Unveiling the microbiota-metabolite-myocardium axis: a novel perspective on cardiovascular health.

Introduction: Cardiovascular diseases, including myocardial infarction, remain a leading cause of death globally. Emerging evidence suggests the gut microbiota plays a crucial role in cardiovascular health. This study aims to explore the impact of gut microbiota on myocardial infarction using a mouse model. Methods: The research utilizes a multi-omics approach, including 16S rDNA sequencing and LC-MS-based metabolomics to analyze fecal and serum samples from mice modeled to mimic myocardial infarction. This methodology allows for a comprehensive analysis of microbial populations and their metabolic output. Results: The findings reveal a significant reduction in gut microbiota α-diversity in mice with induced myocardial infarction compared to healthy controls. Notably, there is an increase in populations of Fusobacteria and Clostridia. Metabolomic analysis indicates disruptions in amino acid and energy metabolism, suggesting a metabolic dysregulation linked to myocardial health. Discussion: The study proposes a novel microbiota-metabolite-myocardium axis, where specific microbial metabolites may directly affect heart health. This connection points to the gut microbiota as a potential player in the pathogenesis of myocardial infarction and may open new therapeutic avenues targeting the gut microbiome to combat cardiovascular diseases.

The functional role of circRNA CHRC through miR-431-5p/KLF15 signaling axis in the progression of heart failure.

Pathological myocardial hypertrophy is a common early clinical manifestation of heart failure, with noncoding RNAs exerting regulatory influence. However, the molecular function of circular RNAs (circRNAs) in the progression from cardiac hypertrophy to heart failure remains unclear. To uncover functional circRNAs and identify the core circRNA signaling pathway in heart failure, we construct a global triple network (microRNA, circRNA, and mRNA) based on the competitive endogenous RNA (ceRNA) theory. We observe that cardiac hypertrophy related circRNA (circRNA CHRC), within the ceRNA network, is down-regulated in both transverse aortic constriction (TAC) mice and Ang-II--treated primary mouse cardiomyocytes. Silencing circRNA CHRC increases cross-sectional cell area, atrial natriuretic peptide, and ß-myosin heavy chain levels in primary mouse cardiomyocytes. Further screening reveals that circRNA CHRC targets the miR-431-5p/KLF15 axis implicated in heart failure progression in vivo and in vitro. Immunoprecipitation with anti-Ago2-RNA confirms the interaction between circRNA CHRC and miR-431-5p, while miR-431-5p mimics reverse Klf15 activation caused by circRNA CHRC overexpression. In summary, circRNA CHRC attenuates cardiac hypertrophy via sponging miR-431-5p to maintain the normal level of Klf15 expression.

Concordant and Heterogeneity of Single-Cell Transcriptome in Cardiac Development of Human and Mouse.

Normal heart development is vital for maintaining its function, and the development process is involved in complex interactions between different cell lineages. How mammalian hearts develop differently is still not fully understood. In this study, we identified several major types of cardiac cells, including cardiomyocytes (CMs), fibroblasts (FBs), endothelial cells (ECs), ECs/FBs, epicardial cells (EPs), and immune cells (macrophage/monocyte cluster, MACs/MONOs), based on single-cell transcriptome data from embryonic hearts of both human and mouse. Then, species-shared and species-specific marker genes were determined in the same cell type between the two species, and the genes with consistent and different expression patterns were also selected by constructing the developmental trajectories. Through a comparison of the development stage similarity of CMs, FBs, and ECs/FBs between humans and mice, it is revealed that CMs at e9.5 and e10.5 of mice are most similar to those of humans at 7 W and 9 W, respectively. Mouse FBs at e10.5, e13.5, and e14.5 are correspondingly more like the same human cells at 6, 7, and 9 W. Moreover, the e9.5-ECs/FBs of mice are most similar to that of humans at 10W. These results provide a resource for understudying cardiac cell types and the crucial markers able to trace developmental trajectories among the species, which is beneficial for finding suitable mouse models to detect human cardiac physiology and related diseases.

Blockade of high mobility group box 1 involved in the protective of curcumin on myocardial injury in diabetes in vivo and in vitro.

The aim of this study was to investigate the protective effect of curcumin (Cu) on myocardial injury in diabetic cardiomyopathy in vivo and in vitro. Serum and myocardial glucose, inflammatory cytokines, and cardiac function indexes of type 2 diabetes db/db mice were measured. The mechanism of action was confirmed by immunohistochemistry, immunofluorescence, and western blot experiments. H9C2 cells stimulated by glucose (Glu) were used as cell models in vitro. Cu treatment improved glucose tolerance and lipid profile and reduced the production of inflammatory cytokines. In addition, Cu decreased the serum biochemical indexes. Cu inhibits high mobility group box 1 (HMGB1) signaling pathway in db/db mice. Cu treatment also significantly inhibited pa-induced inflammatory signaling pathway in H9C2 cells. HMGB1 inhibitor or HMGB1 knockdown counteracted the effects of Cu on diabetic cardiomyopathy. The present study showed the protective effects of Cu on myocardial injury via HMGB1 pathway in diabetic cardiomyopathy in vivo and in vitro.

Hypoxia destroys the microstructure of microtubules and causes dysfunction of endothelial cells via the PI3K/Stathmin1 pathway.

BACKGROUND: Endothelial cells (EC) are sensitive to changes in the microenvironment, including hypoxia and ischemia. Disruption of the microtubular network has been reported in cases of ischemia. However, the signaling pathways involved in hypoxia-induced microtubular disruption are unknown. The purpose of this study was to investigate the molecular mechanisms involved in hypoxia-induced microtubular disassembly in human umbilical vein endothelial cells (HUVECs). RESULTS: HUVECs were cultured under normoxic or hypoxic conditions and pretreated with or without colchicine or paclitaxel. The MTT assay, Transwell assay, trans-endothelial permeability assay, and 5-bromo-2'-deoxy-uridine staining were used to test the survival rate, migration, permeability, and proliferation of cells, respectively. Transmission electron microscopy and phalloidin staining were used to observe the microstructure and polymerization of microtubules. The results show that the functions of HUVECs and the microtubular structure were destroyed by hypoxia, but were protected by paclitaxel and a reactive oxygen species (ROS) inhibitor. We further used western blot, a luciferase assay, and co-immunoprecipitation to describe a non-transcription-independent mechanism for PI3K activation-inhibited microtubular stability mediated by Stathmin1, a PI3K interactor that functions in microtubule depolymerization. Finally, we determined that hypoxia and ROS blocked the interaction between PI3K and Stathmin1 to activate disassembly of microtubules. CONCLUSION: Thus, our data demonstrate that hypoxia induced the production of ROS and damaged EC function by destroying the microtubular structure through the PI3K/stathmin1 pathway.

MiR-22 may Suppress Fibrogenesis by Targeting TGFßR I in Cardiac Fibroblasts.

BACKGROUND/AIMS: Cardiac fibrosis after myocardial infarction (MI) has been identified as a key factor in the development of heart failure, but the mechanisms undelying cardiac fibrosis remained unknown. microRNAs (miRNAs) are novel mechanisms leading to fibrotic diseases, including cardiac fibrosis. Previous studies revealed that miR-22 might be a potential target. However, the roles and mechanisms of miR-22 in cardiac fibrosis remained ill defined. The present study thus addressed the impact of miR-22 in cardiac fibrosis. METHODS: After seven days following coronary artery occlusion in mice, tissues used for histology were collected and processed for Masson's Trichrome staining. In addition, cardiac fibroblasts were transfected with mimics and inhibitors of miR-22 using Lipofectamin 2000, and luciferase activity was measured in cell lysates using a luciferase assay kit. Western blotting was used to detect the expression of collagen1, α-SMA and TGFßRI proteins levels, and real time-PCR was employed to measure the Col1α1, Col3α1, miR-22 and TGFßRI mRNA levels. RESULTS: In this study, we found that miR-22 was dynamically downregulated following MI induced by permanent ligation of the left anterior descending coronary artery for 7 days, an effect paralleled by significant collagen deposition. Inhibition of miR-22 with AMO-22 resulted in increased expression of Col1α1, Col3α1 and fibrogenesis in cultured cardiac fibroblasts. Conversely, overexpression of miR-22 in cultured cardiac fibroblasts significantly abrogated angiotensin II-induced collagen formation and fibrogenesis. Furthermore, we found that TGFßRI is a direct target for miR-22, and downregulation of TGFßR may have mediated the antifibrotic effect of miR-22. CONCLUSION: Our data clearly demonstrate that miR-22 acts as a novel negative regulator of angiotensin II-induced cardiac fibrosis by suppressing the expression of TGFßRI in the heart and may represent a new potential therapeutic target for treating cardiac fibrosis.

Taxol prevents myocardial ischemia-reperfusion injury by inducing JNK-mediated HO-1 expression.

CONTEXT: Ischemia/hypoxia and reperfusion impair mitochondria and produce a large amount of reactive oxygen species (ROS), which lead to mitochondrial and brain damage. Furthermore, heme oxygenase-1 (HO-1) as a cytoprotective gene protects cells against ROS-induced cell death in ischemia-reperfusion injury. Induction of HO-1 is involved in cytoprotective effects of taxol. OBJECTIVE: We hypothesize that taxol protects cardiac myocytes possibly by preserving myocardial mitochondrial function and inducing HO-1 expression through the JNK pathway. MATERIALS AND METHODS: In this project, the perfused Langendorff hearts isolated from rats were randomly divided into five groups: control, ischemic, ischemic + taxol (0.1 µM), ischemic + taxol (0.3 µM), and ischemic + taxol (1 µM). Briefly, following a 15 min equilibration period, the control group was subject to normoxic perfusion for 120 min; the ischemia group, normoxic reperfusion for 120 min after 30 min ischemia; the taxol groups, normoxic reperfusion for 120 min after 30-min ischemia with taxol (0.1, 0.3, or 1 µM). The microtubule disruption score, ROS levels, and the activity of mitochondrial electron transport chain complexes I and III were examined by using immunohistochemical methods and free radical detection kits. Western blot assay was employed to study the underlying mechanisms. RESULTS: After Taxol treatment (0.1 µM), the ischemic microtubule disruption score was reduced to 9.8 ± 1.9%. The study revealed that 0.1, 0.3, and 1 µM taxol reduced the level of ROS by 33, 46 and 51%, respectively (p < 0.05). In additional, 0.3 and 1 µM taxol dramatically increased the activity of mitochondrial electron transport chain complex I (99.11 ± 2.59, 103.49 ± 3.89) and mitochondrial electron transport chain complex III (877.82 ± 12.08; 907.42 ± 16.21; 914.73 ± 19.39, *p < 0.05). Additionally, phosphorylation levels of JNK1 were significantly increased in the taxol group. Furthermore, the expression level of HO-1 increased with taxol treatments, which could be inhibited by the specific inhibitor of JNK, SP600125. DISCUSSION AND CONCLUSION: Taxol stabilized microtubules and effectively reduced ROS levels during ischemia. It also preserved the activity of mitochondrial complexes I and III. Interestingly, taxol induced the expression of HO-1 via the JNK pathway in cardiac myocytes.

Optical coherence tomography reveals a non-spasm pseudo-coronary artery stenosis: a case report and review of literature.

We described a case of angiographic stenosis that was highly suitable for stenting and it remained even after repeated intracoronary administration of nitroglycerin. However, optical coherence tomography showed the stenosis disappeared and the artery wall was smooth. It was therefore speculated that this was a just non-spasm pseudo-coronary artery stenosis. We hope that sharing this experience can aid cardiologists to avoid unnecessary implantation of stents.

[Association between 1019C/T polymorphism of Connexin 37 gene and restenosis after coronary stenting].

OBJECTIVE: To assess the association between 1019C/T polymorphism of Connexin 37 (CX37) gene and susceptibility to restenosis after percutaneous coronary intervention (PCI) in ethnic Han Chinese patients from Wuxi. METHODS: Five hundred and thirty-two patients with coronary artery disease (CAD) who had undergone PCI underwent coronary angiography (CAG) in 3 months, and were divided into in stent restenosis (ISR) group (n=67) and no instent restenosis (NISR) group (n=465). Five hundred and one healthy individuals have served as the control group. All cases were genotyped with DNA sequencing. RESULTS: Compared with healthy controls, the frequency of CX37 C allele was higher in CAD patients (57.05% vs. 41.32%, P< 0.01). The frequency of C carries (CC+TC) was 79.32% in CAD patients, against 65.47% in healthy controls (P<0.01). The risk for CAD was significantly increased in carriers of C allele (CC+TC) compared with TT homozygotes (OR=2.03, 95% CI: 1.53-2.80). Stratified analysis has indicated a significant difference in the frequency of C allele carriers between both male and female CAD patients and healthy controls (79.63% vs. 72.45%, P=0.02; 78.00% vs. 51.50%, P< 0.01). For both genders, carriers of C allele had a higher risk for CAD compared with TT homozygotes (males: OR=1.48, 95% CI: 1.06-2.09; females: OR=3.34, 95% CI: 1.90-5.86). Compared with NISR group, the frequency of CX37 C allele and C carries (CC+TC) were significantly higher in ISR group (72.39% vs. 54.84%, P< 0.01; 89.55% vs. 77.85%, P=0.027). Compared with TT homozygotes, the risk for restenosis has significantly increased in carriers of C allele (CC+TC) (OR=2.44, 95% CI: 1.08-5.50). Stratified analysis also suggested that the frequency of C carriers was significantly higher in male ISR group compared with male NISR group (92. 86% vs. 77.66%, P=0.008). The risk for restenosis has increased by nearly four fold in carriers of C allele (CC+TC) compared with TT homozygotes (95% CI: 1.32-10.64). However, for female patients, no significant difference was detected in the ISR risk between carriers of CC+TC type and TT homozygotes (P=0.655). CONCLUSION: The C allele of 1019C/T polymorphism in the CX37 gene is associated with susceptibility to CAD as well as restenosis after coronary stenting in male patients from Wuxi.

Association between C1019T polymorphism of the connexin37 gene and coronary heart disease in patients with in-stent restenosis.

Studies have shown that a C1019T polymorphism of the gene encoding the gap junction protein connexin37 is associated with coronary artery disease (CAD). The aim of the present study was to explore the association between the C1019T polymorphism in the connexin37 gene and CAD patients with in-stent restenosis (ISR). A total of 532 patients who had undergone coronary stenting and coronary angiography at least three months after the procedure were divided according to a clinical diagnosis standard into two groups which were ISR (n=67) and no in-stent restenosis (NISR; n=465) groups. A further 501 healthy individuals were controls. The subjects were genotyped by DNA sequencing. The results demonstrated the following: i) connexin37 gene 1019 sites in the population were distributed by polymorphism into three genetic types (CC, TC and TT types). The distribution frequency of the healthy control, ISR and NISR groups conformed to the Hardy-Weinberg genetic balance rule; ii) in comparison with the healthy controls, the frequency of the connexin37 C allele was higher in the CAD patients (57.05% vs. 41.32%; OR, 1.89; 95% CI, 1.58-2.25; P<0.01). The frequency of the C carriers (CC+TC) was 65.47% in the healthy controls, vs. 79.32% in CAD patients (P<0.01). The CAD risk was significantly increased in the carriers of the C allele (CC+TC) compared with TT homozygotes (OR, 2.03; 95% CI, 1.53-2.80; P<0.01). Stratified analysis demonstrated that a significant difference existed in the frequency of C carriers between the male CAD patients and healthy controls (79.63% vs. 72.45%; OR, 1.48; 95% CI, 1.06-2.09, P=0.02), as well as in the female CAD patients (78.00% vs. 51.50%; OR, 3.34; 95% CI, 1.90-5.86; P<0.01). In the female and male CAD patients, the frequency of the connexin37 C allele was higher than in the healthy controls (male: χ(2)=12.67, P<0.01; female: χ(2)=50.20, P<0.01); iii) compared with the NISR group, the frequencies of the connexin37 C allele and C carriers (CC+TC) were significantly higher in the ISR group (frequency of C allele: 72.39% vs. 54.84%; P<0.01; frequency of C carriers: 89.55% vs. 77.85%; P=0.03). Compared with TT homozygotes, the restenosis risk was significantly increased in the carriers of the C allele (CC+TC; OR, 2.44; 95% CI, 1.08-5.50). Subsequent stratified analysis revealed that the frequency of the C allele was significantly higher in the male ISR group than in the male NISR group (78.57% vs. 52.66%; OR, 3.30; 95% CI, 2.05-5.29; P<0.01). The restenosis risk was ∼four-fold higher in the C carriers (CC+TC) than in the TT homozygotes (OR, 3.74; 95% CI, 1.32-10.64). However in the female population, there was no difference in the ISR risk between the carriers of the C allele (CC+TC) and the TT homozygotes (P=0.70). In summary, the C allele of the connexin37 gene is not only is associated with the susceptibility to CAD, but also associated with restenosis following coronary stenting in the population studied herein, particularly the male population.

Effect of rosuvastatin on ROCK activity, endothelial function, and inflammation in Asian patients with atherosclerosis.

BACKGROUND: HMG-CoA reductase inhibitors (statins) inhibit cholesterol biosynthesis, and also decrease the formation of isoprenoid intermediates required for the activation of Rho kinase (ROCK) pathway. ROCK pathway plays pivotal roles in cardiovascular diseases including arteriosclerosis. It has been implicated that inhibition of ROCK can reverse vascular dysfunction in humans with atherosclerosis. However, it is not clear whether statins, at doses used to lower cholesterol levels, inhibit ROCK activity in humans with atherosclerosis. METHODS: We treated 40 subjects with stable atherosclerosis with rosuvastatin 10 mg/day, or rosuvastatin 40 mg/day for 28 days in a randomized, double-blinded study. We assessed the change in the lipid levels, C-reactive protein (CRP), ROCK activity, and flow-mediated dilation (FMD) of the brachial artery before and after statins therapy. RESULTS: Treatment with rosuvastatin 10 mg and 40 mg significantly reduced LDL cholesterol by 43.2% to 55.9% and increased FMD by 29.3% to 42.5% (p<0.05 for both compared with baselines). Both doses inhibited ROCK activity (p<0.05), and the extent of inhibition was greater with rosuvastatin 40 mg compared with 10 mg (p<0.05). Only rosuvastatin 40 mg significantly reduced hsCRP (p<0.05).There was no correlation between changes in ROCK activity and changes in low-density lipoprotein cholesterol (r=0.37, p>0.05 vs. r=0.41, p>0.05) among patients randomized to rosuvastatin 10 mg group or 40 mg group. There was a correlation between ROCK inhibition and change in FMD among patients with rosuvastatin 10 mg therapy (r=0.43, p<0.05), and 40 mg therapy (r=0.54, p<0.05). Correlation was found between changes in ROCK inhibition and changes in CRP in rosuvastatin 40 mg/day group (r=0.47, p<0.05). CONCLUSION: These results demonstrate that high dose rosuvastatin exerts greater effects on LDL-C, ROCK activity, and CRP than low dose rosuvastatin. These findings provide clinical evidence that statins are effective in improving endothelium dysfunction by a cholesterol-independent mechanism in patients with atherosclerosis.

Taxol, a microtubule stabilizer, prevents ischemic ventricular arrhythmias in rats.

Microtubule integrity is important in cardio-protection, and microtubule disruption has been implicated in the response to ischemia in cardiac myocytes. However, the effects of Taxol, a common microtubule stabilizer, are still unknown in ischemic ventricular arrhythmias. The arrhythmia model was established in isolated rat hearts by regional ischemia, and myocardial infarction model by ischemia/reperfusion. Microtubule structure was immunohistochemically measured. The potential mechanisms were studied by measuring reactive oxygen species (ROS), activities of oxidative enzymes, intracellular calcium concentration ([Ca(2+) ](i) ) and Ca(2+) transients by using fluorometric determination, spectrophotometric assays and Fura-2-AM and Fluo-3-AM, respectively. The expression and activity of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) was also examined using real-time polymerase chain reaction, Western blot and pyruvate/Nicotinamide adenine dinucleotide-coupled reaction. Our data showed that Taxol (0.1, 0.3 and 1 µM) effectively reduced the number of ventricular premature beats and the incidence and duration of ventricular tachycardia. The infarct size was also significantly reduced by Taxol (1 µM). At the same time, Taxol preserved the microtubule structure, increased the activity of mitochondrial electron transport chain complexes I and III, reduced ROS levels, decreased the rise in [Ca(2+)](i) and preserved the amplitude and decay times of Ca(2+) transients during ischemia. In addition, SERCA2a activity was preserved by Taxol during ischemia. In summary, Taxol prevents ischemic ventricular arrhythmias likely through ameliorating abnormal calcium homeostasis and decreasing the level of ROS. This study presents evidence that Taxol may be a potential novel therapy for ischemic ventricular arrhythmias.