Effect of ambient air pollution on the incidence of appendicitis

The hidden threat: Environmental toxins and their effects on gut microbiota

The human gut microbiota (GM), which consists of a complex and diverse ecosystem of bacteria, plays a vital role in overall wellness. However, the delicate balance of this intricate system is being compromised by the widespread presence of environmental toxins. The intricate connection between contaminants in the environment and human well-being has garnered significant attention in recent times. Although many environmental pollutants and their toxicity have been identified and studied in laboratory settings and animal models, there is insufficient data concerning their relevance to human physiology. Consequently, research on the toxicity of environmental toxins in GM has gained prominence in recent years. Various factors, such as air pollution, chemicals, heavy metals, and pesticides, have a detrimental impact on the composition and functioning of the GM. This comprehensive review aims to comprehend the toxic effects of numerous environmental pollutants, including antibiotics, endocrine-disrupting chemicals, heavy metals, and pesticides, on GM by examining recent research findings. The current analysis concludes that different types of environmental toxins can lead to GM dysbiosis and have various potential adverse effects on the well-being of animals. We investigate the alterations to the GM composition induced by contaminants and their impact on overall well-being, providing a fresh perspective on research related to pollutant exposure.

Trends in Simple and Complex Appendicitis in Children and the Potential Correlation to Common Viral Pathogens-A Retrospective Cohort Study between 2010 and 2019 in The Netherlands

The aim of this study was to evaluate the annual, seasonal and monthly trends in children with simple and complex appendicitis and their correlation to common viral pathogens in the Netherlands. A consecutive multicenter retrospective cohort study was performed between 2010 and 2019 including children (<18 years) surgically treated for appendicitis. The primary outcome was the distribution of children with simple and complex appendicitis per year, season and month. Relevant seasonal variation was defined as ≥5%. The secondary outcome was a positive correlation of the number of patients with simple and complex appendicitis to common viral pathogens (data anonymously provided by the Dutch Working Group on Clinical Virology from the Dutch Society for Clinical Microbiology (NVMM)). In total, 896 patients were included: N = 524 (58%) patients with simple and N = 372 (42%) with complex appendicitis. Of the children aged 0-5 years, 81% had complex appendicitis, versus 38% in 6-18 years (p < 0.001). An overall decline was demonstrated for both simple and complex appendicitis between 2010 and 2019. No seasonal variation was found for simple appendicitis. For complex appendicitis, the highest number of patients was found in spring, and lowest in summer (N = 372, spring 28.2 ± 5.1% versus summer 21.0 ± 5.8%, p = 0.011), but the variance was regarded as not relevant (<5% from baseline). A positive correlation was found between complex appendicitis with Adenovirus 40.41 (R = 0.356, 95%CI 0.045-0.604, p = 0.026) and simple appendicitis with Adenovirus NON 40.41 (R = 0.332, 95%CI 0.019-0.586, p = 0.039), but these correlations did not remain significant after a Bonferroni correction (p < 0.003). In conclusion, we found no relevant seasonal variation for simple or complex appendicitis, nor positive correlation with common viral pathogens.

Crohn's Disease Mortality and Ambient Air Pollution in New York City

BACKGROUND

The worldwide increase in Crohn's disease (CD) has accelerated alongside rising urbanization and accompanying decline in air quality. Air pollution affects epithelial cell function, modulates immune responses, and changes the gut microbiome composition. In epidemiologic studies, ambient air pollution has a demonstrated relationship with incident CD and hospitalizations. However, no data exist on the association of CD-related death and air pollution.

METHODS

We conducted an ecologic study comparing the number of CD-related deaths of individuals residing in given zip codes, with the level of air pollution from nitric oxide, nitrogen dioxide, sulfur dioxide (SO2), and fine particulate matter. Air pollution was measured by the New York Community Air Survey. We conducted Pearson correlations and a Poisson regression with robust standard errors. Each pollution component was modeled separately.

RESULTS

There was a higher risk of CD-related death in zip codes with higher levels of SO2 (incidence rate ratio [IRR], 1.16; 95% confidence interval [CI], 1.06-1.27). Zip codes with higher percentage of Black or Latinx residents were associated with lower CD-related death rates in the SO2 model (IRR, 0.58; 95% CI, 0.35-0.98; and IRR, 0.13; 95% CI, 0.05-0.30, respectively). There was no significant association of either population density or area-based income with the CD-related death rate.

CONCLUSIONS

In New York City from 1993 to 2010, CD-related death rates were higher among individuals from neighborhoods with higher levels of SO2 but were not associated with levels of nitric oxide, nitrogen dioxide, and fine particulate matter. These findings raise an important and timely public health issue regarding exposure of CD patients to environmental SO2, warranting further exploration.

Particulate matter 10 exposure affects intestinal functionality in both inflamed 2D intestinal epithelial cell and 3D intestinal organoid models

Background

A growing body of evidence suggests that particulate matter (PM10) enters the gastrointestinal (GI) tract directly, causing the GI epithelial cells to function less efficiently, leading to inflammation and an imbalance in the gut microbiome. PM10 may, however, act as an exacerbation factor in patients with inflamed intestinal epithelium, which is associated with inflammatory bowel disease.

Objective

The purpose of this study was to dissect the pathology mechanism of PM10 exposure in inflamed intestines.

Methods

In this study, we established chronically inflamed intestinal epithelium models utilizing two-dimensional (2D) human intestinal epithelial cells (hIECs) and 3D human intestinal organoids (hIOs), which mimic in vivo cellular diversity and function, in order to examine the deleterious effects of PM10 in human intestine-like in vitro models.

Results

Inflamed 2D hIECs and 3D hIOs exhibited pathological features, such as inflammation, decreased intestinal markers, and defective epithelial barrier function. In addition, we found that PM10 exposure induced a more severe disturbance of peptide uptake in inflamed 2D hIECs and 3D hIOs than in control cells. This was due to the fact that it interferes with calcium signaling, protein digestion, and absorption pathways. The findings demonstrate that PM10-induced epithelial alterations contribute to the exacerbation of inflammatory disorders caused by the intestine.

Conclusions

According to our findings, 2D hIEC and 3D hIO models could be powerful in vitro platforms for the evaluation of the causal relationship between PM exposure and abnormal human intestinal functions.

Impact of air pollution on human health in different geographical locations of Nepal

According to a recent survey, Nepal's urban air quality has been classified as one of the worst in the globe. A large portion of the country's population is subjected to health risks caused by air pollution. As Nepal has a wide variation in altitude coupled with socio-cultural and biological diversities, it is important to understand the different health hazards in the different geographical regions - Terai, Hills and Mountains. Constantly increasing physical infrastructures (such as transport vehicles, open burning of plastics and other fuels) are the main reasons for the escalating air pollution in the country. This study aims to critically review the current air pollution status in different geographical locations along with its impacts on public health in the country. It has been revealed that irrespective of geographic location, the air pollutants interfere with different human physiological systems related to respiration as well as cardiovascular, ophthalmic, and gastrointestinal functioning. Further, the research findings highlighting the influence of prolonged exposure of the population to the air pollution leading to the significant number of deaths have been presented. A notable rise in the number of hospitalized patients suffering from illnesses related to above mentioned pollution borne cases has been reported.

Emerging epigenetic dynamics in gut-microglia brain axis: experimental and clinical implications for accelerated brain aging in schizophrenia

Brain aging, which involves a progressive loss of neuronal functions, has been reported to be premature in probands affected by schizophrenia (SCZ). Evidence shows that SCZ and accelerated aging are linked to changes in epigenetic clocks. Recent cross-sectional magnetic resonance imaging analyses have uncovered reduced brain reserves and connectivity in patients with SCZ compared to typically aging individuals. These data may indicate early abnormalities of neuronal function following cyto-architectural alterations in SCZ. The current mechanistic knowledge on brain aging, epigenetic changes, and their neuropsychiatric disease association remains incomplete. With this review, we explore and summarize evidence that the dynamics of gut-resident bacteria can modulate molecular brain function and contribute to age-related neurodegenerative disorders. It is known that environmental factors such as mode of birth, dietary habits, stress, pollution, and infections can modulate the microbiota system to regulate intrinsic neuronal activity and brain reserves through the vagus nerve and enteric nervous system. Microbiota-derived molecules can trigger continuous activation of the microglial sensome, groups of receptors and proteins that permit microglia to remodel the brain neurochemistry based on complex environmental activities. This remodeling causes aberrant brain plasticity as early as fetal developmental stages, and after the onset of first-episode psychosis. In the central nervous system, microglia, the resident immune surveillance cells, are involved in neurogenesis, phagocytosis of synapses and neurological dysfunction. Here, we review recent emerging experimental and clinical evidence regarding the gut-brain microglia axis involvement in SCZ pathology and etiology, the hypothesis of brain reserve and accelerated aging induced by dietary habits, stress, pollution, infections, and other factors. We also include in our review the possibilities and consequences of gut dysbiosis activities on microglial function and dysfunction, together with the effects of antipsychotics on the gut microbiome: therapeutic and adverse effects, role of fecal microbiota transplant and psychobiotics on microglial sensomes, brain reserves and SCZ-derived accelerated aging. We end the review with suggestions that may be applicable to the clinical setting. For example, we propose that psychobiotics might contribute to antipsychotic-induced therapeutic benefits or adverse effects, as well as reduce the aging process through the gut-brain microglia axis. Overall, we hope that this review will help increase the understanding of SCZ pathogenesis as related to chronobiology and the gut microbiome, as well as reveal new concepts that will serve as novel treatment targets for SCZ.

Sulfur dioxide may predominate in the adverse effects of ambient air pollutants on semen quality among the general population in Hefei, China

Previous studies have reported potential adverse effects of exposure to ambient air pollutants on semen quality in infertile men, but studies on the general population have been limited and inconsistent, and the pollutants that play a major role remain unclear. This study aimed to explore the potential association between exposure to six air pollutants (PM_2.5, PM₁₀, NO₂, SO₂, O₃ and CO) during different sperm development periods and semen quality among the general population, and to explore the interaction between different air pollutant exposures. We included 1515 semen samples collected from the Human Sperm Bank. We improved individuals' exposure level estimation by combining inverse distance weighting (IDW) interpolation with satellite remote sensing data. Multivariate linear regression models, restricted cubic spline functions and double-pollutant models were used to assess the relationship between exposure to six air pollutants and sperm volume, concentration, total sperm number and sperm motility. A negative association was found between SO₂ exposure and progressive motility and total motility during 0-90 lag days and 70-90 lag days, and SO₂ exposure during 10-14 lag days adversely affected sperm concentration and total sperm number. Sensitive analyses for qualified sperm donors and the double-pollutant models obtained similar results. Additionally, there were nonlinear relationships between exposure to PM, NO₂, O₃, CO and a few semen parameters, with NO₂ and O₃ exposure above the threshold showing negative correlations with total motility and progressive motility, respectively. Our study suggested that SO₂ may play a dominant role in the adverse effects of ambient air pollutants on semen quality in the general population by decreasing sperm motility, sperm concentration and total sperm number. Also, even SO₂ exposure lower than the recommended standards of the World Health Organization (WHO) could still cause male reproductive toxicity, which deserves attention.

Typical and Atypical Presentations of Appendicitis and Their Implications for Diagnosis and Treatment: A Literature Review

Appendicitis, an acute inflammation of the appendix, affects all demographic groups and exhibits various incidences and clinical manifestations. While acute appendicitis typically presents with colicky periumbilical abdominal pain that localizes to the right lower quadrant, atypical presentations are more common in children, geriatric, and pregnant patient populations, leading to delays in diagnosis. Clinical evaluation, clinical scoring systems, and inflammatory markers are commonly used, but their limitations have led to the increased use of diagnostic imaging in patients suspected of appendicitis. Acute appendicitis is managed by non-operative and operative management, depending on whether it is uncomplicated or complicated. Developing diagnostic pathways to improve outcomes and reduce complications is crucial. Although medical advancements have been made, diagnosing and managing appendicitis can be challenging, mainly when patients are present atypically. This literature review aims to comprehensively review typical and atypical presentations of appendicitis and their current implications for diagnosis and treatment modalities in pediatric, adult, pregnant, and geriatric patient populations.

Impacts of short-term air pollution exposure on appendicitis admissions: Evidence from one of the most polluted cities in mainland China

Background

Emerging evidence indicates that air pollutants contribute to the development and progression of gastrointestinal diseases. However, there is scarce evidence of an association with appendicitis in mainland China.

Methods

In this study, Linfen city, one of the most polluted cities in mainland China, was selected as the study site to explore whether air pollutants could affect appendicitis admissions and to identify susceptible populations. Daily data on appendicitis admissions and three principal air pollutants, including inhalable particulate matter (PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2) were collected in Linfen, China. The impacts of air pollutants on appendicitis were studied by using a generalized additive model (GAM) combined with the quasi-Poisson function. Stratified analyses were also performed by sex, age, and season.

Results

We observed a positive association between air pollution and appendicitis admissions. For a 10 μg/m3 increase in pollutants at lag01, the corresponding relative risks (RRs) and 95% confidence intervals (95% CIs) were 1.0179 (1.0129–1.0230) for PM10, 1.0236 (1.0184–1.0288) for SO2, and 1.0979 (1.0704–1.1262) for NO2. Males and people aged 21–39 years were more susceptible to air pollutants. Regarding seasons, the effects seemed to be stronger during the cold season, but there was no statistically significant difference between the seasonal groups.

Conclusions

Our findings indicated that short-term air pollution exposure was significantly correlated with appendicitis admissions, and active air pollution interventions should be implemented to reduce appendicitis hospitalizations, especially for males and people aged 21–39 years.

Gastrointestinal health: changes of intestinal mucosa and microbiota in patients with ulcerative colitis and irritable bowel syndrome from PM2.5-polluted regions of Ukraine

Here, clinical studies of patients were conducted to assess changes in patients with ulcerative colitis (UC) and irritable bowel syndrome (IBS) associated with air pollution by PM. A comparative study of 100 patients with UC and 75 with IBS from highly (HPRs) and low (LPRs) PM_2.5-polluted regions of Ukraine was conducted. Biopsy of the intestinal mucosa of patients with UC from HPRs showed severe cellular infiltration. Patients with IBS from HPRs had changes in the superficial epithelium (focal desquamation), and inflammatory-cellular infiltration of mucous membrane of the colon. In patients with UC, changes in mucus production were found, which were more significant in HPR patients. PAS response did not depend on the residence; the level of MUC2 was significantly lower in HPR patients with UC (1.12 vs 2.15 au). In patients with UC from HPRs, a decrease in Bacteroidetes (34.0 vs. 39.0 small intestinal bacterial overgrowth (SIBO), ppm) and an increase in Proteobacteria compared to LPRs were shown. In IBS patients, significant differences were found in the level of Proteobacteria, which was higher in HPRs. The level of regulatory flora Akkermansia muciniphila and Faecalibacterium prausnitzii reduced in patients with UC from HPRs. In patients from LPRs, the level of Akkermansia muciniphila raised above normal (2.8 vs 4.7 SIBO, ppm). Similar changes of regulatory flora have been identified in patients with IBS from different regions. Therefore, a more severe course of the disease (more pronounced cellular infiltration and violation of the microbiota) was shown in patients with UC from HPRs as compared to LPRs.

Association of Appendicitis Incidence With Warmer Weather Independent of Season

IMPORTANCE

Acute appendicitis is a common cause of abdominal pain and the most common reason for emergency surgery in several countries. Increased cases during summer months have been reported.

OBJECTIVE

To investigate the incidence of acute appendicitis by considering local temperature patterns in geographic regions with different climate over several years.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used insurance claims data from the MarketScan Commercial Claims and Encounters Database and the Medicare Supplemental and Coordination of Benefits Database from January 1, 2001, to December 31, 2017. The cohort included individuals at risk for appendicitis who were enrolled in US insurance plans that contribute data to the MarketScan databases. Cases of appendicitis in the inpatient, outpatient, and emergency department settings were identified using International Classification of Diseases, Ninth Revision, Clinical Modification or International Statistical Classification of Diseases, Tenth Revision, Clinical Modification diagnosis codes. Local weather data were obtained for individuals living in a metropolitan statistical area (MSA) from the Integrated Surface Database. Associations were characterized using a fixed-effects generalized linear model based on a negative binomial distribution. The model was adjusted for age, sex, and day of week and included fixed effects for year and MSA. The generalized linear model was fit with a piecewise linear model by searching each 0.56 °C in temperature for change points. To further isolate the role of temperature, observed temperature was replaced with the expected temperature and the deviation of the observed temperature from the expected temperature for a given city on a given day of year. Data were analyzed from October 1, 2021, to July 31, 2022.

MAIN OUTCOMES AND MEASURES

The primary outcome was the daily number of appendicitis cases in a given city stratified by age and sex, with mean temperature in the MSA over the previous 7 days as the independent variable.

RESULTS

A total of 450 723 744 person-years at risk and 689 917 patients with appendicitis (mean [SD] age, 35 [18] years; 347 473 male [50.4%] individuals) were included. Every 5.56 °C increase in temperature was associated with a 1.3% increase in the incidence of appendicitis (incidence rate ratio [IRR], 1.01; 95% CI, 1.01-1.02) when temperatures were 10.56 °C or lower and a 2.9% increase in incidence (IRR, 1.03; 95% CI, 1.03-1.03) for temperatures higher than 10.56 °C. In terms of temperature deviations, a higher-than-expected temperature increase greater than 5.56 °C was associated with a 3.3% (95% CI, 1.0%-5.7%) increase in the incidence of appendicitis compared with days with near-0 deviations.

CONCLUSIONS AND RELEVANCE

Results of this cohort study observed seasonality in the incidence of appendicitis and found an association between increased incidence and warmer weather. These results could help elucidate the mechanism of appendicitis.

Is higher ambient temperature associated with acute appendicitis hospitalizations? A case-crossover study in Tongling, China

Existing studies suggested that ambient temperature may affect the attack of acute appendicitis. However, the identification of the quantitative effect and vulnerable populations are still unknown. The purposes of this study were to quantify the impact of daily mean temperature on the hospitalization of acute appendicitis and clarify vulnerable groups, further guide targeted prevention of acute appendicitis in Tongling. Daily data of cases and meteorological factors were collected in Tongling, China, during 2015-2019. Time stratified case-crossover design and conditional logistic regression model were used to evaluate the odds ratio (OR) of ambient temperature on hospitalizations for acute appendicitis. Stratified analyses were performed by sex, age, and marital status. The odds ratio (OR) of hospitalizations for acute appendicitis increased by 1.6% for per 1 ℃ rise in mean temperature at lag3[OR = 1.016, 95% confidence interval (CI): 1.004-1.028]. In addition, our results suggest it is in the women that increased ambient temperature is more likely to contribute to acute appendicitis hospitalizations; we also found that the married are more susceptible to acute appendicitis hospitalizations due to increased ambient temperature than the unmarried; people in the 21-40 years old are more sensitive to ambient temperature than other age groups. The significant results of the differences between the subgroups indicate that the differences between the groups are all statistically significant. The elevated ambient temperatures increased the risk of hospitalizations for acute appendicitis. The females, married people, and patients aged 21-40 years old were more susceptible to ambient temperature. These findings suggest that more attention should be paid to the impact of high ambient temperature on acute appendicitis in the future.

Long-term exposure to air pollution and risk of incident inflammatory bowel disease among middle and old aged adults

BACKGROUND

Epidemiological evidence regarding the associations between long-term exposure to air pollution and risk of incident inflammatory bowel disease (IBD) is scant.

OBJECTIVES

We examined the associations of various specific air pollutants with the risk of incident ulcerative colitis and Crohn's disease, two subtypes of IBD, among middle and old aged adults in the UK. We also explored potential susceptible subgroups.

METHODS

We used data from the UK Biobank study. Information on air pollution, including PM_2.5, PM_2.5-10, PM₁₀ as well as NO₂ and NO_x were estimated using the Land Use Regression model. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 11.7 years, 1872 incident ulcerative colitis and 865 incident Crohn's disease cases were identified among 455,210 IBD-free participants. HRs (95% CIs) of ulcerative colitis associated with each 1 interquartile range (IQR) increase in PM_2.5, PM_2.5-10, PM₁₀, NO₂, and NO_x were 1.06 (1.01, 1.12), 1.03 (0.99, 1.08), 1.09 (1.03, 1.16), 1.12 (1.07, 1.19), and 1.07 (1.02, 1.12), respectively. The associations between all the air pollutants and risk of Crohn's disease were null. Smoking status and sex appeared to respectively modify the associations between some air pollutants and risk of ulcerative colitis and Crohn's disease.

CONCLUSION

Long-term exposure to various air pollutants was associated with the risk of incident ulcerative colitis but not Crohn's disease, highlighting the importance of developing environmental health strategy to reduce the burden of ulcerative colitis.

Probiotics, prebiotics, and synbiotics to prevent or combat air pollution consequences: The gut-lung axis

Air pollution exposure is a public health emergency, which attributes globally to an estimated seven million deaths on a yearly basis We are all exposed to air pollutants, varying from ambient air pollution hanging over cities to dust inside the home. It is a mixture of airborne particulate matter and gases that can be subdivided into three categories based on particle diameter. The smallest category called PM_0.1 is the most abundant. A fraction of the particles included in this category might enter the blood stream spreading to other parts of the body. As air pollutants can enter the body via the lungs and gut, growing evidence links its exposure to gastrointestinal and respiratory impairments and diseases, like asthma, rhinitis, respiratory tract infections, Crohn's disease, ulcerative colitis, and abdominal pain. It has become evident that there exists a crosstalk between the respiratory and gastrointestinal tracts, commonly referred to as the gut-lung axis. Via microbial secretions, metabolites, immune mediators and lipid profiles, these two separate organ systems can influence each other. Well-known immunomodulators and gut health stimulators are probiotics, prebiotics, together called synbiotics. They might combat air pollution-induced systemic inflammation and oxidative stress by optimizing the microbiota composition and microbial metabolites, thereby stimulating anti-inflammatory pathways and strengthening mucosal and epithelial barriers. Although clinical studies investigating the role of probiotics, prebiotics, and synbiotics in an air pollution setting are lacking, these interventions show promising health promoting effects by affecting the gastrointestinal- and respiratory tract. This review summarizes the current data on how air pollution can affect the gut-lung axis and might impact gut and lung health. It will further elaborate on the potential role of probiotics, prebiotics and synbiotics on the gut-lung axis, and gut and lung health.

Short-term effects of ambient air pollution on daily emergency room visits for abdominal pain: a time-series study in Wuhan, China

Short-term exposure to ambient air pollution has been proven to result in respiratory, cardiovascular, and digestive diseases, leading to increased emergency room visits (ERVs). Abdominal pain complaints provide a large proportion of the ERVs, as yet few studies have focused on the correlations between ambient air pollution and abdominal pain, especially in emergency departments within China. Daily data for daily ERVs were collected in Wuhan, China (from January 1, 2016 to December 31, 2018), including air pollution concentration (SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃), and meteorological variables. We conducted a time-series study to investigate the potential correlation between six ambient air pollutants and ERVs for abdominal pain and their effects, in different genders, ages, and seasons. A total of 16,318 abdominal pain ERVs were identified during the study period. A 10-μg/m³ increase in concentration of SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃ corresponded respectively to incremental increases in abdominal pain of 4.89% (95% confidence interval [CI]: - 1.50-11.70), 1.85% (95% CI: - 0.29-4.03), 0.83% (95% CI: - 0.05-1.72), - 0.22% (95% CI: - 0.73-0.30), 0.24% (95% CI: 0.08-0.40), and 0.86% (95% CI: 0.04 - 1.69). We observed significant correlations between CO and O₃ and increases in daily abdominal pain ERVs and positive but insignificant correlations between the other pollutants and ERVs (except PM₁₀). The effects were stronger for females (especially SO₂ and O₃: 13.53% vs. - 2.46%; 1.20% vs. 0.47%, respectively) and younger people (especially CO and O_3: 0.25% vs. 0.01%; 1.36% vs. 0.15%, respectively). Males (1.38% vs. 0.87%) and elders (1.27% vs. 0.99%) were more likely to be affected by PM_2.5. The correlations with PM_2.5 were stronger in cool seasons (1.25% vs. - 0.07%) while the correlation with CO was stronger in warm seasons (0.47% vs. 0.14%). Our time-series study suggests that short-term exposure to air pollution (especially CO and O₃) was positively correlated with ERVs for abdominal pain in Wuhan, China, and that the effects varied by season, gender and age. These data can add evidence on how air pollutants affect the human body and may prompt hospitals to take specific precautions on polluted days and maintain order in emergency departments made busier due to the pollution.

A randomization-based causal inference framework for uncovering environmental exposure effects on human gut microbiota

Statistical analysis of microbial genomic data within epidemiological cohort studies holds the promise to assess the influence of environmental exposures on both the host and the host-associated microbiome. However, the observational character of prospective cohort data and the intricate characteristics of microbiome data make it challenging to discover causal associations between environment and microbiome. Here, we introduce a causal inference framework based on the Rubin Causal Model that can help scientists to investigate such environment-host microbiome relationships, to capitalize on existing, possibly powerful, test statistics, and test plausible sharp null hypotheses. Using data from the German KORA cohort study, we illustrate our framework by designing two hypothetical randomized experiments with interventions of (i) air pollution reduction and (ii) smoking prevention. We study the effects of these interventions on the human gut microbiome by testing shifts in microbial diversity, changes in individual microbial abundances, and microbial network wiring between groups of matched subjects via randomization-based inference. In the smoking prevention scenario, we identify a small interconnected group of taxa worth further scrutiny, including Christensenellaceae and Ruminococcaceae genera, that have been previously associated with blood metabolite changes. These findings demonstrate that our framework may uncover potentially causal links between environmental exposure and the gut microbiome from observational data. We anticipate the present statistical framework to be a good starting point for further discoveries on the role of the gut microbiome in environmental health.

Environmental influences on the human gut microbiome are still to be discovered or better understood. In this paper, we contribute to the field of microbiome research and environmental epidemiology by suggesting a stage-based causal inference framework relying on the foundations of the Rubin Causal Model. A particularity of the framework is the use of randomization-based inference, which we value to be a necessary exploratory inference method when tackling untapped research questions. To illustrate the framework, we explore the effects of two inhaled environmental exposures previously hypothesized to be linked with gastrointestinal diseases and the gut microbiome: air pollution exposure and cigarette smoking.

Building sustainable and resilient surgical systems: A narrative review of opportunities to integrate climate change into national surgical planning in the Western Pacific region

Five billion people lack access to surgical care worldwide; climate change is the biggest threat to human health in the 21st century. This review studies how climate change could be integrated into national surgical planning in the Western Pacific region. We searched databases (PubMed, Web of Science, and Global Health) for articles on climate change and surgical care. Findings were categorised using the modified World Health Organisation Health System Building Blocks Framework. 220 out of 2577 records were included. Infrastructure: Operating theatres are highly resource-intensive. Their carbon footprint could be reduced by maximising equipment longevity, improving energy efficiency, and renewable energy use. Service delivery Tele-medicine, outreaches, and avoiding desflurane could reduce emissions. Robust surgical systems are required to adapt to the increasing burden of surgically treated diseases, such as injuries from natural disasters. Finance: Climate change adaptation funds could be mobilised for surgical system strengthening. Information systems: Sustainability should be a key performance indicator for surgical systems. Workforce: Surgical providers could change clinical, institutional, and societal practices. Governance: Planning in surgical care and climate change should be aligned. Climate change mitigation is essential in the regional surgical care scale-up; surgical system strengthening is also necessary for adaptation to climate change.

Probiotics Function as Immunomodulators in the Intestine in C57Bl/6 Male Mice Exposed to Inhaled Diesel Exhaust Particles on a High-Fat Diet

Epidemiological studies reveal a correlation between air pollution exposure and gastrointestinal (GI) diseases, yet few studies have investigated the role of inhaled particulate matter on intestinal integrity in conjunction with a high-fat (HF) diet. Additionally, there is currently limited information on probiotics in mitigating air-pollutant responses in the intestines. Thus, we investigated the hypothesis that exposure to inhaled diesel exhaust particles (DEP) and a HF diet can alter intestinal integrity and inflammation, which can be attenuated with probiotics. 4-6-w-old male C57Bl/6 mice on a HF diet (45% kcal fat) were randomly assigned to be exposed via oropharyngeal aspiration to 35 µg of DEP suspended in 35 µL of 0.9% sterile saline or sterile saline (CON) only twice a week for 4 w. A subset of mice was treated with 0.3 g/day of Winclove Ecologic^® barrier probiotics (PRO) in drinking water throughout the duration of the study. Our results show that DEP exposure ± probiotics resulted in increased goblet cells and mucin (MUC)-2 expression, as determined by AB/PAS staining. Immunofluorescent quantification and/or RT-qPCR showed that DEP exposure increases claudin-3, occludin, zona occludens (ZO)-1, matrix metalloproteinase (MMP)-9, and toll-like receptor (TLR)-4, and decreases tumor necrosis factor (TNF)-α and interleukin (IL)-10 expression compared to CON. DEP exposure + probiotics increases expression of claudin-3, occludin, ZO-1, TNF-α, and IL-10 and decreases MMP-9 and TLR-4 compared to CON + PRO in the small intestine. Collectively, these results show that DEP exposure alters intestinal integrity and inflammation in conjunction with a HF diet. Probiotics proved fundamental in understanding the role of the microbiome in protecting and altering inflammatory responses in the intestines following exposure to inhaled DEP.

Insight into Inflammatory Bowel Disease Pathogenesis: Is the Answer Blowing in the Wind?

Inflammatory bowel diseases (IBD) including Crohn's disease and ulcerative colitis are conditions characterized by immune dysregulation to a trigger in those with a genetic predisposition. Environmental factors are thought to contribute to IBD, but no definite trigger has been identified. Aeroallergens have not been thoroughly investigated in their potential contribution to the pathogenesis to IBD. The geographic distribution of aeroallergens and IBD, the association of atopic disease with IBD, seasonality and IBD, and cross-reactive food allergens require further study with implications for targeted dietary and immunomodulatory therapies.

Cold Climate Impact on Air-Pollution-Related Health Outcomes: A Scoping Review

In cold temperatures, vehicles idle more, have high cold-start emissions including greenhouse gases, and have less effective exhaust filtration systems, which can cause up to ten-fold more harmful vehicular emissions. Only a few vehicle technologies have been tested for emissions below -7 °C (20 °F). Four-hundred-million people living in cities with sub-zero temperatures may be impacted. We conducted a scoping review to identify the existing knowledge about air-pollution-related health outcomes in a cold climate, and pinpoint any research gaps. Of 1019 papers identified, 76 were selected for review. The papers described short-term health impacts associated with air pollutants. However, most papers removed the possible direct effect of temperature on pollution and health by adjusting for temperature. Only eight papers formally explored the modifying effect of temperatures. Five studies identified how extreme cold and warm temperatures aggravated mortality/morbidity associated with ozone, particles, and carbon-monoxide. The other three found no health associations with tested pollutants and temperature. Additionally, in most papers, emissions could not be attributed solely to traffic. In conclusion, evidence on the relationship between cold temperatures, traffic-related pollution, and related health outcomes is lacking. Therefore, targeted research is required to guide vehicle regulations, assess extreme weather-related risks in the context of climate change, and inform public health interventions.

Volcanic ash-driven worsening of mucosal inflammation in an experimental colitis model

Particulate matter exposure and related chemical changes in drinking water have been associated with health problems and inflammatory disorders. This study aimed to examine the effect of orally administered ash-water dilution on the gut of mice under normal and inflammatory conditions. Balb/c mice received ash-released soluble and dust-suspended components in the drinking water for 14 days. On day 7, animals were intrarectally instilled with TNBS in ethanol or flagellin from Salmonella typhimurium in PBS. At sacrifice, colon segments were collected and histologic damage, mRNA expression and cytokine levels in tissue were evaluated. In addition, these parameters were also evaluated in IL-10 null mice. We found that mice that received 5% w. fine-ash dilution in the drinking water worsened colitis signs. Weight loss, shortening of the colon, tissue edema with mucosa and submucosa cell infiltration and production of pro-inflammatory cytokines and chemokines were enhanced compared to control mice. A more pronounced inflammation was observed in IL-10 null mice. In addition, markers of NLRP3-dependent inflammasome activation were found in animals exposed to ash. In conclusion, ingestion of contaminated water with dust-suspended particulate matter enhanced the inflammatory response in the gut, probably due to alteration of the gut barrier and promoting an intense contact with the luminal content. This study critically appraises the response for fine particulate matter in uncommon illnesses reported for volcanic ash pollution. We suggest actions to enable better prediction and assessment the health impacts of volcanic eruptions.

Clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis: 19 cases (2015-2019)

OBJECTIVE

To report clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis.

ANIMALS

19 rabbits.

PROCEDURES

Medical records for client-owned rabbits that had a histologic diagnosis of appendicitis were reviewed.

RESULTS

Median age of the rabbits at presentation was 24.0 months (range, 4 to 84 months). Seventeen cases occurred during the summer and fall seasons. Decreased appetite (17/19 rabbits), abnormal rectal temperature (hyperthermia, 9/16 rabbits; hypothermia, 4/16 rabbits), hypocalcemia (8/11 rabbits), and hypoglycemia (7/15 rabbits) were common signs. Abdominal ultrasonography and CT findings were suggestive of appendicitis in 6 of 8 rabbits and in 1 of 2 rabbits, respectively. Of the 6 rabbits that received medical treatment, 3 died at 48 hours, 1 died at 24 hours after hospitalization, and 1 died at 10 days after presentation; 1 rabbit was alive at 1,030 days after presentation. Of the 8 rabbits that underwent appendectomy, 3 died before discharge from the hospital and 1 died 113 days after surgery; 4 rabbits were alive at 315, 334, 1,433, and 1,473 days after presentation. The remaining 5 rabbits either died or were euthanized before treatment could be instituted. In each of the 19 rabbits, the appendix had evidence of severe inflammation with mucosal ulceration, heterophilic inflammation, and necrotic debris.

CLINICAL RELEVANCE

For rabbits with decreased appetite and an apparently painful abdomen, hyperthermia, hypocalcemia, or hypoglycemia, appendicitis should be considered as a differential diagnosis. Further comparisons of medical and surgical treatments are required to establish treatment recommendations for rabbits with appendicitis.

The SARS-CoV-2 first wave impact in the acute inflammatory surgical pathologies

Anecdotal evidence suggests that community infection control measures during the COVID-19 outbreak have modified the number and natural history of acute surgical inflammatory processes (ASIP—appendicitis, cholecystitis, diverticulitis and perianal abscesses) admissions. This study aims to evaluate the impact of the COVID-19 pandemic on the presentation and treatment ASIP and quantify the effect of COVID-19 infection on the outcomes of ASIP patients. This was a multicentre, comparative study, whereby ASIP cases from 2019, 2020 and 2021 (March 14th to May 2nd) were analyzed. Data regarding patient and disease characteristics as well as outcomes, were collected from sixteen centres in Madrid, and one in Seville (Spain). The number of patients treated for ASIP in 2019 was 822 compared to 521 in 2020 and 835 in 2021. This 1/3rd reduction occurs mainly in patients with mild cases, while the number of severe cases was similar. Surgical standards suffered a step back during the first wave: Lower laparoscopic approach and longer length of stay. We also found a more conservative approach to the patients this year, non-justified by clinical circumstances. Luckily these standards improved again in 2021. The positive COVID-19 status itself did not have a direct impact on mortality. Strikingly, none of the 33 surgically treated COVID positive patients during both years died postoperatively. This is an interesting finding which, if confirmed through future research with a larger sample size of COVID-19 positive patients, can expedite the recovery phase of acute surgical services.

Seasonal variation of acute appendicitis: An Armed Forces experience of high altitude

Background

Lifetime prevalence of Acute Appendicitis is about 6-7%.The seasonal variation is nearly an established fact with most of the studies suggesting that cases are more in summer and during the rainy season. There are few studies globally for evaluating the impact of altitude and temperature on the incidence of acute appendicitis. In India no such study has been reported. With this in view, a study was conducted on the incidence of acute appendicitis to evaluate the effect of absolute temperature in high altitudes >10000 ft.

Methods

Retrospective data collected for a period of five years from 2015 to 2019 for the three centres of Armed Forces, located at high altitude 10,500, 11,500 and 12,000 ft respectively and the three temperature categories viz.< 0 °C, 0-20 °C and >20 °C were made to infer if there is any correlation between these parameters.

Results

A total of 317 cases were operated in a period of 05 yrs at the three centres. In the three categories of temperature viz < 0 °C, 0-20 °C and >20 °C the total number of cases were 84,124 and 109 respectively over period of 5 yrs. The proportion of cases were maximum at altitude of 12000 ft. On evaluation of the effect of altitude and absolute temperature positive correlation is found.

Conclusion

The analysis of the maiden study that was conducted for high altitude and extreme cold climate in India indicated a positive correlation of the altitude and the effect of absolute temperature on the occurrence of cases of Acute Appendicitis.

A population-based analysis of the impact of the COVID-19 pandemic on common abdominal and gynecological emergency department visits

BACKGROUND

Reduced use of the emergency department during the COVID-19 pandemic may result in increased disease acuity when patients do seek health care services. We sought to evaluate emergency department visits for common abdominal and gynecologic conditions before and at the beginning of the pandemic to determine whether changes in emergency department attendance had serious consequences for patients.

METHODS

We conducted a population-based analysis using administrative data to evaluate the weekly rate of emergency department visits pre-COVID-19 (Jan. 1-Mar. 10, 2020) and during the beginning of the COVID-19 pandemic (Mar. 11-June 30, 2020), compared with a historical control period (Jan. 1-July 1, 2019). All residents of Ontario, Canada, presenting to the emergency department with appendicitis, cholecystitis, ectopic pregnancy or miscarriage were included. We evaluated weekly incidence rate ratios (IRRs) of emergency department visits, management strategies and clinical outcomes.

RESULTS

Across all study periods, 39 691 emergency department visits met inclusion criteria (40.2 % appendicitis, 32.1% miscarriage, 21.3% cholecystitis, 6.4% ectopic pregnancy). Baseline characteristics of patients presenting to the emergency department did not vary across study periods. After an initial reduction in emergency department visits, presentations for cholecystitis and ectopic pregnancy quickly returned to expected levels. However, presentations for appendicitis and miscarriage showed sustained reductions (IRR 0.61-0.80), with 1087 and 984 fewer visits, respectively, after the start of the pandemic, relative to 2019. Management strategies, complications and mortality rates were similar across study periods for all conditions.

INTERPRETATION

Although our study showed evidence of emergency department avoidance in Ontario during the first wave of the COVID-19 pandemic, no adverse consequences were evident. Emergency care and outcomes for patients were similar before and during the pandemic.

Association between short-term exposure to fine particulate pollution and outpatient visits for ulcerative colitis in Beijing, China: A time-series study

Environmental factors play an important role in the development of ulcerative colitis (UC). However, only few studies have examined the effects of air pollution on UC occurrence. We conducted a time-series analysis to explore the association between short-term exposure to fine particulate matter (PM_2.5) and outpatient visits for UC in Beijing, China. In total, 84,000 outpatient visits for UC were retrieved from the Beijing Medical Claim Data for Employees between January 1, 2010 and June 30, 2012. Measurements of daily PM_2.5 concentrations were obtained from the United States Embassy air-monitoring station. A generalized additive model with quasi-Poisson link was applied to examine the association between PM_2.5 concentrations and outpatient visits for UC stratified by sex, age, and season. We found that short-term exposure to PM_2.5 was significantly associated with increased daily outpatient visits for UC at lag 0 day. A 10 μg/m³ increase in PM_2.5 concentration at lag 0 day corresponded to a 0.32% increase in outpatient visits for UC (95% confidence interval (CI), 0.05-0.58%; P = 0.019). There was a clear concentration-response association between daily outpatient visits for UC and PM_2.5 concentrations. The PM_2.5 effects were significant across all sex and season subgroups, without evidence of effect modification by sex (P = 0.942) or season (P = 0.399). The association was positive in patients younger than 65 years old but negative in those 65 years old or older, although the difference was not significant (P = 0.883). In conclusion, our study demonstrated that short-term exposure to ambient PM_2.5 was significantly associated with an increased risk of daily outpatient visits for UC, especially in younger people. Additional studies are warranted to confirm our findings.

Seasonal Variation in Cases of Acute Appendicitis

Objectives

To investigate whether the incidence of acute appendicitis increases in summer and whether complicated cases present more in summer.

Methods

A single-center cross-sectional, retrospective study on 697 cases of appendicitis admitted in the year 2018. Inclusion criteria: patients admitted with acute appendicitis who underwent appendectomy of all ages. Exclusion criteria: conservative management. Analysis was performed using Microsoft Excel. Pearson correlation coefficient was calculated to assess the correlation between monthly incidence of appendicitis and mean temperature in that month.

Results

Fifty-one patients who were managed conservatively were excluded. Accordingly, 646 patients were included. Ages ranged from three to 77 years. Males comprised the majority (500, 77.4%). Gangrenous, perforated, and purulent appendices were regarded as complicated appendicitis. The highest number of cases were admitted in summer (234), comprising 36.2% of cases. Complicated cases were equal to 65, of which 23 (35.4%) were admitted in summer and 30 (46.2%) in winter. The highest number of cases was during the month of July (68), while the lowest (40) was during February. This corresponded to the highest recorded mean temperature (36.2°C) and second lowest (19.8°C), respectively. Moderate positive correlation (Pearson's R 0.5183) between the monthly incidence of appendicitis and the mean temperature is noted.

Conclusion

More cases of appendicitis were noted during summer. Monthly incidence correlated positively with the temperature. Larger numbers over several years are needed to draw better conclusions and reach the possible causes behind such variation.

Subchronic exposure to concentrated ambient PM2.5 perturbs gut and lung microbiota as well as metabolic profiles in mice

Exposure to ambient fine particular matter (PM2.5) are linked to an increased risk of metabolic disorders, leading to enhanced rate of many diseases, such as inflammatory bowel disease (IBD), cardiovascular diseases, and pulmonary diseases; nevertheless, the underlying mechanisms remain poorly understood. In this study, BALB/c mice were exposed to filtered air (FA) or concentrated ambient PM2.5 (CPM) for 2 months using a versatile aerosol concentration enrichment system(VACES). We found subchronic CPM exposure caused significant lung and intestinal damage, as well as systemic inflammatory reactions. In addition, serum and BALFs (bronchoalveolar lavage fluids) metabolites involved in many metabolic pathways in the CPM exposed mice were markedly disrupted upon PM2.5 exposure. Five metabolites (glutamate, glutamine, formate, pyruvate and lactate) with excellent discriminatory power (AUC = 1, p < 0.001) were identified to predict PM2.5 exposure related toxicities. Furthermore, subchronic exposure to CPM not only significantly decreased the richness and composition of the gut microbiota, but also the lung microbiota. Strong associations were found between several gut and lung bacterial flora changes and systemic metabolic abnormalities. Our study showed exposure to ambient PM2.5 not only caused dysbiosis in the gut and lung, but also significant systemic and local metabolic alterations. Alterations in gut and lung microbiota were strongly correlated with metabolic abnormalities. Our study suggests potential roles of gut and lung microbiota in PM2.5 caused metabolic disorders.

Review article: Epidemiological and animal evidence for the role of air pollution in intestinal diseases

BACKGROUND

Ambient air pollution is recognized as one of the leading causes of global burden of disease. Involvement of air pollution in respiratory and cardiovascular diseases was first recognized, and then cumulative data has indicated that the intestinal tract could be also damaged.

AIM

To review and discuss the current epidemiological and animal data on the effects of air pollution on intestinal homeostasis.

METHODS

An extensive literature search was conducted using Google Scholar and Pubmed to gather relevant human and animal studies that have reported the effects of any air pollutant on the intestine.

RESULTS

Exposure to several gaseous and particulate matter components of air pollution have been associated either positively or negatively with the onset of various intestinal diseases including appendicitis, gastroenteric disorders, irritable bowel syndrome, inflammatory bowel diseases, and peptic ulcers. Several atmospheric pollutants have been associated with modifications of gut microbiota in humans. Animal studies have showed that inhalation of atmospheric particulate matter can lead to modifications of gut microbiota, impairments of oxidative and inflammatory intestinal balances, and disruption of gut epithelial permeability.

CONCLUSIONS

Overall, the literature appears to indicate that the gut is an underestimated target of adverse health effects induced by air pollution. It is therefore important to develop additional studies that aim to better understand the link between air pollutants and gastro-intestinal diseases.

Effect of ambient air pollution on the incidence of colorectal cancer among a diabetic population: a nationwide nested case-control study in Taiwan

OBJECTIVES

An increasing number of studies had shown that air pollution exposure may aggravate blood glucose control in patients with diabetes, an independent risk factor for colorectal cancer (CRC) proposed by some researchers. This study aimed to investigate the impact of exposure to ambient particulate matter with aerodynamic diameters ≤2.5 μm (PM_2.5) on the incidence of CRC among a diabetic population.

DESIGN

A nested case-control study.

SETTING

A subset data retrieved from the Taiwan's National Health Insurance Research Database.

PARTICIPANTS

We identified patients with newly diagnosed diabetes (n=1 164 962) during 1999-2013. Participants who had subsequently developed an incident of CRC were placed into the case group, while controls were matched to the cases at a 4:1 ratio by age, gender, date of diabetes diagnosis and the index date of CRC diagnosis.

METHODS AND OUTCOME MEASURES

All variables associated with the risk of CRC entered into a multinomial logistic regression model. The dose-response relationship between various average concentrations of PM_2.5 exposure and the incidence of CRC was estimated by logistic regression.

RESULTS

The study included a total of 7719 incident CRC cases matched with 30 876 controls of random sampling. The mean annual concentration of PM_2.5 was 35.3 µg/m³. After adjusting for potential confounders, a dose-response relationship was observed between the CRC risks and each interquartile increase of PM_2.5 concentration (Q1-Q2: 1.03 (0.95-1.11), Q2-Q3: 1.06 (0.98-1.15), ≥Q3: 1.19 (1.10-1.28) in model 2. The adjusted ORs (95% CI) of CRC incidence for each 10 µg/m³ increment of PM_2.5 was 1.08 (1.04-1.11). Moreover, a faster growing adapted Diabetes Complications Severity Index (aDCSI) score was noticed in CRC group compared with the controls, which also showed a significant association in our multivariate analysis (adjusted OR=1.28, 95% CI 1.18 to 1.38).

CONCLUSIONS

Long-term exposure to high concentrations of PM_2.5 may contribute to an increased incidence of CRC among diabetic populations.

Temporal and spatial effect of air pollution on hospital admissions for myocardial infarction: a case-crossover study

BACKGROUND

In studies showing associations between ambient air pollution and myocardial infarction (MI), data have been lacking on the inherent spatial variability of air pollution. The aim of this study was to determine whether the long-term spatial distribution of air pollution influences short-term temporal associations between air pollution and admission to hospital for MI.

METHODS

We identified adults living in Calgary who were admitted to hospital for an MI between 2004 and 2012. We evaluated associations between short-term exposure to air pollution (ozone [O₃], nitrogen dioxide [NO₂], sulfur dioxide [SO₂], carbon monoxide [CO], particulate matter < 10 μm in diameter [PM₁₀] and particulate matter < 2.5 μm in diameter [PM_2.5]), and hospital admissions for MI using a time-stratified, case-crossover study design. Air Quality Health Index (AQHI) scores were calculated from a composition of O₃, NO₂ and PM_2.5. Conditional logistic regression models were stratified by low, medium and high levels of neighbourhood NO₂ concentrations derived from land use regression models; results of these analyses are presented as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

From 2004 to 2012, 6142 MIs were recorded in Calgary. Individuals living in neighbourhoods with higher long-term air pollution concentrations were more likely to be admitted to hospital for MI after short-term elevations in air pollution (e.g., 5-day average NO₂: OR 1.20, 95% CI 1.03-1.40, per interquartile range [IQR]) as compared with regions with lower air pollution (e.g., 5-day average NO₂: OR 0.90, 95% CI 0.78-1.04, per IQR). In high NO₂ tertiles, the AQHI score was associated with MI (e.g., 5-day average OR 1.13, 95% CI 1.02-1.24, per IQR; 3-day average OR 1.13, 95% CI 1.04-1.23, per IQR).

INTERPRETATION

Our results show that the effect of air pollution on hospital admissions for MI was stronger in areas with higher NO₂ concentrations than that in areas with lower NO₂ concentrations. Individuals living in neighbourhoods with higher traffic-related pollution should be advised of the health risks and be attentive to special air quality warnings.

Exposure to air pollutants and the gut microbiota: a potential link between exposure, obesity, and type 2 diabetes

Work has shown that increased exposure to air pollutants independently contributes to obesity and type 2 diabetes risk, yet the exact mechanisms underlying these associations have not been fully characterized. The current review summarizes recent findings regarding the impact of inhaled and ingested air pollutants on the gut microbiota. Animal and human studies provide evidence that air pollutants, such as particulate matter, nitrogen oxides, and ozone, have the potential to alter the gut microbiota. Further, studies suggest that such exposure-induced alterations to the gut microbiota may contribute to increased risk for obesity and type 2 diabetes through inflammatory pathways. Future work is needed to fully understand the complex interactions between air pollution, the gut microbiome, and human health. Additionally, advanced sequencing methods for gut microbiome research present unique opportunities to study the underlying pathways that link increased air pollution exposure with obesity and type 2 diabetes risk.

Blueberry Extracts as a Novel Approach to Prevent Ozone-Induced Cutaneous Inflammasome Activation

The World Health Organization estimates that 7 million people die every year due to pollution exposure. Among the different pollutants to which living organism are exposed, ozone (O₃) represents one of the most toxic, because its location which is the skin is one of the direct tissues exposed to the outdoor environment. Chronic exposure to outdoor stressors can alter cutaneous redox state resulting in the activation of inflammatory pathways. Recently, a new player in the inflammation mechanism was discovered: the multiprotein complex NLRP1 inflammasome, which has been shown to be also expressed in the skin. The topical application of natural compounds has been studied for the last 40 years as a possible approach to prevent and eventually cure skin conditions. Recently, the possibility to use blueberry (BB) extract to prevent pollution-induced skin toxicity has been of great interest in the cosmeceutical industry. In the present study, we analyzed the cutaneous protective effect of BB extract in several skin models (2D, 3D, and human skin explants). Specifically, we observed that in the different skin models used, BB extracts were able to enhance keratinocyte wound closure and normalize proliferation and migration responses previously altered by O₃. In addition, pretreatment with BB extracts was able to prevent ozone-induced ROS production and inflammasome activation measured as NRLP1-ASC scaffold formation and also prevent the transcripts of key inflammasome players such as CASP1 and IL-18, suggesting that this approach as a possible new technology to prevent cutaneous pollution damage. Our data support the hypothesis that BB extracts can effectively reduce skin inflammation and be a possible new technology against cutaneous pollution-induced damage.

Particulate Matter Induces Tissue OxInflammation: From Mechanism to Damage

Significance: Oxidative stress and oxidative damage are central hypothetical mechanisms for the adverse effects of airborne particulate matter (PM). Activation of inflammatory cells capable of generating reactive oxygen and nitrogen species is another proposed damage pathway. Understanding the interplay between these responses can help us understand the adverse health effects attributed to breathing polluted air. Recent Advances: The consequences of PM exposure on different organs are oxidative damage, decreased function, and inflammation, which can lead to the development/exacerbation of proinflammatory disorders. Mitochondrial damage is also an important event in PM-induced cytotoxicity. Critical Issues: Reactive oxygen species (ROS) are generated during phagocytosis of the particles, leading to enhancement of oxidative stress and triggering the inflammatory response. The activation of inflammatory signaling pathways results in the release of cytokines and other mediators, which can further induce ROS production by activating endogenous enzymes, leading to a positive feedback loop, which can aggravate the effects triggered by PM exposure. Future Directions: Further research is required to elucidate the exact mechanisms by which PM exposure results in adverse health effects, in terms of the relationship between the redox responses triggered by the presence of the particles and the inflammation observed in the different organs, so the development/exacerbation of PM-associated health problems can be prevented.

Impact of air quality on the gastrointestinal microbiome: A review

BACKGROUND

Poor air quality is increasingly associated with several gastrointestinal diseases suggesting a possible association between air quality and the human gut microbiome. However, details on this remain largely unexplored as current available research is scarce. The aim of this comprehensive rigorous review was to summarize the existing reports on the impact of indoor or outdoor airborne pollutants on the animal and human gut microbiome and to outline the challenges and suggestions to expand this field of research.

METHODS AND RESULTS

A comprehensive search of several databases (inception to August 9, 2019, humans and animals, English language only) was designed and conducted by an experienced librarian to identify studies describing the impact of air pollution on the human gut microbiome. The retrieved articles were assessed independently by two reviewers. This process yielded six original research papers on the animal GI gastrointestinal microbiome and four on the human gut microbiome. β-diversity analyses from selected animal studies demonstrated a significantly different composition of the gut microbiota between control and exposed groups but changes in α-diversity were less uniform. No consistent findings in α or β-diversity were reported among the human studies. Changes in microbiota at the phylum level disclosed substantial discrepancies across animal and human studies.

CONCLUSIONS

A different composition of the gut microbiome, particularly in animal models, is associated with exposure to air pollution. Air pollution is associated with various taxa changes, which however do not follow a clear pattern. Future research using standardized methods are critical to replicate these initial findings and advance this emerging field.

Impact of air pollution on intestinal redox lipidome and microbiome

Air pollution is a rising public health issue worldwide. Cumulative epidemiological and experimental studies have shown that exposure to air pollution such as particulate matter (PM) is linked with increased hospital admissions and all-cause mortality. While previous studies on air pollution mostly focused on the respiratory and cardiovascular effects, emerging evidence supports a significant impact of air pollution on the gastrointestinal (GI) system. The gut is exposed to PM as most of the inhaled particles are removed from the lungs to the GI tract via mucociliary clearance. Ingestion of contaminated food and water is another common source of GI tract exposure to pollutants. Recent studies have associated air pollution with intestinal diseases, including appendicitis, colorectal cancer, and inflammatory bowel disease. In addition to the liver and adipose tissue, intestine is an important organ system for lipid metabolism, and the intestinal redox lipids might be tightly associated with the intestinal and systematic inflammation. The gut microbiota modulates lipid metabolism and contributes to the initiation and development of intestinal disease including inflammatory bowel disease. Recent data support microbiome implication in air pollution-mediated intestinal and systematic effects. In this review, the associations between air pollution and intestinal diseases, and the alterations of intestinal lipidome and gut microbiome by air pollution are highlighted. The potential mechanistic aspects underlying air pollution-mediated intestinal pathology will also be discussed.

Role of Mitochondria in the Redox Signaling Network and Its Outcomes in High Impact Inflammatory Syndromes

Inflammation is associated with the release of soluble mediators that drive cellular activation and migration of inflammatory leukocytes to the site of injury, together with endothelial expression of adhesion molecules, and increased vascular permeability. It is a stepwise tightly regulated process that has been evolved to cope with a wide range of different inflammatory stimuli. However, under certain physiopathological conditions, the inflammatory response overwhelms local regulatory mechanisms and leads to systemic inflammation that, in turn, might affect metabolism in distant tissues and organs. In this sense, as mitochondria are able to perceive signals of inflammation is one of the first organelles to be affected by a dysregulation in the systemic inflammatory response, it has been associated with the progression of the physiopathological mechanisms. Mitochondria are also an important source of ROS (reactive oxygen species) within most mammalian cells and are therefore highly involved in oxidative stress. ROS production might contribute to mitochondrial damage in a range of pathologies and is also important in a complex redox signaling network from the organelle to the rest of the cell. Therefore, a role for ROS generated by mitochondria in regulating inflammatory signaling was postulated and mitochondria have been implicated in multiple aspects of the inflammatory response. An inflammatory condition that affects mitochondrial function in different organs is the exposure to air particulate matter (PM). Both after acute and chronic pollutants exposure, PM uptake by alveolar macrophages have been described to induce local cell activation and recruitment, cytokine release, and pulmonary inflammation. Afterwards, inflammatory mediators have been shown to be able to reach the bloodstream and induce a systemic response that affects metabolism in distant organs different from the lung. In this proinflammatory environment, impaired mitochondrial function that leads to bioenergetic dysfunction and enhanced production of oxidants have been shown to affect tissue homeostasis and organ function. In the present review, we aim to discuss the latest insights into the cellular and molecular mechanisms that link systemic inflammation and mitochondrial dysfunction in different organs, taking the exposure to air pollutants as a case model.

Seasonal variations in the occurrence of acute appendicitis and their relationship with the presence of fecaliths in children

Background

Acute appendicitis (AA) is the most common surgical condition in children. Although a higher incidence of AA in summer has been reported, the reason for this observation remains unclear. The purpose of this study was to compare the clinical findings of AA patients who underwent appendectomies during the summer months with those who underwent the procedure during the non-summer months.

Methods

The clinical data of 171 patients who underwent appendectomy from January 2013 to December 2016 were reviewed. The patients were divided into a summer group (from May to October) and a non-summer group (from November to April) based on the month when appendectomy was performed. All patients were under 18 years of age at the time of surgery. The medical records including laboratory data, computed tomography scans, pathology reports and operative notes were reviewed.

Results

The number of patients with AA was higher in the summer group than in the non-summer group (101 vs. 70 patients). No significant differences in the laboratory results between the two groups of patients were observed. The percentage of AA patients who presented with a fecalith was significantly lower in the summer group (33.6%) than in the non-summer group (55.7%). No significant differences in the incidence of appendiceal perforations and abscesses, as well as postoperative complications were observed between the two groups.

Conclusions

The percentage of AA patients with fecaliths in summer was lower than that in the non-summer months. The increase in the number of AA patients in summer may be due to the increased occurrence of lymphoid hyperplasia, which may be correlated with the yearly outbreak of enterovirus infection during this period.

Ambient air quality as risk factor for microscopic colitis - A geographic information system (GIS) study

BACKGROUND

Microscopic colitis (MC) is considered a multifactorial disease, strongly associated with smoking. However, little is known about the role of environmental factors such as ambient air pollution in MC pathophysiology. There is an overlap in components of cigarette smoke and ambient air pollution. Therefore, the aim of this study was to explore an independent association between ambient air quality and MC.

METHODS

A case-control study was performed. MC cases in South Limburg, the Netherlands, diagnosed between 2000 and 2012, were retrieved from the national pathology registry and matched to non-MC controls from the same area based on age (±2 years) and gender. A stable residential address for ≥3 years was required. Residential land use, proximity to major road, and concentrations of air pollution compounds, were determined using a Geographic Information System (GIS). Univariate and multivariable regression analyses were corrected for age, gender and smoking status.

RESULTS

In total, 345 MC cases (78.6% female) and 583 matched controls (77.2% female) were included. In the univariate analyses, the percentage of urban green within a 500 m buffer and residential proximity to the nearest highway were associated with MC (both p < 0.10). On the multivariable level only a higher age at diagnosis (OR 1.02, 95%-CI 1.01-1.04) and current smoking at index date (OR 4.30; 95%-CI 3.01-6.14) were significantly associated with MC.

CONCLUSION

Based on the current findings, ambient air quality does not seem to be an important risk factor for MC, in contrast to the well-known risk factors age and current smoking.

Exploring geographic variation in acute appendectomy in Ireland: results from a national registry study

OBJECTIVE

To explore geographic variations in Irish laparoscopic and open appendectomy procedures.

DESIGN

Analysis based on 2014-2017 administrative hospital data from public hospitals.

SETTING

Counties of Ireland.

PARTICIPANTS

Irish residents with hospital admissions for an appendectomy as the principal procedure.

MAIN OUTCOME MEASURES

Age and gender standardised laparoscopic and open appendectomy rates for 26 counties. Geographic variation measured with the extremal quotient (EQ), coefficient of variation (CV) and the systematic component of variation (SCV).

RESULTS

23 684 appendectomies were included. 77.6% (n= 18,387) were performed laparoscopically. An EQ of 8.3 for laparoscopy and 10.0 for open appendectomy was determined. A high CV was demonstrated with a value of 36.7 and 80.8 for laparoscopic and open appendectomy, respectively. An SCV of 14.2 and 124.8 for laparoscopic and open appendectomy was observed. A wider variation was determined when children and adults were assessed separately.

CONCLUSIONS

The geographic distribution in rates of appendectomy varies considerably across Irish counties. Our data suggest that a patient's likelihood of undergoing a laparoscopic or open appendectomy is associated with their county of residence.

The Characteristics of Appendicoliths Associated with Acute Appendicitis

Introduction

Differences between appendicoliths associated with appendicitis and those found incidentally have not been studied. The objective of this study was to determine the characteristics of appendicoliths that are associated with acute appendicitis.

Methods

A cross-sectional study of patients with appendicoliths identified on computed tomographic (CT) scan from January 2008 till December 2014 was conducted. Patients were divided into two group: appendicitis and appendicoliths (AA) and incidentally discovered appendicoliths (IA).

Results

Overall, 321 patients were included in the study. Of these, 103 (32%) patients were in the AA group while 218 (68%) patients were in the IA group. Both groups were similar in age and gender distribution. Significantly greater proportion of patients in the AA group had more than one appendicolith [AA vs. IA: 63 (62%) vs. 82 (38%), p < 0.001], appendicolith location at the base [AA vs. IA: 34 (33%) vs. 33 (15%), p < 0.001] and appendicolith diameter of 5 mm or more [AA vs. IA: 71 (69%) vs. 28 (13%), p < 0.001]. On multivariate analysis, more than one appendicolith [Odds ratio (OR): 1.9, 95% CI: 1.1-3.4; p = 0.02] and diameter of 5 mm or more (OR: 13, 95% CI: 7.1-23.6; p < 0.001) were independently associated with acute appendicitis.

Conclusion

Multiple appendicoliths and appendicoliths larger than 5 mm are associated with acute appendicitis.

Colonic Injuries Induced by Inhalational Exposure to Particulate-Matter Air Pollution

Particulate matter (PM) exposure has been associated with intestinal disorders. Therefore, there is an urgent need to understand the precise molecular mechanism involved and explore potential prevention strategies. In this study, inhaled PM is shown to activate inflammatory pathways in murine colon. In a panel study, it is found that ambient PM levels are significantly associated with elevated number of fecal white blood cells in healthy subjects. Acting as a promoter, PM exposure accelerates chemical carcinogenesis-induced colonic tumor formation in a murine model. Mechanistically, RNA-seq assays suggest activation of phosphoinositide 3-kinase (PI3K)/AKT cascades in chronically PM-exposed human colon mucosal epithelial cells. Ablation of up-stream driver fibroblast growth factor receptor 4 (FGFR4) effectively inhibits inflammation and neoplasia in PM-exposed murine colons. Notably, dietary curcumin supplement is shown to protect against PM-induced colonic injuries in mice. Collectively, these findings identify that PM exposure accelerates colonic tumorigenesis in a PI3K/AKT-dependent manner and suggests potential nutrient supplement for prevention.

Ambient Air Pollution and Hospital Admissions for Peptic Ulcers in Taipei: A Time-Stratified Case-Crossover Study

Very few studies have been performed to determine whether there is a relationship between air pollution and increases in hospitalizations for peptic ulcer, and for those that have occurred, their results may not be completely relevant to Taiwan, where the mixture of ambient air pollutants differ. We performed a time-stratified case-crossover study to investigate the possible association between air pollutant levels and hospital admissions for peptic ulcer in Taipei, Taiwan. To do this, we collected air pollution data from Taiwan's Environmental Protection Agency and hospital admissions for peptic ulcer data for the years 2009-2013 from Taiwan's National Health Insurance's research database. We used conditional logistic regression to analyze the possible association between the two, taking temperature and relative humidity into account. Risk was expressed as odds ratios and significance was expressed with 95% confidence intervals. In our single pollutant model, peptic ulcer admissions were significantly associated with all pollutants (PM₁₀, PM_2.5, SO₂, NO₂, CO, and O₃) on warm days (>23 °C). On cool days (<23 °C), peptic ulcer admissions were significantly associated with PM₁₀, NO₂, and O₃. In our two-pollutant models, peptic ulcer admissions were significantly associated NO₂ and O₃ when combined with each of the other pollutants on warm days, and with PM₁₀, NO₂, and O₃ on cool days. It was concluded that the likelihood of peptic ulcer hospitalizations in Taipei rose significantly with increases in air pollutants during the study period.

Multiple organ injury in male C57BL/6J mice exposed to ambient particulate matter in a real-ambient PM exposure system in Shijiazhuang, China

The development of a rodent ambient particulate matter (PM) inhalation system is critical for drawing causal inferences between PM exposure and the onset of human diseases. In this study, we constructed a real-ambient PM exposure system to investigate multi-organ injury and the reversibility of the impairments in C57BL/6 J male mice exposed to PM with a duration of up to three months in Shijiazhuang, a city with the highest PM2.5 concentration in China. This unique exposure system provided an optimal scenario for round-the-clock PM exposure absent a change in the physiochemical properties of PM and minimized the disturbance to the mice habitat. The mean concentration of PM2.5 in the exposure chambers was 89.95, 79.98, and 87.87 μg/m³ at three different time points, respectively: weeks 1-3, week 1-6, and week 1-12. The injury in multiple organs, including lung, brain, heart, testis, and intestine, was profound and was evident by the significant pathological and functional alterations. Pulmonary pathological examination revealed severe interstitial inflammatory and alveolar hemorrhage throughout the exposure, which was in line with the reduced lung function and the increased cytokine excretion in bronchoalveolar lavage fluid and blood plasma. Notably, the PM-mediated inflammatory response in different systems was correlated with the severity of the injury and the attenuation of pulmonary lesions in the recovery group. Thus, the PM2.5-induced inflammatory response, the chemical components-induced cytotoxicity, genetic damage, and oxidative stress might be implicated in the impairment of multiple murine organs. These findings revealed the severity, sensitivity, and reversibility of multi-organ injury in response to a real-ambient PM exposure.

Influence of Environmental Factors in the Development and Outcomes of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which mainly comprises Crohn's disease (CD) and ulcerative colitis (UC), is a term for chronic inflammatory diseases of the gut arising due to a dysregulated immune response to a dysbiotic gut microbiome on a background of genetic predisposition. However, genetics explains a small fraction of risk, and the external environment plays a large and important role in disease pathogenesis and natural history. Cigarette smoking, one of the earliest- and most-studied risk factors, increases the risk of CD onset and is associated with severe disease. In contrast, although smoking cessation increases the risk of UC onset and relapse, current smoking appears to be protective. Appendectomy is inversely associated with the risk of UC. Various dietary factors may influence risk of IBD, including an inverse association with dietary fiber. Exclusion diets have anecdotal reports of efficacy but lack evidence from rigorous clinical trials. Psychosocial factors such as depression, stress, and sleep disturbance play a role in onset as well as in determining natural history. There is an important need for rigorous studies robustly informing the association and mechanism(s) of influence of the external environment on IBD risk and for clinical trials examining the efficacy of alteration of the environment in ameliorating the course of IBD.

Association of meteorological factors with pediatric acute appendicitis in China: A 7-year retrospective analysis

Acute appendicitis (AA) affects between 7% and 8% of the world population and is one of the most common general surgical emergencies. The concept of seasonal patterns in the incidence of AA remains controversial. Thus, this study aimed to investigate whether meteorological factors are related to variations in the rate of pediatric AA cases at the Children's Hospital in Chongqing, China.In total, in this retrospective survey, 3436 children younger than 18 years who had been hospitalized with AA from January 1, 2008 to December 31, 2013 were enrolled, and the meteorological factors during this period were collected.Patients with AA showed a male/female ratio of 1.81:1; the highest incidence age ranged from 6 to 12 years old (P < .0001). The highest incidences of pediatric AA occurred in summer and autumn, with a peak in September and a trough in February. Pearson correlation analysis showed that the monthly mean temperature (r = 0.357, P = .001), monthly mean relative humidity (r = -0.357, P = .001), and monthly mean sunshine duration (r = 0.235, P = -0.031) were relatively weak correlated with pediatric AA. Multiple linear regression analysis indicated that pediatric AA occurrence was positively affected by monthly mean temperature (P < .0001) and negatively affected by monthly mean humidity (P < .0001) and monthly sum of sunshine (P < .0001), while monthly mean air pressure (P = .092), monthly wind speed (P = .143) and monthly precipitation (P = .297) were marginally associated with pediatric AA.Pediatric AA is associated with climatic factors. Specifically, pediatric AA is more likely related to the following meteorological conditions of: high temperature (20 °C-30 °C), low humidity, and less sunshine.

Inhalational exposure to particulate matter air pollution alters the composition of the gut microbiome

Recent studies suggest an association between particulate matter (PM) air pollution and gastrointestinal (GI) disease. In addition to direct deposition, PM can be indirectly deposited in oropharynx via mucociliary clearance and upon swallowing of saliva and mucus. Within the GI tract, PM may alter the GI epithelium and gut microbiome. Our goal was to determine the effect of PM on gut microbiota in a murine model of PM exposure via inhalation. C57BL/6 mice were exposed via inhalation to either concentrated ambient particles or filtered air for 8-h per day, 5-days a week, for a total of 3-weeks. At exposure's end, GI tract tissues and feces were harvested, and gut microbiota was analyzed. Alpha-diversity was modestly altered with increased richness in PM-exposed mice compared to air-exposed mice in some parts of the GI tract. Most importantly, PM-induced alterations in the microbiota were very apparent in beta-diversity comparisons throughout the GI tract and appeared to increase from the proximal to distal parts. Changes in some genera suggest that distinct bacteria may have the capacity to bloom with PM exposure. Exposure to PM alters the microbiota throughout the GI tract which maybe a potential mechanism that explains PM induced inflammation in the GI tract.

Effects of ambient air pollution exposure on frequency of hospital admissions for appendicitis in Taipei, Taiwan

The relationship between exposure to ambient air pollutants and hospital admissions for appendicitis is not known. This study examined whether an association existed between air contaminant levels and frequency of hospital admissions for appendicitis in Taipei, Taiwan. Ambient air pollution and hospital admission data for Taipei were obtained for 2009-2013. Relative risk (RR) of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single pollutant model, on warm days (> 23°C), number of appendicitis admissions was significantly associated with particulate matter (PM_2.5), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). On cool days (< 23°C), a significant rise in number of admissions for appendicitis was related to PM₁₀, NO₂, and O₃ concentrations. In the two-pollutant models, on warm days, NO₂ and O₃ were significantly associated with increased number of admissions for appendicitis when combined with each of the other pollutants. On cool days, NO₂, O₃, and PM₁₀ remained significant for higher appendicitis admission cases in all two-pollutant models. In conclusion, higher levels of ambient air pollutants may be associated with increase in the risk of hospital admissions for appendicitis in Taipei.

Seasonal variation of acute appendicitis

Objective:

To determine the seasonal variation of acute appendicitis.

Methods:

A total of 320 patients fulfilling the inclusion criteria were enrolled in the study after getting the written informed consent. Appendectomies were performed by consultant surgeons and residents. After surgery histopathological examination of specimens was performed by consultant Histopathologists at Armed Forces Institute of Pathology Rawalpindi and CMH Peshawar. The patients presenting in different four seasons September to November as autumn, December to February as winter, March to May as spring, June to August as summer, were compared to determine seasonal variations.

Results:

In our study out of all 320 patients 188 (58.75%) were males and 132 (41.25%) were females. Sixty patients (18.75 %) presented in autumn season (Sep-Nov), 52 patients (16.25%) in winter season (Dec-Feb), 78 (24.25%) patients in Spring season (Mar-May).130 (40.62%) patients presented in Summer season (Jun-Aug). There was almost 24.37% increased incidence in summer as compared to winter season, 21.87% increased incidence as compared to autumn season, 16.37% increased incidence as compared to spring season.

Conclusion:

Acute appendicitis incidence is increased in summer months in Pakistan. Preventive measures can be taken during summer season (June to Aug) to decrease morbidity and mortality associated with this disease.