Cardiovascular and Thermoregulatory Effects of Inhaled PM-Associated Transition Metals: A Potential Interaction between Nickel and Vanadium Sulfate

Abstract

Recent epidemiological studies have shown an association between daily morbidity and mortality and ambient particulate matter (PM) air pollution. It has been proposed that bioavailable metal constituents of PM are responsible for many of the reported adverse health effects. Studies of instilled residual oil fly ash (ROFA) demonstrated immediate and delayed responses, consisting of bradycardia, hypothermia, and arrhythmogenesis in conscious, unrestrained rats. Further investigation of instilled ROFA-associated transition metals showed that vanadium (V) induced the immediate responses, while nickel (Ni) was responsible for the delayed effects. Furthermore, Ni potentiated the immediate effects caused by V when administered concomitantly. The present study examined the responses to these metals in a whole-body inhalation exposure. To ensure valid dosimetric comparisons with instillation studies, 4 target exposure concentrations ranging from 0.3-2.4 mg/m(3) were used to incorporate estimates of total inhalation dose derived using different ventilatory parameters. Rats were implanted with radiotelemetry transmitters to continuously acquire heart rate (HR), core temperature (T(CO)), and electrocardiographic data throughout the exposure. Animals were exposed to aerosolized Ni, V, or Ni + V for 6 h per day x 4 days, after which serum and bronchoalveolar lavage samples were taken. Even at the highest concentration, V failed to induce any significant change in HR or T(CO). Ni caused delayed bradycardia, hypothermia, and arrhythmogenesis at concentrations > 1.2 mg/m(3). When combined, Ni and V produced observable delayed effects at 0.5 mg/m(3) and potentiated responses at 1.3 mg/m(3), greater than were produced by the highest concentration of Ni (2.1 mg/m(3)) alone. These results indicate a possible synergistic relationship between inhaled Ni and V, and provide insight into potential interactions regarding the toxicity of PM-associated metals.

Association between short term exposure to fine particulate matter and heart rate variability in older subjects with and without heart disease

“…27 28 Furthermore, studies of hospital admissions for respiratory and cardiac diseases in eastern Canada suggest that PM with high sulfate composition has more deleterious cardiovascular effects than low sulfate PM 2.5 . 29 Moreover, in vitro and in vivo studies of PM stripped of the metal content found attenuation of both pulmonary and vascular inflammation 30 and arrhythmogenic potential of PM 2.5 . 31 32 Finally, a single study in healthy aluminium workers 33 suggests that the metal composition of PM influences cardiac autonomic function, measured by HRV.…”

Microbial Stimulation by Mycoplasma fermentans Synergistically Amplifies IL-6 Release by Human Lung Fibroblasts in Response to Residual Oil Fly Ash (ROFA) and Nickel

“…Using data from the Six Cities studies, Laden et al (2000) demonstrated that Ni was positively associated with daily deaths. In animal studies, Ni synergistically interacts with V to initiate untoward cardiovascular effects following inhalational exposure (Campen et al, 2001).…”

Efeitos cardiopulmonares da exposição ao material particulado fino (MP2,5) proveniente do concentrador de partículas ambientais (CPA) na hipertrofia ventricular esquerda de ratos wistar

“…Estas diferenças podem portando significar que não há necessariamente uma similaridade nos desfechos, e que o valor prognóstico da VFC que é demonstrado em diversas patologias humanas, ainda é prematuro para uso em roedores como um indicador de prognostico negativo ou toxicidade após exposições a poluentes ambientais (Rowan III et al, 2007). Conforme apontado por Kodavanti et al (2003) os estudos experimentais que avaliam os efeitos da exposição ao MP de origem veicular baseiam se principalmente em achados fisiológicos, muito pouco se avaliou quanto a histopatologia e bioquímica do tecido cardíaco e além disso há uma grande variabilidade quanto aos métodos e duração da exposição, composição do MP utilizado e espaço de tempo entre as exposições e avaliação dos desfechos (Vincent et al, 1997;Watkinson et al, 1998;Campen et al, 2001;Wellenius et al, 2002) dificultando comparações.…”