Late Breaking Abstract - The impact of the reduction of environmental pollution during COVID-19 lockdown on healthy individuals (POLCOV Study)

Abstract

<b>Introduction:</b> Lockdown to combat COVID-19 pandemic produced a historic drop on air pollution in cities like Barcelona. This reduction offers a unique context to study the effects that air pollutants produce on the human health. The present study aims to determine and compare oxidative stress biomarkers and TH1/TH2/TH17-related cytokines in healthy individuals during lockdown and six months after easing mobility restrictions. <b>Methods:</b> Prospective study of a representative sample of 58 healthy, non-smoking adults. Age, sex, and postal district of residence were recorded in all individuals included in the study. On both visits, blood samples were drawn to analyse the percentage of eosinophils, levels of TH1/TH2/TH17-related cytokines by using a multiplex assay (BioRad), and levels of 8-isoprostane, (Cayman Chemical) as a biomarker of oxidative stress. <b>Results:</b> Six months after easing mobility restrictions, an increase in the levels of 8-isoprostane (p&lt;0.0001), G-CSF (p=0.0007), IL-1β (p=0.0013), IL-1ra (p=0.0110), IL-4 (p&lt;0.0001), IL-13 (p&lt;0.0001) and MIP-1α (p&lt;0.0001) and a decrease in the levels of IFN-γ (p=0.0145), TNFα (p&lt;0.0001), eotaxin (p&lt;0.0001), PDGF-BB (p&lt;0.0001), MIP-1β (p&lt;0.0001), IL-6 (p=0.0063), IL-7 (p&lt;0.0001) and RANTES (p&lt;0.0001) were found. No significant differences were observed in the percentage of eosinophils. The levels of the other cytokines were not detectable in both periods. <b>Conclusions:</b> The increase of environmental pollution after easing restrictions significantly increased the levels of oxidative stress and systemic inflammation. Study funded by FIS PI18/00344 (Instituto de Salud Carlos III) and FUCAP.