Sickle Cell Disease

Sickle cell disease is a term that refers to sickle cell anemia, sickle cell-hemoglobin C disease, sickle cell-thalassemia or any other combination of these conditions. Sickle cell anemia is an inherited, non-contagious blood disease which can cause bouts of pain, damage to vital organs, repeated infections, and for some, death in childhood or early adulthood. These painful crises and infections necessitate frequent hospitalizations in patients with severe cases of the disease. It afflicts as many as 150,000 North-Americans overall.

Oxygen-carrying red blood cells are normally round and flexible. In sickle cell anemia, red blood cells become distorted into curved forms (resembling the letter "j") under conditions of reduced oxygen. When this occurs within the small blood vessels (capillaries), the sickle cells partially or completely block the blood supply to parts of the body. Any part of the body or organ may be affected, but frequently, the heart, lungs, kidney, spleen, hips and, less frequently, the brain are damaged. This situation results in a shortage of red blood cells, which can cause the patient to be pale, short of breath and easily tired. Victims of this disease may be prone to certain infections which can worsen their condition, and their physical growth and development are often slower than normal. In addition, some sickle cell patients must receive regular blood transfusions. Iron from the breakdown of red blood cells gradually builds up and can poison vital organs in patients who receive frequent transfusions.

Because of biomedical research using animals, a number of therapies exist for treating the symptoms of sickle cell disease. These treatments have greatly improved the survival and quality of life for many patients. In children with sickle cell anemia, acute illness in the form of bone or joint pain, for example, is often caused by an infection. Prompt treatment of the infection with antibiotics, such as penicillin, which were developed and tested in animals, will often prevent or shorten these illnesses in humans. Pain is also a feature of sickle cell anemia and may be relieved by a variety of analgesics, all of which were developed and tested in animals to determine their safety and proper dosage before being allowed for human consumption. In addition, pain management techniques developed in animal patients have been extremely beneficial to many victims of sickle cell disease.

Recently, researchers have developed a genetically-engineered mouse with a condition similar to sickle cell disease, making this the first true animal model for the disease. With an animal model that is able to develop the disease, researchers can now test possible therapies, including transplanting normal hemoglobin genes or developing innovative drug strategies against the disease. Now that the mouse model for sickle cell disease is available, for example, research is under way to develop a technique for inserting a normal gene into the blood-forming cells of sickle cell patients. This gene therapy is in the early stages of research.

With all of these avenues of research being pursued, and with the help of the animals which make this research possible, great progress is being made against sickle cell disease. With continued animal research, a cure is something that we can hope for.