Diluting Plasma Slows Aging, New Mouse Study Suggests

University of California, Berkeley researchers have recently published a mouse model study that shows age-reversing effects can be achieved by diluting the blood plasma of old mice.

In 2005, University of California, Berkeley, researchers made a surprising discovery by stitching together a young and and old mouse like conjoined twins. Sharing blood and organs between the mice, scientists rejuvenated tissues and reverse the signs of aging in the old mice.

This conjoined twin mouse model study led to the idea that young blood contains special proteins, which deliver a ‘fountain of youth’ effect. And biohackers got the idea that getting transfusions from young donors aka “blood boys” could slow aging.

Problem is mouse studies are not a strong signal and exploratory. A follow on mouse model study conducted by the same research team, now shows simply diluting the blood plasma of old mice achieves age reversing effects.

Here’s how parabiosis became a thing:

Early 2000s – Senior researcher and professor of bioengineering Irina Conboy and Michael Conboy have a hunch that our body’s ability to regenerate damaged tissue remains with us into old age in the form of stem cells. But that somehow these cells get turned off through changes in our biochemistry as we age.

2005 – Conboy lab publishes study showing that making conjoined twins from the old mouse and a young mouse reversed many signs of aging in the older mouse. Many researchers seized on the idea that specific proteins in young blood could be the key to unlocking the body’s latent regeneration abilities.

2016 – a second follow-up study finds young blood does not reverse aging in old mice. Tissue health and repair dramatically decline in young mice when half of their blood is replaced with blood from old mice.

The study suggests to Irina Conboy that young blood by itself will not work as effective medicine. Rather the idea that emerges is that inhibitors in old blood could be a target to reverse aging.

In this 2016 study, Conboy and colleagues developed an experimental technique to exchange blood between mice without joining them so that scientists can control blood circulation and conduct precise measurements on how old mice respond to young blood, and vice versa.

In the new system, mice are connected and disconnected at will, removing the influence of shared organs or of any adaptation to being joined. One of the more surprising discoveries of this study was the very quick (within 24 hours) onset of the effects of blood on the health and repair of multiple tissues, including muscle, liver and brain.

June, 2020 – A new study finds that diluting blood in old mice by replacing half of the plasma with a saline and albumin mixture was able to reverse aging in the brain, liver, and muscle.

In a press release statement Irina Conboy, a professor of bioengineering at UC Berkeley who is the first author of the 2005 mouse-conjoined twins paper and senior author of the new study explains the results:

“There are two main interpretations of our original experiments: The first is that, in the mouse joining experiments, rejuvenation was due to young blood and young proteins or factors that become diminished with aging. But an equally possible alternative is that, with age, you have an elevation of certain proteins in the blood that become detrimental, and these were removed or neutralized by the young partners.”

In the years since the exploratory 2005 study, scientists have spent millions to investigate the potential medical properties of youthful blood with enterprises emerging to infuse old people with young blood.

“What we showed in 2005 was evidence that aging is reversible and is not set in stone,” Irena Conboy said in a UC Berkeley press release. “Under no circumstances were we saying that infusions of young blood into elderly is medicine.”