Researchers at The Ohio State University have made significant progress in improving the safety and effectiveness of artificial blood, also known as red blood cell substitutes. The key to their success is creating larger molecules that don’t leak from blood vessels into tissue, causing cardiovascular side effects.
A team of researchers from Ohio State University claims to have discovered the best way to produce red blood cells artificially, offering a promising solution to the challenge of blood donation shortages. The new formula for synthetic red blood cells was detailed in an article published in the scientific journal Biomacromolecules.
Blood loss is primarily treated by transfusing donated blood, but this can be problematic in areas where blood isn’t readily available or where there’s not enough time to screen for patient blood type compatibility. Artificial blood products offer greater flexibility for medical professionals in treating patients, but past generations of these substitutes have often resulted in negative side effects.
To find a better solution, researchers at Ohio State focused on identifying the right size for red blood cell substitute molecules. They found that larger molecules resulted in fewer side effects and a particular size range that had better cardiovascular benefits than previous generations of the material.
The key to the formula lies in the size of the molecules, which must not be too small to “leak” through fabrics, as has happened with other products of this type. Previous attempts to create artificial blood, such as polymerized human hemoglobin, failed tests due to side effects such as high blood pressure, narrowing of blood vessels, and tissue damage.
Polymerized human hemoglobin (PolyhHb), a red blood cell substitute that had been explored in previous clinical trials, was tested in four different-sized brackets to determine the target therapeutic size. Guinea pigs were used as models because their antioxidant status is more similar to that of humans than other rodents.
The Ideal Synthetic Blood for Emergencies
The new formula for synthetic red blood cells offers a promising solution for emergencies, such as the first transfusion after an accident performed by the medical rescue team itself. The compound would provide a short reprieve until the patient arrived at a medical facility where their blood would be tested and transfused with the proper blood type.
One of the advantages of the new product is that synthetic red blood cells do not have any type of surface antigen, meaning blood would be universal and can be used in all individuals. While the product cannot yet replace conventional transfusions, the research offers a promising first step toward whole blood.
Animal Testing Offers Promising Results
The new formula for synthetic red blood cells has only been tested in animal models, specifically guinea pigs, but the results have been promising. According to Alisyn Greenfield, lead author of the study, “There is a specific size range that offers better benefits when seeking to prevent the cardiovascular effects observed in previous generations of the material.”
In its current dimensions, the molecules do not escape from the vessels and do not cause their narrowing. While the product is not yet approved for use in humans, the scientists are planning new research steps, and one day, the product may be tested on humans.
Although red blood cell substitutes aren’t meant to replace blood entirely, they offer potential benefits when transfused into a person soon after injury. They could buy the person enough time to be transported to a medical facility to receive a blood transfusion.
British Researchers Testing Another Version of Artificial Red Blood Cells
In parallel, British researchers are also testing another version of artificial red blood cells in humans as part of the randomized clinical trial Restore. Funded by the National Institute for Health and Care Research in the United Kingdom, the initial results of the research are yet to be disseminated.
While the product is not yet approved for use in humans, animal testing has shown promising results, and further research is planned. The development of the ideal synthetic blood may offer a universal solution to blood donation shortages.
However, artificial blood is still a long way from commercialization. While it can be stored at room temperature for several years compared to the 42-day storage period for donated blood, it doesn’t come close to replicating the lifetime of real blood cells. A typical red blood cell circulates in the human body for about 120 days, while the materials in current blood substitutes only have a half-life of about 24 hours after administration.
Further study is needed to more accurately determine the safety and efficacy of artificial blood substitutes in clinical settings. The study was supported by the National Institutes of Health, and the co-authors included researchers from the University of Maryland.
Source: Biomacromolecules and Ohio State University
