Preclinical proof-of-concept study: antisense-mediated knockdown of CALM as a therapeutic strategy for calmodulinopathy

Background

Calmodulin (CaM) is a ubiquitous Ca2+ sensor molecule encoded by three distinct calmodulin genes, CALM1–3, and has an important role for cardiac ion channel function. Recently, heterozygous missense mutations in CALM genes were reported to cause a new category of life-threatening genetic arrhythmias such as long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT), which is called as “calmodulinopathy”. The patients with calmodulinopathy show poor prognosis and there is no effective treatment for them.

Purpose

Considering the dominant-negative effect of mutant calmodulin proteins produced by heterozygous missense mutations in CALMs, we aimed to prove the concept of antisense-based therapy to treat calmodulinopathy using human iPS cell-derived cardiomyocyte (hiPSC-CM) model.

Methods

We designed multiple locked nucleic acid (LNA) gapmer-antisense oligonucleotides (ASOs) targeting CALM2 and analyzed the silencing efficiency and toxicity in cultured cells to select the most potent ASO. Using CMs differentiated from hiPSCs which were generated form a 12-year-old boy with LQTS carrying a heterozygous CALM2-N98S mutation, CALM2 expression and action potentials (APs) were analyzed to evaluate the efficacy of ASOs.

Results

We identified several ASOs which reduced CALM2 expression without affecting cell viability in human cultured cells (HepG2) (ASO 50 nM, n=2; Figure 1A). Considering further experiments in vivo mouse model, we investigated the CALM2 silencing activity in mouse cultured cells (3T3-L1) without transfection (free-uptake) (ASO 1 μM, n=2; †ASOs have homologous sequence between human and mouse; Figure B). After free-uptake CALM2 silencing analysis in 3T3-L1 cells, we identified that ASO #2 has the most potent CALM2 silencing activity and low cytotoxicity (Figure 1B). ASO #2 effectively reduced CALM2 expression even in hiPSC-CMs (ASO(−): n=3, lipofection: n=4, free-uptake: n=3; P<0.05; Figure 1C). In action potential recordings, we demonstrated that ASO #2 ameliorated prolonged AP durations (APD90) in N98S-hiPSC-CMs at 0.5 Hz pacing (ASO(−): 666±123 ms (n=7), lipofection: 329±21 ms (n=8), free-uptake: 388±34 ms (n=12); P<0.05; Figure 1D).

Conclusion

Our results using patient-derived hiPSC-CM model suggest that ASO-based therapy might be a promising strategy for the treatment of calmodulinopathy.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Nissan Chemical Corporation

Molecular mechanism of a new cardiac syndrome associated with a regulatory element deletion of chromosome 4q25

Introduction

We identified a large family of 53 members of whom 22 present a new cardiac syndrome characterized by electrical disorders and developmental defects following an autosomal dominant model. Among the affected family members 6 are implanted with a pacemaker, 2 experienced syncope and one a sudden death at 43yo. Linkage analysis points, with high confidence, to the chromosome 4q25 region. This region is associated with the Ankyrin syndrome (mutation in ANK2) sharing partly the electrical defects observed in the affected family members. No mutation was found in the coding region of the 4q25 region as well as in the coding and non-coding part of the ANK2.

Objective

Our aims are first to identity the responsible mutation present in this family and understand the molecular mechanisms leading to this new syndrome.

Method

Whole genome sequencing (WGS) has been employed to identify genetic variants responsible for this syndrome. ChIP-seq and ATAC-seq were used for functional annotation and genome editing (CRISPR-Cas9) to generate iPS cellular models.

Results

By WGS we uncovered a deleted region of 15kb in a gene desert area on 4q25, segregating in all affected relatives. Five other families (3 French and 2 Japanese) presenting the same phenotype show overlapping deletions. We generated human cardiac epigenetic data and identified among the 15kb deleted region a unique active enhancer region within the presence of a transcript factor CTCF binding site. Isogenic cell lines where the 15kb and the CTCF binding have been deleted are under investigation.

Conclusion

We identified a new cardiac syndrome and for the first time a mutation located within a gene desert area leading to severe and complex cardiac disorders. We demonstrated the presence of a likely gene regulatory element. Experiments are ongoing to characterize the molecular mechanisms and consequence of the deletion on gene expression.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Pays de la loire - Etoiles montantes

Hyperuricemia impaired nitric oxide bioavailablity and deteriorated pulmonary arterial hypertension via a uric acid transporter, URATv1 in xanthine oxidoreductase (XOR)-independent manner

Background

Hyperuricemia occurs in approximately 80% in patients with pulmonary arterial hypertension (PAH) and is positively correlated with pulmonary arterial pressure (PAP). It has been reported that uric acid (UA) reduced endothelium derived nitric oxide (NO) production in porcine pulmonary arterial endothelial cells (PAEC). However, the effects of UA and xanthine oxidoreductase (XOR), catalytic enzyme of UA, on the development of PAH have not been fully elucidated.

Purpose

We examined the followings; (1) the effects of hyperuricemia on the endothelial function and the development of PAH in rats (2) the therapeutic effects of UA transporter inhibitor on PAH in rats, and (3) the role of XOR in PAH in mice.

Methods

We used normal and 5-wk Sugen5416/Hypoxia/Normoxia-exposed (SU/Hx/Nx) rats. Gene expression levels of URATv1, a UA transporter, were measured by RT-PCR. We determined the isometric tension of PA rings isolated from normal rats. The study with the isolated perfused lung preparation was performed in SU/HX/Nx rats. To investigate the chronic effect of UA on the development of PAH, hyperuricemia was induced by the administration of 2% oxonic acid (OA) in diet for 6-wk. Benzbromarone (BBR, 10mg/kg/day, diet, from weeks 0 to 5), a URATv1 transporter inhibitor, was administered in the SU/Hx/Nx-rats with or without 2%OA. To examine the role of XOR in PAH, XOR+/− and wild type (WT) mice were exposed to 3-wk Nx or Hx (10% O2).

Results

The mRNA of URATv1 was detected in the normal lungs. Isometric tension study showed that UA (8 mg/dl) inhibited acetylcholine-induced vasorelaxation. In perfused lung preparations, UA acutely increased estimated PVR in a dose-dependent manner (1.6–16.0mg/dl) with reducing cGMP levels in the lungs. BBR significantly attenuated the pressor response to UA. UA levels in the plasma and the lung tissues were significantly elevated in SU/Hx/Nx-rats with 2%OA (normal vs. vehicle vs. 2%OA, plasma: 0.24±0.01 vs. 0.80±0.14 and 1.44±0.17 mg/dl; lung tissues: 68±3 vs. 142±3 and 377±46 pmol/g tissue). They exhibited further elevation of right ventricle systolic pressure (RVSP) (31±2 vs. 72±6 vs. 101±3 mmHg) and Ea (a marker of RV afterload) (0.24±0.04 vs. 0.97±0.15 vs. 2.36±0.49 mmHg/μL) with the exacerbation of occlusive lesions of PAs. BBR had no changes in the UA levels in the plasma (1.93±0.30 mg/dL), but significantly reduced the UA levels in the lung tissues (101±10 pmol/g tissue) and attenuated the increase in RVSP (53±8mmHg) and Ea (0.21±0.05 mmHg/mL) in the SU/Hx/Nx-rats with 2%OA. On the other hand, BBR had no effects on RVSP (76±7 mmHg) and Ea (0.91±0.15 mmHg/mL) in the SU/Hx/Nx-rats without 2%OA. There were no significant differences in RVSP between XOR+/− mice with Hx and WT with Hx (26±2 vs. 26±2 mmHg).

Conclusions

Hyperuricemia itself impairs endothelial function and deteriorates PAH via URATv1 in a XOR-independent manner. UA can be a novel therapeutic target for PAH.

Funding Acknowledgement

Type of funding source: None

Predictors of the usefulness of mirogabalin for neuropathic pain: a single-institution retrospective study

Mirogabalin is a novel, preferentially selective α2δ-1 ligand to treat neuropathic pain. However, this agent is not always effective for patients with neuropathic pain. We therefore attempted to identify factors that could predict the efficacy of mirogabalin. The study comprised 133 patients given mirogabalin for alleviation of neuropathic pain between April and November 2019 at our hospital. Variables were extracted from medical records for regression analysis of factors associated to alleviation of neuropathic pain. We evaluated the effect of mirogabalin at two weeks after administration. Groups were categorized according to degree of improvement: poor, effective, or very effective. Multivariate ordered logistic regression analysis was conducted to identify predictors for the usefulness of mirogabalin. Threshold measures were analysed using receiver operating characteristic (ROC) curves. Maintenance dose [odds ratio (OR) = 0.90; 95% confidence interval (CI) = 0.84-0.98; P = 0.01], concomitant use of opioids (OR = 0.26, 95% CI = 0.08-0.83; P = 0.023) and Neurotropin^® (NTP) (OR = 4.78, 95% CI =1.04-21.93; P = 0.044) were factors significantly correlated to the effect of mirogabalin. ROC curve analysis of the effective group indicated a threshold maintenance dose of≤ 20 mg/day (area under the curve [AUC] = 0.53). In conclusion, maintenance dose (≤ 20 mg), concomitant use of opioids and NTP were identified as predictors for the utility of mirogabalin.

Mechanical thrombectomy in acute ischemic stroke patients with left ventricular assist device

OBJECTIVES

As the number of patients with left ventricular assist device (LVAD) implantation has been increasing, treatment of LVAD-related ischemic stroke is becoming a critical issue. We sought to clarify the features of mechanical thrombectomy in LVAD-related stroke with large vessel occlusion.

METHODS

In a multi-center, retrospective case-control study, we compared 20 LVAD-related strokes with 33 non-LVAD strokes, all of which had large vessel occlusion in the anterior circulation treated with mechanical thrombectomy. A comparative histopathological examination of the retrieved thrombi was also performed.

RESULTS

Successful reperfusion was achieved in 75% of the LVAD-related strokes. The time from onset to reperfusion was similar to that of non-LVAD strokes, but the total number of device passes required for reperfusion (median, 2.5 versus 1, P = 0.01) and the incidences of post-procedural parenchymal and subarachnoid hemorrhage (25% versus 3%, P = 0.02 and 55% versus 15%, P = 0.01, respectively) were higher in LVAD-related strokes. Symptomatic intracranial hemorrhage occurred in 4 patients (20%) with LVAD-related strokes. The histopathological analysis revealed that the ratio of erythrocyte components was significantly lower in thrombi retrieved from patients with LVAD-related stroke than in those with non-LVAD stroke (19 ± 6% versus 41 ± 17%, P = 0.01).

CONCLUSIONS

Mechanical thrombectomy is feasible in patients with LVAD-related stroke. However, repetitive device passes are needed to achieve successful reperfusion mainly because of the structurally organized thrombi, and the higher risk of hemorrhagic complications should be considered, while offering this therapeutic alternative.

Mastication Affects Transcriptomes of Mouse Microglia

BACKGROUND/AIM

We investigated whether mastication affects microglia, whose activity is thought to be associated with cognition and brain tumor progression.

MATERIALS AND METHODS

We kept mice by feeding either a hard or soft diet for 2, 4 or 8 months. After each period, we removed the whole brains and isolated microglia. The total RNA extracted from each brain's microglia was subjected to DNA microarray analysis.

RESULTS

Many genes were found to be significantly differentially expressed between hard- and soft-diet-fed mice in each group of the same feeding period. The expression of several genes involved in the regulation of actin cytoskeleton was down-regulated in the soft-diet-fed mice.

CONCLUSION

Mastication may affect microglia's roles in cognition as well as their neuroimmune activity through their activity of patrolling the brain.

FRI0097 EFFECTS OF BIOLOGICAL DISEASE-MODIFYING ANTI-RHEUMATIC DRUG TREATMENT ON PHYSICAL ACTIVITY, MUSCLE POWER, AGILITY AND INHIBITION OF FALL IN PATIENTS WITH RHEUMATOID ARTHRITIS -THE 2-YEAR RESULTS

Background:

Treatment with biological DMARDs (bDMARDs) rapidly improves signs and symptoms in patients with rheumatoid arthritis (RA). The efficacy of these bDMARDs was evaluated using composite measures or biomarkers used in daily clinical practice or clinical studies. Although a rapid improvement in composite measures or biomarkers is important in the treatment of RA, the primary goal of treatment is improvement of long-term health-related quality of life (HR-QOL) [1]. HR-QOL is evaluated based on physical functions (PF) such as muscle power and agility. We reported the 1-year results of our study presented at EULAR 2019 [2]. The present study was conducted to investigate the 2-year results of our study by including more patents than those included in the previous one.

Objectives:

This study was aimed at investigating the efficacy of bDMARDs with respect to PF and fall risk in RA patients.

Methods:

At our institute, in addition to routine rheumatology evaluation, periodic evaluation of physical function is performed by staff members in our rehabilitation center in RA patients in whom the first bDMARD treatment was initiated in Oct. 2015–Feb. 2018. In total, 41 cases were registered in this study. Evaluation of PF included evaluation of muscle power [grasping power (GP) and knee extension power (KEP)]; agility [time up and go test (TUG) and 10-m walking time (10 mW)]; and a questionnaire using modified HAQ, portable fall risk index [3], and the 25-question geriatric locomotive function scale (locomo25) [4] at baseline (BL), which implies the time at the initiation of bDMARD treatment, i.e., 1, 3, 6, 12, and 24 months. Disease activity of RA was evaluated at the same time points. Although 2 years had elapsed from BL in 37 patients, 13 patients dropped out from the evaluation of physical function owing to cessation of bDMARD treatment, rejection of evaluation for physical function, or major joint surgery performed in a patient. The results of 24 patients who completed the evaluation at 24 months were investigated in this study.

Results:

Baseline characteristics of the 24 patients were as follows: mean age 60.8 years, RA duration 12.3 years, mean SDAI 19.0, and mean CRP level 2.1 mg/dl. The bDMARDs used in the study were abatacept in 7 patients, adalimumab in 4 patients, tocilizumab in 4 patients, golimumab in 4 patients, etanercept in 3 patients, certolizumab in 1 patient, and an infliximab biosimilar in 1 patients. Data are presented as mean values at BL and at 1, 3, 6, 12, and 24 months (Fig.1). SDAI and CRP levels were significantly improved at and after 1 month. GP and KEP were significantly improved at and after 3 and 6 months. TUG and 10 mW results were significantly improved at and after 3 and 6 months. Modified HAQ results were significantly improved at and after 3 months. Locomo25 scores were significantly improved at and after 1 month. Portable fall risk index values were significantly improved at and after 12 months.

Conclusion:

Although there was a rapid improvement in the signs and symptoms of RA after the initiation of bDMARD treatment, improvement in PF was slightly delayed. Significant improvement of muscle power and agility was achieved after 3–6 months onward. Inhibition of fall risk was achieved at and after 12 months after the initiation of bDMARD treatment. These results suggest that physiotherapy plays a vital role in RA patients who undergo treatment with bDMARDs to gain more rapid improvement of PF.

References:

[1]Smolen JS et al. Ann Rheum Dis, 2016.

[2]Hirano Y et al. Ann Rheum Dis, suppl. 2, 2019.

[3]Toba K et al. Jpn J Geriat, 2005.

[4]Seichi A at al. J Orthop Sci, 2012.

Disclosure of Interests:

Yuji Hirano Speakers bureau: Tanabe-Mitsubishi, Pfizer, Eisai, Abbie, Chugai, Bristol-Meyers, Jansen, Astellas, UCB, Eli-Lilly, Asahikasei, Daiichi-Sankyo, Amgen, Ayako Morisaka: None declared, Hironobu Kosugiyama: None declared, Shiori Inuzuka: None declared, Takeshi Kamiya: None declared, Hiroyuki Mori: None declared, Naohito Morishima: None declared, Tomoji Ishikawa: None declared

P1050General anesthesia improved rate of first-pass pulmonary vein isolation by radiofrequency ablation in patients with atrial fibrillation

Background

Pulmonary vein isolation (PVI) with radiofrequency ablation (RFA) is one of the important procedures for atrial fibrillation (AF). Attaining the stability of RFA, respiratory management and pain control during the procedure are required.

Purpose

We compared the characteristic parameters and procedural outcomes between general anesthesia and moderate (conscious) sedation in patients with AF performed RFA.

Methods

We performed a retrospective, 2-center observational study to compare the general anesthesia with moderate sedation during RFA on AF from January 2018 until December 2018. In general anesthesia group, we administrated propofol and muscle relaxants under mechanical ventilation. In moderate sedation group, we administrated dexmedetomidine and/or propofol with analgesic drug. Procedural time of AF ablation, first-pass PVI (pulmonary vein isolation after completing the right or left circle) were assessed.

Results

A total of 98 patients with mean age 66 ± 11 years were enrolled (80 males, 81%). Of these, 19 patients were performed RFA under general anesthesia and 79 patients were performed under moderate sedation. Age, gender, BMI, medications before admission and CHADs2 score (general anesthesia:1.9 ± 1.2 vs moderate sedation:1.5 ± 1.1, p = 0.14), left atrium diameter (40.2 ± 6.2 vs 40.6 ± 6.8 mm, p = 0.81) and proportion of paroxysmal AF (47.4 vs 54.4%, p = 0.61) were similar between two groups. Our study found catheter RFA with general anesthesia to be associated with reduced procedural time (161 ± 29 vs 241 ± 58 minutes, p < 0.01) and improved the rate of first-pass PVI (left pulmonary vein: 84.2 vs 59.5%, p = 0.06 and right pulmonary vein: 84.2 vs 58.2%, p =0.04).

Conclusions

RFA under general anesthesia improved first-pass PVI (quality of PVI) and shortened procedural time. General anesthesia may attribute to attaining the catheter and patient stability during RFA for PVI.

0141 A Novel, Orally Available Orexin 2 Receptor-Selective Agonist, TAK-994, Shows Wake-Promoting Effects Following Chronic Dosing in an Orexin-Deficient Narcolepsy Mouse Model

Introduction

The use of an orexin 2 receptor (OX2R) agonist may be a promising approach for the treatment of narcolepsy type 1. TAK-994 is a novel, orally available OX2R-selective agonist with >700-fold selectivity against orexin 1 receptor. Single administration of TAK-994 ameliorates narcolepsy-like symptoms such as fragmentation of wakefulness and cataplexy-like episodes in orexin/ataxin-3 mice, a narcolepsy mouse model with orexin deficiency. In this study, we evaluated the effect of chronic dosing with TAK-994 on sleep/wakefulness states in orexin/ataxin-3 mice.

Methods

Orexin/ataxin-3 mice were grouped into two cohorts: a control group and a 14-day treatment group. In the control group, vehicle was administered orally to mice three times a day: zeitgeber time 12 (ZT12), ZT15 and ZT18, for 14 days. In the 14-day treatment group, TAK-994 was administered orally to mice at ZT12, ZT15 and ZT18 for 14 days. Electroencephalogram/electromyogram analysis was performed on day 1 and day 14 (ZT12-ZT21), and the subsequent sleep phase (ZT0-ZT10).

Results

On day 1, TAK-994 significantly increased wakefulness time, accompanied by a decrease in non-rapid eye movement (NREM) sleep time and rapid eye movement (REM) sleep time, in orexin/ataxin-3 mice compared with the control group. On day 14, TAK-994 also significantly increased wakefulness time, and decreased NREM sleep time and REM sleep time in orexin/ataxin-3 mice. There were no changes in the time spent in wakefulness, NREM sleep and REM sleep during the subsequent sleep phase after chronic dosing with TAK-994.

Conclusion

Wake-promoting effects of TAK-994 were observed following chronic dosing for up to 14 days in orexin/ataxin-3 mice with no rebound of sleep. Overall, there was no clear difference in efficacy between the single and repeated administration of TAK-994 in orexin/ataxin-3 mice.

Support

This work was conducted by Takeda Pharmaceutical Company Limited.

0142 TAK-925, an Orexin 2 Receptor-Selective Agonist, Enhanced Cortical Arousal in a Narcolepsy Mouse Model Different from Effects of Modafinil

Introduction

Patients with narcolepsy type 1 (NT1) suffer from distressing symptoms such as excessive daytime sleepiness (EDS) and cataplexy. Modafinil is widely used as a therapy for NT1; however, it has limited efficacy for EDS and no efficacy for cataplexy. TAK-925 is an orexin 2 receptor (OX2R)-selective agonist which improves multiple symptoms of narcolepsy such as fragmentation of wakefulness and cataplexy-like episodes, and also reduces weight gain, in orexin/ataxin-3 mice, a narcolepsy mouse model. An early proof of concept study showed TAK-925 increased wakefulness compared to placebo in individuals with NT1; however, a head-to-head comparison between TAK-925 and modafinil in NT1 has not been performed to date. In this study, we carefully compared the wake-promoting effects of TAK-925 and modafinil in orexin/ataxin-3 mice.

Methods

TAK-925 or modafinil was administered to orexin/ataxin-3 mice at zeitgeber time 12, and the sleep/wakefulness states were evaluated based on electroencephalogram (EEG) and electromyogram measurements. EEG spectral analysis was performed by fast Fourier transform during wakefulness. EEG frequency band was divided into five frequency bands: delta, theta, alpha, beta, and gamma.

Results

Both TAK-925 and modafinil significantly increased wakefulness time, and ameliorated fragmentation of wakefulness, in orexin/ataxin-3 mice during active phase. In contrast, TAK-925, but not modafinil, significantly decreased delta power, and increased alpha and gamma power during wakefulness in orexin/ataxin-3 mice, suggesting a shift in EEG power density toward higher frequencies.

Conclusion

TAK-925, but not modafinil, enhanced cortical arousal and suppressed signs of somnolence and drowsiness. In a phase 1 study in individuals with NT1, TAK-925 was found to have pronounced effects on the maintenance of wakefulness test, reaching a total duration of 40 minutes wake time at some doses tested. Spectral analysis will be evaluated in future studies in NT1 patients.

Support

This work was conducted by Takeda Pharmaceutical Company Limited.

Search for η^{'} Bound Nuclei in the ^{12}C(γ,p) Reaction with Simultaneous Detection of Decay Products

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2  nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Region- and neuronal-subtype-specific expression of Na,K-ATPase alpha and beta subunit isoforms in the mouse brain

Na,K‐ATPase is a ubiquitous molecule contributing to the asymmetrical distribution of Na⁺ and K⁺ ions across the plasma membrane and maintenance of the membrane potential, a prerequisite of neuronal activity. Na,K‐ATPase comprises three subunits (α, β, and FXYD). The α subunit has four isoforms in mice, with three of them (α1, α2, and α3) expressed in the brain. However, the functional and biological significances of the different brain isoforms remain to be fully elucidated. Recent studies have revealed the association of Atp1a3, a gene encoding α3 subunit, with neurological disorders. To map the cellular distributions of the α subunit isoforms and their coexpression patterns, we evaluated the mRNA expression of Atp1a1, Atp1a2, and Atp1a3 by in situ hybridization in the mouse brain. Atp1a1 and Atp1a3 were expressed in neurons, whereas Atp1a2 was almost exclusively expressed in glial cells. Most neurons coexpressed Atp1a1 and Atp1a3, with highly heterogeneous expression levels across the brain regions and neuronal subtypes. We identified parvalbumin (PV)‐expressing GABAergic neurons in the hippocampus, somatosensory cortex, and retrosplenial cortex as an example of a neuronal subtype expressing low Atp1a1 and high Atp1a3. The expression of Atp1b isoforms was also heterogeneous across brain regions and cellular subtypes. The PV‐expressing neurons expressed a high level of Atp1b1 and a low level of Atp1b2 and Atp1b3. These findings provide basic information on the region‐ and neuronal‐subtype‐dependent expression of Na,K‐ATPase α and β subunit isoforms, as well as a rationale for the selective involvement of neurons expressing high levels of Atp1a3 in neurological disorders.

The 31-nucleotide Y4-RNA fragment in plasma is a potential novel biomarker

The 31- and 32-nt 5′-fragment of Y4-RNA (Y4RNAfr) exists abundantly in human peripheral blood plasma. Although physiological roles of the plasma Y4RNAfr are not well established, its potential utility as a diagnostic/prognostic marker for acute coronary syndrome was suggested. In this paper, to establish a normal range of the Y4RNAfr level in plasma, we measured plasma Y4RNAfr levels of 40 healthy persons using the method we have developed, and compared them with other blood test data. From the obtained data, we tentatively regarded <0.1 fmol/ng as normal for the Y4RNAfr level in peripheral blood plasma. And the white blood cell count (WBC) and the C-reactive protein (CRP) level showed moderate positive correlations with the Y4RNAfr level, suggesting that Y4RNAfr could be a potential novel inflammatory marker. We also measured the Y4RNAfr level in peripheral blood plasma from four multiple myeloma patients. The plasma Y4RNAfr level was abnormal in all four myeloma patients, and the levels for two patients were far beyond the normal level. The WBC for each patient was normal and the CRP levels for two patients were normal. These observations together suggest that a high level of Y4RNAfr in peripheral blood plasma and a normal WBC could be indicative of multiple myeloma.

Impact of technically qualified surgeons on laparoscopic colorectal resection outcomes: results of a propensity score-matching analysis

Background

The Endoscopic Surgical Skill Qualification System (ESSQS) was introduced in Japan to improve the quality of laparoscopic surgery. This cohort study investigated the short‐ and long‐term postoperative outcomes of colorectal cancer laparoscopic procedures performed by or with qualified surgeons compared with outcomes for unqualified surgeons.

Methods

All laparoscopic colorectal resections performed from 2010 to 2013 in 11 Japanese hospitals were reviewed retrospectively. The procedures were categorized as performed by surgeons with or without the ESSQS qualification and patients' clinical, pathological and surgical features were used to match subgroups using propensity scoring. Outcome measures included postoperative and long‐term results.

Results

Overall, 1428 procedures were analysed; 586 procedures were performed with ESSQS‐qualified surgeons and 842 were done by ESSQS‐unqualified surgeons. Upon matching, two cohorts of 426 patients were selected for comparison of short‐term results. A prevalence of rectal resection (50·3 versus 40·5 per cent; P < 0·001) and shorter duration of surgery (230 versus 238 min; P = 0·045) was reported for the ESSQS group. Intraoperative and postoperative complication and reoperation rates were significantly lower in the ESSQS group than in the non‐ESSQS group (1·2 versus 3·6 per cent, P = 0·014; 4·6 versus 7·5 per cent, P = 0·025; 1·9 versus 3·9 per cent, P = 0·023, respectively). These findings were confirmed after propensity score matching. Cox regression analysis found that non‐attendance of ESSQS‐qualified surgeons (hazard ratio 12·30, 95 per cent c.i. 1·28 to 119·10; P = 0·038) was independently associated with local recurrence in patients with stage II disease.

Conclusion

Laparoscopic colorectal procedures performed with ESSQS‐qualified surgeons showed improved postoperative results. Further studies are needed to investigate the impact of the qualification on long‐term oncological outcomes.

P1512 Combination of mitral annular peak systolic and early diastolic velocities with early transmitral peak flow velocity: a new prognostic echo index in patients with acute coronary syndrome

Background

One of the novel echocardiographic indices reflecting left ventricular (LV) diastolic filling is the combination of mitral annular peak systolic (s’) and early diastolic velocities (e’) with early transmitral peak flow velocity (E); E/(e’ x s’). This index is reported to be useful to predict a prognosis of heart failure patients regardless of their LV ejection fraction (LVEF).Purpose: The aim of this study was to examine whether or not E/(e’ x s’) could predict cardiac events in patients with acute coronary syndrome (ACS).Methods: We studies consecutive ACS patients hospitalized in our institution between December 2009 and February 2012. They underwent echo examination within 7 days after admission. By use of Doppler tissue imaging, e’ and s’ were respectively calculated by averaging the peak velocities measured at both septal and lateral mitral annulus in 4-chamber view. The exclusion criteria were as follows: atrial fibrillation, significant valvular diseases and inadequate echo images. Cardiac events were defined as re-hospitalization due to recurrent ACS and/or heart failure, and cardiac mortality.Results: In total, 168 patients were eligible for this study (mean age 67 ± 11 years, mean LVEF 51.7 ± 10.3 %). Median follow-up period was 22.5 months. During the follow-up, cardiac events occurred in 27 patients (16.1%). Between the patients with cardiac events and those without, there were significant differences in LV end-systolic volume (44.2 ± 29.1 vs 33.2 ± 13.6 ml, p &lt; 0.05), LV mass index (122.4 ± 38.9 vs 107.5 ± 26.4 g/m², p &lt; 0.05), left atrial volume index (31.7 ± 9.2 vs 27.6 ± 9.4 ml/m², p &lt; 0.05), LVEF (45.7 ± 13.5 vs 52.9 ± 9.2 %, p &lt; 0.05), s’ (5.1 ± 1.6 vs 7.1 ± 1.7 cm/sec, p &lt; 0.001), e’ (4.8 ± 1.3 vs 6.0 ± 1.9 cm/sec, p &lt; 0.05), E/e’ (16.4 ± 6.6 vs 12.5 ± 4.9, p &lt; 0.05), E/(e’ x s’) (3.78 ± 2.52 vs 1.94 ± 1.08, p &lt; 0.001), and serum B-type natriuretic peptide (334.7 ± 420.1 vs 113.8 ± 177.2 pg/ml, p &lt; 0.05). While Cox proportional hazard multivariate analysis detected that E/(e’ x s’) and E/e’ were independent predictors of cardiac events, E/(e’ x s’) was more powerful than E/e’ (p = 0.0002 vs p = 0.0072). ROC analysis revealed that 2.35 of E/(e’ x s’) was the optimal cutoff values to predict cardiac events in ACS patients (AUC 0.79). Patients with E/(e’ x s’) &lt;2.35 had significantly better prognosis than the rest (p &lt; 0.0001, Log-rank; Figure)Conclusion: E/(e’ x s’) could be a useful echo marker to predict cardiac events in ACS patients.

Abstract P1512 Figure.

P1508 Left ventricular diastolic function plays a different role on mortality depending on the severity of systolic dysfunction in acute heart failure patients with reduced ejection fraction

Background

It remains to be clarified whether clinical significance of left ventricular (LV) diastolic function differs depending on the severity of LV systolic dysfunction in patients with acute heart failure (AHF). The aim of this study was to examine the prognostic role of LV diastolic function in AHF patients with various systolic dysfunction.Methods: We studied consecutive hospitalized AHF patients with LV ejection fraction (LVEF) &lt;50%. The exclusion criteria were as follows: atrial fibrillation, severe mitral regurgitation, and inadequate echo image quality. They underwent echocardiography on admission. The eligible patients (n = 289, 165 males, 76 ± 10 years) were divided into 4 groups based on LVEF and left atrial pressure (LAP) grade estimated as in the ESC guidelines: Group I (LVEF 40-49% (mildly reduced LVEF)/normal LAP, n = 28), II (mildly reduced EF/increased LAP, n = 38), III (LVEF &lt;40% (severely reduced LVEF)/normal LAP, n = 110), and IV (severely reduced LVEF/increased LAP, n = 113). Cardiac death was examined up to 60 months.Results: In total, 58 patients (20%) died because of cardiac events during the follow-up (mean 20 ± 19 months). In patients with mildly reduced LVEF, Group I showed significantly less cardiac death ratio than II (n = 1 vs 10, Group I vs II, p = 0.03). On the other hand, in patients with severely reduced LVEF, there was no significant difference in cardiac death ratio between Group III and IV (n = 23 vs 24, Group III vs IV, p = 0.80). That is, LAP grade was a prognostic marker when the patients had mild LV systolic dysfunction, whereas it did not contribute to the prediction of cardiac mortality when patients showed severely reduced LV systolic function. Group I showed significantly better prognosis than those with severe LV systolic dysfunction regardless of LAP grade (Group III, IV) (Group I vs III, p = 0.04; Group I vs IV, p = 0.04).Conclusions: LV diastolic function may have a different clinical significance depending on the severity of LV systolic dysfunction in AHF patients.

299 The prevalence and role of SCN10A variants in Han Chinese patients with Brugada syndrome: the SADS-TW BrS registry

On Behalf

SADS-TW BrS registry

Background

Brugada syndrome (BrS) is an inheritable arrhythmic disease responsible for sudden cardiac death. Information on the prevalence and role of SCN10A variants in BrS is limited and equivocal.

Purpose

We aimed to investigate the prevalence and role of SCN10A variants in BrS in Han Chinese.

Methods

From 2000 to 2017, we prospectively and consecutively enrolled 176 unrelated BrS patients from the Han Chinese population in Taiwan (the SADS-TW BrS registry). Thirty-four BrS-related genes were screened by next-generation sequencing, using Taiwan Biobank as the population reference. The pathogenicity was evaluated by literature review and in silico analyses, including the SKAT-O algorithm.

Results

The SKAT-O algorithm showed that rare variants of SCN10A, but not common variants, were significantly different between BrS patients and healthy controls in the additive and dominant models (p-value &lt;0.001), suggesting that rare SCN10A variants may play a role in BrS. Six likely pathogenic SCN10A variants were found in 6 patients and were compared to 25 pathogenic or likely pathogenic SCN5A variants found in 29 patients. The patients with likely pathogenic SCN10A variants tended to exhibit sudden death in older age and have a shorter QRS interval than those carrying pathogenic or likely pathogenic SCN5A variants or no variants in either gene (p = 0.06, 0.07, respectively). Collectively, the prevalence of likely pathogenic SCN10A variants was 3.4% in Han Chinese patients with BrS in Taiwan.

Conclusions

SCN10A likely pathogenic variants were present in 3.4% of Han Chinese BrS patients. Rare SCN10A variants may play a role in BrS, and may have impact on clinical and electrocardiographic manifestations.

Table 1. Patient Nucleotide Amino acid TWB gnomAD_EA REVEL CADD PHRED SIFT Polyphen-2 GERP++ 1 c.5789A &gt; T p.D1930V 0.001318 0.0008700 0.479 24.5 Damaging Possibly damaging 4.22 2 c.2341G &gt; A p.G781R 0 0.00005301 0.866 33 Damaging Probably damaging 4.83 3 c.5587C &gt; T p.R1863W 0.000502 0 0.832 27.8 Damaging Probably damaging 1.97 4 c.2161C &gt; T p.P721S 0.000989 0.0009016 0.933 28.5 Damaging Probably damaging 4.19 5 c.3749G &gt; A p.R1250Q 0 0 0.907 31 Damaging Probably damaging 4.23 6 c.1825A &gt; T p.R609W 0.000659 0.0001591 0.811 32 Damaging Probably damaging 4.28 Clinical and predicted functional characteristics of 6 likely pathogenic SCN10A variants. EA = East Asian; GERP = Genomic Evolutionary Rate Profiling; TWB = Taiwan Biobank. Transcript: NM_006514.3.

Abstract 299 Figure. Location of the SCN10A variants

Impact of spaceflight on the murine thymus and mitigation by exposure to artificial gravity during spaceflight

The environment experienced during spaceflight may impact the immune system and the thymus appears to undergo atrophy during spaceflight. However, molecular aspects of this thymic atrophy remain to be elucidated. In this study, we analysed the thymi of mice on board the international space station (ISS) for approximately 1 month. Thymic size was significantly reduced after spaceflight. Notably, exposure of mice to 1 × g using centrifugation cages in the ISS significantly mitigated the reduction in thymic size. Although spaceflight caused thymic atrophy, the global thymic structure was not largely changed. However, RNA sequencing analysis of the thymus showed significantly reduced expression of cell cycle-regulating genes in two independent spaceflight samples. These reductions were partially countered by 1 × g exposure during the space flights. Thus, our data suggest that spaceflight leads to reduced proliferation of thymic cells, thereby reducing the size of the thymus, and exposure to 1 × g might alleviate the impairment of thymus homeostasis induced by spaceflight.

Potential physiological roles of the 31/32-nucleotide Y4-RNA fragment in human plasma

The 31- and 32-nt 5′-fragments of Y4-RNA (Y4RNAfr) exist abundantly in human plasma. The Y4RNAfr can function as 5′-half-tRNA-type sgRNA for tRNase Z^L, although we do not know yet what its physiological roles are and what cellular RNAs are its genuine targets. In this paper, we analyzed the effects of the Y4RNAfr on cell viability and transcriptomes using HL60, RPMI-8226, and HEK293 cells, and Y4RNAfr-binding RNAs in A549 cells. Although the Y4RNAfr hardly affected the viability of HL60, RPMI-8226, and HEK293 cells, it significantly affected their transcriptome. The DAVID analysis for > 2-fold upregulated and downregulated genes suggested that the Y4RNAfr may affect various KEGG pathways. We obtained 108 Y4RNAfr-binding RNAs in A549 cells, searched potential secondary structures of complexes between theY4RNAfr and its binding RNAs for the pre-tRNA-like structure, and found many such structures. One of the five best fitted structures was for the MKI67 mRNA, suggesting that the Y4RNAfr can decrease the cellular MKI67 level through guiding the cleavage of the MKI67 mRNA by tRNase Z^L. This may be one of the underlying mechanisms for the reported observation that the Y4RNAfr suppresses the proliferation of A549 cells.