Association of Regression from Sustained to Paroxysmal Atrial Fibrillation With Clinical Outcomes: The Fushimi AF Registry.

In some cases, albeit infrequently, patients with atrial fibrillation (AF) may experience a regression from a sustained to a paroxysmal type. We sought to investigate how regression of AF is associated with outcomes. Among the patients with AF enrolled in the Fushimi AF Registry who were identified as having sustained AF at baseline, conversion of sustained to paroxysmal AF during follow-up was defined as AF regression. Major adverse cardiovascular events (MACEs) were defined as a composite of cardiac death, myocardial infarction, ischemic stroke, systemic embolism, or hospitalization due to heart failure. Among 2,261 patients with sustained AF at baseline, AF regression was observed in 214 (9.5%) patients over a median follow-up period of 5.8 years (1.78% per patient-year). The annual incidence of MACE was significantly lower in patients with AF regression than in those without (3.47% vs 6.59% per patient-year, p <0.001, adjusted hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.38 to 0.72). Furthermore, AF regression was significantly associated with reduced risk of MACE during and after the regression period from sustained to paroxysmal forms (during the regression period: adjusted HR 0.45, 95% CI 0.22 to 0.90; after the regression period: adjusted HR 0.43, 95% CI 0.26 to 0.67). The incidence of MACE was comparable between spontaneous regression (35/178: 19.7%) and therapy-associated regression (either receiving catheter ablation or antiarrhythmic drugs before the regression) (7/36: 19.4%) (p = 0.98). Regression of AF was associated with lower incidence of adverse cardiovascular events. The risk of adverse events decreased significantly during the regression period, and this reduced risk persisted after regression. Clinical Trial Registration: URL: http://www.umin.ac.jp/ctr/index.htm Unique identifier: UMIN000005834.

Association of left atrial enlargement with heart failure events in non-valvular atrial fibrillation patients with preserved left ventricular ejection fraction.

Aims: Atrial fibrillation (AF) increases the risk of heart failure (HF); however, little is known regarding the risk stratification for incident HF in AF patients, especially with preserved left ventricular ejection fraction (LVEF). Methods and results: The Fushimi AF Registry is a community-based prospective survey of AF patients. From the registry, 3002 non-valvular AF patients with preserved LVEF and with the data of antero-posterior left atrial diameter (LAD) at enrolment were investigated. Patients were stratified by LAD (<40, 40-44, 45-49, and ≥50 mm) with backgrounds and HF hospitalization incidences compared between groups. Of 3002 patients [mean age, 73.5 ± 10.7 years; women, 1226 (41%); paroxysmal AF, 1579 (53%); and mean CHA2DS2-VASc score, 3.3 ± 1.7], the mean LAD was 43 ± 8 mm. Patients with larger LAD were older and less often paroxysmal AF, with a higher CHA2DS2-VASc score (all P < 0.001). Heart failure hospitalization occurred in 412 patients during the median follow-up period of 6.0 years. Larger LAD was independently associated with a higher HF hospitalization risk [LAD ≥ 50 mm: hazard ratio (HR), 2.36; 95% confidence interval (CI), 1.75-3.18; LAD 45-49 mm: HR, 1.84; 95% CI, 1.37-2.46; and LAD 40-44 mm: HR, 1.34; 95% CI, 1.01-1.78, compared with LAD < 40 mm) after adjustment by age, sex, AF type, and CHA2DS2-VASc score. These results were also consistent across major subgroups, showing no significant interaction. Conclusion: Left atrial diameter is significantly associated with the risk of incident HF in AF patients with preserved LVEF, suggesting the utility of LAD regarding HF risk stratification for these patients.

KUS121, a VCP modulator, has an ameliorating effect on acute and chronic heart failure without calcium loading via maintenance of intracellular ATP levels.

AIMS: As heart failure (HF) progresses, ATP levels in myocardial cells decrease, and myocardial contractility also decreases. Inotropic drugs improve myocardial contractility but increase ATP consumption, leading to poor prognosis. Kyoto University Substance 121 (KUS121) is known to selectively inhibit the ATPase activity of valosin-containing protein, maintain cellular ATP levels, and manifest cytoprotective effects in several pathological conditions. The aim of this study is to determine the therapeutic effect of KUS121 on HF models. METHODS AND RESULTS: Cultured cell, mouse, and canine models of HF were used to examine the therapeutic effects of KUS121. The mechanism of action of KUS121 was also examined. Administration of KUS121 to a transverse aortic constriction (TAC)-induced mouse model of HF rapidly improved the left ventricular ejection fraction and improved the creatine phosphate/ATP ratio. In a canine model of high frequency-paced HF, administration of KUS121 also improved left ventricular contractility and decreased left ventricular end-diastolic pressure without increasing the heart rate. Long-term administration of KUS121 to a TAC-induced mouse model of HF suppressed cardiac hypertrophy and fibrosis. In H9C2 cells, KUS121 reduced ER stress. Finally, in experiments using primary cultured cardiomyocytes, KUS121 improved contractility and diastolic capacity without changing peak Ca2+ levels or contraction time. These effects were not accompanied by an increase in cyclic adenosine monophosphate or phosphorylation of phospholamban and ryanodine receptors. CONCLUSIONS: KUS121 ameliorated HF by a mechanism totally different from that of conventional catecholamines. We propose that KUS121 is a promising new option for the treatment of HF.

Differential response to isometric handgrip depending on the heart failure condition in patients with functional mitral regurgitation: a case report.

Background: Functional mitral regurgitation (MR) changes dynamically depending on the loading conditions and can cause acute heart failure (HF). Isometric handgrip is a simple stress test and can be performed during early phase of acute HF for the evaluation of MR. Case summary: A 70-year-old woman with a prior myocardial infarction four months before, and with history of recurrent HF admission with functional MR, who received optimal HF medications, was hospitalized for acute HF. On the following day of the admission, isometric handgrip stress echocardiography was performed to evaluate functional MR. During the handgrip, MR deteriorated from moderate to severe and the tricuspid regurgitation pressure gradient increased from 45 to 60 mmHg. After HF stabilization 2 weeks after admission, repeat handgrip stress echocardiography showed that the degree of MR did not significantly change being moderate and the tricuspid regurgitation pressure gradient was only mildly elevated from 25 to 30 mmHg. She underwent transcatheter edge-to-edge mitral repair, and thereafter she has not experienced the rehospitalization for acute HF. Discussion: Exercise stress test is recommended for the evaluation of functional MR in HF patients; however, exercise tests are difficult to perform during the early phase of acute HF. In this regard, handgrip test is an option to investigate the exacerbating impact of functional MR during early-phase acute HF. This case indicated that response to isometric handgrip can vary depending on HF condition, highlighting the importance of taking into account the timing of the handgrip procedure in patients with functional MR and HF.

Proteinuria is independently associated with heart failure events in patients with atrial fibrillation: the Fushimi AF registry.

AIMS: Previous studies have shown that proteinuria is independently associated with the incidence of atrial fibrillation (AF), and is also associated with the incidence of cardiovascular events such as stroke and thromboembolism in patients with AF. However, the association of proteinuria with heart failure (HF) events in patients with AF remains unclear. METHODS AND RESULTS: The Fushimi AF Registry is a community-based prospective study of patients with AF. Of the entire cohort of 4489 patients, 2164 patients had available data of proteinuria. We compared the clinical background and outcomes between patients with proteinuria (n = 606, 28.0%) and those without (n = 1558, 72.0%). Patients with proteinuria were older and had a higher prevalence of major co-morbidities. During the median follow-up of 5.0 years, the incidence rates of HF events (composite of cardiac death or HF hospitalization) were higher in patients with proteinuria than those without (4.1% vs. 2.1% person-year, P < 0.01). Multivariate analyses revealed that proteinuria was an independent risk factor of the incidence of HF events [adjusted hazard ratio (HR): 1.40, 95% confidence interval (CI): 1.13-1.74]. This association was consistent among the various subgroups, except for the age subgroup in which there was a significant interaction (P < 0.01) between younger (<75 years) (unadjusted HR: 3.03, 95% CI: 2.12-4.34) and older (≥75 years) patients (unadjusted HR: 1.59, 95% CI: 1.23-2.05). CONCLUSION: Our community-based large prospective cohort suggests that proteinuria is independently associated with the incidence of HF events in Japanese patients with AF.

A case of infective endocarditis mimicking antineutrophil cytoplasmic antibody-associated vasculitis.

Infective endocarditis (IE) is not a common disease, but it remains a serious condition. Antineutrophil cytoplasmic antibodies (ANCA) are often positive in IE, and discrimination between IE and ANCA-associated vasculitis is important because misdirected selection of therapy can lead to catastrophic consequences. We report a case of IE mimicking ANCA-associated vasculitis in which we were able to make a correct diagnosis and perform treatment. This case suggests that it is important to consider IE as a differential diagnosis in ANCA-positive patients. Learning objective: Antineutrophil cytoplasmic antibodies (ANCA) are associated with primary systemic vasculitis. However, ANCA have also been described in other conditions and infective endocarditis (IE) was considered an important cause of ANCA.Discrimination between IE and ANCA-associated vasculitis is important, although it is sometimes difficult. We report a case of IE mimicking ANCA-associated vasculitis. ANCA-positive patients with nonspecific symptoms should be suspected of having IE, checked for heart murmurs, and tested by echocardiography and blood cultures.

Association of Concomitant Coronary Artery Disease With Cardiovascular Events in Patients With Atrial Fibrillation　- The Fushimi AF Registry.

BACKGROUND: Atrial fibrillation (AF) patients often have concomitant coronary artery disease (CAD); however, there are little data on clinical characteristics and outcomes of such patients in daily clinical practice in Japan.Methods and Results: The Fushimi AF Registry is a community-based prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. Follow-up data were available for 4,464 patients, and the median follow up was 5.1 (interquartile range: 2.3-8.0) years. History of CAD was present in 647 patients (14%); of those patients, 267 (41%) had history of myocardial infarction (MI). Patients with CAD were older and had more comorbidities than those without CAD. The crude incidences (% per patient-year) of cardiovascular events were significantly higher in patients with CAD than those without CAD (cardiac death: 1.8 vs. 0.7, stroke or systemic embolism [SE]: 2.9 vs. 2.1, MI: 0.6 vs. 0.1, composite of those events: 5.1 vs. 2.8, respectively, all log-rank P<0.01). After multivariate adjustment, concomitant CAD was associated with incidence of cardiac events, and history of MI was associated with incidence of MI; however, neither history of CAD nor MI was associated with the incidence of stroke/SE. CONCLUSIONS: In Japanese AF patients, concomitant CAD was associated with higher prevalences of major co-morbidities and higher incidences of cardiovascular events; however, history of CAD was not associated with the incidence of stroke/SE.

Impacts of KF Post-Deposition Treatment on the Band Alignment of Epitaxial Cu(In,Ga)Se2 Heterojunctions.

In this study, we investigated band alignments at CdS/epitaxial CuInxGa1-xSe2 (epi-CIGSe) and epi-CIGSe/GaAs heterointerfaces for solar cell applications using ultraviolet, inverse, and X-ray photoemission spectroscopy (UPS, IPES, and XPS) techniques. We clarified the impacts of KF postdeposition treatment (KF-PDT) at the CdS/epi-CIGSe front heterointerfaces. We found that KF-PDT changed the conduction band alignment at the CdS/epi-CIGSe heterointerface from a cliff to flat configuration, attributed to an increase in the electron affinity (EA) and ionization potential (IP) of the epi-CIGSe surface because of a decrease in Cu and Ga contents. Herein, we discuss the correlation between the impacts of KF-PDT and the solar cell performance. Furthermore, we also investigated the band alignment at the epi-CIGSe/GaAs rear heterointerface. Electron barriers were formed at the epi-CIGSe/GaAs interface, suppressing carrier recombination as the back surface field. Contrarily, a hole accumulation layer is formed by the valence band bending, which is like Ohmic contact.

10-Year Trends of Antithrombotic Therapy Status and Outcomes in Japanese Atrial Fibrillation Patients　- The Fushimi AF Registry.

BACKGROUND: Atrial fibrillation (AF) increases the risk of stroke and death. Oral anticoagulants (OAC) are highly effective in reducing the risk of stroke, and direct oral anticoagulants (DOAC) became available worldwide in 2011.Methods and Results:The Fushimi AF Registry is an on-going prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. The study cohort consisted of 4,489 patients (mean age 73.6 years, 59.6% male, mean CHADS2score 2.03), enrolled in 2011-2017. From 2011 to 2021, antithrombotic therapy has undergone a major transition; the proportion of patients receiving OAC has increased from 53% to 70%, with a steady uptake of DOAC (from 2% to 52%), whereas the proportion of patients receiving antiplatelet agents has decreased from 32% to 14%. Over a median follow-up of 5.1 years, the incidence of stroke/systemic embolism (SE), major bleeding, and all-cause death was 2.2%, 1.9%, and 4.9% per patient-year, respectively. The incidence of stroke/SE (1.6% vs. 2.3%; P<0.01), major bleeding (1.6% vs. 2.0%; P=0.07), and death (4.2% vs. 5.0%; P<0.01) was lower among patients enrolled in 2014-2017 than in 2011-2013, despite comparable baseline characteristics (age 73.2 vs. 73.7 years, CHADS2score 2.03 vs. 2.04, and HAS-BLED score 1.67 vs. 1.77, respectively). CONCLUSIONS: Over the past 10 years, there has been a major transition in antithrombotic therapy and a decline in the incidence of adverse events in AF patients.

Isometric Handgrip Stress Test during Right Heart Catheterization in Patients with Mitral Regurgitation -A Case Series Study.

Objective The severity of mitral regurgitation (MR) dynamically changes during a stress test. Isometric handgrip is a readily-available stress test in daily practice; however, little is known regarding the response to isometric handgrip in MR patients during right heart catheterization. We aimed to evaluate this issue from our case-series study. Methods We retrospectively investigated consecutive MR patients using the isometric handgrip stress test during right heart catheterization at our institution between October 2019 and April 2021. After resting measurements were obtained, sustained maximum-effort hand dynamometer grasping was maintained for about 2-3 minutes. We investigated the differences in right heart catheterization data between at rest and during handgrip, and evaluated the individual response to the isometric handgrip stress test. Results We investigated a total of 15 patients (mean age: 75±6 years, moderate/severe MR: 7/8, primary/secondary MR: 8/7, mean left ventricular ejection fraction: 56±16%, exertional dyspnea: 10). During the handgrip test, the pulmonary capillary wedge pressure (PCWP) significantly increased [9 (8, 13) mmHg at rest to 20 (15, 27) mmHg during handgrip; p<0.001]. PCWP changes varied among individuals (range 2-22 mmHg) and were not correlated with patients' backgrounds including age, the natriuretic peptide levels, left ventricular ejection fraction, left atrial diameter or E/e' (all p>0.05). Patients with PCWP ≥25 mmHg during handgrip had a higher prevalence of exertional dyspnea than those without [6 (100%) vs. 4 (44%); p=0.04]. Conclusion We observed dynamic and varied hemodynamic changes during isometric handgrip in MR patients, suggesting that further research is needed to evaluate the clinical value of this maneuver.

Clinical Characteristics and Outcomes of Very Elderly Patients With Atrial Fibrillation at High Bleeding Risk　- The Fushimi AF Registry.

Background: The ELDERCARE-AF trial demonstrated that low-dose edoxaban prevented stroke or systemic embolism (SE) in very elderly Japanese patients with non-valvular atrial fibrillation (NVAF) in whom standard oral anticoagulant therapy was inappropriate because of high bleeding risk. The aim of this study was to elucidate the characteristics and outcomes of such patients in routine clinical practice. Methods and Results: Data were extracted from the Fushimi AF Registry for ELDERCARE-eligible NVAF patients aged ≥80 years, with a CHADS2 score ≥2 and ≥1 bleeding risk factors, as shown in the ELDERCARE-AF trial. ELDERCARE-eligible patients (n=549; 12.8% of the entire cohort, 52.9% of those aged ≥80 years and with CHADS2 score ≥2) were less often male, were older, had more comorbidity and higher risk scores than non-eligible patients from the entire cohort (n=3,734). The crude incidence (% per patient-year) of adverse events was significantly higher in ELDERCARE-eligible than non-eligible patients (stroke/SE, 4.8% vs. 2.0%; major bleeding, 3.6% vs. 1.9%; all-cause mortality, 15.5% vs. 3.9%; cardiovascular death, 2.7% vs. 0.6%; all log-rank P<0.001). Compared with non-eligible patients aged ≥80 years and with a CHADS2 score ≥2 (n=488), the incidence of stroke/SE, all-cause mortality, and cardiovascular death remained significantly higher in ELDERCARE-eligible patients. Conclusions: Patients with NVAF who met the inclusion criteria of the ELDERCARE-AF trial were common in routine clinical practice, and had poor clinical outcomes.

Characteristics and clinical outcomes in atrial fibrillation patients classified using cluster analysis: the Fushimi AF Registry.

AIMS: The risk of adverse events in atrial fibrillation (AF) patients was commonly stratified by risk factors or clinical risk scores. Risk factors often do not occur in isolation and are often found in multimorbidity 'clusters' which may have prognostic implications. We aimed to perform cluster analysis in a cohort of AF patients and to assess the outcomes and prognostic implications of the identified comorbidity cluster phenotypes. METHODS AND RESULTS: The Fushimi AF Registry is a community-based prospective survey of the AF patients in Fushimi-ku, Kyoto, Japan. Hierarchical cluster analysis was performed on 4304 patients (mean age: 73.6 years, female; 40.3%, mean CHA2DS2-VASc score 3.37 ± 1.69), using 42 baseline clinical characteristics. On hierarchical cluster analysis, AF patients could be categorized into six statistically driven comorbidity clusters: (i) younger ages (mean age: 48.3 years) with low prevalence of risk factors and comorbidities (n = 209); (ii) elderly (mean age: 74.0 years) with low prevalence of risk factors and comorbidities (n = 1301); (iii) those with high prevalence of atherosclerotic risk factors, but without atherosclerotic disease (n = 1411); (iv) those with atherosclerotic comorbidities (n = 440); (v) those with history of any-cause stroke (n = 681); and (vi) the very elderly (mean age: 83.4 years) (n = 262). Rates of all-cause mortality and major adverse cardiovascular or neurological events can be stratified by these six identified clusters (log-rank test; P < 0.001 and P < 0.001, respectively). CONCLUSIONS: We identified six clinically relevant phenotypes of AF patients on cluster analysis. These phenotypes can be associated with various types of comorbidities and associated with the incidence of clinical outcomes. CLINICAL TRIAL REGISTRATION INFORMATION: https://www.umin.ac.jp/ctr/index.htm. Unique identifier: UMIN000005834.

microRNA-33 maintains adaptive thermogenesis via enhanced sympathetic nerve activity.

Adaptive thermogenesis is essential for survival, and therefore is tightly regulated by a central neural circuit. Here, we show that microRNA (miR)-33 in the brain is indispensable for adaptive thermogenesis. Cold stress increases miR-33 levels in the hypothalamus and miR-33-/- mice are unable to maintain body temperature in cold environments due to reduced sympathetic nerve activity and impaired brown adipose tissue (BAT) thermogenesis. Analysis of miR-33f/f dopamine-ß-hydroxylase (DBH)-Cre mice indicates the importance of miR-33 in Dbh-positive cells. Mechanistically, miR-33 deficiency upregulates gamma-aminobutyric acid (GABA)A receptor subunit genes such as Gabrb2 and Gabra4. Knock-down of these genes in Dbh-positive neurons rescues the impaired cold-induced thermogenesis in miR-33f/f DBH-Cre mice. Conversely, increased gene dosage of miR-33 in mice enhances thermogenesis. Thus, miR-33 in the brain contributes to maintenance of BAT thermogenesis and whole-body metabolism via enhanced sympathetic nerve tone through suppressing GABAergic inhibitory neurotransmission. This miR-33-mediated neural mechanism may serve as a physiological adaptive defense mechanism for several stresses including cold stress.

Cardiovascular Events and Mortality in Patients With Atrial Fibrillation and Anemia (from the Fushimi AF Registry).

Data regarding the associations of anemia (hemoglobin level <13.0 g/dl in men and <12.0 g/dl in women) with clinical outcomes in patients with atrial fibrillation (AF) remains scarce. This study sought to investigate the associations of anemia with the incidences of stroke or systemic embolism, major bleeding, heart failure (HF) hospitalization, and all-cause mortality including its causes, using the data from a Japanese community-based survey, the Fushimi AF Registry. A total of 4,169 AF patients were divided into the 3 groups, based on the baseline hemoglobin level: no (n = 2,622), mild (11.0 to <13.0 g/dl for men and <12.0 g/dl for women; n = 880), and moderate/severe anemia (<11.0 g/dl; n = 667). During a median follow-up of 1,464 days, the incidences of major bleeding, HF hospitalization, and mortality increased with higher rates of cardiac death, in accordance with anemic severity. On multivariate analyses, the higher risk of moderate/severe anemia, relative to no anemia, for major bleeding remained statistically significant (hazard ratio [HR]: 2.00, 95% confidential interval [CI]: 1.48 to 2.72). The risks of those with anemia, relative to no anemia, for HF hospitalization (mild; HR: 1.87, 95% CI: 1.51 to 2.31, and moderate/severe; HR: 2.02, 95% CI: 1.59 to 2.57) as well as for mortality (mild; HR: 1.80, 95% CI: 1.50 to 2.16, and moderate/severe; HR: 2.95, 95% CI: 2.45 to 3.55) were also higher, but not for stroke/systemic embolism. These relations were consistent, regardless of the use of oral anticoagulants. In conclusion, anemia was associated with higher risks of HF hospitalization, mortality, and major bleeding in AF patients.

Lionheart LincRNA alleviates cardiac systolic dysfunction under pressure overload.

Recent high-throughput approaches have revealed a vast number of transcripts with unknown functions. Many of these transcripts are long noncoding RNAs (lncRNAs), and intergenic region-derived lncRNAs are classified as long intergenic noncoding RNAs (lincRNAs). Although Myosin heavy chain 6 (Myh6) encoding primary contractile protein is down-regulated in stressed hearts, the underlying mechanisms are not fully clarified especially in terms of lincRNAs. Here, we screen upregulated lincRNAs in pressure overloaded hearts and identify a muscle-abundant lincRNA termed Lionheart. Compared with controls, deletion of the Lionheart in mice leads to decreased systolic function and a reduction in MYH6 protein levels following pressure overload. We reveal decreased MYH6 results from an interaction between Lionheart and Purine-rich element-binding protein A after pressure overload. Furthermore, human LIONHEART levels in left ventricular biopsy specimens positively correlate with cardiac systolic function. Our results demonstrate Lionheart plays a pivotal role in cardiac remodeling via regulation of MYH6.

Homeobox A4 suppresses vascular remodeling by repressing YAP/TEAD transcriptional activity.

The Hippo signaling pathway is involved in the pathophysiology of various cardiovascular diseases. Yes-associated protein (YAP) and transcriptional enhancer activator domain (TEAD) transcriptional factors, the main transcriptional complex of the Hippo pathway, were recently identified as modulators of phenotypic switching of vascular smooth muscle cells (VSMCs). However, the intrinsic regulator of YAP/TEAD-mediated gene expressions involved in vascular pathophysiology remains to be elucidated. Here, we identified Homeobox A4 (HOXA4) as a potent repressor of YAP/TEAD transcriptional activity using lentiviral shRNA screen. Mechanistically, HOXA4 interacts with TEADs and attenuates YAP/TEAD-mediated transcription by competing with YAP for TEAD binding. We also clarified that the expression of HOXA4 is relatively abundant in the vasculature, especially in VSMCs. In vitro experiments in human VSMCs showed HOXA4 maintains the differentiation state of VSMCs via inhibition of YAP/TEAD-induced phenotypic switching. We generated Hoxa4-deficient mice and confirmed the downregulation of smooth muscle-specific contractile genes and the exacerbation of vascular remodeling after carotid artery ligation in vivo. Our results demonstrate that HOXA4 is a repressor of VSMC phenotypic switching by inhibiting YAP/TEAD-mediated transcription.

Cardioprotective Effects of VCP Modulator KUS121 in Murine and Porcine Models of Myocardial Infarction.

No effective treatment is yet available to reduce infarct size and improve clinical outcomes after acute myocardial infarction by enhancing early reperfusion therapy using primary percutaneous coronary intervention. The study showed that Kyoto University Substance 121 (KUS121) reduced endoplasmic reticulum stress, maintained adenosine triphosphate levels, and ameliorated the infarct size in a murine cardiac ischemia and reperfusion injury model. The study confirmed the cardioprotective effect of KUS121 in a porcine ischemia and reperfusion injury model. These findings confirmed that KUS121 is a promising novel therapeutic agent for myocardial infarction in conjunction with primary percutaneous coronary intervention.

Identification of Differential Roles of MicroRNA-33a and -33b During Atherosclerosis Progression With Genetically Modified Mice.

Background Micro RNA (miR)-33 targets cholesterol transporter ATP -binding cassette protein A1 and other antiatherogenic targets and contributes to atherogenic progression. Its inhibition or deletion is known to result in the amelioration of atherosclerosis in mice. However, mice lack the other member of the miR-33 family, miR-33b, which exists in humans and other large mammals. Thus, precise evaluation and comparison of the responsibilities of these 2 miRs during the progression of atherosclerosis has not been reported, although they are essential. Methods and Results In this study, we performed a comprehensive analysis of the difference between the function of miR-33a and miR-33b using genetically modified mice. We generated 4 strains with or without miR-33a and miR-33b. Comparison between mice with only miR-33a (wild-type mice) and mice with only miR-33b (miR-33a-/-/miR-33b+/+) revealed the dominant expression of miR-33b in the liver. To evaluate the whole body atherogenic potency of miR-33a and miR-33b, we developed apolipoprotein E-deficient/miR-33a+/+/miR-33b-/- mice and apolipoprotein E-deficient/miR-33a-/-/miR-33b+/+ mice. With a high-fat and high-cholesterol diet, the apolipoprotein E-deficient/miR-33a-/-/miR-33b+/+ mice developed increased atherosclerotic plaque versus apolipoprotein E-deficient/miR-33a+/+/miR-33b-/- mice, in line with the predominant expression of miR-33b in the liver and worsened serum cholesterol profile. By contrast, a bone marrow transplantation study showed no significant difference, which was consistent with the relevant expression levels of miR-33a and miR-33b in bone marrow cells. Conclusions The miR-33 family exhibits differences in distribution and regulation and particularly in the progression of atherosclerosis; miR-33b would be more potent than miR-33a.

MiR-33a is a therapeutic target in SPG4-related hereditary spastic paraplegia human neurons.

Recent reports, including ours, have indicated that microRNA (miR)-33 located within the intron of sterol regulatory element binding protein (SREBP) 2 controls cholesterol homeostasis and can be a potential therapeutic target for the treatment of atherosclerosis. Here, we show that SPAST, which encodes a microtubule-severing protein called SPASTIN, was a novel target gene of miR-33 in human. Actually, the miR-33 binding site in the SPAST 3'-UTR is conserved not in mice but in mid to large mammals, and it is impossible to clarify the role of miR-33 on SPAST in mice. We demonstrated that inhibition of miR-33a, a major form of miR-33 in human neurons, via locked nucleic acid (LNA)-anti-miR ameliorated the pathological phenotype in hereditary spastic paraplegia (HSP)-SPG4 patient induced pluripotent stem cell (iPSC)-derived cortical neurons. Thus, miR-33a can be a potential therapeutic target for the treatment of HSP-SPG4.

Hepatokine α1-Microglobulin Signaling Exacerbates Inflammation and Disturbs Fibrotic Repair in Mouse Myocardial Infarction.

Acute cardiac rupture and adverse left ventricular (LV) remodeling causing heart failure are serious complications of acute myocardial infarction (MI). While cardio-hepatic interactions have been recognized, their role in MI remains unknown. We treated cultured cardiomyocytes with conditioned media from various cell types and analyzed the media by mass spectrometry to identify α1-microglobulin (AM) as an Akt-activating hepatokine. In mouse MI model, AM protein transiently distributed in the infarct and border zones during the acute phase, reflecting infiltration of AM-bound macrophages. AM stimulation activated Akt, NFκB, and ERK signaling and enhanced inflammation as well as macrophage migration and polarization, while inhibited fibrogenesis-related mRNA expression in cultured macrophages and cardiac fibroblasts. Intramyocardial AM administration exacerbated macrophage infiltration, inflammation, and matrix metalloproteinase 9 mRNA expression in the infarct and border zones, whereas disturbed fibrotic repair, then provoked acute cardiac rupture in MI. Shotgun proteomics and lipid pull-down analysis found that AM partly binds to phosphatidic acid (PA) for its signaling and function. Furthermore, systemic delivery of a selective inhibitor of diacylglycerol kinase α-mediated PA synthesis notably reduced macrophage infiltration, inflammation, matrix metalloproteinase activity, and adverse LV remodeling in MI. Therefore, targeting AM signaling could be a novel pharmacological option to mitigate adverse LV remodeling in MI.