Biodiversity intervention enhances immune regulation and health-associated commensal microbiota among daycare children

The role of the early-life gut microbiome in childhood asthma

Asthma is a chronic disease affecting millions of children worldwide, and in severe cases requires hospitalization. The etiology of asthma is multifactorial, caused by both genetic and environmental factors. In recent years, the role of the early-life gut microbiome in relation to asthma has become apparent, supported by an increasing number of population studies, in vivo research, and intervention trials. Numerous early-life factors, which for decades have been associated with the risk of developing childhood asthma, are now being linked to the disease through alterations of the gut microbiome. These factors include cesarean birth, antibiotic use, breastfeeding, and having siblings or pets, among others. Association studies have highlighted several specific microbes that are altered in children developing asthma, but these can vary between studies and disease phenotype. This demonstrates the importance of the gut microbial ecosystem in asthma, and the necessity of well-designed studies to validate the underlying mechanisms and guide future clinical applications. In this review, we examine the current literature on the role of the gut microbiome in childhood asthma and identify research gaps to allow for future microbial-focused therapeutic applications in asthma.

The case for microbiome stewardship: what it is and how to get there

Microbiomes are essential for human, animal, plant, and ecosystem health. Despite widespread recognition of the importance of microbiomes, there is little attention paid to monitoring and safeguarding microbial ecologies on policy levels. We observe that microbiomes are deteriorating owing to practices at societal levels such as pesticide use in agriculture, air and water pollution, and overuse of antibiotics. Potential policy on these issues would cross multiple domains such as public health, environmental protection, and agriculture. We propose microbiome stewardship as a foundational concept that can act across policy domains to facilitate healthy microbiomes for human and ecosystem health. We examine challenges to be addressed and steps to take toward developing meaningful microbiome stewardship.

Intervention effects of greenspace exposure on human microbiota: A randomized controlled trial in Chinese young adults

Enriching human microbiota has been proposed as a mechanism by which greenspace exposure improves human health. The existing evidence is scarce with few studies able to evaluate causality. We conducted a randomized controlled trial of 30 healthy undergraduate students to explore the intervention effects of greenspace on human gut and oral microbiota alpha-diversity, composition, differential genera and functional pathways. The study participants were divided into three groups, including outdoor greenspace (GS) group, outdoor non-greenspace (NGS) group, and indoor group, who visited a park, an open space without vegetation, and a classroom, respectively, for two hours per day over seven days. Differences in microbial alpha-diversity and composition across various groups were tested using Wilcoxon test and permutational multivariate analysis of variance, respectively. Linear discriminant analysis effect size analysis was performed to test differences in genera and functional pathways. Greenspace intervention significantly increased gut microbiota alpha-diversity, especially the observed Amplicon Sequence variant indexes and the Faith indexes (both p < 0.05). In addition, the intervention substantially changed the composition of gut microbiota, of which the relative abundances of potentially beneficial bacteria increased. Further, the greenspace intervention affected several functional pathways of gut microbiota, including "substance dependence", "specific types of cancer", and "viral infectious diseases". However, we did not find any significant effect of greenspace intervention on oral microbiota. Our results suggest that greenspace intervention diversifies the gut microbiota and alters its composition. These findings could help to reinforce the potential of increasing people's access to greenspace as a public health intervention.

Domestic gardens and morbidity: Associations between private green space and diagnosed health conditions in the Netherlands

BACKGROUND

Previous studies observed predominantly positive associations between the amount of nearby green space and a variety of health outcomes. Although nearness is assumed to be an important aspect of this association, the presence of own private green space is rarely studied. We investigated cross-sectional associations between the amount of domestic garden greenery and the prevalence of 21 health conditions.

METHODS

Electronic health records of general practitioners, providing data on health conditions of individuals and where they lived for the year 2018, were linked with data from the same year on garden presence and size derived from the Netherlands' Cadastre, Land registry and Mapping Agency. Amount of garden greenery was assessed with high resolution aerial photographs. Data were available for about 800,000 persons from 294 practices. We performed multi-level logistic regression analyses with practice as second level, adjusting for multiple covariates, including socioeconomic status at individual and neighbourhood level.

FINDINGS

Prevalence of 16 of the 21 health conditions was lower for at least the highest classes of garden greenery. The inverse association was strongest for intestinal tract infections, with an over 20 % lower prevalence if the garden contained at least 50 m2 greenery versus no garden. Including the overall amount of greenery within 125 m of the home in the analyses did not attenuate the results. Sex was an important moderator, with many associations being stronger for women.

CONCLUSIONS

Own private green space is inversely associated with the prevalence of many health conditions, more so than other nearby green space. Responsible pathways are unclear. Further research is needed to confirm these findings and to identify the pathways underlying the cross-sectional associations. Information on pathways may also offer clues on how to compensate for the absence of a domestic garden, which is likely to become more common due to urban densification.

Exposure to green space is associated with higher skin microbiota species richness in children

Skin is the exterior interface of the human body with the environment and harbors millions of microorganisms crucial for skin health. Associations between early-life green space exposure and the skin microbiome of children remain unstudied. Skin swabs were collected from 402 children (4-12 years old) enrolled in the ENVIRONAGE birth cohort. Skin alpha diversity indices and the relative abundance at family and species levels were determined using 16S rRNA gene HiFi amplicon sequencing. Total green, high-growing green, and low-growing green were estimated in several radii around their current residential and school address based on high-resolution land cover data. Multiple linear regression models between green-space indices and skin microbiome alpha diversity indices were adjusted for sex, age, frequency of soap use, maternal education, season of skin swab collection, sequencing batch, and storage duration of the skin swab. As interaction terms between green-space indices and season were borderline statistically significant, we also ran the linear regression models stratified by season. Last, we performed a differential relative abundance analysis, accounting for the covariables above. Total green and high-growing green in multiple radii (from 100 to 500 m) were positively associated with observed richness (regression coefficients ranging from 10.06 to 15.31 [P-value ranging from 0.03 to 0.12] per interquartile range increase in green). The associations were only statistically significant when skin swabs were collected in the warm season. The relative abundance of the bacterial families Xanthomonadaceae, Intrasporangiaceae, Pseudomonadaceae, and Caulobacteraceae was statistically significantly positively associated with total and high-growing green within 300 m. Our findings suggest an influential role of early-life green space exposure on skin microbiome composition. Additional research is needed to investigate whether the observed positive relationship between green space and skin bacterial richness has implications for human health.

Pilot Testing an Ecotherapy Program for Adolescence: Initial Findings and Methodological Reflections

Children and young people's mental health and well-being has seen a dramatic decline. In the UK, this has been exacerbated by service retrenchment associated with austerity, with evidence of increasing health inequalities. Service innovation that is grounded in practice, has ongoing learning, and is co-designed with children and young people is required now. This can provide creative solutions within the local context and contribute to the fledgling evidence base that explores complex mechanisms of impact. This methodological reflection describes a co-design process of a bespoke, group-based ecotherapy programme: from early piloting using appreciative enquiry before COVID-19 by the mental health, public health, and Street Services team in the port city of Plymouth, to further developing an evaluation framework through an innovative, matched-funded academia-practice partnership. The findings showcase the benefits of a systems-based approach to public, multi-agency and academic collaboration, facilitated by peer and practitioner researchers and embedded researchers-in-residence. They highlight the need to consider nuances of specific (connecting with self, others, animals, nature) and non-specific active ingredients of the emerging and constantly adapting service (therapeutic relationship with practitioners/carers; nature as therapist, and group dynamics), as well as the value of pragmatic and participatory evaluation methods (distance-travelled, goal-based measures; and ethnographic, qualitative observation), to provide rapid, continuous, and real-time learning and improvement.

How the Built Environment Shapes Children's Microbiome: A Systematic Review

This systematic review aims to synthesize key empirical findings to understand how various elements of the built environment influence the microbiome concerning children's health and well-being. A comprehensive literature search was conducted across multiple databases, focusing on studies that examined the relationship between built environment factors and the microbiome aspects of childhood. A total of 42 studies were included in the final systematic review. We analyzed these studies from a range of different lenses, starting with basic research questions and variables to types of built environments, age groups of children, sampling strategy, bioinformatics, and the biological methods utilized. This review highlights a growing emphasis on children's exposure to nature within built environments and its potential to beneficially alter the microbiome, with 38% of studies addressing this link. It also identifies a significant research gap in connecting built environment design features (landscape and/or architectural) to microbiome outcomes and associated health, behavioral, and mental health impacts on children. The findings indicate that interventions aimed at improving the built environment quality via design could foster healthier microbiomes in children's environments. This review underscores the need for interdisciplinary research and policy initiatives that integrate microbiome science with built environment design to promote children's health and well-being.

Microbial communities on dry natural rocks are richer and less stressed than those on man-made playgrounds

In modern urbanized societies, the incidence of major immune-mediated diseases is several times higher than before World War II. A potential explanation is that these diseases are triggered by limited possibilities to be exposed to rich environmental microbiota. This requires that the urban environment hosts less and poorer microbiota than the natural environment. The current study was designed to test the assumption that urban man-made environments host less and poorer environmental microbiota, compared to natural habitats. We selected two types of dry environments, natural rocks and playground rubber mats, both of which were used daily and extensively by children. In quantitative PCR and next-generation sequencing, bacterial abundance and richness were higher on the natural rocks than the rubber mats. Altogether, 67 amplicon sequence variants (ASVs) belonging mostly to Actinobacteria and Proteobacteria were indicative of rock microbiota, while three ASVs were indicative of rubber mats. Interestingly, bacteria formed more complex networks on rubber mats than natural rocks. Based on the literature, this indicates that the studied artificial dry environment is more challenging and stressful for bacterial communities than dry natural rocks. The results support the hypothesis that urban man-made environments host poor microbial communities, which is in accordance with the biodiversity hypothesis of immune-mediated diseases.IMPORTANCEThe current study provides new evidence that artificial urban play environments host poor microbial communities and provide a stressful environment for microbes, as compared to dry natural rocks. Through this, the current study underlines the need to enhance microbial diversity in urban areas, especially in outdoor play environments, which have a crucial role in providing essential microbial exposure for the development of children's immune system. This research can potentially offer guidance for urban planning and public health strategies that support planetary health.

A randomized controlled trial of environmental richness on gastrointestinal symptoms, salivary cortisol, and gut microbiota in early childhood

Gastrointestinal (GI) symptoms are common and can affect children's social lives. This study investigated the effects of exposure to a rich natural environment on GI symptoms, salivary cortisol levels, salivary amylase levels, and the gut microbiota in young children. Children aged 5-6 years from four kindergartens in Japan were randomly assigned to two groups: a nature childcare group and a regular childcare group. The children were exposed to their respective conditions once weekly for one month. Before and after the intervention, GI symptoms were detected using the Children's Somatization Inventory to calculate a 'GI score' and categorize participants into GI and control groups (primary outcome measure). Fecal examinations were performed for gut microbiota using 16 S-rRNA analysis, salivary cortisol and amylase levels were quantified, and the Child Behavior Checklist was administered. The two groups had similar GI symptoms, salivary cortisol and amylase levels, and behavioral characteristics. Following the intervention, significant differences in the GI score, abdominal pain, constipation, Shannon index value, and salivary cortisol and amylase levels (p < 0.05) were observed between the two childcare groups. Spending free and abundant time in nature during early childhood could help maintain digestive system homeostasis, increase gut microbiota diversity, and reduce cortisol levels.

Exploring the Utility of the Gut Microbiome as a Longitudinal Health Monitoring Tool in Sanctuary Chimpanzees (Pan troglodytes)

The primary goal of captive primate management is to ensure optimal health and welfare of the animals in our care. Given that the gut microbiome interacts closely with host metabolism, immunity, and even cognition, it represents a potentially powerful tool for identifying subtle changes in health status across a range of body systems simultaneously. However, thus far, it has not been widely tested or implemented as a monitoring tool. In this study, we used longitudinal microbiome sampling of newly arrived chimpanzees at Chimp Haven to explore the feasibility of using the gut microbiome as a health and welfare biomarker in a sanctuary environment. We also tested the hypothesis that a transition to a new living environment, and integration into new social groupings, would result in temporal changes in chimpanzee gut microbiome composition. The collection of longitudinal microbiome data at Chimp Haven was feasible, and it revealed temporal shifts that were unique to each individual and, in some cases, correlated to other known impacts on health and behavior. We found limited evidence for microbial change over time after arrival at Chimp Haven that was consistent across individuals. In contrast, social group and enclosure, and to a lesser extent, age and sex, were associated with differences in gut microbiome composition. Microbiome composition was also associated with overall health status categories. However, many of the effects we detected were most apparent when using longitudinal data, as opposed to single time point samples. Additionally, we found important effects of technical factors, specifically outdoor temperature and time to collection, on our data. Overall, we demonstrate that the gut microbiome has the potential to be effectively deployed as a tool for health and environmental monitoring in a population of sanctuary chimpanzees, but the design must be carefully considered. We encourage other institutions to apply these approaches and integrate health and physiology data to build on the utility of gut microbiome analysis for ensuring the welfare of captive primates in a range of contexts.

Skin Microbiota and Pathological Scars: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

Pathological scars (PSs), resulting from abnormal skin repair, chronic inflammation, and fibrosis, affect millions of people. Previous studies have demonstrated that skin microbiota (SM) plays a role in cutaneous inflammation and healing, but the interplay between PSs and SM remains unclear yet.

OBJECTIVE

To investigate the causal associations between SM and two specific PSs: hypertrophic scars (HSs) and keloids.

METHODS

A bidirectional two-sample mendelian randomization (MR) analysis using genetic data for SM, HS, and keloids was conducted. The random-effects inverse variance weighted (IVW) method was used as the primary approach, along with multiple MR methods. False discovery rate (FDR) correction was employed to address multiple testing.

RESULTS

In forward analysis, the family Moraxellaceae and order Pseudomonadales exhibited the same significant protective effects on keloids (odds ratio [OR]: 0.849, 95% confidence interval [CI]: 0.770-0.935, q2 = 0.03626). The class Betaproteobacteria (OR: 0.938, 95% CI: 0.894-0.985, q1 = 0.01965) and genus Bacteroides (OR: 0.928, 95% CI: 0.884-0.973, q1 = 0.00889) each demonstrated a suggestive protective effect on HSs and keloids, respectively. Some limited evidence suggested that order Actinomycetales contributes to an increased risk of keloids. In reverse analysis, keloids were found to have negative effects on the class Gammaproteobacteria with limited evidence. There was no detectable evidence of horizontal pleiotropy or heterogeneity.

CONCLUSION

This study provided evidence for the causalities between SM and PSs, which laid foundation for furthering clinical practice and research of microorganism-skin interaction.

Urban Greening and Pollen Allergy: Balancing Health and Environmental Sustainability

Urban living requires a careful balance between human health and environmental sustainability when selecting urban vegetation. Public gardens and green roofs offer significant environmental benefits, including air filtration, exposure to health-associated microbiota, and mitigation of the urban heat island effect. However, prioritizing allergy-friendly species is crucial to prevent the exacerbation of pollen allergies. This review highlights 3 primary criteria for selecting vegetation that supports these ecosystem services while minimizing allergy risks. First, reducing the use of many wind-pollinated plants, such as birch trees and grasses, is crucial due to their high pollen production and cross-reactivity with other species, which can exacerbate allergies. In contrast, insect-pollinated plants are generally safer for allergy sufferers. Secondly, cultivating multispecies plant communities with minimal maintenance supports habitats for microbiota and invertebrates, further providing ecosystem services. Lastly, balancing plant gender ratios in urban spaces can help control pollen levels. Together these criteria provide a framework for urban planners to create green spaces that are both environmentally beneficial and allergy friendly. Although this review focuses on European data, the principles discussed have global relevance, reinforcing the need to integrate environmental sustainability with public health considerations in urban planning. Future studies should also investigate the health impacts of plant volatile emissions, explore heat-resistant plant varieties, and assess the ecological risks of invasive species to support sustainable, allergy-friendly urban environments.

Results from the PROmoting Early Childhood Outside cluster randomized trial evaluating an outdoor play intervention in early childhood education centres

Participation in outdoor play is beneficial for the health, well-being, and development of children. Early childhood education centers (ECECs) can provide equitable access to outdoor play. The PROmoting Early Childhood Outside (PRO-ECO) study is a pilot randomized trial that evaluates the PRO-ECO intervention on children's outdoor play participation. The PRO-ECO intervention included four components: ECEC outdoor play policy; educator training; ECEC outdoor space modification; and parent engagement. This study included eight ECECs delivering licensed care to children (n = 217) aged 2.5 to 6 years in Greater Vancouver, British Columbia, Canada. Using a wait-list control cluster randomized trial design, ECECs were randomly allocated to either the intervention arm (n = 4) or the wait-list control arm (n = 4). Change in the proportion and diversity of observed outdoor play behaviour during scheduled outdoor time was measured. Outcome data were collected at baseline, 6-month follow-up, and 12-month follow-up. The intervention effect on children's outdoor play participation was examined using logistic regression mixed effect models. Controlling for gender, weather and temperature, there were no changes in children's outdoor play participation following implementation of the PRO-ECO intervention in the between-group analysis. Within-group comparisons also revealed no change in play participation following the PRO-ECO intervention, however, the intervention group showed a positive effect (OR = 1.28, 95% CI = 0.97, 1.70) in play participation 6 months after implementation of the intervention. The findings indicate that further analyses on child- and ECEC-level outcomes collected as part of the PRO-ECO study, including the diversity of children's play, is required to effectively assess the impact of this intervention.

Residential Area Characteristics Are Associated With Asthma Burden in Children

BACKGROUND

Wheezing illnesses, especially those triggered by rhinovirus infection, cause a major disease burden, and they often precede asthma. Environmental exposures are known to affect recurrence of wheezing. We investigated the relations of population density, greenness (forested areas), and socioeconomic factors of the living surroundings to the burden of asthma in children with prior bronchiolitis.

METHODS

Three hundred and ninety-four children, aged 0-24 months, with doctor-diagnosed bronchiolitis were enrolled in the MARC-30 Finland study. We assessed the children's early-life exposures to greenness and socioeconomic factors using time-series of Corine Land Cover data and Statistics Finland's grid data. We compared the living surroundings data to the prescription drug purchases and special asthma reimbursement benefits until the age 8 years; asthma data were from the Social Insurance Institution of Finland.

RESULTS

Children living in sparsely populated areas had lighter asthma disease burden than children living in densely populated ones, with burden measured in median bronchodilator (50DDD [defined daily dose] vs. 104DDD, p = 0.02) and inhaled corticosteroid (0DDD vs. 123DDD, p = 0.04) purchases. In the subgroup of children with rhinovirus-induced bronchiolitis, children living in more forested areas developed asthma 10 months later than those with less forested areas (p = 0.04). Neighborhood socioeconomic characteristics were not associated with differences in asthma burden.

CONCLUSIONS

Sparsely populated areas and forested environments seem to have a beneficial association with children's respiratory health. These findings warrant further studies on the protective health effects of greenness and the type of biodiversity around homes.

Impact of urban biodiversity and climate change on children's health and well being

In recent decades, biodiversity loss has greatly impacted planetary and human health. Children are at additional risk of adverse effects due to unique biological, developmental, and behavioral factors, as well as their longer exposure to an altered planet as a function of their young age. These effects are heightened for children living in vulnerable socioeconomic conditions. Here, we review the role of biodiversity loss on accelerating the consequences of climate change from the perspective of pediatric health. With the loss of biodiversity's protective role against the consequences of climate change, the adverse effects of the changing planet are impacting pediatric health. For example, trees provide shelter against heat waves, unsealed soil and wetlands mitigate flooding, and rewilded green space hosts high microbial richness and consequently supports immune and mental health. The effects of the loss of biodiversity may impact the discovery and development of novel pharmaceuticals and thus the future of children's medicine as a whole. We also highlight areas for further study and detail efforts that have been made to restore biodiversity, with the aim to improve the current and future health of local pediatric populations. IMPACT: Loss of biodiversity is occurring at a rapid pace affecting the health of the planet and disproportionately pediatric health. This paper describes the role of biodiversity loss in accelerating the impact of climate change on children's health, and highlights particularly vulnerable populations. This paper details steps that can be taken to maintain and restore biodiversity at the local and global levels to protect these populations and pediatric health in general.

Neighborhood plant community, airborne microbiota transferred indoors and prevalence of respiratory diseases are interrelated: A cross-sectional study

Airborne microbiota transferred indoors (AMTI) is linked to human respiratory health. Yet, the factors influencing these microorganisms and their connections to the prevalence of respiratory diseases (RDs) remain unclear. In this study, we examined plant communities and AMTI using VenTube, next-generation sequencing and quantitative polymerase chain reaction (qPCR) in 72 Shanghai neighborhoods in warm and cold seasons, respectively. To determine the prevalence of RDs, we collected 1026 questionnaires, enlisting 30 ± 5 volunteers aged 40-80, residing in the area for more than a decade, with an equal gender balance. Our results demonstrated that the AMTI communities were less diverse in the cold season than in the warm season, which is in agreement with the changes of garden plant diversity between seasons. Along the reduction of AMTI diversity, greater relative abundances of RDs-associated microbes (e.g., Pseudomonas and Streptococcus) was transferred indoors during the cold season. The questionnaire survey showed that the most prevalent symptom was shortness of breath (25.6 %), followed by rhinitis (20.8 %) and wheeze (14.4 %), with generally no prevalence difference between urban and peri-urban neighborhoods. Notably, despite the sparse garden plant community in the cold season, the abundance of Oleaceae trees showed an inverse relationship with the RDs-associated microbes as well as the prevalences of RDs based on the structural equation model results. This finding was largely supported by the negative effect of Oleaceae trees on the population of Streptococcus anginosus (qPCR) which was a dominant species transferred indoors in the cold season, given that S. anginosus is highly associated with rhinitis and rhinoconjunctivitis. Taken together, our findings suggest a strong association between the Oleaceae trees, the AMTI and the prevalence of RDs, which can shed some lights in the ecological development towards respiratory safe environment in cities.

Cultivar-dependent differences in plant bud microbiome and functional gene pathways in woody plants commonly used in urban green space

Plant richness and microbiota have been associated with plant health; hardly any studies have investigated how plant taxa differs in microbiota in the context of human health. We investigated the microbial differences in buds of 83 woody plant taxa used in urban green spaces in hemiboreal climate, using 16S rRNA and whole metagenome shotgun sequencing. Bud microbial community was the richest in Cotoneaster Nanshan and C. integerrimus, and Malus domestica cultivars "Sandra" and "Lobo" and poorest in Ribes glandulosum. Metagenomic shotgun sequencing of two M. domestica and four Ribes varieties confirmed differences in taxa in bud microbiota and indicated higher siderophore synthesis in Malus. Microbial richness, including bacteria, archaea, and viruses, and functional richness of gene pathways was higher in Malus compared to Ribes. The 10 most abundant amplicon sequence units, often referred as species, belonged to the phylum Proteobacteria. The differences between plant taxa were evident in classes Alpha- and Gammaproteobacteria, known for potential human health benefits. Since environmental microbiota contributes to human microbiota and immunoregulation, horticultural cultivars hosting rich microbiota may have human health benefits. Further studies are needed to confirm the effectiveness of microbially-oriented plant selection in optimizing human microbiota and planetary health.

Green space quantity and exposure in relation to the risk of immune-mediated diseases: a scoping review

The growing global incidence of immune-mediated and inflammatory diseases (IMIDs) is worrisome, with evidence suggesting that environmental factors, notably urbanization and the reduction of green spaces, may act as potential instigators. However, conflicting findings in studies necessitate a closer examination of recent research (January 2020 - February 2024) to elucidate the factors contributing to these inconsistencies. This review explores study protocols to avoid erroneously endorsing the null hypothesis of no association between green space coverage and IMID risks. A literature search adhering to PRISMA-ScR guidelines yielded 46 relevant papers from Google Scolar and Pub Meb. The studies varied in design, with 17 being longitudinal, 24 cross-sectional, and five focusing on longitudinal parent-offspring connections. Geographic scope differed, with 21 multi-location and 25 single-location studies. Participant numbers ranged from 144 to 982,131 across diverse demographics. Additionally, some studies examined disease frequencies in large groups (several million people) residing in specific regions. Green space metrics encompassed NDVI, land cover data, plant biodiversity, and novel indexes, measured within 7.5-5000 m diameter buffers around residences or schools. The review advises against making definitive statements regarding the relationship between urban green spaces and the prevalence of IMIDs. It suggests that inconsistencies in study results may stem from variations in study designs and methodologies, as well as the complex, interacting mechanisms through which green spaces affect immune health. Future research recommendations include larger cohorts, early-life exposure data, and testing specific hypotheses related to vegetation types and participants' genetic predispositions.

Exposure to greenspaces sourced soils improves mice gut microbiota

Greenspaces are important components of our living environment and have been linked to various human health. However, the mechanisms underlying the linkages remain unclear. Enriching microbiota has emerged as a novel mechanism, but the corresponding evidence is still limited. We collected soil samples from forest land, grassland, and barren land in Zunyi City, southwestern China and prepared soil solutions. A total of 40 BALB/c mice were evenly divided into normal control group, model control group, forest soil group, grassland soil group, and barren land soil group. After establishing the pseudo germ-free mouse model, different soil solutions were administered through gavage, lasting for seven weeks. Fecal samples were collected and a 16S rRNA high-throughput sequencing analysis was performed. Then, alpha- and beta-diversity were calculated and employed to estimate the effects of soil exposures on mice gut microbial diversity and composition. Further, Linear Discriminant Analysis Effect Size (LEfSe) analysis was carried out to evaluate the effects of soil exposures on gut microbiota specific genera abundances and functional pathways. Compared to mice exposed to barren land soils, those exposed to soils sourced from forest land showed an increase of 0.43 and 70.63 units in the Shannon index and the Observed ASVs, respectively. In addition, exposure to soils sourced from forest land and grassland resulted in healthier changes (i.e., more short-chain fatty acids (SCFAs)-producing bacteria) in gut microbiota than those from barren land. Furthermore, mice exposed to forest soil and grassland soil showed enrichment in 5 and 3 pathways (e.g., butanoate metabolism) compared to those exposed to barren land soil, respectively. In conclusion, exposure to various greenspaces soils may modify the gut microbial communities of mice, potentially fostering a more beneficial microbiota profile. Further better-designed studies are needed to validate the current findings and to explore the effects of greenspace related gut microbiota on human health.

A 15-day pilot biodiversity intervention with horses in a farm system leads to gut microbiome rewilding in 10 urban Italian children

To provide some glimpses on the possibility of shaping the human gut microbiome (GM) through probiotic exchange with natural ecosystems, here we explored the impact of 15 days of daily interaction with horses on the GM of 10 urban-living Italian children. Specifically, the children were in close contact with the horses in an "educational farm", where they spent almost 10 h/day interacting with the animals. The children's GM was assessed before and after the horse interaction using metabarcoding sequencing and shotgun metagenomics, along with the horses' skin, oral and fecal microbiomes. Targeted metabolomic analysis for GM-produced beneficial metabolites (i.e., short-chain fatty acids) in the children's feces was also performed. Interaction with horses facilitated the acquisition of health-related traits in the children's GM, such as increased diversity, enhanced butyrate production and an increase in several health-promoting species considered to be next-generation probiotics. Among these, the butyrate producers Facecalibacterium prausnitzii and F. duncaniae and a species belonging to the order Christensenellales. Interaction with horses was also associated with increased proportions of Eggerthella lenta, Gordonibacter pamelae and G. urolithinfaciens, GM components known to play a role in the bioconversion of dietary plant polyphenols into beneficial metabolites. Notably, no increase in potentially harmful traits, including toxin genes, was observed. Overall, our pilot study provides some insights on the existence of possible health-promoting exchanges between children and horses microbiomes. It lays the groundwork for an implemented and more systematic enrollment effort to explore the full complexity of human GM rewilding through exchange with natural ecosystems, aligning with the One Health approach.

The developing immune system in preterm born infants: From contributor to potential solution for respiratory tract infections and wheezing

Moderate-late preterm-born infants experience more frequent and severe respiratory tract infections and wheezing compared to term-born infants. Decreasing the risk on respiratory tract infections and wheezing in this group is vital to improve quality of life and reduce medical consumption during infancy, but also to reduce the risk on asthma and COPD later in life. Until now, moderate-late preterm infants are underrepresented in research and mechanisms underlying their morbidity are largely unknown, although they represent 80% of all preterm-born infants. In order to protect these infants effectively, it is essential to understand the role of the immune system in early life respiratory health and to identify strategies to optimize immune development and respiratory health. This review elaborates on risk factors and preventative measures concerning respiratory tract infections and wheezing in preterm-born infants, exploring their impact on the immune system and microbiome. Factors discussed are early life antibiotic use, birth mode, feeding type and living environment. Further, differences in adaptive and innate immune maturation between term and preterm infants are discussed, as well as differences in local immune reactions in the lungs. Finally, preventative strategies are being explored, including microbiota transplantation, immune modulation (through pre-, pro-, syn- and postbiotics, bacterial lysates, vaccinations, and monoclonal antibodies) and antibiotic prophylaxis.

Production, analysis, and safety assessment of a soil and plant-based natural material with microbiome- and immune-modulatory effects

It has been suggested that reduced contact with microbiota from the natural environment contributes to the rising incidence of immune-mediated inflammatory disorders (IMIDs) in western, highly urbanized societies. In line with this, we have previously shown that exposure to environmental microbiota in the form of a blend comprising of soil and plant-based material (biodiversity blend; BDB) enhances the diversity of human commensal microbiota and promotes immunoregulation that may be associated with a reduced risk for IMIDs. To provide a framework for future preclinical studies and clinical trials, this study describes how the preparation of BDB was standardized, its microbial content analysed and safety assessments performed. Multiple batches of BDB were manufactured and microbial composition analysed using 16S rRNA gene sequencing. We observed a consistently high alpha diversity and relative abundance of bacteria normally found in soil and vegetation. We also found that inactivation of BDB by autoclaving effectively inactivates human and murine bacteria, viruses and parasites. Finally, we demonstrate that experimental mice prone to develop IMIDs (non-obese diabetic, NOD, mouse model) can be exposed to BDB without causing adverse effects on animal health and welfare. Our study provides insights into a potentially safe, sustainable, and cost-effective approach for simulating exposure to natural microbiota, which could have substantial impacts on health and socio-economic factors.

Planetary boundaries transgressions: A review on the implications to public health

This literature review systematically examines the impacts of violating planetary boundaries from 2009 to 2023, emphasizing the implications for human health. Planetary boundaries define safe operational limits for Earth's systems, and their transgression poses significant threats to environmental stability and public health. This paper reviews extensive research on the health effects of breaches in these boundaries, including climate change, biodiversity loss, freshwater use, and aerosol loading. The review integrates findings from numerous studies, providing a critical overview of health impacts across various global regions. The analysis underscores the intricate links between planetary boundaries breaching impacts, highlighting urgent policy and governance challenges. The study's outcomes aim to inform policymakers, businesses, and communities, promoting sustainable development and resilience in the face of escalating global challenges.

The role of early life factors and green living environment in the development of gut microbiota in infancy: Population-based cohort study

OBJECTIVE

Early life microbial exposure influences the composition of gut microbiota. We investigated how early life factors, and the green living environment around infants' homes, influence the development of gut microbiota during infancy by utilizing data from the Steps to Healthy Development follow-up study (the STEPS study).

METHODS

The gut microbiota was analyzed at early (∼3 months, n = 959), and late infancy (∼13 months, n = 984) using 16S rRNA amplicon sequencing, and combined with residential green environment, measured as (1) Normalized Difference Vegetation Index, (2) Vegetation Cover Diversity, and (3) Naturalness Index within a 750 m radius. We compared gut microbiota diversity and composition between early and late infancy, identified significant individual and family level early life factors influencing gut microbiota, and determined the role of the residential green environment measures on gut microbiota development.

RESULTS

Alpha diversity (t-test, p < 0.001) and beta diversity (PERMANOVA, R2 = 0.095, p < 0.001) differed between early and late infancy. Birth mode was the strongest contributor to the gut microbiota community composition in early infancy (PERMANOVA, R2 = 0.005, p < 0.01) and the presence of siblings in late infancy (PERMANOVA, R2 = 0.007, p < 0.01). Residential green environment showed no association with community composition, whereas time spend outdoors did (PERMANOVA, R2 = 0.002, p < 0.05). Measures of greenness displayed a statistically significant association with alpha diversity during early infancy, not during late infancy (glm, p < 0.05). In adjusted analysis, the associations remained only with the Naturalness Index, where higher human impact on living environment was associated with decreased species richness (glm, Observed richness, p < 0.05).

CONCLUSIONS

The role of the residential green environment to the infant gut microbiota is especially important in early infancy, however, other early life factors, such as birth mode and presence of sibling, had a more significant effect on the overall community composition.

Greenness on mortality of infant and under-5 child: A nationwide study in 147 Chinese cities

BACKGROUND

Higher greenness was associated with a lower risk of adult mortality. However, the effects of greenness on the mortality of infant and child under-5 have not been fully examined.

OBJECTIVES

The association of greenness on the infant mortality rate (IMR) and child under-5 mortality rate (U5MR) in 147 Chinese cities from 2009 to 2020 was evaluated.

METHODS

Average and maximum annual population-weighted greenness, IMR (per 1000 live births), and U5MR (per 1000 live births) in 147 cities from 2009 to 2020 were collected, and a longitudinal panel study was conducted. Greenness exposure was evaluated using satellite-derived data at a spatial resolution of 250 m ×250 m in urban regions, and linear mixed-effect models were applied to assess the associations between greenness and IMR or U5MR in China.

RESULTS

This national study showed that long-term exposure to greenness was associated with lower IMR and U5MR, respectively. Specifically, a 0.1 increase of Normalized Difference Vegetation Index (NDVI) in greenness was statistically significant with a decrease in IMR (-1.05 ‰, 95 % CI: -1.48, -0.63 ‰) and U5MR (-1.82 ‰, 95 % CI: -2.39, -1.25 ‰) in fully-adjusted model, respectively. In the stratified analyses, greenness effects on U5MR in the western (-2.33 ‰, 95 % CI: -3.43, -1.23 ‰) and central regions (-2.06 ‰, 95 % CI: -3.01, -1.10 ‰) were stronger than that in the eastern region (-0.86 ‰, 95 % CI: -1.66, -0.07 ‰).

CONCLUSIONS

This nationwide study indicated that exposure to higher greenness was associated with lower mortality rates in infant and child under-5 in China.

Using patterns of shared taxa to infer bacterial dispersal in human living environment in urban and rural areas

Contact with environmental microbial communities primes the human immune system. Factors determining the distribution of microorganisms, such as dispersal, are thus important for human health. Here, we used the relative number of bacteria shared between environmental and human samples as a measure of bacterial dispersal and studied these associations with living environment and lifestyles. We analyzed amplicon sequence variants (ASVs) of the V4 region of 16S rDNA gene from 347 samples of doormat dust as well as samples of saliva, skin swabs, and feces from 53 elderly people in urban and rural areas in Finland at three timepoints. We first enumerated the ASVs shared between doormat and one of the human sample types (i.e., saliva, skin swab, or feces) of each individual subject and calculated the shared ASVs as a proportion of all ASVs in the given sample type of that individual. We observed that the patterns for the proportions of shared ASVs differed among seasons and human sample type. In skin samples, there was a negative association between the proportion of shared ASVs and the coverage of built environment (a proxy for degree of urbanization), whereas in saliva data, this association was positive. We discuss these findings in the context of differing species pools in urban and rural environments.

IMPORTANCE

Understanding how environmental microorganisms reach and interact with humans is a key question when aiming to increase human contacts with natural microbiota. Few methods are suitable for studying microbial dispersal at relatively large spatial scales. Thus, we tested an indirect method and studied patterns of bacterial taxa that are shared between humans and their living environment.

Reduce, reinforce, and replenish: safeguarding the early-life microbiota to reduce intergenerational health disparities

Socioeconomic (SE) disparity and health inequity are closely intertwined and associated with cross-generational increases in the rates of multiple chronic non-communicable diseases (NCDs) in North America and beyond. Coinciding with this social trend is an observed loss of biodiversity within the community of colonizing microbes that live in and on our bodies. Researchers have rightfully pointed to the microbiota as a key modifiable factor with the potential to ease existing health inequities. Although a number of studies have connected the adult microbiome to socioeconomic determinants and health outcomes, few studies have investigated the role of the infant microbiome in perpetuating these outcomes across generations. It is an essential and important question as the infant microbiota is highly sensitive to external forces, and observed shifts during this critical window often portend long-term outcomes of health and disease. While this is often studied in the context of direct modulators, such as delivery mode, family size, antibiotic exposure, and breastfeeding, many of these factors are tied to underlying socioeconomic and/or cross-generational factors. Exploring cross-generational socioeconomic and health inequities through the lens of the infant microbiome may provide valuable avenues to break these intergenerational cycles. In this review, we will focus on the impact of social inequality in infant microbiome development and discuss the benefits of prioritizing and restoring early-life microbiota maturation for reducing intergenerational health disparities.

Modelling a Western Lifestyle in Mice: A Novel Approach to Eradicating Aerobic Spore-Forming Bacteria from the Colonic Microbiome and Assessing Long-Term Clinical Outcomes

INTRODUCTION

The environmentally acquired aerobic spore-forming (EAS-Fs) bacteria that are ubiquitous in nature (e.g., soil) are transient colonisers of the mammalian gastro-intestinal tract. Without regular exposure, their numbers quickly diminish. These species of bacteria have been suggested to be essential to the normal functioning of metabolic and immunogenic health. The modern Western lifestyle restricts exposure to these EAS-Fs, possibly explaining part of the pathogenesis of many Western diseases. To date, the only animal studies that address specific microbiome modelling are based around germ-free animals. We have designed a new animal model that specifically restricts exposure to environmental sources of bacteria.

METHODOLOGY

A new protocol, termed Super Clean, which involves housing mice in autoclaved individually ventilated cages (IVCs), with autoclaved food/water and strict ascetic handling practice was first experimentally validated. The quantification of EAS-Fs was assessed by heat-treating faecal samples and measuring colony-forming units (CFUs). This was then compared to mice in standard conditions. Mice were housed in their respective groups from birth until 18 months. Stool samples were taken throughout the experiment to assess for abundance in transiently acquired environmental bacteria. Clinical, biochemical, histological, and gene expression markers were analysed for diabetes, hypercholesterolaemia, obesity, inflammatory bowel disease, and non-alcoholic fatty liver disease (the "diseases of the West").

RESULTS

Our results show that stringent adherence to the Super Clean protocol produces a significantly decreased abundance of aerobic spore-forming Bacillota after 21 days. This microbiomic shift was correlated with significantly increased levels of obesity and impaired glucose metabolism. There was no evidence of colitis, liver disease or hypercholesterolaemia.

CONCLUSIONS

This new murine model successfully isolates EAS-Fs and has potential utility for future research, allowing for an investigation into the clinical impact of living in relative hygienic conditions.

The climate change-pollution-aerobiome nexus: A 'systems thinking' mini-review

The interrelationship between climate change, pollution and the aerobiome (the microbiome of the air) is a complex ecological dynamic with profound implications for human and ecosystem health. This mini-review explores the multifaceted relationships among these factors. By synthesising existing research and integrating interdisciplinary perspectives, we examine the mechanisms driving interactions within the climate change-pollution-aerobiome nexus. We also explore synergistic and cascading effects and potential impacts on human health (including both communicable and non-communicable diseases) and that of wider ecosystems. Based on our mini-review results, climate change influences air pollution and, independently, air pollution affects the composition, diversity and activity of the aerobiome. However, we apply a 'systems thinking' approach and create a set of systems diagrams to show that climate change likely influences the aerobiome (including bacteria and fungi) via climate change-pollution interactions in complex ways. Due to the inherent complexity of these systems, we emphasise the importance of holistic and/or interdisciplinary approaches and collaborative efforts in understanding this nexus to safeguard planetary health in an era of rapid environmental change.

A microbial symphony: a literature review of the factors that orchestrate the colonization dynamics of the human colonic microbiome during infancy and implications for future health

Since the advent of new sequencing and bioinformatic technologies, our understanding of the human microbiome has expanded rapidly over recent years. Numerous studies have indicated causal links between alterations to the microbiome and a range of pathological conditions. Furthermore, a large body of epidemiological data is starting to suggest that exposure, or lack thereof, to specific microbial species during the first five years of life has key implications for long-term health outcomes. These include chronic inflammatory and metabolic conditions such as diabetes, asthma, inflammatory bowel disease (IBD), and obesity, with the effects lasting into adulthood. Human microbial colonisation during these first five years of life is a highly dynamic process, with multiple environmental exposures recently being characterised to have influence before the microbiome stabilises and resembles that of an adult at 3-5 years. This short period of time, known as the window of opportunity, appears to "prime" immunoregulation for later life. Understanding and appreciating this aspect of human physiology is therefore crucial for clinicians, scientists, and public health officials. This review outlines the most recent evidence for the pre- and post-natal environments that order the development of the microbiome, how these influences metabolic and immunoregulatory pathways, and their associated health outcomes. It also discusses the limitations of the current knowledge base, and describes the potential microbiome-mediated interventions and public health measures that may have therapeutic potential in the future.

Birth and household exposures are associated with changes to skin bacterial communities during infancy

Background and objectives

Microbial exposures during infancy shape the development of the microbiome, the collection of microbes living in and on the body, which in turn directs immune system training. Newborns acquire a substantial quantity of microbes during birth and throughout infancy via exposure to microbes in the physical and social environment. Alterations to early life microbial environments may give rise to mismatches, where environmental, cultural and behavioral changes that outpace the body's adaptive responses can lead to adverse health outcomes, particularly those related to microbiome development and immune system regulation.

Methods

This study explored the development of the skin microbiome among infants born in Chicago, USA. We collected skin swab microbiome samples from 22 mother-infant dyads during the first 48 h of life and again at 6 weeks postpartum. Mothers provided information about social environments and hygiene behaviors that may impact infants' microbial exposures.

Results

Analysis of amplicon bacterial gene sequencing data revealed correlations between infant skin bacterial abundances shortly after birth and factors such as antibiotic exposure and receiving a bath in the hospital. The composition of the infant microbiome at 6 weeks of age was associated with interactions with caregivers and infant feeding practices. We also found shifts in maternal skin microbiomes that may reflect increased hygiene practices in the hospital.

Conclusions and implications

Our data suggest that factors related to the birth and household environment can impact the development of infant skin microbiomes and point to practices that may produce mismatches for the infant microbiome and immune system.

Health by design; optimising our urban environmental microbiomes for human health

Humans have evolved in direct and intimate contact with their environment and the microbes that it contains, over a period of 2 million years. As a result, human physiology has become intrinsically linked to environmental microbiota. Urbanisation has reduced our exposure to harmful pathogens, however there is now increasing evidence that these same health-protective improvements in our environment may also be contributing to a hidden disease burden: immune dysregulation. Thoughtful and purposeful design has the potential to ameliorate these health concerns by providing sources of microbial diversity for human exposure. In this narrative review, we highlight the role of environmental microbiota in human health and provide insights into how we can optimise human health through well-designed cities, urban landscapes and buildings. The World Health Organization recommends there should be at least one public green space of least 0.5 ha in size within 300m of a place of residence. We argue that these larger green spaces are more likely to permit functioning ecosystems that deliver ecosystem services, including the provision of diverse aerobiomes. Urban planning must consider the conservation and addition of large public green spaces, while landscape design needs to consider how to maximise environmental, social and public health outcomes, which may include rewilding. Landscape designers need to consider how people use these spaces, and how to optimise utilisation, including for those who may experience challenges in access (e.g. those living with disabilities, people in residential care). There are also opportunities to improve health via building design that improves access to diverse environmental microbiota. Considerations include having windows that open, indoor plants, and the relationship between function, form and organization. We emphasise possibilities for re-introducing potentially health-giving microbial exposures into urban environments, particularly where the benefits of exposure to biodiverse environments may have been lost.

The influence of pre- and postnatal exposure to air pollution and green spaces on infant's gut microbiota: Results from the MAMI birth cohort study

BACKGROUND

Animal and human studies indicate that exposure to air pollution and natural environments might modulate the gut microbiota, but epidemiological evidence is very scarce.

OBJECTIVES

To assess the potential impact of pre- and postnatal exposure to air pollution and green spaces on infant gut microbiota assembly and trajectories during the first year of life.

METHODS

MAMI ("MAternal MIcrobes") birth cohort (Valencia, Spain, N = 162) was used to study the impact of environmental exposure (acute and chronic) on infant gut microbiota during the first year of life (amplicon-based 16S rRNA sequencing). At 7 days and at 1, 6 and 12 months, residential pre- and postnatal exposure to air pollutants (NO2, black carbon -BC-, PM2.5 and O3) and green spaces indicators (NDVI and area of green spaces at 300, 500 and 1000 m buffers) were obtained. For the association between exposures and alpha diversity indicators linear regression models (cross-sectional analyses) and mixed models, including individual as a random effect (longitudinal analyses), were applied. For the differential taxon analysis, the ANCOM-BC package with a log count transformation and multiple-testing corrections were used.

RESULTS

Acute exposure in the first week of life and chronic postnatal exposure to NO2 were associated with a reduction in microbial alpha diversity, while the effects of green space exposure were not evident. Acute and chronic (prenatal or postnatal) exposure to NO2 resulted in increased abundance of Haemophilus, Akkermansia, Alistipes, Eggerthella, and Tyzerella populations, while increasing green space exposure associated with increased Negativicoccus, Senegalimassilia and Anaerococcus and decreased Tyzzerella and Lachnoclostridium populations.

DISCUSSION

We observed a decrease in the diversity of the gut microbiota and signs of alteration in its composition among infants exposed to higher levels of NO2. Increasing green space exposure was also associated with changes in gut microbial composition. Further research is needed to confirm these findings.

Skin exposure to soil microbiota elicits changes in cell-mediated immunity to pneumococcal vaccine

A resilient immune system is characterized by its capacity to respond appropriately to challenges, such as infections, and it is crucial in vaccine response. Here we report a paired randomized intervention-control trial in which we evaluated the effect of microbially rich soil on immune resilience and pneumococcal vaccine response. Twenty-five age and sex matched pairs of volunteers were randomized to intervention and control groups. The intervention group rubbed hands three times a day in microbially rich soil until participants received a pneumococcal vaccine on day 14. Vaccine response, skin and gut bacteriome and blood cytokine levels were analyzed on days 0, 14 and 35. Peripheral blood mononuclear cells (PBMCs) were stimulated with vaccine components and autoclaved soil for cytokine production. Commensal bacterial community shifted only in the intervention group during the 14-day intervention period. When PBMCs collected on day 14 before the vaccination were stimulated with the vaccine components, IFN-y production increased in the intervention but not in the control group. On day 35, vaccination induced a robust antibody response in both groups. In parallel, gut bacterial community was associated with TGF-β plasma levels and TGF-β decrease in plasma was lower in the intervention group. The results indicate that exposure to microbially rich soil can modulate the cell-mediated immunity to components in pneumococcal vaccine.

Healthy childhood development through outdoor risky play: Navigating the balance with injury prevention

Free play is essential for children's development and for their physical, mental, and social health. Opportunities to engage in outdoor free play-and risky play in particular-have declined significantly in recent years, in part because safety measures have sought to prevent all play-related injuries rather than focusing on serious and fatal injuries. Risky play is defined by thrilling and exciting forms of free play that involve uncertainty of outcome and a possibility of physical injury. Proponents of risky play differentiate "risk" from "hazard" and seek to reframe perceived risk as an opportunity for situational evaluation and personal development. This statement weighs the burden of play-related injuries alongside the evidence in favour of risky play, including its benefits, risks, and nuances, which can vary depending on a child's developmental stage, ability, and social and medical context. Approaches are offered to promote open, constructive discussions with families and organizations. Paediatricians are encouraged to think of outdoor risky play as one way to help prevent and manage common health problems such as obesity, anxiety, and behavioural issues.

Le développement sain de l'enfant par le jeu risqué extérieur : un équilibre à trouver avec la prévention des blessures

Le jeu libre est essentiel pour le développement de l'enfant, de même que pour sa santé physique, mentale et sociale. Les occasions de se livrer au jeu libre extérieur, et au jeu risqué en particulier, ont considérablement diminué ces dernières années, en partie parce que les mesures de sécurité ont visé à prévenir toutes les blessures liées aux jeux plutôt que seulement les blessures graves et fatales. Le jeu risqué désigne des formes passionnantes et stimulantes de jeu libre dont l'issue est incertaine et qui comportent une possibilité de blessure physique. Les promoteurs du jeu risqué distinguent le « risque » du « danger » et aspirent à recadrer la perception du risque pour qu'il devienne une occasion d'évaluer une situation et de favoriser le développement personnel. Dans le présent document de principes, les auteures soupèsent le fardeau des blessures liées au jeu par rapport aux données probantes en appui au jeu risqué, notamment les avantages, les risques et les nuances, qui peuvent varier en fonction de l'étape de développement de l'enfant, de ses aptitudes et du contexte social et médical. Elles proposent des approches pour promouvoir des échanges ouverts et constructifs avec les familles et les organisations. Les pédiatres sont invités à percevoir le jeu risqué extérieur comme un moyen de contribuer à prévenir et à gérer des problèmes de santé courants tels que l'obésité, l'anxiété et les problèmes de comportement.

Urban sports fields support higher levels of soil butyrate and butyrate-producing bacteria than urban nature parks

Butyrate-producing bacteria colonise the gut of humans and non-human animals, where they produce butyrate, a short-chain fatty acid with known health benefits. Butyrate-producing bacteria also reside in soils and soil bacteria can drive the assembly of airborne bacterial communities (the aerobiome). Aerobiomes in urban greenspaces are important reservoirs of butyrate-producing bacteria as they supplement the human microbiome, but soil butyrate producer communities have rarely been examined in detail. Here, we studied soil metagenome taxonomic and functional profiles and soil physicochemical data from two urban greenspace types: sports fields (n = 11) and nature parks (n = 22). We also developed a novel method to quantify soil butyrate and characterised the in situ activity of butyrate-producing bacteria. We show that soil butyrate was higher in sports fields than nature parks and that sports fields also had significantly higher relative abundances of the terminal butyrate production genes buk and butCoAT than nature parks. Soil butyrate positively correlated with buk gene abundance (but not butCoAT). Soil moisture (r = .50), calcium (r = -.62), iron (ρ = .54), ammonium nitrogen (ρ = .58) and organic carbon (r = .45) had the strongest soil abiotic effects on soil butyrate concentrations and iron (ρ = .56) and calcium (ρ = -.57) had the strongest soil abiotic effects on buk read abundances. Overall, our findings contribute important new insights into the role of sports fields as key exposure reservoirs of butyrate producing bacteria, with important implications for the provision of microbiome-mediated human health benefits via butyrate.

Short-term passive greenspace exposures have little effect on nasal microbiomes: A cross-over exposure study of a Māori cohort

Indigenous health interventions have emerged in New Zealand aimed at increasing people's interactions with and exposure to macro and microbial diversity. Urban greenspaces provide opportunities for people to gain such exposures. However, the dynamics and pathways of microbial transfer from natural environments onto a person remain poorly understood. Here, we analysed bacterial 16S rRNA amplicons in air samples (n = 7) and pre- and post-exposure nasal samples (n = 238) from 35 participants who had 30-min exposures in an outdoor park. The participants were organised into two groups: over eight days each group had two outdoor park exposures and two indoor office exposures, with a cross-over study design and washout days between exposure days. We investigated the effects of participant group, location (outdoor park vs. indoor office), and exposures (pre vs. post) on the nasal bacterial community composition and three key suspected health-associated bacterial indicators (alpha diversity, generic diversity of Gammaproteobacteria, and read abundances of butyrate-producing bacteria). The participants had distinct nasal bacterial communities, but these communities did not display notable shifts in composition following exposures. The community composition and key health bacterial indicators were stable throughout the trial period, with no clear or consistent effects of group, location, or exposure. We conclude that 30-min exposure periods to urban greenspaces are unlikely to create notable changes in the nasal microbiome of visitors, which contrasts with previous research. Our results suggest that longer exposures or activities that involves closer interaction with microbial rich ecological components (e.g., soil) are required for greenspace exposures to result in noteworthy changes in the nasal microbiome.

Impact of Plant-Microbe Interactions with a Focus on Poorly Investigated Urban Ecosystems-A Review

The urbanization process, which began with the Industrial Revolution, has undergone a considerable increase over the past few decades. Urbanization strongly affects ecological processes, often deleteriously, because it is associated with a decrease in green spaces (areas of land covered by vegetation), loss of natural habitats, increased rates of species extinction, a greater prevalence of invasive and exotic species, and anthropogenic pollutant accumulation. In urban environments, green spaces play a key role by providing many ecological benefits and contributing to human psychophysical well-being. It is known that interactions between plants and microorganisms that occur in the rhizosphere are of paramount importance for plant health, soil fertility, and the correct functioning of plant ecosystems. The growing diffusion of DNA sequencing technologies and "omics" analyses has provided increasing information about the composition, structure, and function of the rhizomicrobiota. However, despite the considerable amount of data on rhizosphere communities and their interactions with plants in natural/rural contexts, current knowledge on microbial communities associated with plant roots in urban soils is still very scarce. The present review discusses both plant-microbe dynamics and factors that drive the composition of the rhizomicrobiota in poorly investigated urban settings and the potential use of beneficial microbes as an innovative biological tool to face the challenges that anthropized environments and climate change impose. Unravelling urban biodiversity will contribute to green space management, preservation, and development and, ultimately, to public health and safety.

Nurturing future leaders for nature: the example of the UK's National Education Nature Park

This piece reviews the evidence on the effect that engaging with nature has on school-age children's future attitudes and behaviour towards nature. It also looks into the impact engaging with nature has on children and young people's physical, mental and personal development and the evidence on how much time children in England are spending in natural environments. It then presents a UK Government project, the National Education Nature Park (NENP), intended to increase children in England's access to nature by developing nature spaces within the grounds of educational institutions. It concludes with suggestions for how the implementation of the NENP could be used to learn more about the effect that engaging with nature has on children alongside understanding how school-based nature projects could benefit the local environment. This article is part of the theme issue 'Bringing nature into decision-making'.

Childcare centre soil microbiomes are influenced by substrate type and surrounding vegetation condition

Urban development has profoundly reduced human exposure to biodiverse environments, which is linked to a rise in human disease. The 'biodiversity hypothesis' proposes that contact with diverse microbial communities (microbiota) benefits human health, as exposure to microbial diversity promotes immune training and regulates immune function. Soils and sandpits in urban childcare centres may provide exposure to diverse microbiota that support immunoregulation at a critical developmental stage in a child's life. However, the influence of outdoor substrate (i.e., sand vs. soil) and surrounding vegetation on these environmental microbiota in urban childcare centres remains poorly understood. Here, we used 16S rRNA amplicon sequencing to examine the variation in bacterial communities in sandpits and soils across 22 childcare centres in Adelaide, Australia, plus the impact of plant species richness and habitat condition on these bacterial communities. We show that sandpits had distinct bacterial communities and lower alpha diversity than soils. In addition, we found that plant species richness in the centres' yards and habitat condition surrounding the centres influenced the bacterial communities in soils but not sandpits. These results demonstrate that the diversity and composition of childcare centre sandpit and soil bacterial communities are shaped by substrate type, and that the soils are also shaped by the vegetation within and surrounding the centres. Accordingly, there is potential to modulate the exposure of children to health-associated bacterial communities by managing substrates and vegetation in and around childcare centres.

Evolution and the critical role of the microbiota in the reduced mental and physical health associated with low socioeconomic status (SES)

The evolution of the gut-microbiota-brain axis in animals reveals that microbial inputs influence metabolism, the regulation of inflammation and the development of organs, including the brain. Inflammatory, neurodegenerative and psychiatric disorders are more prevalent in people of low socioeconomic status (SES). Many aspects of low SES reduce exposure to the microbial inputs on which we are in a state of evolved dependence, whereas the lifestyle of wealthy citizens maintains these exposures. This partially explains the health deficit of low SES, so focussing on our evolutionary history and on environmental and lifestyle factors that distort microbial exposures might help to mitigate that deficit. But the human microbiota is complex and we have poor understanding of its functions at the microbial and mechanistic levels, and in the brain. Perhaps its composition is more flexible than the microbiota of animals that have restricted habitats and less diverse diets? These uncertainties are discussed in relation to the encouraging but frustrating results of attempts to treat psychiatric disorders by modulating the microbiota.

INVITED REVIEW: Impact of Maternal Health and Nutrition on the Microbiome and Immune Development of Neonatal Calves

This comprehensive review highlights the intricate interplay between maternal factors and the co-development of the microbiome and immune system in neonatal calves. Based on human and mouse studies, multiple prenatal and postnatal factors influence this process by altering the host-associated microbiomes (gut, respiratory tract, skin), microbial colonization trajectories, and priming of the immune systems (mucosal and systemic). This review emphasizes the importance of early life exposure, highlighting postnatal factors that work in synergy with maternal factors in further finetuning the co-development of the neonatal microbiome and immunity. In cattle, there is a general lack of research to identify the maternal effect on the early colonization process of neonatal calves (gut, respiratory tract) and its impact on the priming of the immune system. Past studies have primarily investigated the maternal effects on the passive transfer of immunity at birth. The co-development process of the microbiome and immune system is vital for lifelong health and production in cattle. Therefore, comprehensive research beyond the traditional focus on passive immunity is an essential step in this endeavor. Calf microbiome research reports the colonization of diverse bacterial communities in newborns, which is affected by the colostrum feeding method immediately after birth. In contrast to human studies reporting a strong link between maternal and infant bacterial communities, there is a lack of evidence to clearly define cow-to-calf transmission in cattle. Maternal exposure has been shown to promote the colonization of beneficial bacteria in neonatal calves. Nonetheless, calf microbiome research lacks links to early development of the immune system. An in-depth understanding of the impact of maternal factors on microbiomes and immunity will improve the management of pregnant cows to raise immune-fit neonatal calves. It is essential to investigate the diverse effects of maternal health conditions and nutrition during pregnancy on the gut microbiome and immunity of neonatal calves through collaboration among researchers from diverse fields such as microbiology, immunology, nutrition, veterinary science, and epidemiology.

Influence of Compost Amendments on Soil and Human Gastrointestinal Bacterial Communities during a Single Gardening Season

To measure associations between gardening with different compost amendments and the human gut microbiota composition, gardeners (n = 25) were provided with one of three types of compost: chicken manure (CM), dairy manure and plant material (DMP), or plant-based (P). Stool samples were collected before gardening (T1), after compost amendment (T2), and at peak garden harvest (T3). Compost and soil samples were collected. DNA was extracted, 16S rRNA libraries were established, and libraries were sequenced by Illumina MiSeq. Sequences were processed using mothur, and data were analyzed in R software version 4.2.2. Fast expectation-maximization microbial source tracking analysis was used to determine stool bacteria sources. At T2/T3, the gut microbiotas of P participants had the lowest Shannon alpha diversity, which was also the trend at T1. In stool from T2, Ruminococcus 1 were less abundant in the microbiotas of those using P compost as compared to those using CM or DMP. At T2, Prevotella 9 had the highest abundance in the microbiotas of those using CM compost. In participants who used CM compost to amend their gardening plots, a larger proportion of the human stool bacteria were sourced from CM compared to soil. Soil exposure through gardening was associated with a small but detectable change in the gardeners' gut microbiota composition. These results suggest that human interactions with soil through gardening could potentially impact health through alterations to the gut microbiota.

Urban indoor gardening enhances immune regulation and diversifies skin microbiota - A placebo-controlled double-blinded intervention study

According to the hygiene and biodiversity hypotheses, frequent exposure to environmental microbiota, especially through soil contact, diversifies commensal microbiota, enhances immune modulation, and ultimately lowers the risk of immune-mediated diseases. Here we test the underlying assumption of the hygiene and biodiversity hypotheses by instructing volunteers to grow edible plants indoors during the winter season when natural exposure to environmental microbiota is low. The one-month randomized, placebo-controlled double-blind trial consisted of two treatments: participants received either microbially diverse growing medium or visually similar but microbially poor growing medium. Skin microbiota and a panel of seven immune markers were analyzed in the beginning of the trial and after one month. The diversity of five bacterial phyla (Bacteroidetes, Planctomycetes, Proteobacteria, Cyanobacteria, and Verrucomicrobia) and one class (Bacteroidia) increased on the skin of participants in the intervention group while no changes were observed in the placebo group. The number of nodes and edges in the co-occurrence networks of the skin bacteria increased on average three times more in the intervention group than in the placebo group. The plasma levels of the immunomodulatory cytokine interleukin 10 (IL-10) increased in the intervention group when compared with the placebo group. A similar trend was observed in the interleukin 17A (IL-17A) levels and in the IL-10:IL-17A ratios. Participants in both groups reported high satisfaction and adherence to the trial. The current study provides evidence in support of the core assumption of the hygiene and biodiversity hypotheses of immune-mediated diseases. Indoor urban gardening offers a meaningful and convenient approach for increasing year-round exposure to environmental microbiota, paving the way for other prophylactic practices that might help prevent immune-mediated diseases.

Impact of climate change on immune responses and barrier defense

Climate change is not just jeopardizing the health of our planet but is also increasingly affecting our immune health. There is an expanding body of evidence that climate-related exposures such as air pollution, heat, wildfires, extreme weather events, and biodiversity loss significantly disrupt the functioning of the human immune system. These exposures manifest in a broad range of stimuli, including antigens, allergens, heat stress, pollutants, microbiota changes, and other toxic substances. Such exposures pose a direct and indirect threat to our body's primary line of defense, the epithelial barrier, affecting its physical integrity and functional efficacy. Furthermore, these climate-related environmental stressors can hyperstimulate the innate immune system and influence adaptive immunity-notably, in terms of developing and preserving immune tolerance. The loss or failure of immune tolerance can instigate a wide spectrum of noncommunicable diseases such as autoimmune conditions, allergy, respiratory illnesses, metabolic diseases, obesity, and others. As new evidence unfolds, there is a need for additional research in climate change and immunology that covers diverse environments in different global settings and uses modern biologic and epidemiologic tools.

Diversity Analysis of Intestinal Bifidobacteria in the Hohhot Population

(1) Background: Bifidobacterium plays a pivotal role within the gut microbiota, significantly affecting host health through its abundance and composition in the intestine. Factors such as age, gender, and living environment exert considerable influence on the gut microbiota, yet scant attention has been directed towards understanding the specific effects of these factors on the Bifidobacterium population. Therefore, this study focused on 98 adult fecal samples to conduct absolute and relative quantitative analyses of bifidobacteria. (2) Methods: Using droplet digital PCR and the PacBio Sequel II sequencing platform, this study sought to determine the influence of various factors, including living environment, age, and BMI, on the absolute content and biodiversity of intestinal bifidobacteria. (3) Results: Quantitative results indicated that the bifidobacteria content in the intestinal tract ranged from 106 to 109 CFU/g. Notably, the number of bifidobacteria in the intestinal tract of the school population surpassed that of the off-campus population significantly (p = 0.003). Additionally, the group of young people exhibited a significantly higher count of bifidobacteria than the middle-aged and elderly groups (p = 0.041). The normal-weight group displayed a significantly higher bifidobacteria count than the obese group (p = 0.027). Further analysis of the relative abundance of bifidobacteria under different influencing factors revealed that the living environment emerged as the primary factor affecting the intestinal bifidobacteria structure (p = 0.046, R2 = 2.411). Moreover, the diversity of bifidobacteria in the intestinal tract of college students surpassed that in the out-of-school population (p = 0.034). This was characterized by a notable increase in 11 strains, including B. longum, B. bifidum, and B. pseudolongum, in the intestinal tract of college students, forming a more intricate intestinal bifidobacteria interaction network. (4) Conclusions: In summary, this study elucidated the principal factors affecting intestinal bifidobacteria and delineated their characteristics of intestinal bifidobacteria in diverse populations. By enriching the theory surrounding gut microbiota and health, this study provides essential data support for further investigations into the intricate dynamics of the gut microbiota.

Soil intake modifies the gut microbiota and alleviates Th2-type immune response in an ovalbumin-induced asthma mouse model

Background

A low-clean living environment (LCLE) can increase gut microbial diversity and prevent allergic diseases, whereas gut microbial dysbiosis is closely related to the pathogenesis of asthma. Our previous studies suggested that soil in the LCLE is a key factor in shaping intestinal microbiota. We aimed to explore whether sterilized soil intake as a prebiotic while being incubated with microbes in the air can attenuate mouse asthma inflammation by modifying gut microbiota.

Methods

16S rRNA gene sequencing was used to analyze the gut microbial composition, in combination with immune parameters measured in the lung and serum samples.

Results

16S rRNA gene sequencing results showed significant differences in the fecal microbiota composition between the test and control mice, with a higher abundance of Allobaculum, Alistipes, and Lachnospiraceae_UCG-001, which produce short-chain fatty acids and are beneficial for health in the test mice. Soil intake significantly downregulated the concentrations of IL-4 and IL-9 in serum and increased the expression of IFN-γ, which regulated the Th1/Th2 balance in the lung by polarizing the immune system toward Th1, alleviating ovalbumin-induced asthma inflammation. The effect of sensitization on gut microbiota was greater than that of air microbes and age together but weaker than that of soil.

Conclusions

Soil intake effectively reduced the expression of inflammatory cytokines in asthmatic mice, possibly by promoting the growth of multiple beneficial bacteria. The results indicated that the development of soil-based prebiotic products might be used for allergic asthma management, and our study provides further evidence for the hygiene hypothesis.