Review of Environmental Impact on the Epigenetic Regulation of Atopic Diseases

TSLP regulates mitochondrial ROS-induced mitophagy via histone modification in human monocytes

Background

Thymic stromal lymphopoietin (TSLP) is a Th2-like cytokine involved in asthma pathogenesis. Excessive reactive oxygen species (ROS) production can lead to airway inflammation, hyperresponsiveness and remodeling. Mitophagy, followed by ROS production, is the selective degradation of mitochondria by autophagy and often occurs in defective mitochondria. In the present study, we aimed to examine the effects of TSLP on ROS production and mitophagy in human monocytes and to investigate the underlying mechanisms, including epigenetic regulation.

Results

TSLP induced ROS generation, and the effects were reversed by the antioxidant N-acetylcysteine (NAC) in THP-1 cells. Transmission electron microscopy images showed donut-shaped mitochondria that lost the cristae ultrastructure after TSLP stimulation. A decrease in mitochondrial membrane potential, decreased MTCO2 expression, and increased mitochondrial DNA release after TSLP stimulation were found. TSLP enhanced mitochondrial complex I and complex II/III activity and increased mitochondrial copy numbers and the expression of the complex II SHDA gene. TSLP-induced SHDA expression was inhibited by the histone acetyltransferase inhibitor anacardic acid (AA) and the histone methyltransferase inhibitor methylthioadenosine (MTA), and chromatin immunoprecipitation assays revealed that TSLP enhanced H3 acetylation, H4 acetylation, and H3K4 and H3K36 trimethylation in the SHDA promoter. Confocal laser microscopy showed that TSLP treatment increased the signals of the mitophagy-related proteins PINK1, LC3, phospho-parkin and phospho-ubiquitin, and pretreatment with AA and MTA reduced TSLP-induced PINK1 and LC3 accumulation in mitochondria. Western blot analysis showed that TSLP significantly increased phosphor-AMPK signal intensity, and the effects were inhibited by the antioxidant NAC. The increased signal intensities of the mitophagy-related proteins PINK1, Parkin and LC3 I/II were decreased by dorsomorphin, an AMPK inhibitor. TSLP decreased M1-related cytokine CXCL-10 production and increased M2-related cytokine CCL-1 and CCL-22 production, which was suppressed by the mitophagy inhibitor Mdivi-1 and PINK1 gene knockdown.

Conclusions

Epithelial-derived TSLP regulates ROS production and mitophagy through AMPK activation and histone modification and alters M1/M2 chemokine expression in human monocytes.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00767-w.

Prospects for Use of Single-Cell Sequencing to Assess DNA Methylation in Asthma

Asthma is a complex disease with an increasing prevalence rate caused by the interaction of multiple genetically inherited and environmental factors. Epigenetics link genetic susceptibility and environmental factors. DNA methylation is an epigenetic modification that plays a crucial role in the regulation of growth and development, gene expression, and disease. Relatively little is known about DNA methylation in asthma, with few studies to date using single-cell sequencing to analyze the molecular mechanism by which DNA methylation regulates asthma. Cells with similar phenotypes may be heterogeneous in function and transcription, as may their genetic information. Although multi-omics methods, such as studies of the genome, transcriptome, and epigenome, can be used to evaluate biological processes, these methods are applicable only to groups of cells or tissues and provide averages that may obscure direct correlations among multiple layers of data. Single-cell sequencing technology can clarify the methylation and expression of genes in different populations of cells, in contrast to traditional multi-omics sequencing, which can determine only average values of cell populations. Single-cell sequence can therefore better reflect the pathogenesis of asthma, as it can clarify the function and regulatory mechanism of DNA methylation in asthma, and detect new genes and molecular markers that may become therapeutic targets in this disease.

Pre- and postnatal Lactobacillus reuteri treatment alters DNA methylation of infant T helper cells

BACKGROUND

Perinatal childhood exposures, including probiotic supplementation, may affect epigenetic modifications and impact on immune maturation and allergy development. The aim of this study was to assess the effects of pre- and postnatal Lactobacillus reuteri supplementation on DNA methylation in relation to immune maturation and allergy development.

METHODS

DNA methylation patterns were investigated for allergy-related T helper subsets using a locus-specific method and at a genome-wide scale using the Illumina 450K array. From a randomised, double-blind, placebo-controlled allergy prevention trial with pre- and postnatal probiotic supplementation, CD4+ T helper cells were obtained at birth (from cord blood), and 12 and 24 months of age (total (placebo/probiotics); locus-specific method: CB = 32 (17/15), 12 months = 24 (9/15), 24 months = 35 (15/20); Illumina: CB = 19 (10/9), 12 months = 10 (6/4), 24 months = 19(11/8)).

RESULTS

Comparing probiotics to placebo, the greatest genome-wide differential DNA methylation was observed at birth, where the majority of sites were hypomethylated, indicating transcriptional accessibility in the probiotic group. Bioinformatic analyses, including network analyses, revealed a module containing 91 genes, enriched for immune-related pathways such as chemotaxis, PI3K-Akt, MAPK and TGF-β signalling. A majority of the module genes were associated with atopic manifestations (OR = 1.43, P = 2.4 × 10^-6 ), and a classifier built on this model could predict allergy development (AUC = 0.78, P = 3.0 × 10^e-3 ). Pathways such as IFN-γ signalling and T-cell activation were more hypermethylated at birth compared with later in life in both intervention groups over time, in line with DNA methylation patterns in the IFNG locus obtained by the locus-specific methodology.

CONCLUSION

Maternal L. reuteri supplementation during pregnancy alters DNA methylation patterns in CD4+ T cells towards enhanced immune activation at birth, which may affect immune maturation and allergy development.

Differential DNA methylation in bronchial biopsies between persistent asthma and asthma in remission

Approximately 40% of asthmatics experience remission of asthma symptoms. A better understanding of biological pathways leading to asthma remission may provide insight into new therapeutic targets for asthma. As an important mechanism of gene regulation, investigation of DNA methylation provides a promising approach. Our objective was to identify differences in epigenome wide DNA methylation levels in bronchial biopsies between subjects with asthma remission and subjects with persistent asthma or healthy controls.We analysed differential DNA methylation in bronchial biopsies from 26 subjects with persistent asthma, 39 remission subjects and 70 healthy controls, using the limma package. The comb-p tool was used to identify differentially methylated regions. DNA methylation of CpG-sites was associated to expression of nearby genes from the same biopsies to understand function.Four CpG-sites and 42 regions were differentially methylated between persistent asthma and remission. DNA methylation at two sites was correlated i n cis with gene expression at ACKR2 and DGKQ Between remission subjects and healthy controls 1163 CpG-sites and 328 regions were differentially methylated. DNA methylation was associated with expression of a set of genes expressed in ciliated epithelium.CpGs differentially methylated between remission and persistent asthma identify genetic loci associated with resolution of inflammation and airway responsiveness. Despite the absence of symptoms, remission subjects have a DNA methylation profile that is distinct from that of healthy controls, partly due to changes in cellular composition, with a higher gene expression signal related to ciliated epithelium in remission versus healthy controls.

Occurrence of pollen season at the end of the first trimester predicts clinical atopic diseases in the offspring: A Finnish population-based study

OBJECTIVE

To evaluate the association between potential exposure to different pollen concentrations at the 11th fetal week and subsequent clinical atopic diseases.

STUDY DESIGN AND SETTING

Parents of 1- to 4-year-old children (N = 3035) returned a questionnaire regarding physician-diagnosed atopic diseases. The children were born between 2001 and 2005 in the province of South Karelia, Finland. Results of allergy tests were collected from patient records in the area.

RESULTS

The prevalence of atopic diseases with sensitisation was higher in children whose 11th fetal week occurred during pollen rather than non-pollen season: atopic eczema 6.3% vs. 4.3% (adjusted odds ratio, aOR 1.58, 95% CI 1.10─2.28), food allergy 5.7% vs. 3.9% (1.63; 1.12─2.38), respiratory allergy or asthma 3.7% vs. 2.2% (2.03; 1.24─3.33) and any atopic diseases 7.4% vs. 5.5% (1.48; 1.07─2.05), respectively. Respectively, the prevalence was higher in the children exposed to high rather than low tree pollen concentrations (>1000 vs. <10 particles/m³) at the 11th fetal week: 12.1% vs. 4.4% (3.35; 1.89─5.95), 12.1% vs. 3.9% (3.77; 2.11─6.72), 4.7% vs. 2.5% (2.95; 1.21─7.20) and 14.0% vs. 5.7% (3.15; 1.86─5.35).

CONCLUSION

Coincidence of potential exposure to high tree pollen concentrations at the 11th fetal week is associated with subsequent clinical atopic diseases with sensitisation.

The Role of Diet Diversity and Diet Indices on Allergy Outcomes

Nutrients in foods are not eaten in isolation and food intake interacts in a complex manner, affecting health and disease outcomes. For this reason, focusing on the whole "pattern" of dietary intake instead of the single nutrients or groups of nutrients when studying diseases outcomes is increasingly appealing and growing. Diet diversity refers to the variety of foods being eaten, and the terms, diversity or variety, are often used interchangeably. When the overall diet is characterized by healthy foods, diet diversity will reflect a diversity/variety of healthy foods eaten over a period of time. The introduction of solid foods in the 1st year of life is considered a measure of increased diet diversity. Consuming a diverse range of foods and food allergens in the first year of life may increase intake of important nutrients and positively affect the gut microbiome structure and function. Intake of omega-3 fatty acids and fibers/prebiotics may be particularly important but more information is required about dose and which individuals are most likely to benefit. Increased diet diversity in the first year of life is also associated with reduced food allergy outcomes. In addition to diet diversity, diet indices are considered measures of overall diet quality and can be used as a simple assessment of dietary intake. The focus of this paper is to review and critically address the current knowledge of the association between diet diversity and diet indices and allergy outcomes. Based on the current evidence, we recommend the introduction of solid foods, including common allergenic solids, during the 1st year of life, according to the infant's neuro-developmental abilities and familial or cultural habits. For infants with severe AD and/or FA, medical assessment may be advisable before introducing common food allergens into the diet. Limited evidence exist about the role of diet indices in pregnancy and allergic disease in the offspring, and the most promising results indicate a reduction in childhood wheeze and/or asthma intake.

Epigenetic studies and pediatric research

The 2020 Annual Review Issue, "Preventing Disease in the 21st Century" was selected by the Editors-in-Chief of Pediatric Research to include a variety of disease entities that confront health-care practitioners entrusted to the care of infants and children. In keeping with this mandate, this article reviews the subject of epigenetics, which impacts pediatric research from bench to bedside. Epigenetic mechanisms exert their effects through the interaction of environment, various susceptibility genes, and immunologic development and include: (1) DNA methylation; (2) posttranslational modifications of histone proteins through acetylation and methylation, and (3) RNA-mediated gene silencing by microRNA (miRNA) regulation. The effects of epigenetics during fetal life and early periods of development are first reviewed together with clinical applications of cardiovascular and metabolic disorders in later life. The relationships of epigenetics to the allergic and autoimmune diseases and cancer are next reviewed. A specific focus of the article is directed to the recent recognition that many of these disorders are driven by aberrant immune responses in which immunoregulatory events are often poorly functioning and where through interventive epigenetic measures prevention may be possible by alterations in programming of DNA during fetal and early periods as well as in later life.

Genome-Wide Analysis Reveals Zinc Transporter ZIP9 Regulated by DNA Methylation Promotes Radiation-Induced Skin Fibrosis via the TGF-β Signaling Pathway

Radiation-induced skin fibrosis is a detrimental and chronic disorder that occurs after radiation exposure. DNA methylation has been characterized as an important regulatory mechanism of multiple pathological processes. In this study, we compared the genome-wide DNA methylation status in radiation-induced fibrotic skin and adjacent normal tissues of rats by methylated DNA immunoprecipitation sequencing. Radiation-induced fibrotic skin showed differentially methylated regions associated with 3,650 protein-coding genes, 72 microRNAs, 5,836 long noncoding RNAs and 3 piwi-interacting RNAs. By integrating the mRNA and methylation profiles, the zinc transporter SLC39A9/ZIP9 was investigated in greater detail. The protein level of ZIP9 was increased in irradiated skin tissues of humans, monkeys, and rats, especially in radiogenic fibrotic skin tissues. Radiation induced the demethylation of a CpG dinucleotide in exon 1 of ZIP9 that resulted in recruitment of the transcriptional factor Sp1 and increased ZIP9 expression. Overexpression of ZIP9 resulted in activation of the profibrotic transforming growth factor-β signaling pathway through protein kinase B in human fibroblasts. In addition, radiation-induced skin fibrosis was associated with increased zinc accumulation. The zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)-1,2-ethylenediamine abrogated ZIP9-induced activation of the transforming growth factor-β signaling pathway and attenuated radiation-induced skin fibrosis in a rat model. In summary, our findings illustrate epigenetic regulation of ZIP9 and its critical role in promoting radiation-induced skin fibrosis.

Current Trends in Tolerance Induction in Cow's Milk Allergy: From Passive to Proactive Strategies

This review addresses the current strategies of inducing tolerance development in infant and childhood cow's milk protein allergy (CMPA). The change in prevention strategies for CMPA has been emphasized based on the lack of evidence to support the efficacy of food allergen avoidance in infancy and the concept of the dual-allergen-exposure hypothesis, which suggests that allergen exposure through the skin leads to sensitization, whereas early oral consumption of allergenic food protein induces oral tolerance. The new approach is based on the likelihood of early introduction of allergenic foods to the infant's diet to reduce the development of food allergies through oral tolerance induction. The latest treatment guidelines recommend the continuation of breast feeding and the elimination of cow's milk and products from the maternal diet in exclusively breast-fed infants with CMPA, the use of an extensively hydrolyzed infant formula (eHF) with proven efficacy in CMPA as the first elimination diet in formula-fed infants with CMPA and the use of amino acid-based formula (AAF) in severe cases, such as anaphylaxis, enteropathy, eosinophilic esophagitis, and food protein-induced enterocolitis syndrome (FPIES), as well as cases of multiple system involvement, multiple food allergies, and intolerance to extensively hydrolyzed formula (eHF). In conclusion, this paper presents the current knowledge on tolerance development in infants and children with CMPA to increase the awareness of the clinicians concerning the new approaches in CMPA treatment Tolerance development is considered a relatively new concept in CMPA, inducing a shift in interventions in CMPA from a passive (avoidance of responsible allergen) toward a proactive (tolerance induction) strategy.

Solid Food Introduction and the Development of Food Allergies

The rise of food allergy in childhood, particularly among developed countries, has a significant weight on public health and involves serious implications for patients' quality of life. Even if the mechanisms of food tolerance and the complex interactions between the immune system and environmental factors are still mainly unknown, pediatricians have worldwide implemented preventive measures against allergic diseases. In the last few decades, the prevention of food allergy has tracked various strategies of complementary feeding with a modification of international guidelines from delayed introduction to early weaning. Current evidence shows that complementary foods, including allergenic ones, should be introduced into diet after four months, or even better, following World Health Organization advice, around six months irrespective of risk for allergy of the individual. The introduction of peanut is recommended before 12 months of age among infants affected by severe eczema and/or egg allergy to diminish the occurrence of peanut allergy in countries with high peanut consumption. The introduction of heated egg at 6⁻8 months of age may reduce egg allergy. Infants at high risk of allergy similarly to healthy children should introduce complementary foods taking into account family and cultural preferences.

Chinese Society of Allergy Guidelines for Diagnosis and Treatment of Allergic Rhinitis

Allergic rhinitis (AR) is a global health problem that causes major illnesses and disabilities worldwide. Epidemiologic studies have demonstrated that the prevalence of AR has increased progressively over the last few decades in more developed countries and currently affects up to 40% of the population worldwide. Likewise, a rising trend of AR has also been observed over the last 2-3 decades in developing countries including China, with the prevalence of AR varying widely in these countries. A survey of self-reported AR over a 6-year period in the general Chinese adult population reported that the standardized prevalence of adult AR increased from 11.1% in 2005 to 17.6% in 2011. An increasing number of Journal Articles and imporclinical trials on the epidemiology, pathophysiologic mechanisms, diagnosis, management and comorbidities of AR in Chinese subjects have been published in international peer-reviewed journals over the past 2 decades, and substantially added to our understanding of this disease as a global problem. Although guidelines for the diagnosis and treatment of AR in Chinese subjects have also been published, they have not been translated into English and therefore not generally accessible for reference to non-Chinese speaking international medical communities. Moreover, methods for the diagnosis and treatment of AR in China have not been standardized entirely and some patients are still treated according to regional preferences. Thus, the present guidelines have been developed by the Chinese Society of Allergy to be accessible to both national and international medical communities involved in the management of AR patients. These guidelines have been prepared in line with existing international guidelines to provide evidence-based recommendations for the diagnosis and management of AR in China.

Seasonality and BDNF polymorphism influences depression outcome in patients with atopic dermatitis and psoriasis

OBJECTIVES

To examine the effect of seasonality and rs6265 genotype on depression outcome and brain-derived neurotrophic factor (BDNF) level with dermatitis patients from onset through remission.

METHODS

Atopic dermatitis (AD, 56) and psoriasis (PS, 33) patients and healthy controls (HC, 49) were recruited over the 2014 calendar year. Patients were subdivided by immunoglobulin E (IgE) sensitivity (AD only), season and rs6265 genotype. Assessments were performed at onset and week 10 (Hamilton Depression Rating Scale [HAM-D], SCORAD/PASI, IgE, BDNF). Patients received standard corticosteroid and antihistamine interventions.

RESULTS

All patients responded to corticosteroid treatment. Seasonally differential outcomes were observed in all groups. HAM-D was elevated at onset and improved over 10 weeks: AD cohort 1 (autumn/winter, AD-1) patients improved and AD cohort 2 (spring/summer, AD-2) patients remained elevated. BDNF levels were elevated in AD and seasonal differential: AD-2 declined at 10 weeks, whereas AD-1 remained high (intrinsic AD) or elevated further (extrinsic AD). PS cohort 2 declined to below control at 10 weeks. AD Val/Val had persistently elevated HAM-D and AD Val/Met were either normal (AD-1) or persistently elevated (AD-2).

CONCLUSIONS

Findings presented here suggest a strong influence of seasonality on depression outcome and BDNF expression in AD and PS and likely reflect separate patient populations which differentially respond to environment-based stressors.

Association of Smoking, Alcohol Use, and Betel Quid Chewing with Epigenetic Aberrations in Cancers

Numerous environmental factors such as diet, alcohol use, stress, and environmental chemicals are known to elicit epigenetic changes, leading to increased rates of cancers and other diseases. The incidence of head and neck cancer, one of the most common cancers in Taiwanese males, is increasing: oral cancer and nasopharyngeal carcinoma are ranked fourth and tenth respectively, among the top ten cancers in this group, and a major cause of cancer-related deaths in Taiwanese males. Previous studies have identified smoking, alcohol use, and betel quid chewing as the three major causes of head and neck cancers; these three social habits are commonly observed in Taiwanese males, resulting in an increasing morbidity rate of head and neck cancers in this population. In this literature review, we discuss the association between specific components of betel quid, alcohol, and tobacco, and the occurrence of head and neck cancers, lung cancer, gastrointestinal cancers, and urethral cancer. We focus on regulatory mechanisms at the epigenetic level and their oncogenic effects. The review further discusses the application of FDA-approved epigenetic drugs as therapeutic strategies against cancer.

Sleep-related disorders in Latin-American children with atopic dermatitis: A case control study

BACKGROUND

Atopic dermatitis (AD) has been associated with impairment of sleep. The aim of this study was to evaluate sleep disorders in AD Latin-American children (4-10 years) from nine countries, and in normal controls (C).

METHODS

Parents from 454 C and 340 AD children from referral clinics answered the Children Sleep Habits Questionnaire (CSHQ), a one-week retrospective 33 questions survey under seven items (bedtime resistance, sleep duration, sleep anxiety, night awakening, parasomnias, sleep-disordered breathing and daytime sleepiness). Total CSHQ score and items were analysed in both C and AD groups. Spearman's correlation coefficient between SCORAD (Scoring atopic dermatitis), all subscales and total CSHQ were also obtained.

RESULTS

C and AD groups were similar regarding age, however, significantly higher values for total CSHQ (62.2±16.1 vs 53.3±12.7, respectively) and items were observed among AD children in comparison to C, and they were higher among those with moderate (54.8%) or severe (4.3%) AD. Except for sleep duration (r=-0.02, p=0.698), there was a significant Spearman's correlation index for bedtime resistance (0.24, p<0.0001), sleep anxiety (0.29, p<0.0001), night awakening (0.36, p<0.0001), parasomnias (0.54, p<0.0001), sleep-disordered breathing (0.42, p<0.0001), daytime sleepiness (0.26, p<0.0001) and total CSHQ (0.46, p<0.0001). AD patients had significantly higher elevated body mass index.

CONCLUSION

Latin-American children with AD have sleep disorders despite treatment, and those with moderate to severe forms had marked changes in CSHQ.

Sensitivity to oxazolone induced dermatitis is transferable with gut microbiota in mice

Atopic Dermatitis (AD) has been associated with gut microbiota (GM) dysbiosis in humans, indicating a causative role of GM in AD etiology. Furthermore, the GM strongly correlates to essential disease parameters in the well-known oxazolone-induced mouse model of AD. Here, we demonstrate that it is possible to transfer both a high-responding and a low-responding AD phenotype with GM from conventional mice to germ-free mice. The mice inoculated with the high-responding GM had significantly higher clinical score, increased ear thickness, and increased levels of IL-1β, TNFα, IL-4, IL-5, and IL-6 compared to the mice inoculated with the low-responding GM. The inter-individual variation was in general not affected by this increase in effect size. Germ-free mice induced with AD revealed a high disease response as well as high inter-individual variation indicating protective properties of certain microbial taxa in this model. This study underlines that the GM has a strong impact on AD in mouse models, and that the power of studies may be increased by the application of mice inoculated with a specific GM from high responders to increase the effect size.

The profile of leucocytes, CD3+, CD4+, and CD8+ T cells, and cytokine concentrations in peripheral blood of children with acute asthma exacerbation

Objective

To determine the leucocyte profile and cytokine concentrations in the peripheral blood of children with an acute asthma exacerbation (AAE).

Methods

This descriptive, cross-sectional study enrolled paediatric patients admitted to hospital for AAE. The severity of AAE was assessed using the paediatric asthma score (PAS). Peripheral blood samples were collected for automatic quantification of white blood cell counts, CD3+, CD4+, and CD8+ T cells populations by flow cytometry and cytokine concentrations by flow cytometry-assisted immunoassay.

Results

A total of 127 children with AAE and 30 healthy control subjects were included in the study. The proportion of paediatric patients with decreased CD3+, CD4+ and CD8+ T cells was significantly higher in those with severe AAE compared with those with mild-to-moderate AAE. The concentrations of interleukin (IL)-2, IL-8, IL-12, and IL-4 in paediatric patients with rhinovirus infection were significantly higher than in those without rhinovirus infection. IL-2, IL-4, IL-6, TNF-α and GM-CSF concentrations during AAE were significantly lower than control. IL-5 and IL-13 concentrations during AAE were significantly higher than control.

Conclusions

The decrease of CD3+, CD4+, CD8+ T cells and IL-2, IL-4, IL-6, TNF-α, and GM-CSF combined with the increase of IL-5 and IL-13, were associated with AAE in children with asthma.

Impact of allergy and atopy on the risk of pseudophakic cystoid macular edema

PURPOSE

To assess the risk of pseudophakic cystoid macular edema (PCME) following cataract surgery in patients with allergies and/or atopic disorders.

PATIENTS AND METHODS

Medical records of 3,850 consecutive eyes that underwent cataract surgery were retrospectively reviewed for prevalence of allergies and atopic status and development of PCME. Patients with any known risk factors for PCME were excluded. Macular examination was performed using spectral-domain optical coherence tomography (SD-OCT) before and at 4, 8, 12, 16, 24, and 36 weeks after surgery. If both eyes in one patient underwent cataract surgery, one eye was randomly selected. Odds ratios and confidence intervals were estimated.

RESULTS

Out of 240 patients enrolled in this series, 65 patients (27.1 %) showed positive allergic status, 19 patients (7.9 %) suffered from atopic syndromes, and 11 (4.6 %) showed both (allergies and atopic diseases). PCME occurred in eight patients (12.3 %) of the allergy cohort, whereas no patient (0 %) of the atopy cohort developed PCME. The risk of PCME was comparable in patients with allergies or atopic diseases to patients without allergies or atopy (allergy: p = 0.635; odds ratio (OR) 1.303, 95 % confidence interval (CI) 0.461-3.398; atopy: p = 0.234; OR 0.000, 95 % CI 0-1.815).

CONCLUSION

Positive status of allergy or atopy does not seem to increase the risk of PCME. Therefore, postoperative treatment after cataract surgery does not have to be modified in allergic or atopic patients.

Prevention of food allergy

The past few decades have witnessed an increase in the prevalence of IgE-mediated food allergy (FA). For prevention strategies to be effective, we need to understand the causative factors underpinning this rise. Genetic factors are clearly important in the development of FA, but given the dramatic increase in prevalence over a short period of human evolution, it is unlikely that FA arises through germline genetic changes alone. A plausible hypothesis is that 1 or more environmental exposures, or lack thereof, induce epigenetic changes that result in interruption of the default immunologic state of tolerance. Strategies for the prevention of FA might include primary prevention, which seeks to prevent the onset of IgE sensitization; secondary prevention, which seeks to interrupt the development of FA in IgE-sensitized children; and tertiary prevention, which seeks to reduce the expression of end-organ allergic disease in children with established FA. This review emphasizes the prevention of IgE-mediated FA through dietary manipulation, among other strategies; in particular, we focus on recent interventional studies in this field.

Particulate matter, the newborn methylome, and cardio-respiratory health outcomes in childhood

Ambient air pollution is associated with adverse health outcomes including cardio-respiratory diseases. Epigenetic mechanisms such as DNA methylation may play a role in driving such associations. We investigated the effects of prenatal particulate matter (PM) exposure on DNA methylation of 178,309 promoter regions in 240 newborns using the Infinium HumanMethylation450 BeadChip, using a generalized linear regression model with a quasi-binomial link family, adjusted for gender, plate, and cell types. PM-associated CpG loci were then investigated for their associations with childhood asthma, carotid intima-media thickness (CIMT), and blood pressure (BP) using logistic or linear regression. Thirty-one loci were associated with either PM₁₀ or PM_2.5 using FDR-corrected p-values of less than 0.15. Two loci were evaluated for replication in a separate population of 280 Children's Health Study (CHS) subjects using Pyrosequencing, of which one successfully replicated (COLEC11 cg03579365). Three of the 31 loci were also associated with physician-diagnosed asthma at 6 years old, two were associated with CIMT and one with systolic BP at 10 years old. A higher methylation level in TM9SF2 (cg02015529) and UBE2S (cg00035623), respectively, was associated with a 2SD increase in prenatal PM and was also associated with 36% and 98% increased odds of asthma; whereas methylation of TDRD6 (cg22329831) was negatively associated with PM and a 24% decreased odds of asthma. Prenatal PM exposure was associated with altered DNA methylation in newborn blood in a small number of gene promoters, some of which were also associated with cardio-respiratory health outcomes later in childhood. Keywords: methylation, particulate matter, air pollution, asthma, cardiovascular.