FoodCAP: acid-labile protein adducts of heterocyclic amines in human blood are not viable biomarkers of HCA dietary exposure

Kevin Cooper, Geraldine Cuskelly, Sarah Brennan, Jayne Woodside, Marie Cantwell, Xiaoxiao Guo, Mark Mooney, Christopher Elliott

Research output: Contribution to conferencePosterpeer-review

Abstract

Intake of heterocyclic amines (HCAs, carcinogens produced during cooking of meat/fish, the most abundant being PhIP, DiMeIQx and MeIQx) is influenced by many factors including type/thickness of meat and cooking method/temperature/duration. Thus, assessment of HCA dietary exposure is difficult. Protein adducts of HCAs have been proposed as potential medium-term biomarkers of exposure, e.g. PhIP adducted to serum albumin or haemoglobin. However, evidence is still lacking that HCA adducts are viable biomarkers in humans consuming normal diets. The FoodCAP project, supported by World Cancer Research Fund, developed a highly sensitive mass spectrometric method for hydrolysis, extraction and detection of acid-labile HCAs in blood and assessed their validity as biomarkers of exposure. Multiple acid/alkaline hydrolysis conditions were assessed, followed by liquid-liquid extraction, clean-up by cation-exchange SPE and quantification by UPLC-ESI-MS/ MS. Blood was analysed from volunteers who completed food diaries to estimate HCA intake based on the US National Cancer Institute’s CHARRED database. Standard HCAs were recovered quantitatively from fortified blood. In addition, PhIP/MeIQx adducts bound to albumin and haemoglobin prepared in vitro using a human liver microsome system were also detectable in blood fortified at low ppt concentrations. However, except for one sample (5pg/ml PhIP), acid-labile PhIP, 7,8-DiMeIQx, 4,8-DiMeIQx and MeIQx were not observed above the 2pg/ml limit of detection in plasma (n=35), or in serum, whole blood or purified albumin, even in volunteers with high meat consumption (nominal HCA intake >2µg/day). It is concluded that HCA blood protein adducts are not viable biomarkers of exposure. Untargeted metabolomic analyses may facilitate discovery of suitable markers.
Original languageEnglish
Publication statusPublished - 10 Apr 2014
EventASSET 2014: Food Integrity and Traceability Conference - Queen's University Belfast, Belfast, United Kingdom
Duration: 08 Apr 201410 Apr 2014

Conference

ConferenceASSET 2014: Food Integrity and Traceability Conference
Country/TerritoryUnited Kingdom
CityBelfast
Period08/04/201410/04/2014

Bibliographical note

Poster 14

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