LOUISVILLE, Ky. (AP) — Donated blood generally has a six-week shelf life, but University of Louisville researchers are testing a way to convert red blood cells into a longer-lasting powder that potentially could save the lives of soldiers, trauma patients and maybe even astronauts.

U of L professors Michael Menze and Jonathan Kopechek, as well as Ph.D. candidate Brett Janis, have spent two years developing this "freeze-dried" approach to storing blood, which has drawn interest from the U.S. military, NASA, emergency responders and other groups.

"So many people told us, 'We really want this. We really need this,'" Kopechek said.

Menze and Kopechek, with the help of Janis, as well as various U of L students, have devised a process of preserving red blood cells though freezing and dehydration. The cells are turned into a powder that remains viable at a wider range of temperatures than donated blood, which has to be refrigerated.

They believe their approach could make donated red blood cells more easily stored and transported, in addition to allowing them to be stockpiled for longer periods of time.

When someone donates blood, it is separated into different components, including plasma, platelets and red blood cells, said Dr. Dennis Williams, the Kentucky Blood Center's medical director.

Regulations require red blood cells, which carry oxygen throughout the body, to be used within 42 days. After that, they must be disposed of, although Williams said that doesn't happen often.

Williams suggested there could be benefits to using the freeze-dried red blood cells, although he said blood banks already have an efficient system of collecting, maintaining and transporting blood.

"If it became a standard way of processing and storing blood, it would definitely be helpful," he said. "It's easier than having to have refrigerators that you're constantly monitoring."

Menze, Kopechek and Janis said their freeze-drying process, if it proves to be effective once they test it in humans, could be a big help to the military, which often operates in extreme environments, making it even tougher to lug refrigerated cases of blood into the field.

NASA also has taken an interest in their research, Menze said. The federal agency is providing $275,000 in funding so they can test the process of rehydrating the freeze-dried red blood cells during flights that simulate zero gravity.

In particular, he said, NASA could be interested in the possibility of using this lightweight form of red blood cells for long-distance spaceflight, which is itself theoretical at this point but could involve a risk of radiation-induced anemia for astronauts.

"Microgravity can impact new technologies in unexpected ways," Stephan Ord, with NASA's Flight Opportunities Program, said in an emailed statement. "NASA sponsors suborbital flight tests so researchers can refine and mature their technologies before proposing them for further development or even implementation into future missions."

Here's the gist of how U of L's researchers are turning red blood cells into a powder that's easily stored in bottles or bags and can be quickly rehydrated for transfusion.

First, they mix red blood cells with a sugar called trehalose, which helps sea monkeys survive in dried-out environments and is also used for some vaccines and for food preservation, such as a certain kind of doughnut glaze.

"The biological clock literally stops. The moment you dry an animal out, it's (essentially) not aging anymore," Menze said. "So if we could do with blood what those animals can do in nature, ... we would be able to make blood way more accessible," including bringing it to regions of the world that lack available refrigeration or electricity.

After they combine the red blood cells and the trehalose, they put that mixture into a tube that flows through a device, which graduate student Emily Murphy helped develop, in which the red blood cells are exposed to ultrasound waves and gas microbubbles.

Those waves and microbubbles essentially punch temporary holes in the red blood cells, opening a gateway through which the preservative sugars enter.

Next, they freeze and then dehydrate the solution, eliminating any water and leaving behind only a powder that consists of the sugared-up red blood cells.

When they're ready to actually use the blood, they add water (which must be sterile) to the powder and mix them together.

And boom: They have liquid red blood cells again that are theoretically ready to be pumped into a patient. (Their team isn't testing this on people yet.)

Menze, an associate professor and assistant chairman of U of L's biology department, and Kopechek, an assistant professor of bioengineering, didn't expect their research efforts to intersect.

Menze studies animals that can live in extreme environments, such as sea monkeys, while Kopechek researches gene and drug delivery methods for treating illnesses such as cancer.

However, Janis — the Ph.D. candidate who works with Menze — spotted an opportunity to unite the professors' respective fields of work after he heard a presentation on Kopechek's efforts.

Now, two years later, they're making steady progress. They recently began their first tests on live subjects — in this case, rats, all of which have survived so far.

If testing their method of freeze-drying, rehydrating and transfusing red blood cells works in rats, the next step would be testing on larger animals such as pigs, Menze said. The phase after that would be clinical trials on humans, which could begin within the next three to five years.

Their approach to storing red blood cells ultimately would have to be approved by the U.S. Food and Drug Administration before it could be widely used for patients.

Dr. Dave Duncan, who serves as the EMS medical director for CAL FIRE, one of the world's largest fire departments, and also works for two air ambulance companies, said this approach to blood storage could save the lives of trauma patients, who face a significant risk of dying from rapid blood loss.

"Our brain dies early and rapidly as oxygen delivery falls off. And at the end of the day, loss of blood and drop in blood pressure means we're delivering less oxygen to tissues," he said. "Everything we do in trauma is centered around delivering oxygen to cells that are about to die, and red blood cells are the answer, or 'the antidote.'"

Duncan, who has provided input for U of L's research efforts, said the work Menze, Kopechek and their students are doing with freeze-dried blood "offers the biggest potential tool" to reducing the number of preventable deaths that occur while emergency responders are helping and transporting trauma patients.

"Red blood cells are a little like a time machine," Duncan explained. "If somebody's bleeding and we can add more red blood cells, we buy more time — and that might be enough time to get them to the operating room or to the emergency room."

Regulatory restrictions are the biggest impediment for emergency responders seeking to bring blood out into the field, he said, although the limited space available on both ground and air ambulances presents another formidable challenge.

He believes the freeze-drying approach could help overcome those issues, especially if the processed powder is treated more like a pharmaceutical and handled by companies rather than blood banks or hospitals.

Eduardo Nunes, vice president of quality systems, standards and accreditation for AABB, a nonprofit association that develops standards and provides accreditation for most U.S. blood banks, said there's nothing quite like what U of L's researchers are working on, which he called "novel" and "innovative."

"In general, I think there are a lot of pressures on the blood supply. This is a product with a limited shelf life," he said. "Anything that alleviates the pressure on the inventory is definitely appealing."

In terms of blood shortages, Nunes said there is a nationwide network of organizations that ensures blood gets to where patients need it, even when unexpected mass casualty events like the 2016 Pulse nightclub or 2019 Virginia Beach shootings happen.

There can be regional variations in blood availability, though, and elective surgeries may be postponed at times because of low supply, he said. But blood banks and hospitals across the country are consistently able to meet critically injured patients' needs.

As for the freeze-dried cells U of L researchers are working on, Nunes said it's hard to say at this point how that might be implemented because blood is subject to a lot of regulations, federal and otherwise.

"But when something comes along that has the potential to benefit patients ... (it's) incumbent on anyone with oversight to really understand how to make the best use of that," he said.

Lt. Col. Torree McGowan of the Oregon Air National Guard has been deployed for combat operations in Iraq and Afghanistan.

Soldiers have a better chance of surviving a critical injury on the battlefield in Afghanistan than they do in some more remote parts of the U.S., she said, because the military has developed an effective evacuation system that rapidly shuttles its members to the closest surgeon.

However, America is involved in military operations in more than 150 countries, which don't all have the kind of infrastructure the armed forces have developed over the years in Afghanistan. And members of the military who are injured and hemorrhaging, whether from a gunshot or a car crash, have a higher chance of survival if they can get access to new blood quickly.

The military operates in extremely hot and cold environments, and bringing donated blood into a combat situation is "nearly impossible" because it must be continuously refrigerated and has a narrow temperature range that must be maintained in order for it to remain viable, McGowan said.

"If it's something that's small enough and portable enough that they could bring it with them, this absolutely could save (soldiers') lives," she said of U of L's research, especially in areas with limited access to medical personnel and resources.

But McGowan sees this as a potentially vital tool not only for people who serve their country but also for civilians, noting that much of America is made up of rural areas that are hours away from the nearest trauma center.

"This could save lives back home as well," she emphasized.

There's still a lot of research and testing to be done before freeze-dried red blood cells could become part of the military's strategy for treating critical injuries or before it becomes a tool used stateside by emergency responders.

Regardless of whether the cells are being refrigerated or freeze-dried, there's a continual need for people to donate their blood to ensure enough is available for patients when they need it, said Martha Osborne of the Kentucky Blood Center.

"That's why it's so important for people to give regularly," she said. "There's still nothing that substitutes for a volunteer coming in and donating blood."

This article was written by Morgan Watkins from The Associated Press and was legally licensed through the NewsCred publisher network. Please direct all licensing questions to legal@newscred.com.