Dietary Antioxidants Protects Cells

Scientists at the University of Pennsylvania School of Medicine discovered

that a dietary antioxidant found in such vegetables as broccoli and cauliflower protects cells from damage caused by chemicals generated during the body's inflammatory response to infection and injury. The finding has implications for such inflammation-based disorders as cystic fibrosis (CF), diabetes, heart disease, and neurodegeneration

Through cell-culture studies and a synthesis of known antioxidant biochemistry, Zhe Lu, MD, PhD , Professor of Physiology, Yanping Xu , MD, PhD , Seni or Research Investigator, and Szilvia Sz=E9p , PhD, postdoctoral researcher showed that the antioxidant thiocyanate normally existing in the body protects lung cells from injuries caused by accumulations of hydrogen peroxide=

and hypochlorite, the active ingredient in household bleach. These potentially harmful chemicals are made by the body as a reaction to infection and =

injury. In addition, thiocyanate also protects cells from hypochlorite produced in reactions involving MPO, an enzyme released from germ-fighting whit=

e blood cells during inflammation. They published their finding this week in the Proceedings of the National Academy of Sciences. Lu is also an Investigator of the Howard Hughes Medical Institute.=20

"Dr. Lu's work throws new light on how the genetic defect underlying CF leads to the lung illnesses that are the leading cause of death," said Bert Shapiro, Ph.D., who oversees membrane structure grants at the National Institutes of Health's National Institute of General Medical Sciences (NIGMS). "H=

is team's findings suggest that the lungs of people with the disease are more susceptible to the damaging effects of cellular oxidants. While the idea=

is tantalizing and creative, further testing is needed to confirm it."=20

The research team demonstrated that in three additional cell types used to =

extend their ideas to other inflammation-related conditions - cardiovascular disease, neurodegeneration, and diabetes - thiocyanate at blood concentrations of at least 100 micromolar (micromoles per liter) greatly reduces the=

toxicity of MPO in cells, including those lining blood vessels. Humans naturally derive thiocyanate from some vegetables and blood levels of thiocyanate in the general population vary from 10 to 140 micromolar.

This comparison raises the possibility, the authors point out, that without=

an adequate dietary supply of thiocyanate, hypochlorite produced by the body during inflammation would cause additional collateral damage to cells, thus worsening inflammatory diseases, and predisposing humans to diseases linked to MPO activity, including atherosclerosis.=20


Xu Y, SzE9p S, Lu Z.

The antioxidant role of thiocyanate in the pathogenesis of cystic fibrosis =

and other inflammation-related diseases.

Proc Natl Acad Sci U S A. 2009 Nov 16.=20

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