Orphan Nuclear Receptor NR4A3 Promotes Vascular Calcification via Histone Lactylation.

BACKGROUND: Medial arterial calcification is a chronic systemic vascular disorder distinct from atherosclerosis and is commonly observed in patients with chronic kidney disease, diabetes, and aging individuals. We previously showed that NR4A3 (nuclear receptor subfamily 4 group A member 3), an orphan nuclear receptor, is a key regulator in apo (apolipoprotein) A-IV-induced atherosclerosis progression; however, its role in vascular calcification is poorly understood. METHODS: We generated NR4A3-/- mice and 2 different types of medial arterial calcification models to investigate the biological roles of NR4A3 in vascular calcification. RNA-seq was performed to determine the transcriptional profile of NR4A3-/- vascular smooth muscle cells under ß-glycerophosphate treatment. We integrated CUT&Tag analysis and RNA-seq data to further investigate the gene regulatory mechanisms of NR4A3 in arterial calcification and target genes regulated by histone lactylation. RESULTS: NR4A3 expression was upregulated in calcified aortic tissues from chronic kidney disease mice, 1,25(OH)2VitD3 overload-induced mice, and human calcified aorta. NR4A3 deficiency preserved the vascular smooth muscle cell contractile phenotype, inhibited osteoblast differentiation-related gene expression, and reduced calcium deposition in the vasculature. Further, NR4A3 deficiency lowered the glycolytic rate and lactate production during the calcification process and decreased histone lactylation. Mechanistic studies further showed that NR4A3 enhanced glycolysis activity by directly binding to the promoter regions of the 2 glycolysis genes ALDOA and PFKL and driving their transcriptional initiation. Furthermore, histone lactylation promoted medial calcification both in vivo and in vitro. NR4A3 deficiency inhibited the transcription activation and expression of Phospho1 (phosphatase orphan 1). Consistently, pharmacological inhibition of Phospho1-attenuated calcium deposition in NR4A3-overexpressed vascular smooth muscle cells, whereas overexpression of Phospho1 reversed the anticalcific effect of NR4A3 deficiency in vascular smooth muscle cells. CONCLUSIONS: Taken together, our findings reveal that NR4A3-mediated histone lactylation is a novel metabolome-epigenome signaling cascade mechanism that participates in the pathogenesis of medial arterial calcification.

Establishment and application of a new 4/6 infarct nephrectomy rat model for moderate chronic kidney disease.

PURPOSE: To develop a new 4/6 infarct nephrectomy (INx) model rat mimicking moderate chronic kidney disease (CKD) and to evaluate its application. METHODS: We modified the conventional 5/6 INx rat model to create the 4/6 INx model by ligating the renal artery branch to induce infarction of one-third of the left kidney after right kidney removal and compared biochemically and histologically both models. To demonstrate the application of the 4/6 INx model, the effects of a supplementary compound containing calcium carbonate, chitosan, palm shell activated charcoal etc., that is effective for both CKD and its complications, were compared between both models. RESULTS: Impairment of renal function in the 4/6 INx group was significantly more moderate than in the 5/6 INx group (P < 0.05). The 4/6 INx group showed less histological damage in kidney than in the 5/6 INx group. The supplementary compound did not improve CKD in the 5/6 INx group, but ameliorated elevation of blood urea nitrogen in the 4/6 INx group. CONCLUSIONS: We developed the 4/6 INx model, which is more moderate than the conventional 5/6 INx model. This model could potentially demonstrate the effectiveness of drugs and supplements intended to prevent CKD and its progression.

Protective Effects of Hydrogen Gas Inhalation for Hindlimb Ischaemia-Reperfusion Injury in a Mouse Model.

OBJECTIVE: Ischaemia-reperfusion (I/R) injury is a severe post-operative complication that triggers an inflammatory response and causes severe damage. Hydrogen gas has anti-oxidant and anti-apoptotic properties and has been shown to be safe in humans. The study aimed to investigate whether hydrogen gas protects against skeletal muscle I/R injury. METHODS: Experimental basic research using mice. A total of 160 eight to 10 week old albino laboratory bred strain of house mice (25.8 ± 0.68 g) were used in this study. The mice were cable tied to the hindlimb under anaesthesia and then placed in an anaesthesia box filled with air and 2% isoflurane (control group); 80 mice were additionally subjected to 1.3% hydrogen gas in this mix (hydrogen group). After two hours, the cable ties were removed to initiate reperfusion, and hydrogen inhalation lasted for six hours in the hydrogen group. After six hours, the mice were taken out of the box and kept in cages under standard conditions until time for observation at 16 different time points after reperfusion: zero, two, four, six, eight, and 10 hours and one, two, three, four, five, six, seven, 14, 21, and 28 days. Five mice were sacrificed using excess anaesthesia at each time point, and the bilateral hindlimb tissues were harvested. The inflammatory effects of the I/R injury were assessed by evaluating serum interleukin-6 concentrations using enzyme linked immunosorbent assay, as well as histological and immunohistochemical analyses. Untreated mice with I/R injury were used as controls. RESULTS: Hydrogen gas showed protective effects associated with a reduction in inflammatory cell infiltration (neutrophils, macrophages, and lymphocytes), a reduced area of damaged muscle, maintenance of normal muscle cells, and replacement of damaged muscle cells with neoplastic myocytes. CONCLUSION: Inhalation of hydrogen gas had a protective effect against hindlimb I/R injury in mice, in part by reducing inflammatory cell infiltration and in part by preserving normal muscle cells.

Anaerobic threshold using sweat lactate sensor under hypoxia.

We aimed to investigate the reliability and validity of sweat lactate threshold (sLT) measurement based on the real-time monitoring of the transition in sweat lactate levels (sLA) under hypoxic exercise. In this cross-sectional study, 20 healthy participants who underwent exercise tests using respiratory gas analysis under hypoxia (fraction of inspired oxygen [FiO2], 15.4 ± 0.8%) in addition to normoxia (FiO2, 20.9%) were included; we simultaneously monitored sLA transition using a wearable lactate sensor. The initial significant elevation in sLA over the baseline was defined as sLT. Under hypoxia, real-time dynamic changes in sLA were successfully visualized, including a rapid, continual rise until volitionary exhaustion and a progressive reduction in the recovery phase. High intra- and inter-evaluator reliability was demonstrated for sLT's repeat determinations (0.782 [0.607-0.898] and 0.933 [0.841-0.973]) as intraclass correlation coefficients [95% confidence interval]. sLT correlated with ventilatory threshold (VT) (r = 0.70, p < 0.01). A strong agreement was found in the Bland-Altman plot (mean difference/mean average time: - 15.5/550.8 s) under hypoxia. Our wearable device enabled continuous and real-time lactate assessment in sweat under hypoxic conditions in healthy participants with high reliability and validity, providing additional information to detect anaerobic thresholds in hypoxic conditions.

MRP1-Dependent Extracellular Release of Glutathione Induces Cardiomyocyte Ferroptosis After Ischemia-Reperfusion.

BACKGROUND: The membrane components of cardiomyocytes are rich in polyunsaturated fatty acids, which are easily oxidized. Thus, an efficient glutathione-based lipid redox system is essential for maintaining cellular functions. However, the relationship between disruption of the redox system during ischemia-reperfusion (IR), oxidized lipid production, and consequent cell death (ferroptosis) remains unclear. We investigated the mechanisms underlying the disruption of the glutathione-mediated reduction system related to ferroptosis during IR and developed intervention strategies to suppress ferroptosis. METHODS: In vivo fluctuations of both intra- and extracellular metabolite levels during IR were explored via microdialysis and tissue metabolome analysis. Oxidized phosphatidylcholines were assessed using liquid chromatography high-resolution mass spectrometry. The areas at risk following IR were assessed using triphenyl-tetrazolium chloride/Evans blue stain. RESULTS: Metabolomic analysis combined with microdialysis revealed a significant release of glutathione from the ischemic region into extracellular spaces during ischemia and after reperfusion. The release of glutathione into extracellular spaces and a concomitant decrease in intracellular glutathione concentrations were also observed during anoxia-reperfusion in an in vitro cardiomyocyte model. This extracellular glutathione release was prevented by chemical inhibition or genetic suppression of glutathione transporters, mainly MRP1 (multidrug resistance protein 1). Treatment with MRP1 inhibitor reduced the intracellular reactive oxygen species levels and lipid peroxidation, thereby inhibiting cell death. Subsequent in vivo evaluation of endogenously oxidized phospholipids following IR demonstrated the involvement of ferroptosis, as levels of multiple oxidized phosphatidylcholines were significantly elevated in the ischemic region 12 hours after reperfusion. Inhibition of the MRP1 transporter also alleviated intracellular glutathione depletion in vivo and significantly reduced the generation of oxidized phosphatidylcholines. Administration of MRP1 inhibitors significantly attenuated infarct size after IR injury. CONCLUSIONS: Glutathione was released continuously during IR, primarily in an MRP1-dependent manner, and induced ferroptosis. Suppression of glutathione release attenuated ferroptosis and reduced myocardial infarct size following IR.

Deep learning-based model detects atrial septal defects from electrocardiography: a cross-sectional multicenter hospital-based study.

Background: Atrial septal defect (ASD) increases the risk of adverse cardiovascular outcomes. Despite the potential for risk mitigation through minimally invasive percutaneous closure, ASD remains underdiagnosed due to subtle symptoms and examination findings. To bridge this diagnostic gap, we propose a novel screening strategy aimed at early detection and enhanced diagnosis through the implementation of a convolutional neural network (CNN) to identify ASD from 12-lead electrocardiography (ECG). Methods: ECGs were collected from patients with at least one recorded echocardiogram at 3 hospitals from 2 continents (Keio University Hospital from July 2011 to December 2020, Brigham and Women's Hospital from January 2015 to December 2020, and Dokkyo Medical University Saitama Medical Center from January 2010 and December 2021). ECGs from patients with a diagnosis of ASD were labeled as positive cases while the remainder were labeled as negative. ECGs after the closure of ASD were excluded. After randomly splitting the ECGs into 3 datasets (50% derivation, 20% validation, and 30% test) with no patient overlap, a CNN-based model was trained using the derivation datasets from 2 hospitals and was tested on held-out datasets along with an external validation on the 3rd hospital. All eligible ECGs were used for derivation and validation whereas the earliest ECG for each patient was used for the test and external validation. The discrimination of ASD was assessed by the area under the receiver operating characteristic curve (AUROC). Multiple subgroups were examined to identify any heterogeneity. Findings: A total of 671,201 ECGs from 80,947 patients were collected from the 3 institutions. The AUROC for detecting ASD was 0.85-0.90 across the 3 hospitals. The subgroup analysis showed excellent performance across various characteristics Screening simulation using the model greatly increased sensitivity from 80.6% to 93.7% at specificity 33.6% when compared to using overt ECG abnormalities. Interpretation: A CNN-based model using 12-lead ECG successfully identified the presence of ASD with excellent generalizability across institutions from 2 separate continents. Funding: This work was supported by research grants from JST (JPMJPF2101), JSR corporation, Taiju Life Social Welfare Foundation, Kondou Kinen Medical Foundation, Research fund of Mitsukoshi health and welfare foundation, Tokai University School of Medicine Project Research and Internal Medicine Project Research, Secom Science and Technology Foundation, and Grants from AMED (JP23hma922012 and JP23ym0126813). This work was partially supported by One Brave Idea, co-funded by the American Heart Association and Verily with significant support from AstraZeneca and pillar support from Quest Diagnostics.

Genetic Testing Enables the Diagnosis of Familial Hypercholesterolemia Underdiagnosed by Clinical Criteria: Analysis of Japanese Early-Onset Coronary Artery Disease Patients.

Definitive diagnosis of familial hypercholesterolemia (FH) is paramount for the risk management of patients and their relatives. The present study aimed to investigate the frequency of gene variants contributing to low-density lipoprotein cholesterol (LDL-C) metabolism and their clinical relevance in patients with early-onset coronary artery disease (EOCAD). Among 63 consecutive patients with EOCAD (men <55 years or women <65 years) who underwent percutaneous coronary intervention (PCI) from 2013 to 2019 at Keio University Hospital, 52 consented to participate in this retrospective study. Targeted sequencing of LDLR, PCSK9, APOB, and LDLRAP1 was performed. Of the 52 patients enrolled (42 men; mean age: 50 ± 6 years), one (LDLR, c.1221_1222delCGinsT) harbored a pathogenic mutation, and one (APOB, c.10591A>G) harbored variants of uncertain significance. Both the patients harboring the variants were male, showing no history of diabetes mellitus or chronic kidney disease, no family history of EOCAD, and no physical findings of FH (i.e., tendon xanthomas or Achilles tendon thickening). Patients harboring the LDLR variant had three-vessel disease, were on a statin prescription at baseline, and had stable LDL-C levels; however, the case showed a poor response to the intensification of medication after PCI. Approximately 3.8% of patients with EOCAD harbored variants of gene related to LDL-C metabolism; there were no notable indicators in the patients' background or clinical course to diagnose FH. Given the difficulty in diagnosing FH based on clinical manifestations and family history, genetic testing could enable the identification of hidden risk factors and provide early warnings to their relatives.

Complexity of Inflammation in the Trajectory of Vascular Disease: Interleukin 6 and Beyond.

Takayasu's arteritis, first described by Dr. Mikito Takayasu in 1908, is a systemic vasculitis that mostly affects the aorta and its major branches. Although the etiology of the disease is yet unknown, genetic and environmental factors may both play a role. One hundred years after the discovery of Takayasu's arteritis, inflammation is finally widely recognized as a fundamental condition common to all vascular diseases, and clinical trials have proven the efficacy of molecularly targeted drugs that block each step of the NLRP3 inflammasome/interleukin (IL)-1ß/IL-6 cascade in patients with atherosclerotic vascular disease and elevated C-reactive protein (CRP). Recent advances have also been made in the treatment of Takayasu's arteritis. The randomized controlled trials and subsequent open-label and post-marketing surveillance studies in Japan have demonstrated that tocilizumab, an anti-IL-6 receptor antibody, is effective in the treatment of Takayasu's arteritis and prevents relapse during tapering of prednisolone doses. IL-6 is also heavily engaged in the remodeling of large vessels after acute aortic dissection as demonstrated in animal studies. In patients with acute aortic dissection, those with markedly elevated CRP levels in the acute phase are known to have an increased risk of aorta-related events, such as rupture due to aortic diameter enlargement, in the subacute and chronic phases. We discovered that elevated CRP levels following aortic dissection are caused by IL-6, which is produced by neutrophils that infiltrate the adventitia of the dissected aorta. In a mouse model of acute aortic dissection, we showed that IL-6 produced by these neutrophils causes progressive destruction of the arterial wall structure and that blockade of IL-6 signaling can prevent post-dissection vascular remodeling and improve life outcome. Therefore, inhibiting IL-6 signaling is anticipated to be effective in the secondary prevention of myocardial infarction and suppression of vascular modeling after dissection and even as an anti-inflammatory therapy for Takayasu's arteritis; however, this approach does not solve everything. Undoubtedly, the mechanisms of inflammation in vascular disease are diverse and complex, and the cytokines and cell populations involved at each site (coronary artery vs. aorta) and in each phenotype (atherosclerosis vs. aortic aneurysm vs. aortic dissection) need to be understood for each type of inflammation. Osteopontin (OPN) is a recruiter of monocytes and macrophages, induces cellular immune responses as a Th1 cytokine, acts as a fibrosis-promoting factor, and has been shown to be deeply involved in the pathogenesis of vascular diseases. We have shown that senescent T cells, which emerge with obesity and aging, secrete significant amounts of OPN, leading to metabolic abnormalities and chronic inflammation. Neutrophil extracellular traps (NETs) released from activated neutrophils have been shown to contribute to the pathogenesis of acute coronary syndromes (ACS) by interacting with macrophages, platelets, and vascular endothelial cells and thus promoting plaque erosion and immunothrombosis. In addition to standard anticoagulant and antiplatelet therapies, the effectiveness of anti-immunothrombotic therapies targeting NETs as a new preventive and therapeutic approach for ACS will be examined in the future.

Efficacy of inhaled hydrogen on neurological outcome following brain ischaemia during post-cardiac arrest care (HYBRID II): a multi-centre, randomised, double-blind, placebo-controlled trial.

Background: Inhaled molecular hydrogen gas (H2) has been shown to improve outcomes in animal models of cardiac arrest (CA). H2 inhalation is safe and feasible in patients after CA. We investigated whether inhaled H2 would improve outcomes after out-of-hospital CA (OHCA). Methods: HYBRID II is a prospective, multicentre, randomised, double-blind, placebo-controlled trial performed at 15 hospitals in Japan, between February 1, 2017, and September 30, 2021. Patients aged 20-80 years with coma following cardiogenic OHCA were randomly assigned (1:1) using blinded gas cylinders to receive supplementary oxygen with 2% H2 or oxygen (control) for 18 h. The primary outcome was the proportion of patients with a 90-day Cerebral Performance Category (CPC) of 1 or 2 assessed in a full-analysis set. Secondary outcomes included the 90-day score on a modified Rankin scale (mRS) and survival. HYBRID II was registered with the University Hospital Medical Information Network (registration number: UMIN000019820) and re-registered with the Japan Registry for Clinical Trials (registration number: jRCTs031180352). Findings: The trial was terminated prematurely because of the restrictions imposed on enrolment during the COVID-19 pandemic. Between February 1, 2017, and September 30, 2021, 429 patients were screened for eligibility, of whom 73 were randomly assigned to H2 (n = 39) or control (n = 34) groups. The primary outcome, i.e., a CPC of 1 or 2 at 90 days, was achieved in 22 (56%) and 13 (39%) patients in the H2 and control groups (relative risk compared with the control group, 0.72; 95% CI, 0.46-1.13; P = 0.15), respectively. Regarding the secondary outcomes, median mRS was 1 (IQR: 0-5) and 5 (1-6) in the H2 and control groups, respectively (P = 0.01). An mRS score of 0 was achieved in 18 (46%) and 7 (21%) patients in the H2 and control groups, respectively (P = 0.03). The 90-day survival rate was 85% (33/39) and 61% (20/33) in the H2 and control groups, respectively (P = 0.02). Interpretation: The increase in participants with good neurological outcomes following post-OHCA H2 inhalation in a selected population of patients was not statistically significant. However, the secondary outcomes suggest that H2 inhalation may increase 90-day survival without neurological deficits. Funding: Taiyo Nippon Sanso Corporation. Translation: For the Japanese translation of the abstract see Supplementary Materials section.

A Role of Sodium-Glucose Co-Transporter 2 in Cardiorenal Anemia Iron Deficiency Syndrome.

Heart failure, renal dysfunction, anemia, and iron deficiency affect each other and form a vicious cycle, a condition referred to as cardiorenal anemia iron deficiency syndrome. The presence of diabetes further accelerates this vicious cycle. Surprisingly, simply inhibiting sodium-glucose co-transporter 2 (SGLT2), which is expressed almost exclusively in the proximal tubular epithelial cells of the kidney, not only increases glucose excretion into the urine and effectively controls blood glucose levels in diabetes but can also correct the vicious cycle of cardiorenal anemia iron deficiency syndrome. This review describes how SGLT2 is involved in energy metabolism regulation, hemodynamics (i.e., circulating blood volume and sympathetic nervous system activity), erythropoiesis, iron bioavailability, and inflammatory set points in diabetes, heart failure, and renal dysfunction.

Improved prediction of sudden cardiac death in patients with heart failure through digital processing of electrocardiography.

AIMS: Available predictive models for sudden cardiac death (SCD) in heart failure (HF) patients remain suboptimal. We assessed whether the electrocardiography (ECG)-based artificial intelligence (AI) could better predict SCD, and also whether the combination of the ECG-AI index and conventional predictors of SCD would improve the SCD stratification among HF patients. METHODS AND RESULTS: In a prospective observational study, 4 tertiary care hospitals in Tokyo enrolled 2559 patients hospitalized for HF who were successfully discharged after acute decompensation. The ECG data during the index hospitalization were extracted from the hospitals' electronic medical record systems. The association of the ECG-AI index and SCD was evaluated with adjustment for left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) class, and competing risk of non-SCD. The ECG-AI index plus classical predictive guidelines (i.e. LVEF ≤35%, NYHA Class II and III) significantly improved the discriminative value of SCD [receiver operating characteristic area under the curve (ROC-AUC), 0.66 vs. 0.59; P = 0.017; Delong's test] with good calibration (P = 0.11; Hosmer-Lemeshow test) and improved net reclassification [36%; 95% confidence interval (CI), 9-64%; P = 0.009]. The Fine-Gray model considering the competing risk of non-SCD demonstrated that the ECG-AI index was independently associated with SCD (adjusted sub-distributional hazard ratio, 1.25; 95% CI, 1.04-1.49; P = 0.015). An increased proportional risk of SCD vs. non-SCD with an increasing ECG-AI index was also observed (low, 16.7%; intermediate, 18.5%; high, 28.7%; P for trend = 0.023). Similar findings were observed in patients aged ≤75 years with a non-ischaemic aetiology and an LVEF of >35%. CONCLUSION: To improve risk stratification of SCD, ECG-based AI may provide additional values in the management of patients with HF.

Pharmacokinetics of hydrogen administered intraperitoneally as hydrogen-rich saline and its effect on ischemic neuronal cell death in the brain in gerbils.

Intraperitoneal administration of hydrogen (H2)-containing saline inhibited neuronal cell death in ischemic stroke in a number of animal models, but it is unknown whether H2 is absorbed from the abdominal cavity into the blood and reaches the brain. In this study, we investigated whether intraperitoneal administration of saline containing H2 inhibits neuronal cell death caused by cerebral ischemia and measured the concentration of H2 in the carotid artery and inferior vena cava (IVC). Gerbils were subjected to transient unilateral cerebral ischemia twice, and saline or H2-rich saline was administered intraperitoneally three or seven times every 12 hours. We evaluated the number of apoptotic cells in the hippocampus and cerebral cortex on day 3 and the number of viable neurons in the hippocampus and cerebral cortex on day 7. In addition, a single dose of saline or H2-rich saline was administered intraperitoneally, and blood H2 levels in the carotid artery and IVC were measured. On day 3 of ischemia/reperfusion, the number of neurons undergoing apoptosis in the cortex was significantly lower in the H2-rich saline group than in the saline group, and on day 7, the number of viable neurons in the hippocampus and cerebral cortex was significantly higher in the H2-rich saline group. Intraperitoneal administration of H2-rich saline resulted in large increases in H2 concentration in the IVC ranging from 0.00183 mg/L (0.114%) to 0.00725 mg/L (0.453%). In contrast, carotid H2 concentrations remained in the range of 0.00008 mg/L (0.0049%) to 0.00023 (0.0146%). On average, H2 concentrations in carotid artery were 0.04 times lower than in IVC. These results indicate that intraperitoneal administration of H2-rich saline significantly suppresses neuronal cell death after cerebral ischemia, even though H2 hardly reaches the brain.

Global Characteristics and Dynamics of Single Immune Cells After Myocardial Infarction.

Background Myocardial infarction (MI) is characterized by the emergence of dead or dying cardiomyocytes and excessive immune cell infiltration after coronary vessel occlusion. However, the complex transcriptional profile, pathways, cellular interactome, and transcriptional regulators of immune subpopulations after MI remain elusive. Methods and Results Here, male C57BL/6 mice were subjected to MI surgery and monitored for 1 day and 7 days, or sham surgery for 7 days, then cardiac CD45-positive immune cells were collected for single-cell RNA sequencing to determine immune heterogeneity. A total of 30 135 CD45+ immune cells were partitioned into macrophages, monocytes, neutrophils, dendritic cells, and T or B cells for further analysis. We showed that macrophages enriched for Olr1 and differentially expressed Gpnmb represented 2 crucial ischemia-associated macrophages with distinct proinflammatory and prophagocytic capabilities. In contrast to the proinflammatory subset of macrophages enriched for Olr1, Gpnmb-positive macrophages exhibited higher phagocytosis and fatty acid oxidation preference, which could be abolished by etomoxir treatment. In addition to macrophages, MI triggered prompt recruitment of neutrophils into murine hearts, which constituted the sequential cell-fate from naïve S100a4-positive, to activated Sell-high, to aging Icam1-high neutrophils. In silico tools predicted that the excessively expanded neutrophils at 1 day were attributed to chemokine C-C motif ligand/chemokine C-X-C motif ligand pathways, whereas CD80/inducible T-cell costimulator (ICOS) signaling was responsible for the immunosuppressive response at day 7 after MI. Finally, the Fos/AP-1 (activator protein 1) regulon was identified as the critical regulator of proinflammatory responses, which was significantly activated in patients with dilated cardiomyopathy and ischemic cardiomyopathy. We showed the enriched Fos/AP-1 target gene loci in genome-wide association study signals for coronary artery diseases and MI. Targeting Fos/AP-1 with the selective inhibitor T5224 blunted leukocyte infiltration and alleviated cardiac dysfunction in the preclinical murine MI model. Conclusions Taken together, this single-cell RNA sequencing data lay the groundwork for the understanding of immune cell heterogeneity and dynamics in murine ischemic hearts. Moreover, Fos/AP-1 inhibition mitigates inflammatory responses and cardiac dysfunction, which might provide potential therapeutic benefits for heart failure intervention after MI.

Upregulation of neuropeptide Y in cardiac sympathetic nerves induces stress (Takotsubo) cardiomyopathy.

Substantial emotional or physical stress may lead to an imbalance in the brain, resulting in stress cardiomyopathy (SC) and transient left ventricular (LV) apical ballooning. Even though these conditions are severe, their precise underlying mechanisms remain unclear. Appropriate animal models are needed to elucidate the precise mechanisms. In this study, we established a new animal model of epilepsy-induced SC. The SC model showed an increased expression of the acute phase reaction protein, c-Fos, in the paraventricular hypothalamic nucleus (PVN), which is the sympathetic nerve center of the brain. Furthermore, we observed a significant upregulation of neuropeptide Y (NPY) expression in the left stellate ganglion (SG) and cardiac sympathetic nerves. NPY showed neither positive nor negative inotropic and chronotropic effects. On the contrary, NPY could interrupt ß-adrenergic signaling in cardiomyocytes when exposure to NPY precedes exposure to noradrenaline. Moreover, its elimination in the left SG via siRNA treatment tended to reduce the incidence of SC. Thus, our results indicated that upstream sympathetic activation induced significant upregulation of NPY in the left SG and cardiac sympathetic nerves, resulting in cardiac dysfunctions like SC.

Neutrophils and Neutrophil Extracellular Traps in Cardiovascular Disease: An Overview and Potential Therapeutic Approaches.

Recent advances in pharmacotherapy have markedly improved the prognosis of cardiovascular disease (CVD) but have not completely conquered it. Therapies targeting the NOD-like receptor family pyrin domain containing 3 inflammasome and its downstream cytokines have proven effective in the secondary prevention of cardiovascular events, suggesting that inflammation is a target for treating residual risk in CVD. Neutrophil-induced inflammation has long been recognized as important in the pathogenesis of CVD. Circadian rhythm-related and disease-specific microenvironment changes give rise to neutrophil diversity. Neutrophils are primed by various stimuli, such as chemokines, cytokines, and damage-related molecular patterns, and the activated neutrophils contribute to the inflammatory response in CVD through degranulation, phagocytosis, reactive oxygen species generation, and the release of neutrophil extracellular traps (NETs). In particular, NETs promote immunothrombosis through the interaction with vascular endothelial cells and platelets and are implicated in the development of various types of CVD, such as acute coronary syndrome, deep vein thrombosis, and heart failure. NETs are promising candidates for anti-inflammatory therapy in CVD, and their efficacy has already been demonstrated in various animal models of the disease; however, they have yet to be clinically applied in humans. This narrative review discusses the diversity and complexity of neutrophils in the trajectory of CVD, the therapeutic potential of targeting NETs, and the related clinical issues.

Treatment of transthyretin His88Arg amyloidosis with RNA interference therapy: A case report.

A new class of medicines called small interfering RNA molecule has demonstrated beneficial effects in patients with amyloidosis associated with mutations in transthyretin genes (ATTRv), but therapeutic effects towards His88Arg mutation were unknown. Here, we present two challenging cases of patisiran treatment for His88Arg variant. The first case is a 50-year-old male patient diagnosed with transthyretin amyloidosis cardiomyopathy with His88Arg mutation. Administration of patisiran 0.3 mg/kg every three weeks did not show any change in his symptoms. Echocardiography performed 1-year after drug initiation revealed progression of LV hypertrophy and systolic dysfunction with increased pleural effusion. The second case was a 63-year-old woman with heart failure (HF) caused by ATTRv cardiomyopathy with a His88Arg mutation. The patient began patisiran treatment 0.3 mg/kg every three weeks. Eleven months after beginning patisiran, her HF signs worsened with exacerbation of lung congestion and pleural effusion, resulting in hospitalization for decompensated HF. The two cases showed that treatment with patisiran for the patients with advanced stage of His88Arg ATTRv cardiomyopathy was unable to stop the progression of HF. Since the therapeutic response for each variant in ATTRv cardiomyopathy is unknown, further assessment of clinical efficacy for each individual variant is needed. .

Molecular Mechanism of Pathogenesis and Treatment Strategies for AL Amyloidosis.

In amyloid light-chain (AL) amyloidosis, small B-cell clones (mostly plasma cell clones) present in the bone marrow proliferate and secrete unstable monoclonal free light chains (FLCs), which form amyloid fibrils that deposit in the interstitial tissue, resulting in organ injury and dysfunction. AL amyloidosis progresses much faster than other types of amyloidosis, with a slight delay in diagnosis leading to a marked exacerbation of cardiomyopathy. In some cases, the resulting heart failure is so severe that chemotherapy cannot be administered, and death sometimes occurs within a few months. To date, many clinical studies have focused on therapeutics, especially chemotherapy, to treat this disease. Because it is necessary to promptly lower FLC, the causative protein of amyloid, to achieve a hematological response, various anticancer agents targeting neoplastic plasma cells are used for the treatment of this disease. In addition, many basic studies using human specimens to elucidate the pathophysiology of AL have been conducted. Gene mutations associated with AL, the characteristics of amyloidogenic LC, and the structural specificity of amyloid fibrils have been clarified. Regarding the mechanism of cellular and tissue damage, the mass effect due to amyloid deposition, as well as the toxicity of pre-fibrillar LC, is gradually being elucidated. This review outlines the pathogenesis and treatment strategies for AL amyloidosis with respect to its molecular mechanisms.

Development of a novel porcine ischemia/reperfusion model inducing different ischemia times in bilateral kidneys-effects of hydrogen gas inhalation.

Background: Acute kidney injury and its central pathology, renal ischemia reperfusion injury (IRI), have been studied in many animal models. Although renal IRI has been induced in pig models in many ways, simultaneous bilateral ischemia or unilateral ischemia along with contralateral nephrectomy models only provide data on the renal response to a single ischemia time. Moreover, it has been reported that prolonged renal ischemia time in pigs for 120 min or more can cause irreversible renal damage and increase animal mortality. Methods: We developed a model that induces prolonged ischemia time and subsequent reperfusion injury without threatening the lives of pigs by subjecting the left and right kidneys to ischemia for 120 and 60 min, respectively. Using this novel model, we investigated whether hydrogen gas inhalation could alleviate renal IRI. Results: All animals (n=4) survived until the end of the observation period of 3 months in this model. Evaluation of the left and right kidneys immediately before and after IRI could be performed separately by blood sampling from each renal vein and renal biopsy during surgery, although the results of peripheral blood sampling during the follow-up were the mixed results of bilateral kidneys. The release of degraded DNA from the kidneys immediately after IRI and subsequent renal fibrosis at 3 months increased in response to ischemia time. Although the effect of hydrogen gas on pathological findings was not obvious, the release of degraded DNA from the kidney, an acute marker of IRI, appeared to be suppressed. Conclusions: We have developed a novel model in which IRI of different ischemia times is induced in the bilateral kidney that provides two-fold information and allows for safe long-term observation experiments in pigs. Using this model, hydrogen gas inhalation appeared to reduce acute renal IRI, although the effect was not statistically significant.