Platelets or thrombocytes are involved in the body’s capability to form blood clots, essentially maintaining homeostasis. Platelets perform these functions by releasing a slew of chemicals and factors.

Recently three different teams of researchers, two from UCSF and one team from University of Queensland, Australia who were working on transfusing blood from younger patients, the longevity hormone klotho and exercise have identified PF4 (platelet factor 4) as a common entity in enhancing cognitive function.
The three different teams aimed at releasing their respective papers at the same time, to provide an encompassing view of the role of PF4.
Platelet Factor Lessens Brain Inflammation

The team found that certain substances in platelets can help the ageing brain when introduced through young blood. When older male mice were exposed to a part of young mice’s blood containing these substances, it reduced inflammation in the hippocampus area of the brain and improved cognition.
The team observed that a chemical called platelet factor 4 (PF4) was in higher amounts in young mice and humans compared to older ones. Giving older mice PF4 from outside also lowered brain inflammation, brought positive changes at the molecular level, and enhanced memory.
This seems to happen because PF4 decreases harmful immune factors and restores the older immune system, benefiting the ageing brain. We discovered that a receptor called CXCR3 plays a role in these benefits of PF4 on the ageing brain.
Exercise Improves Brain Health

Researchers have purported the role of exercise in improving brain health for years. Yet researchers have not identified many of these chemicals responsible for these positive effects.
The research team from Queensland showed that systemic plasma factor 4 released during exercise improved brain health by rejuvenating brain cells. PF4 was capable of stimulating stem cells to undergo division and differentiation, improving cognitive health.
Klotho and PF4 Improve Brain Function
Klotho is a protein that plays a significant role in several biological processes, including ageing, longevity, and cognition. Researchers injected klotho into mice and found that it increased concentrations of PF4.
Increased PF4 improved brain activity in younger mice and abated cognitive deficits in older mice, the study showed. Even without PF4, klotho still improved thinking, which means other things might help too.
Making platelet factors, which could be messengers from klotho, might make young brains think better and help older brains with thinking problems.
Future Benefits:
Further studies could open up new avenues for improving memory, learning, and overall cognitive abilities, both in young individuals and in those experiencing age-related cognitive decline.
The findings that PF4 can ameliorate age-related cognitive impairments suggest that targeting PF4 or related factors could provide a means to rejuvenate the ageing brain. This could have significant implications for improving the quality of life for older individuals.
The study’s findings could suggest ways to combine different treatments for maximum cognitive benefits. For instance, if klotho, exercise, and PF4 all contribute to cognitive improvement, understanding their interactions could lead to more effective interventions.