Blood grown in a laboratory has been transfused into humans for the first time in a landmark clinical trial that U.K. researchers say could significantly improve treatment for people with blood disorders and rare blood types.

Two patients in the U.K. received tiny doses — equivalent to a few teaspoons — of the lab-grown blood in the first stage of a wider trial designed to see how it behaves inside the body.

The project, called RESTORE, is a collaboration between scientists from three universities in the United Kingdom, as well as from England’s National Health System Blood and Transplant (NHSBT). The goal is to supplement the natural blood supply with fabricated red blood cells, which are grown from human stem cells.

To make the blood, RESTORE scientists obtain a standard pint-sized blood donation from a human donor. They then use magnetic beads to separate about 500,000 stem cells out from the rest of the tissue. Over the span of three weeks, these stem cells are encouraged to multiply until they reach a population of about 50 billion, approximately 15 billion of which are considered to be at the appropriate stage of development for transplant. Because these cells are at this specific stage, researchers actually expect recipients’ bodies to accept the lab-grown blood at a higher rate than they would a standard blood transfusion.

“This world-leading research lays the groundwork for the manufacture of red blood cells that can safely be used to transfuse people with disorders like sickle cell,” said Dr. Farrukh Shah, medical director of Transfusion for NHS Blood and Transplant, one of the collaborators on the project.

“The need for normal blood donations to provide the vast majority of blood will remain. But the potential for this work to benefit hard to transfuse patients is very significant,” she added.

Image source: NDTV