title: Determination of free serotonin and its metabolite 5-HIAA in blood human samples with consideration to pre-analytical factors.
abstract: Significant differences have been reported over the years in measuring physiological levels of free circulating serotonin (f5-HT) in platelet-poor plasma (PPP). This work shows that there are crucial pre-analytical factors in sample manipulation that can provoke an artifactual release of 5-HT from platelets, and that, even when the sample is accurately processed to obtain PPP, f5-HT levels are approximately 2.8 times higher than those of f5-HT in blood. An alternative methodology consisting of ex vivo blood microdialysis coupled to high-performance liquid chromatography-electrochemical detection is proposed and validated. It is considered the most accurate technique to measure physiological circulating f5-HT and its metabolite 5-hydroxyindoleacetic acid (f5-HIAA), owing to its sensitivity (limits of quantification of 0.08 ng/mL) and reliability since there is no sample manipulation. The f5-HT and f5-HIAA levels in blood and in PPP were studied in control subjects, hypertensive and end-stage renal disease patients, who have a deregulated serotonergic system. This work reveals that blood is the best matrix to determine f5-HT concentrations, and the clinical relevance of the accuracy of f5-HT determination is discussed.
authors.affiliation: Universitat Pompeu Fabra (CEXS-UPF), Barcelona, Spain; Human Pharmacology and Clinical Neurosciences Research Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research Institute, Barcelona, Spain.
authors.forename: Samanta
authors.initials: S
authors.lastname: Yubero-Lahoz
authors.forename: Joan
authors.initials: J
authors.lastname: Rodríguez
authors.forename: Anna
authors.initials: A
authors.lastname: Faura
authors.forename: Julio
authors.initials: J
authors.lastname: Pascual
authors.forename: Anna
authors.initials: A
authors.lastname: Oliveras
authors.forename: Higini
authors.initials: H
authors.lastname: Cao
authors.forename: Magí
authors.initials: M
authors.lastname: Farré
authors.forename: Rafael
authors.initials: R
authors.lastname: de la Torre
mesh_terms: D001792:Blood Platelets; D001800:Blood Specimen Collection; D002498:Centrifugation; D002851:Chromatography, High Pressure Liquid; D006493:Heparin; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000097:blood* / Q000737:chemistry; D006973:Hypertension / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood; D017551:Microdialysis; D015203:Reproducibility of Results; D012701:Serotonin / Q000097:blood* / Q000737:chemistry
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006493:Heparin
keywords: blood; microdialysis; platelet; platelet-poor plasma; serotonin