A Soluble Form of the Triggering Receptor Expressed on Myeloid Cells-1 Modulates the Inflammatory Response in Murine Sepsis

The triggering receptor expressed on myeloid cells (TREM)-1 is a recently discovered receptor expressed on the surface of neutrophils and a subset of monocytes. Engagement of TREM-1 has been reported to trigger the synthesis of proinflammatory cytokines in the presence of microbial products. Previously, we have identified a soluble form of TREM-1 (sTREM-1) and observed significant levels in serum samples from septic shock patients but not controls. Here, we investigated its putative role in the modulation of inflammation during sepsis. We observed that sTREM-1 was secreted by monocytes activated in vitro by LPS and in the serum of animals involved in an experimental model of septic shock. Both in vitro and in vivo, a synthetic peptide mimicking a short highly conserved domain of sTREM-1 appeared to attenuate cytokine production by human monocytes and protect septic animals from hyper-responsiveness and death. This peptide seemed to be efficient not only in preventing but also in down-modulating the deleterious effects of proinflammatory cytokines. These data suggest that in vivo modulation of TREM-1 by sTREM peptide might be a suitable therapeutic tool for the treatment of sepsis

Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers

<p>Abstract</p> <p>Background</p> <p>This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma.</p> <p>Methods</p> <p>Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM_2.5and PM₁₀personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period.</p> <p>Results</p> <p>Bakery apprentices experience greater average PM_2.5and PM₁₀exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM₁₀values among bakers = 1.10 mg.m^-3[standard deviation: 0.83]) than in summer (0.63 mg.m^-3[0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m^-3). Over half the facilities had no ventilation system.</p> <p>Conclusion</p> <p>Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.</p

Maternal exposure to air pollution before and during pregnancy related to changes in newborn's cord blood lymphocyte subpopulations. The EDEN study cohort

<p>Abstract</p> <p>Background</p> <p>Toxicants can cross the placenta and expose the developing fetus to chemical contamination leading to possible adverse health effects, by potentially inducing alterations in immune competence. Our aim was to investigate the impacts of maternal exposure to air pollution before and during pregnancy on newborn's immune system.</p> <p>Methods</p> <p>Exposure to background particulate matter less than 10 μm in diameter (PM₁₀) and nitrogen dioxide (NO₂) was assessed in 370 women three months before and during pregnancy using monitoring stations. Personal exposure to four volatile organic compounds (VOCs) was measured in a subsample of 56 non-smoking women with a diffusive air sampler during the second trimester of pregnancy. Cord blood was analyzed at birth by multi-parameter flow cytometry to determine lymphocyte subsets.</p> <p>Results</p> <p>Among other immunophenotypic changes in cord blood, decreases in the CD4+CD25+ T-cell percentage of 0.82% (p = 0.01), 0.71% (p = 0.04), 0.88% (p = 0.02), and 0.59% (p = 0.04) for a 10 μg/m³increase in PM₁₀levels three months before and during the first, second and third trimester of pregnancy, respectively, were observed after adjusting for confounders. A similar decrease in CD4+CD25+ T-cell percentage was observed in association with personal exposure to benzene. A similar trend was observed between NO₂exposure and CD4+CD25+ T-cell percentage; however the association was stronger between NO₂exposure and an increased percentage of CD8+ T-cells.</p> <p>Conclusions</p> <p>These data suggest that maternal exposure to air pollution before and during pregnancy may alter the immune competence in offspring thus increasing the child's risk of developing health conditions later in life, including asthma and allergies.</p