Sickle mice turn anemic.

Sickle mice turn anemic

The race to develop an animal model for sickle cell anemia headed into the final stretch this week as researchers reported genetically engineering the first laboratory animals displaying symptoms of the hereditary disease. Previous experiments had yieldded mice whose red blood cells contained the human gene for sickle cell anemia but who failed to show any signs of the disease (SN: 1/20/90, p.45).

Thomas M. Ryan of the University of Alabama Schools of Medicine and Dentistry at Birmingham and his colleagues started by adding the human gene for sickle cell anemia to mouse embryos. As in previous efforts, the mice expressed the abnormal hemoglobin that is the hallmark of the disease, but they also produced moderate amounts of normal mouse hemoglobin, staving off the illness. Ryan's group overcome this obstacle by breeding these mice with others harboring a genetic disease called thalassemia, which prevents production of normal hemoglobin.

Offspring from these crosses have clinical profiles resembling those of humans with sickle cell anemia. They exhibit mild anemia and enlarged spleens, and their blood cells sickle under low-oxygen conditions. The hybrid mice may prove useful in tests of new anti-sickling drugs and gene therapies, the researchers assert in the Feb. 2 SCIENCE.