Apical Medium Flow Influences the Morphology and Physiology of Human Proximal Tubular Cells in a Microphysiological System

Standalone cell culture microfluidic device-based microphysiological system for automated cell observation and application in nephrotoxicity tests

Microphysiological systems (MPS) offer an alternative method for culturing cells on microfluidic platforms to model organ functions in pharmaceutical and medical sciences. Although MPS hardware has been proposed to maintain physiological organ function through perfusion culture, no existing MPS can automatically assess cell morphology and conditions online to observe cellular dynamics in detail. Thus, with this study, we aimed to establish a practical strategy for automating cell observation and improving cell evaluation functions with low temporal resolution and throughput in MPS experiments. We developed a versatile standalone cell culture microfluidic device (SCCMD) that integrates microfluidic chips and their peripherals. This device is compliant with the ANSI/SLAS standards and has been seamlessly integrated into an existing automatic cell imaging system. This integration enables automatic cell observation with high temporal resolution in MPS experiments. Perfusion culture of human kidney proximal tubule epithelial cells using the SCCMD improves cell function. By combining the proximal tubule MPS with an existing cell imaging system, nephrotoxicity studies were successfully performed to automate morphological and material permeability evaluation. We believe that the concept of building the ANSI/SLAS-compliant-sized MPS device proposed herein and integrating it into an existing automatic cell imaging system for the online measurement of detailed cell dynamics information and improvement of throughput by automating observation operations is a novel potential research direction for MPS research.

The evolving role of investigative toxicology in the pharmaceutical industry

For decades, preclinical toxicology was essentially a descriptive discipline in which treatment-related effects were carefully reported and used as a basis to calculate safety margins for drug candidates. In recent years, however, technological advances have increasingly enabled researchers to gain insights into toxicity mechanisms, supporting greater understanding of species relevance and translatability to humans, prediction of safety events, mitigation of side effects and development of safety biomarkers. Consequently, investigative (or mechanistic) toxicology has been gaining momentum and is now a key capability in the pharmaceutical industry. Here, we provide an overview of the current status of the field using case studies and discuss the potential impact of ongoing technological developments, based on a survey of investigative toxicologists from 14 European-based medium-sized to large pharmaceutical companies.

Consideration of Commercially Available Hepatocytes as Cell Sources for Liver-Microphysiological Systems by Comparing Liver Characteristics

In recent years, microphysiological systems (MPS) have been developed to shorten the test period and reduce animal experiments for drug development. We examined cell sources for the liver-MPS, i.e., MPS mimicking liver function. For liver-MPS, liver-like cells with high liver functions are required. Cryo-preserved hepatocytes (cryoheps), the gold standard hepatocytes for in vitro drug development, present several disadvantages, including differences between lots due to individual donor variations or a limited cell supply from the same donor. As such, alternatives for cryoheps are sought. Hepatocyte-like cells derived from human induced pluripotent stem cells (hiPSC-Heps), hepatocytes derived from liver-humanized mice (PXB-cells), and human liver cancer cells (HepG2 cells) were examined as source candidates for liver-MPS. Gene expression levels of the major cytochrome P450 of hiPSC-Heps, PXB cells, and HepG2 cells were compared with 22 lots of cryoheps, and the activities of hiPSC-Heps were compared with 8 lots of cryopreserved hepatocytes. A focused DNA microarray was used for the global gene analysis of the liver-like characteristics of hiPSC-Heps, PXB-cells, cryoheps, and HepG2 cells. Gene expression data from the focused microarray were analyzed by principal component analysis, hierarchical clustering, and enrichment analysis. The results indicated the characteristics of individual hepatocyte cell source and raised their consideration points as an alternative cell source candidate for liver-MPS. The study contributes to the repetitive utilization of a robust in vitro hepatic assay system over long periods with stable functionality.