Transcriptional pathways of elevated fasting blood glucose associated with short-term exposure to ultrafine particles: A panel study in Beijing, China

There is growing concern about the strong health effects of ultrafine particles (UFPs). However, less is known about the biological mechanisms. The objective of this study is to examine the association between short-term exposure to UFPs and fasting blood glucose (FBG) levels, and explore the potential physiological mechanisms at transcriptional levels. In a panel study of 135 participants, we measured FBG and the whole blood transcriptome repeatedly. The concentrations of ambient air pollutants were monitored continuously at a station. Linear mixed-effects models coupled with a mediating effect model were used to discriminate transcripts associated with air pollutant exposure and ln-transformed FBG levels. We found that FBG was significantly associated with interquartile range increase in the average UFPs concentrations 1-13 d prior to the clinical visits (ranging from 5.1% [95% CI 2.0-8.1%] in the 1-d time-window to 12.1% [95% CI 6.5-17.8%] in the 13-d time-window). Top 1000 transcripts associated with FBG increase following UFPs exposure were enriched into some biological pathways, such as pro-opiomelanocortin processing, negative regulation of hypoxia-inducible factor 1 A function, ubiquinone metabolism, and antigen presentation by major histocompatibility complex class I, classical pathway. These results suggest that elevated FBG associated with UFPs exposure may be related to regulation of metabolism, immune response, DNA damage, and apoptosis and survival.