Cotinine excretion (tobacco smoke biomarker) of smokers and non-smokers: comparison of GC/MS and RIA results

Development in competitive immunoassay of a point-of-care testing for cotinine (COT) detection in urine

We present a sensitive and selective lateral flow immunoassay (LFIA) for cotinine (COT), the primary metabolite of nicotine. COT is widely recognized as a superior biomarker to evaluate tobacco smoke exposure. The LFIA uses a competitive assay format where the COT-BSA capture competes with the target COT in urine samples for binding to the monoclonal antibody against COT (mAb-COT) conjugated with gold nanoparticles (mAb-COT-AuNPs). To improve the sensitivity and selectivity of the LFIA-COT, we focused on optimizing the diameter of AuNPs, the conjugation of mAb-COT, and the concentration of the COT-BSA capture. Our findings reveal that the utilization of 40 nm AuNPs in conjugation with a concentration of 4 mg mL-1 of mAb-COT demonstrated significantly greater efficacy compared to LFAs utilizing 20 nm AuNPs. Under the optimal conditions, the LFIA-COT demonstrated sensitive detection of COT at a level of 150 ng mL-1 within 15 min, as observed by the naked eye. It possesses a linear range of 25 to 200 ng mL-1 of COT, with the limit of detection (LOD) of 11.94 ng mL-1 in human urine samples when the color intensity is analyzed using ImageJ software. Our LFIA described here is simple and requires less time for COT detection. It can be used for the rapid and quantitative detection of COT in urine samples in clinical settings.

Characterization of cotinine degradation in a newly isolated Gram-negative strain Pseudomonas sp. JH-2

Cotinine, the primary metabolite of nicotine in the human body, is an emerging pollutant in aquatic environments. It causes environmental problems and is harmful to the health of humans and other mammals; however, the mechanisms of its biodegradation have been elucidated incompletely. In this study, a novel Gram-negative strain that could degrade and utilize cotinine as a sole carbon source was isolated from municipal wastewater samples, and its cotinine degradation characteristics and kinetics were determined. Pseudomonas sp. JH-2 was able to degrade 100 mg/L (0.56 mM) of cotinine with high efficiency within 5 days at 30 ℃, pH 7.0, and 1% NaCl. Two intermediates, 6-hydroxycotinine and 6-hydroxy-3-succinoylpyridine (HSP), were identified by high-performance liquid chromatography and liquid chromatograph mass spectrometer. The draft whole genome sequence of strain JH-2 was obtained and analyzed to determine genomic structure and function. No homologs of proteins predicted in Nocardioides sp. JQ2195 and reported in nicotine degradation Pyrrolidine pathway were found in strain JH-2, suggesting new enzymes that responsible for cotinine catabolism. These findings provide meaningful insights into the biodegradation of cotinine by Gram-negative bacteria.

Influence of Selective Extraction/Isolation of Heme/Hemoglobin with Hydrophobic Imidazolium Ionic Liquids on the Precision and Accuracy of Cotinine ELISA Test

In this study, ionic liquids were used for the selective extraction/isolation of hemoglobin from human serum for cotinine determination using the ELISA Kit. The suitability of hydrophobic imidazolium-based ionic liquids was tested, of which OMIM BF₄ (1-methyl-3-octylimidazolium tetrafluoroborate) turned out to be the most suitable for direct extraction of hemoglobin into an ionic liquid without the use of any additional reagent at one extraction step. Hemoglobin was separated quantitatively (95% recovery) from the remaining types of proteins remaining in the aqueous phase. Quantum mechanical calculations showed that the interaction of the iron atom in the heme group and the nitrogen atom of the ionic liquid cation is responsible for the transfer of hemoglobin whereas molecular dynamics simulations demonstrated that the non-covalent interactions between heme and solvent are more favorable in the case of OMIM BF₄ in comparison to water. The opposite trend was found for cotinine. Selective isolation of the heme/hemoglobin improved the ELISA test's accuracy, depending on the cotinine level, from 15% to 30%.

In vivo quantification and pharmacokinetic studies of cotinine in mice after smoke exposure by LC-MS/MS

A sensitive analytical method was developed and validated for the quantification of cotinine in mouse plasma after exposure to smoke of 0.5, 1.0, and 1.5 commercially available cigarettes, using liquid chromatography tandem mass spectrometry. The method was validated over a linear concentration range of 0.075-20.0 ng/mL with the R² value being higher than 0.99. Both the precision (coefficient of variation; %) and accuracy (relative error; %) were within acceptable criteria of <15%. The lower limit of quantification (LLOQ) for cotinine was 0.075 ng/mL with sufficient specificity, accuracy, and precision. Following exposure to 0.5, 1.0, and 1.5 cigarette smoke, it was observed that the AUC and the C_max increased linearly as the doses increased. The pharmacokinetics of cotinine was found linear for the range of 0.5-1.5 commercial cigarette smoke. The quantification of the concentration of cotinine in mouse plasma after smoke exposure will facilitate future behavioral and toxicological experiments in animals and may prove useful in predicting cotinine levels in humans during smoking.

Accidental exposure to gas emissions from transit goods treated for pest control

BACKGROUND

International phytosanitary standards ISPM 15 require (since 2007) fumigation or heat treatment for shipping and storage. Those dealing with fumigated freight might be accidentally exposed. In this paper we report a series of three accidents of six storage room workers in a medium sized company regularly importing electronic production parts from abroad.

METHODS

Patients (n=6, aged from 32-54 yrs.) and control group (n=30, mean 40 yrs.) donated blood and urine samples. The fumigants: ethylene oxide, methyl bromide, chloropicrin, ethylene dichloride, other halo-alkanes and solvents were analyzed by headspace gas chromatography/mass spectrometry (GCMS). For the quantitation of long term exposure/s, macromolecular reaction products (hemoglobin adducts) were used (with GCMS) as molecular dosimeter; additionally 8-OHdG and circulating mtDNA (cmtDNA) were analyzed as nonspecific biological effect markers.

RESULTS

The hemoglobin adducts N-methyl valine (MEV) and N-(2-hydroxy ethyl) valine (HEV) were elevated after exposure to the alkylating chemicals methyl bromide and ethylene oxide. Under the consideration of known elimination kinetics and the individual smoking status (biomonitored with nicotine metabolite cotinine and tobacco specific hemoglobin adduct: N-(2 cyan ethyl) valines, CEV), the data allow theoretical extrapolation to the initial protein adduct concentrations at the time of the accident (the MEV/CEV levels were from 1,616 pmol/g globin to 1,880 pmol/g globin and HEV/CEV levels from 1,407 pmol/g globin to 5,049 pmol/g globin, and correlated with inhaled 0.4-1.5 ppm ethylene oxide. These integrated, extrapolated internal doses, calculated on the basis of biological exposure equivalents, confirmed the clinical diagnosis for three patients, showing severe intoxication symptoms. Both, cmtDNA and 8-OHdG, as non-specific biomarkers of toxic effects, were elevated in four patients.

CONCLUSION

The cases reported here, stress the importance of a suitable risk assessment and control measures. We put emphasis on the necessity of human biomonitoring guidelines and the urgency for the relevant limit values.

Microfluidic immunoassay for rapid detection of cotinine in saliva

A microfluidic immunoassay is successfully developed for rapid analysis of cotinine saliva samples, which is a metabolite of nicotine and is widely used as a biomarker to evaluate the smoking status and exposure to tobacco smoke. The core microfluidic chip is fabricated by polydimethylsiloxane (PDMS) with standard soft lithography. Each chip is capable of eight parallel analyses of cotinine samples. The analyses can be completed within 40 min with 12 μl sample consumption. The linear detection range is 1 ~ 250 ng/ml and the minimum detectable concentration is 1 ng/ml respectively. The correlation coefficient of the calibration curve established from standard samples is 0.9989. The immunoassay was also validated by real saliva samples, and the results showed good reproducibility and accuracy. All the results were confirmed with traditional ELISA measurements. The result from microfluidic chip device and ELISA kits showed good correspondence, and the correlation coefficients are higher than 0.99. Compared with traditional technique, this microfluidic immunoassay is more economic, rapid, simple and sensitive, perfect for on-site cotinine measurements as well as for the evaluation of the exposure to tobacco smoking. Moreover, this immunoassay has potential to be applied in the analysis of other biomarkers in human saliva samples.

Assessment of nicotine for second hand smoke exposure in some public places in Romania by UPLC-MS

BACKGROUND

Air nicotine monitoring is a well-known procedure for estimation of exposure to second hand smoke. Few research studies were realized in Romania to evaluate environmental tobacco smoke (ETS) exposure of humans in different public places. The levels of airborne nicotine from environmental tobacco smoke and urinary cotinine and nicotine levels of some subjects were analyzed. In order to better implement/enforce the European legislation regarding the interdiction of smoking in the public places the national authorities need a rapid and reliable analytical method to quickly asses the state of the pollution with cigarette smoke of these populated areas.

RESULTS

The nicotine concentration in the air from different types of public buildings was determined. The median concentration of nicotine in the air from 32 pubs where the smoking was allowed was 590 ng · L(-1), comparing with the pubs where the smoking was not permitted (22 locations) where the median concentration of nicotine was only 32 ng · L(-1). Similarly, the median concentration of nicotine in restaurants where the smoking was allowed (23 locations) was 510 ng · L(-1), in comparison with the restaurants where the smoking was prohibited (11 places) where the median value was 19 ng · L(-1). The lowest concentrations of nicotine were found in high schools (8 locations, median concentration 7.4 ng · L(-1)), universities (5 locations, 23 ng · L(-1)) and hospitals (6 locations, 16 ng · L(-1)).

CONCLUSIONS

The method was validated and gave good linearity, precision, accuracy and limit of detection. The buildings included hospitals, high schools, universities, pubs and restaurants. The presence of air nicotine was recorded in all buildings studied. The highest median levels of air nicotine were found in pubs and restaurants. The presence of air nicotine in indoor public buildings indicates weak implementation of the smoke free law in Romania.

Determination of thiocyanate (biomarkers of ETS) and other inorganic ions in human nasal discharge samples using ion chromatography

Environmental tobacco smoke (ETS) is a mixture of air and tobacco smoke containing more than 4000 chemical substances. In view of the health risks of many of these substances, studies are needed to determine biomarkers of exposure to ETS constituents in people who actively or passively are exposed to the toxic compounds. The methodologies for determining most biomarkers from saliva, urine and blood samples are known, but methods for analyzing these compounds in nasal discharges are not available. The objective of this work was to develop an analytical procedure for the determination of thiocyanate and other biomarker compounds in samples of nasal discharge using ion chromatography.

Circulating mitochondrial DNA as biomarker linking environmental chemical exposure to early preclinical lesions elevation of mtDNA in human serum after exposure to carcinogenic halo-alkane-based pesticides

There is a need for a panel of suitable biomarkers for detection of environmental chemical exposure leading to the initiation or progression of degenerative diseases or potentially, to cancer. As the peripheral blood may contain increased levels of circulating cell-free DNA in diseased individuals, we aimed to evaluate this DNA as effect biomarker recognizing vulnerability after exposure to environmental chemicals. We recruited 164 individuals presumably exposed to halo-alkane-based pesticides. Exposure evaluation was based on human biomonitoring analysis; as biomarker of exposure parent halo-methanes, -ethanes and their metabolites, as well as the hemoglobin-adducts methyl valine and hydroxyl ethyl valine in blood were used, complemented by expert evaluation of exposure and clinical intoxication symptoms as well as a questionnaire. Assessment showed exposures to halo alkanes in the concentration range being higher than non-cancer reference doses (RfD) but (mostly) lower than the occupational exposure limits. We quantified circulating DNA in serum from 86 individuals with confirmed exposure to off-gassing halo-alkane pesticides (in storage facilities or in home environment) and 30 non-exposed controls, and found that exposure was significantly associated with elevated serum levels of circulating mitochondrial DNA (in size of 79 bp, mtDNA-79, p = 0.0001). The decreased integrity of mtDNA (mtDNA-230/mtDNA-79) in exposed individuals implicates apoptotic processes (p = 0.015). The relative amounts of mtDNA-79 in serum were positively associated with the lag-time after intoxication to these chemicals (r = 0.99, p<0.0001). Several months of post-exposure the specificity of this biomarker increased from 30% to 97% in patients with intoxication symptoms. Our findings indicate that mitochondrial DNA has a potential to serve as a biomarker recognizing vulnerable risk groups after exposure to toxic/carcinogenic chemicals.

Tobacco smoke and pregnancy: segmental analysis of nicotine in maternal hair

The investigation assessed nicotine metabolism prior to and during pregnancy in relation to different maternal smoking habits. It included segmental hair analysis in 3 groups of postpartum women: 32 active smokers, 35 passive smokers, and 19 unexposed nonsmokers. Maternal hair at least 12 cm long was collected after delivery and was divided into four 3-cm-long segments representing each trimester of pregnancy and the 3 months prior to pregnancy. Hair nicotine concentration was determined by gas chromatography-mass spectrometry. Nicotine levels were the highest in the 3-month period before pregnancy and it gradually decreased with advancing gestation in all study groups. These results suggest that when assessing tobacco exposure as measured by nicotine in hair, metabolic changes of nicotine during pregnancy should be taken into consideration.

Environmental and biological monitoring of exposures to PAHs and ETS in the general population

The objective of this study was to analyse environmental tobacco smoke (ETS) and PAH metabolites in urine samples of non-occupationally exposed non-smoker adult subjects and to establish relationships between airborne exposures and urinary concentrations in order to (a) assess the suitability of the studied metabolites as biomarkers of PAH and ETS, (b) study the use of 3-ethenypyridine as ETS tracer and (c) link ETS scenarios with exposures to carcinogenic PAH and VOC. Urine samples from 100 subjects were collected and concentrations of monophenolic metabolites of naphthalene, fluorene, phenanthrene, and pyrene and the nicotine metabolites cotinine and trans-3'-hydroxycotinine were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to assess PAH and ETS exposures. Airborne exposures were measured using personal exposure samplers and analysed using GC-MS. These included 1,3-butadiene (BUT), 3-ethenylpyridine (3-EP) (a tobacco-specific tracer derived from nicotine pyrolysis) and PAHs. ETS was reported by the subjects in 30-min time-activity questionnaires and specific comments were collected in an ETS questionnaire each time ETS exposure occurred. The values of 3-EP (>0.25 microg/m(3) for ETS) were used to confirm the ETS exposure status of the subject. Concentrations as geometric mean, GM, and standard deviation (GSD) of personal exposures were 0.16 (5.50)microg/m(3) for 3-EP, 0.22 (4.28)microg/m(3) for BUT and 0.09 (3.03)ng/m(3) for benzo(a)pyrene. Concentrations of urinary metabolites were 0.44 (1.70)ng/mL for 1-hydroxypyrene and 0.88 (5.28)ng/mL for cotinine. Concentrations of urinary metabolites of nicotine were lower than in most previous studies, suggesting very low exposures in the ETS-exposed group. Nonetheless, concentrations were higher in the ETS population for cotinine, trans-3'hydroxycotinine, 3-EP, BUT and most high molecular weight PAH, whilst 2-hydroxyphenanthrene, 3+4-hydroxyphenanthrene and 1-hydroxyphenanthrene were only higher in the high-ETS subpopulation. There were not many significant correlations between either personal exposures to PAH and their urinary metabolites, or of the latter with ETS markers. However, it was found that the urinary log cotinine concentration showed significant correlation with log concentrations of 3-EP (R=0.75), BUT (R=0.47), and high molecular weight PAHs (MW>200), especially chrysene (R=0.55) at the p=0.01 level. On the other hand, low correlation was observed between the PAH metabolite 2-naphthol and the parent PAH, gas-phase naphthalene. These results suggest that (1) ETS is a significant source of inhalation exposure to the carcinogen 1,3-butadiene and high molecular weight PAHs, many of which are carcinogenic, and (2) that for lower molecular weight PAHs such as naphthalene, exposure by routes other than inhalation predominate, since metabolite levels correlated poorly with personal exposure air sampling.

Dipstick tests for secondhand smoke exposure

INTRODUCTION

We tested TobacAlert and NicAlert immunochromatographic strips for use as indicators of secondhand smoke (SHS) exposure.

METHODS

Urine samples collected from SHS-unexposed volunteers were spiked with cotinine to concentrations of 5, 8, 13, and 23 ng cotinine/ml urine. One sample was not spiked and used as a control. According to manufacturer's instructions, 45 NicAlert and 45 TobacAlert dipsticks were prepared. The exercise was repeated once. Cotinine levels in urine samples were measured using liquid chromatography/mass spectrometry (LC/MS). STATA was used for statistical analyses.

RESULTS

Ninety NicAlert and 90 TobacAlert dipsticks were tested. Each strip was read by 3 different readers, for 270 NicAlert and 270 TobacAlert readings; 98/270 (36%) NicAlert and 104/270 (39%) TobacAlert readings agreed with the readings predicted by LC/MS-determined cotinine levels. Spearman's rho for the NicAlert strips was .13 and for the TobacAlert strips .23. Both were statistically significant. Using a dichotomous scheme to interpret any strip reading >or=1 as "positive," indicating SHS exposure, NicAlert strips were 94% sensitive and 31% specific, while TobacAlert strips were 89% sensitive and 60% specific.

DISCUSSION

NicAlert and TobacAlert strips performed poorly at low cotinine levels. While the strips could be used to prescreen samples prior to more accurate testing, their use in the clinical or research setting to indicate SHS exposure should be restricted to carefully selected scenarios.

Determination of nicotine and cotinine in human serum by means of LC/MS

As part of a joint clinical research project to study the effects of nicotine on the brain, a HPLC electrospray ionisation mass spectrometry method with a solid-phase extraction sample preparation was developed for the quantitative determination of nicotine and cotinine in human serum in volunteers. The measured concentrations of nicotine and cotinine were used as control for smoking behaviour. A X-Bridge-column from Waters, and a SSQ 7000 single quadropole mass spectrometer with a TSP liquid chromatographic system were used. The method includes a simple and robust sample preparation and this assay has been shown to be of a sufficient sensitivity for this application. The limits of quantification were 5 and 2ng/ml for cotinine and nicotine, respectively. A simultaneous study was conducted to measure nicotine receptor availability and the vigilance in the same group of volunteers.

Enzyme-linked immunosorbent assay of nicotine metabolites

INTRODUCTION

The level of cotinine in biological specimens, such as serum, urine, and saliva, measured by gas or liquid chromatography is the most validated and reliable indicator of exposure to tobacco smoke. However, chromatographic methods are not always suitable for all types of situations.

METHODS

We validated a commercially available enzyme-linked immunosorbent assay (ELISA) that uses a polyclonal antibody to cotinine as a practical alternative to chromatographic methods.

RESULTS

The cotinine antibody cross-reacts to 3-hydroxycotinine (3HC) and its glucuronide, thus generating a value for immunoreactive (IR) cotinine, which is a complex comprising cotinine, 3HC, and 3HC-glucuronide. The levels of IR cotinine in the urine of kindergarten children closely correlated with those of cotinine measured by gas chromatography-mass spectrometry (GC-MS) and reflected the smoking behavior of their parents more precisely than cotinine levels determined by GC-MS.

DISCUSSION

Our findings showed that the cotinine-based ELISA can be a practical biomarker of exposure to tobacco smoke.

The assessment of environmental and occupational exposure to hazardous substances by biomonitoring

BACKGROUND

Modern biomonitoring has expanded beyond its origins in occupational medicine to cover a wide variety of diagnostic procedures and assessments of environmental pollution, ranging from exposure to heavy metals and chemicals to the effects of pesticides and environmental tobacco smoke. In biomonitoring, the overall pollutant load and hazardous exposure of an organism is quantitatively determined, by monitoring the pollutants themselves, their metabolic products and/or conjugates with protein or DNA, in either serum, urine or other body fluids, as well as tissue samples in exceptional circumstances.

METHODS

A selective survey of the current literature is exemplified by our recent scientific and clinical experience.

RESULTS

Biomonitoring is an excellent way to monitor potentially hazardous substances, especially for the assessment of systemic uptake from chronic exposure and the evaluation of subsequent health risks. Investigative biomonitoring can highlight incidental/accidental intoxication in individuals and provide new categories of problematic pollutants relevant to the general population.

CONCLUSIONS

In combination with diagnostic procedures, biomonitoring provides an important contribution to the rational assessment of currently recorded pollutants and resulting health risks. It is as an evaluation tool available in daily practice as well as in health and environmental research applications. Legislation is already implemented that incorporates biomonitoring within the remit of specified occupational health screening.

Urinary levoglucosan as a biomarker of wood smoke exposure: observations in a mouse model and in children

BACKGROUND

Biomass smoke is an important source of particulate matter (PM), and much remains to be discovered with respect to the human health effects associated with this specific PM source. Exposure to biomass smoke can occur in one of two main categories: short-term exposures consist of periodic, seasonal exposures typified by communities near forest fires or intentional agricultural burning, and long-term exposures are chronic and typified by the use of biomass materials for cooking or heating. Levoglucosan (LG), a sugar anhydride released by combustion of cellulose-containing materials, is an attractive candidate as a biomarker of wood smoke exposure.

OBJECTIVES

In the present study, Balb/c mice and children were assessed for LG in urine to determine its feasibility as a biomarker.

METHODS

We performed urinary detection of LG by gas chromatography/mass spectrometry after intranasal instillations of LG or concentrated PM (mice) or biomass exposure (mice or humans).

RESULTS

After instillation, we recovered most of the LG within the first 4 hr. Experiments using glucose instillation proved the specificity of our system, and instillation of concentrated PM from wood smoke, ambient air, and diesel exhaust supported a connection between wood smoke and LG. In addition, LG was detected in the urine of mice exposed to wood smoke. Finally, a pilot human study proved our ability to detect LG in urine of children.

CONCLUSIONS

These results demonstrate that LG in the lungs is detectable in the urine of both mice and humans and that it is a good candidate as a biomarker of exposure to biomass smoke.

Increased 8-isoprostane, a marker of oxidative stress in exhaled breath condensate in subjects with asbestos exposure

Asbestosis and pleural plaques exhibit unpredictable but progressive development, and there are no markers routinely available to measure their prognosis. Asbestos exposure induces the generation of reactive oxygen species, and 8-isoprostane is involved in experimental asbestos-related lung toxicity. This oxidative stress marker was measured in exhaled breath condensate (EBC) in 92 former asbestos workers with mean age 68.8+/-1.7 yr and mean duration of asbestos exposure 24.1+/-2.0 yr. The control group had 46 subjects with mean age 65.2+/-3.3 yr. The mean level of 8-isoprostane, analyzed by liquid chromatography-electrospray ionization-mass spectrometry, was higher in asbestos-exposed subjects (69.5+/-6.6 pg/ml, p=0.0001) compared with the control group, where the concentration was 47.0+/-7.8 pg/ml. The results presented support the hypothesis that oxidative stress due to asbestos is the main cause of increased 8-isoprostane in EBC. Measurement of 8-isoprostane in EBC is a promising non-invasive means for assessing the activity of asbestos-induced diseases.

Environmental tobacco smoke exposure in children in two districts of the Czech Republic

In the course of epidemiologic studies on the health of preschool children in the Teplice and Prachatice districts of the Czech Republic, we have recorded the frequency of smokers in the families of the children under study and the exposure of the children to environmental tobacco smoke (ETS) by assaying urinary cotinine levels. Questionnaires were administered at the age of 3 years (children born 1994-1996) or 4.5 years (children born 1997-1998). Out of 1128 respondents, 35.6% of the mothers and 48.9% of their husbands/partners were smokers. Taking into account other adult smokers, 41.6% of children lived in households without smokers and 30.1% in households with one smoker. There were more smokers among both mothers and fathers in Teplice than in the Prachatice district (mothers: 41.1% vs. 28.5%, P=0.017; fathers: 50.8% vs. 46.5%, NS). Cotinine concentration in the urine was determined using a radioimmunoassay in 523 pairs of mothers and children at the age of 4.5 years. A level higher than 500 ng cotinine per mg creatinine (our cut-off for active smoking) was detected in 199 out of 523 mothers (38%). Using 20 ng/mg as the cut-off, 48.2% of 523 children were exposed to ETS. There were more ETS-exposed children in Teplice than in the Prachatice district (59.2% vs. 34.7%, P<0.001). When cotinine levels were measured in 479 of these children at the age of 6-7 years, the percentage of children exposed to ETS decreased to 36.5%. However, the difference between Teplice and Prachatice children persisted (44.6% vs. 27.8%). Our results suggest that in the Czech Republic, children under 5 years of age are significantly exposed to tobacco smoke and that more effective regulatory measures are needed to decrease the prevalence of smoking.

Asthma attack associated with oxidative stress by exposure to ETS and PAH

Asthma is primarily an airways inflammatory disease, and the bronchial airways have been shown to be particularly susceptible to oxidant-induced tissue damage.

OBJECTIVE

The purpose of this study was to investigate whether pulmonary inflammation in asthma is associated with exposure to environmental oxidants such as polycyclic aromatic hydrocarbon (PAH) and environmental tobacco smoke (ETS).

METHOD

We assessed the exposure level of PAH and ETS by using urinary 1-hydroxypyrene glucuronide (1-OHPG) and cotinine. We estimated oxidative damage and inflammatory cytokine levels from 16 asthma patients and 16 patients in stable conditions 1 to 2 months later.

RESULTS

Our study showed that the levels of oxidative damage, as measured by malondialdehyde (MDA), were significantly increased (p = 0.006) during the asthma attacks. Proinflammatory and anti-inflammatory cytokines were both increased during the asthma attacks compared to the stable conditions at follow-up. Interleukin (IL-6) and IL-10 were especially increased significantly (p = 0.015 and p < 0.001, respectively). Correlations were observed between inflammatory cytokines such as IL-6 and IL-1beta (p = 0.034).

CONCLUSION

This study supports the results of in vitro studies that oxidative stress, specifically lipid peroxidation, contributes to the pathophysiology of asthma. Therefore, environmental interventions based on this better understanding are needed to significantly reduce oxidant stress and prevent or minimize the development of asthmatic symptoms.