Risk of Prevalent Asthma among Children Affected by Inflammatory Bowel Disease: A Population-Based Birth Cohort Study

The re-emerging role of linoleic acid in paediatric asthma

Asthma is the most common chronic disease within the paediatric population. Although it is multifactorial, its onset may be linked to early-life exposures with subsequent impact on immune system development. Microbial and dietary metabolic products have been implicated in the development and exacerbation of paediatric asthma. Linoleic acid is the most common omega-6 polyunsaturated fatty acid in the Western diet. In this review, we summarise the literature regarding the involvement of linoleic acid in the development of and its impact on existing paediatric asthma. First, we summarise the existing knowledge surrounding the relationship between human microbial metabolism and allergic diseases in children. Next, we examine cellular or animal model-based mechanistic studies that investigated the impact of dietary- and microbial-derived linoleic acid metabolites on asthma. Finally, we review the literature investigating the impact of linoleic acid metabolites on the development and exacerbation of childhood asthma. While there is conflicting evidence, there is growing support for a role of linoleic acid in the onset and pathophysiology of asthma. We recommend that additional cellular, animal, and longitudinal studies are performed that target linoleic acid and its metabolites.

Allergy and autoimmunity in children: non-mutually exclusive diseases. A narrative review

In last decades a simultaneous increase in the prevalence of atopic and autoimmune disorders in pediatric population has been observed. Despite the Th1-Th2 paradigm, supporting the polarization of the immune system with Th1 response involved in autoimmune diseases and Th2 response leading to hypersensitivity reactions, recent evidence suggests a possible coexistence of common pathogenic pathways as result of shared immune dysregulation. Similar genes and other mechanisms such as epithelial barrier damage, gut microbiota dysbiosis and reduced number of T regs and IL-10 contribute to the onset of allergy and autoimmunity. IgA deficiency is also hypothesized to be the crosslink between celiac disease and allergy by lowering gut mucous membrane protection from antigens and allergens. The present narrative review aims to give an overview of the co-occurrence of allergic and autoimmune disorders (celiac disease, inflammatory bowel diseases, type 1 diabetes mellitus, thyroid disease, juvenile idiopathic arthritis) in pediatric population, based on the available evidence. We also highlighted the common pathogenic pathways that may underpin both. Our findings confirm that allergic and autoimmune diseases are commonly associated, and clinicians should therefore be aware of the possible coexistence of these conditions in order to ameliorate disease management and patient care. Particular attention should be paid to the association between atopic dermatitis or asthma and celiac disease or type 1 diabetes and vice versa, for therapeutic interventions. Further studies are needed to better clarify mechanisms involved in the pathogenesis and eventually identify new therapeutic strategies.

Navigating the landscape of Rho GTPase signalling system in autoimmunity: A bibliometric analysis spanning over three decades (1990 to 2023)

Ras-homologous (Rho) guanosine triphosphatases (GTPases) are considered a central player in regulating various biological processes, extending to immune regulation. Perturbations in Rho GTPase signalling have been implicated in immune-related dysregulation, contributing to the development of autoimmunity. This study presents a scientometric analysis exploring the interlink between the Rho GTPase signalling system and autoimmunity, while also delving into the trends of past studies. A total of 967 relevant publications from 1990 to 2023 were retrieved from the Web of Science Core Collection database after throrough manual filtering of irrelevant articles. The findings show an upward trajectory in publications related to this field since 2006. Over the past three decades, the United States of America (41.68%) emerged as the primary contributor in advancing our understanding of the association between the Rho GTPase signalling system and autoimmunity. Research in autoimmunity has mainly centered around therapeutic interventions, with an emphasis on studying leukocyte (macrophage) and endothelial remodelling. Interestingly, within the domains of multiple sclerosis and rheumatoid arthritis, the current focus has been directed towards comprehending the role of RhoA, Rac1, and Cdc42. Notably, certain subfamilies of Rho (such as RhoB and RhoC), Rac (including Rac2 and RhoG), Cdc42 (specifically RhoJ), and other atypical Rho GTPases (like RhoE and RhoH) consistently demonstrating compelling link with autoimmunity, but still warrants emphasis in the future study. Hence, strategic manipulation of the Rho signalling system holds immense promise as a pivotal approach to addressing the global challenge of autoimmunity.

Alteration of Gut Immunity and Microbiome in Mixed Granulocytic Asthma

Growing evidence suggests that there is an essential link between the gut and lungs. Asthma is a common chronic inflammatory disease and is considered a heterogeneous disease. While it has been documented that eosinophilic asthma affects gut immunity and the microbiome, the effect of other types of asthma on the gut environment has not been examined. In this study, we utilized an OVA/poly I:C-induced mixed granulocytic asthma model and found increased Tregs without significant changes in other inflammatory cells in the colon. Interestingly, an altered gut microbiome has been observed in a mixed granulocytic asthma model. We observed an increase in the relative abundance of the Faecalibaculum genus and Erysipelotrichaceae family, with a concomitant decrease in the relative abundance of the genera Candidatus arthromitus and Streptococcus. The altered gut microbiome leads to changes in the abundance of genes associated with microbial metabolism, such as glycolysis. We found that mixed granulocytic asthma mainly affects the gut microbial composition and metabolism, which may have important implications in the severity and development of asthma and gut immune homeostasis. This suggests that altered gut microbial metabolism may be a potential therapeutic target for patients with mixed granulocytic asthma.

Geosocial Features and Loss of Biodiversity Underlie Variable Rates of Inflammatory Bowel Disease in a Large Developing Country: A Population-Based Study

BACKGROUND

The epidemiology of inflammatory bowel disease (IBD) in developing countries may uncover etiopathogenic factors. We investigated IBD prevalence in Brazil by investigating its geographic, spatial, and temporal distribution, and attempted to identify factors associated with its recent increase.

METHODS

A drug prescription database was queried longitudinally to identify patients and verify population distribution and density, race, urbanicity, sanitation, and Human Development Index. Prevalence was calculated using the number of IBD patients and the population estimated during the same decade. Data were matched to indices using linear regression analyses.

RESULTS

We identified 162 894 IBD patients, 59% with ulcerative colitis (UC) and 41% with Crohn's disease (CD). The overall prevalence of IBD was 80 per 100 000, with 46 per 100 000 for UC and 36 per 100 000 for CD. Estimated rates adjusted to total population showed that IBD more than triplicated from 2008 to 2017. The distribution of IBD demonstrated a South-to-North gradient that generally followed population apportionment. However, marked regional differences and disease clusters were identified that did not fit with conventionally accepted IBD epidemiological associations, revealing that the rise of IBD was variable. In some areas, loss of biodiversity was associated with high IBD prevalence.

CONCLUSIONS

When distribution is considered in the context of IBD prevalence, marked regional differences become evident. Despite a background of Westernization, hotspots of IBD are recognized that are not explained by population density, urbanicity, sanitation, or other indices but apparently are explained by biodiversity loss. Thus, the rise of IBD in developing countries is not uniform, but rather is one that varies depending on yet unexplored factors like geoecological conditions.

Bypassing the Gut-Lung Axis via Microbial Metabolites: Implications for Chronic Respiratory Diseases

The gut microbiome engages in constant interactions with the immune system, laying down the fundamentals of what we perceive as health or disease. The gut microbiota acts locally in the intestines and distally in other organs, such as the lungs. This influence (termed “the gut–lung axis”) constitutes the basis for harnessing the microbiome to prevent or treat chronic respiratory diseases. Within this context, two approaches gained the most attention: the diet interventions (which shape the microbiome) and the probiotics (which exert beneficial effects directly on the host). Microbial products, which constitute a means of communication along the gut–lung axis, are only now emerging as a new class of potential therapeutics. Here, we provide a comprehensive overview of microbial products active in the airways, describe the immunological mechanisms they trigger, and discuss their clinical advantages and pitfalls.

Inflammatory bowel disease and the lung in paediatric patients

The prevalence of inflammatory bowel disease (IBD) has increased over the past 20 years. Pulmonary involvement in paediatric IBD is rare but may be missed since the spectrum of symptoms is broad and mimics other diseases. The most important differential diagnoses of pulmonary manifestations of IBD are infections and therapy-related side-effects. There is no gold standard to diagnose respiratory manifestations in children with IBD. Diagnostic tests should be chosen according to history and clinical presentation. Treatment of respiratory manifestations of IBD includes inhaled or oral corticosteroids and initiation or step-up of immunomodulatory IBD therapies.

Pulmonary involvement in paediatric IBD is rare but may be underdiagnosed. The spectrum of symptoms is broad and mimics other diseases. The differentiation between IBD-related and drug-induced pulmonary manifestation can be challenging.https://bit.ly/3uZBvpA

Population-Based Birth Cohort Studies in Epidemiology

Birth cohort studies are the most appropriate type of design to determine the causal relationship between potential risk factors during the prenatal or postnatal period and the health status of the newborn up to childhood and potentially adulthood. To date, there has been a growth in interest regarding observational population-based studies which are performed to provide answers to specific research questions for defined populations, for instance, assessing the exposure to environmental pollutants or drugs on the risk of developing a disease. Birth cohorts based on the recruitment and active follow-up of mothers and children allow the collection of biological material, and specific clinical and genetic information. However, they require a considerable amount of time and resources and, besides being usually of limited size, they are exposed to the risk of the loss of subjects to follow-up, with decreased statistical power and possible selection bias. For these reasons, linking the medical birth register with administrative health records for mothers and babies is increasingly being used in countries with a universal healthcare system, allowing researchers to identify large and unselected populations from birth, and to reconstruct relevant traits and care pathways of mothers and newborns. This Special Issue of the International Journal of Environmental Research and Public Health focuses on the current state of knowledge on perinatal and postnatal exposures and adverse pregnancy, maternal, fetal and neonatal outcomes through population-based birth cohort studies, with a specific focus on real-word data. The 12 accepted articles covered a wide range of themes that can be addressed specifically through birth cohort study design; however, only three were based on real word data with record-linkage to health administrative databases. In particular, two papers have addressed the topic of socioeconomic status considering several indicators both at the individual and contextual level. Two papers focused on inflammatory bowel diseases, both as an outcome of perinatal and antibiotic exposure in early life and as a condition associated with asthma, among children identified in a birth cohort based on a Regional Medical Birth Register. Three articles focused on medication use during pregnancy and its impact on maternal and fetal health. The effect of exposure to prenatal environmental risk factors on perinatal and childhood outcomes has been considered in two papers. Two papers analyzed ad hoc nationwide prospective birth cohorts set in Japan and UK. Finally, we included a systematic review with meta-analysis to evaluate the relation between growth restriction at birth and congenital heart defects. We think that this Special Issue may contribute to enriching the discussion of future challenges, opportunities, strengths and limitations for all research topics that can be investigated using a population-based birth cohort study design.