aging

Nanoscopic tour of aging bone

bones

“If people think of bone at all—and they usually don’t, until they have a fracture—they think of it as an inert material,” says Ayyalusamy Ramamoorthy, professor of chemistry and of biophysics. “But like everything else, bone is also made up of molecules whose behavior is reflected in its structure, toughness, and mechanical strength, making bone really exciting in terms of its chemistry and its contribution to health and well-being.”

U. MICHIGAN (US)—Scientists are studying a noninvasive way to get inside our bones and learn more about how disease and aging might affect them.

A team from the University of Michigan has used a variation of solid-state nuclear magnetic resonance (NMR) spectroscopy called magic-angle spinning to view bone at the nanoscopic level. The technique makes solid material as amenable to analysis as solutions are. They report their findings in the Dec. 2 issue of the Journal of the American Chemical Society.

“If people think of bone at all—and they usually don’t, until they have a fracture—they think of it as an inert material,” says Ayyalusamy Ramamoorthy, professor of chemistry and of biophysics. “But like everything else, bone is also made up of molecules whose behavior is reflected in its structure, toughness, and mechanical strength, making bone really exciting in terms of its chemistry and its contribution to health and well-being.”

Previous NMR studies have used pulverized bone, but the Michigan group’s instruments and methods made it possible to analyze a sample of intact cow bone.

Ramamoorthy says NMR spectroscopy is the ideal tool to analyze what’s going on in side bone at nanoscopic resolution. “It is possible to probe the structure and dynamics of individual molecules that constitute bone without any physical damage or chemical modification.”

The cow bone sample that the team studied was shaped to fit the rotor that is spun at the so-called magic angle inside the probe of a solid-state NMR spectrometer. With this technique, the researchers examined changes that occur in bone with water loss.

The water content of bone tissue decreases with age, which—by affecting both collagen and minerals—reduces bone’s strength and toughness.

“We were able to see dynamical structural changes with the main protein, collagen,” Ramamoorthy explains. “Its characteristic triple helix structure was not completely damaged, but its mobility was altered, in addition to a disorder in the structure.”

The success of the study makes possible future research into how bone’s constituents behave under different conditions.

“We’d like to look at how bone changes at the atomic level, as a function of aging,” Ramamoorthy adds, “and to make comparisons between diseased and healthy bone.” Such studies may provide insights into the susceptibility of bone to fracture, especially in the osteoporotic tissues of many elderly people.

Funding for the work was provided by the National Institutes of Health, the National Science Foundation, and the Department of Defense.

University of Michigan news: www.umich.edu/news/

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