{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T04:17:06Z","timestamp":1790050626948,"version":"4.0.1"},"reference-count":35,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,9,1]],"date-time":"2022-09-01T00:00:00Z","timestamp":1661990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Research Projects of National Relevance (PRIN) 2017 funds (Italian Ministry of Education, University and Research\u2014MIUR)","award":["20173EAZ2Z"],"award-info":[{"award-number":["20173EAZ2Z"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>L-Tryptophan (TRP) metabolites and related biomarkers play crucial roles in physiological functions, and their imbalances are implicated in central nervous system pathologies and neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer\u2019s disease, Parkinson\u2019s disease, schizophrenia and depression. The measurement of TRP metabolites and related biomarkers possesses great potential to elucidate the disease mechanisms, aid preclinical drug development, highlight potential therapeutic targets and evaluate the outcomes of therapeutic interventions. An effective, straightforward, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS\/MS) method was developed for the simultaneous determination of 24 TRP-related compounds in miniaturised murine whole blood samples. Sampling and sample pretreatment miniaturisation were achieved thanks to the development of a volumetric dried blood microsampling approach. Volumetric absorptive microsampling (VAMS) allows the accurate sampling of microvolumes of blood with advantages including, but not limited to, minimal sampling invasiveness, logistical improvements, method sustainability in terms of solvents and energy consumption, and improvement of animal studies in the framework of the 3Rs (Replacement, Reduction and Refinement) principles on animal welfare. The VAMS-LC-MS\/MS method exhibited good selectivity, and correlation coefficient values for the calibration curves of each analyte were &gt;0.9987. The limits of quantitation ranged from 0.1 to 25 ng\/mL. The intra- and inter-day precisions in terms of RSD were &lt;9.6%. All analytes were stable in whole blood VAMS samples stored at room temperature for at least 30 days with analyte losses &lt; 14%. The developed method was successfully applied to the analysis of biological samples from mice, leading to the unambiguous determination of all the considered target analytes. This method can therefore be applied to analyse TRP metabolites and related biomarkers levels to monitor disease states, perform mechanistic studies and investigate the outcomes of therapeutic interventions.<\/jats:p>","DOI":"10.3390\/molecules27175652","type":"journal-article","created":{"date-parts":[[2022,9,2]],"date-time":"2022-09-02T00:19:01Z","timestamp":1662077941000},"page":"5652","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["Volumetric Absorptive Microsampling (VAMS) for Targeted LC-MS\/MS Determination of Tryptophan-Related Biomarkers"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9310-4957","authenticated-orcid":false,"given":"Michele","family":"Protti","sequence":"first","affiliation":[{"name":"Research Group of Pharmaco-Toxicological Analysis (PTA Lab), Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum\u2013University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Cirrincione","sequence":"additional","affiliation":[{"name":"Research Group of Pharmaco-Toxicological Analysis (PTA Lab), Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum\u2013University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9631-591X","authenticated-orcid":false,"given":"Roberto","family":"Mandrioli","sequence":"additional","affiliation":[{"name":"Department for Life Quality Studies (QuVi), Rimini Campus, Alma Mater Studiorum\u2013University of Bologna, Corso d\u2019Augusto 237, 47921 Rimini, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James","family":"Rudge","sequence":"additional","affiliation":[{"name":"Neoteryx LLC, 421 Amapola Ave, Torrance, CA 90501, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7199-7141","authenticated-orcid":false,"given":"Luca","family":"Regazzoni","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Milan, Via Mangiagalli 25, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valeria","family":"Valsecchi","sequence":"additional","affiliation":[{"name":"Department of Neuroscience and Reproductive and Odontostomatological Sciences, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3967-7954","authenticated-orcid":false,"given":"Claudia","family":"Volpi","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Perugia, Piazzale Gambuli 1, 06132 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0644-9461","authenticated-orcid":false,"given":"Laura","family":"Mercolini","sequence":"additional","affiliation":[{"name":"Research Group of Pharmaco-Toxicological Analysis (PTA Lab), Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum\u2013University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1007\/s00109-013-1046-9","article-title":"The causative role and therapeutic potential of the kynurenine pathway in neurodegenerative disease","volume":"91","author":"Amaral","year":"2013","journal-title":"J. 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