Handling of human milk to prevent acquired cytomegalovirus infection in Japanese neonatal intensive care units: The first nationwide survey.

BACKGROUND: Human milk (HM) has been proven to provide immunological and nutritional advantages to neonates; however, acquired cytomegalovirus (CMV) infection can be associated with raw HM. In Japan, there are no standardized guidelines concerning HM handling. This cross-sectional survey was performed to reveal specific trends in HM handling in neonatal intensive care units (NICUs) in Japan. METHODS: A questionnaire was sent to 255 NICUs participating in the Japanese Neonatologist Association in May 2020. It involved HM handling practices, such as maternal screening, pasteurization, storage, and the workforce. RESULTS: Of 255 NICUs, 174 (67.8%) responded to the survey. Maternal CMV screening was carried out in 37 units (22.2%), and CMV inactivation in HM was performed in 44 units (26.5%). For CMV inactivation, a freeze-thawing method was employed in about 90% of units. In 70% of units providing CMV inactivation, CMV inactivation was conducted regardless of bodyweight and corrected gestational age of infants until the infants' discharge. Acquired CMV infection in preterm neonates was observed in 43 units (25.7%) in the survey period. CONCLUSION: A wide range of HM handling practices are used in Japanese NICUs. A national guideline for handling HM in NICUs should be created to promote the infection control of CMV.

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

BACKGROUND: Variants in the KCNQ1 gene, encoding the α-subunit of the slow component of delayed rectifier K+ channel Kv7.1, cause long QT syndrome (LQTS) type 1. The location of variants may be one of the factors in determining prognosis. However, detailed genotype-phenotype relationships associated with C-terminus variants remain unelucidated. OBJECTIVE: We investigated the clinical characteristics and variant-specific arrhythmic risks in patients with LQTS carrying Kv7.1 C-terminus variants. METHODS: The study comprises 202 consecutive patients with LQTS (98 probands and 104 family members) who carry a rare heterozygous variant in the Kv7.1 C-terminus. Their clinical characteristics and arrhythmic events were investigated. RESULTS: We identified 36 unique C-terminus variants (25 missense and 11 non-missense). The p.R366W variant was identified in 8 families, and p.T587M was identified in 21 families in large numbers from northwestern Japan. As for the location of the variant, we found that the variants in highly conserved regions and nonhelical domains were associated with longer QTc intervals compared with the variants in other regions. Both p.R366W and p.T587M variants are located in the highly conserved and functionally pivotal regions close to helices A and D, which are associated with calmodulin binding and channel assembly (tetramerization), respectively. The probands carrying p.T587M and p.R366W variants had worse arrhythmia outcomes compared with those with other C-terminus variants. The haplotype analysis of p.T587M families was suggestive of a founder effect. CONCLUSION: The arrhythmic risk of C-terminus variants in Kv7.1 in LQTS is not homogeneous, and locations of variants can be a determining factor for prognosis.

A severe case of cardiospondylocarpofacial syndrome with a novel MAP3K7 variant.

Cardiospondylocarpofacial syndrome (CSCFS) is a congenital malformation characterized by growth retardation, facial features, short toes with carpal and tarsal fusion, extensive posterior neck vertebral fusion, congenital heart disease, and deafness. Here, we report a severe case of CSCFS with a novel variant, p.Thr187Ile, in MAP3K7. Thr187 is the main phosphorylation site for TGF-beta-activated kinase 1 encoded by MAP3K7, and this variant may cause significant abnormalities in downstream signaling.

The serum thioredoxin-1 levels are not associated with bronchopulmonary dysplasia and retinopathy of prematurity.

BACKGROUND: We hypothesized that the serum TRX-1 in extremely preterm infants (EPIs) after birth was associated with the development of severe bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP). METHODS: This single-centered retrospective study enrolled EPIs treated at our institution. Serum TRX-1 concentrations of the residual samples taken on admission, day 10-20 of life, and 36-40 weeks of postmenstrual age (PMA) were measured with an enzyme-linked immunosorbent assay. RESULTS: The serum TRX-1 levels on admission were not different between the severe BPD (n = 46) and non-severe BPD groups (n = 67): [median (interquartile range) 147 (73.0-231) vs. 164 (80.5-248) ng/mL] (P = 0.57). These had no significant difference between the severe ROP (n = 47) and non-severe ROP groups (n = 66): [164 (71.3-237) vs. 150 (80.9-250) ng/mL] (P = 0.93). The TRX-1 levels at 10-20 days of life and 36-40 weeks of PMA also had no association with the development of severe BPD and ROP. CONCLUSION: The serum TRX-1 levels after birth are not predictive of severe BPD and ROP. IMPACT: Serum thioredoxin-1 levels in extremely preterm infants on the day of birth are lower than those in term or near-term infants hospitalized for transient tachypnea of the newborn. In extremely preterm infants, the serum thioredoxin-1 levels on the day of birth, at 10-20 days of life, and at postmenstrual age of 36-40 weeks were not associated with severe bronchopulmonary dysplasia and retinopathy of prematurity. The thioredoxin system is under development in extremely preterm infants; however, the serum thioredoxin-1 level is not predictive for severe bronchopulmonary dysplasia and retinopathy of prematurity.

Efficacy of cEEG and hepatic function to diagnose early acute encephalopathy.

BACKGROUND: Early treatment may improve the prognosis of acute encephalopathy (AE). However, methods for early diagnosis have not yet been established. In this paper, we examined methods for the early diagnosis of AE. METHODS: We extracted data on patients with febrile status epilepticus from the electronic medical records in our department between March 2016 and April 2021. Among these, 79 patients who underwent continuous electroencephalography (cEEG) were included in this study. Patients who exhibited psychomotor retardation or abnormal brain magnetic resonance imaging findings were assigned to Group E (n = 20), and the remaining patients were the control group (Group C, n = 59). The following tests were compared retrospectively between these two groups on admission: cEEG, serum hepatic function tests, and blood coagulation tests. RESULTS: The percentage of patients who exhibited high-amplitude slow waves or flat waves on cEEG at the time of admission was statistically significantly higher in Group E than in Group C (p < 0.01). Moreover, the percentage of patients whose high-amplitude slow waves or flat brain waves on admission disappeared within 6 h after an initial episode of convulsion was statistically significantly lower in Group E than in Group C (p < 0.01). Furthermore, all the items in the coagulation and the hepatic function tests were statistically significantly different in Group E from those in Group C (p < 0.05). CONCLUSION: These results showed that cEEG together with hepatic function and coagulation tests may be useful for the differential diagnosis of AE.

Therapeutic response of iNO in preterm infants with hypoxemic respiratory failure.

BACKGROUND: Inhaled nitric oxide (iNO) has been used as a rescue treatment for preterm infants with hypoxemic respiratory failure (HRF). However, its effectiveness remains debatable. Thus, in this study, we aimed to examine the impact of iNO therapy on HRF in extremely preterm infants. METHODS: A retrospective observational study was performed. Extremely preterm infants admitted to our neonatal intensive care unit who received iNO therapy later in their postnatal life were included. The oxygen saturation index (OSI) was used as an index of the severity of respiratory failure. RESULTS: In total, 30 extremely preterm infants were included in this study. Oxygenation was enhanced after the administration of iNO in infants with HRF. The OSI decreased by more than 20% in 12 patients (40%, positive responder) and did not decrease in 17 patients (57%, negative responder) within the first 6 h of treatment. The iNO initiation day was the significant independent factor associated with a positive response to iNO therapy in extremely preterm infants with HRF. CONCLUSIONS: iNO therapy was effective in enhancing oxygenation in extremely preterm infants with HRF. Earlier use of iNO was the significant factor associated with a positive therapeutic response to iNO, implying that iNO may be more effective in pulmonary vessels which are less damaged by shorter-term mechanical ventilation.

Beckwith-Wiedemann syndrome with long QT caused by a deletion involving KCNQ1 but not KCNQ1OT1:TSS-DMR.

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder with characteristic features, such as overgrowth, macroglossia, and exomphalos. Hypomethylation of the KCNQ1OT1:TSS-differentially methylated region (DMR) on the 11p15.5 imprinted region is the most common etiology of BWS. KCNQ1 on 11p15.5 is expressed from the maternally inherited allele in most tissues, but is biparentally expressed in the heart, and maternal KCNQ1 transcription is required to establish the maternal DNA imprint in the KCNQ1OT1:TSS-DMR. Loss of function variants in KCNQ1 result in long QT syndrome type 1 (LQT1). To date, eight patients with BWS due to KCNQ1 splice variants or structural abnormalities involving KCNQ1 but not the KCNQ1OT1:TSS-DMR have been reported (KCNQ1-BWS), and four of them had LQT1. We report a Japanese boy with BWS and LQT1 presenting with extreme hypomethylation of the KCNQ1OT1:TSS-DMR caused by a de novo 215-kb deletion including KCNQ1 but not the KCNQ1OT1:TSS-DMR on the maternal allele. He was born by emergency cesarean section due to suspicion of placental abruption at 30 weeks of gestation. His birth weight and length were +1.6 SD and +1.0 SD, respectively. His placental weight was +3.9 SD, and histological examination of his placenta was consistent with mesenchymal dysplasia. He had BWS clinical features, including macroglossia, ear creases and pits, body asymmetry, and rectus abdominis muscle dehiscence, and BWS was therefore diagnosed. LQT1 was first noticed at three months in a preoperative examination for lingual frenectomy. The summarized data of our patient and the previously reported eight patients in KCNQ1-BWS showed more frequent and earlier preterm births and smaller sized birth weight in KCNQ1-BWS cases than those with BWS caused by epimutation of the KCNQ1OT1:TSS-DMR. In addition, in five of nine patients with KCNQ1-BWS, LQT1 was detected, and two of them were identified at school age. In our patient and in another single case with LQT1, the LQT1 was not detected early despite neonatal ECG monitoring. For BWS patients with extreme hypomethylation of the KCNQ1OT1:TSS-DMR, searching for CNVs involving KCNQ1 and mutation screening for KCNQ1 should be considered together with periodic ECG monitoring. (338/500 words).

Efficacy of SubcutAneous implantable cardioVErter-defibrillators in ≤18 year-old CHILDREN: SAVE-CHILDREN registry.

BACKGROUND: In adult patients, subcutaneous implantable cardioverter defibrillators (S-ICDs) have been reported to be non-inferior to transvenous ICDs with respect to the incidence of device-related complications and inappropriate shocks. Only a few reports have investigated the efficacy of S-ICDs in the pediatric field. This study aimed to investigate the utility and safety of S-ICDs in patients ≤18 years old. METHODS: This study was a multicenter, observational, retrospective study on S-ICD implantations. Patients <18 years old who underwent S-ICD implantations were enrolled. The detailed data on the device implantations and eligibility tests, incidence of appropriate- and inappropriate shocks, and follow-up data were assessed. RESULTS: A total of 62 patients were enrolled from 30 centers. The patients ranged in age from 3 to 18 (median 14 years old [IQR 11.0-16.0 years]). During a median follow up of 27 months (13.3-35.8), a total of 16 patients (26.2%) received appropriate shocks and 13 (21.3%) received inappropriate shocks. The common causes of the inappropriate shocks were sinus tachycardia (n = 4, 30.8%) and T-wave oversensing (n = 4, 30.8%). In spite of the physical growth, the number of suitable sensing vectors did not change during the follow up. No one had any lead fractures or device infections in the chronic phase. CONCLUSIONS: Our study suggested that S-ICDs can prevent sudden cardiac death in the pediatric population with a low incidence of lead complications or device infections. The number of suitable sensing vectors did not change during the patients' growth.

Increased CaV1.2 late current by a CACNA1C p.R412M variant causes an atypical Timothy syndrome without syndactyly.

Timothy syndrome (TS) is a rare pleiotropic disorder associated with long QT syndrome, syndactyly, dysmorphic features, and neurological symptoms. Several variants in exon 8 or 8a of CACNA1C, a gene encoding the α-subunit of voltage-gated Ca2+ channels (Cav1.2), are known to cause classical TS. We identified a p.R412M (exon 9) variant in an atypical TS case. The aim of this study was to examine the functional effects of CACNA1C p.R412M on CaV1.2 in comparison with those of p.G406R. The index patient was a 2-month-old female infant who suffered from a cardio-pulmonary arrest in association with prolonged QT intervals. She showed dysmorphic facial features and developmental delay, but not syndactyly. Interestingly, she also presented recurrent seizures from 4 months. Genetic tests identified a novel heterozygous CACNA1C variant, p.R412M. Using heterologous expression system with HEK-293 cells, analyses with whole-cell patch-clamp technique revealed that p.R412M caused late Ca2+ currents by significantly delaying CaV1.2 channel inactivation, consistent with the underlying mechanisms of classical TS. A novel CACNA1C variant, p.R412M, was found to be associated with atypical TS through the same mechanism as p.G406R, the variant responsible for classical TS.

Thioredoxin-1 Ameliorates Oxygen-Induced Retinopathy in Newborn Mice through Modulation of Proinflammatory and Angiogenic Factors.

Oxygen-induced retinopathy (OIR) is an animal model for retinopathy of prematurity, which is a leading cause of blindness in children. Thioredoxin-1 (TRX) is a small redox protein that has cytoprotective and anti-inflammatory properties in response to oxidative stress. The purpose of this study was to determine the effect of TRX on OIR in newborn mice. From postnatal day 7, C57BL/6 wild type (WT) and TRX transgenic (TRX-Tg) mice were exposed to either 21% or 75% oxygen for 5 days. Avascular and neovascular regions of the retinas were investigated using fluorescence immunostaining. Fluorescein isothiocyanate-dextran and Hoechst staining were used to measure retinal vascular leakage. mRNA expression levels of proinflammatory and angiogenic factors were analyzed using quantitative polymerase chain reaction. Retinal histological changes were detected using immunohistochemistry. In room air, the WT mice developed well-organized retinas. In contrast, exposing WT newborn mice to hyperoxia hampered retinal development, increasing the retinal avascular and neovascular areas. After hyperoxia exposure, TRX-Tg mice had enhanced retinal avascularization compared with WT mice. TRX-Tg mice had lower retinal neovascularization and retinal permeability during recovery from hyperoxia compared with WT mice. In the early stages after hyperoxia exposure, VEGF-A and CXCL-2 expression levels decreased, while IL-6 expression levels increased in WT newborn mice. Conversely, no differences in gene expressions were observed in the TRX-Tg mouse retina. IGF-1 and Angpt1 levels did not decrease during recovery from hyperoxia in TRX-Tg newborn mice. As a result, overexpression of TRX improves OIR in newborn mice by modulating proinflammatory and angiogenic factors.

Association Between Deleterious SCN5A Variants and Ventricular Septal Defect in Young Patients With Brugada Syndrome.

OBJECTIVES: This study aimed to investigate the clinical characteristics of young patients with Brugada syndrome (BrS) with ventricular septal defect (VSD) and explore their genetic backgrounds. BACKGROUND: VSD is the most frequently occurring congenital heart disease among children. In contrast, BrS is a rare hereditary disease that is responsible for ventricular fibrillation and sudden cardiac death. Owing to their low incidence, the genetic background and clinical characteristics of patients with BrS with VSD have not been elucidated yet. METHODS: This study enrolled 36 individuals who were diagnosed with BrS when they were <20 years of age and performed genetic screening for SCN5A. The functional alteration in mutant Na+ channels was confirmed by patch clamp technique. RESULTS: Among the 36 patients with BrS, 5 had been diagnosed with VSD. This study found 14 heterozygous SCN5A variants in 15 unrelated patients. The 5 patients with VSD carried SCN5A variants, including R367S, R535∗, R893C, W1345C, and G1743R. The 3 missense variants (R893C, W1345C, and G1743R) have been proved to reduce peak Na+ current to <10%. A functional analysis of SCN5A R367S was performed and the variant was found to be nonfunctional. CONCLUSIONS: This study identified 5 loss-of-function SCN5A variants in 5 young patients with BrS with VSD. The study hypothesizes that altered blood flow in the right ventricular outflow tract leads to fibrosis and electrophysiological changes, predisposing the patients to earlier clinical presentation of BrS. In patients with VSD and ST-segment elevation in the right precordial leads, BrS should be considered and appropriate screening should be pursued accordingly.

School-based routine screenings of electrocardiograms for the diagnosis of long QT syndrome.

AIMS: School-based routine screenings of electrocardiograms (ECGs) have been performed upon admission to primary school (PS), junior high school (JHS), and high school (HS) in Japan. Though ECGs with prolonged QT intervals are occasionally found, the role of regular ECG screening tests in identifying long QT syndrome (LQTS) remains to be determined. We investigated the usefulness of the ECG screenings by comparing the results of genetic tests between students who showed QT-prolongation in the screenings and patients with LQTS. METHODS AND RESULTS: We genetically screened 341 students (106 PS, 173 JHS, and 62 HS). Of these, 230 subjects showed QT-prolongation during regular screenings (S-S group), and the other 111 patients were clinically consulted with suspected LQTS by paediatricians (C-C group). Genotype-phenotype relationships were compared between the two groups. The positive rates in the genetic tests were comparable among the two groups; however, symptomatic subjects were significantly fewer in the S-S group than the C-C group (3% vs. 70%). Compared to the genotype-negative subjects, the positive subjects showed significantly longer QTc (P < 0.0001) and more frequently presented LQTS risk scores with ≥3.5 points (P < 0.0001). Lethal arrhythmic events (LAE) occurred only in the C-C group; 18 subjects experienced LAE and 83% of them were found to carry variant(s) in the LQTS-related genes. CONCLUSION: The school-based ECG screenings are effective in identifying young patients with LQTS who require genetic analysis. If individuals are screened at a younger age, we can identify patients at risk earlier and provide preventative treatments.

Cytomegalovirus-related sepsis-like syndrome in very premature infants in Japan.

BACKGROUND: Very premature infants are at high risk of developing a symptomatic postnatal cytomegalovirus (CMV) disease, such as CMV-related sepsis-like syndrome (CMV-SLS). To address the limited data regarding its clinical features, a nationwide survey of CMV-SLS was conducted. METHODS: A questionnaire regarding CMV status and the clinical outcomes of CMV-SLS was sent to centers with reported cases of CMV-SLS. RESULTS: Twelve CMV-SLS cases, nine confirmed and three probable cases, were reported during the 3-year survey period. The median gestational age and birthweight were 25 weeks and 547 g, respectively. At disease onset, the median age was 49 days, and the corrected age was 31 weeks. Untreated breast milk was given in four cases (33%), whereas frozen breast milk was given in nine (75%). No specific symptoms and laboratory data regarding CMV-SLS were found. CONCLUSIONS: Very premature infants developed CMV-SLS after 1 month of age. There are no symptoms and signs specific for the diagnosis of CMV-SLS, so CMV-SLS should be considered as a differential diagnosis for premature infants who have unexplained sepsis-like symptoms during the convalescent phase.

Safety and feasibility of a factory-calibrated continuous glucose monitoring system in term and near-term infants at risk of hypoglycemia.

OBJECTIVE: Hypoglycemia increases the risk of adverse neurological outcomes in neonates. Adequate glucose monitoring requires repetitive and painful blood sampling. We aimed to evaluate the feasibility and accuracy of a continuous glucose monitoring system (CGMS) using factory-calibrated sensors to improve glucose monitoring and decrease the frequency of blood samples in neonates. MATERIAL AND METHODS: A methodological study was conducted to investigate a correlation of CGMS values with blood glucose measurements. RESULTS: Factory-calibrated CGMS sensors were placed on 21 infants at risk of hypoglycemia after delivery. CGMS values were compared with blood glucose concentrations. Thirty-seven pairs of CGMS and blood glucose values were obtained. There was a good correlation between CGMS and blood glucose values (R=0.67, p<0.01) with a mean difference (2 standard deviations) of 9.78 (-24.68 to 44.25) mg/dL. The mean differences at <3 hours and ≥3 hours after sensor placement were 17.35 (-4.54 to 39.21) mg/dL and 0.88 (-37.62 to 39.38) mg/dL, respectively. CGMS values were significantly higher than blood glucose concentration at <3 hours after sensor placement (p<0.01), whereas no significant differences in glucose values were observed between the CGMS and blood glucose values at ≥3 hours after sensor placement (p=0.852). CONCLUSION: The factory-calibrated CGMS was a safe and feasible modality for glucose monitoring. However, it has a tendency to overestimate the blood glucose concentrations. Therefore, this system should be used cautiously for neonates at risk of hypoglycemia, especially within 3 hours after sensor placement.

Novel electrocardiographic criteria for short QT syndrome in children and adolescents.

AIMS: Although shortening of the corrected QT interval (QTc) is a key finding in the diagnosis of short QT syndrome (SQTS), there may be overlap of the QTc between SQTS patients and normal subjects in childhood and adolescence. We aimed to investigate electrocardiographic findings for differentiation of SQTS patients. METHODS AND RESULTS: The SQTS group comprised 34 SQTS patients <20 years old, including 9 from our institutions and 25 from previous reports. The control group comprised 61 apparently healthy subjects with an QTc of <360 ms who were selected from 13 314 participants in a school-based screening programme. We compared electrocardiographic findings, including QT and Jpoint-Tpeak intervals (QT and J-Tpeak, respectively), those corrected by using the Bazett's and Fridericia's formulae (cB and cF, respectively) and early repolarization (ER) between the groups. QT, QTc by using Bazett's formula (QTcB), QTc by using Fridericia's formula (QTcF), J-Tpeak, J-Tpeak cB, and J-Tpeak cF were significantly shorter in the SQTS group than in the control group. On receiver operating characteristic curve analysis, the area under the curve (AUC) was largest for QTcB (0.888) among QT, QTcB, and QTcF, with a cut-off value of 316 ms (sensitivity: 79.4% and specificity: 96.7%). The AUC was largest for J-Tpeak cB (0.848) among J-Tpeak, J-Tpeak cB, and J-Tpeak cF, with a cut-off value of 181 ms (sensitivity: 80.8% and specificity: 91.8%). Early repolarization was found more frequently in the SQTS group than in the control group (67% vs. 23%, P = 0.001). CONCLUSION: A QTcB <316 ms, J-Tpeak cB < 181 ms, and the presence of ER may indicate SQTS patients in childhood and adolescence.

Impact of being large-for-gestational-age on neonatal mortality and morbidities in extremely premature infants.

BACKGROUND: Small for gestational age (SGA) infants have an increased risk for neonatal mortality and morbidities. However, few studies have examined the risk of large for gestational age (LGA) on these factors. We compared the risk of mortality and morbidities in LGA premature infants with those of appropriate for gestational age (AGA) infants. METHODS: Premature infants who were born between 2003 and 2012 at <26 weeks of gestational age were included. Relative risks of mortality and morbidities were evaluated between LGA and AGA infants. RESULTS: From 6898 extremely premature infants, 357 (5.2%), 5530 (80.2%), and 1011 (14.7%) were LGA, AGA, and SGA, respectively. A total of 5887 infants (5530 AGA and 357 LGA) were examined after excluding infants with congenital anomalies, unknown sex, and deficient data. The risk of mortality in LGA and AGA infants did not differ (relative risk (95% confidence interval) 1.04 (0.83-1.32)). Compared to AGA infants, LGA infants did not increase the risk of morbidities, including intraventricular hemorrhage, cystic periventricular leukomalacia, treated retinopathy of prematurity, necrotizing enterocolitis, and bronchopulmonary dysplasia. CONCLUSIONS: This study demonstrates that being born LGA does not correlate with an increased risk of mortality and morbidities in extremely premature infants. IMPACT: It is currently unknown if being large for gestational age is a risk for neonatal morbidity. A total of 6898 preterm infants born <26 weeks gestational age were included in the study. It was found that being large for gestational age was not related to increased risk of mortality and morbidities.

Difference in pyruvic acid metabolism between neonatal and adult mouse lungs exposed to hyperoxia.

OBJECTIVE: Neonatal lungs are more tolerant to hyperoxic injury than are adult lungs. This study investigated differences in the response to hyperoxic exposure between neonatal and adult mouse lungs using metabolomics analysis with capillary electrophoresis time-of-flight mass spectrometry (CE- TOFMS). METHODS: Neonatal and adult mice were exposed to 21% or 95% O2 for four days. Subsequently, lung tissue samples were collected and analyzed by CE-TOFMS. Pyruvate dehydrogenase (PDH) enzyme activity was determined using a microplate assay kit. PDH kinase (Pdk) 1, Pdk2, Pdk3, and Pdk4 mRNA expression levels were determined using quantitative reverse transcription-polymerase chain reaction. Pdk4 protein expression was quantified by Western blotting and Pdk4 protein localization was evaluated by immunohistochemistry. RESULTS: Levels of 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvic acid, and lactic acid were significantly elevated in the lungs of hyperoxia-exposed versus normoxia-exposed adult mice, whereas no significant differences were observed with hyperoxia exposure in neonatal mice. PDH activity was reduced in the lungs of adult mice only. Pdk4 mRNA expression levels after hyperoxic exposure were significantly elevated in adult mice compared with that in neonatal mice. Conversely, gene expression levels of Pdk1, Pdk2, and Pdk3 did not differ after hyperoxic exposure in either neonatal or adult mice. Pdk4 protein levels were also significantly increased in adult mouse lungs exposed to hyperoxia and were localized mainly to the epithelium of terminal bronchiole. CONCLUSIONS: Specific metabolites associated with glycolysis and gluconeogenesis were altered after hyperoxia exposure in the lungs of adult mice, but not in neonates, which was likely a result of reduced PDH activity due to Pdk4 mRNA upregulation under hyperoxia.

An NGS-based genotyping in LQTS; minor genes are no longer minor.

Mutations in KCNQ1, KCNH2, and SCN5A are the major cause of long QT syndrome (LQTS). More than 90% of the genotyped patients have been reported to carry mutations in any of these three genes. Thanks to increasing popularity of next generation sequencer (NGS), novel CACNA1C mutations have been identified among LQTS patients without extra-cardiac phenotypes. We aimed to clarify the frequency of genotypes in LQTS patients in the era of NGS. The study comprised 160 congenital LQTS patients (71 males) registered from November 2015 to September 2018. Inclusion criteria was QTc > 460 ms and Schwartz score ≥ 3. We performed genetic analysis using target gene method by NGS and confirmed the mutations by Sanger method. The median age for genetic screening was 13 (0-68) years. Sixteen patients suffered cardiac arrest, 47 syncope, and 97 were asymptomatic. We identified genetic mutations in 111 (69.4%) patients including 6 CACNA1C (5.4% of the genotyped patients) with 4 asymptomatic patients. Five (3.1%) patients carried double mutations; three out of them with RYR2 and KCNQ1 or KCNH2. In conclusion, CACNA1C screening would be recommended even if the patient is asymptomatic to elucidate the genetic background of the LQTS patients.

Attenuation of Hyperoxic Lung Injury in Newborn Thioredoxin-1-Overexpressing Mice through the Suppression of Proinflammatory Cytokine mRNA Expression.

The role of thioredoxin-1 (TRX), a small redox-active protein with antioxidant effects, during hyperoxic lung injury in newborns remains undetermined. We investigated TRX impact on hyperoxic lung injury in newborn TRX transgenic (TRX-Tg) and wildtype (WT) mice exposed to 21% or 95% O2 for four days, after which some mice were allowed to recover in room air for up to 14 days. Lung morphology was assessed by hematoxylin/eosin and elastin staining, as well as immunostaining for macrophages. The gene expression levels of proinflammatory cytokines were evaluated using quantitative real-time polymerase chain reaction. During recovery from hyperoxia, TRX-Tg mice exhibited an improved mean linear intercept length and increased number of secondary septa in lungs compared with the WT mice. Neonatal hyperoxia enhanced the mRNA expression levels of proinflammatory cytokines in the lungs of both TRX-Tg and WT mice. However, interleukin-6, monocyte chemoattractant protein-1, and chemokine (C-X-C motif) ligand 2 mRNA expression levels were reduced in the lungs of TRX-Tg mice compared with the WT mice during recovery from hyperoxia. Furthermore, TRX-Tg mice exhibited reduced macrophage infiltration in lungs during recovery. These results suggest that in newborn mice TRX ameliorates hyperoxic lung injury during recovery likely through the suppression of proinflammatory cytokines.