The Diaphragmatic Initiated Ventilatory Assist (DIVA) trial: study protocol for a randomized controlled trial comparing rates of extubation failure in extremely premature infants undergoing extubation to non-invasive neurally adjusted ventilatory assist versus non-synchronized nasal intermittent positive pressure ventilation.

BACKGROUND: Invasive mechanical ventilation contributes to bronchopulmonary dysplasia (BPD), the most common complication of prematurity and the leading respiratory cause of childhood morbidity. Non-invasive ventilation (NIV) may limit invasive ventilation exposure and can be either synchronized or non-synchronized (NS). Pooled data suggest synchronized forms may be superior. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) delivers NIV synchronized to the neural signal for breathing, which is detected with a specialized catheter. The DIVA (Diaphragmatic Initiated Ventilatory Assist) trial aims to determine in infants born 240/7-276/7 weeks' gestation undergoing extubation whether NIV-NAVA compared to non-synchronized nasal intermittent positive pressure ventilation (NS-NIPPV) reduces the incidence of extubation failure within 5 days of extubation. METHODS: This is a prospective, unblinded, pragmatic, multicenter phase III randomized clinical trial. Inclusion criteria are preterm infants 24-276/7 weeks gestational age who were intubated within the first 7 days of life for at least 12 h and are undergoing extubation in the first 28 postnatal days. All sites will enter an initial run-in phase, where all infants are allocated to NIV-NAVA, and an independent technical committee assesses site performance. Subsequently, all enrolled infants are randomized to NIV-NAVA or NS-NIPPV at extubation. The primary outcome is extubation failure within 5 days of extubation, defined as any of the following: (1) rise in FiO2 at least 20% from pre-extubation for > 2 h, (2) pH ≤ 7.20 or pCO2 ≥ 70 mmHg; (3) > 1 apnea requiring positive pressure ventilation (PPV) or ≥ 6 apneas requiring stimulation within 6 h; (4) emergent intubation for cardiovascular instability or surgery. Our sample size of 478 provides 90% power to detect a 15% absolute reduction in the primary outcome. Enrolled infants will be followed for safety and secondary outcomes through 36 weeks' postmenstrual age, discharge, death, or transfer. DISCUSSION: The DIVA trial is the first large multicenter trial designed to assess the impact of NIV-NAVA on relevant clinical outcomes for preterm infants. The DIVA trial design incorporates input from clinical NAVA experts and includes innovative features, such as a run-in phase, to ensure consistent technical performance across sites. TRIAL REGISTRATION: www. CLINICALTRIALS: gov , trial identifier NCT05446272 , registered July 6, 2022.

Perspectives: on Precision Nutrition Research in Heart, Lung, and Blood Diseases and Sleep Disorders.

The release of the 2020-2030 Strategic Plan for NIH Nutrition Research (SPNR) and its emphasis on precision nutrition has provided an opportunity to identify future nutrition research that addresses individual variability in response to diet and nutrition across the life span-including those relevant to the Strategic Vision of the National Heart, Lung, and Blood Institute (NHLBI). The SPNR and the NHLBI's Strategic Vision were developed with extensive input from the extramural research community, and both have 4 overarching strategic goals within which are embedded several objectives for research. For the SPNR, these include 1) spur discovery science and normal biological functions (e.g., role of the microbiome in health and disease), 2) population science to understand individual differences (e.g., biomarkers including 'omics that predict disease status), 3) emerging scientific areas of investigation and their application (e.g., data science, artificial intelligence), and 4) cross-cutting themes (e.g., training the scientific workforce and minority health and health disparities). These strategic goals and objectives serve as blueprints for research and training. Nutrition remains important in the prevention and treatment of heart, lung, blood, and sleep (HLBS) disorders and diseases, and the NHLBI has played a pivotal role in supporting nutrition research. In this paper, we report important gaps in the scientific literature related to precision nutrition in HLBS diseases. Research opportunities that could stimulate precision nutrition and their alignment with the SPNR and the NHLBI Strategic Vision Objectives are provided. These opportunities include 1) exploring individual differences in response to varying dietary patterns and nutrients; 2) investigating genetic/epigenetic, biological (e.g., microbiome, biomarkers), social, psychosocial, and environmental underpinnings of individual variability in diet; 3) elucidating the role of circadian rhythm and chrononutrition; and 4) applying implementation science research methods in precision nutrition interventions relevant to HLBS diseases.

Pulmonary Complications of Pediatric Hematopoietic Cell Transplantation. A National Institutes of Health Workshop Summary.

Approximately 2,500 pediatric hematopoietic cell transplants (HCTs), most of which are allogeneic, are performed annually in the United States for life-threatening malignant and nonmalignant conditions. Although HCT is undertaken with curative intent, post-HCT complications limit successful outcomes, with pulmonary dysfunction representing the leading cause of nonrelapse mortality. To better understand, predict, prevent, and/or treat pulmonary complications after HCT, a multidisciplinary group of 33 experts met in a 2-day National Institutes of Health Workshop to identify knowledge gaps and research strategies most likely to improve outcomes. This summary of Workshop deliberations outlines the consensus focus areas for future research.

Pre-Vent: the prematurity-related ventilatory control study.

BACKGROUND: The increasing incidence of bronchopulmonary dysplasia in premature babies may be due in part to immature ventilatory control, contributing to hypoxemia. The latter responds to ventilation and/or oxygen therapy, treatments associated with adverse sequelae. This is an overview of the Prematurity-Related Ventilatory Control Study which aims to analyze the under-utilized cardiorespiratory continuous waveform monitoring data to delineate mechanisms of immature ventilatory control in preterm infants and identify predictive markers. METHODS: Continuous ECG, heart rate, respiratory, and oxygen saturation data will be collected throughout the NICU stay in 500 infants < 29 wks gestation across 5 centers. Mild permissive hypercapnia, and hyperoxia and/or hypoxia assessments will be conducted in a subcohort of infants along with inpatient questionnaires, urine, serum, and DNA samples. RESULTS: Primary outcomes will be respiratory status at 40 wks and quantitative measures of immature breathing plotted on a standard curve for infants matched at 36-37 wks. Physiologic and/or biologic determinants will be collected to enhance the predictive model linking ventilatory control to outcomes. CONCLUSIONS: By incorporating bedside monitoring variables along with biomarkers that predict respiratory outcomes we aim to elucidate individualized cardiopulmonary phenotypes and mechanisms of ventilatory control contributing to adverse respiratory outcomes in premature infants.

The Renin-Angiotensin and Renal Dopaminergic Systems Interact in Normotensive Humans.

The renin-angiotensin-aldosterone (RAAS) and renal dopaminergic systems interact to maintain sodium balance. High NaCl intake increases renal synthesis of dopamine and dopaminergic receptor activity, decreasing epithelial sodium transport, whereas sodium deficit activates the RAAS, increasing epithelial sodium transport. We tested the hypothesis that attenuation of the natriuretic effect of dopamine D1-like receptors during salt restriction results in part from increased RAAS activity in seven salt-resistant normotensive adults using a double-blind placebo-controlled balanced crossover design. All subjects attained sodium balance on low (50 mmol Na(+)/day) and high (300 mmol Na(+)/day) NaCl diets, administered 4 weeks apart. Sodium, potassium, lithium, para-aminohippurate, and creatinine clearances were measured before, during, and after a 3-hour infusion of fenoldopam, a D1-like receptor agonist, with and without pretreatment with enalapril, an angiotensin converting enzyme inhibitor. On the high NaCl diet, fenoldopam-induced natriuresis was associated with the inhibition of renal proximal and distal tubule sodium transport. On the low NaCl diet, fenoldopam decreased renal distal tubule sodium transport but did not cause natriuresis. The addition of enalapril to fenoldopam restored the natriuretic effect of fenoldopam and its inhibitory effect on proximal tubule sodium transport. Thus, on a high NaCl diet fenoldopam causes natriuresis by inhibiting renal proximal and distal tubule transport, but on a low NaCl diet the increased RAAS activity prevents the D1-like receptor from inhibiting renal proximal tubule sodium transport, neutralizing the natriuretic effect of fenoldopam. These results demonstrate an interaction between the renin-angiotensin and renal dopaminergic systems in humans and highlight the influence of dietary NaCl on these interactions.

Targeting of the enhanced green fluorescent protein reporter to adrenergic cells in mice.

Adrenaline and noradrenaline are important neurotransmitter hormones that mediate physiological stress responses in adult mammals, and are essential for cardiovascular function during a critical period of embryonic/fetal development. In this study, we describe a novel mouse model system for identifying and characterizing adrenergic cells. Specifically, we generated a reporter mouse strain in which a nuclear-localized enhanced green fluorescent protein gene (nEGFP) was inserted into exon 1 of the gene encoding Phenylethanolamine n-methyltransferase (Pnmt), the enzyme responsible for production of adrenaline from noradrenaline. Our analysis demonstrates that this knock-in mutation effectively marks adrenergic cells in embryonic and adult mice. We see expression of nEGFP in Pnmt-expressing cells of the adrenal medulla in adult animals. We also note that nEGFP expression recapitulates the restricted expression of Pnmt in the embryonic heart. Finally, we show that nEGFP and Pnmt expressions are each induced in parallel during the in vitro differentiation of pluripotent mouse embryonic stem cells into beating cardiomyocytes. Thus, this new mouse genetic model should be useful for the identification and functional characterization of adrenergic cells in vitro and in vivo.

The d5 dopamine receptor mediates large-conductance, calcium- and voltage-activated potassium channel activation in human coronary artery smooth muscle cells.

Large-conductance, calcium- and voltage-activated potassium (BK(Ca)) channels hyperpolarize coronary artery smooth muscle cells, causing vasorelaxation. Dopamine activates BK(Ca) channels by stimulating D(1)-like receptor-mediated increases in cAMP in porcine coronary artery myocytes. There are two D(1)-like receptors (R), D(1)R and D(5)R. We hypothesize that the specific D(1)-like receptor involved in BK(Ca) channel activation in human coronary artery smooth muscle cells (HCASMCs) is the D(5)R and that activation occurs via cAMP cross-activation of cGMP-dependent protein kinase (PKG), rather than cAMP-dependent protein kinase (PKA). The effects of D(1)-like receptor agonists and antagonists on BK(Ca) channel opening in HCASMCs were examined in the presence and absence of PKG/PKA inhibition by cell-attached patch clamp. In the absence of commercially available ligands specific for D(1)R or D(5)R, D(1)R or D(5)R protein was down-regulated by transfecting HCASMCs with human D(1)R or D(5)R antisense oligonucleotides, respectively: cells transfected with scrambled oligonucleotides and nontransfected HCASMCs served as controls. The predominant ion channel conducting outward currents in nontransfected HCASMCs was identified as the large-conductance, calcium- and voltage-activated potassium (BK(Ca)) channel, which was activated by D(1)-like receptor agonists despite PKA inhibition with (9R,10S,12S)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid (KT 5720) (300 nM), but was abolished by inhibiting PKG with 9-methoxy-9-methoxycarbonyl-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy-1H,8H,11H-2,7b-11a-triazadibenzo(a,g) cycloocta(cde)-trinden-1-one (KT 5823) (300 nM). D(1)-like receptor agonists activated BK(Ca) channels in all transfected cells except those transfected with D(5)R antisense oligonucleotides. Thus, the dopamine (D(1)-like) receptor mediates activation of BK(Ca) channels in HCASMCs by D(5)R, not D(1)R, and via PKG, not PKA. This is the first report of differential D(1)-like receptor regulation of vascular smooth muscle function in human cells.

Discordance in interpretation of chest radiographs between pediatric intensivists and a radiologist: impact on patient management.

PURPOSE: When radiologists are not available, chest radiographs (CXRs) of pediatric intensive care unit (PICU) patients are commonly interpreted by pediatric intensivists. We prospectively investigated the frequency of errors in CXR interpretation by pediatric intensivists and their impact on patient management. MATERIALS AND METHODS: Chest radiographs of PICU patients were evaluated by 5 pediatric intensivists then by a pediatric radiologist (the "gold standard"). If the interpretation of the radiologist and intensivist differed, an independent intensivist determined whether a management change took place. A pediatric pulmonologist determined how many intensivist interpretations were different from the radiologist's interpretations. RESULTS: Seven hundred twenty-eight radiographic findings were identified by the radiologist in 460 CXRs. There were 33 interpretation errors by the intensivists (4.5% of the findings in 7.1% of the CXRs). Only 3/33 error corrections (0.45% of the findings in 0.7% of the CXRs) resulted in change in patient management. CONCLUSIONS: Errors in interpretation of CXRs by pediatric intensivists were common but less than that in other series, probably because of education of the pediatric intensivists through daily rounds with the radiologist. Although interpretation errors that affected patient management were rare, their clinical importance supports the growing practice of 24/7 remote radiograph reading by radiologists.

Lipid rafts keep NADPH oxidase in the inactive state in human renal proximal tubule cells.

Recent studies have indicated the importance of cholesterol-rich membrane lipid rafts (LRs) in oxidative stress-induced signal transduction. Reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidases, the major sources of reactive oxygen species, are implicated in cardiovascular diseases, including hypertension. We tested the hypothesis that NADPH oxidase subunits and activity are regulated by LRs in human renal proximal tubule cells. We report that a high proportion of p22(phox) and the small GTPase Rac1 are expressed in LRs in human renal proximal tubule cells. The D(1)-like receptor agonist, fenoldopam (1 micromol/L per 20 minutes) dispersed Nox subunits within LRs and non-LRs and decreased oxidase activity (30.7+/-3.3%). In contrast, cholesterol depletion (2% methyl-beta-cyclodextrin [beta CD]) translocated NADPH oxidase subunits out of LRs and increased oxidase activity (154.0+/-10.5% versus control, 103.1+/-3.4%), which was reversed by cholesterol repletion (118.9+/-9.9%). Moreover, NADPH oxidase activation by beta CD (145.5+/-9.0%; control: 98.6+/-1.6%) was also abrogated by the NADPH oxidase inhibitors apocynin (100.4+/-3.2%) and diphenylene iodonium (9.5+/-3.3%). Furthermore, beta CD-induced reactive oxygen species production was reversed by knocking down either Nox2 (81.0+/-5.1% versus beta CD: 162.0+/-2.0%) or Nox4 (108.0+/-10.8% versus beta CD: 152.0+/-9.8%). We have demonstrated for the first time that disruption of LRs results in NADPH oxidase activation that is abolished by antioxidants and silencing of Nox2 or Nox4. Therefore, in human renal proximal tubule cells, LRs maintain NADPH oxidase in an inactive state.

Intrinsic cardiac catecholamines help maintain beating activity in neonatal rat cardiomyocyte cultures.

In the present study, we identify intrinsic cardiac adrenergic (ICA) cells in the neonatal rat heart using immunofluorescent histochemical staining techniques with antibodies that specifically recognize the major enzymes in the catecholamine biosynthetic pathway. ICA cells are most concentrated near the endocardial surface of ventricular myocardium, but are also found sporadically throughout the heart. In primary cultures of neonatal rat cardiomyocytes, ICA cells are closely associated with clusters of cardiomyocytes. To investigate a potential role for intrinsically produced catecholamines, we recorded beating rates in the presence and absence of the catecholamine-depleting agent reserpine or the adrenergic receptor blockers prazosin and timolol using videomicroscopy and photodiode sensors. Our results show that beating rates slow significantly when endogenous catecholamines are depleted or when their action is blocked with either a beta- or an alpha1-adrenergic receptor antagonist. These data indicate that intrinsic cardiac catecholamines help to maintain beating rates in neonatal rat cardiomyocyte cultures via stimulation of alpha1- and beta-adrenergic receptors. This information should help to increase our understanding of the physiologic mechanisms governing cardiovascular function in neonates.