MFG-E8 facilitates heart repair through M1/M2 polarization after myocardial infarction by inhibiting CaMKII.

BACKGROUND: M1/M2 macrophage polarization affects patient outcomes after myocardial infarction (MI). The relationship between milk fat globule-epidermal growth factor 8 (MFG-E8) and Ca2+/calmodulin-dependent protein kinase II (CaMKII) on macrophage polarization after MI is unknown. To investigate the functional role of MFG-E8 in modulating cardiac M1/M2 macrophage polarization after MI, especially its influence on CaMKII signaling. METHODS: Human ventricular tissue and blood were obtained from patients with MI and controls. MFG-E8-KO mice were constructed (C57BL/6). The mice were randomized to WT-sham, sham-MFG-E8-KO, WT-PBS, rmMFG-E8 (WT injected with rmMFG-E8 10 min after MI), and MFG-E8-KO. The mouse macrophage cell line RAW264.7 was obtained. CaMKII, p-CaMKII, Akt, and NF-κB p65 were determined by qRT-PCR, western blot, and immunofluorescence. RESULTS: The MFG-E8 levels were significantly enhanced after MI in the hearts and plasma of patients with MI compared with controls. The MFG-E8 levels were significantly increased in the hearts and plasma of mice after MI. MFG-E8 was derived from cardiac fibroblasts. The administration of rmMFG-E8 improved ventricular remodeling and cardiac function after MI. rmMFG-E8 did not suppress infiltrating monocyte/macrophages into the peri-infarct area. rmMFG-E8 suppressed the polarization of macrophages to the M1 phenotype and promoted the polarization of macrophages to the M2 phenotype. rmMFG-E8 suppressed CaMKII-dependent signaling in macrophages. CONCLUSIONS: MFG-E8 and CaMKII appear to collaboratively regulate myocardial remodeling and M1/M2 macrophage polarization after MI. These observations suggest new roles for MFG-E8 in inhibiting M1 but promoting M2 macrophage polarization.

Case report: A rare case of left ventricular noncompaction in two Chinese siblings with becker muscular dystrophy caused by deletion of exons 10 to 12 in the DMD gene.

Background: Becker muscular dystrophy (BMD) is an inherited X-linked recessive condition resulting from mutations of the DMD gene encoding dystrophin. Left ventricular noncompaction (LVNC) is a rare cardiomyopathy morphologically characterized by abnormal myocardial trabeculae and deep recesses in the left ventricle. LVNC in BMD patients has only rarely been reported. Case report: In the present study, we identified a deletion mutation in exons 10 to 12 (EX10_12 del) of the DMD gene (reference sequence NM_004006.2) in two Chinese siblings with BMD and LVNC by high throughput targeted next-generation sequencing (NGS) and quantitative polymerase chain reaction (qPCR). The proband was a 22-year-old man admitted with dyspnea, abdominal distention, and polyserositis. It is noteworthy that both the proband and his younger brother manifested progressive muscular atrophy and creatine kinase (CK) elevation. Light and electron microscopy examination of muscle biopsies showed the typical features of dystrophinopathies. Cardiac magnetic resonance imaging and echocardiography demonstrated that both brothers had an enlarged left ventricle, LVNC, and reduced left ventricular ejection fraction. Finally, the proband underwent heart transplantation at age 26 with an event-free follow-up over 4 years post-transplantation. Conclusion: This case further enriches our knowledge of the symptoms, genotype, cardiac performance, management, and prognosis of BMD patients complicated by LVNC. It is recommended that early comprehensive cardiac evaluation should be considered for patients with BMD to exclude LVNC, as this may have a significant impact on their prognosis.

Pathological implication of CaMKII in NF-κB pathway and SASP during cardiomyocytes senescence.

Senescence-associated secretory phenotype (SASP) could be developed during heart ageing. But the role of SASP in cardiomyocytes senescence and its molecular mechanism remains undetermined. In this study, we observed elevated Ca2+/calmodulin -dependent protein kinase II (CaMKII) activation in both physiological aged heart and premature senescent cardiomyocytes. Notably, we confirmed the gradual SASP development induced by NF-κB activation in long-term cultured cardiomyocytes. Transgenic inhibition of CaMKII in mice (AC3-I mice) alleviated the NF-κB activation, chronic sterile inflammation and ageing-associated cardiomyopathy. Correspondingly, pharmacological inhibition of CaMKII with KN93 mitigated SASP and hindered cardiomyocytes senescence. Meanwhile, increased NF-κB activation and exacerbated cardiomyocytes senescence were observed with transgenic CaMKII activation. Collectively, our results indicated that the increased CaMKII activation accompanying ageing could aggravate NF-κB activation and SASP development and facilitate cardiomyocytes senescence and heart ageing.

CaMKII inhibition protects against hyperthyroid arrhythmias and adverse myocardial remodeling.

Hyperthyroidism can potentiate arrhythmias and cardiac hypertrophy, whereas Ca2+/calmodulin-dependent kinase II (CaMKII) promotes maladaptive myocardial remodeling. However, it remains unclear whether CaMKII contributes to the progression of hyperthyroid heart disease (HHD). This study demonstrated that CaMKII inhibition can relieve adverse myocardial remodeling and reduce sinus tachycardia, isoproterenol-induced atrial fibrillation, and ventricular arrhythmias in hyperthyroid mice with preserved heart function. Hyperthyroid cardiac hypertrophy was promoted by CaMKII upregulation-induced HDAC4/MEF2a activation. Briefly, CaMKII inhibition benefits HHD management greatly in mice by preventing arrhythmias and maladaptive remodeling.

Ca2+/calmodulin-dependent protein kinase II inhibition reduces myocardial fatty acid uptake and oxidation after myocardial infarction.

An AMP-activated kinase (AMPK) signaling pathway is activated during myocardial ischemia and promotes cardiac fatty acid (FA) uptake and oxidation. Similarly, the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) is also triggered by myocardial ischemia, but its function in FA metabolism remains unclear. Here, we explored the role of CaMKII in FA metabolism during myocardial ischemia by investigating the effects of cardiac CaMKII on AMPK-acetyl-CoA carboxylase (ACC), malonyl CoA decarboxylase (MCD), and FA translocase cluster of differentiation 36 (FAT/CD36), as well as cardiac FA uptake and oxidation. Moreover, we tested whether CaMKII and AMPK are binding partners. We demonstrated that diseased hearts from patients with terminal ischemic heart disease displayed increased phosphorylation of CaMKII, AMPK, and ACC and increased expression of MCD and FAT/CD36. AC3-I mice, which have a genetic myocardial inhibition of CaMKII, had reduced gene expression of cardiac AMPK. In post-MI (myocardial infarction) AC3-I hearts, AMPK-ACC phosphorylation, MCD and FAT/CD36 levels, cardiac FA uptake, and FA oxidation were significantly decreased. Notably, we demonstrated that CaMKII interacted with AMPK α1 and α2 subunits in the heart. Additionally, AC3-I mice displayed significantly less cardiac hypertrophy and apoptosis 2 weeks post-MI. Overall, these findings reveal a unique role for CaMKII inhibition in repressing FA metabolism by interacting with AMPK signaling pathways, which may represent a novel mechanism in ischemic heart disease.

Maternal vitamin D intake during pregnancy and risk of asthma and wheeze in children: a systematic review and meta-analysis of observational studies.

Aims: To summarize the relationship between vitamin D and infant asthma or wheeze.Materials and methods: We used PubMed and Embase to search articles through July 2017 with selection criteria for relevant studies. Random-effect models were used to pool the results of included studies.Results: Ten articles with 14 independent reports of 2073 incident cases of asthma and 1875 cases of wheeze among 23 030 pairs of mother and child were included in our meta-analysis. Compared to those who did not take vitamin D, the mothers who had vitamin D supplementation during pregnancy stage could reduce the risk of asthma or wheeze in infants. The combined odds ratio of infant wheeze was 0.65 (95% CI = 0.54-0.79) and asthma was 0.78 (95% CI = 0.69-0.89). The results almost did not change in the subgroup analyses.Conclusions: It suggests that increasing maternal vitamin D intake during pregnancy might have a protective effect on suffering from wheeze and asthma for children.

Sleep duration and risk of coronary heart disease: A systematic review and meta-analysis of prospective cohort studies.

BACKGROUND: Epidemiological studies suggest an association between sleep duration and risk of coronary heart disease, however, the results are controversial. We conducted this systematic review and meta-analysis to summarize the potential dose-response relationship between sleep duration and risk of coronary heart disease. METHODS: The electronic reference databases (PubMed and Embase) were searched through January 2016 with selection criteria for relevant studies. Both semiparametric and parametric methods were used to calculate the pooled risk estimates. RESULTS: Seventeen articles with 22 independent reports involving 17,841 incident cases of coronary heart disease among 517,440 participants were included in our meta-analysis. A U-shaped relationship was detected between sleep duration and risk of coronary heart disease, with the lowest risk at 7-8h per day. Compared with 7h sleep duration per day, the combined relative risk of coronary heart disease were 1.11 (95% CI=1.05-1.16) for an reduction of 1h and 1.07 (95% CI=1.00-1.15) for an increment of 1h. And the results almost did not change in the subgroup analysis of gender and fatal cases. Exclusion of any single study did not alter the combined relative risk. In addition, visual inspection of funnel plots, Begg's and Egger's tests failed to identify publication bias. CONCLUSIONS: Both short and long sleep durations are significantly associated with increased risk of coronary heart disease. Compared with 7h sleep duration per day, the risk of coronary heart disease increases 11% for an hour decrease and increases 7% for an hour increase.

Relaxin-2 improves diastolic function of pressure-overloaded rats via phospholamban by activating Akt.

BACKGROUND: Relaxin is a peptide hormone which has been demonstrated to be safe and has a therapeutic effect on acute heart failure in clinic trials. However, its effect on diastolic function is still unknown. The aims of the study were to determine whether relaxin could improve the diastolic function in pressure-overloaded rat model and to analyze potential mechanisms. METHODS AND RESULTS: In the present study, a pressure-overloaded rat model induced by transaortic constriction (TAC) was established. Four weeks after TAC, echocardiography was performed and then all the rat models were randomly divided into 3 groups: models without intramyocardial injection (TAC), with intramyocardial injection of empty adenoviral vector (TAC+GFP) and adenoviral vector overexpression relaxin-2 gene (TAC+RLN2). A sham group was also included. Twelve days after intramyocardial injection, echocardiography and hemodynamics were carried out to evaluate diastolic function in sham, TAC, TAC+GFP and TAC+RLN2 groups. Then hearts were harvested for subsequent examinations. The results indicated that relaxin-2 had ameliorated diastolic function in the pressure-overloaded rats. Compared with the TAC and TAC+GFP groups, the relaxin-2 gene transfer increased phosphorylation of Akt at both the Ser473 and Thr308 sites. Meanwhile, it increased the Ser16 and Thr17- phosphorylation levels of phospholamban (PLB). Furthermore, SERCA2 activity was enhanced in the TAC+RLN2 group more than in the TAC and TAC+GFP groups. CONCLUSIONS: These results demonstrated that relaxin-2 gene therapy improved diastolic function in pressure-overloaded rats. The potential mechanism may be that relaxin-2 gene transfer enhances SERCA2 activity in hearts by increasing phospholamban phosphorylation through nuclear-targeted Akt phosphorylation.

Elevated soluble ST2 and depression increased the risk of all-cause mortality and hospitalization in patients with heart failure.

This study aimed to assess the predictive effect of soluble ST2 (sST2) and depressive symptoms in patients with heart failure (HF) and to determine whether the prognosis of HF patients with preserved ejection fraction (HFpEF) differs from those with reduced ejection fraction (HFrEF). A cohort of 233 HF patients was followed for 1 year. Depressive symptoms were evaluated by the Hospital Anxiety and Depression Scale. The primary endpoint was all-cause mortality and HF-related hospitalization. For the analysis of survival, the left ventricular ejection fraction (LVEF) cut-offs for defining HFpEF were set at 50%, 45%, and 40%, respectively. With increasing LVEF, levels of sST2 were gradually decreased (45.2 ng/mL, 35.8 ng/mL, and 32.1 ng/mL in patients with LVEF ≤ 40%, 41% to 49%, and ≥ 50%, respectively, P for trend < 0.001), as well as the prevalence of depressive symptoms (35.4%, 33.3%, and 20.4%, respectively, P for trend = 0.022). After 1-year follow-up, 128 patients (54.9%) achieved the primary endpoint and 47 patients (20.2%) died. Depressive symptoms were independent risk factors of all-cause mortality and HF-related hospitalization. The combined presence of elevated sST2 (> 36.0 ng/mL) and depressive symptoms was associated with a 4.9-fold increased risk of the primary endpoint. Regardless of LVEF cut-offs, the associated risk of adverse outcomes in HFpEF was as high as in HFrEF after adjustment for significant risk factors including sST2 and N-terminal pro-brain natriuretic peptide. In conclusion, depressive symptoms provided additional prognostic information to that of sST2 in HF patients. The prognosis of HFpEF patients was similar to that of HFrEF patients.