Clinical characterization of type 1 long QT syndrome caused by C-terminus Kv7.1 variants

BACKGROUND

Variants in the KCNQ1 gene, encoding the α-subunit of the slow component of delayed rectifier K+ channel Kv7.1, cause long QT syndrome (LQTS) type 1. The location of variants may be one of the factors in determining prognosis. However, detailed genotype-phenotype relationships associated with C-terminus variants remain unelucidated.

OBJECTIVE

We investigated the clinical characteristics and variant-specific arrhythmic risks in patients with LQTS carrying Kv7.1 C-terminus variants.

METHODS

The study comprises 202 consecutive patients with LQTS (98 probands and 104 family members) who carry a rare heterozygous variant in the Kv7.1 C-terminus. Their clinical characteristics and arrhythmic events were investigated.

RESULTS

We identified 36 unique C-terminus variants (25 missense and 11 non-missense). The p.R366W variant was identified in 8 families, and p.T587M was identified in 21 families in large numbers from northwestern Japan. As for the location of the variant, we found that the variants in highly conserved regions and nonhelical domains were associated with longer QTc intervals compared with the variants in other regions. Both p.R366W and p.T587M variants are located in the highly conserved and functionally pivotal regions close to helices A and D, which are associated with calmodulin binding and channel assembly (tetramerization), respectively. The probands carrying p.T587M and p.R366W variants had worse arrhythmia outcomes compared with those with other C-terminus variants. The haplotype analysis of p.T587M families was suggestive of a founder effect.

CONCLUSION

The arrhythmic risk of C-terminus variants in Kv7.1 in LQTS is not homogeneous, and locations of variants can be a determining factor for prognosis.

High-Fat Diet-Induced Diabetic Conditions Exacerbate Cognitive Impairment in a Mouse Model of Alzheimer's Disease Via a Specific Tau Phosphorylation Pattern

BACKGROUND

Epidemiological evidence has demonstrated a clear association between diabetes mellitus and increased risk of Alzheimer's disease (AD). Cerebral accumulation of phosphorylated tau aggregates, a cardinal neuropathological feature of AD, is associated with neurodegeneration and cognitive decline. Clinical and experimental studies indicate that diabetes mellitus affects the development of tau pathology; however, the underlying molecular mechanisms remain unknown.

OBJECTIVE

In the present study, we used a unique diabetic AD mouse model to investigate the changes in tau phosphorylation patterns occurring in the diabetic brain.

DESIGN

Tau-transgenic mice were fed a high-fat diet (n = 24) to model diabetes mellitus. These mice developed prominent obesity, severe insulin resistance, and mild hyperglycemia, which led to early-onset neurodegeneration and behavioral impairment associated with the accumulation of hyperphosphorylated tau aggregates.

RESULTS

Comprehensive phosphoproteomic analysis revealed a unique tau phosphorylation signature in the brains of mice with diabetic AD. Bioinformatic analysis of the phosphoproteomics data revealed putative tau-related kinases and cell signaling pathways involved in the interaction between diabetes mellitus and AD.

CONCLUSION

These findings offer potential novel targets that can be used to develop tau-based therapies and biomarkers for use in AD.

Postmortem genetic analysis of 17 sudden cardiac deaths identified nonsense and frameshift variants in two cases of arrhythmogenic cardiomyopathy

Sudden death, or unexpected natural death of a healthy individual, is a serious problem in all nations. Sudden cardiac death (SCD) mainly due to ischemic heart diseases is the top cause of sudden death. However, there are pathophysiological conditions, referred to as sudden arrhythmic death syndrome, in which no apparent lesion can be identified even after complete conventional or ordinary autopsy. While postmortem genetic analyses have accumulated evidence about underlying genetic abnormality in such cases, the precise relationships between genetic background and the phenotype have been largely elusive. In this study, a retrospective investigation of 17 autopsy cases in which lethal arrhythmia was suspected to be the cause of death was carried out. Genetic analysis focusing on 72 genes reported to be associated with cardiac dysfunctions was performed, in combination with detailed histopathological and postmortem imaging examination, and a family study. As a result, in two cases of suspected arrhythmogenic cardiomyopathy (ACM), we found a nonsense variant in PKP2 and frameshift variant in TRPM4 gene. In contrast, the other 15 cases showed no morphological changes in the heart despite the presence of a frameshift variant and several missense variants, leaving the clinical significance of these variants obscure. The findings of the present study suggest that nonsense and frameshift variants could be involved in the morphological abnormality in cases of SCD due to ACM, while missense variants alone rarely contribute to massive structural changes in the heart.

Mechanisms of fever-induced QT prolongation and torsades de pointes in patients with KCNH2 mutation

AIMS

Patients with particular mutations of type-2 long QT syndrome (LQT2) are at an increased risk for malignant arrhythmia during fever. This study aimed to determine the mechanism by which KCNH2 mutations cause fever-induced QT prolongation and torsades de pointes (TdP).

METHODS AND RESULTS

We evaluated three KCNH2 mutations, G584S, D609G, and T613M, in the Kv11.1 S5-pore region, identified in patients with marked QT prolongation and TdP during fever. We also evaluated KCNH2 M124T and R269W, which are not associated with fever-induced QT prolongation. We characterized the temperature-dependent changes in the electrophysiological properties of the mutant Kv11.1 channels by patch-clamp recording and computer simulation. The average tail current densities (TCDs) at 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller and less increased with rising temperature from 35°C to 40°C than those for WT, M124T, and R269W. The ratios of the TCDs at 40°C to 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller than for WT, M124T, and R269W. The voltage dependence of the steady-state inactivation curve for WT, M124T, and R269W showed a significant positive shift with increasing temperature; however, that for G584S, WT+D609G, and WT+T613M showed no significant change. Computer simulation demonstrated that G584S, WT+D609G, and WT+T613M caused prolonged action potential durations and early afterdepolarization formation at 40°C.

CONCLUSION

These findings indicate that KCNH2 G584S, D609G, and T613M in the S5-pore region reduce the temperature-dependent increase in TCDs through an enhanced inactivation, resulting in QT prolongation and TdP at a febrile state in patients with LQT2.

Targeted deep sequencing analyses of long QT syndrome in a Japanese population

Long QT syndrome (LQTS) is one of the most common inherited arrhythmias and multiple genes have been reported as causative. Presently, genetic diagnosis for LQTS patients is becoming widespread and contributing to implementation of therapies. However, causative genetic mutations cannot be detected in about 20% of patients. To elucidate additional genetic mutations in LQTS, we performed deep-sequencing of previously reported 15 causative and 85 candidate genes for this disorder in 556 Japanese LQTS patients. We performed in-silico filtering of the sequencing data and found 48 novel variants in 33 genes of 53 cases. These variants were predicted to be damaging to coding proteins or to alter the binding affinity of several transcription factors. Notably, we found that most of the LQTS-related variants in the RYR2 gene were in the large cytoplasmic domain of the N-terminus side. They might be useful for screening of LQTS patients who had no known genetic factors. In addition, when the mechanisms of these variants in the development of LQTS are revealed, it will be useful for early diagnosis, risk stratification, and selection of treatment.

Electrophysiological characteristics and catheter ablation of atypical fast-slow atrioventricular nodal reentrant tachycardia using an inferolateral left atrial slow pathway

Background

Understandings of subtypes of atypical atrioventricular nodal reentrant tachycardia (AVNRT) using variants of slow pathway (SP) are still growing. Inferolateral (inf-lat-) left atrial (LA) SP is a rare variant extending into an inf-lat-LA along the mitral annulus (MA).

Purpose

To characterize an unknown subtype of atypical fast-slow (F/S-) AVNRT using an inf-lat-LA-SP as a retrograde limb (inf-lat-LA-F/S-AVNRT).

Methods

This Japanese multicenter retrospective study enrolled 4 patients of inf-lat-LA-F/S-AVNRT that was characterized by the earliest site of atrial activation during tachycardia (EAA) between 3 and 6 o'clock along the MA. The diagnosis was made by an exclusion of AV reentrant tachycardia (AVRT) and atrial tachycardia (AT) according to the standard criteria and was confirmed by successful elimination of tachycardia and the inf-lat-LA-SP.

Results

Surface ECG during tachycardia revealed long RP appearance except one who had short RP due to a short conduction time across the inf-lat-LA-SP. During tachycardia, far-field LA activation preceding near-field activation of coronary sinus (CS) musculature was visible in the CS recording in 2. Retrograde conduction via the inf-lat-LA-SP with a decremental delay was consistently reproducible with ventricular stimulation in 2, 1 of whom had double atrial response, while it was always masked by the presence of a retrograde conduction via the fast pathway in 1 and a retrograde block at the lower common pathway in 1. An injection of a small dose of ATP transiently interrupted a retrograde conduction over the inf-lat-LA-SP, suggesting its ATP-sensitivity. Exclusion of AVRT was made by no resetting of tachycardia with left ventricular extrastimulus in 2 and VA dissociation during overdrive pacing of tachycardia in remaining 2. Exclusion of AT was made by V-A-V response after ventricular entrainment in 1 and termination without atrial capture by ventricular pacing in 2. Ablation of the right-sided SP was unsuccessful to eliminate the tachycardia, but ablation at or near the EAA by transseptal approach was successful to cure the tachycardia, associated with an elimination of a retrograde conduction over the inf-lat-LA-SP following a development of an accelerated junction rhythm in all. Low-frequency potentials preceding local atrial activation, consistent with a retrograde activation via the inf-lat-LA-SP were detected along the MA medial to the EAA in 1.

Conclusions

Differential diagnosis of tachycardia with the EAA in the inf-lat-LA and especially long RP appearance should include inf-lat-LA-F/S-AVNRT. Presumed arrhythmogenic substrate of the inf-lat-LA-SP seemed to be consistent with the remnant of embryogenic AV ring tissue in the electropharmacological and locational characteristics. Successful elimination of this AVNRT can be obtained by ablation of the inf-lat-LA-SP, but not of the right-sided SP.

Funding Acknowledgement

Type of funding sources: None.

Novel CACNA1C R511Q mutation, located in domain Ⅰ-Ⅱ linker, causes non-syndromic type-8 long QT syndrome

Background

Gain-of-function mutations in CACNA1C encoding Cav1.2 cause syndromic or non-syndromic type-8 long QT syndrome (LQTS) (sLQT8 or nsLQT8). The cytoplasmic domain (D)Ⅰ-Ⅱ linker in Cav1.2 plays a pivotal role in calcium channel inactivation, and mutations in this site have been associated with sLQT8 (such as Timothy syndrome) but not nsLQT8.

Objective

Since we identified a novel CACNA1C mutation, located in the DⅠ-Ⅱ linker, associated with nsLQTS, we sought to reveal its biophysical defects.

Methods

Target panel sequencing was employed in 24 genotype-negative nsLQTS probands (after Sanger sequencing) and three family members. Wild-type (WT) or R511Q Cav1.2 was transiently expressed in tsA201 cells, then whole-cell Ca²⁺ or Ba²⁺ currents (I_Ca or I_Ba) were recorded using whole-cell patch-clamp techniques.

Results

We identified two CACNA1C mutations, a previously reported R858H mutation and a novel R511Q mutation located in the DⅠ-Ⅱ linker. Four members of one nsLQTS family harbored the CACNA1C R511Q mutation. The current density and steady-state activation were comparable to those of WT-I_Ca. However, persistent currents in R511Q-I_Ca were significantly larger than those of WT-I_Ca (WT at +20 mV: 3.3±0.3%, R511Q: 10.8±0.8%, P<0.01). The steady-state inactivation of R511Q-I_Ca was weak in comparison to that of WT-I_Ca at higher prepulse potentials, resulting in increased window currents in R511Q-I_Ca. Slow component of inactivation of R511Q-I_Ca was significantly delayed compared to that of WT-I_Ca (WT-tau at +20 mV: 81.3±3.3 ms, R511Q-tau: 125.1±5.0 ms, P<0.01). Inactivation of R511Q-I_Ba was still slower than that of WT-I_Ba, indicating that voltage-dependent inactivation (VDI) of R511Q-I_Ca was predominantly delayed.

Conclusions

Delayed VDI, increased persistent currents, and increased window currents of R511Q-I_Ca cause nsLQT8. Our data provide novel insights into the structure-function relationships of Cav1.2 and the pathophysiological roles of the DⅠ-Ⅱ linker in phenotypic manifestations.

Discrimination of atypical atrioventricular nodal reentrant tachycardia from atrial tachycardia by the V-A-A-V response

INTRODUCTION

The electrophysiological discrimination between fast-slow (F/S-) atrioventricular (AV) nodal reentrant tachycardia (NRT) and atrial tachycardia (AT) originating from the interatrial septum remains challenging. While a V-A-A-V response may occur immediately after ventricular induction or entrainment of either tachycardia, the electrophysiological dissimilarities in that response between the two tachycardias remain unclear. The purpose of this study was to identify a diagnostic indicator discriminating F/S-AVNRT from AT by examining the difference in the V-A-A-V response between the two tachycardias.

METHODS

This retrospective study included 17 patients with F/S-AVNRT [7 with common-form F/S-AVNRT using a typical slow pathway (SP) and 10 with superior type F/S-AVNRT using a superior SP] and 10 patients with reentrant AT. All 27 patients presented with long RP supraventricular tachycardia and an initial V-A-A-V response upon ventricular induction or entrainment. The V-A-A-V response in patients with F/S-AVNRT was due to dual atrial responses. We measured the interval between the first (A1) and second atrial electrogram (A2) of V-A-A-V and calculated ΔAA by subtracting A1-A2 from the tachycardia cycle length.

RESULTS

V-A-A-V responses were observed most often upon ventricular induction of F/S-AVNRT (6±5 times) as well as AT (6±6 times; P = 0.87). The V-A-A-V response upon ventricular entrainment was observed in a single patient with F/S-AVNRT versus 10 all patients with AT (P<0.001). ΔAA ranged between -80 and 228 ms in F/S-AVNRT and between -184 and 26 ms in AT. A ΔAA >26 ms predicted a diagnosis of F/S-AVNRT with a 76% sensitivity and 100% specificity, while a ΔAA ←80 ms predicted a diagnosis of AT with a 50% sensitivity and 100% specificity.

CONCLUSIONS

ΔAA is a useful, confirmatory, diagnostic indicator of F/S-AVNRT versus AT associated with the V-A-A-V response. This article is protected by copyright. All rights reserved.

VULCANIZATION FOR REINFORCEMENT OF RUBBER

Sulfur cross-linking reagents play critical roles not only in cross-linking rubber chains but also in controlling network morphology for reinforcement of rubber. Zinc oxide (ZnO) is clearly discovered as the main component for both roles. Especially, the importance of network inhomogeneity, which is significantly governed by the dispersion of ZnO particles, is emphasized for reinforcing rubber materials. Specifically, the formation of network domains and their continuous structures is discussed by combining the mechanical properties of the vulcanizates from the viewpoint of the reinforcement effect of rubber. Two continuous structures of network domains are termed as the network-domain cluster and network-domain network, which are observed by atomic force microscopy. The ZnO particles play a role as template for the formation of the continuous structures of network domains. The findings provide us with a practical hint for producing high-performance rubber materials.

Therapeutic Potential of Vortioxetine for Anhedonia-Like Symptoms in Depression: A Post Hoc Analysis of Data from a Clinical Trial Conducted in Japan

AIM

Anhedonia in major depressive disorder may be resistant to first-line antidepressants. We examined the effect of vortioxetine, a multimodal antidepressant, on anhedonia-like symptoms in Japanese patients with major depressive disorder.

METHODS

This was a post hoc analysis of an 8-week, randomized, double-blind, placebo-controlled, phase 3 study of vortioxetine (10 mg or 20 mg) in Japanese patients aged 20-75 years with recurrent major depressive disorder and a Montgomery-Åsberg Depression Rating Scale (MADRS) total score of at least 26. The primary outcome was the mean change from baseline to week 8 in anhedonia-like symptoms as measured by MADRS anhedonia factor score, composed of: Q1, apparent sadness; Q2, reported sadness; Q6, concentration; Q7, lassitude; and Q8, inability to feel. Mean change in MADRS total score and anhedonia factor score were compared among treatment groups, with data categorized by median baseline anhedonia factor score (0-17 or ≥18).

RESULTS

Data were available for 489 patients. The least-squares mean difference in MADRS anhedonia factor score change from baseline to week 8 versus placebo was -1.34 for vortioxetine 10 mg (P = 0.0300) and -1.77 for vortioxetine 20 mg (P = 0.0044). The least-squares mean difference between vortioxetine and placebo in MADRS total score change from baseline to week 8 was -3.11 (10 mg dose) and -3.37 (20 mg dose) for patients with a higher baseline anhedonia factor score (≥18), and -2.08 (10 mg) and -2.61 (20 mg) for patients with a lower baseline score (0-17).

CONCLUSION

This post hoc analysis suggests that vortioxetine may have therapeutic potential in patients with anhedonia-like symptoms of major depressive disorder. ClinicalTrials.gov identifier for primary study: NCT02389816.

[Current Clinical Practice Pattern for Castration-Resistant Prostate Cancer(CRPC)in Japan]

Although various agents are reported against castration-resistant prostate cancer(CRPC), little is known about their actual clinical use in Japan. In this study, 484 patients diagnosed with CRPC during androgen-deprivation therapy were selected from Japan's leading multicenter collaborative research real-world database. The treatment details and prognosis were analyzed. It was observed that the castration treatment represented by the use of LH-RH agonists and antagonists was continued in almost all cases even after CRPC diagnosis. First-line non-castration agents for the CRPC treatment including certain novel agents approved from 2010 onwards and conventional agents used before that were selected for use in 76.5% and 23.5% of cases, respectively, with the 1-year continuation rates being 57.7%, and 52.4%, respectively. The 1.5-year overall survival rate from CRPC was 63.7%(90.0% in the conventional agents' group and 58.8% in the novel agents' group). Previously, conventional agents were sometimes selected for the CRPC treatment; hence, they still seemed to play a role in clinical practice in Japan.

Fast-slow atrioventricular nodal reentrant tachycardia phenotype mimicking the slow-slow type

Background

Fast-slow (F/S-) atrioventricular (AV) nodal reentrant tachycardia (AVNRT) is characterized by a short atrio-His (AH) interval and the earliest site of atrial activation (EAA) in the proximal coronary sinus (EAA-CS), while slow-slow (S/S-) AVNRT presents a long AH interval and EAA-CS. Those intracardiac appearances are initial indicators for making a diagnosis.

Purpose

To identify an unknown phenotype of F/S-AVNRT.

Methods

Among 46 consecutive patients with F/S-AVNRT, 6 patients (1 man, age 59±9) had an apparent but not typical (pseudo-) S/S-AVNRT during an electrophysiologic study. In 2 patients, pseudo-S/S-AVNRT was clinically documented.

Results

In all 6 patients, the diagnosis of F/S-AVNRT was made by an exclusion of atrial tachycardia with findings of 1) a V-A-V response following ventricular entrainment or 2) termination without atrial capture by ventricular pacing, and an exclusion of AV reentrant tachycardia with a ventriculoatrial dissociation during an initial (so-called QRS transition) zone of ventricular entrainment. An initial A-A-V activation sequence on atrial induction of F/S-AVNRT observed in 1 patient and Wenckebach-type AV block during ongoing F/S-AVNRT developing in 3 patients suggested the presence of the lower common pathway (LCP). Like the typical S/S-AVNRT, pseudo-S/S-AVNRT was induced with atrial stimulation after a jump in the AH interval or double ventricular response. However, in all patients, the pseudo-S/S-AVNRT transited to F/S-AVNRT following AV block in a single cycle and/or pseudo-S/S-AVNRT transited from spontaneously or triggered by atrial contractions. Importantly, on these transitions, the atrial cycle length (CL) and EAA-CS remained unchanged, that is, the atrial CL of S/S-AVNRT was almost identical to that of F/S-AVNRT, suggesting that the essential circuit of both tachycardias was identical. Actually, both tachycardias were cured by ablation at a single site in the traditional slow pathway (SP). Collectively, the pseudo-S/S-AVNRT was diagnosed as another phenotype of F/S-AVNRT accompanied by sustained antegrade conduction via another bystander (likely the left-sided or superior) SP breaking through the His bundle owing to the repetitive antegrade block at the LCP occurring by linking phenomenon, thus representing a long AH interval during the ongoing F/S-AVNRT. When the antegrade conduction is blocked at the bystander SP during the pseudo-S/S-AVNRT, releasing the linking phenomenon, the subsequent antegrade conduction reach the His-bundle via the fast pathway, thus returning to F/S-AVNRT.

Conclusions

An unknown, but not rare F/S-AVNRT phenotype exists that apparently mimics the typical S/S-AVNRT and is also an unknown subtype of apparent S/S-AVNRT. The presence of this pseudo-S/S-AVNRT suggests the limitation of classifying types of AVNRT based on AH and HA intervals during tachycardia. Understandings of this phenotype can advance a diagnosis of atypical AVNRT with multiple phenotypes.

Funding Acknowledgement

Type of funding sources: None.

Association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan: a cohort study

Background

There is an ongoing controversy regarding the necessity of single-photon emission computed tomography (SPECT) for patients with ischemic heart diseases after the publication of the results of the ISCHEMIA trial.

Purpose

We aimed to evaluate the association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan.

Methods

From the data of 2780 patients with stable angina who were enrolled prospectively between January 2006 and March 2008 in Japan and had undergone physician-referred non-invasive imaging tests, 1205 patients managed with SPECT were stratified by 10% myocardial ischemia. Major adverse cardiac events (MACEs), including death, myocardial infarction, hospitalization for heart failure, and late revascularization, were followed-up for 1 year.

Results

Patients with ≥10% myocardial ischemia (n=173) were older than patients with &lt;10% myocardial ischemia (n=1032) and had a significantly higher 1-year cumulative incidence of MACEs (9.1% vs. 1.2%, P&lt;0.0001). After adjusting for confounders, the risk of ≥10% myocardial ischemia relative to &lt;10% myocardial ischemia for MACEs remained significant (adjusted hazard ratio [95% confidence interval], 2.40 [1.09–5.26], P=0.029).

Conclusion

The presence of ≥10% myocardial ischemia was significantly associated with the 1-year risk for MACEs in Japanese patients with suspected coronary artery disease.

Funding Acknowledgement

Type of funding sources: None. Study flowchartOutcomes

Empagliflozin improves prognosis and energetic properties through modulating mitochondrial function in failing murine hearts

Background/Introduction

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been reported to have beneficial effects on heart failure in large clinical trials; however, the underlying mechanism is still unclear.

Purpose

The purpose of this study is to elucidate the mechanism of cardioprotective effect of empagliflozin in heart failure.

Methods

Eight-week-old mice deficient in cardiac and skeletal muscle-specific manganese superoxide dismutase, a mouse model of dilated cardiomyopathy (MnSOD-cKO mice), were given food mixed with or without 10 mg/kg empagliflozin for seven weeks and evaluated. Mitochondrial function in the cardiac muscle were measured by a high-resolution respirometer, Oxygraph-2K. Respiratory gas analysis were performed by indirect calorimetry (ARCO 2000) to estimate the energy consumption and energetic substrates.

Results

The survival rate (P=0.015) and cardiac fibrosis (P=0.036) were significantly improved in the empagliflozin group. The capacity of oxidative phosphorylation in cardiac mitochondria was significantly improved by empagliflozin. Blood lactate levels were decreased in the empagliflozin group, indicating that energy such as ATP could be produced without resorting to anaerobic metabolism.

Respiratory gas analysis revealed significant improvement in energy expenditure along with increase in food intake. Respiratory quotient was not different between the two groups, showing the consumption of the carbohydrate to fat rate was not changed by empagliflozin in this study. Ketone levels in blood and HbA1c were neither significantly different between the two groups. Although a moderate amount glucose was excreted in urine in the empagliflozin group (128.3±20.4 mg/day, 0.51±0.08 kcal/day), the available energy substrates in the whole body nonetheless expanded because of the increased caloric intake (10.58±0.72 in control group vs. 13.55±0.08 kcal/day in empagliflozin group, P=0.018).

Conclusion(s)

We have shown that empagliflozin improved myocardial mitochondrial function and increased energy metabolism, which was accompanied by adequate energy intake and uptake, even in heart failure. Empagliflozin decreased myocardial fibrosis and improved prognosis in failing murine hearts through positive energetical properties including mitochondrial function. The finding that empagliflozin modulates cardiac metabolism in a positive way provides a novel mechanism for the cardioprotective effect of SGLT2 inhibitors in heart failure.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boehringer Ingelheim Empa improved prognosis in HFEmpa improved mitochondrial function

Pacing site- and rate-dependent shortening of retrograde conduction time over the slow pathway after atrial entrainment of fast-slow atrioventricular nodal reentrant tachycardia

Introduction

We tested our hypothesis that atrial entrainment pacing (EP) of a) the common‐type (com‐) fast‐slow (F/S‐) atypical atrioventricular nodal reentrant tachycardia (AVNRT) using a typical slow pathway (SP), or b) the superior‐type (sup‐) F/S‐AVNRT using a superior SP, both modify the retrograde conduction time across the SP immediately after termination of EP (retro‐SP‐time).

Methods

We measured the difference in the His‐atrial interval (HA difference) immediately after cessation of EP, performed at 2 ± 2 rates from the high right atrium (HA[1]‐HRA) versus from the proximal coronary sinus (HA[1]‐CS) in 17 patients with com‐F/S‐AVNRT and 11 patients with sup‐F/S‐AVNRT. We also measured the atrial‐His and HA intervals of the first and second cycles immediately after cessation of EP and during stable tachycardia.

Results

Unequal responses, defined as a ≥ 20‐ms HA difference at ≥1 EP rates, were observed in 16 patients (57%), including 7 with com‐ and 9 with sup‐F/S‐AVNRT. Irrespective of the EP rate, all unequal responses of com‐F/S‐AVNRT were due to a shorter HA[1]‐CS than HA[1]‐HRA, with a mean 34 ± 11 ms HA difference, whereas all unequal responses of sup‐F/S‐AVNRT were due to a longer HA[1]‐CS than HA[1]‐HRA, with a mean 49 ± 25 ms HA difference. The unequal responses resolved within two cycles after the cessation of EP.

Conclusions

We have identified a little‐known pacing site‐ and pacing rate‐dependent shortening of the retro‐SP‐time.

Functionally validated SCN5A variants allow interpretation of pathogenicity and prediction of lethal events in Brugada syndrome

AIMS

The prognostic value of genetic variants for predicting lethal arrhythmic events (LAEs) in Brugada syndrome (BrS) remains controversial. We investigated whether the functional curation of SCN5A variations improves prognostic predictability.

METHODS AND RESULTS

Using a heterologous expression system and whole-cell patch clamping, we functionally characterized 22 variants of unknown significance (VUSs) among 55 SCN5A mutations previously curated using in silico prediction algorithms in the Japanese BrS registry (n = 415). According to the loss-of-function (LOF) properties, SCN5A mutation carriers (n = 60) were divided into two groups: LOF-SCN5A mutations and non-LOF SCN5A variations. Functionally proven LOF-SCN5A mutation carriers (n = 45) showed significantly severer electrocardiographic conduction abnormalities and worse prognosis associated with earlier manifestations of LAEs (7.9%/year) than in silico algorithm-predicted SCN5A carriers (5.1%/year) or all BrS probands (2.5%/year). Notably, non-LOF SCN5A variation carriers (n = 15) exhibited no LAEs during the follow-up period. Multivariate analysis demonstrated that only LOF-SCN5A mutations and a history of aborted cardiac arrest were significant predictors of LAEs. Gene-based association studies using whole-exome sequencing data on another independent SCN5A mutation-negative BrS cohort (n = 288) showed no significant enrichment of rare variants in 16 985 genes including 22 non-SCN5A BrS-associated genes as compared with controls (n = 372). Furthermore, rare variations of non-SCN5A BrS-associated genes did not affect LAE-free survival curves.

CONCLUSION

In vitro functional validation is key to classifying the pathogenicity of SCN5A VUSs and for risk stratification of genetic predictors of LAEs. Functionally proven LOF-SCN5A mutations are genetic burdens of sudden death in BrS, but evidence for other BrS-associated genes is elusive.

Preparation and Readout of Multielectron High-Spin States in a Gate-Defined GaAs/AlGaAs Quantum Dot

We report the preparation and readout of multielectron high-spin states, a three-electron quartet, and a four-electron quintet, in a gate-defined GaAs/AlGaAs single quantum dot using spin filtering by quantum Hall edge states coupled to the dot. The readout scheme consists of mapping from multielectron to two-electron spin states and a subsequent two-electron spin readout, thus obviating the need to resolve dense multielectron energy levels. Using this technique, we measure the relaxations of the high-spin states and find them to be an order of magnitude faster than those of low-spin states. Numerical calculations of spin relaxation rates using the exact diagonalization method agree with the experiment. The technique developed here offers a new tool for the study and application of high-spin states in quantum dots.

A Claims-Based Cohort Study on the Treatment Patterns of Japanese Patients with Type 2 Diabetes Mellitus and the Association of Early First Physician Visit with Time to Prescription of Oral Hypoglycemic Agents

INTRODUCTION

This study aimed to investigate the relationships between timing of the first physician visit after detection of an abnormal glycated hemoglobin (HbA1c) value at routine annual check and the time to antidiabetic treatment prescription; and understand treatment patterns in patients newly diagnosed with type 2 diabetes mellitus (T2DM).

METHODS

This retrospective, longitudinal, observational cohort study examined data from JMDC Inc., an administrative claims database. Patients with HbA1c value of at least 6.5% at routine annual check, aged 20 years or older, and prescribed at least one antidiabetic drug were included. This cohort was classified into early physician visit and delayed physician visit groups based on the timing of the first physician visit relative to the median. Patients were monitored from the date of first HbA1c checkup of at least 6.5% to the date of first physician visit with an HbA1c test, and from the date of the first physician visit to the date of prescription of first-line and second-line T2DM treatments. The time to first prescription of antidiabetic treatment for the two groups was then compared.

RESULTS

Of 4798 eligible patients, 54.8% were prescribed first-line T2DM therapy less than 2 months from the first physician visit for T2DM diagnosis. A lower percentage of the early group compared with the delayed group required T2DM pharmacological therapy in less than 2 months (46.1% vs. 63.4%). The early group had a longer median time to prescription of first-line therapy [92 days vs. 15 days, p < 0.0001; hazard ratio (HR) 1.31, 95% confidence interval (CI) 1.24, 1.39] and second-line therapy (1599 days vs. 1315 days, p < 0.0001; HR 1.22, 95% CI 1.11, 1.34) compared with the delayed group.

CONCLUSION

In Japanese patients with T2DM, early physician visit after abnormal HbA1c detection at routine annual check is associated with a longer period before T2DM medication requirement, and may improve disease course.

POS1487-HPR NEXT-GENERATION ONLINE TELEMEDICINE SYSTEM UTILIZING MIXED REALITY FOR RHEUMATOID ARTHRITIS

Background:

Telemedicine can be performed using a conventional videophone or web conferencing system. Then, joint lesions can only be observed and inferred from two-dimensional images, and it is difficult to perform accurate joint assessments, which is essential for the management of rheumatoid arthritis (RA).

Objectives:

To develop the next-generation online telemedicine system utilizing mixed reality for RA.

Methods:

We have developed a system that can assess joints accurately in three-dimensions images in real-time, using Azure Kinect DK (depth sensor)/ HoloLens 2 (headset), which are mixed reality technologies, and Teams (online interview/chat) provided by Microsoft. Furthermore, by applying artificial intelligence (AI), we plan to implement additionally to this system 1) a function to quickly catch and automatically evaluate the patient’s anxiety and changes in facial expressions at the time of examination, 2) a function to record dialogue with the patient in chronological order, 3) a function to support the detection of swollen joints, and 4) function to automatically analyze the questionnaire.

Results:

This system remotely connects a rheumatologist in the Nagasaki University Hospital (Nagasaki City, urban area) and a patient with RA and a non- rheumatologist in the Goto Central Hospital (Goto Island, rural area). A three-dimensional hologram of the patient’s hand projected in front of a rheumatologist. Using this system, we are able to evaluate joints more accurately than using a conventional videophone or web conferencing system.

Conclusion:

It is expected that this system will enable remote medical care specializing in rheumatology, which is standardized at a high level even in areas without rheumatologists such as remote islands and remote areas. This system remotely connects Nagasaki City and Goto Island, but due to the performance of the system, it is not limited to these areas and it is possible to connect rheumatologists to any area that can be connected to the network. It is also effective for the purpose of avoiding the risk of infection during long-distance hospital visits under the epidemic of COVID-19 infection.

References:

[1]Mov Disord. 2020;35:1719-1720.

Disclosure of Interests:

Shin-ya Kawashiri Speakers bureau: Speaker fees from AbbVie, Asahi Kasei, Astellas, Chugai, Eisai, Eli Lilly, Mitsubishi Tanabe, Novartis, and ONO., Grant/research support from: Research grants from Pfizer., Fumiaki Nonaka: None declared, Shinji Chiba: None declared, Tomoyuki Honda: None declared, Tomohiko Nakajima: None declared, Tomoyuki Ishikawa: None declared, Atsushi Kawakami Speakers bureau: Speaker fees from AbbVie, Actelion, Asahi Kasei, Astellas, Boehringer Ingelheim, Celltrion, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, GSK, Janssen, Kowa, MedPeer, Mitsubishi Tanabe, Novartis, ONO, Pfizer, Taisho, and Takeda., Grant/research support from: Grants and research support from AbbVie, Actelion, Asahi Kasei, Astellas, AYUMI, Boehringer Ingelheim, Bristol-Myers Squibb, Celltrion, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, Kyowa Hakko Kirin, MSD, Neopharma, Novartis, ONO, Sanofi, Taisho, Takeda Science Foundation, and Teijin

Towards Mutation-Specific Precision Medicine in Atypical Clinical Phenotypes of Inherited Arrhythmia Syndromes

Most causal genes for inherited arrhythmia syndromes (IASs) encode cardiac ion channel-related proteins. Genotype-phenotype studies and functional analyses of mutant genes, using heterologous expression systems and animal models, have revealed the pathophysiology of IASs and enabled, in part, the establishment of causal gene-specific precision medicine. Additionally, the utilization of induced pluripotent stem cell (iPSC) technology have provided further insights into the pathophysiology of IASs and novel promising therapeutic strategies, especially in long QT syndrome. It is now known that there are atypical clinical phenotypes of IASs associated with specific mutations that have unique electrophysiological properties, which raises a possibility of mutation-specific precision medicine. In particular, patients with Brugada syndrome harboring an SCN5A R1632C mutation exhibit exercise-induced cardiac events, which may be caused by a marked activity-dependent loss of R1632C-Nav1.5 availability due to a marked delay of recovery from inactivation. This suggests that the use of isoproterenol should be avoided. Conversely, the efficacy of β-blocker needs to be examined. Patients harboring a KCND3 V392I mutation exhibit both cardiac (early repolarization syndrome and paroxysmal atrial fibrillation) and cerebral (epilepsy) phenotypes, which may be associated with a unique mixed electrophysiological property of V392I-Kv4.3. Since the epileptic phenotype appears to manifest prior to cardiac events in this mutation carrier, identifying KCND3 mutations in patients with epilepsy and providing optimal therapy will help prevent sudden unexpected death in epilepsy. Further studies using the iPSC technology may provide novel insights into the pathophysiology of atypical clinical phenotypes of IASs and the development of mutation-specific precision medicine.

Multiple arrhythmic and cardiomyopathic phenotypes associated with an SCN5A A735E mutation

BACKGROUND

SCN5A mutations are associated with multiple arrhythmic and cardiomyopathic phenotypes including Brugada syndrome (BrS), sinus node dysfunction (SND), atrioventricular block, supraventricular tachyarrhythmias (SVTs), long QT syndrome (LQTS), dilated cardiomyopathy and left ventricular noncompaction. Several single SCN5A mutations have been associated with overlap of some of these phenotypes, but never with overlap of all the phenotypes.

OBJECTIVE

We encountered two pedigrees with multiple arrhythmic phenotypes with or without cardiomyopathic phenotypes, and sought to identify a responsible mutation and reveal its functional abnormalities.

METHODS

Target panel sequencing of 72 genes, including inherited arrhythmia syndromes- and cardiomyopathies-related genes, was employed in two probands. Cascade screening was performed by Saner sequencing. Wild-type or identified mutant SCN5A were expressed in tsA201 cells, and whole-cell sodium currents (I_Na) were recorded using patch-clamp techniques.

RESULTS

We identified an SCN5A A735E mutation in these probands, but did not identify any other mutations. All eight mutation carriers exhibited at least one of the arrhythmic phenotypes. Two patients exhibited multiple arrhythmic phenotypes: one (15-year-old girl) exhibited BrS, SND, and exercise and epinephrine-induced QT prolongation, the other (4-year-old boy) exhibited BrS, SND, and SVTs. Another one (30-year-old male) exhibited all arrhythmic and cardiomyopathic phenotypes, except for LQTS. One male suddenly died at age 22. Functional analysis revealed that the mutant did not produce functional I_Na.

CONCLUSIONS

A non-functional SCN5A A735E mutation could be associated with multiple arrhythmic and cardiomyopathic phenotypes, although there remains a possibility that other unidentified factors may be involved in the phenotypic variability of the mutation carriers.

Reduced current density, partially rescued by mexiletine, and depolarizing shift in activation of SCN5A W374G channels as a cause of severe form of Brugada syndrome

BACKGROUND

SCN5A-related Brugada syndrome (BrS) can be caused by multiple mechanisms including trafficking defects and altered channel gating properties. Most SCN5A mutations at pore region cause trafficking defects, and some of them can be rescued by mexiletine (MEX).

OBJECTIVE

We recently encountered symptomatic siblings with BrS and sought to identify a responsible mutation and reveal its biophysical defects.

METHODS

Target panel sequencing was performed. Wild-type (WT) or identified mutant SCN5A was transfected into tsA201 cells. After incubation of transfected cells with or without 0.1 mM MEX for 24-36 hr, whole-cell sodium currents (I_Na ) were recorded using patch-clamp techniques.

RESULTS

The proband was 29-year-old male who experienced cardiopulmonary arrest. Later, his 36-year-old sister, who had been suffering from recurrent episodes of syncope since 12 years, was diagnosed with BrS. An SCN5A W374G mutation, located at pore region of domain 1 (D1 pore), was identified in both. The peak density of W374G-I_Na was markedly reduced (WT: 521 ± 38 pA/pF, W374G: 60 ± 10 pA/pF, p < .01), and steady-state activation (SSA) was shifted to depolarizing potentials compared with WT-I_Na (V_1/2 -WT: -39.1 ± 0.8 mV, W374G: -30.9 ± 1.1 mV, p < .01). Incubation of W374G-transfected cells with MEX (W374G-MEX) increased I_Na density, but it was still reduced compared with WT-I_Na (W374G-MEX: 174 ± 19 pA/pF, p < .01 versus W374G, p < .01 versus WT). The SSA of W374G-MEX-I_Na was comparable to W374G-I_Na (V_1/2 -W374G-MEX: -31.6 ± 0.7 mV, P = NS).

CONCLUSIONS

Reduced current density, possibly due to a trafficking defect, and depolarizing shift in activation of SCN5A W374G are underlying biophysical defects in this severe form of BrS. Trafficking defects of SCN5A mutations at D1 pore may be commonly rescued by MEX.

Therapeutic Potential of Vortioxetine for Anxious Depression: A Post Hoc Analysis of Data from a Clinical Trial Conducted in Japan

AIM

Antidepressants, including selective serotonin reuptake inhibitors, often elicit a poor response in patients with major depressive disorder (MDD) with significant anxiety symptoms. This study investigated the effects of the multimodal antidepressant vortioxetine in patients with MDD and associated anxiety.

METHODS

This was a post hoc analysis of data from an 8-week, randomized, double-blind, placebo-controlled, Phase 3 study of vortioxetine (10 mg or 20 mg) in Japanese patients aged 20-75 years with recurrent MDD and a Montgomery-Åsberg Depression Rating Scale (MADRS) score of at least 26. Changes from baseline to week 8 in MADRS total score and Hamilton Depression Rating Scale (HAM-D) anxiety/somatization factor score were assessed in patients with anxious depression (HAM-D anxiety/somatization factor score ≥7) and without anxious depression.

RESULTS

Data were available for 489 patients. In patients with anxious depression, the least-squares (LS) mean difference (95% confidence interval [CI]) versus placebo in change in MADRS total score was -3.44 (-6.10, -0.77) for vortioxetine 10 mg and -4.51 (-7.15, -1.87) for vortioxetine 20 mg. In patients with non-anxious depression, the LS mean difference (95% CI) versus placebo was -1.81 (-4.71, 1.09) and -1.05 (-4.00, 1.90) for vortioxetine 10 mg and 20 mg, respectively. Changes from baseline in HAM-D anxiety/somatization factor score were greater in patients treated with vortioxetine 10 mg or 20 mg than in those treated with placebo.

CONCLUSION

Vortioxetine may be effective for patients with anxiety symptoms in MDD. Further research is warranted to investigate these effects in a real-world clinical setting.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov identifier for primary study: NCT02389816.

Early Improvement with Vortioxetine Predicts Response and Remission: A Post Hoc Analysis of Data from a Clinical Trial Conducted in Japan

AIM

Several weeks of treatment with an antidepressive agent may be required before efficacy is demonstrated in patients with major depressive disorder. This study investigated the predictive value of early partial improvement with vortioxetine for treatment response and remission.

METHODS

This was a post hoc analysis of an 8-week, randomized, double-blind, placebo-controlled, Phase 3 study of vortioxetine (10 mg or 20 mg) in Japanese patients aged 20-75 years with recurrent major depressive disorder and a Montgomery-Åsberg Depression Rating Scale (MADRS) score of at least 26. The key outcomes were the predictive value of early partial improvement (reduction in MADRS total score of ≥20% from baseline to week 2) with vortioxetine for MADRS response (≥50% decrease in score from baseline) and remission (decrease in score to ≤10) at week 8.

RESULTS

Relevant data were available for 478 patients; 62/158 patients receiving placebo, 71/162 receiving vortioxetine 10 mg, and 66/158 receiving vortioxetine 20 mg were early improvers. Early improvers receiving vortioxetine (10 mg or 20 mg) were more likely than non-early improvers to achieve a week 8 response (71.2-73.2% vs 29.7-38.0%) or remission (50.7-51.5% vs 17.4-18.7%). Positive predictive values for response and remission with vortioxetine were ~70% and ~50%, respectively; negative predictive values were ~70% and ~80%, respectively.

CONCLUSION

Improvement with vortioxetine may be predicted by early partial improvement in MADRS score. Some patients may benefit from longer-term treatment even without early improvement, another finding that may aid clinical decision-making. ClinicalTrials.gov registration for primary study: NCT02389816.

Ventricular tachycardia in cardiac sarcoidosis -prognosis, characterization of ventricular substrates and outcomes of treatment-

Background

The prognosis, the underlying substrate and clinical outcomes of treatment are unclear in patients with cardiac sarcoidosis (CS)-related ventricular tachycardia (VT).

Objective

This study investigated the prognosis and the relationship between electroanatomical mapping (EAM) and imaging findings in patients with CS-related VT.

Methods

A total of 203 CS patients (Age 68.1±11.6 years, 87 males) were enrolled at two tertiary care medical centers between 2000 and 2018. All met the 2016 Japanese Circulation Society guidelines for diagnosis of CS. They were followed for a composite of major adverse cardiac events (MACE) including cardiac death, heart transplantation, unscheduled hospitalization for heart failure, and life-threatening ventricular arrhythmias. Distribution of late gadolinium enhancement (LGE) on cardiac MRI (CMR) and/or an abnormal myocardial 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography at diagnosis were examined. The relationship between EAM and the image findings were also analyzed in patients with radiofrequency ablation (RFA) for VT.

Results

During a median follow-up of 53 months, 87 of the 203 patients (43%) experienced a MACE. Baseline factors associated with MACE were presence of sustained VT (HR, 2.43, 95% CI 1.54–3.85, P&lt;0.001), left ventricular ejection fraction below 50% (HR, 1.95 95% CI 1.07–3.56, P=0.029), and abnormal myocardial FDG uptake (HR, 2.42 95% CI 1.04–5.61, P=0.039). Overall, 69 of the 203 patients (34%) experienced sustained VT. Abnormal myocardial FDG uptake was significantly more prevalent in patients with VT than in those without (92.7% vs. 78.5%, P=0.02). A total of 25 patients (9.9%) required RFA for CS-related VT (Age 64.0±8.7 years, 12 males, 1.32±0.56 RFAs per patient). Abnormal electrocardiograms (EGM) were observed in 22 of the 25 patients (88%). LGE was more frequent than abnormal FDG uptake in areas with an abnormal EGM (77% vs. 41%; P=0.002). Over a mean follow-up period of 67-months, 13 of the 25 patients with RFA (52%) remained free of VT episodes (Figure). VT recurred in nine of the 12 patients with RFA and in 17 of the 47 patients without RFA, but was suppressed by intensive pharmacologic therapy such as the combined use of amiodarone and sotalol. In patients with CS-related VT, survival without experiencing a MACE did not differ in participants with or without RFA.

Conclusions

In our 203 CS patients, sustained VT and abnormal FDG uptake were associated with worse cardiac outcomes. The prevalence of abnormal FDG uptake was significantly higher in patients with CS-related VT, LGE on CMR was more frequent within localized areas of an abnormal EGM, suggesting that both scar itself and the associated inflammation were involved in the pathogenesis of CS-related VT. Successful RFA of CS-related VT is still challenging, and recurrence is common. Preprocedural CMR can be useful in detecting abnormal EGMs that are potential targets for substrate ablation.

Funding Acknowledgement

Type of funding source: None

Superior-Type Fast-Slow Atrioventricular Nodal Reentrant Tachycardia Phenotype Mimicking the Slow-Fast Type

BACKGROUND

Superior-type fast-slow (sup-F/S-) atrioventricular nodal reentrant tachycardia (AVNRT) is a rare AVNRT variant using a superior slow pathway (SP) as the retrograde limb. Its intracardiac appearance, characterized by a short atrio-His (AH) interval and the earliest site of atrial activation in the His-bundle, is an initial indicator for making a diagnosis.

METHODS

Among 22 consecutive patients with sup-F/S-AVNRT, 3 (age, 68-81 years) patients had an apparent slow-fast (S/F-) AVNRT characterized by a long AH interval and the earliest site of atrial activation in or superior to the His-bundle region (tachy-long-AH).

RESULTS

The diagnosis of sup-F/S-AVNRT was based on the standard criteria in 2 patients and on the occurrence of Wenckebach-type atrioventricular block during tachycardia, which was attributable to a block at the lower common pathway (LCP) below the circuit of the AVNRT, detected owing to the lower common pathway potentials, in one patient. As with the typical S/F-AVNRT, tachy-long-AH was induced after a jump in the AH interval. In contrast to typical S/F-AVNRT, fluctuation in the ventriculoatrial interval was observed during the tachy-long-AH. Ventricular overdrive pacing was unable to entrain or terminate the tachy-long-AH. Moreover, the tachy-long-AH reciprocally transited to/from sup-F/S-AVNRT spontaneously or was triggered by ventricular contractions while the atrial cycle length and earliest site of atrial activation remained unchanged. Both tachycardias were cured by ablation at a single site in the right-side para-Hisian region of 2 patients and the noncoronary aortic cusp of one patient. Collectively, the essential circuit of both tachycardias was identical, and the tachy-long-AH was diagnosed as another phenotype of sup-F/S-AVNRT accompanied by sustained antegrade conduction via another bystander slow pathway breaking through the His-bundle owing to the repetitive antegrade block at the lower common pathway, thus representing a long AH interval during the ongoing sup-F/S-AVNRT.

CONCLUSIONS

An unknown sup-F/S-AVNRT phenotype exists that apparently mimics the typical S/F-AVNRT and is also an unknown subtype of apparent S/F-AVNRT.

Comparative Effectiveness of Angiotensin II Receptor Blockers in Patients With Hypertension in Japan - Systematic Review and Network Meta-Analysis

Background: Angiotensin II receptor blockers (ARBs) are widely used for the management of hypertension in Japan; however, comparative efficacy data within the ARB drug class remain limited. Methods and Results: This systematic literature review identified randomized controlled trials (RCT) indexed in PubMed and Ichushi in Japanese patients with hypertension receiving ARB monotherapy (azilsartan, candesartan cilexetil, irbesartan, losartan potassium, olmesartan medoxomil, telmisartan, valsartan) in at least 1 arm. Of 763 RCTs identified, 77 met the eligibility criteria; of which, 37 reported mean change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline in the office setting and were used to construct the network. A fixed-effects model (FEM) showed the effect of each drug vs. the reference, azilsartan. Using the FEM, the mean (95% credible interval) change from baseline in SBP/DBP for candesartan cilexetil, irbesartan, losartan potassium, olmesartan medoxomil, telmisartan, and valsartan was 3.8 (2.9-4.8)/2.6 (2.0-3.1), 4.8 (2.0-7.5)/3.7 (1.8-5.6), 3.0 (0.8-5.1)/1.9 (0.5-3.3), 3.2 (1.2-5.1)/2.7 (1.3-4.1), 3.2 (0.8-5.6)/2.0 (0.3-3.6), and 3.1 (1.1-5.1)/2.4 (1.1-3.8) mmHg, respectively. Conclusions: The results of this meta-analysis provide evidence that azilsartan has a more favorable efficacy profile than the other ARBs in reducing SBP and DBP.

Novel Cardiocerebral Channelopathy Associated with a KCND3 V392I Mutation

While a KCND3 V392I mutation uniquely displays a mixed electrophysiological phenotype of Kv4.3, only limited clinical information on the mutation carriers is available. We report two teenage siblings exhibiting both cardiac (early repolarization syndrome and paroxysmal atrial fibrillation) and cerebral phenotypes (epilepsy and intellectual disability), in whom we identified the KCND3 V392I mutation. We propose a link between the KCND3 mutation with a mixed electrophysiological phenotype and cardiocerebral phenotypes, which may be defined as a novel cardiocerebral channelopathy.

Role of the voltage sensor module in Nav domain IV on fast inactivation in sodium channelopathies: The implication of closed-state inactivation

The segment 4 (S4) voltage sensor in voltage-gated sodium channels (Na_vs) have domain-specific functions, and the S4 segment in domain DIV (DIVS4) plays a key role in the activation and fast inactivation processes through the coupling of arginine residues in DIVS4 with residues of putative gating charge transfer center (pGCTC) in DIVS1-3. In addition, the first four arginine residues (R1-R4) in Na_v DIVS4 have position-specific functions in the fast inactivation process, and mutations in these residues are associated with diverse phenotypes of Na_v-related diseases (sodium channelopathies). R1 and R2 mutations commonly display a delayed fast inactivation, causing a gain-of-function, whereas R3 and R4 mutations commonly display a delayed recovery from inactivation and profound use-dependent current attenuation, causing a severe loss-of-function. In contrast, mutations of residues of pGCTC in Na_v DIVS1-3 can also alter fast inactivation. Such alterations in fast inactivation may be caused by disrupted interactions of DIVS4 with DIVS1-3. Despite fast inactivation of Na_vs occurs from both the open-state (open-state inactivation; OSI) and closed state (closed-state inactivation; CSI), changes in CSI have received considerably less attention than those in OSI in the pathophysiology of sodium channelopathies. CSI can be altered by mutations of arginine residues in DIVS4 and residues of pGCTC in Na_vs, and altered CSI can be an underlying primary biophysical defect of sodium channelopathies. Therefore, CSI should receive focus in order to clarify the pathophysiology of sodium channelopathies.

Biophysical defects of an SCN5A V1667I mutation associated with epinephrine-induced marked QT prolongation

BACKGROUND

The epinephrine infusion test (EIT) typically induces marked QT prolongation in LQT1, but not LQT3, while the efficacy of β-blocker therapy is established in LQT1, but not LQT3. We encountered an LQT3 family, with an SCN5A V1667I mutation, that exhibited epinephrine-induced marked QT prolongation.

METHODS

Wild-type (WT) or V1667I-SCN5A was transiently expressed into tsA-201 cells, and whole-cell sodium currents (I_Na ) were recorded using patch-clamp techniques. To mimic the effects of epinephrine, I_Na was recorded after the application of protein kinase A (PKA) activator, 8-CPT-cAMP (200 μM), for 10 minutes.

RESULTS

The peak density of V1667I-I_Na was significantly larger than WT-I_Na (WT: 469 ± 48 pA/pF, n = 20; V1667I: 690 ± 62 pA/pF, n = 19, P < .01). The steady-state activation (SSA) and fast inactivation rate of V1667I-I_Na were comparable to WT-I_Na . V1667I-I_Na displayed a significant depolarizing shift in steady-state inactivation (SSI) in comparison to WT-I_Na (V_1/2 -WT: -88.1 ± 0.8 mV, n = 17; V1667I: -82.5 ± 1.1 mV, n = 17, P < .01), which increases window currents. Tetrodotoxin (30 μM)-sensitive persistent V1667I-I_Na was comparable to WT-I_Na . However, the ramp pulse protocol (RPP) displayed an increased hump in V1667I-I_Na in comparison to WT-I_Na . Although 8-CPT-cAMP shifted SSA to hyperpolarizing potentials in WT-I_Na and V1667I-I_Na to the same extent, it shifted SSI to hyperpolarizing potentials much less in V1667I-I_Na than in WT-I_Na (V_1/2 -WT: -92.7 ± 1.3 mV, n = 6; V1667I: -85.3 ± 1.6 mV, n = 6, P < .01). Concordantly, the RPP displayed an increased hump in V1667I-I_Na , but not in WT-I_Na .

CONCLUSIONS

We demonstrated an increase of V1667I-I_Na by PKA activation, which may provide a rationale for the efficacy of β-blocker therapy in some cases of LQT3.

AB1198 DECREASING OF TOTAL AND UNILATERAL KNEE ARTHROPLASTIES DUE TO RHEUMATOID ARTHRITIS BUT INCREASING IN OSTEOARTHRITIS IN OUR INSTITUTES IN LAST DECADE OF SUPER-AGING SOCIETY

Background:

The rate of elderly people over 65 year-old increased from 22.1 % in 2008 to 27.7% in 2017 in Japan, also from 27.1 % to 32.3 % in our super-aging area1, 2. The number of total and unilateral knee arthroplasty (TKA, UKA) have increased annually in all over the world according to the larger population of elderly people due to osteoarthritis (OA)3. In fact, the numbers of primary TKA predicted increasing from six hundred fifty-six thousand cases at 2010 to one million three hundred seventy-six thousand cases at 2020 in USA4. In the other hand, rheumatoid arthritis (RA) therapy have been remarkably improved from starting to use biologic agents since 2003 in Japan5. The rate of orthopaedic surgery may reflect trends in disease severity and drug management of RA5.

Objectives:

The aim of study is to reveal the rate of TKA, including UKA and revision TKA in elderly people in our super-aging area of Japan.

Methods:

We surveyed the number and cause of primary and revision TKA and UKA in our institutes using the data of diagnosis procedure combination and the record of surgeries in the last decade.

Results:

Figure 1.

Table 1.2008-122013-17TimesOsteoarthritis15652252*1.3Rheumatoid arthritis13181*0.6Trauma155Osteonecrosis of femoral condylar2041*2.1Revision21391.9Total17382418*1.4*p< 0.05

Conclusion:

The number and rate of primary TKA/UKA due to RA decreased year by year because of progression of modern medication therapy. In the other hand, in case of OA increased because of increasing of elderly people affected by knee OA in the super-aging society.

References:

[1]National Institute of Population and Social Security Research. Japanese Mortality Database, 2018.http://www.ipss.go.jp/

[2]Yamagata prefecture, Health and longevity Promotion Section. Rate of elderly people in Yamagata prefecture, 2018.http://www.pref.yamagata.jp/ou/kikakushinko/020052/tokei/jinkel.html

[3]Annual report 2017 of replacement arthroplasty in Japan. The Japanese Society For Replacement Arthroplasty The Japan Arthroplasty Register.https://jsra.info/jar-report.html

[4]Kurtz SM, et al. J Bone Joint Surg Am. 96: 624-30, 2014.

[5]Momohara S, et al. J Rheumatol. 41:862-5, 2014.

Disclosure of Interests:

None declared

THU0023 DETAILED PROFILE OF CO-OCCURRENCE OF RELAPSING POLYCHONDRITIS AND AUTOIMMUNE THYROID DISEASE

Background:

Relapsing polychondritis (RP) is a rare inflammatory disease, which is characterized by recurrent inflammation and destruction of cartilage tissues. RP also has the profile of autoimmune disease and is often complicated with other autoimmune disease. Autoimmune thyroid disease (AITD) is one of common autoimmune diseases, which consists of Graves’ disease (GD) and Hashimoto’s thyroiditis (HT). While RP is reported to be complicated with AITD1), there has been no study on detailed profile of co-occurrence of RP and AITD.

Objectives:

We aimed to reveal whether there is common (statistically significant) co-occurrence of RP and AITD. We also analyzed clinical and genetic profiles characterizing the co-occurrence.

Methods:

We recruited 117 patients with RP and checked their medical records in order to obtain the information about compilation of AITD and clinical features. In addition, we genotyped Human Leucocyte Antigen (HLA) A, B Cw, DRB1, DQB1 and DPB1 alleles for 88 of the 117 patients. Co-occurrence ratio was compared with prevalence of AITD in the Japanese population. Associations of co-occurrence of AITD with clinical manifestations or HLA alleles were analyzed among the patients.

Results:

Among the 117 patients with RP, 5 (4.3%) and 6 (5.1%) patients had GD and HT, respectively. Patients with RP were more likely to be complicated with GD (p=1.04×10-3, OR: 7.15, 95%CI 2.68~ 18.14) but not with HT (p=0.50, 95%CI 0.59~1.27), compared with prevalence in general Japanese population (0.62% and 5.9%, respectively2)). RP patients with GD showed a trend to have nasal involvement (100% vs 45.5%, p=0.023, OR: 2.58, 95%CI 1.09~∞). We did not observe any differences in clinical manifestation in patients with RP and HT. HLA- DPB1*02:02 demonstrated a trend toward GD complication (20% vs 2.3%, p=0.035, OR: 10.41, 95%CI 1.23~65.38). There were no association of HLA in the complication of HT among patients with RP.

Conclusion:

Patients with RP have high co-occurrence ratio of GD. Patients with the two diseases may be characterized by nasal involvement and HLA-DPB1*02:02.

References:

[1]Kung AW et al. Graves’ ophthalmopathy and relapsing polychondritis. Clin Exp Rheumatol. 1995 Jul-Aug;13(4):501-3.

[2]Nagataki S et al. Thyroid diseases among atomic bomb survivors in Nagasaki. JAMA. 1994 Aug 3;272(5):364-70.

Disclosure of Interests:

Toshiki Nakajima Speakers bureau: Bristol-Myers Squibb and Novartis, Hajime Yoshifuji Grant/research support from: Astellas Pharma. (Outside the field of the present study.), Speakers bureau: Chugai Pharmaceutical. (Outside the field of the present study.), Yoshihisa Yamano: None declared, Hiroshi Handa: None declared, Koichiro Ohmura Grant/research support from: Astellas Pharma, AYUMI Pharmaceutical, Chugai Pharmaceutical, Daiichi Sankyo, Eisai, Japan Blood Products Organization, Mitsubishi Tanabe Pharma, Nippon Kayaku, Nippon Shinyaku, Sanofi, and Takeda Pharmaceutical., Speakers bureau: AbbVie, Actelion Pharmaceuticals Japan, Asahi Kasei Pharma, AYUMI Pharmaceutical, Bristol-Myers Squibb, Chugai Pharmaceutical, Eisai, Eli Lilly and Company, GlaxoSmithKline, Janssen Pharmaceutical, Mitsubishi Tanabe Pharma, Novartis Pharma, and Sanofi., Tsuneyo Mimori: None declared, Chikashi Terao Grant/research support from: Actelion, Speakers bureau: Asteras, Asahi Kasei Pharma, Ono and Tanabe-Mitsubishi