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Reversing anemia

Red blood cells under the electron microscope: premature death in thalassemia

CDC / JANICE HANEY CARRRed blood cells under the electron microscope: premature death in thalassemiaCDC / JANICE HANEY CARR

In tests with an experimental drug, an international team coordinated by Brazilian biologist Ivan Cruz Moura and French physician Olivier Hermine showed that it is possible to control and even reverse the most common and debilitating symptom of thalassemia, an incurable genetic disease that requires lifetime blood transfusions. Thalassemia is caused by defects in the genes that code one of the two proteins in hemoglobin, the molecule that carries oxygen and carbon dioxide through the bloodstream. These genetic alterations lead to production of defective hemoglobin molecules and early death of the red blood cells that contain them. The premature death of these cells causes anemia, a significant reduction in the number of circulating red blood cells, which can affect a person’s development and lead to heart disease. Through experiments on rodents and early tests on human thalassemia patients, the researchers discovered that the maturation rate of red blood cells can be increased, and anemia reversed. “In thalassemia, red blood cell precursors die due to buildup of defective hemoglobin proteins,” explains Moura, a researcher at the French Institute of Health and Medical Research (INSERM). Using the experimental compound sotatercept, initially intended to treat osteoporosis, the researchers were able to increase the number of precursor cells that survived the critical stage and developed into mature red blood cells. Thiago Maciel and Michael Dussiot, researchers from Brazil and France respectively, tested the compound on mice that had been genetically modified to present symptoms of thalassemia. The results were promising (Nature Medicine, April 2014). The compound had already been administered to women with osteoporosis, making it possible to initiate human testing immediately. About 20 people with thalassemia had received the treatment by the end of April 2014. Eighty percent of those who received therapeutic doses showed improvement in their anemia. “The compound does not fight the cause of the disease, but it corrects the problem,” says Moura. “For now, we can say that it’s promising.” He believes that if sotatercept works against thalassemia, it might be useful against other forms of anemia.