Effect of Ambient Fine Particulate Matter Air Pollution and Colder Outdoor Temperatures on High-Density Lipoprotein Function

Abstract

Fine particulate matter (PM) air pollution and environmental temperatures influence cardiovascular morbidity and mortality. Recent evidence suggests that several air pollutants can promote dyslipidemia; however, the impact of ambient PM and temperature on high-density lipoprotein (HDL) function remains unclear. We hypothesized that daily exposures to higher levels of ambient PM and colder outdoor temperatures would impair HDL functionality. Lipoproteins, serum cholesterol efflux capacity (CEC), and HDL oxidation markers were measured twice in 50 healthy adults (age 32.1 ± 9.6 years) living in southeast Michigan and associated with ambient and personal-level exposures using mixed models. Although previous 7-day mean outdoor temperature (4.4 ± 9.8°C) and PM levels (9.1 ± 1.8 µg/m) were low, higher ambient PM exposures (per 10 µg/m) were associated with significant increases in the total cholesterol-to-HDL-C ratio (rolling average lag days 1 and 2) as well as reductions in CEC by -1.93% (lag day 5, p = 0.022) and -1.62% (lag day 6, p = 0.032). Colder outdoor temperatures (per 10°C) were also associated with decreases in CEC from -0.62 to -0.63% (rolling average lag days 5 and 7, p = 0.027 and 0.028). Previous 24-hour personal-level PM and temperature exposures did not impact outcomes, nor were any exposures associated with changes in HDL-oxidation metrics. In conclusion, we provide the first evidence that ambient PM (even at low levels) and outdoor temperatures may influence serum CEC, a critical antiatherosclerotic HDL function.

Advances in HDL: Much More than Lipid Transporters

“…[86]. Moreover, the presence of cardiovascular risk factors, including hypercholesterolemia [13,60,87], obesity [88], diabetes type 1 and 2 [89,90], and even frequent exposure to pollution [91][92][93] or ethnicity have demonstrated to impact HDL properties and induce structural changes leading to variations in their subtypes profile. Altogether, these conditions may help explain the disappointing results observed in clinical trials aiming to increase HDL-c levels in secondary prevention.…”

Effects of particulate matter on atherosclerosis: a link via high-density lipoprotein (HDL) functionality?

“…The current literature on PM-exposure and HDL functionality suggest that fine and ultrafine PM may impair functional properties of HDL via oxidative pathways [27,28,[30][31][32][33]. Accumulating evidence links particles to atherosclerosis, in particular those with a high amount of organic chemicals [3,6,31,36].…”

“…Results from a study by Mathew et al showed that exposure to even low levels of PM 2.5 (9,1 ± 1,8 μg/m 3 ) for a short period of time were linked to an impaired HDL functionality measured as cholesterol efflux capacity (n = 50) [27]. In the Beijing AIRCHD study, participants were followed up with 4 study visits in a 14-month period (n = 73).…”

“…Oxidized Apo-AI is unable to activate lecithin cholesterol acyltransferase (LCAT) which is important for increasing the cholesterol efflux capacity [17,62]. However, reduced HDL functionality without a corresponding increase in myeloperoxidase activity has been reported [27].…”

Urban Particulate Matter Enhances ROS/IL-6/COX-II Production by Inhibiting MicroRNA-137 in Synovial Fibroblast of Rheumatoid Arthritis

“…Of particular concern is the ambient fine particulate matter (PMs), a mixture of multiple components (such as metals, water-soluble ions, polycyclic aromatic hydrocarbons [PAHs] and organic carbons, etc.) and diversified sources (such as coal combustion, ground dust, biomass burning and vehicle exhaust) with high oxidative potential and small aerodynamic diameter (less than 2.5 micrometers) that can penetrate deep into the pulmonary microvascular system and affect various organ systems [14,15]. PMs are found to cause detrimental inflammation on various target organs through producing reactive oxygen species (ROS) [16][17][18].…”