Bernd Lab Research Questions

Background

Alveolae

Air enters the body through the mouth or the nose and travels down the trachea, or windpipe. It then travels into either the left or right bronchus. The two bronchi branch off into smaller tubes called bronchioles. The bronchioles allow for air to be carried deeper into the lungs. The exchange of oxygen and carbon dioxide into and out of the bloodstream take place within the alveolae,tiny air sacs inside the lung. This also means thatthese epithelial cells provide protection against any pollutants you breathe in. Many of these pollutants trigger an immune response and cause cellular damage due to oxidation ('stealing an electron from a molecule'). One of the most well-known oxidizing pollutants is ozone.

Ozone

Over the past four decades, many researchers have attempted to understand the underlying causes between ambient ozone levels and pulmonary distress to provide a scientific basis for the Environmental Protection Agency’s standard for permissible levels of ambient ozone (Balmes 1993). Several studies have shown that chronic airway diseases – such as asthma, lung cancers, and acute respiratory distress syndrome (ARDS) – may be associated with oxidative stressors, such as exposure to ozone (Chen et al. 2007; Balmes 1993; TenHoor et al. 2001; Urata 2006). As a result of these and other studies, the EPA has identified counties across the country that do not meet the current air quality standards (an average of .08 parts per million over 8 hours) and has designed strategic plans on how to amend these failings (Smith 2004).

Ozone is a highly reactive oxidative species normally found in the stratosphere (Wang et al. 2006; Atmospheric Chemistry). Typically, ozone is formed in the stratosphere when ultraviolet photons photolyze oxygen into ozone. Ozone is then able to absorb ultraviolet photons from the sun (Atmospheric Chemistry). In the stratosphere, ozone is immensely important to the earth: it protects life from the deleterious effects of the sun by absorbing a majority of the sun’s ultra violet rays. However, tropospheric ozone, largely a product of incomplete combustion of carbon-based fuels, can be damaging to life due to the formation of reactive oxygen species (Sadava et al. 2008).

Reactive Oxygen Species

Ozone is an example of a reactive oxygen species (ROS)but it is not the only kind and ROS's can't be lumped together as being 'bad'. Some ROS are important mediators of intracellular signaling cascades required for normal cellular function (Nordberg and Arner, 2001). However, excessive levels of ROS can lead to oxidative stress and cellular damage. Therefore, the redox state, orbalance between oxidants and antioxidants, is crucial for proper cell function (Nordberg and Arner, 2001). Everything in moderation!

Other groups have initiated whole animal studies to look at the effect of O3 on rat lung cells. This lab is using a cell culture system. Our studies focus on environmentally relevant O3 exposure levels and analyze effects on cell proliferation, cell death and glutathione (GSH) levels (GSH is an important antioxidant and indicator of the redox state of the cell)

In addition, we are interested in the combined effects of O3 and other oxidizing factors including metabolic rate, estrogen levels and alcohol consumption (all in a cell culture system) See links at the top of the page for more information about these topics

Health Risks

Patients with certain medical conditions such as sepsis, asthma, or emphysema have an increased risk of developing complications from ozone exposure. For example, asthma patients may experience an increased frequency of asthma attacks, resulting in an increased use of health care services (EPA, 2007). Therefore ozone exposure can lead to financial concern for both patients and local facilities. In areas where proper medical care is scarce, these complications could prove fatal.

References

Balmes, J. R. (1993). The role of ozone exposure in the epidemiology of asthma. Environmental Health Perspectives Supplements, 101(4), 219-224.

Chen, C., Arjomandi, M., Balmes, J., Tager, I., & Holland, N. (2007). Effects of chronic and acute ozone exposure on lipid peroxidation and antioxidant capacity in healthy young adults. Environmental Health Perspectives, 115(12), 1732-1737.

Environmental Protection Agency. “Health Effects of Ozone in Patients with Asthma.” Ozone and Your Patient’s Health. October 2007. <http://www.epa.gov/03healthtraining/effects.html>.

Norberg, J. and E.S. Arner. “Reactive oxygen species, antioxidants, and the mammalian thioredoxin system.” Free Radical Biology and Medicine. 31.11 (Dec. 2001): 1287-1312.

Sadava, D., Heller, H. C., Orians, G. H., Purves, W. K., & Hillis, D. M. (2007). Life: The science of biology (8th edition ed.). USA: The Courier Companies, Inc.

TenHoor, T., Mannino, D. M., & Moss, M. (2001). Risk factors for ARDS in the united states - analysis of the 1993 national mortality followback study Chest, 119, 1179-1184.

Urata, Y., Ihara, Y., Murata, H., Goto, S., Koji, T., Yodoi, J., et al. (2006). 17 ß-estradiol protects against oxidative stress-induced cell death through the Glutathione/Glutaredoxin-dependent redox regulation of akt in myocardiac H9c2 cells. The Journal of Biological Chemistry, 281(19), 13092-13102.

Wang, J., Wang, S., Manzer, R., McConville, G., & Mason, R. J. (2006). Ozone induces oxidative stress in rat alveolar type II and type I-like cells. Free Radical Biology and Medicine, 40, 1914-1928.