Atox1 regulates macrophage polarization in intestinal inflammation via ROS-NLRP3 inflammasome pathway.

BACKGROUND: Inflammation and oxidative stress play an important role in the pathophysiology of inflammatory bowel disease (IBD). This study aimed to explore the effects of copper chaperone Antioxidant-1 (Atox1) on macrophages in a mouse model of intestinal inflammation. METHODS: A mouse model of TNBS-induced colitis was established and verified using the disease activity index. Atox1 conditional knockout mice were applied. The proportion of macrophages in colonic lamina propria mononuclear cells and ROS production were analyzed using flow cytometry. Inflammatory cytokines were measured using ELISA. Expression of macrophage M1/M2 polarization markers, p47phox, NLRP3, and Caspase-1 p20 was measured using quantitative RT-PCR and Western blotting. RESULTS: Atox1 expression was up-regulated in colon tissues of TNBS-induced colitis mice. Macrophages isolated from TNBS-induced colitis mice showed M1 polarization and nuclear translocation of Atox1. Inhibiting copper chaperone activity decreased p47phox, ROS production, and M1 polarization induced by CuCl2 in macrophages. TNBS induced up-regulation of inflammatory cytokines, M1 polarization markers, and p47phox expression in mice, an effect which was preempted by Atox1 knockout. Inflammatory cytokines and expression of M1 polarization markers, p47phox, NLRP3, Caspase-1 p20 were also increased in macrophages isolated from TNBS-induced colitis mice. These changes were alleviated in mice with Atox1 knockout. The effects of Atox1 on macrophage polarization were mediated via the ROS-NLRP3 inflammasome pathway. CONCLUSION: Atox1 plays a pro-inflammatory role, promotes M1 polarization of macrophages, and increases the concentrations of pro-inflammatory cytokines in intestinal tissue by regulating the ROS-NLRP3 inflammasome pathway. Atox1 is a potential therapeutic target in IBD.

Comparison between conventional approach and three-dimensional mapping system in the catheter ablation of accessory pathway associated with coronary sinus diverticulum: A single-center experience.

BACKGROUND: Posteroseptal accessory pathways (APs) associated with coronary sinus (CS) diverticulum present a rare and challenge for ablation. This study aimed to compare the safety and efficacy of conventional approach and three-dimensional (3D) mapping system in the catheter ablation. METHODS AND RESULTS: This was a retrospective study of all patients (from January 2013 to July 2022) who underwent catheter ablation of posteroseptal AP associated with CS diverticula in our center. Patients who underwent catheter ablation using the traditional fluoroscopy method were included in the conventional method group (n = 13). Patients who underwent catheter ablation using the 3D mapping method were included in the 3D mapping group (n = 11). Clinical characteristics, ablation procedure, and outcomes were recorded and analyzed between the two groups. Out of 669 patients with posteroseptal APs, 24 of them (3.6%) were associated with CS diverticula. All patients in both groups successfully completed the electrophysiological study. In the conventional method group, two patients experienced complications (one patient with pericardial effusion and the other patient with femoral arterial hematoma), and two patients had recurrence. However, no patients suffered from complications or recurrence during follow-up. The procedure time and fluoroscopy time in the conventional method group were significantly longer than those in the 3D mapping method group. CONCLUSIONS: The utilization of 3D mapping led to reduced fluoroscopy time, shorter procedure duration, enhanced acute success rates, and decreased incidence of complications.

The effectiveness and safety of temporary transvenous cardiac pacing leads placement into coronary sinus vein in patients with sick sinus syndrome.

BACKGROUND: The temporary pacing lead routinely is placed into right ventricular (RV), which pose a risk of dislocation and cardiac perforation. OBJECTIVE: We aim to evaluate the effectiveness and safety of temporary transvenous cardiac pacing (TTCP) leads placement into the coronary sinus vein (CSV) in patients with sick sinus syndrome (SSS). METHODS: We investigated patients with SSS who underwent TTCP lead placement into the CSV under the guidance of X-ray between January 2013 and May 2023. Patients were randomly divided into two groups: RV group (n = 33) and CSV group (n = 22). The ordinary passive bipolar electrodes were applied in both groups. In RV groups, electrodes were placed into RV. In CSV group, electrodes were placed into CSV. We evaluated the operation duration, fluoroscopic exposure, first-attempt success rate of leads placement, pacing threshold, success rate of leads placement, rate of leads displacement, and complications. RESULTS: Compared with that in RV group, the procedure time, fluoroscopic exposure was significantly prolonged, while the first-attempt success rate of lead placement was obviously increased in CSV group (both p < .05). Compared with that in RV group, the rate of leads displacement is lower in CSV group (both p < .05). There were three patients occurred cardiac perforation in RV group, but no cardiac perforation was reported in CSV group (p > .05). CONCLUSION: TTCP leads placement into the CSV is an effective and safe strategy in patients with SSS. It indicates a high rate of pacing effectiveness with low device replacement and complication rates.

Transient cardiac electrophysiological changes in a rat model of subarachnoid haemorrhage: a brain-heart interaction.

AIMS: Subarachnoid haemorrhage (SAH) is one of the causes of sudden cardiac death (SCD). However, the time course of ventricular arrhythmias and potential mechanisms responsible for this effect after SAH remain unknown. OBJECTIVE: This study aims to investigate the effect of SAH on ventricular electrophysiological changes and its potential mechanisms in long-term phase. METHODS AND RESULTS: We examined the ventricular electrophysiological remodelling and potential mechanisms in a Sprague Dawley rat model of SAH at six time points (baseline, and Days 1, 3, 7, 14 and 28) and explored the potential mechanisms. We measured the ventricular effective refractory period (ERP), ventricular fibrillation threshold (VFT) and left stellate ganglion (LSG) activity at different time points before and after SAH. We also detected neuropeptide Y (NPY) levels in plasma and myocardial tissues by enzyme-linked immunosorbent assay, and quantified NPY 1 receptor (NPY1R) protein and mRNA expression levels by western blotting and quantitative real-time reverse transcription-polymerase chain reaction, respectively. Subarachnoid haemorrhage gradually prolonged QTc intervals, shortened ventricular ERP and reduced VFT during the acute phase, peaking at Day 3. However, no significant changes were observed from Days 14 to 28 compared to Day 0. Subarachnoid haemorrhage gradually increased LSG activity, increased NPY concentrations and up-regulated NPY1R expression in the acute phase of SAH, peaking at Day 3. However, no significant variations were found from Days 14 to 28 compared to Day 0. CONCLUSION: Subarachnoid haemorrhage increases the transient susceptibility of VAs in the acute phase, and the underlying mechanisms for this response included increased sympathetic activity and up-regulated NPY1R expression.

The association between walking pace and hand grip strength with the risk of chronic obstructive pulmonary disease: a bidirectional Mendelian randomization study.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) currently ranks as the third leading cause of mortality worldwide, imposing substantial burdens on societal and individual health. Amongst health research tools, walking pace (WP) and hand grip strength (HGS) are cornerstones, extensively associated with diverse health conditions. However, the intricate interplay between these factors and COPD risk remains ambiguous. This study aims to elucidate the causal association of WP, HGS, with COPD risk through a bidirectional Mendelian randomization (MR) approach. METHODS: Bidirectional MR analysis was performed using Genome-wide association study (GWAS) data of European individuals for WP, HGS, and COPD. Inverse Variance Weighted (IVW) served as the primary MR analysis approach. To supplement the IVW findings, four additional MR methods [MR-Egger, weighted median, maximum likelihood, simple median] were used. To assess heterogeneity and pleiotropy, sensitivity analyses were performed. In addition, multivariate MR (MVMR) analysis was used to assess causality after adjustment for potential confounders. RESULTS: IVW method results show a significant negative association between WP and COPD risk in both initial (genome-wide threshold, odds ratio (OR) = 0.21, 95% confidence interval (CI) 0.09-0.51, P = 5.06 × 10- 4) and secondary (locus-wide threshold, OR = 0.27, 95%CI: 0.18-0.41, P = 4.88 × 10- 10) MR analysis. The reverse MR analysis suggested that COPD also diminishes WP. Additionally, a causal risk reduction for COPD with right HGS (OR = 0.74, 95% CI: 0.58-0.94, P = 1.44 × 10- 2) was only found in secondary MR analysis. The outcomes of the four additional MR methods also suggested similar causal relationships, and sensitivity analyses endorsed their robustness. Lastly, the MVMR analysis demonstrated that the WP's effect on reducing COPD risk persisted independently of potential confounding variables. CONCLUSION: A bidirectional causal relationship exists between typical WP and COPD risk. Conversely, a decrease in right HGS is unidirectionally associated with an increased risk of COPD. The study suggests that WP may serve as a predictive factor for COPD or as a simple evaluative indicator for prognosis.

Apigenin reduces the suppressive effect of exosomes derived from irritable bowel syndrome patients on the autophagy of human colon epithelial cells by promoting ATG14.

BACKGROUND: Inflammatory bowel disease (IBS) is a chronic disorder of the gastrointestinal tract. Exosomes have been involved in various pathological processes including IBS. Apigenin has been reported to suppress inflammatory bowel disease (IBS). However, the regulatory roles of exosomes derived from IBS patients (IBS-exos) on human colon epithelial cells are still unclear. METHODS: Exosomes were collected from IBS patients (IBS-exos) and co-cultured with CACO-2 cells. Apigenin was used to treat IBS-exos-treated CACO-2 cells. By exploring the public data bank, we figured out the regulators control the autophagy of CACO-2 cells. RESULTS: Administration of apigenin dose-dependently abolished the inhibitory effect of IBS-exo on the autophagy of CACO-2 cells. A mechanistic study showed that miR-148b-3p bound to 3'UTR to suppress ATG14 and decrease autophagy. Moreover, results suggested that ATG14 overexpression promoted the autophagy of CACO-2 cells in the presence of miR-148b-3p mimic. CONCLUSION: The current study showed that apigenin dose-dependently abolished the inhibitory effect of IBS-exo on CACO-2 cell autophagy by regulating miR-148b-3p/ATG14 signaling.

Clinical characteristics and the severity of coronary atherosclerosis of different subtypes of bundle-branch block.

BACKGROUND: Right bundle-branch block (RBBB) and left bundle-branch block (LBBB) play a role in the pathogenesis and progression of coronary artery disease (CAD). However, the clinical features and the severity of coronary artery disease associated with different subtypes of bundle-branch block, according to time of new appearance, is not well characterized in patients with no known CAD. METHODS: We retrospectively analyzed data pertaining to consecutive patients with RBBB or LBBB who underwent coronary angiography. The severity of coronary lesions was evaluated using the SYNTAX score. The differential effect of new-onset RBBB, old RBBB, new-onset LBBB, and old LBBB on the severity of CAD and its association with clinical characteristics was quantified. Multivariate logistic regression analysis was performed to evaluate the effect of RBBB and LBBB on the degree of coronary atherosclerosis in patients without known CAD. RESULTS: Out of the 243 patients, 72 patients had old LBBB, 37 had new-onset LBBB, 93 patients had old RBBB, and 41 patients had new-onset RBBB. On univariate analysis, age, systolic blood pressure, diastolic blood pressure, creatinine, serum glucose, and glycosylated hemoglobin level were associated with high SYNTAX score (p < .05 for all). Patients in the new-onset RBBB, old RBBB, new-onset LBBB, and old LBBB groups showed significant differences in baseline characteristics and coronary atherosclerosis (p < .05 for all). However, there were no significant between-group differences with respect to the degree of coronary atherosclerosis as assessed by SYNTAX score. CONCLUSIONS: New-onset RBBB, old RBBB, new-onset LBBB, and old LBBB were not associated with the severity of coronary lesions as assessed by SYNTAX score in patients without known CAD.

Association between adiponectin-to-leptin ratio and heart rate variability in new-onset paroxysmal atrial fibrillation: A retrospective cohort study.

BACKGROUND: The adiponectin-to-leptin (A/L) ratio has been identified as a potential surrogate biomarker for metabolic disorders. However, it remains unknown whether the serum A/L ratio is associated with heart rate variability in paroxysmal atrial fibrillation (AF). METHODS: For this retrospective study, we included consecutive patients who underwent 24-h long-range electrocardiogram examination in our center for paroxysmal AF. The results of echocardiography, heart rate variability tests, and blood tests were also retrieved. Multivariate line regression analysis was performed to evaluate identify factors independently associated with heart rate variability. RESULTS: Among the 85 included patients with paroxysmal AF, the median A/L ratio was 1.71. Univariate analysis indicated that patients with a low A/L ratio (<1.71, n = 42) had a lower high-frequency (HF) power and a higher hs-CRP level, low-frequency (LF) power, and LF/HF ratio than those with a high A/L ratio (≥1.71, n = 43). Multivariate linear regression analysis showed that the serum leptin concentration was independently and positively associated with LF (ß = 0.175, p = .028), while the serum adiponectin concentration was independently and positively associated with HF (ß = 0.321, p = .001). Moreover, the A/L ratio was independently and negatively associated with the LF/HF ratio (ß = -0.276, p = .007). CONCLUSIONS: The A/L ratio was independently and negatively associated with the LF/HF ratio in patients with new-onset paroxysmal AF.

Right-sided Mahaim-mediated tachycardia combined with atypical atrioventricular nodal reentrant tachycardia and left free wall accessory pathway: A case report.

A 37-year-old man was admitted to our hospital with paroxysmal palpitation for half year. A previous electrogram showed a narrow complex tachycardia. Electrophysiologic study (EPS) found a concealed left-sided free wall pathway accessory. In addition, a transseptal approach was used for radiofrequency ablation. After successful ablation, EPS induced a wide complex tachycardia and a narrow complex tachycardia. The wide complex tachycardia was diagnosed as a right-sided Mahaim fiber atriofascicular accessory pathway, and the narrow complex tachycardia was diagnosed as atypical atrioventricular nodal reentrant tachycardia (AVNRT). Then, the right-sided Mahaim fiber atriofascicular accessory pathway and atypical AVNRT were successfully ablated. Herein, we report a rare case of a concealed left-sided accessory pathway combined with a right atriofascicular Mahaim fiber and atypical AVNRT.

Inadvertent malposition of a permanent ventricular lead into the middle cardiac vein was misdiagnosed as lead perforation.

A 54-year-old man had a dual-chamber pacemaker implantation 9 years ago because of sick sinus syndrome at a different facility. The patient did not undergo any evaluation of his pacemaker for a long time with cardiologist. The patient was admitted to another hospital manifesting dyspnea and palpitation with atrial fibrillation for 1 month, and he was diagnosed with ventricular lead perforation. For further treatment, he was referred to our hospital, and an elective replacement indicator (ERI) of the battery state and a malpositioned ventricular lead into the middle cardiac vein were found. Finally, the pacing lead was left in the primary place and the pacemaker was replaced.

Bedside temporary transvenous cardiac pacing lead placement in patients with tricuspid valve surgery without guidance of X-ray: A single-center experience.

BACKGROUND: It is difficult to insert cardiac pacing leads in patient with tricuspid valve surgery (TVS). The aim of this study was to evaluate safety and effectiveness of a novel technique applied for bedside temporary pacemaker placement (TPP) in patients with TVS. METHODS: We investigated patients with TVS who required bedside TPP without X-ray guidance in cardiac intensive care unit between January 2019 and March 2022. They were divided into Novel pre-shaped group (N = 21) and Control group (routine pre-shaped group, N = 26). The ordinary bipolar electrodes were applied in both groups. In Novel pre-shaped group, electrodes were reshaped by a novel technique with three-curve with anterior tip method, while electrodes were shaped by traditional strategy in Control group. We evaluated the operation duration, first-attempt success rate of the lead placement, pacing threshold, success rate of lead placement, the rate of leads displacement, and complications. RESULTS: Compared with that in Control group, the procedure time was significantly shortened and the first-attempt success rate of lead placement was obviously increased in Novel pre-shaped group (both p < 0.05). Although there was a slight reduction in complications in Novel pre-shaped group when compared with that in Control group. However, there were no statistical significance in pacing threshold, the success rate of lead placement, the rate of leads displacement, and complications when compared between two groups. CONCLUSIONS: We propose a novel technique, three-curve with anterior tip method, is a feasible and effective bedside method to insert emergency temporary pacing leads in patients with TVS.

The efficacy and safety of immune checkpoint inhibitor in patients with relapsed small-cell lung cancer: A systematic review and meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: Immune checkpoint inhibitors (ICIs) have been approved for treating small-cell lung cancer (SCLC). However, the efficacy and safety profile of ICIs for relapsed SCLC remains under investigation. In this study, we assessed the efficacy and safety of ICIs in the treatment of relapsed SCLC patients. METHODS: The databases, including Pubmed, Embase, and the Cochrane library, were systematically searched to retrieve potential eligible studies from the establishment of the database to May 2021. The primary outcomes were survival, treatment responses, and safety. Randomized controlled trials and real-world studies that met the inclusion criteria were included. The RevMan 5.4 and R software were used for meta-analysis. RESULTS AND DISCUSSION: A total of eight articles involving 653 patients was included. Meta-analyses results showed that the overall response rate (objective response rate [ORR]) of the ICIs group was 0.12 (95% confidence interval [CI]: 0.07-0.18). The median overall survival was 7.97 (95% CI: 5.94-9.47) months, while the progression-free survival was 1.70 (95% CI: 1.40-2.28) months. Although chemotherapy showed a favourable ORR (odds ratio [OR] = 0.74; 95% CI: 0.39-1.41; p = 0.36) and a significantly better disease control rate (OR = 0.28; 95% CI: 0.11-0.70; p = 0.007), patients treated with ICIs had a reduced risk of mortality (hazard ratio = 0.87; 95% CI: 0.73-1.03; p = 0.10). With regards to adverse events (AEs), the rates of any AEs and ≥grade 3 AEs were 0.56 (95% CI: 0.52-0.60) and 0.13 (95%CI: 0.06-0.20), respectively. WHAT IS NEW AND CONCLUSION: For relapsed SCLC patients, the administration of ICIs resulted in a similar survival outcome and acceptable safety compared with chemotherapy. Further studies are needed to explore potential biomarkers for relapsed SCLC patients who may benefit from immunotherapy.

A real-world study on diagnosis and prognosis of light-chain cardiac amyloidosis in Southern China.

BACKGROUND: Light-chain cardiac amyloidosis (AL-CA) has been highly valued in developed countries, but in developing countries, the recognition and diagnosis of this condition is still limited. There are currently few reports on a large number of Chinese patients with AL-CA. The present study aimed to report real-world clinical characteristics and prognosis of AL-CA in China. METHODS AND RESULTS: Consecutive patients with AL-CA diagnosed at the Second Xiangya Hospital of Central South University between June 2012 and September 2020 were reviewed. A total of 170 patients with AL-CA have been recruited, whose mean ages were 60.81 ± 10.46. 70.59% of the patients were male. They were from eight provinces in southern China, 55.7% were referred patients, and 37.3% had been misdiagnosed previously. 64 (37.6%) patients received chemotherapy. The median survival time for patients with AL-CA was 8.00 months, and survival time for patients who received chemotherapy was 13.00 months, which was significantly longer than that of patients with palliative treatment (13.00 vs 6.00, p = 0.004). CONCLUSIONS: Although clinicians have improved their understanding of AL-CA in recent years, the prognosis of AL-CA is still poor, and the misdiagnosis rate and missed diagnosis rate are still very high in China. It is imperative to improve the recognition and early diagnosis of this condition, which may require multidisciplinary collaboration among cardiologists, hematologists and nephrologists.

Intrinsic brain abnormalities of irritable bowel syndrome with diarrhea: a preliminary resting-state functional magnetic resonance imaging study.

BACKGROUND: The aim of the present study was to explore the brain active characteristics of patients with irritable bowel syndrome with diarrhea (IBS-D) using resting-state functional magnetic resonance imaging technology. METHODS: Thirteen IBS-D patients and fourteen healthy controls (HC) were enrolled. All subjects underwent head MRI examination during resting state. A voxel-based analysis of fractional amplitude of low frequency fluctuation (fALFF) maps between IBS-D and HC was performed using a two-sample t-test. The relationship between the fALFF values in abnormal brain regions and the scores of Symptom Severity Scale (IBS-SSS) were analyzed using Pearson correlation analysis. RESULTS: Compared with HC, IBS-D patients had lower fALFF values in the left medial superior frontal gyrus and higher fALFF values in the left hippocampus and right precuneus. There was a positive correlation between the duration scores of IBS-SSS and fALFF values in the right precuneus. CONCLUSION: The altered fALFF values in the medial superior frontal gyri, left hippocampus and right precuneus revealed changes of intrinsic neuronal activity, further revealing the abnormality of gut-brain axis of IBS-D.

Reduction of Inhospital Mortality of Patient Admissions to Cardiac Intensive Care Units During the COVID-19 Pandemic in Hunan, China.

This study aims to evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on patient admissions to Hunan's cardiac intensive care units (CCUs).We conducted a retrospective, single-center study. Data were collected from patients who were confirmed to have critical cardiovascular disease and admitted to the CCU of the Second Xiangya Hospital of Central South University, Hunan, from January 23 to April 23, 2020. Compared with the same period in 2019, the results show that the number of hospitalization decreased by 19.6%; the inhospital mortality rate of CCU was decreased (28.57% versus 16.67%; odds ratio (OR), 0.50; 95% confidence interval (CI), 0.251-0.996; P = 0.047); hospital stay was decreased (7.97 versus 12.36, P < 0.001); hospital emergency percutaneous coronary intervention (PCI) rate in patients with acute coronary syndromes (ACS) significantly decreased (76.00% versus 39.00%, P < 0.001); among this, the PCI rate of patients with ST-segment elevation myocardial infarction (STEMI) decreased (76.32% versus 55.17%, P = 0.028) as well. In addition, the number of patients transferred from other hospitals significantly decreased (76.79% versus 56.67%, P = 0.002), and the number of patients transferred from other cities also decreased by 10.75%.During the outbreak of the COVID-19 epidemic in Hunan Province, the number of patients admitted to CCU decreased, as well as the mortality rate; fewer patients with severe cardiovascular disease can be transported to better hospitals from remote rural areas. In addition to epidemic prevention and control, experts in China should focus on improved emergency transport medical services to reduce this impact.

Osteoprotegerin promotes intimal hyperplasia and contributes to in-stent restenosis: Role of an αVß3/FAK dependent YAP pathway.

OBJECTIVE: Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are related to in-stent-restenosis (ISR) following percutaneous coronary intervention (PCI). Osteoprotegerin (OPG) has been implicated in various vascular diseases. However, the effects of OPG on ISR and the underlying mechanism remained elusive. We here investigated the association between OPG and ISR, and to demonstrate the role and potential mechanisms of OPG in neointimal hyperplasia. APPROACH AND RESULTS: From 2962 patients who received coronary angiography and follow-up coronary angiography at approximately one year, 291 patients were diagnosed with ISR, and another 291 gender- and age- matched patients without ISR were selected as controls. Serum OPG levels were significantly increased in patients with ISR. Multivariable logistic regression analysis indicated that OPG level was independently associated with the increased risk of ISR. In a mouse femoral artery wire injury model, upregulated OPG was evidenced in vascular tissue after injury. OPG deletion attenuated the vascular injury-induced neointimal hyperplasia and related gene expression in mice. OPG promoted neointimal hyperplasia and human aortic smooth muscle cell (hASMC) proliferation and migration through activation of yes-associated protein (YAP), a major downstream effector of the Hippo signaling pathway, whereas knockdown or inhibition of YAP in hASMCs blunted OPG-induced above effects. Moreover, we found that OPG, as a ligand for integrin αVß3, mediated phosphorylation of focal adhesion kinase (FAK) and actin cytoskeleton reorganization, resulting in YAP dephosphorylation in hASMCs. OPG-dependent YAP and VSMC activation was prevented by treatment with αVß3-blocking antibodies and inhibitors of FAK and actin stress fibers. CONCLUSIONS: Increased serum OPG levels are associated with increased risk of ISR following PCI and OPG could promote neointimal hyperplasia in response to injury through integrin αVß3 mediated FAK and YAP activation, indicating OPG/YAP inhibition might serve as an attractive novel target for the prevention of ISR after PCI.

Rab5a Promotes Cytolethal Distending Toxin B-Induced Cytotoxicity and Inflammation.

The cytolethal distending toxin B subunit (CdtB) induces significant cytotoxicity and inflammation in many cell types that are involved in the pathogenesis of postinfectious irritable bowel syndrome (PI-IBS). However, the underlying mechanisms remain unclear. This study tested the potential role of Rab small GTPase 5a (Rab5a) in the process. We tested mRNA and protein expression of proinflammatory cytokines (interleukin-1ß [IL-1ß] and IL-6) in THP-1 macrophages by quantitative PCR (qPCR) and enzyme-linked immunosorbent assays (ELISAs), respectively. In the primary colonic epithelial cells, Cdt treatment induced a CdtB-Rab5a-cellugyrin association. Rab5a silencing, by target small hairpin RNAs (shRNAs), largely inhibited CdtB-induced cytotoxicity and apoptosis in colon epithelial cells. CRISPR/Cas9-mediated Rab5a knockout also attenuated CdtB-induced colon epithelial cell death. Conversely, forced overexpression of Rab5a intensified CdtB-induced cytotoxicity. In THP-1 human macrophages, Rab5a shRNA or knockout significantly inhibited CdtB-induced mRNA expression and production of proinflammatory cytokines (IL-1ß and IL-6). Rab5a depletion inhibited activation of nuclear factor-κB (NF-κB) and Jun N-terminal protein kinase (JNK) signaling in CdtB-treated THP-1 macrophages. Rab5a appears essential for CdtB-induced cytotoxicity in colonic epithelial cells and proinflammatory responses in THP-1 macrophages.

Uremic Toxin Indoxyl Sulfate Promotes Proinflammatory Macrophage Activation Via the Interplay of OATP2B1 and Dll4-Notch Signaling.

BACKGROUND: Chronic kidney disease (CKD) increases cardiovascular risk. Underlying mechanisms, however, remain obscure. The uremic toxin indoxyl sulfate is an independent cardiovascular risk factor in CKD. We explored the potential impact of indoxyl sulfate on proinflammatory activation of macrophages and its underlying mechanisms. METHODS: We examined in vitro the effects of clinically relevant concentrations of indoxyl sulfate on proinflammatory responses of macrophages and the roles of organic anion transporters and organic anion transporting polypeptides (OATPs). A systems approach, involving unbiased global proteomics, bioinformatics, and network analysis, then explored potential key pathways. To address the role of Delta-like 4 (Dll4) in indoxyl sulfate-induced macrophage activation and atherogenesis in CKD in vivo, we used 5/6 nephrectomy and Dll4 antibody in low-density lipoprotein receptor-deficient (Ldlr-/-) mice. To further determine the relative contribution of OATP2B1 or Dll4 to proinflammatory activation of macrophages and atherogenesis in vivo, we used siRNA delivered by macrophage-targeted lipid nanoparticles in mice. RESULTS: We found that indoxyl sulfate-induced proinflammatory macrophage activation is mediated by its uptake through transporters, including OATP2B1, encoded by the SLCO2B1 gene. The global proteomics identified potential mechanisms, including Notch signaling and the ubiquitin-proteasome pathway, that mediate indoxyl sulfate-triggered proinflammatory macrophage activation. We chose the Notch pathway as an example of key candidates for validation of our target discovery platform and for further mechanistic studies. As predicted computationally, indoxyl sulfate triggered Notch signaling, which was preceded by the rapid induction of Dll4 protein. Dll4 induction may result from inhibition of the ubiquitin-proteasome pathway, via the deubiquitinating enzyme USP5. In mice, macrophage-targeted OATP2B1/Slco2b1 silencing and Dll4 antibody inhibited proinflammatory activation of peritoneal macrophages induced by indoxyl sulfate. In low-density lipoprotein receptor-deficient mice, Dll4 antibody abolished atherosclerotic lesion development accelerated in Ldlr-/- mice. Moreover, coadministration of indoxyl sulfate and OATP2B1/Slco2b1 or Dll4 siRNA encapsulated in macrophage-targeted lipid nanoparticles in Ldlr-/- mice suppressed lesion development. CONCLUSIONS: These results suggest that novel crosstalk between OATP2B1 and Dll4-Notch signaling in macrophages mediates indoxyl sulfate-induced vascular inflammation in CKD.

The Use of Noninvasive Vagal Nerve Stimulation to Inhibit Sympathetically Induced Sinus Node Acceleration: A Potential Therapeutic Approach for Inappropriate Sinus Tachycardia.

BACKGROUND: Hyperactivity of the cardiac sympathetic nervous system may underlie the pathogenesis of inappropriate sinus tachycardia (IST). Studies have proven that cervical vagal stimulation could inhibit stellate ganglion neural activity. SUBJECTS: To investigate whether noninvasive vagal nerve stimulation (NVNS) could inhibit sympathetically induced sinus node acceleration by reducing right stellate ganglion (RSG) neural activity. METHODS: Sixteen anesthetized dogs were randomly divided into NVNS group (with NVNS, n = 8) and control group (with sham NVNS, n = 8). NVNS was delivered to the vagus nerve innervating at the right tragus with a voltage of 80% below the threshold, the minimal voltage to slow the sinus rate or atrioventricular conduction. The maximal sinus rate accelerations induced by high-frequency stimulation (HFS) of RSG and RSG neural activity were measured at baseline and 3 hours after NVNS. At the end, SK2, c-fos, and NGF protein expression in RSG were examined in both groups. RESULTS: Compared to baseline, the maximal sinus node acceleration induced by RSG stimulation and the RSG neural activity were both significantly attenuated after 3 hours of NVNS (P < 0.05 for both). However, these indices did not change significantly in the control group (P > 0.05). SK2 expression in RSG was significantly higher and c-fos and NGF expressions were significantly lower in the NVNS group than those in the control group (P < 0.05). CONCLUSION: Noninvasive vagal nerve stimulation may suppress RSG activity possibly by modulating SK2, c-fos, and NGF expressions in RSG, thus inhibiting sympathetically induced sinus node acceleration.