The Efficacy of Noninvasive Ventilation in Patients Affected by Rett Syndrome With Hypoventilation.

BACKGROUND: Rett syndrome is a progressive neurological disorder associated to several comorbidities that contribute significantly to impair lung function. Respiratory morbidity represents a major cause of death in this population. Little is known about the benefit of noninvasive ventilation. METHODS: We retrospectively enrolled patients with Rett syndrome who underwent a pneumological evaluation combined with a cardiorespiratory polygraphy and/or a pulse oximetry and capnography from 2012 to 2022. RESULTS: Medical records of 11 patients with Rett syndrome, mean age 13 ± 6 years, were evaluated. Most patients presented with both epilepsy and scoliosis. Five patients showed a pathologic sleep study and/or impaired night gas exchange: mean obstructive apnea-hypopnea index was 4 ± 3 events/hour; mean and minimal SpO2 were, respectively, 93% ± 2% and 83% ± 6%, while mean and maximal transcutaneous carbon dioxide monitoring (PtcCO2) were, respectively, 51 ± 5 mm Hg and 55 ± 8 mm Hg; and mean oxygen desaturation index was 13 ± 11 events/hour. These patients started noninvasive ventilation with clinical benefit and improved gas exchange mostly in terms of PtcCO2 (mean PtcCO2 51 ± 5 mm Hg before and 46 ± 6 mm Hg after noninvasive ventilation). CONCLUSIONS: Noninvasive ventilation is a suitable option for patients with Rett syndrome.

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.

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.

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.

Rapid clearance of cellular debris by microglia limits secondary neuronal cell death after brain injury in vivo.

Moderate or severe traumatic brain injury (TBI) causes widespread neuronal cell death. Microglia, the resident macrophages of the brain, react to injury by migrating to the lesion site, where they phagocytose cellular debris. Microglial phagocytosis can have both beneficial (e.g. debris clearance) and detrimental (e.g. respiratory burst, phagoptosis) consequences. Hence, whether the overall effect of microglial phagocytosis after brain injury in vivo is neuroprotective or neurotoxic is not known. Here, we establish a system with which to carry out dynamic real-time analyses of the mechanisms regulating cell death after brain injury in vivo We show that mechanical injury to the larval zebrafish brain induces distinct phases of primary and secondary cell death. Excitotoxicity contributes to secondary cell death in zebrafish, reflecting findings from mammals. Microglia arrive at the lesion site within minutes of injury, where they rapidly engulf dead cells. Importantly, the rate of secondary cell death is increased when the rapid removal of cellular debris by microglia is reduced pharmacologically or genetically. In summary, our results provide evidence that microglial debris clearance is neuroprotective after brain injury in vivo.

Clearance by Microglia Depends on Packaging of Phagosomes into a Unique Cellular Compartment.

Phagocytic immune cells such as microglia can engulf and process pathogens and dying cells with high efficiency while still maintaining their dynamic behavior and morphology. Effective intracellular processing of ingested cells is likely to be crucial for microglial function, but the underlying cellular mechanisms are poorly understood. Using both living fish embryos and mammalian macrophages, we show that processing depends on the shrinkage and packaging of phagosomes into a unique cellular compartment, the gastrosome, with distinct molecular and ultra-structural characteristics. Loss of the transporter Slc37a2 blocks phagosomal shrinkage, resulting in the expansion of the gastrosome and the dramatic bloating of the cell. This, in turn, affects the ability of microglia to phagocytose and migrate toward brain injuries. Thus, this work identifies a conserved crucial step in the phagocytic pathway of immune cells and provides a potential entry point for manipulating their behavior in development and disease.

The SLC7A7 Transporter Identifies Microglial Precursors prior to Entry into the Brain.

During development, macrophages invade organs to establish phenotypically and transcriptionally distinct tissue-resident populations. How they invade and colonize these organs is unclear. In particular, it remains to be established whether they arise from naive equivalents that colonize organs randomly or whether there are committed macrophages that follow pre-determined migration paths. Here, by using a combination of genetics and imaging approaches in the zebrafish embryo, we have addressed how macrophages colonize the brain to become microglia. Identification and cloning of a mutant that lacks microglia has shown that Slc7a7, a Leucine/Arginine transporter, defines a restricted macrophage sub-lineage and is necessary for brain colonization. By taking a photoconversion approach, we show that these macrophages give rise to microglia. This study provides direct experimental evidence for the existence of sub-lineages among embryonic macrophages.

Microglia: multitasking specialists of the brain.

Microglia are macrophages that colonize the brain during development to establish a resident population of professional phagocytes that protect against invading pathogens and contribute to brain development and homeostasis. As such, these cells sit at the interface between immunology and neurobiology. In addition to their key roles in brain physiology, microglia offer a great opportunity to address central questions in biology relating to how migrating cells find their positions in the embryo, adopt a behavior that is appropriate for that position, and interact with their local environment. We aim, in this review, to survey key recent advances in microglial research.

Impact of Highly Active Antiretroviral Therapy on the Natural History of Cervical Precancerous Lesions: A 17-Year Institutional Longitudinal Cohort Study.

We performed an observational cohort study in order to assess the correlation between precancerous cervical lesions (cervical intraepithelial neoplasia [CIN]) and immunological state in human immunodeficiency virus (HIV)-positive women treated by highly active antiretroviral therapy (HAART). We analyzed 194 HIV-infected women referred to the Parma-Universitary Hospital for early detection of human papilloma virus-induced CINs. We analyzed cytology, colposcopy, and CIN degree according to HAART: group A untreated and group B treated. We compared the CD4+ count and viral load at the time of CIN onset and the time interval between diagnosis of HIV and the onset of CIN. Group A and group B showed homogeneous results for general features, CD4+ count, viral load, and Papanicolaou test features. Differences were not found in terms of histology and CD4+ value, viral load count, pharmacological treatment, years since the diagnosis of HIV, age, smoking, sexual promiscuity, previous intravenous narcotics abuse, prostitution, sexually transmitted diseases, ethnicity, and age at diagnosis. Histology and the clinical stage of HIV showed significant concordances between the high degree of cervical dysplasia and advanced stage of HIV disease.

Risk of preterm delivery associated with prior treatment of cervical precancerous lesion according to the depth of the cone.

The aim of this study was to evaluate the impact of the surgical excisional procedures for cervical intraepithelial neoplasia (CIN) treatment both on subsequent fertility (cervical factor) and pregnancy complication (risk of spontaneous preterm delivery). We retrospectively analyzed 236 fertile women who underwent conization for CIN. We included in the study 47 patients who carried on pregnancy and delivered a viable fetus. Patients were asked about postconization pregnancies, obstetrical outcomes, and a possible diagnosis of secondary infertility caused by cervical stenosis. We evaluated the depth of surgical excision, the timing between cervical conization and subsequent pregnancies, surgical technique, and maternal age at delivery. We recorded 47 deliveries, 10 cases of preterm delivery; 8 of them were spontaneous. The depth of surgical excision showed a statistically significant inverse correlation with gestational age at birth. The risk of spontaneous preterm delivery increased when conization depth exceeded a cut-off value of 1.5 cm. Our data do not demonstrated a relation between conization and infertility due to cervical stenosis.

Long-range Ca2+ waves transmit brain-damage signals to microglia.

Microglia are the resident phagocytes of the brain that are responsible for the clearance of injured neurons, an essential step in subsequent tissue regeneration. How death signals are controlled both in space and time to attract these cells toward the site of injury is a topic of great interest. To this aim, we have used the optically transparent zebrafish larval brain and identified rapidly propagating Ca2+ waves that determine the range of microglial responses to neuronal cell death. We show that while Ca2+-mediated microglial responses require ATP, the spreading of intercellular Ca2+ waves is ATP independent. Finally, we identify glutamate as a potent inducer of Ca2+-transmitted microglial attraction. Thus, this real-time analysis reveals the existence of a mechanism controlling microglial targeted migration to neuronal injuries that is initiated by glutamate and proceeds across the brain in the form of a Ca2+ wave.

Breaking ranks: how leukocytes react to developmental cues and tissue injury.

Leukocytes are arguably the most motile cells in metazoans. Besides their well-described ability to migrate rapidly toward sites of tissue injury, tissue-specific macrophages migrate already during embryogenesis, when they take up residence in a wide range of organs. The recent identification of molecules responsible for the guidance of leukocytes during development and in response to injury has revealed that these modes of migration are under the control of surprisingly different signaling systems. While the developmental migrations are regulated by hard-wired pre-patterns of secreted proteins, the rapid acute response to injury involves signals like hydrogen peroxide or extracellular nucleotides such as ATP. Ongoing work aims to understand how these distinct signals are integrated in the cell to determine different cellular responses.

Tissue macrophages act as cellular chaperones for vascular anastomosis downstream of VEGF-mediated endothelial tip cell induction.

Blood vessel networks expand in a 2-step process that begins with vessel sprouting and is followed by vessel anastomosis. Vessel sprouting is induced by chemotactic gradients of the vascular endothelial growth factor (VEGF), which stimulates tip cell protrusion. Yet it is not known which factors promote the fusion of neighboring tip cells to add new circuits to the existing vessel network. By combining the analysis of mouse mutants defective in macrophage development or VEGF signaling with live imaging in zebrafish, we now show that macrophages promote tip cell fusion downstream of VEGF-mediated tip cell induction. Macrophages therefore play a hitherto unidentified and unexpected role as vascular fusion cells. Moreover, we show that there are striking molecular similarities between the pro-angiogenic tissue macrophages essential for vascular development and those that promote the angiogenic switch in cancer, including the expression of the cell-surface proteins TIE2 and NRP1. Our findings suggest that tissue macrophages are a target for antiangiogenic therapies, but that they could equally well be exploited to stimulate tissue vascularization in ischemic disease.

Mechanisms of Gurken-dependent pipe regulation and the robustness of dorsoventral patterning in Drosophila.

The restriction of Pipe, a potential glycosaminoglycan-modifying enzyme, to ventral follicle cells of the egg chamber is essential for dorsoventral axis formation in the Drosophila embryo. pipe repression depends on the TGFalpha-like ligand Gurken, which activates the Drosophila EGF receptor in dorsal follicle cells. An analysis of Raf mutant clones shows that EGF signalling is required cell-autonomously in all dorsal follicle cells along the anteroposterior axis of the egg chamber to repress pipe. However, the autoactivation of EGF signalling important for dorsal follicle cell patterning has no influence on pipe expression. Clonal analysis shows that also the mirror-fringe cassette suggested to establish a secondary signalling centre in the follicular epithelium is not involved in pipe regulation. These findings support the view that the pipe domain is directly delimited by a long-range Gurken gradient. Pipe induces ventral cell fates in the embryo via activation of the Spätzle/Toll pathway. However, large dorsal patches of ectopic pipe expression induced by Raf clones rarely affect embryonic patterning if they are separated from the endogenous pipe domain. This indicates that potent inhibitory processes prevent pipe dependent Toll activation at the dorsal side of the egg.