Phosphorylation of CaMK and CREB-Mediated Cardiac Aldosterone Synthesis Induced by Arginine Vasopressin in Rats with Myocardial Infarction.

Both aldosterone and arginine vasopressin (AVP) are produced in the heart and may participate in cardiac fibrosis. However, their relationship remains unknown. This study aims to demonstrate the regulation and role of AVP in aldosterone synthesis in the heart. Rats were subjected to a sham operation or myocardial infarction (MI) by ligating the coronary artery. Cardiac function and fibrosis were assessed using echocardiography and immunohistochemical staining, respectively. In addition, the effects of AVP stimulation on cardiac microvascular endothelial cells (CMECs) were studied using ELISA, real-time PCR, and Western blotting. Compared with the rats having undergone a sham operation, the MI rats had an increased LVMI, type I collagen composition, and concentrations of aldosterone and AVP in the heart but decreased cardiac function. As the MI rats aged, the LVMI, type I collagen, aldosterone, and AVP increased, while the LVMI decreased. Furthermore, AVP time-dependently induced aldosterone secretion and CYP11B2 mRNA expression in CMECs. The p-CREB levels were significantly increased by AVP. Nevertheless, these effects were completely blocked by SR49059 or partially inhibited by KN93. This study demonstrated that AVP could induce the secretion of local cardiac aldosterone, which may involve CaMK and CREB phosphorylation and CYP11B2 upregulation through V1 receptor activation.

Inhibition of perivascular mast cell activation is involved in the atheroprotective effect of rosiglitazone in apolipoprotein E-deficient mice.

Activation of perivascular mast cells (MCs) and subsequent release of their abundant inflammatory mediators have been well documented to induce excessive inflammation and subsequent rupture of atherosclerotic plaques. Previous studies have suggested that rosiglitazone affects the stability of plaques, although the precise mechanism of action is not clearly understood. In this study, we evaluated the effects of rosiglitazone on MCs in vivo and in vitro. Apolipoprotein E-deficient (ApoE-/-) mice were fed a high-fat diet (HFD), with or without rosiglitazone supplemented in the drinking water (1.5 mg/kg/day). Compared with the HFD group, rosiglitazone did not affect blood glucose levels, but it attenuated serum levels of tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6), ameliorated plaque lipid accumulation and the expression of matrix metalloproteinases-2 and -9, increased the collagen content of plaques, and inhibited perivascular MC degranulation and chymase expression. The in vitro experiments showed that rosiglitazone treatment repressed the expression of TNFα and IL-6 induced by antigen-challenged RBL-2H3 cells in a peroxisome proliferator-activated receptor γ (PPARγ)-independent manner, which was related to the repression of protein kinase C (PKC)-ß1 activation. Combined, these results suggest that the plaque-stabilizing effect of rosiglitazone is attributable to its ability to inhibit the activation of perivascular MCs.

Spironolactone suppresses aldosterone-induced Kv1.5 expression by attenuating mineralocorticoid receptor-Nox1/2/4-mediated ROS generation in neonatal rat atrial myocytes.

Our previous investigation indicated that angiotensin II (Ang II) enhances the expression of Kv1.5, a promising target for the treatment of atrial fibrillation (AF), by activating reactive oxygen species (ROS)-dependent phosphorylation of Smad 2/3 (forming P-Smad 2/3) and ERK 1/2 (forming P-ERK 1/2). A recent study indicated that aldosterone (Aldo) upregulates atrial Kv1.5 protein in a rat AF model, but the mechanism remains unknown. The present study aimed to clarify the mechanism underlying Aldo-induced Kv1.5 expression and to test whether spironolactone may modulate atrial Kv1.5. Our Western blot analysis indicated that the Aldo/mineralocorticoid receptor (MR) interacts with Ang II/AT1R in upregulating Kv1.5 expression in cultured neonatal atrial myocytes (NRAMs). Blockade of MR with spironolactone and of AT1R with losartan significantly suppressed Kv1.5 expression induction by combined Aldo and Ang II treatment. Aldo increased the protein expression of Nox1, Nox2 and Nox4, but this effect was abolished by spironolactone pretreatment. The Aldo-induced upregulation of Kv1.5 was also reversed by the Src protein tyrosine kinase family inhibitor PP2, the Nox2 inhibitor gp91ds-tat and the Nox1/Nox4 inhibitor GKT137831 but not by the Rac GTPase inhibitor NSC23766. Flow cytometry showed that the Aldo-induced ROS production was inhibited by spironolactone, PP2, gp91ds-tat and GKT137831. Spironolactone suppressed the Aldo-induced protein expression phosphorylated Src (P-Src), P-Smad 2/3 and P-ERK 1/2. In conclusion, we have demonstrated that spironolactone suppresses Aldo-induced Kv1.5 expression by attenuating MR-Nox1/2/4-mediated ROS generation in NRAMs.

Incidence of chemotherapy-related cardiac dysfunction in cancer patients.

BACKGROUND: Cancer patients are increasingly affected by chemotherapy-related cardiac dysfunction. The reported incidence of this condition vary significantly across different studies. HYPOTHESIS: A better comprehensive understanding of chemotherapy-related cardiac dysfunction incidence in cancer patients is imperative. Therefore, we performed a meta-analysis to establish the overall incidence of chemotherapy-related cardiac dysfunction in cancer patients. METHODS: We searched articles in PubMed and EMBASE from database inception to May 1, 2023. Studies that reported the incidence of chemotherapy-related cardiac dysfunction in cancer patients were included. RESULTS: A total of 53 studies involving 35 651 individuals were finally included in the meta-analysis. The overall pooled incidence of chemotherapy-related cardiac dysfunction in cancer patients was 63.21 per 1000 person-years (95% CI: 57.28-69.14). The chemotherapy-related cardiac dysfunction incidence increased steeply within half a year of cancer chemotherapy. Also, the trend of chemotherapy-related cardiac dysfunction incidence appeared to have plateaued after a longer duration of follow-up. In addition, chemotherapy-related cardiac dysfunction incidence rates are significantly higher among patients with age ≥50 years versus patients with age <50 years (99.96 vs. 34.48 per 1000 person-years). The incidence rate of cardiac dysfunction was higher among breast cancer patients (72.97 per 1000 person-years), leukemia patients (65.21 per 1000 person-years), and lymphoma patients (55.43 per 1000 person-years). CONCLUSION: Our meta-analysis unveiled a definitive overall incidence rate of chemotherapy-related cardiac dysfunction in cancer patients. In addition, it was found that the risk of developing this condition escalates within the initial 6 months postchemotherapy, subsequently tapering off to become statistically insignificant after a duration of 6 years.

Plasma Fibronectin as a Novel Predictor of Coronary Heart Disease: A Retrospective Study.

Although fibronectin has been associated with the pathogenesis of atherosclerosis, little is currently known about the relationship between plasma fibronectin and coronary heart disease (CHD). This retrospective study aimed to determine the predictive value of plasma fibronectin for CHD and its severity. A total of 1644 consecutive patients who underwent selective coronary angiography were recruited into the present study. The characteristics and results of the clinical examination of all patients were collected. Logistic regression analyses were performed to determine the predictive value of plasma fibronectin for the presence and severity of CHD. Compared with non-CHD patients, the CHD patients showed significantly higher plasma levels of troponin I and creatine kinase isoenzyme, along with lower plasma levels of fibronectin. However, no significant differences were detected in plasma fibronectin among patients with different grades of CHD. The logistic regression model showed that plasma fibronectin remained an independent predictor of CHD after adjustment with a 1.39-fold increased risk for every 1 SD decrease in plasma fibronectin. Nevertheless, plasma fibronectin could not predict the severity of CHD determined by the number of stenosed vessels and the modified Gensini score. This study demonstrated that lower plasma fibronectin might be an independent predictor of CHD, but it may be of no value in predicting the severity of CHD.

Associations of Renal Function Trajectories and Long-Term Cardiovascular Risks Among a Population Without Chronic Kidney Disease.

Background The longitudinal trajectories of renal function have been associated with cardiovascular events in patients with chronic kidney disease (CKD). However, the change pattern of renal function in those without CKD has not yet been reported. We aim to explore patterns of renal function change in a non-CKD population and its associated risks with cardiovascular outcomes. Methods and Results The present study analyzed data from 4 prospective cohorts and was restricted to participants without baseline CKD. The primary outcome was major adverse cardiovascular events, defined as a composite of myocardial infarction, chronic heart failure, stroke, and cardiovascular deaths. We used a group-based trajectory model to identify latent groups and analyzed the associated risk with Cox regression models. The complete dates of this study were June 1, 2020, through January 1, 2021. The final sample comprised 23 760 participants (mean age, 58.63 [9.12] years, 10 618 men, and 17 799 White participants). During 20.56 years follow-up, 8328 (35.05%) first major adverse cardiovascular events happened. Four trajectories in estimated glomerular renal function and 3 patterns of CKD progression were identified. Compared with subjects assigned to class I trajectory (high to mildly decreased group), the adjusted hazard ratios of major adverse cardiovascular events for class II (normal to mildly decreased group), class III (normal to moderately decreased group), and class IV (mildly to severely decreased group) were 1.11 (95% CI, 1.01-1.23), 1.27 (95% CI, 1.14-1.40), and 1.56 (95% CI, 1.38-1.77), respectively. Likewise, participants assigned to the slow and rapid progression groups had elevated HRs for major adverse cardiovascular events (1.75 [95% CI, 1.39-2.21] and 2.19 [95% CI, 1.68-2.86], respectively) when compared with the stable group. Findings were generally consistent in stratification analysis, but significant interaction effects by age and smoking status were detected. Conclusions In this study, we identified unique trajectory groups for renal function. These findings may signal an underlying high-risk population and inspire future studies on individualized risk management.

The role of glucocorticoids in increasing cardiovascular risk.

Introduction: Different studies provide conflicting evidence regarding the potential for glucocorticoids (GCs) to increase the risk of cardiovascular diseases. This study performed a systematic review and meta-analysis to determine the correlation between GCs and cardiovascular risk, including major adverse cardiovascular events (MACE), death from any cause, coronary heart disease (CHD), heart failure (HF), and stroke. Methods: We performed a comprehensive search in PubMed and Embase (from inception to June 1, 2022). Studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Results: A total of 43 studies with 15,572,512 subjects were included. Patients taking GCs had a higher risk of MACE (RR = 1.27, 95% CI: 1.15-1.40), CHD (RR = 1.25, 95% CI: 1.11-1.41), and HF (RR = 1.92, 95% CI: 1.51-2.45). The MACE risk increased by 10% (95% CI: 6%-15%) for each additional gram of GCs cumulative dose or by 63% (95% CI: 46%-83%) for an additional 10 µg daily dose. The subgroup analysis suggested that not inhaled GCs and current GCs use were associated with increasing MACE risk. Similarly, GCs were linked to an increase in absolute MACE risk of 13.94 (95% CI: 10.29-17.58) cases per 1,000 person-years. Conclusions: Administration of GCs is possibly related with increased risk for MACE, CHD, and HF but not increased all-cause death or stroke. Furthermore, it seems that the risk of MACE increased with increasing cumulative or daily dose of GCs.

Dynamic Change of Cardiovascular Health Metrics and Long-Term Risk of Sudden Cardiac Death: The ARIC Study.

Background The change of cardiovascular health (CVH) status has been associated with risk of cardiovascular disease. However, no studies have explored the change patterns of CVH in relation to risk of sudden cardiac death (SCD). We aim to examine the link between baseline CVH and change of CVH over time with the risk of SCD. Methods and Results Analyses were conducted in the prospective cohort ARIC (Atherosclerosis Risk in Communities) study, started in 1987 to 1989. ARIC enrolled 15 792 individuals 45 to 64 years of age from 4 US communities (Forsyth County, North Carolina; Jackson, Mississippi; suburbs of Minneapolis, Minnesota; and Washington County, Maryland). Subjects with 0 to 2, 3 to 4, and 5 to 7 ideal metrics of CVH were categorized as having poor, intermediate, or ideal CVH, respectively. Change in CVH over 6 years between 1987 to 1989 and 1993 to 1995 was considered. The primary study outcome was physician adjudicated SCD. The study population consisted of 15 026 subjects, of whom 12 207 had data about CVH change. Over a median follow-up of 23.0 years, 583 cases of SCD were recorded. There was a strong inverse association between baseline CVH metrics and time varying CVH metrics with risk of SCD. Compared with subjects with consistently poor CVH, risk of SCD was lower in those changed from poor to intermediate/ideal (hazard ratio [HR], 0.67 [95% CI, 0.48-0.94]), intermediate to poor (HR, 0.73 [95% CI, 0.54-0.99]), intermediate to ideal (HR, 0.49 [95% CI, 0.24-0.99]), ideal to poor/intermediate CVH (HR, 0.23 [95% CI, 0.10-0.52]), or those with consistently intermediate (HR, 0.49 [95% CI, 0.36-0.66]) or consistently ideal CVH (HR, 0.31 [95% CI, 0.13-0.76]). Similar results were also observed for non-SCD. Conclusions Compared with consistently poor CVH, other patterns of change in CVH were associated with lower risk of SCD. These findings highlight the importance of promotion of ideal CVH in the primordial prevention of SCD.

Association Between Silent Myocardial Infarction and Long-Term Risk of Sudden Cardiac Death.

Background Although silent myocardial infarction (SMI) is prognostically important, the risk of sudden cardiac death (SCD) among patients with incident SMI is not well established. Methods and Results We examined 2 community-based cohorts: the ARIC (Atherosclerosis Risk in Communities) study (n=13 725) and the CHS (Cardiovascular Health Study) (n=5207). Incident SMI was defined as electrocardiographic evidence of new myocardial infarction during follow-up visits that was not present at the baseline. The primary study end point was physician-adjudicated SCD. In the ARIC study, 513 SMIs, 441 clinically recognized myocardial infarctions (CMIs), and 527 SCD events occurred during a median follow-up of 25.4 years. The multivariable hazard ratios of SMI and CMI for SCD were 5.20 (95% CI, 3.81-7.10) and 3.80 (95% CI, 2.76-5.23), respectively. In the CHS, 1070 SMIs, 632 CMIs, and 526 SCD events occurred during a median follow-up of 12.1 years. The multivariable hazard ratios of SMI and CMI for SCD were 1.70 (95% CI, 1.32-2.19) and 4.08 (95% CI, 3.29-5.06), respectively. The pooled hazard ratios of SMI and CMI for SCD were 2.65 (2.18-3.23) and 3.99 (3.34-4.77), respectively. The risk of SCD associated with SMI is stronger with White individuals, men, and younger age. The population-attributable fraction of SCD was 11.1% for SMI, and SMI was associated with an absolute risk increase of 8.9 SCDs per 1000 person-years. Addition of SMI significantly improved the predictive power for both SCD and non-SCD. Conclusions Incident SMI is independently associated with an increased risk of SCD in the general population. Additional research should address screening for SMI and the role of standard post-myocardial infarction therapy.

CD51 distinguishes a subpopulation of bone marrow mesenchymal stem cells with distinct migratory potential: a novel cell-based strategy to treat acute myocardial infarction in mice.

BACKGROUND: Experimental and clinical trials have demonstrated the efficiency of bone marrow-derived mesenchymal stromal/stem cells (bMSCs) in the treatment of myocardial infarction. However, after intravenous injection, the ineffective migration of engrafted bMSCs to the hearts remains an obstacle, which has an undesirable impact on the efficiency of cell-based therapy. Therefore, we attempted to identify a marker that could distinguish a subpopulation of bMSCs with a promising migratory capacity. METHODS: Here, CD51-negative and CD51-positive cells were isolated by flow cytometry from Ter119-CD45-CD31-bMSCs and cultured in specifically modified medium. The proliferation ability of the cells was evaluated by 5-ethynyl-2'-deoxyuridine (EdU) staining or continuously monitored during culture, and the differentiation potential was assessed by culturing the cells in the appropriate conditioned media. Wound healing assays, transwell assays and quantitative polymerase chain reaction (qPCR) were used to measure the migratory ability. The mice were subjected to a sham operation or myocardial infarction (MI) by permanently occluding the coronary artery, and green fluorescent protein (GFP)-labelled cells were transplanted into the mice via intravenous infusion immediately after MI. Heart function was measured by echocardiography; infarct myocardium tissues were detected by triphenyl tetrazolium chloride (TTC) staining. Additionally, immunofluorescence staining was used to verify the characteristics of CD51+bMSCs and inflammatory responses in vivo. Statistical comparisons were performed using a two-tailed Student's t test. RESULTS: In this study, the isolated CD51-bMSCs and CD51+bMSCs, especially the CD51+ cells, presented a favourable proliferative capacity and could differentiate into adipocytes, osteocytes and chondrocytes in vitro. After the cells were transplanted into the MI mice by intravenous injection, the therapeutic efficiency of CD51+bMSCs in improving left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) was better than that of CD51-bMSCs. Compared with CD51-bMSCs, CD51+bMSCs preferentially migrated to and were retained in the infarcted hearts at 48 h and 8 days after intravenous injection. Accordingly, the migratory capacity of CD51+bMSCs exceeded that of CD51-bMSCs in vitro, and the former cells expressed higher levels of chemokine receptors or ligands. Interestingly, the retained CD51+bMSCs retained in the myocardium possessed proliferative potential but only differentiated into endothelial cells, smooth muscle cells, fibroblasts or cardiomyocytes. Transplantation of CD51+bMSCs partially attenuated the inflammatory response in the hearts after MI, while the potential for inflammatory suppression was low in CD51-bMSC-treated mice. CONCLUSIONS: These findings indicated that the CD51-distinguished subpopulation of bMSCs facilitated proliferation and migration both in vitro and in vivo, which provided a novel cell-based strategy to treat acute MI in mice by intravenous injection.

Fluvastatin decreases cardiac fibrosis possibly through regulation of TGF-beta(1)/Smad 7 expression in the spontaneously hypertensive rats.

Statins ameliorate myocardial fibrosis after myocardial infarction. We designed this study to determine whether fluvastatin reduced hypertension-induced myocardial hypertrophy and fibrosis and whether these fluvastatin effects involved transforming growth factor beta1 (TGF-beta1) and Smad 7, factors known to play a role in the myocardial hypertrophy and fibrosis. We randomized 14 week old spontaneously hypertensive rats (SHRs) to receiving vehicle or 5-20 mg/kg/day fluvastatin for 8 weeks. Wistar Kyoto (WKY) rats receiving vehicle or 10 mg/kg/day fluvastatin were also studied. SHRs had an increased blood pressure, left ventricular hypertrophy and fibrosis compared with WKY rats. SHRs also had an elevated TGF-beta1 expression and a decreased Smad 7 expression. These changes in SHRs were dose-dependently attenuated by fluvastatin. For example, the hydroxyproline content was 3.2+/-0.1, 4.0+/-0.1 and 3.5+/-0.1 microg/mg heart and the Smad 7 protein expression was 5.1+/-0.6, 1.0+/-0.1 and 4.1+/-0.7 arbitrary units for WKY rats, SHRs and SHRs receiving 20 mg/kg/day fluvastatin, respectively. The hydroxyproline content in the SHRs treated with or without fluvastatin was positively correlated with the left ventricular mass index, systolic blood pressure and the amount of TGF-beta1 proteins and negatively correlated with the Smad 7 expression level. The left ventricular mass index was positively correlated with the systolic blood pressure. Fluvastatin did not alter the blood pressure, left ventricular mass index and collagen content of WKY rats. These results suggest that fluvastatin reduces hypertension-induced myocardial hypertrophy and fibrosis. These effects may involve an increased expression of Smad 7 and a decreased expression of TFG-beta1. Our results call for clinical studies to evaluate these fluvastatin effects in hypertensive patients.

Exogenous hydrogen sulfide promotes hepatocellular carcinoma cell growth by activating the STAT3-COX-2 signaling pathway.

The effects of hydrogen sulfide (H2S) on cancer are controversial. Our group previously demonstrated that exogenous H2S promotes the development of cancer via amplifying the activation of the nuclear factor-κB signaling pathway in hepatocellular carcinoma (HCC) cells (PLC/PRF/5). The present study aimed to further investigate the hypothesis that exogenous H2S promotes PLC/PRF/5 cell proliferation and migration, and inhibits apoptosis by activating the signal transducer and activator of transcription 3 (STAT3)-cyclooxygenase-2 (COX-2) signaling pathway. PLC/PRF/5 cells were treated with 500 µmol/l NaHS (a donor of H2S) for 24 h. The expression levels of phosphorylated (p)-STAT3, STAT3, cleaved caspase-3 and COX-2 were measured by western blot assay. Cell viability was detected by Cell Counting kit-8 assay. Apoptotic cells were observed by Hoechst 33258 staining. The expression of STAT3 and COX-2 messenger RNA (mRNA) was detected by semiquantitative reverse transcription-polymerase chain reaction. The production of vascular endothelial growth factor (VEGF) was evaluated by ELISA. The results indicated that treatment of PLC/PRF/5 cells with 500 µmol/l NaHS for 24 h markedly increased the expression levels of p-STAT3 and STAT3 mRNA, leading to COX-2 and COX-2 mRNA overexpression, VEGF induction, decreased cleaved caspase-3 production, increased cell viability and migration, and decreased number of apoptotic cells. However, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 (an inhibitor of STAT3) or 20 µmol/l NS-398 (an inhibitor of COX-2) for 24 h significantly reverted the effects induced by NaHS. Furthermore, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 markedly decreased the NaHS-induced increase in the expression level of COX-2. By contrast, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 20 µmol/l NS-398 inhibited the NaHS-induced increase in the expression level of p-STAT3. In conclusion, the findings of the present study provide evidence that the STAT3-COX-2 signaling pathway is involved in NaHS-induced cell proliferation, migration, angiogenesis and anti-apoptosis in PLC/PRF/5 cells, and suggest that the positive feedback between STAT3 and COX-2 may serve a crucial role in hepatocellular carcinoma carcinogenesis.

Angiotensin-(1-7) protects cardiomyocytes against high glucose-induced injuries through inhibiting reactive oxygen species-activated leptin-p38 mitogen-activated protein kinase/extracellular signal-regulated protein kinase 1/2 pathways, but not the leptin-c-Jun N-terminal kinase pathway in vitro.

AIMS/INTRODUCTION: Angiotensin-(1-7) (Ang-[1-7]), recognized as a new bioactive peptide in the renin-angiotensin system, shows biological and pharmacological properties in diabetic cardiovascular diseases. The leptin-induced p38 mitogen-activated protein kinase (MAPK) pathway has been reported to contribute to high glucose (HG)-induced injury. In the present study, we showed the mechanism of how Ang-(1-7) can protect against HG-stimulated injuries in H9c2 cells. MATERIALS AND METHODS: H9c2 cells were treated with 35 mmol/L glucose (HG) for 24 h to establish a model of HG-induced damage. Apoptotic cells were observed by Hoechst 33258 staining. Cell viability was analyzed by cell counter kit-8. The expression of protein was detected by western blot. Reactive oxygen species was tested by 2',7'-dichlorodihydrofluorescein diacetate staining. Mitochondrial membrane potential was measured by 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide staining. RESULTS: The present results showed that treating H9c2 cells with HG obviously enhanced the expressions of both the leptin and phosphorylated (p)-MAPK pathway. However, the overexpression levels of leptin and p-p38 MAPK/p-extracellular signal-regulated protein kinase 1/2 (ERK1/2), but not p-c-Jun N-terminal kinase, were significantly suppressed by treatment of the cells with Ang-(1-7). Additionally, leptin antagonist also markedly suppressed the overexpressions of p38 and ERK1/2 induced by HG, whereas leptin antagonist had no influence on the overexpression of c-Jun N-terminal kinase. More remarkable, Ang-(1-7), leptin antagonist, SB203580 or SP600125, respectively, significantly inhibited the injuries induced by HG, such as the increased cell viability, decreased apoptotic rate, reduction of ROS production and increased mitochondrial membrane potential. Furthermore, the overexpressions of p38 MAPK, ERK1/2 and leptin were suppressed by N-actyl-L-cystine. CONCLUSIONS: The present findings show that Ang-(1-7) protects from HG-stimulated damage as an inhibitor of the reactive oxygen species-leptin-p38 MAPK/ERK1/2 pathways, but not the leptin-c-Jun N-terminal kinase pathway in vitro.

[Ischemic postconditioning attenuates ischemia/reperfusion injury in isolated hypertrophied rat heart].

OBJECTIVE: To explore the effects of ischemic postconditioning on ischemia/reperfusion injury in isolated hypertrophied rat heart and investigate the signal transduction pathway changes induced by ischemia postconditioning. METHODS: Cardiac hypertrophy was induced in rats by abdominal aortic banding, and isolated hypertrophied rat heart ischemia/reperfusion model was made by Langendorff technique to evaluate the effects of ischemia postconditioning on left ventricular systole pressure, coronary artery flow, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) release, myocardial infarction size, and the level of myocardial phospho-protein kinase B/Akt (Ser473), phospho-glycogen synthase kinase-3beta (Ser9). Following groups were studied (n = 12 each group): IR, 30 min ischemia (I)/60 min Reperfusion (R); Post: 30 min ischemia, 6 circles of 10 s I/10 s R followed by 60 min R; Post Wort: 30 min ischemia, 6 circles of 10 s I/10 s R, wortmannin (10(-7) mol/L) followed by 60 min R; Wort: 30 min ischemia, wortmannin (10(-7) mol/L) followed by 60 min R. RESULTS: Left ventricular systolic pressure and coronary artery flow were significantly increased, myocardial infarction size and the release of CPK, LDH significantly reduced in Post group compared to that in IR group. Phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) levels were also significantly higher in Post group than that in IR group. Phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin prevented the increase of phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) induced by ischemic postconditioning, but only partly abolished the cardioprotection of ischemic postconditioning. CONCLUSION: Ischemic postconditioning attenuates ischemia/reperfusion injury in isolated hypertrophied rat heart. The cardioprotective effects of ischemic postconditioning were partly mediated through PI3K/Akt/GSK-3beta signaling pathway.

Efficacy of different doses of aspirin in decreasing blood levels of inflammatory markers in patients with cardiovascular metabolic syndrome.

OBJECTIVES: Inflammation and platelet aggregation and activation are key processes in the initiation of a cardiovascular event. Patients with metabolic syndrome have a high risk of cardiovascular events. This study determined whether small and medium doses of aspirin have anti-inflammation and antiplatelet aggregation effects in patients with metabolic syndrome. METHODS: One hundred and twenty-one consecutive patients with metabolic syndrome were randomized into three groups, receiving 100 mg/day of aspirin, 300 mg/day of aspirin or a placebo, respectively, for 2 weeks. The blood levels of thromboxane B2 (TXB2), a stable product of the platelet aggregation mediator TXA2, 6-keto-prostaglandin F1-alpha (6-keto-PGF1-alpha), a stable product of the endogenous cyclooxygenase metabolite prostaglandin I2, and inflammatory mediators including high-sensitivity C-reactive protein (hs-CRP), tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), were determined by ELISA and radioimmunoassay. KEY FINDINGS: The blood levels of hs-CRP, TNF-alpha, IL-6 and TXB2 were significantly decreased after 2 weeks of treatment with 300 mg/day of aspirin. Patients who received 100 mg/day of aspirin had decreased blood levels of hs-CRP and TXB2. The blood level of IL-6 in the 300 mg/day aspirin group was significantly lower than that in the other two groups after 2 weeks of therapy. Aspirin at either dose did not affect the blood level of 6-keto-PGF1-alpha. CONCLUSIONS: Aspirin at all doses suppresses the blood levels of inflammatory markers and the platelet aggregation mediator TXA2 in Chinese patients with metabolic syndrome. Since the suppression induced by 300 mg/day of aspirin was greater than that induced by 100 mg/day of aspirin, these data suggest that 300 mg/day of aspirin may be beneficial in decreasing the risk of cardiovascular events in Chinese patients with metabolic syndrome.