Modeling the influence of vitamin D deficiency on cigarette smoke-induced emphysema.

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. While the primary risk factor for COPD is cigarette smoke exposure, vitamin D deficiency has been epidemiologically implicated as a factor in the progressive development of COPD-associated emphysema. Because of difficulties inherent to studies involving multiple risk factors in the progression of COPD in humans, we developed a murine model in which to study the separate and combined effects of vitamin D deficiency and cigarette smoke exposure. During a 16-week period, mice were exposed to one of four conditions, control diet breathing room air (CD-NS), control diet with cigarette smoke exposure (CD-CSE), vitamin D deficient diet breathing room air (VDD-NS) or vitamin D deficient diet with cigarette smoke exposure (VDD-CSE). At the end of the exposure period, the lungs were examined by a pathologist and separately by morphometric analysis. In parallel experiments, mice were anesthetized for pulmonary function testing followed by sacrifice and analysis. Emphysema (determined by an increase in alveolar mean linear intercept length) was more severe in the VDD-CSE mice compared to control animals and animals exposed to VDD or CSE alone. The VDD-CSE and the CD-CSE mice had increased total lung capacity and increased static lung compliance. There was also a significant increase in the matrix metalloproteinase-9: tissue inhibitor of metalloproteinases-1 (TIMP-1) ratio in VDD-CSE mice compared with all controls. Alpha-1 antitrypsin (A1AT) expression was reduced in VDD-CSE mice as well. In summary, vitamin D deficiency, when combined with cigarette smoke exposure, seemed to accelerate the appearance of emphysemas, perhaps by virtue of an increased protease-antiprotease ratio in the combined VDD-CSE animals. These results support the value of our mouse model in the study of COPD.

Exposure to Cigarette Smoke Disrupts CCL20-Mediated Antimicrobial Activity in Respiratory Epithelial Cells.

Cigarette smoke (CS) exposure is known to increase infection rates, but the mechanisms are not well understood. These studies tested the hypothesis that CS exposure would impair antimicrobial activity of apical conditioned media from human airway (BEAS-2B) cultures by reducing induction and release of the antimicrobial peptide CCL20. BEAS-2B cultures were exposed to CS extract and assayed for temporal and physical characteristics of release as well as for antimicrobial activity. E. coli were exposed to Beas-2B-conditioned media (BCM) and subsequent bacterial colonies were enumerated. In time course studies TLR-agonist-induced CCL20 transcription and release were rapid, of short duration and release was consistently targeted to the apical/luminal compartment. Cells treated with CS extract had diminished release of CCL20 under both constitutive and toll-like receptor (TLR) agonist stimulating conditions. Exposure of the cells to CS significantly reduced the antimicrobial activity in BCM and neutralizing antibodies to CCL20 brought antibacterial activity back to baseline levels demonstrating that antimicrobial activity in this culture system was primarily attributable to CCL20. These studies add to the understanding of CCL20 as a mucosal antimicrobial and improve insight into a likely mechanism linking infection to CS exposure.

Elevated concentrations of ethinylestradiol, 17beta-estradiol, and medroxyprogesterone have little effect on reproduction and survival of Ceriodaphnia dubia.

Wastewater effluent contains synthetic and natural hormones, often in complex mixtures, that may be associated with reproductive abnormalities in fish and other aquatic biota. We exposed the sentinel invertebrate Ceriodaphnia dubia to the natural estrogen 17beta-estradiol (E(2)), a synthetic estrogen, ethinylestradiol (EE(2)), and a synthetic progestin, medroxyprogesterone in a 7-day test. These compounds had no significant effect on reproduction or survival even at 10(6) times the concentrations at which reproductive effects have been documented in several fish species. C. dubia is routinely used for screening the toxicity of wastewater effluent. However, in the standard chronic 7-day exposure the endpoints of survival and reproduction were insensitive to several synthetic and natural vertebrate hormones. The C. dubia 7-day chronic toxicity test is probably not a useful monitoring tool for vertebrate hormones and their pharmaceutical analogs unless other sensitive endpoints such as maturation rates, molt frequency, and offspring sex ratios are incorporated in a practical manner.

The effects of environmentally relevant mixtures of estrogens on Japanese medaka (Oryzias latipes) reproduction.

Wastewater effluent contains a variety of estrogenic compounds that vary in potency, but each of which contributes to the overall estrogenicity of the effluent. We hypothesized that the effects of mixtures of estrogens on reproduction in pair breeding medaka (Oryzias latipes) could be predicted by their relative estrogenicity. Relative estrogenicity was defined by the ability of estrogenic compounds to induce vitellogenesis in various species of male fish. We exposed reproducing pairs of medaka to mixtures of the environmental estrogens nonylphenol (NP), 17alpha-ethinylestradiol (EE(2)), and natural 17beta-estradiol (E(2)), as well as treatments of equivalent estrogenicity that were composed of E(2) alone. Reproducing medaka exposed to mixtures of estrogenic compounds and equipotent treatments of estradiol alone had very similar responses in mortality and reproduction (fecundity, number of spawns). However, mixtures of NP, E(2), and EE(2) elicited lower vitellogenic induction than equipotent concentrations of E(2) alone. Therefore, relative estrogenicity was a good model for predicting some, but not all, reproductive responses, and simple additive mixture models may not predict all relevant physiological responses.