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Mayo Clinic research in cardiovascular disease presented at Experimental Biology 2007

ROCHESTER, Minn. -- Mayo Clinic investigators will present and participate in 70 scientific presentations during the 2007 Experimental Biology meeting, April 28-May 2 in Washington, D.C.

This annual meeting brings together scientists from dozens of different disciplines whose work spans laboratory to translational to clinical research throughout the United States and the world. More than 12,000 biological and biomedical scientists are expected to attend.

The following summaries represent select Mayo presentations. Embargo times and dates vary per presentation.

MAYO RESEARCHERS IDENTIFY ANTIOXIDANT MECHANISMS INVOLVED IN PROTECTION AGAINST CARDIOVASCULAR DISEASE

EMBARGOED: 3 p.m. Eastern, April 29, 2007

Zvonimir Katusic, M.D., Ph.D., and Mayo colleagues have identified antioxidant mechanisms essential for regenerative function of endothelial progenitor cells (EPCs). EPCs move from the bone marrow into the bloodstream to repair the endothelium during a heart attack or stroke.

"This work paves the way for successful harnessing of the therapeutic effect of EPCs in the prevention and treatment of cardiovascular diseases," Dr. Katusic says.

The endothelium is a single layer of cells that line the inner surface of blood vessels. It protects tissues against the formation of blood clots in arteries and veins. If the endothelium is not working properly, patients are at risk for developing heart disease, stroke, peripheral vascular disease and venous thrombosis.

Normally, when EPCs move into the bloodstream, the body can restore cardiovascular functions that may have gone awry. EPCs are resistant to stress and are capable of repairing the endothelium even under conditions of extreme ischemia (inadequate supply of oxygen to an organ). But when EPCs are in insufficient supply, they are unable to protect the body from heart disease or stroke.

The antioxidant mechanism Dr. Katusic and colleagues identified includes enzymes that protect EPCs from oxidative stress in diseased arteries and veins. Oxidative stress is a consequence of the elevated production of free radicals that are associated with the inability of the antioxidant system to prevent free radicals from imposing tissue damage.

These research findings will lead to improved understanding of the molecular design of EPCs, says Dr. Katusic, a specialist in cardiovascular pharmacology at Mayo Clinic's campus in Rochester, Minn.

The study was funded by the National Heart Lung and Blood Institute.

EVIDENCE OF NANOPARTICLES FOUND IN PLAQUE-FILLED ARTERIES

EMBARGOED: 9:30 a.m. Eastern, April 30, 2007

Scientific evidence increasingly links arterial calcification to the presence of nanosized particles „o so small that some scientists question whether a nanoparticle can live and, if so, play a viable role in causing disease.

A new Mayo Clinic study cites evidence showing the presence of nanoparticles near plaque-filled arteries in animal models. The study suggests that nanoparticles potentially represent a previously unrecognized factor in the development of arteriosclerosis and calcific arterial disease.

Calcium deposits clog blood vessels and damage major organs, such as the heart. But the molecular mechanisms that kick-start this process, called pathologic calcification, haven¡¦t been explained.

The study's author, Maria Kraemer, a Mayo Graduate School student in Rochester, Minn., and colleagues isolated and propagated self-replicating, self-calcifying nanoparticles from human arteriosclerotic aneurysms and kidney stones.

"The work we are doing with human-derived nanoparticles is important because preliminary studies indicate that they may increase negative responses to arterial injury, possibly leading to blocked arteries and arterial calcification," Kraemer says.

Researchers tested their hypothesis by inoculating animal models with nanoparticles from human calcified tissues. A second group of models received a diluted inoculation. Blocked arteries were apparent in some animals in both groups 35 days after receiving the dosage.

This study was funded by Nanobac Pharmaceuticals, Inc., and Mayo Clinic.

Experimental Biology is an annual scientific meeting convened by the Federation of American Societies of Experimental Biology, including the American Association of Anatomists; American Physiological Society; American Society for Biochemistry and Molecular Biology; American Society for Investigative Pathology; American Society for Nutrition; and the American Society for Pharmacology and Experimental Therapeutics.

To obtain the latest news releases from Mayo Clinic, go to www.mayoclinic.org/news. MayoClinic.com (www.mayoclinic.com) is available as a resource for your health stories.

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