Clinical aspects of pediatric Brugada syndrome

Introduction

Brugada syndrome (BrS) is an inherited arrhythmia characterized by a coved-type ST elevation and sudden death, especially in middle-aged males and more common in Asia. Mutations in SCN5A are detected in 15–20% and reported to be associated with poor prognosis. Among children, BrS is rare and the risk factors in pediatric BrS are unknown, especially in Asian population.

Purpose

The purpose of this study is to elucidate the risk factors for fatal arrhythmic events in Japanese pediatric patients with BrS.

Methods

We enrolled 52 Japanese children with BrS younger than 20 years, and performed genetic analysis and collected the clinical information.

Results

The mean age of initial symptoms was 10.7±5.5 years, and the mean follow-up period was 3.9±5.5 years. Ninety percent of patients were probands. No subjective symptom was confirmed in 28 of the patients, but aborted cardiac arrest (ACA) in 4, ventricular tachycardia in 4, ventricular fibrillation in 1, and syncope in 11. We identified mutations in SCN5A in 63%. There was no significant gender difference in ≤10 years, but a significant male predominance appeared in >10 years. And no gender difference was confirmed in the incidence of severe cardiac events in ≤10 years.

Conclusion

No gender difference was confirmed in ≤10 years in this study about Asian children. And being girls did not reduce the risk in ≤10 years. The frequency of SCN5A mutations was higher than adults, but decreased from childhood (68%) to adolescence (59%). In BrS, genetical and environmental factors may be more effective in childhood and adulthood, respectively.

Funding Acknowledgement

Type of funding source: None

Comparison of clinical characteristics between patients with microvascular and epicardial coronary artery spasm

Background

Coronary functional abnormalities including both epicardial and microvascular coronary artery spasm represent an important role responsible for myocardial ischemia in patients with angina and nonobstructive coronary artery disease. However, clinical characteristics associated with microvascular spasm (MVS) have not been fully evaluated.

Purpose

The aim of this study was to assess differences in clinical features between patients with MVS and epicardial coronary spasm.

Methods

A total of 732 consecutive patients with suspected angina who presented nonobstructive coronary arteries and underwent intracoronary acetylcholine provocation test were retrospectively enrolled in this study. Epicardial coronary spasm was defined as total or subtotal occlusion of epicardial coronary arteries accompanied by chest pain and/or ischemic electrocardiographic changes in response to acetylcholine provocation test. MVS was diagnosed when chest pain and/or ischemic electrocardiographic changes developed after administration of acetylcholine in the absence of epicardial coronary spasm. Clinical characteristics were compared between patients with MVS and epicardial coronary spasm.

Results

Of all patients, 83 patients (11%) had MVS, 367 (50%) had epicardial coronary spasm, and the other patients (39%) showed neither MVS nor epicardial coronary spasm. Patients with MVS tended to be older (65.6±12.7 vs. 63.0±12.3 years, P=0.088) and were more frequently female (60.2% vs. 41.1%, P=0.0016) in comparison with patients with epicardial coronary spasm. Patients with MVS were less likely to be smokers (8.6% vs. 22.9%, P=0.0018), while there were no significant differences in the other coronary risk factors such as hypertension, dyslipidemia, and diabetes mellitus. Serum uric acid were significantly lower in patients with MVS (4.9±1.1 vs. 5.4±1.3 mg/dl, P=0.0018).

Conclusion

Our study demonstrated that patients with MVS had distinctive clinical background from those with epicardial coronary spasm, suggesting different mechanisms may involve the development of MVS.

Funding Acknowledgement

Type of funding source: None

Splice site mutation of LMNA causes severe dilated cardiomyopathy via strong dominant reduction of total lamin expression

Objective

LMNA is a known causative gene of dilated cardiomyopathy (DCM) and familial cardiac conduction disturbance (CCD). Genetic variants affecting the pre-mRNA splicing process often lead to premature stop codons and result in nonsense-mediated mRNA decay (NMD), followed by degradation of mutated alleles. The misssense variant LMNA c. 936G>C was previously reported in a French family affected by muscular dystrophy, CCD, and DCM, but no detailed analysis has been performed. We so far identified the same variant in two Japanese families affected by CCD and DCM. In this study, we investigated the molecular consequences of the variant located at the last codon of LMNA exon5 to demonstrate its pathogenicity.

Methods

Genomic DNA and total RNA were isolated from patients' peripheral blood lymphocytes or cardiac tissue. LMNA-coding exons were screened by direct sequencing. Complementary DNAs (cDNAs) were generated by reverse transcription PCR from RNA. Quantitative PCR (qPCR) was performed to quantify the LMNA cDNA amount by using specific primers for lamins A and C. The protein expressions of both isoforms were analyzed by western blotting.

Results

We detected the heterozygous LMNA c.936 G>C (p. Q312H) variant at the end of exon 5 by genomic DNA sequencing in two unrelated Japanese families (figure. pedigree) affected by DCM and CCD. In a genomic database survey, we did not find the variant in either gnomAD, TogoVar, or the Human Genetic Variation Database. The two commonly used splice site predictor tools, NetGene2 and FSPLICE, estimated that this site was a splice donor site. Sequencing of cDNA demonstrated that the mutated allele was absent. By qPCR assay, we confirmed a 90% reduction in LMNA cDNA. Western blot analysis revealed that lamin A and C expression was reduced far more than 50% (figure. western blot).

Conclusions

We report a LMNA missense mutation found in two families, which disrupts a normal splicing site, leads to NMD, and resulted in severe cardiac laminopathy. The drastic reductions of lamin expression at the cDNA and protein levels suggested that other co-existing mechanisms may also have suppressed the expression of the healthy wild type allele.

Pedigree and western blot assay

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science KAKENHI

Identification of two genes as novel susceptibility loci for type 2 diabetes mellitus in Japanese

Background

The heritability of Type 2 diabetes mellitus (T2DM) has been estimated to be 50% to 60%. Although genome-wide association studies identified >120 loci that confer susceptibility to T2DM, these studies were commonly conducted in a cross-sectional manner.

Purpose

The purpose of the study was to identify genetic variants that confer susceptibility to T2DM in Japanese. We have now performed longitudinal exome-wide association studies (EWASs) to identify novel loci for T2DM by examining temporal changes in fasting plasma glucose (FPG) level, blood hemoglobin A1c (HbA1c) content, and the prevalence of T2DM.

Methods

Longitudinal EWASs (mean follow-up period, 5 years) were performed with Illumina Human Exome-12 v1.2 DNA Analysis BeadChip or Infinium Exome-24 v1.0 BeadChip arrays and with 6,022 Japanese (755 subjects with T2DM, 5267 controls). The relation of genotypes of 24,579 SNPs that passed quality control to FPG level, blood HbA1c content, or the prevalence of T2DM was examined with the generalized estimating equation (GEE). To compensate for multiple comparisons of genotypes with each of the three parameters, we applied Bonferroni's correction for statistical significance of association.

Results

Longitudinal EWASs (GEE with adjustment for age, sex, body mass index, and smoking) revealed that rs6414624 of EVC (P<2.0×10–16 for T2DM, P=9.1×10–11 for FPG), rs78338345 of GGA3 (P<2.0×10–16 for T2DM, P=4.3×10–9 for FPG), rs10490775 of PTPRG (P<2.0×10–16 for T2DM, P=3.3×10–7 for FPG), and rs61739510 of GLT6D1 (P<2.0×10–16 for T2DM, P=5.8×10–7 for FPG) were significantly associated with the prevalence of T2DM and FPG levels; and rs11558471 in SLC30A8 with FPG level (P=1.8×10–8) and blood HbA1c content (P=1.2×10–7). After examination of the relation of identified SNPs to FPG level and blood HbA1c content, linkage disequilibrium of the SNPs, and results of the previous genome-wide association studies, we identified rs6414624 of EVC and rs78338345 of GGA3 as novel susceptibility loci for T2DM. In the identified SNPs (rs6414624 and rs7833834), FPG level, blood HbA1c content, and the prevalence of T2DM were significantly lower in homozygotes with the minor alleles than in homozygotes with the major alleles or heterozygotes. These results suggest that the minor alleles of rs6414624 and rs78338345 are protective against T2DM in Japanese. According to allele frequency data from the 1000 Genomes Project database, the minor G allele of rs78338345 of GGA3 is specifically distributed in East Asia. This suggests that the minor allele frequency may have increased in East Asian populations after the split of East Asian and non-East Asian populations.

Conclusion

We have newly identified EVC and GGA3 as susceptibility loci for T2DM in Japanese. Determination of genotypes for these SNPs at these loci may prove informative for assessment of the genetic risk for T2DM in Japanese.

Funding Acknowledgement

Type of funding source: None

Age-related differences and vascular function test findings in patients with vasospastic angina

Background

Vasospastic angina (VSA) accounts for the majority of angina cases with no epicardial stenosis and develops amongawide range of age, which is reportedly induced by coronary functional abnormalities including endothelial dysfunction and smooth muscle hypercontraction. However, the relation of noninvasive vascular function tests to VSA remains to be fully elucidated.

Purpose

The aim of this study was to assess differences in clinical characteristics and findings from noninvasive vascular function tests among groups by age in patients with VSA.

Methods

We enrolled a total of 732 patients with angina who underwent intracoronary acetylcholine provocation test. VSA was defined as total or subtotal occlusion of epicardial coronary arteries accompanied by chest pain and/or ischemic electrocardiographic changes in response to acetylcholine administration. Patients with VSA were divided into 3 groups by age (young [<50 years], intermediate [50–64 years], and elderly group [≥65 years]). Noninvasive vascular function test findings such as ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), andpercentage of mean arterial pressure (%MAP) were compared among groups by age in patients with VSA.

Results

Of all patients, 367 (50.1%) were diagnosed as VSA with intracoronary acetylcholine test, including 66 (18.0%), 113 (30.8%), and 188 (51.2%) patients in the young, intermediate, and elderly groups. Among groups by age, there was no significant difference in gender (female, 31.8% vs. 40.7% vs. 44.7%, P=0.19). Patients in the young group were more often smokers and alcohol drinkers than those in the intermediate and elderly groups, while the prevalence of hypertension, dyslipidemia, and diabetes were lower in younger patients. A history of percutaneous coronary intervention was less frequently found in the young group compared tothe intermediate and elderly groups (7.6% vs. 16.8% vs. 20.7%, P=0.033). The baPWV was higher in the elderly group (1424±232 vs. 1537±247 vs. 1774±358 cm/s, P<0.0001), while there was no difference in ABI between the 3 groups. %MAP at arms was significantly and progressively decreased with an increase in age (54.0±4.5% vs. 53.0±2.6% vs. 51.2±2.8%, P<0.0001).

Conclusion

Our study demonstrated that there were distinct age-related differences in clinical characteristics of patients with VSA. The higher %MAP in younger patients suggests that more impaired endothelial dysfunction may play a role in the development of VSA in this age group.

Funding Acknowledgement

Type of funding source: None

Exploratory open-label clinical study to determine the S-588410 cancer peptide vaccine-induced tumor-infiltrating lymphocytes and changes in the tumor microenvironment in esophageal cancer patients

Cancer vaccines induce cancer-specific T-cells capable of eradicating cancer cells. The impact of cancer peptide vaccines (CPV) on the tumor microenvironment (TME) remains unclear. S-588410 is a CPV comprising five human leukocyte antigen (HLA)-A*24:02-restricted peptides derived from five cancer testis antigens, DEPDC1, MPHOSPH1, URLC10, CDCA1 and KOC1, which are overexpressed in esophageal cancer. This exploratory study investigated the immunologic mechanism of action of subcutaneous S-588410 emulsified with MONTANIDE ISA51VG adjuvant (median: 5 doses) by analyzing the expression of immune-related molecules, cytotoxic T-lymphocyte (CTL) response and T-lymphocytes bearing peptide-specific T-cell receptor (TCR) sequencing in tumor tissue or blood samples from 15 participants with HLA-A*24:02-positive esophageal cancer. Densities of CD8+, CD8+ Granzyme B+, CD8+ programmed death-1-positive (PD-1+) and programmed death-ligand 1-positive (PD-L1+) cells were higher in post- versus pre-vaccination tumor tissue. CTL response was induced in all patients for at least one of five peptides. The same sequences of peptide-specific TCRs were identified in post-vaccination T-lymphocytes derived from both tumor tissue and blood, suggesting that functional peptide-specific CTLs infiltrate tumor tissue after vaccination. Twelve (80%) participants had treatment-related adverse events (AEs). Injection site reaction was the most frequently reported AE (grade 1, n = 1; grade 2, n = 11). In conclusion, S-588410 induces a tumor immune response in esophageal cancer. Induction of CD8+ PD-1+ tumor-infiltrating lymphocytes and PD-L1 expression in the TME by vaccination suggests S-588410 in combination with anti-PD-(L)1 antibodies may offer a clinically useful therapy.Trial registration UMIN-CTR registration identifier: UMIN000023324.

Exposure to Asian dust within a few days of delivery is associated with placental abruption in Japan: a case-crossover study

OBJECTIVE

Asian dust is a natural phenomenon in which dust particles are transported from desert areas in China and Mongolia to East Asia. Short-term exposure to Asian dust has been associated with cardiovascular disease through mechanisms such as systemic inflammation. Because inflammation is a potential trigger of placental abruption, exposure may also lead to abruption. We examined whether exposure to Asian dust was associated with abruption.

DESIGN

A bi-directional, time-stratified case-crossover design.

SETTING AND POPULATION

From the Japan Perinatal Registry Network database, we identified 3014 patients who delivered singleton births in hospitals in nine Japanese prefectures from 2009 to 2014 with a diagnosis of placental abruption.

METHODS

Asian dust levels were measured at Light Detection and Ranging monitoring stations, and these measurements were used to define the Asian dust days. As there was no information on the onset day of abruption, we assumed this day was the day before delivery (lag1).

MAIN OUTCOME MEASURES

Placental abruption.

RESULTS

During the study period, the Asian dust days ranged from 15 to 71 days, depending on the prefecture. The adjusted odds ratio of placental abruption associated with exposure to Asian dust was 1.4 (95% confidence interval = 1.0, 2.0) for cumulative lags of 1-2 days. Even after adjustment for co-pollutant exposures, this association did not change substantially.

CONCLUSIONS

In this Japanese multi-area study, exposure to Asian dust was associated with an increased risk of placental abruption.

TWEETABLE ABSTRACT

Exposure to environmental factors such as Asian dust may be a trigger of placental abruption.

Evaluation of Deep Thermal Rehabilitation System Using Resonant Cavity Applicator During Knee Experiments

This paper evaluates experiments on the knee using a new heating rehabilitation system. For effective thermal rehabilitation of osteoarthritis, it is necessary to heat the deep tissue inside the knee joint. Our new rehabilitation system is based on the re-entrant type resonant cavity applicator which was developed for deep hyperthermia treatment in our previous studies. Our experimental results using agar phantoms showed our heating system is able to heat the deep tissue inside the knee without physically contacting the surface skin. In this study, we developed a prototype applicator and experimented on a healthy human subject's knee under clinical conditions. To evaluate heating performance, we conducted heating experiments with our resonant cavity applicator and a conventional microwave diathermy system and compared the results. The experimental results of temperature increase distributions inside the human body were estimated by ultrasound imaging techniques. The estimated results from our knee experiments show that our heating system is able to heat knee tissue more deeply than microwave diathermy systems can and thus would be effective for deep thermal rehabilitation applications in clinics.

Bacterial co-infection and early mortality among pulmonary tuberculosis patients in Manila, The Philippines

OBJECTIVE

To investigate the prevalence of bacterial co-infection and its effect on early mortality among hospitalised human immunodeficiency virus (HIV) negative pulmonary tuberculosis (PTB) patients in Manila, the Philippines.

DESIGN

A prospective observational study was conducted at a national infectious disease hospital. HIV-negative PTB patients aged 13 years hospitalised from November to December 2011 and from December 2012 to May 2013 were enrolled. Sputum samples were tested for Mycobacterium tuberculosis and six respiratory bacterial pathogens using polymerase chain reaction (PCR).

RESULTS

Of 466 patients, 228 (48.9%) were TB-PCR-positive. Overall, bacterial pathogens in purulent sputum were detected in 135 (29.0%) patients: Haemophilus influenzae was the most common bacterium (21.2%), followed by Streptococcus pneumoniae (7.9%). The prevalence of bacterial co-infection did not differ between TB-PCR-positive and -negative patients. A total of 92 (19.7%) patients died within 2 weeks. Bacterial co-infection was significantly associated with an increased risk of 2-week mortality among TB-PCR-positive patients (adjusted risk ratio [aRR] 1.67, 95%CI 1.03-2.72). This association was also observed but did not reach statistical significance among TB-PCR-negative patients (aRR1.7, 95%CI 0.95-3.02).

CONCLUSION

Bacterial co-infection is common and contributes to an increased risk of early mortality among HIV-negative PTB patients.

P1542Identification of 13 novel susceptibility loci for early-onset myocardial infarction, hypertension, or chronic kidney disease in Japanese

Background

Early-onset cardiovascular and renal diseases have a strong genetic component.

Purpose

To identify genetic variants that confer susceptibility to early-onset myocardial infarction (MI), hypertension, or chronic kidney disease (CKD) in Japanese. We have performed exome-wide association studies (EWASs) in subjects with early-onset forms of these diseases.

Methods

A total of 8093 individuals aged ≤65 years was enrolled in the study. The EWASs for MI, hypertension, and CKD were conducted with 6926 subjects (1152 cases, 5774 controls), 8080 subjects (3444 cases, 4636 controls), and 2556 subjects (1051 cases, 1505 controls), respectively. Genotyping of single nucleotide polymorphisms (SNPs) was performed with Illumina Human Exome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The relation of allele frequencies for 31,245, 31,276, or 31,514 SNPs that passed quality control to MI, hypertension, and CKD, respectively, was examined with Fisher's exact test. Bonferroni's correction for statistical significance of association was applied to compensate for multiple comparisons of genotypes with MI, hypertension, or CKD.

Results

The EWASs of allele frequencies revealed that 25, 11, and 11 SNPs were significantly associated with MI (P<1.60 × 10–6), hypertension (P<1.60 × 10–6), or CKD (P<1.59 × 10–6), respectively. Multivariable logistic regression analysis with adjustment for covariates showed that all 25, 11, and 11 SNPs were significantly related to MI (P<0.0005), hypertension (P<0.0011), or CKD (P<0.0011), respectively. After examination of results from previous genome-wide association studies and linkage disequilibrium of the identified SNPs, we newly identified 11 loci (TMOD4, COL6A3, ADGRL3-CXCL8-MARCH1, OR52E4, TCHP-GIT2, CCDC63, 12q24.1, OAS3, PLCB2-VPS33B, GOSR2, ZNF77), six loci (MOB3C-TMOD4, COL6A3, COL6A5, CXCL8-MARCH1, NFKBIL1-6p21.3-NCR3, PLCB2-VPS33B), and seven loci (MOB3C-TMOD4, COL6A3, COL6A5, ADGRL3-CXCL8-MARCH1, MUC17, PLCB2-VPS33B, ZNF77) that were significantly associated with MI, hypertension, or CKD, respectively. Furthermore, six genes (TMOD4, COL6A3, CXCL8, MARCH1, PLCB2, VPS33B) were significantly associated with MI, hypertension, and CKD; two genes (ADGRL3, ZNF77) with MI and CKD; and two genes (COL6A5, MOB3C) with hypertension and CKD. Network analysis showed that the 13, 10, or 11 genes associated with MI, hypertension, or CKD, respectively, in the present study had direct or indirect interactions with the corresponding sets of 50 genes previously shown to be associated with MI, hypertension, or CKD.

Conclusion

We newly identified 13 loci (MOB3C-TMOD4, COL6A3, ADGRL3-CXCL8-MARCH1, OR52E4, TCHP-GIT2, CCDC63, 12q24.1, OAS3, PLCB2-VPS33B, ZNF77, COL6A5, NFKBIL1-NCR3, MUC17) that confer susceptibility to early-onset MI, hypertension, or CKD. Determination of genotypes for the SNPs at these loci may prove informative for assessment of the genetic risk for MI, hypertension, or CKD in Japanese.

P3718Identification of nine genes as novel susceptibility loci for early-onset ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage

Background

Given that substantial genetic components have been shown in ischemic stroke, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH), a heritability may be higher in early-onset than late-onset individuals with these conditions. Although genome-wide association studies have identified various genes and loci significantly associated with ischemic stroke, ICH, or intracranial aneurysm mainly in European ancestry populations, genetic variants that contribute to susceptibility to these disorders in Japanese individuals remain to be identified definitively.

Purpose

The purpose of the study was to identify genetic variants that confer susceptibility to ischemic stroke, ICH, or SAH in Japanese. We have now performed exome-wide association studies (EWASs) in early-onset subjects with these conditions and corresponding controls.

Methods

A total of 6649 individuals aged ≤65 years were examined. For the EWAS of ischemic or hemorrhagic stroke, 6224 individuals (450 subjects with ischemic stroke, 5774 controls) or 6179 individuals (261 subjects with ICH, 176 subjects with SAH, 5742 controls), respectively, were examined. EWASs were performed with the use of Illumina Human Exome-12 v1.2 DNA Analysis BeadChip or Infinium Exome-24 v1.0 BeadChip. To compensate for multiple comparisons of allele frequencies with ischemic stroke, ICH, or SAH, we applied a false discovery rate (FDR) of <0.05 for statistical significance of association.

Results

The relation of allele frequencies of 31,245 single nucleotide polymorphisms (SNPs) that passed quality control to ischemic stroke was examined with Fisher's exact test, and 31 SNPs were significantly (FDR <0.05) associated with ischemic stroke. The relation of allele frequencies of 31,253 or 30,970 SNPs to ICH or SAH, respectively, was examined with Fisher's exact test, and six or two SNPs were significantly (FDR <0.05) associated with ICH or SAH, respectively. Multivariable logistic regression analysis with adjustment for age, sex, and the prevalence of hypertension and diabetes mellitus revealed that 12 SNPs were significantly [P <0.0004 (Bonferroni's correction, 0.05/124)] related to ischemic stroke. Similar analysis with adjustment for age, sex, and the prevalence of hypertension revealed that six or two SNPs were significantly [P <0.0016 (0.05/32)] related to ICH or SAH, respectively. After examination of linkage disequilibrium of identified SNPs and results of previous genome-wide association studies, we have newly identified HHIPL2, CTNNA3, LOC643770, UTP20, and TRIB3 as susceptibility loci for ischemic stroke, DNTTIP2 and FAM205A as susceptibility loci for ICH, and FAM160A1 and OR52E4 as such loci for SAH.

Conclusion

We have thus newly identified nine genes that confer susceptibility to early-onset ischemic stroke, ICH, or SAH. Determination of genotypes for the SNPs in these genes may prove informative for assessment of the genetic risk for ischemic stroke, ICH, or SAH in Japanese.