Lithium Promotes Osteogenesis via Rab11a-Facilitated Exosomal Wnt10a Secretion and ß-Catenin Signaling Activation.

Both bone mesenchymal stem cells (BMSCs) and their exosomes suggest promising therapeutic tools for bone regeneration. Lithium has been reported to regulate BMSC function and engineer exosomes to improve bone regeneration in patients with glucocorticoid-induced osteonecrosis of the femoral head. However, the mechanisms by which lithium promotes osteogenesis have not been elucidated. Here, we demonstrated that lithium promotes the osteogenesis of BMSCs via lithium-induced increases in the secretion of exosomal Wnt10a to activate Wnt/ß-catenin signaling, whose secretion is correlated with enhanced MARK2 activation to increase the trafficking of the Rab11a and Rab11FIP1 complexes together with exosomal Wnt10a to the plasma membrane. Then, we compared the proosteogenic effects of exosomes derived from lithium-treated or untreated BMSCs (Li-Exo or Con-Exo) both in vitro and in vivo. We found that, compared with Con-Exo, Li-Exo had superior abilities to promote the uptake and osteogenic differentiation of BMSCs. To optimize the in vivo application of these hydrogels, we fabricated Li-Exo-functionalized gelatin methacrylate (GelMA) hydrogels, which are more effective at promoting osteogenesis and bone repair than Con-Exo. Collectively, these findings demonstrate the mechanism by which lithium promotes osteogenesis and the great promise of lithium for engineering BMSCs and their exosomes for bone regeneration, warranting further exploration in clinical practice.

Effects of Different Oxidation Methods on the Wetting and Diffusion Characteristics of a High-Alumina Glass Sealant on 304 Stainless Steel.

Glass-to-metal seals are a very important element in the construction of vacuum tubes, electric discharge tubes, pressure-tight glass windows in metal cases, and metal or ceramic packages of electronic components. This paper presents the influence of different pretreatment methods on the high-temperature wettability of 304 stainless steel by high-alumina glass sealing. The pretreatment of the steel included laser surface melting and pre-oxidizing. The bonding characteristics of glass and stainless steel directly depend on the wettability in terms of the measured wetting angle, the type of oxide formed at the stainless steel surface, and the microstructural changes during the manufacturing process. The oxide film thickness on the stainless steel surface was evaluated to determine the optimal parameters. The film was wetted with high-alumina glass powder at different temperatures. The results showed that pre-oxidation decreased the wetting angle from 56.2° to 33.6°, while for the laser-melted surface, the wetting angle decreased from 49.8° to 31.5°. Scanning electron microscopy (SEM) revealed that the oxide film on the laser-melted surface was thicker and denser than that formed on the pre-oxidized surface. The present work shows that laser surface melting has a greater beneficial influence on the wetting and diffusion characteristics of 304 stainless steel sealed by high-alumina glass.

Engineered Exosome-Functionalized Extracellular Matrix-Mimicking Hydrogel for Promoting Bone Repair in Glucocorticoid-Induced Osteonecrosis of the Femoral Head.

Glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) is a serious bone disease that often affects young individuals. Bone grafting combined with core decompression is mainly used in the clinic to treat GC-ONFH. However, the outcome is usually not satisfactory, as expected. Here, we report an engineered exosome-functionalized extracellular matrix-mimicking hydrogel for promoting bone repair in GC-ONFH. Compared with Con-Exo, exosomes secreted by bone marrow stem cells (BMSCs) in conventional culture medium, the engineered Li-Exo, exosomes derived from bone marrow stem cells (BMSCs) stimulated by lithium ions, promoted macrophage M2 polarization while inhibiting macrophage M1 polarization. Furthermore, inspired by the fact that hydrogels can serve as desirable carriers of exosomes to facilitate their release in a sustained manner for improved therapeutic efficiency and in vivo application, an extracellular matrix (ECM)-mimicking hydrogel (Lightgel) composed of methacryloylated type I collagen was employed to incorporate Li-Exo/Con-Exo to construct the Lightgel-Li-Exo hydrogel/Lightgel-Con-Exo hydrogel. In vitro studies showed that the Lightgel-Li-Exo hydrogel had the most significant pro-osteogenic and pro-angiogenic activity. Finally, we evaluated the therapeutic effects of the hydrogel in rat models of GC-ONFH. As a result, the Lightgel-Li-Exo hydrogel had the most significant effect on enhancing macrophage M2 polarization, osteogenesis, and angiogenesis to promote bone repair in GC-ONFH. Taken together, this novel engineered exosome-functionalized ECM-mimicking hydrogel could be a promising strategy for osteonecrosis treatment.

Activated intestinal microbiome-associated tryptophan metabolism upregulates aryl hydrocarbon receptor to promote osteoarthritis in a rat model.

OBJECTIVE: To evaluate the role of aryl hydrocarbon receptor in the pathogenesis of osteoarthritis (OA) and its association with intestinal microbiome-related tryptophan metabolism. METHODS: Cartilage was isolated from OA patients undergoing total knee arthroplasty and analyzed for expression of aryl hydrocarbon receptor (AhR) and cytochrome P450 of family 1, subfamily A, and polypeptide 1 (CyP1A1). To gain mechanistic insights, OA model was induced in Sprague Dawley rats after antibiotic pretreatment combined with a tryptophan-rich diet (or not). The severity of OA was assessed eight weeks after surgery according to the Osteoarthritis Research Society International grading system. Expression of AhR, CyP1A1 as well as markers of bone and cartilage metabolism, inflammation, and intestinal microbiome-related tryptophan metabolism was assessed. RESULTS: Severity of OA in cartilage from patients positively correlated with expression of AhR and CyP1A1 in chondrocytes. In the rat model of OA, antibiotic pretreatment led to lower expression of AhR and CyP1A1 and lower serum levels of lipopolysaccharide (LPS). Conversely, antibiotics upregulated Col2A1 and SOX9 in cartilage, which mitigated the cartilage damage and synovitis, reduced the relative abundance of Lactobacillus. Additional tryptophan supplementation activated intestinal microbiome-related tryptophan metabolism, antagonizing the effects of antibiotics, exacerbating OA synovitis. CONCLUSION: Our study established an underlying intestinal microbiome associated tryptophan metabolism-OA connection which sets a new target for exploring OA pathogenesis. The alteration of tryptophan metabolism might prompt the activation and synthesis of AhR, accelerating the development of OA.

Does living at high altitude increase the risk of bleeding events after total knee arthroplasty? A retrospective cohort study.

OBJECTIVE: Post-operative bleeding after total knee arthroplasty (TKA) is a frequent cause of post-operative complications. This study compared blood loss and indicators of coagulation and fibrinolysis between TKA patients living at low or high altitudes. METHODS: We retrospectively analyzed 120 patients at our institution who underwent primary TKA from May 2019 to March 2020, and we divided them into those living in areas about 500 m or > 3000 m above sea level. We compared the primary outcome of total blood loss between them. We also compared them in terms of several secondary outcomes: coagulation and fibrinolysis parameters, platelet count, reduction in hemoglobin, hidden blood loss, intra-operative blood loss, transfusion rate, and incidence of thromboembolic events and other complications. RESULTS: Total blood loss was significantly higher in the high-altitude group than in the low-altitude group (mean, 748.2 mL [95% CI, 658.5-837.9] vs 556.6 mL [95% CI, 496.0-617.1]; p = 0.001). The high-altitude group also showed significantly longer activated partial thromboplastin time, prothrombin time, and thrombin time before surgery and on post-operative day one, as well as increased levels of fibrinogen/fibrin degradation product on post-operative days one and three. Ecchymosis was significantly more frequent in the high-altitude group (41.7 vs 21.7%; relative risk (RR) = 1.923 [95% CI, 1.091-3.389]; p = 0.019). The two groups showed similar transfusion rates, and none of the patients experienced venous thromboembolism, pulmonary embolism, or infection. CONCLUSION: High altitude may alter coagulation and fibrinolysis parameters in a way that increases risk of blood loss after TKA. Such patients may benefit from special management to avoid bleeding events.

[Research progress of immune cells regulating the occurrence and development of osteonecrosis of the femoral head].

Objective: To summarize the characteristics of the occurrence and development of osteonecrosis of the femoral head (ONFH), and to review the important regulatory role of immune cells in the progression of ONFH. Methods: The domestic and foreign literature on the immune regulation of ONFH was reviewed, and the relationship between immune cells and the occurrence and development of ONFH was analyzed. Results: The ONFH region has a chronic inflammatory reaction and an imbalance between osteoblast and osteoclast, while innate immune cells such as macrophages, neutrophils, dendritic cells, and immune effector cells such as T cells and B cells are closely related to the maintenance of bone homeostasis. Conclusion: Immunotherapy targeting the immune cells in the ONFH region and the key factors and proteins in their regulatory pathways may be a feasible method to delay the occurrence, development, and even reverse the pathology of ONFH.

Discovery of pyrrolo[2,3-d]pyrimidine-based molecules as a Wee1 inhibitor template.

In the past decade, Wee1 inhibition has received widespread attention as a cancer therapy. Our research aims to discover effective, selective and drug-like Wee1 inhibitors. Herein, a series of compounds with pyrrolo[2,3-d]pyrimidine-based heterocycles were designed, synthesized and confirmed to inhibit Wee1 kinase. The inhibitors afforded good potency in Wee1 Kinase inhibitory activity in enzymatic assays. These compounds showed strong proliferation inhibition against NCI-1299 cell lines and had acceptable pharmacokinetic properties. These derivatives are promising inhibitors that warrant further evaluation, towards the development of potential anticancer drug.

Primary cutaneous diffuse large B-cell lymphoma after total knee arthroplasty: a case study and a systematic review of its cutaneous manifestations and treatment options.

Introduction: Primary cutaneous diffuse large B-cell lymphoma (PCDLBCL) after total knee arthroplasty (TKA) is rare. Aim: The literature that analyses the cutaneous manifestations of PCDLBCL and assesses the effect and the outcome of treatment is scarce. Material and methods: We described a case of PCDLBCL after TKA, whose cutaneous mass develops around surgical sites, mimicking a prosthetic joint infection. In addition, we conducted a systematic review of 29 reported cases with PCDLBCL. Primary endpoint for the review was main cutaneous manifestations of PCDLBCL. Secondary endpoint included treatment options of PCDLBCL and optimal therapeutic method. Results: We found that the main cutaneous manifestations include infiltrative cutaneous lesions such as macules, papules or nodules, some of them presented as ulcerations or formation of vesicles, subcutaneous nodules or both. The treatment options include excision, radiotherapy, chemotherapy, and even "watchful waiting" as spontaneous regression was noted in some cases. Systemic chemotherapy is the most frequent initial treatment approach chosen, of which rituximab is often combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy and patients who received systemic rituximab tend to have a better overall survival (OS) time than those who did not. Conclusions: PCDLBCL is a rare disease after TKA, however, an early recognition and distinguishing from infection is still needed. Patients with PCDLBCL may profit from rituximab-based chemotherapy, increasing the survival rate, despite the high relapse rate and limited OS time in some cases.

S-adenosyl-L-homocysteine hydrolase FgSah1 is required for fungal development and virulence in Fusarium graminearum.

The S-adenosyl-L-homocysteine hydrolase (Sah1) plays a crucial role in methylation and lipid metabolism in yeast and mammals, yet its function remains elusive in filamentous fungi. In this study, we characterized Sah1 in the phytopathogenic fungus F. graminearum by generating knockout and knockout-complemented strains of FgSAH1. We found that the FgSah1-GFP fusion protein was localized to the cytoplasm, and that deletion of FgSAH1 resulted in defects in vegetative growth, asexual and sexual reproduction, stress responses, virulence, lipid metabolism, and tolerance against fungicides. Moreover, the accumulations of S-adenosyl-L-homocysteine (AdoHcy) and S-adenosyl-L-methionine (AdoMet) (the methyl group donor in most methyl transfer reactions) in ΔFgSah1 were seven- and ninefold higher than those in the wild-type strain, respectively. All of these defective phenotypes in ΔFgSah1 mutants were rescued by target gene complementation. Taken together, these results demonstrate that FgSah1 plays essential roles in methylation metabolism, fungal development, full virulence, multiple stress responses, lipid metabolism, and fungicide sensitivity in F. graminearum. To our knowledge, this is the first report on the systematic functional characterization of Sah1 in F. graminearum.