“The bunny huddled in a black metal cage, a catheter going straight into its carotid artery. Days before, a portion of its blood had been siphoned out and replaced with an experimental blood substitute called ErythroMer. It is decidedly not milk. Developed by Allan Doctor, a bespectacled 61-year-old physician-researcher at the University of Maryland (UMD) School of Medicine, and colleagues, ErythroMer is made from ‘recycled’ human hemoglobin—the protein in red blood cells that carries oxygen from the lungs to the rest of the body—wrapped in a membrane to mimic a tiny cell. In the rabbit, the transfusion appeared to be working. The animal’s heart rate and blood pressure, displayed on a small monitor nearby, looked just fine.

Doctor is as fervent an advocate for hemoglobin-based oxygen carriers (HBOCs), as ErythroMer and its predecessors are more formally known, as Thomas was for lacteal transfusions. Donated blood has a shelf life of just 42 days. There’s also not enough, even in developed countries with well-organized blood donation systems: In January 2022, the American Red Cross, which distributes 40% of the country’s donor blood, declared the first-ever national blood crisis, as its supply—especially precious O-negative blood, the universal type—dipped dangerously low. Meanwhile, hemorrhagic shock caused by severe blood loss kills some 20,000 people in the U.S., and 2 million globally, every year.

An artificial ‘blood’ could, perhaps, fill the void.”

From Science.