TUESDAY, March 4, 2003 (HealthDayNews) -- A new kind of treatment for sickle cell disease -- having children breathe nitric oxide for hours -- eases the pain of the vein-blocking crises suffered by patients with the condition, researchers report.
The nitric oxide treatment strikes at the cause of those crises, while current treatments aim only at relieving symptoms, says Dr. Debra L. Weiner, assistant in emergency medicine at Children's Hospital Boston. She is the leader of the group reporting the findings in the March 5 issue of the Journal of the American Medical Association. And while it is a small study, involving only 20 children, "the results are encouraging and warrant further investigation," she says.
Sickle cell disease is a genetic condition occurring primarily among people of African descent; it affects one of every 500 black newborns. The genetic defect causes production of abnormal molecules of hemoglobin, the oxygen-carrying protein in red blood cells. Those molecules clump together, giving red cells the distinctive appearance described by the condition's name. Patients suffer painful episodes of blood vessel blockage that can start in infancy, become more common with age and cause severe damage to many organs.
The new treatment is based on the recently acquired knowledge that those episodes can be precipitated by a lack of nitric oxide, which acts to keep blood vessels open, Weiner says.
"Research at the National Institutes of Health indicates that the abnormal hemoglobin scavenges nitric oxide and makes it unavailable," she says. The result is periodic crises and increasing inflammation.
The study had 10 children with severe blood vessel crises breathe nitric oxide through face masks for up to four hours, while 10 children with similar crises breathed air through their masks. As the children reported their pain hour by hour, the reduction in pain for those breathing nitric oxide became statistically significant after three hours. The nitric oxide group used less morphine and tended to get out of the hospital faster. There was no evidence the nitric oxide treatment was unsafe.
The obvious next step is a larger study with more patients breathing nitric oxide for a longer period, Weiner says. The details of that study are still being worked out. There is an indication that longer treatment will not only reduce pain more but also reduce organ-damaging inflammation, she says.
The Harvard study is one example of how nitric oxide research has excited people in the field, says Dr. Ronald L. Nagel, a professor of medicine at Albert Einstein School of Medicine and co-director, with Dr. Mary E. Fader, of the sickle cell unit at Montefiore Hospital in the Bronx.
"While the numbers are small and the p value [of statistical significance] is small, this is part of a new approach that a number of people are studying,"" Nagel says.
His group is proposing a trial of a different kind of treatment centered on nitric oxide. It would give patients arginine, an amino acid that induces nitric oxide production.
The newly reported study, Nagel says, "will stimulate people in the field to consider nitric oxide as a treatment for sickle cell disease."
More information
You can learn about sickle cell disease, its genetics and its treatment from the National Institute of Medicine or the Sickle Cell Disease Association of America.
