Dnmt3b ablation impairs fracture repair through upregulation of Notch pathway

We previously established that DNA methyltransferase 3b (Dnmt3b) is the sole Dnmt responsive to fracture repair and that Dnmt3b expression is induced in progenitor cells during fracture repair. In the current study, we confirmed that Dnmt3b ablation in mesenchymal progenitor cells (MPCs) resulted in impaired endochondral ossification, delayed fracture repair, and reduced mechanical strength of the newly formed bone in Prx1-Cre;Dnmt3bf/f (Dnmt3bPrx1) mice. Mechanistically, deletion of Dnmt3b in MPCs led to reduced chondrogenic and osteogenic differentiation in vitro. We further identified Rbpjκ as a downstream target of Dnmt3b in MPCs. In fact, we located 2 Dnmt3b binding sites in the murine proximal Rbpjκ promoter and gene body and confirmed Dnmt3b interaction with the 2 binding sites by ChIP assays. Luciferase assays showed functional utilization of the Dnmt3b binding sites in murine C3H10T1/2 cells. Importantly, we showed that the MPC differentiation defect observed in Dnmt3b deficiency cells was due to the upregulation of Rbpjκ, evident by restored MPC differentiation upon Rbpjκ inhibition. Consistent with in vitro findings, Rbpjκ blockage via dual antiplatelet therapy reversed the differentiation defect and accelerated fracture repair in Dnmt3bPrx1 mice. Collectively, our data suggest that Dnmt3b suppresses Notch signaling during MPC differentiation and is necessary for normal fracture repair

Antibacterial hemostatic dressings with nanoporous bioglass containing silver

Nanoporous bioglass containing silver (n-BGS) was fabricated using the sol-gel method, with cetyltrimethyl ammonium bromide as template. The results showed that n-BGS with nanoporous structure had a surface area of 467 m2/g and a pore size of around 6 nm, and exhibited a significantly higher water absorption rate compared with BGS without nanopores. The n-BGS containing small amounts of silver (Ag) had a slight effect on its surface area. The n-BGS containing 0.02 wt% Ag, without cytotoxicity, had a good antibacterial effect on Escherichia coli, and its antibacterial rate reached 99% in 12 hours. The n-BGS’s clotting ability significantly decreased prothrombin time (PT) and activated partial thromboplastin time (APTT), indicating n-BGS with a higher surface area could significantly promote blood clotting (by decreasing clotting time) compared with BGS without nanopores. Effective hemostasis was achieved in skin injury models, and bleeding time was reduced. It is suggested that n-BGS could be a good dressing, with antibacterial and hemostatic properties, which might shorten wound bleeding time and control hemorrhage

Case report: Thoracoscopic ablation for a patient with atrial fibrillation and persistent left superior vena cava

Persistent left superior vena cava (PLSVC) is a relatively rare congenital anomaly in the general population. It plays an important role in initiating and maintaining atrial fibrillation (AF) in some patients. Radiofrequency catheter ablation is the major treatment for patients with AF and PLSVC in most publications. Here, we reported a case of thoracoscopic ablation for a patient with atrial fibrillation and persistent left superior vena cava. After preprocedural simulation using virtual reality, we successfully completed box-lesion, ablation line from superior vena cava to inferior vena cava, left atrial appendage (LAA) excision, and PLSVC ablation. It provides a new perspective on surgical treatment for patients with AF and PLSVC

Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography

BackgroundAnomalous papillary muscle (APM) insertion into the mitral valve leaflet is rare but clinically important in hypertrophic obstructive cardiomyopathy (HOCM). In this study, we report the detection rate of APM insertion into the mitral valve using preoperative imaging modalities and the surgical outcomes of the patients.MethodsBy retrospectively reviewing the clinical records of patients with HOCM who underwent surgical treatment by a single operation group at our center from January 2020 to June 2023, patients with APM insertion into the mitral valve leaflet were identified. Baseline data, image characteristics, and surgical outcomes were analyzed.ResultsThe incidence of APM insertion into the mitral valve leaflet was 5.1% (8/157). The insertion site was located at A3 in six cases, which was more common than at A2 (n = 2). Preoperative echocardiography was used to identify two patients (25%) with APM insertion. We observed a particular echocardiographic feature for APM in HOCM patients, which was noted as a “lip nevus sign”, with a higher detection rate (62.5%). All patients successfully underwent septal myectomy with concomitant APM excision or mitral valve replacement via the transaortic (n = 5) or transmitral (n = 3) approach. The mean age was 49.0 ± 17.4 years and seven patients (87.5%) were female. Interventricular septum thickness (17.0 mm vs. 13.3 mm, P = 0.012) and left ventricular outflow gradient (117.5 mmHg vs. 7.5 mmHg, P = 0.012) were significantly decreased after surgery. Residual outflow obstruction, systolic anterior motion, and ≥3+ mitral regurgitation were negative. During the follow-up of 26.2 ± 12.2 months, there were no reported operations, adverse events, mitral regurgitation aggravations, recurrences of outflow obstruction, or instances of SAM.ConclusionsPapillary muscles inserted into the mitral valve leaflet are a subtype of subvalvular malformation in HOCM that requires surgical correction. The lip nevus sign on echocardiography is a characteristic of APM insertion in HOCM and may improve the preoperative detection rate. Adequate myectomy with anomalous papillary muscle excision has achieved good results in reducing the outflow gradient and eliminating mitral regurgitation, with good outcomes at short-to-intermediate follow-up

Urine Metabolomics Profiling of Lumbar Disc Herniation and its Traditional Chinese Medicine Subtypes in Patients Through Gas Chromatography Coupled With Mass Spectrometry

Lumbar disc herniation (LDH) possesses complex pathogenesis, which has not been well elucidated yet. To date, specific or early diagnosis of LDH remains unavailable, resulting in missed opportunity for effective treatment. According to Traditional Chinese medicine (TCM) theory, LDH can be divided into two subtypes (reality syndrome and deficiency syndrome). The purpose of this study was to analyze the metabolic disorders of LDH and its TCM subtypes and screen out potential biomarkers for LDH diagnosis. Gas chromatography coupled with mass spectrometry (GC-MS) was applied to test the urine samples from 66 participants (30 healthy volunteers, 18 LDH patients with deficiency syndrome and 18 patients with reality syndrome). PCA analysis showed a distinct separation tendency between the healthy subjects and LDH patients but no obvious separation between the different syndromes (reality syndrome and deficiency syndrome) of LDH patients. As a result, 23 metabolites were identified significantly altered in the LDH patients, as compared with the healthy subjects. The altered metabolites belong to amino acid metabolism, nucleic acid metabolism, carbohydrate metabolism, and vitamin metabolism, which are related to osteoporosis and inflammation. Our results indicate metabolic disorders of LDH and thereby propose a group of metabolic biomarkers for potential application in early diagnosis of LDH in clinic, which provide a reasonable explanation for the pathogenesis of LDH

Intra-Articular Injection of Fructus Ligustri Lucidi Extract Attenuates Pain Behavior and Cartilage Degeneration in Mono-Iodoacetate Induced Osteoarthritic Rats

Fructus Ligustri Lucidi (FLL) has been widely used as a traditional Chinese medicine (TCM) for treating soreness and weakness of waist and knees. It has potential for treating OA owing to its kidney-tonifying activity with bone-strengthening effects, but there is so far no report of its anti-OA effect. This study established a rat OA model by intra-articular (IA) injection of mono-iodoacetate (1.5 mg) and weekly treated by IA administration of FLL at 100 μg/mL for 4 weeks. Thermal withdrawal latency, mechanical withdrawal threshold, and spontaneous activity were tested for evaluation of pain behavior, and histopathological (HE, SO, and ABH staining) and immunohistochemical (Col2, Col10, and MMP13) analyses were conducted for observation of cartilage degradation. In vitro effect of FLL on chondrocytes was evaluated by MTT assay and qPCR analysis. Moreover, HPLC analysis was performed to determine its chemoprofile. The pain behavioral data showed that FLL attenuated joint pain hypersensitivity by increasing thresholds of mechanical allodynia and thermal hyperalgesia as well as spontaneous activity. The histopathological result showed that FLL reversed OA cartilage degradation by protecting chondrocytes and extracellular matrix in cartilage, and the immunohistochemical analysis revealed its molecular actions on protein expressions of MMP13, Col2, and Col10 in cartilage. The MTT assay showed its proliferative effects on chondrocytes, and qPCR assay clarified its mechanism associated with gene expressions of Mmp13, Col2, Col10, Adamts5, Aggrecan, and Runx2 in TNF-α treated chondrocytes. Our results revealed an anti-OA effect of FLL on pain behavior and cartilage degradation in OA rats and clarified a molecular mechanism in association with the suppression of chondrocyte hypertrophy and catabolism. IA FLL can be regarded as novel and promising option for OA therapy

Nanofat lysate ameliorates pain and cartilage degradation of osteoarthritis through activation of TGF-β–Smad2/3 signaling of chondrocytes

Introduction: Nanofat is an effective cell therapy for osteoarthritis (OA). However, it has clinical limitations due to its short half-life. We developed Nanofat lysate (NFL) to overcome the defect of Nanofat and explore its anti-OA efficacy and mechanism.Methods: Monoiodoacetate (MIA) was employed to establish rat OA model. For pain assessment, paw withdrawal latency (PWL) and thermal withdrawal latency (TWL) were evaluated. Degeneration of cartilage was observed by histopathological and immunohistochemical examination. Primary chondrocytes were treated with TNF-α to establish the cellular model of OA. MTT, wound healing, and transwell assays were performed to assess effects of NFL on chondrocytes. RNA-seq, qPCR and Western blot assays were conducted to clarify the mechanism of NFL.Results and Discussion: The animal data showed that PWL and TWL values, Mankin’s and OARSI scorings, and the Col2 expression in cartilage were significantly improved in the NFL-treated OA rats. The cellular data showed that NFL significantly improved the proliferation, wound healing, and migration of chondrocytes. The molecular data showed that NFL significantly restored the TNF-α-altered anabolic markers (Sox9, Col2 and ACAN) and catabolic markers (IL6 and Mmp13). The RNA-seq identified that TGF-β-Smad2/3 signaling pathway mediated the efficacy of NFL, which was verified by qPCR and Western blot that NFL significantly restored the abnormal expressions of TGFβR2, phosphorylated-Smad2, phosphorylated-Smad2/3, Col2, Mmp13 and Mmp3. After long-term storage, NFL exerted similar effects as its fresh type, indicating its advantage of storability. In sum, NFL was developed as a new therapeutic approach and its anti-OA efficacy and mechanism that mediated by TGF-β-Smad2/3 signaling was determined for the first time. Besides, the storability of NFL provided a substantial advantage than other living cell-based therapies