Olfactory cell cultures to investigate health effects of air pollution exposure: Implications for neurodegeneration.

Air pollution is a major, global public health concern. A growing body of evidence shows that exposure to air pollutants may impair the brain. Living in highly polluted areas has been linked to several neurodegenerative diseases, where exposure to complex mixtures of air pollutants in urban environments may have harmful effects on brain function. These harmful effects are thought to originate from elevated inflammation and oxidative stress. The olfactory epithelium is a key entry site of air pollutants into the brain as the particles are deposited in the upper airways and the nasal region. A potential source of patient-derived cells for study of air pollutant effects is the olfactory mucosa, which constitutes a central part of the olfactory epithelium. This review first summarizes the current literature on the available in vitro models of the olfactory epithelium. It then describes how alterations of the olfactory mucosa are linked to neurodegeneration and discusses potential therapeutic applications of these cells for neurodegenerative diseases. Finally, it reviews the research performed on the effects of air pollutant exposure in cells of the olfactory epithelium. Patient-derived olfactory epithelial models hold great promise for not only elucidating the molecular and cellular pathophysiology of neurodegenerative disorders, but for providing key understanding about air pollutant particle entry and effects at this key brain entry site.

Altered expression of HSP27 and HSP70 in distal oesophageal mucosa in patients with gastro-oesophageal reflux disease subjected to fundoplication.

BACKGROUND: Gastro-oesophageal reflux disease (GERD) is a risk factor for oesophageal adenocarcinoma. Although fundoplication cures reflux symptoms and oesophagitis, it remains controversial whether it is capable of preventing the development of oesophageal adenocarcinoma. Hsp27 and Hsp70 are associated with the development of cancer, whereas the effect of fundoplication on them is not known. METHODS: The expression of Hsp27 and Hsp70 was assessed semiquantitatively from biopsies of oesophageal mucosa for a prospective cohort of 19 patients with GERD treated with fundoplication and 7 controls without GERD. Upper gastrointestinal endoscopy with biopsies from the oesophagogastric junction (EGJ) and the distal and proximal oesophagus were performed preoperatively (19 patients) and after recovery from GERD at 6 (19 patients) and 48 months (16 patients) postoperatively. RESULTS: The expressions of both Hsp27 (p = 0.001) and Hsp70 (p = 0.002) in the distal oesophagus were lower in patients preoperatively and at 48 months postoperatively (p < 0.001 for both) than in controls. The patients' Hsp27 and Hsp70 levels were lower preoperatively in the proximal oesophagus (p = 0.048 for both) than in controls. Both Hsp27 (p = 0.002) and Hsp70 (p = 0.003) were lower in the distal oesophagus preoperatively and at 48 months postoperatively (p = 0.003 for Hsp27, p = 0.004 for Hsp70) than in the proximal oesophagus. CONCLUSIONS: Our results indicate that there may be some factor interfering with the mucosal defence system of the distal oesophagus in GERD that is uninfluenced by fundoplication and not associated with the acid-reflux-normalizing effect.

Comparison of pressurized fluid extraction, Soxhlet extraction and sonication for the determination of polycyclic aromatic hydrocarbons in urban air and diesel exhaust particulate matter.

In order to characterize and compare the chemical composition of diesel particulate matter and ambient air samples collected on filters, different extraction procedures were tested and their extraction efficiencies and recoveries determined. This study is an evaluation of extraction methods using the standard 16 EPA PAHs with HPLC fluorescence analysis. Including LC analysis also GC and MS methods for the determination of PAHs can be used. Soxhlet extraction was compared with ultrasonic agitation and pressurized fluid extraction (PFE) using three solvents to extract PAHs from diesel exhaust and urban air particulates. The selected PAH compounds of soluble organic fractions were analyzed by HPLC with a multiple wavelength shift fluorescence detector. The EPA standard mixture of 16 PAH compounds was used as a standard to identify and quantify diesel exhaust-derived PAHs. The most effective extraction method of those tested was pressurized fluid extraction using dichloromethane as a solvent.

Time- and dose-dependent DNA binding of PAHs derived from diesel particle extracts, benzo[a]pyrene and 5-methychrysene in a human mammary carcinoma cell line (MCF-7).

Cultures of a human mammary carcinoma cell line (MCF-7) were exposed to the soluble organic fraction of diesel particle emissions, benzo[a]pyrene (B[a]P) and 5-methylchrysene (5-MeCHR) to study time- and dose-related PAH-DNA binding. The concentrations of 14 PAHs in three extracts were analyzed by HPLC and PAH-DNA adducts were measured by (32)P post-labeling assay. Time-dependent DNA adducts formation of 2.5 microM B[a]P was lower than that of 2.5 microM 5-MeCHR. In comparison with B[a]P, 2-fold higher adduct formation by 5-MeCHR was observed at 12 h exposure, after which BPDE adducts decreased and 5-MeCHR continued to form adducts linearly during 48 h exposure. The data for these two PAH compounds demonstrate a large variation in adduct-forming potency, which should be taken into account when estimating DNA adducts formed by mixtures of unknown PAHs. A clear dose-response effect on formation of DNA adducts was obtained for B[a]P and a Standard Reference Material (SRM) of diesel particulate matter. The amount of B[a]P contributed more to total DNA adduct formation by SRM than by three diesel extracts. Thus, no conclusions can be drawn from diesel particle-derived B[a]P as to the adduct-forming potency of other carcinogenic PAHs. There was little change in adduct levels formed by three diesel extracts from 0 to 12 h exposure. Thereafter, the number of adducts formed by RD2 increased more rapidly than those formed by RD1 and EN97. The concentrations of 14 PAHs and adduct levels analyzed at 24 and 48 h did not change in the same proportion between the extracts. Neither could PAH-DNA adduct levels be explained by the sum of strong and weak adduct-forming PAHs analyzed in the extracts. This indicates that other PAHs in the extracts RD1, RD2 and EN97 contributed to adduct formation more than the carcinogenic adduct-forming PAHs analyzed in this study.