Researchers Find New Genetic Target for Sickle Cell Disease Therapy
Researchers have identified a gene that directly affects the production of a form of hemoglobin that is instrumental in modifying the severity of the inherited blood disorders, sickle cell disease and thalassemia. The discovery could lead to breakthrough therapies for sickle cell disease and thalassemia, which could potentially eliminate the devastating and life-threatening complications of these diseases, such as severe pain, damage to the eyes and other organs, infections, and stroke.
Hemoglobin is the protein in red blood cells that carries oxygen to the body's tissues. In sickle cell disease, hemoglobin is abnormal and sticks together. The red blood cells become stiff and sickle shaped, causing them to block blood vessels and rob tissues of necessary blood and oxygen. In thalassemia, the body has trouble producing adult forms of hemoglobin. Other studies have shown that in patients with sickle cell disease, those who continue to produce fetal hemoglobin (HbF) have much milder forms of sickle cell anemia. For years, scientists have sought ways to increase HbF production in patients with sickle cell disease and thalassemia. Researchers report that by suppressing a gene called BCL11A, HbF production improves dramatically. Their findings provide new insights into the mechanisms involved in the body's switch from producing HbF to adult hemoglobin and identify a potential new target for therapies that could dramatically alter the course of sickle cell anemia and thalassemia.
The researchers built upon their recently reported results of genomewide association studies that identified several gene variants associated with HbF levels. BCL11A was found to have a great effect on HbF levels. In the follow-up study, they report that BCL11A encodes a transcription factor that directly suppresses HbF production.
A drug therapy that increases HbF levels enough to modify the severity of sickle cell disease is currently available. The drug, hydroxyurea, was approved by the Food and Drug Administration in 1998 to prevent pain crises in adults with sickle cell disease after studies have shown that it increases HbF production, reduces the damaging effects of sickle cell disease, and improves some aspects of quality of life. Use of hydroxyurea is limited, however, in part because not all patients respond to the drug, and there are short- and long-term adverse effects. New therapies targeting BCL11A would be the first to directly affect the natural processes involved in increasing HbF.
Sickle cell disease is the most common inherited blood disorder. In the United States, it affects approximately 70,000 people, primary African Americans. Worldwide, sickle cell anemia affects millions of people and is found in people whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries, India and Saudi Arabia. The pain and complications associated with sickle cell disease can have a profound impact on patients' quality of life, ability to work, and long-term health and well-being. In addition, people with sickle cell disease have a shortened life expectancy because of infections, lung problems, and stroke.
Treatments developed over the past 3 decades have led to the doubling of the life expectancy of sickle cell disease patients between 1972 and 2002. These treatments include medications, blood and bone marrow transfusions, and other procedures to relieve or prevent complications. Until now, however, scientists could not directly target processes known to affect the severity of sickle cell disease.
For more information, contact http:www.nhlbi.nih.gov/meetings/workshops/Sickle-Cell-Announcement.htm or http://consensus.nih.gov/2008SickleCellCDC119main.htm.
US Supreme Court Clears the Way for State Tobacco Suits
By a vote of 5-4, the US Supreme Court in December 2008 rejected Big Tobacco efforts to block state courts from hearing cases that use consumer protection laws to litigate against tobacco companies for use of deceptive terms of light or low tar in advertising tobacco products. While the decision directly impacts a case being heard in Maine, the Court's decision effectively clears the way for state courts to hear several cases pending against tobacco for using light or low tar to advertise tobacco products. In the case Altria Group v Good, the tobacco industry claimed that state courts had no standing in tobacco labeling claims, and the Federal Cigarette Labeling and Advertising Act gives the federal government sole jurisdiction over tobacco labeling cases. The industry further stated that claims of light and low tar were based on federally approved test conducted by the Federal Trade Commission. The plaintiffs countered that tobacco industry documents proved tobacco companies knew smokers had no health benefit from smoking light and low-tar cigarettes. In rejecting the claim, the court noted that Maine did not use state tobacco law but relied on state false advertising and consumer protection statute to pursue the case. The case now returns to Maine state courts for a jury trial. For more information, contact [email protected].
"Old Blood" Linked to Infection
Blood stored for 29 days or more, nearly 2 weeks less than the current standard for blood storage, is associated with a higher infection rate in patients who received transfusions with the blood. In a new study presented at CHEST 2008, the 74th annual international scientific assembly of the American College of Chest Physicians, researchers found that patients who received transfusions with blood stored for 29 days or more were twice as likely to suffer from nosocomial infections, including pneumonia, upper respiratory tract infections, and sepsis, with the oldest blood being associated with the most infections. Currently, federal regulations allow red blood cells to be stored up to 42 days, after which they must be discarded. For more information, visit the American College of Chest Physicians Web site at http://www.chestnut.org.
Simple Blood Test Predicts Obesity
According to a new research from the Monell Center, the degree of change in blood triglyceride levels following a fatty meal may indicate susceptibility to diet-induced obesity. The findings open doors to new methods of identifying people, including children, who are at risk for becoming obese. Triglycerides are a form of fat that is transported in the blood and stored in the body's fat tissues. They are found in foods and also are manufactured by the body.
The global obesity epidemic is thought to be caused in part by consumption of a diet high in fat and carbohydrates, which promotes weight gain. This propensity to gain weight and become obese when consuming a high-fat diet is at least partially controlled by genes, with some individuals gaining more than others while eating the same diet.
There currently are no simple biomarkers for predicting susceptibility to diet-induced obesity and thus no clinical tests that assist physicians in identifying those at risk for becoming obese. The current findings suggest that a change in blood triglyceride levels may someday be used. Future studies will entail a thorough investigation of the mechanism behind differences in the change in blood triglycerides.
For more information, visit http://www.monell.org.