An important issue of burnout among pre-hospital emergency medical personnel in Chengdu: a cross-sectional study.

OBJECTIVE: This survey aims to comprehensively understand occupational burnout among pre-hospital emergency medical personnel and explore associated risk factors. METHODS: A cross-sectional online survey using a census method was conducted between 15 July, 2023, and ends on 14 August, 2023, in Chengdu, SiChuan province, China. The questionnaire included general demographic information, the Maslach Burnout Inventory-General Survey (MBI-GS) with 15 items, and the Fatigue Scale-14 (FS-14) with 14 items. Univariate analysis was conducted on all variables, followed by multivariate logistic regression models to examine the associations between occupational burnout and the risk factors. RESULTS: A total of 2,299 participants,99.57% completed the survey effectively The participants were from 166 medical institutions in Chengdu, comprising 1,420 nurses (61.50%) and 889 clinical doctors (38.50%). A total of 33.36% participants experienced burnout, predominantly mild (30.27%), followed by moderate (2.78%) and severe (0.3%). Physicians, higher fatigue scores, age, work experience appeared to be related to burnout. Logistic regression models revealed that individuals aged over 50 were less prone to experience burnout compared to medical staff aged 18-30 (OR: 0.269, 95% CI: 0.115-0.627, p = 0.002). Physicians were more prone to experience burnout compared to nursing staff (OR: 0.690, 95% CI: 0.531-0.898, p = 0.006). Those with 0-5 years of experience were more prone to experience burnout compared to those with 6-10 years or over 15 years of experience (OR: 0.734, 95% CI: 0.547-0.986, p = 0.040; OR: 0.559, 95% CI: 0.339-0.924, p = 0.023). Additionally, for each 1-point increase in the fatigue score, the likelihood of burnout in medical staff increased by 1.367 times (OR: 1.367, 95% CI: 1.323-1.412, p < 0.0001). CONCLUSION: Pre-hospital emergency medical personnel demonstrate a notable prevalence of mild job burnout. These results provide a groundwork for future focus on the various stages of job burnout within pre-hospital emergency staff, alerting hospital and departmental managers to promptly address the mental well-being of their personnel and intervene as needed.

Association between periprocedural myocardial injury and neointimal characteristics in patients with in-stent restenosis: an optical coherence tomography study.

Background: The relationship between neointimal characteristics of in-stent restenosis (ISR) and periprocedural myocardial injury (PMI) remains unclear. Therefore, this study aimed to investigate the relationship between PMI and neointimal characteristics of ISR by using optical coherence tomography (OCT). Methods: This was a retrospective study. We enrolled 140 patients diagnosed with ISR with normal baseline high-sensitivity troponin T (hs-cTnT) levels who underwent OCT and subsequent revascularization by means of drug-coated balloon (DCB) or drug-eluting stent (DES) between October 2018 and October 2022 in the Affiliated Hospital of Zunyi Medical University. Based on the 4th universal definition of myocardial infarction, patients whose hs-cTnT were increased five times above the upper reference limit (URL) after percutaneous coronary interventions (PCI) were deemed to PMI. The patients were subdivided into PMI (n=53) and non-PMI (n=87) groups. In the univariable analysis, variables in the baselines, angiography characteristics and OCT findings were analyzed with binary logistic regression. A P value of <0.2 was included in the multivariable model. Multivariable logistic regression analysis was used to identify the independent predictors of PMI. Results: The prevalence of intra-intimal microvessels in patients with PMI was higher than in those without PMI (58.5% vs. 32.2%, P=0.003). The ratio of intra-stent plaque rupture (PR) was also higher in patients with PMI (60.4% vs. 40.2%, P=0.021). Multivariable logistic regression analysis showed that intra-intimal microvessels [odds ratio (OR): 3.193, 95% confidence interval (CI): 1.280-7.966; P=0.013] and intra-stent PR (OR: 2.124, 95% CI: 1.153-4.732; P=0.035) were independently associated with PMI. Conclusions: Intra-intimal microvessels and intra-stent PR were independently associated with PMI. Accurate identification and recognition of intra-intimal microvessels and intra-stent PR may be helpful in preventing PMI.

Morphological characteristics of in-stent restenosis with different degrees of area stenosis: an optical coherence tomography study.

The morphological characteristics of in-stent restenosis (ISR) in relation to varying degrees of area stenosis have not been comprehensively examined. This study aimed to explore the tissue characteristics of patients experiencing ISR with different degrees of area stenosis through the utilization of optical coherence tomography (OCT). In total, 230 patients with ISR who underwent OCT were divided into the following three groups: area stenosis (AS) < 70% (n = 26); 70-80% (n = 119) and AS ≥ 80% (n = 85). Among the 230 patients, the clinical presentation as stable angina was 61.5% in AS < 70%, followed by 47.2% in 70% < AS ≤ 80%, and 31.8% in AS ≥ 80% (P = 0.010). The OCT findings showed that heterogeneous neointima, ISNA, LRP, neointima rupture, TCFA-like pattern, macrophage infiltration, red and white thrombus was more common with AS increased. Ordinal logistic regression analysis showed that higher AS was associated with previous dyslipidemia (odds ratio [OR], 4.754; 95% confidence interval [CI], 1.419-15.927, P = 0.011), neointimal rupture (OR: 3.640; 95% CI, 1.169-11.325, P = 0.026), red thrombus (OR: 4.482; 95% CI, 1.269-15.816, P = 0.020) and white thrombus (OR: 5.259; 95% CI, 1.660-16.659, P = 0.005). Patients with higher degrees of area stenosis in the context of ISR exhibited a greater number of discernible morphological characteristics as identified through OCT analysis. Furthermore, previous dyslipidemia, neointimal rupture, white thrombus and red thrombus were highly associated with and the progression of ISR lesions.

Association Between Serum Uric Acid Levels and Neoatherosclerosis.

Neoatherosclerosis is a major cause of stent failure after percutaneous coronary intervention. Metabolism such as hyperuricemia is associated with in-stent restenosis (ISR). However, the association between serum uric acid (sUA) levels and in-stent neoatherosclerosis (ISNA) has never been validated.A total of 216 patients with 220 ISR lesions who had undergone optical coherence tomography (OCT) of culprit stents were included in this study. According to their sUA levels, eligible patients were divided into two groups [normal-sUA group: sUA < 7 mg/dL, n = 126, and high-sUA group: sUA ≥ 7 mg/dL, n = 90]. OCT findings were analyzed and compared between the normal- and high-sUA groups.The incidence of ISNA (63.0% versus 43.0%, P = 0.004) was significantly higher in the high-sUA group than in the normal-sUA group. Lipid plaques (66.3% versus 43.0%, P < 0.001) and thin-cap fibroatheroma (38.0% versus 18.0%, P = 0.001) were observed more frequently in the restenotic tissue structure in patients in the high-sUA group than in those in the normal-sUA group. Meanwhile, univariate (OR: 1.208, 95% CI: 1.037-1.407; P = 0.015) and multivariate (OR: 1.254, 95% CI: 1.048-1.501; P = 0.013) logistic regression analyses indicated that sUA levels were an independent risk factor for ISNA after adjusting for relevant risk factors.The high-sUA levels were an independent risk factor for the occurrence of neoatherosclerosis in patients with ISR via OCT.

An Overview of Systematic Reviews and Meta-Analyses of Clinical Studies of Acupuncture for Cancer Pain.

BACKGROUND: Systematic reviews (SRs) and meta-analyses (MAs) for the use of acupuncture for cancer pain have been increasing, but the evidence has not been systematically and comprehensively assessed. We aimed to perform an overview of the evidence quality of SRs/MAs of acupuncture for improving cancer pain. METHODS: 8 databases were systematically searched to identify SRs/MAs of acupuncture for improving cancer pain. The A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR-2), Risk of Bias in Systematic Reviews (ROBIS), Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and Grades of Recommendations, Assessment, Development, and Evaluation (GRADE), respectively, were applied by 2 independent reviewers to evaluate the methodological quality, risk of bias, reporting quality, and evidence quality. RESULTS: A total of 14 SRs/MAs were included in the present study. By AMSTAR-2, two reviews were rated as having high methodological quality, while 12 were given a critically low rating. All SRs/MAs in Phase 1, Domain 1, and Domain 4, according to ROBIS, were at low risk. Furthermore, 4 reviews in Domain 2, twelve reviews in Domain 3, and ten SRs/MAs in Phase 3, were rated as having low risk of bias. With reporting quality, some reporting flaws were identified in the topic of protocol and registration, additional analyses, and search strategy. According to GRADE, the level of evidence quality was "critically low" to "moderate," and risk of bias was the most common downgraded factor. CONCLUSION: Acupuncture may be beneficial in improving cancer pain. However, due to the identified limitations and inconsistent findings, we recommend further rigorous, and more standardized SRs/MAs to provide strong evidence for definitive conclusions.

Association of LDL-C level with neoatherosclerosis and plaque vulnerability in patients with late restenosis: an optical coherence tomography study.

Neoatherosclerosis (NA) is a significant contributor to late stent failure; however, predictors of late in-stent restenosis (ISR) with NA have not been systematically reported. This study aimed to identify predictors of NA incidence and plaque vulnerability in patients with late ISR and the role of low-density lipoprotein cholesterol (LDL-C) levels in this process. A total of 216 patients with 216 lesions who underwent optical coherence tomography (OCT) before interventional procedure for late drug-eluting stent ISR were enrolled and divided into NA and non-NA groups based on OCT findings. Results showed that higher LDL-C levels were associated with NA, thin-cap fibroatheroma (TCFA), intimal disruption, plaque erosion, and thrombosis. Multivariate regression analysis revealed that the LDL-C level was an independent risk factor for NA and TCFA. The LDL-C levels exhibited a significant predictive value for NA and TCFA, surpassing other factors such as stent age and other lipid types. In conclusion, a high LDL-C level is an independent predictor of NA incidence and plaque vulnerability in patients with late ISR.

Coal-gangue recognition via multi-branch convolutional neural network based on MFCC in noisy environment.

Traditional coal-gangue recognition methods usually do not consider the impact of equipment noise, which severely limits its adaptability and recognition accuracy. This paper mainly studies the more accurate recognition of coal-gangue in the noise site environment with the operation of shearer, conveyor, transfer machine and other device in the process of top coal caving. Mel Frequency Cepstrum Coefficients (MFCC) smoothing method was introduced to express the intrinsic feature of sound pressure more clearly in the coal-gangue recognition site. Then, a multi-branch convolution neural network (MBCNN) model with three branches was developed, and the smoothed MFCC feature was incorporated into this model to realize the recognition of falling coal and gangue in noisy environment. The sound pressure signal datasets under the operation of different device were constructed through a great deal of laboratory and site data acquisition. Comparative experiments were carried out on noiseless dataset, single noise dataset and simulated site dataset, and the results show that our method can provide higher correct recognition accuracy and better robustness. The proposed coal-gangue recognition approach based on MBCNN and MFCC smoothing can not only recognize the state of falling coal or gangue, but also recognize the operational state of site device.

COVID-19 crisis impact on the stability between parties in crowdfunding and crowdsourcing.

This research reviews challenges in building sustainable relationships between the parties involved in the crowdfunding and crowdsourcing projects, which are running in extreme situations, such as the COVID-19 pandemic. This study aims to solve problems that generate the crowdsourcing concerns and to find better alternatives to increase trust for crowdfunding among donors, as this impacts their strategic sustainability in the conditions of turbulence and COVID-induced financial crisis. It was found that factors influence donor decisions in different ways, yet the common tendency for donor activity is non-monotonicity. Future development in the field of sustainable relationships should focus on creating a donor classification system.

Development of a machine learning model to predict the risk of late cardiogenic shock in patients with ST-segment elevation myocardial infarction.

BACKGROUND: The in-hospital mortality of patients with ST-segment elevation myocardial infarction (STEMI) increases to more than 50% following a cardiogenic shock (CS) event. This study highlights the need to consider the risk of delayed calculation in developing in-hospital CS risk models. This report compared the performances of multiple machine learning models and established a late-CS risk nomogram for STEMI patients. METHODS: This study used logistic regression (LR) models, least absolute shrinkage and selection operator (LASSO), support vector regression (SVM), and tree-based ensemble machine learning models [light gradient boosting machine (LightGBM) and extreme gradient boosting (XGBoost)] to predict CS risk in STEMI patients. The models were developed based on 1,598 and 684 STEMI patients in the training and test datasets, respectively. The models were compared based on accuracy, the area under the curve (AUC), recall, precision, and Gini score, and the optimal model was used to develop a late CS risk nomogram. Discrimination, calibration, and the clinical usefulness of the predictive model were assessed using C-index, calibration plotd, and decision curve analyses. RESULTS: A total of 2282 STEMI patients recruited between January 1, 2016 and May 31, 2020, were included in the complete dataset. The linear models built using LASSO and LR showed the highest overall predictive power, with an average accuracy over 0.93 and an AUC above 0.82. With a C-index of 0.811 [95% confidence interval (CI): 0.769-0.853], the LASSO nomogram showed good differentiation and proper calibration. In internal validation tests, a high C-index value of 0.821 was achieved. Decision curve analysis (DCA) and clinical impact curve (CIC) examination showed that compared with the previous score-based models, the LASSO model showed superior clinical relevance. CONCLUSIONS: In this study, five machine learning methods were developed for in-hospital CS prediction. The LASSO model showed the best predictive performance. This nomogram could provide an accurate prognostic prediction for CS risk in patients with STEMI.

Clinical Feature-Based Machine Learning Model for 1-Year Mortality Risk Prediction of ST-Segment Elevation Myocardial Infarction in Patients with Hyperuricemia: A Retrospective Study.

Accurate risk assessment of high-risk patients is essential in clinical practice. However, there is no practical method to predict or monitor the prognosis of patients with ST-segment elevation myocardial infarction (STEMI) complicated by hyperuricemia. We aimed to evaluate the performance of different machine learning models for the prediction of 1-year mortality in STEMI patients with hyperuricemia. We compared five machine learning models (logistic regression, k-nearest neighbor, CatBoost, random forest, and XGBoost) with the traditional global (GRACE) risk score for acute coronary event registrations. We registered patients aged >18 years diagnosed with STEMI and hyperuricemia at the Affiliated Hospital of Zunyi Medical University between January 2016 and January 2020. Overall, 656 patients were enrolled (average age, 62.5 ± 13.6 years; 83.6%, male). All patients underwent emergency percutaneous coronary intervention. We evaluated the performance of five machine learning classifiers and the GRACE risk model in predicting 1-year mortality. The area under the curve (AUC) of the six models, including the GRACE risk model, ranged from 0.75 to 0.88. Among all the models, CatBoost had the highest predictive accuracy (0.89), AUC (0.87), precision (0.84), and F1 value (0.44). After hybrid sampling technique optimization, CatBoost had the highest accuracy (0.96), AUC (0.99), precision (0.95), and F1 value (0.97). Machine learning algorithms, especially the CatBoost model, can accurately predict the mortality associated with STEMI complicated by hyperuricemia after a 1-year follow-up.

Dual-peak long period fiber grating coated with graphene oxide for label-free and specific assays of H5N1 virus.

Avian influenza is an acute infectious disease caused by the avian influenza virus (AIV), which has caused enormous economic losses and posed considerable threats to public health. This study aimed to demonstrate an immunosensor based on dispersion turning point long-period fiber grating (DTP-LPFG) integrated with graphene oxide (GO) for the specific detection of a type of AIV H5N1 virus. LPFG was designed to work at DTP, whose dual-peak spacing was very high sensitive to a refractive index. Anti-H5N1 monoclonal antibodies were covalently bonded with the GO film on the fiber surface, thus constructing an immunosensor for the label-free and specific detection of the H5N1 virus. The proposed method was capable of the reliable detection of H5N1 virus with the limit of detection as low as ~1.05 ng/ml within the large range of 1 ng/mL to 25 µg/mL. More importantly, immunoassays of the whole H5N1 virus in clinical samples further confirmed that the GO-integrated DTP-LPFG immunosensor showed very high specificity to the H5N1 virus and demonstrated great potential for clinical use.

CircHIPK3 regulates cardiac fibroblast proliferation, migration and phenotypic switching through the miR-152-3p/TGF-ß2 axis under hypoxia.

BACKGROUND: The occurrence of pathological cardiac fibrosis is attributed to tissue hypoxia. Circular RNAs play significant regulatory roles in multiple cardiovascular diseases and are involved in the regulation of physiological and pathophysiological processes. CircHIPK3 has been identified as the one of the most crucial regulators in cardiac fibrosis. However, the mechanisms by which circHIPK3 regulates cardiac fibrosis under hypoxia remain unclear. Our study aimed to determine circHIPK3 expression in cardiac fibroblasts (CFs) and investigate the functions of circHIPK3 in hypoxia environment. METHODS: The expression level of circHIPK3 in CFs under hypoxia (1% O2) was analyzed by qRT-PCR. The role of circHIPK3 on the proliferation and migration of CFs were determined by EdU, cell wound scratch assay and cell cycle. The expression of proteins associated with phenotypic transformation in CFs in vitro was examined by immunofluorescence assay and western blot. Bioinformatics analysis, dual luciferase activity assay and RNA fluorescent in situ hybridization assay revealed that miR-152-3p was identified as a target of circHIPK3 and that TGF-ß2 was targeted by miR-152-3p. RESULTS: CircHIPK3 expression was significantly upregulated in CFs in a hypoxic environment. In vitro, overexpressing circHIPK3 obviously promoted CF proliferation, migration and phenotypic changes under hypoxia, but those processes were suppressed by circHIPK3 silencing. CircHIPK3 acted as an endogenous miR-152-3p sponge and miR-152-3p aggravated circHIPK3 silencing induced inhibition of CF proliferation, migration, phenotypic transformation and TGF-ß2 expression in vitro. In summary, circHIPK3 plays a pivotal role in the development of cardiac fibrosis by targeting the miR-152-3p/TGF-ß2 axis. CONCLUSIONS: These findings demonstrated that circHIPK3 acted as a miR-152-3p sponge to regulate CF proliferation, migration and phenotypic transformation through TGF-ß2, revealing that modulation of circHIPK3 expression may represent a potential target to promote the transition of hypoxia-induced CFs to myofibroblasts.

Exosomal circHIPK3 Released from Hypoxia-Pretreated Cardiomyocytes Regulates Oxidative Damage in Cardiac Microvascular Endothelial Cells via the miR-29a/IGF-1 Pathway.

BACKGROUND/AIMS: Circular RNAs (circRNAs) are a class of endogenous noncoding RNAs that regulate gene expression in eukaryotes. Recently, exosomes from cardiomyocytes (CMs) have been found to facilitate cell proliferation and survival by transporting various bioactive molecules, including circRNA. However, the functions of exosomal circRNAs are not clear. The present research is aimed at determining whether circHIPK3 released from hypoxia-pretreated CMs is transferred into cardiac microvascular endothelial cells (CMVECs) by exosomes and becomes functionally active in the CMVECs under oxidative stress conditions. METHODS: Quantitative polymerase chain reactions were conducted to detect the expression pattern of circHIPK3 in CMVECs under oxidative stress. Annexin V-FITC/propidium iodide (PI) staining assays, TUNEL assays, ROS assays, and Western blot analysis were conducted to detect the role of exosomal circHIPK3 in CMVEC function in vitro. Luciferase activity assays and RNA immunoprecipitation studies were conducted in vitro to reveal the mechanism of circHIPK3-mediated CMVEC function. RESULTS: circHIPK3 expression was significantly upregulated in hypoxic exosomes (HPC-exos) compared with normoxic exosomes (Nor-exos). Moreover, HPC-exos induced stronger antioxidant effects than Nor-exos. The silencing or overexpression of circHIPK3 changed CMVEC survival under oxidative conditions in vitro. Furthermore, circHIPK3 silencing in HPC-exos abrogated the protective effects of HPC-exos in CMVECs, as shown by increased levels of apoptosis, ROS, MDA, and proapoptotic proteins. circHIPK3 acted as an endogenous miR-29a sponge to sequester and inhibit miR-29a activity, which led to increased IGF-1 expression. The ectopic expression of miR-29a mimicked the effect of circHIPK3 silencing in CMVECs in vitro. CONCLUSIONS: circHIPK3 in HPC-exos plays a role in CMVECs under oxidative conditions through miR-29a-mediated IGF-1 expression, leading to a decrease in oxidative stress-induced CMVECs dysfunction. These data suggest that the exosomal circRNA in CMs is a potential target to control CMVECs dysfunction under oxidative conditions.

Cholesterol induces dedifferentiation of vascular smooth muscle cells by regulating monocyte chemotactic protein-1-induced protein 1.

OBJECTIVE: To discover the effect of cholesterol on dedifferentiation of VSMCs in vitro and the underlying mechanisms. METHODS: Vascular smooth muscle cells (VSMC) were employed to evaluate the role of cholesterol in regulating the dedifferentiation of VSMCs in vitro. Immunofluorescent staining, western blot, and RT-PCR were applied to uncover the inducing effect of cholesterol at a molecular level. RESULTS: We demonstrated that the cholesterol was capable of inducing the dedifferentiation of VSMCs. Mechanistic studies revealed that monocyte chemotactic protein-1-induced protein 1 (MCPIP1) composed the most influential factor in the regulation of VSMCs during the process of cholesterol induction. When MCPIP1 was overexpressed in VSMCs, the dedifferentiation, proliferation and migration of the cells was enhanced, and the expression of miR-145 was suppressed. In contrast, knocking down MCPIP1 by siRNA promoted the differentiation and prohibited the migration of VSMCs after cholesterol treatment. These results demonstrate that MCPIP1 plays an important role in regulating cholesterol-induced dedifferentiation of VSMCs in vitro.

Fluorescence detection and removal of copper from water using a biobased and biodegradable 2D soft material.

We have developed a green and robust fluorogenic (λex = 410 nm, λem = 510 nm) cellulose membrane using graphene oxide (GO) as a construct for simultaneous copper ion recognition and filtration at environmentally relevant levels. The detection limit and removal limit of Cu2+ are 7.3 × 10-7 M and 1000 ppm, respectively. The simplicity and scalability achieved for the detection and removal of metal ions in waste water is particularly noteworthy given the significant problems associated with metal ion pollution of drinking water.

miR-21 Reduces Hydrogen Peroxide-Induced Apoptosis in c-kit+ Cardiac Stem Cells In Vitro through PTEN/PI3K/Akt Signaling.

The low survival rate of cardiac stem cells (CSCs) in the infarcted myocardium hampers cell therapy for ischemic cardiomyopathy. MicroRNA-21 (miR-21) and one of its target proteins, PTEN, contribute to the survival and proliferation of many cell types, but their prosurvival effects in c-kit+ CSC remain unclear. Thus, we hypothesized that miR-21 reduces hydrogen peroxide- (H2O2-) induced apoptosis in c-kit+ CSC and estimated the contribution of PTEN/PI3K/Akt signaling to this oxidative circumstance. miR-21 mimics efficiently reduced H2O2-induced apoptosis in c-kit+ CSC, as evidenced by the downregulation of the proapoptosis proteins caspase-3 and Bax and upregulation of the antiapoptotic Bcl-2. In addition, the gain of function of miR-21 in c-kit+ CSC downregulated the protein level of PTEN although its mRNA level changed slightly; in the meantime, miR-21 overexpression also increased phospho-Akt (p-Akt). The antiapoptotic effects of miR-21 were comparable with Phen (bpV), the selective inhibitor of PTEN, while miR-21 inhibitor or PI3K's inhibitor LY294002 efficiently attenuated the antiapoptotic effect of miR-21. Taken together, these results indicate that the anti-H2O2-induced apoptosis effect of miR-21 in c-kit+ CSC is contributed by PTEN/PI3K/Akt signaling. miR-21 could be a potential molecule to facilitate the c-kit+ CSC therapy in ischemic myocardium.

[Research Progress on Forensic Entomotoxicology].

Forensic entomotoxicology is a branch of forensic medicine, which applies entomology, toxicology and other related studies to solve the poisoning cases. It has an obvious advantage in the investigation on poisoning death. Based on the expounding definition and research of entomotoxicology, this paper reviews research progress and application value in some aspects of forensic medicine, such as the effects of drugs/toxins on the growth and development of sarcosaphagous insects and the qualitative and quantitative analysis of the drugs/toxins in the poisoned body tissue.

[Expression of SDF-1/CXCR4 in acute infarct myocardium after implantation of bone marrow mesenchymal stem cells in rats].

OBJECTIVE: To explore the role of stromal cell derived factor-1 (SDF-1)/CXCR4 axis in acute infarct myocardium after an implantation of bone marrow mesenchymal stem cells (MSCs) in rats. METHODS: The animals were anesthetized by an intraperitoneal injection of pentobarbital sodium. Left anterior thoracotomy through 3/4 intercostals region was performed and then left anterior descending coronary arteries were ligated for modeling acute myocardial infarction. The MSCs were injected into the area of acute infarct myocardium after a 10-minute ligation of left anterior descending coronary artery. The different concentration and expression of SDF-1/CXCR4 in the area of acute myocardial infarction and left ventricular function were analyzed. RESULTS: At day 28 post-transplantation, the vascular density in MSCs implant group were significantly higher than that in control group (P<0.05). And left ventricular function in MSCs implant group improved significantly than that in control group too (P<0.05). At the same time, the expressions of SDF-1 and CXCR4 in topical injection sites of infarct myocardium were significantly higher than those in control group (P<0.05). In MSCs implant group, the level of SDF-1/CXCR4 peaked at Day 1 post-transplantation and then it declined. CONCLUSIONS: After the implantation of MSCs into acute infarct myocardium, there is vascular regeneration and the level of SDF-1/CXCR4 increases so that left ventricular function improves. And the mechanism may be due to an up-regulation of SDF-1/CXCR4 axis.

Transplantation of mesenchymal stem cells carrying the human receptor activity-modifying protein 1 gene improves cardiac function and inhibits neointimal proliferation in the carotid angioplasty and myocardial infarction rabbit model.

Although transplanting mesenchymal stem cells (MSCs) can improve cardiac function and contribute to endothelial recovery in a damaged artery, natural MSCs may induce neointimal hyperplasia by directly or indirectly acting on vascular smooth muscle cells (VSMCs). Receptor activity-modifying protein 1 (RAMP1) is the component and the determinant of ligand specificity of calcitonin gene-related peptide (CGRP). It is recently reported that CGRP and its receptor involve the proliferation and the apoptosis in vivo and in vitro, and the exogenous RAMP1 enhances the antiproliferation effect of CGRP in VSMCs. Here, we investigated the effects of MSCs overexpressing the human receptor activity-modifying protein 1 (hRAMP1) on heart function and artery repair in rabbit models of myocardial infarction (MI) reperfusion and carotid artery injury. MSCs transfected with a recombinant adenovirus containing the hRAMP1 gene (EGFP-hRAMP1-MSCs) were injected into the rabbit models via the ear vein at 24 h after carotid artery injury and MI 7 days post-EGFP-hRAMP1-MSC transplantation. The cells that expressed both enhance green fluorescent protein (EGFP) and CD31 were detected in the neointima of the damaged artery via immunofluorescence. EGFP-hRAMP1 expression was observed in the injured artery and infarcted myocardium by western blot analysis, confirming that the engineered MSCs targeted the injured artery and infarcted myocardium and expressed hRAMP1 protein. Compared with the EGFP-MSCs group, the EGFP-hRAMP1-MSCs group had a significantly smaller infarcted area and improved cardiac function by 28 days after cell transplantation, as detected by triphenyltetrazolium chloride staining and echocardiography. Additionally, arterial hematoxylin-eosin staining revealed that the area of the neointima and the area ratio of intima/media were significantly decreased in the EGFP-hRAMP1-MSCs group. An immunohistological study showed that the expression of α-smooth muscle antigen and proliferating cell nuclear antigen in the neointima cells of the carotid artery of the EGFP-hRAMP1-MSCs group was approximately 50% lower than that of the EGFP-MSCs group, suggesting that hRAMP1 expression may inhibit VSMCs proliferation within the neointima. Therefore, compared with natural MSCs, EGFP-hRAMP1-engineered MSCs improved infarcted heart function and endothelial recovery from artery injury more efficiently, which will provide valuable information for the development of MSC-based therapy.

[Effects of CGRP and CGRP receptor modified mesenchymal stem cells on proliferation and phenotypic transformation of vascular smooth muscle cells].

OBJECTIVE: To explore the effects and mechanism of secretory calcitonin gene-related peptide (CGRP) and CGRP receptor modified mesenchymal stem cells on proliferation and phenotypic transformation of vascular smooth muscle cell. METHODS: Firstly (Lenti-GFP-CGRP, referred to CGRP (+/+)) MSCs were transfected with high expression lentivirus vector of CGRP (MSCs(CGRP+/+)). Protein secretion in the above-mentioned MSCs(CGRP+/+) supernatant was detected with enzyme-linked immunosorbent assay (ELISA). And then MSCs(CGRP+/+) was co-cultured with VSMCs(RAMP1)(+/+) and VSMCs(RAMP1-/-) respectively. Experimental groups were as follows: MSCs +VSMCs MSCs(CGRP+/+) +VSMCs, MSCs(CGRP+/+) +VSMCs(RAMP1)(+/+) and MSCs(CGRP+/+) + VSMCs (RAMP1-/-). Flow cytometry was applied to detect the cycle variation of smooth muscle cells, thiazolyl blue tetrazolium bromide method for detecting the proliferation of smooth muscle cells and Western blot for examining the expression changes of spectrin α-SM-actin and synthetic protein OPN in each group respectively. RESULTS: After the transfection of CGRP(+/+), MSCs(CGRP+/+) secreted and expressed CGRP protein, the secretory volume of CGRP protein in MSCs(CGRP+/+) increased significantly compared with the control group (19.530 ± 0.498 vs 3.133 ± 0.160 and 3.120 ± 0.001, P < 0.05) . After a 72 h co-culturing with VSMCs, the proliferation of VSMCs in MSCs(CGRP+/+) +VSMCs(RAMP1)(+/+)group declined significantly (0.270 ± 0.263 vs 0.413 ± 0.070, P < 0.05) and the number of cells staying in G0 phase significantly increased (93.51% ± 0.38% vs 84.48% ± 0.31%, P < 0.05) , the expression of contractile phenotype protein α-SM-actin increased and intermediate phenotype OPN declined significantly as compared with MSCsCGRP(+/+) +VSMCs group { (α-SM-actin 102 946 ± 3847 vs 51 759 ± 635, P < 0.05), OPN (26 026 ± 2595 vs 44 201 ± 2811, P < 0.05) }; but compared with MSCs(CGRP+/+)+VSMCs(RAMP1)(+/+)group, the proliferation of VSMCs in MSCs(CGRP+/+) +VSMCs(RAMP1)-/-group significantly increased (0.601 ± 0.04 vs 0.270 ± 0.263, P < 0.05) while the number of cells staying in G0 phase significantly declined (78.57% ± 0.68% vs 93.51% ± 0.38%, P < 0.05) . The expression of contractile phenotype protein α-SM-actin declined while intermediate phenotype OPN increased significantly in MSCs(CGRP+/+)+VSMCs(RAMP1)-/-group {α-SM-actin (34 400 ± 2179 vs 102 946 ± 3847, P < 0.05), OPN (53 933 ± 1192 vs 26 026 ± 2595, P < 0.05)}. CONCLUSIONS: CGRP gene-modified MSCs may secrete target protein stably. And CGRP-modified MSCs inhibits VSMCs phenotypic transformation and cell proliferation. It is probably associated with enhanced CGRP effect due to an up-regulation of CGRP receptor.