Exposure to ambient ultrafine particles and urinary 8-hydroxyl-2-deoxyguanosine in children with and without eczema

Oxidative Stress in Atopic Dermatitis and Possible Biomarkers: Present and Future

Oxidative stress is important in the pathogenesis of atopic dermatitis (AD); it can damage keratinocytes, increase dermal inflammation, and reduce skin barrier function, the hallmarks of atopic dermatitis pathogenesis. Measuring oxidative stress is possible by identifying peripheral markers, which could have a predictive value of disease severity, disease progression and response to therapy, with a potentially significant impact on patient management. Our review explored this fascinating field of research, focusing on old and new possible biomarkers that may represent an effective tool to investigate the inflammatory-oxidative axis in AD, adding clinically important information to patient care.

Impact of Air Pollution on Atopic Dermatitis: A Comprehensive Review

Air pollution is associated with multiple health problems worldwide, contributing to increased morbidity and mortality. Atopic dermatitis (AD) is a common allergic disease, and increasing evidence has revealed a role of air pollution in the development of atopic dermatitis. Air pollutants are derived from several sources, including harmful gases such as nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO), as well as particulate matter (PM) of various sizes, and bioaerosols. Possible mechanisms linking air pollution to atopic dermatitis include damage to the skin barrier through oxidative stress, increased water loss, physicochemical injury, and an effect on skin microflora. Furthermore, oxidative stress triggers immune dysregulation, leading to enhanced sensitization to allergens. There have been multiple studies focusing on the association between various types of air pollutants and atopic dermatitis. Since there are many confounders in the current research, such as climate, synergistic effects of mixed pollutants, and diversity of study population, it is not surprising that inconsistencies exist between different studies regarding AD and air pollution. Still, it is generally accepted that air pollution is a risk factor for AD. Future studies should focus on how air pollution leads to AD as well as effective intervention measures.

The skin is no barrier to mixtures: Air pollutant mixtures and reported psoriasis or eczema in the Personalized Environment and Genes Study (PEGS)

BACKGROUND

Autoimmune (AI) diseases appear to be a product of genetic predisposition and environmental triggers. Disruption of the skin barrier causes exacerbation of psoriasis/eczema. Oxidative stress is a mechanistic pathway for pathogenesis of the disease and is also a primary mechanism for the detrimental effects of air pollution.

METHODS

We evaluated the association between autoimmune skin diseases (psoriasis or eczema) and air pollutant mixtures in 9060 subjects from the Personalized Environment and Genes Study (PEGS) cohort. Pollutant exposure data on six criteria air pollutants are publicly available from the Center for Air, Climate, and Energy Solutions and the Atmospheric Composition Analysis Group. For increased spatial resolution, we included spatially cumulative exposure to volatile organic compounds from sites in the United States Environmental Protection Agency Toxic Release Inventory and the density of major roads within a 5 km radius of a participant's address from the United States Geological Survey. We applied logistic regression with quantile g-computation, adjusting for age, sex, diagnosis with an autoimmune disease in family or self, and smoking history to evaluate the relationship between self-reported diagnosis of an AI skin condition and air pollution mixtures.

RESULTS

Only one air pollution variable, sulfate, was significant individually (OR = 1.06, p = 3.99E-2); however, the conditional odds ratio for the combined mixture components of PM2.5 (black carbon, sulfate, sea salt, and soil), CO, SO2, benzene, toluene, and ethylbenzene is 1.10 (p-value = 5.4E-3).

SIGNIFICANCE

While the etiology of autoimmune skin disorders is not clear, this study provides evidence that air pollutants are associated with an increased prevalence of these disorders. The results provide further evidence of potential health impacts of air pollution exposures on life-altering diseases.

SIGNIFICANCE AND IMPACT STATEMENT

The impact of air pollution on non-pulmonary and cardiovascular diseases is understudied and under-reported. We find that air pollution significantly increased the odds of psoriasis or eczema in our cohort and the magnitude is comparable to the risk associated with smoking exposure. Autoimmune diseases like psoriasis and eczema are likely impacted by air pollution, particularly complex mixtures and our study underscores the importance of quantifying air pollution-associated risks in autoimmune disease.

Anti-Pollutant Activity of Porphyra yezoensis Water Extract and Its Active Compound, Porphyra 334, against Urban Particulate Matter-Induced Keratinocyte Cell Damage

Urban particulate matter (UPM) causes skin aging and inflammatory reactions by influencing skin cells through the aryl hydrocarbon receptor (AhR) signaling pathway. Porphyra yezoensis (also known as Pyropia yezoensis), a red alga belonging to the Bangiaceae family, is an edible red seaweed. Here, we examined the anti-pollutant effect of P. yezoensis water extract. While UPM treatment induced xenobiotic response element (XRE) promoter luciferase activity, P. yezoensis water extract reduced UPM-induced XRE activity. Next, we isolated an active compound from P. yezoensis and identified it as porphyra 334. Similar to the P. yezoensis water extract, porphyra 334 attenuated UPM-induced XRE activity. Moreover, although UPM augmented AhR nuclear translocation, which led to an increase in cytochrome P450 1A1 (CYP1A1) mRNA levels, these effects were reduced by porphyra 334. Moreover, UPM induced the production of reactive oxygen species (ROS) and reduced cell proliferation. These effects were attenuated in response to porphyra 334 treatment. Furthermore, our results revealed that the increased ROS levels induced by UPM treatment induced transient receptor potential vanilloid 1 (TRPV1) activity, which is related to skin aging and inflammatory responses. However, porphyra 334 treatment reduced this reaction by inhibiting ROS production induced by CYP1A1 activation. This indicates that porphyra 334, an active compound of P. yezoensis, attenuates UP-induced cell damage by inhibiting AhR-induced ROS production, which results in a reduction in TRPV1 activation, leading to cell proliferation. This also suggests that porphyra 334 could protect the epidermis from harmful pollutants.

Importance of Punctual Monitoring to Evaluate the Health Effects of Airborne Particulate Matter

Particulate matter (PM) pollution is one of the major public health problems worldwide, given the high mortality attributable to exposure to PM pollution and the high pathogenicity that is found above all in the respiratory, cardiovascular, and neurological systems. The main sources of PM pollution are the daily use of fuels (wood, coal, organic residues) in appliances without emissions abatement systems, industrial emissions, and vehicular traffic. This review aims to investigate the causes of PM pollution and classify the different types of dust based on their size. The health effects of exposure to PM will also be discussed. Particular attention is paid to the measurement method, which is unsuitable in the risk assessment process, as the evaluation of the average PM compared to the evaluation of PM with punctual monitoring significantly underestimates the health risk induced by the achievement of high PM values, even for limited periods of time.

Oxidative Stress and Gut Microbiome in Inflammatory Skin Diseases

Oxidative stress plays a dominant role in inflammatory skin diseases. Emerging evidence has shown that the close interaction occurred between oxidative stress and the gut microbiome. Overall, in this review, we have summarized the impact of oxidative stress and gut microbiome during the progression and treatment for inflammatory skin diseases, the interactions between gut dysbiosis and redox imbalance, and discussed the potential possible role of oxidative stress in the gut-skin axis. In addition, we have also elucidated the promising gut microbiome/redox-targeted therapeutic strategies for inflammatory skin diseases.

The association between urinary polycyclic aromatic hydrocarbon metabolites and atopic triad by age and body weight in the US population

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are generated during the incomplete combustion of coal/oil/gas and waste. The role of PAH exposure in the atopic triad remains poorly understood. Due to their lipophilic nature, PAHs deposit in adipocytes, potentially placing elderly and those who are overweight at higher risk.

OBJECTIVE

To investigate the association between urinary PAHs and symptoms of atopic triad (chronic pruritus, sneezing, and wheezing).

METHODS

Binary multivariable logistic regression was performed to estimate the association of nine urinary PAHs and atopic diseases followed by subgroup analyses by age (children 6-17, adults 18-49, elderly ≥50 years) and body mass index (BMI) (normal: BMI <25, overweight: BMI ≥ 25 kg/m²) among 2,242 participants of National Health and Nutrition Examination Survey 2005-2006 dataset.

RESULTS

1-hydroxynaphthalene (1-NAP) and hydroxyfluorenes (FLUs) were positively associated with wheezing. When stratified by age, positive associations were found between 1-NAP with wheezing in children/adults and 2-/3-FLU with wheezing in adults/elderly. 3-hydroxyphenanthrene (3-PHE) and 1-hydroxypyrene were positively associated with chronic pruritus in elderly. When stratified by BMI, positive associations were found between 2-PHE with chronic pruritus, 1-NAP and FLUs with wheezing in overweight.

CONCLUSION

Urinary PAH levels were positively associated with atopic triad and this connection was influenced by age and BMI.

Current evidence to support the therapeutic potential of flavonoids in oxidative stress-related dermatoses

BACKGROUND

Skin, as a crucial external defense organ, is more vulnerable to oxidative stress (OS) insult, reactive oxygen species (ROS)-mediated OS in particular. OS results from a redox imbalance caused by various extrinsic stimuli and occurs once the oxidants production overwhelming the antioxidants capacity, through mediating in DNA damage, lipid peroxidation (LPO), protein oxidation and a serial of signaling pathways activation/inactivation, thereby offering favorable conditions for the occurrence and development of numerous diseases especially some dermatoses, e.g. psoriasis, vitiligo, skin photodamage, skin cancer, systemic sclerosis (SSc), chloasma, atopic dermatitis (AD), pemphigus, etc. Targeting OS molecular mechanism, a variety of anti-OS agents emerge, in which flavonoids, natural plant extracts, stand out.

OBJECTIVES

To discuss the possible mechanisms of OS mediating in dermatoses and summarize the properties of flavonoids as well as their applications in OS-related skin disorders.

METHODS

Published papers on flavonoids and OS-related skin diseases were collected and reviewed via database searching on PubMed, MEDLINE and Embase, etc.

RESULTS

It has been confirmed that flavonoids, belonging to polyphenols, are a class of plant secondary metabolites widely distributed in various plants and possess diverse bioactivities especially their potent antioxidant capacity. Moreover, flavonoids benefit to suppress OS via eliminating free radicals and mediating the corresponding signals, further excellently working in the prevention and management of OS-related skin diseases.

CONCLUSION

Flavonoids have the potential therapeutic effects on oxidative stress-related dermatoses. However, more studies on specific mechanism as well as the dosage of flavonoids are needed in future.

Assessment of indoor air exposure among newborns and their mothers: Levels and sources of PM10, PM2.5 and ultrafine particles at 65 home environments

Significant efforts have been directed towards addressing the adverse health effects of atmospheric particles, emphasizing the relevance of indoor exposure. Homes represent an indoor environment where human spend the majority of their time. Thus, the objective of this work was to concurrently assess different matrix of indoor particles considering both mass (PM₁₀, PM_2.5) and number (N_20-1000) concentrations in indoor and outdoor air of homes (n = 65). Real-time measurements (PM₁₀, PM_2.5, UFP) were conducted simultaneously during 48 h in dwellings situated in Oporto, Portugal. In 75% of homes, indoor PM_2.5 (mean = 53 μg m^-3) exceeded limit of 25 μg m^-3, for PM₁₀ (mean = 57 μg m^-3) 41% of homes demonstrated average levels higher than 50 μg m^-3, thus indicating potential risks. Indoor PM₁₀ was mostly (82-99%) composed of PM_2.5, both PM were highly correlated (|rs|>0.9655), thus suggesting the similar origin. Indoor PM originated from infiltrations of outdoor emissions; ∼70% of homes exhibited indoor to outdoor (I/O) ratio < 1. On the contrary, UFP indoors (mean = 13.3 × 10³ # cm^-3) were higher than outdoors (mean = 10.0 × 10³ # cm^-3). Indoor UFP spatially varied as follows: kitchens > living rooms > bedrooms. UFP indoors were poorly correlated (|rs| = 0.456) with outdoor concentrations, I/O ratios showed that indoor UFP predominantly originated from indoor emission sources (combustions). Therefore, in order to reduce exposure to UFP and protect public health, the primary concerns should be focused on controlling emissions from indoor sources.

Non-linear relationships between seasonal exposure to polycyclic aromatic hydrocarbons and urinary 8-hydroxy-2'-deoxyguanosine levels among Chinese young students

Limited data are available on seasonal associations of polycyclic aromatic hydrocarbons (PAHs) exposure with oxidative DNA damage. We conducted a pilot study with 20 postgraduates, and measured urinary levels of mono-hydroxyl PAHs (OH-PAHs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) for 7 consecutive days in the four seasons. We assessed the relationships of urinary OH-PAHs with urinary 8-OHdG in the whole year as well as cold- and warm-seasons. Summed OH-PAHs (∑OH-PAHs) were higher in cold season than in warm season. Each ln-unit (ln-transformed unit) increase in ∑OH-PAHs in the whole year corresponded to a 34%, 16% or 23% increase in urinary 8-OHdG levels at lag0, lag1 or lag2 day as well as a 26% increase in urinary 8-OHdG levels at lag0-2 days (cumulative effects). Each ln-unit increase in ∑OH-PAHs corresponded to a 36%, 26% or 46% increase in urinary 8-OHdG levels in cold season at lag0 day, lag1 day or lag2 day as well as a 36% increase in urinary 8-OHdG in warm season at lag0 day. Distributed non-linear cumulative lag models (DLNMs) indicated that each ln-unit increase in ∑OH-PAHs within the range of 5.7-8.1 nmol/mmol Cr had a stronger effect (coefficient β: 1.11-2.97 nmol/mmol Cr) on urinary 8-OHdG rather than non-cumulative DLNMs (coefficient β: 1.08-1.43 nmol/mmol Cr) as well as the non-linear dose-response relationships of ∑OH-PAHs with urinary 8-OHdG. PAHs exposure exhibited the lagged and cumulative effects on urinary 8-OHdG levels.

The health effects of ultrafine particles

Ultrafine particles (PM_0.1), which are present in the air in large numbers, pose a health risk. They generally enter the body through the lungs but translocate to essentially all organs. Compared to fine particles (PM_2.5), they cause more pulmonary inflammation and are retained longer in the lung. Their toxicity is increased with smaller size, larger surface area, adsorbed surface material, and the physical characteristics of the particles. Exposure to PM_0.1 induces cough and worsens asthma. Metal fume fever is a systemic disease of lung inflammation most likely caused by PM_0.1. The disease is manifested by systemic symptoms hours after exposure to metal fumes, usually through welding. PM_0.1 cause systemic inflammation, endothelial dysfunction, and coagulation changes that predispose individuals to ischemic cardiovascular disease and hypertension. PM_0.1 are also linked to diabetes and cancer. PM_0.1 can travel up the olfactory nerves to the brain and cause cerebral and autonomic dysfunction. Moreover, in utero exposure increases the risk of low birthweight. Although exposure is commonly attributed to traffic exhaust, monitored students in Ghana showed the highest exposures in a home near a trash burning site, in a bedroom with burning coils employed to abate mosquitos, in a home of an adult smoker, and in home kitchens during domestic cooking. The high point-source production and rapid redistribution make incidental exposure common, confound general population studies and are compounded by the lack of global standards and national reporting. The potential for PM_0.1 to cause harm to health is great, but their precise role in many illnesses is still unknown and calls for more research.

Tiny particles found in air pollution enter the body usually through the lungs and disperse to other organs, causing more inflammation and cellular toxicity than larger particles. Dean Schraufnagel from the University of Illinois at Chicago, USA, reviews the way by which nano-sized air pollutants threaten human health. He describes how ultrafine particles measuring less than 100 nanometres in diameter elicit greater inflammatory responses and stay in the lungs longer than larger particles. Repeated contact with extremely small particulate matter can trigger heart disease, diabetes, cancer, neurological disorders and respiratory ailments, especially among children and people with long-term occupational exposure. Much remains to be learned about the disease-causing properties of these nanoparticles and their long-term effects. Further developments in understanding remain handicapped by the lack of international standards and reporting measures.

A novel oxidative stress marker of atopic dermatitis in infants: thiol-disulfide balance

Atopic dermatitis (AD) is a chronic disease of infancy and its pathogenesis remains unclear. There are recent studies suggesting that oxidative stress could play a role in the pathophysiology of atopic dermatitis. The aim of this study was to evaluate thiol (SH)-disulfide (SS) hemostasis as a new marker of oxidative stress (OS) in infants with atopic dermatitis. Thirty-one infants with AD and 30 healthy infants were included in a prospective, cross-sectional study. PO-SCORAD Index of infants with atopic dermatitis was calculated at the time of sample collection. Total antioxidant status (TAS), total oxidant status (TOS), native thiol (-SH), total thiol (-SH + -S-S-), and disulfide (SS) were measured in the control and patient groups. SS/SH, SS/total SH, SH/total SH ratios were compared between the groups. Mean native thiol and total thiol concentrations of the patient group were lower than the control group (p = 0.012; 0.047). The mean disulfide concentration of the patient group was significantly higher than the control group (p = 0.025). SS/SH, SS/total SH, and SH/total SH ratios were significantly higher in the patient group than in the control group (p < 0.05). There was a positive correlation between the duration of the breasting of the patients and thiol concentrations (p = 0.000). In our study, we found increased oxidative stress and decreased antioxidant defense mechanisms in infants with AD. Dynamic thiol-disulfide balance in the patient group was weakened and the balance shifted towards the oxidative side. These results may shed light on etiopathogenesis of atopic dermatitis and be useful in the development of new therapeutic methods.

Oxidative Stress and Atopic Dermatitis

Atopic dermatitis is a common chronic/chronically relapsing inflammatory skin disease, with increasing worldwide prevalence. Etiopathogenesis is complex and multifactorial, with a mix of genetic, immunological and environmental aspects. Like in other chronic inflammatory diseases, oxidative stress plays an important pathogenetic role. We reviewed in vivo research studies on humans about oxidative stress and atopic dermatitis. Although sometimes contrasting, overall, they suggest that oxidative stress may have a significant role in atopic dermatitis, but our understanding is still incomplete, at least concerning in vivo data, because of limitations of available literature. Research consists of 33 papers published in 28 years, was not always performed on large study populations, represents a limited number of countries and ethnicities-not always in proportion to their size-and is scattered over multiple papers that, in the majority of cases, cannot be pooled and/or compared because many biomarkers were studied, in different tissues and with different methods. Further, larger studies appear warranted and necessary to shed more light on this aspect of atopic dermatitis, which is important not only to improve our understanding of this disease, but also for potential clinical and therapeutic implications.

Ultrafine particles and children's health: Literature review

The aim of this study was to review and synthesize the existing knowledge of the effects of ultrafine particles [UFPs] with a specific focus on children's health. An extensive literature search identified 16 studies fulfilling the criteria set for the review. One of the most important findings of the review was that, in general, there is an association between children's health and exposure to UFPs, especially among children with respiratory diseases, who commonly experience alterations in inflammatory biomarkers and deterioration in lung function as a result of UFP exposure. Notably, the health effects of UFPs are related to their ability to penetrate through different systems of the body due to their small size.

Urban particulate matter in air pollution penetrates into the barrier-disrupted skin and produces ROS-dependent cutaneous inflammatory response in vivo

BACKGROUND

Particulate matter (PM) is an integral part of air pollution, which is a mixture of particles suspended in the air. Recently, it has been reported that PM is associated with increased risks of skin diseases, especially atopic dermatitis in children. However, it is unclear if PM directly goes into the skin and what mechanisms are involved in response to PM.

OBJECTIVE

To see whether PM could penetrate into the barrier-disrupted skin, produce reactive oxygen species (ROS), and elicit an inflammatory response.

METHODS

We collected PMs during a winter in Seoul and used cultured keratinocytes for in vitro study and tape-stripped BALB/c mice for in vivo study.

RESULTS

Keratinocyte cytotoxicity increased in a dose-dependent manner by PM treatment. IL-8 and MMP-1 mRNA expression and protein levels were significantly increased compared to control by qPCR and ELISA, respectively. Cellular ROS production was increased by PM treatment, and antioxidant N-acetyl cysteine pretreatment prevented induction of inflammatory cytokines IL-8 and MMP-1. In PM-treated keratinocytes, electron-dense subcellular particles were observed by transmission electron microscopy. PM was observed inside hair follicles in both intact and barrier-disrupted skin in vivo. Additionally, intercellular penetration of PM was seen in the barrier-disrupted skin. Repeated PM application induced epidermal thickening and dermal inflammation with neutrophil infiltration. Finally, N-acetyl cysteine could ameliorate skin inflammation induced by PM application.

CONCLUSION

PM penetrates into the barrier-disrupted skin, causing inflammation, demonstrating detrimental effects in the skin.

Association of uremic pruritus in hemodialysis patients with the number of days of high mean 24-hour particulate matter with a diameter of <2.5 μm

Uremic pruritus (UP) is a common and incapacitating symptom in patients undergoing hemodialysis (HD). The pathogenesis of UP is multifactorial and complex. Particulate matter (PM), a major air pollutant, is a mixture of particles with various chemical compositions. PM is associated with several allergic diseases, including dermatitis. To assess the role of PM (PM with a diameter of <10 μm [PM₁₀] and PM with a diameter of <2.5 μm [PM_2.5]) and other clinical variables in UP in patients on HD, we recruited 866 patients on maintenance HD (MHD). We analyzed the number of days of mean 24-hour PM₁₀ ≥125 μg/m³/12 months (NDPM₁₀) or the number of days of mean 24-hour PM_2.5 ≥35 μg/m³/12 months (NDPM_2.5) exceeding the standard level in the past 12 months respectively to determine the association with UP. In a multivariate logistic regression, HD duration, serum ferritin levels, low-density lipoprotein (LDL) levels, and NDPM_2.5 ≥116 days/12 months were positively associated with UP. This cross-sectional study showed that the number of days on which the environmental PM_2.5 exceeds the standard level might be associated with UP in patients on MHD.

A longitudinal study of atrazine and 2,4-D exposure and oxidative stress markers among iowa corn farmers

Reactive oxygen species, potentially formed through environmental exposures, can overwhelm an organism's antioxidant capabilities resulting in oxidative stress. Long-term oxidative stress is linked with chronic diseases. Pesticide exposures have been shown to cause oxidative stress in vivo. We utilized a longitudinal study of corn farmers and non-farming controls in Iowa to examine the impact of exposure to the widely used herbicides atrazine and 2,4-dichlorophenoxyacetic acid (2,4-D) on markers of oxidative stress. 225 urine samples were collected during five agricultural time periods (pre-planting, planting, growing, harvest, off-season) for 30 farmers who applied pesticides occupationally and 10 controls who did not; all were non-smoking men ages 40-60. Atrazine mercapturate (atrazine metabolite), 2,4-D, and oxidative stress markers (malondialdehyde [MDA], 8-hydroxy-2'-deoxyguanosine [8-OHdG], and 8-isoprostaglandin-F_2α [8-isoPGF]) were measured in urine. We calculated β estimates and 95% confidence intervals (95%CI) for each pesticide-oxidative stress marker combination using multivariate linear mixed-effect models for repeated measures. Farmers had higher urinary atrazine mercapturate and 2,4-D levels compared with controls. In regression models, after natural log transformation, 2,4-D was associated with elevated levels of 8-OHdG (β = 0.066, 95%CI = 0.008-0.124) and 8-isoPGF (β = 0.088, 95%CI = 0.004-0.172). 2,4-D may be associated with oxidative stress because of modest increases in 8-OHdG, a marker of oxidative DNA damage, and 8-isoPGF, a product of lipoprotein peroxidation, with recent 2,4-D exposure. Future studies should investigate the role of 2,4-D-induced oxidative stress in the pathogenesis of human diseases. Environ. Mol. Mutagen. 58:30-38, 2017. © 2016 Wiley Periodicals, Inc.

A work group report on ultrafine particles (American Academy of Allergy, Asthma & Immunology): Why ambient ultrafine and engineered nanoparticles should receive special attention for possible adverse health outcomes in human subjects

Ultrafine particles (UFPs) are airborne particulates of less than 100 nm in aerodynamic diameter. Examples of UFPs are diesel exhaust particles, products of cooking, heating, and wood burning in indoor environments, and, more recently, products generated through the use of nanotechnology. Studies have shown that ambient UFPs have detrimental effects on both the cardiovascular and respiratory systems, including a higher incidence of atherosclerosis and exacerbation rate of asthma. UFPs have been found to alter in vitro and in vivo responses of the immune system to allergens and can also play a role in allergen sensitization. The inflammatory properties of UFPs can be mediated by a number of different mechanisms, including the ability to produce reactive oxygen species, leading to the generation of proinflammatory cytokines and airway inflammation. In addition, because of their small size, UFPs also have unique distribution characteristics in the respiratory tree and circulation and might be able to alter cellular function in ways that circumvent normal signaling pathways. Additionally, UFPs can penetrate intracellularly and potentially cause DNA damage. The recent advances in nanotechnology, although opening up new opportunities for the advancement of technology and medicine, could also lead to unforeseen adverse health effects in exposed human subjects. Further research is needed to clarify the safety of nanoscale particles, as well as the elucidation of the possible beneficial use of these particulates to treat disease.

Oxidative Stress in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disorder affecting many people especially young children. It is a disease caused by the combination of genetic predisposition, immune dysregulation, and skin barrier defect. In recent years, emerging evidence suggests oxidative stress may play an important role in many skin diseases and skin aging, possibly including AD. In this review, we give an update on scientific progress linking oxidative stress to AD and discuss future treatment strategies for better disease control and improved quality of life for AD patients.

Effects of ambient coarse, fine, and ultrafine particles and their biological constituents on systemic biomarkers: a controlled human exposure study

BACKGROUND

Ambient coarse, fine, and ultrafine particles have been associated with mortality and morbidity. Few studies have compared how various particle size fractions affect systemic biomarkers.

OBJECTIVES

We examined changes of blood and urinary biomarkers following exposures to three particle sizes.

METHODS

Fifty healthy nonsmoking volunteers, mean age of 28 years, were exposed to coarse (2.5-10 μm; mean, 213 μg/m3) and fine (0.15-2.5 μm; mean, 238 μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (< 0.3 μm; mean, 136 μg/m3) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks. Blood/urine samples were collected preexposure and 1 hr and 21 hr postexposure to determine blood interleukin-6 and C-reactive protein (inflammation), endothelin-1 and vascular endothelial growth factor (VEGF; vascular mediators), and malondialdehyde (lipid peroxidation); as well as urinary VEGF, 8-hydroxy-deoxy-guanosine (DNA oxidation), and malondialdehyde. Mixed-model regressions assessed pre- and postexposure differences.

RESULTS

One hour postexposure, for every 100-μg/m3 increase, coarse CAP was associated with increased blood VEGF (2.41 pg/mL; 95% CI: 0.41, 4.40) in models adjusted for O3, fine CAP with increased urinary malondialdehyde in single- (0.31 nmol/mg creatinine; 95% CI: 0.02, 0.60) and two-pollutant models, and ultrafine CAP with increased urinary 8-hydroxydeoxyguanosine in single- (0.69 ng/mg creatinine; 95% CI: 0.09, 1.29) and two-pollutant models, lasting < 21 hr. Endotoxin was significantly associated with biomarker changes similar to those found with CAPs.

CONCLUSIONS

Ambient particles with various sizes/constituents may influence systemic biomarkers differently. Endotoxin in ambient particles may contribute to vascular mediator changes and oxidative stress.

Allergy and asthma: Effects of the exposure to particulate matter and biological allergens

The prevalence of asthma and allergies including atopy has increased during the past decades, particularly in westernized countries. The rapid rise in the prevalence of such diseases cannot be explained by genetic factors alone. Rapid urbanization and industrialization throughout the world have increased air pollution and population exposures, so that most epidemiologic studies are focusing on possible links between air pollution and respiratory diseases. Furthermore, a growing body of evidence shows that chemical air pollution may interact with airborne allergens enhancing the risk of atopic sensitization and exacerbation of symptoms in sensitized subjects. These phenomena are supported by current in vitro and animal studies showing that the combined exposure to air pollutants and allergens may have a synergistic or additive effect on asthma and allergies, although there is an insufficient evidence about this link at the population level. Further research is needed in order to elucidate the mechanisms by which pollutants and biological allergens induce damage in exposed subjects. The abatement of the main risk factors for asthma and allergic diseases may achieve huge health benefits. Thus, it is important to raise awareness of respiratory allergies as serious chronic diseases which place a heavy burden on patients and on society as a whole.