Direct cardio-protection of Dapagliflozin against obesity-related cardiomyopathy via NHE1/MAPK signaling.

Obesity is an important independent risk factor for cardiovascular diseases, remaining an important health concern worldwide. Evidence shows that saturated fatty acid-induced inflammation in cardiomyocytes contributes to obesity-related cardiomyopathy. Dapagliflozin (Dapa), a selective SGLT2 inhibitor, exerts a favorable preventive activity in heart failure. In this study, we investigated the protective effect of Dapa against cardiomyopathy caused by high fat diet-induced obesity in vitro and in vivo. Cultured rat cardiomyocyte H9c2 cells were pretreated with Dapa (1, 2.5 µM) for 1.5 h, followed by treatment with palmitic acid (PA, 200 µM) for 24 h. We showed that Dapa pretreatment concentration-dependently attenuated PA-induced cell hypertrophy, fibrosis and apoptosis. Transcriptome analysis revealed that inhibition of PA-activated MAPK/AP-1 pathway contributed to the protective effect of Dapa in H9c2 cells, and this was confirmed by anti-p-cJUN fluorescence staining assay. Using surface plasmon resonance analysis we found the direct binding of Dapa with NHE1. Gain and loss of function experiments further demonstrated the role of NHE1 in the protection of Dapa. In vivo experiments were conducted in mice fed a high fat diet for 5 months. The mice were administered Dapa (1 mg·kg-1·d-1, i.g.) in the last 2 months. Dapa administration significantly reduced the body weight and improved the serum lipid profiles. Dapa administration also alleviated HFD-induced cardiac dysfunction and cardiac aberrant remodeling via inhibiting MAPK/AP-1 pathway and ameliorating cardiac inflammation. In conclusion, Dapa exerts a direct protective effect against saturated fatty acid-induced cardiomyocyte injury in addition to the lowering effect on serum lipids. The protective effect results from negative regulating MAPK/AP-1 pathway in a NHE1-dependent way. The current study highlights the potential of clinical use of Dapa in the prevention of obesity-related cardiac dysfunction.

The association of resting postoperative systolic, diastolic, and mean blood pressure and pulse pressure with short- and long-term mortality in patients with acute coronary syndrome undergoing primary percutaneous coronary intervention.

BACKGROUND: Admission blood pressure was closely associated with adverse cardiac events in acute coronary syndrome (ACS) patients. However, data regarding comparison of resting postoperative systolic, diastolic, and mean blood pressure and pulse pressure with short- and long-term mortality in patients with acute coronary syndrome undergoing primary percutaneous coronary intervention (PCI) was still lacking. METHODS: The study analyzed 1987 ACS patients undergoing primary PCI, between January 2014 and October 2018. The primary outcomes were in-hospital cardiac and long-term all-cause mortality. RESULTS: Bar tendency chart and adjusted odds ratios showed that the resting postoperative SBP≤100 mmHg, PP≤30 mmHg and MAP≤70 mmHg have higher in-hospital cardiac (SBP: adjusted OR=9.42, 95% CI: 1.95-45.53, P<0.01; PP: adjusted OR=8.61, 95% CI: 2.53-29.30, P<0.01; MAP: adjusted OR=4.01, 95% CI: 1.61-9.98, P<0.01) and long-term all-cause mortality (SBP: adjusted HR=4.18, 95% CI: 1.43-12.23, P<0.01; PP: adjusted HR=3.71, 95% CI: 1.66-8.24, P<0.01; MAP: adjusted HR=2.54, 95% CI: 1.14-5.65, P<0.01), and the relationship between resting postoperative SBP and in-hospital cardiac or long-term all-cause mortality seemed to follow a J-shaped curve with increased event rates at low and high groups. CONCLUSIONS: The resting postoperative SBP≤100 mmHg, PP≤30 mmHg and MAP≤70 mmHg are independent adverse prognosticators in ACS patients undergoing primary PCI, and the relationship between SBP and mortality looks like a J-shaped curve.

Elevated circulating level of P2X7 receptor is related to severity of coronary artery stenosis and prognosis of acute myocardial infarction.

BACKGROUND: Acute myocardial infarction (AMI) is a severely life-threatening cardiovascular disease. Previous research has identified an association between the P2X7 receptor (P2X7R) and the development of atherosclerosis. However, the correlation of its expression with the clinical prognosis of patients with AMI remains unclear. The present study aimed to investigate the potential role of P2X7R in Chinese patients with AMI. METHODS: Seventy-nine patients with AMI and 48 controls were consecutively enrolled in this prospective observational study. Circulating P2X7R mRNA expression levels and other clinical variables were determined upon admission to the hospital. Patients were followed up for 360 days, and the end-point was considered as the occurrence of major adverse cardiovascular events (MACE). RESULTS: Circulating P2X7R mRNA expression level in peripheral blood mononuclear cells of patients with AMI were significantly higher than those in controls and had promising diagnostic ability of AMI with an area under the curve of 0.928. Furthermore, P2X7R was demonstrated to be correlated positively with the severity of coronary artery stenosis. Additionally, this is the first study to indicate that higher P2X7R mRNA expression is associated with a higher rate of MACE within 360 days after AMI. CONCLUSIONS: The present study showed that the circulating level of P2X7R was elevated in AMI patients and was closely associated with the severity of coronary artery stenosis and prognosis of AMI.

Age shock index and age-modified shock index are strong predictors of outcomes in ST-segment elevation myocardial infarction patients undergoing emergency percutaneous coronary intervention.

BACKGROUND: Early identification of high-risk patients provides clinicians with greater decision-making time and better informs strategies to cope with disease. The predictive values of age shock index (age SI) and age-modified shock index (age MSI) in ST-segment elevation myocardial infarction (STEMI) patients undergoing emergency percutaneous coronary intervention (PCI) have rarely been reported, especially compared with those for SI, MSI, and the Global Registry of Acute Coronary Events (GRACE) risk score. PATIENTS AND METHODS: Nine hundred and eighty-three STEMI patients undergoing emergency PCI between January 2014 and September 2017 were analyzed in a retrospective cohort study. The primary outcomes were rates of in-hospital cardiovascular events, and 6-month and long-term all-cause mortality. RESULTS: In multivariate analyses, the predictive values of age SI and age MSI were comparable to that of the GRACE score, but superior to those of SI and MSI for in-hospital cardiac mortality [age SI: odds ratio (OR) = 1.05, P < 0.001, area under the receiver operating characteristic (ROC-AUC) = 0.805, P < 0.001; age MSI: OR = 1.04, P < 0.001, ROC-AUC = 0.813, P < 0.001; GRACE score: OR = 1.03, P < 0.001, ROC-AUC = 0.827, P < 0.001], 6-month all-cause mortality (age SI: OR = 1.04, P < 0.001, ROC-AUC = 0.791, P < 0.001; age MSI: OR = 1.03, P < 0.001, ROC-AUC = 0.801, P < 0.001; GRACE score: ROC-AUC = 0.828, P < 0.001), long-term all-cause mortality [age SI: hazard ratio (HR) = 1.06, P < 0.001, ROC-AUC = 0.798, P < 0.001; age MSI: HR = 1.04, P < 0.001, ROC-AUC = 0.84, P < 0.001; GRACE score: ROC-AUC = 0.822, P < 0.001] and post-discharge all-cause mortality (age SI: HR = 1.05, P < 0.001, ROC-AUC = 0.78, P = 0.001; age MSI: HR = 1.05, P < 0.001, ROC-AUC = 0.789, P < 0.001; GRACE score: ROC-AUC = 0.812, P < 0.001). CONCLUSION: Age SI and age MSI are stronger predictors than SI and MSI for in-hospital cardiovascular events, and 6-month and long-term all-cause mortality in STEMI patients undergoing emergency PCI. Age SI and age MSI appear to be convenient and simpler indicators than the GRACE score.

Influence of Body Mass Index on the Activated Clotting Time Under Weight-Based Heparin Dose.

BACKGROUND: Activated clotting time (ACT) has been successfully applied during percutaneous coronary intervention (PCI) to monitor the extent of thrombin inhibition and anti-coagulation from unfractionated heparin (UFH) aiming to reduce the incidence of thrombotic adverse events and hemorrhagic complications. And this investigation was to explore the influence of body mass index (BMI) on ACT in patients received weight-based dose of UFH during PCI treatment. METHODS: 78 male patients undergoing coronary angiography or PCI treatment with a mean age of 63.86 ± 6.89 years were enrolled in this study. The patients were statistically divided into four quartiles according to their BMI. The ACT values were recorded as ACT0 , ACT5 , ACT10 , ACT30 and ACT60 , respectively. Taking the preoperative ACT0 as reference, and the differences of the other ACT values with ACT0 was indicated as ΔACTs. ACT values peaked at 5 min in 33.33% of the patients, 10 min in 51.33% of the patients and 30 min in 15.34% of the patients, respectively. RESULTS: In addition, significant differences were found in overall maximum post-UFH ACT values among all BMI quartiles. UFH doses per blood volume were significantly different among the BMI quartiles, showing a positive association with BMI quartiles; further evidence revealed that the areas under the ΔACT-time curves increased gradually from quartile I to quartile IV. The proportions of ACT60 > 250 s and ACT60 > 300 s were found to be positively correlated with the increased BMI at 60 min after heparin loading. CONCLUSIONS: The results of our study have shown that a standardized dosing nomogram that uses the actual body weight to calculate the heparin doses may result in UFH overdose for patients with higher BMI compared to patients with lower BMI.

Overexpression of microRNA-133a inhibits ischemia-reperfusion-induced cardiomyocyte apoptosis by targeting DAPK2.

To examine microRNA-133a (miR-133a) endogenous expression in cardiomyocytes after ischemia-reperfusion (I/R) injury and study the effects of miR-133a overexpression on I/R injury-induced cardiomyocyte apoptosis. Dual-Luciferase Reporter Assay detected dynamic expression of miR-133a. In an in vitro hypoxia-reoxygenation (HR) injury model and an in vivo rat model of I/R injury, rat cardiomyocytes were transfected with miR-133a mimic to test the effects of miR-133a overexpression on apoptosis. MiR-133a and Death Associated Protein Kinase 2 (DAPK2) mRNA expression was measured using real-time-PCR, and DAPK2 protein expression was detected by western blotting. Annexin V-fluorescein isothiocyanate/propidium iodide (PI) double-staining measured the apoptosis rate in H9C2 cells and transferase dUTP nick end labeling assay quantified the cardiomyocyte apoptosis rate in tissues obtained from in vivo the rat model. DAPK2 is a target of miR-133a. Both in vitro and in vivo results confirmed that after expression of miR-133a mimics, miR-133a levels increased, which was accompanied by decrease in DAPK2 mRNA and protein expression. In H9C2 cells, HR injury caused a sharp decrease in miR-133a expression and a significant upregualtion of DAPK2 mRNA and protein levels. However, exogenous miR-133a expression led to a significant reduction in DAPK2 mRNA and protein levels despite HR injury. Similar results were obtained from in vivo I/R injury model. After HR injury or I/R injury the apoptosis rate of myocardial cells was highly elevated and decreased significantly only after transfection of miR-133a into cardiomyocytes. MiR-133a overexpression may inhibit I/R injury-mediated cardiomyocyte apoptosis by targeting DAPK2, leading to reduced DAPK2 protein, thus miR-133a may potentially have a high therapeutic value in I/R injury.

Protective role of retinoid X receptor in H9c2 cardiomyocytes from hypoxia/reoxygenation injury in rats.

BACKGROUND: Retinoid X receptor (RXR) plays a central role in the regulation of intracellular receptor signaling pathways. The activation of RXR has protective effect on H2O2-induced apoptosis of H9c2 ventricular cells in rats. But the protective effect and mechanism of activating RXR in cardiomyocytes against hypoxia/reoxygenation (H/R)-induced oxidative iniury are still unclear. METHODS: The model of H/R injury was established through hypoxia for 2 hours and reoxygenation for 4 hours in H9c2 cardiomyocytes of rats. 9-cis-retinoic acid (9-cis RA) was obtained as an RXR agonist, and HX531 as an RXR antagonist. Cultured cardiomyocytes were randomly divided into four groups: sham group, H/R group, H/R+9-cis RA -pretreated group (100 nmol/L 9-cis RA), and H/R+9-cis RA+HX531-pretreated group (2.5 µmol/L HX531). The cell viability was measured by MTT, apoptosis rate of cardiomyocytes by flow cytometry analysis, and mitochondrial membrane potential (ΔΨm) by JC-1 fluorescent probe, and protein expressions of Bcl-2, Bax and cleaved caspase-9 with Western blotting. All measurement data were expressed as mean±standard deviation, and analyzed using one-way ANOVA and the Dunnett test. Differences were considered significant when P was <0.05. RESULTS: Pretreatment with RXR agonist enhanced cell viability, reduced apoptosis ratio, and stabled ΔΨm. Dot blotting experiments showed that under H/R stress conditions, Bcl-2 protein level decreased, while Bax and cleaved caspase-9 were increased. 9-cis RA administration before H/R stress prevented these effects, but the protective effects of activating RXR on cardiomyocytes against H/R induced oxidative injury were abolished when pretreated with RXR pan-antagonist HX531. CONCLUSION: The activation of RXR has protective effects against H/R injury in H9c2 cardiomyocytes of rats through attenuating signaling pathway of mitochondria apoptosis.

[Farnesoid-X-receptor blockade reduces myocardial reperfusion injury in cholesterol-fed apolipoprotein E knockout mice].

OBJECTIVE: To investigate the effect of farnesoid-X-receptor (FXR) antagonist Z-guggulsterone in an in vivo high-fat fed apolipoprotein E knockout (ApoE(-/-)) mice model of myocardial ischemia/reperfusion (I/R). METHODS: Male ApoE(-/-) mice were randomly divided into three groups: standard ApoE(-/-) group (fed with standard mouse diet for 12 weeks before myocardial I/R procedure, n = 18), high-fat ApoE(-/-) group (fed with high-fat mouse diet for 12 weeks before myocardial I/R procedure, n = 22), and high-fat ApoE(-/-) + FXR antagonist group(fed with high-fat mouse diet for 12 weeks and received FXR antagonist Z-Guggulsterone 30 minutes before myocardial I/R procedure, n = 17). The expression of FXR was detected by real-time quantitative-PCR. Myocardial infarct size was determined by Evans blue/TTC double staining methods. Myocardial apoptosis was determined by in situ TUNEL technique. Markers of the mitochondrial-mediated apoptotic pathway (cytochrome c release, caspase-9 activity, and BAX and BCL-2 levels), endoplasmic reticulum stress apoptotic pathway (caspase-12 activity and CHOP level), and death receptor apoptotic pathway (caspase-8 activity, and Fas and FasL levels) were also measured. RESULT: FXR expression (3.7-fold higher, P < 0.01), myocardial infarct size [(62.1 ± 7.0)% vs. (33.8 ± 5.8)%, P < 0.01] and myocardial apoptosis index[ (36.8 ± 5.7)% vs. (17.2 ± 3.8)%, P < 0.01]were all significantly higher in high-fat ApoE(-/-) group than those in standard ApoE(-/-) group. Compared with high-fat ApoE(-/-) group, myocardial infarct size [(24.4 ± 4.7)% vs. (62.1 ± 7.0)%, P < 0.01] and myocardial apoptosis index [(13.8 ± 2.7)% vs. (36.8 ± 5.7)%, P < 0.01] were significantly reduced in high-fat ApoE(-/-) + FXR antagonist group. Moreover, levels of mitochondrial-mediated apoptotic pathway markers (cytochrome c release, caspase-9 activity, and BAX/BCL-2 levels) and endoplasmic reticulum stress apoptotic pathway markers (caspase-12 activity and CHOP level) were significantly lower in high-fat ApoE(-/-) + FXR antagonist group than those in high-fat ApoE(-/-) group (all P < 0.01). Levels of death receptor apoptotic pathway markers (caspase-8 activity, and Fas and FasL levels) were similar between high-fat ApoE(-/-) group and high-fat ApoE(-/-) + FXR antagonist group. CONCLUSION: FXR antagonist alleviates myocardial reperfusion injury in cholesterol-fed ApoE(-/-) mice via inhibition of the mitochondrial-mediated and endoplasmic-reticulum stress pathway.

[Relationship between antithrombin-III value with acute coronary syndrome and preprocedural TIMI flow grade].

OBJECTIVE: To explore the differences of antiprothrombin-III (AT-III) value in patients with acute coronary syndrome (ACS) and stable angina pectoris (SAP) and examine the association of AT-III value with preprocedural thrombolysis in myocardial infarction (TIMI) flow in ACS patients. METHODS: This study prospectively included 121 hospitalized ACS patients between February 2011 to June 2011, including ST-segment elevation myocardial infarction (STEMI, n = 50), non-ST segment elevation myocardial infarction (NSTEMI, n = 32) and unstable angina (UAP, n = 39). Meanwhile, 50 SAP cases during the same period were selected as the control group. The AT-III levels were measured by chromogenic substrate method before coronary angiography for all patients. RESULTS: (1) The AT-III levels were significantly lower in the ACS patients than those in the SAP cases. (2) In the STEMI subgroup, the AT-III levels were markedly lower in the patients with preprocedural TIMI flow grade ≤ 2 versus those with preprocedural TIMI flow grade 3 (86% ± 11% vs 93% ± 9%, P < 0.05). (3) In the USTEMI/UAP subgroup, the mean levels of AT-III were obviously lower in the patients with preprocedural TIMI flow grade ≤ 2 than those with preprocedural TIMI flow grade 3 (85% ± 8% vs 95% ± 8%, P < 0.01) and were notably lower in the patients with the culprit lesion stenosis ≥ 70% versus those with stenosis < 70% (88% ± 9% vs 94% ± 9%, P < 0.01). (4) Multivariable analysis identified AT-III value as an independent predictor of impaired preprocedural TIMI flow grade of culprit coronary artery in ACS patients. CONCLUSION: The AT-III levels were significantly lower in the ACS patients than those in the SAP patients. The activity of AT-III is positively correlated with the TIMI flow grade in ACS patients. In contrast, the activity of AT-III is negatively correlated with the severity of culprit vessel stenosis in the patients with NSTEMI. Thus AT-III level may be used to distinguish high-risk populations in ACS patients at an early stage.

Factors affecting thrombolysis in myocardial infarction myocardial perfusion frame count: insights of myocardial tissue-level reperfusion from a novel index for assessing myocardial perfusion.

BACKGROUND: Myocardial tissue-level perfusion failure is associated with adverse outcomes following ST-elevation myocardial infarction (STEMI) despite successful epicardial recanalization. We have developed a new quantitative index-thrombolysis in myocardial infarction (TIMI) myocardial perfusion frame count (TMPFC)--for assessing myocardial tissue level perfusion. However, factors affecting this novel index of myocardial perfusion are currently unknown. METHODS: A total of 255 consecutive STEMI patients undergoing primary angioplasty were enrolled. Myocardial tissue level perfusion was assessed by TMPFC, which measures the filling and clearance of contrast in the myocardium using cine-angiographic frame counting. We differentiate three groups with two cut off values for TMPFC: a TMPFC of 90 frames was the upper boundary of the 95% confidence interval (CI) for the TMPFC observed in normal arteries, and a TMPFC of 130 was the 75th percentile of TMPFC. RESULTS: STEMI patients with TMPFC > 130 frames (68 patients, 26.7%) had higher clinical and angiographic risk factor profiles as well as a higher 30-day MACE rate compared with those with TMPFC ≤ 90 frames and those with TMPFC > 90 and ≤ 130 frames. Multivariable analysis identified that the independent predictors of TMPFC > 130 frames were age ≥ 75 years (OR 2.08, 95%CI 1.21 to 3.58, P = 0.007), diabetes (OR 1.37, 95%CI 1.01 to 1.86, P = 0.042), Killip class ≥ 2 (OR 1.52, 95%CI 1.05 to 2.21, P = 0.027), and prolonged pain-to-balloon time (OR 1.73, 95%CI 1.07 to 2.79, P = 0.013). TMPFC > 130 frames was identified as the strongest independent predictor of 30-day major adverse cardiac event (MACE) (OR 2.77, 95%CI 1.21 to 6.31, P = 0.008), along with age ≥ 75 years (OR 2.19, 95%CI 1.11 to 4.33, P = 0.016), female gender (OR 1.67, 95%CI 1.03 to 2.70, P = 0.038), and Killip class ≥ 2 (OR 1.83, 95%CI 1.07 to 3.14, P = 0.021). CONCLUSIONS: STEMI patients with poor myocardial perfusion assessed by TMPFC had higher risk factor profiles. Advanced age, diabetes, higher Killip class, and longer ischemia time were independent predictors of impaired TMPFC after primary percutaneous coronary intervention. These results emphasize that particular attention should be paid on myocardial microvascular reperfusion in STEMI patients with these risk factors.