
Originally Posted by
MasterShake
Anyone have any opinions on this article?
Why Steroids Weaken Bones
For years, doctors have known that steroids, such as cortisone, can leave bones weaker than they found them. Now they know why. The America Association for the Advancement of Science (AAAS) reports that scientists have long suspected that steroids interfere with the process of bone remodeling, in which cells called osteoclasts continuously break down old bone while other cells called osteoblasts build new bone. (Old bone must be broken down first, otherwise the new bone that is added will be of inferior quality.) Things got confusing, however, when studies with bone-building osteoblasts produced conflicting results. In animal models, scientists found that cortisone dismantles osteoblasts, suppressing bone formation. But studies in cell culture showed that the drug fuels bone growth. According to the AAAS report, Steven Teitelbaum, a bone cell biologist at Washington University School of Medicine in St. Louis, Missouri, developed a line of transgenic mice with modified osteoclasts: The cells still functioned normally, but they lacked steroid receptors. When the researchers gave high doses of cortisone to these mice, the mice built typically strong and healthy bones. Mice with normal osteoclasts, however, produced inferior bones when given high doses of cortisone.