Lethal pulmonary thromboembolism in mice induced by intravenous human umbilical cord mesenchymal stem cell-derived large extracellular vesicles in a dose- and tissue factor-dependent manner.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have obvious advantages over MSC therapy. But the strong procoagulant properties of MSC-EVs pose a potential risk of thromboembolism, an issue that remains insufficiently explored. In this study, we systematically investigated the procoagulant activity of large EVs derived from human umbilical cord MSCs (UC-EVs) both in vitro and in vivo. UC-EVs were isolated from cell culture supernatants. Mice were injected with UC-EVs (0.125, 0.25, 0.5, 1, 2, 4 µg/g body weight) in 100 µL PBS via the tail vein. Behavior and mortality were monitored for 30 min after injection. We showed that these UC-EVs activated coagulation in a dose- and tissue factor-dependent manner. UC-EVs-induced coagulation in vitro could be inhibited by addition of tissue factor pathway inhibitor. Notably, intravenous administration of high doses of the UC-EVs (1 µg/g body weight or higher) led to rapid mortality due to multiple thrombus formations in lung tissue, platelets, and fibrinogen depletion, and prolonged prothrombin and activated partial thromboplastin times. Importantly, we demonstrated that pulmonary thromboembolism induced by the UC-EVs could be prevented by either reducing the infusion rate or by pre-injection of heparin, a known anticoagulant. In conclusion, this study elucidates the procoagulant characteristics and mechanisms of large UC-EVs, details the associated coagulation risk during intravenous delivery, sets a safe upper limit for intravenous dose, and offers effective strategies to prevent such mortal risks when high doses of large UC-EVs are needed for optimal therapeutic effects, with implications for the development and application of large UC-EV-based as well as other MSC-EV-based therapies.

N-acetylcysteine Protects Against Myocardial Ischemia-Reperfusion Injury Through Anti-ferroptosis in Type 1 Diabetic Mice.

The hearts of subjects with diabetes are vulnerable to ischemia-reperfusion injury (IRI). In contrast, experimentally rodent hearts have been shown to be more resistant to IRI at the very early stages of diabetes induction than the heart of the non-diabetic control mice, and the mechanism is largely unclear. Ferroptosis has recently been shown to play an important role in myocardial IRI including that in diabetes, while the specific mechanisms are still unclear. Non-diabetic control (NC) and streptozotocin-induced diabetic (DM) mice were treated with the antioxidant N-acetylcysteine (NAC) in drinking water for 4 week starting at 1 week after diabetes induction. Mice were subjected to myocardial IRI induced by occluding the coronary artery for 30 min followed by 2 h of reperfusion, subsequently at 1, 2, and 5 week of diabetes induction. The post-ischemic myocardial infarct size in the DM mice was smaller than that in NC mice at 1 week of diabetes but greater than that in the NC mice at 2 and 5 week of diabetes, which were associated with a significant increase of ferroptosis at 2 and 5 week but a significant reduction of ferroptosis at 1 week of diabetes. NAC significantly attenuated post-ischemic ferroptosis as well as oxidative stress and reduced infarct size at 2 and 5 week of diabetes. Application of erastin, a ferroptosis inducer, reversed the cardioprotective effects of NAC. It is concluded that increased oxidative stress and ferroptosis are the major factors attributable to the increased vulnerability to myocardial IRI in diabetes and that attenuation of ferroptosis represents a major mechanism whereby NAC confers cardioprotection against myocardial IRI in diabetes.

Propofol and salvianolic acid A synergistically attenuated cardiac ischemia-reperfusion injury in diabetic mice via modulating the CD36/AMPK pathway.

Background: Prevention of diabetic heart myocardial ischemia-reperfusion (IR) injury (MIRI) is challenging. Propofol attenuates MIRI through its reactive oxygen species scavenging property at high doses, while its use at high doses causes hemodynamic instability. Salvianolic acid A (SAA) is a potent antioxidant that confers protection against MIRI. Both propofol and SAA affect metabolic profiles through regulating Adenosine 5'-monophosphate-activated protein kinase (AMPK). The aim of this study was to investigate the protective effects and underlying mechanisms of low doses of propofol combined with SAA against diabetic MIRI. Methods: Diabetes was induced in mice by a high-fat diet followed by streptozotocin injection, and MIRI was induced by coronary artery occlusion and reperfusion. Mice were treated with propofol at 46 mg/kg/h without or with SAA at 10 mg/kg/h during IR. Cardiac origin H9c2 cells were exposed to high glucose (HG) and palmitic acid (PAL) for 24 h in the absence or presence of cluster of differentiation 36 (CD36) overexpression or AMPK gene knockdown, followed by hypoxia/reoxygenation (HR) for 6 and 12 h. Results: Diabetes-exacerbated MIRI is evidenced as significant increases in post-ischemic infarction with reductions in phosphorylated (p)-AMPK and increases in CD36 and ferroptosis. Propofol moderately yet significantly attenuated all the abovementioned changes, while propofol plus SAA conferred superior protection against MIRI to that of propofol. In vitro, exposure of H9c2 cells under HG and PAL decreased cell viability and increased oxidative stress that was concomitant with increased levels of ferroptosis and a significant increase in CD36, while p-AMPK was significantly reduced. Co-administration of low concentrations of propofol and SAA at 12.5 µM in H9c2 cells significantly reduced oxidative stress, ferroptosis and CD36 expression, while increasing p-AMPK compared to the effects of propofol at 25 µM. Moreover, either CD36 overexpression or AMPK silence significantly exacerbated HR-induced cellular injuries and ferroptosis, and canceled propofol- and SAA-mediated protection. Notably, p-AMPK expression was downregulated after CD36 overexpression, while AMPK knockdown did not affect CD36 expression. Conclusions: Combinational usage of propofol and SAA confers superior cellular protective effects to the use of high-dose propofol alone, and it does so through inhibiting HR-induced CD36 overexpression to upregulate p-AMPK.

Targeting Senescent Alveolar Epithelial Cells Using Engineered Mesenchymal Stem Cell-Derived Extracellular Vesicles To Treat Pulmonary Fibrosis.

Type 2 alveolar epithelial cell (AEC2) senescence is crucial to the pathogenesis of pulmonary fibrosis (PF). The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme cluster of differentiation 38 (CD38) is a marker of senescent cells and is highly expressed in AEC2s of patients with PF, thus rendering it a potential treatment target. Umbilical cord mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) have emerged as a cell-free treatment with clinical application prospects in antiaging and antifibrosis treatments. Herein, we constructed CD38 antigen receptor membrane-modified MSC-EVs (CD38-ARM-MSC-EVs) by transfecting MSCs with a lentivirus loaded with a CD38 antigen receptor-CD8 transmembrane fragment fusion plasmid to target AEC2s and alleviate PF. Compared with MSC-EVs, the CD38-ARM-MSC-EVs engineered in this study showed a higher expression of the CD38 antigen receptor and antifibrotic miRNAs and targeted senescent AEC2s cells highly expressing CD38 in vitro and in naturally aged mouse models after intraperitoneal administration. CD38-ARM-MSC-EVs effectively restored the NAD+ levels, reversed the epithelial-mesenchymal transition phenotype, and rejuvenated senescent A549 cells in vitro, thereby mitigating multiple age-associated phenotypes and alleviating PF in aged mice. Thus, this study provides a technology to engineer MSC-EVs and support our CD38-ARM-MSC-EVs to be developed as promising agents with high clinical potential against PF.

Procoagulant Properties of Mesenchymal Stem Cells and Extracellular Vesicles: A Novel Aspect of Thrombosis Pathogenesis.

Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into various cell types and secrete extracellular vesicles (EVs) that transport bioactive molecules and mediate intercellular communication. MSCs and MSC-derived EVs (MSC-EVs) have shown promising therapeutic effects in several diseases. However, their procoagulant activity and thrombogenic risk may limit their clinical safety. In this review, we summarize current knowledge on procoagulant molecules expressed on the surface of MSCs and MSC-EVs, such as tissue factor and phosphatidylserine. Moreover, we discuss how these molecules interact with the coagulation system and contribute to thrombus formation through different mechanisms. Additionally, various confounding factors, such as cell dose, tissue source, passage number, and culture conditions of MSCs and subpopulations of MSC-EVs, affect the expression of procoagulant molecules and procoagulant activity of MSCs and MSC-EVs. Therefore, herein, we summarize several strategies to reduce the surface procoagulant activity of MSCs and MSC-EVs, thereby aiming to improve their safety profile for clinical use.

Targeting cytohesin-1 suppresses acute myeloid leukemia progression and overcomes resistance to ABT-199.

Adhesion molecules play essential roles in the homeostatic regulation and malignant transformation of hematopoietic cells. The dysregulated expression of adhesion molecules in leukemic cells accelerates disease progression and the development of drug resistance. Thus, targeting adhesion molecules represents an attractive anti-leukemic therapeutic strategy. In this study, we investigated the prognostic role and functional significance of cytohesin-1 (CYTH1) in acute myeloid leukemia (AML). Analysis of AML patient data from the GEPIA and BloodSpot databases revealed that CYTH1 was significantly overexpressed in AML and independently correlated with prognosis. Functional assays using AML cell lines and an AML xenograft mouse model confirmed that CYTH1 depletion significantly inhibited the adhesion, migration, homing, and engraftment of leukemic cells, delaying disease progression and prolonging animal survival. The CYTH1 inhibitor SecinH3 exerted in vitro and in vivo anti-leukemic effects by disrupting leukemic adhesion and survival programs. In line with the CYTH1 knockdown results, targeting CYTH1 by SecinH3 suppressed integrin-associated adhesion signaling by reducing ITGB2 expression. SecinH3 treatment efficiently induced the apoptosis and inhibited the growth of a panel of AML cell lines (MOLM-13, MV4-11 and THP-1) with mixed-lineage leukemia gene rearrangement, partly by reducing the expression of the anti-apoptotic protein MCL1. Moreover, we showed that SecinH3 synergized with the BCL2-selective inhibitor ABT-199 (venetoclax) to inhibit the proliferation and promote the apoptosis of ABT-199-resistant leukemic cells. Taken together, our results not only shed light on the role of CYTH1 in cell-adhesion-mediated leukemogenesis but also propose a novel combination treatment strategy for AML.

Upper Limb Movement Decoding Scheme Based on Surface Electromyography Using Attention-Based Kalman Filter Scheme.

Convolutional neural network (CNN)-based models are widely used in human movement decoding based on surface electromyography. However, they capture only the spatial information of the surface electromyography and lack prior knowledge of the system, resulting in unsatisfactory decoding accuracy. To address these issues, we propose an attention-based Kalman filter scheme (AKFS), which uses an attention-based CNN model to better extract temporal information and a KF to add prior knowledge of the system. We further solve the problem of insufficient data due to the short training time of new subjects by using a transfer learning method based on a fine-tuning strategy. The proposed scheme was tested in four scenarios: intra-session, intra-session long-time use, inter-subject, and inter-subject with a fine-tuning strategy. The proposed attention-based CNN model outperformed the vanilla CNN model and a hybrid CNN-long short-term memory (LSTM) model in intra-session and intra-session long-time use. After fine-tuning with a small amount of data on a new subject, the attention-based CNN model achieved higher decoding accuracy than the vanilla CNN model and lower response time than CNN-LSTM model. Furthermore, the schemes with KF outperformed the schemes without KF in all scenarios. Our proposed scheme improves the decoding accuracy of the traditional CNN model for a single subject by better capturing the temporal information of the surface electromyography signal and increasing the prior knowledge of the system. Additionally, the proposed scheme can be easily transferred to a new subject using only a small amount of data.

Efficacy of indocyanine green fluorescence imaging-guided lymphadenectomy in radical gastrectomy for gastric cancer: A systematic review and meta-analysis.

Background: Indocyanine green (ICG) imaging-guided lymphadenectomy has been introduced in gastric cancer (GC) surgery and its clinical value remains controversial. The aim of this study is to evaluate the efficacy of ICG fluorescence imaging-guided lymphadenectomy in radical gastrectomy for GC. Methods: Studies comparing lymphadenectomy in radical gastrectomy between use and non-use of ICG fluorescence imaging up to July 2022 were systematically searched from PubMed, Web of Science, Embase and Cochrane Library. A pooled analysis was performed for the available data regarding the baseline features, the number of retrieved lymph nodes (LNs), the number of metastatic LNs and surgical outcomes as well as oncological outcomes. RevMan 5.3 software was used to perform the statistical analysis. Quality evaluation and publication bias were also conducted. Results: 17 studies with a total of 2274 patients (1186 in the ICG group and 1088 in the control group) undergoing radical gastrectomy and lymphadenectomy were included. In the pooled analysis, the baseline features were basically comparable. However, the number of retrieved LNs in the ICG group was significantly more than that in the control group (MD = 7.41, 95% CI = 5.44 to 9.37, P < 0.00001). No significant difference was found between the ICG and control groups in terms of metastatic LNs (MD = -0.05, 95% CI = -0.25 to 0.16, P = 0.65). In addition, the use of ICG could reduce intraoperative blood loss (MD = -17.96, 95% CI = -27.89 to -8.04, P = 0.0004) without increasing operative time (P = 0.14) and overall complications (P = 0.10). In terms of oncological outcomes, the use of ICG could reduce the overall recurrence rate (OR = 0.50; 95% CI 0.28-0.89; P = 0.02) but could not increase the 2-year overall survival rate (OR = 1.25; 95% CI 0.72-2.18; P = 0.43). Conclusions: ICG imaging-guided lymphadenectomy is valuable for complete LNs dissection in radical gastrectomy for GC. However, more high-quality randomized controlled trials are needed to confirm this benefit.

Improvement of EMG Pattern Recognition Model Performance in Repeated Uses by Combining Feature Selection and Incremental Transfer Learning.

Electromyography (EMG) pattern recognition is one of the widely used methods to control the rehabilitation robots and prostheses. However, the changes in the distribution of EMG data due to electrodes shifting results in classification decline, which hinders its clinical application in repeated uses. Adaptive learning can solve this problem but takes additional time. To address this, an efficient scheme is developed by comparing the performance of 12 combinations of three feature selection methods [no feature selection (NFS), sequential forward search (SFS), and particle swarm optimization (PSO)] and four classification methods [non-adaptive support vector machine (N-SVM), incremental SVM (I-SVM), SVM based on TrAdaBoost (T-SVM), and I-SVM based on TrAdaBoost (TI-SVM)] in the classification of EMG data of 12 subjects for 5 consecutive days. Our results showed that TI-SVM achieved the highest classification accuracy among the classification methods (p < 0.05). The SFS method achieved the same classification accuracy as that of the scheme trained with the feature vectors selected by the NFS method (p = 0.999) while achieving a lower training time than that of TI-SVM combined with the NFS method (p = 0.043). Although the PSO method outperformed the NFS and SFS methods by achieving reduced training and response times (p < 0.05), the PSO method achieved a considerably lower classification accuracy than that of the scheme trained with the feature vectors selected by the NFS (p = 0.001) or SFS (p = 0.001) method. Furthermore, TI-SVM combined with the SFS method outperformed the CNN method with fine-tuning in classification accuracy on a small data set (p = 0.001). The results indicate that TI-SVM combined with the SFS method is suitable for improving the performance of EMG pattern recognition in repeated uses.

Proteomics analysis of chicken peripheral blood lymphocyte in Taishan Pinus massoniana pollen polysaccharide regulation.

The natural polysaccharides extracted from the pollen of Pinus massoniana (TPPPS) have been shown to be a promising immune adjuvant against several viral chicken diseases. However, the exact mechanism through which TPPPS enhances the host immune response in chicken remains poorly understood. In the current study, chicken peripheral blood lymphocytes were treated with varying concentrations of TPPPS and pro-inflammatory cytokines such as IFN-γ, iIL-2 and IL-6 were measured to determine the optimal dose of the polysaccharide. A comparative analysis was subsequently performed between the proteome of lymphocytes subjected to the best treatment conditions and that of untreated cells. Protein identification and quantitation revealed a panel of three up-regulated and seven down-regulated candidates in TPPPS-treated chicken peripheral blood lymphocytes. Further annotation and functional analysis suggested that a number of those protein candidates were involved in the regulation of host innate immune response, inflammation and other immune-related pathways. We believe that our results could serve as a stepping stone for further research on the immune-enhancing properties of TPPPS and other polysaccharide-based immune adjuvants.

Five new C21 steroidal glycosides from the stems of Marsdenia tenacissima.

Five new C(21) steroidal glycosides (1-5) were isolated from the stems of Marsdenia tenacissima. The chemical structures and relative configurations of the new compounds were elucidated by mass spectrometry and NMR spectroscopy. Cellular assay of these compounds showed that they are weak cytotoxic to various cell lines.