Profiling of Drug-Metabolizing Enzymes and Transporters in Human Tissue Biopsy Samples: A Review of the Literature

Within the drug pharmacokinetics (PK)-absorption, distribution, metabolism, and excretion (ADME) research community, investigators regularly generate in vitro data sets using appropriately vendor-sourced and processed human tissue. Such data enable drug screening, the generation of kinetic parameters, extrapolation of in vitro to in vivo, as well as the modeling and simulation of drug PK. Although there are large numbers of manuscripts describing studies with deceased organ donor tissue, relatively few investigators have published studies utilizing living donor tissue biopsy samples. After a review of the available literature, it was possible to find publications describing the use of tissue biopsy samples to determine enzyme inhibition ex vivo, the study of genotype-phenotype associations, the evaluation of tissue expression profiling following an inducer, and assessment of correlations between tissue expression profiles and in vivo-derived trait measures (e.g., biomarker plasma levels and probe drug PK). Some reports described multiple single-tissue biopsies, whereas others described singlemultiple-organ biopsies. It is concluded that biopsy-derived data can support modeling exercises (as input data and when validating models) and enable the assessment of organ-specific changes in enzyme and transporter profiles resulting from drug interactions, disease (e.g., metabolic disease, fibrosis, inflammation, cancer, infection), age, pregnancy, organ impairment, and genotype. With the emergence of multiorgan axes (e.g., microbiome-gut-liver-kidney) and interest in remote sensing (interorgan communication), it is envisioned that there will be increased demand for single- and multiorgan tissue biopsy data to support hypothesis testing and PK-ADME model building. SIGNIFICANCE STATEMENT Based on a review of the literature, it is apparent that profiling of human tissue biopsy samples is useful in support of pharmacokinetics (PK)-absorption, distribution, metabolism, and excretion (ADME)-related studies. With conventional tissue biopsy as precedent, it is envisioned that researchers will turn to less invasive "liquid biopsy" methods in support of ADME-related studies (e.g., profiling of plasma-derived tissue-specific nanovesicles). Generation of such multiorgan liquid biopsy data in larger numbers of subjects and at multiple study time points will provide a rich data set for modeling purposes.