Published papers

© 2020 The Authors Overloading of the saturated fatty acid (SFA) palmitate induces cardiomyocyte death. The purpose of this study is to elucidate signaling pathways contributing to palmitate-induced cardiomyocyte death. Palmitate-induced cardiomyocyte death was induced in Toll-like receptor 2/4 double-knockdown cardiomyocytes to a similar extent as wild-type cardiomyocytes, while cardiomyocyte death was canceled out by triacsin C, a long-chain acyl-CoA synthetase inhibitor. These results indicated that palmitate induced cytotoxicity after entry and conversion into palmitoyl-CoA. Palmitoyl-CoA is not only degraded by mitochondrial oxidation but also taken up as a component of membrane phospholipids. Palmitate overloading causes cardiomyocyte membrane fatty acid (FA) saturation, which is associated with the activation of endoplasmic reticulum (ER) unfolded protein response (UPR) signaling. We focused on the ER UPR signaling as a possible mechanism of cell death. Palmitate loading activates the UPR signal via membrane FA saturation, but not via unfolded protein overload in the ER since the chemical chaperone 4-phenylbutyrate failed to suppress palmitate-induced ER UPR. The mammalian UPR relies on three ER stress sensors named inositol requiring enzyme-1 (IRE1), PKR-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6). Palmitate loading activated only IRE1 and PERK. Knockdown of PERK did not affect palmitate-induced cardiomyocyte death, while knockdown of IRE1 suppressed palmitate-induced cardiomyocyte death. However, knockdown of X-box binding protein 1 (XBP1), the downstream effector of IRE1, did not affect palmitate-induced cardiomyocyte death. These results were validated by pharmacological inhibitor experiments. In conclusion, we identified that palmitate-induced cardiomyocyte death was triggered by IRE1-mediated signaling independent of XBP1.

© 2020 Sano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The benefits of inhaling hydrogen gas (H2) have been widely reported but its pharmacokinetics have not yet been sufficiently analyzed. We developed a new experimental system in pigs to closely evaluate the process by which H2 is absorbed in the lungs, enters the bloodstream, and is distributed, metabolized, and excreted. We inserted and secured catheters into the carotid artery (CA), portal vein (PV), and supra-hepatic inferior vena cava (IVC) to allow repeated blood sampling and performed bilateral thoracotomy to collapse the lungs. Then, using a hydrogen-absorbing alloy canister, we filled the lungs to the maximum inspiratory level with 100% H2. The pig was maintained for 30 seconds without resuming breathing, as if they were holding their breath. We collected blood from the three intravascular catheters after 0, 3, 10, 30, and 60 minutes and measured H2 concentration by gas chromatography. H2 concentration in the CA peaked immediately after breath holding; 3 min later, it dropped to 1/40 of the peak value. Peak H2 concentrations in the PV and IVC were 40% and 14% of that in the CA, respectively. However, H2 concentration decay in the PV and IVC (half-life: 310 s and 350 s, respectively) was slower than in the CA (half-life: 92 s). At 10 min, H2 concentration was significantly higher in venous blood than in arterial blood. At 60 min, H2 was detected in the portal blood at a concentration of 6.9–53 nL/mL higher than at steady state, and in the SVC 14–29 nL/mL higher than at steady state. In contrast, H2 concentration in the CA decreased to steady state levels. This is the first report showing that inhaled H2 is transported to the whole body by advection diffusion and metabolized dynamically.

© 2019 International Society for Heart and Lung Transplantation BACKGROUND: A variant of c.14429G>A (p.Arg4810Lys, rs112735431) in the ring finger protein 213 gene (RNF213; NM_001256071.2) has been recently identified as a risk allele for pulmonary arterial hypertension (PAH). PAH can be added as a new member of RNF213-associated vascular diseases, which include Moyamoya disease and peripheral pulmonary stenosis. Our aim was to identify the clinical features and outcomes of PAH patients with this variant. METHODS: Whole-exome sequencing was performed in 139 idiopathic (or possibly heritable) PAH patients. RESULTS: The RNF213 p.Arg4810Lys variant was identified in a heterozygous state in 11 patients (7.9%). Time-course changes in hemodynamics after combination therapy in the patients with the RNF213 p.Arg4810Lys variant were significantly poorer compared with those carrying the bone morphogenic protein receptor type 2 (BMPR2) mutation (n = 36) (comparison of changes in mean pulmonary arterial pressure, p = 0.007). The event-free rate of death or lung transplantation was significantly poorer in RNF213 p.Arg4810Lys variant carriers than in BMPR2 mutation carriers (5-year event-free rate since the introduction of prostaglandin I2 infusion, 0% vs 93%, respectively; p < 0.001). CONCLUSIONS: Idiopathic PAH patients with the RNF213 p.Arg4810Lys variant are associated with poor clinical outcomes even in recent times. Earlier consideration of lung transplantation might be required for RNF213 p.Arg4810Lys variant carriers who are developing PAH. Documentation of the RNF213 p.Arg4810Lys variant, as well as already known pathogenic genes, such as BMPR2, can provide clinically relevant information for therapeutic strategies, leading to a personalized approach for the treatment of PAH.

© 2019 Glucocorticoid receptor (GR) is abundantly expressed in cardiomyocytes. However, the role of GR in regulating cardiac hypertrophy and heart failure in response to pressure overload remains unclear. Cardiomyocyte-specific GR knockout (GRcKO) mice, mineralocorticoid receptor (MR) knockout (MRcKO), and GR and MR double KO (GRMRdcKO) mice were generated using the Cre-lox system. In response to pressure overload, GRcKO mice displayed worse cardiac remodeling compared to control (GR f/f ) mice, including a greater increase in heart weight to body weight ratio with a greater increase in cardiomyocytes size, a greater decline in left ventricular contractility, and higher reactivation of fetal genes. MRcKO mice showed a comparable degree of cardiac remodeling compared to control (MR f/f ) mice. The worse cardiac remodeling in pressure overloaded GRcKO mice is not due to compensatory activation of cardiomyocyte MR, since pressure overloaded GRMRdcKO mice displayed cardiac remodeling to the same extent as GRcKO mice. Pressure overload suppressed GR-target gene expression in the heart. Although plasma corticosterone levels and subcellular localization of GR (nuclear/cytoplasmic GR) were not changed, a chromatin immunoprecipitation assay revealed that GR recruitment onto the promoter of GR-target genes was significantly suppressed in response to pressure overload. Rescue of the expression of GR-target genes to the same extent as sham-operated hearts attenuated adverse cardiac remodeling in pressure-overloaded hearts. Thus, GR works as a repressor of adverse cardiac remodeling in response to pressure overload, but GR-mediated transcription is suppressed under pressure overload. Therapies that maintain GR-mediated transcription in cardiomyocytes under pressure overload can be a promising therapeutic strategy for heart failure.

© 2018 The Authors. Background Brugada syndrome (BS) is known to be 9 times more prevalent in males than females. However, little is known about the development of sick sinus syndrome in female members with familial BS. Methods and Results Familial BS patients and family members, both from our institutions and collaborating sites that specialize in clinical care of BS, participated in this study. We collected information on their clinical and genetic background, along with the inheritance patterns of BS. Detailed information on each case with familial BS is described. A total of 7 families, including 25 BS patients (12 females and 13 males), were included. Seven were probands and 18 were family members. Ten out of the 12 female patients and none of the 13 male patients developed sick sinus syndrome. Sudden death or spontaneous ventricular fibrillation occurred in 7 out of 13 male patients and 2 out of 12 female patients. Conclusions Familial BS existed in which female patients developed sick sinus syndrome but male patients did not. Some of those female patients with sick sinus syndrome had unrecognized BS. Information should be collected not only regarding a family history of sudden death or BS, but also whether a pacemaker was implanted in female members.

© 2019 Elsevier Ltd Background: The fatty acid (FA)composition of membrane phospholipid reflects at least in part dietary fat composition. Saturated FA (SFA)suppress Sirt1 activity, while monounsaturated FA (MUFA)counteract this effect. Objective: We explored a role of Sirt1 in homeostatic control of the fatty acid composition of membrane phospholipid in the presence of SFA overload. Methods and results: Sirt1 deficiency in cardiomyocytes decreased the expression levels of liver X receptor (LXR)-target genes, particularly stearoyl-CoA desaturase-1 (Scd1), a rate-limiting enzyme in the cellular synthesis of MUFA from SFA, increased membrane SFA/MUFA ratio, and worsened left ventricular (LV)diastolic function in mice fed an SFA-rich high fat diet. In cultured cardiomyocytes, Sirt1 knockdown (KD)exacerbated the palmitate overload-induced increase in membrane SFA/MUFA ratio, which was associated with decrease in the expression of LXR-target genes, including Scd1. Forced overexpression of Scd1 in palmitate-overloaded Sirt1KD cardiomyocytes lowered the SFA/MUFA ratio. Nicotinamide mononucleotide (NMN)increased Sirt1 activity and Scd1 expression, thereby lowering membrane SFA/MUFA ratio in palmitate-overloaded cardiomyocytes. These effects of NMN were not observed for Scd1KD cardiomyocytes. LXRα/βKD exacerbated palmitate overload-induced increase in membrane SFA/MUFA ratio, while LXR agonist T0901317 alleviated it. NMN failed to rescue Scd1 protein expression and membrane SFA/MUFA ratio in palmitate-overloaded LXRα/βKD cardiomyocytes. The administration of NMN or T0901317 showed a dramatic reversal in membrane SFA/MUFA ratio and LV diastolic function in SFA-rich HFD-fed mice. Conclusion: Cardiac Sirt1 counteracted SFA overload-induced decrease in membrane phospholipid unsaturation and diastolic dysfunction via regulating LXR-mediated transcription of the Scd1 gene.

© 2020 Canadian Cardiovascular Society Standard aortic valve replacement for aortic regurgitation caused by Behçet disease (BD) is frequently complicated by postoperative recurrent prosthetic valve detachment. Tumour necrosis factor (TNF) α is known to be associated with higher inflammation activities. Therefore, the concomitant use of immunomodulatory agents with TNFα inhibitors may be the key to a better outcome. This is a case report of a 46-year-old woman with severe acute aortic regurgitation due to BD. Immunosuppressive therapy including the TNFα inhibitor infliximab, which has not been reported for perioperative use to date, resulted in the prompt remission of inflammation, leading to the success of Bentall surgery.

© 2020, Springer Japan KK, part of Springer Nature. Atrial fibrillation (AF) is known to aggregate within family and might be associated with a lower quality-of-life (QoL). We evaluated the association between a family history (FHx) of AF and patient-reported symptom burden and perception towards treatment. We performed a retrospective analysis in a cohort of 1285 newly diagnosed patients with AF. Patients completed the atrial fibrillation effect on quality of life (AFEQT) questionnaire at the time of registration and at the 1-year follow-up. Patients who had a first-degree relative with AF were classified into the FHx group. Baseline characteristics and AFEQT scores were compared between groups, and a multivariate analysis was used to evaluate the independent association between FHx and QoL. Overall, 15.9% of patients (n = 204) had a positive AF FHx. Compared to the non-FHx group, the FHx group had an earlier onset of AF (60.2 ± 12.0 years vs. 64.5 ± 12.1 years; P < 0.05) and lower AFEQT overall summary (AFEQT-OS) score at baseline (73.9 ± 17.8 vs. 77.0 ± 16.8; P < 0.05). After adjustment for clinical background, a positive FHx was independently associated with a worse QoL (changes in AFEQT-OS score = − 3.18; 95% confidence interval: − 5.67 to − 0.69; P = 0.012). No between-group difference in AFEQT-OS scores was noted at the 1-year follow-up. An FHx of AF was associated with a lower QoL, which could be improved by therapeutic intervention in patients with AF. Recognizing the presence of an FHx of AF is important to predict patient’s symptom load and treatment acceptance.

© 2020 Elsevier Inc. Background: Rhythm-control strategy, including catheter ablation (CA) application, constitutes an integral part of atrial fibrillation (AF) management. However, elderly patients are underrepresented in clinical trials, and reports on patient-reported outcome of various rhythm-control treatments remain limited. Therefore, we aimed to investigate the application of a rhythm-control strategy for elderly patients with AF. Methods: Using a prospective, multicenter Japanese registry, we analyzed 733 patients with AF aged ≥70 years who completed the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire at baseline and 1-year visit. Improvement in patient-reported quality-of-life (QOL) was assessed according to their initial treatment strategy. Results: A total of 321 patients (43.8%) were managed with rhythm-control strategy, of which 125 (17.1%) received treatment with antiarrhythmic drugs (AADs) alone and 196 (26.7%) underwent CA. Compared with the rate-control group, the rhythm-control group was younger and less likely to have comorbid conditions but had lower baseline AFEQT-overall summary (OS) scores (71.8 [standard deviation 20.3] vs. 80.0 [standard deviation 16.1]; P < .001). After the first year, AFEQT-OS scores improved regardless of treatment strategies (ie, rate- or rhythm-control). After adjusting for confounders, CA implementation and a lower baseline AFEQT score were associated with meaningful improvement in QOL (changes in AFEQT-OS score ≥5). QOL improvement among subgroups of rhythm-control patients with AADs alone was not clinically meaningful. Conclusions: In contemporary Japanese clinical practice, rhythm-control strategy is widely implemented in elderly patients with AF, and CA use is associated with improvement in QOL in carefully selected patients.

© 2020 Wiley Periodicals LLC Introduction: An electrical superior vena cava (SVC) isolation from the right atrium (RA) sometimes can be challenging. For a safe and efficient SVC isolation, we aimed to visualize the accurate position of the SVC-RA junction on a three-dimensional (3D) mapping system using the decremental conduction properties of the SVC-RA junction in patients with atrial fibrillation (AF). Methods: This study consisted of 15 consecutive AF patients (11 males, age 59 ± 10 years). A 3D mapping catheter was positioned in the SVC-RA junction region while delivering a single extra-stimulus from the right atrial appendage (RAA), to discriminate the RA and SVC potentials. The electrophysiological SVC-RA junction was defined as the most proximal points where the SVC potentials were recorded, which were tagged on the 3D mapping system around the SVC-RA junction, where radiofrequency energy applications were applied. Results: Around the SVC-RA junction, 9 ± 2 points were tagged on the 3D mapping system. The highest and lowest SVC-RA junction points were located on the anterior wall and posterior wall, respectively. The difference in the level between the highest and lowest SVC-RA junction points was 16.2 ± 6.3 mm. A successful SVC isolation was obtained in all patients without any complications. Conclusion: The plane of the electrophysiologically defined SVC-RA junction was not perpendicular to the body axis, but slanted due to the anterior side being higher. Recognizing the precise location of the SVC-RA junction would contribute to a safe and efficacious SVC isolation.

Background: Hydrogen gas inhalation (HI) reduced infarct size and mitigated adverse left ventricular (LV) remodeling in a rat model of acute myocardial infarction (AMI). We designed a prospective, open-label, rater-blinded clinical pilot study in patients experiencing ST-elevated MI (STEMI). Methods and Results: The 20 patients with an initial diagnosis of STEMI were assigned to either an HI group (1.3% H2 with 26% oxygen) or a control group (26% oxygen). There were no HI-related severe adverse events. In the full analysis set, the cardiac salvage index as evaluated using cardiac magnetic resonance imaging at 7 days after primary percutaneous coronary intervention (PCI), showed no significant between-group difference (HI: 50.0±24.3%; control: 60.1±20.1%; P=0.43). However, the improvement from day 7 in the HI group was numerically greater than that in the control group in some of the surrogate outcomes at 6-month follow-up, including the LV stroke volume index (HI: 9.2±7.1 mL/m2; control: -1.4±7.2 mL/m2; P=0.03) and the LV ejection fraction (HI: 11.0%±9.3%; control: 1.7%±8.3%; P=0.11). Conclusions: The first clinical study has shown that HI during PCI is feasible and safe and may also promote LV reverse remodeling at 6 months after STEMI. The study was not powered to test efficacy and a further large-scale trial is warranted. (Clinical trials registration: UMIN00006825).

Performance measures (PMs) are used to accelerate translation of scientific evidence into clinical practice. However, it remains unknown how they are applied in the real world and whether the compliance to these metrics will lead to improved patient's outcome in atrial fibrillation (AF). Within the Japanese multicenter AF registry (n = 1,874), adherence of the AF PMs (based on 2016 American Heart Association/American College of Cardiology criteria) and its association with quality of life scaling and clinical outcomes was evaluated. The patient was deemed "adherent" when all applicable components of the PMs for outpatient settings (CHA2DS2-VASc risk score documentation [PM-4], anticoagulation prescribed [PM-5], and monthly international normalized ratio (INR) for warfarin treatment [PM-6]) were satisfied. The Atrial Fibrillation Effect on Quality of Life (AFEQT) questionnaire was assessed at baseline and 1 year. About a half of patients (46.1%) were adherent to the AF PMs. PMs were more frequently achieved in patients managed with rhythm control compared with rate control. The achievement rate for each component was 53.9% for PM-4, 85.6% for PM-5, and 90.3% for PM-6, respectively. Although AFEQT global scores at baseline were similar (median 79.2 [interquartile ranges 66.7 to 88.5] vs 77.1 [64.8 to 88.0], p = 0.227), AFEQT global scores at 1-year follow-up were significantly greater in adherence group than those in nonadherence group (89.2 [78.5 to 96.6] vs 86.7 [76.7 to 95.0], p = 0.021). This tendency was consistent regardless of therapeutic strategies. There remains an important opportunity to improve the quality of care in patients with AF. Adherence to the AF PMs might lead to the improvement of patient's quality of life.

Obesity promotes excessive inflammation, which is associated with senescence-like changes in visceral adipose tissue (VAT) and the development of type 2 diabetes (T2DM) and cardiovascular diseases. We have reported that a unique population of CD44hi CD62Llo CD4+ T cells that constitutively express PD-1 and CD153 exhibit cellular senescence and cause VAT inflammation by producing large amounts of osteopontin. Weight loss improves glycemic control and reduces cardiovascular disease risk factors, but its long-term effects on cardiovascular events and longevity in obese individuals with T2DM are somewhat disappointing and not well understood. High-fat diet (HFD)-fed obese mice were subjected to weight reduction through a switch to a control diet. They lost body weight and visceral fat mass, reaching the same levels as lean mice fed a control diet. However, the VAT of weight reduction mice exhibited denser infiltration of macrophages, which formed more crown-like structures compared to the VAT of obese mice kept on the HFD. Mechanistically, CD153+ PD-1+ CD4+ T cells are long-lived and not easily eliminated, even after weight reduction. Their continued presence maintains a self-sustaining chronic inflammatory loop via production of large amounts of osteopontin. Thus, we concluded that T-cell senescence is essentially a negative legacy effect of obesity.

Chronic inflammation in visceral adipose tissue (VAT) precipitates the development of cardiometabolic disorders. Although changes in T cell function associated with visceral obesity are thought to affect chronic VAT inflammation, the specific features of these changes remain elusive. Here, we have determined that a high-fat diet (HFD) caused a preferential increase and accumulation of CD44hiCD62LloCD4+ T cells that constitutively express PD-1 and CD153 in a B cell-dependent manner in VAT. These cells possessed characteristics of cellular senescence and showed a strong activation of Spp1 (encoding osteopontin [OPN]) in VAT. Upon T cell receptor stimulation, these T cells also produced large amounts of OPN in a PD-1-resistant manner in vitro. The features of CD153+PD-1+CD44hiCD4+ T cells were highly reminiscent of senescence-associated CD4+ T cells that normally increase with age. Adoptive transfer of CD153+PD-1+CD44hiCD4+ T cells from HFD-fed WT, but not Spp1-deficient, mice into the VAT of lean mice fed a normal diet recapitulated the essential features of VAT inflammation and insulin resistance. Our results demonstrate that a distinct CD153+PD-1+CD44hiCD4+ T cell population that accumulates in the VAT of HFD-fed obese mice causes VAT inflammation by producing large amounts of OPN. This finding suggests a link between visceral adiposity and immune aging.