Uptake and Inflammatory Effects of Nanoparticles in a Human Vascular Endothelial Cell Line

EPA Grant Number: R832347C136
Subproject: this is subproject number 136 , established and managed by the Center Director under grant R832347
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Health Effects Institute (2005 — 2010)
Center Director: Greenbaum, Daniel S.
Title: Uptake and Inflammatory Effects of Nanoparticles in a Human Vascular Endothelial Cell Line
Investigators: Kennedy, Ian M.
Institution: Health Effects Institute , Desert Research Institue , Michigan State University , University of California–Davis , University of Medicine and Dentistry of New Jersey
EPA Project Officer: Hunt, Sherri
Project Period: August 30, 2005 through August 29, 2010
RFA: Health Effects Institute (2010) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

Epidemiologic and toxicologic studies indicate that ambient particulate matter (PM) — a complex mixture of solid and liquid particles suspended in air — has multiple effects on health. One of the key issues in assessing the health effects of PM is determining the physical characteristics (such as size and charge) and chemical characteristics most responsible for toxicity. Particles # 10 μm in aerodynamic diameter (PM10) are of most concern because these particles are respirable by humans. To protect the general population and groups considered most vulnerable to adverse effects from PM in the United States, the Environmental Protection Agency monitors PM10 levels and has promulgated National Ambient Air Quality Standards for particles # 2.5 μm in aerodynamic diameter (PM2.5, or fine particles). Some scientists believe that particles < 100 nm in diameter may be particularly toxic. These particles are referred to as ultrafine (< 100 nm in all dimensions) or nanoparticles (with at least one dimension < 100 nm). Several studies have suggested that metals may be important toxic components of the PM mixture.

A further key issue is the identification of pathways by which particles interact with cells in the airways and other cells to exert toxic effects. Some studies suggest that after inhalation small particles move rapidly out of the lung, enter the bloodstream, and affect other tissues. Because endothelial cells — a layer of specialized cells that line the interior of blood vessels — serve as a barrier between tissues and the bloodstream, the passage of inhaled particles from lungs into the circulation and then into tissue implies that particles have the opportunity to interact with the endothelial layer. Because responses of endothelial cells also play a critical role in the development of atherosclerosis, and because exposure to particles has been reported to affect the development of atherosclerosis, understanding the response of endothelial cells to particles may be important.

In response to HEI’s Request for Preliminary Applications RFPA 04-6, Dr. Ian Kennedy and colleagues at the University of California–Davis, proposed to generate nanoparticles of the oxides of four different metals — iron, zinc, yttrium, and cerium. They chose these metals because iron and zinc are abundant in urban and diesel exhaust PM, iron and cerium are components of recently developed automobile technologies, and yttrium can be “tagged” with a fluorescent marker to identify the localization of particles taken up into cells. The investigators also proposed to evaluate the size and composition of the particles, and to study their potential to induce inflammatory effects in human aortic endothelial cells (HAECs). The investigators also proposed to identify where inside the HAECs the particles would be found after co-culture with the cells. The investigators hypothesized that the biologic effects of the particles would differ depending on their chemical composition and physical properties. The Health Research Committee recommended the study for one year of funding, to determine whether the proposed approaches would be successful.

Approach:

Dr. Kennedy and colleagues will use a flame combustion system to generate nanoparticles of the oxides of iron, zinc, yttrium, and cerium. They will characterize several physical properties of the particles, using inductively coupled plasma–mass spectrometry, X-ray diffraction, transmission electron microscopy (TEM), and a scanning mobility particle sizer. They also will calculate the particles’ surface area.

The investigators will incubate particles in solution in a range of concentrations with an HAEC line in vitro, for 4 hours in most experiments. The HAECs will be evaluated for the induction of reactive oxygen species (ROS) and markers of oxidative stress and inflammation. Because their attempt to use a fluorescent tagging approach to identify particles within HAECs was not successful, the investigators used TEM on HAECs to identify the subcellular localization of the particles. Responses to cerium oxide particles were evaluated in only a few experiments.


Main Center Abstract and Reports:

R832347    Health Effects Institute (2005 — 2010)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R832347C135 Mechanisms of Particulate Matter Toxicity in Neonatal and Young Adult Rat Lungs
R832347C136 Uptake and Inflammatory Effects of Nanoparticles in a Human Vascular Endothelial Cell Line
R832347C138 Health Effects of Real-World Exposure to Diesel Exhaust in Persons with Asthma
R832347C140 Extended Follow-Up and Spatial Analysis of the American Cancer Society Study Linking Particulate Air Pollution and Mortality
R832347C141 Air Pollution Effects on Ventricular Repolarization
R832347C143 Measurement and Modeling of Exposure to Selected Air Toxics for Health Effects Studies and Verification by Biomarkers
R832347C144 Genotoxicity of 1,3-Butadiene and Its Epoxy Intermediates
R832347C145 Effects of Concentrated Ambient Particles and Diesel Emissions on Rat Airways
R832347C147 Atmospheric Transformation of Diesel Emissions