Men's Osteoporosis Support GroupSerotonin and BMD; Osteoporosis Issues update for vitamin D; and fasting CTX and risk of osteonecrosis of the jaws Nat Med. 2010 Feb 7. [Epub ahead of print]. Pharmacological inhibition of gut-derived serotonin synthesis is a potential bone anabolic treatment for osteoporosis. Yadav VK and others. PMID: 20139991. This study, using ovariectomized rodents, was a test of a proof of principle that blocking the formation of gut-derived serotonin (GDS) could have an anabolic (increase) in bone formation effect. They used a small molecule that blocked the synthesis of tryptophan hydroxylase-1, which is an enzyme in GDS biosynthesis. The result was a positive effect on bone formation. Editor's comments. This is a preliminary study, and in rodents only, but if the results prove to apply to humans, this could be an effective way to build bone mineral density (BMD). It is my understanding that preliminary trials are being conducted on humans. I'd not heard of serotonin blockage being in anyway related to BMD before seeing these results. We normally think of serotonin regarding its function in brain biochemistry, but it obviously has additional effects. Apparently there is no deleterious effect from blocking GDS on brain serotonin levels. Or at least nothing that has been elucidated yet. I'll be watching for future updates from human studies to see if this turns out to be a safe and effective means of treating osteoporosis. Osteoporosis Issues has been updated with a new article on vitamin D. As I'm sure you know, vitamin D is very important in bone formation, mainly functioning to promote absorption of calcium from the gut. But it has also been shown to be implicated in many other areas, including preventing or slowing several cancers, including, colon, breast, prostate and several other types. Additionally it appears to be important in M.S., diabetes, autoimmune diseases, etc. Thus I hope you will read the article and have your serum vitamin D level tested and then work to keep it in the normal range of at least 30 ng/mL and up to 90 mg/mL, or slightly higher. Implant Dent. 2010 Feb;19(1):29-38. CTX Biochemical Marker of Bone Metabolism. Is It a Reliable Predictor of Bisphosphonate-Associated Osteonecrosis of the Jaws After Surgery? Part II: A Prospective Clinical Study. Lee CY, Suzuki JB. PMID: 20147814. This was a study to test the validity of serum cross-linked C-telopeptide of type I collagen (CTX), which is a marker of osteoclast activity, as a risk factor for osteonecrosis of the jaws (ONJ) in patients taking bisphosphonates. It involved 163 consecutive patients taking oral bisphosphonates and who were to have oral surgical procedures. A group of 109 patients did not have CTX tests before oral surgery and 54 did have it. None of the patients developed ONJ 8 weeks and beyond the treatment. The authors stated, "We conclude that the serum CTX is not a valid preoperative test to accurately assess the level of risk of developing ONJ and is not indicated in the oral surgery patient." Editor's comments. In a previous Update I reviewed an article where the authors found the fasting morning CTX was helpful in determining when it was safe to do oral surgery on patients taking oral bisphosphonates. The Lee and Suzuki study contradicts those results, showing no difference if a CTX was done or was not done--no one developed ONJ after oral surgery. So for now there appears to be no 100% effective test to determine who will or won't develop ONJ if oral surgery is done. With the mean age of 75.9 years of the participants in the Lee and Suzuki study, and none developing ONJ, this is reassuring that ONJ doesn't appear to be a high risk from having oral surgery if you are taking oral bisphosphonates. Hopefully more studies will follow to clear up exactly what is the risk, and what will reduce it as much as possible.
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