Rescuing red cells to boost blood supply
The human body normally takes about a week to replace a mature red blood cell, but after a major blood loss it can replenish the supply within only a few days. Physicians and researchers have long marveled at this ability, noting that much of the credit goes to a hormone called erythropoietin. When released by the kidneys after a blood loss, or when given as a drug, erythropoietin enhances red-cell production in the bone marrow. But just how it works has remained unclear.
Now, hematologists at Vanderbilt University Medical Center in Nashville provide evidence that erythropoietin works not by initiating new red-cell production but by preventing the "programmed death" of very young red cells in bone marrow.
Mark J. Koury and Maurice Bondurant used a unique system of cultured, immature red blood cells from mice, which mimics conditions in the bone marrow. Their research indicates that many of the billions of red-cell precursors produced in marrow every day are systematically destroyed before they develop into mature cells. …