Promising candidates for allergy prevention

The Use of Prebiotics from Pregnancy and Its Complications: Health for Mother and Offspring—A Narrative Review

Pregnancy involves a metabolic reprogramming that includes changes in the gut microbiota composition in women. Evidence shows that maternal dysbiosis is linked to neonatal dysbiosis, and this factor can determine health status in adulthood. Although there is little literature available on this topic, high heterogeneity is a limitation when examining nutritional interventions. Information has been gathered to contrast the benefits of prebiotic usage, specifically in pregnancy, in its possible complications and in newborns’ gut microbiota development. The objective pursued in this brief narrative review is to provide a clear summary of relevant content when searching with regard to the use of prebiotics in pregnancy, the effects in prenatal and postnatal periods, and to help in clinical decision-making in pregnancy management and lactation. A search has found that the nutritional status of the pregnant mother is key for the earliest microbial colonization in newborns, and thus intervention programs from pregnancy could assure better outcomes in both the mother and offspring. In this sense, prebiotics (administered to mothers who breastfeed or provided in formula milk) are feasible and cost-effective elements that can prevent allergies, colic, and other maladies in newborns.

Early life microbial exposures and allergy risks: opportunities for prevention

Allergies, including asthma, food allergy and atopic dermatitis, are increasing in prevalence, particularly in westernized countries. Although a detailed mechanistic explanation for this increase is lacking, recent evidence indicates that, in addition to genetic predisposition, lifestyle changes owing to modernization have an important role. Such changes include increased rates of birth by caesarean delivery, increased early use of antibiotics, a westernized diet and the associated development of obesity, and changes in indoor and outdoor lifestyle and activity patterns. Most of these factors directly and indirectly impact the formation of a diverse microbiota, which includes bacterial, viral and fungal components; the microbiota has a leading role in shaping (early) immune responses. This default programme is markedly disturbed under the influence of environmental and lifestyle risk factors. Here, we review the most important allergy risk factors associated with changes in our exposure to the microbial world and the application of this knowledge to allergy prevention strategies.

Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper

Farmers constitute a large professional group worldwide. In developed countries farms tend to become larger, with a concentration of farm operations. Animal farming has been associated with negative respiratory effects such as work-related asthma and rhinitis. However, being born and raised or working on a farm reduces the risk of atopic asthma and rhinitis later in life. A risk of chronic bronchitis and bronchial obstruction/COPD has been reported in confinement buildings and livestock farmers. This position paper reviews the literature linking exposure information to intensive animal farming and the risk of work-related respiratory diseases and focuses on prevention. Animal farming is associated with exposure to organic dust containing allergens and microbial matter including alive microorganisms and viruses, endotoxins and other factors like irritant gases such as ammonia and disinfectants. These exposures have been identified as specific agents/risk factors of asthma, rhinitis, chronic bronchitis, COPD and reduced FEV₁. Published studies on dust and endotoxin exposure in livestock farmers do not show a downward trend in exposure over the last 30 years, suggesting that the workforce in these industries is still overexposed and at risk of developing respiratory disease. In cases of occupational asthma and rhinitis, avoidance of further exposure to causal agents is recommended, but it may not be obtainable in agriculture, mainly due to socio-economic considerations. Hence, there is an urgent need for focus on farming exposure in order to protect farmers and others at work in these and related industries from developing respiratory diseases and allergy.

Dog keeping at home before and during pregnancy decreased the risk of food allergy in 1-year-old children

Introduction

The relationship between allergen exposure to animals in pregnancy and the development of allergic symptoms is not clear.

Aim

To evaluate the association between prenatal and postnatal exposure to pet ownership and development of atopic dermatitis, food allergy and wheezing in children at the age of 1 and 2.

Material and methods

The mother-child pairs included in this study were part of the Polish Mother and Child Cohort. Mothers in each trimester of pregnancy and 1 year after childbirth have completed a questionnaire on animal exposure. Children's health status was assessed at around one year and two years of age.

Results

Keeping a dog at home before and during pregnancy (every trimester) decreased the risk of food allergy in the first year of life. On the other hand, keeping any animal other than a dog (cat, hamster, guinea pig, rabbit) before pregnancy and during each trimester separately increased the risk of food allergy in the first year of life of children. Keeping a guinea pig in the first trimester of pregnancy increased the risk of wheezing in the first year of life. The analysis did not show any significant associations between keeping animals at home before and during pregnancy and the occurrence of atopic dermatitis in the second year of life.

Conclusions

Keeping a dog at home before and during pregnancy decreased the risk of food allergy in 1-year-old children. This effect was eliminated in case of having a cat, hamster, guinea pig, or rabbit.

Application of probiotics in adjuvant treatment of infant allergic rhinitis: A randomized controlled study

BACKGROUND

Several studies have suggested that intestinal flora may play an important role in allergic diseases. The purpose of this study was to investigate the effect of probiotics of Bifidobacterium triplex on the symptoms of allergic rhinitis (AR). The effects of this probiotic on the immune system have been reported in some studies, but most previous studies have been in animals.

METHODS/DESIGN

60 infants and young children with AR were randomly divided into 2 groups: probiotics/placebo group. The main outcome was the use of a comprehensive symptom drug score to assess allergy symptoms. In addition, health-related quality of life was investigated (rhinitis quality of life questionnaire). Secondary outcomes included a visual analog scale of allergy burden and a second quality of life questionnaire. This report describes the study design of a randomized controlled trial.

DISCUSSION

The study design described a double-center, randomized, location at the Minda Hospital of Hubei Minzu University and West China Hospital of Sichuan University, which will be focused on the study about probiotics treatment and its effect on AR symptoms.

TRIAL REGISTRATION

It has been registered at http://www.chictr.org.cn/listbycreater.aspx (Identifier: ChiCTR2000031175), Registered March 22, 2020.

Thinking bigger: How early-life environmental exposures shape the gut microbiome and influence the development of asthma and allergic disease

Imbalance, or dysbiosis, of the gut microbiome of infants has been linked to an increased risk of asthma and allergic diseases. Most studies to date have provided a wealth of data showing correlations between early-life risk factors for disease and changes in the structure of the gut microbiome that disrupt normal immunoregulation. These studies have typically focused on one specific risk factor, such as mode of delivery or early-life antibiotic use. Such "micro-level" exposures have a considerable impact on affected individuals but not necessarily the whole population. In this review, we place these mechanisms under a larger lens that takes into account the influence of upstream "macro-level" environmental factors such as air pollution and the built environment. While these exposures likely have a smaller impact on the microbiome at an individual level, their ubiquitous nature confers them with a large influence at the population level. We focus on features of the indoor and outdoor human-made environment, their microbiomes and the research challenges inherent in integrating the built environment microbiomes with the early-life gut microbiome. We argue that an exposome perspective integrating internal and external microbiomes with macro-level environmental factors can provide a more comprehensive framework to define how environmental exposures can shape the gut microbiome and influence the development of allergic disease.

The Effect of Schinus terebinthifolius Raddi (Anacardiaceae) Bark Extract on Histamine-Induced Paw Edema and Ileum Smooth Muscle Contraction

Schinus terebinthifolius Raddi (Anacardiaceae), popularly known as red aroeira, is used in traditional medicine to treat inflammatory, gastric, and respiratory disorders. The aim of this study was to evaluate the antihistaminic activity of S. terebinthifolius (St) bark extract by using in vivo and in vitro experimental models. The effects of St were investigated on contractions induced by histamine, carbachol, and potassium chloride in isolated guinea pig ileum. St was also studied in response to hind paw edema induced by histamine in rats. Experiments revealed that although St (250, 500, and 1,000 µg/mL) reduced the histamine-induced contractions by 9.1 ± 1.8, 50.2 ± 2.0, and 68.9 ± 2.0%, respectively, it did not inhibit contractions induced by carbachol or KCl. The association of St (250 and 500 µg/mL) with hydroxyzine, an H1-antihistamine (0.125 and 0.250 µM), increased the inhibitory effect to 67.0 ± 3.2 and 85.1 ± 2.1%, respectively. Moreover, St (100, 200, and 400 mg/kg) decreased paw edema from its peak by 33.9, 48.4, and 54.8%, respectively, whereas hydroxyzine (70 mg/kg) inhibited the peak edema by 56.5%. Altogether, the results suggest that the bark extract of S. terebinthifolius has an antihistaminic effect (H1).

The microbiome and development of allergic disease

PURPOSE OF REVIEW

First, to review how the global rise in prevalence of asthma prompted studies of the relationships between microbial exposure in early infancy, the rate and pattern of development of immune function, and the development of allergic sensitization and of wheezing in childhood. And, second, to review how those studies laid the groundwork for a possible strategy for primary prevention of asthma through manipulation of the microbiome of the gastrointestinal and/or respiratory tracts.

RECENT FINDINGS

Atopy and asthma are complex diseases thought to result from a 'gene-by-environment' interaction; the rapidity of their rise in prevalence points to a change in environment as most likely causal. Epidemiologic studies noting associations between events in infancy and later development of atopic diseases have suggested that their rise in prevalence is related to a deficiency in microbial exposure in early life. The findings from birth cohort studies of humans and from interventional studies of mice converge in suggesting that a deficiency in microbial colonization of the respiratory or gastrointestinal tract by certain commensal microbes results in skewed development of systemic and/or local immune function that increases susceptibility to allergic sensitization and to viral lower respiratory infection. Recent studies are now honing in on identifying the microbes, or collection of microbes, whose collective functions are necessary for induction of immune tolerance, and thus of reduced susceptibility.

SUMMARY

Atopy and asthma appear to have their roots in an insufficiency of early-life exposure to the diverse environmental microbiota necessary to ensure colonization of the gastrointestinal and/or respiratory tracts with the commensal microbes necessary for induction of balanced, toleragenic immune function. Identification of the commensal bacteria necessary, now ever closer at hand, will lay the groundwork for the development of strategies for primary prevention of atopic disease, especially of childhood asthma.

Mode of delivery and atopic phenotypes: Old questions new insights? A retrospective study

BACKGROUND

To date studies on the relation between mode of delivery and atopic diseases in are controversial.

OBJECTIVE

The aim of the study was to determine a possible relationship between mode of delivery and risk of atopic phenotypes and, to assess the critical role of some pre-and post-natal parameters as a link between mode of delivery and risk of atopy.

METHODS

1516 children were assessed by skin prick tests, serum total and specific IgE levels. Parental reports on demographic and clinical data were also recorded.

RESULTS

Of the 1516 children enrolled for the study, clinical and laboratory informations were obtained from 917 children. 460 children of them were born via CD and 457 via VD. Mode of delivery did not modify the prevalence of immune sensitization and/or allergic diseases. However, CD was associated with increased risk of atopy (p<0.001). Moreover, some parameters such as familiar history of atopy (p<0.001), habits smoking (p<0.05), exclusive artificial feeding (p<0.001); and breast-feeding time (<3months) (p<0.001) were associated with a major risk of atopy in CD group. Additionally, although our study confirmed that breast-feeding is associated to lower serum total IgE levels than artificial-feeding (p<0.001), it seems that the protective role of breast-feeding is negatively influenced from CD. Also in artificial-feeding subjects CD is related to a significant higher levels of IgE than VD (p<0.001).

CONCLUSIONS

Our findings suggest that CD influences only the risk of atopy but no prevalence of immune sensitization and allergic diseases.

Subgroup differences in the associations between dog exposure during the first year of life and early life allergic outcomes

BACKGROUND

The effect of dog exposure on the risk of children developing allergic disease remains controversial. Many analyses have not considered that associations may vary within population subgroups.

OBJECTIVE

To examine whether associations between living with a dog in the first year of life and allergic outcomes vary within subgroups selected a priori (race, gender and delivery mode).

METHODS

Black (n = 496) and White (n = 196) children enrolled in the WHEALS birth cohort study had a clinical examination at age 2 years to assess eczema and allergen-specific IgE (sIgE) and perform skin prick testing (SPT). Whether the child lived with an indoor dog in the first year of life was assessed through interview, as was doctor diagnosis of asthma at ages 3-6 years.

RESULTS

Living with a dog was associated with decreased odds of having ≥ 1 positive SPT (OR = 0.56, 95% CI: 0.34, 0.91) and having eczema (OR = 0.34, 95% CI: 0.20, 0.60). The association with SPT was stronger in those children born via caesarean section (c-section) vs. vaginally (OR = 0.29, 95% CI: 0.12, 0.74 vs. OR = 0.76, 95% CI: 0.43, 1.37, respectively, interaction P = 0.087) and in those who were firstborn vs. not (OR = 0.27, 95% CI: 0.11, 0.67 vs. OR = 0.82, 95% CI: 0.45, 1.47, respectively, interaction P = 0.044). The association with eczema was stronger in children born vaginally compared with those born via caesarean section (OR = 0.17, 95% CI: 0.06, 0.43 vs. OR = 0.65, 95% CI: 0.31, 1.35, respectively, interaction P = 0.025) and was stronger in Black vs. White children (OR = 0.30, 95% CI: 0.15, 0.61 vs. OR = 0.78, 95% CI: 0.29, 2.11, respectively, interaction P = 0.12). Dog keeping was not significantly inversely associated with having ≥ 1 elevated sIgE and only approached statistical significance with asthma.

CONCLUSIONS AND CLINICAL RELEVANCE

Results likely vary between studies due to variability of specific exposure-outcome associations in subgroups defined by other factors as well as the relative distributions of those subgroups. Important allergic disorder associations will be missed without subgroup analyses.

OPINION: Primary prevention of allergy - Will it soon become a reality?

It is generally accepted that allergic diseases are not curable and not preventable, but mainly controllable using pharmacotherapy (i.e. symptomatic medication). Recent research, however, demonstrated that a number of specific interventions can lead to (partial) primary prevention of allergy, especially of atopic dermatitis (AD) and food allergy (FA). Three types of primary prevention strategies have been successfully studied: early administration of bacterial products (most studies are on probiotics), early moisturizing in infants at risk for AD and early exposure to allergenic foods (peanut and egg). Results of these studies indicate that the stage might have been set. Surely, much more research needs to be carried out before advice can be given in clinical practice. This opinion article discusses the three types of beneficial interventions and gives ideas for future research, which might show the way for better strategies in primary prevention of allergic diseases.

Recent Understandings of Pet Allergies

Allergic reactions to pets have been recognized for at least a hundred years. Yet our understanding of the effects of all of the interactions between pet exposures and human immune responses continues to grow. Allergists, epidemiologists, and immunologists have spent years trying to better understand how exposures to pet allergens lead to allergic sensitization (the production of allergen-specific immunoglobulin class E [IgE] antibodies) and subsequent allergic disease. A major new development in this understanding is the recognition that pet exposures consist of not only allergen exposures but also changes in microbial exposures. Exposures to certain pet-associated microbes, especially in the neonatal period, appear to be able to dramatically alter how a child’s immune system develops and this in turn reduces the risk of allergic sensitization and disease. An exciting challenge in the next few years will be to see whether these changes can be developed into a realistic preventative strategy with the expectation of significantly reducing allergic disease, especially asthma.