Are miRNAs a link between air pollution exposure and cardiovascular changes?

Abstract

Retinal arteriolar narrowing and retinal venular widening are risk factors for cardiovascular disease. Increases in inflammation, oxidative stress and endothelial dysfunction are processes, present in the development of cardiovascular disease that could initiate microvascular changes. The underlying molecular mechanisms behind these microvascular changes remain unclear. Recently, the analysis of miRNA expression patterns revealed that miRNAs are associated with air pollution exposure. This master thesis examined the effect of both acute and short-term air pollution exposure on miR-21, miR-222 and miR-146a expression patterns and the relationship with microvascular changes. By mean of fundus image analysis together with mixed-effect model analysis associations were demonstrated. First, acute PM2.5 and PM10 exposure levels together with short-term PM10 exposure levels are associated with arteriolar narrowing. Furthermore, acute PM2.5 and PM10 as well as short-term PM10 exposure levels showed a trend towards an association with venular widening. Second, short-term PM10 exposure levels are associated with a downregulation of miR-21 and miR-222, more particularly miRNAs involved in inflammation, oxidative stress and endothelial dysfunction. Third, a 10% increase of miR-146a and miR-222 are associated with a decrease in CRVE. These findings demonstrated that miRNAs may be a molecular trigger through which PM particles can cause changes in the microcirculation and induce cardiovascular disease.