSDP to prove its durability. Finally, CSDP studies with non-human primates have shown that the CSDP is effective.

The Role of Gamma-Delta T Cells in Diseases of the Central Nervous System.

Gamma-delta (γδ) T cells are a subset of T cells that promote the inflammatory responses of lymphoid and myeloid lineages, and are especially vital to the initial inflammatory and immune responses. Given the capability to connect crux inflammations of adaptive and innate immunity, γδ T cells are responsive to multiple molecular cues and can acquire the capacity to induce various cytokines, such as GM-CSF, IL-4, IL-17, IL-21, IL-22, and IFN-γ. Nevertheless, the exact mechanisms responsible for γδ T cell proinflammatory functions remain poorly understood, particularly in the context of the central nervous system (CNS) diseases. CNS disease, usually leading to irreversible cognitive and physical disability, is becoming a worldwide public health problem. Here, we offer a review of the neuro-inflammatory and immune functions of γδ T cells, intending to understand their roles in CNS diseases, which may be crucial for the development of novel clinical applications.

The integration of pore size and porosity distribution on Ti-6A1-4V scaffolds by 3D printing in the modulation of osteo-differentation.

PURPOSE: In this study, pore size and porosity distribution of porous Ti-6Al-4V scaffolds (pTi) were controlled by 3D printing. The effects of pore size distribution at a constant porosity, or porosity distribution at a constant pore size pertaining to functions of adhesion, proliferation, and differentiation of the mouse embryonic osteoblast precursor (MC3T3-E1) cells were researched separately. METHODS: 3D printing was used to design five groups of pTi, designated as PS300/HP, PS300/LP, PS500/HP, PS500/LP, and PS800/HP based on pore size and porosity distribution. MC3T3-E1 cells were cultured on pTi, and non-porous Ti-6Al-4V samples (npTi) were prepared as control. The pTi was characterized with the scanning electron microscopy (SEM). MC3T3-E1 cells were stained via AlamarBlue assay and viability and proliferation analyzed. The mRNA levels of alkaline phosphatase (ALP), osteocalcin (OCN), collagentype-1 (Col-1), and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells were analyzed by real-time PCR analysis. RESULTS: The average pore size and porosity of pTi were recorded as (301 ± 9 µm, 58.8 ± 1.8%), (300 ± 9 µm, 43.4 ± 1.3%), (501 ± 11 µm, 58.3 ± 1.2%), (499 ± 12 µm, 42.7 ± 1.1%), and (804 ± 10 µm, 58.9 ± 1.3%), respectively. SEM images confirmed active attachment of cells and oriented with the direction of metal rod after pTi/MC3T3-E1 co-culture for 3 and 7 days. In addition, MC3T3-E1 cells grown on the PS800/HP displayed significantly higher proliferation compared with each group after 3 days incubation (p < 0.05). Moreover, cells showed some degree of proliferation in all groups, with the highest value recorded for PS800/HP after culture for 7 days (p < 0.05). The gene expression pattern of ALP, OCN, Col-1, and Runx2 confirmed that these were down-regulated when pore size increased or porosity decreased of pTi (p < 0.05). CONCLUSION: The pTi facilitated the adhesion and differentiation of osteoblast when pore size decreased or porosity increased. The scaffold model resembles physical modification with porous structures, which has potential application in the surface modifications of Ti implant.

Duration of electrochemical deposition affects the morphology of hydroxyapatite coatings on 3D-printed titanium scaffold as well as the functions of adhered MC3T3-E1 cells.

BACKGROUND: The use of 3D-printed scaffolds in repairing bone defects remains unexplored. We aimed to determine whether the duration of electrochemical deposition (ECD) affects the properties of hydroxyapatite (HA) coatings on 3D-printed titanium (TI) scaffolds as well as the corresponding phenotype of MC3T3-E1 cells seeded on these surfaces. METHODS: Five groups of HA-coated TI scaffolds were produced using different durations of ECD (0, 5, 10, 20, and 30 min) and examined under scanning electron microscopy (SEM). MC3T3-E1 cell adhesion to the HA-coated scaffolds and subsequent proliferation and viability were assessed using SEM, DAPI staining, EdU staining, and Alamar Blue assay, respectively. MC3T3-E1 cell expression of osteogenic genes was analyzed by fluorescence RT-PCR. RESULTS: On SEM, longer ECD durations resulted in more compact HA crystals of differing morphology coated onto the TI scaffolds. MC3T3-E1 cell adhesion differed among the five groups (p < 0.05), with the largest number of cells adhered to the scaffolds prepared with 30 min of ECD, followed by the group prepared with 20 min of ECD. However, the ECD duration of 20 min was associated with the highest cell viability and proliferation rate (both p < 0.05) as well as the highest mRNA expression levels of alkaline phosphatase, collagen I, osteocalcin and runt-related transcription factor 2 among the five groups (p < 0.05). CONCLUSIONS: In the fabrication of HA-coated 3D printed TI scaffolds, an ECD duration of 20 min resulted in scaffolds that best promoted MC3T3-E1 cell viability, proliferation and osteogenic gene expression.

Evaluation of cardiac function by pacing at different right ventricular sites in patients with third-degree atrioventricular block using Doppler ultrasound.

OBJECTIVE: This study utilized Doppler ultrasonography cardiograms in patients with third-degree atrioventricular (III-AV) block to compare right ventricular apex (RVA) pacing and right ventricular outflow tract (RVOT) pacing with respect to their effects on synchronization of contraction between the two ventricles, as well as on timing of specific left-ventricular electrical and mechanical events and their impact on left ventricular function. METHODS: Thirty-eight patients with (III-AV) block were implanted with dual-chamber pacemakers, in 20 cases, implantation occurring in the RVOT (RVOT group), while in 18 cases implantation occurred in the RVA (RVA group). Patients underwent Doppler echocardiography and electrocardiography (ECG) one month pre- and one month post-surgery, as well as 12 months post-surgical implantation of the pacemaker. RESULTS: Prior to pacemaker implantation, no significant differences were found between the two groups with respect to the following parameters: left ventricular end-diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), left ventricular ejection fraction (LVEF), E/A value (ratio of early [E] to late [A] ventricular filling velocities), inter-ventricular mechanical delay (IVMD)and septal-to-posterior wall motion delay (SPWMD). One month after implantation, no significant differences were found between the two groups for LVEDD, LVESD, LVEF, and E/A. However, compared with the RVOT group, the RVA group exhibited prolonged IVMD and SPWMD. Twelve months after pacemaker implantation, there was no significant difference for E/A between the two groups; however, compared with the ROVT group, the RVA group exhibited prolonged LVEDD, LVESD, IVMD, and SPWMD and significantly lower LVEF. CONCLUSION: Relative to RVA pacing, RVOT pacing mitigated impairment of systolic function and systolic dys-synchronization.

Echocardiography for determining the optimal atrioventricular interval in patients with dual chamber pacemakers.

BACKGROUND: We investigated the clinical value of Doppler echocardiography for determining the optimal setting of atrioventricular interval in patients with dual chamber pacemakers (DDD). In 38 patients with complete atrioventricular block and DDD pacemakers, the atrioventricular interval was prolonged in a stepwise fashion by 20 ms, from 90 to 250 ms, and cardiac stroke volume and transmitral flow were measured by pulsed Doppler echocardiography. METHODS: The optimal atrioventricular interval at which the cardiac stroke volume was maximal was 168.9 +/- 15.6 ms. The atrioventricular interval was 178.4 +/- 23.4 ms when the end of the A wave coincided with complete closure of the mitral valve. RESULTS: There was a significant linear relationship between the optimal atrioventricular interval and the predicted optimal atrioventricular interval (Y = 86.2 +/- 0.5X, r = 0.70, standard error of the estimate [SEE] = 11.5, P < 0.01). CONCLUSION: The optimal atrioventricular interval setting for DDD pacing can be successfully determined using Doppler echocardiography, which is a noninvasive, repeatable, and simple approach.

A Case of Cutaneous Metastasis from Urothelial Carcinoma of the Urinary Bladder / 대한피부과학회지

Cutaneous metastasis from bladder cancer is very rare. A 48-year-old man presented with a 5 month history of a dome-shaped nodule on his scalp. Histopathologic examination of the skin lesion revealed the proliferation of atypical cells, which were similar to those of urothelial carcinoma of the urinary bladder. We herein report on a case of cutaneous metastasis from urothelial carcinoma of the urinary bladder with a review of the Korean literature.

Two Cases of Eccrine Porocarcinoma / 대한피부과학회지

Eccrine porocarcinoma is a very rare, locally-aggressive, potentially fatal, malignant cutaneous neoplasm that arises from the intraepithelial ductal portion of the eccrine sweat gland. Eccrine porocarcinoma may develop either spontaneously or from a longstanding benign eccrine poroma. Herein, we describe two cases of eccrine porocarcinoma and review the related literature.

A Case of Xanthogranuloma on the Palm / 대한피부과학회지

Xanthogranuloma is a benign, fibrohistiocytic lesion that presents as a yellowish, cutaneous papule or nodule. Although the head, neck, and trunk are the most common sites for xanthogranuloma, it can appear at any site on the body. We report a rare solitary xanthogranuloma on the palm of 24-year-old man.