5-HYDROXYTRYPTAMINE AND SKELETON STATUS.

Introduction. 5-hydroxytryptamin (serotonin) represents a monoamine with different functions. Central neurotransmitter is related to mood, food and energy regulation and indirect positive effects on bone mass via leptin and sympathetic system. Gut-derived 5-hydroxytryptamine directly influences the skeleton through Wnt/Lrp5/beta catenin signalling with opposite actions to the central pool. Method. This is a mini-review regarding serotonin- related bone changes. Results and discussions. All the bone cells have receptors for 5-hydroxytryptamine while skeleton may have an intrinsic ability to locally generate it. The monoamine displays paracrine and autocrine actions, some incompletely described. One practical point is the potential bone loss in clinical situations with serotonin excess as seen in carcinoid syndrome. Up to this moment, non-bone metastatic neuroendocrine tumours are not listed as cause of secondary osteoporosis. Another practical aspect is the use of circulating 5-hydroxytryptamine as bone turnover marker surrogate for assessing the future fragility fracture probability. Despite some correlations with classical bone remodelling markers, no clear cut conclusion has been established yet. Conclusion. 5-hydroxytryptamine displays complex effects on skeleton status, whether direct, indirect or local but there are data still unknown thus future need to connect the dots in this particular inter-disciplinary field. [ABSTRACT FROM AUTHOR]