The Molecular Mechanism of ferroptosis and Its Relationship with Parkinson's Disease.

Neurodegenerative diseases such as Parkinson's disease (PD) have complex pathogenetic mechanisms. Genetic, age, and environmental factors are all related to PD. Due to the unclear pathogenesis of PD and the lack of effective cure methods, it is urgent to find new targets for treating PD patients. Ferroptosis is a form of cell death that is reliant on iron and exhibits distinct morphological and mechanistic characteristics compared to other types of cell death. It encompasses a range of biological processes, including iron/lipid metabolism and oxidative stress. In recent years, research has found that ferroptosis plays a crucial role in the pathophysiological processes of neurodegenerative diseases and stroke. Therefore, ferroptosis is also closely related to PD, This article reviews the core mechanisms of ferroptosis and elucidates the correlation between PD and ferroptosis. In addition, new compounds that have emerged in recent years to exert anti PD effects by inhibiting the ferroptosis signaling pathway were summarized. I hope to further elaborate the relationship between ferroptosis and PD through the review of this article, and provide new strategies for developing PD treatments targeting ferroptosis.

Endothelial Cells Promote Pseudo-islet Function Through BTC-EGFR-JAK/STAT Signaling Pathways.

Interactions between cells are of fundamental importance in affecting cell function. In vivo, endothelial cells and islet cells are close to each other, which makes endothelial cells essential for islet cell development and maintenance of islet cell function. We used endothelial cells to construct 3D pseudo-islets, which demonstrated better glucose regulation and greater insulin secretion compared to conventional pseudo-islets in both in vivo and in vitro trials. However, the underlying mechanism of how endothelial cells promote beta cell function localized within islets is still unknown. We performed transcriptomic sequencing, differential gene analysis, and enrichment analysis on two types of pseudo-islets to show that endothelial cells can promote the function of internal beta cells in pseudo-islets through the BTC-EGFR-JAK/STAT signaling pathway. Min6 cells secreted additional BTC after co-culture of endothelial cells with MIN6 cells outside the body. After BTC knockout in vitro, we found that beta cells functioned differently: insulin secretion levels decreased significantly, while the expression of key proteins in the EGFR-mediated JAK/STAT signaling pathway simultaneously decreased, further confirming our results. Through our experiments, we elucidate the molecular mechanisms by which endothelial cells maintain islet function in vitro, which provides a theoretical basis for the construction of pseudo-islets and islet cell transplants for the treatment of diabetes mellitus.

Plant-Derived Exosomes as Novel Nanotherapeutics Contrive Glycolysis Reprogramming-Mediated Angiogenesis for Diabetic Ulcer Healing.

Reversal of endothelial cell (EC) dysfunction under high-glucose (HG) conditions to achieve angiogenesis has remained a big challenge in diabetic ulcers. Herein, exosomes derived from medicinal plant ginseng (GExos) were shown as excellent nanotherapeutics with biomimetic cell membrane-like structures to be able to efficiently transfer the encapsulated active substances to ECs, resulting in a marked reprogramming of glycolysis by up-regulating anaerobic glycolysis and down-regulating oxidative stress, which further restore the proliferation, migration, and tubule formation abilities of ECs under HG conditions. In vivo, GExos enhance the angiogenesis and nascent vessel network reconstruction in full-thickness diabetic complicated skin ulcer wounds in mice with high biosafety. GExos were shown as promising nanotherapeutics in stimulating glycolysis reprogramming-mediated angiogenesis in diabetic ulcers, possessing wide application potential for reversing hyperglycemic dysangiogenesis and stimulating vascular regeneration.

Efficacy of tacrolimus monotherapy in primary membranous nephropathy.

Objective: The aim of this study was to observe the remission of primary membranous nephropathy (PMN) and evaluate the efficacy of tacrolimus (TAC) monotherapy for PMN in comparison with TAC combined with a low-dose glucocorticoid (GC) protocol (TAC + GC). Methods: This was tested in a prospective monocentric observational trial of 70 patients with PMN, of whom 34 received TAC (0.05-0.075 mg/kg/day) or 36 received TAC (0.05-0.075 mg/kg/day) and GC (0.3-0.5 mg/kg/day of prednisone). Results: At 3, 6, 9, and 12 months of treatment, the effective rates in the TAC group and the TAC + GC group were similar (P > 0.05). The urinary protein quantification was reduced in patients under both therapeutic protocols, and the differences in the proteinuria quantification at 3, 6, 9, and 12 months of treatment were not statistically significant between the two groups (P > 0.05). The overall incidence of adverse reactions in the TAC group was lower than that in the TAC + GC group (23.5% < 36.1%), and the difference was statistically significant (P < 0.05). Conclusion: TAC monotherapy for PMN could effectively reduce urinary protein quantification and increase serum albumin levels. Compared with TAC + GC, TAC monotherapy for PMN had no difference in efficacy and fewer incidences of adverse reactions.

Invasive assessment of coronary microvascular dysfunction and cardiovascular outcomes across the full spectrum of CAD: a meta-analysis.

INTRODUCTION AND OBJECTIVES: Coronary microvascular dysfunction (CMD) is highly prevalent and is recognized as an important clinical entity in patients with coronary artery disease (CAD). Nevertheless, the association of CMD with adverse cardiovascular events in the spectrum of CAD has not been systemically quantified. METHODS: We searched electronic databases for studies on patients with CAD in whom coronary microvascular function was measured invasively, and clinical events were recorded. The primary endpoint was major adverse cardiac events (MACE), and the secondary endpoint was all-cause death. Estimates of effect were calculated using a random-effects model from published risk ratios. RESULTS: We included 27 studies with 11 404 patients. Patients with CMD assessed by invasive methods had a higher risk of MACE (RR, 2.18; 95%CI, 1.80-2.64; P < .01) and all-cause death (RR, 1.88; 95%CI, 1.55-2.27; P < .01) than those without CMD. There was no significant difference in the impact of CMD on MACE (interaction P value = .95) among different invasive measurement modalities. The magnitude of risk of CMD assessed by invasive measurements for MACE was greater in acute coronary syndrome patients (RR, 2.84, 95%CI, 2.26-3.57; P < .01) than in chronic coronary syndrome patients (RR, 1.77, 95%CI, 1.44-2.18; P < .01) (interaction P value < .01). CONCLUSIONS: CMD based on invasive measurements was associated with a high incidence of MACE and all-cause death in patients with CAD. The magnitude of risk for cardiovascular events in CMD as assessed by invasive measurements was similar among different methods but varied among CAD populations.

Purification and characterization of limonin D-ring lactone hydrolase from sweet orange (Citrus sinensis (L.) Osbeck) seeds.

BACKGROUND: Citrus products often suffer from delayed bitterness, which is generated from the conversion of non-bitter precursors (limonoate A-ring lactone, LARL) to limonin under the catalysis of limonin D-ring lactone hydrolase (LDLH). In this study, LDLH was isolated and purified from sweet orange seeds, and a rapid and accurate high-performance liquid chromatography method to quantify LARL was developed and applied to analyze the activity and enzymatic properties of purified LDLH. RESULTS: Purified LDLH (25.22 U mg-1) showed bands of 245 kDa and 17.5 kDa molecular weights in native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate PAGE analysis respectively. After a 24 h incubation under strongly acidic (pH 3) or strongly alkaline (pH 9) conditions, LDLH still retained approximately 100% activity. Moreover, LDLH activity was not impaired by thermal treatment at 50 °C for 120 min. Enzyme inhibition assays showed that LDLH was inactivated only after ethylenediaminetetraacetic acid treatment, and other enzyme inhibitors showed no significant effect on its activity. In addition, the LDLH activity of calcium ion (Ca2+) intervention was 108% of that in the blank group, and that of zinc ion (Zn2+) intervention was 71%. CONCLUSION: LDLH purified in this study was a multimer containing 17.5 kDa monomer with a wide pH tolerance range (pH 3-9) and excellent thermal stability. Moreover, LDLH might be a metallopeptidase, and its activity was stimulated by Ca2+ and significantly inhibited by Zn2+. These findings improve our understanding of LDLH and provide some important implications for reducing the bitterness in citrus products in the future. © 2024 Society of Chemical Industry.

Interlayer Fermi Polarons of Excited Exciton States in Quantizing Magnetic Fields.

The study of exciton polarons has offered profound insights into the many-body interactions between bosonic excitations and their immersed Fermi sea within layered heterostructures. However, little is known about the properties of exciton polarons with interlayer interactions. Here, through magneto-optical reflectance contrast measurements, we experimentally investigate interlayer Fermi polarons for 2s excitons in WSe2/graphene heterostructures, where the excited exciton states (2s) in the WSe2 layer are dressed by free charge carriers of the adjacent graphene layer in the Landau quantization regime. First, such a system enables an optical detection of integer and fractional quantum Hall states (e.g., ν = ±1/3, ±2/3) of monolayer graphene. Furthermore, we observe that the 2s state evolves into two distinct branches, denoted as attractive and repulsive polarons, when graphene is doped out of the incompressible quantum Hall gaps. Our work paves the way for the understanding of the excited composite quasiparticles and Bose-Fermi mixtures.

Biomedical application of materials for external auditory canal: History, challenges, and clinical prospects.

Biomaterials play an integral role in treatment of external auditory canal (EAC) diseases. Regarding the special anatomic structure and physiological characteristics of EAC, careful selection of applicable biomaterials was essential step towards effective management of EAC conditions. The bioactive materials can provide reasonable biocompatibility, reduce risk of host pro-inflammatory response and immune rejection, and promote the healing process. In therapeutic procedure, biomaterials were employed for covering or packing the wound, protection of the damaged tissue, and maintaining of normal structures and functions of the EAC. Therefore, understanding and application of biomaterials was key to obtaining great rehabilitation in therapy of EAC diseases. In clinical practice, biomaterials were recognized as an important part in the treatment of different EAC diseases. The choice of biomaterials was distinct according to the requirements of various diseases. As a result, awareness of property regarding different biomaterials was fundamental for appropriate selection of therapeutic substances in different EAC diseases. In this review, we firstly introduced the characteristics of EAC structures and physiology, and EAC pathologies were summarized secondarily. From the viewpoint of biomaterials, the different materials applied to individual diseases were outlined in categories. Besides, the underlying future of therapeutic EAC biomaterials was discussed.

Realization of high-performance biosensor through sandwich analysis utilizing weak value amplification.

A label-free optical sandwich immunoassay sensor, utilizing weak value amplification and total internal reflection, was devised for real-time, high-sensitivity analysis and detection of low-concentration targets. 3D printed channels and sodium chloride solution were employed to ensure reproducibility, reliability, and stability of the measurements for calibration. The sandwich structure demonstrated enhanced responsiveness in the proposed optical biosensor through a comparative analysis of the direct assay and sandwich assay for detecting alpha-fetoprotein (AFP) at the same concentration. By optimizing the binding sequences of the coating antibody, target, and detection antibody in the sandwich method, a more suitable sandwich sensing approach based on weak value amplification was achieved. With this approach, the limit of detection (LOD) of 6.29 ng/mL (pM level) for AFP in PBS solution was achieved. AFP testing and regeneration experiments in human serum have proved the feasibility of our methods in detecting complex samples and the reusability of sensing chips. Additionally, the method demonstrated excellent selectivity for unpaired antigens. The efficacy of this methodology was evaluated by simultaneously detecting AFP, carcinoembryonic antigen (CEA), and CA15-3 on a singular sensor chip. In conclusion, the label-free sandwich immunoassay sensing scheme holds promise for advancing the proposed optical sensors based on weak value amplification in early diagnosis and prevention applications. Compared to other biomarker detection methods, it will be easier to promote in practical applications.

Synergistic Biofilter Tube for Promoting Scarless Tendon Regeneration.

Inspired by the imbalance between extrinsic and intrinsic tendon healing, this study fabricated a new biofilter scaffold with a hierarchical structure based on a melt electrowriting technique. The outer multilayered fibrous structure with connected porous characteristics provides a novel passageway for vascularization and isolates the penetration of scar fibers, which can be referred to as a biofilter process. In vitro experiments found that the porous architecture in the outer layer can effectively prevent cell infiltration, whereas the aligned fibers in the inner layer can promote cell recruitment and growth, as well as the expression of tendon-associated proteins in a simulated friction condition. It was shown in vivo that the biofilter process could promote tendon healing and reduce scar invasion. Herein, this novel strategy indicates great potential to design new biomaterials for balancing extrinsic and intrinsic healing and realizing scarless tendon healing.

Exploration of the Existence Forms and Patterns of Dissolved Oxygen Molecules in Water.

The structure of liquid water is primarily composed of three-dimensional networks of water clusters formed by hydrogen bonds, and dissolved oxygen is one of the most important indicators for assessing water quality. In this work, distilled water with different concentration of dissolved oxygen were prepared, and a clear negative correlation between the size of water clusters and dissolved oxygen concentration was observed. Besides, a phenomenon of rapid absorption and release of oxygen at the water interfaces was unveiled, suggesting that oxygen molecules predominantly exist at the interfaces of water clusters. Oxygen molecules can move rapidly through the interfaces among water clusters, allowing dissolved oxygen to quickly reach a saturation level at certain partial pressure of oxygen and temperature. Further exploration into the mechanism by molecular dynamics simulations of oxygen and water clusters found that oxygen molecules can only exist stably at the interfaces among water clusters. A semi-empirical formula relating the average number of water molecules in a cluster (n) to 17O NMR half-peak width (W) was summarized: n = 0.1 W + 0.85. These findings provide a foundation for exploring the structure and properties of water.

Exploring prognostic and immunological characteristics of pancreatic ductal adenocarcinoma through comprehensive genomic analysis of tertiary lymphoid structures and CD8 + T-cells.

PURPOSE: Tertiary lymphoid structures (TLSs) and CD8 + T-cells are potential prognostic indicators for pancreatic ductal adenocarcinoma (PDAC). We established a novel scoring system for evaluating the risk for PDAC based on TLS- and CD8 + T-cell-related genes. METHODS: We analyzed single-cell sequence data from PDAC patients in the Genome Sequence Archive. Bioinformatics and machine algorithms established and validated a scoring method (T-C score) based on PDAC survival-related genes highly expressed in TLSs and CD8 + T-cells. Patients were stratified into the low- and high-T-C score groups. Differences in survival, pathway enrichment, mutation status, immune cell infiltration, expression of immune checkpoint-associated genes, tumor stemness, and response to antitumor therapy were compared through computer simulation methods. RESULTS: Overall survival differed significantly between the training and validation cohorts' low- and high-T-C score groups. The low-T-C score group correlated with lower tumor mutation burden and lower levels of tumor stemness compared with the high-T-C score group. Patients with lower T-C scores exhibited advantages in immunotherapeutic responses and might be more sensitive to the chemotherapeutic regimen and multi-kinase inhibitors. CONCLUSION: The T-C score could serve as an effective model for predicting the survival and therapeutic responses of patients with PDAC.

Can major public health emergencies increase the participation of commercial insurance? Evidence from China.

Background: Public health emergencies have a lasting impact on a country's economic and social development. However, commercial insurance can disperse these negative consequences and reduce risk losses. Method: Based on the Chinese Household Tracking Survey and Peking University Digital Inclusive Finance Index, this study employed a difference-in-differences model to test the impact of the COVID-19 outbreak on commercial insurance participation and the impact mechanism. Results: The analysis showed that the outbreak of COVID-19 improved residents' risk perception, risk preference and digital finance and promoted their participation in commercial insurance, commercial endowment insurance, and commercial medical insurance. Conclusion: Major public health emergencies can increase commercial insurance participation, but the promotional effect of commercial insurance on rural and low-income individuals is relatively limited. To tap into potential customers, financial institutions should focus on vulnerable societal groups. This study supplements the relevant literature on the impact of major public health emergencies on commercial insurance participation.

Genetic polymorphism of IL-17 influences susceptibility to recurrent pregnancy loss in a Chinese population.

The current research aims to investigate the relationship between Interleukin-17 (IL-17) polymorphism and the risk of recurrent pregnancy loss (RPL) within a Chinese population. Totally, 120 patients with RPL were selected and enrolled as the experiment group. Additionally, 210 healthy individuals undergoing routine physical examinations during the same period served as the control group. The IL-17 gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism method. The IL-17 rs2275913 polymorphism exhibited 3 genotypes: GG, GA, and AA. Significant associations were observed with the AA genotype and A allele (all P < .05), indicating women with the AA genotype were 2.06 times more likely to experience RPL compared to those with the GG genotype. Similarly, women carrying the A allele faced a 1.63 times higher risk of RPL than those with the G allele. Regarding the IL-17 rs763780 polymorphism, which also presented 3 genotypes (TT, TC, CC), significant associations were noted for the CC genotype and C allele (all P < .05). Women with the CC genotype had a 1.84 times greater risk of suffering from RPL compared to those with the TT genotype, and those with the C allele were 1.51 times more likely to experience RPL than those with the T allele. The IL-17 rs2275913 and rs763780 polymorphisms contribute an increased risk to RPL in the Chinese population. Further studies, with larger sample sizes and more rigorous designs, are necessary to validate or replicate our current results.

Risk factor evaluation of cuff pressure of >30 cmH2O to stop air leakage during mechanical ventilation: A prospective observational study.

AIM: The commonly recommended endotracheal tube cuff pressure is 20-30 cmH2O. However, some patients require a cuff pressure of >30 cmH2O to prevent air leakage. The study aims to determine the risk factors that contribute to the endotracheal tube cuff pressure of >30 cmH2O to prevent air leakage. DESIGN: A multi-centre prospective observational study. METHODS: Eligible patients undergoing mechanical ventilation in the intensive care unit of three hospitals between March 2020 and July 2022 were included. The endotracheal tube cuff pressure to prevent air leakage was determined using the minimal occlusive volume technique. The patient demographics and clinical information were collected. RESULTS: A total of 284 patients were included. Among these patients, 55 (19.37%) patients required a cuff pressure of >30 cmH2O to prevent air leakage. The multivariate logistic regression results revealed that the surgical operation (odds ratio [OR]: 8.485, 95% confidence interval [CI]: 1.066-67.525, p = 0.043) was inversely associated with the endotracheal tube cuff pressure of >30 cmH2O, while the oral intubation route (OR: 0.127, 95% CI: 0.022-0.750, p = 0.023) and cuff inner diameter minus tracheal area (OR: 0.949, 95% CI: 0.933-0.966, p < 0.001) were negatively associated with the endotracheal tube cuff pressure of >30 cmH2O. Therefore, a significant number of patients require an endotracheal tube cuff pressure of ＞30 cmH2O to prevent air leakage. Several factors, including the surgical operation, intubation route, and difference between the cuff inner diameter and tracheal area at the T3 vertebra, should be considered when determining the appropriate cuff pressure during mechanical ventilation.

Glycyrol Relieves Ulcerative Colitis by Promoting the Fusion of ZO-1 with the Cell Membrane through the Enteric Glial Cells GDNF/RET Pathway.

The damage to the mechanical barrier of the intestinal mucosa is the initiating factor and the core link of the progression of ulcerative colitis (UC). Protecting the mechanical barrier of the intestinal mucosa is of great significance for improving the health status of UC patients. ZO-1 is a key scaffold protein of the mechanical barrier of the intestinal mucosa, and its fusion with the membrane of the intestinal epithelium is a necessary condition to maintain the integrity of the mechanical barrier of the intestinal mucosa. Enteric glial cells (EGCs) play an important role in the maintenance of intestinal homeostasis and have become a new target for regulating intestinal health in recent years. In this study, we found that glycyrol (GC), a representative coumarin compound isolated from Licorice (Glycyrrhiza uralensis Fisch, used for medicine and food), can alleviate UC by promoting the production of neurotrophic factor GDNF in mice EGCs. Specifically, we demonstrated that GC promotes the production of GDNF, then activates its receptor RET, promotes ZO-1 fusion with cell membranes, and protects the intestinal mucosal mechanical barrier. The results of this study can provide new ideas for the prevention and treatment of UC.

Deep learning models for predicting the survival of patients with hepatocellular carcinoma based on a surveillance, epidemiology, and end results (SEER) database analysis.

Hepatocellular carcinoma (HCC) is a common malignancy with poor survival and requires long-term follow-up. Hence, we collected information on patients with Primary Hepatocellular Carcinoma in the United States from the Surveillance, Epidemiology, and EndResults (SEER) database. We used this information to establish a deep learning with a multilayer neural network (the NMTLR model) for predicting the survival rate of patients with Primary Hepatocellular Carcinoma. HCC patients pathologically diagnosed between January 2011 and December 2015 in the SEER (Surveillance, Epidemiology, and End Results) database of the National Cancer Institute of the United States were selected as study subjects. We utilized two deep learning-based algorithms (DeepSurv and Neural Multi-Task Logistic Regression [NMTLR]) and a machine learning-based algorithm (Random Survival Forest [RSF]) for model training. A multivariable Cox Proportional Hazards (CoxPH) model was also constructed for comparison. The dataset was randomly divided into a training set and a test set in a 7:3 ratio. The training dataset underwent hyperparameter tuning through 1000 iterations of random search and fivefold cross-validation. Model performance was assessed using the concordance index (C-index), Brier score, and Integrated Brier Score (IBS). The accuracy of predicting 1-year, 3-year, and 5-year survival rates was evaluated using Receiver Operating Characteristic (ROC) curves, calibration plots, and Area Under the Curve (AUC). The primary outcomes were the 1-year, 3-year, and 5-year overall survival rates. Models were developed using DeepSurv, NMTLR, RSF, and Cox Proportional Hazards regression. Model differentiation was evaluated using the C-index, calibration with concordance plots, and risk stratification capability with the log-rank test. The study included 2197 HCC patients, randomly divided into a training cohort (70%, n = 1537) and a testing cohort (30%, n = 660). Clinical characteristics between the two cohorts showed no significant statistical difference (p > 0.05). The deep learning models outperformed both RSF and CoxPH models, with C-indices of 0.735 (NMTLR) and 0.731 (DeepSurv) in the test dataset. The NMTLR model demonstrated enhanced accuracy and well-calibrated survival estimates, achieving an Area Under the Curve (AUC) of 0.824 for 1-year survival predictions, 0.813 for 3-year, and 0.803 for 5-year survival rates. This model's superior calibration and discriminative ability enhance its utility for clinical prognostication in Primary Hepatocellular Carcinoma. We deployed the NMTLR model as a web application for clinical practice. The NMTLR model have potential advantages over traditional linear models in prognostic assessment and treatment recommendations. This novel analytical approach may provide reliable information on individual survival and treatment recommendations for patients with primary liver cancer.

Preparation and efficacy of antibacterial methacrylate monomer-based polymethyl methacrylate bone cement containing N-halamine compounds.

Introduction: Our objective in this study was to prepare a novel type of polymethyl methacrylate (PMMA) bone cement, analyze its material properties, and evaluate its safety and antibacterial efficacy. Methods: A halamine compound methacrylate antibacterial PMMA bone cement containing an N-Cl bond structure was formulated, and its material characterization was determined with Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR. The antibacterial properties of the material were studied using contact bacteriostasis and releasing-type bacteriostasis experiments. Finally, in vitro and in vivo biocompatibility experiments were performed to analyze the toxic effects of the material on mice and embryonic osteoblast precursor cells (MC3T3-E1). Results: Incorporation of the antibacterial methacrylate monomer with the N-halamine compound in the new antibacterial PMMA bone cement significantly increased its contact and releasing-type bacteriostatic performance against Staphylococcus aureus. Notably, at 20% and 25% additions of N-halamine compound, the contact and releasing-type bacteriostasis rates of bone cement samples reached 100% (p < 0.001). Furthermore, the new antibacterial bone cement containing 5%, 10%, and 15% N-halamine compounds showed good biocompatibility in vitro and in vivo. Conclusion: In this study, we found that the novel antibacterial PMMA bone cement with N-halamine compound methacrylate demonstrated good contact and releasing-type bacteriostatic properties against S. aureus. In particular, bone cement containing a 15% N-halamine monomer exhibited strong antibacterial properties and good in vitro and in vivo biocompatibility.

A novel controllable capacitor commutation based superconducting hybrid direct current breaker.

Featuring low power loss and high reliability, voltage source converter medium voltage direct current (VSC-MVDC) systems have been widely employed for grid-tied renewable energy applications. To maintain high operational safety, circuit breakers are needed to isolate faulted powerlines by comprehensively considering response speed and installation cost. Research efforts have been put to realizing DC fault isolation by coordinating resistive type superconducting fault current limiter (R-SFCL) and integrated-gate-commutated-thyristor (IGCT) based hybrid DC circuit breaker. In this paper, a controllable current commutation based superconducting DC circuit breaker (CCCB-SDCCB) is proposed. By integrating R-SFCL with IGCT based hybrid DC circuit breakers, the current interrupting capacity can be greatly enlarged with the advantage of low cost and fast speed, and hence the overall cost for suppress large fault currents can be greatly reduced for MVDC systems. In addition, a new current injection circuit branch using H-bridge structure is designed to recycle the residual capacitor voltage from the previous fault stage to trigger the IGCTs without the capacitor pre-charging process. Simulation results show that the fault current can be successfully suppressed from 24.2 to 2.1 kA and fully interrupted within 4.11 ms by the proposed CCCB-SDCCB.