Oxygenation saturation index in neonatal hypoxemic respiratory failure.

BACKGROUND: This study aimed to assess the validity of the oxygenation saturation index (OSI) and the ratio of oxygen saturation to the fraction of inspired oxygen (FIO2) (S/F ratio) with percutaneous oxygen saturation (OSISpO2 and the Sp/F ratio) and to evaluate the correlation between these values and the oxygen index (OI). It also determined their cut-off values for predicting OI in accordance with neonatal hypoxic respiratory failure severity. METHODS: We reviewed the data of 77 neonates (gestational age 31.7 ± 6.1 weeks; birthweight, 1768 ± 983 g) requiring invasive mechanical ventilation between 2013 and 2020, 1233 arterial blood gas samples in total. We calculated the OI, OSISpO2, OSI with arterial oxygen saturation (SaO2) (OSISaO2), Sp/F ratio, and the ratio of SaO2 to FIO2 (Sa/F ratio). RESULTS: The regression and Bland-Altman analysis showed good agreement between OSISpO2 or the Sp/F ratio and OSISaO2 or the Sa/F ratio. Although a significant positive correlation was found between OSISpO2 and OI, OSISpO2 was overestimated in SpO2 > 98% with a higher slope of the fitted regression line than that below 98% of SpO2. Furthermore, receiver-operating characteristic curve analysis using only SpO2 ≤ 98% samples showed that the optimal cut-off points of OSISpO2 and the Sp/F ratio for predicting OI were: OI 5, 3.0 and 332; OI 10, 5.3 and 231; OI 15, 7.7 and 108; OI 20, 11.0 and 149; and OI 25, 17.1 and 103, respectively. CONCLUSION: The cut-off OSISpO2 and Sp/F ratio values could allow continuous monitoring for oxygenation changes in neonates with the potential for wider clinical applications.

The prediction of estimated cerebral perfusion pressure with trans-systolic time in preterm and term infants.

It is important to monitor cerebral perfusion in infants because hypo- and hyperperfusion can contribute to neurological injury. This study aimed to clarify the relationship between trans-systolic time (TST) and critical closing pressure (CrCP) or estimated cerebral perfusion pressure (CPPe) in neonates. Moreover, we aimed to determine the TST values in preterm and term infants with stable cerebral perfusion to clarify normative reference data. This multicentre prospective study included infants with arterial lines admitted to the neonatal intensive care units between December 2021 and August 2023. TST, CrCP, and CPPe were calculated using middle cerebral artery waveforms recorded using transcranial Doppler ultrasonography when clinicians collected arterial blood samples. Three hundred and sixty samples were obtained from 112 infants with a gestational age of 32 (interquartile range, 27-37) weeks and a birth weight of 1481 (956-2355) g. TST was positively correlated with CPPe (r = 0.60, p < 0.001), but not with CrCP (r = 0.08, p = 0.10). The normative reference values of TST in preterm and term infants without samples of hyper- or hypocapnia and/or hyper- or hypotension, which may affect cerebral perfusion, were as follows: ≤ 29 weeks, 0.12 (0.11-0.14) s; 30-36 weeks, 0.14 (0.12-0.15) s; and ≥ 37 weeks, 0.16 (0.14-0.17) s, respectively.  Conclusion: TST in neonates significantly correlated with CPPe, but not with CrCP. TST may be a good predictor of cerebral perfusion and potentially have wider clinical applications. What is Known: • Trans-systolic time (TST) is used in evaluating the effects of increased intracranial pressure on cerebral haemodynamics. However, little is known about the efficacy of TST in predicting neonatal cerebral perfusion pressure. What is New: • This study added evidence that TST correlated with estimated cerebral perfusion pressure, but not with critical closing pressure. Additionally, we showed the normative reference values of the TST in preterm and term infants.

Effectiveness of cardiac palliative surgery for trisomy 18 patients with increased pulmonary blood flow.

Congenital heart disease (CHD) is common among patients with trisomy 18 (T18), but cardiac surgery has been rarely indicated for T18 patients due to their short life span. Although the therapeutic effects of aggressive interventions were recently demonstrated for T18 patients, the subjects and factors examined varied, resulting in inconsistent findings. Therefore, the effects of cardiac surgery for T18 remain unclear. We herein investigated the outcomes of cardiac palliative surgery for CHD with increased pulmonary blood flow in T18 patients. 27 patients were examined: 13 (48.1%) underwent cardiac palliative surgery and 14 (51.9%) did not. Median survival times in the no-surgery and surgery groups were 223.0 days (95% confidence interval [CI]: 46-361 days) and 723.0 days (95% CI: 360-1447 days), respectively. The number of patients with pulmonary hypertension significantly differed between the two groups (5 of 14 in the no-surgery group and 0 in the surgery group). Five of 14 patients in the no-surgery group and 10 of 13 in the surgery group were discharged to home care (odds ratio: 10.8 [95% CI: 1.07-110.0]). Therefore, cardiac palliative surgery may be used to treat CHD with increased pulmonary blood flow in T18 patients.

Myosin Va, a Novel Interaction Partner of STXBP1, Is Required to Transport Syntaxin1A to the Plasma Membrane.

Syntaxin-binding protein 1 (STXBP1, also known as Munc18-1) regulates exocytosis as a chaperone protein of Syntaxin1A. The haploinsufficiency of STXBP1 causes early infantile-onset developmental and epileptic encephalopathy, known as STXBP1 encephalopathy. Previously, we reported impaired cellular localization of Syntaxin1A in induced pluripotent stem cell-derived neurons from an STXBP1 encephalopathy patient harboring a nonsense mutation. However, the molecular mechanism of abnormal Syntaxin1A localization in the haploinsufficiency of STXBP1 remains unknown. This study aimed to identify the novel interacting partner of STXBP1 involved in transporting Syntaxin1A to the plasma membrane. Affinity purification coupled with mass spectrometry analysis identified a motor protein Myosin Va as a potential binding partner of STXBP1. Co-immunoprecipitation analysis of the synaptosomal fraction from the mouse and tag-fused recombinant proteins revealed that the STXBP1 short splice variant (STXBP1S) interacted with Myosin Va in addition to Syntaxin1A. These proteins colocalized at the tip of the growth cone and axons in primary cultured hippocampal neurons. Furthermore, RNAi-mediated gene silencing in Neuro2a cells showed that STXBP1 and Myosin Va were required for membrane trafficking of Syntaxin1A. In conclusion, this study proposes a potential role of STXBP1 in the trafficking of the presynaptic protein Syntaxin1A to the plasma membrane in conjunction with Myosin Va.

Impaired neuronal activity and differential gene expression in STXBP1 encephalopathy patient iPSC-derived GABAergic neurons.

Syntaxin-binding protein 1 (STXBP1; also called MUNC18-1), encoded by STXBP1, is an essential component of the molecular machinery that controls synaptic vesicle docking and fusion. De novo pathogenic variants of STXBP1 cause a complex set of neurological disturbances, namely STXBP1 encephalopathy (STXBP1-E) that includes epilepsy, neurodevelopmental disorders and neurodegeneration. Several animal studies have suggested the contribution of GABAergic dysfunction in STXBP1-E pathogenesis. However, the pathophysiological changes in GABAergic neurons of these patients are still poorly understood. Here, we exclusively generated GABAergic neurons from STXBP1-E patient-derived induced pluripotent stem cells (iPSCs) by transient expression of the transcription factors ASCL1 and DLX2. We also generated CRISPR/Cas9-edited isogenic iPSC-derived GABAergic (iPSC GABA) neurons as controls. We demonstrated that the reduction in STXBP1 protein levels in patient-derived iPSC GABA neurons was slight (approximately 20%) compared to the control neurons, despite a 50% reduction in STXBP1 mRNA levels. Using a microelectrode array-based assay, we found that patient-derived iPSC GABA neurons exhibited dysfunctional maturation with reduced numbers of spontaneous spikes and bursts. These findings reinforce the idea that GABAergic dysfunction is a crucial contributor to STXBP1-E pathogenesis. Moreover, gene expression analysis revealed specific dysregulation of genes previously implicated in epilepsy, neurodevelopment and neurodegeneration in patient-derived iPSC GABA neurons, namely KCNH1, KCNH5, CNN3, RASGRF1, SEMA3A, SIAH3 and INPP5F. Thus, our study provides new insights for understanding the biological processes underlying the widespread neuropathological features of STXBP1-E.

Novel Two MRT Cell Lines Established from Multiple Sites of a Synchronous MRT Patient.

BACKGROUND/AIM: Malignant rhabdoid tumor (MRT) is a rare, aggressive neoplasm found in young children, caused by inactivation of a single gene, SNF5 (INI1, SMARCB1). MRT cases with multifocal tumors at diagnosis are categorized as synchronous MRT, often with a germline mutation of SNF5. The aim of this study was to establish new models useful in clarifying the biological basis of synchronous MRT. MATERIALS AND METHODS: We established two novel MRT cell lines, designated as KP-MRT-KS and KP-MRT-KSa, derived from different lesions and at a different time from a synchronous multifocal 7-month-old female MRT patient. RESULTS: Both cells showed typical morphology of MRT, with a compound genomic mutation in exons 2 and 5 of the SNF5 gene. The exon 2 mutation was found in the germline. CONCLUSION: These cell lines could serve as powerful tools for unveiling the molecular mechanism of refractory synchronous MRT.

Application of induced pluripotent stem cells in epilepsy.

Epilepsy is among the most common neurological disorders, affecting approximately 50 million people worldwide. Importantly, epilepsy is genetically and etiologically heterogenous, but several epilepsy types exhibit similar clinical presentations. Epilepsy-associated genes are being identified. However, the molecular pathomechanisms remain largely unknown. Approximately one-third of epilepsy is refractory to multiple conventional anti-epileptic drugs (AEDs). Induced pluripotent stem cells (iPSCs) provide an excellent tool to study the pathomechanisms underlying epilepsy and to develop novel treatments. Indeed, disease-specific iPSCs have been established for several genetic epilepsies. In particular, the molecular mechanisms underlying certain developmental and epileptic encephalopathies, such as Dravet syndrome, have been revealed. Modeling epilepsy with iPSCs enables new drug development based on the elucidated pathomechanisms. This can also be used to evaluate conventional AEDs and drug repurposing. Furthermore, transplanting neuronal cells derived from iPSCs into the brain has great potential to treat refractory epilepsies. Recent advances in iPSC technology have enabled the generation of neuronal organoids, or "mini brains." These organoids demonstrate electrophysiological activities similar to those of the brain and have the potential for extensive epilepsy research opportunities. Thus, the application of iPSCs in epilepsy provides insight into novel treatments based on the molecular pathomechanisms of epilepsy. In this review, we comprehensively discuss the studies conducted on iPSCs established for genetic epilepsy or epilepsies without major structural dysmorphic features.

Successful treatment of idiopathic colitis related to XIAP deficiency with allo-HSCT using reduced-intensity conditioning.

Recently, it has been reported that Crohn's-like intractable colitis occurred in approximately 20% of the patients with XIAP deficiency, also known as X-linked lymphoproliferative disease type 2. Because treatment used for Crohn's disease is not always effective for Crohn's-like colitis related to XIAP deficiency, more effective treatment should be established. Although several studies reported allo-HSCT might be promising even for Crohn's-like colitis related to XIAP deficiency, the outcome of allo-HSCT using MAC for XIAP deficiency is extremely poor due to frequent TRM. In addition, there is little information about the outcome of allo-HSCT for intractable colitis related to XIAP deficiency. Herein, we describe a patient with intractable colitis related to XIAP deficiency who was successfully treated with allo-HSCT using a reduced-intensity conditioning regimen. Although allo-HSCT using the RIC regimen might be a curative therapeutic option for intractable colitis with XIAP deficiency, the prognostic factors that will determine the success of allo-HSCT require further clinical information of more patients.