African Dust Storms Reaching Puerto Rican Coast Stimulate the Secretion of IL-6 and IL-8 and Cause Cytotoxicity to Human Bronchial Epithelial Cells (BEAS-2B)

Abstract

African dust storm events (ADE) travel across the Atlantic Ocean (ADEAO) and reach the Puerto Rican coast (ADEPRC), potentially impacting air quality and human health. To what extent seasonal variations in atmospheric particulate matter (PM) size fractions, composition and sources trigger respiratory-adverse effects to Puerto Ricans is still unclear. In the present study, we investigated the pro-inflammatory and cytotoxic effects of PM samples harvested during ADEAO (PM10), ADEPRC (PM2.5 and PM10) and Non-ADE (Preand Post-ADEAO and Non-ADEPRC), using BEAS-2B cells. Endotoxins (ENX) in PM2.5 and PM10 extracts and traces of metals (TMET) in PM2.5 extracts were also examined. IL-6 and IL-8 secretion and cytotoxicity were used as endpoints. ADEAO and ADEPRC extracts were found to be more cytotoxic than Non-ADE and ADEAO were more toxic than ADEPRC extracts. PM10 extracts from ADEAO and Post-ADEAO caused significant secretion of IL-8. IL-6 and IL-8 secretion was higher following treatment with PM10 and PM2.5 ADEPRC than with Non-ADEPRC extracts. ENX levels were found to be higher in PM10 ADEAO than in the rest of the samples tested. TMET levels were higher in PM2.5 ADEPRC than in Non-ADEPRC extracts. Deferoxamine significantly reduced cytotoxicity and IL-6 and IL-8 secretion whereas Polymyxin B did not. TMET in PM2.5 fractions is a major determinant in ADEPRC-induced toxicity and work in conjunction with ENX to cause toxicity to lung cells in vitro. ENX and TMET may be responsible, in part, for triggering PM-respiratory adverse responses in susceptible and predisposed individuals.

Biodiesel from soybean promotes cell proliferation in vitro

“…The Neutral Red bioassay was used to measure cell viability as previously described (Rodríguez-Cotto et al, 2013). Briefly, after a 24 h cell exposure to biodiesel extracts, the treatments were removed and BEAS-2B cells were incubated with Neutral Red dye (Sigma, Cat No N2889) at a final concentration of 100 μg mL -1 for 3 h. The dye was then removed; cells were fixed in 1 % calcium chloride, 0.5 % formaldehyde, rinsed with phosphate buffered saline (PBS) and lysed using 1 % acetic acid and 50 % ethanol.…”

Organic extracts from African dust storms stimulate oxidative stress and induce inflammatory responses in human lung cells through Nrf2 but not NF-κB

“…The PR-EQB has designated station EQB 22 as a remote site to measure African dust minimizing the contribution of other local sources of particulate matter. The samples were classified according to the corresponding collection day, as ADE and Non-ADE utilizing satellite images in conjunction with ground field data of PM 2.5 weights provided by PR-EQB (Rodríguez-Cotto et al, 2013). Two organic extracts were prepared using a Soxhlet extraction apparatus for 48 hr (Molinelli et al, 2006).…”

“…Extracts were stored at −20°C. These samples were previously analyzed for metal composition (Al, Fe, Cd, Cu, Pb and V), cytotoxicity and interleukins (IL-6, IL-8, IL-1β, TNF-α and GM-CSF) concentration (Rodríguez-Cotto et al, 2013). …”

“…Cells were exposed to PM 2.5 extracts at a concentration of 50 μg/ml for 1–14 hr depending on the assay. The extract concentration of 50 μg/ml was selected from a previous cytotoxicity assay (Rodríguez-Cotto et al, 2013). This concentration was not toxic to the cells.…”

“…Data obtained from the Puerto Rico’s Health Insurance Administration reported an increase in asthma cases for children ≤5 yrs of age during the dust season considered in the present study. Many metals (Al, Cu, Fe, Pb and V) have been reported to increase in association to the advent of African dust storms (Gioda et al, 2007; Jiménez et al, 2009; Rodríguez-Cotto et al, 2013). In 2004 17% of PR PM 2.5 was composed of metals (Puerto Rico Environmental Quality Board, 2005).…”