Association between environmental tobacco smoke and diminished dendritic cell interleukin 10 production during infancy

An Overview of the Obese-Asthma Phenotype in Children

Asthma is the most common chronic disease in childhood. Overweight and obesity are included among the comorbidities considered in patients with difficult-to-treat asthma, suggesting a specific phenotype of the disease. Therefore, the constant increase in obesity prevalence in children and adolescents raises concerns about the parallel increase of obesity-associated asthma. The possible correlation between obesity and asthma has been investigated over the last decade by different authors, who suggest a complex multifactorial relationship. Although the particular non-eosinophilic endotype of obesity-related asthma supports the concept that high body weight precedes asthma development, there is ongoing debate about the direct causality of these two entities. A number of mechanisms may be involved in asthma in combination with obesity disease in children, including reduced physical activity, abnormal ventilation, chronic systemic inflammation, hormonal influences, genetics and additional comorbidities, such as gastroesophageal reflux and dysfunctional breathing. The identification of the obesity-related asthma phenotype is crucial to initiate specific therapeutic management. Besides the cornerstones of asthma treatment, lifestyle should be optimized, with interventions aiming to promote physical exercise, healthy diet, and comorbidities. Future studies should clarify the exact association between asthma and obesity and the mechanisms underlying the pathogenesis of these two related conditions with the aim to define personalized therapeutic strategies for asthma management in this population.

Will every child have allergic rhinitis soon?

OBJECTIVES

Given the increasing prevalence of AR amongst children, we aimed to review the literature regarding the future of AR in this population.

METHODS

We searched the PubMed, Google and Proquest Central databases at Kırıkkale University Library. Search terms used were: "allergic rhinitis", "children", "paediatric", "allergy", "future", "risk factors", "treatment", "pharmacotherapy" and/or "allergen - specific immunotherapy". With regard to risk factors for allergic rhinitis, the terms "Environmental factors", "Improved hygiene", "Increased indoor allergen exposure", "Farms, villages, worms, and other parasites", "Environmental toxicants", "Diet", "Lifestyle changes", "Air pollution" and "Climate factors" were searched for. "Prevention of allergic diseases" and "Allergen-specific immunotherapy in the future" were also included in the search.

RESULTS

AR has a high prevalence and causes considerable morbidity, has associated comorbidity and features specific complications. The principal treatments rely on avoiding the allergens responsible, and administering drug treatment or immunotherapy, which targets specific antigens. Genetic drift does not explain the rising prevalence of allergic disorders, but multifactorial environmental factors are likely culprits. Amongst such environmental factors to consider are the rise in caesarean births, decreases in breast feeding, dietary changes resulting in less fresh produce being consumed, the eradication of intestinal worm infestations, alterations in the way homes are aired and heated, children taking less exercise and being outdoors for shorter periods, whilst also having more contact with pollution.

CONCLUSION

Barring substantial lifestyle alterations, more and more children are likely to develop AR. It may prove feasible to stop allergy developing in the first place through manipulation of the microbiome, but the exact format such a modification should involve remains to be discovered. Molecular allergological techniques do offer the prospect of more precisely targeted immunotherapy, the sole disease modifier at present. However, at present the complexity and cost of such interventions prevents their widespread use and research in this area is still needed. The majority of children with AR are going to be managed using nasal saline sprays, since they are the most straightforward and least risky alternative for first line treatment.

Impact of tobacco smoke on upper airway dendritic cell accumulation and regulation by sinonasal epithelial cells

BACKGROUND

In these studies we examined the impact of environmental tobacco smoke (ETS) and active smoking on sinonasal dendritic cell (DC) subsets in controls or patients with chronic rhinosinusitis with nasal polyps (CRSwNP). In subsequent in-vitro investigations, we examined the influence of cigarette smoke extract (CSE) on human sinonasal epithelial cells' (HSNECs) ability to regulate DC functions.

METHODS

Sinonasal tissue, blood, and hair were collected from patients undergoing sinus surgery. Smoking status and ETS exposure were determined by hair nicotine. DC subsets were examined by flow cytometric analysis. Monocyte-derived dendritic cells (moDCs) were treated with conditioned medium from non-smoked-exposed HSNECs (NS-HSNECs) or cigarette-smoke-extract-exposed HSNECs (CSE-HSNECs) to assess the impact of CSE exposure on HSNEC regulation of moDC functions.

RESULTS

Control subjects who were active smokers displayed increased sinonasal moDC and myeloid dendritic 1 (mDC1) cells and reduced mDC2 cells, whereas, in CRSwNP patients, only moDC and mDC2 cells were altered. ETS was found to increase only moDCs in the CRSwNP patients. In vitro, CSE stimulated HSNEC secretion of the moDC regulatory products chemokine (C-C motif) ligand 20, prostaglandin E2 , and granulocyte-macrophage colony-stimulating factor. CSE exposure also promoted HSNECs to stimulate monocyte and moDC migration. moDCs treated with CSE-HSNEC media stimulated an increase in antigen uptake and expression of CD80 and CD86. Last, CSE-HSNEC-treated moDCs secreted increased levels of interleukin-10, interferon-γ, and thymic stromal lymphopoietin.

CONCLUSION

Active smoking, and to a lesser degree ETS, alters the sinonasal composition of DCs. A potential mechanism to account for this is that cigarette smoke stimulates HSNECs to induce moDC migration, maturation, and activation.

Link between childhood asthma and mental health conditions

Asthma and mental health conditions often coexist and studies support a link between the two disorders. Indeed, an increase in the incidence of depression and anxiety has been reported in children with asthma compared to those without asthma. Direction of causality in the relationship is unclear. Parental stress appears to be an important factor important in the development of infant wheezing. There is support for a working hypothesis, linking inner-city violence and the development of childhood asthma via pathways that include parental mental health conditions, parental nicotine addiction, environmental tobacco smoke, and Th2 skewing in infants. It is anticipated that a better understanding of the above relationships will lead to the development of new targeted treatment strategies for childhood asthma in the future.

Current and future directions in pediatric allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a common pediatric problem that significantly affects sleep, learning, performance, and quality of life. In addition, it is associated with significant comorbidities and complications.

OBJECTIVE

The aim was to provide an update on the epidemiology, comorbidities, pathophysiology, current treatment, and future direction of pediatric AR.

METHODS

Literature reviews in each of these areas were conducted, and the results were incorporated.

RESULTS

The prevalence of AR is increasing in the pediatric population and is associated with significant morbidity, comorbidities, and complications. The mainstay of current treatment strategies includes allergen avoidance, pharmacotherapy, and allergen specific immunotherapy.

CONCLUSIONS

In the future, diagnosis will be improved by microarrayed recombinant allergen testing and therapy will be expanded to include emerging treatments such as sublingual immunotherapy and combination products.

Lung dendritic cell developmental programming, environmental stimuli, and asthma in early periods of life

Dendritic cells (DCs) are important cells of our innate immune system. Their role is critical in inducing adaptive immunity, tolerance, or allergic response in peripheral organs—lung and skin. The lung DCs are not developed prenatally before birth. The DCs develop after birth presumably during the first year of life; exposures to any foreign antigen or infectious organisms during this period can significantly affect DC developmental programming and generation of distinct DC phenotypes and functions. These changes can have both short-term and long-term health effects which may be very relevant in childhood asthma and predisposition for a persistent response in adulthood. An understanding of DC development at molecular and cellular levels can help in protecting neonates and infants against problematic environmental exposures and developmental immunotoxicity. This knowledge can eventually help in designing novel pharmacological modulators to skew the DC characteristics and immune responses to benefit the host across a lifetime.

The impact of perinatal immune development on mucosal homeostasis and chronic inflammation

The mucosal surfaces of the gut and airways have important barrier functions and regulate the induction of immunological tolerance. The rapidly increasing incidence of chronic inflammatory disorders of these surfaces, such as inflammatory bowel disease and asthma, indicates that the immune functions of these mucosae are becoming disrupted in humans. Recent data indicate that events in prenatal and neonatal life orchestrate mucosal homeostasis. Several environmental factors promote the perinatal programming of the immune system, including colonization of the gut and airways by commensal microorganisms. These complex microbial-host interactions operate in a delicate temporal and spatial manner and have an important role in the induction of homeostatic mechanisms.

Cigarette smoke suppresses TLR-7 stimulation in response to virus infection in plasmacytoid dendritic cells

Exposure to environmental tobacco smoke (ETS) is associated with an increase in the frequency and severity of respiratory infections, including bronchiolitis, a clinical syndrome of infancy caused by viruses such as respiratory syncytial virus (RSV). The mechanisms by which ETS increases the risk of viral respiratory infections are largely unknown. A major effector integrating early antiviral and immunostimulatory activities is interferon-α (IFN-α), which is highly produced by plasmacytoid dendritic cells (pDC). In this work, we determined the effect of cigarette smoke extract (CSE) on human pDC immunity in response to a respiratory viral infection. We found that CSE inhibited RSV-induced IFN-α in pDC as well as the release of IL-1β, IL-10 and CXCL10. However, the production of additional cytokines and chemokines such as IL-6, TNF-α, CCL2, CCL3, CCL5 and CXCL8 was not altered. Quantitative RT-PCR analysis indicated that CSE decreased the expression of toll-like receptor (TLR)-7 and interferon regulatory factor (IRF)-7 in RSV-infected pDC. Furthermore, determination of IRF-7 phosphorylation by flow cytometry showed that CSE prevented IRF-7 activation. These data provide evidence that cigarette smoke suppresses key pDC functions upon viral infection by a mechanism that involves downregulation of TLR7 expression and decreased activation of IRF-7.

Environmental contributions to disparities in pregnancy outcomes

One of the most persistent disparities in American health status is the pronounced difference in birth outcomes between non-Hispanic black and non-Hispanic white women. Poor pregnancy outcomes have a substantial impact on mortality, morbidity, and health care costs. Increasing evidence indicates that environmental exposures are associated with poor birth outcomes. This paper reviews the latest research on how environmental exposures affect pregnancy outcomes and then discusses how these exposures may be embedded within a context of significant social and host factor stress. The analysis suggests that environmental, social, and host factors are cumulatively stressing non-Hispanic black women and that this cumulative stress may be a cause of the persistent disparities in pregnancy outcomes.

Association of passive exposure of pregnant women to environmental tobacco smoke with asthma symptoms in children

Environmental tobacco smoke (ETS) is a significant risk factor for the presence and increased severity of asthma- and allergy-related symptoms in children. Smoking during pregnancy has detrimental effects on asthma-associated outcomes in childhood. Whether passive exposure of pregnant women to ETS may also lead to asthma in their offspring, is not known. The aim of this study was to investigate the association of passive exposure of pregnant women to ETS and asthma- and/or allergy-related symptoms in Preschool children. Cross-sectional data were collected with questionnaires from 2374 Preschool children, recruited from public and private nurseries and day-care centers. Parental smoking was significantly associated with wheezing symptoms in their children. Mother's active smoking during pregnancy significantly increased the risk for occurrence of asthma symptoms and/or medically diagnosed asthma in Preschool children in a dose-dependent manner. Passive exposure to ETS, mainly during the third trimester of pregnancy, was significantly associated with asthma- and allergy-related symptoms after adjusting for several confounders in a multivariate analysis (current wheeze: OR = 1.42, 95% CI = 1.06-1.91, pruritic rash ever: OR= 1.45, 95% CI = 1.01-2.08). Passive exposure of pregnant women to ETS during the third trimester is positively associated with asthma- and allergy-related symptoms in their Preschool age children. Public health policies should be oriented not only towards smoking cessation, but also reinforce elimination of ETS exposure of pregnant women.

Impact of environmental tobacco smoke and active tobacco smoking on the development and outcomes of asthma and rhinitis

PURPOSE OF REVIEW

We aim to discuss current insights on the influence of active smoking and environmental tobacco smoke in lower and upper respiratory inflammatory illnesses.

RECENT FINDINGS

Insight has been gained on the effect of tobacco smoking on the development of asthma from the womb to adolescence. Secondhand tobacco exposure and active smoking play a major role not only in the inception of asthma epidemiological community studies but also in patients already suffering from allergic rhinitis. Tobacco seems to influence innate immunity predisposing to Th2-associated respiratory diseases and increasing the risk for IgE-mediated sensitization. Tobacco smoking is related to worst outcomes in both asthma and rhinitis.

SUMMARY

Several deleterious effects have been described in asthma because of smoking: accelerated decline in lung function, more severe symptoms, impairment in quality of life and diminished therapeutic response to steroids. The harmful effect of tobacco smoking is not only on asthma but also on rhinitis playing a role in disease outcomes. Tobacco exposure can influence innate immunity diminishing innate production of antigen-presenting cells cytokines, as well as an impaired response to toll-like receptor ligands. Active smoking is associated with current symptoms of asthma and rhinitis and seems to be a risk factor for developing new asthma in patients with rhinitis. Tobacco smoking has been also found among the factors inducing nasal obstruction and decreased muco-ciliary clearance in nonallergic rhinitis.

Between a cough and a wheeze: dendritic cells at the nexus of tobacco smoke-induced allergic airway sensitization

Exposure to cigarette smoke represents a major risk factor for the development of asthma. Enhanced sensitization toward allergens has been observed in humans and laboratory animals exposed to cigarette smoke. Pulmonary dendritic cells (DCs) are crucially involved in sensitization toward allergens and play an important role in the development of T helper (Th)2-mediated allergic airway inflammation. We propose the concept that aberrant DC activation forms the basis for the deviation of the lung's default tolerogenic response toward allergic inflammation when harmless antigens are concomittantly inhaled with tobacco smoke. This review will summarize evidence suggesting that tobacco smoke can achieve this effect by providing numerous triggers of innate immunity, which can profoundly modulate airway DC biology. Tobacco smoke can affect the airway DC network either directly or indirectly by causing the release of DC-targeted mediators from the pulmonary tissue environment, resulting in the induction of a Th2-oriented pathological immune response. A thorough knowledge of the molecular pathways involved may open the door to novel approaches in the treatment of asthma.

The V249I polymorphism of the CX3CR1 gene is associated with fibrostenotic disease behavior in patients with Crohn's disease

OBJECTIVES

CX3CR1, the receptor of CX3CL1/fractalkine, is involved in regulation of inflammatory response and the CX3CR1-I249-M280 naturally occurring mutants are associated with altered binding to the ligand. Our aim was to evaluate the frequency of CX3CR1 V249I and T280M polymorphisms and NOD2/CARD15 mutations in Crohn's disease patients and to search for a relationship with phenotype.

METHODS

Clinical data were retrospectively collected. V249I and T280M polymorphisms of CX3CR1 gene and NOD2/CARD15 mutations (R702W, G908R, 3020InsC) were identified.

RESULTS

Two hundred and thirty-nine patients (140 females, 39.7+/-14.1 years) were included. About 37.4% were heterozygous and 8.8% were homozygous for the V249I CX3CR1 polymorphism, 18.1% were heterozygous and 1.3% homozygous for the T280M CX3CR1 polymorphism and 35.9% had at least one of the three mutations of NOD2/CARD15. The T280M CX3CR1 polymorphism was not associated with any phenotype. In univariate analysis, stenosis was significantly associated with both V249I CX3CR1 polymorphism and 3020InsC NOD2/CARD15 mutations. In smoker patients carrying the CX3CR1 allele I249, there was a significant increase in the frequency of fibrostenosing disease [P=0.005, odds ratio (OR): 3.25] whereas this relationship disappeared in the group of nonsmokers (P=0.72). In multivariate analysis, 3020InsC NOD2/CARD15 mutations and the V249I CX3CR1 polymorphism were independent risk factors for intestinal stenosis (P=0.046, OR: 1.8 and P=0.044, OR: 2.4, respectively).

CONCLUSION

In Crohn's disease, V249I CX3CR1 polymorphism is associated with intestinal strictures, particularly in smokers. This association is independent of CARD15 mutations.

Effects of parental smoking on interferon gamma production in children

OBJECTIVES

Environmental tobacco smoke is associated with several negative health outcomes in children, including an increased susceptibility to infections. One of the postulated mechanisms for these effects is the impairment of the immune system function and/or development. Yet, it remains unknown whether cumulative exposure to parental smoking is associated with altered immune responses in childhood and whether these effects are independent of in utero exposure to maternal smoking. In a population-based birth cohort, we sought to determine the relation of parental smoking, as assessed prospectively since pregnancy, to the child's interferon gamma and interleukin 4 production at 11 years of age.

PATIENTS AND METHODS

We used data on 512 children and their parents from the Tucson Children's Respiratory Study cohort. Information on maternal and paternal smoking was collected prospectively by questionnaire, and pack-years for mother, father, and both parents combined were assessed prospectively between the prenatal period and year 11. At age 11 years, children's interferon gamma and interleukin 4 production from mitogen-stimulated peripheral blood mononuclear cells was measured.

RESULTS

Children of parents who smoked between the prenatal period and year 11 were more likely to be in lower quartiles of interferon gamma production than children of nonsmoking parents. In addition, maternal, paternal, and parental pack-years showed significant inverse dose-response relationships with interferon gamma production in the child. These dose-response relationships with interferon gamma remained significant for both paternal and parental pack-years among children of mothers who did not smoke during pregnancy, suggesting the existence of specific postnatal effects of environmental tobacco smoke exposure. In contrast, no significant effects of parental smoking were found on interleukin 4 production.

CONCLUSIONS

Interferon gamma responses of school-aged children are impacted by parental smoking.