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Hyndman L, McKee S, McGinty S. Solute transport with Michaelis-Menten kinetics for in vitro cell culture. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2023; 40:49-72. [PMID: 36201433 DOI: 10.1093/imammb/dqac014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 03/14/2023]
Abstract
A traditional method of in vitro cell culture involves a monolayer of cells at the base of a petri dish filled with culture medium. While the primary role of the culture medium is to supply nutrients to the cells, drug or other solutes may be added, depending on the purpose of the experiment. Metabolism by cells of oxygen, nutrients and drug is typically governed by Michaelis-Menten (M-M) kinetics. In this paper, a mathematical model of solute transport with M-M kinetics is developed. Upon non-dimensionalization, the reaction/diffusion system is re-characterized in terms of Volterra integral equations, where a parameter $\beta $, the ratio of the initial solute concentration to the M-M constant, proves important: $\beta \ll 1$ is relevant to drug metabolism for the liver, whereas $\beta \gg 1$ is more appropriate in the case of oxygen metabolism. Regular perturbation expansions for both cases are obtained. A small-time expansion and steady-state solution are also presented. All results are compared against the numerical solution of the Volterra integral equations, and excellent agreement is found. The utility of the model and analytical solutions are discussed in the context of assisting experimental researchers to better understand the environment within in vitro cell culture experiments.
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Affiliation(s)
- Lauren Hyndman
- Division of Biomedical Engineering, University of Glasgow, Glasgow G12 8QQ, UK
| | - Sean McKee
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XQ, UK
| | - Sean McGinty
- Division of Biomedical Engineering, University of Glasgow, Glasgow G12 8QQ, UK
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2
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William N, Acker JP. Transient loss of membrane integrity following intracellular ice formation in dimethyl sulfoxide-treated hepatocyte and endothelial cell monolayers. Cryobiology 2020; 97:217-221. [PMID: 33031823 DOI: 10.1016/j.cryobiol.2020.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/14/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
Abstract
Immediate post-thaw evaluation of membrane integrity has proven to yield overestimates of cell survival under conditions that preclude intracellular ice formation (IIF). However, prominent theories on the mechanisms of intracellular nucleation suggest a damaged membrane can reseal, prompting us to evaluate whether immediate post-thaw assessments of membrane integrity can in fact underestimate cell survival under conditions that promote IIF. HUVEC and HepG2 monolayers were treated with 1.4 M DMSO and frozen to -25 °C under conditions that formed either 0% or 100% IIF. Membrane integrity was evaluated both immediately and 24 h post-thaw, with metabolic activity assessments performed 24 h post-thaw as a secondary measure of survival. Treatment with 1.4 M DMSO and nucleation of 100% IIF resulted in a drastic increase in the relative percent of membrane intact cells following a 24 h culture period (HUVEC: 90.2% ± 0.7%; HepG2: 70.4% ± 4.0%), which correlated with 24 h post-thaw metabolic activity. These differences between the immediate and 24 h post-thaw membrane integrity assessments were significantly more than those seen in the absence of either IIF or DMSO treatment. Therefore, a high incidence of IIF in DMSO-treated monolayers may lead to erroneous underestimates of cell survival when conducting immediate post-thaw assessments of membrane integrity.
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Affiliation(s)
- Nishaka William
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
| | - Jason P Acker
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, T6G 2R3, Canada; Centre for Innovation, Canadian Blood Services, 8249 114th Street, Edmonton, AB, T6G 2R8, Canada.
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3
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William N, Acker JP. Cryoprotectant-dependent control of intracellular ice recrystallization in hepatocytes using small molecule carbohydrate derivatives. Cryobiology 2020; 97:123-130. [PMID: 33007287 DOI: 10.1016/j.cryobiol.2020.09.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/17/2022]
Abstract
To promote the recovery of cells that undergo intracellular ice formation (IIF), it is imperative that the recrystallization of intracellular ice is minimized. Hepatocytes are more prone to IIF than most mammalian cells, and thus we assessed the ability of novel small molecule carbohydrate-based ice recrystallization inhibitors (IRIs) to permeate and function within hepatocytes. HepG2 monolayers were treated with N-(4-chlorophenyl)-d-gluconamide (IRI 1), N-(2-fluorophenyl)-d-gluconamide (IRI 2), or para-methoxyphenyl-β-D-glycoside (IRI 3) and fluorescent cryomicroscopy was used for real time visualization of intracellular ice recrystallization. Both IRI 2 and IRI 3 reduced rates of intracellular recrystallization, whereas IRI 1 did not. IRI 2 and IRI 3, however, demonstrated a marked reduction in efficiency in the presence of the most frequently used permeating cryoprotectants (CPAs): glycerol, propylene glycol (PG), dimethyl sulfoxide (DMSO), and ethylene glycol (EG). Nevertheless, IRI 3 reduced rates of intracellular recrystallization relative to CPA-only controls in the presence of glycerol, PG, and DMSO. Interestingly, IRI preparation in trehalose, a commonly used non-permeating CPA, did not impact the activity of IRI 3. However, trehalose did increase the activity of IRI 1 while decreasing that of IRI 2. While this study suggests that each of these compounds could prove relevant in hepatocyte cryopreservation protocols where IIF would be prominent, CPA-mediated modulation of intracellular IRI activity is apparent and warrants further investigation.
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Affiliation(s)
- Nishaka William
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
| | - Jason P Acker
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, T6G 2R3, Canada; Centre for Innovation, Canadian Blood Services, 8249 114th Street, Edmonton, AB, T6G 2R8, Canada.
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4
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Ehrlich A, Duche D, Ouedraogo G, Nahmias Y. Challenges and Opportunities in the Design of Liver-on-Chip Microdevices. Annu Rev Biomed Eng 2020; 21:219-239. [PMID: 31167098 DOI: 10.1146/annurev-bioeng-060418-052305] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The liver is the central hub of xenobiotic metabolism and consequently the organ most prone to cosmetic- and drug-induced toxicity. Failure to detect liver toxicity or to assess compound clearance during product development is a major cause of postmarketing product withdrawal, with disastrous clinical and financial consequences. While small animals are still the preferred model in drug development, the recent ban on animal use in the European Union created a pressing need to develop precise and efficient tools to detect human liver toxicity during cosmetic development. This article includes a brief review of liver development, organization, and function and focuses on the state of the art of long-term cell culture, including hepatocyte cell sources, heterotypic cell-cell interactions, oxygen demands, and culture medium formulation. Finally, the article reviews emerging liver-on-chip devices and discusses the advantages and pitfalls of individual designs. The goal of this review is to provide a framework to design liver-on-chip devices and criteria with which to evaluate this emerging technology.
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Affiliation(s)
- Avner Ehrlich
- Grass Center for Bioengineering, Benin School of Computer Science and Engineering, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Daniel Duche
- L'Oréal Research and Innovation, Aulnay-sous-Bois 93600, France
| | | | - Yaakov Nahmias
- Grass Center for Bioengineering, Benin School of Computer Science and Engineering, Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Tissue Dynamics Ltd., Jerusalem 91904, Israel
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5
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Leedale J, Colley HE, Gaskell H, Williams DP, Bearon RN, Chadwick AE, Murdoch C, Webb SD. In silico-guided optimisation of oxygen gradients in hepatic spheroids. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.comtox.2019.100093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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6
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Keeley TP, Mann GE. Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans. Physiol Rev 2019; 99:161-234. [PMID: 30354965 DOI: 10.1152/physrev.00041.2017] [Citation(s) in RCA: 183] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The extensive oxygen gradient between the air we breathe (Po2 ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognized that cell culture undertaken under room air conditions falls short of replicating this protection in vitro. Despite this, difficulty in accurately determining the appropriate O2 levels in which to culture cells, coupled with a lack of the technology to replicate and maintain a physiological O2 environment in vitro, has hindered addressing this issue thus far. In this review, we aim to address the current understanding of tissue Po2 distribution in vivo and summarize the attempts made to replicate these conditions in vitro. The state-of-the-art techniques employed to accurately determine O2 levels, as well as the issues associated with reproducing physiological O2 levels in vitro, are also critically reviewed. We aim to provide the framework for researchers to undertake cell culture under O2 levels relevant to specific tissues and organs. We envisage that this review will facilitate a paradigm shift, enabling translation of findings under physiological conditions in vitro to disease pathology and the design of novel therapeutics.
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Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
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7
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Zhang B, Li Y, Wang G, Jia Z, Li H, Peng Q, Gao Y. Fabrication of agarose concave petridish for 3D-culture microarray method for spheroids formation of hepatic cells. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:49. [PMID: 29675647 DOI: 10.1007/s10856-018-6058-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 04/10/2018] [Indexed: 02/05/2023]
Abstract
Liver is one of the most important organ in the body. But there are many limitations about liver transplantation for liver failure. It is quite important to develop the xenogeneic biological liver for providing an alternation to transplantation or liver regeneration. In this paper, we proposed a method to construct a novel kind of agarose 3D-culture concave microwell array for spheroids formation of hepatic cells. Using the 3D printing method, the microwell array was fabricated with an overall size of 6.4 mm × 6.4 mm, containing 121 microwells with 400 μm width/400 μm thickness. By exploiting the Polydimethylsiloxane (PDMS) membranes as a bridge, we finally fabricated the agarose one. We co-cultured three types of liver cells with bionics design in the microwell arrays. Using the methods described above, the resulting co-formed hepatocyte spheroids maintained the high viability and stable liver-specific functions. This engineered agarose concave microwell array could be a potentially useful tool for forming the elements for biological liver support. After developing the complete system, we also would consider to scale up the application of this system. It will be not only applied to the therapy of human organ damage, but also to the development of disease models and drug screening models.
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Affiliation(s)
- Binbin Zhang
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China
| | - Yang Li
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China
| | - Gaoshang Wang
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China
| | - Zhidong Jia
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China
| | - Haiyan Li
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China
- Department of Pharmacology, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Qing Peng
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China.
| | - Yi Gao
- Department of Hepatobiliary Surgery II,Guangdong Provincial Research Center for Artificial Organ and Tissue Engineering, Guangzhou Clinical Research and Transformation Center for Artificial Liver, Institute of Regenerative Medicine, Zhujiang Hospital of Southern Medical University, Guangzhou, 510000, Guangdong Province, China.
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8
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Gheibi P, Son KJ, Stybayeva G, Revzin A. Harnessing endogenous signals from hepatocytes using a low volume multi-well plate. Integr Biol (Camb) 2018; 9:427-435. [PMID: 28353687 DOI: 10.1039/c7ib00010c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hepatocytes are highly differentiated epithelial cells that lose their phenotype and function when removed from the in vivo environment. Given the importance of hepatic cultures for drug toxicity, bioartificial liver assist devices and basic biology studies, considerable efforts have been focused on the maintenance of hepatic function in vitro. The methods used to date include co-cultivation of hepatocytes with stromal cells, organizing these cells into spheroids and imbedding them into bioactive gels. Our team has recently demonstrated that primary rat hepatocytes confined to microfluidic channels in the absence of convection maintained the epithelial phenotype through upregulation of endogenous signals including hepatocyte growth factor (HGF). The objective of the present study was to transition from microfluidic devices, which are somewhat specialized and challenging to use, towards low volume multiwell plates ubiquitous in biology laboratories. Using a combination of 3D printing and micromolding we have constructed inserts that can be placed into standard 12-well plates and can be used to create low volume culture conditions under which primary hepatocytes maintained a differentiated phenotype. This phenotype enhancement was confirmed by hepatic function assays including albumin synthesis and expression. Importantly we confirmed upregulation of HGF inside the low volume culture plates and demonstrated that inhibition of HGF signaling degraded the hepatic phenotype in our cell culture platform. Overall, this study outlines a new cell culture system that leverages the low volume effects of microfluidic channels in a multiwell plate format. Beyond hepatocytes, such a system may be of use in the maintenance of other difficult-to-culture cells including stem cells and primary cancer cells.
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Affiliation(s)
- Pantea Gheibi
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
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9
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Chan JY, Ooi EH. Sensitivity of thermophysiological models of cryoablation to the thermal and biophysical properties of tissues. Cryobiology 2016; 73:304-315. [DOI: 10.1016/j.cryobiol.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
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10
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Fong CY, Subramanian A, Biswas A, Bongso A. Freezing of Fresh Wharton's Jelly From Human Umbilical Cords Yields High Post-Thaw Mesenchymal Stem Cell Numbers for Cell-Based Therapies. J Cell Biochem 2015; 117:815-27. [PMID: 26365815 DOI: 10.1002/jcb.25375] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 01/02/2023]
Abstract
Some cord blood banks freeze entire pieces of UC (mixed cord, MC) which after post-thaw yields mixed heterogeneous populations of mesenchymal stem cells (MSCs) from all its microanatomical compartments. Freezing of such entire tissues results in sub-optimal post-thaw cell recovery because of poor cryoprotectant diffusion and intracellular ice-formation, heat and water transport issues, and damage to intercellular junctions. To develop a simple method of harvesting pure homogeneous MSCs for cord blood banks, we compared the post-thaw behavior of three groups of frozen UC tissues: (i) freshly harvested WJ without cell separation; (ii) MSCs isolated from WJ (WJSC); and (iii) MC, WJ, and WJSC produced high post-thaw cell survival rates (93.52 ± 6.12% to 90.83 ± 4.51%) and epithelioid monolayers within 24 h in primary culture whereas post-thaw MC explants showed slow growth with mixed epithelioid and fibroblastic cell outgrowths after several days. Viability and proliferation rates of post-thawed WJ and hWJSC were significantly greater than MC. Post-thaw WJ and WJSC produced significantly greater CD24(+) and CD108(+) fluorescence intensities and significantly lower CD40(+) contaminants. Post-thaw WJ and WJSC produced significantly lesser annexin-V-positive and sub-G1 cells and greater degrees of osteogenic and chondrogenic differentiation compared to MC. qRT-PCR analysis of post-thaw MC showed significant decreases in anti-apoptotic gene expression (SURVIVIN, BCL2) and increases in pro-apoptotic (BAX) and cell cycle regulator genes (P53, P21, ROCK 1) compared to WJ and WJSC. We conclude that freezing of fresh WJ is a simple and reliable method of generating large numbers of clinically utilizable MSCs for cell-based therapies.
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Affiliation(s)
- Chui-Yee Fong
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, 119228, Singapore
| | - Arjunan Subramanian
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, 119228, Singapore
| | - Arijit Biswas
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, 119228, Singapore
| | - Ariff Bongso
- Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge, 119228, Singapore
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11
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A microfluidically perfused three dimensional human liver model. Biomaterials 2015; 71:119-131. [PMID: 26322723 DOI: 10.1016/j.biomaterials.2015.08.043] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 01/21/2023]
Abstract
Within the liver, non-parenchymal cells (NPCs) are critically involved in the regulation of hepatocyte polarization and maintenance of metabolic function. We here report the establishment of a liver organoid that integrates NPCs in a vascular layer composed of endothelial cells and tissue macrophages and a hepatic layer comprising stellate cells co-cultured with hepatocytes. The three-dimensional liver organoid is embedded in a microfluidically perfused biochip that enables sufficient nutrition supply and resembles morphological aspects of the human liver sinusoid. It utilizes a suspended membrane as a cell substrate mimicking the space of Disse. Luminescence-based sensor spots were integrated into the chip to allow online measurement of cellular oxygen consumption. Application of microfluidic flow induces defined expression of ZO-1, transferrin, ASGPR-1 along with an increased expression of MRP-2 transporter protein within the liver organoids. Moreover, perfusion was accompanied by an increased hepatobiliary secretion of 5(6)-carboxy-2',7'-dichlorofluorescein and an enhanced formation of hepatocyte microvilli. From this we conclude that the perfused liver organoid shares relevant morphological and functional characteristics with the human liver and represents a new in vitro research tool to study human hepatocellular physiology at the cellular level under conditions close to the physiological situation.
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12
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Usta OB, McCarty WJ, Bale S, Hegde M, Jindal R, Bhushan A, Golberg I, Yarmush ML. Microengineered cell and tissue systems for drug screening and toxicology applications: Evolution of in-vitro liver technologies. TECHNOLOGY 2015; 3:1-26. [PMID: 26167518 PMCID: PMC4494128 DOI: 10.1142/s2339547815300012] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The liver performs many key functions, the most prominent of which is serving as the metabolic hub of the body. For this reason, the liver is the focal point of many investigations aimed at understanding an organism's toxicological response to endogenous and exogenous challenges. Because so many drug failures have involved direct liver toxicity or other organ toxicity from liver generated metabolites, the pharmaceutical industry has constantly sought superior, predictive in-vitro models that can more quickly and efficiently identify problematic drug candidates before they incur major development costs, and certainly before they are released to the public. In this broad review, we present a survey and critical comparison of in-vitro liver technologies along a broad spectrum, but focus on the current renewed push to develop "organs-on-a-chip". One prominent set of conclusions from this review is that while a large body of recent work has steered the field towards an ever more comprehensive understanding of what is needed, the field remains in great need of several key advances, including establishment of standard characterization methods, enhanced technologies that mimic the in-vivo cellular environment, and better computational approaches to bridge the gap between the in-vitro and in-vivo results.
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Affiliation(s)
- O B Usta
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - W J McCarty
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - S Bale
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - M Hegde
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - R Jindal
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - A Bhushan
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - I Golberg
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA
| | - M L Yarmush
- Center for Engineering in Medicine at Massachusetts General Hospital, Harvard Medical School and Shriners Hospital for Children, 51 Blossom St., Boston, MA 02114, USA ; Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ 08854, USA
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13
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Abstract
The liver is the largest internal organ in mammals, serving a wide spectrum of vital functions. Loss of liver function due to drug toxicity, progressive fatty liver disease, or viral infection is a major cause of death in the United States of America. Pharmaceutical and cosmetic toxicity screening, basic research and the development of bioartificial liver devices require long-term hepatocyte culture techniques that sustain hepatocyte morphology and function. In recent years, several techniques have been developed that can support high levels of liver-specific gene expression, metabolic function, and synthetic activity for several weeks in culture. These include the collagen double gel configuration, hepatocyte spheroids, coculture with nonparenchymal cells, and micropatterned cocultures. This chapter will cover the current status of hepatocyte culture techniques, including media formulation, oxygen supply, and heterotypic cell-cell interactions.
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Affiliation(s)
- Merav Cohen
- Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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14
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Ng S, March S, Galstian A, Hanson K, Carvalho T, Mota MM, Bhatia SN. Hypoxia promotes liver-stage malaria infection in primary human hepatocytes in vitro. Dis Model Mech 2013; 7:215-24. [PMID: 24291761 PMCID: PMC3917242 DOI: 10.1242/dmm.013490] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Homeostasis of mammalian cell function strictly depends on balancing oxygen exposure to maintain energy metabolism without producing excessive reactive oxygen species. In vivo, cells in different tissues are exposed to a wide range of oxygen concentrations, and yet in vitro models almost exclusively expose cultured cells to higher, atmospheric oxygen levels. Existing models of liver-stage malaria that utilize primary human hepatocytes typically exhibit low in vitro infection efficiencies, possibly due to missing microenvironmental support signals. One cue that could influence the infection capacity of cultured human hepatocytes is the dissolved oxygen concentration. We developed a microscale human liver platform comprised of precisely patterned primary human hepatocytes and nonparenchymal cells to model liver-stage malaria, but the oxygen concentrations are typically higher in the in vitro liver platform than anywhere along the hepatic sinusoid. Indeed, we observed that liver-stage Plasmodium parasite development in vivo correlates with hepatic sinusoidal oxygen gradients. Therefore, we hypothesized that in vitro liver-stage malaria infection efficiencies might improve under hypoxia. Using the infection of micropatterned co-cultures with Plasmodium berghei, Plasmodium yoelii or Plasmodium falciparum as a model, we observed that ambient hypoxia resulted in increased survival of exo-erythrocytic forms (EEFs) in hepatocytes and improved parasite development in a subset of surviving EEFs, based on EEF size. Further, the effective cell surface oxygen tensions (pO2) experienced by the hepatocytes, as predicted by a mathematical model, were systematically perturbed by varying culture parameters such as hepatocyte density and height of the medium, uncovering an optimal cell surface pO2 to maximize the number of mature EEFs. Initial mechanistic experiments revealed that treatment of primary human hepatocytes with the hypoxia mimetic, cobalt(II) chloride, as well as a HIF-1α activator, dimethyloxalylglycine, also enhance P. berghei infection, suggesting that the effect of hypoxia on infection is mediated in part by host-dependent HIF-1α mechanisms.
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Affiliation(s)
- Shengyong Ng
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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15
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Materne EM, Tonevitsky AG, Marx U. Chip-based liver equivalents for toxicity testing--organotypicalness versus cost-efficient high throughput. LAB ON A CHIP 2013; 13:3481-95. [PMID: 23722971 DOI: 10.1039/c3lc50240f] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Drug-induced liver toxicity dominates the reasons for pharmaceutical product ban, withdrawal or non-approval since the thalidomide disaster in the late-1950s. Hopes to finally solve the liver toxicity test dilemma have recently risen to a historic level based on the latest progress in human microfluidic tissue culture devices. Chip-based human liver equivalents are envisaged to identify liver toxic agents regularly undiscovered by current test procedures at industrial throughput. In this review, we focus on advanced microfluidic microscale liver equivalents, appraising them against the level of architectural and, consequently, functional identity with their human counterpart in vivo. We emphasise the inherent relationship between human liver architecture and its drug-induced injury. Furthermore, we plot the current socio-economic drug development environment against the possible value such systems may add. Finally, we try to sketch a forecast for translational innovations in the field.
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Affiliation(s)
- Eva-Maria Materne
- Technische Universität Berlin, Institute of Biotechnology, Department Medical Biotechnology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
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16
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Tan GDS, Toh GW, Birgersson E, Robens J, van Noort D, Leo HL. A thin-walled polydimethylsiloxane bioreactor for high-density hepatocyte sandwich culture. Biotechnol Bioeng 2013; 110:1663-73. [PMID: 23280535 DOI: 10.1002/bit.24822] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/12/2012] [Accepted: 12/13/2012] [Indexed: 11/10/2022]
Abstract
In vitro drug testing requires long-term maintenance of hepatocyte liver specific functions. Hepatocytes cultured at a higher seeding density in a sandwich configuration exhibit an increased level of liver specific functions when compared to low density cultures due to the better cell to cell contacts that promote long term maintenance of polarity and liver specific functions. However, culturing hepatocytes at high seeding densities in a standard 24-well plate poses problems in terms of the mass transport of nutrients and oxygen to the cells. In view of this drawback, we have developed a polydimethylsiloxane (PDMS) bioreactor that was able to maintain the long-term liver specific functions of a hepatocyte sandwich culture at a high seeding density. The bioreactor was fabricated with PDMS, an oxygen permeable material, which allowed direct oxygenation and perfusion to take place simultaneously. The mass transport of oxygen and the level of shear stress acting on the cells were analyzed by computational fluid dynamics (CFD). The combination of both direct oxygenation and perfusion has a synergistic effect on the liver specific function of a high density hepatocyte sandwich culture over a period of 9 days.
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Affiliation(s)
- Guo-Dong Sean Tan
- Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore.
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17
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Meyer C, Dzieran J, Liu Y, Schindler F, Munker S, Müller A, Coulouarn C, Dooley S. Distinct dedifferentiation processes affect caveolin-1 expression in hepatocytes. Cell Commun Signal 2013; 11:6. [PMID: 23339737 PMCID: PMC3598962 DOI: 10.1186/1478-811x-11-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/21/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Dedifferentiation and loss of hepatocyte polarity during primary culture of hepatocytes are major drawbacks for metabolic analyses. As a prominent profibrotic cytokine and potent inducer of epithelial mesenchymal transition (EMT), TGF-β contributes to these processes in liver epithelial cells. Yet, a distinction between culture dependent and TGF-β driven hepatocyte dedifferentiation has not been shown to date. RESULTS Here, we show that in both settings, mesenchymal markers are induced. However, upregulation of Snai1 and downregulation of E-Cadherin are restricted to TGF-β effects, neglecting a full EMT of culture dependent hepatocyte dedifferentiation. Mechanistically, the latter is mediated via FAK/Src/ERK/AKT pathways leading to the induction of the oncogene caveolin-1 (Cav1). Cav1 was recently proposed as a new EMT marker, but our results demonstrate Cav1 is not up-regulated in TGF-β mediated hepatocyte EMT, thus limiting validity of its use for this purpose. Importantly, marking differences on Cav1 expression exist in HCC cell lines. Whereas well differentiated HCC cell lines exhibit low and inducible Cav1 protein levels - by TGF-β in a FAK/Src dependent manner, poorly differentiated cell lines display high Cav1 expression levels which are not further modulated by TGF-β. CONCLUSIONS This study draws a detailed distinction between intrinsic and TGF-β mediated hepatocyte dedifferentiation and elucidates cellular pathways involved. Additionally, by evaluating the regulation of the oncogene Cav1, we provide evidence to argue against Cav1 as a reliable EMT marker.
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Affiliation(s)
- Christoph Meyer
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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18
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Abstract
The liver is the largest internal organ in mammals, serving a wide spectrum of vital functions. Loss of liver function due to drug toxicity or viral infection is a major cause of death in the United States. The development of Bioartificial Liver (BAL) devices and the demand for pharmaceutical and cosmetic toxicity screening require the development of long-term hepatocyte culture techniques. However, primary hepatocytes rapidly lose their cuboidal morphology and liver-specific functions over a few days in culture. Accumulation of stress fibers, loss of metabolic function, and cell death are known phenomena. In recent years, several techniques were developed that can support high levels of liver-specific gene expression, metabolic and synthetic function for several weeks in culture. These include the collagen double-gel configuration, hepatocyte spheroids, coculture with endothelial cells, and micropatterned cocultures with 3T3-J2 fibroblasts. This chapter covers the current status of hepatocyte culture techniques, including: hepatocyte isolation, media formulation, oxygen supply, heterotypic cell-cell interactions, and basic functional assays.
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Affiliation(s)
- Maria Shulman
- The Selim and Rachel Benin School of Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
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19
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Rotem A, Toner M, Bhatia S, Foy BD, Tompkins RG, Yarmush ML. Oxygen is a factor determining in vitro tissue assembly: Effects on attachment and spreading of hepatocytes. Biotechnol Bioeng 2012; 43:654-60. [PMID: 18615765 DOI: 10.1002/bit.260430715] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Many recent studies related to the development of bioartificial liver devices have utilized hepatocytes cultured within devices of various geometries. Because hepatocytes are anchorage-dependent cells, they need to attach and spread onto the extracellular matrix to be able to function, a process that requires energy. Thus, it is important to deliver enough oxygen to hepatocytes contained within bioartificial liver devices during the early phase of cellular organization while the cells interact with the extracellular matrix. In this study, we investigated the effect of oxygen on the attachment and spreading of hepatocytes. Increasing the gas phase oxygen from 0 to 160 mmHg resulted in an increase in the percentage of cells attaching from 43.0 +/- 5.8% to 103.6 +/- 29%, 1 h after seeding. In a similar manner, increasing the gas phase oxygen from 0 to 160 mmHg resulted in an increase of the projected surface area from 310 +/- 35 to 827 +/- 127 mum(2), 24 h after seeding. Furthermore, the partial pressure of oxygen at the cell level was estimated using a diffusion-reaction model. The model indicated that a cell surface oxygen partial pressure of 0.064 mmHg was required for the half-maximal (K(m) (a)) attachment of hepatocytes to collagen-based substrate. On the other hand, the K(m) (s) value of the spreading process was predicted to be 0.13 mmHg. The results of this study demonstrate the importance of oxygen during the initial stages of attachment and spreading of hepatocytes, and it has important implications in the design of hepatocyte-based bioartificial liver devices. (c) 1994 John Wiley & Sons, Inc.
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Affiliation(s)
- A Rotem
- Surgical Services, Massachusetts General Hospital, and the Shriners Burns Institute, Department of Surgery, Harvard Medical School, Boston, Massachusetts 02114
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20
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LeCluyse EL, Witek RP, Andersen ME, Powers MJ. Organotypic liver culture models: meeting current challenges in toxicity testing. Crit Rev Toxicol 2012; 42:501-48. [PMID: 22582993 PMCID: PMC3423873 DOI: 10.3109/10408444.2012.682115] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 03/26/2012] [Accepted: 03/30/2012] [Indexed: 02/07/2023]
Abstract
Prediction of chemical-induced hepatotoxicity in humans from in vitro data continues to be a significant challenge for the pharmaceutical and chemical industries. Generally, conventional in vitro hepatic model systems (i.e. 2-D static monocultures of primary or immortalized hepatocytes) are limited by their inability to maintain histotypic and phenotypic characteristics over time in culture, including stable expression of clearance and bioactivation pathways, as well as complex adaptive responses to chemical exposure. These systems are less than ideal for longer-term toxicity evaluations and elucidation of key cellular and molecular events involved in primary and secondary adaptation to chemical exposure, or for identification of important mediators of inflammation, proliferation and apoptosis. Progress in implementing a more effective strategy for in vitro-in vivo extrapolation and human risk assessment depends on significant advances in tissue culture technology and increasing their level of biological complexity. This article describes the current and ongoing need for more relevant, organotypic in vitro surrogate systems of human liver and recent efforts to recreate the multicellular architecture and hemodynamic properties of the liver using novel culture platforms. As these systems become more widely used for chemical and drug toxicity testing, there will be a corresponding need to establish standardized testing conditions, endpoint analyses and acceptance criteria. In the future, a balanced approach between sample throughput and biological relevance should provide better in vitro tools that are complementary with animal testing and assist in conducting more predictive human risk assessment.
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Affiliation(s)
- Edward L LeCluyse
- The Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
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21
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Measurement of Cryoprotectant Permeability in Adherent Endothelial Cells and Applications to Cryopreservation. Cell Mol Bioeng 2012. [DOI: 10.1007/s12195-012-0235-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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22
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Sambu S, Xu X, Ye H, Cui ZF. Predicting the survival rate of mouse embryonic stem cells cryopreserved in alginate beads. Proc Inst Mech Eng H 2012; 225:1092-107. [PMID: 22292208 DOI: 10.1177/0954411911418568] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Stem cell cryopreservation in three-dimensional (3D) scaffolds may offer better protection to cells leading to higher survival rates. However, it introduces heterogeneity in cryoprotective agent (CPA) concentrations, durations of exposure to CPA, and freezing and thawing rate within constructs. This paper applies a mathematical model which couples the mass transport of dimethyl sulphoxide (DMSO) in a cell-seeded spherical construct and cell membrane transport into mouse embryonic stem cells (mESCs) to predict overall cell survival rate (CSR) based on CPA equilibrium exposure times (t(E)) and concentrations. The effect of freeze-concentration is also considered. To enable such a prediction, a contour plot was constructed using experimental data obtained in cryopreservation of cell suspensions with DMSO at a cooling rate of 1 degrees C/min. Thereafter, the diffusion in the alginate bead and the membrane transport of CPA was numerically simulated. Results were mapped onto the survival rate contours yielding 'predicted' CSR. The effects of loading time, hindrance, construct radius, and CPA concentration on predicted CSR were examined. From these results, an operation window with upper and lower t(E) of 12-19 min (for 0.6 mm radius beads and 1.4 M DMSO) yielded an overall viability of 60 per cent. The model predictions and the best experimental cryopreservation results with encapsulated mESCs were in agreement. Hence, optimization based on post-thaw CSR can accelerate the identification of cryopreservation protocols and parameters for maximizing cell survival.
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Affiliation(s)
- S Sambu
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK
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23
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Choi J, Bischof JC. Cooling rate dependent biophysical and viability response shift with attachment state in human dermal fibroblast cells. Cryobiology 2011; 63:285-91. [PMID: 22020295 DOI: 10.1016/j.cryobiol.2011.09.142] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 09/19/2011] [Accepted: 09/30/2011] [Indexed: 10/16/2022]
Abstract
While studies on the freezing of cells in suspension have been carried out extensively, corresponding studies with cells in the attached state and in tissue or tissue-equivalents are less developed. As attachment is a hallmark of the tissue state it is important to understand its impact on biophysics and viability to better apply freezing towards tissue preservation. The current study reports on observed biophysical response changes observed during freezing human dermal fibroblasts in suspension, attached cell, and fibrin tissue-equivalent models. Specifically, intracellular ice formation is shown to increase and dehydration is inferred to increase from suspension to attached systems. Biophysical model parameters fit to these experimental observations reflect the higher kinetics in the attached state. Post-thaw viability values from fast cooling rates were higher for suspension systems, and correlated well with the amount of IIF observed. On the other hand, viability values from slow cooling rates were higher for attached systems, although the degree of dehydration was predicted to be comparable to suspension cells. This disconnect between biophysics and viability predictions at slow rates clearly requires further investigation as it runs counter to our current understanding of dehydration injury in cells. This may suggest a possible protective effect of the attachment state on cell systems.
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Affiliation(s)
- Jeunghwan Choi
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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24
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He X. Thermostability of biological systems: fundamentals, challenges, and quantification. Open Biomed Eng J 2011; 5:47-73. [PMID: 21769301 PMCID: PMC3137158 DOI: 10.2174/1874120701105010047] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 12/25/2022] Open
Abstract
This review examines the fundamentals and challenges in engineering/understanding the thermostability of biological systems over a wide temperature range (from the cryogenic to hyperthermic regimen). Applications of the bio-thermostability engineering to either destroy unwanted or stabilize useful biologicals for the treatment of diseases in modern medicine are first introduced. Studies on the biological responses to cryogenic and hyperthermic temperatures for the various applications are reviewed to understand the mechanism of thermal (both cryo and hyperthermic) injury and its quantification at the molecular, cellular and tissue/organ levels. Methods for quantifying the thermophysical processes of the various applications are then summarized accounting for the effect of blood perfusion, metabolism, water transport across cell plasma membrane, and phase transition (both equilibrium and non-equilibrium such as ice formation and glass transition) of water. The review concludes with a summary of the status quo and future perspectives in engineering the thermostability of biological systems.
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Affiliation(s)
- Xiaoming He
- Multiscale Biothermostability Engineering Laboratory, Department of Mechanical Engineering and Biomedical Engineering Program, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA
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25
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Yang G, Veres M, Szalai G, Zhang A, Xu LX, He X. Biotransport phenomena in freezing mammalian oocytes. Ann Biomed Eng 2010; 39:580-91. [PMID: 20848315 DOI: 10.1007/s10439-010-0158-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 08/31/2010] [Indexed: 11/30/2022]
Abstract
Water transport across the cell plasma membrane and intracellular ice formation (IIF)-the two biophysical events that may cause cell injury during cryopreservation-were studied by cryomicroscopy and modeling using mammalian (Peromyscus) oocytes. Unusually high activation energy for water transport across the cell plasma membrane was identified indicating that the water transport process is unusually sensitive to temperature (and cooling rate). Although literally all studies on IIF were conducted using protocols with ice-seeding (seeding extracellular ice usually at ≥-7 °C), it is not used for cell cryopreservation by vitrification that is becoming increasingly popular today. In this article, we show that ice-seeding has a significant impact on IIF. With ice-seeding and cooling at 60 °C/min, IIF was observed to occur over a wide range from approximately -8 to -48 °C with a clear change of the ice nucleation mechanism (from surface- to volume-catalyzed nucleation) at approximately -43 °C. On the contrary, without ice-seeding, IIF occurred over a much narrower range from approximately -19 to -27 °C without a noticeable change of the nucleation mechanism. Moreover, the kinetics of IIF without ice-seeding was found to be strongly temperature (and cooling rate) dependent. These findings indicate the importance of quantifying the IIF kinetics in the absence of ice-seeding during cooling for development of optimal vitrification protocols of cell cryopreservation.
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Affiliation(s)
- Geer Yang
- Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA
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26
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Rössner E, Smith MD, Petschke B, Schmidt K, Vitacolonna M, Syring C, von Versen R, Hohenberger P. Epiflex(®) a new decellularised human skin tissue transplant: manufacture and properties. Cell Tissue Bank 2010; 12:209-17. [PMID: 20574693 DOI: 10.1007/s10561-010-9187-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 06/11/2010] [Indexed: 11/30/2022]
Abstract
The manufacture and initial testing of a new human tissue transplant is described. Epiflex(®) is a human acellular dermis transplant that is manufactured from skin recovered from screened consenting donors according to validated and approved methods. The transplant is approved as a drug in Germany. The safety, stability and usability of the transplant are discussed with respect to the results of sterility, residual moisture content and rehydration tests. Histological and confocal laser scanning microscopy experiments and analysis of oxygen and water vapour permeability demonstrate that the native extracellular matrix structure and transport properties of human connective tissue are retained in the transplant. Results from initial clinical investigations suggest that Epiflex(®) can be used successfully in the treatment of burns, hypertrophic scars and as a transplant seeded with autologous dermal fibroblasts for soft-tissue regeneration in settings with wound healing problems following multi-modal treatments for sarcomas of the extremities.
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Affiliation(s)
- E Rössner
- Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Centre Mannheim, Theodor- Kutzer- Ufer 1-3, 68167, Mannheim, Germany.
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27
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Xu F, Moon S, Zhang X, Shao L, Song YS, Demirci U. Multi-scale heat and mass transfer modelling of cell and tissue cryopreservation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2010; 368:561-83. [PMID: 20047939 PMCID: PMC3263795 DOI: 10.1098/rsta.2009.0248] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cells and tissues undergo complex physical processes during cryopreservation. Understanding the underlying physical phenomena is critical to improve current cryopreservation methods and to develop new techniques. Here, we describe multi-scale approaches for modelling cell and tissue cryopreservation including heat transfer at macroscale level, crystallization, cell volume change and mass transport across cell membranes at microscale level. These multi-scale approaches allow us to study cell and tissue cryopreservation.
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Affiliation(s)
- Feng Xu
- Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Sangjun Moon
- Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Xiaohui Zhang
- Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Lei Shao
- Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Young Seok Song
- Polymer System Division, Fiber System Engineering, Dankook University, Yongin-si, Gyeonggi-do, Korea
- Author for correspondence (; )
| | - Utkan Demirci
- Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Harvard-Massachusetts Institute of Technology Health Sciences and Technology, Cambridge, MA, USA
- Author for correspondence (; )
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28
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Powers DE, Millman JR, Bonner-Weir S, Rappel MJ, Colton CK. Accurate control of oxygen level in cells during culture on silicone rubber membranes with application to stem cell differentiation. Biotechnol Prog 2009; 26:805-18. [DOI: 10.1002/btpr.359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Sharma NS, Wallenstein EJ, Novik E, Maguire T, Schloss R, Yarmush ML. Enrichment of hepatocyte-like cells with upregulated metabolic and differentiated function derived from embryonic stem cells using S-NitrosoAcetylPenicillamine. Tissue Eng Part C Methods 2009; 15:297-306. [PMID: 19196121 DOI: 10.1089/ten.tec.2008.0303] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The generation of a large number of fully functional hepatocytes from a renewable cell source can provide an unlimited resource for bioartificial liver devices and cell replacement therapies. We have established a directed differentiation system using sodium butyrate treatment to generate an enriched population of hepatocyte-like cells from embryonic stem cells. A metabolic analysis of the hepatocyte populations revealed glycolytic and mitochondrial phenotypes similar to mouse hepatoma cells, implying that these cells represent an immature hepatocyte phenotype. To mediate further differentiation, S-NitrosoAcetylPenicillamine (SNAP), a nitric oxide donor, was utilized to induce mitochondrial development in the precursor populations. A comparative analysis of the different treated populations showed that 500microM SNAP treatment resulted in the generation of an enriched population of metabolically mature hepatocyte-like cells with increased differentiated function. Specifically, 500microM SNAP treatment increased glucose consumption, lactate production rates, mitochondrial mass, and potential as compared to untreated populations. In addition, functional analysis revealed that intracellular albumin content, urea secretion rates, and cytochrome P450 7a1 promoter activity were increased in the treated population. The methodology described here to generate an enriched population of metabolically and functionally mature hepatocyte-like cells may have potential implications in drug discovery and regenerative medicine.
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Affiliation(s)
- Nripen S Sharma
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey, USA
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30
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Oxygen-mediated enhancement of primary hepatocyte metabolism, functional polarization, gene expression, and drug clearance. Proc Natl Acad Sci U S A 2009; 106:15714-9. [PMID: 19720996 DOI: 10.1073/pnas.0906820106] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The liver is a major site for the metabolism of xenobiotic compounds due to its abundant level of phase I/II metabolic enzymes. With the cost of drug development escalating to over $400 million/drug there is an urgent need for the development of rigorous models of hepatic metabolism for preclinical screening of drug clearance and hepatotoxicity. Here, we present a microenvironment in which primary human and rat hepatocytes maintain a high level of metabolic competence without a long adaptation period. We demonstrate that co-cultures of hepatocytes and endothelial cells in serum-free media seeded under 95% oxygen maintain functional apical and basal polarity, high levels of cytochrome P450 activity, and gene expression profiles on par with freshly isolated hepatocytes. These oxygenated co-cultures demonstrate a remarkable ability to predict in vivo drug clearance rates of both rapid and slow clearing drugs with an R(2) of 0.92. Moreover, as the metabolic function of oxygenated co-cultures stabilizes overnight, preclinical testing can be carried out days or even weeks before other culture methods, significantly reducing associated labor and cost. These results are readily extendable to other culture configurations including three-dimensional culture, bioreactor studies, as well as microfabricated co-cultures.
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31
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Nagrath D, Xu H, Tanimura Y, Zuo R, Berthiaume F, Avila M, Yarmush R, Yarmush ML. Metabolic preconditioning of donor organs: defatting fatty livers by normothermic perfusion ex vivo. Metab Eng 2009; 11:274-83. [PMID: 19508897 DOI: 10.1016/j.ymben.2009.05.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 04/26/2009] [Accepted: 05/22/2009] [Indexed: 12/12/2022]
Abstract
Fatty liver is a significant risk factor for liver transplantation, and accounts for nearly half of the livers rejected from the donor pool. We hypothesized that metabolic preconditioning via ex vivo perfusion of the liver graft can reduce fat content and increase post-transplant survival to an acceptable range. We describe a perfusate medium containing agents that promote the defatting of hepatocytes and explanted livers. Defatting agents were screened on cultured hepatocytes made fatty by pre-incubation with fatty acids. The most effective agents were then used on fatty livers. Fatty livers were isolated from obese Zucker rats and normothermically perfused with medium containing a combination of defatting agents. This combination decreased the intracellular lipid content of cultured hepatocytes by 35% over 24h, and of perfused livers by 50% over 3h. Metabolite analysis suggests that the defatting cocktail upregulated both lipid oxidation and export. Furthermore, gene expression analysis for several enzymes and transcription factors involved in fatty acid oxidation and triglyceride clearance were elevated. We conclude that a cocktail of defatting agents can be used to rapidly clear excess lipid storage in fatty livers, thus providing a new means to recondition donor livers deemed unacceptable or marginally acceptable for transplantation.
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Affiliation(s)
- Deepak Nagrath
- Center for Engineering in Medicine/Surgical Services, Massachusetts General Hospital, Harvard Medical School, and the Shriners Hospitals for Children, Boston, MA 02114, USA
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32
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Han B, Miller JD, Jung JK. Freezing-induced fluid-matrix interaction in poroelastic material. J Biomech Eng 2009; 131:021002. [PMID: 19102561 DOI: 10.1115/1.3005170] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Freezing of biological tissue is emerging in various biomedical applications. The success of these applications requires precise control of the tissue functionality, which is closely associated with the microstructure of the extracellular matrix (ECM). In the present study, the spatiotemporal effects of freezing on the ECM were experimentally and theoretically investigated by approximating biological tissue as a poroelastic material saturated with interstitial fluid. The experiments with type I collagen gel showed that its matrix underwent two distinct levels of structural changes due to freezing: enlarged pore structure of the matrix and increased collagen fibril diameters. The extent of these changes was augmented as the freezing temperature was lowered. The theoretical model suggested that the interstitial fluid might be transported toward the unfrozen region from the phase change interface due to the volumetric expansion associated with the water-ice phase change, and the transported fluid could interact with the matrix and enlarge its pore structure. The model also illustrated the effects of matrix structural properties on this interaction including initial porosity, hydraulic conductivity, and elastic modulus. These results imply that an identical macroscopic freezing protocol may result in different microstructural alterations of poroelastic materials depending on the structural properties of the matrix. This may be relevant to understanding the tissue-type dependent outcomes of cryomedicine applications and be useful in designing cryomedicine applications for a wide variety of tissues.
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Affiliation(s)
- Bumsoo Han
- Department of Mechanical and Aerospace Engineering, University of Texas at Arlington, Arlington, TX 76019, USA.
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33
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Kleinhans FW, Mazur P. Determination of the water permeability (Lp) of mouse oocytes at -25 degrees C and its activation energy at subzero temperatures. Cryobiology 2008; 58:215-24. [PMID: 19161999 DOI: 10.1016/j.cryobiol.2008.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 10/15/2008] [Accepted: 12/18/2008] [Indexed: 10/21/2022]
Abstract
Typically, subzero permeability measurements are experimentally difficult and infrequently reported. Here we report an approach we have applied to mouse oocytes. Interrupted cooling involves rapidly cooling oocytes (50 degrees C/min) to an intermediate temperature above the intracellular nucleation zone, holding them for up to 40 min while they dehydrate, and then rapidly cooling them to -70 degrees C or below. If the intermediate holding temperature and holding time are well chosen, high post thaw survival of the oocytes is possible because the freezable water is removed during the hold. The length of time required for the exit of the freezable water allows the water permeability at that temperature to be determined. These experiments used 1.5M ethylene glycol in PBS and included a transient hold of 2 min for equilibration at -10 degrees C, just below the extracellar ice formation temperature. We obtain an Lp=1.8 x 10(-3)microm min(-1)atm(-1) at -25 degrees C based on a hold time of 30 min yielding 80% survival and the premise that most of the freezable water is removed during the 30 min hold. If we assume that the water permeability is a continuous function of temperature and that its Ea changes at 0 degrees C, we obtain a subzero Ea of 21 kcal/mol; higher than the suprazero value of 14 kcal/mol. A number of assumptions are required for these water loss calculations and the resulting value of Lp can vary by up to a factor of 2, depending on the choices make.
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Affiliation(s)
- F W Kleinhans
- Fundamental and Applied Cryobiology Group, Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37932-2575, USA.
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Powers DE, Millman JR, Huang RB, Colton CK. Effects of oxygen on mouse embryonic stem cell growth, phenotype retention, and cellular energetics. Biotechnol Bioeng 2008; 101:241-54. [PMID: 18727033 DOI: 10.1002/bit.21986] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Most embryonic stem (ES) cell research is performed with a gas phase oxygen partial pressure (pO(2)) of 142 mmHg, whereas embryonic cells in early development are exposed to pO(2) values of 0-30 mmHg. To understand effects of these differences, we studied murine ES (mES) growth, maintenance of stem cell phenotype, and cell energetics over a pO(2) range of 0-285 mmHg, in the presence or absence of differentiation-suppressing leukemia inhibitory factor (LIF). With LIF, growth rate was sensitive to pO(2) but constant with time, and expression of self-renewal transcription factors decreased at extremes of pO(2). Subtle morphological changes suggested some early differentiation, but cells retained the ability to differentiate into derivatives of all three germ layers at low pO(2). Without LIF, growth rate decreased with time, and self-renewal transcription factor mRNA decreased further. Gross morphological changes occurred, and overt differentiation occurred at all pO(2). These findings suggested that hypoxia in the presence of LIF promoted limited early differentiation. ES cells survived oxygen starvation with negligible cell death by increasing anaerobic metabolism within 48 h of anoxic exposure. Decreasing pO(2) to 36 mmHg or lower decreased oxygen consumption rate and increased lactate production rate. The fraction of ATP generated aerobically was 60% at or above 142 mmHg and decreased to 0% under anoxia, but the total ATP production rate remained nearly constant at all pO(2). In conclusion, undifferentiated ES cells adapt their energy metabolism to proliferate at all pO(2) between 0 and 285 mmHg. Oxygen has minimal effects on undifferentiated cell growth and phenotype, but may exert more substantial effects under differentiating conditions.
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Affiliation(s)
- Daryl E Powers
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Room 66-452, Cambridge, Massachusetts 02139, USA
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35
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McGuigan AP, Sefton MV. Modular tissue engineering: fabrication of a gelatin-based construct. J Tissue Eng Regen Med 2008; 1:136-45. [PMID: 18038402 DOI: 10.1002/term.14] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Modular tissue-engineered constructs are assembled from sub-millimetre-sized cylindrical modules which are seeded with a surface layer of endothelial cells. The resulting construct is permeated by a network of interconnected, endothelial cell-lined channels to facilitate blood perfusion and nutrient delivery. To provide adequate stiffness, yet consist of a substrate suitable for endothelial cells, modular constructs were fabricated from gelatin, the denatured form of collagen. Gelatin modules containing HepG2 cells or spheroids were fabricated using a sieving process. A surface layer of bovine aortic endothelial cells completely covering the modules was generated within 1 week of seeding. Modules were assembled into constructs within a flow circuit and flow rate-pressure difference profiles measured. Fluid perfusion resulted in negligible construct compaction, even at high flow rates. It was necessary, however, to crosslink the gelatin modules with glutaraldehyde to prevent dissolution at 37 degrees C. This resulted in a significant loss of cell viability within the modules. A strategy to enable non-toxic crosslinking of the gelatin modules is required to fabricate constructs containing viable cells.
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Affiliation(s)
- Alison P McGuigan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
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36
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Engineering cell de-adhesion dynamics on thermoresponsive poly(N-isopropylacrylamide). Acta Biomater 2008; 4:218-29. [PMID: 17964872 DOI: 10.1016/j.actbio.2007.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 08/31/2007] [Accepted: 09/10/2007] [Indexed: 12/20/2022]
Abstract
Poly(N-isopropylacrylamide) (PIPAAm) has been demonstrated as an effective thermoresponsive polymer for non-invasive cell regeneration/recovery. However, little is known about the intricate relationship between the biophysical response of cells and physiochemical properties of PIPAAm during cell recovery. In this study, the de-adhesion kinetics of smooth muscle cell (SMC) on PIPAAm surfaces is probed with unique biophysical techniques. Water-immersion atomic force microscope (AFM) first showed that the nanotopology of PIPAAm surfaces is dependent on the polymerization time and collagen coating. It is found that the initial rate of cell de-adhesion increases with the increase in polymerization time. Moreover, the degree of cell deformation (a/R) and average adhesion energy are reduced with the increase of grafted PIPAAm density during 40min of cell de-adhesion. It has been shown that collagen coating regulates cell adhesion on biomaterial surface. Interestingly, lower collagen density on PIPAAm leads to higher adhesion energy per cell during the initial 20min compared with as-prepared PIPAAm, while the initial rate of cell de-adhesion remains unchanged. In contrast, higher collagen density leads to 50% reduction in the initial rate of cell de-adhesion and higher adhesion energy per cell during the entire 90min. Furthermore, immunostaining of actin provides supporting evidence that the de-adhesion kinetics is correlated with the cytoskeleton transformation during cell de-adhesion below the lower solution critical temperature (LCST).
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37
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Functional modulation of ES-derived hepatocyte lineage cells via substrate compliance alteration. Ann Biomed Eng 2008; 36:865-76. [PMID: 18266108 DOI: 10.1007/s10439-008-9458-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 01/31/2008] [Indexed: 10/22/2022]
Abstract
Pluripotent embryonic stem cells represent a promising renewable cell source to generate a variety of differentiated cell types including hepatocyte lineage cells, and may ultimately be incorporated into extracorporeal bioartificial liver devices and cell replacement therapies. Recently, we and others have utilized sodium butyrate to directly differentiate hepatocyte-like cells from murine embryonic stem cells cultured in a monolayer configuration. However, to incorporate stem cell technology into clinical and pharmaceutical applications, and hopefully increase the therapeutic potential of these differentiated cells for liver disease treatment, a major challenge remains in sustaining differentiated functions for an extended period of time in their secondary culture environment. In the present work, we have investigated the use of polyacrylamide hydrogels with defined mechanical compliances as a cell culture platform for improving and/or stabilizing functions of these hepatocyte-like cells. Several functional assays, e.g., urea secretion, intracellular albumin content, and albumin secretion, were performed to characterize hepatic functions of cells on polyacrylamide gels with stiffnesses of 5, 46.6, and 230 kPa. In conjunction with the mechanical and cell morphological characterization, we showed that hepatic functions of sodium butyrate differentiated cells were sustained and further enhanced on compliant substrates. This study promises to offer insights into regulating stem cell differentiation via mechanical stimuli, and assist us with designing a variety of dynamic culture systems for applications in tissue and cellular engineering.
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38
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Cho CH, Eliason JF, Matthew HW. Application of porous glycosaminoglycan-based scaffolds for expansion of human cord blood stem cells in perfusion culture. J Biomed Mater Res A 2008; 86:98-107. [DOI: 10.1002/jbm.a.31614] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Nahmias Y, Odde DJ. Micropatterning of living cells by laser-guided direct writing: application to fabrication of hepatic-endothelial sinusoid-like structures. Nat Protoc 2007; 1:2288-96. [PMID: 17406470 DOI: 10.1038/nprot.2006.386] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Here, we describe a simple protocol for the design and construction of a laser-guided direct writing (LGDW) system able to micropattern the self-assembly of liver sinusoid-like structures with micrometer resolution in vitro. To the best of our knowledge, LGDW is the only technique able to pattern cells "on the fly" with micrometer precision on arbitrary matrices, including soft gels such as Matrigel. By micropatterning endothelial cells on Matrigel, one can control the self-assembly of vascular structures and associated liver tissue. LGDW is therefore uniquely suited for studying the role of tissue architecture and mechanical properties at the single-cell resolution, and for studying the effects of heterotypic cell-cell interactions underlying processes such as liver morphogenesis, differentiation and angiogenesis. The total time required to carry out this protocol is typically 7 h.
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Affiliation(s)
- Yaakov Nahmias
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, 51 Blossom Street, Boston, Massachusetts 02114, USA
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40
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Thermal Injury Prediction During Cryoplasty Through In Vitro Characterization of Smooth Muscle Cell Biophysics and Viability. Ann Biomed Eng 2007; 36:86-101. [DOI: 10.1007/s10439-007-9383-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 09/13/2007] [Indexed: 01/11/2023]
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41
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Cho CH, Park J, Nagrath D, Tilles AW, Berthiaume F, Toner M, Yarmush ML. Oxygen uptake rates and liver-specific functions of hepatocyte and 3T3 fibroblast co-cultures. Biotechnol Bioeng 2007; 97:188-99. [PMID: 17054120 DOI: 10.1002/bit.21225] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bioartificial liver (BAL) devices have been developed to treat patients undergoing acute liver failure. One of the most important parameters to consider in designing these devices is the oxygen consumption rate of the seeded hepatocytes which are known to have oxygen consumption rates 10 times higher than most other cell types. Hepatocytes in various culture configurations have been tested in BAL devices including those formats that involve co-culture of hepatocytes with other cell types. In this study, we investigated, for the first time, oxygen uptake rates (OUR)s of hepatocytes co-cultured with 3T3-J2 fibroblasts at various hepatocyte to fibroblast seeding ratios. OURs were determined by measuring the rate of oxygen disappearance using a ruthenium-coated optical probe after closing and sealing the culture dish. Albumin and urea production rates were measured to assess hepatocyte function. Lower hepatocyte density co-cultures demonstrated significantly higher OURs (2 to 3.5-fold) and liver- specific functions (1.6-fold for albumin and 4.5-fold for urea production) on a per cell basis than those seeded at higher densities. Increases in OUR correlated well with increased liver-specific functions. OURs (V(m)) were modeled by fitting Michaelis-Menten kinetics and the model predictions closely correlated with the experimental data. This study provides useful information for predicting BAL design parameters that will avoid oxygen limitations, as well as maximize metabolic functions.
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Affiliation(s)
- Cheul H Cho
- Center for Engineering in Medicine, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Shriners Hospitals for Children, Boston, Massachusetts 02114, USA
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42
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Zhang A, Xu LX, Sandison GA, Cheng S. Morphological study of endothelial cells during freezing. Phys Med Biol 2006; 51:6047-60. [PMID: 17110769 DOI: 10.1088/0031-9155/51/23/007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Microvascular injury is recognized as a major tissue damage mechanism of ablative cryosurgery. Endothelial cells lining the vessel wall are thought to be the initial target of freezing. However, details of this injury mechanism are not yet completely understood. In this study, ECMatrix 625 was used to mimic the tumour environment and to allow the endothelial cells cultured in vitro to form the tube-like structure of the vasculature. The influence of water dehydration on the integrity of this structure was investigated. It was found that the initial cell shape change was mainly controlled by water dehydration, dependent on the cooling rate, resulting in the shrinkage of cells in the direction normal to the free surface. As the cooling was prolonged and temperature was lowered, further cell shape change could be induced by the chilling effects on intracellular proteins, and focal adhesions to the basement membrane. Quantitative analysis showed that the freezing induced dehydration greatly enhanced the cell surface stresses, especially in the axial direction. This could be one of the major causes of the final breaking of the cell junction and cell detachment.
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Affiliation(s)
- A Zhang
- School of Life Science and Biotechnology, Shanghai Jiao Tong University, 200240, People's Republic of China
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43
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Nahmias Y, Kramvis Y, Barbe L, Casali M, Berthiaume F, Yarmush ML. A novel formulation of oxygen‐carrying matrix enhances liver‐specific function of cultured hepatocytes. FASEB J 2006; 20:2531-3. [PMID: 17077286 DOI: 10.1096/fj.06-6192fje] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oxygen is an important component of the cellular microenvironment, mediating cell survival, differentiation, and function. Oxygen supply is a limiting factor during culture of highly metabolic cells such as hepatocytes. Here we present a simple formulation of a fluorocarbon-based oxygen carrier embedded in collagen gel that increases oxygen concentration in culture 6-fold. Rat hepatocytes cultured on oxygen carrier-collagen showed a significant increase in viability and function. Cytochrome P450IA1 activity was increased by 140% in serum-free cultures and by 820% in serum-containing cultures. The significantly higher hepatocellular function on oxygen carrier-collagen matrix persisted and increased during long-term culture. Long-term albumin secretion was increased by 350% in serum-free cultures and by 166% in serum-containing culture. Long-term urea secretion was increased by 79% in serum-free cultures and by 76% in serum-containing cultures. We conclude that oxygen supply may limit hepatocyte function in vitro. This limitation can be overcome by addition of an oxygen carrier to the extracellular matrix. Culture of hepatocytes on oxygen-carrying matrix mimics the oxygen-rich environment of the liver and provides a simple method for enhanced long-term function.
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Affiliation(s)
- Yaakov Nahmias
- Center for Engineering in Medicine/Department of Surgery, Massachusetts General Hospital, Shriners Burns Hospital, Harvard Medical School, Boston, MA 02114, USA
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44
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Mareels G, Poyck PPC, Eloot S, Chamuleau RAFM, Verdonck PR. Three-dimensional numerical modeling and computational fluid dynamics simulations to analyze and improve oxygen availability in the AMC bioartificial liver. Ann Biomed Eng 2006; 34:1729-44. [PMID: 17031599 PMCID: PMC1705524 DOI: 10.1007/s10439-006-9169-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Accepted: 07/27/2006] [Indexed: 11/28/2022]
Abstract
A numerical model to investigate fluid flow and oxygen (O(2)) transport and consumption in the AMC-Bioartificial Liver (AMC-BAL) was developed and applied to two representative micro models of the AMC-BAL with two different gas capillary patterns, each combined with two proposed hepatocyte distributions. Parameter studies were performed on each configuration to gain insight in fluid flow, shear stress distribution and oxygen availability in the AMC-BAL. We assessed the function of the internal oxygenator, the effect of changes in hepatocyte oxygen consumption parameters in time and the effect of the change from an experimental to a clinical setting. In addition, different methodologies were studied to improve cellular oxygen availability, i.e. external oxygenation of culture medium, culture medium flow rate, culture gas oxygen content (pO(2)) and the number of oxygenation capillaries. Standard operating conditions did not adequately provide all hepatocytes in the AMC-BAL with sufficient oxygen to maintain O(2) consumption at minimally 90% of maximal uptake rate. Cellular oxygen availability was optimized by increasing the number of gas capillaries and pO(2) of the oxygenation gas by a factor two. Pressure drop over the AMC-BAL and maximal shear stresses were low and not considered to be harmful. This information can be used to increase cellular efficiency and may ultimately lead to a more productive AMC-BAL.
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Affiliation(s)
- Guy Mareels
- Cardiovascular Mechanics and Biofluid Dynamics Research Group, Institute of Biomedical Technology, Ghent University, 9000, Gent, Belgium.
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45
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Sharma NS, Shikhanovich R, Schloss R, Yarmush ML. Sodium butyrate-treated embryonic stem cells yield hepatocyte-like cells expressing a glycolytic phenotype. Biotechnol Bioeng 2006; 94:1053-63. [PMID: 16604521 DOI: 10.1002/bit.20936] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Embryonic stem cells serve as a promising technology to obtain specific cell types for a number of biomedical applications. Because traditional techniques, such as embryoid body formation result in a wide array of differentiated cells such as hepatic, neuronal, and cardiac lineages, strategies have been utilized which favor cell-specific differentiation to generate more uniformity. In the present study, we have investigated the use of sodium butyrate in a monolayer culture configuration to mediate hepatocyte differentiation of murine embryonic stem cells. Several functional assays used to characterize hepatocyte function (viz. urea secretion, intracellular albumin content, cytokeratin 18, and glycogen staining) were used to analyze the differentiating cell population, suggesting the presence of an enriched population of hepatocyte-like cells. Since mature hepatocytes mediate energy metabolism predominantly through oxidative means as opposed to hepatocyte precursors, which are primarily glycolytic, we have performed a kinetic analysis of glycolytic and functional capacity to characterize the differentiated cells. In conjunction with mitochondrial mass and activity measurements, we show that Na-butyrate-mediated differentiated cells mediate energy metabolism predominantly through glycolysis. This metabolic and mitochondrial characterization can assist in evaluating stem cell differentiation and may prove useful in identifying key regulatory molecules in mediating further differentiation.
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Affiliation(s)
- N S Sharma
- Department of Chemical & Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, New Jersey 08854, USA
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46
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Nahmias Y, Berthiaume F, Yarmush ML. Integration of technologies for hepatic tissue engineering. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2006; 103:309-29. [PMID: 17195468 DOI: 10.1007/10_029] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The liver is the largest internal organ in the body, responsible for over 500 metabolic, regulatory, and immune functions. Loss of liver function leads to liver failure which causes over 25,000 deaths/year in the United States. Efforts in the field of hepatic tissue engineering include the design of bioartificial liver systems to prolong patient's lives during liver failure, for drug toxicity screening and for the study of liver regeneration, ischemia/reperfusion injury, fibrosis, viral infection, and inflammation. This chapter will overview the current state-of-the-art in hepatology including isolated perfused liver, culture of liver slices and tissue explants, hepatocyte culture on collagen "sandwich" and spheroids, coculture of hepatocytes with non-parenchymal cells, and the integration of these culture techniques with microfluidics and reactor design. This work will discuss the role of oxygen and medium composition in hepatocyte culture and present promising new technologies for hepatocyte proliferation and function. We will also discuss liver development, architecture, and function as they relate to these culture techniques. Finally, we will review current opportunities and major challenges in integrating cell culture, bioreactor design, and microtechnology to develop new systems for novel applications.
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Affiliation(s)
- Yaakov Nahmias
- Center for Engineering in Medicine, Department of Surgery, Massachusetts General Hospital, Shriners Burns Hospital, Harvard Medical School, 51 Blossom St, Boston, MA 02114, USA
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47
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He X, Amin AA, Fowler A, Toner M. Thermally Induced Introduction of Trehalose into Primary Rat Hepatocytes. ACTA ACUST UNITED AC 2006. [DOI: 10.1089/cpt.2006.4.178] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Xiaoming He
- Center for Engineering in Medicine and Surgery Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Arthi A. Amin
- Center for Engineering in Medicine and Surgery Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Alex Fowler
- Department of Mechanical Engineering, University of Massachusetts at Dartmouth, North Dartmouth, Massachusetts
| | - Mehmet Toner
- Center for Engineering in Medicine and Surgery Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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48
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McGuigan AP, Sefton MV. Vascularized organoid engineered by modular assembly enables blood perfusion. Proc Natl Acad Sci U S A 2006; 103:11461-6. [PMID: 16864785 PMCID: PMC1544192 DOI: 10.1073/pnas.0602740103] [Citation(s) in RCA: 309] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tissue engineering is one approach to address the donor-organ shortage, but to attain clinically significant viable cell densities in thick tissues, laboratory-constructed tissues must have an internal vascular supply. We have adopted a biomimetic approach and assembled microscale modular components, consisting of submillimeter-sized collagen gel rods seeded with endothelial cells (ECs) into a (micro)vascularized tissue; in some prototypes the gel contained HepG2 cells to illustrate the possibilities. The EC-covered modules then were assembled into a larger tube and perfused with medium or whole blood. The interstitial spaces among the modules formed interconnected channels that enabled this perfusion. Viable cell densities were high, within an order of magnitude of cell densities within tissues, and the percolating nature of the flow through the construct was evident in microcomputed tomography and Doppler ultrasound measurements. Most importantly, the ECs retained their nonthrombogenic phenotype and delayed clotting times and inhibited the loss of platelets associated with perfusion of whole blood through the construct. Unlike the conventional scaffold and cell-seeding paradigm of other tissue-engineering approaches, this modular construct has the potential to be scalable, uniform, and perfusable with whole blood, circumventing the limitations of other approaches.
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Affiliation(s)
- Alison P. McGuigan
- Department of Chemical Engineering and Applied Chemistry and Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada M5S 3G9
| | - Michael V. Sefton
- Department of Chemical Engineering and Applied Chemistry and Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada M5S 3G9
- *To whom correspondence should be addressed. E-mail:
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49
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Cochran DM, Fukumura D, Ancukiewicz M, Carmeliet P, Jain RK. Evolution of oxygen and glucose concentration profiles in a tissue-mimetic culture system of embryonic stem cells. Ann Biomed Eng 2006; 34:1247-58. [PMID: 16832606 DOI: 10.1007/s10439-006-9134-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 05/09/2006] [Indexed: 10/24/2022]
Abstract
A tissue-mimetic culture system (TMCS) in which cells are sandwiched between two glass slides provides an ideal microenvironment for studying the effects of oxygen and nutrient gradients on cells in culture. A mathematical model was utilized to predict the time course of the development of oxygen and glucose concentration gradients within the TMCS. Oxygen and glucose consumption rates of mouse embryonic stem cells were measured as parameters for the model. The model predicts oxygen and glucose concentration profiles directly using a single experimentally controlled variable, the seeding density of cells within the system. The model predicts that the time required for the gradients to reach steady state is inversely related to the cell density, and the penetration depth of the gradients into the TMCS is inversely related to the square root of the cell density. Experimental oxygen concentration measurements were performed at a cell density of 9.1 x 10(6) cells cm(-3), and the gradient was found to develop to a steady-state profile within 20 min and penetrate approximately 2 mm into the TMCS, consistent with the theoretical predictions. This model and the TMCS provide useful tools for investigating the effect of the metabolic microenvironment on cells in culture.
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Affiliation(s)
- David M Cochran
- Edwin L. Steele Laboratory, Department of Radiation Oncology, Massachusetts General Hospital, 100 Blossom St, Cox-7, Boston, Massachusetts, 02114, USA
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50
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Novik EI, Maguire TJ, Orlova K, Schloss RS, Yarmush ML. Embryoid body-mediated differentiation of mouse embryonic stem cells along a hepatocyte lineage: insights from gene expression profiles. TISSUE ENGINEERING 2006; 12:1515-25. [PMID: 16846348 PMCID: PMC3199957 DOI: 10.1089/ten.2006.12.1515] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pluripotent embryonic stem (ES) cells represent a promising renewable cell source for the generation of functional differentiated cells. Previous studies incorporating embryoid body (EB)-mediated stem cell differentiation have, either spontaneously or after growth factor and extracellular matrix protein supplementation, yielded populations of hepatocyte lineage cells expressing mature hepatocyte markers such as albumin (ALB). In an effort to promote ES cell commitment to the hepatocyte lineage, we have evaluated the effects of four culture conditions on albumin and gene expression in differentiating ES cells. Quantitative in situ immunofluorescence and cDNA microarray analyses were used to describe not only lineage specificity but also to provide insights into the effects of disparate culture environments on the mechanisms of differentiation. The results of these studies suggest that spontaneous and collagen-mediated differentiation induce cells with the highest levels of ALB expression but mature liver specific genes were only expressed in the spontaneous condition. Further analysis of gene expression profiles indicated that two distinct mechanisms may govern spontaneous and collagen-mediated differentiation.
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Affiliation(s)
- Eric I Novik
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey, USA
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