Rapid unleashing of macrophage efferocytic capacity via transcriptional pause release.

During development, inflammation or tissue injury, macrophages may successively engulf and process multiple apoptotic corpses via efferocytosis to achieve tissue homeostasis1. How macrophages may rapidly adapt their transcription to achieve continuous corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved mechanism, in which RNA polymerase (Pol) II initiates transcription for 20-60 nucleotides, is paused for minutes to hours and is then released to make full-length mRNA2. Here we show that macrophages, within minutes of corpse encounter, use transcriptional pause/release to unleash a rapid transcriptional response. For human and mouse macrophages, the Pol II pause/release was required for continuous efferocytosis in vitro and in vivo. Interestingly, blocking Pol II pause/release did not impede Fc receptor-mediated phagocytosis, yeast uptake or bacterial phagocytosis. Integration of data from three genomic approaches-precision nuclear run-on sequencing, RNA sequencing, and assay for transposase-accessible chromatin using sequencing (ATAC-seq)-on efferocytic macrophages at different time points revealed that Pol II pause/release controls expression of select transcription factors and downstream target genes. Mechanistic studies on transcription factor EGR3, prominently regulated by pause/release, uncovered EGR3-related reprogramming of other macrophage genes involved in cytoskeleton and corpse processing. Using lysosomal probes and a new genetic fluorescent reporter, we identify a role for pause/release in phagosome acidification during efferocytosis. Furthermore, microglia from egr3-deficient zebrafish embryos displayed reduced phagocytosis of apoptotic neurons and fewer maturing phagosomes, supporting defective corpse processing. Collectively, these data indicate that macrophages use Pol II pause/release as a mechanism to rapidly alter their transcriptional programs for efficient processing of the ingested apoptotic corpses and for successive efferocytosis.

Timeline of diagnosed pain causes in children with severe neurological impairment.

Objective: Pain's causes in children with severe cognitive impairment may be challenging to diagnose. This study aimed to investigate if there is a relationship between pain causes and the age of children. Methods: We conducted a multicenter retrospective study in three Italian Pediatric Units. Eligible subjects were patients from 1 to 18 years with severe neurological impairment. We collected data regarding diagnoses, pain causes and medical or surgical procedures. The timing of pain episodes was categorized into age-related periods: infants and toddlers (0-24 months), preschool children (3-5 years), schoolchildren (6-12 years), and adolescents (13-17 years). Results: Eighty children with severe neurological impairment were enrolled. The mean age was 11 years (±5.8). Gastroenterological pain was most common in the first years of life (p = 0.004), while orthopaedic and tooth pain was the most typical in schoolchildren and adolescents (p = 0.001 and p = 0.02). Concerning surgical procedures, PEG placement and gastric fundoplication were significantly more common in the first 5 years of age (p = 0.03), and heart surgery was typical of infants (p = 0.04). Orthopaedic surgery was more commonly reported in older children and adolescents (p < 0.001). Conclusions: Some causes of pain are more frequent in children with severe neurological impairment in defined age-related periods. Specific age-related pain frequencies may help physicians in the diagnostic approach.

Urgent Hospitalizations Related to Viral Respiratory Disease in Children during Autumn and Winter Seasons 2022/2023.

AIM: The loosening of social distancing measures over the past two years has led to a resurgence of seasonal epidemics associated with respiratory viral infections in children. We aim to describe the impact of such infections through urgent hospitalizations in a pediatric emergency department. METHODS: We performed a retrospective review of medical records of all children and adolescents with a positive nasal swab admitted at the children's hospital IRCCS Burlo Garofolo of Trieste, in Italy, from September 2021 to March 2022, and September 2022 to March 2023. RESULTS: Respiratory Syncytial Virus and Influenza viruses accounted for up to 55% of hospitalizations for respiratory infections during the study periods. During the last season, the number of hospitalizations related to the Influenza virus was five times higher than those related to SARS-CoV-2 (25% vs. 5%). Respiratory Syncytial Virus was associated with a greater need for respiratory support, mostly HFNC (High Flow Nasal Cannula). CONCLUSIONS: Respiratory Syncytial Virus and Influenza virus had a more significant impact on urgent hospitalizations during the past wintery seasons than SARS-CoV-2.

Hematopoietic Stem Cells Transplant (HSCT)-Related Chronic Pulmonary Diseases: An Overview.

Recipients of HSCT have a high risk of infective and non-infective pulmonary diseases. Most patients with pulmonary involvement present multiple pathogenetic mechanisms simultaneously with complex interactions. Therefore, it can be difficult to distinguish the contributions of each one and to perform studies on this subject. In this opinion article, we discuss only chronic pulmonary manifestations, focusing on LONIPCs (late-onset non-infectious pulmonary complications). This term embraces drug-related toxicity, allergies, and chronic pulmonary graft versus host disease (GvHD) in all its recently identified clinical variants. Among LONIPCs, GvHD represents the most critical in terms of morbidity and mortality, despite the rapid development of new treatment options. A recently emerging perspective suggests that pulmonary lung rejection in transplant patients shares striking similarities with the pathogenesis of GvHD. In a pulmonary transplant, the donor organ is damaged by the host immune system, whereas in GvHD, the donor immune system damages the host organs. It constitutes the most significant breakthrough in recent years and is highly promising for both hematologists and thoracic transplant surgeons. The number of patients with LONIPCs is scarce, with heterogenous clinical characteristics often involving several pathogenetic mechanisms, making it challenging to conduct randomized controlled trials. Therefore, the body of evidence in this field is scarce and generally of low quality, leading to jeopardized choices in terms of immunosuppressive treatment. Moreover, it risks being outdated by common practice due to the quick evolution of knowledge about the diagnosis and treatment of LONIPCs. The literature is even more pitiful for children with pulmonary involvement related to HSCT.

Seizure-induced increase in microglial cell population in the developing zebrafish brain.

Epilepsy is a chronic brain disorder characterized by unprovoked and recurrent seizures, of which 60% are of unknown etiology. Recent studies implicate microglia in the pathophysiology of epilepsy. However, their role in this process, in particular following early-life seizures, remains poorly understood due in part to the lack of suitable experimental models allowing the in vivo imaging of microglial activity. Given the advantage of zebrafish larvae for minimally-invasive imaging approaches, we sought for the first time to describe the microglial responses after acute seizures in two different zebrafish larval models: a chemically-induced epileptic model by the systemic injection of kainate at 3 days post-fertilization, and the didys552 genetic epilepsy model, which carries a mutation in scn1lab that leads to spontaneous epileptiform discharges. Kainate-treated larvae exhibited transient brain damage as shown by increased numbers of apoptotic nuclei as early as one day post-injection, which was followed by an increase in the number of microglia in the brain. A similar microglial phenotype was also observed in didys552-/- mutants, suggesting that microglia numbers change in response to seizure-like activity in the brain. Interestingly, kainate-treated larvae also displayed a decreased seizure threshold towards subsequent pentylenetetrazole-induced seizures, as shown by higher locomotor and encephalographic activity in comparison with vehicle-injected larvae. These results are comparable to kainate-induced rodent seizure models and suggest the suitability of these zebrafish seizure models for future studies, in particular to elucidate the links between epileptogenesis and microglial dynamic changes after seizure induction in the developing brain, and to understand how these modulate seizure susceptibility.

Drowning in Children and Predictive Parameters: A 15-Year Multicenter Retrospective Analysis.

BACKGROUND: Drowning is a serious and underestimated public health problem, with the highest morbidity and mortality reported among children. Data regarding pediatric outcomes of drowning are often inadequate, and data collection is poorly standardized among centers. This study aims to provide an overview of a drowning pediatric population in pediatric emergency department, focusing on its main characteristics and management and evaluating prognostic factors. METHODS: This is a retrospective multicenter study involving eight Italian Pediatric Emergency Departments. Data about patients between 0 to 16 years of age who drowned between 2006 and 2021 were collected and analyzed according to the Utstein-style guidelines for drowning. RESULTS: One hundred thirty-five patients (60.9% males, median age at the event 5; interquartile range, 3-10) were recruited and only those with known outcome were retained for the analysis (133). Nearly 10% had a preexisting medical conditions with epilepsy being the most common comorbidity. One third were hospitalized in the intensive care unit (ICU) and younger males had a higher rate of ICU admission than female peers. Thirty-five patients (26.3%) were hospitalized in a medical ward while 19 (14.3%) were discharged from the emergency department and 11 (8.3%) were discharged after a brief medical observation less than 24 hours. Six patients died (4.5%). Medium stay in the ED was approximately 40 hours. No difference in terms of ICU admission was found between cardiopulmonary resuscitation performed by bystanders or trained medical personnel ( P = 0.388 vs 0.390). CONCLUSIONS: This study offers several perspectives on ED victims who drowned. One of the major finding is that no difference in outcomes was seen in patients who received cardiopulmonary resuscitation performed by bystanders or medical services, highlighting the importance of a prompt intervention.

T2-Low Asthma: A Discussed but Still Orphan Disease.

Asthma affects 10% of the worldwide population; about 5% of cases are severe with the need for target therapies such as biologics. All the biologics approved for asthma hit the T2 pathway of inflammation. T2-high asthma is classified as allergic and non-allergic, whereas T2-low asthma can be further defined as paucigranulocytic asthma, Type 1 and Type-17 inflammation and the neutrophilic form that accounts for 20-30% of all patients with asthma. Neutrophilic asthma's prevalence is even higher in patients with severe or refractory asthma. We searched Medline and PubMed archives from the past ten years for articles with the subsequent titles: "neutrophilic asthma", "non-type 2 asthma" and "paucigranulocytic asthma". We identified 177 articles; 49 were considered relevant by the title and 33 by the reading of the abstract. Most of these articles are reviews (n = 19); only 6 are clinical trials. No study identified an effective treatment. We used the literature reported by these articles to search for further biologic treatments that target pathways different from T2. We identified 177 articles, 93 of which were considered relevant for the review and included in the present article. In conclusion, T2-low asthma remains poorly investigated in terms of biomarkers, especially as a therapeutic orphan disease.

Transient Receptor Potential Ankyrin 1 (TRPA1) Methylation and Chronic Pain: A Systematic Review.

BACKGROUND AND OBJECTIVE: Chronic pain represents a major global health issue in terms of psycho-physiological, therapeutic, and economic burden, not limited to adults but also to the pediatric age. Despite its great impact, its molecular mechanisms have still not been completely unraveled. Focusing on the impact of epigenetics in the pain complex trait, we assessed the association between chronic pain and the methylation pattern of TRPA1, a key gene related to pain sensitivity. METHODS: We conducted a systematic review retrieving articles from three different databases. After deduplication, 431 items were subjected to manual screening, and then 61 articles were selected and screened again. Of these, only six were maintained for meta-analysis and analyzed using specific R packages. RESULTS: Six articles were divided into two groups (group 1: comparison of mean methylation levels between healthy subjects and patients with chronic pain; group 2: correlation between mean methylation levels and pain sensation). A non-significant mean difference was obtained from the analysis of group 1 with a value of 3.97 (95% C.I. -7.79; 15.73). Analysis of group 2 showed a high level of variability between studies (correlation = 0.35, 95% C.I. -0.12; 0.82) due to their heterogeneity (I2 = 97%, p < 0.01). CONCLUSIONS: Despite the high variability observed in the different studies analyzed, our results suggest that hypermethylation and increased pain sensitivity could be connected, possibly due to the variation of TRPA1 expression.

A role for the centrosome in regulating the rate of neuronal efferocytosis by microglia in vivo.

During brain development, many newborn neurons undergo apoptosis and are engulfed by microglia, the tissue-resident phagocytes of the brain, in a process known as efferocytosis. A hallmark of microglia is their highly branched morphology characterized by the presence of numerous dynamic extensions that these cells use for scanning the brain parenchyma and engulfing unwanted material. The mechanisms driving branch formation and apoptotic cell engulfment in microglia are unclear. By taking a live-imaging approach in zebrafish, we show that while microglia generate multiple microtubule-based branches, they only successfully engulf one apoptotic neuron at a time. Further investigation into the mechanism underlying this sequential engulfment revealed that targeted migration of the centrosome into one branch is predictive of phagosome formation and polarized vesicular trafficking. Moreover, experimentally doubling centrosomal numbers in microglia increases the rate of engulfment and even allows microglia to remove two neurons simultaneously, providing direct supporting evidence for a model where centrosomal migration is a rate-limiting step in branch-mediated efferocytosis. Conversely, light-mediated depolymerization of microtubules causes microglia to lose their typical branched morphology and switch to an alternative mode of engulfment, characterized by directed migration towards target neurons, revealing unexpected plasticity in their phagocytic ability. Finally, building on work focusing on the establishment of the immunological synapse, we identified a conserved signalling pathway underlying centrosomal movement in engulfing microglia.

Severe Pediatric Asthma Therapy: Mepolizumab.

There is a growing need for advanced treatment in children with persistent and severe asthma symptoms. As a matter of fact, between 2 and 5% of asthmatic children experience repeated hospitalizations and poor quality of life despite optimized treatment with inhaled glucocorticoid plus a second controller. In this scenario, mepolizumab, a humanized monoclonal antibody, has proven to be effective in controlling eosinophil proliferation by targeting interleukin-5 (IL-5), a key mediator of eosinophil activation pathways. Mepolizumab is approved since 2015 for adults at a monthly dose of 100 mg subcutaneously and it has been approved for patients ≥ 6 years of age in 2019. Especially in children aged 6 to 11 years, mepolizumab showed a greater bioavailability, with comparable pharmacodynamics parameters as in the adult population. The recommended dose of 40 mg every 4 weeks for children aged 6 through 11 years, and 100 mg for patients ≥ 12 years provides appropriate concentration and proved similar therapeutic effects as in the adult study group. A marked reduction in eosinophil counts clinically reflects a significant improvement in asthma control as demonstrated by validated questionnaires, reduction of exacerbation rates, and the number of hospitalizations. Finally, mepolizumab provides a safety and tolerability profile similar to that observed in adults with adverse events mostly of mild or moderate severity. The most common adverse events were headache and injection-site reaction. In conclusion, mepolizumab can be considered a safe and targeted step-up therapy for severe asthma with an eosinophilic phenotype in children and adolescents.

WHO standards-based tools to measure service providers' and service users' views on the quality of hospital child care: development and validation in Italy.

OBJECTIVES: Evidence showed that, even in high-income countries, children and adolescents may not receive high quality of care (QOC). We describe the development and initial validation, in Italy, of two WHO standards-based questionnaires to conduct an assessment of QOC for children and young adolescents at inpatient level, based on the provider and user perspectives. DESIGN: Multiphase, mixed-methods study. SETTING, PARTICIPANTS AND METHODS: The two questionnaires were developed in four phases equally conducted for each tool. Phase 1 which included the prioritisation of the WHO Quality Measures according to predefined criteria and the development of the draft questionnaires. In phase 2 content face validation of the draft questionnaires was assessed among both experts and end-users. In phase 3 the optimised questionnaires were field tested to assess acceptability, perceived utility and comprehensiveness (N=163 end-users). In phase 4 intrarater reliability and internal consistency were evaluated (N=170 and N=301 end-users, respectively). RESULTS: The final questionnaires included 150 WHO Quality Measures. Observed face validity was excellent (kappa value of 1). The field test resulted in response rates of 98% and 76% for service users and health providers, respectively. Among respondents, 96.9% service users and 90.4% providers rated the questionnaires as useful, and 86.9% and 93.9%, respectively rated them as comprehensive. Intrarater reliability was good, with Cohen's kappa values exceeding 0.70. Cronbach alpha values ranged from 0.83 to 0.95, indicating excellent internal consistency. CONCLUSIONS: Study findings suggest these tools developed have good content and face validity, high acceptability and perceived utility, and good intrarater reliability and internal consistency, and therefore could be used in health facilities in Italy and similar contexts. Priority areas for future research include how tools measuring paediatric QOC can be more effectively used to help health professionals provide the best possible care.

A well-appearing infant with a sudden anisocoria.

Case presentationA 10-month-old boy was admitted to the emergency department due to a sudden onset of left unilateral mydriasis (figure 1). His medical history was unremarkable. A minor head trauma 2 days before was reported, without alarming signs or symptoms. His mother was putting him to sleep, after coming back from work, when she noticed a different pupil size and promptly went to the ED with her husband. The parents denied any use of medications, including nebulised therapy or direct contact with plants. The child was well appearing and his vital signs were within the standard age limits. His extraocular motility was normal as well as the rest of his neurological and physical examination. Parents' behaviour was somehow remarkable. Even though the child was not suffering, the mother seemed very worried while the father was nervous and aggressive, repeatedly asking for a discharge.

Microglial 'fat shaming' in development and disease.

Neuronal-immune interactions are known to play crucial roles in brain development and homoeostasis. Of great relevance in this context are microglia, brain macrophages that phagocytose neurons that die during development, and many neurological disorders. Single-cell RNA sequencing methods have significantly advanced our understanding of microglial heterogeneity and transcriptional response to environmental changes. Here, we review recent work showing how microglia adopt a similar molecular signature during development and disease characterised by the expression of genes linked to phagocytosis and lipid uptake and metabolism. These studies show that in many neurodegenerative conditions, microglia accumulate cholesterols and lipid-rich debris, pointing to lipid processing and transport as promising targets for developing new therapeutical treatments against neurodegenerative disorders.

Venipuncture activates the cerebral cortex in children with intellectual disability.

OBJECTIVE: To evaluate the pattern of cortical activation during a painful procedure, such as a venipuncture, in children with intellectual disability and compare it with that of cognitively healthy children. STUDY DESIGN AND SETTING: A cohort study was conducted and cortical activation was assessed by multichannel cerebral near-infrared spectroscopy to monitor variations in oxyhaemoglobin and deoxyhaemoglobin (Hbb) in children with and without intellectual disability during a venipuncture for blood sampling with topical anaesthesia. Pain and distress were assessed as well using different validated pain scales (visual analogue scale and Non-Communicating Children's Pain Checklist-Postoperative Version for children with intellectual disability), and compared between groups. PARTICIPANTS: 16 children with severe to profound intellectual disability and 20 cognitively healthy peers (age range: 4-17 years). RESULTS: When Hbb was analysed, children with intellectual disability exhibited a bilateral activation of the somatosensory (p<0.006) and right motor cortex (p=0.0045), whereas cognitively healthy peers never showed a cortical activation. Children with intellectual disability also showed more pain than controls (p=0.001). CONCLUSIONS: When subjected to a painful procedure, only children with intellectual disability show an activation of the cerebral cortex, even if topical anaesthesia is applied, and express more pain than cognitively healthy peers. The role of other issues in painful procedures, such as anxiety, fear or physical restraint, deserves further investigation.