June 17 (UPI) -- Red blood cells contain a protein that may help slow the aging process and protect against cognitive decline, a study published Thursday by the journal PLOS Biology found.
In the study, performed in mice, those lacking the protein ADORA2B in their blood showed signs of accelerated aging, including poor memory and hearing loss.
Removing ADORA2B from the blood led to faster declines in memory, delays in sound processing and increased inflammation in the brain.
"Red blood cells are the most abundant cell [in the body] and they carry approximately 1 billion molecules of oxygen in humans, [so they] play a vital role to maintain cellular function and survival of every tissue within our body," study co-author Dr. Yang Xia told UPI in an email.
"Our findings revealed that ADORA2B on red blood cells has a significant role to counteract aging and that chronic insufficient oxygen supply is an underestimated key factor promoting aging and function decline," said Xia, a professor of biochemistry and molecular biology at the University of Texas-Health Science Center in Houston.
One in nine adults in the United States experience cognitive decline as they age, a number that has increased in recent decades with the rise in life expectancy, according to the Centers for Disease Control and Prevention.
More than 6 million people in the United States have dementia-related disorders, including Alzheimer's disease, the Alzheimer's Association estimates.
In conducting their research, Xia and her colleagues theorized that, because the amount of oxygen in the blood also declines with age, aging in the brain might be naturally held at bay by ADORA2B, an adenosine receptor, which is a protein found on the membrane of red blood cells that helps release oxygen to the body.
For this study, researchers bred mice that lacked ADORA2B in their blood and compared various behavioral and physiological measures with those of mice with higher levels of the protein.
As the mice aged, the signs of cognitive decline -- including poor memory, hearing loss and brain inflammation -- were higher in the those lacking ADORA2B, the researchers said.
In addition, after experiencing a period of oxygen deprivation, the behavioral and physiological effects on young mice without ADORA2B were much greater than those on normal young mice, they said.
More research is needed to determine whether ADORA2B levels naturally decline with age and whether treatment with drugs that activate the protein can reduce cognitive decline in normal mice, according to Xia and her colleagues.
Other recent studies have indicated that hyperbaric oxygen treatments can help combat the aging of blood cells and even reverse the aging process in healthy aging adults.
"It is known that [brain] cells are extremely sensitive to insufficient oxygen supply [and] chronic insufficient oxygen availability can ultimately lead to ... permanent impairment of cognition and hearing," Xia told UPI.
"Thus, our finding immediately highlights that enhancing oxygen delivery mediated by ADOAR2B signaling is likely a new rejuvenating approach."