Factors affecting overall care experience for people living with rare conditions in the UK: exploratory analysis of a quantitative patient experience survey.

BACKGROUND: Although individually rare, collectively, rare conditions are common and affect a large number of people and are often chronic, life threatening and affect multiple body systems; the majority of them have no effective treatment. The literature has identified many specific challenges for those living with rare conditions, however, we do not know which of these in combination are most likely to impact how someone rates their overall experience of care. The aim of this study is to do further exploratory analysis of the Genetic Alliance UK 2020 Rare Experience survey data to identify which variables are most strongly associated with respondents' overall care experience. RESULTS: There were strong associations between most of the selected survey variables and the overall rated experience of care variable. In the multiple linear regression only nine variables remained in the best fit model: 'Trust and confidence in hospital staff involved in ongoing care'; 'Satisfaction with information provided by healthcare professionals-following diagnosis'; 'The professionals providing care work as a team'; 'Feel care is coordinated effectively'; 'The timing and frequency of appointments are convenient for the patient/carer/family'; 'Whether or not there is a specific healthcare professional to ask questions of about the rare/undiagnosed condition'; 'Experience of searching for a diagnosis'; 'Knowledge of whether there is a specialist centre for the condition'; and 'Number of different clinics attend for the condition'. CONCLUSIONS: Our findings indicate the challenges that play the largest part in explaining the varied experiences with rare disease healthcare in the UK for our survey respondents. These challenges should be further investigated with a broader sample of people affected by rare conditions, ideally through the implementation of a comprehensive national rare condition patient registry. Our findings highlight an important potential gap in the Framework, 'trust and confidence in healthcare professionals'; further research is required to fully understand the foundations of trust and confidence.

Giving Voice to Clinical Study Participants: Development and Deployment of Sequential Patient Experience Surveys for Global Clinical Studies.

BACKGROUND: Biopharmaceutical companies are piloting patient experience surveys (PES) to help enhance patient satisfaction with clinical studies. However, most PES have been conducted at study close-out, which can hinder recall and responsiveness, and at a limited number of sites, which restricts their applicability to global studies. Our aim was to investigate the feasibility of developing sequential PES, which would be deployed globally, and to provide practical recommendations based on our real-world experience. METHODS: To develop sequential PES (introductory, interim, close-out), we customized a previously developed patient experience close-out survey. Extensive input was gained from multiple stakeholders (e.g., survey experts, patient advisors, psychometricians, clinical trialists, lawyers). To deploy the PES in global studies, we prepared PES-specific ethics committee submissions, training materials (e.g., slides, videos), and PES invitation aids (postcards, digital app reminders). RESULTS: Developing and deploying sequential PES in global clinical studies was feasible. The 3-part online PES (25 to 37 questions per survey) passed health literacy testing. To facilitate benchmarking, the PES included core questions (including a Net Promoter Score question). The PES gained ethics approval and was deployed globally in 2017-2018 in 12 phase 2 and 3 clinical studies in North America, Europe, and the Asia-Pacific. Based on the real-world insights gained and the challenges encountered, we have made recommendations for PES. CONCLUSIONS: Our practical recommendations on the development and deployment of sequential global PES may assist others to implement PES efficiently and effectively, allowing them to gain feedback from patients globally during clinical studies.

Value of Developing Plain Language Summaries of Scientific and Clinical Articles: A Survey of Patients and Physicians.

BACKGROUND: We sought to determine the value and feasibility of developing plain language summaries (PLS) of peer-reviewed articles for patients. METHODS: Members of the European Patients Academy on Therapeutic Innovation or UCB Pharma (N = 74) with a diagnosis of chronic disease, as well as a group of randomly selected neurologists in the US (N = 90) participated in online surveys. Two physicians, 5 patients, and 1 caregiver participated in interviews. RESULTS: Patient survey and interview participants reported that they routinely sought health-related information online. Articles in scientific journals were ranked the third most important source in the survey (47%), after general Internet searches (61%) and patient-specific websites (57%). Survey physicians were equivocal in their views; 46% rated PLS as valuable, 46% as neutral, and 8% as not valuable; however, 60% reported they would use them. A predominant theme emerging in patient interviews was the importance of knowledge and the sense of empowerment it engenders. Patients viewed PLS as tools to facilitate knowledge sharing and making important information accessible. In interviews, physicians noted the value of PLS in generating dialogue, saving time and streamlining communication with patients, as patients are not completely dependent on them for information. CONCLUSION: Our results indicate PLS could play an important role in the patient-physician dialogue. Although patients in this study tended to be more informed and engaged than the general patient population, with continued expansion of online platforms and open-access publishing, it is likely that greater numbers of patients will seek more specialized health-related information in the future.

Antagonistic and synergistic interactions during the binding of binary mixtures of polycyclic aromatic hydrocarbons to the aryl hydrocarbon receptor.

In order to assess the potential of polycyclic aromatic hydrocarbons (PAHs) to interact with each other, benzo(a)pyrene (B(a)P) was incubated either alone or in combination with other isomeric 5-ring PAHs in precision-cut rat liver slices. At the end of the incubation, the slices were removed and the O-deethylation of ethoxyresorufin (EROD) was determined in microsomal preparations. The BP-mediated rise in EROD activity was suppressed in the presence of dibenzo(a,j)anthracene, dibenzo(a,c)anthracene and picene, whereas it was increased in the presence of pentacene. In the case of benzo(b)chrysene, benzo(c)chrysene and benzo(g)chrysene the effect was concentration-dependent with both antagonism and synergism being observed. The binding of B(a)P to the aryl hydrocarbon (Ah) receptor was similarly modulated by other PAHs. No correlation was evident between binding avidity of the PAH to the Ah receptor and either its potential for interaction or nature of interaction, e.g. synergism or antagonism. These interactions were also independent of the molecular shape (ring arrangement) of the 5-ring isomeric PAHs. Bearing in mind the role of the Ah receptor in chemical carcinogenesis, it may be concluded that interactions at the Ah receptor site may contribute to the well-established modulation of the carcinogenicity of one PAH in the presence of another.

Making Patient Engagement a Reality.

Patients are increasingly recognised as the true customers of healthcare. By providing insights and perspectives, patients can help the wider healthcare community better understand their needs and ultimately enhance the value of healthcare solutions being developed. In the development of new medicines, for example, meaningful patient engagement can enable the pharmaceutical industry, healthcare providers and other stakeholders to achieve more meaningful health outcomes. While both the pharmaceutical industry and regulators have achieved some progress in incorporating patient perspectives into their activities, the lack of standardised best practices and metrics has made it challenging to achieve consistency and measure success in patient engagement. Practical guidance for patient engagement can facilitate better interactions between patients or patient groups and other collaborators, e.g. industry, regulators and other healthcare stakeholders. Accordingly, UCB has developed an internal model for Patient Group Engagement incorporating four key principles, based on shared ambition, transparency, accountability and respect, essential for effective collaborations.

Up-regulation of CYP1A1 and phase II enzymes by 5-ring isomeric polycyclic aromatic hydrocarbons in precision-cut rat hepatic slices: Importance of molecular shape.

The objectives of the present study were two-fold: (a) to evaluate the role of molecular shape on the interaction of polycyclic aromatic hydrocarbons (PAHs) with the Ah receptor and CYP1A1 upregulation, and (b) to evaluate the potential of PAHs to induce epoxide hydrolase and glutathione S-transferase, two major enzymes involved in their metabolism. In order to achieve these objectives, precision-cut rat liver slices were incubated with a range of concentrations of seven 5-ring isomeric PAHs, namely benzo[c]chrysene, benzo[b]chrysene, benzo[g]chrysene, dibenzo[a,j]anthracene, dibenzo[a,c]anthracene, picene and pentacene, for 24h. All compounds, with the exception of pentacene, elevated the O-deethylation of ethoxyresorufin, an activity associated with CYP1A1; induction of this enzyme by the various PAHs correlated with their avidity for the Ah receptor. None of the PAHs studied increased epoxide hydrolase activity, monitored using benzo[a]pyrene 4,5-oxide. Of the seven PAHs, only benzo[g]chrysene elevated glutathione S-transferase activity, measured using 1-chloro-2,4-dinitrobenzene or 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole as substrates. No relationship could be established between length or length/width and interaction with the Ah receptor and CYP1A1 up-regulation indicating that other structural or electronic factors are likely to be more important. Finally, 5-ring PAHs are poor inducers of the epoxide hydrolase and glutathione S-transferase enzyme systems.

Synergistic and antagonistic interactions of binary mixtures of polycyclic aromatic hydrocarbons in the upregulation of CYP1 activity and mRNA levels in precision-cut rat liver slices.

The current studies investigate whether synergistic or antagonistic interactions in the upregulation of CYP1 activity occur in binary mixtures of polycyclic aromatic hydrocarbons (PAHs) involving benzo[a]pyrene and five other structurally diverse PAHs of varying carcinogenic activity. Precision-cut rat liver slices were incubated with benzo[a]pyrene alone or in combination with a range of concentrations of a second PAH, and ethoxyresorufin O-deethylase, CYP1A1 and CYP1B1 mRNA levels determined. Concurrent incubation of benzo[a]pyrene with either dibenzo[a,h]anthracene or fluoranthene in liver slices led to a synergistic interaction, at least at low concentrations, in that ethoxyresorufin O-deethylase activity was statistically higher than the added effects when the slices were incubated with the individual compounds. In contrast, benzo[b]fluoranthene and, at high doses only, dibenzo[a,l]pyrene gave rise to antagonism, whereas 1-methylphenanthrene had no effect at all concentrations studied. When CYP1A1 mRNA levels were monitored, benzo[b]fluoranthene gave rise to an antagonistic response when incubated with benzo[a]pyrene, whereas all other compounds displayed synergism, with 1-methylphenathrene being the least effective. A similar picture emerged when CYP1B1 mRNA levels were determined, though the effects were less pronounced. In conclusion, it has been demonstrated that the benzo[a]pyrene-mediated upregulation of CYP1, at the mRNA and activity levels, is synergistically and antagonistically modulated by other PAHs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 764-775, 2017.

Family planning and pregnancy issues for women with systemic inflammatory diseases: patient and physician perspectives.

OBJECTIVES: To identify family planning and pregnancy (FPP) issues for female patients of childbearing age living with a chronic inflammatory disease and to assess whether current clinical practice routinely provides adequate support to alleviate these concerns. SETTING: Multinational survey and an analysis of online patient activity. PARTICIPANTS: Premenopausal women (aged 20-45 years; N=969) were surveyed in the USA, the UK, Germany, France, Italy and Spain. Rheumatologists were surveyed in Germany (N=50), France (N=50), Italy (N=50) and the USA (N=100), and gastroenterologists were also surveyed in the USA (N=100). PRIMARY AND SECONDARY OUTCOME MEASURES: Two online surveys were undertaken to identify FPP issues for physicians and patients. The surveys examined the frequency of dialogue on these topics between physicians and patients, alongside assessment of patient satisfaction regarding these conversations. Online analysis identified key themes for patient discussion outside their doctors' office/clinic/surgery. RESULTS: 32-56% of physicians spontaneously reported having talked about FPP with their female patients of childbearing age. When prompted, the majority of rheumatologists (74-92%) and gastroenterologists (74%) reported having discussed conception/pregnancy with female patients; however, less than half reported consulting their patient's treating general practitioner/gynaecologist about these topics. The majority of patients reported their FPP-related concerns are not adequately addressed/settled during their medical appointments. Furthermore, only 30-40% of patients considered advice/information to be consistent across multiple healthcare professionals. Key online FPP-related patient discussions included disease state, adverse effects, treatment, switch behaviour and wash-out requirements. CONCLUSIONS: Female patients who live with chronic inflammatory disease have important FPP concerns. The majority of patients, however, do not feel that their FPP concerns are adequately addressed in current clinical practice and report that they receive inconsistent advice from the various healthcare professionals who manage different aspects of their care. There is a clear need for provision of up-to-date and consistent information/support to female patients.

The substantial burden of systemic lupus erythematosus on the productivity and careers of patients: a European patient-driven online survey.

OBJECTIVE: The objective of this study was to explore the burden of SLE and its effect on patients' lives. METHODS: The Lupus European Online (LEO) survey included patient-designed questions on demographics, SLE diagnosis, and the impact of SLE on careers. Three SLE-specific patient-reported outcome (PRO) questionnaires were also completed: the Lupus Quality of Life (LupusQoL), the Fatigue Severity Scale (FSS), and the Work Productivity and Activity Impairment (WPAI)-Lupus v2.0. The survey was available online in five languages from May through August 2010. All self-identified SLE participants were eligible to respond. Survey results were analysed using descriptive statistics. Multivariate linear regression explored factors contributing to impaired productivity. RESULTS: Of the 2070 European SLE patients completing the survey, 93.1% were women, 86.7% were aged <50 years and 71.8% had a college or university education. More than two-thirds of respondents (69.5%) reported that SLE affected their careers; 27.7% changed careers within a year of diagnosis. All LupusQoL domains (score range 0-100) were impaired, with fatigue (median domain score 43.8) being the most affected and intimate relationships (median domain score 75.0) the least. Most patients (82.5%) reported fatigue (FSS score ≥4). Productivity was impaired across all WPAI domains, both at work and in general activities. Fatigue, an inability to plan and reduced physical health were significantly associated with impaired productivity. Patients whose careers were affected by SLE had worse health-related quality of life, more fatigue and worse productivity than patients whose careers were not affected. CONCLUSION: LEO survey respondents reported that SLE negatively affects their daily lives, productivity and career choices.

Safety data and beneficial effects of the combined oral contraceptive ethinylestradiol 0.03 mg/chlormadinone acetate 2 mg (Belara®): a 13-cycle, observational study in routine clinical practice.

BACKGROUND: The monophasic hormonal combined oral contraceptive (COC) ethinylestradiol (EE) 0.03 mg/chlormadinone acetate (CMA) 2 mg (Belara®) has been shown to have good long-term efficacy and tolerability. OBJECTIVES: The aim of this study was to corroborate the long-term safety of EE 0.03 mg/CMA 2 mg by evaluating the incidence and severity of adverse drug reactions (ADRs) and cycle control over 13 treatment cycles. Additionally, the influence of EE 0.03 mg/CMA 2 mg on dysmenorrhoea, acne and the well-being of subjects was also investigated. METHODS: This observational study was conducted in Spain, France and Italy from April 2006 to August 2008. Subjects of reproductive age, without contraindications mentioned in the current summary of product characteristics, were prescribed EE 0.03 mg/CMA 2 mg in routine clinical practice. RESULTS: 3771 subjects were analysed and at least one ADR was reported in 833 (22.1%) subjects, with the majority of ADRs (75.6%) being judged as mild or moderate. The most frequently reported ADRs were intermenstrual bleeding (7.7% of all analysed subjects), headache (5.1%) and breast pain (2.7%). Spotting and breakthrough bleeding (defined as slight and heavier intermenstrual bleeding) at baseline were reported by 677 (18.0%) and 268 (7.1%) subjects, but were less frequent in cycles 10-13 (9.6% and 1.7%, respectively). Before study start, 61.8% of subjects suffered from dysmenorrhea, with the intensity being moderate or severe in 66.9% of these subjects. In cycles 10-13, the corresponding values were noted in 15.0% and 25.6% of subjects. The proportion of subjects who suffered from acne decreased from 46.5% at study entry to 14.9% after 13 medication cycles. More than 50% of the subjects who had switched from another oral contraceptive (OC) pill stated that the tolerability of EE 0.03 mg/CMA 2 mg and their health-related well-being were much better or better after two cycles of EE 0.03 mg/CMA 2 mg than when they were taking their previous OC, and about 85% of the subjects assessed the tolerability of EE 0.03 mg/CMA 2 mg as very good or good during the study. CONCLUSION: These results re-affirmed the favourable ADR profile of the COC EE 0.03 mg/CMA 2 mg, as well as its good cycle control and beneficial effects on dysmenorrhoea, complaints typically occurring during the cycle, acne and well-being.

Interactions between polycyclic aromatic hydrocarbons in binary mixtures: effects on gene expression and DNA adduct formation in precision-cut rat liver slices.

Although exposure to polycyclic aromatic hydrocarbons (PAHs) occurs mostly through mixtures, hazard and risk assessment are mostly based on the effects caused by individual compounds. The objective of the current study was to investigate whether interactions between PAHs occur, focusing on gene expression (as measured by cDNA microarrays) and DNA adduct formation. The effects of benzo[a]pyrene or dibenzo[a,h]anthracene (DB[a,h]A) alone and in binary mixtures with another PAH (DB[a,h]A, benzo[b]fluoranthene, fluoranthene or dibenzo[a,l]pyrene) were investigated using precision-cut rat liver slices. All compounds significantly modulated the expression of several genes, but overlap between genes affected by the mixture and by the individual compounds was relatively small. All mixtures showed an antagonistic response on total gene expression profiles. Moreover, at the level of individual genes, mostly antagonism was evident, with additivity and synergism observed for only a few genes. As far as DNA adduct formation is concerned, the binary mixtures generally caused antagonism. The effects in liver slices suggest a lower carcinogenic potency of PAH mixtures than estimated based on additivity of individual compounds.

Up-regulation of the glutathione S-transferase system in human liver by polycyclic aromatic hydrocarbons; comparison with rat liver and lung.

The cytosolic glutathione S-transferases (GSTs) comprise a pivotal enzyme system protecting the cell from electrophilic compounds. It plays a major role in the detoxication of the primary and dihydrodiol epoxides of polycyclic aromatic hydrocarbons (PAHs), so that modulation of this enzyme system by PAHs will impact on their carcinogenic activity. The potential of six structurally diverse PAHs, namely benzo[a]pyrene (B[a]P), fluoranthene, benzo[b]fluoranthene (B[b]F), dibenzo[a,l]pyrene, dibenzo[a,h]anthracene (D[a,h]A) and 1-methhylphenanthrene, to modulate hepatic GST activity was investigated in human precision-cut slices and compared to rat slices, a species frequently used in long-term carcinogenicity studies; changes were monitored at the activity, using three different substrates, protein and mRNA levels. When activity was monitored using the alpha-class selective 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, B[b]F was the only PAH that caused an increase in activity, which was accompanied by a rise in the Ya immunoreacting band. In rat slices, in addition to B[b]F, B[a]P and D[a,h]A also enhanced activity, being paralleled with increased levels of the Ya immunoreacting band. In the rat, all PAHs elevated mRNA levels. In both human and rat liver slices, only B[b]F enhanced activity when 1-chloro-2,4-dinitrobenzene (CDNB) served as substrate. To investigate tissue differences, similar studies were undertaken in precision-cut rat lung slices, incubated with PAHs under identical conditions, using CDNB, as this was the only substrate for which activity could be detected; none of the PAHs studied stimulated activity. It is concluded that some PAHs have the potential to induce GST activity in human liver tissue and that species and tissue differences exist in the induction of this enzyme system in the rat. However, the extent of induction of GST activity is very modest compared with the effect these compounds have on CYP1 expression, the family responsible for their bioactivation, and it is unlikely to compensate for the enhanced production of reactive intermediates.

Differential response of human and rat epoxide hydrolase to polycyclic aromatic hydrocarbon exposure: studies using precision-cut tissue slices.

The potential of polycyclic aromatic hydrocarbons (PAHs) to modulate microsomal epoxide hydrolase activity, determined using benzo[a]pyrene 5-oxide as substrate, in human liver, was evaluated and compared to rat liver. Precision-cut liver slices prepared from fresh human liver were incubated with six structurally diverse PAHs, at a range of concentrations, for 24h. Of the six PAHs studied, benzo[a]pyrene, dibenzo[a,h]anthracene and fluoranthene gave rise to a statistically significant increase in epoxide hydrolase activity, which was accompanied by a concomitant increase in epoxide hydrolase protein levels determined by immunoblotting. The other PAHs studied, namely dibenzo[a,l]pyrene, benzo[b]fluoranthene and 1-methylphenanthrene, influenced neither activity nor enzyme protein levels. When rat slices were incubated under identical conditions, only benzo[a]pyrene and dibenzo[a,h]anthracene elevated epoxide hydrolase activity, which was, once again accompanied by a rise in protein levels. At the mRNA level, however, all six PAHs caused an increase, albeit to different extent. In rat, epoxide hydroxylase activity in lung slices was much lower than in liver slices. In lung slices, epoxide hydrolase activity was elevated following exposure to benzo[a]pyrene and dibenzo[a,l]pyrene and, to a lesser extent, 1-methylphenanthrene; similar observations were made at the protein level. At both activity and protein levels extent of induction was far more pronounced in the lung compared with the liver. It is concluded that epoxide hydrolase activity is an inducible enzyme by PAHs, in both human and rat liver, but induction potential by individual PAHs varies enormously, depending on the nature of the compound involved. Marked tissue differences in the nature of PAHs stimulating activity in rat lung and liver were noted. Although in the rat basal lung epoxide hydrolase activity is much lower than liver, it is more markedly inducible by PAHs.

Up-regulation of CYP1A/B in rat lung and liver, and human liver precision-cut slices by a series of polycyclic aromatic hydrocarbons; association with the Ah locus and importance of molecular size.

Exposure of precision-cut rat liver slices to six structurally diverse polycyclic aromatic hydrocarbons, namely benzo[a]pyrene, benzo[b]fluoranthene, dibenzo[a,h]anthracene, dibenzo[a,l]pyrene, fluoranthene and 1-methylphenanthrene, led to induction of ethoxyresorufin O-deethylase, CYP1A apoprotein and CYP1A1 mRNA levels, but to a markedly different extent. In liver slices, constitutive CYP1A1 mRNA levels were higher, as well as being markedly more inducible by PAHs, compared with CYP1B1, a similar profile to that observed in human liver slices following exposure to the PAHs. Increase in ethoxyresorufin O-deethylase and in CYP1A1 apoprotein levels was also observed when precision-cut rat lung slices were incubated with the same PAHs, the order of induction potency being similar to that observed in liver slices. Under the same conditions of exposure, CYP1B1 apoprotein levels were elevated in the lung. Up-regulation of CYP1A1 by the six PAHs correlated with their affinity for the Ah receptor, determined using the chemical-activated luciferase expression (CALUX) assay. It may be concluded that (a) precision-cut liver and lung slices may be used to assess the CYP1 induction potential of chemicals at the activity, apoprotein and mRNA levels; (b) rat is a promising surrogate animal for human in studies to evaluate CYP1 induction potential; (c) CYP1A1 is far more inducible than CYP1B1 in both rat liver and lung; (d) CYP1 up-regulation by PAHs is related to their affinity for the Ah receptor, and finally (e) computer analysis revealed that the ratio of molecular length/width is an important determinant of CYP1 induction potency among equiplanar PAHs.

Modulation of gene expression and DNA-adduct formation in precision-cut liver slices exposed to polycyclic aromatic hydrocarbons of different carcinogenic potency.

Polycyclic aromatic hydrocarbons (PAHs) differ markedly in their carcinogenic potencies. Differences in transcriptomic responses upon PAH exposures might improve our current understanding of the differences in carcinogenicity, and therefore gene expression modulation by six PAHs in precision-cut rat liver slices was investigated. Gene expression modulation by benzo[a]pyrene (B[a]P), dibenzo[a,l]pyrene (DB[a,l]P), benzo[b]fluoranthene (B[b]F), fluoranthene (FA), dibenzo[a,h]anthracene (DB[a,h]A) and 1-methylphenanthrene (1-MPA) was assessed after 6- (B[a]P, DB[a,l]P) and 24-h (all compounds) exposure, using oligonucleotide arrays. DNA-adduct formation was determined using (32)P-post-labelling. The effects of PAHs on gene expression and on DNA-adduct formation were much more pronounced after 24-h exposure than after a 6-h exposure. Each compound induced gene expression changes dose-dependently and gene expression profiles were generally compound-specific. B[a]P, B[b]F and DB[a,h]A displayed comparable gene expression profiles, and so did DB[a,l]P, FA and 1-MPA. Only the carcinogenic PAHs (B[a]P, B[b]F, DB[a,l]P and DB[a,h]A) induced the oxidative stress pathway. DNA-adduct levels were: DB[a,l]P >> B[a]P > B[b]F > or = DB[a,h]A > FA > or = 1-MPA. The expression of only a few genes was found to correlate significantly with DNA-adduct formation, carcinogenic potency or Ah-receptor binding capacity (the last two taken from literature). These genes differed between the parameters. Our results indicate that PAHs generally induce a compound-specific response on gene expression and that discrimination of carcinogenic from non-carcinogenic compounds is partly feasible using this approach. Only at a specific pathway level, namely oxidative stress response, PAHs with high and low carcinogenic potency could be discriminated.

Evaluation of the precision-cut liver and lung slice systems for the study of induction of CYP1, epoxide hydrolase and glutathione S-transferase activities.

The principal objective was to ascertain whether precision-cut tissue slices can be used to evaluate the potential of chemicals to induce CYP1, epoxide hydrolase and glutathione S-transferase activities, all being important enzymes involved in the metabolism of polycyclic aromatic hydrocarbons. Precision-cut rat liver and lung slices were incubated with a range of benzo[a]pyrene concentrations for various time periods. A rise in the O-deethylation of ethoxyresorufin was seen in both liver and lung slices exposed to benzo[a]pyrene, which was accompanied by increased CYP1A apoprotein levels. Pulmonary CYP1B1 apoprotein levels and hepatic mRNA levels were similarly enhanced. Elevated epoxide hydrolase and glutathione S-transferase activities were also observed in liver slices following incubation for 24h; similarly, a rise in apoprotein levels of both enzymes was evident, peak levels occurring at the same time point. When mRNA levels were monitored, a rise in the levels of both enzymes was seen as early as 4h after incubation, but maximum levels were attained at 24 h. In lung slices, induction of epoxide hydrolase by benzo[a]pyrene was observed after a 24-h incubation, and at a concentration of 1 microM; a rise in apoprotein levels was seen at this time point. Glutathione S-transferase activity was not inducible in lung slices by benzo[a]pyrene but a modest increase was observed in hepatic slices. Collectively, these studies confirmed CYP1A induction in rat liver slices and established that CYP1B1 expression, and epoxide hydrolase and glutathione S-transferase activities are inducible in precision-cut tissue slices.