A group of University of Iowa researchers hopes to help increase the shelf life of blood.

Currently, blood for transfusions and other treatments is good for only 42 days. To study whether longer-lasting blood is inherited, researchers are enlisting the help of 14 sets of twins.

"We can appreciate that anything we put in the refrigerator, such as cottage cheese for an example, over a period of time it decays, and red blood cells are no exception," said UI DeGowin Blood Center medical director Thomas Raife, who is leading the study.

Doctors hope to find out if the rate at which red blood cells decay is inherited. Knowing that will help them predict cells’ longevity, said UI neonatology Professor Jeff Murray, who oversees the genetics lab for the study.

"Many traits we think of as normal, such as height and blood pressure, have a strong genetic component," he said.

Successfully storing red blood cells is one of the biggest concerns in blood banking and transfusion, Raife said. The cells are stored for 42 days, during which they begin to deteriorate, change shape, and lose hemoglobin, making them less effective for transfusion.

Murray said the cells’ longevity is critical for blood transfusions.

"If we can find safer ways to store blood longer and more safely, it will have important clinical implications, and genetics is one tool to find these factors," he said.

The 14 pairs of twins who volunteered for the study donated blood that will be sampled and analyzed every two weeks, Raife said.

"We should see the same rate of decay in red blood cells in a pair of identical twins, and in non-identical twins, we should see different rates," Raife said. "Twin studies are very powerful ways of studying inheritance of traits because it allows you to separate nature versus nurture."

The Institute for Clinical and Translational Science in the UI Carver College of Medicine is funding the study with a $50,000 grant.

Co-investigator Garry Buettner is analyzing the blood from the twins. He said red blood cells also remove oxidants, waste products formed by white blood cells fighting infections.

The scientists are investigating the capacity of red blood cells to remove the oxidants over time, he said, and testing if the starting capacity is different between individuals — how fast it declines while being stored, for example.

"As storage time increases, things get used up in the red blood cells and capacity goes down," Buettner said.

This unique twin study follows a 1960s University of Chicago study suggesting some people’s blood may deteriorate more quickly than others when stored.

But Raife said finding that information was a complete accident.

"It was a bit of serendipity," he said. "I was looking up an answer to a very simple clinical question in a textbook, and I ran across a paragraph that said red blood cells’ storage had a heredity component, which was a completely new idea to me."

If the results — which will arrive in May — should prove that red blood cells storage is inherited, Raife will likely collaborate on a larger study to determine what specific genes are responsible for blood storage.

Raife said the genetic approach is a practical way of looking at blood storage.

"A genetic approach is a completely different way of understanding the storage properties of blood," he said. "And the results [of the twin study] so far look promising."