In vitro models that capture the complexity of in vivo tissue and organ behaviors in a scalable and easy-to-use format are desirable for drug discovery. To address this, we have developed a bioreactor that fosters maintenance of 3D tissue cultures under constant perfusion and we have integrated multiple bioreactors into an array in a multiwell plate format. All bioreactors are fluidically isolated from each other. Each bioreactor in the array contains a scaffold that supports formation of hundreds of 3D microscale tissue units. The tissue units are perfused with cell culture medium circulated within the bioreactor by integrated pneumatic diaphragm micropumps. Electronic controls for the pumps are kept outside the incubator and connected to the perfused multiwell by pneumatic lines. The docking design and open-well bioreactor layout make handling perfused multiwell plates similar to using standard multiwell tissue culture plates. A model of oxygen consumption and transport in the circulating culture medium was used to predict appropriate operating parameters for primary liver cultures. Oxygen concentrations at key locations in the system were then measured as a function of flow rate and time after initiation of culture to determine oxygen consumption rates. After seven days in culture, tissue formed from cells seeded in the perfused multiwell reactor remained functionally viable as assessed by immunostaining for hepatocyte and liver sinusoidal endothelial cell (LSEC) phenotypic markers.

are employees of Genentech, Inc, a member of the Roche group, and own Roche stock. C. E. Brightling is a consultant with fees paid to his institution from Genentech, Inc, and Regeneron; received research grants and was a consultant with fees paid to his institution from AstraZeneca, GlaxoSmithKline, Sanofi, Boehringer Ingelheim, Roche/Genentech, Chiesi, 4D Pharma, Mologics, and Novartis.Background: The IL-33/ST2 pathway is linked with asthma susceptibility. Inhaled allergens, pollutants, and respiratory viruses, which trigger asthma exacerbations, induce release of IL-33, an epithelial-derived ''alarmin.'' Astegolimab, a human IgG 2 mAb, selectively inhibits the IL-33 receptor, ST2. Approved biologic therapies for severe asthma mainly benefit patients with elevated blood eosinophils (type 2-high), but limited options are available for patients with low blood eosinophils (type 2-low). Inhibiting IL-33 signaling may target pathogenic pathways in a wider spectrum of asthmatics. Objectives: This study evaluated astegolimab efficacy and safety in patients with severe asthma. Methods: This double-blind, placebo-controlled, dose-ranging study (ZENYATTA [A Study to Assess the Efficacy and Safety of MSTT1041A in Participants With Uncontrolled Severe Asthma]) randomized 502 adults with severe asthma to subcutaneous placebo or 70-mg, 210-mg, or 490-mg doses of astegolimab every 4 weeks. The primary endpoint was the annualized asthma exacerbation rate (AER) at week 54. Enrollment caps ensured 30 patients who were eosinophil-high (> _300 cells/mL) and 95 patients who were eosinophil-low (<300 cells/mL) per arm. Results: Overall, adjusted AER reductions relative to placebo were 43% (P 5 .005), 22% (P 5 .18), and 37% (P 5 .01) for 490mg, 210-mg, and 70-mg doses of astegolimab, respectively. Adjusted AER reductions for patients who were eosinophil-low were comparable to reductions in the overall population: 54% (P 5 .002), 14% (P 5 .48), and 35% (P 5 .05) for 490-mg, 210mg, and 70-mg doses of astegolimab. Adverse events were similar in astegolimab-and placebo-treated groups. Conclusions: Astegolimab reduced AER in a broad population of patients, including those who were eosinophil-low, with inadequately controlled, severe asthma. Astegolimab was safe and well tolerated. (J Allergy Clin Immunol 2021;nnn:nnnnnn.)

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Assessment of drug–liver interactions is an integral part of predicting the safety profile of new drugs. Existing model systems range from in vitro cell culture models to FDA-mandated animal tests. Data from these models often fail, however, to predict human liver toxicity, resulting in costly failures of clinical trials. In vitro screens based on cultured hepatocytes are now commonly used in early stages of development, but many toxic responses in vivo seem to be mediated by a complex interplay among several different cell types. We discuss some of the evolving trends in liver cell culture systems applied to drug safety assessment and describe an experimental model that captures complex liver physiology through incorporation of heterotypic cell–cell interactions, 3D architecture and perfused flow. We demonstrate how heterotypic interactions in this system can be manipulated to recreate an inflammatory environment and apply the model to test compounds that potentially exhibit idiosyncratic drug toxicity. Finally, we provide a perspective on how the range of existing and emerging in vitro liver culture approaches, from simple to complex, might serve needs across the range of stages in drug discovery and development, including applications in molecular therapeutics.

Dash A, Simmers MB, Deering TG, Berry DJ, Feaver RE, Hastings NE, Pruett TL, LeCluyse EL, Blackman BR, Wamhoff BR. Hemodynamic flow improves rat hepatocyte morphology, function, and metabolic activity in vitro. Am J Physiol Cell Physiol 304: C1053-C1063, 2013. First published March 13. 2013 doi:10.1152/ajpcell.00331.2012.-In vitro primary hepatocyte systems typically elicit drug induction and toxicity responses at concentrations much higher than corresponding in vivo or clinical plasma Cmax levels, contributing to poor in vitro-in vivo correlations. This may be partly due to the absence of physiological parameters that maintain metabolic phenotype in vivo. We hypothesized that restoring hemodynamics and media transport would improve hepatocyte architecture and metabolic function in vitro compared with nonflow cultures. Rat hepatocytes were cultured for 2 wk either in nonflow collagen gel sandwiches with 48-h media changes or under controlled hemodynamics mimicking sinusoidal circulation within a perfused Transwell device. Phenotypic, functional, and metabolic parameters were assessed at multiple times. Hepatocytes in the devices exhibited polarized morphology, retention of differentiation markers [E-cadherin and hepatocyte nuclear factor-4␣ (HNF-4␣)], the canalicular transporter [multidrug-resistant protein-2 (Mrp-2)], and significantly higher levels of liver function compared with nonflow cultures over 2 wk (albumin ϳ4-fold and urea ϳ5-fold). Gene expression of cytochrome P450 (CYP) enzymes was significantly higher (fold increase over nonflow: CYP1A1: 53.5 Ϯ 10.3; CYP1A2: 64.0 Ϯ 15.1; CYP2B1: 15.2 Ϯ 2.9; CYP2B2: 2.7 Ϯ 0.8; CYP3A2: 4.0 Ϯ 1.4) and translated to significantly higher basal enzyme activity (device vs. nonflow: CYP1A: 6.26 Ϯ 2.41 vs. 0.42 Ϯ 0.015; CYP1B: 3.47 Ϯ 1.66 vs. 0.4 Ϯ 0.09; CYP3A: 11.65 Ϯ 4.70 vs. 2.43 Ϯ 0.56) while retaining inducibility by 3-methylcholanthrene and dexamethasone (fold increase over DMSO: CYP1A ϭ 27.33 and CYP3A ϭ 4.94). These responses were observed at concentrations closer to plasma levels documented in vivo in rats. The retention of in vivo-like hepatocyte phenotype and metabolic function coupled with drug response at more physiological concentrations emphasizes the importance of restoring in vivo physiological transport parameters in vitro.hemodynamics; hepatocyte; metabolism; organotype; phenotype HEPATOTOXICITY AND BIOAVAILABILITY issues comprise over 60% of drug failures during clinical trials (45) and are a major cause of postmarketing withdrawal (23), pointing to the need to develop more efficient and predictive preclinical test systems. Simple cellular and subcellular assays used to screen compound libraries offer the advantage of higher throughput but are often unable to capture complex biological effects that may require a physiological context for drug interactions with cells. Primary in vitro hepatocyte models widely used to study liver disease, drug metabolism, and toxicity are extensively reviewed in the literature (16,42). The ability to test the metabolic f...