Microorganisms resided in human body play a vital role in metabolism, immune defense, nutrition absorption, cancer control and protection against pathogen colonization. The changes of microbial communities can cause human diseases. Based on the known microbe-disease association, we presented a novel computational model employing Random Walking with Restart optimized by Particle Swarm Optimization (PSO) on the heterogeneous interlinked network of Human Microbe-Disease Associations (PRWHMDA) (see Figure 1). Based on the known human microbe-disease associations, we constructed the heterogeneous interlinked network with Cosine similarity. The extended random walk with restart (RWR) method was derived to get the potential microbe-disease associations. PSO was utilized to get the optimal parameters of RWR. To evaluate the prediction effectiveness, we performed leave one out cross validation (LOOCV) and 5-fold cross validation (CV), which got the AUC (The area under ROC curve) of 0.915 (LOOCV) and the average AUCs of 0.8875 ± 0.0046 (5-fold CV). Moreover, we carried out three case studies of asthma, inflammatory bowel disease (IBD) and type 1 diabetes (T1D) for the further evaluation. The result showed that 10, 10 and 9 of top-10 predicted microbes were verified by previously published experimental results, respectively. It is anticipated that PRWHMDA can be effective to identify the disease-related microbes and maybe helpful to disclose the relationship between microorganisms and their human host.

Objective: Atrial remodeling is involved in atrial fibrillation (AF), and atrial fibrosis is an important marker of atrial remodeling. On the basis of our previous animal studies of the mitogen-activated protein kinases (MAPKs)/transforming growth factor β1 (TGF-β1)/tumor necrosis factor pathway in atrial fibrosis, we undertook investigation of this signaling pathway in atrial fibrosis of patients with chronic AF (CAF) and rheumatic mitral valve disease. Methods: Fifty-six rheumatic mitral valve disease patients were divided into CAF (course of AF >12 months) and sinus rhythm (SR) groups. Left atrial appendage tissue was collected during heart surgery, and pathological examination was done to evaluate atrial fibrosis. Protein and mRNA expression of TGF-β1, TRAF6 and connective tissue growth factor (CTGF) and protein expression of phosphorylated MAPKs and TGF-β-activated kinase 1 (TAK1) were measured. Results: Histological examination revealed that the severity of atrial fibrosis in CAF patients was significantly higher, mRNA and protein expression of TGF-β1, TRAF6 and CTGF in CAF were significantly increased, and the protein expression of phosphorylated MAPKs and TAK1 was significantly increased in CAF compared to SR patients. Conclusion: The MAPKs/TGF-β1/TRAF6 signaling pathway is involved in atrial fibrosis of CAF patients, and TRAF6 may become a new target for the treatment of atrial fibrosis.

Objectives: Eplerenone (EPL), an antagonist of the mineralocorticoid receptor, is beneficial for atrial fibrillation and atrial fibrosis. However, the underlying mechanism remains less well known. We aimed to investigate the effect of EPL on atrial fibrosis using a mouse with selective atrial fibrosis and to explore the underlying mechanisms. Methods: EPL-treated MHC-TGFcys³³ser transgenic mice that have selective atrial fibrosis (Tx+EPL mice), as well as control mice, were used for in vivo studies including histological analyses, Western blotting, and qRT-PCR studies. TGF-β₁-stimulated atrial fibroblasts were treated with EPL or vehicle for the in vitro studies including Western blotting and qRT-PCR studies. In addition, Smad7 siRNA was used to knock down Smad7. Results: EPL inhibited atrial fibrosis in the Tx mice. In addition, EPL suppressed the expression of fibrosis-related molecules induced by TGF-β₁ in vivo and in vitro. This occurred in concert with a downregulation of Smad7 protein expression and an upregulation of p-Smad2/3 protein expression. In addition, knockdown of Smad7 by siRNA abolished the protective roles of EPL. Conclusions: EPL inhibited atrial fibrosis in Tx mice. The underlying mechanism may involve increased protein expression of Smad7, which enhances the inhibitory feedback regulation of TGF-β₁/Smad signaling.

BackgroundActivin receptor‐like kinase 4 (ALK4) is highly expressed in mammal heart. Atrial fibrillation (AF) is closely related to ventricular pressure overload. Because pressure overload increases atrial pressure and leads to atrial remodeling, it would be informative to know whether ALK4 exerts potential effects on atrial remodeling and AF vulnerability in a pressure‐overload model.Methods and ResultsWild‐type littermates and ALK4+/− mice were subjected to abdominal aortic constriction or a sham operation. After 4 or 8 weeks, echocardiographic and hemodynamic measurements were performed, and inducibility of AF was tested. The hearts were divided into atria and ventricles and then were fixed in formalin for staining, or they were weighted and snap‐frozen for quantitative real‐time polymerase chain reaction and Western blot analysis. Compared with wild‐type littermates, ALK4+/− mice demonstrated a similar extent of atrial hypertrophy but significantly suppressed atrial fibrosis at 8 weeks post–abdominal aortic constriction. ALK4 haplodeficiency partially blocked abdominal aortic constriction–induced upregulation of monocyte chemotactic protein 1 and interleukin‐6, and the increased chemotaxin of macrophages. ALK4 haplodeficiency also blunted a reduction of connexin 40 and redistribution of connexin 43 from the intercalated disk to the lateral membranes, thereby improving localized conduction abnormalities. Meanwhile, ALK4 haplodeficiency inhibited abdominal aortic constriction–induced decreased IN a, IC a‐L and IK 1 densities as well as the accompanying action potential duration shortening. Mechanistically, ALK4 haploinsufficiency resulted in the suppression of Smad2/3 activity in this model.ConclusionsOur results demonstrate that ALK4 haplodeficiency ameliorates atrial remodeling and vulnerability to AF in a pressure‐overload model through inactivation of the Smad2/3 pathway, suggesting that ALK4 might be a potential therapeutic target in combating pressure overload–induced AF.

No abstract

ObjectivesTo explore the relationship between the MAPKs/TGF-β1/TRAF6 signaling pathway and atrial fibrosis in patients with rheumatic heart disease (RHD) and its role in atrial fibrillation (AF) after cardiac surgery on the basis of our previous animal study of the MAPKs/TGF-β1/TRAF6 signaling pathway in atrial fibrosis.MethodsA total of 57 patients with RHD without a history of AF consented to left atrial biopsy. Histopathology quantified the percentage of fibrosis, and real-time PCR and western blot assessed the mRNA and protein expression of TGF-β1, TRAF6, and connective tissue growth factor (CTGF), respectively. Western blot was also used to measure the protein expression of phosphorylated MAPKs and TGF-β-activated kinase 1 (TAK1). Serum angiotensin II (Ang II) levels were assayed using enzyme-linked immunosorbent assay (ELISA).ResultsEighteen patients developed AF, whereas 39 remained in sinus rhythm (SR). The severity of atrial fibrosis was significantly higher in patients who developed AF versus those who remained in SR; the mRNA and protein expression of TGF-β1, TRAF6 and CTGF were significantly higher in patients with AF. The protein expression of phosphorylated MAPKs and TAK1 was significantly increased in patients who developed AF compared with the patients who remained in SR. Serum Ang II levels were significantly higher in patients who developed AF versus those who remained in SR.ConclusionThe MAPKs/TGF-β1/TRAF6 signaling pathway is involved in atrial fibrosis in patients with RHD, which results in the occurrence of AF after cardiac surgery.

BackgroundWeight-adjusted waist circumference index (WWI) is a novel index positively associated with excessive fat accumulation. The current study aims to evaluate the association between WWI and the prevalent heart failure (HF), and to assess the value of WWI to improve the detection of HF in the general population.MethodsA total of 25,509 subjects from National Health and Nutrition Examination Survey 1999–2018 were included into our study. WWI was calculated as WC (cm) divided by the square root of weight (kg). HF was identified according to the subjects’ reports.ResultsThe prevalence of reported HF was 2.96%. With adjustment of demographic, anthropometric, laboratory, and medical history data, one SD increment of WWI could cast an additional 19.5% risk for prevalent HF. After separating WWI into quartiles, the fourth quartile had a 1.670 times risk of prevalent HF compared to the first quartile. Furthermore, smooth curve fitting suggested that the association was linear in the entire range of WWI. Moreover, the association was robust to subgroups of age, sex, race, obesity, hypertension, and diabetes. Additionally, ROC analysis revealed a significant improvement for the detection of prevalent HF from WWI (0.890 vs. 0.894, P < 0.001); And continuous net reclassification index (0.225, P < 0.001) and integrated discrimination index (0.004, P < 0.001) also supported the improvement from WWI.ConclusionOur data demonstrated a significant, linear, and robust association between WWI, a simple surrogate for fat mass accumulation, and the risk for prevalent HF in a representative population. Moreover, our results also suggested the potential value of WWI to refine the detection of prevalent HF in the general population.

Aims The aim of this study was to determine whether driver ablation effectively treats persistent atrial fibrillation (AF) in obese patients. Methods and results We randomly assigned 124 persistent AF obese patients to two groups, one undergoing conventional ablation (n = 62) and the other undergoing driver ablation (n = 62). Sixty-two non-obese patients with persistent AF undergoing driver ablation served as matched controls. Bipolar electrogram dispersion was analysed for driver mapping. Epicardial adipose tissue (EAT) volume was measured using cardiac computed tomography. Obese patients had a higher proportion of driver regions in the posterior wall (56.5% vs. 32.3%, P = 0.007). Driver complexity, measured as the average number and area of driver regions, was higher in the obese group than in the non-obese group (3.5 ± 1.0 vs. 2.9 ± 0.9, P < 0.001; 15.5% ± 4.2% vs. 9.8 ± 2.6%, P < 0.001, respectively). Left atrial EAT volume correlated better with the proportion of area of driver regions than did body mass index (BMI) and total EAT (BMI: r2 = 0.250, P < 0.001; total EAT: r2 = 0.379, P < 0.001; and left atrial EAT: r2 = 0.439, P < 0.001). The rate of AF termination was significantly higher in the driver ablation group than in the conventional ablation group (82.9% vs. 22.8%, P < 0.001). During the follow-up period of 16.9 ± 6.5 months, patients in the driver ablation group had significantly better AF-free survival (91.91% vs. 79.0%, log rank test, P = 0.026) and AF/atrial tachycardia-free survival (83.9% vs. 64.5%, log rank test, P = 0.011) than did patients in the conventional ablation group. Conclusion Obesity is associated with increased driver complexity. Driver ablation improves long-term outcomes in obese patients with persistent AF.