Cardiac ankyrin repeat protein contributes to dilated cardiomyopathy and heart failure.

Cardiac ankyrin repeat protein (CARP) is a cardiac-specific stress-response protein which exerts diverse effects to modulate cardiac remodeling in response to pathological stimuli. We examined the role of CARP in postnatal cardiac development and function under basal conditions in mice. Transgenic mice that selectively overexpressed CARP in heart (CARP Tg) exhibited dilated cardiac chambers, impaired heart function, and cardiac fibrosis as assessed by echocardiography and histological staining. Furthermore, the mice had a shorter lifespan and reduced survival rate in response to ischemic acute myocardial infarction. Immunofluorescence demonstrated the overexpressed CARP protein was predominantly accumulated in the nuclei of cardiomyocytes. Microarray analysis revealed that the nuclear localization of CARP was associated with the suppression of calcium-handling proteins. In vitro experiments revealed that CARP overexpression resulted in decreased cell contraction and calcium transient. In post-mortem cardiac specimens from patients with dilated cardiomyopathy and end-stage heart failure, CARP was significantly increased. Taken together, our data identified CARP as a crucial contributor in dilated cardiomyopathy and heart failure which was associated with its regulation of calcium-handling proteins.

CCL7 contributes to angiotensin II-induced abdominal aortic aneurysm by promoting macrophage infiltration and pro-inflammatory phenotype.

Chemokine C-C motif ligand 7 (CCL7), a member of CC chemokine subfamily, plays pivotal roles in numerous inflammatory diseases. Hyper-activation of inflammation is an important characteristic of abdominal aortic aneurysm (AAA). Therefore, in the present study, we aimed to determine the effect of CCL7 on AAA formation. CCL7 abundance in aortic tissue and macrophage infiltration were both increased in angiotensin II (Ang II)-induced AAA mice. Ex vivo, CCL7 promoted macrophage polarization towards M1 phenotype. This effect was reversed by the blockage of CCR1, a receptor of CCL7. CCL7 up-regulated JAK2/STAT1 protein level in macrophage, and CCL7-induced M1 activation was suppressed by JAK2/STAT1 pathway inhibition. To verify the effect of CCL7 on AAA in vivo, either CCL7-neutralizing antibody (CCL7-nAb) or vehicles were intraperitoneally injected 24 hours prior to Ang II infusion and subsequently every three days for 4 weeks. CCL7-nAb administration significantly attenuated Ang II-induced luminal and external dilation as well as pathological remodelling. Immunostaining showed that CCL7-nAb administration significantly decreased aneurysmal macrophage infiltration. In conclusion, CCL7 contributed to Ang II-induced AAA by promoting M1 phenotype of macrophage through CCR1/JAK2/STAT1 signalling pathway.

Angiotensinogen and Megalin Interactions Contribute to Atherosclerosis-Brief Report.

Objective- AGT (Angiotensinogen) is the unique precursor of the renin-angiotensin system that is sequentially cleaved by renin and ACE (angiotensin-converting enzyme) to produce Ang II (angiotensin II). In this study, we determined how these renin-angiotensin components interact with megalin in kidney to promote atherosclerosis. Approach and Results- AGT, renin, ACE, and megalin were present in the renal proximal convoluted tubules of wild-type mice. Hepatocyte-specific AGT deficiency abolished AGT protein accumulation in proximal tubules and diminished Ang II concentrations in kidney, while renin was increased. Megalin was most abundant in kidney and exclusively present on the apical side of proximal tubules. Inhibition of megalin by antisense oligonucleotides (ASOs) led to ablation of AGT and renin proteins in proximal tubules, while leading to striking increases of urine AGT and renin concentrations, and 70% reduction of renal Ang II concentrations. However, plasma Ang II concentrations were unaffected. To determine whether AGT and megalin interaction contributes to atherosclerosis, we used both male and female low-density lipoprotein receptor-/- mice fed a saturated fat-enriched diet and administered vehicles (PBS or control ASO) or megalin ASO. Inhibition of megalin did not affect plasma cholesterol concentrations, but profoundly reduced atherosclerotic lesion size in both male and female mice. Conclusions- These results reveal a regulatory role of megalin in the intrarenal renin-angiotensin homeostasis and atherogenesis, positing renal Ang II to be an important contributor to atherosclerosis that is mediated through AGT and megalin interactions.

The impact of growth differentiation factor 15 on the risk of cardiovascular diseases: two-sample Mendelian randomization study.

BACKGROUND: Growth differentiation factor 15 (GDF-15), a stress responsive cytokine, belongs to transforming growth factor ß cytokine superfamily. Some evidence support that it's involved in inflammation, coagulation, oxidative stress, endothelial dysfunction, and hemostasis. However, it's still controversial whether GDF-15 directly contributes to the morbidity and mortality of patients suffered with cardiovascular disease (CVD). Besides prospective cohort study and randomized controlled trial, Mendelian randomization (MR) is a genetic epidemiological method that exploits genetic variants as unbiased proxies for modifiable to determine the causal relationships between exposures and health outcomes. Herein, we introduced a two-sample MR approach to evaluate the causal relationships of circulating GDF-15 levels with major CVDs incidence. METHODS: Genetic instruments and summary statistics for two-sample MR analysis were obtained from 5 independent large genome-wide association studies (GWAS) to investigate the causal correlation between circulating GDF-15 levels and 9 CVDs, respectively. Conventional inverse variance weighted method was adopted to evaluate the causality of GDF-15 with different outcomes; weighted median and MR egger were used for sensitivity analyses. RESULTS: Among 9 SNPs identified from 5 GWASs in 2.6 million individuals, 5 SNPs (rs1227731, rs3195944, rs17725099, rs888663, rs749451) coming from chromosome 19 and containing the PGPEP1 and GDF-15 genes were employed. Based on the instruments, circulating GDF-15 levels significantly linked to the increased risk of cardioembolic stroke, atrial fibrillation, coronary artery disease and myocardial infarction. However, no significant causal association was observed for circulating GDF-15 levels with the incidence of any ischemic stroke, large-artery atherosclerotic stroke, small vessel stroke, heart failure and nonischemic cardiomyopathy. CONCLUSIONS: The MR study provides with genetic evidence for the causal relationship of circulating GDF-15 levels with the increased risk of cardioembolic stroke, atrial fibrillation, coronary artery disease and myocardial infarction, but not any ischemic stroke, large-artery atherosclerotic stroke, small vessel stroke, heart failure and nonischemic cardiomyopathy. It indicates that GDF-15 might be a promising biomarker or potential therapeutic target for some CVDs.

Cardiac ankyrin repeat protein attenuates cardiomyocyte apoptosis by upregulation of Bcl-2 expression.

Cardiac ankyrin repeat protein (CARP) is a nuclear transcriptional co-factor that has additional functions in the myoplasm as a component of the muscle sarcomere. Previous studies have demonstrated increased expression of CARP in cardiovascular diseases, however, its role in cardiomyocyte apoptosis is unclear and controversial. In the present study, we investigated possible roles of CARP in hypoxia/reoxygenation (H/R) -induced cardiomyocyte apoptosis and the underlying mechanisms. Neonatal mouse ventricular cardiomyocytes were isolated and infected with adenovirus encoding Flag-tagged CARP (Ad-CARP) and lentivirus encoding CARP targeted shRNA (sh-CARP), respectively. Cardiomyocyte apoptosis induced by exposure to H/R conditions was evaluated by TUNEL staining and western blot analysis of cleaved caspase-3. The results showed that H/R-induced apoptosis was significantly decreased in Ad-CARP cardiomyocytes and increased in sh-CARP cardiomyocytes, suggesting a protective anti-apoptosis role for CARP. Interestingly, over-expressed CARP was mainly distributed in the nucleus, consistent with its role in regulating transcriptional activity. qPCR analysis showed that Bcl-2 transcripts were significantly increased in Ad-CARP cardiomyocytes. ChIP and co-IP assays confirmed the binding of CARP to the Bcl-2 promoter through interaction with transcription factor GATA4. Collectively, our results suggest that CARP can protect against H/R induced cardiomyocyte apoptosis, possibly through increasing anti-apoptosis Bcl-2 gene expression.

Burden of Aortic Aneurysm and Its Attributable Risk Factors from 1990 to 2019: An Analysis of the Global Burden of Disease Study 2019.

Background: Global and national estimates on the epidemiology of aortic aneurysms are prerequisites for disease management and policymaking. Based on the Global Burden of Disease (GBD) 2019, this study aimed to discern the global aortic aneurysm burden by systematically analyzing demographic data on mortality and exploring the attributable risks and relevant factors. Methods: The data analyzed in this study were available in the Global Health Data Exchange (GHDx) online query tool. The population in our study comprised individuals from 204 countries and territories from 1990 to 2019. The estimated annual percentage changes (EAPCs) were performed to assess the temporal trends of aortic aneurysms and their attributable risks. Spearman correlation analysis was performed to explore the relationship between the burden of aortic aneurysm and covariates. Results: Although aortic aneurysm-related deaths (82.1%) and disability-adjusted life years (DALYs) (67%) increased from 1990 to 2019, the global trend of age-standardized rate of death (ASRD) (EAPC: -1.34, 95% CI = -1.46 to -1.22, P < 0.001) and age-standardized rate of DALY (ASDALYR) (EAPC: -1.06, 95% CI = -1.17 to -0.95, P < 0.001) decreased, both of which presented age dependence and gender differences. Smoking and high systolic blood pressure (SBP) were the main attributable risks of disease burden and tend to decease globally (EAPC: -1.89, 95% CI = -2.03 to -1.89, P < 0.001; -1.31 95% CI = -1.43 to -1.19, P < 0.001, respectively). Alcohol abstinence (male: R = -0.71, P < 0.001; female: R = -0.73, P < 0.001), smoking age of initiation (male: R = -0.32, P < 0.001; female: R = -0.50, P < 0.001), physical activity (male: R = -0.50, P < 0.001; female: R = -0.55, P < 0.001), and mean temperature (R = -0.62, P < 0.001) had negative correlation with ASRD. However, cholesterol level (male: R = 0.62, P < 0.001; female: R = 0.39, P < 0.001), body mass index (BMI) (male: R = 0.30, P < 0.001; female R = -0.01, P > 0.05), and alcohol consumption (male: R = 0.46, P < 0.001; female: R = 0.42, P < 0.001) had a positive correlation with ASRM. Besides, standard of living and medical resources positively related to burden of aortic aneurysm. Conclusion: In this study, a decreasing trend of aortic aneurysm burden was found globally, especially in advanced regions. Aged men who smoke and women who have hypertension should pay close attention to, particularly in deprived economic groups, and many approaches can be performed to reduce the burden of aortic aneurysms.

Lipocalin-2 in neutrophils induces ferroptosis in septic cardiac dysfunction via increasing labile iron pool of cardiomyocytes.

Cardiac dysfunction is a common complication of sepsis with high mortality. The present study was designed to identify the effect of neutrophil-derived lipocalin-2 (LCN2) in septic cardiac dysfunction (SCD) and its potential mechanism. Wild-type (WT) and LCN2-knockout (LCN2 KO) mice were peritoneally injected with lipopolysaccharide (LPS) to induce SCD. The cardiac function was assessed 12 h after LPS injection by echocardiography. Cardiac tissue was harvested for the evaluation of malonaldehyde (MDA) and prostaglandin E synthase 2 (PTGS2) mRNA levels. LPS induced ferroptosis and SCD in mice. LCN2 deficiency attenuated cardiac injury post-LPS administration. In vitro, LCN2 expression in neutrophils increased in response to LPS. Ferroptosis of cardiomyocytes induced by conditioned medium (CM) from LPS-induced neutrophils of WT mice could be attenuated in CM from LPS-induced neutrophils of LCN2 KO mice. Exogenous LCN2 induced H9C2 cell ferroptosis via increasing labile iron pool (LIP). In conclusion, our results showed that LCN2 deficiency prevented heart dysfunction and ferroptosis in SCD mice and suggested that neutrophil-derived LCN2 might be a promising therapeutic target for SCD.

CXCR4-dependent macrophage-to-fibroblast signaling contributes to cardiac diastolic dysfunction in heart failure with preserved ejection fraction.

Rationale: Heart failure with preserved ejection fraction (HFpEF) can arise from hypertension-induced cardiac remodeling. Monocyte/macrophage accumulation and inflammation are crucial elements in the pathogenesis of hypertension-induced cardiac remodeling. The C-X-C chemokine receptor 4 (CXCR4) is a critical regulator of the macrophage-mediated immune response. Nevertheless, the contribution of CXCR4 to macrophage phenotype and function during the progression of HFpEF remains unclear. Herein, we aimed to determine the role of macrophagic CXCR4 in heart failure with preserved ejection fraction (HFpEF). Methods: As a HFpEF model, wild type mice and myeloid-specific CXCR4 deficiency mice were subjected to pressure overload for 30 days to assess the function of macrophagic CXCR4 on cardiac function. Medium from macrophages was used to treat cardiac fibroblasts to study macrophage-to-fibroblast signaling. Results: We found circulatory CXCR4+ immune cells, mainly monocytes, markedly increased in HFpEF patients with hypertension. In the experimental HFpEF mice model, macrophages but not neutrophils represent the main infiltrating inflammatory cells in the heart, abundantly expressing CXCR4. Myeloid-specific CXCR4 deficient impeded macrophage infiltration and inflammatory response in the heart of HFpEF mice, thus ameliorating cardiac fibrosis and improving cardiac diastolic function. Furthermore, transcriptomic profiling data revealed that CXCR4 loss in macrophages exhibited a decreased transcriptional signature associated with the regulation of inflammatory response. Notably, CXCR4 significantly augmented chemokine (C­X­C) motif ligand (CXCL3) expression, which at least partly contributed to fibrosis by promoting myofibroblast differentiation. Mechanistically, the increased production of pro-inflammatory cytokines in CXCR4 expressed macrophages could be attributed to the suppression of the peroxisome proliferator-activated receptor γ (PPARγ) activity. Conclusions: Collectively, our data supported that the infiltration of CXCR4+ macrophages in the heart exacerbates hypertension-induced diastolic function by promoting pro-inflammatory cytokines production and thus may serve as a potential therapeutic target for hypertension-induced HFpEF.

Sustained-Release Ivabradine Hemisulfate in Patients With Systolic Heart Failure.

BACKGROUND: Ivabradine has potent actions in reducing heart rate and improving clinical outcomes of chronic heart failure with reduced ejection fraction (HFrEF). At present, only the short-acting formulation of ivabradine is available that needs to be administered twice daily. OBJECTIVES: This study sought to evaluate the role of ivabradine hemisulfate sustained release (SR), a novel long-acting formulation of ivabradine dosed once daily, in stable patients with HFrEF. METHODS: Patients with stabilized HFrEF in New York Heart Association functional class II-IV were enrolled and randomized to receive placebo or ivabradine SR in addition to standard medications. The primary endpoint was the change of left ventricular (LV) end-systolic volume index from baseline to week 32. RESULTS: We randomly assigned 181 patients to placebo and 179 patients to ivabradine SR. After 32 weeks, a significant improvement of LV end-systolic volume index from baseline was observed in both arms with a greater effect in the ivabradine SR arm. Ivabradine SR therapy also exhibited superiority in improving LV end-diastolic volume index, LV ejection fraction, resting heart rate, the Kansas City Cardiomyopathy Questionnaire score, and hospital admission for heart failure worsening and cardiovascular disease in comparison to placebo. Overall adverse events showed no difference between the treatment arms. There were fewer occurrences of worsening heart failure in the ivabradine SR arm. CONCLUSIONS: The present study demonstrates that ivabradine SR once daily in addition to optimum standard therapy improved heart function in patients with HFrEF. (Clinical Trial of Systolic Heart Failure Treatment of IvabRadine Hemisulfate Sustained-release Tablets [FIRST]; NCT02188082).

Sex-Specific Genetically Predicted Iron Status in relation to 12 Vascular Diseases: A Mendelian Randomization Study in the UK Biobank.

BACKGROUND: Iron overload has been implicated in the pathogenesis of varicose veins (VVs). However, the association of serum iron status with other vascular diseases (VDs) is not well understood, which might be a potential target for VD prevention. This study was aimed at investigating the causal associations between iron status and VDs using the Mendelian randomization (MR) method. METHODS: A two-sample MR was designed to investigate whether iron status was associated with VDs, based on iron data from a published genome-wide association study meta-analysis of 48,972 subjects of European descent and VD data obtained from the UK Biobank, including 361,194 British subjects (167,020 males and 194,174 females). We further explored whether there was sex difference in the associations between genetically predicted iron status and VDs. RESULTS: The results demonstrated that iron status had a significant causal effect on VVs of lower extremities (P < 0.001) and a potential effect on coronary atherosclerosis (P < 0.05 for serum iron, ferritin, and transferrin saturation, respectively), but not on other VDs. Furthermore, higher iron status exerted a detrimental effect on VVs of lower extremities in both genders (P < 0.05) and a protective effect on male patients with coronary atherosclerosis (P < 0.05 for serum iron, ferritin, and transferrin saturation, respectively). CONCLUSIONS: This MR study provides robust evidence that higher iron status increases the risk of VVs of lower extremities, whereas it reduces the incidence of coronary atherosclerosis in the male population, which indicates that iron has divergent effects on vascular pathology.

Induction of thoracic aortic dissection: a mini-review of ß-aminopropionitrile-related mouse models.

Thoracic aortic dissection (TAD) is one of the most lethal aortic diseases due to its acute onset, rapid progress, and high rate of aortic rupture. The pathogenesis of TAD is not completely understood. In this mini-review, we introduce three emerging experimental mouse TAD models using ß-aminopropionitrile (BAPN) alone, BAPN for a prolonged duration (four weeks) and then with added infusion of angiotensin II (AngII), or co-administration of BAPN and AngII chronically. We aim to provide insights into appropriate application of these three mouse models, thereby enhancing the understanding of the molecular mechanisms of TAD.