USE OF GDF TRAP TO INCREASE RED BLOOD CELL LEVEL

摘要

PROBLEM TO BE SOLVED: To provide use of GDF traps to increase red blood cell levels.SOLUTION: In certain aspects, the present invention provides compositions and methods for increasing red blood cell and/or hemoglobin levels in vertebrates, including rodents and primates, and particularly in humans. The disclosure demonstrates that GDF traps may be used to increase red blood cell and hemoglobin levels. Variant ActRIIB polypeptides having a significantly decreased affinity for activin (e.g., activin A and/or activin B) relative to other ActRIIB ligands, such as GDF11 and/or myostatin, are referred to as GDF traps.