Effects Of Size-fractioned Ambient Particulate Matter On Circulating Biomarkers In Type 2 Diabetics

Background Toxicological studies generated several potential mechanisms in relation to particulate matter (PM) injuries, among which inflammation and oxidative stress are the most developed and promising one. Numerous epidemiological studies suggest that many patients with diabetes are sensitive to atmospheric PM. However, it is still inconclusive that what the health effects caused by different PM size and what the time mode of action of PM.Objectives ① To investigate whether short-term exposure to size-fractioned PM have effects on circulating biomarkers of inflammation, coagulation and vasoconstriction. ② To investigate which size of PM has the stronger health effect; ③ Assess the time mode of action of PM with different size.Methods We recruited 35 patients with type 2 diabetes in the Tianping Street in Xuhui District, Shanghai, according to the inclusion and exclusion criteria. Blood plasma biomarkers were measured biweekly over 6 times and included 7 markers of inflammation [CRP (C-reactive protein)、ICAM-1 (intercellular adhesion molecule-1)、VCAM-1 (vascular cell adhesion molecule-1)、P-selection、MCP-1 (monecyte chemoattractant protein-1)、IL-1b (interleukin-1b)、TNF-α (tumor necrosis factor-a)],4 of coagulation [Fibrinogen、PAI-1 (plasminogen activator inhibitor-1)、sCD40L (souble CD40 ligand). vWF (von Willebrand factor)] and 1 of vasoconstriction [endothelin-1 (ET-1)]. Real-time number concentrations of PM with aerodynamic diameters in the range of 0.25 μm-1.0 μm were measured over the follow-ups. We used linear mixed-effect model to examine the association of size-fractioned PM with the concentrations of these plasma biomarkers. We also examined whether the different lag time of PM exposure had different health effects.Results We recruited a total of 35 diabetics (17 males and 18 females), with an average of 66 years old. Regression analysis showed that short-term exposure of PM was associated with most circulating indicators of inflammation, blood coagulation and vasoconstriction. These findings also suggested that PM with smaller size had stronger effects. Take CPR as an example, it increased by 19.44% [95% confidence interval (CI):2.84%,36.04%] with an interquartile range (IQR; 372,424 (1/L)) increase in particulate number concentration for 0.25-0.28 um (PNC0.25-0.28) over lag of 2h, whereas it increased by 11.36% (95% CI:2.22%,20.5%) with an IQR [2,810 (1/L)] increase in PNC0.80-1.0 over lag of 2h. Furthermore, our results demonstrated a very acute effect on circulating biomarkers even 2 hours after the exposure, and it last for 6-12h for inflammation and vasoconstriction indicators,12-24h for blood coagulation indicators. When NO2 or SO2 was added in the regression models, the effects were similar with what singal pollutant model showed.Conclusions ① Short-term exposure of size-fractioned PM had effects on some circulating indicators of inflammation (CRP etc.), blood coagulation (Fibrinogen etc.) and vasoconstriction (ET-1 etc.). ② PM with smaller size had stronger effects. ③ PM had a very acute effect on circulating biomarkers even 2 hours after exposure, and it last for 6-12h for inflammation and vasoconstriction indicators,12-24h for blood coagulation indicators.