Effect of endotoxin and allergens on neonatal lung function and infancy respiratory symptoms and eczema

Indoor Particulate Matter in Urban Households: Sources, Pathways, Characteristics, Health Effects, and Exposure Mitigation

Particulate matter (PM) is a complex mixture of solid particles and liquid droplets suspended in the air with varying size, shape, and chemical composition which intensifies significant concern due to severe health effects. Based on the well-established human health effects of outdoor PM, health-based standards for outdoor air have been promoted (e.g., the National Ambient Air Quality Standards formulated by the U.S.). Due to the exchange of indoor and outdoor air, the chemical composition of indoor particulate matter is related to the sources and components of outdoor PM. However, PM in the indoor environment has the potential to exceed outdoor PM levels. Indoor PM includes particles of outdoor origin that drift indoors and particles that originate from indoor activities, which include cooking, fireplaces, smoking, fuel combustion for heating, human activities, and burning incense. Indoor PM can be enriched with inorganic and organic contaminants, including toxic heavy metals and carcinogenic volatile organic compounds. As a potential health hazard, indoor exposure to PM has received increased attention in recent years because people spend most of their time indoors. In addition, as the quantity, quality, and scope of the research have expanded, it is necessary to conduct a systematic review of indoor PM. This review discusses the sources, pathways, characteristics, health effects, and exposure mitigation of indoor PM. Practical solutions and steps to reduce exposure to indoor PM are also discussed.

Biological Composition of Respirable Particulate Matter in an Industrial Vicinity in South Africa

There is a growing concern that exposure to particulate matter of aerodynamic diameter of less than 2.5 µm (PM2.5) with biological composition (bioaerosols) may play a key role in the prevalence of adverse health outcomes in humans. This study determined the bacterial and fungal concentrations in PM2.5 and their inhalation health risks in an industrial vicinity in South Africa. Samples of PM2.5 collected on a 47-mm glass fiber filter during winter and summer months were analysed for bacterial and fungal content using standard methods. The health risks from inhalation of bioaerosols were done by estimating the age-specific dose rate. The concentration of bacteria (168⁻378 CFU/m³) was higher than fungi (58⁻155 CFU/m³). Bacterial and fungal concentrations in PM2.5 were lower in winter than in the summer season. Bacteria identified in summer were similar to those identified in winter: Staphylococcus sp., Bacillus sp., Micrococcus sp., Flavobacterium sp., Klebsiella sp. and Pseudomonas sp. Moreover, the fungal floras identified include Cladosporium spp., Aspergillus spp., Penicillium spp., Fusarium spp. and Alternaria spp. Children inhaled a higher dose of bacterial and fungal aerosols than adults. Bacteria and fungi are part of the bioaerosol components of PM2.5. Bioaerosol exposure may present additional health risks for children.

Factors affecting ambient endotoxin and particulate matter concentrations around air vents of subway stations in South Korea

Levels of airborne endotoxins and particulate matter less than 10 μm and 2.5 μm in diameter (PM) were measured in the air vents of subway stations in Seoul, South Korea, and factors affecting both pollutants were analyzed. The measurements were completed from March 2016 to February 2017 for eight air vents situated at the ground level around the subway stations. A total of 166 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from not detected to 1.986 EU m^-3, with a mean of 0.227 EU m^-3. The results showed significantly different PM levels from the measurements reported by AIRKOREA as part of the comprehensive air quality index. This can be attributed to different sampling sites in the same area. Endotoxin levels tended to be higher in fall compared to summer. Airborne bacteria levels showed a pattern similar to the endotoxin levels, but no significant association was reported between them. The levels of endotoxins around air vents with a glass cover and streets that allowed smoking were significantly higher than those not containing a walled barrier and streets in which smoking was prohibited. Multivariate regression analysis showed that the factors affecting endotoxin levels comprised air vents with a glass cover (coefficient = 0.106, p = 0.014) and season (coefficient = 0.062, p < 0.0001). Therefore, installing barriers on the air vents and prohibiting smoking in streets to which the vents open may be effective ways to lessen exposure to airborne endotoxin levels around air vents.

Prevention of allergies in childhood - where are we now?

Allergic diseases represent an increasing health problem for children worldwide. Along with allergic airway diseases, food allergy comes to the fore and herewith closely intertwined the hypothesis that an early allergic sensitization might occur via skin barrier defect(s). The importance of the skin barrier has been documented by several studies meanwhile. Not only genetic studies screen the associations between Filaggrin loss-of-function mutations, atopic dermatitis, allergic sensitization, food allergy and even airway diseases, but also epidemiological studies cast new light on the hypothesis of the atopic march. As another focus in context of the development of an allergic phenotype, the specific microbial exposure with all its diversities has been crystallized as it shapes the immune system in (early) infancy. Studies explored both, the role of human intestinal microbiota as well as the external microbial diversity. Unfortunately suitable markers for atopic predictors are still rare. New studies point out that specific IgE antibodies (e.g., IgE to Phl p 1) in children without allergic symptoms so far, might function as a pre-clinical biomarker, which may help to identify candidates for primary (allergen non-specific) or secondary (allergen-specific) prevention in terms of specific immunoprophylaxis. These manifold research activities document a complex increase in knowledge. Nevertheless new assumptions need to be substantively confirmed in order to finally generate the urgently needed preventive strategies for allergic diseases in childhood.

Health Outcomes of Exposure to Biological and Chemical Components of Inhalable and Respirable Particulate Matter

Particulate matter (PM) is a key indicator of air pollution and a significant risk factor for adverse health outcomes in humans. PM is not a self-contained pollutant but a mixture of different compounds including chemical and biological fractions. While several reviews have focused on the chemical components of PM and associated health effects, there is a dearth of review studies that holistically examine the role of biological and chemical components of inhalable and respirable PM in disease causation. A literature search using various search engines and (or) keywords was done. Articles selected for review were chosen following predefined criteria, to extract and analyze data. The results show that the biological and chemical components of inhalable and respirable PM play a significant role in the burden of health effects attributed to PM. These health outcomes include low birth weight, emergency room visit, hospital admission, respiratory and pulmonary diseases, cardiovascular disease, cancer, non-communicable diseases, and premature death, among others. This review justifies the importance of each or synergistic effects of the biological and chemical constituents of PM on health. It also provides information that informs policy on the establishment of exposure limits for PM composition metrics rather than the existing exposure limits of the total mass of PM. This will allow for more effective management strategies for improving outdoor air quality.

Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea

This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination.

Recent advances on diagnosis and management of childhood asthma and food allergies

The epidemic of childhood allergic disorders has been associated to the decline of infectious disease. However, exposure to many triggers (airborne viruses, tobacco smoke, pollution, indoor allergens, etc.) contribute to the disease. Breast feeding practices, nutrition, dietary and obesity also play a multifaceted role in shaping the observed worldwide trends of childhood allergies. Guidelines for treatment are available, but their implementation is suboptimal. Then developed countries are slowing learning integrating the development of suitable guidelines with implementation plans. Awareness, psychosocial and family factors strongly influence asthma and food allergy control. Moreover, monitoring tools are necessary to facilitate self-management. By taking into consideration these and many other pragmatic aspects, national public health programs to control the allergic epidemic have been successful in reducing its impact and trace the need for future research in the area.

Exposure to cats: update on risks for sensitization and allergic diseases

Cats are the pets most commonly implicated in the etiology of asthma and allergic disease. However, systematic reviews have concluded that there is a lack of evidence to support the idea that cat exposure in early life increases the risk of allergic disease. Indeed, it appears most likely that cat exposure is protective against allergic diseases. Recent large prospective studies have shown that living with a cat during childhood, especially during the first year of a child's life, could be protective. However, any advice given to the parents should also incorporate how new acquisition of cats can affect other family members, especially those who are already sensitized. Research is urgently needed to determine whether the suggested impact of acquisition of cats in adult life is modified by the person's childhood pet ownership, to help parents who seek advice on whether or not to get a cat.

The effects of various doses of bacterial lipopolysaccharide on the expression of CD63 and the release of histamine by basophils of atopic and non-atopic patients

OBJECTIVE

We tested the effect of various doses of bacterial lipopolysaccharide (LPS, endotoxin) on the expression of CD63 and the in vitro release of histamine by basophils stimulated with ragweed allergen in patients with or without ragweed and mite allergies.

METHODS

The peripheral blood of 11 patients with ragweed allergy, 10 patients with mite allergy and 14 control patients was incubated with ragweed allergen extract following pretreatment with varying doses of LPS. The expression of CD63 in basophils was measured by flow cytometry, and the release of histamine was determined by ELISA.

RESULTS

In the samples of patients with ragweed allergy that were exposed to specific allergen, only high doses of LPS significantly elevated the expression of CD63 (200 ng/ml; 1,000 EU/ml) and the release of histamine (2,000 ng/ml; 10,000 EU/ml). There was no effect of LPS in any other cases.

CONCLUSIONS

Bacterial LPS (endotoxin) concentrations higher than 200 ng/ml (1,000 EU/ml), which rarely occurs in nature, could only activate the basophils from atopic patients whilst in the presence of the specific allergen. Thus, the restoration of the urban, "microbe-poor" milieu with endotoxin (as LPS) can be a promising and harmless approach for allergy prevention.