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Table 2 Clinical trials on PM exposure and HDL functionality

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

Author, year and country

Design

Study population

Air pollutant

Exposure

Outcome

Results

Main findings

Maiseyeu et al. 2014, United States [29]

Randomized double-blinded crossover study

Country: United States

Age: 18–50 y (25.9 ± 6.6 y)

Non-smoking adults without established CV disease or traditional CV risk factors

n = 32 (16 female subjects)

PM10–2.5

Coarse concentrated ambient particles (CAP) [76,2 ± 51,5 μg/m3] in a rural location and filtered air (FA) for 2 h.

HDL mediated cholesterol efflux capacity (CEC)

HDL antioxidant capacity (measured as HDL oxidation index (HOI))

Paraoxonase (PON) activity

There were no significant differences detected in CEC metrics to HDL from subjects exposed 2 h or 20 h following CAP versus FA exposures.

HOI and PON activity did not differ 20-h post-CAP versus FA, respectively.

Brief inhalation of high levels of coarse PM did not acutely impair several facets of HDL functionality (CEC, HOI, PON activity).

Ramanathan et al. 2016, United States [30]

Randomized blinded crossover study

Country: Canada

Age: 18–50 y (28 ± 9 y)

Non-smoking adults without any risk for CV disease

n = 30 (17 female subjects)

PM2.5

PM2.5 targeted at 150 μg/m3for 2 h on 4 different occasions at least two weeks apart.

HDL antioxidant/ anti-inflammatory capacity measured as HDL oxidation index (HOI))

Paraoxonase (PON) activity

There was a trend towards bigger ΔHOI between PM2.5 and FA 1 h after exposures (p = 0.18) but not 20 h after. This trend became significant (p < 0.05) when baseline HOI was lower (< 1.5 or < 2.0), indicating decreased HDL antioxidant/anti-inflammatory capacity shortly after the exposures.

No significant differences in the enzymatic activity of PON-1 was observed.

Exposure to concentrated PM2.5 induced swift effects on HDL anti-oxidative/anti-inflammatory capacity. Changes were, however, transient and of short duration.

  1. Studies are shown in chronological order based on the year of publication