Bacterial Endotoxin Is an Active Component of Cigarette Smoke

Exposure to airborne endotoxin in infancy may protect against asthma by promoting enhanced TH1 response and tolerance to allergens. On the other hand, later in life, it adversely affects patients with asthma. Endotoxin binding to receptors on macrophages and other cells generates IL-12, which inhibits IgE responses. It also generates cytokines like IL-1, TNF-α, and IL-8, which cause inflammation. These signal transduction pathways resemble those leading to the generation of cytokines, such as IL-4, IL-13, and IL-5, which are responsible for the inflammation of IgE-mediated allergic disease. The main difference seems to be that endotoxin recruits neutrophils, but IgE recruits eosinophils, and the details of the tissue injury from these granulocytes differ. Sources of airborne endotoxin include many agricultural dusts, aerosols from con-taminated water in many industrial plants, contaminated heating and air-conditioning systems, mist-generating humidifiers, and damp or water-damaged homes. Acute inhalation of high concentrations of endotoxin can cause fever, cough, and dyspnea. Chronic inhalation of lesser amounts causes chronic bronchitis and emphysema and is associated with airway hyperresponsiveness. Airborne endotoxin adversely affects patients with asthma in 3 ways: (1) by increasing the severity of the airway inflammation; (2) by increasing the susceptibility to rhinovirus-induced colds; and (3) by causing chronic bronchitis and emphysema with development of irreversible airway obstruction after chronic exposure of adults. The most effective management is mitigating exposure. The potential of drug treatments requires further clinical investigation. (J Allergy Clin Immunol 2001;108:157-66.)

https://www.jacionline.org/article/S0091-6749(01)32579-4/pdf

Endotoxin-stimulated innate immunity: A contributing factor for asthma.

OBJECTIVES: The aims of this study were to document the prevalence of work related upper and lower respiratory tract symptoms in workers exposed to organic dusts and to identify variables predictive of their occurrence. METHODS: A cross sectional survey with an administered questionnaire (a previously validated adaptation of the Medical Research Council (MRC) respiratory questionnaire) was performed. Symptoms were classified as work related by their periodicity. Demographic data, smoking habits, and occupational histories were recorded. Personal exposures to dust and endotoxin were measured and individual subjects ascribed an exposure value specific to occupation, site and industry. Cox's regression techniques were used to identify variables predictive of work related upper and lower respiratory tract symptoms. Information was stored using Dbase 3 and analysed with SPSS. RESULTS: 1032 Workers (93% of the target population) were studied in nine different industries. The highest prevalences of work related lower respiratory tract symptoms (38.1%), upper respiratory tract symptoms (45.2%), and chronic bronchitis (15.5%) were found among poultry handlers. White workers were significantly more likely to complain of upper and lower respiratory tract symptoms. An individual in the swine confinement industry had a symptom complex compatible with byssinosis. Increasing current personal exposures to dust or endotoxin were found to be predictive of upper and lower respiratory tract symptoms, chronic bronchitis, and byssinosis. In a univariate analysis a relation between current exposures and the organic dust toxic syndrome was found. Present smoking and previously documented respiratory tract illness were significantly predictive of work related lower respiratory tract symptoms. Women were more likely to report work related upper respiratory tract symptoms. CONCLUSIONS: People exposed to organic dusts may have a high prevalence of work related respiratory tract symptoms which are related to dust exposures and smoking habits. Action should be taken to reduce exposures to dust and endotoxin and stopping smoking should be promoted among workers exposed to organic dusts to reduce morbidity.

https://oem.bmj.com/content/oemed/55/10/668.full.pdf

Prevalence and predictors of work related respiratory symptoms in workers exposed to organic dusts.

Purpose of reviewThis review provides an update on the role of bacterial endotoxin in occupational airway disease, a problem of importance from diagnostic and preventive points of view.Recent findingsData from human inhalation studies have increased our understanding of the cell mechanisms underlyin

Endotoxin and occupational airway disease.

This study tested the importance of filter media, extraction and assay protocol, and bioaerosol source on the determination of endotoxin under field conditions in swine and poultry confinement buildings. Multiple simultaneous air samples were collected using glass fiber (GF) and polycarbonate (PC) filters, and these were assayed using two methods in two separate laboratories: an endpoint chromogenic Limulus amebocyte lysate (LAL) assay (QCL) performed in water and a kinetic chromogenic LAL assay (KQCL) performed in buffer with resistant-parallel line estimation analysis (KLARE). In addition, two aqueous filter extraction methods were compared in the QCL assay: 120 min extraction at 22°C with vigorous shaking and 30 min extraction at 68°C with gentle rocking. These extraction methods yielded endotoxin activities that were not significantly different and were very highly correlated. Reproducibility of endotoxin determinations from duplicate air sampling filters was very high (Cronbach α all > 0.94). When an...

Field Evaluation of Endotoxin Air Sampling Assay Methods

All the 303 full time day workers in a carpet weaving factory were submitted to a physical examination, chest radiography, and vitalograph test, and answered a respiratory questionnaire. Fifty four healthy non-exposed subjects served as controls. Dust concentrations and concentrations of bacterial endotoxin were measured. Of the 303 workers, 259 (85.5%) had airway symptoms and 62 (20.5%) had maximum mid-expiratory flow (MMF) values of less than 60% compared with 9.2% of the controls. The symptoms in 68 workers (22%) were compatible with byssinosis and 36 of these workers underwent vitalography before starting work and after four hours work on Mondays when significant reductions of their FEV1 and MMF were found. Twenty one of these 36 workers were tested on Tuesday and no differences in these measurements were found between measurements before work started and four hours later. The airborne dust concentrations in the factory were high and bacterial endotoxin was found. These findings suggest that a large number of workers in this carpet weaving factory suffer from a disease indistinguishable from byssinosis even though wool is used almost exclusively, the only cotton being the warp. The finding of endotoxin together with the absence of cotton confirms the theory that "byssinosis" is due to bacterial endotoxin rather than to cotton per se.

https://oem.bmj.com/content/oemed/44/7/479.full.pdf

Y I Baris

Papers

Byssinosis in carpet weavers exposed to wool contaminated with endotoxin.