The mythical “Fountain of Youth” isn’t in some far-off land; it’s flowing beat-by-beat inside every single young person. Young blood, it turns out, contains special healing properties that seem to fade away as we get older. Scientists in a new study showed that old mouse bones healed faster after a fracture when they were enriched with fresh blood from a young mouse. The findings indicate that, rather than old bones themselves being the problem, fractures in the elderly could be addressed by targeting blood proteins.
Old Becomes New
To test the effects of young blood, scientists surgically linked the circulatory systems of young mice and old mice together through a procedure known as parabiosis. They also paired mice of the same age together as a control. Then they fractured the shinbones of both mice once they were paired, to observe the way they healed. Fractured bones healed faster and more effectively in old mice paired with younger mice than in old mice paired with another old mouse. Conversely, young mice that received old blood had a diminished ability to repair fractures. Scientists noted that older bones contain higher levels of a protein called beta-catenin. This protein seems to encourage bone marrow to manufacture cells that hold bone together, rather than cells that actually produce bone. Beta-catenin levels were much lower in old mouse bones nourished by young blood. Therefore, scientists believe young blood cells must secrete a molecule that regulates beta-catenin levels, letting bones heal better and faster. They published their findings this week in the journal Nature Communications.
Still a Mystery
Scientists still aren’t sure what specific molecule secreted by blood cells is responsible for promoting healthier bone healing in young mice. The mystery gets even deeper when you consider the mounting evidence that young blood contains healing properties. Young blood has been shown to reverse heart degradation, recharge old brains and reverse muscle atrophy. Pinpointing the molecular compounds behind youthful blood’s healing magic could fuel development of drugs that encourage old bodies to behave like youngsters. By capturing the essence of youth in our blood, scientists may ultimately prove that age really is just a number.
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