Interleukin-5 (IL-5) has been reported to be involved in cardiovascular diseases, such as atherosclerosis and cardiac injury. This study aimed to investigate the effects of IL-5 on cardiac remodelling. Mice were infused with angiotensin II (Ang II), and the expression and source of cardiac IL-5 were analysed. The results showed that cardiac IL-5 expression was time- and dose-dependently decreased after Ang II infusion, and was mainly derived from cardiac macrophages. Additionally, IL-5-knockout (IL-5-/-) mice were used to observe the effects of IL-5 knockout on Ang II-induced cardiac remodelling. We found knockout of IL-5 significantly increased the expression of cardiac hypertrophy markers, elevated myocardial cell cross-sectional areas and worsened cardiac dysfunction in Ang II-infused mice. IL-5 deletion also promoted M2 macrophage differentiation and exacerbated cardiac fibrosis. Furthermore, the effects of IL-5 deletion on cardiac remodelling was detected after the STAT3 pathway was inhibited by S31-201. The effects of IL-5 on cardiac remodelling and M2 macrophage differentiation were reversed by S31-201. Finally, the effects of IL-5 on macrophage differentiation and macrophage-related cardiac hypertrophy and fibrosis were analysed in vitro. IL-5 knockout significantly increased the Ang II-induced mRNA expression of cardiac hypertrophy markers in myocardial cells that were co-cultured with macrophages, and this effect was reversed by S31-201. Similar trends in the mRNA levels of fibrosis markers were observed when cardiac fibroblasts and macrophages were co-cultured. In conclusions, IL-5 deficiency promote the differentiation of M2 macrophages by activating the STAT3 pathway, thereby exacerbating cardiac remodelling in Ang II-infused mice. IL-5 may be a potential target for the clinical prevention of cardiac remodelling.

The goal of this study was to evaluate the intensity of autophagy and ubiquitin-dependent proteolysis processes occurring in myocardium of left ventricle (LV) in subsequent stages of pulmonary arterial hypertension (PAH) to determine mechanisms responsible for LV mass loss in a monocrotaline-induced PAH rat model. LV myocardium samples collected from 32 Wistar rats were analyzed in an early PAH group (n = 8), controls time-paired (n = 8), an end-stage PAH group (n = 8), and their controls (n = 8). Samples were subjected to histological analyses with immunofluorescence staining, autophagy assessment by western blotting, and evaluation of ubiquitin-dependent proteolysis in the LV by immunoprecipitation of ubiquitinated proteins. Echocardiographic, hemodynamic, and heart morphometric parameters were assessed regularly throughout the experiment. Considerable morphological and hemodynamic remodeling of the LV was observed over the course of PAH. The end-stage PAH was associated with significantly impaired LV systolic function and a decrease in LV mass. The LC3B-II expression in the LV was significantly higher in the end-stage PAH group compared to the early PAH group (p = 0.040). The measured LC3B-II/LC3B-I ratios in the end-stage PAH group were significantly elevated compared to the controls (p = 0.039). Immunofluorescence staining showed a significant increase in the abundance of LC3 puncta in the end-stage PAH group compared to the matched controls. There were no statistically significant differences in the levels of expression of all ubiquitinated proteins when comparing both PAH groups and matched controls. Autophagy may be considered as the mechanism behind the LV mass loss at the end stage of PAH.

Objective: To analyze the correlation between fatty liver index (FLI) and myocardial remodeling. Methods: For cross-sectional study, cluster sampling was used to conduct a follow-up study of \"Risk evaluation of cancers in Chinese diabetic individuals: A longitudinal (REACTION) study\" among communities of Gucheng and Pingguoyuan of Beijing from April 2015 to September 2015. According to the inclusion and exclusion criteria, 8 848 participants were selected. Biochemical indicators such as body mass index, waist circumference, triglycerides, and γ-glutamyl transpeptidase were detected to calculate the FLI. The correlation between FLI and myocardial remodeling was analyzed. Interventricular septal thickness (IVS), left atrial diameter (LAD), left ventricular end diastolic diameter (LVEDD), and the presence of diastolic dysfunction were measured by color doppler ultrasound. The participants were divided into Q1 group (FLI<30, 4 529 cases), Q2 group (30≤FLI<60, 2 762 cases), and Q3 group (FLI≥60, 1 557 cases) based on FLI levels. Single factor analysis of variance was used for inter-group comparison, logistic regression analysis was used to analyze the correlation between FLI and myocardial remodeling. Results: A total of 8 848 subjects were selected for the study (3 110 male and 5 738 female, mean age: 59.96 years). The IVS of Q1, Q2, and Q3 groups were (9.35±1.08), (9.73±1.22), and (10.07±1.31) mm, respectively. The LAD were (30.94±3.90), (33.37±4.12), and (34.98±4.47) mm, respectively. The LVEDD were (42.51±5.05), (44.43±5.10), and (46.06±5.52) mm, respectively. All increased with the increase of FLI (all P<0.001). FLI was an independent risk factor for IVS thickening, LAD increase, LVEDD increase, and diastolic function decrease. The respective risks for IVS thickening, LAD increase, LVEDD increase, and diastolic function decrease in a population with intermediate and higher FLI levels was 1.62 times (95%CI 1.39-1.89) and 2.53 times (95%CI 2.13-3.00); 2.71 times (95%CI 2.39-3.06) and 5.00 times (95%CI 4.12-6.08); 2.36 times (95%CI 1.85-3.00) and 4.33 times (95%CI 3.33-5.62); and 1.90 times (95%CI 1.63-2.19) and 1.95 times (95%CI 1.60-2.37) than those with lower FLI levels. Conclusion: There is a certain relevance between FLI and myocardial remodeling.
目的： 分析脂肪肝指数（FLI）与心肌重构的关联性。 方法： 横断面研究，2015年4至9月采取整群抽样的方法对北京古城及苹果园两个社区居民进行“中国2型糖尿病患者肿瘤发生风险的流行病学研究（REACTION）”的随访研究，根据纳入及排除标准，共筛选出8 848人为研究对象，获取体重指数、腰围、甘油三酯、γ-谷氨酰转移酶等生化指标，并计算FLI。彩色多普勒超声仪检测室间隔厚度（IVS）、左心房内径（LAD）、左心室舒张末期内径（LVEDD），以及是否存在舒张功能减退。根据FLI三分位数分为Q1组（FLI<30，4 529例），Q2组（30≤FLI<60，2 762例），Q3组（FLI≥60，1 557例）。采用单因素方差分析进行组间比较，采用logistic回归分析FLI与心肌重构的关联性。 结果： 8 848人中男性3 110人，女性5 738人，平均年龄59.96岁。Q1、Q2、Q3组IVS分别为（9.35±1.08）、（9.73±1.22）、（10.07±1.31）mm，LAD分别为（30.94±3.92）、（33.37±4.12）、（34.98±4.47）mm，LVEDD分别为（42.51±5.05）、（44.43±5.10）、（46.06±5.52）mm，总体上随着FLI的升高而升高（均P<0.001）。FLI是IVS增厚、LAD增宽、LVEDD增宽、舒张功能减退的独立危险因素，FLI Q2及Q3组人群发生IVS增厚、LAD增宽、LVEDD增宽、舒张功能减退的风险分别是Q1组人群的1.62倍（95%CI 1.39~1.89）及2.53倍（95%CI 2.13~3.00）、2.71倍（95%CI 2.39~3.06）及5.00倍（95%CI 4.12~6.08）、2.36倍（95%CI 1.85~3.00）及4.33倍（95%CI 3.33~5.62）、1.90倍（95%CI 1.63~2.19）及1.95倍（95%CI 1.60~2.37）。 结论： FLI与心肌重构的出现有一定关联性。.

Biological sex is an important modifier of physiology and influences pathobiology in many diseases. While heart disease is the number one cause of death worldwide in both men and women, sex differences exist at the organ and cellular scales, affecting clinical presentation, diagnosis, and treatment. In this Review, we highlight baseline sex differences in cardiac structure, function, and cellular signaling and discuss the contribution of sex hormones and chromosomes to these characteristics. The heart is a remarkably plastic organ and rapidly responds to physiological and pathological cues by modifying form and function. The nature and extent of cardiac remodeling in response to these stimuli are often dependent on biological sex. We discuss organ- and molecular-level sex differences in adaptive physiological remodeling and pathological cardiac remodeling from pressure and volume overload, ischemia, and genetic heart disease. Finally, we offer a perspective on key future directions for research into cardiac sex differences.

Aerobic training (AT), an effective form of cardiac rehabilitation, has been shown to be beneficial for cardiac repair and remodeling after myocardial infarction (MI). The p300/CBP-associated factor (PCAF) is one of the most important lysine acetyltransferases and is involved in various biological processes. However, the role of PCAF in AT and AT-mediated cardiac remodeling post-MI has not been determined. Here, we found that the PCAF protein level was significantly increased after MI, while AT blocked the increase in PCAF. AT markedly improved cardiac remodeling in mice after MI by reducing endoplasmic reticulum stress (ERS). In vivo, similar to AT, pharmacological inhibition of PCAF by Embelin improved cardiac recovery and attenuated ERS in MI mice. Furthermore, we observed that both IGF-1, a simulated exercise environment, and Embelin protected from H2O2-induced cardiomyocyte injury, while PCAF overexpression by viruses or the sirtuin inhibitor nicotinamide eliminated the protective effect of IGF-1 in H9C2 cells. Thus, our data indicate that maintaining low PCAF levels plays an essential role in AT-mediated cardiac protection, and PCAF inhibition represents a promising therapeutic target for attenuating cardiac remodeling after MI.

Rationale: Device implantation frequently triggers cardiac remodeling and fibrosis, with monocyte-driven inflammatory responses precipitating arrhythmias. This study investigates the role of m6A modification enzymes METTL3 and METTL14 in these responses and explores a novel therapeutic strategy targeting these modifications to mitigate cardiac remodeling and fibrosis. Methods: Peripheral blood mononuclear cells (PBMCs) were collected from patients with ventricular septal defects (VSD) who developed conduction blocks post-occluder implantation. The expression of METTL3 and METTL14 in PBMCs was measured. METTL3 and METTL14 deficiencies were induced to evaluate their effect on angiotensin II (Ang II)-induced myocardial inflammation and fibrosis. m6A modifications were analyzed using methylated RNA immunoprecipitation followed by quantitative PCR. NF-κB pathway activity and levels of monocyte migration and fibrogenesis markers (CXCR2 and TGF-β1) were assessed. An erythrocyte microvesicle-based nanomedicine delivery system was developed to target activated monocytes, utilizing the METTL3 inhibitor STM2457. Cardiac function was evaluated via echocardiography. Results: Significant upregulation of METTL3 and METTL14 was observed in PBMCs from patients with VSD occluder implantation-associated persistent conduction block. Deficiencies in METTL3 and METTL14 significantly reduced Ang II-induced myocardial inflammation and fibrosis by decreasing m6A modification on MyD88 and TGF-β1 mRNAs. This disruption reduced NF-κB pathway activation, lowered CXCR2 and TGF-β1 levels, attenuated monocyte migration and fibrogenesis, and alleviated cardiac remodeling. The erythrocyte microvesicle-based nanomedicine delivery system effectively targeted inflamed cardiac tissue, reducing inflammation and fibrosis and improving cardiac function. Conclusion: Inhibiting METTL3 and METTL14 in monocytes disrupts the NF-κB feedback loop, decreases monocyte migration and fibrogenesis, and improves cardiac function. Targeting m6A modifications of monocytes with STM2457, delivered via erythrocyte microvesicles, reduces inflammation and fibrosis, offering a promising therapeutic strategy for cardiac remodeling associated with device implantation.

BACKGROUND: Obesity is a significant risk factor for heart failure with preserved ejection fraction (HFpEF). In this study, we explore the relationships between body mass index (BMI) and adipose tissue compartments such as visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and epicardial adipose tissue (EAT), with respect to left ventricular (LV) structure and function in subjects with preserved LV systolic function.
METHODS: Between January and December 2020, this retrospective study included 749 participants who exhibited preserved LV systolic function and underwent transthoracic echocardiography along with abdominal computed tomography. LV structural and functional variables as well as EAT, VAT, and SAT thickness were evaluated using echocardiography and computed tomography.
RESULTS: SAT decreased, while VAT and EAT progressively increased with age. There were significant correlations between BMI and various adipose tissues, with the strongest correlation observed with SAT (r = .491, p < .001) compared to VAT (r = .371, p < .001) or EAT (r = .135, p < .001). However, EAT demonstrated the most substantial association with decreased LV end-diastolic dimension, LV end-systolic dimension, and septal mitral annular velocity and increased relative wall thickness (all p < .05), while VAT and SAT did not show significant associations with LV remodeling and functional parameters after adjusting for clinical variables.
CONCLUSIONS: EAT is the most critical adipose tissue influencing LV geometric and functional changes, compared with VAT or SAT. Thick EAT is associated small LV chamber size, concentric remodeling, and relaxation abnormalities.

BACKGROUND: Ubiquitin-specific protease 38 (USP38), belonging to the USP family, is recognized for its role in controlling protein degradation and diverse biological processes. Ventricular arrhythmias (VAs) following heart failure (HF) are closely linked to ventricular electrical remodeling, yet the specific mechanisms underlying VAs in HF remain inadequately explored. In this study, we examined the impact of USP38 on VAs in pressure overload-induced HF.
METHODS: Cardiac-specific USP38 knockout mice, cardiac-specific USP38 transgenic mice and their matched control littermates developed HF induced by aortic banding (AB) surgery. After subjecting the mice to AB surgery for a duration of four weeks, comprehensive investigations were conducted, including pathological analysis and electrophysiological assessments, along with molecular analyses.
RESULTS: We observed increased USP38 expression in the left ventricle of mice with HF. Electrocardiogram showed that the USP38 knockout shortened the QRS interval and QTc, while USP38 overexpression prolonged these parameters. USP38 knockout decreased the susceptibility of VAs by shortening action potential duration (APD) and prolonging effective refractory period (ERP). In addition, USP38 knockout increased ion channel and Cx43 expression in ventricle. On the contrary, the increased susceptibility of VAs and the decreased expression of ventricular ion channels and Cx43 were observed with USP38 overexpression. In both in vivo and in vitro experiments, USP38 knockout inhibited TBK1/AKT/CAMKII signaling, whereas USP38 overexpression activated this pathway.
CONCLUSIONS: Our data indicates that USP38 increases susceptibility to VAs after HF through TBK1/AKT/CAMKII signaling pathway, Consequently, USP38 may emerge as a promising therapeutic target for managing VAs following HF.

The association of postpartum cardiac reverse remodeling (RR) with urinary proteome, particularly in pregnant women with cardiovascular (CV) risk factors who show long-term increased risk of cardiovascular disease and mortality is unknown. We aim to profile the urinary proteome in pregnant women with/without CV risk factors to identify proteins associated with postpartum RR. Our study included a prospective cohort of 32 healthy and 27 obese and/or hypertensive and/or diabetic pregnant women who underwent transthoracic echocardiography, pulse-wave-velocity, and urine collection at the 3rd trimester and 6 months postpartum. Shotgun HPLC-MS/MS profiled proteins. Generalized linear mixed-effects models were used to identify associations between urinary proteins and left ventricle mass (LVM), a surrogate of RR. An increase in arterial stiffness was documented from 3rd trimester to 6 months after delivery, being significantly elevated in women with CV risk factors. In addition, the presence of at least one CV risk factor was associated with worse LVM RR. We identified 6 and 11 proteins associated with high and low LVM regression, respectively. These proteins were functionally linked with insulin-like growth factor (IGF) transport and uptake regulation by IGF binding-proteins, platelet activation, signaling and aggregation and the immune system\'s activity. The concentration of IGF-1 in urine samples was associated with low LVM regression after delivery. Urinary proteome showed a predicting potential for identifying pregnant women with incomplete postpartum RR.

BACKGROUND: The regenerative capacity of the adult mammalian hearts is limited. Numerous studies have explored mechanisms of adult cardiomyocyte cell-cycle withdrawal. This translational study evaluated the effects and underlying mechanism of rhCHK1 (recombinant human checkpoint kinase 1) on the survival and proliferation of cardiomyocyte and myocardial repair after ischemia/reperfusion injury in swine.
RESULTS: Intramyocardial injection of rhCHK1 protein (1 mg/kg) encapsulated in hydrogel stimulated cardiomyocyte proliferation and reduced cardiac inflammation response at 3 days after ischemia/reperfusion injury, improved cardiac function and attenuated ventricular remodeling, and reduced the infarct area at 28 days after ischemia/reperfusion injury. Mechanistically, multiomics sequencing analysis demonstrated enrichment of glycolysis and mTOR (mammalian target of rapamycin) pathways after rhCHK1 treatment. Co-Immunoprecipitation (Co-IP) experiments and protein docking prediction showed that CHK1 (checkpoint kinase 1) directly bound to and activated the Serine 37 (S37) and Tyrosine 105 (Y105) sites of PKM2 (pyruvate kinase isoform M2) to promote metabolic reprogramming. We further constructed plasmids that knocked out different CHK1 and PKM2 amino acid domains and transfected them into Human Embryonic Kidney 293T (HEK293T) cells for CO-IP experiments. Results showed that the 1-265 domain of CHK1 directly binds to the 157-400 amino acids of PKM2. Furthermore, hiPSC-CM (human iPS cell-derived cardiomyocyte) in vitro and in vivo experiments both demonstrated that CHK1 stimulated cardiomyocytes renewal and cardiac repair by activating PKM2 C-domain-mediated cardiac metabolic reprogramming.
CONCLUSIONS: This study demonstrates that the 1-265 amino acid domain of CHK1 binds to the 157-400 domain of PKM2 and activates PKM2-mediated metabolic reprogramming to promote cardiomyocyte proliferation and myocardial repair after ischemia/reperfusion injury in adult pigs.