Liver-on-chip model and application in predictive genotoxicity and mutagenicity of drugs.

Currently, there is no test system, whether in vitro or in vivo, capable of examining all endpoints required for genotoxicity evaluation used in pre-clinical drug safety assessment. The objective of this study was to develop a model which could assess all the required endpoints and possesses robust human metabolic activity, that could be used in a streamlined, animal-free manner. Liver-on-chip (LOC) models have intrinsic human metabolic activity that mimics the in vivo environment, making it a preferred test system. For our assay, the LOC was assembled using primary human hepatocytes or HepaRG cells, in a MPS-T12 plate, maintained under microfluidic flow conditions using the PhysioMimix® Microphysiological System (MPS), and co-cultured with human lymphoblastoid (TK6) cells in transwells. This system allows for interaction between two compartments and for the analysis of three different genotoxic endpoints, i.e. DNA strand breaks (comet assay) in hepatocytes, chromosome loss or damage (micronucleus assay) and mutation (Duplex Sequencing) in TK6 cells. Both compartments were treated at 0, 24 and 45 h with two direct genotoxicants: methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS), and two genotoxicants requiring metabolic activation: benzo[a]pyrene (B[a]P) and cyclophosphamide (CP). Assessment of cytochrome activity, RNA expression, albumin, urea and lactate dehydrogenase production, demonstrated functional metabolic capacities. Genotoxicity responses were observed for all endpoints with MMS and EMS. Increases in the micronucleus and mutations (MF) frequencies were also observed with CP, and %Tail DNA with B[a]P, indicating the metabolic competency of the test system. CP did not exhibit an increase in the %Tail DNA, which is in line with in vivo data. However, B[a]P did not exhibit an increase in the % micronucleus and MF, which might require an optimization of the test system. In conclusion, this proof-of-principle experiment suggests that LOC-MPS technology is a promising tool for in vitro hazard identification genotoxicants.

Complementary and alternative medicines use by Scottish women with breast cancer. What, why and the potential for drug interactions?

BACKGROUND: Despite the increased use of complementary and alternative medicine (CAM) by breast cancer patients, there is little published information regarding CAM use in the Scottish breast cancer population. METHODS: A questionnaire comprising five sections--demographics; perceived health status, prescribed medicines; use, indications, satisfaction and expenditure on CAMs; attitudes towards and factors associated with CAM use; and attitudinal statements--was issued to patients attending the Aberdeen Breast Clinic. RESULTS: A total of 453 questionnaires were distributed and 360 (79.5%) returned. Respondents were prescribed a mean of 3.2 medicines (95% CI 2.83-3.47). With regard to CAM use, 33.1% of respondents reported current use, 36.4% prior use, and 30.6% reported never having used CAMs. The key indications for use were general well being, boosting immune system and cancer prophylaxis, with high levels of satisfaction reported. The strongest association for CAM use was use by friends and family and higher educational attainment (p < 0.001). Supplements with estrogenic activity, such as soya or red clover, were taken by 29% of respondents. Herbs (echinacea, pomegranate, peppermint, chamomile, grapefruit, garlic, ginseng) that have the potential to interact with adjuvant endocrine therapies (tamoxifen, anastrazole, letrozole, exemestane) were being taken by 38% of treated patients. CONCLUSION: The level of CAM use by Scottish breast cancer patients is similar to that reported from other countries, although there are marked differences in the type, nature and frequency of specific CAM therapies. Higher patient education level and use by family and friends were significantly associated with CAM use. The high level of use of potentially disease modifying or interacting herb supplements may be of concern.