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Title: Identification of intelligent biomarkers of exposure in the respiratory epithelia to tobacco smoke components
Author: Sexton, Keith
ISNI:       0000 0004 2751 7464
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2008
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A novel toxicological tool, which consisted of a differentiated, 3-D, in vitro model of human respiratory epithelia, i.e. EpiAirway-100 cells (MatTek Corp., USA), was utilised to identify intelligent biomarkers in human respiratory epithelia following exposure to selected particle and vapour phase tobacco smoke components (TSC); thus providing a holistic approach towards the identification of biomarkers in the pulmonary epithelium. A range of TSC doses were used to elicit a classic dose response which was characterised by conventional toxicology techniques (transepithelial electrical resistance [TEER], cell viability [MTT] and protein assay). All four TSC appeared to induce similar stress responses (e.g. protective mechanisms) within the model. Histological (LM level) examination was utilised to investigate the morphological changes in cellular-tissue organisation in the ETM, following exposure challenges with the TSC. In conjunction with this, targeted immunohistochemistry assays were performed in order to better characterise the tissue response at the cellular level, i.e. basal, ciliated, intermediate and Goblet cells. Three discrete zones of tissue injury and repair were delineated: (1) the apical region, (2) the suprabasal region and (3) the basal zone (i.e. where basal cells acted as progenitors or stem cells). Toxicogenomics was carried out to identify early molecular markers for events in pulmonary injury. This study identified nine genes, with the potential of being genomic biomarkers, for specific disease mechanisms known to be associated with tobacco smoke. Another potential genomic biomarker was identified which was not previously related to tobacco smoke, PTGS1. Its induction could result in a disruption of tissue homeostasis that may lead to the onset of a number of human inflammatory diseases (e.g. chronic obstructive pulmonary disorder). The proteomic analysis identified two proteins (cystatin-A and ubiquitin) that were significantly induced for all TSC exposures and could be described as ‘defence proteins’. Consequently, they represented potential biomarkers of general lung injury. This study also identified three proteins (complement C3, calmodulin and CD9) that could be used as biomarkers for specific disease mechanisms (e.g. atherosclerosis).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QH301 Biology