A new study in laboratory rats shows that the statin drugs, which patients take to lower cholesterol levels, prompt growth cells to build new bone, replacing bone that has been leached away by osteoporosis.
The study will appear Friday in the journal Science.
Although the bone-building use of statins has not been tested in humans, a retrospective study of osteoporosis patients who also took the drugs shows evidence that their bones became more dense than did bones of osteoporosis patients who did not take the drug.
A team led by Dr. Greg Mundy, an endocrinologist at the University of Texas Health Science Center in San Antonio, found the potential new use for the statin drugs after screening more than 30,000 compounds for possible bone-strengthening effects.
"The statin discovery came out of the blue," said Mundy. "We did not expect it."
Mundy said the drug works by encouraging production of BMP2, an enzyme that prompts bones to grow new cells. There also is some evidence that the drug reduces the number of osteoclasts, the cells that reduce bone density.
When tested on laboratory rats, the statin drugs doubled the density of bones in the leg and spine.
Mundy said the drug also was tested on rats that had been surgically altered to develop bone loss in the same way that elderly women do. After treatment with the statin drugs, the bones strengthened, increasing in volume by up to 96 percent compared to altered rats not taking the drug, he said.
Dr. Sundeep Khosla, an osteoporosis researcher at the Mayo Clinic in Rochester, Minn., said Mundy's research "offers a lot of promise."
Khosla said some drugs will slow bone erosion in osteoporosis but the statins could be the first to actually restore bone that has been lost to the disease.
"It is a very intriguing discovery and really unexpected," said Khosla. He cautioned, however, that the work needs to be verified by other researchers and that it will be tricky to find the proper dose that safely prompts the bone-strengthening effect in humans.
More than 10 million Americans have been diagnosed with osteoporosis. The disorder most commonly strikes women after the age of menopause. It causes bones to lose density and become brittle. Fractures of the hip, vertebrae and other bones are very common, crippling and painful for osteoporosis sufferers.
The statin drugs used in the rat experiments were lovastatin, marketed under the brand name Mevacor, and simvastatin, sold under the brand name Zocor. Both are made by Merck & Co. Inc. of Whitehouse Station, N.J.
Mundy also is founder of a San Antonio company called OsteoScreen which is conducting osteoporosis research. He said the company could benefit financially if hs statin discovery is validated and becomes a standard of care.
Science, which published the study, is a peer-reviewed journal. All research in the journal is evaluated critically by independent, anonymous experts before it is accepted for publication.