A sensation was created in osteoporosis research circles recently (Nov 26 2008) when a report published in Cell revealed that serotonin made by the gut appears to control bone formation. Osteoporosis authorities expressed surprised at the development which the investigators hail as a breakthrough that could lead to a new and very different treatment. The preliminary research was conducted on mice that were engineered to have human genes.
Ninety-five percent of serotonin in the body is produced in the gut and only 5 percent in the brain. The discovery is linked to a gene called LRP5 which controls an enzyme that converts the amino acid tryptophan to serotonin in the gut. The new research indicates that high levels of gut serotonin inhibit bone growth, and lowered levels of serotonin make bone denser.
The serotonin link to bone strength was identified in children with a rare condition of very weak bones and in people with extremely dense jaw bones. These conditions were found to be due to mutations of the gene LRP5 which in turn either impaired or increased bone formation. The projection from the discovery is that a drug may be created that reduces serotonin production in the gut thereby stimulating bone growth.
As exciting as it sounds, the information may not alter what we know about age-related osteoporosis as the investigators found osteoporosis patients tend to have normal serotonin levels. And in the trial, animals with normal genes that were fed a tryptophan deficient diet didn’t grown denser bones. Time will tell whether this apparent ‘breakthrough’ will translate into a safe and effective new treatment. Read more…