Inflammatory response after inhalation of bacterial endotoxin assessed by the induced sputum technique

Bioaerosol-induced in vitro activation of toll-like receptors and inflammatory biomarker expression in waste workers

PURPOSE

Occupational exposure to bioaerosols during waste handling remains a health concern for exposed workers. However, exposure-related health effects and underlying immunological mechanisms are still poorly described.

METHODS

The present study assessed the inflammatory potential of work-air samples (n = 56) in vitro and investigated biomarker expression in exposed workers (n = 69) compared to unexposed controls (n = 25). These quantitative results were compared to self-reported health conditions.

RESULTS

Personal air samples provoked an activation of TLR2 and TLR4 HEK reporter cells in one-third of all samples, indicating that the work environment contained ligands capable of inducing an immune response in vitro. Monocyte levels, as well as plasma biomarker levels, such as IL-1Ra, IL-18 and TNFα were significantly higher in exposed workers, compared to the control group when confounding factors such as BMI, sex, age and smoking habits were accounted for. Furthermore, a significant exposure-related increase in midweek IL-8 levels was measured among exposed workers. Tendencies of increased prevalence of health effects of the respiratory tract were identified in exposed workers.

CONCLUSION

Inhalable dust provoked TLR activation in vitro, indicating that an exposure-related immune response may be expected in susceptible workers. However, despite significant differences in inflammatory plasma biomarker levels between exposed and unexposed workers, prevalence of self-reported health effects did not differ between the groups. This may be due to the healthy worker effect, or other factors such as adequate use of personal protective respiratory devices or adaptation to the work environment with reduced activation of the immune system.

Prospects of Inhaled Phage Therapy for Combatting Pulmonary Infections

With respiratory infections accounting for significant morbidity and mortality, the issue of antibiotic resistance has added to the gravity of the situation. Treatment of pulmonary infections (bacterial pneumonia, cystic fibrosis-associated bacterial infections, tuberculosis) is more challenging with the involvement of multi-drug resistant bacterial strains, which act as etiological agents. Furthermore, with the dearth of new antibiotics available and old antibiotics losing efficacy, it is prudent to switch to non-antibiotic approaches to fight this battle. Phage therapy represents one such approach that has proven effective against a range of bacterial pathogens including drug resistant strains. Inhaled phage therapy encompasses the use of stable phage preparations given via aerosol delivery. This therapy can be used as an adjunct treatment option in both prophylactic and therapeutic modes. In the present review, we first highlight the role and action of phages against pulmonary pathogens, followed by delineating the different methods of delivery of inhaled phage therapy with evidence of success. The review aims to focus on recent advances and developments in improving the final success and outcome of pulmonary phage therapy. It details the use of electrospray for targeted delivery, advances in nebulization techniques, individualized controlled inhalation with software control, and liposome-encapsulated nebulized phages to take pulmonary phage delivery to the next level. The review expands knowledge on the pulmonary delivery of phages and the advances that have been made for improved outcomes in the treatment of respiratory infections.

Human lipopolysaccharide models provide mechanistic and therapeutic insights into systemic and pulmonary inflammation

Inflammation is a key feature in the pathogenesis of sepsis and acute respiratory distress syndrome (ARDS). Sepsis and ARDS continue to be associated with high mortality. A key contributory factor is the rudimentary understanding of the early events in pulmonary and systemic inflammation in humans, which are difficult to study in clinical practice, as they precede the patient's presentation to medical services. Lipopolysaccharide (LPS), a constituent of the outer membrane of Gram-negative bacteria, is a trigger of inflammation and the dysregulated host response in sepsis. Human LPS models deliver a small quantity of LPS to healthy volunteers, triggering an inflammatory response and providing a window to study early inflammation in humans. This allows biological/mechanistic insights to be made and new therapeutic strategies to be tested in a controlled, reproducible environment from a defined point in time. We review the use of human LPS models, focussing on the underlying mechanistic insights that have been gained by studying the response to intravenous and pulmonary LPS challenge. We discuss variables that may influence the response to LPS before considering factors that should be considered when designing future human LPS studies.

Occupational Exposure to Endotoxin along a Municipal Scale Fecal Sludge Collection and Resource Recovery Process in Kigali, Rwanda

Background: Little is known about occupational exposures that occur along fecal sludge collection and resource recovery processes. This study characterizes inhaled endotoxin exposure to workers of a municipal scale fecal sludge-to-fuel processes in Kigali, Rwanda. Methods: Forty-two task-based air samples were collected from workers in five tasks along the fecal sludge collection and resource recovery process. Samples were processed for endotoxin using the limulus amebocyte lysate (LAL) test. To account for exposure variability and compare measured concentrations to established exposure limits, we used Monte Carlo modeling methods to construct distributions representing full eight-hour (8-h) exposures to endotoxin across eight exposure scenarios. Results: Geometric mean (GM) endotoxin concentrations in task-based samples ranged from 11–3700 EU/m³ with exposure concentrations increasing as the dryness of the fecal sludge increased through processing. The thermal dryer task had the highest endotoxin concentrations (GM = 3700 EU/m³) and the inlet task had the lowest (GM = 11 EU/m³). The geometric means (GM) of modeled 8-h exposure concentrations were between 6.7–960 EU/m³ and highest for scenarios which included the thermal dryer task in the exposure scenario. Conclusions: Our data suggest the importance of including worker exposure considerations in the design of nascent fecal sludge management processes. The methods used in this study combine workplace sampling with stochastic modeling and are useful for exposure assessment in resource constrained contexts.

Microbial contamination of coffee during postharvest on farm processing: A concern for the respiratory health of production workers

Coffee workers respiratory health problems, found to be associated with dust exposure in the coffee factories, but the content of the dust is not well known. A cross-sectional survey was conducted to assess the microbial contamination of coffee in dry and wet coffee process, from four farms in two regions of Ethiopia. A total of 36 samples of coffee were collected for laboratory investigation. The microbial load in the dry process ranged from 6.9 × 10² to 7.2 × 10⁵ colony forming units (CFU)/mL while the microbial load in wet process ranged from 2.5 × 10² to 4.6 × 10⁵ CFU/mL. The results indicate the presence of gram negative bacteria in dried and stored beans from both the wet and dry process. During further coffee processing possible release of endotoxin from coffee contaminated by gram negative bacteria might affect coffee workers respiratory health. Further studies are required to assess the relation between bacterial contamination of coffee and endotoxin level in coffee factories.

Inhalation of concentrated PM2.5 from Mexico City acts as an adjuvant in a guinea pig model of allergic asthma

Exposure to Particulate Matter (PM) could function as an adjuvant depending on the city of origin in mice allergic asthma models. Therefore, our aim was to determine whether inhalation of fine particles (PM2.5) from Mexico City could act as an adjuvant inducing allergic sensitization and/or worsening the asthmatic response in guinea pig, as a suitable model of human asthma. Experimental groups were Non-Sensitized (NS group), sensitized with Ovalbumin (OVA) plus Aluminum hydroxide (Al(OH)3) as adjuvant (S + Adj group), and sensitized (OVA) without adjuvant (S group). All the animals were exposed to Filtered Air (FA) or concentrated PM2.5 (5 h/daily/3 days), employing an aerosol concentrator system, PM2.5 composition was characterized. Lung function was evaluated by barometric plethysmography (Penh index). Inflammatory cells present in bronchoalveolar lavage were counted as well as OVA-specific IgG1 and IgE were determined by ELISA assay. Our results showed in sensitized animals without Al(OH)3, that the PM2.5 exposure (609 ± 12.73 μg/m3) acted as an adjuvant, triggering OVA-specific IgG1 and IgE concentration. Penh index increased ∼9-fold after OVA challenge in adjuvant-sensitized animals as well as in S + PM2.5 group (∼6-fold), meanwhile NS + FA and S + FA lacked response. S + Adj + PM2.5 group showed an increase significantly of eosinophils and neutrophils in bronchoalveolar lavage. PM2.5 composition was made up of inorganic elements and Polycyclic Aromatic Hydrocarbons, as well as endotoxins and β-glucan, all these components could act as adjuvant. Our study demonstrated that acute inhalation of PM2.5 acted as an adjuvant, similar to the aluminum hydroxide effect, triggering allergic asthma in a guinea pig model. Furthermore, in sensitized animals with aluminum hydroxide an enhancing influence of PM2.5 exposure was observed as specific-hyperresponsiveness to OVA challenge (quickly response) and eosinophilic and neutrophilic airway inflammation. Fine particles from Mexico City is a complex mix, which play a significant role as adjuvant in allergic asthma.

Role of lipopolysaccharide (LPS) in asthma and other pulmonary conditions

Endotoxin significantly contaminates house dust and is an enhancing factor for asthma severity. Natural exposure to endotoxin in early life could influence immune development and protect from the risk of developing atopy. This article will focus on published data showing that home environmental contamination by endotoxin can participate in chronic airways diseases, in particular asthma.

Review: Endotoxin in the environment — exposure and effects

This review deals with endotoxin in the environment and its relation to disease among exposed persons. Data are presented on levels of endotoxin in different environments with maximum values of several μg/m3. The cellular reactions of importance for inhalation exposure effects are attachment to lipopolysaccharide binding protein, CD14 cell surface protein and TLR-4 receptors. The internalisation of endotoxin in macrophages and endothelial cells results in local production of inflammatory cytokines with subsequent migration of inflammatory cells into the lung and the penetration of cytokines into the blood. These events orchestrate clinical effects in terms of toxic pneumonitis, airways' inflammation and systemic symptoms. Inhalation challenges with pure endotoxin and field studies confirm the relation between these effects and exposure to dusts containing endotoxin. It is possible that polymorphism in genes determining endotoxin reactivity, particularly TLR-4, influences the risk for disease after environmental exposures. Some data suggest that the inflammation caused by inhaled endotoxin may decrease the risk for atopic sensitisation among children and lung cancer among workers exposed to organic dust. Additional research is needed to clarify the role of other environmental agents that are present in connection with endotoxin, particularly (1→3)-β-D-glucan from mold cell walls.

Endotoxin induces leukocyte transmigration and changes in permeability of the airway epithelium via protein-kinase C and extracellular regulated kinase activation

Lipopolysaccharide (LPS) endotoxin of Gram-negative bacteria compromises the integrity of the airway epithelial barrier and initiates migration of leukocytes across the epithelium. The goal of the present study was to identify the role of extracellular regulated kinase (ERK1/2) transduction pathways in these processes. The first aim was to determine whether LPS induces ERK1/2 activation and changes in epithelial permeabilityin epithelial cells alone or only in the presence of immune cells. The second aim was to determine whether the changes in the epithelial permeability were diminished by ERK1/2 blockade. The third aim was to investigatethe role of protein kinase C (PKC) activation as an upstream event in activation of ERK1/2. In vitro 20 μg/ml LPS challenge reduced epithelial barrier function, and induced ERK1/2 phosphorylation in primary cultures of bovine tracheal epithelium and in the transformed human airway epithelial cell line, Calu-3. LPS initiated migration of neutrophil-like and monocyte-like transformed HL-60 cell across sheets of Calu-3 cells. The migration rate and the associated changes in the electrical resistance, permeability to albumin, and ERK1/2 phosphorylation were all blocked by calphostin C, the specific blocker of PKC and by PD98059 (2'-amino-3'methoxyflavone), a selective cell-permeable inhibitor of MAP kinase kinase. In rats, in vivo perfusion of the lumen of an isolated segment of trachea with LPS (0.1 mg/ml) initiated migration of neutrophils and increased the permeability to albumin. Again, these effects were markedly inhibited by PD98059 and calphostin C (by > 50%). We conclude that epithelial ERK1/2 is activated by endotoxin via PKC and is an important pathway in regulation of epithelial permeability.

High throughput genomic sequencing of bioaerosols in broiler chicken production facilities

Chronic inhalation exposure to agricultural dust promotes the development of chronic respiratory diseases among poultry workers. Poultry dust is composed of dander, chicken feed, litter bedding and microbes. However, the microbial composition and abundance has not been fully elucidated. Genomic DNA was extracted from settled dust and personal inhalable dust collected while performing litter sampling or mortality collection tasks. DNA libraries were sequenced using a paired‐end sequencing‐by‐synthesis approach on an Illumina HiSeq 2500. Sequencing data showed that poultry dust is predominantly composed of bacteria (64–67%) with a small quantity of avian, human and feed DNA (< 2% of total reads). Staphylococcus sp. AL1, Salinicoccus carnicancri and Lactobacillus crispatus were the most abundant bacterial species in personal exposure samples of inhalable dust. Settled dust had a moderate relative abundance of these species as well as Staphylococcus lentus and Lactobacillus salivarius. There was a statistical difference between the microbial composition of aerosolized and settled dust. Unlike settled dust composition, aerosolized dust composition had little variance between samples. These data provide an extensive analysis of the microbial composition and relative abundance in personal inhalable poultry dust and settled poultry dust.

Effect of deployment time on endotoxin and allergen exposure assessment using electrostatic dust collectors

The electrostatic dust collector (EDC) is a passive dust sampling device for exposure assessment of airborne endotoxin and possibly allergens. EDCs consist of a non-conducting plastic folder holding two or four electrostatic cloths of defined area. The sampling time needed to achieve detectable and reproducible loading for bioaerosols has not been systematically evaluated. Thus, in 15 Iowa farm homes EDCs were deployed for 7-, 14-, and 28-day sampling periods to determine if endotoxin and allergens could be quantified and if loading rates were uniform over time, i.e. if loads doubled from 7 to 14 days or 14 to 28 days and quadrupled from 7 to 28 days. Loadings between left and right paired EDC cloths were not significantly different and were highly correlated for endotoxin, total protein, and cat (Fel d1), dog (Can f1), and mouse (Mus m1) allergens (P < 0.001). EDCs performed especially well for endotoxin sampling with close agreement between paired samples (Pearson r = 0.96, P < 0.001). Endotoxin loading of the EDCs doubled from 7- to 14-day deployments as hypothesized although the loading rate decreased from 14 to 28 days of sampling with only a 1.38-fold increase. Allergen exposure assessment using EDCs was overall less satisfactory. Although there was reasonable agreement between paired samples, only exposures to cat, dog, and mouse allergens were reliable and these only at the longer deployment times.

Adverse health problems among municipality workers in alexandria (egypt)

BACKGROUND

Solid waste management has emerged as an important human and environmental health issue. Municipal solid waste workers (MSWWs) are potentially exposed to a variety of occupational biohazards and safety risks. The aim of this study was to describe health practices and safety measures adopted by workers in the main municipal company in Alexandria (Egypt) as well as the pattern of the encountered work related ill health.

METHODS

A cross-sectional study was conducted between January and April 2013. We interviewed and evaluated 346 workers serving in about 15 different solid waste management activities regarding personal hygiene, the practice of security and health care measures and the impact of solid waste management.

RESULTS

Poor personal hygiene and self-care, inadequate protective and safety measures for potentially hazardous exposure were described. Impact of solid waste management on health of MSWWs entailed high prevalence of gastrointestinal, respiratory, skin and musculoskeletal morbidities. Occurrence of accidents and needle stick injuries amounted to 46.5% and 32.7% respectively. The risk of work related health disorders was notably higher among workers directly exposed to solid waste when compared by a group of low exposure potential particularly for diarrhea (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.2-3.8), vomiting (OR = 2.7, 95% CI = 1.1-6.6), abdominal colic (OR = 1.9, 95% CI = 1.1-3.2), dysentery (OR = 3.6, 95% CI = 1.3-10), dyspepsia (OR = 1.8, 95% CI = 1.1-3), low back/sciatic pain (OR = 3.5, 95% CI = 1.8-7), tinnitus (OR = 6.2, 95% CI = 0.3-122) and needle stick injury (OR = 3.4, 95% CI = 2.1-5.5).

CONCLUSIONS

Workers exposed to solid waste exhibit significant increase in risk of ill health. Physician role and health education could be the key to assure the MSWWs health safety.

LPS-induced lung inflammation in marmoset monkeys - an acute model for anti-inflammatory drug testing

Increasing incidence and substantial morbidity and mortality of respiratory diseases requires the development of new human-specific anti-inflammatory and disease-modifying therapeutics. Therefore, new predictive animal models that closely reflect human lung pathology are needed. In the current study, a tiered acute lipopolysaccharide (LPS)-induced inflammation model was established in marmoset monkeys (Callithrix jacchus) to reflect crucial features of inflammatory lung diseases. Firstly, in an ex vivo approach marmoset and, for the purposes of comparison, human precision-cut lung slices (PCLS) were stimulated with LPS in the presence or absence of the phosphodiesterase-4 (PDE4) inhibitor roflumilast. Pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-α) and macrophage inflammatory protein-1 beta (MIP-1β) were measured. The corticosteroid dexamethasone was used as treatment control. Secondly, in an in vivo approach marmosets were pre-treated with roflumilast or dexamethasone and unilaterally challenged with LPS. Ipsilateral bronchoalveolar lavage (BAL) was conducted 18 hours after LPS challenge. BAL fluid was processed and analyzed for neutrophils, TNF-α, and MIP-1β. TNF-α release in marmoset PCLS correlated significantly with human PCLS. Roflumilast treatment significantly reduced TNF-α secretion ex vivo in both species, with comparable half maximal inhibitory concentration (IC(50)). LPS instillation into marmoset lungs caused a profound inflammation as shown by neutrophilic influx and increased TNF-α and MIP-1β levels in BAL fluid. This inflammatory response was significantly suppressed by roflumilast and dexamethasone. The close similarity of marmoset and human lungs regarding LPS-induced inflammation and the significant anti-inflammatory effect of approved pharmaceuticals assess the suitability of marmoset monkeys to serve as a promising model for studying anti-inflammatory drugs.

Pneumoproteins in sewage workers exposed to sewage dust

Purpose

The association between exposure to bacteria and endotoxins in sewage dust and the serum concentrations of pneumoproteins in sewage treatment plant workers were studied.

Methods

Forty-four workers from eight sewage treatment plants and 38 reference workers participated in the study. Microbial aerosol was collected by personal inhalable samplers. The concentrations of bacteria and endotoxins were determined by fluorescence microscopy and the Limulus assay, respectively. Pneumoproteins (Clara cell protein: CC16, and Surfactant proteins A and D: SP-A, SP-D) were determined by ELISA in blood samples collected post-shift.

Results

The exposure to dust ranged from 0.02 to 9.3 (geometric mean (GM) 0.3 mg/m³, of bacteria from 0.3 to 4,900 × 10³ (GM 27 × 10³) cells/m³ and endotoxins from 1 to 3,160 (GM 28) EU/m³. The exposed workers had lower CC16 [arithmetic mean (AM) 4.9 ng/ml] compared to the referents (AM 6.4 ng/ml, p < 0.01). No significant difference was observed for SP-D and SP-A. Exposure to bacteria was positively associated with CC16 (p < 0.05) and SP-D (p < 0.05), adjusting for possible confounders.

Conclusions

This study showed that exposed workers had lower serum concentration of CC16 as compared to the referents, which may reflect a long-term effect on secretion of these pneumoproteins. The positive association between exposure to bacteria and the serum concentrations of CC16 and SP-D may be explained by a transient increased permeability of the lung–blood barrier.

Definitions and classification of work-related asthma

The workplace can trigger or induce asthma and cause the onset of different types of work-related asthma (WRA). Based on current knowledge of clinical features, pathophysiologic mechanisms, and evidence supporting a causal relationship, the following conditions should be distinguished in the spectrum of WRA: (1) immunologic occupational asthma (OA), (2) nonimmunologic OA, (3) work-exacerbated asthma, and (4) variant syndromes, including eosinophilic bronchitis, potroom asthma, and asthmalike disorders caused by organic dusts. The rationale, issues, and controversies relating to this approach are critically reviewed to stimulate the development of a consensus on operational definitions of the various phenotypes of WRA.

A water-damaged home and health of occupants: a case study

A family of five and pet dog who rented a water-damaged home and developed multiple health problems. The home was analyzed for species of mold and bacteria. The diagnostics included MRI for chronic sinusitis with ENT and sinus surgery, and neurological testing for neurocognitive deficits. Bulk samples from the home, tissue from the sinuses, urine, nasal secretions, placenta, umbilical cord, and breast milk were tested for the presence of trichothecenes, aflatoxins, and Ochratoxin A. The family had the following diagnosed conditions: chronic sinusitis, neurological deficits, coughing with wheeze, nose bleeds, and fatigue among other symptoms. An infant was born with a total body flare, developed multiple Cafe-au-Lait pigmented skin spots and diagnoses with NF1 at age 2. The mycotoxins were detected in bulk samples, urine and nasal secretions, breast milk, placenta, and umbilical cord. Pseudomonas aueroginosa, Acinetobacter, Penicillium, and Aspergillus fumigatus were cultured from nasal secretions (father and daughter). RT-PCR revealed A. fumigatus DNA in sinus tissues of the daughter. The dog had 72 skin lesions (sebaceous glands and lipomas) from which trichothecenes and ochratoxin A. were detected. The health of the family is discussed in relation to the most recent published literature regarding microbial contamination and toxic by-products present in water-damaged buildings.

Inhalation of LPS induces inflammatory airway responses mimicking characteristics of chronic obstructive pulmonary disease

AIM

Inhalation of lipopolysaccharide (LPS) produces both systemic and pulmonary inflammatory responses. The aim of this study was to further characterize the response to LPS in order to develop a human model suitable for early testing of drug candidates developed for the treatment for chronic obstructive pulmonary disease (COPD).

MATERIALS

Blood and induced sputum were obtained 4, 24 and 48 h following inhalation of saline and LPS (5 and 50 μg). Blood was analysed for C-reactive protein (CRP), α(1)-antitrypsin and neutrophils/leucocytes, and sputum was analysed for biomarkers of neutrophil inflammation and remodelling activities, i.e. neutrophil elastase (NE) protein/activity and α(1)-antitrypsin. Levels of tumour necrosis factor-α (TNFα) were measured in both blood and sputum. Urine was collected 0-24 and 24-48 h postchallenge, and desmosine, a biomarker of elastin degradation, was measured.

RESULTS

Lipopolysaccharide inhalation induced dose-dependent flu-like symptoms and increases in plasma CRP and α(1)-antitrypsin as well as increases in blood neutrophil/leucocyte numbers. Furthermore, LPS produced increases in sputum TNFα and sputum NE activity. Urine levels of desmosine were unaffected by the LPS challenge. All subjects recovered 48 h postchallenge, and indices of inflammatory activity were significantly lower at this observation point cf 24 h postchallenge.

CONCLUSION

Inhalation of LPS in healthy volunteers can be used as a safe and stable model of neutrophil inflammation. Blood/plasma and sputum indices can be employed to monitor the response to LPS. We suggest that this model may be used for initial human studies of novel COPD-active drugs.

Occupational exposure to bacterial single cell protein induces inflammation in lung and blood

Bacterial single cell protein (BSCP) is used as a protein enrichment in livestock and fish feed, and is extracted from dried bacterial mass. In the production of BSCP, workers are exposed to organic dust containing high levels of endotoxins that may induce acute airway inflammation. However, the long term effect on the airways of such exposure is not known, and we have examined inflammatory markers in induced sputum and blood among BSCP exposed workers. We included 21 non-smoking production workers (age 31-42 (range; mean 35)) without respiratory symptoms and 21 healthy non-exposed references (age 21-52 (range; mean 34)). Airborne endotoxin concentrations were measured, and induced sputum samples and blood samples were collected from the workers and non-exposed references. The airborne endotoxin concentration measured in inhaled air during the work shift was 430 EU/m(3) (50-2000) (median (range)). The percentage of neutrophils in induced sputum was 79% (66-93) (median (25th-75th percentiles)) and 31% (25-45) (p < 0.001) for operators and references, respectively. Protein analysis in induced sputum supernatant showed significantly elevated levels of interleukins IL-1beta and IL-12 (p < 0.05), while blood analysis showed significantly elevated levels of PDGF-BB (platelet-derived growth factor-BB) and RANTES (regulated upon activation normally T cell expressed and secreted) (p < 0.05). Workers exposed to BSCP had an airway inflammation characterized by a high level of neutrophils. However, only a few cytokines were elevated in lung and blood, which could imply low inflammatory activity suggestive of possible adaptation mechanisms due to daily exposure to BSCP, or that the inflammation reaction was a dose-related response occurring at higher levels.

Noninvasive methods for assessment of airway inflammation in occupational settings

The present document is a consensus statement reached by a panel of experts on noninvasive methods for assessment of airway inflammation in the investigation of occupational respiratory diseases, such as occupational rhinitis, occupational asthma, and nonasthmatic eosinophilic bronchitis. Both the upper and the lower airway inflammation have been reviewed and appraised reinforcing the concept of 'united airway disease' in the occupational settings. The most widely used noninvasive methods to assess bronchial inflammation are covered: induced sputum, fractional exhaled nitric oxide (FeNO) concentration, and exhaled breath condensate. Nasal inflammation may be assessed by noninvasive approaches such as nasal cytology and nasal lavage, which provide information on different aspects of inflammatory processes (cellular vs mediators). Key messages and suggestions on the use of noninvasive methods for assessment of airway inflammation in the investigation and diagnosis of occupational airway diseases are issued.

Modeling human health risks of airborne endotoxin in homes during the winter and summer seasons

Endotoxin, a component of gram-negative bacterial cell walls, is a pro-inflammatory agent that induces local and systemic inflammatory responses in normal subjects which can contribute to the risk of developing asthma and chronic obstructive lung diseases. A probabilistic approach linking models of exposure, internal dosimetry, and health effects was carried out to quantitatively assess the potential inhalation risk of airborne endotoxin in homes during the winter and summer seasons. Combining empirical data and modeling results, we show that the half-maximum effect of the endotoxin dose (ED50) was estimated to be 707.9 (95% confidence interval (CI): 308.8-1287.0) endotoxin units (EU) for body temperature change, 481.8 (95% CI: 333.2-630.3) EU for elevation of neutrophils, and 1174.5 (95% CI: 816.0-1532.9) EU for elevation of the cytokine, interleukin-6. Our study also suggests that airborne endotoxin in homes may pose potential risks, and a higher risk for elevation of neutrophils and cytokine interleukin-6 appeared in winter season than in summer. Our study offers a risk-management framework for discussion of future studies of human respiratory exposure to airborne endotoxin.

Dose responses to inhalation of endotoxin, hay dust suspension and Aspergillus fumigatus extract in horses as measured by levels and activation of matrix metalloproteinase-9

REASONS FOR PERFORMING STUDY

Airway matrix metalloproteinases (MMPs) increase after endotoxin (LPS) exposure, but there are no reports describing dose-dependent increases or activation following exposure.

OBJECTIVES

To study matrix metalloproteinase-9 (MMP-9) and -2 (MMP-2) responses in bronchoalveolar lavage fluid (BALF) from heaves-susceptible and control horses following inhalation of hay dust suspension (HDS), LPS and Aspergillus fumigatus extract (AFE).

METHODS

Heaves-susceptible (n = 7) and control (n = 6) horses received inhalation challenges with 3 different doses of HDS and LPS. Heaves-susceptible horses (n = 6) also received 3 different doses of AFE and one dose of AFE depleted of endotoxin (AFE-LPS). BALF collected following inhalation challenges was analysed using gelatin zymography. Gelatinolytic bands were identified as complex, pro-MMP-9, active MMP-9, pro-MMP-2 and active MMP-2 based on molecular weights.

RESULTS

Each challenge substance induced a dose-dependent elevation in gelatinolytic activity. The dose-dependency was most evident for pro-MMP-9 and total MMP-9 levels in heaves-susceptible horses following LPS challenges.

CONCLUSIONS

There is a dose-dependent elevation in MMP-9 in BALF of heaves-susceptible and control horses following inhalation challenge with organic dust and some of its components, elevation being more marked in heaves-susceptible horses. Organic dust components vary in their pro-inflammatory potential.

POTENTIAL RELEVANCE

This study supports the role of MMPs in the pathogenesis of heaves and highlights the potential value of protease inhibitors in attenuating the airway inflammatory response to inhaled organic dust.

Endotoxin exposure and inflammation markers among agricultural workers in Colorado and Nebraska

The adverse respiratory effects of agricultural dust inhalation are mediated in part by endotoxin, a constituent of gram-negative bacterial cell walls. This study quantified personal work-shift exposures to inhalable dust, endotoxin, and its reactive 3-hydroxy fatty acid (3-OHFA) constituents among workers in grain elevators, cattle feedlots, dairies, and on corn farms. Exposures were compared with post-work-shift nasal lavage fluid inflammation markers and respiratory symptoms. Breathing-zone personal air monitoring was performed over one work shift to quantify inhalable dust (Institute of Medicine samplers), endotoxin (recombinant factor C [rFC] assay), and 3-OHFA (gas chromatography/mass spectrometry). Post-shift nasal lavage fluids were assayed for polymorphonuclear neutrophils (PMN), myeloperoxidase (MPO), interleukin 8 (IL-8), albumin, and eosinophilic cation protein (ECP) concentrations. The geometric mean (GSD) of endotoxin exposure (rFC assay) among the 125 male participants was 888 +/- (6.5) EU/m(3), and 93% exceeded the proposed exposure limit (50 EU/m(3)). Mean PMN, MPO, albumin, and ECP levels were two- to threefold higher among workers in the upper quartile of 3-OHFA exposure compared to the lowest exposure quartile. Even numbered 3-OHFA were most strongly associated with nasal inflammation. Symptom prevalence was not elevated among exposed workers, possibly due to endotoxin tolerance or a healthy worker effect in this population. This is the first study to evaluate the relationship between endotoxin's 3-OHFA constituents in agricultural dust and nasal airway inflammation. More research is needed to characterize the extent to which these agents contribute to respiratory disease among agricultural workers.

Fractionation of swine barn dust and assessment of its impact on the respiratory tract following repeated airway exposure

The effects of repeated exposure to a range of doses of swine barn dust (SBD) on airway hyperresponsiveness (AHR) and inflammation were evaluated using a mouse model system. A number of components, including endotoxin and a number of feed proteins, were identified in SBD, and mice were exposed 20 min/d for 14 d to a log dilution series of nebulized SBD suspensions. AHR to methacholine was measured using head-out whole-body plethysmography, and the methacholine concentration inducing a 20% decrease in pulmonary airflow (PC(20) MCh) was calculated. At the end of the 14-d exposure period, bronchoalveolar lavage (BAL) fluids were recovered, cytokines (interleukin [IL]-1beta, IL-6, keratinocyte-derived chemokine [KC], and tumor necrosis factor [TNF]) in BAL were measured by enzyme-linked immunosorbent assay (ELISA), and leukocytes in BAL were counted. The PC(20) MCh was significantly lower in the group of mice that were exposed to the highest concentration of SBD than in controls or the group exposed to the lowest level of dust. Likewise, the group that was exposed to the highest level of SBD had significantly higher levels of IL-1beta, KC, and TNF than controls and some other groups. There were substantially more lymphocytes and monocytes in the BAL from mice that were exposed to the higher levels of SBD for the 14-d period, but neutrophils were not a part of this response. The SBD exposures used in these experiments induced chronic inflammatory phenotype responses, as indicated by the predominance of lymphocytes and monocytes, but not neutrophils, in BAL and by inflammatory cytokines detected. The association between the PC(20)MCh and dose of SBD suggests that a threshold of susceptibility occurs after a relatively low, chronic exposure to SBD.

Relationship between sick building syndrome and indoor environmental factors in newly built Japanese dwellings

OBJECTIVES

Indoor air contaminants and dampness in dwellings have become important environmental health issues. The aim of this study is to clarify which factors are related to sick building syndrome (SBS) in newly built dwellings at Hokkaido, Japan, through a comprehensive evaluation of the indoor environment and validated sick building symptom questionnaires.

METHODS

The symptoms of 343 residents in 104 detached houses were surveyed by standardized questionnaires, and the concentrations of formaldehyde, acetaldehyde, volatile organic compounds (VOCs), airborne fungi, and dust mite allergen in their living rooms were measured. By summing the presence or absence of the five dampness indicators (condensations, mold growth, moldy odor, high air humidity of the bathroom, water leakage), a dampness index was calculated.

RESULTS

SBS symptoms were found in 21.6% of surveyed individuals. In a fully adjusted multivariate logistic regression analysis, the dampness index [odds ratio (OR) = 1.50; 95% confidence interval (CI): 1.06-1.11], log formaldehyde (OR = 23.79, 95% CI: 2.49-277.65), and log alpha-pinene (OR = 2.87, 95% CI: 1.36-6.03) had significantly higher ORs for SBS symptoms. However, other VOCs, airborne fungi, and dust mite allergen did not have significantly higher ORs.

CONCLUSION

Dampness, formaldehyde, and alpha-pinene were significantly related to SBS symptoms in newly built dwellings. We should, therefore, take measures to reduce the chemicals and dampness in dwellings.

Evaluation of oral corticosteroids and phosphodiesterase-4 inhibitor on the acute inflammation induced by inhaled lipopolysaccharide in human

BACKGROUND

Endotoxins are pro-inflammatory substances present in the environment. In man, inhalation of its purified derivative lipopolysaccharide (LPS) induces inflammation related to macrophages and neutrophils. Corticosteroids and phosphodiesterase (PDE)-4 inhibitors have inhibiting effects on macrophages and neutrophils, respectively. This study investigated the effect of prednisolone and of the PDE-4 inhibitor cilomilast on the LPS-induced acute inflammation.

METHODS

The study was a placebo-controlled, double-blind crossover design. On three occasions, at 2 weeks interval, 16 healthy subjects inhaled 50 microg LPS after a 6-day treatment with cilomilast (15 mg bd), prednisolone (10 mg bd) or placebo. For the assessment of the inflammatory response, induced sputum was obtained before inclusion and 6h post-LPS while blood samples were collected before, 6 and 24 h post-LPS.

RESULTS

Inhaled LPS induced an increase in sputum neutrophils (p<0.0001), logMMP-9 (p<0.05), logMMP-9/TIMP-1 (p<0.01) and logTNF-alpha (p<0.02). At the blood level there were significant rise in neutrophilia (p<0.001), E-selectin (p<0.02), C-reactive protein (CRP) (p<0.001) and LPS-binding protein (p<0.001). There was both a slight, but not significant, increase in body temperature and decrease in forced expiratory volume in 1 s (FEV(1)). Neither prednisolone nor cilomilast had protective effect on the LPS-induced airways' inflammation. The LPS-induced CRP acute-phase protein of inflammation (0.58+/-0.13 and 3.52+/-0.41 mg/dL, before and after LPS, respectively) was significantly inhibited by a pre-treatment with prednisolone (1.39+/-0.32 mg/dL, p<0.01) and attenuated (2.65+/-0.30 mg/dL, p=0.09) with cilomilast.

CONCLUSION

In healthy subjects, while the LPS-induced airways' inflammation was not modified either by oral prednisolone or by PDE-4 inhibitor cilomilast (at actual dosage), the LPS-induced acute phase of blood inflammation was reduced by prednisolone.

Comparison of the effects of erdosteine and N-acetylcysteine on apoptosis regulation in endotoxin-induced acute lung injury

This study was carried out to investigate comparatively the frequency of apoptosis in lung epithelial cells after intratracheal instillation of endotoxin [lipopolysaccharide (LPS)] in rats and the role of tumor necrosis factor alpha (TNF-alpha) on apoptosis, and the effects of erdosteine and N-acetylcysteine on the regulation of apoptosis. Female Wistar rats were given oral erdosteine (10-500 mg kg(-1)) or N-acetylcysteine (10-500 mg kg(-1)) once a day for 3 consecutive days. Then the rats were intratracheally instilled with LPS (5 mg kg(-1)) to induce acute lung injury. The rats were killed at 24 h after LPS administration. Lung tissue samples were stained with hematoxylin-eosin for histopathological assessments. The apoptosis level in the lung bronchial and bronchiolar epithelium was determined using the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick endlabelling) method. Cytoplasmic TNF-alpha was evaluated by immunohistochemistry. Pretreatment with erdosteine and pretreatment with N-acetylcysteine at a dose of 10 mg kg(-1) had no protective effect on LPS-induced lung injury. When the doses of drugs increased, the severity of the lung damage caused by LPS decreased. It was found that as the pretreatment dose of erdosteine was increased, the rate of apoptosis induced by LPS in lung epithelial cells decreased and this decrease was statistically significant in doses of 300 mg kg(-1) and 500 mg kg(-1). Pretreatment with N-acetylcysteine up to a dose of 500 mg kg(-1) did not show any significant effect on apoptosis regulation. It was noticed that both antioxidants had no significant effect on the local production level of TNF-alpha. These findings suggest that erdosteine could be a possible therapeutic agent for acute lethal lung injury and its mortality.

LPS inhalation challenge: a new tool to characterize the inflammatory response in humans

Inhaling bacterial endotoxin and its derivative LPS can induce a distinct inflammatory response, varying among hosts. Experimental LPS-inhalation is an established procedure in inflammation research. We evaluated experimental LPS-inhalation in 20 young healthy volunteers to determine the safety and the reproducibility of markers of inflammation and clinical findings (symptoms, lung function, exhalative NO, and body temperature). LPS was increased every 30 min up to cumulative 100 microg, the protocol was repeated after 2, 4, and 6 weeks. During 71 provocations, 13 episodes of clinical complaints were observed in 10 subjects. Those were a total of 11 local reactions (15.5%, e.g., cough), and six systemic reactions (8.5%, e.g., fatigue). All adverse events resolved spontaneously within 10 h. Changes of FEV(1) and eNO showed no significant differences between the four visits. In the majority of our subjects (88.2% on visit 1-3, 76.5% on visit 4), a rise in body temperature (>0.5 degrees C) was recorded and normalised latest after 24 h. On the first and the last visit, serum concentrations of CrP and LBP increased significantly and correlated well with each other (r=0.71; P<0.001). LPS-challenge is a safe and tolerable tool to investigate inflammatory response in humans and could lead to better characterization of patients with chronic inflammatory disease.

Safety of incremental inhaled lipopolysaccharide challenge in humans

BACKGROUND

Inhalation of environmental endotoxin is important in the pathogenesis of asthma and other environmental airway diseases. Inhaled airway challenge using lipopolysaccharide in humans has been performed for over 20 years to assess the airway response to endotoxin. However, there are no published data on the short-term safety of endotoxin inhalation protocols.

OBJECTIVE

To characterize the safety and tolerability of incremental inhaled lipopolysaccharide challenge in humans.

PATIENTS AND METHODS

We performed a retrospective analysis of data obtained from 119 subjects who underwent inhaled challenge with up to 41.5 mug of lipopolysaccharide. We measured pulmonary function, temperature, mean arterial pressure, heart rate, and systemic symptoms for 3 h after challenge.

RESULTS

Fever occurred in 30% of subjects and was associated with a higher cumulative dose of lipopolysaccharide. Reduced mean arterial pressure occurred in 21% of subjects and was dose-related. There was no association between fever or decreased mean arterial pressure and airway responsiveness to inhaled lipopolysaccharide. Common symptoms reported by subjects included: chills (64%), malaise (56%), cough (56%), chest tightness (49%), headache (43%), and myalgias (27%). None of the subjects experienced delayed discharge or a serious adverse event.

CONCLUSIONS

Inhaled lipopolysaccharide causes dose-related systemic responses that include fever, reduced blood pressure, and constitutional symptoms that are not associated with the airway response to inhaled lipopolysaccharide. Systemic responses to inhaled lipopolysaccharide should be expected and subjects undergoing inhaled lipopolysaccharide challenge in the research setting should be carefully monitored for non-pulmonary adverse events for several hours after challenge.

Inhaled endotoxin in healthy human subjects: A dose-related study on systemic effects and peripheral CD4+ and CD8+ T cells

BACKGROUND

Inhaled endotoxin or lipopolysaccharide (LPS) is implicated in the pathogenesis of pulmonary diseases. We investigated the inhalation effects of two different doses of LPS in healthy human subjects.

METHODS

Eighteen healthy non-atopic human subjects inhaled either 15 microg (n=10) or 50 microg (n=8)Escherichia coli LPS in an open study. As control, each subject had isotonic saline inhalation 1 week before (baseline) and after LPS inhalation. Data collected included those of clinical parameter, induced sputum and peripheral blood CD4+ and CD8+ T cells.

RESULTS

Acute flu-like symptoms and pyrexia were significantly greater in the 50 microg than 15 microg LPS group. Similarly, the increase in sputum and blood total cell and neutrophil counts at 6h following inhaled LPS were greater in the 50 microg group. Myeloperoxidase, human neutrophil elastase and interleukin-8 in sputum sol, but not blood, showed a trend towards greater increase following 50 microg LPS. All these changes were resolved at one week. In the 50 microg dose group alone, there was a reduction in the proportion of peripheral blood interferon (IFN)-gamma-producing CD4+ and CD8+ T cells at 6h followed by an increase at 1 week after inhaled LPS.

CONCLUSIONS

The airway and systemic effects of inhaled LPS are dose-related and predominantly neutrophilic. The changes in the proportions of circulating CD4+ and CD8+ T cells suggests preferential recruitment of IFN-gamma-producing T cells into tissue from inhaled 50 microg LPS, followed by reappearance of these cells in blood 1 week later.

Exposure to inhalable dust and endotoxins in agricultural industries

Endotoxin is a well-known bacterial toxin that causes several health effects. Animal faeces and plant materials contaminated with bacteria have been identified as important determinants of organic dust related endotoxin exposure. Although high exposure to organic dust and endotoxins has been described regularly in agricultural industries, a detailed overview of levels of airborne exposure to endotoxins in the agricultural industry, as well as a systematic comparison between several specific branches using the same exposure assessment protocols are lacking. In this study, personal endotoxin exposure in a broad spectrum of agricultural industries was investigated and possible determinants of exposure were explored. 601 personal inhalable dust samples were taken in 46 companies of three agricultural industrial sectors: grains, seeds and legumes sector (GSL), horticulture sector (HC) and animal production sector (AP), with 350 participating employees. Dust and endotoxin levels were determined gravimetrically and by using the Limulus Amoebocyte Lysate (LAL) assay, respectively. Basic descriptive analysis and elaborate analysis of variance were performed. Mean exposure levels were high, with large differences between sectors and between companies within the sectors. Highest dust and endotoxin exposures were found in companies of the GSL sector. In all three sectors exposure was higher in the primary production part compared to the (industrial) products processing part of the sector. The Dutch proposed health based occupational exposure limit (50 EU m(-3)) and temporary legal limit (200 EU m(-3)) for endotoxin were often exceeded. Differences in exposure between workers were larger than the day-to-day variability. Identified determinants increasing exposure levels were company, dustiness of the product and contact with animals/faeces. 'Wet' processes resulted in less dusty working environments and thus lowered endotoxin exposure. Overall, exposure to endotoxins over the whole range of agricultural industries is high. A 10-1,000 fold reduction in exposure is needed to reduce endotoxin related health risks.

Organic dust induced inflammation--role of atopy and TLR-4 and CD14 gene polymorphisms

BACKGROUND

Polymorphisms in the genes controlling for CD14 and TLR-4 may influence the outcome of endotoxin-induced effects.

MATERIALS AND METHODS

A study was performed on 146 workers in industries with exposure to organic dust containing endotoxin and 53 controls. Endotoxin exposure was measured at representative work sites. Inflammagenic markers, cytokines, and CD14 and TLR-4 polymorphisms were determined in blood.

RESULTS

Among workers, serum levels of esinophilic cationic protein (ECP) were lower compared to controls and the proportion of atopics was lower. Atopic persons had lower levels of IL-6 and IL-8, both among controls and exposed. IL-6 and ECP values were lower among those with TLR-4 /+896 AG and GG polymorphisms as compared to AA. Among atopic workers with CD-14(-550) polymorphism CC, IL-8 was lower.

COMMENTS

The results suggest that CD14 and TLR-4 polymorphisms influence regulators of the inflammation induced by endotoxin in organic dusts. Atopic persons have a lower secretion of certain inflammatory cytokines.

Relationship between exposure to domestic allergens and bronchial hyperresponsiveness in non-sensitised, atopic asthmatic subjects

BACKGROUND

The effect of exposure to allergens not causing sensitisation in atopic asthmatic subjects has not previously been studied. A study was undertaken to assess the degree of asthma severity (measured by spirometry, airway reactivity and exhaled nitric oxide) in atopic asthmatic patients not sensitised to the domestic allergen to which they were exposed.

METHODS

Dust samples were collected from the living room carpet and mattress in the homes of 248 subjects and dust mite, cat and dog allergen concentrations were measured. Spirometry, non-specific bronchial reactivity (BR), and exhaled nitric oxide (eNO) were ascertained. Patients' sensitisation status was assessed by skin prick testing.

RESULTS

Adult atopic asthmatics not sensitised to mite but exposed to high levels of mite allergen had significantly more severe BR than subjects not exposed to high levels of mite (PD(20), geometric mean (GM) 0.21 mg (95% CI 0.09 to 0.47) v 0.86 mg (95% CI 0.44 to 1.67), mean ratio difference 4.1 (95% CI 1.5 to 11.4), p=0.008). Subjects not sensitised but exposed to high levels of dog allergen also had significantly more severe BR than subjects not exposed (PD20 GM 0.16 v 0.52 mg, mean ratio difference 3.3 (95% CI 1.2 to 9.2), p=0.01). The differences in BR between these groups were still significant after adjusting for confounding factors. This effect of greater airway reactivity was not seen in subjects exposed but not sensitised to cat allergens.

CONCLUSION

Atopic asthmatic subjects who are exposed to high levels of dust mite or dog allergens but not sensitised to these allergens have evidence of increased airway reactivity.

Working Group report 1: tools for the diagnosis of organic dusts-induced disease

This paper describes the outcomes of the discussion of Working Group 1. The tasks of the workgroup were to: i) review current methods for the clinical diagnosis of organic dust induced disease, and ii) suggest how further research in this field should proceed. The working group proceeded on the paradigm that for diagnosis specific and precise tests are needed, where outcomes can be related to the risk for disease. The different methods available for the investigation of individuals and groups exposed to organic dusts are summed and graded according to scientific or diagnostic values. Many of the tools should be used in experimental research only, but can be used diagnostically for evaluation during follow up of patients when treated or removed from exposure. These techniques may also be employed for investigations of outbreaks, however, only after comparison with a proper control group. Future research should focus on associations between markers of inflammation and symptoms or clinical outcomes and dose-response relationships both for short-term and long-term health effects.

Exposure levels of asthmatic children to allergens, endotoxins, and serine proteases in a tropical environment

A cross-sectional study was conducted in Bayamón, Puerto Rico, to identify and quantify indoor allergens, serine proteases, and bacterial endotoxin present in homes of asthmatic children. A total of 126 dust samples from houses were obtained from the entire mattress and bedside floor. Most of the patients had detectable levels of mite, cockroach, cat, and dog allergens. Mold allergens were found only in bedside floor dust samples. Mouse allergens were not detected. Forty-two percent, 36.5%, and 1.8% of the patients demonstrated exposures to sensitizing levels of mite, Bla g 1 and cat allergens, respectively. The percentage of patients exposed to high levels of allergens capable of triggering asthma symptoms was 33.3% and 26.4% for mite and Bla g 1 allergens. Only dog allergen, bacterial endotoxin, elastase, and trypsin were associated with asthma symptoms. Eighty-nine percent of the asthmatic children were exposed to endotoxin concentrations greater than 100 EU/mg dust, and more than half of the patients were exposed to high levels of serine proteases. Our study indicates that indoor concentrations of allergens traditionally associated with asthma symptoms and severity may not be applicable in tropical environments and highly ventilated households. In fact, in the study population, endotoxins, dog allergen, and serine proteases may play a dominant role in the induction of asthma symptoms.

Work-related symptoms and inflammation among sewage plant operatives

Sewage operatives at five sewage treatment plants (n = 59) and controls not exposed to sewage (n = 55) were examined to determine work-related symptoms and inflammatory responses. Symptoms were elicited using a questionnaire, and spirometry was performed. Inflammatory markers were determined in blood and nasal lavage. Workplace endotoxin and hydrogen sulfide were measured and adeno- and enterovirus antibodies were evaluated in blood. Gastrointestinal and airway symptoms, joint pains, unusual tiredness, and toxic pneumonitis were more common among operatives, and the proportion of blood neutrophils was higher among operatives as compared with controls. A relationship was found between several reported symptoms and the inflammatory markers. Hydrogen sulfide levels were very low. Endotoxin levels were generally low, but high at some work sites.

Systemic responsiveness to lipopolysaccharide and polymorphisms in the toll-like receptor 4 gene in human beings

BACKGROUND

The response to lipopolysaccharide exposure is highly variable and might be a result of genetic diversity between individuals. The toll-like receptor 4 (TLR-4) is the principal receptor for lipopolysacharide.

OBJECTIVES

We investigated the association between single-nucleotide polymorphisms in the TLR4 locus and levels of systemic inflammatory markers in response to lipopolysaccharide.

METHODS

Healthy subjects (n = 116) were genotyped for the most frequent polymorphisms found in the promoter and coding region of the TLR4 gene (-2026A/T, -1607T/C, +896A/G, and +1196C/T relative to the translation start site). Subjects were challenged with 20 microg lipopolysaccharide by inhalation.

RESULTS

Polymorphisms at +896 and +1196 were in complete linkage disequilibrium, and no homozygotes for the less common allele, G and T respectively, were found. After lipopolysaccharide inhalation, subjects heterozygous for either TLR-4/+896 or TLR4/+1196 had significantly lower numbers of white blood cell counts and lower levels of C-reactive protein and lipopolysaccharide-binding protein compared with homozygotes with the common allele. None of the heterozygous subjects (n = 18) except 1 were high responders to lipopolysaccharide (defined as a rise in C-reactive protein > 10 mg/L), whereas 36 of 98 homozygous subjects were high responders (P <.02). No association was observed between the TLR-4/-2026 and TLR-4/-1607 polymorphisms and lipopolysaccharide responsiveness.

CONCLUSION

The single-nucleotide polymorphisms at position +896 or +1196 in the TLR-4 gene is associated with systemic inflammatory hyporesponsiveness to inhaled lipopolysaccharide.

Upper airway inflammation in waste handlers exposed to bioaerosols

AIMS

To examine work associated upper airway inflammation in 31 waste handlers, and to correlate these findings with personally monitored exposure to different bioaerosol components.

METHODS

Cell differentials, interleukin 8 (IL-8), myeloperoxidase (MPO), and eosinophilic cationic protein (ECP) were examined in NAL (nasal lavage), and swelling of the nasal mucosa was determined by acoustic rhinometry before work start on Monday and the following Thursday. Bioaerosol exposure was determined by personal full shift exposure measurements on Monday, Tuesday, and Wednesday and analysed for total bacteria, fungal spores, endotoxin, and beta(1-->3)-glucans.

RESULTS

The increased percentage of neutrophils from Monday (28%) to Thursday (46%) correlated with increases in ECP (r(S) = 0.71, p < 0.001) and MPO (r(S) = 0.38, p < 0.05), and showed a close to significant correlation with nasal swelling (r(S) = -0.55, p = 0.07). The Thursday levels of neutrophils, MPO, and IL-8 were associated with the exposure to fungal spores (range 0-2.0 x 10(6)/m(3)) and endotoxin (range 4-183 EU/m(3)) measured the day before, and the median exposure to beta(1-->3)-glucans (range 3-217 ng/m(3)), respectively (r(S) = 0.47-0.54, p < 0.01). Swelling of the nasal mucosa was associated with the fungal spore and beta(1-->3)-glucan exposure (r(S) = 0.58-0.59, p < 0.05).

CONCLUSION

These results are based on a relatively small population, and conclusions must be drawn with care. The results suggested that a moderate exposure to fungal spores, endotoxins, and beta(1-->3)-glucans during waste handling induced upper airway inflammation dominated by neutrophil infiltration and swelling of the nasal mucosa.

Effects of various applications of lipopolysaccharides on blood parameters of pigs

In five experiments, lipopolysaccharides (LPS) of Escherichia coli O26:B6 and O111:B4 were applied intravenously, intramuscularly, subcutaneously or intrabronchially in doses of 5000-15,000 U/kg body mass to a total of 47 weaner pigs and compared with the application of sodium chloride. Different parameters of blood cells were investigated, including cell numbers, in vivo interleukin secretion, radical formation, phagocytosis capacity and IL-6 as well as TNFalpha formation ex vivo. Non-specific effects and dependencies on the type of application and LPS dose are discussed.

Work related symptoms among sewage workers: a nationwide survey in Sweden

AIMS

To assess the risk for work related symptoms among sewage workers in Sweden using a postal questionnaire.

METHODS

All municipalities in Sweden were contacted and asked to provide addresses of sewage workers and controls. Controls were recruited among other municipal workers not exposed to sewage, such as workers in drinking water plants and gardeners. A questionnaire was sent to the subjects and after two reminders, the response rate was 74% among sewage workers and 59% among controls.

RESULTS

Significantly increased risks for airway symptoms, chronic bronchitis, and toxic pneumonitis, as well as central nervous system symptoms such as headache, unusual tiredness, and concentration difficulties were found among the sewage workers compared with controls. Furthermore, an increased risk for non-specific work related gastrointestinal symptoms was found among the sewage workers; an increased risk for joint pains, related to pains in more than four joints but not with loading, was also found.

CONCLUSIONS

The results of this questionnaire survey show an increased risk for airway, gastrointestinal, and general symptoms such as joint pains and central nervous system symptoms among sewage workers. Clinical investigations are needed to determine the cause of the reported symptoms among sewage workers, and further field studies are required to assess the causal agents.

Effects after inhalation of (1-->3)-beta-D-glucan and relation to mould exposure in the home

BACKGROUND

Damp conditions indoors favour the growth of microorganisms, and these contain several agents that may cause inflammation when inhaled. Moulds contain a polyglucose in their cell wall, defined as (1-->3)-beta-D-glucan, exhibiting effects on inflammatory cells.

AIM

The aim of the present study was to evaluate whether an inhalation challenge to purified (1-->3)-beta-D-glucan (grifolan) in humans could induce effects on inflammatory markers in blood, and to evaluate whether the reactions were related to the home exposure to (1-->3)-beta-D-glucan.

METHODS

Seventeen subjects in homes with high levels of airborne (1-->3)-beta-D-glucan (G-high) and 18 subjects in homes with low levels of (1-->3)-beta-D-glucan (G-low) underwent two randomised, double-blind inhalation challenges, one to (1-->3)-beta-D-glucan suspended in saline and one to saline alone. A blood sample was taken before and after the challenges, and differential cell count, granulocyte enzymes in serum and the secretion of cytokines from peripheral blood mononuclear cells (PBMC) were measured.

RESULTS

Inhalation challenge with (1-->3)-beta-D-glucan induced a decrease in the secretion of tumour necrosis factor alpha from endotoxin-stimulated PBMC in the G-high group as well as in the G-low group. In the G-high group, the inhalation of (1-->3)-beta-D-glucan induced an increase in blood lymphocytes that was significantly different from the saline-induced effect.

CONCLUSIONS

The results suggest that an inhalation challenge to (1-->3)-beta-D-glucan has an effect on inflammatory cells and this effect may be related to a chronic exposure to moulds at home.

Does environmental endotoxin exposure prevent asthma?

The evidence as to whether exposure to environmental airborne endotoxin plays a protective or an inducing role in the development of asthma is reviewed. Studies of endotoxin and atopy, endotoxin and asthma, and farming and asthma are considered and, in each instance, a distinction is made between evidence of primary causation and evidence of secondary causation. It is concluded that, although it is plausible that bacterial endotoxin may protect against the development of asthma, there is considerable reason for caution regarding this hypothesis.

Health effects among employees in sewage treatment plants: A literature survey

BACKGROUND

Over the years, there have been regular reports in the media of work-related symptoms among employees at sewage treatment plants. Concern has spread among employees over the lack of knowledge of risk agents' symptoms, and diseases in that environment. This paper reviews the investigations of health risks in employees working in the sewage treatment plants.

METHODS

A literature search was performed with the search terms; sewage, waste water, health effects, infection, and health hazards. Articles on health effects in relation to sewage were selected.

RESULTS

Work in sewage water plants can involve exposure to different types of microorganisms and chemicals. The bacterial exposure is dominated by bacteria that naturally occur in nature. However, different bacteria and viruses that give rise to infections can be present in this environment and thus there exists a risk of infection, especially of hepatitis A. Investigations suggest that gastrointestinal tract symptoms are more common among employees at sewage treatment plants than among controls. Respiratory symptoms, fatigue, and headache have also been reported in several investigations. The cause of the symptoms is unknown, although certain data suggest that they are caused by inflammation. The results suggest that endotoxin in Gram-negative bacteria may be one of the causative agents. As regards cancer, some studies report an increased risk of stomach cancer and a few studies report an increased risk of cancer in the larynx, liver or, prostate or of leukemia. The spread of the cancers over a multitude of organs does not support a hypothesis of causality with agents commonly found in sewage treatment plants.

CONCLUSIONS

Further investigations are needed to determine the work-related effects and ascertain the causal agents.

Effects after inhalation of (1-->3)-beta-D-glucan in healthy humans

BACKGROUND AND AIM

This study was performed to assess the effects of an exposure to a pure (1-->3)-beta-D-glucan, a cell wall component of fungi, plants and certain bacteria.

METHODS

Twenty-one healthy subjects inhaled saline or (1-->3)-beta-D-glucan suspended in saline in a random, double-blind, cross-over design. They were examined before exposure and 24 and 72h afterwards with spirometry, blood sampling and collection of induced sputum. Differential cell counts and eosinophilic cationic protein (ECP) were determined in blood and sputum, and myeloperoxidase (MPO), tumour necrosis factor-alpha (TNF-alpha), and interleukin (IL)-8 and IL-10 were determined in sputum supernatants. TNF-alpha was determined after cultivation of blood mononuclear cells.

RESULTS

In sputum, inhalation of saline caused a significant increase in ECP and TNF-alpha. (1-->3)-beta-D-Glucan inhalation caused a further increase in these cytokines, although not statistically significantly different from the increase induced by inhalation of saline alone. In blood, the number of eosinophils was significantly decreased 72 h after the challenge with (1-->3)-beta-D-glucan. This effect was not found after the inhalation of saline alone. TNF-alpha production from stimulated blood mononuclear cells was significantly decreased 72 h after the (1-->3)-beta-D-glucan inhalation as compared with the increase induced by saline inhalation.

CONCLUSIONS

The results suggest that (1-->3)-beta-D-glucan causes a different type of response as compared with inflammatory agents such as bacterial endotoxin that cause a neutrophil-dominated inflammatory response.

Healthy subjects express differences in clinical responses to inhaled lipopolysaccharide that are related with inflammation and with atopy

BACKGROUND

Endotoxin and its purified derivative LPS are important contaminants of both domestic and occupational environments that have been related to airway diseases. A body of data suggests that there is considerable interindividual variability in LPS sensitivity.

OBJECTIVE

The aim of the study was to relate the individual clinical responses to inhaled LPS with the inflammatory process and the atopic status.

METHODS

Fifteen healthy subjects were challenged each week by inhalation with saline solution or LPS (0.5, 5, or 50 microg). The systemic response was defined by the increase in body temperature, blood neutrophilia, acute-phase proteins (C-reactive protein and LPS-binding protein [LBP]), and E-selectin. The LPS-induced airway response was defined as the increase in airway responsiveness and related to the cell count and concentration of TNF-alpha, myeloperoxidase, and eosinophil cationic protein in induced sputum. The atopic status was defined as an increase in IgE or a positive skin prick test result.

RESULTS

Subjects (n = 7) with a significant increase in body temperature had a larger increase in the systemic inflammatory response (blood neutrophilia; P <.01) and in blood concentrations of C-reactive protein (P <.02) and LBP (P <.01). Subjects with a significant increase in airway responsiveness (n = 8) had an increase in the sputum concentration of eosinophil cationic protein (P <.01). The amplitude of the systemic response (increase in body temperature [P <.001], blood neutrophilia [P <.02], and rise in LBP [P <.05] and decrease in FEV(1) [P <.01]) were inversely associated with the atopic status, suggesting a link between atopy and LPS responsiveness.

CONCLUSIONS

The clinical response to LPS occurs systemically or locally and is associated with inflammation. The atopic status was inversely related to the systemic inflammation.