Purdue News

February 27, 1985

Purdue Scientists Find Key To Aging Cells

West Lafayette, Ind.– Scientists at Purdue University have unraveled one of the mysteries of aging by discovering how the body recognizes and removes "old" blood cells from circulation.

The discovery may be used to develop ways to prolong the shelf life of blood stored in blood banks and improve treatment for diseases such as sickle cell anemia, says chemistry Professor Philip Low, who directed the research effort.

"Scientists have long recognized that there are antibodies designed to remove old cells from circulation. What we didn't know was how the antibodies distinguished old cells from younger cells," says Low.

Low's team discovered a series of changes that occur in the composition of aging red blood cells to trigger a reaction from antibodies, which absorb the cells and remove them from circulation.

The researchers are now experimenting with ways to slow down and accelerate this process.

In his studies, Low traced a series of subtle changes in cells that had been in circulation an average of 120 days.

"As the cell ages, a protein called hemoglobin changes form, causing another key protein—band 3—to cluster within the cell membrane," he explains.

"The presence of these clusters provides the recognition site for antibodies directed against aging cells. The antibodies then bind to the cell and trigger its removal from circulation."

Low believes a similar process occurs to remove abnormal cells, such as those present in the hemolytic disease, sickle cell anemia.

"A number of diseases caused by unstable hemoglobins seem to promote an accelerated aging process. In these instances, the hemoglobin denatures earlier, resulting in band 3 clustering and the consequent premature removal of blood cells."

Understanding how these cells are recognized and removed from circulation may help improve treatment for such diseases, says Low.

In addition, knowledge of this process may someday lead to methods of altering the rate at which cells age, Low adds.

"Perhaps by interfering with the natural clustering of band 3 during cell aging, we could extend the shelf-life of blood stored at blood banks beyond its present 35- to 49-day limit," he says.

Because band 3 is present in many cells throughout the body, Low believes his discovery could have general significance in understanding the aging process.

A full report of these findings is published in a February issue of "Science" magazine by Low and his coworkers, Stephen Waugh, Karen Zinke and Detlev Drenckhahn.

Low is now completing a follow-up study which documents how the process is used to remove abnormal blood cells.

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