Park's research could bolster bone strength, prevent osteoporosis

Yeonhwa Park, assistant professor of Food Science, recently received a two-year, $407,000 grant from the National Center for Complementary and Alternative Medicine to improve osteoporosis prevention and treatment. She is testing a new compound that could boost the efficiency of dietary calcium and nudge marrow stem cells to form new bone, even in older adults, when taken as a supplement with calcium.

Osteoporosis is the disease of decreased bone mass that affects about 10 million people in the United States, 80 percent of them women, mostly after menopause. But it can also strike men and younger people with hormone imbalances or other risk factors. Bone loss raises the risk of breaks from low calcium mineral density and disrupted microarchitecture.

Campaigns to persuade millions of women to take calcium supplements have raised awareness and are a step in the right direction, Park says, but taking calcium by itself has limited effect. Her research has identified a food compound known as conjugated linoleic acid (CLA) that shows promise as an additive that might put calcium to work more efficiently and build stronger bones, especially in older people where it is needed the most. CLA was discovered in the 1980s in ruminant animals such as cows and sheep.

Among other things, CLA seems to regulate fat formation, Park explains, and in bone marrow, stem cells have the option to form either fat or bone cells. Further, it is known that in older animals bone marrow stem cells tend to favor fat cell formation at the expense of bone. But there’s some evidence that when more CLA is available in marrow, stem cells will opt to form more bone cells. If Park and colleagues can find a way to nudge stem cells to form a higher percentage of bone cells and not fat, the supplement might help prevent osteoporosis.

Park’s two-pronged study will test CLA plus calcium in a living animal model in mice and in a laboratory tissue model using mouse bone marrow stem cells. The two experiments will build on the food scientist’s earlier observation that when extra calcium is available in the diet plus CLA, total bone mass improves. With their new experiments, Park and colleagues will extend this knowledge to see whether CLA plus calcium supplement in the diet can slow bone loss in ovarectomized mice, that is, in animals forced into early menopause, which mimics old age.

At the same time, they’ll study bone marrow tissue to try to find a mechanism that can explain how CLA plus dietary calcium supplements might improve bone mass.

As with some other animal laboratory work, Park cautions, in this case the CLA plus calcium model for improving bone mass seems to be more robust in mice than in humans. Nevertheless, she is hopeful that by pinpointing the mechanism for enhanced bone formation in marrow stem cells and adding dietary CLA, she might devise a new preventive strategy for humans, to reduce the more than 2 million bone fractures per year estimated to be related to osteoporosis.

December 30, 2008.

E-mail story to a friendPrinter-friendly version

/more talking points/