Roflumilast increases Clara cell secretory protein in cigarette smoke-exposed mice.

Decreased Clara cell secretory protein (CCSP) levels have been found in smokers and chronic obstructive pulmonary disease (COPD) patients, which may be related to the development of COPD. A phosphodiesterase-4 (PDE4) inhibitor, roflumilast, appears to have therapeutic value for COPD. However, its effect on CCSP in cigarette smoke (CS)-exposed lungs has not been investigated. AKR/J mice were treated as follows: air control, CS, roflumilast plus CS, and roflumilast. Mice underwent four weeks of air or CS exposure. Roflumilast was administrated at 5mg/kg via gavage once daily for the duration of the study. CCSP levels in bronchoalveolar lavage (BAL) fluid and ERK1/2 activation in lungs were examined. CS exposure tended to decrease CCSP levels in BAL fluid compared to air controls. Treatment with roflumilast significantly reversed CS-induced downward trend of CCSP in BAL fluid. Roflumilast significantly inhibited CS-induced upward trend of ERK1/2 activation in lungs, and the levels of activated ERK1/2 in lungs negatively correlated with CCSP levels of BAL fluid in CS, and CS plus roflumilast groups. Our results demonstrate that one of the therapeutic mechanisms of roflumilast is to reverse CS-induced downward trend in CCSP levels of BAL fluid, which may be mediated by down-regulating ERK1/2 activity.

Modulation of pulmonary inflammatory responses and antimicrobial defenses in mice exposed to diesel exhaust.

Diesel exhaust (DE) is a major component of urban air pollution and has been shown to increase the severity of infectious and allergic lung disease. The purpose of this study was to evaluate the effects of DE exposure on pulmonary inflammation, mediator production and antimicrobial defenses in an exposure model that had previously been shown to increase susceptibility to influenza. BALB/c mice were exposed to filtered air, or to DE diluted to yield 0.5 or 2 mg/m(3) of diesel exhaust particles (DEP) for 4 h per day for 1 or 5 days. Immediately and 18 h after one or five diesel exposures mice were euthanized to assess both immediate and delayed effects. DE exposure for 5 days at either concentration caused higher neutrophil numbers and lesion scoring compared to air controls. Intracellular adhesion molecule-1 (ICAM-1), which recruits inflammatory cells and is an entry site for rhinoviruses was increased immediately after 1 or 5 days of DE exposure. Several inflammatory and immune cytokines (TNF-alpha, MIP-2, IL-6, IFN-gamma, and IL-13) were also upregulated at various time points and concentrations. In contrast, clara cell secretory protein (CCSP), surfactant protein A (SP-A), and surfactant protein D (SP-D) which are important host defense molecules, were significantly decreased at both the message and protein level with DE exposure. We conclude that exposure to moderate and high occupational levels of DE caused an increase in lung injury and inflammation, and a decrease in host defense molecules, which could result in increased susceptibility to respiratory pathogens.

Inhalation of concentrated particulate matter produces pulmonary inflammation and systemic biological effects in compromised rats.

Although significant progress has been made over the past few years, there is still debate on the causal fractions that are responsible for particulate matter (PM)-associated adverse health effects. A series of 1-d inhalation exposures to concentrated ambient particles (CAPs) were performed in compromised rats, focusing on pulmonary inflammation and changes in blood factors as biological outcomes. Studies were carried out in The Netherlands at an urban background location in Bilthoven, an industrialized location in the city of Utrecht, as well as at a location that is heavily dominated by freeway emissions. It was hypothesized that exposure to CAPs resulted in oxidative stress in the lung, producing a release of inflammatory mediators, which in turn can result in cardiovascular effects. Both spontaneously hypertensive rats and rats preexposed to ozone were studied. The effects were studied at 2d postexposure, focusing on pathology and cell proliferation, bronchoalveolar lavage fluid (BALF) analysis (including cytokines, biochemistry, cell differentials, cell viability and proliferation, and Clara-cell 16 protein), and blood analyses (fibrinogen, Clara-cell 16 protein, Von Willebrand factor, and cell differentials). Using CAPs exposures as a binary term, mild inflammation (increased numbers of neutrophils) and increased lung permeability (protein and albumin leakage in BALF) were evident. In addition, CAPs also produced increased fibrinogen concentrations in blood of spontaneously hypertensive rats. In conclusion, inhalation up to 3700 microg/m3 CAPs in the size range of 0.15-2.5 microm did induce statistically significant effects in the lung and blood, but the effects observed may not potentially be very biologically relevant. PM mass concentrations and lung permeability were weakly associated. This suggests that other PM metrics might be more appropriate.

Modulation of endometrial transformation in gonadotrophin-stimulated and unstimulated pseudo-pregnant rabbits: studies with the progesterone receptor antagonist, onapristone.

Advanced endometrial transformation often occurs in IVF and embryo transfer therapy after ovarian stimulation with gonadotrophins. One reason is probably the early rise in peripheral progesterone concentration after ovulation induction. Consequently, we studied in a rabbit model, whether the post-ovulatory application of the progesterone receptor antagonist, onapristone, could prevent such an advancement of endometrial transformation after stimulation with different gonadotrophin preparations. The inhibitory effect of onapristone on the endometrium is dependent upon the strength of ovarian stimulation. In unstimulated animals or animals treated with recombinant LH (nine corpora lutea/animal in both groups), secretory differentiation and proliferation of the endometrium was strongly inhibited by onapristone. After weak ovarian stimulation with a 3:1 mixture of FSH and LH (22 corpora lutea/animal), secretory differentiation was strongly inhibited, while proliferation was enhanced. After strong stimulation with either a 1:1 mixture of FSH and LH, or human menopausal gonadotrophin (HMG; >40 corpora lutea/animal), only limited inhibitory effects of onapristone on secretory transformation or proliferation could be detected. In conclusion, these graded effects of onapristone after stimulation with gonadotrophins, resemble the basic observations from which a therapeutic strategy emerges, to modulate the advanced endometrial transformation which occurs in many IVF patients after ovarian stimulation.