Effects of diesel exhaust inhalation on heart rate variability in human volunteers

Abstract

Objectives-Particulate matter (PM) air pollution is associated with alterations in cardiac conductance and sudden cardiac death in epidemiological studies. Traffic-related air pollutants, including diesel exhaust (DE) may be at least partly responsible for these effects. In this experimental study we assessed whether short-term exposure to DE would result in alterations in heart rate variability (HRV), a non-invasive measure of autonomic control of the heart.Methods-In a double-blind, crossover, controlled-exposure study, 16 adult volunteers were exposed (at rest) in randomized order to filtered air (FA) and two levels of diluted DE (100 or 200 μg/m 3 of fine particulate matter) in two-hour sessions. Before, and at four time-points after each exposure we assessed HRV. HRV parameters assessed included both time domain statistics (standard deviation of N-N intervals (SDNN), and the square root of the mean of the sum of squared differences between successive N-N intervals (RMSSD)) and frequency domain statistics (high frequency power (HF), low frequency power (LF), and the LF/HF ratio).Results-We observed an effect at 3-hours after initiation of DE inhalation on the frequency domain statistics of HRV. DE at 200 μg/m 3 elicited an increase in HF power compared to FA (Δ=0.33; 95% CI: 0.01 to 0.7) and a decrease in LF/HF ratio (Δ=-0.74; 95% CI: -1.2 to -0.2). The effect of DE on HF power was not consistent among study participants. There was no DE-effect on time domain statistics and no significant DE effect on HRV in later time-points.Conclusions-We did not observe a consistent DE effect on the autonomic control of the heart in a controlled exposure experiment in young participants. Efforts are warranted to understand discrepancies between epidemiological and experimental studies of air pollution's impact on HRV.

Oxidative Stress, Inflammatory Biomarkers, and Toxicity in Mouse Lung and Liver after Inhalation Exposure to 100% Biodiesel or Petroleum Diesel Emissions

“…Reductions in pulmonary function have also been reported following occupational exposures in chronic studies (Rudell et al, 1996). In addition, diesel PM has been associated with changes in heart rate, increased incidence of arrhythmias, impairment of vasodilation, increase in blood pressure, and systemic inflammation (Hazari et al, 2011;Peretz et al, 2008;Tornqvist et al, 2007;Nemmar et al, 2007;Carll et al, 2013;Harkema et al, 2009;Knuckles et al, 2011). Human studies by Mills et al (2005Mills et al ( , 2007aMills et al ( , 2007b) demonstrated a dose-dependent increase in prothrombotic effects and acute myocardial ischemia upon exposure to diesel exhaust.…”

Particulate Matter Air Pollution and Cardiovascular Disease

“…Some studies have reported increases in HRV mediated by PM, specifically among younger healthy people and patients with chronic obstructive lung disease. 156,208,216 Nevertheless, the general pattern suggests that PM exposure is associated with increased heart rate and reductions in most indices of HRV among older or susceptible individuals, such as those with obesity and the metabolic syndrome. Typically, timedomain measures (eg, standard deviation of normal RR intervals) and total power are reduced within hours after exposure.…”

“…No differences were reported in HRV with fine-PM exposures. Although some controlled-exposure studies have reported either no acute changes 390 or, on occasion, increases in HRV metrics in subsets of individuals, 208,393,401 these studies generally demonstrate that acute PM exposure is capable of reducing HRV. More consistent reductions have been found among older adults (compared with younger subjects or those with lung diseases, who show mixed responses) and perhaps with exposures to larger particles.…”

Toxicidade cardiovascular e inflamatória aguda induzida pela inalação de partículas dos combustíveis diesel e biodiesel

“…Estudos recentes demonstraram que através da instilação intratraqueal aguda do PM 2,5 em ratos Wistar, na dose de 100 µg/mL e 500 µg/mL (Rivero et al, 2005a) e na dose de 50 µg/mL (Maatz et al, 2009) Em contrapartida, a literatura apresenta inúmeros estudos experimentais de toxicidade da queima do diesel (Campen et al, 2005;Anselme et al, 2007;Gottipolu et al, 2009;Saxena et al, 2009;Sunil et al, 2009) e de exposição controlada em humanos Lucking et al, 2008;Peretz et al, 2008aPeretz et al, , 2008bLangrish et al, 2009 Lucking et al, 2008;Langrish et al, 2009), a reatividade vascular (Peretz et al, 2008a) e a VFC (Peretz et al, 2008b). O compostos orgânicos da queima do diesel, são descritos como geradores de inflamação e estresse oxidativo (Ball et al, 2000;Saldiva et al, 2002;Nemmar et al, 2009;Sunil et al, 2009 Outros estudos também demonstraram que o B100 reduz as emissões de MP, CO e HC e aumenta as emissões de NO X (parâmetro não avaliado neste estudo) (EPA, 2002a;Graboski et al, 2003;Zou et al, 2003;Yuan et al, 2007;Lapuerta et al, 2008a).…”