Experimental Woodsmoke Exposure During Exercise and Blood Oxidative Stress

Abstract

Blood oxidative stress occurred largely independent of PM2.5 concentrations. Future studies should employ longer duration smoke and exercise combined with physiologic parameters.

Controlled human exposures to wood smoke: a synthesis of the evidence

“…Abbreviations are denoted in the list of abbreviations in main text Ghio et al [ 16 ] Sehlstedt et al [ 20 ] Ferguson et al [ 22 ] Peters et al [ 24 ] Barregard et al [ 25 , 26 ] Danielsen et al [ 27 ] Murgia et al [ 28 ] Stockfelt et al [ 29 , 30 ] Forchhammer et al [ 32 ] Muala et al [ 35 ] Emissions Major PM class OC OC/Soot OC/Soot OC/Soot OC/Soot Soot/Ash Soot/Ash Exposure time 2 h 3 h 1.5 h 4 h 3 h 3 h 3 h Exercise (y/n) yes yes yes yes no no yes PM 2.5 conc. (μg/m 3 ) 485 224 low – 253.9 high – 506.2 243–279 SUP – 221 BOP – 148 low – 220.5 high – 352.38 314 Biomarkers Serum UA a ↓ at 1.5 h (combined) [ 24 ] Serum TEAC a ↑ at 1.5 h, 2.5 h (combined) [ 24 ] Serum oxidative damage markers 8-iso ↑ at 1.5 h (high and low) [ 24 ] LOOH ↓ at 2.5 h...…”

“…Although a slight decrease in forced expiratory volume in 1 s (FEV 1 ), forced vital capacity (FVC), and the ratio of these values (FEV 1 /FVC) was observed, none of these results reached significance. With regard to oxidative stress markers in the same study, Peters et al [24] reported that uric acid (UA) values decrease immediately post-exposure and plasma Trolox equivalent antioxidant capacity (TEAC) levels were increased both immediately after and 1 h after the exposure. A biomarker for plasma oxidative stress, lipid hydroperoxides (LOOHs), was decreased 1 h post-exposure, while 8-iso, 3-nitrotyrosine (3-NT) and plasma MPO increased immediately post WS-exposure.…”

“…Each endpoint was only assessed in 1-2 studies and there were many null findings and some inconsistencies. In some cases, findings within the same study were also inconsistent [24]. One of the most studied oxidative stress signals in general, 8-isoprostane in urine, was only assessed in two publications, which showed opposite results (although as mentioned previously, the decrease seen in Stockfelt et al [30] in likely due to in part and increase following the control exposure).…”

“…All time points are taken with 0 h = start of controlled exposure. Abbreviations are denoted in the list of abbreviations in main text Ghio et al [16] Sehlstedt et al [20] Ferguson et al [22] Peters et al [24] Barregard et al [25,26] Danielsen et al [27] Murgia et al [28] Stockfelt et al [29,30] [39,40] for more details study to show an increased recruitment of neutrophils in the lungs, the concentrations applied were in the high range (500 μg/m 3 ). Similar WS exposure conditions to those described in Ghio et al [16] were also used by Burbank et al [17] and Rebuli et al [18], although the latter did not include the exercise component.…”

“…Similarly, air-starved operation of a pellet stove [20] will also result in emissions dominated by organics, although soot and ash particles are also emitted. With increasing temperatures and air supply, soot aggregates will be formed, resulting in emission of a mixture of soot and organics from flaming combustion in stoves, fireplaces and open fires [21][22][23][24][25][26][27][28][29][30]. Upon even more complete combustion conditions (eg, highest temperatures in stoves with good air supply) soot is reduced to inorganic ash, consisting of elements that are refractory to combustion [31][32][33]38].…”