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Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients

Adverse reactions and non-response are common in patients treated with thiopurine drugs. Current monitoring of drug metabolite levels for guiding treatment are limited to analysis of thioguanine nucleotides (TGNs) in erythrocytes after chemical derivatisation. Erythrocytes are not the target tissue...

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Autores principales: Coulthard, Sally A., Berry, Phil, McGarrity, Sarah, Ansari, Azhar, Redfern, Christopher P.F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4955110/
https://www.ncbi.nlm.nih.gov/pubmed/27362994
http://dx.doi.org/10.1016/j.jchromb.2016.06.017
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author Coulthard, Sally A.
Berry, Phil
McGarrity, Sarah
Ansari, Azhar
Redfern, Christopher P.F.
author_facet Coulthard, Sally A.
Berry, Phil
McGarrity, Sarah
Ansari, Azhar
Redfern, Christopher P.F.
author_sort Coulthard, Sally A.
collection PubMed
description Adverse reactions and non-response are common in patients treated with thiopurine drugs. Current monitoring of drug metabolite levels for guiding treatment are limited to analysis of thioguanine nucleotides (TGNs) in erythrocytes after chemical derivatisation. Erythrocytes are not the target tissue and TGN levels show poor correlations with clinical response. We have developed a sensitive assay to quantify deoxythioguanosine (dTG) without derivatisation in the DNA of nucleated blood cells. Using liquid chromatography and detection by tandem mass spectrometry, an intra- and inter-assay variability below 7.8% and 17.0% respectively were achieved. The assay had a detection limit of 0.0003125 ng (1.1 femtomoles) dTG and was quantified in DNA samples relative to endogenous deoxyadenosine (dA) in a small group of 20 patients with inflammatory bowel disease, all of whom had been established on azathioprine (AZA) therapy for more than 25 weeks. These patients had dTG levels of 20–1360 mol dTG/10(6) mol dA; three patients who had not started therapy had no detectable dTG. This method, comparable to previous methods in sensitivity, enables the direct detection of a cytotoxic thiopurine metabolite without derivatisation in an easily obtainable, stable sample and will facilitate a better understanding of the mechanisms of action of these inexpensive yet effective drugs.
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spelling pubmed-49551102016-08-15 Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients Coulthard, Sally A. Berry, Phil McGarrity, Sarah Ansari, Azhar Redfern, Christopher P.F. J Chromatogr B Analyt Technol Biomed Life Sci Short Communication Adverse reactions and non-response are common in patients treated with thiopurine drugs. Current monitoring of drug metabolite levels for guiding treatment are limited to analysis of thioguanine nucleotides (TGNs) in erythrocytes after chemical derivatisation. Erythrocytes are not the target tissue and TGN levels show poor correlations with clinical response. We have developed a sensitive assay to quantify deoxythioguanosine (dTG) without derivatisation in the DNA of nucleated blood cells. Using liquid chromatography and detection by tandem mass spectrometry, an intra- and inter-assay variability below 7.8% and 17.0% respectively were achieved. The assay had a detection limit of 0.0003125 ng (1.1 femtomoles) dTG and was quantified in DNA samples relative to endogenous deoxyadenosine (dA) in a small group of 20 patients with inflammatory bowel disease, all of whom had been established on azathioprine (AZA) therapy for more than 25 weeks. These patients had dTG levels of 20–1360 mol dTG/10(6) mol dA; three patients who had not started therapy had no detectable dTG. This method, comparable to previous methods in sensitivity, enables the direct detection of a cytotoxic thiopurine metabolite without derivatisation in an easily obtainable, stable sample and will facilitate a better understanding of the mechanisms of action of these inexpensive yet effective drugs. Elsevier 2016-08-15 /pmc/articles/PMC4955110/ /pubmed/27362994 http://dx.doi.org/10.1016/j.jchromb.2016.06.017 Text en © 2016 The Authors http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Short Communication
Coulthard, Sally A.
Berry, Phil
McGarrity, Sarah
Ansari, Azhar
Redfern, Christopher P.F.
Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title_full Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title_fullStr Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title_full_unstemmed Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title_short Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients
title_sort liquid chromatography–mass spectrometry for measuring deoxythioguanosine in dna from thiopurine-treated patients
topic Short Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4955110/
https://www.ncbi.nlm.nih.gov/pubmed/27362994
http://dx.doi.org/10.1016/j.jchromb.2016.06.017
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