In a world’s first, red blood cells grown in a laboratory have been transfused into human recipients as part of a clinical trial, as reported by BBC News on November 7. The RESTORE trial is a UK research initiative led by NHS Blood and Transplant (NHSBT) and the University of Bristol that aims to assess the viability of manufactured blood, including understanding its lifespan compared to blood infused from a donor.
To manufacture the red blood cells, magnetic beads were applied to donated blood, capturing erythroid progenitor cells that were then differentiated into mature red blood cells. These cells are isolated by filtration then given to recipients who are unrelated to the original blood donor; this is called an allogeneic transfusion.
The entire process is technically challenging and expensive, so if approved for clinical use, manufactured blood will be limited to a small number of patients with complex transfusion needs. The majority of blood transfusions will continue to rely on blood donors.
Thus far, two people have received the transfusion, and the trial aims to test at least 10 healthy volunteers. Each person receives 5–10 mL of normal and lab-grown blood that is radioactively tagged to monitor the blood’s lifespan. The researchers hypothesize that since the lab-grown red blood cells are newly-differentiated from stem cells, they should last significantly longer (about 120 days) than a normal blood transfusion containing a mixture of older and younger blood cells.
If manufactured blood indeed lasts longer, then fewer blood transfusions will be needed by people with blood disorders and chronic illnesses, reducing iron overload and its serious complications. Therefore, the success of the RESTORE clinical trial could be transformative for patient care.