The Influence of Neurotrophins on the Brain-Lung Axis: Conception, Pregnancy, and Neonatal Period.

Neurotrophins (NTs) are four small proteins produced by both neuronal and non-neuronal cells; they include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). NTs can exert their action through both genomic and non-genomic mechanisms by interacting with specific receptors. Initial studies on NTs have identified them only as functional molecules of the nervous system. However, recent research have shown that some tissues and organs (such as the lungs, skin, and skeletal and smooth muscle) as well as some structural cells can secrete and respond to NTs. In addition, NTs perform several roles in normal and pathological conditions at different anatomical sites, in both fetal and postnatal life. During pregnancy, NTs are produced by the mother, placenta, and fetus. They play a pivotal role in the pre-implantation process and in placental and embryonic development; they are also involved in the development of the brain and respiratory system. In the postnatal period, it appears that NTs are associated with some diseases, such as sudden infant death syndrome (SIDS), asthma, congenital central hypoventilation syndrome (CCHS), and bronchopulmonary dysplasia (BPD).

Biochemical and genetic tools to predict the progression to Cystic Fibrosis in CRMS/CFSPID subjects: A systematic review.

OBJECTIVES: Aim of this study was to identify risk factors for a progression to cystic fibrosis (CF) in individuals detected as CF Screening Positive, Inconclusive Diagnosis (CFSPID). METHODS: This is a systematic review through literature databases (2015-2023). Blood immunoreactive trypsinogen (b-IRT) values, CFTR genotype, sweat chloride (SC) values, isolation of Pseudomonas aeruginosa (Pa) from respiratory samples, Lung Clearance Index (LCI) values in CFSPIDs who converted to CF (CFSPID > CF) and age at CF transition were assessed. RESULTS: Percentage of CFSPID > CF varies from 5.3 % to 44 %. Presence of one CF-causing CFTR variant in trans with a variant with variable clinical consequences (VVCC), an initial SC ≥ 40 mmol/L, an increase of SC > 2.5 mmol/L/year and recurrent isolation of pseudomonas aeruginosa (Pa) from airway samples could allow identification of subjects at risk of progression to CF. CONCLUSIONS: CFSPIDs with CF causing variant/VVCC genotype and first SC in the higher borderline range may require more frequent and prolonged clinical follow-up.

Immune Response to Respiratory Viral Infections.

The respiratory system is constantly exposed to viral infections that are responsible for mild to severe diseases. In this narrative review, we focalized the attention on respiratory syncytial virus (RSV), influenza virus, and severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infections, responsible for high morbidity and mortality in the last decades. We reviewed the human innate and adaptive immune responses in the airways following infection, focusing on a particular population: newborns and pregnant women. The recent Coronavirus disease-2019 (COVID-19) pandemic has highlighted how our interest in viral pathologies must not decrease. Furthermore, we must increase our knowledge of infection mechanisms to improve our future defense strategies.

Update on the Role of ß2AR and TRPV1 in Respiratory Diseases.

Respiratory diseases (RDs) constitute a common public health problem both in industrialized and developing countries. The comprehension of the pathophysiological mechanisms underlying these conditions and the development of new therapeutic strategies are critical for improving the quality of life of affected patients. ß2-adrenergic receptor (ß2AR) and transient receptor potential vanilloid 1 (TRPV1) are both involved in physiological responses in the airways. ß2AR is implicated in bronchodilation, mucociliary clearance, and anti-inflammatory effects, while TRPV1 is involved in the mediation of pain and cough reflexes. In RDs, such as respiratory infections, asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, the concentration and expression of these receptors can be altered, leading to significant consequences. In this review, we provided an update on the literature about the role of ß2AR and TRPV1 in these conditions. We reported how the diminished or defective expression of ß2AR during viral infections or prolonged therapy with ß2-agonists can increase the severity of these pathologies and impact the prognosis. Conversely, the role of TRPV1 was pivotal in neuroinflammation, and its modulation could lead to innovative treatment strategies in specific patients. We indicate future perspectives and potential personalized treatments in RDs through a comprehensive analysis of the roles of these receptors in the physiological and pathological mechanisms of these pathologies.

Neuromodulators in Acute and Chronic Cough in Children: An Update from the Literature.

Cough is one of the most common reasons leading to pediatric consultations, negatively impacting the quality of life of patients and caregivers. It is defined as a sudden and forceful expulsion of air from the lungs through the mouth, typically triggered by irritation or the stimulation of sensory nerves in the respiratory tract. This reflex is controlled by a neural pathway that includes sensory receptors, afferent nerves, the brainstem's cough center, efferent nerves, and the muscles involved in coughing. Based on its duration, cough in children may be classified as acute, lasting less than four weeks, and chronic, persisting for more than four weeks. Neuromodulators have shown promise in reducing the frequency and severity of cough by modulating the neural pathways involved in the cough reflex, although they require careful monitoring and patient selection to optimize the outcomes. This review aims to examine the rationale for using neuromodulators in the management of cough in children.

Neurotrophins: Expression of Brain-Lung Axis Development.

Neurotrophins (NTs) are a group of soluble growth factors with analogous structures and functions, identified initially as critical mediators of neuronal survival during development. Recently, the relevance of NTs has been confirmed by emerging clinical data showing that impaired NTs levels and functions are involved in the onset of neurological and pulmonary diseases. The alteration in NTs expression at the central and peripheral nervous system has been linked to neurodevelopmental disorders with an early onset and severe clinical manifestations, often named "synaptopathies" because of structural and functional synaptic plasticity abnormalities. NTs appear to be also involved in the physiology and pathophysiology of several airway diseases, neonatal lung diseases, allergic and inflammatory diseases, lung fibrosis, and even lung cancer. Moreover, they have also been detected in other peripheral tissues, including immune cells, epithelium, smooth muscle, fibroblasts, and vascular endothelium. This review aims to provide a comprehensive description of the NTs as important physiological and pathophysiological players in brain and lung development.

Vascular Endothelial Growth Factor as Molecular Target for Bronchopulmonary Dysplasia Prevention in Very Low Birth Weight Infants.

Bronchopulmonary dysplasia (BPD) still represents an important burden of neonatal care. The definition of the disease is currently undergoing several revisions, and, to date, BPD is actually defined by its treatment rather than diagnostic or clinic criteria. BPD is associated with many prenatal and postnatal risk factors, such as maternal smoking, chorioamnionitis, intrauterine growth restriction (IUGR), patent ductus arteriosus (PDA), parenteral nutrition, sepsis, and mechanical ventilation. Various experimental models have shown how these factors cause distorted alveolar and vascular growth, as well as alterations in the composition and differentiation of the mesenchymal cells of a newborn's lungs, demonstrating a multifactorial pathogenesis of the disease. In addition, inflammation and oxidative stress are the common denominators of the mechanisms that contribute to BPD development. Vascular endothelial growth factor-A (VEGFA) constitutes the most prominent and best studied candidate for vascular development. Animal models have confirmed the important regulatory roles of epithelial-expressed VEGF in lung development and function. This educational review aims to discuss the inflammatory pathways in BPD onset for preterm newborns, focusing on the role of VEGFA and providing a summary of current and emerging evidence.

Type 2 inflammation in cystic fibrosis: New insights.

Recently, type 2 inflammation has been recognized as one of the most critical factors participating in the pathogenesis of cystic fibrosis (CF). On the one hand, type 2 inflammation restores tissue homeostasis and contributes to the resolution of inflammation following an injury. On the other hand, type 2 response-activated immune cells may become dysregulated or chronically activated, causing tissue fibrosis. Among the type 2 cytokine-driven inflammatory pathways, the transforming growth factor ß (TGFß), interleukin (IL)-17, IL-33, and IL-13 have been identified as essential mediators in patients suffering from CF. Given their critical role, we firmly believe that an adequate comprehension of the type 2-mediated pathways can identify attractive targets to decrease pharmacologically the inflammation and fibrosis occurring in the pulmonary tissue of patients suffering from CF.

Pediatric Multisystem Syndrome Associated with SARS-CoV-2 (MIS-C): The Interplay of Oxidative Stress and Inflammation.

Pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (MIS-C) is characterized by persistent fever and evidence of single or multiorgan dysfunction, and laboratory evidence of inflammation, elevated neutrophils, reduced lymphocytes, and low albumin. The pathophysiological mechanisms of MIS-C are still unknown. Proinflammatory mediators, including reactive oxygen species and decreased antioxidant enzymes, seems to play a central role. Virus entry activates NOXs and inhibits Nrf-2 antioxidant response inducing free radicals. The biological functions of nonphagocytic NOXs are still under study and appear to include: defense of epithelia, intracellular signaling mechanisms for growth regulation and cell differentiation, and post-translational modifications of proteins. This educational review has the aim of analyzing the newest evidence on the role of oxidative stress (OS) in MIS-C. Only by relating inflammatory mediators to OS evaluation in children following SARS-CoV-2 infection will it be possible to achieve a better understanding of these mechanisms and to reduce long-term morbidity. The link between inflammation and OS is key to developing effective prevention strategies with antioxidants to protect children.

Cystic Fibrosis and Oxidative Stress: The Role of CFTR.

There is substantial evidence in the literature that patients with cystic fibrosis (CF) have higher oxidative stress than patients with other diseases or healthy subjects. This results in an increase in reactive oxygen species (ROS) and in a deficit of antioxidant molecules and plays a fundamental role in the progression of chronic lung damage. Although it is known that recurrent infection-inflammation cycles in CF patients generate a highly oxidative environment, numerous clinical and preclinical studies suggest that the airways of a patient with CF present an inherently abnormal proinflammatory milieu due to elevated oxidative stress and abnormal lipid metabolism even before they become infected. This could be directly related to cystic fibrosis transmembrane conductance regulator (CFTR) deficiency, which appears to produce a redox imbalance in epithelial cells and extracellular fluids. This review aims to summarize the main mechanism by which CFTR deficiency is intrinsically responsible for the proinflammatory environment that characterizes the lung of a patient with CF.

Chronic cough in childhood: A systematic review for practical guidance by the Italian Society of Pediatric Allergy and Immunology.

The current systematic review presented and discussed the most recent studies on pediatric chronic cough. In addition, the Italian Society of Pediatric Allergy and Immunology elaborated a comprehensive algorithm to guide the primary care approach to a pediatric patient with chronic cough.Several algorithms on chronic cough management have been adopted and validated in clinical practice; however, unlike the latter, we developed an algorithm focused on pediatric age, from birth until adulthood. Based on our findings, children and adolescents with chronic cough without cough pointers can be safely managed, initially using the watchful waiting approach and, successively, starting empirical treatment based on cough characteristics. Unlike other algorithms that suggest laboratory and instrumental investigations as a first step, this review highlighted the importance of a "wait and see" approach, consisting of parental reassurance and close clinical observation, also due to inter-professional collaboration and communication between general practitioners and specialists that guarantee better patient management, appropriate prescription behavior, and improved patient outcome. Moreover, the neonatal screening program provided by the Italian National Health System, which intercepts several diseases precociously, allowing to treat them in a very early stage, helps and supports a "wait and see" approach.Conversely, in the presence of cough pointers or persistence of cough, the patient should be tested and treated by the specialist. Further investigations and treatments will be based on cough etiology, aiming to intercept the underlying disease, prevent potentially irreversible tissue damage, and improve the general health of patients affected by chronic cough, as well as the quality of life of patients and their family.

Acute cough in children and adolescents: A systematic review and a practical algorithm by the Italian Society of Pediatric Allergy and Immunology.

The current systematic review presented and discussed the most recent studies on acute cough in pediatric age. After that, the Italian Society of Pediatric Allergy and Immunology elaborated a comprehensive algorithm to guide the primary care approach to pediatric patients, such as infants, children, and adolescents, with acute cough. An acute cough is usually consequent to upper respiratory tract infections and is self-resolving within a few weeks. However, an acute cough may be bothersome, and therefore remedies are requested, mainly by the parents. An acute cough may significantly affect the quality of life of patients and their family.Several algorithms for the management of acute cough have been adopted and validated in clinical practice; however, unlike the latter, we developed an algorithm focused on pediatric age, and, also, in accordance to the Italian National Health System, which regularly follows the child from birth to all lifelong. Based on our findings, infants from 6 months, children, and adolescents with acute cough without cough pointers can be safely managed using well-known medications, preferably non-sedative agents, such as levodropropizine and/or natural compounds, including honey, glycerol, and herb-derived components.

Nutraceuticals in the Prevention of Viral Infections, including COVID-19, among the Pediatric Population: A Review of the Literature.

In recent years, there has been a growth in scientific interest in nutraceuticals, which are those nutrients in foods that have beneficial effects on health. Nutraceuticals can be extracted, used for food supplements, or added to foods. There has long been interest in the antiviral properties of nutraceuticals, which are especially topical in the context of the ongoing COVID-19 pandemic. Therefore, the purpose of this review is to evaluate the main nutraceuticals to which antiviral roles have been attributed (either by direct action on viruses or by modulating the immune system), with a focus on the pediatric population. Furthermore, the possible applications of these substances against SARS-CoV-2 will be considered.

A Systematic Review of Clinical Practice Guidelines for the Diagnosis and Management of Bronchiolitis.

BACKGROUND: Bronchiolitis is the leading cause of hospital admission for respiratory disease among infants aged <1 year. Clinical practice guidelines can benefit patients by reducing the performance of unnecessary tests, hospital admissions, and treatment with lack of a supportive evidence base. This review aimed to identify current clinical practice guidelines worldwide, appraise their methodological quality, and discuss variability across guidelines for the diagnosis and management of bronchiolitis. METHODS: A systematic literature review of electronic databases EMBASE, Global Health, and Medline was performed. Manual searches of the gray literature, national pediatric society websites, and guideline-focused databases were performed, and select international experts were contacted to identify additional guidelines. The Appraisal of Guidelines for Research and Evaluation assessment tool was used by 2 independent reviewers to appraise each guideline. RESULTS: Thirty-two clinical practice guidelines met the selection criteria. Quality assessment revealed significant shortcomings in a number of guidelines, including lack of systematic processes in formulating guidelines, failure to state conflicts of interest, and lack of consultation with families of affected children. There was widespread agreement about a number of aspects, such as avoidance of the use of unnecessary diagnostic tests, risk factors for severe disease, indicators for hospital admission, discharge criteria, and nosocomial infection control. However, there was variability, even within areas of consensus, over specific recommendations, such as variable thresholds for oxygen therapy. Guidelines showed significant variability in recommendations for the pharmacological management of bronchiolitis, with conflicting recommendations over whether use of nebulized epinephrine, hypertonic saline, or bronchodilators should be routinely trialled. CONCLUSIONS: Future guidelines should aim to be compliant with international standards for clinical guidelines to improve their quality and clarity and to promote their adoption into practice. Variable recommendations between guidelines may reflect the evolving evidence base for bronchiolitis management, and platforms should be created to understand this variability and promote evidence-based recommendations.

Type-2 inflammatory mediators as targets for precision medicine in children.

The prevalence, heterogeneity, and severity of type 2 inflammatory diseases, including asthma and atopic dermatitis, continue to rise, especially in children and adolescents. Type 2 inflammation is mediated by both innate and adaptive immune cells and sustained by a specific subset of cytokines, such as interleukin (IL)-4, IL-5,IL-13, and IgE. IL-4 and IL-13 are considered signature type 2 cytokines, as they both have a pivotal role in many of the pathobiologic changes featured in asthma and atopic dermatitis. Several biologics targeting IL-4, IL-5, and IL-13, as well as IgE, have been proposed to treat severe allergic disease in the pediatric population with promising results. A better definition of type 2 inflammatory pathways is essential to implement targeted therapeutic strategies.

Acute urticaria in the infant.

Urticaria is a mast cell-driven disease presenting with wheals, angioedema, or both. Acute urticaria (AU) lasts < 6 weeks. AU is a not common condition in newborns and infants since they are showing an immune system functionally insufficient. In newborns and infants, AU is typically generalized and featured by large, annular, or geographic plaques, often slightly raised. The clinical features of the disease depend on the peculiar structure of neonatal and infant skin. A careful morphological examination of the lesions is essential to differentiate AU from other skin eruptions that may have overlapping features and to treat it adequately. The second-generation antihistamines are the first-line treatment of AU; however, only antihistamines with proven efficacy and safety should be used in newborns and infants. Corticosteroids may be added in severe cases.

Severe asthma in children: Current goals and unmet needs.

Severe asthma in children is considered a complex and heterogeneous disease. A multidisciplinary assessment is required to correctly identify and manage these children because they potentially need close monitoring and additional treatment with advanced targeted therapies. Recent research efforts focused on the identification of epidemiologic, clinical, and functional characteristics of the disease in the pediatric age. Novel findings on the molecular mechanisms underlying severe asthma have led to the recognition of different endotypes and related biomarkers able to predict the response to advanced biologic therapies. Progress in our knowledge of severe asthma has occurred with the introduction of biologic therapies. Future goals in asthma care include the identification of the links between phenotypes and endotypes, as well as the identification of novel predictive biomarkers. They will help to select candidates for innovative biologic therapies and ultimately improve outcomes in children with severe asthma.

Gastrointestinal involvement in children with SARS-COV-2 infection: An overview for the pediatrician.

Gastrointestinal symptoms are common findings in children with SARS-CoV-2 infection. Diarrhea and vomiting have been reported in about 8%-9% of cases, reaching more than 20% in some studies. Children with gastrointestinal involvement appear to be younger than those without, but the severity of the disease seems to be similar between the two groups of subjects. Fecal shedding in children has been reported in 20%-30% of children and has been observed in both those with and those without overt gastrointestinal involvement. Moreover, prolonged fecal elimination, lasting several days after negativization of real-time polymerase chain reaction assay on respiratory swabs, has been reported with variable frequency in children with SARS-CoV-2 infection. These observations raise the question regarding the possibility of oral-fecal transmission and the possible role of children in spreading the infection, particularly when they appear asymptomatic or with gastrointestinal symptoms but with no respiratory involvement, as well as during their convalescent phase.

Antihistamines: ABC for the pediatricians.

Antihistamines are currently one of the most commonly administered drugs in children. They are used to treat symptoms that depend on histamine release, namely allergic diseases, such as rhinitis, asthma, urticaria, and anaphylaxis. It is possible to distinguish first- and second-generation antihistamines. Pharmacological effects and therapeutic indications are similar, but second-generation antihistamines have fewer adverse effects because they are more selective for peripheral H1 receptors. Although they have been on the market for several years, there are still many adverse effects linked to the antihistamine safety profile, especially in the first years of life. Thus, many antihistamines are prescribed off-label, especially in children younger than 2 years of age, which is the age-group where most of the data on drug safety are lacking and many antihistamines are not recommended. This article aims to provide a practical update on the use of antihistamines in children.

Allergic bronchopulmonary aspergillosis in children.

Allergic bronchopulmonary aspergillosis (ABPA) is a pulmonary disease caused by Aspergillus induced hypersensitivity that occurs in immunocompetent but susceptible patients with asthma and/or cystic fibrosis (CF). In children, ABPA remains mostly undiagnosed resulting in one of the most common causes of poorly controlled asthma and highly significant morbidity in children with CF. Currently, no specific diagnostic criteria of ABPA for children are available. Corticosteroids and itraconazole are the mainstays of therapy although there is a lack of randomized clinical trials regarding their usefulness for ABPA in children. Several monoclonal antibodies, such as omalizumab and mepolizumab, may be potential therapies for refractory ABPA in pediatric patients; however, further data are required to clarify the optimal dose and duration of therapy as a routine treatment approach.