Single generation epigenetic change in captivity and reinforcement in subsequent generations in a delta smelt (Hypomesus transpacificus) conservation hatchery

A refugial population of the endangered delta smelt (Hypomesus transpacificus) has been maintained at the Fish Conservation and Culture Laboratory (FCCL) at UC Davis since 2008. Despite intense genetic management, fitness differences between wild and cultured fish have been observed at the FCCL. To investigate the molecular underpinnings of hatchery domestication, we used whole-genome bisulfite sequencing to quantify epigenetic differences between wild and hatchery-origin delta smelt. Differentially methylated regions (DMRs) were identified from 104 individuals by comparing the methylation patterns in different generations of hatchery fish (G1, G2, G3) with their wild parents (G0). We discovered a total of 132 significant DMRs (p < .05) between G0 and G1, 132 significant DMRs between G0 and G2, and 201 significant DMRs between G0 and G3. Our results demonstrate substantial differences in methylation patterns emerged between the wild and hatchery-reared fish in the early generations in the hatchery, with a higher proportion of hypermethylated DMRs in hatchery-reared fish. The rearing environment was found to be a stronger predictor of individual clustering based on methylation patterns than family, sex or generation. Our study indicates a reinforcement of the epigenetic status with successive generations in the hatchery environment, as evidenced by an increase in methylation in hypermethylated DMRs and a decrease in methylation in hypomethylated DMRs over time. Lastly, our results demonstrated heterogeneity in inherited methylation pattern in families across generations. These insights highlight the long-term consequences of hatchery practices on the epigenetic landscape, potentially impacting wild fish populations.

Paediatric obesity and Crohn's disease: a descriptive review of disease phenotype and clinical course

Objectives

In an era of increasing paediatric obesity and inflammatory bowel disease (IBD), this study evaluates the disease phenotype and clinical course of Crohn's disease (CD) in paediatric patients who are obese or overweight.

Methods

This is a retrospective, single-center, descriptive observational study from January 2010 to May 2020. Participants were included if they were: aged 2 to 18 years at the time of diagnosis, had a confirmed diagnosis of CD, and met WHO criteria for overweight or obesity at the time of diagnosis or within one year before diagnosis.

Results

A total of 345 patient charts with CD were screened during the study period, with 16 patients meeting inclusion criteria. Median age of patients was 15.5 years (IQR = 13.6, 16.1). Of the 15 patients over 10 years of age, median anthropometrics at diagnosis included body mass index (BMI) of 27.2 (IQR = 24.9, 29.4) and BMI for age z-score of 1.82 (IQR = 1.58, 2.19). Presenting symptoms included abdominal pain (80.0%), diarrhea (66.7%), hematochezia (66.7%), and weight loss (26.7%). Five patients (33.3%) had obesity-related complications. Median time from symptom onset to diagnosis was 146 days (IQR = 31, 367), and median time from diagnosis to remission was 229 days (IQR = 101.8, 496.3).

Conclusions

Patients with elevated BMI and CD present with typical symptoms of IBD, although weight loss was a less common presenting symptom. Time to disease remission is delayed, and obesity-related complications are common. Primary care providers must have a high degree of clinical suspicion in patients to prevent delays to gastroenterology referral and to improve time to disease remission.

Impact of Targeted Neonatal Echocardiography on Patent Ductus Arteriosus Management in a Canadian Tertiary Care Neonatal Unit: A Retrospective Cohort Study

OBJECTIVE

Comprehensive assessment of hemodynamic significance of a patent ductus arteriosus (PDA) is a common indication to perform targeted neonatal echocardiography (TNE). Impact of implementation of such an assessment on PDA management decisions remains to be reported. The objective of this study is to compare PDA-related hemodynamic information and PDA treatment decisions before and after introduction of TNE service.

STUDY DESIGN

This was a retrospective cohort study at a tertiary level neonatal intensive care unit in Southwestern Ontario. We investigated two time periods: Epoch-1 (non-TNE 2013-2016) versus Epoch-2 (TNE 2018-2021). We included neonates < 32 weeks with PDA. Data on baseline clinical characteristics, PDA-related echocardiographic parameters, PDA treatment details, and relevant long-term outcomes were collected. Primary outcome was defined as PDA treatment rates and need for multiple courses. Secondary outcomes included availability of PDA hemodynamic data and neonatal mortality/morbidity (PDA-related) RESULTS:  A total of 275 neonates were included. A total of 162 were assessed by conventional echocardiography in Epoch-1, whereas 113 were assessed by TNE in Epoch-2. Baseline clinical characteristics were similar. Epoch-2 had more echocardiographic assessments per patient of 2.7 (±1.8) versus 1.9 (± 1.3), p < 0.001 in Epoch1. The mean postnatal age at first echocardiographic assessment was higher in Epoch-2 (12.7 days [ ± 14.6]) than in Epoch-1 (7.9 days [ ± 10.4]), p < 0.001. Comprehensive hemodynamic assessment of PDA-related echocardiographic parameters such as PDA size, shunt pattern, effect on systemic circulation, and pulmonary circulation were higher in Epoch-2. Overall, PDA treatment rates were comparable in the two time periods. The use of multiple courses of treatment was higher in Epoch-1 than in Epoch-2 (47.8 vs. 31.7%, p = 0.047). In Epoch-1, neonates received PDA treatment earlier than in Epoch-2.

CONCLUSION

With the implementation of the TNE service, increased echocardiographic evaluations per patient were completed with availability of more comprehensive hemodynamic information about PDA. PDA treatment rates were similar in the two epochs, but need for multiple courses were less in TNE era.

KEY POINTS

· TNE allows comprehensive hemodynamic assessment of PDA.. · Implementation of dedicated TNE service led to increased use of echocardiography to assess PDA.. · Standardized hemodynamic assessment of PDA may allow improved individualization of treatment need..

Home-based fecal calprotectin utilization in a general pediatric gastroenterology clinic

OBJECTIVE

Remote investigation and monitoring have gained importance in ambulatory practice. A home-based fecal calprotectin (FC) test has been developed where the sample is processed and analyzed at home through a smartphone application. We aimed to assess the use of standard ELISA (sFC) versus home-based (hFC) FC testing in a general pediatric gastroenterology clinic.

METHODS

Ambulatory pediatric patients with hFC or sFC performed between August 2019 and November 2020 were included. Data regarding demographics, clinical characteristics, medication use, investigations, and final diagnosis, categorized as inflammatory bowel disease (IBD), functional gastrointestinal (GI) disorders, organic non-IBD (ONI) GI disorders, non-GI disorders, and undetermined after 6 months of investigation, were recorded.

RESULTS

A total of 453 FC tests from 453 unique patients were included. Of those, 249 (55%) were hFC. FC levels (median) were higher in children with IBD compared to non-IBD diagnosis (sFC 795 vs. 57 μg/g, hFC 595 vs. 47 μg/g, p < 0.001), and in ONI compared to functional GI disorders (sFC 85 vs. 54 μg/g, p = 0.003, hFC 57 vs. 40 μg/g, p < 0.001). No significant difference was observed between different ONI GI disorders or subtypes of functional disorders. Age did not significantly influence levels.

CONCLUSIONS

Overall, hFC and sFC provide similar results in the general pediatric GI ambulatory setting. FC is a sensitive but not disease-specific marker to identify patients with IBD. Values appear to be higher in ONI GI disorders over functional disorders, although cut-off values have yet to be determined.

Vascular Inflammation and Smooth Muscle Contractility: The Role of Nox1-Derived Superoxide and LRRC8 Anion Channels

Vascular inflammation underlies the development of hypertension, and the mechanisms by which it increases blood pressure remain the topic of intense investigation. Proinflammatory factors including glucose, salt, vasoconstrictors, cytokines, wall stress, and growth factors enhance contractility and impair relaxation of vascular smooth muscle cells. These pathways share a dependence upon redox signaling, and excessive activation promotes oxidative stress that promotes vascular aging. Vascular smooth muscle cell phenotypic switching and migration into the intima contribute to atherosclerosis, while hypercontractility increases systemic vascular resistance and vasospasm that can trigger ischemia. Here, we review factors that drive the initiation and progression of this vasculopathy in vascular smooth muscle cells. Emphasis is placed on the contribution of reactive oxygen species generated by the Nox1 NADPH oxidase which produces extracellular superoxide (O2•-). The mechanisms of O2•- signaling remain poorly defined, but recent evidence demonstrates physical association of Nox1 with leucine-rich repeat containing 8 family volume-sensitive anion channels. These may provide a pathway for influx of O2•- to the cytoplasm, creating an oxidized cytoplasmic nanodomain where redox-based signals can affect both cytoskeletal structure and vasomotor function. Understanding the mechanistic links between inflammation, O2•- and vascular smooth muscle cell contractility may facilitate targeting of anti-inflammatory therapy in hypertension.

DIFFERENTIAL SIGNALING EFFECTS OF ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS IN HUMAN WHOLE BLOOD INDICATE DISTINCT REGULATION OF THE NRF2 PATHWAY

ABSTRACT

Escherichia coli and Staphylococcus aureus are two of the most common bacterial species responsible for sepsis. While it is observed that they have disparate clinical phenotypes, the signaling differences elicited by each bacteria that drive this variance remain unclear. Therefore, we used human whole blood exposed to heat-killed E. coli or S. aureus and measured the transcriptomic signatures. Relative to unstimulated control blood, heat-killed bacteria exposure led to significant dysregulation (upregulated and downregulated) of >5,000 genes for each experimental condition, with a slight increase in gene alterations by S. aureus. While there was significant overlap regarding proinflammatory pathways, Gene Ontology overrepresentation analysis of the most altered genes suggested biological processes like macrophage differentiation and ubiquinone biosynthesis were more unique to heat-killed S. aureus, compared with heat-killed E. coli exposure. Using Ingenuity Pathway Analysis, it was demonstrated that nuclear factor erythroid 2-related factor 2 signaling, a main transcription factor in antioxidant responses, was predominately upregulated in S. aureus exposed blood relative to E. coli. Furthermore, the use of pharmacologics that preferentially targeted the nuclear factor erythroid 2-related factor 2 pathway led to differential cytokine profiles depending on the type of bacterial exposure. These findings reveal significant inflammatory dysregulation between E. coli and S. aureus and provide insight into the targeting of unique pathways to curb bacteria-specific responses.

Pediatric sepsis inflammatory blood biomarkers that correlate with clinical variables and severity of illness scores

BACKGROUND

Sepsis is a dysregulated systemic inflammatory response triggered by infection, resulting in organ dysfunction. A major challenge in clinical pediatrics is to identify sepsis early and then quickly intervene to reduce morbidity and mortality. As blood biomarkers hold promise as early sepsis diagnostic tools, we aimed to measure a large number of blood inflammatory biomarkers from pediatric sepsis patients to determine their predictive ability, as well as their correlations with clinical variables and illness severity scores.

METHODS

Pediatric patients that met sepsis criteria were enrolled, and clinical data and blood samples were collected. Fifty-eight inflammatory plasma biomarker concentrations were determined using immunoassays. The data were analyzed with both conventional statistics and machine learning.

RESULTS

Twenty sepsis patients were enrolled (median age 13 years), with infectious pathogens identified in 75%. Vasopressors were administered to 85% of patients, while 55% received invasive ventilation and 20% were ventilated non-invasively. A total of 24 inflammatory biomarkers were significantly different between sepsis patients and age/sex-matched healthy controls. Nine biomarkers (IL-6, IL-8, MCP-1, M-CSF, IL-1RA, hyaluronan, HSP70, MMP3, and MMP10) yielded AUC parameters > 0.9 (95% CIs: 0.837-1.000; p < 0.001). Boruta feature reduction yielded 6 critical biomarkers with their relative importance: IL-8 (12.2%), MCP-1 (11.6%), HSP70 (11.6%), hyaluronan (11.5%), M-CSF (11.5%), and IL-6 (11.5%); combinations of 2 biomarkers yielded AUC values of 1.00 (95% CI: 1.00-1.00; p < 0.001). Specific biomarkers strongly correlated with illness severity scoring, as well as other clinical variables. IL-3 specifically distinguished bacterial versus viral infection (p < 0.005).

CONCLUSIONS

Specific inflammatory biomarkers were identified as markers of pediatric sepsis and strongly correlated to both clinical variables and sepsis severity.

Perceived potentially inappropriate treatment in the PICU: frequency, contributing factors and the distress it triggers

Background

Potentially inappropriate treatment in critically ill adults is associated with healthcare provider distress and burnout. Knowledge regarding perceived potentially inappropriate treatment amongst pediatric healthcare providers is limited.

Objectives

Determine the frequency and factors associated with potentially inappropriate treatment in critically ill children as perceived by providers, and describe the factors that providers report contribute to the distress they experience when providing treatment perceived as potentially inappropriate.

Methods

Prospective observational mixed-methods study in a single tertiary level PICU conducted between March 2 and September 14, 2018. Patients 0-17 years inclusive with: (1) ≥1 organ system dysfunction (2) moderate to severe mental and physical disabilities, or (3) baseline dependence on medical technology were enrolled if they remained admitted to the PICU for ≥48 h, and were not medically fit for transfer/discharge. The frequency of perceived potentially inappropriate treatment was stratified into three groups based on degree of consensus (1, 2 or 3 providers) regarding the appropriateness of ongoing active treatment per enrolled patient. Distress was self-reported using a 100-point scale.

Results

Of 374 patients admitted during the study, 133 satisfied the inclusion-exclusion criteria. Eighteen patients (unanimous - 3 patients, 2 providers - 7 patients; single provider - 8 patients) were perceived as receiving potentially inappropriate treatment; unanimous consensus was associated with 100% mortality on 3-month follow up post PICU discharge. Fifty-three percent of providers experienced distress secondary to providing treatment perceived as potentially inappropriate. Qualitative thematic analysis revealed five themes regarding factors associated with provider distress: (1) suffering including a sense of causing harm, (2) conflict, (3) quality of life, (4) resource utilization, and (5) uncertainty.

Conclusions

While treatment perceived as potentially inappropriate was infrequent, provider distress was commonly observed. By identifying specific factor(s) contributing to perceived potentially inappropriate treatment and any associated provider distress, organizations can design, implement and assess targeted interventions.

A novel multiplex biomarker panel for profiling human acute and chronic kidney disease

Acute and chronic kidney disease continues to confer significant morbidity and mortality in the clinical setting. Despite high prevalence of these conditions, few validated biomarkers exist to predict kidney dysfunction. In this study, we utilized a novel kidney multiplex panel to measure 21 proteins in plasma and urine to characterize the spectrum of biomarker profiles in kidney disease. Blood and urine samples were obtained from age-/sex-matched healthy control subjects (HC), critically-ill COVID-19 patients with acute kidney injury (AKI), and patients with chronic or end-stage kidney disease (CKD/ESKD). Biomarkers were measured with a kidney multiplex panel, and results analyzed with conventional statistics and machine learning. Correlations were examined between biomarkers and patient clinical and laboratory variables. Median AKI subject age was 65.5 (IQR 58.5-73.0) and median CKD/ESKD age was 65.0 (IQR 50.0-71.5). Of the CKD/ESKD patients, 76.1% were on hemodialysis, 14.3% of patients had kidney transplant, and 9.5% had CKD without kidney replacement therapy. In plasma, 19 proteins were significantly different in titer between the HC versus AKI versus CKD/ESKD groups, while NAG and RBP4 were unchanged. TIMP-1 (PPV 1.0, NPV 1.0), best distinguished AKI from HC, and TFF3 (PPV 0.99, NPV 0.89) best distinguished CKD/ESKD from HC. In urine, 18 proteins were significantly different between groups except Calbindin, Osteopontin and TIMP-1. Osteoactivin (PPV 0.95, NPV 0.95) best distinguished AKI from HC, and β2-microglobulin (PPV 0.96, NPV 0.78) best distinguished CKD/ESKD from HC. A variety of correlations were noted between patient variables and either plasma or urine biomarkers. Using a novel kidney multiplex biomarker panel, together with conventional statistics and machine learning, we identified unique biomarker profiles in the plasma and urine of patients with AKI and CKD/ESKD. We demonstrated correlations between biomarker profiles and patient clinical variables. Our exploratory study provides biomarker data for future hypothesis driven research on kidney disease.

Extracellular SOD modulates canonical TNFα signaling and α5β1 integrin transactivation in vascular smooth muscle cells

TNFα activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs). The extracellular superoxide anion (O2•-) produced is essential for the pro-inflammatory effects of the cytokine but the specific contributions of O2•- to signal transduction remain obscure. Extracellular superoxide dismutase (ecSOD, SOD3 gene) is a secreted protein that binds to cell surface heparin sulfate proteoglycans or to Fibulin-5 (Fib-5, FBLN5 gene), an extracellular matrix protein that also associates with elastin and integrins. ecSOD converts O2•- to hydrogen peroxide (H2O2) which prevents NO• inactivation, limits generation of hydroxyl radical (OH•), and creates high local concentrations of H2O2. We hypothesized that ecSOD modifies TNFα signaling in VSMCs. Knockdown of ecSOD (siSOD3) suppressed downstream TNFα signals including MAPK (JNK and ERK phosphorylation) and NF-κB activation (luciferase reporter and IκB phosphorylation), interleukin-6 (IL-6) secretion, iNOS and VCAM expression, and proliferation (Sulforhodamine B assay, PCNA western blot). These effects were associated with significant reductions in the expression of both Type1 and 2 TNFα receptors. Reduced Fib-5 expression (siFBLN5) similarly impaired NF-κB activation by TNFα, but potentiated FAK phosphorylation at Y925. siSOD3 also increased both resting and TNFα-induced phosphorylation of FAK and of glycogen synthase kinase-3β (GSK3β), a downstream target of integrin linked kinase (ILK). These effects were dependent upon α5β1 integrins and siSOD3 increased resting sulfenylation (oxidation) of both integrin subunits, while preventing TNFα-induced increases in sulfenylation. To determine how ecSOD modified TNFα-induced inflammation in intact blood vessels, mesenteric arteries from VSMC-specific ecSOD knockout (KO) mice were exposed to TNFα (10 ng/ml) in culture for 48 h. Relaxation to acetylcholine and sodium nitroprusside was impaired in WT but not ecSOD KO vessels. Thus, ecSOD association with Fib-5 supports pro-inflammatory TNFα signaling while tonically inhibiting α5β1 integrin activation.

Duchenne muscular dystrophy respiratory profiles from real world registry data

INTRODUCTION

Understanding real-world profiles from neuromuscular databases is helpful for optimizing clinical care and planning research studies. The Canadian Neuromuscular Disease Registry (CNDR) has respiratory data from a population of boys with Duchenne Muscular Dystrophy (DMD).

OBJECTIVES

To describe cross-sectional respiratory profiles from a national DMD real-world dataset. To explore the relationship between forced vital capacity percent predicted (FVC%) and disease severity parameters: scoliosis, ambulation and ventilation status.

METHODS

Descriptive statistics summarized the respiratory profiles. The CNDR registry enrolls and collects DMD clinic data from 36 Canadian centers.

RESULTS

There were 414 participants enrolled. The age ranged from 2 to 36 years old. Pulmonary function test data were available for 323 participants. The use of ventilatory support was seen in a significant proportion (19.5%) of subjects by age 14-16 years and was used by the majority (69.2%) by age 20-22 years. FVC% declined at a rate of 3.19% per year with every 1-year increase in age. FVC% declined annually by 2.47% in nonambulatory participants versus by 0.96% in ambulatory participants. FVC% did not significantly change over age with the presence of scoliosis or use of ventilatory technology.

CONCLUSIONS

The data from this large cohort are valuable for understanding real-world patterns of clinical care and disease progression. There is a significant association between the loss of ambulation and the rate of FVC% decline. Further longitudinal studies are needed to better understand the impact of disease parameters on pulmonary function decline and the need for ventilatory support.

Paediatricians' awareness of Canadian screen time guidelines, perception of screen time use, and counselling during the COVID-19 pandemic

Objectives

Paediatricians are essential in guiding families on screen time use as digital media becomes increasingly prevalent. While this has been highlighted through the COVID-19 pandemic there is no literature on paediatricians' awareness of Canadian screen time guidelines, or perception of these guidelines during this time. The aim of this study was to assess pediatricians' knowledge, attitudes, and comfort with the Canadian Paediatric Society's (CPS) screen time guidelines, specifically during the COVID-19 pandemic.

Methods

Our survey was developed by a paediatric resident and paediatric endocrinologist, reviewed by local experts, and sent electronically to members of the CPS Community and Developmental Paediatrics sections.

Results

All 53 respondents were aware of current CPS screen time guidelines, and the majority self-reported fair to excellent knowledge of guidelines for both age groups (<5 years and school-aged children/adolescents). Over 80% noticed increased screen use during the pandemic, and 98% were somewhat or very concerned about screen use and their patients' health and well-being. Pediatricians reported concerns about associations between increased screen time with worsening behaviour, mental health concerns, obesity, and sedentary lifestyle. The greatest barrier to reducing screen time was perceived insufficient motivation or support from caregivers/families.

Conclusions

Responding Canadian paediatricians are knowledgeable and comfortable with current screen time guidelines in Canada. Despite this, there is increasing concern with health outcomes associated with screen use. These results highlight paediatricians' important role in counselling patients and may encourage further local advocacy and public education around screen use and associated health risks in children.

Emergency department visits and hospital admissions for suicidal ideation, self-poisoning and self-harm among adolescents in Canada during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic had profound effects on the mental wellbeing of adolescents. We sought to evaluate pandemic-related changes in health care use for suicidal ideation, self-poisoning and self-harm.

METHODS

We obtained data from the Canadian Institute for Health Information on emergency department visits and hospital admissions from April 2015 to March 2022 among adolescents aged 10-18 years in Canada. We calculated the quarterly percentage of emergency department visits and hospital admissions for a composite outcome comprising suicidal ideation, self-poisoning and self-harm relative to all-cause emergency department visits and hospital admissions. We used interrupted time-series methods to compare changes in levels and trends of these outcomes between the prepandemic (Apr. 1, 2015-Mar. 1, 2020) and pandemic (Apr. 1, 2020-Mar. 31, 2022) periods.

RESULTS

The average quarterly percentage of emergency department visits for suicidal ideation, self-poisoning and self-harm relative to all-cause emergency department visits was 2.30% during the prepandemic period and 3.52% during the pandemic period. The level (0.08%, 95% confidence interval [CI] -0.79% to 0.95%) or trend (0.07% per quarter, 95% CI -0.14% to 0.28%) of this percentage did not change significantly between periods. The average quarterly percentage of hospital admissions for the composite outcome relative to all-cause admissions was 7.18% during the prepandemic period and 8.96% during the pandemic period. This percentage showed no significant change in level (-0.70%, 95% CI -1.90% to 0.50%), but did show a significantly increasing trend (0.36% per quarter; 95% 0.07% to 0.65%) during the pandemic versus prepandemic periods, specifically among females aged 10-14 years (0.76% per quarter, 95% CI 0.22% to 1.30%) and females aged 15-18 years (0.56% per quarter, 95% CI 0.31% to 0.81%).

INTERPRETATION

The quarterly change in the percentage of hospital admissions for suicidal ideation, self-poisoning and self-harm increased among adolescent females in Canada during the first 2 years of the COVID-19 pandemic. This underscores the need to promote public health policies that mitigate the impact of the pandemic on adolescent mental health.

Evaluation of hospital management of paediatric out-of-hospital cardiac arrest

INTRODUCTION

Pediatric out of hospital cardiac arrest (POHCA) is rare, with high mortality and neurological morbidity. Adherence to Pediatric Advanced Life Support guidelines standardizes in-hospital care and improves outcomes. We hypothesized that in-hospital care of POHCA patients was variable and deviations from guidelines were associated with higher mortality.

METHODS

POHCA patients in the London-Middlesex region between January 2012 and June 2020 were included. The care of children with ongoing arrest (intra-arrest) and post-arrest outcomes were reviewed using the Children's Hospital, London Health Sciences Centre (LHSC) patient database and the Adverse Event Management System.

RESULTS

50 POHCA patients arrived to hospital, with 15 (30%) patients admitted and 2 (4.0%) surviving to discharge, both with poor neurological outcomes and no improvement at 90 days. Deviations occurred at every event with intra-arrest care deviations occurring mostly in medication delivery and defibrillation (98%). Post-arrest deviations occurred mostly in temperature monitoring (60%). Data missingness was 15.9% in the intra-arrest and 1.7% in the post-arrest group.

DISCUSSION

Deviations commonly occurred in both in-hospital arrest and post-arrest care. The study was under-powered to identify associations between DEVs and outcomes. Future work includes addressing specific deviations in intra-arrest and post-arrest care of POHCA patients and standardizing electronic documentation.

LRRC8A anion channels modulate vascular reactivity via association with myosin phosphatase rho interacting protein

Leucine-rich repeat containing 8A (LRRC8A) volume regulated anion channels (VRACs) are activated by inflammatory and pro-contractile stimuli including tumor necrosis factor alpha (TNFα), angiotensin II and stretch. LRRC8A associates with NADPH oxidase 1 (Nox1) and supports extracellular superoxide production. We tested the hypothesis that VRACs modulate TNFα signaling and vasomotor function in mice lacking LRRC8A exclusively in vascular smooth muscle cells (VSMCs, Sm22α-Cre, Knockout). Knockout (KO) mesenteric vessels contracted normally but relaxation to acetylcholine (ACh) and sodium nitroprusside (SNP) was enhanced compared to wild type (WT). Forty-eight hours of ex vivo exposure to TNFα (10 ng/mL) enhanced contraction to norepinephrine (NE) and markedly impaired dilation to ACh and SNP in WT but not KO vessels. VRAC blockade (carbenoxolone, CBX, 100 μM, 20 min) enhanced dilation of control rings and restored impaired dilation following TNFα exposure. Myogenic tone was absent in KO rings. LRRC8A immunoprecipitation followed by mass spectroscopy identified 33 proteins that interacted with LRRC8A. Among them, the myosin phosphatase rho-interacting protein (MPRIP) links RhoA, MYPT1 and actin. LRRC8A-MPRIP co-localization was confirmed by confocal imaging of tagged proteins, Proximity Ligation Assays, and IP/western blots. siLRRC8A or CBX treatment decreased RhoA activity in VSMCs, and MYPT1 phosphorylation was reduced in KO mesenteries suggesting that reduced ROCK activity contributes to enhanced relaxation. MPRIP was a target of redox modification, becoming oxidized (sulfenylated) after TNFα exposure. Interaction of LRRC8A with MPRIP may allow redox regulation of the cytoskeleton by linking Nox1 activation to impaired vasodilation. This identifies VRACs as potential targets for treatment or prevention of vascular disease.

Purpose Built Catheters for Minimally Invasive Surfactant Therapy: Experience from a Canadian Tertiary Level Neonatal Intensive Care Unit

Background

Minimally invasive surfactant therapy (MIST), a method of surfactant delivery via a thin catheter during spontaneous breathing, is an increasingly popular alternative to intubation and surfactant administration. Recently, purpose-built catheters for MIST received regulatory approval in Canada and became available for use. However, procedural success and user experience with such catheters have not been described.

Methods

This retrospective cohort study included neonates who received MIST using purpose-built catheters between January 1, 2021, and March 31, 2022. Two types of purpose-built catheters were used in this period - SurfCath™ and BLEScath™. Procedural success, number of attempts, and adverse events in neonates receiving MIST via the two catheters were compared using chi-square or Fisher's tests. User experience was described using an ease-of-use scale.

Results

Thirty-seven neonates met eligibility criteria; 22 received MIST via SurfCath™, whereas 15 received MIST via BLEScath™. Success rates were 91% in SurfCath™ and 93% in BLEScath™ (P> 0.994). Failed attempts were lower in SurfCath™ (23%) in comparison to BLEScath™ (33%), but the difference was not statistically significant (P=0.708). Among operators, 90% found SurfCath™ very easy/relatively easy to use compared to 43% of users reflecting the same degree of use with BLEScath™ (P=.021). There was no difference in adverse events.

Conclusion

This is the first study in Canada to report MIST with purpose-built catheters. Overall, the success rate was equally high with both catheters. Users subjectively reported higher ease of use with SurfCath™. Commercially available purpose-built catheters should facilitate universal adaptation of the MIST method.

Screening for psychosocial risk in caregivers of children with medical complexity during the COVID-19 pandemic: a cross-sectional study

OBJECTIVE

The primary objective was to quantify psychosocial risk in family caregivers (FCs) of children with medical complexity (CMC) during the COVID-19 pandemic using the Psychosocial Assessment Tool (PAT). The secondary objectives were to compare this finding with the average PAT score of this population before the COVID-19 pandemic and to examine potential clinical predictors of psychosocial risk in FCs of CMC.

DESIGN

Cross-sectional study.

PARTICIPANTS

FCs of CMC were recruited from the Long-Term Ventilation Clinic at The Hospital for Sick Children, Toronto, Ontario, Canada. A total of 91 completed the demographic and PAT questionnaires online from 10 June 2021 through 13 December 2021.

MAIN OUTCOME MEASURES

Mean PAT scores in FCs were categorised as 'Universal' low risk, 'Targeted' intermediate risk or 'Clinical' high risk. The effect of sociodemographic and clinical variables on overall PAT scores was assessed using multiple linear regression analysis. Comparisons with a previous study were made using Mann-Whitney tests and χ² analysis.

RESULTS

Mean (SD) PAT score was 1.34 (0.69). Thirty-one (34%) caregivers were classified as Universal, 43 (47%) as Targeted and 17 (19%) as Clinical. The mean PAT score (1.34) was significantly higher compared with the mean PAT score (1.17) found prior to the COVID-19 pandemic. Multiple linear regression analysis demonstrated an overall significant model, with the number of hospital admissions since the onset of COVID-19 being the only variable associated with the overall PAT score.

CONCLUSION

FCs of CMC are experiencing significant psychosocial stress during the COVID-19 pandemic. Timely and effective interventions are warranted to ensure these individuals receive the appropriate support.

LRRC8A anion channels modulate vasodilation via association with Myosin Phosphatase Rho Interacting Protein (MPRIP)

BACKGROUND

In vascular smooth muscle cells (VSMCs), LRRC8A volume regulated anion channels (VRACs) are activated by inflammatory and pro-contractile stimuli including tumor necrosis factor alpha (TNFα), angiotensin II and stretch. LRRC8A physically associates with NADPH oxidase 1 (Nox1) and supports its production of extracellular superoxide (O ₂ ^-• ).

METHODS AND RESULTS

Mice lacking LRRC8A exclusively in VSMCs (Sm22α-Cre, KO) were used to assess the role of VRACs in TNFα signaling and vasomotor function. KO mesenteric vessels contracted normally to KCl and phenylephrine, but relaxation to acetylcholine (ACh) and sodium nitroprusside (SNP) was enhanced compared to wild type (WT). 48 hours of ex vivo exposure to TNFα (10ng/ml) markedly impaired dilation to ACh and SNP in WT but not KO vessels. VRAC blockade (carbenoxolone, CBX, 100 μM, 20 min) enhanced dilation of control rings and restored impaired dilation following TNFα exposure. Myogenic tone was absent in KO rings. LRRC8A immunoprecipitation followed by mass spectroscopy identified 35 proteins that interacted with LRRC8A. Pathway analysis revealed actin cytoskeletal regulation as the most closely associated function of these proteins. Among these proteins, the Myosin Phosphatase Rho-Interacting protein (MPRIP) links RhoA, MYPT1 and actin. LRRC8A-MPRIP co-localization was confirmed by confocal imaging of tagged proteins, Proximity Ligation Assays, and IP/western blots which revealed LRRC8A binding at the second Pleckstrin Homology domain of MPRIP. siLRRC8A or CBX treatment decreased RhoA activity in cultured VSMCs, and MYPT1 phosphorylation at T853 was reduced in KO mesenteries suggesting that reduced ROCK activity contributes to enhanced relaxation. MPRIP was a target of redox modification, becoming oxidized (sulfenylated) after TNFα exposure.

CONCLUSIONS

Interaction of Nox1/LRRC8A with MPRIP/RhoA/MYPT1/actin may allow redox regulation of the cytoskeleton and link Nox1 activation to both inflammation and vascular contractility.

Predictors of Developing Heart Failure in Adults with Congenital Heart Defects

Background

The population of adults with congenital heart defects (ACHD) is growing. The leading cause of premature death in these patients is heart failure (HF). However, there is still limited information on the predictive factors for HF in ACHD patients.

Objectives

This study re-examined a group of patients with repaired or palliated congenital heart defects (CHD) that were initially studied in 2003. A follow-up period of 15 years has allowed us to identify and evaluate predictors for the development of HF in ACHD.

Methods

All patients with repaired or palliated CHD who participated in the initial study (n = 364) were invited for a follow-up examination. The effects of maximum oxygen uptake ( VO 2max ) during exercise stress testing, the cardiac biomarker N-terminal pro brain natriuretic peptide (NT-proBNP), and QRS complex on the development of HF during the follow-up period were investigated.

Results

From May 2017 to April 2019, 249 of the initial 364 (68%) patients participated in the follow-up study. Of these, 21% were found to have mild CHD, 60% had moderate CHD, and 19% had complex CHD. Significant predictors for the development of HF were: NT-proBNP level > 1.7 times the upper normal limit, VO 2max < 73% of predicted values, and QRS complex duration > 120 ms. Combination of these three parameters resulted in the highest area-under-the-curve of 0.75, with a sensitivity of 75% and specificity of 63% for predicting the development of HF.

Conclusions

In this cohort of ACHD patients, the combination of VO 2max% , NT-proBNP, and QRS duration was predictive of HF development over a 15-year follow-up period. Enhanced surveillance of these parameters in patients with ACHD may be beneficial for the prevention of HF and early intervention.

Cross-immunity against SARS-COV-2 variants of concern in naturally infected critically ill COVID-19 patients

Critically ill patients infected with SARS-CoV-2 display adaptive immunity, but it is unknown if they develop cross-reactivity to variants of concern (VOCs). We profiled cross-immunity against SARS-CoV-2 VOCs in naturally infected, non-vaccinated, critically ill COVID-19 patients. Wave-1 patients (wild-type infection) were similar in demographics to Wave-3 patients (wild-type/alpha infection), but Wave-3 patients had higher illness severity. Wave-1 patients developed increasing neutralizing antibodies to all variants, as did patients during Wave-3. Wave-3 patients, when compared to Wave-1, developed more robust antibody responses, particularly for wild-type, alpha, beta and delta variants. Within Wave-3, neutralizing antibodies were significantly less to beta and gamma VOCs, as compared to wild-type, alpha and delta. Patients previously diagnosed with cancer or chronic obstructive pulmonary disease had significantly fewer neutralizing antibodies. Naturally infected ICU patients developed adaptive responses to all VOCs, with greater responses in those patients more likely to be infected with the alpha variant, versus wild-type.

Novel plasma protein biomarkers from critically ill sepsis patients

BACKGROUND

Despite the high morbidity and mortality associated with sepsis, the relationship between the plasma proteome and clinical outcome is poorly understood. In this study, we used targeted plasma proteomics to identify novel biomarkers of sepsis in critically ill patients.

METHODS

Blood was obtained from 15 critically ill patients with suspected/confirmed sepsis (Sepsis-3.0 criteria) on intensive care unit (ICU) Day-1 and Day-3, as well as age- and sex-matched 15 healthy control subjects. A total of 1161 plasma proteins were measured with proximal extension assays. Promising sepsis biomarkers were narrowed with machine learning and then correlated with relevant clinical and laboratory variables.

RESULTS

The median age for critically ill sepsis patients was 56 (IQR 51-61) years. The median MODS and SOFA values were 7 (IQR 5.0-8.0) and 7 (IQR 5.0-9.0) on ICU Day-1, and 4 (IQR 3.5-7.0) and 6 (IQR 3.5-7.0) on ICU Day-3, respectively. Targeted proteomics, together with feature selection, identified the leading proteins that distinguished sepsis patients from healthy control subjects with ≥ 90% classification accuracy; 25 proteins on ICU Day-1 and 26 proteins on ICU Day-3 (6 proteins overlapped both ICU days; PRTN3, UPAR, GDF8, NTRK3, WFDC2 and CXCL13). Only 7 of the leading proteins changed significantly between ICU Day-1 and Day-3 (IL10, CCL23, TGFα1, ST2, VSIG4, CNTN5, and ITGAV; P < 0.01). Significant correlations were observed between a variety of patient clinical/laboratory variables and the expression of 15 proteins on ICU Day-1 and 14 proteins on ICU Day-3 (P < 0.05).

CONCLUSIONS

Targeted proteomics with feature selection identified proteins altered in critically ill sepsis patients relative to healthy control subjects. Correlations between protein expression and clinical/laboratory variables were identified, each providing pathophysiological insight. Our exploratory data provide a rationale for further hypothesis-driven sepsis research.

Enteral supplementation with probiotics in preterm infants: A retrospective cohort study and 6-year follow-up

The objective of this retrospective cohort study was to assess the impact of an enteral probiotics supplementation protocol on the incidence of necrotizing enterocolitis (NEC) in infants born <33 weeks gestational age (GA) or birth weight (BW) <1,500 g. In addition, a 6-year follow-up is presented after instigation of probiotic use. In October 2014, our NICU introduced an enteral probiotics supplementation protocol for infants born <33 weeks GA or BW <1,500 g. Infants received 0.5 g of Bifidobacterium breve HA-129, Lacticaseibacillus rhamnosus HA-111, Bifidobacterium bifidum HA-132, Bifidobacterium longum subsp. infantis HA-116, and Bifidobacterium longum subsp. longum HA-135 (FloraBABY^Ⓡ) daily until discharge or transfer from hospital. The incidence of NEC was compared among infants for 2 years pre- and post implementation of the protocol then 6-years following continuous implementation of the probiotic use. In total, 370 infants not treated with probiotics between 2012 and 2014 were included with an incidence of NEC at 4.9%. In comparison, the 367 infants who received had a 67% reduction (4.9-1.6%, p = 0.01) in our Neonatal Intensive Care Unit (NICU). The results remained significant (aOR = 0.26; 95% CI: 0.09, 0.72; p < 0.01) after adjusting for GA, small for gestational age, and antenatal corticosteroid use. Data from the Canadian Neonatal Network not only showed a consistently high rate of NEC in October 2014, but also identified exceedingly high rates (8.7-15.6%) in some hospitals up to 2021, while our rates have been consistently low with using the probiotic as standard therapy for low BW premature babies, with no serious side effects reported. In conclusion, the introduction of a five-strain probiotic natural health product has coincided with a reduced incidence and complications of NEC in our NICU setting.

Laryngeal Mask Airway for Surfactant Administration Versus Standard Treatment Methods in Preterm Neonates with Respiratory Distress Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

Laryngeal mask airway (LMA) has emerged as an alternative surfactant delivery method. The effectiveness of this method for the delivery of surfactant is uncertain. A meta-analysis of randomized control trials (RCTs) comparing LMA with standard methods of surfactant delivery for the outcomes of surfactant dose repetition, oxygen requirement, mechanical ventilation, intubation, mortality, bronchopulmonary dysplasia (BPD), and pneumothorax.

STUDY DESIGN

Systematic review and meta-analysis of RCTs. Homogeneity between studies was analyzed by using I² statistics. Risk ratio or mean difference of outcomes was assessed from random effects models. Subgroup analyses were conducted when necessary. Data sources are as follows: Ovid Medline, Embase, and the Cochrane Central Register of Controlled trials from inception till December 2018, bibliographies of identified reviews and trial registries for ongoing studies. RCTs comparing short-term respiratory outcomes in neonates with respiratory distress syndrome who were administered surfactant through an LMA versus standard method of care.

RESULTS

Six RCTs were identified, enrolling a total of 357 infants. Administering surfactant via LMA was associated with decreased FiO₂ requirement (mean difference = 1.82 (95% confidence interval [CI]: -6.01-9.66), decreased intubation (risk ratio [RR] = 0.17; 95% CI: 0.05-0.57), and decreased mechanical ventilation (RR = 0.44; 95% CI: 0.31-0.61). There were no significant differences between groups for death, BPD, or pneumothorax.

CONCLUSION

LMA might be an effective alternative method of surfactant delivery; however, further high-quality RCTs with larger sample size and including extreme preterm infants are needed to establish LMA as an alternative technique for surfactant delivery.

KEY POINTS

· Pulmonary surfactants reduce mortality and pulmonary air leaks in newborns with respiratory distress syndrome.. · Preterm lungs are at risk of volutrauma by mechanical ventilation; laryngoscopy is still traumatic.. · Surfactant administration via LMA to avoid mechanical ventilation and intubation might be feasible..