Bone loading and mouse lifespan study, Digi Mart USA News: A recently published study suggests that bones release proteins that protect other tissues when squeezed, offering a new explanation for how exercise may benefit people as they age. The research was published in Cell Metabolism and was led by scientists at Southern Medical University in Guangzhou, China.
The team focused on osteocytes, bone cells that detect mechanical forces and use a pressure-sensitive channel called PIEZO1 to help bones adapt to physical exertion. The researchers found that PIEZO1 levels declined over time in both mouse and human bone.
Chemically destroying the channel in adult mouse osteocytes accelerated signs of aging in the brain, liver and muscles, reducing median lifespan by roughly 11% in females and 13% in males.
To test whether pressure on the skeleton could counter these effects, the researchers used a device to rhythmically apply a tiny load to the shinbones of anaesthetized mice, beginning when the animals were 20 months old. According to the study, the treated mice lived longer, with median lifespan extended by an average of 9.4%, or around 80 days.
Treated animals also showed improved blood sugar regulation, better bone structure, reduced markers of inflammation and senescence in several organs, and changes to the aging immune system.
Transferring plasma from treated mice to other old mice also delivered benefits, suggesting that something circulating in the blood contributed to the improvement. One candidate messenger was pigment epithelium-derived factor, or PEDF, a protein with protective effects in multiple tissues.
Bone loading increased its circulating levels, and injections of the protein reduced several signs of aging and improved cognitive and physical performance in older mice.
The researchers acknowledged that they have not established whether PEDF is essential to the effects of the loading treatment, and other proteins, immune changes or signaling pathways could also play a role. The study did not test whether bone loading extends human life.
Blood levels of PEDF are known to fall with age, and the protein has protected laboratory-grown human cartilage from experimentally induced damage, but the findings do not show that boosting PEDF keeps people younger.
The study adds to evidence that staying physically active may support healthy aging, though it does not show that a bone-squeezing treatment can replace walking, swimming or strength training in humans. Further research would be needed before any of these findings could be applied to people.
