Related Experiment Videos
Particulate matter exposure impairs systemic microvascular endothelium-dependent dilation.
Timothy R Nurkiewicz1, Dale W Porter, Mark Barger
1Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia 26506-9229, USA. tnurkiewicz@hsc.wvu.edu
Environmental Health Perspectives
|September 4, 2004
Summary
Pulmonary exposure to residual oil fly ash (ROFA), a particulate matter (PM) surrogate, impairs systemic blood vessel dilation. This occurs even without significant lung inflammation, indicating PM affects microvascular function directly.
Area of Science:
- Environmental Health Sciences
- Cardiovascular Physiology
- Toxicology
Background:
- Acute exposure to airborne particulate matter (PM) is linked to cardiovascular dysfunction.
- The precise mechanisms by which PM causes systemic effects are not fully understood.
- Investigating PM surrogates like residual oil fly ash (ROFA) can elucidate these pathways.
Purpose of the Study:
- To determine if pulmonary exposure to ROFA affects endothelium-dependent dilation in the systemic microcirculation.
- To assess if PM exposure impacts microvascular function independently of pulmonary inflammation.
Main Methods:
- Rats were intratracheally instilled with varying doses of ROFA or control substances (saline, TiO2).
- In vivo microscopy examined systemic arteriolar dilator responses to a Ca2+ ionophore (A23187).
- Bronchoalveolar lavage (BAL) analyzed pulmonary inflammation and damage markers.
- Nitric oxide (NO) sensitivity was tested using iontophoretically applied sodium nitroprusside.
Main Results:
- ROFA exposure significantly attenuated A23187-induced arteriolar dilation, indicating impaired endothelium-dependent function.
- Pulmonary inflammation and damage were observed at higher ROFA doses (1-2 mg), but not with TiO2 or lower ROFA doses.
- Arteriolar smooth muscle sensitivity to NO remained unchanged, suggesting the effect was on the endothelium.
- Increased venular leukocyte adhesion and rolling indicated local systemic microvascular inflammation.
Conclusions:
- Pulmonary exposure to PM, exemplified by ROFA, impairs systemic endothelium-dependent arteriolar dilation.
- PM exposure can negatively affect systemic microvascular function even without detectable pulmonary inflammation.
- These findings highlight a direct link between inhaled pollutants and systemic cardiovascular impairment.