Symptoms and mechanisms--inflammation of the lung

The various phases of the lung inflammatory response to inhaled agents are reviewed and linked to the clinical symptoms and syndromes. Available data suggest that inflammation is the major reason for the symptoms appearing after organic dust exposure.

Bird droppings contain endotoxin and (1-->3)-beta-D-glucan

Samples of bird droppings were collected and the amount of endotoxin and (1-->3)-beta-D-glucan in these was determined using a specific Limulus assay. All samples contained these agents and calculations on airborne levels demonstrated that doses at risk for inflammation and allergic alveolitis were present. Endotoxin and (1-->3)-beta-D-glucan should be considered in investigations on lung disease induced by bird droppings.

Lipopolysaccharide (LPS) inhalation in healthy subjects causes bronchoalveolar neutrophilia, lymphocytosis, and fibronectin increase

Eight healthy volunteers were exposed to purified lipopolysaccharide (LPS) by controlled inhalation. Bronchoalveolar lavage (BAL) 3 hours after exposure revealed a pronounced neutrophilia, increase in lymphocytes, fibronectin concentration, and decrease in alveolar macrophage phagocytosis, as compared to a reference BAL.

Bronchial reactivity, atopy, and airway response to cotton dust

Studies of cotton textile workers have found an association between atopy and drop in FEV1 over a workshift. We studied the response of previously nonexposed volunteers with and without a history of mild atopy to a 5-h exposure to 1 mg/m3 of respirable cotton dust in a model cardroom. All participants were nonsmokers, had no history of asthma, and had normal spirometry. Twenty atopic subjects gave a personal history of mild respiratory allergy to pollen, dusts, or animals that had been confirmed by a physician. Thirty-two nonatopic subjects had no history of allergy. Spirometry and a methacholine challenge test were performed 1 to 2 days prior to exposure. Spirometry was repeated immediately before exposure to cotton dust; spirometry and a methacholine challenge were performed immediately after exposure. Atopic subjects showed a significantly higher mean serum IgE level to Phadiatop, a screening test to common inhalant allergens, than did nonatopic subjects (mean percent binding, 32.1 versus 1.5; p < 0.001). Atopic subjects had a significantly greater mean fall in FEV1 during exposure (8.3% versus 4.9%, p < 0.05). The difference in FEV1 decline between atopic and nonatopic subjects was similar in magnitude to that reported for workshift FEV1 declines between textile workers with and without mild atopy. Atopic subjects had significantly higher baseline methacholine responsiveness than did nonatopic subjects (26% versus 0% reaching a PD20, p < 0.0005). After cotton dust exposure, there was a significant increase in airway reactivity in both groups (68% versus 20% reaching a PD20, p < 0.0005). For all subjects combined baseline responsiveness was significantly related to the change in FEV1 after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Lung inflammatory cells after exposure to mouldy hay

To investigate the inflammatory cell response after exposure to mouldy hay, guinea pigs were exposed to an aerosol of spores from mouldy hay. Lung wall (LW) and lung lavage (LL) cells were counted after 5 weeks of daily exposures. At 5 weeks both LW and LL macrophages, lymphocytes and neutrophils increased. The LL cell increase was proportionally higher. At 12 weeks, the increase in the number of cells was slightly less than at 5 weeks. After cessation of exposure, macrophages and lymphocytes remained elevated up to 7 days whereas neutrophils rapidly decreased to normal values. This animal inhalation model of early allergic alveolitis could be used to evaluate the importance of different exposure conditions and various agents in the dust.

Genetic polymorphism of cytochrome P4502E1 in a Swedish population. Relationship to incidence of lung cancer

Genetic polymorphism of CYP2E1 was investigated among 195 Swedish patients with lung cancer and 206 controls. Three different polymorphic sites were found, all in introns, using RFLP and the restriction enzymes DraI, RsaI and TaqI. The frequencies of the rare alleles were 0.08-0.18 and much lower than previously described among Japanese. No significant difference in distribution of the polymorphic alleles between controls and lung cancer patients was evident, in contrast to results of a previous Japanese study. However, examination of a polymorphic site in the 5'-flanking region, within a putative binding motif for the hepatic transcription factor HNF-1, revealed a significantly less frequent distribution of the mutated allele (c2) among the lung cancer patients as compared to controls. It is concluded that major interethnic differences exist in the genetic polymorphism of CYP2E1 and that people carrying the c2 allele might be at lower risk for developing lung cancer.

Bronchial reactivity among cotton workers in relation to dust and endotoxin exposure

Bronchial reactivity was measured before work among non-smoking female and male workers from carding, spinning, warping and weaving areas in a cotton mill. Airport baggage loaders were used as controls. The amount of dust and endotoxin was measured at the different workplaces. Statistically significant decreases in FEV1 were found between groups of cotton workers at different work sites after administration of the highest accumulated methacholine dose used (1.25 mg). A relationship was found between decreases in FEV1 after methacholine challenge and airborne endotoxin levels but not for dust.

Effects of oral and intravenous administration of endotoxin in prepubertal gilts

The effect of oral intake of endotoxins was studied in 12 prepubertal gilts. The animals were given 30 or 100 mg of ET each in their regular morning feed ration. Blood samples were collected periodically during 24 h and the clinical status, including rectal temperature, was recorded at the same time. Hematological and clinical chemical analyses that included serum bile acids, glutamate dehydrogenase, alkaline phosphatase, calcium, iron, zinc and a blood plasma metabolite of prostaglandin F2 alpha, were done. The animals showed no obvious clinical symptoms following endotoxin feeding. The major findings were increased bile acid and glutamate dehydrogenase values with the most prominent rises being recorded 10-12 h after endotoxin intake. In a later experiment, 6 animals were injected i.v. with endotoxin in doses in the range 0.1-0.5 micrograms/kg b.w. Blood samples were taken and analysed as in the endotoxin-feeding experiment. Within 1 h of injection, all animals showed symptoms such as vomiting, fever and dyspnea. The clinical signs disappeared within 2-5 h. The injections were followed by increases in bile acids, glutamate dehydrogenase and prostaglandin F2 alpha metabolite. To conclude, this study indicates that clinically healthy prepubertal gilts react to ingested endotoxin in feed but that no apparent clinical disturbances ensue.

Effects of noise on mental performance with regard to subjective noise sensitivity

Objective and subjective effects of moderate levels of recorded traffic noise [Leq = 55 dB(A) and 75 dB(A)] on mental performance were studied in a laboratory setting. A total of 45 subjects (23 males and 22 females) were investigated with respect to subjective noise sensitivity (SNS). Four cognitive tasks were applied involving different psychological functions: Short-Term Memory (STM), Search and Memory 5 (SAM 5) (vigilance), Hidden Figures (HF) (spatial reasoning) and Mental Arithmetic (MA) (parallel processing). Three groups of 15 subjects were defined according to their scores on Weinstein's Noise Sensitivity Scale as tolerant, moderately sensitive or highly sensitive to noise. A similar level of performance was observed in the three groups under quiet conditions [30 dB(A) Leq], but under noisy conditions significant differences (P < 0.05) were seen between them on the STM (words) and MA (total results) tasks, and the lowest performance accuracy was demonstrated by the noise-sensitive subjects. SNS was the primary factor responsible for these differences. There were no significant differences between the groups in respect of the SAM 5 and HF tasks, under either quiet or noisy conditions. Annoyance while performing tasks under noisy conditions was regularly and significantly higher among subjects judged to be noise sensitive on Weinstein's scale, as compared with those judged to have low or moderate SNS.

Reduction of alveolar-capillary diffusion after inhalation of endotoxin in normal subjects

Normal subjects were exposed to an aerosol of Escherichia coli endotoxin. Carbon monoxide diffusion (Dco), spirometry, blood neutrophils, white blood cells, and platelets were determined at various times thereafter. A significant decrease in Dco and an increase in blood neutrophils was found, with a maximum effect 4 to 8 h after exposure. Exposure to distilled water caused a tendency for Dco to decrease and a significant increase in blood neutrophils. No effect on spirometry or body temperature was detected. It is suggested that the changes observed represent an inflammation at the alveolar level that appears at dose levels of endotoxin below those which cause bronchoconstriction and fever.

Lipopolysaccharide (LPS) inhalation in healthy subjects increases neutrophils, lymphocytes and fibronectin levels in bronchoalveolar lavage fluid

Bacterial endotoxin has been suggested as responsible for the development of subjective symptoms and transient or chronic lung function impairment seen after exposure to organic dusts in cotton mills, poultry houses, swine confinement buildings and saw mills. Animal experiments have demonstrated bronchoalveolar neutrophilia being the most prominent cell response in animals following bacterial lipopolysaccharide (LPS) inhalation. The present study was conducted to obtain information on some aspects of the early inflammatory response to inhaled LPS in man. Eight healthy nonsmoking subjects, 23-27 yrs old, underwent bronchoalveolar lavage (BAL), 3 h after a provocation test with 100 micrograms LPS from E. coli dissolved in 2 ml isotonic NaCl. The solution was aerosolized with a jet nebulizer and inhaled. The calculated dose delivered to the lung was approximately 25 micrograms, which equals exposure in some occupational settings. The BAL data for each individual subject were compared with data from a control BAL performed at least 6 weeks prior to the LPS challenge. The major cellular response to LPS, reflected in BAL fluid, was an approximately hundredfold increase in neutrophils. The total number of lymphocytes was on average tripled. The alveolar macrophage phagocytosis of opsonized yeast particles in vitro was significantly reduced. A further indicator of an ongoing inflammation was an increase in fibronectin. No changes were seen in the levels of BAL albumin, indicating that the elevated level of fibronectin could not be explained by an increased permeability, but rather by a local production. The results correspond with data from animal studies and further supports the hypothesis that bacterial LPS is important in the pulmonary reaction induced by organic dusts.

Aircraft noise annoyance and average versus maximum noise levels

A questionnaire study was performed in seven areas located around the airports of Landvetter and Save, Gothenburg, in an attempt to elucidate the extent of annoyance in populations exposed to aircraft noise. Noise exposure was estimated as the energy equivalent level (Aircraft Noise Level--FBN) or as the number of aircraft with levels that exceeded 70 dBA, combined with the maximum noise level. The results were compared with data obtained from the earlier Scandinavian Aircraft Noise Investigation. The results supported the conclusion that the annoyance reaction is better related to the number of aircraft and the maximum noise level than to energy equivalent levels for noise exposure.

Lipopolysaccharide (LPS) inhalation in healthy subjects increases neutrophils, lymphocytes and fibronectin levels in bronchoalveolar lavage fluid

Bacterial endotoxin has been suggested as responsible for the development of subjective symptoms and transient or chronic lung function impairment seen after exposure to organic dusts in cotton mills, poultry houses, swine confinement buildings and saw mills. Animal experiments have demonstrated bronchoalveolar neutrophilia being the most prominent cell response in animals following bacterial lipopolysaccharide (LPS) inhalation. The present study was conducted to obtain information on some aspects of the early inflammatory response to inhaled LPS in man. Eight healthy nonsmoking subjects, 23-27 yrs old, underwent bronchoalveolar lavage (BAL), 3 h after a provocation test with 100 micrograms LPS from E. coli dissolved in 2 ml isotonic NaCl. The solution was aerosolized with a jet nebulizer and inhaled. The calculated dose delivered to the lung was approximately 25 micrograms, which equals exposure in some occupational settings. The BAL data for each individual subject were compared with data from a control BAL performed at least 6 weeks prior to the LPS challenge. The major cellular response to LPS, reflected in BAL fluid, was an approximately hundredfold increase in neutrophils. The total number of lymphocytes was on average tripled. The alveolar macrophage phagocytosis of opsonized yeast particles in vitro was significantly reduced. A further indicator of an ongoing inflammation was an increase in fibronectin. No changes were seen in the levels of BAL albumin, indicating that the elevated level of fibronectin could not be explained by an increased permeability, but rather by a local production. The results correspond with data from animal studies and further supports the hypothesis that bacterial LPS is important in the pulmonary reaction induced by organic dusts.

Diseases associated with exposure to plant dusts: focus on cotton dust

Research during recent years has made clear that pulmonary disease and certain general symptoms caused by organic dusts are far more common than previously suspected. To the traditional environments of cotton dust and moldy hay has been added a series of environments, such as swine confinement buildings, sewage treatment stations and industrial fermentation plants. It has been suggested that, rather than linking clinical disease with a specific environment (farmer's lung, byssinosis, etc), symptoms should be related to the relevant pulmonary cellular reactions, particularly inflammation. In so doing, a more homogenous picture of the various clinical entities has emerged. It is now understood that symptoms once considered to be unique to one particular environment, such as chest tightness in cotton mills, are also present in other organic dust environments. New models for organic dust-induced disease have been established using the criteria developed for disease among workers in cotton mills and swine confinements buildings. This has led to uniform methods for diagnosis, description of symptomatology and understanding of pathogenesis. Employing this experience on an international basis, provides an important background for dealing with new problems in this important area of occupational health and is a prerequisite for the establishment of treatment and prevention programs.

Acute pulmonary toxicity of inhaled beta-1,3-glucan and endotoxin

The number of inflammatory cells was studied in lung walls and airways after inhalation of endotoxin or beta-1,3-glucan. In the water unsoluble form, beta-1,3-glucan caused a delayed response in terms of a decrease in macrophages and lymphocytes in the lung wall, 1 to 7 days after exposure but no invasion of neutrophils into the airways. When solubilized in 0.02 N NaOH, the cell response was the same as that observed after exposure to endotoxin.

Tumor necrosis factor and interleukin-1 activities in free lung cells after single and repeated inhalation of bacterial endotoxin

Bacterial endotoxins (lipopolysaccharides), important components of many organic dusts, are known to induce macrophages to produce the inflammatory mediators interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha). To investigate the role of these mediators in the early inflammatory responses in the lung, guinea pigs were exposed to an aerosol of bacterial endotoxin. A bronchoalveolar lavage (BAL) was then performed, and TNF-alpha and IL-1 in lysed BAL cells and in the supernatants from BAL cell cultures were studied. The effect of single and repeated LPS inhalation exposures on the activities of TNF and IL-1 was studied, as was the effect of LPS added to the cell culture medium. A single inhalation exposure to LPS caused an increase in the TNF-alpha and IL-1 activities in cell lysate and in the cell culture supernatant. After a second inhalation exposure, cell-associated and extracellular TNF-alpha activity could not be detected, whereas IL-1 activity was markedly enhanced. IL-1 activity was increased when LPS was added to the cell culture medium with or without a prior inhalation exposure. In contrast, TNF-alpha activity was not affected after a second exposure.

Experimental allergic alveolitis after exposure to different microorganisms

The experiments described here examined the capacity of different microorganisms to induce allergic alveolitis. Guinea-pigs were exposed to an aerosol of pure cultures of five different organisms, four of which are common in mouldy hay, without previous injection of an adjuvant. The animals were either acutely exposed or exposed for 3 to 5 weeks, after which the numbers of different inflammatory cells in the airways were counted and histological changes in the lung parenchyma were assessed. It was seen that prolonged exposures to large numbers of spores produced a cellular infiltration in the alveolar and bronchiolar region, and gave rise to lesions resembling early granulomas. The number of lymphocytes increased in the airways. The results suggest that allergic alveolitis can be induced by inhalation of various kinds of microorganisms and that these may vary in their capacity to produce the disease.