Antioxidant in Vegetables Helps Cystic Fibrosis, Inflammation Disorders

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An antioxidant called thiocyanate, which is found in vegetables such as broccoli and cauliflower, protects against cell damage caused by chemicals produced by the body in response to infection and injury. This finding may help in inflammation disorders, including cystic fibrosis, heart disease, and diabetes.

A research team led by Zhe Lu, MD, PhD, professor of physiology at the University of Pennsylvania School of Medicine, has shown that thiocyanate, which the body produces naturally, protects the cells in the lungs from damage caused by the accumulation of hydrogen peroxide and hypochlorite, which the body also produces when it experiences infection or injury. The scientists have also found that thiocyanate protects cells from hypochlorite produced in reactions that involve an enzyme called MPO, which is released from white blood cells during the inflammatory process.

These findings are important for understanding the genetic defect involved in cystic fibrosis, according to Bert Shapiro, PhD, at the National Institutes of Health’s National Institute of General Medical Sciences. He noted that the work of the investigators suggests “that the lungs of people with the disease are more susceptible to the damaging effects of cellular oxidants.”

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Dr. Lu’s team also looked at three other inflammation-related conditions—diabetes, neurodegeneration, and cardiovascular disease—and found that thiocyanate at blood concentrations of 100 micromolar (micromoles per liter) or greater significantly reduced the negative impact of MPO in cells, including those that line the blood vessels. The blood levels of thiocyanate in the general population vary from 10 to 140 micromolar. The findings of the team suggest that people with an inadequate level of thiocyanate may be at risk for additional cell damage caused by the hypochlorite produced during inflammation, which in turn would exacerbate inflammatory diseases and predispose individuals to diseases associated to MPO activity, such as atherosclerosis.

Cystic fibrosis is characterized by exaggerated inflammation in the lungs and the digestive system. Lung damage caused by the inflammation and recurring infections cause about 90 percent of symptoms and deaths in patients with the disease. Cystic fibrosis is caused by mutations in a specific protein (CF transmembrane conductance regulator, or CFTR), which transports chloride ions and thiocyanate ions. These latter ions may limit the accumulation of hydrogen peroxide and hypochlorite.

Diabetes is also common among people who have cystic fibrosis, and diabetes is associated with higher levels of MPO. The researchers found that thiocyanate greatly reduced the damaged caused by MPO to pancreas and endothelial cells (which line the blood vessels). They conclude that MPO, without the presence of adequate thiocyanate, may contribute to diabetes and also aggravate MPO-produced damage in patients who have inflammatory diseases.

Administering thiocyanate directly to the respiratory and digestive systems in people who have cystic fibrosis could be a therapeutic approach, note the researchers. Among the general public, people who have low levels of thiocyanate may be at risk for inflammation or inflammation-related diseases. Given their findings, Dr. Lu noted that “my colleagues and I will vigorously investigate the potential health benefit of thiocyanate, although at this time, he emphasized that until more is known about the impact of thiocyanate on human health, “it would be unwise for anyone to self-administer thiocyanate.”

SOURCE:
University of Pennsylvania School of Medicine, press release Nov. 16, 2009

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