New hope for Osteoporosis

95% of the body’s serotonin is produced in the gut, yet this form of serotonin is barred by a membrane from entering the brain, where the chemical plays an important role in the central nervous system as a neurotransmitter. Serotonin’s role outside the brain has long been a mystery to scientists, but researchers recently discovered that serotonin may play a critical role in the formation of new bone. Researchers discovered the serotonin-bone density link from two genetic diseases, caused by a mutation of the gene LRP5. In one mutation, patients have such weak bones that they cannot walk on their own, while patients with the opposite mutation have such dense bones that it s difficult to extract teeth from their jawbones. After further investigation, researchers discovered that LRP5 acts on serotonin-producing cells in the gut, blocking an enzyme that converts the amino acid tryptophan to serotonin. Higher levels of gut-produced serotonin released in the blood stream inhibit bone formation, while lower levels allow greater formation of new bone. Researchers are now working to apply these findings to find a new treatment for osteoporosis. Patients with osteoporosis have accelerated bone loss, now a lack of bone formation, so they generally have normal serotonin levels. Experts believe the key to a new osteoporosis treatment lies in developing a drug that will suppress serotonin production in the gut, allowing more bone formation to occur.