m6A regulator-mediated RNA methylation modification remodels immune microenvironment in dilated cardiomyopathy.

The latest evidence suggested that the onset of dilated cardiomyopathy (DCM) is closely associated with immune microenvironment disturbance. Since N6 -methyladenosine (m6A) RNA methylation impacts on immunocyte function and antitumor immunity, it is predictable that m6A RNA methylation may result in immune microenvironment disorder. Here, we attempted to verify this hypothesis. We used single-sample gene set enrichment analysis (ssGSEA) to investigate the infiltration abundance of immunocytes, single-cell RNA-Seq to identify key m6A regulator, and a doxorubicin (Dox)-induced DCM mouse model to confirm our findings. ssGSEA revealed a higher infiltration abundance of CD8+ T lymphocytes, NK cells, monocytes, and B+ lymphocytes in DCM myocardium tissue. Single-cell RNA-Seq indicated a critical role of IGFBP2 in DCM. Cross-checking analysis hinted an interaction between IGFBP2 and NSUN5, ALYREF, RRP8, and ALKBH3. Mechanically, IGFBP2-mediated RNA methylation deteriorated the immune microenvironment and thus increased the risk of DCM by enhancing CD8+ T lymphocyte, NK cell, monocyte, B+ lymphocyte infiltration and activating check-point, MHC-I, and T cell co-stimulation signaling pathways. In the DCM mouse model, echocardiography indicated a significant reduction in ejection fraction (EF) and fractional shortening (FS) and an increase in left ventricular internal dimensions at systole (LVIDs) and diastole (LVIDd). MASSON staining indicated an increased fibrosis in myocardium tissue. qPCR and immunofluorescence staining indicated a significant increase in mRNA and protein levels of IGFBP2. The present study indicated that IGFBP2-mediated RNA methylation remodeled the immune microenvironment and increased the risk of DCM. IGFBP2 may serve as potential therapeutic target for DCM.

Exploration of dilated cardiomyopathy for biomarkers and immune microenvironment: evidence from RNA-seq.

BACKGROUND: The pathogenic mechanism of dilated cardiomyopathy (DCM) remains to be defined. This study aimed to identify hub genes and immune cells that could serve as potential therapeutic targets for DCM. METHODS: We downloaded four datasets from the Gene Expression Omnibus (GEO) database: GSE141910, GSE3585, GSE42955 and GSE79962. Weighted gene coexpression network analysis (WGCNA) and differential expression analysis were performed to identify gene panels related to DCM. Meanwhile, the CIBERSORT algorithm was used to estimate the immune cells in DCM tissues. Multiple machine learning approaches were used to screen the hub genes and immune cells. Finally, the diagnostic value of the hub genes was assessed by receiver operating characteristic (ROC) analysis. An experimental mouse model of dilated cardiomyopathy was used to validate the bioinformatics results. RESULTS: FRZB and EXT1 were identified as hub biomarkers, and the ROC curves suggested an excellent diagnostic ability of the above genes for DCM. In addition, naive B cells were upregulated in DCM tissues, while eosinophils, M2 macrophages, and memory CD4 T cells were downregulated in DCM tissues. The increase in two hub genes and naive B cells was validated in animal experiments. CONCLUSION: These results indicated that FRZB and EXT1 could be used as promising biomarkers, and eosinophils, M2 macrophages, resting memory CD4 T cells and naive B cells may also affect the occurrence of DCM.

The Clinical Characteristics and Risk Factors of Severe COVID-19.

OBJECTIVE: We aim to investigate the clinical characteristics and risk factors for the severe cases of coronavirus disease 2019 (COVID-19) in comparison with the non-severe patients. METHODS: We searched PubMed, EMBASE, Web of Science, and CNKI to collect all relevant studies published before July 26, 2020, and a total of 30 papers were included in this meta-analysis. RESULTS: In the severe COVID-19 patients, 60% (95% CI = 56-64%) were male, 25% (95% CI = 21-29%) were over 65 years old, 34% (95% CI = 24-44%) were obese, and 55% (95% CI = 41-70%) had comorbidities. The most prevalent comorbidities were hypertension (34%, 95% CI = 25-44%), diabetes (20%, 95% CI = 15-25%), and cardiovascular disease (CVD; 12%, 95% CI = 9-16%). The most common blood test abnormalities were elevated C-reactive protein (CRP; 87%, 82-92%), decreased lymphocyte count (68%, 58-77%), and increased lactate dehydrogenase (69%, 95% CI = 57-81%). In addition, abnormal laboratory findings revealing organ dysfunctions were frequently observed in the severe cases, including decrease in albumin (43%, 95% CI = 24-63%) and increase in aspartate aminotransferase (47%, 95% CI = 38-56%), alanine aminotransferase (28%, 95% CI = 16-39%), troponin I/troponin T (TnI/TnT; 29%, 95% CI = 13-45%), and serum Cr (SCr; 10%, 95% CI = 5-15%). CONCLUSION: The male, elderly and obese patients and those with any comorbidities, especially with hypertension, diabetes, and CVD, were more likely to develop into severe cases. But the association between hypertension, diabetes, CVD, and severity of COVID-19 was declined by the increase of age. A significant elevation in cardiac TnI/TnT, the hepatic enzymes, and SCr and the reduction in lymphocytes with elevated CRPs are important markers for the severity. Specific attention should be given to the elderly male and obese patients and those with indications of severe immune injury in combination with bacterial infection and indication of multi-organ dysfunction or damages.

Right ventricular contractility as a potential independent evaluation parameter in pulmonary hypertension.

BACKGROUND: Pulmonary artery hypertension (PAH) is a common disease with high disability and mortality rates, and can lead to right heart failure. We aimed to evaluate the capability of right ventricular pressure-volume coupling parameters, end-systolic elastance (Ees), right ventricular afterload (Ea), and arterial elastance (Ees/Ea) for assessing right ventricular performance during the chronic development of PAH. METHODS: Thirty-six PAH patients were enrolled in this study. We reported the cutoff values of the right ventricular pressure-volume coupling parameters in the progression of PAH and their relations with other pressure-volume loop measurements in both the right and left ventricles. RESULTS: Ees and normalised Ees (Ees/Ea) calculated from the pressure method performed better than ones from the volume method in correlation with mean pulmonary arterial pressure and mean right arterial pressure. The cutoff sets of Ees and Ees/Ea were capable of grouping pulmonary hypertension patients which were well supported by their significant correlation with several key right ventricular hemodynamic parameters. Additionally, the normalised Ees was able to reflect the changes in left ventricular function during the deterioration of PAH. CONCLUSION: Ees and Ees/Ea are promising independent reference parameters for assessing ventricular function in progressing PAH patients.

Kv4.3 expression abrogates and reverses norepinephrine-induced myocyte hypertrophy by CaMKII inhibition.

BACKGROUND: Down-regulation of Kv4.3 protein is a general feature of cardiac hypertrophy. Based on our recent studies, we propose that Kv4.3 reduction may be a hypertrophic stimulator. OBJECTIVE: We tested whether Kv4.3 expression can prevent or reverse cardiac hypertrophy induced by norepinephrine (NE). METHODS AND RESULTS: Incubation of 20 µM NE in cultured neonatal rat ventricular myocytes (NRVMs) for 48 h and 96 h induced myocyte hypertrophy in a time-dependent manner, characterized by progressive increase in cell size, protein/DNA ratio, ANP and BNP, along with an progressive increase in the activity of CaMKII and calcineurin and reduction of Kv4.3 mRNA and proteins. Interestingly, PKA-dependent phosphorylation of phospholamban (PLB) at Ser16 was increased at 48 h but reduced to the basal level at 96 h NE incubation. CaMKII inhibitors KN93 and AIP blunted NE-induced hypertrophic response and caused regression of hypertrophy, which is associated with a reduction of CaMKII activity and calcineurin expression. Kv4.3 expression completely suppressed the development of NE-induced hypertrophy and led to a regression in the hypertrophic myocytes. These effects were accompanied by a reduction in CaMKII autophosphorylation, PLB phosphorylation at Thr-17 without changing PLB phosphorylation at Ser-16. NFATc3 was also reduced by Kv4.3 expression. CONCLUSIONS: Our results demonstrated that Kv4.3 reduction is an important mediator in cardiac hypertrophy development via excessive CaMKII activation and that Kv4.3 expression is likely a potential therapeutic strategy for prevention and reversion of adrenergic stress-induced cardiac hypertrophy.

Identification of functional lncRNAs in atrial fibrillation by integrative analysis of the lncRNA-mRNA network based on competing endogenous RNAs hypothesis.

A mounting body of evidence has suggested that long noncoding RNAs (lncRNAs) play critical roles in human diseases by acting as competing endogenous RNAs (ceRNAs). However, the functions and ceRNA mechanisms of lncRNAs in atrial fibrillation (AF) remain to date unclear. In this study, we constructed an AF-related lncRNA-mRNA network (AFLMN) based on ceRNA theory, by integrating probe reannotation pipeline and microRNA (miRNA)-target regulatory interactions. Two lncRNAs with central topological properties in the AFLMN were first obtained. By using bidirectional hierarchical clustering, we identified two modules containing four lncRNAs, which were significantly enriched in many known pathways of AF. To elucidate the ceRNA interactions in certain disease or normal condition, the dysregulated lncRNA-mRNA crosstalks in AF were further analyzed, and six hub lncRNAs were obtained from the network. Furthermore, random walk analysis of the AFLMN suggested that lncRNA RP11-296O14.3 may function importantly in the pathological process of AF. All these eight lncRNAs that were identified from previous steps (RP11-363E7.4, GAS5, RP11-410L14.2, HAGLR, RP11-421L21.3, RP11-111K18.2, HOTAIRM1, and RP11-296O14.3) exhibited a strong diagnostic power for AF. The results of our study provide new insights into the functional roles and regulatory mechanisms of lncRNAs in AF, and facilitate the discovery of novel diagnostic biomarkers or therapeutic targets.

Identification of potentially critical genes in the development of heart failure after ST-segment elevation myocardial infarction (STEMI).

Heart failure (HF) remains a common complication after acute ST-segment elevation myocardial infarction (STEMI). Here, we aim to identify critical genes related to the developed HF in patients with STEMI using bioinformatics analysis. The microarray data of GSE59867, including peripheral blood samples from nine patients with post-infarct HF and eight patients without post-infarct HF, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between HF and non-HF groups were screened by LIMMA package. Functional enrichment analyses of DEGs were conducted, followed by construction of a protein-protein interaction (PPI) network. The dynamic messenger RNA (mRNA) level of the hub genes during the follow-up was analyzed to further elucidate their role in HF development. A total of 58 upregulated and 75 downregulated DEGs were screen out. They were mainly enriched in biological processes about inflammatory response, extracellular matrix organization, response to cAMP, immune response, and positive regulation of cytosolic calcium ion concentration. Pathway analysis revealed that the DEGs were also involved in hematopoietic cell lineage, pathways in cancer, and extracellular matrix-receptor interaction. In the PPI network consisting of 58 nodes and 72 interactions, CXCL8 (degree = 15), THBS1 (degree = 8), FOS (degree = 7), and ITGA2B (degree = 6) were identified as the hub genes. In the comparison of patients with and without post-infarct HF, the mRNA level of these hub genes were all higher within 30 days but reached similar at 6 months after STEMI. In conclusion, CXCL8, THBS1, FOS, and ITGA2B may play important roles in the development of HF after acute STEMI.

Contractile heterogeneity in ventricular myocardium.

The transmural heterogeneity of the contractility in ventricular muscle has not been well-studied. Here, we investigated the calcium transient and sarcomere contraction/relaxation in the endocardial (Endo) and epicardial (Epi) myocytes. Endo and Epi myocytes were isolated from C57/BL6 mice by Langendorff perfusion. Ca2+ transient and sarcomere contraction/relaxation were recorded simultaneously at different stimulation frequencies using a dual excitation fluorescence photomultiplier system. We found that the Endo myocytes have higher baseline diastolic calcium, significantly larger calcium transient and stronger sarcomere shortening than Epi myocytes. However, both the rising and decline phases for calcium transient and sarcomere shortening were slower in Endo than in Epi myocytes. When simulation frequency was increased from 1 to 3 Hz, a greater percent increase in the diastole calcium level, Ca2+ transient and sarcomere shortening amplitude has been observed in the Endo myocytes. Accordingly, the frequency-dependent acceleration in the decay rate of calcium transient and sarcomere relaxation was more profound in the Endo than in Epi myocytes. Western blot analysis showed that CaMKII activity was significantly higher in Epi than in Endo myocardium before stimulation. However, this transmural heterogeneity was reversed by rapid pacing. CaMKII inhibition by KN93 diminished the frequency-dependent alterations of Ca2+ transient and sarcomere contraction. Our results suggest that the contractility of ventricular myocytes is heterogeneous. The Endo-myocardium is the major force generating layer in the heart, both at slow and fast heart rate, and the transmural heterogeneity of CaMKII activation plays an important role in the frequency-dependent alterations.

Repetitive Transient Ischemia-Induced Cardiac Angiogenesis is Mediated by Camkii Activation.

BACKGROUND/AIMS: Coronary angiogenesis is an important protective mechanism in response to myocardial ischemia in coronary artery disease. However, the underlying mechanisms remain largely unclear. Here, we investigated the role of CaMKII activation in ischemia-induced cardiac angiogenesis. METHODS: Repetitive transient ischemia model was established in C57/BL6 mice by daily multiple episodes (3 times/day) of short time (5 min) occlusion of the left anterior descending coronary artery for 7 days. Coronary angiogenesis was detected by immunofluorescent staining. RT-qPCR and Western blot analyses were used to detect the mRNA and protein levels of CaMKII, p-CaMKII and VEGF. Primary cardiac microvascular endothelial cells (CMECs) were isolated to investigate the effects of KN93 on cell proliferation and migration in hypoxic condition. RESULTS: We found that angiogenesis was induced in the ischemic myocardium and suppressed by chronic intraperitoneal injection of CaMKII inhibitor KN93. RT-qPCR and Western blot analyses showed that myocardial ischemia induced an increased expression and autophosphorylation of CaMKII. VEGF expression was increased in the ischemia model but blunted by KN93. Moreover, KN93 suppressed the proliferation and migration of cardiac endothelial cells in hypoxic condition in which the protein expression of CaMKII, p-CaMKII and VEGF was increased. CONCLUSION: CaMKII is an important mediator for the ischemia-induced coronary angiogenesis, in which CaMKII-triggered VEGF expression plays a key role.

Kaempferol Attenuates Cardiac Hypertrophy via Regulation of ASK1/MAPK Signaling Pathway and Oxidative Stress.

Kaempferol has been demonstrated to provide benefits for the treatment of atherosclerosis, coronary heart disease, hyperlipidemia, and diabetes through its antioxidant and anti-inflammatory properties. However, its role in cardiac hypertrophy remains to be elucidated. The aim of our study was to investigate the effects of kaempferol on cardiac hypertrophy and the underlying mechanism. Mice subjected to aorta banding were treated with or without kaempferol (100 mg/kg/d, p. o.) for 6 weeks. Echocardiography was performed to evaluate cardiac function. Mice hearts were collected for pathological observation and molecular mechanism investigation. H9c2 cardiomyocytes were stimulated with or without phenylephrine for in vitro study. Kaempferol significantly attenuated cardiac hypertrophy induced by aorta banding as evidenced by decreased cardiomyocyte areas and interstitial fibrosis, accompanied with improved cardiac functions and decreased apoptosis. The ASK1/MAPK signaling pathways (JNK1/2 and p38) were markedly activated in the aorta banding mouse heart but inhibited by kaempferol treatment. In in vitro experiments, kaempferol also inhibited the activity of ASK1/JNK1/2/p38 signaling pathway and the enlargement of H9c2 cardiomyocytes. Furthermore, our study revealed that kaempferol could protect the mouse heart and H9c2 cells from pathological oxidative stress. Our investigation indicated that treatment with kaempferol protects against cardiac hypertrophy, and its cardioprotection may be partially explained by the inhibition of the ASK1/MAPK signaling pathway and the regulation of oxidative stress.

The Prognostic Value of Peripheral Artery Disease in Heart Failure: Insights from a Meta-analysis.

BACKGROUND: Peripheral artery disease (PAD) is prevalent in individuals with heart failure (HF). We therefore performed a meta-analysis to assess the prognostic impact of PAD in HF patients. METHODS: A systematic search of PubMed and The Cochrane Library was conducted to identify publications from inception to May 2015. We also manually assessed the reference lists of relevant literature for more eligible citations. Only studies reporting the risk of PAD for prognostic endpoints in HF were included in our meta-analysis. RESULTS: The search strategy yielded eight studies comprising a total of 20,968 subjects, of whom 19.4% had a concurrent PAD. All-cause mortality in HF patients with PAD was profoundly higher than in those without this comorbidity (hazard ratio [HR] 1.36, 95% confidence interval [CI] 1.25 to 1.49). Peripheral artery disease was also associated with significant increases in HF hospitalisation and cardiovascular mortality in individuals with HF (HR 1.15, 95% CI 1.01 to 1.32; HR 1.31, 95% CI 1.13 to 1.52, respectively). Subgroup and sensitivity analyses supported the positive relationship between PAD and HF. CONCLUSIONS: Peripheral artery disease is associated with a worse overall prognosis in HF patients, which highlights the need to increase focus on PAD as an important comorbidity in patients with HF.

Transient outward potassium channel: a heart failure mediator.

Transient outward K(+) current (Ito) plays a crucial role in shaping the early phase of repolarization and setting the plateau voltage level of action potential. As a result, it extensively affects membrane current flow in the plateau window. A great body of evidence illustrates a transmural gradient of I to within ventricular wall with much higher density in epicardial than endocardial myocytes, which is important for the physiological ventricular repolarization. In heart failure (HF), this gradient is diminished due to a greater reduction of I to in epicardial myocytes. This attenuates the transmural gradient of early repolarization, facilitating conduction of abnormal impulses originated in the epicardium. In addition, I to reduction prolongs action potential duration and increases intercellular Ca(2+), thus affecting Ca(2+) handling and the excitation-contraction coupling. Furthermore, increased intercellular Ca(2+) could activate CaMKII and calcineurin whose role in cardiac hypertrophy and HF development has been well established. Based on the impact of I to reduction on electrical activity, signal conduction, calcium handling and cardiac function, restoration of I to is likely a potential therapeutic strategy for HF. In this review, we summarize the physiological and pathological role of cardiac I to channel and the potential impact of I to restoration on HF therapy with an emphasis of recent novel findings.

Enrichment of cardiac differentiation by a large starting number of embryonic stem cells in embryoid bodies is mediated by the Wnt11-JNK pathway.

Embryoid bodies (EBs) with large starting numbers of embryonic stem cells (ESCs) have a greater degree of cardiac differentiation than from low numbers of EBs. However, the biological roles of signaling molecules in these effects are not well understood. Here, we show that groups of EBs with different starting numbers of ESCs had differential gene expression patterns for Wnt5a and Wnt11. Wnt11 significantly increased the percentage of beating EBs by up-regulating the expression of the cardiac-specific genes. Wnt5a did not show these effects. Moreover, Wnt11 significantly increased the level of phosphorylated Jun N-terminal kinase. The inhibition of the JNK pathway by SP600125 blocked the effects of Wnt11. Thus, enrichment of cardiac differentiation in groups of EBs with a larger starting number of ESCs is mediated by the Wnt11-JNK pathway.

DEVELOPMENT AND VALIDATION OF A MODEL FOR PREDICTION OF SEPTIC SHOCK IN NEONATES WITH SEPSIS.

ABSTRACT: Purpose: This study aimed to develop and validate a model for prediction of septic shock in neonates with sepsis. Materials and methods: This retrospective study included early-onset septic neonates in the Renmin Hospital of Wuhan University between January 2017 and June 2021. The neonates were divided into the training set and the validation set in a ratio of 7:3 and further categorized into septic shock group and none-shock group according to presence or absence of shock symptoms. Results: A total of 406 septic neonates were enrolled, including 217 in septic shock group. Sex (odds ratio [OR] = 0.092, 95% confidence interval [CI]: 0.012 to 0.683, P = 0.020), C-reactive protein at 6 h (OR = 8.475, 95% CI: 3.154 to 22.774, P < 0.001), serum amyloid A at 6 h (OR = 1.179, 95% CI: 1.094 to 1.269, P < 0.01), white blood cells at 6 h (OR = 0.173, 95% CI: 0.092 to 0.326, P < 0.001), platelets at 6 h (OR = 0.985, 95% CI: 0.975 to 0.995, P < 0.001), and Ca 2+ at 6 h (OR = 1.44 × 10 11 , 95% CI: 2.70 × 10 6 to 7.70 × 10 15 , P < 0.001) were identified as independent risk factors for septic shock and were further included in the nomogram. The areas under the receiver operator characteristic curve were 0.873 and 0.920 in training and validation sets, respectively. Conclusions: A predictive model for early diagnosis of septic shock in neonates was developed and initially validated in this study, allowing for timely intervention.

Stretch current-induced abnormal impulses in CaMKIIδ knockout mouse ventricular myocytes.

BACKGROUND: CaMKII activation is proarrhythmic in heart failure where myocardium is stretched. However, the arrhythmogenic role of CaMKII in stretched ventricle has not been well understood. OBJECTIVE: We tested abnormal impulse inducibility by stretch current in myocytes isolated from CaMKIIδ knockout (KO) mouse left ventricle (LV) where CaMKII activity is reduced by ≈ 62%. METHODS AND RESULTS: Action potentials were recorded by whole-cell patch clamp, and abnormal impulses were induced in LV myocytes by a simulation of stretch-activated channel (SAC) current. SAC activation failed to induce abnormal impulses in wild type (WT) myocytes but steadily produced early after-depolarizations and automaticity in KO myocytes in which an increase in L-type calcium channel (LTCC) current (I(Ca)) and a reduction of sarcoplasmic reticulum Ca(2+) leak and action potential duration (APD) were observed. The abnormal impulses were not suppressed by CaMKII inhibitor AIP whereas a low concentration of nifedipine eliminated abnormal impulses without shortening APD, implicating I(Ca) in promoting stretch-induced abnormal impulses. In addition, APD prolongation by LTCC opener S(-)Bay K 8644 or isoproterenol facilitated abnormal impulse induction in WT ventricular myocytes even in the presence of CaMKII inhibitor AIP, whereas APD prolongation by K(+) channel blocker 4-aminopyridine promoted abnormal impulses in KO myocytes but not in WT myocytes. CONCLUSION: I(Ca) activation plays a central role in stretch-induced abnormal impulses and APD prolongation is arrhythmogenic only when I(Ca) is highly activated. At increased I(Ca) activation, CaMKII inhibition cannot suppress abnormal impulse induction.

Time-dependent regulation of neuregulin-1ß/ErbB/ERK pathways in cardiac differentiation of mouse embryonic stem cells.

Neuregulin-1ß (NRG-1ß)/ErbB signaling plays crucial roles in the cardiac differentiation of mouse embryonic stem cells (ESCs), but its roles and the underlying mechanisms in cardiac differentiation are incompletely understood. This study showed that NRG-1ß significantly increased the percentage of beating embryoid bodies (EBs) and up-regulated the gene expressions of Nkx2.5, GATA4, α-actin, MLC-2v, and ANF in a time-dependent manner, with no effect on the gene expressions of HCN4 and Tbx3. Inhibition of ErbB receptors with AG1478 significantly decreased the percentage of beating EBs; down-regulated the gene expressions of Nkx2.5, GATA4, MLC-2v, ANF, and α-actin; and concomitantly up-regulated the gene expressions of HCN4 and Tbx3 in a time-dependent manner. Moreover, the up-regulation of transcripts for Nkx2.5 and GATA4 by NRG-1ß was blocked by the extracellular signal-related kinases (ERK) 1/2 inhibitor, U0126. However, U0126 could not inhibit the transcript up-regulations of MLC-2v and ANF by NRG-1ß. The protein quantitation results were consistent with those of gene quantitation. Our results suggest that NRG-1ß/ErbB signaling plays critical roles in the cardiac differentiation of mouse ESCs and in the subtype specification of cardiomyocytes in a time-dependent manner. The ERK1/2 pathway may be involved in the early cardiogenesis, but not in the subtype specification of cardiomyocytes.

Effects of the genetic variants of alcohol-metabolizing enzymes on lipid levels in Asian populations: a systematic review and meta-analysis.

CONTEXT: Emerging evidence indicates that variants of alcohol-metabolizing enzymes may influence lipid metabolism. OBJECTIVE: This study aimed to investigate whether the rs671 and rs1229984 variants affect lipid levels in East Asian individuals. DATA SOURCES: PubMed, Foreign Medical Journal Service, Embase, Cochrane Library, Scopus, MEDLINE, Web of Science, Web of Knowledge, Wanfang, and Chinese Biomedical Literature databases were searched until December 31, 2021. DATA EXTRACTION: Meta-analyses of studies that examined the effects of alcohol-metabolizing enzyme variants on lipid levels, as well as the interaction with alcohol intake, were selected. Data extraction was conducted independently by two investigators and confirmed by the third. DATA ANALYSIS: In total, 86 studies (179 640 individuals) were analyzed. The A allele of rs671 (a functional variant in the ALDH2 gene) was linked to higher levels of low-density lipoprotein cholesterol (LDL-C) and lower levels of triglycerides and high-density lipoprotein cholesterol. In contrast, the A allele of the rs1229984 (a functional variant in the ADH2 gene) was associated only with lower levels of LDL-C. The effects of rs671 and rs1229984 on lipid levels were much stronger in Japanese than in Chinese individuals and in males than in females. Regression analysis indicated that the effects of rs671 on lipid levels were independent of alcohol intake in an integrated East Asian population (ie, Japanese, Chinese, and Korean individuals). Intriguingly, alcohol intake had a statistical influence on lipid levels when the sample analyzed was restricted to Japanese individuals or to males. CONCLUSIONS: The rs671 and rs1229984 variants of alcohol-metabolizing enzymes have significant effects on lipid levels and may serve as genetic markers for lipid dyslipidemia in East Asian populations. Circulating lipid levels in Japanese individuals and in males were modulated by the interaction between rs671 and alcohol intake.

CaMKII inhibition in heart failure, beneficial, harmful, or both.

Calmodulin-dependent protein kinase II (CaMKII) has been proposed to be a therapeutic target for heart failure (HF). However, the cardiac effect of chronic CaMKII inhibition in HF has not been well understood. We have tested alterations of Ca(2+) handling, excitation-contraction coupling, and in vivo ß-adrenergic regulation in pressure-overload HF mice with CaMKIIδ knockout (KO). HF was produced in wild-type (WT) and KO mice 1 wk after severe thoracic aortic banding (sTAB) with a continuous left ventricle (LV) dilation and reduction of ejection fraction for up to 3 wk postbanding. Cardiac hypertrophy was similar between WT HF and KO HF mice. However, KO HF mice manifested exacerbation of diastolic function and reduction in cardiac reserve to ß-adrenergic stimulation. Compared with WT HF, L-type calcium channel current (I(Ca)) density in KO HF LV was decreased without changes in I(Ca) activation and inactivation kinetics, whereas I(Ca) recovery from inactivation was accelerated and Ca(2+)-dependent I(Ca) facilitation, a positive staircase blunted in WT HF, was recovered. However, I(Ca) response to isoproterenol was reduced. KO HF myocytes manifested dramatic decrease in sarcoplasmic reticulum (SR) Ca(2+) leak and slowed cytostolic Ca(2+) concentration decline. Sarcomere shortening was increased, but relaxation was slowed. In addition, an increase in myofilament sensitivity to Ca(2+) and the slow skeletal muscle troponin I-to-cardiac troponin I ratio and interstitial fibrosis and a decrease in Na/Ca exchange function and myocyte apoptosis were observed in KO HF LV. CaMKIIδ KO cannot suppress severe pressure-overload-induced HF. Although cellular contractility is improved, it reduces in vivo cardiac reserve to ß-adrenergic regulation and deteriorates diastolic function. Our findings challenge the strategy of CaMKII inhibition in HF.

Alterations of L-type calcium current and cardiac function in CaMKII{delta} knockout mice.

RATIONALE: Recent studies have highlighted important roles of CaMKII in regulating Ca(2+) handling and excitation-contraction coupling. However, the cardiac effect of chronic CaMKII inhibition has not been well understood. OBJECTIVE: We have tested the alterations of L-type calcium current (I(Ca)) and cardiac function in CaMKIIdelta knockout (KO) mouse left ventricle (LV). METHODS AND RESULTS: We used the patch-clamp method to record I(Ca) in ventricular myocytes and found that in KO LV, basal I(Ca) was significantly increased without changing the transmural gradient of I(Ca) distribution. Substitution of Ba(2+) for Ca(2+) showed similar increase in I(Ba). There was no change in the voltage dependence of I(Ca) activation and inactivation. I(Ca) recovery from inactivation, however, was significantly slowed. In KO LV, the Ca(2+)-dependent I(Ca) facilitation (CDF) and I(Ca) response to isoproterenol (ISO) were significantly reduced. However, ISO response was reversed by beta2-adrenergic receptor (AR) inhibition. Western blots showed a decrease in beta1-AR and an increase in Ca(v)1.2, beta2-AR, and Galphai3 protein levels. Ca(2+) transient and sarcomere shortening in KO myocytes were unchanged at 1-Hz but reduced at 3-Hz stimulation. Echocardiography in conscious mice revealed an increased basal contractility in KO mice. However, cardiac reserve to work load and beta-adrenergic stimulation was reduced. Surprisingly, KO mice showed a reduced heart rate in response to work load or beta-adrenergic stimulation. CONCLUSIONS: Our results implicate physiological CaMKII activity in maintaining normal I(Ca), Ca(2+) handling, excitation-contraction coupling, and the in vivo heart function in response to cardiac stress.

Dynamic Kv4.3-CaMKII unit in heart: an intrinsic negative regulator for CaMKII activation.

AIMS: Reduction of transient outward current (I(to)) and excessive activation of Ca(2+)/Calmodulin-dependent kinase II (CaMKII) are general features of ventricular myocytes in heart failure. We hypothesize that alterations of I(to) directly regulate CaMKII activation in cardiomyocytes. METHODS AND RESULTS: A dynamic coupling of I(to) channel subunit Kv4.3 and inactive CaMKII was discovered in cardiomyocytes with the membrane predominant distribution by co-immunoprecipitation and fluorescence resonance energy transfer techniques. CaMKII dissociation from Kv4.3-CaMKII units caused a significant increase in CaMKII autophosphorylation and L-type calcium current (I(Ca)) facilitation. I(Ca) facilitation was blunted by the compartmental Ca²(+) chelator BAPTA but unaffected by bulk Ca²(+) chelator EGTA, implicating membrane-localized CaMKII. Kv4.3 overexpression reduced basal CaMKII autophosphorylation in myocytes and eliminated Ca²(+)-induced CaMKII activation. Kv4.3 blocks CaMKII activation by binding to the calmodulin binding sites, whereas Kv4.3 uncoupling releases these sites and leads to a substantial CaMKII activation. CONCLUSION: Our results uncovered an important mechanism that regulates CaMKII activation in the heart and implicate I(to) channel alteration in pathological CaMKII activation.