3D models as tools for inhaled drug development
Anthony J. Hickey, Heidi M. Mansour in Inhalation Aerosols, 2019
Many in vitro respiratory models of both cell lines and primary cells are cultured on cell insert systems that can facilitate the growth of epithelial cells at an air-liquid interface (ALI), better mimicking the lung environment (26,31), and ALI culture has been found to induce cell polarization, differentiation, and mucus production (6,18,32). These cell insert cultures are sometimes referred to as 3D cultures and can support co-culture of different cell types on opposite sides of a membrane. In modeling the respiratory tract, epithelial cells can be co-cultured with other cells from the relevant region, for example, immune cells, providing a better mimic of the in vivo environment (5,11,18,23) and can potentially provide improved physiological responses over monoculture systems in response to aerosolized particles (32). However, the cell insert membranes between the cells, generally composed of polycarbonate (PC) and polyethylene terephthalate (PET), although permeable, prevent formation of an integrated interface and prohibit full cellular cross-talk. Furthermore, while some regions of the respiratory epithelium constitute a monolayer, a single cell-type monolayer does not reflect the in vivo situation, limiting the physiological accuracy of results. Although these cell insert models are a valuable tool for drug transport studies (6), their simplicity means that they are not a reliable tool for investigating toxicity in depth because they lack a native immune response (32,33).
Current Concepts of Implantation and Decidualization
Gabor Huszar in The Physiology and Biochemistry of the Uterus in Pregnancy and Labor, 2020
The development of appropriate media and techniques allowed the in vitro culture of preimplantation and postimplantation embryos.91,92 The most extensive and advanced work has been done with the mouse, but later developments with other species promise the advantages of comparative study. Although there are analogies between in vivo and in vitro implantation, none of the in vitro systems developed to date faithfully reproduce the event as it occurs in vivo. However, in vitro cultures have contributed to the definition of the autonomous capabilities of the trophoblast developing outside the uterus and the maternal host. These in vitro methods provide better defined conditions than ectopic pregnancy. They also permit manipulative control, continuous observation, and in the case of coculture on cellular substrata, an evaluation of the role of cell-cell contact.
Recent in vitro Models for the Blood-Brain Barrier
Carla Vitorino, Andreia Jorge, Alberto Pais in Nanoparticles for Brain Drug Delivery, 2021
The use of endothelial cells alone or in combination with other components of the neurovascular units, in a controlled environment, is a frequently adopted strategy to yield a significant amount of data, with these models presenting a good reproducibility and high-throughput screening performance. To reproduce the physical barrier between the endothelial lumen and the brain tissue, cells are cultured over a microporous membrane, which separates the upper (luminal) compartment from the lower (abluminal) compartment. These are the Transwell models, the most common approach for BBB modelling. The simpler models rely on the use of endothelial cells over the membrane. However, these models do not take into consideration the communication between endothelial cells and other types of cells. A more trustworthy approach includes the co-culture of different types of cells, thus better reproducing the respective physiological interaction. While endothelial cells are cultured on the upper compartment, pericytes, astrocytes and/or neurons are cultured on the lower compartment [11].
A review of co-culture models to study the oral microenvironment and disease
Published in Journal of Oral Microbiology, 2020
Sophie E Mountcastle, Sophie C Cox, Rachel L Sammons, Sara Jabbari, Richard M Shelton, Sarah A Kuehne
Co-culture techniques allow a variety of cell types to be cultivated together, enabling examination of cell–cell interactions [10]. These systems may refer to the culture of two or more eukaryotic cell types together, or eukaryotic and prokaryotic cells. The effectiveness of co-cultures is heavily determined by the choice of experimental setup. Cell–cell interactions in co-cultures are strongly influenced by the extracellular environment, which in turn is influenced by the employed protocol [11]. There are numerous factors that need to be optimised to ensure these systems are representative of the native oral cavity, such as the number of cell populations. Having more than two species can result in unstable systems due to multiple reaction pathways, which may be difficult to monitor, analyse, and interpret [11].
Core/shell multicellular spheroids on chitosan as in vitro 3D coculture tumor models
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Ching-Wen Tsai, Jyh-Horng Wang, Tai-Horng Young
For a living organism, different kinds of cells are responsible for different functions and cooperate with each other to maintain the overall tissue function. Thus, it is impractical to predict cell behaviors in vivo by just considering the response of single type of cells in vitro. To this end, coculture techniques are extensively developed for specific studies recently. In addition to normal tissues, tumor is also considered to be a kind of tissue in a living organism and is composed of many kinds of cells such as cancer cells, cancer stem cells, mesenchymal stem cells, inflammatory cells, cancer-associated fibroblasts and endothelial cells [46,47]. Moreover, mesenchymal stem cells could promote the growth and angiogenesis of tumors [25], and cancer-associated fibroblasts could enhance the proliferation and decrease the drug sensitivity of cancer cells [26–28]. Figure 1 also shows that healthy 3A6 and Hs68 cocultured on the bottom chambers of the transwell could really enhance the viabilities of the doxorubicin-treated SW620 cells in the inserts. These data mean that mesenchymal stem cells and fibroblasts can mediate the nearby cancer cells, and the cancer cells can be stimulated by their microenvironment. Therefore, to figure out the interactions between the cell–cell and the cell–extracellular matrix (ECM) within the tumor tissue, coculture techniques play important roles on cancer-related studies.
The nanomaterial-induced bystander effects reprogrammed macrophage immune function and metabolic profile
Published in Nanotoxicology, 2020
Peng Yuan, Xiangang Hu, Qixing Zhou
Coculture method in vitro has been frequently used in many experiments to study bystander responses. In this approach, both targeted and non-targeted cells are either physically connected or are separated by a physical barrier (Bewicke-Copley et al. 2017; Ng et al. 2015; Verma and Tiku 2017). Transwell insert coculture system is a widely used no-physical contact coculture system to study bystander effects and its mediators in vitro (Bhabra et al. 2009; Ng et al. 2015; Sood et al. 2011). As human nonsmall cell lung cancer (NSCLC) cell line A549 and human monocyte THP-1 coculture represent a widely established in vitro lung cell culture model (Klein et al. 2013; Ventura et al. 2020), and pulmonary toxicity is one of the most important health concerns regarding nanomaterial exposure (Yuan, Zhou, and Hu 2020), in this study, a coculture system of A549 and THP-1 was used to mimic the lung microenvironment to study the bystander effects of WS2 nanosheets on microenvironment macrophages during the inhalation exposure or the nanomaterial application in the lung. The study may provide a perspective into the noncontact risks of nanomaterials.
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