Southern Medical University: bone stimulation extended the lifespan of old mice by nearly 80 days
Gentle compression of the tibiae in old mice made osteocytes release the PEDF protein and slowed signs of aging. The lifespan effect has so far been seen only in mice.
Researchers at Southern Medical University in China report that bones influence the pace at which the whole organism ages, according to PoradnikZdrowie.pl, which describes a study published in Cell Metabolism. In old mice, mechanical stimulation of the bones slowed signs of aging and extended life by nearly 80 days compared with controls 
poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. The authors stress that the lifespan effect has so far been observed only in mice poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
PIEZO1 sensor in osteocytes
Osteocytes, the cells embedded in bone, detect mechanical load with the help of proteins such as PIEZO1. The team used genetic modification to block PIEZO1 production in the osteocytes of middle-aged mice, aged 10 months poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. After five months these animals showed more signs of aging than the control group: poorer memory, weaker motor coordination and lower physical fitness poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
Their brains, livers, bones and other organs contained more senescent cells and more inflammation, and their ability to regulate blood glucose worsened poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. Males without PIEZO1 in osteocytes lived 13.2% shorter and females 10.7% shorter than controls poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
Tibia compression and the PEDF protein
In the next stage, 20-month-old mice had their tibiae subjected to controlled, gentle compression twice a week for four months poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. Afterwards these animals scored better in memory, motor performance and muscle strength tests. They also had stronger bones, better glucose tolerance, fewer signs of aging in various organs and lower inflammation poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. They lived nearly 80 days longer than controls, regardless of sex poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
Mechanically stimulated osteocytes released signaling substances into the blood. One of them is PEDF, a protein known for anti-inflammatory and protective properties poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. Stimulation raised its concentration in the blood of mice, and intravenous PEDF given to old animals produced effects similar to those of bone loading poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. In the bone marrow of old mice, more immune cells typical of young animals appeared, and fewer cells that promote chronic inflammation poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
Preliminary analyses in humans showed that blood PEDF declines with age and is especially low in people with osteoporosis poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. In a model of human cartilage, PEDF limited signs of cell aging and protected the tissue from damage poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗. The authors hope the work will help develop methods for people who cannot exercise regularly, such as mechanical bone stimulation or PEDF-based therapy. Whether similar effects occur in humans is still unknown poradnikzdrowie.plPoradnikZdrowie.plporadnikzdrowie.plOpen source ↗.
