Thousands of people in the United States die each year due to severe blood loss, often before they reach an emergency room.
To help reduce the number of trauma deaths, a Washington University research team is working to develop an artificial blood substitute. The freeze-dried red powder, which can be reconstituted with sterile water, is intended to keep patients alive until they’re able to reach a hospital.
The search for an artificial blood substitute has been ongoing for the past 50-60 years, according to Allan Doctor, pediatrics professor at Washington University School of Medicine.
Early efforts involved removing hemoglobin, the oxygen-carrying protein, from red blood cells, purifying it and injecting it into the patient’s bloodstream.
“The problem is if you put hemoglobin into the bloodstream outside of a red blood cell, it’s very toxic,” Doctor said. “People tried to chemically modify hemoglobin to prevent these problems, but there was really no way to fix the toxicity without breaking the function [of the protein].”
Rather than modifying hemoglobin, Doctor and his colleague Dipanjan Pan of the University of Illinois Champaign-Urbana decided to try a different route: encasing it in a synthetic polymer shell.
The artificial “cells," called ErythroMer, have the same flattened disc-like shape as a red blood cell, but they’re about one-fiftieth the size. The hemoglobin inside is purified from outdated blood samples that have been screened for infection at blood banks. Although the blood itself is no longer usable, the hemoglobin protein remains viable.
Because real blood contains living cells, it must stay refrigerated and has a shelf life of 42 days. The artificial blood powder, however, can be stored at room temperature for extended periods of time.
The powder is not a replacement for donor blood cells, Doctor said, but rather a stopgap until the patient can get to an emergency room.
“The idea is to push transfusion out into the field setting where people who have massive blood loss can be stabilized before they’re brought to the hospital,” said Doctor, whose research is partly supported by the U.S. Department of Defense.
The team filed their first patent in 2013 and tested the product in mice in 2014. They have since formed a company called KaloCyte (Greek for “good cell”) to continue producing the blood substitute.
Before human testing can begin, Doctor and his colleagues will have to obtain an Investigational New Drug license from the U.S. Food and Drug Administration. As part of the process, the team will need to prove the blood substitute is safe and effective in animals.
Though the possibility of human use is still years away, Doctor said several U.S. agencies have already expressed interest in using the blood substitute.
“The Department of Defense is very interested in including a blood substitute in each soldier’s medical kit,” he said. “We’ve even gotten a call from NASA who’s interested in using it to supply the Space Station and of all things, a Mars mission. That’s the ultimate austere remote setting: Mars.”
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