Aruni Bhatnagar, Ph.D., F.A.H.A.

Professor of Medicine; Director, Diabetes and Obesity Center, Distinguished University Scholar

Department of Medicine, Division of Cardiovascular Medicine, Diabetes and Obesity Center


502-852-5966 502-852-5724 aruni@louisville.edu

Education and Training:

Ph.D.: Kanpur University, India
Fellowship: University of Texas Medical Branch at Galveston

Research:

Director: The Diabetes and Obesity Center

Research Interests:

The major focus of our research is to elucidate the mechanisms by which oxidative stress affects cardiovascular function. In particular, we are interested in the role of lipid peroxidation as a contributor to myocardial ischemic injury and atherosclerosis. Although lipid peroxidation generates several reactive intermediates and end products, lipid-derived unsaturated aldehydes are believed to be a major source of oxidative stress and these toxicants appear to be critical mediators of tissue injury due to lipid peroxidation. In order to understand how the cardiovascular tissues protect themselves from the toxic products of lipid peroxidation, we are currently investigating the biochemical mechanisms by which unsaturated aldehydes are detoxified in the heart and blood vessels. We have learned that the enzymes - aldose reductase, glutathione S-transferases and aldehyde dehydrogenase are the major constituents of aldehyde metabolism in the heart, and vascular smooth muscle and endothelial cells, and that these enzymes function in tandem to protect cardiovascular tissues from the harmful effects of lipid peroxidation. Based on this understanding we are currently assessing in detail the role of aldose reductase and related aldo-keto reductases in the detoxification of lipid peroxidation products. We are investigating whether inhibition or upregulation of these enzymes affects the ability of the heart to withstand oxidative stress during ischemia and reperfusion. In a parallel series of experiments we are studying the role of aldose reductase in atherogenesis in an effort to ascertain whether changes in aldehyde metabolism alter plaque burden in atherosclerotic animals. We believe that this line of inquiry will lead to a better understanding of the mechanisms by which oxidative stress mediates or exacerbates cardiovascular disease, and how the untoward cardiovascular effects of lipid peroxidation could be prevented.

In addition to the metabolism and detoxification of endogenous aldehydes, our research interests also include cardiovascular toxicity of environmental aldehydes. Several ubiquitous pollutants such as gasoline vapor, car exhaust, smoke, and smog contain significant amounts of reactive aldehydes. Similar aldehydes are also generated during the metabolism of pollutants such as butadiene, vinyl chloride and allylamine and cardiotoxic drugs such as cylcophosphamide and adriamycin. These aldehydes are related, in structure and toxicity, to those generated endogenously during lipid peoxidation. Thus, our work on the lipid peroxidation-derived aldehydes bears significance for understanding the cardiovascular effects of environmental aldehydes. To examine this rigorously, we have recently initiated a series of studies to test whether environmental exposure to aldehydes exacerbates atherosclerosis and induces myocardial dysfunction, and whether aldehyde exposure is a risk factor for the development of heart disease.

Selected Publications: