Scientists Uncover How Young Blood Rejuvenates Aging Brains

Image by : Gerd Altmann / Pixabay

The enticing concept of an easy method to reverse aging may soon turn into reality, thanks to groundbreaking discoveries by neuroscientists.

Three interventions have been identified to slow down, and potentially reverse, the biological aging process. These include transfusions of young blood, a hormone present in our bodies known as klotho, and regular physical exercise.

Interestingly, platelets are a common factor linking all of these methods.

Platelets are blood cells that act as alarms for your immune system when your body is injured, and they play a crucial role in forming clots to aid in the healing process.

Scientists from around the world have made a significant discovery: a group of molecules released by platelets, known as platelet factor 4 (PF4), is the crucial final step in delivering the benefits of three activities – transfusions of young blood, injections of the hormone klotho, and regular exercise – to the brain. What's even more remarkable is that PF4 has the potential to help the brain reverse its aging process.

The release of PF4 occurs after injections of blood plasma (blood without the red blood cells), klotho injections, or during physical exercise.

In experiments with 22-month-old mice, equivalent to 70-year-old humans, injections of young blood plasma containing PF4 reversed their cognitive age. In fact, PF4 brought their cognitive age down to that of individuals in their late 30s or early 40s. Meanwhile, young mice given PF4 exhibited enhanced cognitive abilities.

These groundbreaking findings were independently made by three separate research teams. Upon realizing that PF4 was the key ingredient behind these benefits, the teams collaborated to publish their papers simultaneously.

The research on young blood and klotho injections was conducted by two distinct teams at the University of California San Francisco (UCSF), while scientists at the University of Queensland in Australia led the study on exercise.

The findings from these three studies have been published in the journals Nature, Nature Aging, and Nature Communications.

Dr. Dena Dubal, the UCSF professor who spearheaded the study on klotho, expressed the surprise of the researchers, stating, "When we realized we had independently and serendipitously found the same thing, our jaws dropped. The fact that three separate interventions converged on platelet factors truly highlights the validity and reproducibility of this biology. The time has come to pursue platelet factors in brain health and cognitive enhancement."

Revitalized with Young Blood

In studies on aging, scientists frequently perform blood transfusions from a young mouse to an old mouse through a procedure called parabiosis. This is done because young blood is known to have rejuvenating effects on animals, promoting more resilient muscles and a more flexible brain.

However, researchers at the UCSF Bakar Aging Research Institute discovered that plasma alone could replicate these benefits and reverse the aging process.

The researchers injected old mice with young blood plasma, which contains a higher concentration of PF4 compared to old blood. As a result, the old mice experienced rejuvenation, displaying improved performance in memory and learning tests compared to their counterparts.

In subsequent experiments, the scientists injected the PF4 platelets alone and observed that they were equally effective in reducing inflammation in the aging bodies and brains of the old mice.

A protein-driven brain boost

The second UCSF team, led by Dr. Dubal, discovered that an injection of klotho triggers the release of PF4 in the bodies of animals.

About a decade ago, Dr. Dubal demonstrated that the klotho protein plays a role in maintaining health as we age by rendering our brains resistant to degeneration. Despite her earlier findings, injecting klotho into the body did not reach the brain. This led the team to explore what other factor might be facilitating the benefits of klotho to brain health.

Upon injecting klotho into the animals, the researchers observed a significant impact on the brain, with PF4 enhancing the formation of new neural connections to improve memory formation. This brain-boosting effect was evident in both young and old animals. Consequently, the researchers are now exploring the therapeutic use of klotho injections.

Unveiling the Cognitive Benefits of Exercise

The University of Queensland team found that PF4 was released into the bloodstream following exercise, and similar to the other teams, this release was associated with improved brain performance.

While not requiring injections, this exercise-related option may be considered more suitable for young individuals as a preventive measure. On the other hand, for older individuals with mobility issues, plasma or klotho injections would likely be more effective interventions against cognitive decline.