[Reading Science] Discovered the Secret of Young Blood That Rejuvenated Old Mice

University of California Research Team Identifies Causative Protein
PF4 Protein in Blood Heals Wounds
Confirmed Anti-Aging Effects Including Cognitive and Immune Function Improvement

A protein in the blood that functions to heal wounds has been found to have excellent effects in anti-aging, attracting attention.

A research team from the Department of Anatomy at the University of California, San Francisco, announced these research results in the international journal Nature on the 16th. The team focused on the role of Platelet factor 4 (PF4). PF4 has been well known for its role in wound healing, such as blood clotting and repairing damaged blood vessels. Recently, scientists have been paying attention to whether PF4 can treat cognitive impairments caused by Alzheimer's dementia and other conditions occurring during the aging process. In particular, about 10 years ago, some scientists discovered that when blood from young mice was transfused into old mice, it could promote so-called rejuvenation, such as restoring learning ability, which led to active research on the causative substances and mechanisms. In this process, PF4 was identified as a strong candidate because its levels were found to be much higher in the blood of young mice than in old mice.

The research team injected PF4 into the blood vessels of old mice, and as a result, it was confirmed that the amount of various types of immune cells increased and changed to a ratio similar to that of young mice. In some immune cells, gene expression patterns even reverted to those of their youth. Notably, although PF4 did not cross the blood-brain barrier, its impact on the immune system indirectly caused changes in the brain. In the brains of old mice injected with PF4, inflammation damage in the hippocampus was reduced. The hippocampus is particularly vulnerable to aging and is a site where inflammation occurs. Additionally, synaptic plasticity?the strength of connections between brain nerve cells?was enhanced. Old mice injected with PF4 showed superior cognitive abilities compared to other mice, demonstrating excellent ability to identify and remember safe resting spots while navigating a maze.

Two other papers published on the same day also presented research results showing that PF4 alleviates aging phenomena. Another research team from the University of California, San Francisco, confirmed through a paper published in Nature's sister journal Nature Aging that PF4 strengthens connectivity between brain cells. Additionally, a research team from the University of Queensland in Brisbane, Australia, published research in Nature Communications showing that PF4 is involved in the formation of new brain nerve cells.

Nature explained, "Some pharmaceutical companies are already developing anti-aging treatments based on these findings," adding, "Since a decrease in PF4 levels can trigger Alzheimer's dementia, it could also be used as a biomarker to aid early diagnosis and treatment."