Gas therapy for sickle-cell anemia.
Sickle-cell anemia is caused by an abnormal form of hemoglobin, an oxygen-carrying molecule in the blood. The defective hemoglobin molecules stick together after releasing oxygen and form sickle shapes that clog the body's tiny blood vessels. Such jams cause a painful, potentially life-threatening sickle-cell crisis.
A 1977 report had suggested that nitric oxide alters the shape of hemoglobin. Head, Ricardo Martinez-Ruiz, and their colleagues wondered if this gas might help people afflicted with sickle-cell anemia.
The researchers recruited nine people with the disease who were not having a sickle-cell crisis. They had the volunteers inhale a low dose of nitric oxide for 45 minutes. In eight of the volunteers, the experimental treatment increased hemoglobin's affinity for oxygen and thus prevented the molecule from assuming the abnormal shape. Other studies have suggested that such an effect would decrease the likelihood of a sickle-cell crisis. The inhalation of nitric oxide had no effect on hemoglobin in the blood of volunteers without sickle-cell disease. The researchers report their findings in the September Journal of Clinical Investigation.
Head and his colleagues are now beginning to examine whether the gas may help reverse a sickle-cell crisis. They are recruiting 60 volunteers for a study expected to yield results in a year.
"Right now, there is no therapy for [sickle-cell] crisis," Head says, noting that patients generally receive only pain killers and other palliative treatments when they suffer an attack.
Head suspects that nitric oxide, used on a regular basis, would ward off such episodes. He imagines patients someday using a gas inhaler much like an asthma inhaler to prevent their hemoglobin from getting into a traffic jam.
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|Title Annotation:||inhalation of nitric oxide gas|
|Article Type:||Brief Article|
|Date:||Sep 20, 1997|
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