Red blood cells have the potential to do much more than carry oxygen around the body.
A group of scientists at the Whitehead Institute for Biomedical Research in Massachusetts has managed to modify the small, doughnut shaped cells to act as miniature drug delivery vehicles.
The research paper, called Engineered red blood cells as carriers for systemic delivery of a wide array of functional probes, explains how the research team genetically manipulated the red blood cells of mice to carry different proteins and then inserted them into the animals to see how they were received.
By also attaching the easily-tracked molecule biotin to the red blood cells, they were able to monitor where the cells travelled and how long the substances they were carrying lasted.
What they discovered was that the molecules lasted for much longer in the bodies of the mice when attached to red blood cells than they would have on their own.
“This shows that red blood cells have great potential,” says team member Hidde Ploegh. “They could be used to carry any number of substances and those substances could last for much longer than they would under normal circumstances. In principle, we could attach any disease-fighting molecule to the surface of a red blood cell.”
He adds that the cells last for several months in the body, rather than the several weeks that an injected biological substance would normally last for, so they could be used to extend the lifespan and thus the impact of the disease-fighting molecules. The idea is that red blood cells would be modified to carry out the exact task at hand, since all diseases require different molecules to fight them.
Another positive aspect of red blood cells for use in drug delivery is that they do not elicit a strong immune response. “We are tolerant of red blood cells and their waste products, so if a foreign object which would normally cause inflammation is attached to a red blood cell before it is inserted, it could be accepted in a normal way,” explains Ploegh.
“This is important because many important diseases, such as diabetes and multiple sclerosis, are caused by immune reactions to our own cells. So we could use red blood cells to manipulate someone's immune system to help them overcome these sorts of diseases in the future.”