Identification of Prostaglandin I2 Synthase Rare Variants in Patients With Williams Syndrome and Severe Peripheral Pulmonary Stenosis

BACKGROUND

Peripheral pulmonary stenosis (PPS) is a condition characterized by the narrowing of the pulmonary arteries, which impairs blood flow to the lung. The mechanisms underlying PPS pathogenesis remain unclear. Thus, the aim of this study was to investigate the genetic background of patients with severe PPS to elucidate the pathogenesis of this condition.

METHODS AND RESULTS

We performed genetic testing and functional analyses on a pediatric patient with PPS and Williams syndrome (WS), followed by genetic testing on 12 patients with WS and mild-to-severe PPS, 50 patients with WS but not PPS, and 21 patients with severe PPS but not WS. Whole-exome sequencing identified a rare PTGIS nonsense variant (p.E314X) in a patient with WS and severe PPS. Prostaglandin I2 synthase (PTGIS) expression was significantly downregulated and cell proliferation and migration rates were significantly increased in cells transfected with the PTGIS p.E314X variant-encoding construct when compared with that in cells transfected with the wild-type PTGIS-encoding construct. p.E314X reduced the tube formation ability in human pulmonary artery endothelial cells and caspase 3/7 activity in both human pulmonary artery endothelial cells and human pulmonary artery smooth muscle cells. Compared with healthy controls, patients with PPS exhibited downregulated pulmonary artery endothelial prostaglandin I2 synthase levels and urinary prostaglandin I metabolite levels. We identified another PTGIS rare splice-site variant (c.1358+2T>C) in another pediatric patient with WS and severe PPS.

CONCLUSIONS

In total, 2 rare nonsense/splice-site PTGIS variants were identified in 2 pediatric patients with WS and severe PPS. PTGIS variants may be involved in PPS pathogenesis, and PTGIS represents an effective therapeutic target.

Animal Disease Models and Patient-iPS-Cell-Derived In Vitro Disease Models for Cardiovascular Biology-How Close to Disease?

Currently, zebrafish, rodents, canines, and pigs are the primary disease models used in cardiovascular research. In general, larger animals have more physiological similarities to humans, making better disease models. However, they can have restricted or limited use because they are difficult to handle and maintain. Moreover, animal welfare laws regulate the use of experimental animals. Different species have different mechanisms of disease onset. Organs in each animal species have different characteristics depending on their evolutionary history and living environment. For example, mice have higher heart rates than humans. Nonetheless, preclinical studies have used animals to evaluate the safety and efficacy of human drugs because no other complementary method exists. Hence, we need to evaluate the similarities and differences in disease mechanisms between humans and experimental animals. The translation of animal data to humans contributes to eliminating the gap between these two. In vitro disease models have been used as another alternative for human disease models since the discovery of induced pluripotent stem cells (iPSCs). Human cardiomyocytes have been generated from patient-derived iPSCs, which are genetically identical to the derived patients. Researchers have attempted to develop in vivo mimicking 3D culture systems. In this review, we explore the possible uses of animal disease models, iPSC-derived in vitro disease models, humanized animals, and the recent challenges of machine learning. The combination of these methods will make disease models more similar to human disease.

Systematic in vitro metabolic profiling of the OXIZID synthetic cannabinoids BZO-4en-POXIZID, BZO-POXIZID, 5F-BZO-POXIZID, BZO-HEXOXIZID and BZO-CHMOXIZID

The new class of synthetic cannabinoids termed OXIZIDs has recently emerged on the recreational drug market. In order to continue detection of new drugs in biological specimens, identification of metabolites is essential. The aim of this study was to elucidate the metabolites of BZO-4en-POXIZID produced in human liver microsomes (HLM) and human hepatocyte incubations and to compare the results with closely related analogs using the same experimental setup. Each drug was incubated for 1 h in HLM and BZO-4en-POXIZID was also incubated in human hepatocytes for up to 3 h. Subsequently, the incubates were analyzed by liquid chromatography-high-resolution mass spectrometry. BZO-4en-POXIZID metabolites were obtained in the incubation with HLM and human hepatocytes, via the metabolic pathways of dihydrodiol formation, hydroxylation, reduction of the alkene bond, and glucuronidation. The major metabolic pathway was found to be dihydrodiol formation at the pentenyl tail moiety. BZO-POXIZID, 5F-BZO-POXIZID, BZO-HEXOXIZID and BZO-CHMOXIZID underwent similar metabolism to those reported in the literature, via the metabolic pathways of N-dealkylation, hydroxylation, ketone formation, and oxidative defluorination (to alcohol or carboxylic acid). The results suggest that OXIZIDs are mainly metabolized at the N-alkyl moiety and the major metabolic pathways are hydroxylation when the N-alkyl moiety is a simple hydrocarbon, whereas functional-group-specific pathways (dihydrodiol formation and oxidative defluorination) are preferred when the moiety contains specific functional groups (alkene or fluoro), as has been observed for other synthetic cannabinoids. The major metabolites generated via these major metabolic pathways should serve as useful analytical targets for urine analysis. Furthermore, the higher abundance of glucuronidated metabolite suggests that enzymatic hydrolysis of glucuronides may be necessary in urine analysis to increase phase I metabolite concentration and improve detection.

Forensic Discrimination of Drug Powder Based on Drug Mixing Condition Determined Using Micro Fourier Transform Infrared Spectroscopy

The quantitative evaluation of the drug mixing condition was conducted for application in the forensic discrimination of drug powders using micro Fourier transform infrared (FT-IR) spectroscopy. Bromhexine hydrochloride (BHCl) and p-hydroxybenzoic acid (PHBA) were used as the simulated drug and additive, respectively. Equal masses of two chemicals were (1) simply mixed, (2) homogenized using agate mortar, or (3) dissolved in methanol and dried, and then (4) homogenized using agate mortar. The mixed powders dispersed on BaF₂ plates were subjected to mapping analysis of micro FT-IR spectroscopy using synchrotron radiation (SR) or globar light in transmission mode with aperture sizes of 2.5 x 2.5 and 10 x 10μm², and x-y scanning steps of 2.5 and 10 μm, respectively. The areas of the vibration bands specific to BHCl (C-N bending) and PHBA (C=O stretching) were converted to the molar contents (C_BHCl, C_PHBA), and the relative content ratio (RCR: C_PHBA/[C_BHCl + C_PHBA]) was used as one mixing parameter. The resulting two-dimensional distribution map provided the relative spatial localizations of the two species, and frequency histograms with a horizontal axis of RCR were plotted to evaluate the RCR distribution. The percentage frequency of the extreme value in which RCR was 0 or 1 (%EV) was used as one mixing index. After excluding the extreme values, the coefficient of variation (CV) of the RCR distribution was used as another mixing index. The differentiation among four mixing modes could be evaluated from the standpoint of %EV and CV, and the discrimination capacity by SR instrument was superior to that by globe light instrument.

Predictors of liver cirrhosis and hepatocellular carcinoma among perioperative survivors of the Fontan operation

OBJECTIVE

Fontan-associated liver disease (FALD) is widely recognised as a common complication in patients long after the Fontan operation. However, data on the predictors of FALD that can guide its screening and management are lacking. The present study aimed to identify the predictors of liver cirrhosis (LC) and hepatocellular carcinoma (HCC) in post-Fontan patients.

METHODS

This was a multi-institutional retrospective cohort study. Clinical data of all perioperative survivors of Fontan operation before 2011 who underwent postoperative catheterisation were collected through a retrospective chart review.

RESULTS

A total of 1117 patients (538 women, 48.2%) underwent their first Fontan operation at a median age of 3.4 years. Postoperative cardiac catheterisation was conducted at a median of 1.0 year. During a median follow-up period of 10.3 years, 67 patients (6.0%) died; 181 (16.2%) were diagnosed with liver fibrosis, 67 (6.0%) with LC, 54 (4.8%) with focal nodular hyperplasia and 7 (0.6%) with HCC. On multivariable analysis, high central venous pressure (CVP) (HR, 1.28 (95% CI 1.01 to 1.63) per 3 mm Hg; p=0.042) and severe atrioventricular valve regurgitation (HR, 6.02 (95% CI 1.53 to 23.77); p=0.010) at the postoperative catheterisation were identified as independent predictors of LC/HCC.

CONCLUSIONS

Patients with high CVP and/or severe atrioventricular valve regurgitation approximately 1 year after the Fontan operation are at increased risk of developing advanced liver disease in the long term. Whether therapeutic interventions to reduce CVP and atrioventricular valve regurgitation decrease the incidence of advanced liver disease requires further elucidation.

The role of discrimination in the relation between COVID-19 sequelae, psychological distress, and work impairment in COVID-19 survivors

Perceived discrimination and work impairment are commonly observed in COVID-19 survivors, but their relationship has not been well understood. We aimed to evaluate the role of discrimination in the development of psychological distress and work impairment in COVID-19 survivors. From April 2020 to November 2021, 309 patients were recruited at two designated COVID-19 hospitals in Japan. Participants completed a standardized questionnaire including COVID-19 sequelae, psychological distress, impairments in work performance and perceived discrimination. The majority of participants (62.5%) experienced one or more COVID-19 sequelae. Psychological distress was observed in 36.9% and work impairment in 37.9%. In multivariate logistic regression analyses, COVID-19 sequelae and discrimination were associated with both psychological distress and work impairment. Mediation analysis demonstrated that the direct effect of sequelae on work impairment was non-significant after accounting for psychological distress, suggesting that the effect of sequelae on work impairment was mainly mediated through psychological distress. These findings were replicated in a subgroup analysis limited to patients with mild COVID-19. We conclude that discrimination plays an important role in the development of psychological distress and work impairment, and that both discrimination and psychological distress should be targets of intervention in COVID-19 survivors.

Effects of Machine Washing on the Chromatography Parameters of Polyester Fiber Gel Permeation

Fiber examination is frequently performed in forensics, and gel permeation chromatography (GPC) is one candidate method for discriminating polyester fibers. Here, the effects of machine washing on weight-average molecular weight (M _w), polydispersity index (PDI), and the percentage peak area of cyclic ethylene terephthalate trimer (PPAL) of commercial polyester shirts and manufactured poly(ethylene terephthalate) (PET) yarns were investigated using GPC. GPC was performed using a 1,1,1,3,3,3-hexafluoro-propan-2-ol polymer solubilizer, styrene-divinylbenzene copolymer GPC columns, a chloroform mobile phase, and a 254 nm absorbance monitor. The statistical change in the polyester fibers during machine washing was evaluated by comparing three GPC parameters of the same fiber samples before and after machine washing. Among the commercial polyester shirts examined, the GPC parameters changed significantly after machine washing with a considerable PPAL decrease. In contrast, the GPC parameters of manufactured PET yarns changed significantly with a moderate increase in M _w. This work elucidates the change on GPC parameters of polyester fibers by machine washing.

Long COVID occurrence in COVID-19 survivors

This cross-sectional study aimed to investigate the post-acute consequences of COVID-19. We conducted a self-administered questionnaire survey on sequelae, psychological distress (K6), impairments in work performance (WFun), and COVID-19-related experiences of stigma and discrimination in two designated COVID-19 hospitals in Hiroshima Prefecture, Japan, between August 2020 and March 2021. The prevalence of sequelae was calculated by age and COVID-19 severity. Factors independently associated with sequelae or psychological distress were identified using logistic regression analysis. Among 127 patients who had recovered from COVID-19, 52.0% had persistent symptoms at a median of 29 days [IQR 23-128] after COVID-19 onset. Among patients with mild COVID-19, 49.5% had sequelae. The most frequent symptoms were olfactory disorders (15.0%), taste disorders (14.2%), and cough (14.2%). Multivariate analysis showed that age was an independent risk factor for sequelae (adjusted odds ratios [AOR] for ≥ 60 years vs. < 40 years 3.63, p = 0.0165). Possible psychological distress was noted in 30.7% (17.9% of males and 45.0% of females). Female sex and the presence of sequelae were independent risk factors for psychological distress. Of all participants, 29.1% had possible impairments in work performance. Experiences of stigma and discrimination were reported by 43.3% of participants. This study revealed the significant impacts of Long COVID on health in local communities. A large-scale, long-term cohort study is desired.

Functional Evaluation of Human Bioengineered Cardiac Tissue Using iPS Cells Derived from a Patient with Lamin Variant Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is caused by various gene variants and characterized by systolic dysfunction. Lamin variants have been reported to have a poor prognosis. Medical and device therapies are not sufficient to improve the prognosis of DCM with the lamin variants. Recently, induced pluripotent stem (iPS) cells have been used for research on genetic disorders. However, few studies have evaluated the contractile function of cardiac tissue with lamin variants. The aim of this study was to elucidate the function of cardiac cell sheet tissue derived from patients with lamin variant DCM. iPS cells were generated from a patient with lamin A/C (LMNA) -mutant DCM (LMNA p.R225X mutation). After cardiac differentiation and purification, cardiac cell sheets that were fabricated through cultivation on a temperature-responsive culture dish were transferred to the surface of the fibrin gel, and the contractile force was measured. The contractile force and maximum contraction velocity, but not the maximum relaxation velocity, were significantly decreased in cardiac cell sheet tissue with the lamin variant. A qRT-PCR analysis revealed that mRNA expression of some contractile proteins, cardiac transcription factors, Ca²⁺-handling genes, and ion channels were downregulated in cardiac tissue with the lamin variant.Human iPS-derived bioengineered cardiac tissue with the LMNA p.R225X mutation has the functional properties of systolic dysfunction and may be a promising tissue model for understanding the underlying mechanisms of DCM.

Outcomes of Dilated Cardiomyopathy in Japanese Children - A Retrospective Cohort Study

BACKGROUND

There has been no nationwide survey on the prognosis of pediatric dilated cardiomyopathy (DCM) in Japan. Therefore, we designed this retrospective multicenter study to investigate the long-term survival rate in pediatric patients with DCM in Japan.Methods and Results:In this multicenter retrospective observational study, data were reviewed for 106 patients aged <18 years who had been diagnosed with DCM at any 1 of 18 Japanese institutions between 1990 and 2014. The median age at diagnosis was 2.0 years and the median duration of observation was 3.3 years. Most DCM patients were diagnosed because of symptoms of heart failure. On echocardiography, the median left ventricular end-diastolic dimension z score was 5.4 and fractional shortening was 0.10. Freedom from death or transplantation rates at 1, 3, 5, 10, and 20 years after diagnosis were 76%, 66%, 64%, 58%, and 43%, respectively. Freedom from death rates at 1, 5, 10, and 20 years after diagnosis were 81%, 75%, 72%, and 53%, respectively. The incidence of heart transplantation at 1, 5, 10, and 20 years after diagnosis was 6%, 15%, 20%, and 20%, respectively, suggesting that only 15% of patients in Japan underwent heart transplantation within 5 years of diagnosis.

CONCLUSIONS

In Japan, the prognosis of pediatric DCM is poor and the rate of heart transplantation is low.

Outcomes of Restrictive Cardiomyopathy in Japanese Children - A Retrospective Cohort Study

BACKGROUND

There has been no nationwide survey on the prognosis of pediatric restrictive cardiomyopathy (RCM) in Japan; therefore, this retrospective multicentered study was designed to investigate the long-term survival rate of pediatric patients with RCM in Japan.Methods and Results:A multicentered, retrospective observational study was performed between 1990 and 2014 and included patients diagnosed with RCM who were aged <18 years from 18 Japanese institutions. A total of 54 patients were diagnosed with RCM. The median age at diagnosis was 4.4 years, and the median duration of observation was 2.2 years at the time of this study. Of these patients, 54% had symptoms, including heart failure. Twelve patients died without heart transplantation, mostly due to heart failure. The median time to death from diagnosis was 2.5 years. Freedom from death at 1, 5, and 10 years was 91%, 68%, and 62%, respectively. Death occurred within 5 years of diagnosis in most patients. Twenty-two patients underwent heart transplantation. Freedom from heart transplantation at 1, 5, and 10 years was 77%, 58%, and 53%, respectively. Freedom from death or heart transplantation at 1, 5, and 10 years was 72%, 40%, and 34%, respectively. The presence of symptoms was a risk factor for death or transplantation.

CONCLUSIONS

The prognosis of pediatric RCM is poor, and the heart transplantation rate is low in Japan.

Predictors of long-term mortality among perioperative survivors of Fontan operation

AIMS

The criteria for 'good' Fontan haemodynamics have been poorly defined in relation to long-term outcomes. The aim of this study was to identify the risk factors for mortality among haemodynamic parameters obtained early after the Fontan operation.

METHODS AND RESULTS

Clinical data of all perioperative survivors of the Fontan operation performed before 2011, from nine institutions, were collected through a retrospective chart review. In total, 1260 patients were included. The median age at the time of Fontan operation was 3.6 years. Post-operative cardiac catheterization was conducted in 1117 patients at a median period of 1.0 years after the operation. During the median follow-up period of 10.2 years, 107 patients died. The mortality rates at 10, 20, and 25 years after the operation were 5%, 12%, and 22%, respectively. On multivariable analysis, older age at the time of the operation {≥15 years, hazard ratio (HR) [95% confidence interval (CI)]: 3.2 (1.7-5.9)} and haemodynamic parameters obtained at post-operative catheterization, such as low ejection fraction [<30%, HR (95% CI): 7.5 (3.2-18)], low systemic oxygen saturation [<80%, HR (95% CI): 3.8 (1.6-9.1)], high central venous pressure [≥16 mmHg, HR (95% CI): 2.3 (1.3-3.9)], and low mean systemic arterial pressure [<60 mmHg, HR (95% CI): 3.0 (1.4-6.2)] were identified as independent predictors of mortality. The predictive model based on these parameters had a c-index of 0.75 at 10 years.

CONCLUSIONS

Haemodynamic parameters obtained at a median period of 1.0 years, post-operatively, can accurately identify patients with a high mortality risk, who may need intensive management to improve long-term outcomes.

KEY QUESTION

What defines 'worse' Fontan haemodynamics?

KEY FINDING

Older age at Fontan (≥15 years), low ejection fraction (<30%), low oxygen saturation (<80%), high central venous pressure (≥16 mmHg), and low mean systemic arterial pressure (<60 mmHg) were identified as independent predictors of mortality.

TAKE HOME MESSAGE

Haemodynamic parameters obtained at a median period of 1.0 years, post-operatively, can accurately identify patients with a high mortality risk, who may need intensive management to improve long-term outcomes.

Induced Pluripotent Stem Cell-Derived Cardiomyocytes with SCN5A R1623Q Mutation Associated with Severe Long QT Syndrome in Fetuses and Neonates Recapitulates Pathophysiological Phenotypes

Simple Summary

In this study, the induced pluripotent stem cell-derived cardiomyocyte model from a patient with long QT syndrome harboring a heterozygous Nav1.5 R1623Q mutation exhibited prolonged field potential duration corrected by Fridericia’s formula (FPDcF, analogous to QTcF). FPDcF was shortened with mexiletine treatment and increased the frequency of arrhythmia-like EAD events following E4031, an I_kr blocker, administration. These characteristics partly reflect the patient phenotypes. As the R1623Q mutation is related to severe congenital LQT syndrome in fetuses and neonates, the effect of the neonatal variants on the electrophysiological properties of the R1623Q mutant was examined using an automated patch-clamp system. Our results demonstrated that both R1623Q and neonatal R1623Q delayed inactivation of I_Na and increased late Na current. We speculated that neonatal Nav1.5 ameliorates QTc prolongation. Developmental switching of neonatal/adult Nav1.5 isoforms might play a role in the mechanisms underlying severe long QT syndrome in fetuses and neonates.

Abstract

The SCN5A R1623Q mutation is one of the most common genetic variants associated with severe congenital long QT syndrome 3 (LQT3) in fetal and neonatal patients. To investigate the properties of the R1623Q mutation, we established an induced pluripotent stem cell (iPSC) cardiomyocyte (CM) model from a patient with LQTS harboring a heterozygous R1623Q mutation. The properties and pharmacological responses of iPSC-CMs were characterized using a multi-electrode array system. The biophysical characteristic analysis revealed that R1623Q increased open probability and persistent currents of sodium channel, indicating a gain-of-function mutation. In the pharmacological study, mexiletine shortened FPDcF in R1623Q-iPSC-CMs, which exhibited prolonged field potential duration corrected by Fridericia’s formula (FPDcF, analogous to QTcF). Meanwhile, E4031, a specific inhibitor of human ether-a-go-go-related gene (hERG) channel, significantly increased the frequency of arrhythmia-like early after depolarization (EAD) events. These characteristics partly reflect the patient phenotypes. To further analyze the effect of neonatal isoform, which is predominantly expressed in the fetal period, on the R1623Q mutant properties, we transfected adult form and neonatal isoform SCN5A of control and R1623Q mutant SCN5A genes to 293T cells. Whole-cell automated patch-clamp recordings revealed that R1623Q increased persistent Na⁺ currents, indicating a gain-of-function mutation. Our findings demonstrate the utility of LQT3-associated R1623Q mutation-harboring iPSC-CMs for assessing pharmacological responses to therapeutic drugs and improving treatment efficacy. Furthermore, developmental switching of neonatal/adult Nav1.5 isoforms may be involved in the pathological mechanisms underlying severe long QT syndrome in fetuses and neonates.

Complete remission from post-heart transplant lymphoproliferative disorder: A case report

We report a case of Burkitt's lymphoma, post-transplant lymphoproliferative disorder (BL-PTLD) that was treated with intensive chemotherapy. The patient was a 4-year-old boy who underwent heart transplantation at 7 months of age for refractory heart failure due to dilated cardiomyopathy. He was admitted to our hospital with a chief complaint of abdominal pain associated with an abdominal mass. Computed tomography was notable for a bulky mass arising from the terminal ileum. Fluorodeoxyglucose-positron emission tomography revealed multiple lesions in brain, bone, and lymph nodes. He was diagnosed with BL-PTLD stage III by pathological and clinical scoring. He was Epstein-Barr virus (EBV)-seronegative with a low EBV viral DNA load. No EBV-encoded small RNAs were in his intra-abdominal lymph nodes by in situ hybridization. On cytogenetic examination, the intra-abdominal lymph nodes revealed both a MYC rearrangement and a t(8;14)(q24;32), t(16;19)(q24;q13.1) translocation. Administration of tacrolimus and mycophenolate mofetil was discontinued; immunosuppression was maintained with everolimus. Intensive chemotherapy based on the modified LMB 96 protocol for BL was initiated, resulting in complete remission achieved. During the intensive chemotherapy and immunosuppressive switching period, cardiac dysfunction and allograft rejection had not been shown. The patient has remained well for two years after the treatment with no evidence of relapse. <Learning objective: Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication that can develop after heart transplantation and result in significant morbidity and mortality. In the case presented here, intensive chemotherapy and modified immunosuppressive therapy are among the most effective treatments for PTLD patients with an otherwise poor prognosis. Maintaining a fine balance between management of the PTLD and preventing allograft rejection is critically important.>.

Antemortem inhibition of phosphoinositide 3-kinase causes changes in meat quality traits in broiler chickens

Phosphoinositide 3-kinase (PI3K) is an enzyme that mediates endocrinological responses, such as intracellular signaling of insulin and growth factors, and plays important roles in muscle homeostasis and growth. In this study, the effect of antemortem PI3K activity on meat quality traits was investigated using broiler chickens whose PI3K was inhibited pharmacologically. Breast and thigh muscles were harvested from broilers treated with the PI3K inhibitor wortmannin, and meat quality traits were evaluated by determination of color, water-holding capacity, and breaking strength. The pH and concentrations of glycogen and free amino acids were also investigated as determinants of the chemical properties of meat. The results indicated that antemortem PI3K inhibition by wortmannin modified breast muscle color with lower L∗ values (P < 0.05) and b∗ values (P < 0.05) and higher a∗ values (P < 0.05). Antemortem PI3K inhibition also increased the water-holding capacity of breast muscles (P < 0.05), although breaking strength was not much affected. In addition, antemortem PI3K inhibition increased the concentrations of free amino acids in breast muscles, especially arginine (P < 0.05) and glutamic acid (P < 0.05). Similar effects were observed in thigh muscles. Lower glycogen levels at sacrifice (P < 0.05) and the resultant higher pH during the postmortem period (P < 0.05) were associated with PI3K inhibition-induced changes in meat quality traits. The wortmannin-treated muscles shared certain features with dark, firm, and dry meat which is a common abnormal meat. These findings suggest that antemortem PI3K activity contributes to meat quality traits and is involved in the molecular mechanism of the production of meat quality abnormalities.

Outcomes of idiopathic pulmonary arterial hypertension in Japanese children: a retrospective cohort study

Recently, targeted therapy has been developed for idiopathic pulmonary arterial hypertension (IPAH). Studies evaluating the prognosis of IPAH have been conducted in adults. However, there is no nationwide survey of pediatric patients with IPAH regarding the long-term prognosis in Japan. Therefore, we investigated the clinical outcomes of Japanese pediatric patients with IPAH and risk factors for a poor prognosis. This multi-center, retrospective cohort study included pediatric patients with IPAH under the age of 15 years, who were gleaned from the nationwide network of Japanese Society of Pediatric Cardiology and Cardiac Surgery (JSPCCS). The questionnaire was sent to members of JSPCCS in 2015. Patients who were diagnosed with IPAH from 1994 to 2014 were included. The primary endpoint was death or lung transplantation. Ninety-five patients were finally enrolled. Both the mean age at diagnosis and the mean follow-up duration were 7 years. Ninety-five percent of patients had received targeted therapy for IPAH during follow-up. The overall 1, 3, 5, and 10-year event free rate, estimated using Kaplan-Meier survival estimate, was 96, 91, 83, and 74%, respectively. The prognosis was significantly poorer in patients with increased right ventricular systolic pressure (RVp), mean pulmonary artery pressure (mPAP) (≥ 52 mmHg), cardiothoracic ratio (≥ 55%), and levels of B-type natriuretic peptide (BNP) during follow-up (≥ 300 pg/mL) than in those without these parameters. In conclusion, in Japanese children with IPAH, the event-free rate for death or lung transplantation was found to be good. Greater RVp, mPAP, BNP levels during follow-up, and cardiothoracic ratio may be predictive indicators for a poor prognosis.

A catalog of associations between rare coding variants and COVID-19 outcomes

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes coronavirus disease-19 (COVID-19), a respiratory illness that can result in hospitalization or death. We investigated associations between rare genetic variants and seven COVID-19 outcomes in 543,213 individuals, including 8,248 with COVID-19. After accounting for multiple testing, we did not identify any clear associations with rare variants either exome-wide or when specifically focusing on (i) 14 interferon pathway genes in which rare deleterious variants have been reported in severe COVID-19 patients; (ii) 167 genes located in COVID-19 GWAS risk loci; or (iii) 32 additional genes of immunologic relevance and/or therapeutic potential. Our analyses indicate there are no significant associations with rare protein-coding variants with detectable effect sizes at our current sample sizes. Analyses will be updated as additional data become available, with results publicly browsable at https://rgc-covid19.regeneron.com.

[The inhibitors of the apical sodium-dependent bile acid transporter (ASBT) as promising drugs]

Inhibition of the apical sodium-dependent bile acid transporter (ASBT, also known as IBAT - ileal bile acid transporter, SLC10A2) leads to disruption of the enterohepatic circulation of bile acids and their excretion with fecal masses. This is accompanied by cholesterol utilization for synthesis of new bile acids. ASBT inhibitors are promising drugs for the treatment of such diseases as non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, type 2 diabetes mellitus, necrotic enterocolitis, chronic constipation, atherosclerosis. To date the most known chemically synthesized inhibitors are: A3309, SHP626, A4250, 264W94, GSK2330672, SC-435. All of them are at different stages of clinical trials, which confirm the high efficacy and good tolerance of these inhibitors. Current trends in this field also include directed chemical synthesis of ASBT inhibitors, as well as their search among substances of plant origin.

Noonan syndrome-associated biallelic LZTR1 mutations cause cardiac hypertrophy and vascular malformations in zebrafish

Background

Variants in the LZTR1 (leucine‐zipper‐like transcription regulator 1) gene (OMIM #600574) have been reported in recessive Noonan syndrome patients. In vivo evidence from animal models to support its causative role is lacking.

Methods

By CRISPR‐Cas9 genome editing, we generated lztr1‐mutated zebrafish (Danio rerio). Analyses of histopathology and downstream signaling were performed to investigate the pathogenesis of cardiac and extracardiac abnormalities in Noonan syndrome.

Results

A frameshift deletion allele was created in the zebrafish lztr1. Crosses of heterozygotes obtained homozygous lztr1 null mutants that modeled LZTR1 loss‐of‐function. Histological analyses of the model revealed ventricular hypertrophy, the deleterious signature of Noonan syndrome‐associated cardiomyopathy. Further, assessment for extracardiac abnormalities documented multiple vascular malformations, resembling human vascular pathology caused by RAS/MAPK activation. Due to spatiotemporal regulation of LZTR1, its downstream function was not fully elucidated from western blots of adult tissue.

Conclusion

Our novel zebrafish model phenocopied human recessive Noonan syndrome and supported the loss‐of‐function mechanism of disease‐causing LZTR1 variants. The discovery of vascular malformations in mutants calls for the clinical follow‐up of patients to monitor for its emergence. The model will serve as a novel platform for investigating the pathophysiology linking RAS/MAPK signaling to cardiac and vascular pathology.

TEMPORAL CHANGES IN RADIOCESIUM DEPOSITION ON THE FUKUSHIMA FLOODPLAIN

There has been significant concern about increases in the exposure dose in living areas due to the accumulation of radiocesium discharged from contaminated mountainous forests in Fukushima. In this study, we investigated the history of radiocesium deposition on several floodplains in Fukushima following the nuclear power plant accident. Radiocesium concentrations in river suspended particles and the air dose rates on the floodplains were observed continuously. The annual sediment accumulation on the floodplains was 5.5-200 kg m-2, and the observed radiocesium concentration decreased with the decrease in the radiocesium concentration of suspended particles. The air dose rates on the floodplains were gradually decreasing with time. In 2015, with heavy flood discharge, a sediment accumulation of 180-200 kg m-2 and a sharp decrease in the air dose rate were observed at the Takase River, which does not have a reservoir. Conversely, the sediment accumulation at the Ukedo River was significantly reduced due to deposition in an upstream reservoir.

Silibinin efficacy in a rat model of pulmonary arterial hypertension using monocrotaline and chronic hypoxia

Background

C-X-C chemokine receptor type 4 (CXCR4) may be involved in the development of pulmonary arterial hypertension (PAH). CXCR4 inhibitor AMD3100 was described to have a positive effect on the prevention of pulmonary arterial muscularization in PAH models. Silibinin is a traditional medicine that has an antagonistic effect on CXCR4. We investigated the effect of silibinin using rat models of PAH.

Methods

PAH was induced by a single subcutaneous injection of monocrotaline. The rats were maintained in a chronic hypoxic condition (10% O₂) with or without silibinin. To evaluate the efficacy of silibinin on PAH, right ventricular systolic pressure (RVSP), Fulton index (weight ratio of right ventricle to the left ventricle and septum), percent medial wall thickness (% MT), and vascular occlusion score (VOS) were measured and calculated. Immunohistochemical analysis was performed targeting CXCR4 and c-Kit. Reverse transcription-quantitative polymerase chain reaction was performed for the stem cell markers CXCR4, stromal cell derived factor-1 (SDF-1), c-Kit, and stem cell factor (SCF), and the inflammatory markers monocyte chemoattractant protein 1 (MCP1), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFα). Statistical analyses were performed using t-test and one-way analysis of variance with Bonferroni’s post hoc test.

Results

Silibinin treatment for 1 week reduced RVSP and Fulton index. Treatment for 2 weeks reduced RVSP, Fulton index, % MT, and VOS, as well as downregulating the expression of CXCR4, SDF-1, and TNFα in pulmonary arteries. In contrast, treatment for 3 weeks failed to ameliorate PAH. The time-course study demonstrated that RVSP, Fulton index, % MT, and VOS gradually increased over time, with a decrease in the expression of CXCR4 and TNFα occurring after 2 weeks of PAH development. After 3 weeks, SDF-1, c-Kit, and SCF began to decrease and, after 5 weeks, MCP1 and IL-6 gradually accumulated.

Conclusions

The CXCR4 inhibitor silibinin can ameliorate PAH, possibly through the suppression of the CXCR4/SDF-1 axis, until the point where PAH becomes a severe and irreversible condition. Silibinin results in reduced pulmonary arterial pressure and delays pulmonary arteriolar occlusion and pulmonary vascular remodeling.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1041-y) contains supplementary material, which is available to authorized users.

Polysplenia Syndrome as a Risk Factor for Early Progression of Pulmonary Hypertension

BACKGROUND

Recent progress in surgical and intensive care has improved the prognosis of congenital heart disease (CHD) associated with heterotaxy syndrome. Less is known, however, about pulmonary vascular complications in these patients. Methods and Results: We reviewed medical records of 236 patients who were diagnosed with polysplenia syndrome at 2 institutions for pediatric cardiology in Japan from 1978 to 2015. We selected and compared the clinical records of 16 patients with polysplenia who had incomplete atrioventricular septal defect (AVSD) as the polysplenia group, and 22 age-matched patients with incomplete AVSD without any syndromes including polysplenia as the control group. Although the severity of systemic to pulmonary shunt was not significantly different between the groups, mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance index (PVRI) were significantly higher in the polysplenia group than the control (mPAP, 37.3 vs. 19.1 mmHg, P=0.001; PVRI, 5.7 vs. 1.4 WU∙m², P=0.014) before surgical intervention. On regression analysis, polysplenia influenced the development of pulmonary hypertension (PH) regardless of age at evaluation or degree of systemic to pulmonary shunt in the patients with incomplete AVSD.

CONCLUSIONS

Polysplenia syndrome is an independent risk factor for CHD-associated PH. Earlier intervention may be required to adjust the pulmonary blood flow in polysplenia syndrome with CHD to avoid the progression of PH.

Role of BRCA1-associated protein (BRAP) variant in childhood pulmonary arterial hypertension

Although mutations in several genes have been reported in pulmonary arterial hypertension (PAH), most of PAH cases do not carry these mutations. This study aimed to identify a novel cause of PAH. To determine the disease-causing variants, direct sequencing and multiplex ligation-dependent probe amplification were performed to analyze 18 families with multiple affected family members with PAH. In one of the 18 families with PAH, no disease-causing variants were found in any of BMPR2, ACVRL1, ENG, SMAD1/4/8, BMPR1B, NOTCH3, CAV1, or KCNK3. In this family, a female proband and her paternal aunt developed PAH in their childhood. Whole-exome next-generation sequencing was performed in the 2 PAH patients and the proband’s healthy mother, and a BRCA1-associated protein (BRAP) gene variant, p.Arg554Leu, was identified in the 2 family members with PAH, but not in the proband’s mother without PAH. Functional analyses were performed using human pulmonary arterial smooth muscle cells (hPASMCs). Knockdown of BRAP via small interfering RNA in hPASMCs induced p53 signaling pathway activation and decreased cell proliferation. Overexpression of either wild-type BRAP or p.Arg554Leu-BRAP cDNA constructs caused cell death confounding these studies, however we observed higher levels of p53 signaling inactivation and hPASMC proliferation in cells expressing p.Arg554Leu-BRAP compared to wild-type BRAP. In addition, p.Arg554Leu-BRAP induced decreased apoptosis of hPASMCs compared with wild-type BRAP. In conclusion, we have identified a novel variant of BRAP in a Japanese family with PAH and our results suggest it could have a gain-of-function. This study sheds light on new mechanism of PAH pathogenesis.

Bioelectrical impedance analysis in the management of heart failure in adult patients with congenital heart disease

OBJECTIVE

The recognition of fluid retention is critical in treating heart failure (HF). Bioelectrical impedance analysis (BIA) is a well-known noninvasive method; however, data on its role in managing patients with congenital heart disease (CHD) are limited. Here, we aimed to clarify the correlation between BIA and HF severity as well as the prognostic value of BIA in adult patients with CHD.

DESIGN

This prospective single-center study included 170 patients with CHD admitted between 2013 and 2015. We evaluated BIA parameters (intra- and extracellular water, protein, and mineral levels, edema index [EI, extracellular water-to-total body water ratio]), laboratory values, and HF-related admission prevalence.

RESULTS

Patients with New York Heart Association (NYHA) functional classes III-IV had a higher EI than those with NYHA classes I-II (mean ± SD, 0.398 ± 0.011 vs 0.384 ± 0.017, P < .001). EI was significantly correlated with brain natriuretic peptide level (r = 0.51, P < .001). During the mean follow-up period of 7.1 months, Kaplan-Meier analysis showed that a discharge EI > 0.386, the median value in the present study, was significantly associated with a future increased risk of HF-related admission (HR = 4.15, 95% CI = 1.70－11.58, P < .001). A body weight reduction during hospitalization was also related to EI reduction.

CONCLUSIONS

EI determined using BIA could be a useful marker for HF severity that could predict future HF-related admissions in adult patients with CHD.

High expression of CXCR4 and stem cell markers in a monocrotaline and chronic hypoxia-induced rat model of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe and fatal clinical syndrome. C-X-C chemokine receptor type 4 (CXCR4) is known to serve a key role in recruiting mesenchymal stem cells (MSCs) from the bone marrow. In the present study, a rat model of PAH induced by 5 weeks of chronic hypoxia and treatment with a single injection of monocrotaline (60 mg/kg) was used to investigate the involvement of CXCR4 in PAH. Successful establishment of the PAH model was confirmed by significant differences between the PAH and control groups in right ventricular systolic pressure, Fulton index, wall thickness, vascular occlusion score determined by immunohistochemical staining and the expression of inflammatory markers measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression of CXCR4 and other stem cell markers were compared in the PAH and control groups. RT-qPCR showed that the expression of CXCR4, SCF, c-Kit, and CD29, which are expressed in MSCs, was significantly higher in the PAH group. Immunohistochemical staining also showed that the numbers of CXCR4-, c-Kit- and CD90-positive cells were significantly higher in the PAH group. These results suggest that CXCR4 is involved in the pathogenesis of PAH and that stem cells may serve an important role in pulmonary vascular remodeling.