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Getting people to donate blood is extremely important for blood banks and hospitals. Everyday, blood transfusions are done to save people's lives. Even though blood transfusions are used with the intention of improving people's health, it is not 100 percent effective. Unfortunately, a blood transfusion could result in worsening a patient's symptoms due to the fact that the blood starts to work less effectively after being stored for too long. According to researchers, when blood is left unused, its ability to distribute oxygen throughout the body starts to weaken, which can cause tissue hypoxia. Due to this complication from blood transfusions, researchers from the Case Western Reserve University in Cleveland, OH headed by Jonathan Stamler, studied ways of improving or maintaining the quality of stored blood.

Stamler and his colleagues approached this complication by studying how red blood cells distribute oxygen throughout the body. They theorized that after a transfusion, there could be a decrease in nitric oxide levels that then causes red blood cells to lose their ability to deliver oxygen. The researchers knew that the presence of nitric oxide is important because it binds to the cell's hemoglobin and creates S-nitrosohemoglobin (SNO-Hb). SNO-Hb allows blood vessels to dilate, which makes it easier for the oxygen to reach the cells. When blood is stored, the team found that SNO-Hb levels decreased.

Based on the understanding of how red blood cells deliver or fail to deliver oxygen, the researchers decided to experiment with banked blood by adding nitric oxide using a process called renitrosylation. They then performed blood transfusions on mice, rats and sheep with one-day blood, seven-day old blood and 14-day old blood. For the rodents, the researchers found that the renitrosylated blood was able to help them maintain normal blood oxygen levels. The rodents that received untouched blood had lower oxygen levels. The researchers then studied the effects of renitrosylated blood on anemic rodents and anemic sheep. The researchers found similar effects in these animal samples as well.

This study suggests that nitric oxide could be key in keeping stored blood useful. If more study is done, adding nitric oxide might be able to help improve the patient's wellbeing post-transfusion. The study was published in the Proceedings of the National Academy of Sciences.