Treatment may attack sickle cell cause Researchers say food additive has promise in blood disorder fight

January 14, 1993|By New York Times News Service

WASHINGTON -- Preliminary tests suggest that a potential treatment for sickle cell disease and related blood disorders could attack the underlying cause of the illnesses for the first time, say researchers.

In a small group of patients, they said yesterday, treatment with a naturally occurring chemical stimulated production of a kind of hemoglobin in the blood that is known to benefit people with sickle cell disease or beta thalassemia, which are related inherited anemias.

But they said longer studies with more patients were needed to see whether the treatment produced the expected clinical benefit.

Hemoglobin is the protein in red blood cells that carries oxygen through the bloodstream. With sickle cell and beta thalassemia, genetic defects result in the production of abnormal hemoglobin that can lead to dangerous and even lethal symptoms.

In a pilot study involving six patients, intravenous infusion of butyrate, a simple fatty acid that is found in the body and in certain foods, resulted in a rapid increase in fetal hemoglobin, a type common early in life, the scientists report in today's issue of the New England Journal of Medicine.

The chemical, which is also a food additive, stimulates a dormant gene responsible for producing fetal hemoglobin, causing a sharp increase in the ratio of fetal hemoglobin to the defective adult variety, said Dr. Susan Perrine of Children's Hospital Oakland Research Institute in Oakland, Calif.

"This is an early trial and we don't want to raise the hopes of patients too soon," said Dr. Perrine, the study's lead scientist, "but I think this has potential to become a definitive treatment of the underlying disease, as opposed to today's palliative treatment of symptoms to support the patient after complications arise."

Sickle cell disease is an incurable condition characterized by an abnormal form of hemoglobin that causes red blood cells to stiffen, distort into odd shapes and clog blood vessels. These blockages not only lead to pain, but can also damage internal organs and cause other problems.

In the United States, the disease primarily affects blacks, but variations are seen in people of Mediterranean, Middle Eastern and East Indian descent. An estimated 60,000 to 80,000 American blacks have sickle cell disease. One in 12 blacks carry the genetic trait for the disease.

With beta thalassemia, which afflicts 5,000 to 10,000 Americans as well as millions of people in other parts of the world, the body's bone marrow produces large quantities of red blood cells that die almost immediately, leaving the patient extremely anemic.

Sickle cell experts said the potential treatment, and another that also affects fetal hemoglobin that appears in a related paper in the journal, may mark the beginning of a new therapeutic era for these diseases. Until now, doctors have only been able to treat the life-threatening symptoms of the diseases.

Dr. Clarice Reid, chief of the sickle cell branch at the National Heart, Lung and Blood Institute, said clinical studies with chemicals that increase fetal hemoglobin were in an early stage but pointed to "exciting potential therapies."

"Patients with high levels of fetal hemoglobin, in general, have fewer symptoms," Dr. Reid said, "and these drugs, while not a cure, offer hope."

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