Abstract 4139549: Air Filtration-Associated Changes in Cardiometabolic Protein Markers: Exploratory Analysis within a Randomized Controlled Trial

Background: Fine particulate matter air pollution (PM 2.5 ) exposure is linked with increased risk of cardiovascular disease (CVD) events, increases in blood pressure and inflammation. By decreasing PM 2.5 concentrations, portable air cleaners (PACs) reduce PM 2.5 exposure and may mitigate inflammatory responses to exposure. We hypothesized that PAC use is associated with changes in serum concentrations of protein biomarkers associated with CVD risk. Aim: We aimed to quantify changes in protein biomarkers after 4 weeks of PAC use to provide insights into the proteomic response to reduced PM 2.5 . Methods: We performed a randomized, double-blind, sham-controlled trial of PACs in 44 outpatient adults with stable HTN and no known CVD. Participants were randomly assigned to either the true PAC group or the sham PAC (placebo) group. Serum concentrations of 369 protein biomarkers associated with CVD risk were measured using the Olink Cardiometabolic Explore I panel before and after 4 weeks of PAC use. The associations between PAC use and changes in protein concentrations were analyzed using linear mixed-effects models, adjusting for age, sex and BMI. Results: Median (IQR) age of participants was 57.5 (51-68) years, 29 (66%) were female, and 21 (48%) had BMI > 30. The changes in expression of 7 protein biomarkers after air filtration differed significantly comparing true versus sham: SSC5D, F7, GH1, LEPR, TFPI, COL4A1, THPO (all p-values < 0.05 for interaction term). SSC5D and THPO were downregulated while the remainder were upregulated. PAC use may have beneficial effects on pathways associated with blood coagulation (increased F7 and TFPI, decreased THPO) and healing (increased LEPR, COL4A1, GH1) and innate immune response (decreased SSC5D). Though most of these have not been directly studied in relation to PM 2.5 , F7 has been shown to decrease with increased air pollution, concordant with our results. Conclusions: We showed significant effects of air filtration on serum concentrations of seven protein biomarkers linked with CVD. These results provide insight into potential mechanisms by which PAC use may reduce CVD risk.