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Reconstituting Cytoarchitecture and Function of Human Epithelial Tissues on an Open-Top Organ-Chip

Nearly all human organs are lined with epithelial tissues, comprising one or multiple layers of tightly connected cells organized into three-dimensional ...

University of Cincinnati

Cincinnati Children's Hospital Medical Center

Successful translation of in vivo experimental data to human patients is an unmet need and a bottleneck in the development of effective therapeutics. Organ-on-Chip technology aims to address this need by leveraging recent significant advancements in microfabrication and biomaterials, which enable modeling of organs and their functionality. These microengineered chips offer researchers the possibility to recreate critical elements of native tissue architecture such as in vivo relevant tissue-tissue interface, air-liquid interface, and mechanical forces, including mechanical stretch and fluidic shear stress, which are crucial to recapitulate tissue level functions. Here, we present the development of a new, comprehensive 3D cell-culture system, where we combined our proprietary Organ-Chip technology with the advantages offered by three-dimensional organotypic culture. Leveraging microfabrication techniques, we engineered a flexible chip that consists of a chamber containing an organotypic epithelium, surrounded by two vacuum channels that can be actuated to stretch the hydrogel throughout its thickness. Furthermore, the ceiling of this chamber is a removable lid with a built-in microchannel that can be perfused with liquid or air and removed as needed for direct access to the tissue. The bottom part of this chamber is made from a porous flexible membrane which allows diffusive mass transport to and from the microfluidic channel positioned below the membrane. This additional microfluidic channel can be coated with endothelial cells to emulate a blood vessel and recapitulate endothelial interactions. Our results show that the Open-Top Chip design successfully addresses common challenges associated with the Organs-on-Chip technology, including the capability to incorporate a tissue-specific extracellular matrix gel seeded with primary stromal cells, to reproduce the architectural complexity of tissues by micropatterning the gel, and to extract the gel for H&E staining. We also provide proof-of-concept data on the feasibility of using the system with primary human skin and alveolar epithelial cells.

A novel organ-chip system emulates three-dimensional architecture of the human epithelia and the mechanical forces acting on it.

Traditional drug safety assessment often fails to predict complications in humans, especially when the drug targets the immune system. Here, we show the unprecedented capability of two human Organs-on-Chips to evaluate the safety profile of T-cell bispecific antibodies (TCBs) targeting tumor antigens. Although promising for cancer immunotherapy, TCBs are associated with an on-target, off-tumor risk due to low levels of expression of tumor antigens in healthy tissues. We leveraged in vivo target expression and toxicity data of TCBs targeting folate receptor 1 (FOLR1) or carcinoembryonic antigen (CEA) to design and validate human immunocompetent Organs-on-Chips safety platforms. We discovered that the Lung-Chip and Intestine-Chip could reproduce and predict target-dependent TCB safety liabilities, based on sensitivity to key determinants thereof, such as target expression and antibody affinity. These novel tools broaden the research options available for mechanistic understandings of engineered therapeutic antibodies and assessing safety in tissues susceptible to adverse events.

Human immunocompetent Organ-on-Chip platforms allow safety profiling of tumor-targeted T-cell bispecific antibodies.

For centuries, animal experiments have contributed much to our understanding of mechanisms of human disease, but their value in predicting the effectiveness of drug treatments in the clinic has remained controversial. Animal models, including genetically modified ones and experimentally induced pathologies, often do not accurately reflect disease in humans, and therefore do not predict with sufficient certainty what will happen in humans. Organ-on-chip (OOC) technology and bioengineered tissues have emerged as promising alternatives to traditional animal testing for a wide range of applications in biological defence, drug discovery and development, and precision medicine, offering a potential alternative. Recent technological breakthroughs in stem cell and organoid biology, OOC technology, and 3D bioprinting have all contributed to a tremendous progress in our ability to design, assemble and manufacture living organ biomimetic systems that more accurately reflect the structural and functional characteristics of human tissue in vitro, and enable improved predictions of human responses to drugs and environmental stimuli. Here, we provide a historical perspective on the evolution of the field of bioengineering, focusing on the most salient milestones that enabled control of internal and external cell microenvironment. We introduce the concepts of OOCs and Microphysiological systems (MPSs), review various chip designs and microfabrication methods used to construct OOCs, focusing on blood-brain barrier as an example, and discuss existing challenges and limitations. Finally, we provide an overview on emerging strategies for 3D bioprinting of MPSs and comment on the potential role of these devices in precision medicine.

Modelling Human Physiology on-Chip: Historical Perspectives and Future Directions.

The main objective of this study was to demonstrate that computational fluid dynamics (CFD) modeling can be used to study the contribution of covert and overt vascular architecture to the risk for cerebrovascular disease in sickle cell disease (SCD) and to determine the mechanisms of response to therapy such as chronic red blood cell (cRBC) transfusions. We analyzed baseline (screening), pre-randomization and study exit magnetic resonance angiogram (MRA) images from 10 (5 each from the transfusion and observation arms) pediatric sickle SCD participants in the silent cerebral infarct transfusion (SIT) trial using CFD modeling. We reconstructed the intracranial portion of the internal carotid artery and branches and extracted the geometry using 3D Slicer. We cut specific portions of the large intracranial artery to include segments of the internal carotid, middle, anterior, and posterior cerebral arteries such that the vessel segment analyzed extended from the intracranial beginning of the internal carotid artery up to immediately after (~0.25 inches) the middle cerebral artery branching point. Cut models were imported into Ansys 2021R2/2022R1 and laminar and time-dependent flow simulation was performed. Change in time averaged mean velocity, wall shear stress, and vessel tortuosity were compared between the observation and cRBC arms. We did not observe a correlation between time averaged mean velocity (TAMV) and mean transcranial Doppler (TCD) velocity at study entry. There was also no difference in change in time average mean velocity, wall shear stress (WSS), and vessel tortuosity between the observation and cRBC transfusion arms. WSS and TAMV were abnormal for 2 (developed TIA) out of the 3 participants (one participant had silent cerebral infarctions) that developed neurovascular outcomes. CFD approaches allow for the evaluation of vascular topology and hemodynamics in SCD using MRA images. In this proof of principle study, we show that CFD could be a useful tool and we intend to carry out future studies with a larger sample to enable more robust conclusions.

Barrile Riccardo

Department of Biomedical Engineering

University of Cincinnati

Reconstituting Cytoarchitecture and Function of Human Epithelial Tissues on an Open-Top Organ-Chip

Barrile Riccardo

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Biomedical Engineering

University of Cincinnati

Reconstituting Cytoarchitecture and Function of Human Epithelial Tissues on an Open-Top Organ-Chip

Department of Biomedical Engineering