BACKGROUND:Gradient artificial bone repair scaffolds can mimic unique anatomical features in musculoskeletal tissues,showing great potential for repairing injured musculoskeletal tissues. OBJECTIVE:To review the latest research advances in gradient artificial bone repair scaffolds for tissue engineering in the musculoskeletal system and describe their advantages and fabrication strategies. METHODS:The first author of the article searched the Web of Science and PubMed databases for articles published from 2000 to 2023 with search terms"gradient,bone regeneration,scaffold".Finally,76 papers were analyzed and summarized after the screening. RESULTS AND CONCLUSION:(1)As an important means of efficient and high-quality repair of skeletal system tissues,gradient artificial bone repair scaffolds are currently designed bionically for the natural gradient characteristics of bone tissue,bone-cartilage,and tendon-bone tissue.These scaffolds can mimic the extracellular matrix of native tissues to a certain extent in terms of structure and composition,thus promoting cell adhesion,migration,proliferation,differentiation,and regenerative recovery of damaged tissues to their native state.(2)Advanced manufacturing technology provides more possibilities for gradient artificial bone repair scaffold preparation:Gradient electrospun fiber scaffolds constructed by spatially differentiated fiber arrangement and loading of biologically active substances have been developed;gradient 3D printed scaffolds fabricated by layered stacking,graded porosity,and bio-3D printing technology;gradient hydrogel scaffolds fabricated by in-situ layered injections,simple layer-by-layer stacking,and freeze-drying method;and in addition,there are also scaffolds made by other modalities or multi-method coupling.These scaffolds have demonstrated good biocompatibility in vitro experiments,were able to accelerate tissue regeneration in small animal tests,and were observed to have significantly improved histological structure.(3)The currently developed gradient artificial bone repair scaffolds have problems such as mismatch of gradient scales,unclear material-tissue interactions,and side effects caused by degradation products,which need to be further optimized by combining the strengths of related disciplines and clinical needs in the future.

OBJECTIVE: To review the research progress on the lower limb biomechanical characteristics of patients with discoid lateral meniscus (DLM) injury after surgery. METHODS: By searching relevant domestic and international research literature on DLM, the postoperative characteristics of knee joint movement biomechanics, tibiofemoral joint stress distribution, lower extremity force line, and patellofemoral joint changes in patients with DLM injury were summarized. RESULTS: Surgical treatment can lead to varying degrees of changes in the lower limb biomechanical characteristics of patients with DLM injury. Specifically, the kinematic biomechanics of the knee joint can significantly improve, but there are still problems such as extension deficits in the affected knee joint. The peak stress of the tibiofemoral joint decreases with the increase of the residual meniscus volume, and the degree of change is closely related to the residual meniscus volume. Preserving a larger volume of the meniscus, especially the anterior horn volume, helps to reduce stress concentration. The lower extremity force line will deviate outward after surgery, and the more meniscus is removed during surgery, the greater the change in the lower extremity force line after surgery. There are conditions such as cartilage degeneration, position and angle changes in the patellofemoral joint after surgery. CONCLUSION The changes in the lower limb biomechanical characteristics after DLM injury are closely related to the choice of surgical methods and rehabilitation programs. However, the mechanisms of biomechanical changes in multiple lower limb joints and individual differences still need to be further studied and clarified.
Humans ; Biomechanical Phenomena ; Tibial Meniscus Injuries/physiopathology* ; Menisci, Tibial/physiopathology* ; Knee Joint/surgery* ; Lower Extremity/physiopathology* ; Patellofemoral Joint/physiopathology* ; Range of Motion, Articular ; Knee Injuries/physiopathology*

OBJECTIVE: To explore the effect of bear bile powder (BBP) on acute lung injury (ALI) and the underlying mechanism. METHODS: The chemical constituents of BBP were analyzed by ultra-high-pressure liquid chromatography-mass spectrometry (UPLC-MS). After 7 days of adaptive feeding, 50 mice were randomly divided into 5 groups by a random number table (n=10): normal control (NC), lipopolysaccharide (LPS), dexamethasone (Dex), low-, and high-dose BBP groups. The dosing cycle was 9 days. On the 12th and 14th days, 20 µL of Staphylococcus aureus solution (bacterial concentration of 1 × 10^-7 CFU/mL) was given by nasal drip after 1 h of intragastric administration, and the mice in the NC group was given the same dose of phosphated buffered saline (PBS) solution. On the 16th day, after 1 h intragastric administration, 100 µL of LPS solution (1 mg/mL) was given by tracheal intubation, and the same dose of PBS solution was given to the NC group. Lung tissue was obtained to measure the myeloperoxidase (MPO) activity, the lung wet/dry weight ratio and expressions of CD14 and other related proteins. The lower lobe of the right lung was obtained for pathological examination. The concentrations of inflammatory cytokines including interleukin (IL)-6, tumour necrosis factor α (TNF-α ) and IL-1β in the bronchoalveolar lavage fluid (BALF) were detected by enzyme linked immunosorbent assay, and the number of neutrophils was counted. The colonic contents of the mice were analyzed by 16 sRNA technique and the contents of short-chain fatty acids (SCFAs) were measured by gas chromatograph-mass spectrometer (GC-MS). RESULTS: UPLC-MS revealed that the chemical components of BBP samples were mainly tauroursodeoxycholic acid and taurochenodeoxycholic acid sodium salt. BBP reduced the activity of MPO, concentrations of inflammatory cytokines, and inhibited the expression of CD14 protein, thus suppressing the activation of NF-κB pathway (P<0.05). The lung histopathological results indicated that BBP significantly reduced the degree of neutrophil infiltration, cell shedding, necrosis, and alveolar cavity depression. Moreover, BBP effectively regulated the composition of the intestinal microflora and increased the production of SCFAs, which contributed to its treatment effect (P<0.05). CONCLUSIONS BBP alleviates lung injury in ALI mouse through inhibiting activation of NF-κB pathway and decreasing expression of CD14 protein. BBP may promote recovery of ALI by improving the structure of intestinal flora and enhancing metabolic function of intestinal flora.
Animals ; Acute Lung Injury/pathology* ; Lipopolysaccharides ; Ursidae ; Gastrointestinal Microbiome/drug effects* ; Bile/chemistry* ; Lipopolysaccharide Receptors/metabolism* ; Powders ; Male ; Lung/drug effects* ; Mice ; Peroxidase/metabolism* ; Signal Transduction/drug effects* ; Cytokines/metabolism*

Inflammatory bowel disease (IBD) is an autoimmune disorder involving complex immune regulation, where balancing localized and systemic immunosuppression is a key challenge. This study aimed to enhance the therapeutic efficacy by engineering the probiotic Escherichia coli Nissle 1917 (EcN). We removed endogenous plasmids pMUT1 and pMUT2 from wild-type EcN and expressed the mPD-L1 (19‒238 aa)-mFc fusion protein on the bacterial surface using a cytolysin A (ClyA) fragment. This modification stabilized mPD-L1 (19‒238 aa) protein expression and promoted its recruitment to outer membrane vesicles (OMVs). The engineered strain, EcNΔ_pMUT1/2-ClyA-mPD-L1-mFc (EcN-ePD-L1-mFc), features conditional ePD-L1-mFc expression under the araBAD promoter, enhancing gut-targeted release and reducing systemic side effects. This strain improved treatment targeting and efficiency by enabling direct ePD-L1-mFc interaction with immune cells at inflammation sites. OMVs from this strain induced Treg proliferation, inhibited effector T cell proliferation in vitro, and significantly improved intestinal inflammation and colonic epithelial barrier repair in vivo. Additionally, the bacterium restored intestinal microbiota balance, increasing Lactobacillaceae and reducing Bacteroides. This study highlights the engineered bacterium's potential for targeted intestinal immune modulation and offers a novel local IBD treatment approach with promising clinical prospects.

Periodontal bone defects, primarily caused by periodontitis, are highly prevalent in clinical settings and manifest as bone fenestration, dehiscence, or attachment loss, presenting a significant challenge to oral health. In regenerative medicine, harnessing developmental principles for tissue repair offers promising therapeutic potential. Of particular interest is the condensation of progenitor cells, an essential event in organogenesis that has inspired clinically effective cell aggregation approaches in dental regeneration. However, the precise cellular coordination mechanisms during condensation and regeneration remain elusive. Here, taking the tooth as a model organ, we employed single-cell RNA sequencing to dissect the cellular composition and heterogeneity of human dental follicle and dental papilla, revealing a distinct Platelet-derived growth factor receptor alpha (PDGFRA) mesenchymal stem/stromal cell (MSC) population with remarkable odontogenic potential. Interestingly, a reciprocal paracrine interaction between PDGFRA⁺ dental follicle stem cells (DFSCs) and CD31⁺ Endomucin⁺ endothelial cells (ECs) was mediated by Vascular endothelial growth factor A (VEGFA) and Platelet-derived growth factor subunit BB (PDGFBB). This crosstalk not only maintains the functionality of PDGFRA⁺ DFSCs but also drives specialized angiogenesis. In vivo periodontal bone regeneration experiments further reveal that communication between PDGFRA⁺ DFSC aggregates and recipient ECs is essential for effective angiogenic-osteogenic coupling and rapid tissue repair. Collectively, our results unravel the importance of MSC-EC crosstalk mediated by the VEGFA and PDGFBB-PDGFRA reciprocal signaling in orchestrating angiogenesis and osteogenesis. These findings not only establish a framework for deciphering and promoting periodontal bone regeneration in potential clinical applications but also offer insights for future therapeutic strategies in dental or broader regenerative medicine.
Receptor, Platelet-Derived Growth Factor alpha/metabolism* ; Humans ; Neovascularization, Physiologic/physiology* ; Dental Sac/cytology* ; Single-Cell Analysis ; Transcriptome ; Mesenchymal Stem Cells/metabolism* ; Bone Regeneration ; Animals ; Dental Papilla/cytology* ; Periodontium/physiology* ; Stem Cells/metabolism* ; Regeneration ; Angiogenesis

Primary pulmonary nuclear protein of the testis (NUT) midline carcinoma (NMC) is a rare and highly aggressive thoracic malignancy that poses significant diagnostic and therapeutic challenges in clinical practice. This tumor is characterized by its heterogeneous clinical presentations and poor prognosis, often evading accurate initial diagnosis. In this study, we present two cases of primary pulmonary NMC treated with an integrated therapeutic approach combining anti-angiogenic agents, platinum-based chemotherapy, and radiotherapy. This multimodal strategy achieved survival durations of 32 and 13 months, respectively, surpassing the currently reported median survival of advanced NMC. Through a systematic literature review of reported cases, we have summarized the currently used diagnostic methods and treatment modalities for NMC. Our findings suggest that multimodal therapy incorporating anti-angiogenic treatment may offer superior clinical outcomes compared to conventional monotherapy regimens, particularly for patients who are not eligible for surgery. This comprehensive investigation enhances our understanding of NMC management by elucidating diagnostic pitfalls through histopathological correlation and proposing an effective therapeutic combination that demonstrates improved survival outcomes. By providing valuable insights into the diagnosis and treatment of primary pulmonary NMC, we hope to contribute to the development of more effective strategies for managing this rare and aggressive malignancy.
Humans ; Angiogenesis Inhibitors/therapeutic use* ; Carcinoma/therapy* ; Combined Modality Therapy ; Lung Neoplasms/diagnosis* ; Nuclear Proteins ; Oncogene Proteins ; Neoplasm Proteins

Nitroxide radicals are a kind of stable organic free radicals.Due to the presence of N-O·and unpaired electrons in its structure,it has many characteristics,and thus can be used as a spin marker to explore the mechanism of biological reactions;with its magnetic properties,it can be used for the development of multifunctional magnetic molecular materials and used as a polymerization inhibitor and catalyst in organic reactions.More importantly,it has a variety of biological activities such as anti-oxidation and anti-tumor,and so has attracted much attention in the research and development of new drugs.For example,the spin labeling of nitroxide radicals on anticancer drug podophyllotoxin can enhance the efficacy and reduce the toxicity,and can be easily to be absorbed by the body,thus obtaining a new anti-cancer drug 4-[4″-(2″,2″,6″,6″-tetramethyl-1″-piperidinyloxy nitroxide radical)amino]-4′-demethyl epipodophyllotoxin(GP-7).It is an effective way to seek new drugs by introducing pharmacophore to modify nitroxide radicals or it can be spin-labeled on active natural products to obtain new compounds with high efficiency and low toxicity.The research progress of derivatives and its biological activitives of nitroxide radicals are summarized,aiming to provide theoretical basis for the developing and utilizing of nitroxide radicals and searching for new drugs.

[Objective]Depression is a common mental illness with a profound impact on physical health.Depression has been associated with a higher risk of bacterial infection;however,whether this relationship is causal and how depression affects infection remains unclear.Therefore,we aimed to investigate the effects of depressive phenotype in infected mice by constructing a chronic unpredictable mild stress(CUMS)model.[Methods]Mice were induced with CUMS for 4 weeks.The depressive phenotype was evaluated using behavioral tests.Subsequently,the mice were intraperitoneally injected with Klebsiella pneumoniae to establish bacterial infection.Serum and abdominal tissues were collected 48 h after infection.Hematoxylin-eosin(HE)staining was used to observe the pathological changes in the tissues,and enzyme-linked immunosorbent assay(ELISA)was used to measure the levels of inflammatory factors.In addition,the fecal samples collected before infection were analyzed for 16S rDNA gene of gut microbiota,and the expression levels of NF-κB/NLRP3 signaling pathway in colon tissues of uninfected mice were detected.[Results]Behavioral tests showed that compared with the control mice,CUMS mice had significantly lower body weight(P<0.0001,t=5.426),lower sucrose preference rate(P<0.001,t=4.937),increased swimming stationary time(P<0.001,t=16.37),and decreased time spent in the central area of the open field(P<0.01,t=3.575).Survival analysis showed that compared with the control mice,the survival rate of CUMS mice significantly decreased after infection(P<0.05).Additionally,histochemical staining showed that tissue damage in the liver(P<0.05,t=4.025),kidney(P<0.05,t=2.828),and mesentery(P<0.01,t=5.367)significantly increased.Furthermore,ELISA results showed that the levels of the inflammatory cytokines IL-6(P<0.01,t=3.365),IL-1β(P<0.01,t=4.061),TNF-α(P<0.01,t=4.460)and LPS(P<0.0001,t=27.24)were elevated.The difference was statistically significant.According to 16S rDNA sequencing,CUMS-induced changes in the intestinal bacterial community structure of mice,making them significantly different from the control mice.Compared with the control mice,the expression levels of NF-κB(P<0.01,t=6.825)and NLRP3(P<0.001,t=9.561)were upregulated in CUMS mice.[Conclusion]The CUMS model was successfully constructed and CUMS mice developed more severe bacterial infection.Gut microbiota was dysregulated and the expression of NF-κB/NLRP3 signaling pathway was up-regulated in CUMS mice,which was related to the susceptibility to bacterial infection.