The use of nasal lavage for objective measurement of irritant-induced nasal inflammation

Overview on the occurrence of microplastics in air and implications from the use of face masks during the COVID-19 pandemic

Environmental pollution from microplastics (MPs) in air is a matter of growing concern because of human health implications. Airborne MPs can be directly and continuously inhaled in air environments. Especially high MPs contributions can be found in indoor air due to the erosion and breakage of consumer, domestic and construction products, although there is little information available on their sources and concentrations and the risks they might pose. This is in part due to the fact that sampling and analysis of airborne MPs is a complex and multistep procedure where techniques used are not yet standardized. In this study, we provide an overview on the presence of MPs in indoor air, potential health impacts, the available methods for their sampling and detection and implications from the use of face masks during the COVID-19 pandemic.

Nasal lavages as a tool for monitoring exposure to organic pollutants

Exposure to air and dust pollutants can cause several adverse effects on human health. This study proposes the use of nasal lavages as a non-invasive sampling technique to determine in a direct way pollutant intake through inhalation. We evaluate the occurrence of compounds widely used in domestic products and construction materials (organophosphorus flame retardants (OPFR), phthalates, alkylphenols and bisphenol A), applied for pest control in cities (pesticides) and emitted through car exhausts (polycyclic aromatic hydrocarbons, PAHs) or smoking (nicotine). Contaminants were liquid-liquid extracted from nasal lavages and analysed using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). All 29 individuals inhabiting in Barcelona city had phthalates and bisphenol A at concentrations up to 31,300 ng mL^-1 for diethylhexyl phthalate (DEHP) and 118 ng mL^-1 for BPA. Individual PAHs, OPFR and alkylphenols had median values below their MQLs except for 2-ethylhexyldiphenyl phosphate (EHDPhP) with a median of 1.47 ng mL^-1. Nicotine was detected at the highest concentrations in all active smokers (median 2.16 ng mL^-1). Contrarily, pesticides were sporadically detected. Nasal lavages revealed to be an appropriate indicator likely to reflect exposure to dust and air contaminants.

Nasal PMN response to repeated challenge with endotoxin in healthy volunteers

RATIONALE

We have employed nasal challenge with lipopolysaccharide (LPS) followed by nasal lavage (NL) to experimentally induce and examine upper airway inflammation in human volunteers. It is unclear however whether adaptation within individuals occurs following repeated nasal challenge. This was a pilot study to determine if repeated nasal LPS challenge yields attenuation of markers of inflammation (primarily neutrophil response) in the NL fluid of healthy humans.

METHODS

We employed a 3-day nasal LPS challenge protocol with NL using a "split nose" design. The control and LPS nares received two consecutive day saline (0.9% saline/day) and LPS (2 µg LPS/day) challenges, respectively followed by an LPS (2 µg/day) challenge to each nare on Day 3. NL was performed immediately pre Day 1 challenges and 6-h post nasal LPS challenges on both Days 1 and 3. Markers of inflammation (PMNs/mg, cytokines) were assessed in NL and the inflammatory response to LPS (measured as the difference between pre and post challenge) was evaluated in both nares on Day 3 and compared to Day 1.

RESULTS

Significant (p < 0.05) blunting of the LPS-induced polymorphonuclear leukocyte (PMN) response was observed in the nare that received repeated LPS challenges as compared to the control nare (67.60  ±  22.39 vs. 157.8  ±  76.04 PMN/mg) and initial LPS challenge on Day 1 (121 ± 32 PMN/mg). Decreased soluble CD14 and significantly decreased interleukin-8 were also found in the repeat LPS-treated nare. In the LPS-treated nare, the blunted PMN response on Day 3 correlated well with the observed PMN response on Day 1 (r = 0.58, p = 0.02).

CONCLUSIONS

We show attenuation of PMN response to repeated LPS in the nasal airways in healthy humans. Effect of repeat endotoxin exposure prior to allergen delivery on local airway inflammation in both healthy and atopic subjects can be studied.

Circulating neutrophil CD14 expression and the inverse association of ambient particulate matter on lung function in asthmatic children

BACKGROUND

Identifying baseline inflammatory biomarkers that predict susceptibility to size-specific particulate matter (PM) independent of gaseous pollutants could help us better identify asthmatic subpopulations at increased risk for the adverse health effects of PM.

OBJECTIVE

To evaluate whether the association between lung function and exposure to ambient levels of PM less than 2.5 microm in diameter (PM2.5) (fine) and 10 to 2.5 microm in diameter (PM(10-2.5)) (coarse) in children with persistent asthma differed across baseline measures of inflammation and innate immune activation.

METHODS

We performed a panel study on a local population of 16 children with persistent asthma and evaluated daily pulmonary function (percentage of predicted peak expiratory flow and forced expiratory volume in 1 second) while concurrently measuring daily PM2.5 and PM(10-2.5) exposure from a central site in Chapel Hill, North Carolina. The children underwent a baseline medical evaluation that included assessment of several immunoinflammatory biomarkers in peripheral blood.

RESULTS

Children without measurable CD14 expression on circulating neutrophils had significantly reduced pulmonary function (forced expiratory volume in 1 second and peak expiratory flow) with each interquartile range (IQR) increase in PM2.5 (IQR = 8.5 microg/m3) and PM(10-2.5) (IQR = 4.1 microg/m3) concentration, unlike children with measurable CD14 expression (P < .001 for interaction).

CONCLUSIONS

Asthmatic children with muted surface expression of CD14 on circulating neutrophils may have a decreased capacity to respond to bacterial components of PM.

Nasal effects of a mixture of volatile organic compounds and their ozone oxidation products

OBJECTIVE

Our objective was to determine if low levels of a mixture of volatile organic compounds (VOCs) and their ozone (O3) oxidation products, similar to what might be found in "sick buildings," cause nasal irritation and inflammation under controlled exposure conditions.

METHODS

Healthy, nonsmoking women (n=130) completed 2-hour controlled exposures to VOCs, VOCs and O3, and a masked air "MA" control in random order at least 1 week apart. VOCs and O3 concentrations were approximately 25 mg/m and approximately 40 ppb, respectively. Nasal symptoms were rated before, during, and after exposure. Nasal lavage fluid was analyzed for polymorphonuclear cells, total protein, interleukin-6, and interleukin-8.

RESULTS

We found no significant differences in symptoms or markers of nasal inflammation between exposure conditions.

CONCLUSIONS

Results suggest that VOCs and their oxidation products may not cause acute nasal effects at low concentrations.

Are women more sensitive than men to 2-propanol and m-xylene vapours?

AIMS

To evaluate possible differences between men and women in acute health effects after controlled short term chamber exposure to vapours of two common organic solvents.

METHODS

Fifty six healthy volunteers (28 per sex) were exposed to 150 ppm 2-propanol, 50 ppm m-xylene, and clean air for two hours at rest. The subjects rated symptoms on a visual analogue scale before, during, and after the exposure. Blinking frequency was measured continuously during exposure. Pulmonary function, nasal swelling, inflammatory markers (lysozyme, eosinophilic cationic protein, myeloperoxidase, albumin) in nasal lavage and colour vision (Lanthony D-15 desaturated panel) were measured before and at 0 and 3 hours after the exposure.

RESULTS

There were no significant sex differences in response to solvent exposure with respect to blinking frequency, lung diffusing capacity, nasal area and volume, inflammatory markers in nasal lavage, and colour vision. Increased symptoms were rated by both sexes for nearly all 10 questions during exposure to 2-propanol or m-xylene, most increases being significant at one time point at least. The rating of "discomfort in the throat or airways" increased more in women during exposure to 2-propanol or m-xylene. During exposure to 2-propanol the rating of "fatigue" was more increased in men after one hour, but more increased in women after two hours of exposure. With regard to pulmonary function, women had small but significant decreases in FVC, FEV(1)/FVC, and FEF(75) three hours after exposure to m-xylene, but only the decrease in FVC was significantly different from that in men.

CONCLUSION

Our results suggest that women are slightly more sensitive than men to the acute irritative effects of 2-propanol and m-xylene vapours.

Nasal albumin in a population exposed for the first time to urban pollution

BACKGROUND

High levels of albumin in some biological fluids are generally associated with abnormal process of permeation during an inflammatory response. In some cases, the nasal albumin levels can be used as an indirect molecular marker of epithelial damage.

METHODS

We carried out an evaluation study of nasal albumin from a population (14 volunteers), exposed for 15 days to high urban pollution (O(3) 10.644 ppm/h average 10.2 h/day) in Mexico City for the first time, and when they returned to their original non-polluted city (Veracruz, State of Veracruz, Mexico) 13 days later. The nasal albumin samples were fractionated by gel electrophoresis techniques, and albumin determination analyses were done by gel scanning. The densitometry values obtained from the albumin-stained bands were compared with an internal standard and the average values compared with other groups used as reference, under conditions of non-polluted and polluted cities.

RESULTS

Our findings showed in the group exposed to pollution for the first time a significant increment 2 days after entering Mexico City urban pollution. They, subsequently, had a progressive recovery 4 days later up to day 13 in their original place of residence. The reference groups for comparison were from a non-polluted city (at sea level on the Pacific Ocean) Manzanillo, Colima, Mexico, and a very polluted urban metropolis (Mexico City). The group showed a significant difference of protein levels about 2.5 higher apparently at the expense of albumin. These populations were permanent residents of environmental conditions we wanted to evaluate. Our approach was to monitor quantitatively the time course of the change of a biochemical parameter in normal mucus from a population never exposed to Mexico City urban pollution.

CONCLUSIONS

Our conclusions from this study point out that pollution causes diverse mucosal damage that can be followed by biochemical monitoring.

Allergen provocation augments endotoxin-induced nasal inflammation in subjects with atopic asthma

BACKGROUND

Recent epidemiologic and in vivo studies have suggested that inhaled endotoxin plays an important role in asthma pathogenesis.

OBJECTIVE

The present study examines the effect of nasal allergen provocation on subsequent endotoxin challenge in subjects with atopic asthma.

METHODS

By using a split-nose randomized crossover design, individual nares of 12 asthmatic subjects underwent challenge and lavage as follows. Immediately after a baseline nasal lavage, one nares received normal saline, and the other received dust mite antigen. Four hours later, both nares were exposed to either saline or endotoxin. Dust mite antigen (Dermatophagoides farinae) and endotoxin (Escherichia coli 026:B6) doses were 100 AU and 1000 ng, respectively. Postchallenge lavages were done at 8 and 24 hours after the initial challenge. The subjects then returned a minimum of 3 weeks later for crossover to the study arm. Nasal lavage fluid was analyzed for total and differential cell counts, IL-8, IL-6, intercellular adhesion molecule 1, GM-CSF, eosinophil cationic protein, myeloperoxidase, and soluble CD14.

RESULTS

A significant increase in the total inflammatory cell count was seen at 8 hours for the dust mite/endotoxin exposure compared with the saline/saline and saline/endotoxin exposures. Differential cell counts revealed a similar neutrophilic and eosinophilic inflammation for the dust mite/endotoxin exposure at 8 hours.

CONCLUSIONS

These data demonstrate an interaction between allergen and endotoxin exposure in asthmatic subjects, suggesting that a prior allergen challenge significantly augments the endotoxin-induced inflammation. Moreover, these data provide further evidence that concomitant exposure to allergen and endotoxin may be an important factor in asthma pathogenesis.

Indoor air pollutants in schools: nasal patency and biomarkers in nasal lavage

BACKGROUND

There is growing concern about the respiratory health aspects of the indoor air quality in schools.

METHODS

A standardized investigation, including nasal lavage (NAL), measurement of the nasal cavity by acoustic rhinometry, and hygienic measurements of airborne pollutants, was performed in classrooms, outside the pollen season. All 279 school personnel working in the main buildings of 12 randomly selected primary schools in an urban community in central Sweden (Uppsala) were invited to enroll in the study; 234 (84%) participated. Eosinophil cationic protein (ECP), myeloperoxidase (MPO), lysozyme, and albumin were analyzed in NAL fluid. Crude statistical analysis, as well as multiple regression analysis, was performed, controlling for room temperature, age, sex, current smoking, and a history of atopy.

RESULTS

Most classrooms (83%) did not meet the Swedish ventilation standards. A lower degree of nasal patency was found at higher concentrations of respirable dust, nitrogen dioxide (NO2), formaldehyde, and total molds, and in the presence of Aspergillus spp. in the classroom air. The most consistent findings were observed for formaldehyde, NO2, and Aspergillus spp., related to both decreased nasal patency and increase of ECP and lysozyme in NAL. The presence of yeast was associated with an increase of ECP and lysozyme in NAL, but was not related to nasal patency.

CONCLUSIONS

Ventilation flow was below current hygienic standards in the classrooms. Air pollutants in the classroom air may influence nasal patency and inflammatory response in the nasal mucosa.