Study Shows Enzyme’s Role in Asthma
An enzyme that scientists recently found “kicks off” the chain of events leading to asthmatic symptoms may soon be a target for drug intervention.

To learn how the enzyme, arginase, worked in human asthma, scientists analyzed fluid and tissue samples from the lungs of asthmatic people and from nonasthmatic control subjects. No arginase was detected in the control samples, but significant amounts were found in the lungs of the people with asthma.

Since the research indicated that arginase played a crucial role in asthma attacks, lead researcher Marc E. Rothenberg, MD, PhD, of Cincinnati Children’s Hospital Medical Center said in a statement that scientists may now pursue developing antiasthma drugs that block the enzyme’s activity.

Previously, arginase was thought to be limited primarily to the liver, where it helps process the amino acid arginine.

“We’ve learned that arginase is involved in asthma regardless of the specific allergen used to induce the attack,” Rothenberg said.

The discovery of the role of arginase came as part of a National Institute of Allergy and Infectious Diseases-funded study in which scientists uncovered a cluster of 291 genes linked to asthma.

The researchers induced asthma in mice and then analyzed lung tissue with gene chips to see which genes were most active following the attacks.

The large number of genes involved in asthma—more than 6% of the mouse genome—came as some surprise, said lead authors Nives Zimmerman, MD, and Nina King, PhD. The findings were published in the June 15 Journal of Clinical Investigation.

RXS Reduce ED Trips
A new study shows that children with prescriptions for one or more asthma drugs visit the emergency department (ED) for lung disease less frequently than those who do not have prescriptions.

On May 6, World Asthma Day, University of Michigan pediatric researchers presented the results of their asthma study at the Pediatric Academic Societies annual meeting in Seattle. Conducted in 2001, the study analyzed more than 19,000 children in Michigan’s Medicaid program who had at least one inpatient, outpatient, or emergency visit for asthma in that year.

The researchers, led by Kevin J. Dombkowski, DrPH, also discovered that the regularity of some children’s asthma-related ED visits linked significantly to the patients’ race and location. Black children visited the ED more than twice as often as white children in the study, and urban children visited 42% more than nonurban children.

The authors conceded that it was not known whether the children with prescriptions actually used the drugs correctly or even if the prescriptions were filled. However, the researchers will expound on the study this summer by examining the relationships between medication use and ED visit rates.