Association between lactate/albumin ratio and prognosis in patients with acute myocardial infarction.

BACKGROUND: The association between the lactate/albumin ratio (L/A) as a diagnostic indicator and unfavourable clinical outcomes has been established in patients with community-acquired pneumonia, sepsis and heart failure, but the connection between L/A and all-cause mortality in patients with acute myocardial infarction (AMI) has yet to be fully understood. METHODS: This was a retrospective cohort study using MIMIC-IV (v2.2) data, with 2816 patients enrolled and all-cause mortality during hospitalization as the primary outcome. Kaplan-Meier (KM) analysis was used to compare the all-cause mortality between high-level and low-level L/A groups. Receiver operating characteristic (ROC) curve, Restricted cubic splines (RCS) and Cox proportional hazards analysis were performed to investigate the relationship between L/A ratio and in-hospital all-cause mortality. RESULTS: L/A values were significantly higher in the non-survivor groups than the survival groups (1.14 [.20] vs. .60 [.36], p < .05), and area under the ROC curve [.734 (95% confidence interval, .694-.775)] was better than other indicators. Data of COX regression analysis showed that higher L/A value supposed to be an independent risk factor for in-hospital mortality. RCS analysis showed evidence of an increasing trend and a non-linear relationship between L/A and in-hospital mortality (p-value was non-linear <.05). KM survival curves were significantly lower in the high L/A group than the low L/A group (p < .001), and the former group had an increased risk of in-hospital mortality compared with the latter one (Log Rank p < .001). CONCLUSIONS: L/A demonstrates significant independent predictive power for elevated all-cause mortality during hospitalization in patients diagnosed with AMI.

Cardiac Nestin+ Mesenchymal Stromal Cells Enhance Healing of Ischemic Heart through Periostin-Mediated M2 Macrophage Polarization.

Mesenchymal stromal cells (MSCs) show potential for treating cardiovascular diseases, but their therapeutic efficacy exhibits significant heterogeneity depending on the tissue of origin. This study sought to identify an optimal source of MSCs for cardiovascular disease therapy. We demonstrated that Nestin was a suitable marker for cardiac MSCs (Nes+cMSCs), which were identified by their self-renewal ability, tri-lineage differentiation potential, and expression of MSC markers. Furthermore, compared with bone marrow-derived MSCs (Nes+bmMSCs) or saline-treated myocardial infarction (MI) controls, intramyocardial injection of Nes+cMSCs significantly improved cardiac function and decreased infarct size after acute MI (AMI) through paracrine actions, rather than transdifferentiation into cardiac cells in infarcted heart. We further revealed that Nes+cMSC treatment notably reduced pan-macrophage infiltration while inducing macrophages toward an anti-inflammatory M2 phenotype in ischemic myocardium. Interestingly, Periostin, which was highly expressed in Nes+cMSCs, could promote the polarization of M2-subtype macrophages, and knockdown or neutralization of Periostin remarkably reduced the therapeutic effects of Nes+cMSCs by decreasing M2 macrophages at lesion sites. Thus, the present work systemically shows that Nes+cMSCs have greater efficacy than do Nes+bmMSCs for cardiac healing after AMI, and that this occurs at least partly through Periostin-mediated M2 macrophage polarization.

Cardiac Nestin+ Cells Derived from Early Stage of Dilated Cardiomyopathy Enhanced the Survival of the Doxorubicin-Injured Cardiac Muscle HL-1 Cells.

Dilated cardiomyopathy (DCM), as one of the common cardiomyopathies, is a disease of the heart muscle; however, the etiology and pathogenesis of DCM were still poorly understood. Nestin has been reported a special marker of stem/progenitor cells in various tissues, and the tissue resident Nestin+ cells could promote the wound healing and tissue remodeling. However, it remains unclear whether Nestin+ cells participate in the protection of cardiomyocytes during the pathogenesis of DCM. Here the model of mice DCM was induced by doxorubicin (DOX) intraperitoneal injection and observed heart failure and ventricular enlargement via echocardiography and histologic analysis, respectively. During DCM pathogenesis, the number of Nestin+ cells showed a significant peak on day 6 after DOX treatment, which then gradually decreases to lower than normal levels after day 30 in the total population of the heart. Furthermore, we found that the isolated increased heart-derived Nestin+ cells are mesenchymal property and could protect DOX-induced HL-1 cells toxicity in vitro by promoting their proliferation and inhibiting their apoptosis. Collectively, our results showed that Nestin+ cells increased during DCM pathogenesis and played an important role in protecting against the DOX-induced HL-1 cells loss via regulating proliferation and apoptosis. Thus, the loss of Nestin+ cells might be an etiology to DCM pathogenesis, and these cells could be a promising candidate cell source for study and treatment of DCM patients.

Impact of lactate/albumin ratio on prognostic outcomes in patients with concomitant heart failure and chronic kidney disease.

Previous studies have linked the lactate/albumin (L/A) ratio to poor outcomes in various conditions, but its connection to mortality in patients with both heart failure (HF) and chronic kidney disease (CKD) remains unclear. Using data from 1537 patients in MIMIC-IV, this study examined the relationship between L/A ratio and in-hospital and one-year mortality, employing Cox models, Kaplan-Meier (KM) analysis, and restricted cubic splines (RCS). The non-survivor group showed higher L/A ratios than survivors (1.04 ± 0.78 vs. 0.58 ± 0.29, p < 0.001), indicating a significant link between higher L/A ratios and mortality. Cox analysis identified the L/A ratio was significantly related to all-cause mortality both in-hospital (HR 2.033; 95% CI 1.576-2.624; p < 0.001) and one-year (HR 1.723; 95% CI 1.428-2.078; p < 0.001). The association between L/A ratio and mortality was non-linear and increasing. The KM survival curves demonstrated significantly poorer survival outcomes for the high L/A group compared to the low L/A group, a difference that was statistically validated by a significant log-rank test (log-rank p < 0.001). L/A ratio has a significant association with poor prognosis in patients with HF and CKD patients in a critical condition. This finding demonstrates that L/A ratio might be useful in identifying patients with HF and CKD at high risk of all-cause death. Further large-scale prospective studies are needed to verify these results and inform clinical decisions.

Triglyceride-glucose index and prognosis in individuals afflicted with heart failure and chronic kidney disease.

BACKGROUND: The triglyceride-glucose (TyG) index has demonstrated correlations with adverse clinical outcomes in patients with ischaemic stroke, coronary heart disease and cardiac failure. However, its association with overall mortality in individuals concurrently experiencing heart failure (HF) and chronic kidney disease (CKD) remains inadequately explored. METHODS: Utilizing the Medical Information Mart for Intensive Care IV (Version 2.2) repository, subjects underwent quartile stratification based on the TyG index. The primary endpoint was all-cause mortality during hospitalization. Cox proportional hazard models were employed to examine the correlation between TyG and all-cause mortality in HF patients with CKD. Evaluation involved Kaplan-Meier (KM) analysis and restricted cubic splines (RCSs) to compare mortality rates during hospitalization and 1 year after admission across cohorts with varying TyG index levels. RESULTS: A cohort of 1537 HF and CKD patients participated. Cox regression analysis revealed elevated TyG levels as an independent risk factor for both in-hospital and 1 year mortality. RCS analysis indicated a rising, non-linear association between TyG levels and all-cause mortality (P value for non-linear <0.001). KM survival curves demonstrated a statistically significant reduction in survival rates within the high TyG index group compared with the low one (log-rank P < 0.001). CONCLUSIONS: The TyG index exhibited substantial independent prognostic value for elevated in-hospital and 1 year all-cause mortality among the cohort with HF and CKD. These findings suggest that assessing the TyG index could play a crucial role in developing novel therapeutic strategies to improve outcomes for this high-risk demographic.

Alpha lipoic acid-loaded electrospun fibrous patch films protect heart in acute myocardial infarction mice by inhibiting oxidative stress.

Oxidative stress, characterized by excessive accumulation of reactive oxygen species (ROS), is involved in acute myocardial infarction (AMI)-related pathological processes and vascular reperfusion therapy injury. Alpha lipoic acid (LA) exhibits excellent antioxidant properties, however, its application is limited by inherent characteristics, including rapid clearance and extensive volume distribution. In this study, we hypothesized that scavenging cardiac ROS using adequately delivered LA could promote heart repair. Here, we report a new strategy for dynamic-release LA to treat AMI disease. In particular, this involves using poly(lactic-co-glycolic) (PLGA) copolymers as carriers to form a thin film (LA@PLGA) via electrospinning technology to achieve controlled release of LA, which essentially blocking local ROS production in damaged hearts. The drug-loading capacity and capsulation efficiency of this compound film could be regulated by determining the dose proportions of LA and PLGA. The incubation of LA@PLGA showed strong anti-oxidative activity and anti-apoptosis effect in hydrogen peroxide-administered primary cardiomyocytes. Patching LA@PLGA on the infarcted cardiac surfaces of AMI mice dramatically improved heart functions and reduced cardiac fibrosis throughout ventricular remodeling process. Importantly, the attenuation of detrimental pathologies was observed, including oxidative stress, senescence, DNA damage, cytokine-related processes, apoptosis, and ferroptosis. These results suggest that PLGA-carried LA can reduce ROS damage and restore heart function after myocardial damage, demonstrating a great potential for LA drugs in treating AMI disease.

Association between lactate/albumin ratio and mortality in patients with heart failure after myocardial infarction.

AIMS: Lactate/albumin ratio (L/A) is a recognized prognostic index of patients with heart failure (HF) after myocardial infarction (MI). We aim to evaluate the prognostic value of L/A ratio in predicting in-hospital mortality for those patients. METHODS AND RESULTS: We enrolled qualified patients from Medical Information Mart for Intensive Care IV database for retrospective study. A receiver operating characteristic (ROC) curve of the subjects was applied to determine the predicted value and the best cut-off value of L/A on admission. Univariate/multivariate Cox regression analysis and restricted cubic splines (RCS) were performed to identify the association between hospital admission and hospital mortality. The Kaplan-Meier (KM) method was used to draw the survival curve of the two groups with different L/A levels at admission. L/A values at admission were significantly higher in the death groups than the survival groups [1.36 (1.20) vs. 0.62 (0.36), P < 0.05], and area under the ROC curve [0.780 (95% confidence interval, 0.772-0.827)] was better than other indicators, and the best the cut-off value was 0.671. Data of Cox regression analysis showed that higher L/A value supposed to be an independent risk factor for in-hospital mortality. RCS analysis showed evidence of an increasing trend and a non-linear relationship between L/A and in-hospital mortality (P value was non-linear <0.05). KM survival curves were significantly lower in the high L/A group than the low L/A group (P < 0.001), and the former group had an increased risk of in-hospital mortality compared with the latter one (log rank P < 0.001). CONCLUSIONS: Elevated L/A ratio on admission is an independent predictor of high in-hospital mortality in post-MI heart failure patients, which proved to be better than lactate, Sequential Organ Failure Assessment score and other related indicators.

Metformin attenuates ventricular hypertrophy by activating the AMP-activated protein kinase-endothelial nitric oxide synthase pathway in rats.

1. Metformin is an activator of AMP-activated protein kinase (AMPK). Recent studies suggest that pharmacological activation of AMPK inhibits cardiac hypertrophy. In the present study, we examined whether long-term treatment with metformin could attenuate ventricular hypertrophy in a rat model. The potential involvement of nitric oxide (NO) in the effects of metformin was also investigated. 2. Ventricular hypertrophy was established in rats by transaortic constriction (TAC). Starting 1 week after the TAC procedure, rats were treated with metformin (300 mg/kg per day, p.o.), N(G)-nitro-L-arginine methyl ester (L-NAME; 50 mg/kg per day, p.o.) or both for 8 weeks prior to the assessment of haemodynamic function and cardiac hypertrophy. 3. Cultured cardiomyocytes were used to examine the effects of metformin on the AMPK-endothelial NO synthase (eNOS) pathway. Cells were exposed to angiotensin (Ang) II (10⁻6 mol/L) for 24 h under serum-free conditions in the presence or absence of metformin (10⁻³ mol/L), compound C (10⁻6 mol/L), L-NAME (10⁻6 mol/L) or their combination. The rate of incorporation of [³H]-leucine was determined, western blotting analyses of AMPK-eNOS, neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) were undertaken and the concentration of NO in culture media was determined. 4. Transaortic constriction resulted in significant haemodynamic dysfunction and ventricular hypertrophy. Myocardial fibrosis was also evident. Treatment with metformin improved haemodynamic function and significantly attenuated ventricular hypertrophy. Most of the effects of metformin were abolished by concomitant L-NAME treatment. L-NAME on its own had no effect on haemodynamic function and ventricular hypertrophy in TAC rats. 5. In cardiomyocytes, metformin inhibited AngII-induced protein synthesis, an effect that was suppressed by the AMPK inhibitor compound C or the eNOS inhibitor L-NAME. The improvement in cardiac structure and function following metformin treatment was associated with enhanced phosphorylation of AMPK and eNOS and increased NO production. 6. The findings of the present study indicate that long-term treatment with metformin could attenuate ventricular hypertrophy induced by pressure overload via activation of AMPK and a downstream signalling pathway involving eNOS-NO.

Adipose mesenchymal stem cells and gingival mesenchymal stem cells have a comparable effect in endothelium repair.

Restenosis is the major factor influencing the long-term success rate of angioplasty and stent implantation and effective strategies to prevent restenosis remain limited. Mesenchymal stem cells (MSCs) are pluripotent stem cells capable of self-renewal and multidirectional differentiation, which may be able to promote endothelium repair, thereby reducing restenosis. The present study aimed to evaluate the effects of adipose MSCs (AMSCs) and gingival MSCs (GMSCs) on endothelium repair. MSCs were isolated from two human tissue types, namely adipose tissue and gingival tissue, and the effects of AMSCs and GMSCs in ex vivo endothelium repair and on vascular smooth muscle cell (SMC) growth were examined. To compare the feasibility of using AMSCs and GMSCs for the repair of endothelium damage in endothelial cell (EC) damage and vasoproliferative disorders, an ex vivo model of endothelium repair in a co-culture system was developed. It was indicated that AMSCs and GMSCs expressed characteristic MSC markers (CD105 and CD166). 3H-thymidine incorporation in the co-culture group of AMSCs and SMCs in the presence of ECs was lower compared with that in the GMSC and SMC co-culture group. The protein expression level of proliferating cell nuclear antigen in the co-culture group of AMSCs and SMCs in the presence of ECs were lower compared with that in the GMSC and SMC co-culture group. After co-culture with ECs for 5 days, 25.71±3.08% of AMSCs began to express CD31 protein and 20.06±2.09% of GMSCs began to express CD31 protein. Furthermore, anti-VEGF antibody was able to inhibit MSC differentiation. Collectively, the present results suggested that seeding of AMSCs had a stronger effect to inhibit the proliferation and migration of SMCs compared with GMSCs.

Cardiac Derived CD51-Positive Mesenchymal Stem Cells Enhance the Cardiac Repair Through SCF-Mediated Angiogenesis in Mice With Myocardial Infarction.

Objective: Many tissues contained resident mesenchymal stromal/stem cells (MSCs) that facilitated tissue hemostasis and repair. However, there is no typical marker to identify the resident cardiac MSCs. We aimed to determine if CD51 could be an optimal marker of cardiac MSCs and assess their therapeutic potential for mice with acute myocardial infarction (AMI). Methods: Cardiac-derived CD51+CD31-CD45-Ter119- cells (named CD51+cMSCs) were isolated from C57BL/6 mice(7-day-old) by flow cytometry. The CD51+cMSCs were characterized by proliferation capacity, multi-differentiation potential, and expression of typical MSC-related markers. Adult C57BL/6 mice (12-week-old) were utilized for an AMI model via permanently ligating the left anterior descending coronary artery. The therapeutic efficacy of CD51+cMSCs was estimated by echocardiography and pathological staining. To determine the underlying mechanism, lentiviruses were utilized to knock down gene (stem cell factor [SCF]) expression of CD51+cMSCs. Results: In this study, CD51 was expressed in the entire layers of the cardiac wall in mice, including endocardium, epicardium, and myocardium, and its expression was decreased with age. Importantly, the CD51+cMSCs possessed potent self-renewal potential and multi-lineage differentiation capacity in vitro and also expressed typical MSC-related surface proteins. Furthermore, CD51+cMSC transplantation significantly improved cardiac function and attenuated cardiac fibrosis through pro-angiogenesis activity after myocardial infarction in mice. Moreover, SCF secreted by CD51+cMSCs played an important role in angiogenesis both in vivo and in vitro. Conclusions: Collectively, CD51 is a novel marker of cardiac resident MSCs, and CD51+cMSC therapy enhances cardiac repair at least partly through SCF-mediated angiogenesis.

Upregulation of MicroRNA-125b Leads to the Resistance to Inflammatory Injury in Endothelial Progenitor Cells.

OBJECTIVES: MicroRNA-125b (miR-125b) has been recognized as one of the key regulators of the inflammatory responses in cardiovascular diseases recently. This study sought to dissect the role of miR-125b in modulating the function of endothelial progenitor cells (EPCs) in the inflammatory environment of ischemic hearts. METHODS: EPCs were cultured and transfected with miR-125b mimic and negative control mimic. Cell migration and adhesion assays were performed after tumor necrosis factor-α (TNF-α) treatment to determine EPC function. Cell apoptosis was analyzed by flow cytometry. The activation of the NF-κB pathway was measured by western blotting. EPC-mediated neovascularization in vivo was studied by using a myocardial infarction model. RESULTS: miR-125b-overexpressed EPCs displayed improved cell migration, adhesion abilities, and reduced cell apoptosis compared with those of the NC group after TNF-α treatment. miR-125b overexpression in EPCs ameliorated TNF-α-induced activation of the NF-κB pathway. Mice transplanted with miR-125b-overexpressed EPCs showed improved cardiac function recovery and capillary vessel density than the ones transplanted with NC EPCs. CONCLUSIONS: miR-125b protects EPCs against TNF-α-induced inflammation and cell apoptosis by attenuating the activation of NF-κB pathway and consequently improves the cardiac function recovery and EPC-mediated neovascularization in the ischemic hearts.

Protective effect of bone marrow mesenchymal stem cell-derived exosomes on cardiomyoblast hypoxia-reperfusion injury through the miR-149/let-7c/Faslg axis.

Ischaemia-reperfusion injury (IRI) is closely related to cardiovascular disease (CVD), which is the leading cause of death and disability. Exosomes appear to be involved in several diseases, including CVD. However, the role of mesenchymal stem cell (MSC)-derived exosomes in IRI remains unclear. miRNA expression levels in exosomes from rat normal MSCs or hypoxia-reoxygenation (H/R) MSCs were determined by qPCR and the two significantly upregulated miRNAs were selected for further investigation. Rat cardiomyoblasts (H9c2) were transfected with either miRNA mimics or scramble controls, followed by H/R induction. The effects of miRNA overexpression and exosome administration on H/R damage were then investigated. H/R increased Faslg, suppressed ß-catenin, inhibited cell proliferation and migration, and stimulated apoptosis and reactive oxygen species (ROS) production. miR-149 or Let-7c mimics or exosomes reversed H/R-induced damage. The luciferase reporter assay proved the targeted regulation of Faslg by both miR149 and Let-7c. Inhibition of ß-catenin suppressed cell migration, proliferation, and ΔΨm but increased apoptosis and ROS. Overall, bone marrow MSC-derived exosomes protected rat cardiomyoblasts from H/R injury via the miR-149/Let-7c/Faslg axis.

[Association between hemoglobin scavenger receptor CD163 expression and coronary atherosclerotic severity in patients with coronary heart disease].

OBJECTIVE: To investigate the association between hemoglobin scavenger receptor (CD163) expression levels on monocytic surfaces and coronary atherosclerotic severity in patients with coronary heart disease (CHD) as well as the roles of CD163 in inflammation and lipidperoxidation. METHODS: Eighty-four patients were diagnosed as CHD according to the results of coronary angiography and ACC/AHA diagnostic criteria. The patients were divided into 3 groups: acute myocardial infarction (AMI) group (n = 30), unstable angina (UA) group (n = 30), stable angina (SA) group (n = 24). Another 20 patients with normal coronary artery served as control. Expression levels of CD163 on monocytes were detected by means of flow cytometry, and the results were shown as mean fluorescence intensity (mfi). All patients underwent coronary angiography and the results were further evaluated by Jenkins score. Serum CRP and LDL-C were also measured. RESULTS: The expression levels of CD163 on monocytes in peripheral blood were significantly higher in CHD patients compared to controls (P < 0.01) in the order of AMI group [(84.4 +/- 6.9) mfi] > UA group [(64.1 +/- 5.5) mfi, P < 0.01 vs. AMI] > SA group [(46.7 +/- 6.5) mfi, P < 0.01 vs. AMI and UA] > control group [(22.0 +/- 6.1) mfi, P < 0.01 vs. AMI, UA and SA]. The expression levels of CD163 on monocytes in patients with CHD were positively correlated with Jenkins score (r = 0.9107, P < 0.01), CRP (r = 0.766, P < 0.01) and LDL-C (r = 0.749, P < 0.01). CONCLUSIONS: Expression levels of CD163 was significantly increased in patients with CHD and positively correlated with coronary heart disease severity and serum CRP and LDL-C.

Long noncoding RNA-MEG3 contributes to myocardial ischemia-reperfusion injury through suppression of miR-7-5p expression.

Long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) plays an important role in protection of ischemia-reperfusion (I/R) injury in brain and liver. However, role of MEG3 in myocardial I/R injury remains unclear. Here, the role of MEG3 in protection of myocardial I/R injury and its association with microRNA-7-5p (miR-7-5p) was investigated using rat cardiac I/R model and myocardial I/R cell model. Our results showed that MEG3 was significantly up-regulated and miR-7-5p was significantly down-regulated after I/R. Following I/R, the levels of intact PARP and intact caspase-3 were reduced, while the cleaved fragments of PARP and caspase-3 were increased. TUNEL assay showed an increase in cardiomyocyte apoptosis after I/R. The levels of I/R-induced creatine kinase (CK) and lactate dehydrogenase (LDH) were inhibited by knockdown of MEG3 (siMEG3). SiMEG3 increased cell proliferation and inhibited cell apoptosis after I/R. In contrast, overexpression of MEG3 increased the I/R-induced CK and LDH activities and cell apoptosis and decreased cell proliferation. The dual-luciferase reporter system showed a direct binding of MEG3 to miR-7-5p. The level of miR-7-5p was negatively associated with the change in levels of MEG3 in H9c2 cells. The levels of intact RARP1 and caspase-3 were significantly increased by knockdown of MEG3. Co-transfection of miR-7-5p inhibitor with siMEG3 activates CK and LDH, significantly decreased cell proliferation, increased cell apoptosis, and decreased intact poly(ADP-ribose) polymerase 1 (PARP1) and caspase-3. In summary, down-regulation of MEG3 protects myocardial cells against I/R-induced apoptosis through miR-7-5p/PARP1 pathway, which might provide a new therapeutic target for treatment of myocardial I/R injury.

Bone marrow mesenchymal stem cell-derived exosomes protect against myocardial infarction by promoting autophagy.

Exosomes have been demonstrated to be effective in the treatment of a variety of cardiac disorders. However, the effects of mesenchymal stem cell (MSC) exosomes on myocardial infarction is yet to be determined. The current study aimed to investigate the potential therapeutic effects of MSC exosomes on myocardial injuries that are caused by myocardial infarction. MSCs were isolated from rat bone marrow and were used for exosome enrichment using culture medium. Confirmation that MSCs and exosomes had been successfully extracted was performed using flow cytometry, electron microscopy and western blot analysis. A rat myocardial ischemia reperfusion (I/R) model was established by ligation of the left anterior descending coronary artery. Rat myocardial injuries were determined using 2,3,5-triphenyltetrazolium chloride, Masson and TUNEL staining. H9c2 cell proliferation, apoptosis and migration were analyzed using 5-ethynyl-2'-deoxyuridine, Hoechst staining, flow cytometry and Transwell assays. Marker gene expression was evaluated using reverse transcription-quantitative PCR, western blot analysis and immunofluorescence. Rat MSC exosomes were revealed to suppress myocardial injury and the myocardiocyte functions that were induced by I/R. The results also demonstrated decreased apoptotic protease activating factor-1 and increased autophagy-related protein 13 expression. The H9c2 cell proliferation and migration inhibition, as well as cell apoptosis during hypoxia-reoxygenation (H/R), were suppressed by rat MSC exosomes, with an alteration of the expression of apoptotic and autophagic genes also being demonstrated. The application of autophagy inhibitor 3-methyladenine significantly mitigated the effect of exosomes on H9c2 cell proliferation and apoptosis, which were induced by H/R. Rat MSC exosomes inhibited myocardial infarction pathogenesis, possibly by regulating autophagy.

Effect of potassium supplementation on vascular function: A meta-analysis of randomized controlled trials.

BACKGROUND: Effects of potassium supplementation on vascular function remain conflicting. This meta-analysis aimed to summarized current literature to fill the gaps in knowledge. METHODS: A literature search was performed on PubMed database through April, 2016. The measurements of vascular function included pulse wave velocity (PWV), augmentation index (AI), pulse pressure (PP), flow mediated dilatation (FMD), glycerol trinitrate responses (GTN), and intercellular cell adhesion molecule-1 (ICAM-1). Data were pooled as standardized mean difference (SMD) with 95% confidence intervals. RESULTS: Seven randomized controlled trials examining 409 participants were included, with dosage of potassium ranging from 40 to 150mmol/day, and duration of intervention from 6days to 12months. Pooling results revealed a significant improvement in PP (SMD -0.280, 95% CI -0.493 to -0.067, p=0.010), but no improvement in PWV (SMD -0.342, 95% CI -1.123 to 0·440, p=0.391), AI (SMD -0.114, 95% CI -0.282 to 0.054, p=0.184), FMD (SMD 0·278, 95% CI -0.321 to 0.877, p=0.363), GTN (SMD -0.009, 95% CI -0.949 to 0.930, p=0.984), and ICAM-1 (SMD -0.238, 95% CI -0.720 to 0.244, p=0.333). CONCLUSIONS: Potassium supplementation was associated with significant improvement of PP, rather than other measurements of vascular function. However, the small number of researches and wide variation of evidences make it difficult to make a definitive conclusion.

Effect of transplantation with autologous bone marrow stem cells on acute myocardial infarction.

BACKGROUND: This study was designed to investigate the effects of treatment with autologous mesenchymal stem cells (MSCs) by intracoronary transplantation on myocardial infarction (MI) in swine. METHODS: MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labeled in vitro with superparamagnetic iron oxide (SPIO). An acute MI (AMI) model was established by percutaneous balloon occlusion. Dual-labeled MSC suspensions were injected through the infarct-related coronary artery using an over-the-wire (OTW) balloon device in the experimental group (n=5), while normal saline was injected into the control (n=5). Stem cell migration and improvements of cardiac function were evaluated by magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and ultrasonic cardiogram (UCG) both before MSC transplantation and after 8 weeks. At 8weeks after transplantation, myocardial tissue was analyzed by histopathologic analyses. RESULTS: Blue SPIO particles were in the cytoplasm of the MSCs. The labeling efficiency reached 100%. MRI revealed hypointensities of SPIO-labeled MSCs that were clustered in the myocardial infarct area after MSC transplantation. As time progressed, the signal gradually weakened and the area shrank. SPECT revealed that the myocardial filling defect was reduced and the amount of surviving myocardium was significantly increased at 8weeks. UCG revealed significant improvement when compared with the control at 8 weeks after transplantation. Prussian blue-positive cells were observed in the MI border zone. Fluorescence-positive cells were also observed, but the number of such cells was fewer than before. CONCLUSIONS: In vivo serial tracking of SPIO-labeled MSCs can be achieved by MRI. Intracoronary transplantation of SPIO-labeled MSCs can increase cardiac function and promote myocardial viability.

Magnetic resonance evaluation of transplanted mesenchymal stem cells after myocardial infarction in swine.

INTRODUCTION: Our objective was to trace and evaluate intracoronary transplanted mesenchymal stem cells (MSCs) labelled with superparamagnetic iron oxide (SPIO) by using magnetic resonance imaging (MRI) in a swine model of myocardial infarction (MI). METHODS: MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labelled in vitro with SPIO. At 2 weeks after MI, swine were randomized to intracoronary transplantation of dual-labelled MSCs (n=10), MSC-GFP (n=10), and saline (n=5). MRI examination was performed with a 1.5-T clinical scanner at 24 hours, 3 weeks, and 8 weeks after cell transplantation. Signal intensity changes, cardiac function, and MI size were measured by means of MRI. The correlation between MRI findings and histomorphologic findings was also investigated. RESULTS: MSCs could be efficiently and safely labelled with SPIO and GFP, and multipotentiality was not affected, especially for cardiomyocyte-like cell differentiation. Signal intensity on T2*-weighted imaging decreased substantially in the interventricular septum 24 hours after injection of MSCs. The intensity of hypointense signals appeared to increase throughout the later time points. Both dual-labelled MSCs and MSC-GFP could dramatically reduce the size of MI and improve cardiac function. Histologic data revealed that cells positive for Prussian blue stain were found mainly in the border zone, which also showed green fluorescence. CONCLUSIONS: In vivo 8-week tracing of dual-labelled MSCs can be achieved by MRI. Intracoronary transplantation of dual-labelled MSCs can increase cardiac function and reduce the size of MI in a swine model.