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Difference in pyruvic acid metabolism between neonatal and adult mouse lungs exposed to hyperoxia. PLoS One 2020; 15:e0238604. [PMID: 32881962 PMCID: PMC7470327 DOI: 10.1371/journal.pone.0238604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/19/2020] [Indexed: 11/19/2022] Open
Abstract
Objective Neonatal lungs are more tolerant to hyperoxic injury than are adult lungs. This study investigated differences in the response to hyperoxic exposure between neonatal and adult mouse lungs using metabolomics analysis with capillary electrophoresis time-of-flight mass spectrometry (CE- TOFMS). Methods Neonatal and adult mice were exposed to 21% or 95% O2 for four days. Subsequently, lung tissue samples were collected and analyzed by CE-TOFMS. Pyruvate dehydrogenase (PDH) enzyme activity was determined using a microplate assay kit. PDH kinase (Pdk) 1, Pdk2, Pdk3, and Pdk4 mRNA expression levels were determined using quantitative reverse transcription-polymerase chain reaction. Pdk4 protein expression was quantified by Western blotting and Pdk4 protein localization was evaluated by immunohistochemistry. Results Levels of 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvic acid, and lactic acid were significantly elevated in the lungs of hyperoxia-exposed versus normoxia-exposed adult mice, whereas no significant differences were observed with hyperoxia exposure in neonatal mice. PDH activity was reduced in the lungs of adult mice only. Pdk4 mRNA expression levels after hyperoxic exposure were significantly elevated in adult mice compared with that in neonatal mice. Conversely, gene expression levels of Pdk1, Pdk2, and Pdk3 did not differ after hyperoxic exposure in either neonatal or adult mice. Pdk4 protein levels were also significantly increased in adult mouse lungs exposed to hyperoxia and were localized mainly to the epithelium of terminal bronchiole. Conclusions Specific metabolites associated with glycolysis and gluconeogenesis were altered after hyperoxia exposure in the lungs of adult mice, but not in neonates, which was likely a result of reduced PDH activity due to Pdk4 mRNA upregulation under hyperoxia.
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Burova I, Wall I, Shipley RJ. Mathematical and computational models for bone tissue engineering in bioreactor systems. J Tissue Eng 2019; 10:2041731419827922. [PMID: 30834100 PMCID: PMC6391543 DOI: 10.1177/2041731419827922] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 01/01/2019] [Indexed: 01/13/2023] Open
Abstract
Research into cellular engineered bone grafts offers a promising solution to problems associated with the currently used auto- and allografts. Bioreactor systems can facilitate the development of functional cellular bone grafts by augmenting mass transport through media convection and shear flow-induced mechanical stimulation. Developing successful and reproducible protocols for growing bone tissue in vitro is dependent on tuning the bioreactor operating conditions to the specific cell type and graft design. This process, largely reliant on a trial-and-error approach, is challenging, time-consuming and expensive. Modelling can streamline the process by providing further insight into the effect of the bioreactor environment on the cell culture, and by identifying a beneficial range of operational settings to stimulate tissue production. Models can explore the impact of changing flow speeds, scaffold properties, and nutrient and growth factor concentrations. Aiming to act as an introductory reference for bone tissue engineers looking to direct their experimental work, this article presents a comprehensive framework of mathematical models on various aspects of bioreactor bone cultures and overviews modelling case studies from literature.
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Affiliation(s)
- Iva Burova
- Department of Mechanical Engineering, University College London (UCL), London, UK
| | - Ivan Wall
- Aston Medical Research Institute and School of Life & Health Sciences, Aston University, Birmingham, UK
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, Republic of Korea
| | - Rebecca J Shipley
- Department of Mechanical Engineering, University College London (UCL), London, UK
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3
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Al-Ani A, Toms D, Kondro D, Thundathil J, Yu Y, Ungrin M. Oxygenation in cell culture: Critical parameters for reproducibility are routinely not reported. PLoS One 2018; 13:e0204269. [PMID: 30325922 PMCID: PMC6191109 DOI: 10.1371/journal.pone.0204269] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/04/2018] [Indexed: 01/01/2023] Open
Abstract
Mammalian cell culture is foundational to biomedical research, and the reproducibility of research findings across the sciences is drawing increasing attention. While many components contribute to reproducibility, the reporting of factors that impact oxygen delivery in the general biomedical literature has the potential for both significant impact, and immediate improvement. The relationship between the oxygen consumption rate of cells and the diffusive delivery of oxygen through the overlying medium layer means parameters such as medium depth and cell type can cause significant differences in oxygenation for cultures nominally maintained under the same conditions. While oxygenation levels are widely understood to significantly impact the phenotype of cultured cells in the abstract, in practise the importance of the above parameters does not appear to be well recognized in the non-specialist research community. On analyzing two hundred articles from high-impact journals we find a large majority missing at least one key piece of information necessary to ensure consistency in replication. We propose that explicitly reporting these values should be a requirement for publication.
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Affiliation(s)
- Abdullah Al-Ani
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Derek Toms
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Douglas Kondro
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Jarin Thundathil
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Yang Yu
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Mark Ungrin
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
- * E-mail:
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4
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Catapano G. Mass Transfer Limitations to the Performance of Membrane Bioartificial Liver Support Devices. Int J Artif Organs 2018. [DOI: 10.1177/039139889601900105] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A number of membrane bioartificial devices have been proposed for liver support. However, their design does not yet ensure the successful treatment of acute liver insufficiency. In this paper, the Author reviews the limitations of the mass transport phenomena to the performance of a membrane bioartificial liver support device. First of all the requirements that an optimal membrane bioartificial liver support device has to meet for the therapy to be effective are presented. On these grounds, the issues that are still to be addressed to optimize the performance of such devices are discussed: particular attention is devoted to the mass transport phenomena in each region of the membrane bioartificial device. Finally, the main transport features of the membrane bioartificial liver support devices proposed so far are illustrated and examined.
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Affiliation(s)
- G. Catapano
- Department of Chemical and Materials Engineering, University of Calabria, Arcavacata di Rende (CS) - Italy
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5
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Tiwari A, Wong CS, Nekkanti LP, Deane JA, McDonald C, Li J, Pham Y, Sutherland AE, Jenkin G, Kirkland MA. Controlling the Effective Oxygen Tension Experienced by Cells Using a Dynamic Culture Technique for Hematopoietic Ex Vivo Expansion. ACTA ACUST UNITED AC 2018; 44:2A.11.1-2A.11.13. [PMID: 29512129 DOI: 10.1002/cpsc.42] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Clinical hematopoietic stem/progenitor cell (HSPC) transplantation outcomes are strongly correlated with the number of cells infused. Hence, to generate sufficient HSPCs for transplantation, the best culture parameters for expansion are critical. It is generally assumed that the defined oxygen (O2 ) set for the incubator reflects the pericellular O2 to which cells are being exposed. Studies have shown that low O2 tension maintains an undifferentiated state, but the expansion rate may be constrained because of limited diffusion in a static culture system. A combination of low ambient O2 and dynamic culture conditions has been developed to increase the reconstituting capacity of human HSPCs. In this unit, the protocols for serum-free expansion of HSPCs at 5% and 20% O2 in static and dynamic nutrient flow mode are described. Finally, the impact of O2 tension on HSPC expansion in vitro by flow cytometry and colony forming assays and in vivo through engraftment using a murine model is assessed. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Abhilasha Tiwari
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Cynthia S Wong
- Institute for Frontier Materials, Deakin University, Geelong, Victoria, Australia
| | - Lakshmi P Nekkanti
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - James A Deane
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Courtney McDonald
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Jingang Li
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Yen Pham
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Amy E Sutherland
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Graham Jenkin
- The Ritchie Centre, Hudson Institute of Medical Research, Department of Obstetrics & Gynaecology, Southern Clinical School, Monash University, Clayton, Victoria, Australia
| | - Mark A Kirkland
- Institute for Frontier Materials, Deakin University, Geelong, Victoria, Australia
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Patrick A, Seluanov M, Hwang C, Tam J, Khan T, Morgenstern A, Wiener L, Vazquez JM, Zafar H, Wen R, Muratkalyeva M, Doerig K, Zagorulya M, Cole L, Catalano S, Lobo Ladd AA, Coppi AA, Coşkun Y, Tian X, Ablaeva J, Nevo E, Gladyshev VN, Zhang ZD, Vijg J, Seluanov A, Gorbunova V. Sensitivity of primary fibroblasts in culture to atmospheric oxygen does not correlate with species lifespan. Aging (Albany NY) 2017; 8:841-7. [PMID: 27163160 PMCID: PMC4931838 DOI: 10.18632/aging.100958] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/26/2016] [Indexed: 01/01/2023]
Abstract
Differences in the way human and mouse fibroblasts experience senescence in culture had long puzzled researchers. While senescence of human cells is mediated by telomere shortening, Parrinello et al. demonstrated that senescence of mouse cells is caused by extreme oxygen sensitivity. It was hypothesized that the striking difference in oxygen sensitivity between mouse and human cells explains their different rates of aging. To test if this hypothesis is broadly applicable, we cultured cells from 16 rodent species with diverse lifespans in 3% and 21% oxygen and compared their growth rates. Unexpectedly, fibroblasts derived from laboratory mouse strains were the only cells demonstrating extreme sensitivity to oxygen. Cells from hamster, muskrat, woodchuck, capybara, blind mole rat, paca, squirrel, beaver, naked mole rat and wild-caught mice were mildly sensitive to oxygen, while cells from rat, gerbil, deer mouse, chipmunk, guinea pig and chinchilla showed no difference in the growth rate between 3% and 21% oxygen. We conclude that, although the growth of primary fibroblasts is generally improved by maintaining cells in 3% oxygen, the extreme oxygen sensitivity is a peculiarity of laboratory mouse strains, possibly related to their very long telomeres, and fibroblast oxygen sensitivity does not directly correlate with species' lifespan.
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Affiliation(s)
- Alison Patrick
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Michael Seluanov
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Chaewon Hwang
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Jonathan Tam
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Tanya Khan
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Ari Morgenstern
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Lauren Wiener
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Juan M Vazquez
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Hiba Zafar
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Robert Wen
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | | | - Katherine Doerig
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Maria Zagorulya
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Lauren Cole
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Sophia Catalano
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Aliny Ab Lobo Ladd
- Laboratory of Stochastic Stereology and Chemical Anatomy (LSSCA), Department of Surgery, College of Veterinary Medicine and Animal Science, University of São Paulo (USP), São Paulo, Brazil
| | - A Augusto Coppi
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Yüksel Coşkun
- Science Faculty, Biology Department, Dicle University, 21280 Diyarbakır, Turkey
| | - Xiao Tian
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Julia Ablaeva
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Eviatar Nevo
- Institute of Evolution, University of Haifa, Haifa 31905, Israel
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Zhengdong D Zhang
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andrei Seluanov
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Vera Gorbunova
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
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Xu S, Hoshan L, Jiang R, Gupta B, Brodean E, O'Neill K, Seamans TC, Bowers J, Chen H. A practical approach in bioreactor scale-up and process transfer using a combination of constant P/V and vvm as the criterion. Biotechnol Prog 2017; 33:1146-1159. [PMID: 28440060 DOI: 10.1002/btpr.2489] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 04/13/2017] [Indexed: 11/06/2022]
Abstract
Bioreactor scale-up is a critical step in the production of therapeutic proteins such as monoclonal antibodies (MAbs). With the scale-up criterion such as similar power input per volume or O2 volumetric mass transfer coefficient ( kLa), adequate oxygen supply and cell growth can be largely achieved. However, CO2 stripping in the growth phase is often inadequate. This could cascade down to increased base addition and osmolality, as well as residual lactate increase and compromised production and product quality. Here we describe a practical approach in bioreactor scale-up and process transfer, where bioreactor information may be limited. We evaluated the sparger kLa and kLaCO2 (CO2 volumetric mass transfer coefficient) from a range of bioreactor scales (3-2,000 L) with different spargers. Results demonstrated that kLa for oxygen is not an issue when scaling from small-scale to large-scale bioreactors at the same gas flow rate per reactor volume (vvm). Results also showed that sparging CO2 stripping, kLaCO2, is dominated by the gas throughput. As a result, a combination of a minimum constant vvm air or N2 flow with a similar specific power was used as the general scale-up criterion. An equation was developed to determine the minimum vvm required for removing CO2 produced from cell respiration. We demonstrated the effectiveness of using such scale-up criterion with five MAb projects exhibiting different cell growth and metabolic characteristics, scaled from 3 to 2,000 L bioreactors across four sites. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1146-1159, 2017.
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Affiliation(s)
- Sen Xu
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Linda Hoshan
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Rubin Jiang
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Balrina Gupta
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Eric Brodean
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Kristin O'Neill
- BioProcess Technical Operations, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - T Craig Seamans
- BioProcess Technical Operations, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - John Bowers
- BioProcess Technical Operations, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
| | - Hao Chen
- Process Development and Engineering, Biologics & Vaccines, Merck & Co., Inc., Kenilworth, NJ, 07033
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8
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Tiwari A, Wong CS, Nekkanti LP, Deane JA, McDonald C, Jenkin G, Kirkland MA. Impact of Oxygen Levels on Human Hematopoietic Stem and Progenitor Cell Expansion. Stem Cells Dev 2016; 25:1604-1613. [PMID: 27539189 DOI: 10.1089/scd.2016.0153] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Oxygen levels are an important variable during the in vitro culture of stem cells. There has been increasing interest in the use of low oxygen to maximize proliferation and, in some cases, effect differentiation of stem cell populations. It is generally assumed that the defined pO2 in the incubator reflects the pO2 to which the stem cells are being exposed. However, we demonstrate that the pO2 experienced by cells in static culture can change dramatically during the course of culture as cell numbers increase and as the oxygen utilization by cells exceeds the diffusion of oxygen through the media. Dynamic culture (whereby the cell culture plate is in constant motion) largely eliminates this effect, and a combination of low ambient oxygen and dynamic culture results in a fourfold increase in reconstituting capacity of human hematopoietic stem cells compared with those cultured in static culture at ambient oxygen tension. Cells cultured dynamically at 5% oxygen exhibited the best expansion: 30-fold increase by flow cytometry, 120-fold increase by colony assay, and 11% of human CD45 engraftment in the bone marrow of NOD/SCID mice. To our knowledge, this is the first study to compare individual and combined effects of oxygen and static or dynamic culture on hematopoietic ex vivo expansion. Understanding and controlling the effective oxygen tension experienced by cells may be important in clinical stem cell expansion systems, and these results may have relevance to the interpretation of low oxygen culture studies.
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Affiliation(s)
- Abhilasha Tiwari
- 1 The Ritchie Centre, Hudson Institute of Medical Research , Clayton, Australia
| | | | - Lakshmi P Nekkanti
- 1 The Ritchie Centre, Hudson Institute of Medical Research , Clayton, Australia
| | - James A Deane
- 1 The Ritchie Centre, Hudson Institute of Medical Research , Clayton, Australia .,3 Department of Obstetrics and Gynaecology, Southern Clinical School, Monash University , Clayton, Australia
| | - Courtney McDonald
- 1 The Ritchie Centre, Hudson Institute of Medical Research , Clayton, Australia
| | - Graham Jenkin
- 1 The Ritchie Centre, Hudson Institute of Medical Research , Clayton, Australia .,3 Department of Obstetrics and Gynaecology, Southern Clinical School, Monash University , Clayton, Australia
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Hyperoxia decreases glycolytic capacity, glycolytic reserve and oxidative phosphorylation in MLE-12 cells and inhibits complex I and II function, but not complex IV in isolated mouse lung mitochondria. PLoS One 2013; 8:e73358. [PMID: 24023862 PMCID: PMC3759456 DOI: 10.1371/journal.pone.0073358] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 07/26/2013] [Indexed: 01/01/2023] Open
Abstract
High levels of oxygen (hyperoxia) are frequently used in critical care units and in conditions of respiratory insufficiencies in adults, as well as in infants. However, hyperoxia has been implicated in a number of pulmonary disorders including bronchopulmonary dysplasia (BPD) and adult respiratory distress syndrome (ARDS). Hyperoxia increases the generation of reactive oxygen species (ROS) in the mitochondria that could impair the function of the mitochondrial electron transport chain. We analyzed lung mitochondrial function in hyperoxia using the XF24 analyzer (extracellular flux) and optimized the assay for lung epithelial cells and mitochondria isolated from lungs of mice. Our data show that hyperoxia decreases basal oxygen consumption rate (OCR), spare respiratory capacity, maximal respiration and ATP turnover in MLE-12 cells. There was significant decrease in glycolytic capacity and glycolytic reserve in MLE-12 cells exposed to hyperoxia. Using mitochondria isolated from lungs of mice exposed to hyperoxia or normoxia we have shown that hyperoxia decreased the basal, state 3 and state3 μ (respiration in an uncoupled state) respirations. Further, using substrate or inhibitor of a specific complex we show that the OCR via complex I and II, but not complex IV was decreased, demonstrating that complexes I and II are specific targets of hyperoxia. Further, the activities of complex I (NADH dehydrogenase, NADH-DH) and complex II (succinate dehydrogenase, SDH) were decreased in hyperoxia, but the activity of complex IV (cytochrome oxidase, COX) remains unchanged. Taken together, our study show that hyperoxia impairs glycolytic and mitochondrial energy metabolism in in tact cells, as well as in lungs of mice by selectively inactivating components of electron transport system.
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Metabolic changes during cellular senescence investigated by proton NMR-spectroscopy. Mech Ageing Dev 2013; 134:130-8. [PMID: 23416267 DOI: 10.1016/j.mad.2013.02.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/10/2012] [Accepted: 02/02/2013] [Indexed: 11/21/2022]
Abstract
Cellular senescence is of growing interest due to its role in tumour suppression and its contribution to organismic ageing. This cellular state can be reached by replicative loss of telomeres or certain stresses in cell culture and is characterized by the termination of cell division; however, the cells remain metabolically active. To identify metabolites that are characteristic for senescent cells, extracts of human embryonic lung fibroblast (WI-38 cell line) have been investigated with NMR spectroscopy. Three different types of senescence have been characterized: replicative senescence, DNA damage-induced senescence (etoposide treatment) and oncogene-induced senescence (hyperactive RAF kinase). The metabolite pattern allows (I) discrimination of senescent and control cells and (II) discrimination of the three senescence types. Senescent cells show an increased ratio of glycerophosphocholine to phosphocholine independent from the type of senescence. The increase in glycerophosphocholine implicates a key role of phospholipid metabolism in cellular senescence. The observed changes in the choline metabolism are diametrically opposite to the well-known changes in choline metabolism of tumour cells. As tumours responding to chemotherapeutic agents show a "glycerophosphocholine-to-phosphocholine switch" i.e. an increase in glycerophosphocholine, our metabolic data suggests that these malignant cells enter a senescent state emphasizing the role of senescence in tumour suppression.
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Balin AK, Reimer RJ, Reenstra WR, Lilie SM, Leong I, Sullivan K, Allen RG. Effects of oxygen, growth state, and senescence on the antioxidant responses of WI-38 fibroblasts. AGE (DORDRECHT, NETHERLANDS) 2010; 32:435-449. [PMID: 20473639 PMCID: PMC2980593 DOI: 10.1007/s11357-010-9149-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 04/26/2010] [Indexed: 05/29/2023]
Abstract
Mitotically active, growth-arrested cells and proliferatively senescent cultures of human fetal lung fibroblasts (WI-38) were exposed to six different oxygen tensions for various lengths of time and then analyzed to determine the responses of their antioxidant defense system. Glutathione (GSH) concentration increased as a function of ambient oxygen tension in early passage cultures; the effect was larger in exponentially growing cultures than in those in a state of contact-inhibited growth arrest, but was absent in senescent cells. Conversely, the activity of glutathione disulfide reductase was greater in growth-arrested cultures than in mitotically active cells irrespective of oxygen tension. Glucose-6-phosphate dehydrogenase was lowest in log-phase cells exposed to different oxygen tensions for 24 h and in senescent cells. Both hypoxia and hyperoxia depressed selenium-dependent glutathione peroxidase activity in early passage cultures, while the activity of the enzyme progressively declined with increasing oxygen in senescent cells. The GSH S-transferase activity was unresponsive to changes in ambient oxygen tension in either young or senescent cultures. Manganese-containing superoxide dismutase (MnSOD) activity was unaffected by oxygen tension, but was elevated in young confluent cultures as compared with cultures in log-phase growth. MnSOD activity was significantly higher in senescent cultures than in early passage cultures and was also responsive to increased oxygen tension in senescent cultures. Copper-zinc-containing superoxide dismutases activity was not affected by oxygen tension or the passage of time, but it declined in senescent cultures.
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Affiliation(s)
- Arthur K Balin
- Laboratory for Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
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12
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Jan DC, Petch DA, Huzel N, Butler M. The effect of dissolved oxygen on the metabolic profile of a murine hybridoma grown in serum-free medium in continuous culture. Biotechnol Bioeng 2009; 54:153-64. [PMID: 18634083 DOI: 10.1002/(sici)1097-0290(19970420)54:2<153::aid-bit7>3.0.co;2-k] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The murine B-lymphocyte hybridoma, CC9C10 was grown at steady state under serum-free conditions in continuous culture at dissolved oxygen (DO) concentrations in the range of 10% to 150% of air saturation. Cells could be maintained with this range at high viability in a steady state at a dilution rate of 1 d(-1), although with lower cell concentrations at higher DO. A higher specific antibody production measured at higher DO was matched by a decrease in the viable cell concentration at steady state, so that the volumetric antibody titre was not changed significantly. An attempt to grow cells at 250% of air saturation was unsuccessful but the cells recovered to normal growth once the DO was decreased.There was a requirement for cellular adaptation at each step-wise increase in dissolved oxygen. Adaptation to a DO of 100% was associated with an increase in the specific activities of glutathione peroxidase (x18), glutathione S-transferase (x11) and superoxide dismutase (x6) which are all known antioxidant enzymes. At DO above 100%, the activities of GPX and GST decreased possibly as a result of inactivation by reactive oxygen radicals.The increase in dissolved oxygen concentration caused changes in energy metabolism. The specific rate of glucose uptake increased at higher dissolved oxygen concentrations with a higher proportion of glucose metabolized anaerobically. Short-term radioactive assays showed that the relative flux of glucose through glycolysis and the pentose phosphate pathway increased whereas the flux through the tricarboxylic acid cycle decreased at high DO. Although the specific glutamine utilization rate increased at higher DO, there was no evidence for a change in the pattern of metabolism. This indicates a possible blockage of glycolytic metabolites into the TCA cycle, and is compatible with a previous suggestion that pyruvate dehydrogenase is inhibited by high oxygen concentrations.Analysis of the oxygen uptake rate of cell suspensions at steady state under all conditions showed a pronounced Crabtree effect which was manifest by a decrease (up to 40%) in oxygen consumption on addition of glucose. This indicates that the degree of aerobic metabolism in these cultures is highly sensitive to the glucose concentration.
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Affiliation(s)
- D C Jan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
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Huang L, Estrada R, Yappert MC, Borchman D. Oxidation-induced changes in human lens epithelial cells. 1. Phospholipids. Free Radic Biol Med 2006; 41:1425-32. [PMID: 17023269 DOI: 10.1016/j.freeradbiomed.2006.07.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 06/22/2006] [Accepted: 07/31/2006] [Indexed: 11/17/2022]
Abstract
Lipid compositional changes in lens epithelial cells (HLE B-3) grown in a hyperoxic atmosphere were studied to determine if oxidation could cause changes in the amount and type of phospholipid similar to those found in vivo with age and cataract. The phosphatidylcholines in HLE B-3 cells were 8 times more unsaturated than the sphingomyelins. Cell viability was the same for cells grown for up to 48 h in a normoxic or hyperoxic atmosphere. Lipid oxidation was about three times higher after growth in a hyperoxic atmosphere compared with cells grown in a normoxic atmosphere. The lack of change in the relative amount of sphingomyelin and the decrease in phosphatidylcholine coupled with the increase in lysophosphatidylcholine support the idea that similar mechanisms may be responsible for the lipid compositional changes in both lens epithelial and fiber cells. It is postulated that lipases eliminate oxidized unsaturated glycerolipids, leaving a membrane increasingly composed of more ordered and more saturated sphingolipids. Oxidative stress leads to changes in membrane composition that are consistent with those seen with age in human epithelial cells. Oxidation-induced epithelial phospholipid change is an area of research that has gone virtually unexplored in the human lens and could be relevant to all cell types and may be important to lens clarity.
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Affiliation(s)
- Li Huang
- Department of Ophthalmology and Visual Science, University of Louisville, University of Louisville, Louisville, KY 40202, USA
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14
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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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15
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Butler M. Growth limitations in microcarrier cultures. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2005; 34:57-84. [PMID: 3113184 DOI: 10.1007/bfb0000673] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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16
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Padgaonkar VA, Leverenz VR, Dang L, Chen SC, Pelliccia S, Giblin FJ. Thioredoxin reductase may be essential for the normal growth of hyperbaric oxygen-treated human lens epithelial cells. Exp Eye Res 2005; 79:847-57. [PMID: 15642322 DOI: 10.1016/j.exer.2004.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Accepted: 07/05/2004] [Indexed: 10/26/2022]
Abstract
We have shown previously with in vivo and in vitro animal models that the lens epithelium, in contrast to the nucleus, is remarkably resistant to hyperoxia. The main purpose of this study was to investigate the mRNA response of cultured human lens epithelial cells (LECs) to challenge by a high level of hyperbaric oxygen. Cells were treated for 3 hr with 50 atm of 99% O2, and then cultured normally for various times up to 11 days. Although the cells appeared normal immediately after the O2-treatment, they failed to grow and suffered 50% cell loss, as well as significant mitochondrial damage, during normal post-culture. Growth of the cells resumed after 3 days and by day 11, the number of O2-treated cells was the same as the controls. Remarkably, the 3 hr O2-treatment produced no immediate effects on either the cellular level of GSH, or on the activities of a number of antioxidant enzymes including glyceraldehyde-3-phosphate dehydrogenase, which is generally regarded as being highly sensitive to oxidation. In contrast, the activity of thioredoxin reductase (TrxR) was severely affected by the O2, decreasing by 51% after the 3 hr exposure. O2-induced death of the cells appeared to be caused by loss of ATP since a 31% decrease in ATP level occurred immediately after the O2-treatment, in spite of a 46% increase in lactate production. Analysis with real-time PCR showed a maximum 3-6-fold increase in mRNA levels 9 hr after the 3 hr O2-exposure for the enzymes heme oxygenase-1 (HO-1), MnSOD and TrxR1 (the cytoplasmic form of TrxR). These results were confirmed with the use of one-step RT-PCR and Northern blotting. Initial upregulation of message for HO-1 occurred a few hours before any upregulation of MnSOD could be detected, suggesting that release of free iron from the degradation of heme by HO-1 may have played a role in the upregulation of the dismutase. No significant changes in mRNA levels were observed for the antioxidant enzymes catalase, CuZnSOD, glutathione reductase and glutathione peroxidase, or for the antioxidant protein thioredoxin. Recovery of TrxR activity over a 4-day period appeared to parallel the return of the cells to a normal rate of growth. The results indicate that damaging effects of hyperoxia on cultured LECs occur primarily in the mitochondria, rather than in the cytoplasm. Cells avoid O2-induced cell death, and return to a normal rate of proliferation by upregulating mRNA levels for HO-1, MnSOD and TrxR1. It appears that full activity of TrxR1, an enzyme required for the production of deoxyribonucletides for DNA synthesis, is essential for the normal growth of O2-challenged LECs.
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Affiliation(s)
- Vanita A Padgaonkar
- Eye Research Institute, Oakland University, 412 Dodge Hall, Rochester, MI 48309-4480, USA
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17
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Shenberger JS, Myers JL, Zimmer SG, Powell RJ, Barchowsky A. Hyperoxia alters the expression and phosphorylation of multiple factors regulating translation initiation. Am J Physiol Lung Cell Mol Physiol 2004; 288:L442-9. [PMID: 15542544 PMCID: PMC2675186 DOI: 10.1152/ajplung.00127.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyperoxia is cytotoxic and depresses many cellular metabolic functions including protein synthesis. Translational control is exerted primarily during initiation by two mechanisms: 1) through inhibition of translation initiation complex formation via sequestration of the cap-binding protein, eukaryotic initiation factor (eIF) 4E, with inhibitory 4E-binding proteins (4E-BP); and 2) by prevention of eIF2-GTP-tRNA(i)(Met) formation and eIF2B activity by phosphorylated eIF2alpha. In this report, exposure of human lung fibroblasts to 95% O2 decreased the incorporation of thymidine into DNA at 6 h and the incorporation of leucine into protein beginning at 12 h. The reductions in DNA and protein synthesis were accompanied by increased phosphorylation of eIF4E protein and reduced phosphorylation of 4E-BP1. At 24 h, hyperoxia shifted 4E-BP1 phosphorylation to lesser-phosphorylated isoforms, increased eIF4E expression, and increased the association of eIF4E with 4E-BP1. Although hyperoxia did not change eIF2alpha expression, it increased its phosphorylation at Ser51, but not until 48 h. In addition, the activation of eIF2alpha was not accompanied by the formation of stress granules. These findings suggest that hyperoxia diminishes protein synthesis by increasing eIF4E phosphorylation and enhancing the affinity of 4E-BP1 for eIF4E.
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Affiliation(s)
- Jeffrey S Shenberger
- Department of Pediatrics, Dartmouth Medical School, Hanover, New Hampshire, USA.
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18
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Cristofalo VJ, Lorenzini A, Allen RG, Torres C, Tresini M. Replicative senescence: a critical review. Mech Ageing Dev 2004; 125:827-48. [PMID: 15541776 DOI: 10.1016/j.mad.2004.07.010] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human cells in culture have a limited proliferative capacity. After a period of vigorous proliferation, the rate of cell division declines and a number of changes occur in the cells including increases in size, in secondary lysosomes and residual bodies, nuclear changes and a number of changes in gene expression which provide biomarkers for senescence. Although human cells in culture have been used for over 40 years as models for understanding the cellular basis of aging, the relationship of replicative senescence to aging of the organism is still not clear. In this review, we discuss replicative senescence in the light of current information on signal transduction and mitogenesis, cell stress, apoptosis, telomere changes and finally we discuss replicative senescence as a model of aging in vivo.
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Affiliation(s)
- Vincent J Cristofalo
- The Lankenau Institute for Medical Research, 100 Lancaster Avenue, Wynnewood, PA 19096, USA.
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19
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Link T, Bäckström M, Graham R, Essers R, Zörner K, Gätgens J, Burchell J, Taylor-Papadimitriou J, Hansson GC, Noll T. Bioprocess development for the production of a recombinant MUC1 fusion protein expressed by CHO-K1 cells in protein-free medium. J Biotechnol 2004; 110:51-62. [PMID: 15099905 DOI: 10.1016/j.jbiotec.2003.12.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Revised: 11/20/2003] [Accepted: 12/19/2003] [Indexed: 11/19/2022]
Abstract
The mucin MUC1 is a candidate for use in specific immunotherapy against breast cancer, but this requires the large-scale production of a MUC1 antigen. In this study, a bioprocess for the expression of a recombinant MUC1 fusion protein with a cancer associated glycosylation in CHO-K1 cells has been developed. Cells permanently expressing parts of the extracellular portion of MUC1 fused to IgG Fc were directly transferred from adherent growth in serum-containing medium to suspension culture in the protein-free ProCHO4-CDM culture medium. Using the Cellferm-pro system, optimal culture parameter as pH and pO(2) were determined in parallel spinner flask batch cultures. A pH of 6.8-7.0 and a pO(2) of 40% of air saturation was found to give best cell growth and productivity of secreted recombinant protein. Specific productivity strongly depended the pO(2) and correlated with the online monitored oxygen uptake rate (OUR) of the cells, which indicates a positive influence of the rate of oxidative phosphorylation on productivity. The optimised conditions were applied to continuous perfusion culture which gave very high cell densities and space time yields of the recombinant MUC1 fusion protein, allowing production at gram scale. The product degradation was much lower in supernatants from continuous perfusion culture compared to batch mode. Antibodies reacting with cancer associated MUC1 glycoforms strongly bound to the fusion protein, indicating that the desired glycoforms were obtained and suggesting that the recombinant MUC1 protein could be tested for use in immunotherapy.
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Affiliation(s)
- T Link
- Institut für Biotechnologie 2, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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20
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Ogunlesi F, Cho C, McGrath-Morrow SA. The effect of glutamine on A549 cells exposed to moderate hyperoxia. Biochim Biophys Acta Mol Basis Dis 2004; 1688:112-20. [PMID: 14990341 DOI: 10.1016/j.bbadis.2003.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2003] [Revised: 10/27/2003] [Accepted: 10/31/2003] [Indexed: 11/22/2022]
Abstract
The use of high oxygen concentrations is frequently necessary in the treatment of acute respiratory distress syndrome (ARDS) and bronchopulmonary dysplasia (BPD). High oxygen concentrations, however, are detrimental to cell growth and cell survival. Glutamine (Gln) may be protective to cells during periods of stress and recently has been shown to increase survival in A549 cells exposed to lethal concentrations of oxygen (95% O2). We found that supplemental Gln enhances cell growth in A549 cells exposed to moderate concentrations of oxygen (60% O2). We therefore evaluated the effect of moderate hyperoxia on the cell cycle distribution of A549 cells. At 48 h there was no significant difference in the cell cycle distribution between 2 mM Gln cells in 60% O2 and 2 mM cells in room air. Furthermore, 2 mM Gln cells in 60% O2 had stable protein levels of cyclin B1 consistent with ongoing cell proliferation. In contrast, at 48 h, cells not supplemented with glutamine (Gln-) in 60% O2 had evidence of growth arrest by both flow cytometry (increased percentage of G1 cells) and by decreased protein levels of cyclin B1. G1 growth arrest in the Gln- cells exposed to 60% O2 was not, however, associated with induction of p21 protein. At 72 and 96 h, Gln- cells in 60% O2, began to demonstrate a partial loss of G1 checkpoint regulation and an increase in apoptosis, indicating an increased sensitivity to oxygen toxicity. Glutathione (GSH) concentrations were then measured. 2 mM Gln cells in 60% O2 were found to have higher concentrations of GSH compared to Gln- cells in 60% O2, suggesting that Gln confers protection to the cell during exposure to hyperoxia through up-regulation of GSH. When cells in 60% O2 were given higher concentrations of Gln (5 and 10 mM), cell growth at 96 h was increased compared to cells grown in 2 mM Gln (P<0.04). Clonal survival was also increased in cells exposed 60% O2 and supplemented with higher concentrations of Gln compared to Gln- cells in 60% O2. These studies suggest that supplemental glutamine may improve cell growth and cell viability and therefore may be beneficial to the lung during exposure to moderate concentrations of supplemental oxygen.
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Affiliation(s)
- Folasade Ogunlesi
- Department of Pediatrics, Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins Medical Institutions, Park 316 N Wolfe St, Baltimore, MD 21287-2533, USA
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21
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22
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Cogo A, Napolitano G, Michoud MC, Barbon DR, Ward M, Martin JG. Effects of hypoxia on rat airway smooth muscle cell proliferation. J Appl Physiol (1985) 2003; 94:1403-9. [PMID: 12626471 DOI: 10.1152/japplphysiol.00363.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although it is well known that hypoxemia induces pulmonary vasoconstriction and vascular remodeling, due to the proliferation of both vascular smooth muscle cells and fibroblasts, the effects of hypoxemia on airway smooth muscle cells are not well characterized. The present study was designed to assess the in vitro effects of hypoxia (1 or 3% O(2)) on rat airway smooth muscle cell growth and response to mitogens (PDGF and 5-HT). Cell growth was assessed by cell counting and cell cycle analysis. Compared with normoxia (21% O(2)), there was a 42.2% increase in the rate of proliferation of cells exposed to 3% O(2) (72 h, P = 0.006), as well as an enhanced response to PDGF (13.9% increase; P = 0.023) and to 5-HT (17.2% increase; P = 0.039). Exposure to 1% O(2) (72 h) decreased cell proliferation by 21.0% (P = 0.017) and reduced the increase in cell proliferation induced by PGDF and 5-HT by 16.2 and 15.7%, respectively (P = 0.019 and P = 0.011). A significant inhibition in hypoxia-induced cell proliferation was observed after the administration of bisindolylmaleimide GF-109203X (a specific PKC inhibitor) or downregulation of PKC with PMA. Pretreatment with GF-109203X decreased proliferation by 21.5% (P = 0.004) and PMA by 31.5% (P = 0.005). These results show that hypoxia induces airway smooth muscle cell proliferation, which is at least partially dependent on PKC activation. They suggest that hypoxia could contribute to airway remodeling in patients suffering from chronic, severe respiratory diseases.
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Affiliation(s)
- A Cogo
- Meakins-Christie Laboratories and Montreal Chest Institute Research Center, McGill University, Montréal, Québec, Canada H2X 2P2
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23
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Abstract
Elevated oxygen tensions are inhibitory to the growth of skin fibroblasts. Skin fibroblasts grow better at oxygen tensions below 137 mm Hg regardless of seeding density. A wide range of oxygen tensions, including those in the physiological range, strongly modulate the growth of human skin fibroblasts. There were no significant differences between the responses of fetal and postnatal cell lines to changes in ambient oxygen tension. In all cases, higher oxygen tensions significantly impeded cell growth. Seeding cells at 10(4) cells/cm(2) afforded some protection from the deleterious effects of hyperoxia. Oxygen tensions exceeding the amount present in ambient room air also impeded cell growth at this higher seeding density, but the effect did not become significant until the oxygen partial pressure reached 241 mm Hg. At lower oxygen tensions, cells seeded at 10(3) cells/cm(2) grew more rapidly than did cells seeded at 10(4) cells/cm(2). These findings may have implications for the treatment of poorly healing wounds with hyperbaric oxygen.
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Affiliation(s)
- Arthur K Balin
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, New York 10021, USA.
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24
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Balin AK, Pratt L, Allen RG. Effects of ambient oxygen concentration on the growth and antioxidant defenses of of human cell cultures established from fetal and postnatal skin. Free Radic Biol Med 2002; 32:257-67. [PMID: 11827751 DOI: 10.1016/s0891-5849(01)00807-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Oxygen toxicity is believed to arise from changes in the rates at which cells generate reactive oxygen species (ROS). Sensitivity to hyperoxia has been postulated to depend on levels of antioxidant defense. Human cells obtained from fetal tissues have lower antioxidant defenses than those obtained from adult tissue. The present study was performed to determine whether the differences in fetal and adult antioxidant defense levels modulated their responses to changes in the ambient oxygen concentration. Our results demonstrate that oxygen modulates the proliferation of human fetal and adult skin fibroblasts in a similar fashion. In general, skin fibroblasts grew better at approximately 31 mm Hg, regardless of donor age. Manganese superoxide dismutase, catalase, and glutathione peroxidase activities were lower in fetal cells than in adult fibroblasts. Copper/zinc superoxide dismutase and glucose-6-phosphate dehydrogenase were similar in fetal and postnatal tissues and were unaltered appreciably by hyperoxic exposure. Glutathione concentration increased at higher oxygen tensions; however, the increase was much greater in fetal cells than in cultures derived from adult skin. These observations demonstrate that the capacity of fetal and adult cells to cope with oxidative stress, while similar, result from distinct mechanisms.
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25
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Allen CB, Schneider BK, White CW. Limitations to oxygen diffusion and equilibration in in vitro cell exposure systems in hyperoxia and hypoxia. Am J Physiol Lung Cell Mol Physiol 2001; 281:L1021-7. [PMID: 11557606 DOI: 10.1152/ajplung.2001.281.4.l1021] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure of cultured cells to changing gaseous environments is used as a model for understanding both the immediate and long-term effects of such exposures on lung cells in vivo. We conducted experiments with polystyrene tissue culture flasks and plates to determine the time course of changes in oxygen concentration occurring under in vitro conditions. Only a few minutes were required for the concentration of oxygen in the environmental chamber to reach equilibrium with that of the flushing gas. However, >3 h were required for the oxygen content in the medium in the tissue culture flasks and plates to achieve equilibrium. The low solubility of oxygen in aqueous solutions and the limited diffusion of oxygen through a boundary layer of gas above the medium are the major barriers to rapid oxygen transport into the culture medium. The delay in achieving the desired PO(2) within the culture medium limits the temporal precision of any assessment of the correlation of cellular events with the concentration of oxygen to which those cells are exposed.
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Affiliation(s)
- C B Allen
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
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26
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Chen QM. Replicative senescence and oxidant-induced premature senescence. Beyond the control of cell cycle checkpoints. Ann N Y Acad Sci 2000; 908:111-25. [PMID: 10911952 DOI: 10.1111/j.1749-6632.2000.tb06640.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Normal human diploid fibroblasts (HDFs) undergo replicative senescence inevitably in tissue culture after a certain number of cell divisions. A number of molecular changes observed in replicative senescent cells occur in somatic cells during the process of aging. Genetic studies on replicative senescence indicate the control of tumor suppression mechanisms. Despite the significance of replicative senescence in aging and cancer, little is known about the central cause of the complex changes observed in replicative senescent cells. The interest in the phenomenon has intensified in recent years, since damaging agents, certain oncogenes and tumor suppressor genes have been found to induce features of senescence in early passage young HDFs or in immortalized tumor cells. The reported features of senescence are summarized here in order to clarify the concept of replicative senescence or premature senescence. The experimental results of extending the replicative life span by reducing ambient oxygen tension or by N-tert-butyl-alpha-phenylnitrone (PBN) argue a role of oxidative damage in replicative senescence. By inducing premature senescence with a pulse treatment of H2O2, we can study the role of the cell cycle checkpoint proteins p53, p21, p16 and Rb in gaining each feature of senescence. Although p53 and Rb control G1 arrest and Rb appears to control cell enlargement, activation of the senescent associate beta-galactosidase, loss of cell replication and multiple molecular changes observed in premature senescent or replicative senescent cells are likely controlled by mechanisms beyond the cell cycle checkpoints.
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Affiliation(s)
- Q M Chen
- Department of Pharmacology, University of Arizona, Tucson 85721, USA.
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27
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Kalns JE, Piepmeier EH. Exposure to hyperbaric oxygen induces cell cycle perturbation in prostate cancer cells. In Vitro Cell Dev Biol Anim 1999; 35:98-101. [PMID: 10475264 DOI: 10.1007/s11626-999-0008-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cell cycle synchronization of tumor cells by exposure to hyperbaric oxygenation (HBO) may increase the efficacy of chemotherapy or radiation by placing cells into a chemosensitive portion of the cycle. The purpose of the current study was to examine oxygen pressure-dependent relationships with respect to the cell cycle in prostate tumor cells in vitro. LNCaP cells were grown in an incubator at 21% O2 and then exposed to 100% oxygen at pressures up to 6 atmospheres (atm) for 1.5 h. Cells were then returned to the incubator and evaluated for DNA content by propidium iodide and new DNA synthesis with a pulse-chase experiment. Cell cycle effects were evaluated by flow cytometry. Exposure to HBO increased the percentage of cells synthesizing new DNA in a dose-dependent fashion: 0 atm, 44%; 6 atm, 65%. Cells that synthesize new DNA accumulate in G2/M as a function of partial pressure of oxygen. These results suggest that HBO induces cells to enter the cell cycle and accumulate in G2/M. Cell cycle synchronization and entry of senescent cells into the cell cycle suggest that HBO may be a useful adjuvant to chemotherapy or radiation in the treatment of prostate cancer. There are two potential mechanisms of action that may make HBO efficacious in the treatment of prostate cancer. HBO may potentiate cancer chemotherapeutic agents that cause damage to DNA during DNA synthesis or HBO may inhibit cell division causing accumulation in G2/M.
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Affiliation(s)
- J E Kalns
- Davis Hyperbaric Laboratory, Brooks Air Force Base, San Antonio, Texas 78235-5119, USA
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28
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Dimitrijevich SD, Paranjape S, Wilson JR, Gracy RW, Mills JG. Effect of hyperbaric oxygen on human skin cells in culture and in human dermal and skin equivalents. Wound Repair Regen 1999; 7:53-64. [PMID: 10231506 DOI: 10.1046/j.1524-475x.1999.00053.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A critical stage of cutaneous wound healing is the development and maturation of the epidermis. In the aged, and in certain pathologies, this repair process is compromised due to a variety of deficiencies, one of which is tissue oxygenation. Several phases of wound healing are dependent on adequate tissue oxygen levels, and hyperbaric oxygenation has been shown to transiently elevate these levels. The use of human cell monolayers, dermal equivalents and human skin equivalents provide excellent opportunities for studying wound healing using in vivo relevant models. The goal of this study was to examine the effect of hyperbaric oxygen on cell proliferation, differentiation, and matrix biosynthesis in monolayer cultures and epidermopoiesis in the developing skin equivalent. Normal human dermal fibroblasts, keratinocytes and melanocytes, dermal equivalents and skin equivalents were exposed to hyperbaric oxygen at pressures up to three atmospheres, for up to 10 consecutive daily treatments lasting 90 minutes each. Increase in fibroblast proliferation (cf., 30% at 1 atmosphere after 10 days treatment), was observed without a significant effect on proliferation of normal human melanocytes and glycosaminoglycan synthesis. Stimulation of collagen synthesis after two days of treatment was only significant at 1 atmosphere (about 20% increase) but this differential was not observed after 5 days of treatment. Hyperbaric oxygenation above 2 atmospheres, inhibited proliferation of fibroblasts and keratinocytes in cell monolayer cultures (e.g., a 10 day treatment at 3 atmospheres appeared cytostatic to keratinocytes). In contrast, hyperbaric treatment up to 3 atmospheres dramatically enhanced keratinocyte differentiation, and epidermopoiesis in the complete human skin equivalent. These results support the importance of hyperbaric oxygen therapy in wound healing, and should provide an insight into oxygen utilization during repair of peripheral human tissue. The results also show the utility of the human skin equivalent as a model for evaluation of parameters involved in wound healing.
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Affiliation(s)
- S D Dimitrijevich
- Department of Molecular Biology and Immunology, Wound Healing Research Institute, University of North Texas Health Science Center, Fort Worth,Texas 76107, USA
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29
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Allen CB, Guo XL, White CW. Changes in pulmonary expression of hexokinase and glucose transporter mRNAs in rats adapted to hyperoxia. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:L320-9. [PMID: 9530166 DOI: 10.1152/ajplung.1998.274.3.l320] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Impairment of lung aconitase activity, citric acid cycle, and mitochondrial respiration by hyperoxia necessitates the elevation of glycolysis for energy production and of pentose shunt activity for reducing equivalents. The molecular mechanisms that allow increased glucose utilization are unknown. Adult male and female rats were adapted to sublethal hyperoxia, equivalent to 83% oxygen at sea level, or air for 7 days. Lung RNA and protein increased in hyperoxia (197 and 57%, respectively), whereas total DNA was unchanged. In hyperoxia, lung total hexokinase (HK) activity increased threefold, and mRNAs for HK-II and -III were specifically upregulated. HK-I mRNA was unchanged. mRNAs for HK-II and -III gradually increased during the first 72 h in hyperoxia. HK-II mRNA was significantly elevated at 72 h, preceding changes in lung cell populations. Although virtually absent in air, HK-II activity was highly expressed in hyperoxia. Among lung glucose transporters, specific expression of mRNAs for GLUT-4 (insulin dependent) and sodium-glucose cotransporter-1 was decreased, whereas that for GLUT-1 was minimally changed. Adaptation to hyperoxia involves coordinated changes in gene expression for the proteins regulating pulmonary glucose transport.
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Affiliation(s)
- C B Allen
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado, USA
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30
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Allen CB, White CW. Glucose modulates cell death due to normobaric hyperoxia by maintaining cellular ATP. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:L159-64. [PMID: 9458814 DOI: 10.1152/ajplung.1998.274.1.l159] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To determine whether glucose depletion is a principal determinant of hyperoxic cell death in vitro, human lung epithelial-like cells (A549) were exposed to hyperoxia (95% O2) in either 10, 30, or 50 ml of medium (Ham's F-12K). Glucose was depleted in the medium after 36, 60, or 96 h, respectively. Medium lactate dehydrogenase (LDH) activity increased only after glucose was depleted. To confirm that glucose depletion was critical to cell death, cells exposed to 95% O2 were supplemented with glucose at regular intervals to reestablish initial medium glucose concentrations. Other cells received no supplements. Without supplementation, glucose was depleted within 48 h, followed within 12 h by an almost complete loss of cell ATP and elevated medium LDH activity. Glucose-supplemented cells appeared normal microscopically and did not release LDH activity despite an extracellular pH of 6.5 due to fermentation. Additional experiments at sea-level pressure confirmed that glucose supplementation prevents extensive cell death in hyperoxia in cultured A549 cells.
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Affiliation(s)
- C B Allen
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado, USA
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31
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Hussain N, Wu F, Christian C, Kresch MJ. Hyperoxia inhibits fetal rat lung fibroblast proliferation and expression of procollagens. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:L726-32. [PMID: 9357846 DOI: 10.1152/ajplung.1997.273.4.l726] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The direct effects of hyperoxia on collagen production by fetal lung fibroblasts are unknown and would be important to the understanding of the molecular mechanisms involved in bronchopulmonary dysplasia in premature infants. We studied the effect of hyperoxia on 1) proliferation, 2) mRNA levels for type I and III procollagens, and 3) net collagen production in primary cultures of fetal rat lung fibroblasts. Fibroblasts from 19-day-old rat fetuses (term is 22 days) were obtained. Test plates were incubated in hyperoxia and controls in room air for varying time periods. Cell viability in both conditions was >97% as determined by trypan blue exclusion. Fibroblast proliferation in nonconfluent cultures was found to be significantly reduced with exposure to hyperoxia (P < 0.001). Steady-state levels of type I and III procollagen mRNAs, analyzed on Northern blots hybridized to [32P]cDNA probes, were significantly decreased in hyperoxia (P < 0.01). This effect was noted as early as 4 h of exposure to hyperoxia and persisted for 5 days. There was a significant inverse correlation between duration of exposure to O2 and steady-state levels of mRNA for alpha1(I)-procollagen (r = -0.904) and alpha1(III)-procollagen (r = -0.971). There were no significant changes in steady-state levels of beta-actin mRNA. We also found a significant decrease in collagen synthesis in hyperoxia-exposed fibroblasts (P < 0.05). We conclude that hyperoxia directly effects a reduction in fetal lung fibroblast proliferation and net collagen production at a pretranslational level.
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Affiliation(s)
- N Hussain
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington 06030-2203, USA
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32
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Abstract
Recent studies indicate that smooth muscle cell (SMC) growth and morphology can be modulated by repetitive strain. However, there is very little known about the influence of pressure, without an associated cell stretch, on SMC phenotype. To study this, cultured bovine aortic SMC were grown on a rigid surface and placed in a custom-designed plexiglass pressure chamber with a carefully regulated 5% CO2/air environment. SMC were exposed to either atmospheric, 105 mm Hg or 120/90 mm Hg pressure at a frequency of 60 cycles/min (0.5 s systole, 0.5 s diastole). SMC number was determined on days 1, 3, 5, 7 and 9. SMC exposed to pressure were more elongated and displayed a significant increase in cell number by day 5 which persisted until day 9. Lactate dehydrogenase (LDH) in the conditioned media, an index of cytotoxicity, was not different between the groups at each time point. There was also no difference in pH or pCO2 of the media of SMC in any group. This is the first report of the effects of increased static and pulsatile pressure on SMC in vitro and indicates an increased proliferative rate. We hypothesize that the systemic pressure that the blood vessel is exposed to in vivo may have a significant regulatory influence on the phenotype of the smooth muscle cells which may affect the SMC response to injury or stimuli.
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Affiliation(s)
- M Watase
- Department of Surgery (Vascular), Yale University School of Medicine, New Haven, CT 06510, USA
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33
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Fridovich I. Superoxide anion radical (O2-.), superoxide dismutases, and related matters. J Biol Chem 1997; 272:18515-7. [PMID: 9228011 DOI: 10.1074/jbc.272.30.18515] [Citation(s) in RCA: 837] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- I Fridovich
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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34
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Macfarlane CM. In vitro influence of sublethal hypoxia on differentiation of the 3T3-L1 preadipose cell line and its physiological implications. Life Sci 1997; 60:1923-31. [PMID: 9155003 DOI: 10.1016/s0024-3205(97)00154-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Exposure of cultures of 3T3-L1 preadipose cells to nitrogen for 16 hours kills almost all of the cells, but after exposure to 5% oxygen for 16 hours most of the cells survive, and recover when culture is continued in 20% oxygen. The extent of recovery depends on the insulin concentration of the medium. Isotope incorporation and flow cytometry experiments show that exposure to 5% oxygen for 16 hours growth arrests the cells and leads to an elongation of the G1-phase of the cell cycle. When 3T3-L1 cells are growth arrested in the presence of 5% oxygen and allowed to recover in the presence of 5 microg/ml insulin under 20% oxygen, they can be induced to differentiate by treatment with carbacyclin during the period of growth arrest. Activity of the marker enzyme glycerol-3-phosphate dehydrogenase increases from 46.5+/-17 mU/mg protein to 1506+/-271 mU/mg protein. The extent of differentiation is exponentially related to the concentration of carbacyclin in the medium.
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Affiliation(s)
- C M Macfarlane
- Department of Chemical Pathology, Medical Faculty, University of Stellenbosch, Tygerberg Hospital, South Africa.
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35
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Yoshida H, Mizutani S, Ikenaga H. Scale-up of interleukin-6 production by BHK cells using a radial-flow reactor packed with porous glass beads. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0922-338x(97)82071-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Cristofalo VJ, Pignolo RJ. Cell Culture as a Model. Compr Physiol 1995. [DOI: 10.1002/cphy.cp110104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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37
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Chen Q, Fischer A, Reagan JD, Yan LJ, Ames BN. Oxidative DNA damage and senescence of human diploid fibroblast cells. Proc Natl Acad Sci U S A 1995; 92:4337-41. [PMID: 7753808 PMCID: PMC41939 DOI: 10.1073/pnas.92.10.4337] [Citation(s) in RCA: 492] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human diploid fibroblast cells cease growth in culture after a finite number of population doublings. To address the cause of growth cessation in senescent IMR-90 human fibroblast cells, we determined the level of oxidative DNA damage by using 8-oxoguanine excised from DNA and 8-oxo-2'-deoxyguanosine in DNA as markers. Senescent cells excise from DNA four times more 8-oxoguanine per day than do early-passage young cells. The steady-state level of 8-oxo-2'-deoxyguanosine in DNA is approximately 35% higher in senescent cells than in young cells. Measurement of protein carbonyls shows that senescent cells did not appear to have elevated protein oxidation. To reduce the level of oxidative damage, we cultured cells under a more physiological O2 concentration (3%) and compared the replicative life span to the cells cultured at the O2 concentration of air (20%). We found that cells grown under 3% O2 achieved 50% more population doublings during their lifetime. Such an extension of life span resulted from the delayed onset of senescence and elevation of growth rate and saturation density of cells at all passages. The spin-trapping agent alpha-phenyl-t-butyl nitrone (PBN), which can act as an antioxidant, also effectively delayed senescence and rejuvenated near senescent cells. The effect is dose-dependent and is most pronounced for cells at the stage just before entry into senescence. Our data support the hypothesis that oxidative DNA damage contributes to replicative cessation in human diploid fibroblast cells.
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Affiliation(s)
- Q Chen
- Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720, USA
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38
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Eyer K, Oeggerli A, Heinzle E. On-line gas analysis in animal cell cultivation: II. Methods for oxygen uptake rate estimation and its application to controlled feeding of glutamine. Biotechnol Bioeng 1995; 45:54-62. [DOI: 10.1002/bit.260450108] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Yuan H, Kaneko T, Kaji K, Kondo H, Matsuo M. Species difference in the resistibility of embryonic fibroblasts against oxygen-induced growth inhibition. Comp Biochem Physiol B Biochem Mol Biol 1995; 110:145-54. [PMID: 7858938 DOI: 10.1016/0305-0491(94)00137-j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The growth of fibroblasts, which were isolated from human, rabbit, rat, mouse, and chick embryos, was inhibited partially under 50% oxygen and nearly completely under 95% oxygen. There was species difference in the resistivity of these cells against oxygen-induced growth inhibition. The extent of the resistivity was in the following order: chick cells > rat cells > human cells > rabbit cells approximately mouse cells. The order of their ability to recover from oxygen-induced growth inhibition was similar to the above order of species. There was also species difference in their antioxidant enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase activities, and their reduced glutathione concentration. Chick cells, having the highest resistivity against oxygen-induced growth inhibition, were at the lowest activity levels of antioxidant enzymes and at the highest concentration level of reduced glutathione. The species difference in resistivity against oxygen-induced growth inhibition seems to depend on the reduced glutathione concentration, but not on the antioxidant enzyme activities.
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Affiliation(s)
- H Yuan
- Tokyo Metropolitan Institute of Gerontology, Japan
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40
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Ogburn CE, Turker MS, Kavanagh TJ, Disteche CM, Smith AC, Fukuchi K, Martin GM. Oxygen-resistant multipotent embryonic carcinoma cell lines exhibit antimutator phenotypes. SOMATIC CELL AND MOLECULAR GENETICS 1994; 20:361-70. [PMID: 7825058 DOI: 10.1007/bf02257453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Stable, oxygen-resistant cell lines (O2R) were isolated from P19 and P19H22 (APRT hemizygote) mouse embryonic carcinoma cells by serial exposures of increasing durations to 95% O2. Neurally differentiated progeny were also oxygen-resistant. P19O2R exhibited reduced oxygen-mediated micronucleation and a 10- to 20-fold reduction of the forward mutation rate at the HPRT locus in 20% O2. P19H22O2R cells showed reduced frequencies of colonies resistant to 2,6-diaminopurine. The modal karyotype of P19O2R was identical to that of a nonmodal karyotype present in the parental line [39,X,-Y, add(14)]. There was no evidence of enhanced resistance to ionizing radiation. We conclude that this general approach, when applied to pluripotent embryonic stem cells, has the potential to lead to the synthesis of antimutator strains of mice.
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Affiliation(s)
- C E Ogburn
- Department of Pathology, University of Washington, Seattle 98195
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41
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Takagi M, Ueda K. Comparison of the optimal culture conditions for cell growth and tissue plasminogen activator production by human embryo lung cells on microcarriers. Appl Microbiol Biotechnol 1994; 41:565-70. [PMID: 7765084 DOI: 10.1007/bf00178490] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Optimization of culture conditions such as the dissolved O2 (DO) concentration, temperature and pH was attempted regarding both cell growth and the production of tissue plasminogen activator (TPA) in a microcarrier cell culture of human embryo lung cells. The growth rate was suppressed at a DO concentration below 30% saturation. From the pH range 7.2-7.6, both the specific growth rate and maximal cell concentration decreased. At a lower temperature than 37 degrees C, although both the specific growth rate and the maximal cell concentration decreased, the cell concentration was maintained for a longer time during the production period, high TPA productivity being maintained. As the optimal conditions for culture growth, a DO concentration of 30% saturation or over, temperature of 37 degrees C and pH of 7.4 are recommended. However, for TPA production after cell culture growth, the DO concentration should be in the range 20-30% O2 saturation, and the temperature and pH should be lowered to 33 degrees C and 6.8, respectively.
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Affiliation(s)
- M Takagi
- Life Science Research Laboratories, Asahi Chemical Industry Company Ltd., Shizuoka, Japan
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42
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Abstract
The effect of hyperbaric oxygen on the proliferative and synthetic responses of fibroblasts derived from wounds and normal skin was examined in this study. Hyperbaric oxygen treatment resulted in a slight decrease in fibroblast proliferation but an increase in the synthesis of extracellular matrix components. Relating these results to the process of wound healing suggests that hyperbaric oxygen therapy would increase the matrix:cell ratio, which could have important consequences for repair processes such as cell migration and regulation of cell activity. There was no apparent difference in the response to hyperbaric oxygen of fibroblasts derived from different sources.
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Affiliation(s)
| | | | - K G Harding
- Director, Wound Healing Research Unit, Department of Surgery, University of Wales College of Medicine, Cardiff
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43
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Wrede D, Salisch H, Siegmann O. Oxygen concentration and asexual development of Eimeria tenella in cell cultures. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE B. JOURNAL OF VETERINARY MEDICINE. SERIES B 1993; 40:391-6. [PMID: 8284951 DOI: 10.1111/j.1439-0450.1993.tb00155.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Primary chicken kidney cells in Flexiperm cultures were either inoculated with Eimeria tenella sporozoites or incubated as noninoculated controls. Oxygen concentration was reduced (10 or 15 vol% O2, 5 vol% CO2) or increased (25 or 30 vol% O2, 5 vol% CO2) in a triple gas incubator (Heraeus B 5061 EK/O2) and retained in a CO2-air incubator (20 vol% O2, 5 vol% CO2) 24 hours post inoculation (hpi). Mature second generation schizonts (mS2) were counted microscopically at 120 hpi and numbers were compared either as mS2 or mS2/cm2 confluent cells. Asexual development of Eimeria tenella was neither stimulated nor inhibited by different oxygen concentrations, indicating that higher numbers of schizonts in cultures under reducing conditions reported earlier are probably a result of increased invasion rates of sporozoites.
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Affiliation(s)
- D Wrede
- Clinic for Poultry, Hannover School of Veterinary Medicine, Germany
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44
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Misakian M, Sheppard AR, Krause D, Frazier ME, Miller DL. Biological, physical, and electrical parameters for in vitro studies with ELF magnetic and electric fields: a primer. Bioelectromagnetics 1993; Suppl 2:1-73. [PMID: 8357346 DOI: 10.1002/bem.2250140703] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This paper presents material which is intended to assist researchers in identifying and controlling a range of biological, electrical, and other physical parameters that can affect the outcome of in vitro studies with extremely low frequency (ELF) magnetic and electric fields. Brief descriptions of power line magnetic and electric fields are provided and methods for the generation of 60 Hz as well as other ELF fields in the laboratory are surveyed. Methods for calculating and measuring exposure parameters in culture medium are also described. Relating in vitro and internal in vivo exposure conditions across different animal species is discussed to aid researchers in selecting levels of field exposure. The text is purposely elementary, and sometimes brief, with references provided to aid the interested reader in obtaining a fuller understanding of the many topics. Because the range of experimental parameters that can influence the outcome of in vitro studies with ELF fields is so broad, a multidisciplinary approach is normally required to carry out the research.
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Affiliation(s)
- M Misakian
- National Institute of Standards and Technology, Electricity Division, Gaithersburg, Maryland 20899
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45
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Boulton M, Patel B, Khaliq A, Moriarty P, Jarvis-Evans J, McLeod D. Modulators and milieu in preretinal neovascularisation. Eye (Lond) 1992; 6 ( Pt 6):560-5. [PMID: 1289131 DOI: 10.1038/eye.1992.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- M Boulton
- Department of Ophthalmology, University of Manchester, UK
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46
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Mahajan S, Garg SK. Life prolonging effect of butylated hydroxy anisole in Callosobruchus maculatus F. (Coleoptera: Bruchidae). Arch Gerontol Geriatr 1992; 15:71-8. [PMID: 15374382 DOI: 10.1016/0167-4943(92)90041-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/1991] [Revised: 04/06/1992] [Accepted: 04/07/1992] [Indexed: 12/01/2022]
Abstract
The present study deals with the effect of butylated hydroxy anisole (BHA), an antioxidant, on longevity and fecundity of insects infesting BHA soaked seeds of Vigna radiata. Median (LT(50)) and maximum (LT(100)) life spans as well as post-reproductive period of the insect reared on optimal concentration (1 mM) of antioxidant soaked seeds were higher than the control. However, the reproductive period of the females and the number of eggs laid/female declined. The results are indicative of the increased life span of the insects on BHA feeding at the cost of the reproductive period.
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Affiliation(s)
- S Mahajan
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar 143005, India
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47
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Parulekar SJ, Hassell T, Tripathi SC. Recent developments in vertebrate cell culture technology. INTERNATIONAL REVIEW OF CYTOLOGY 1992; 142:145-211. [PMID: 1487395 DOI: 10.1016/s0074-7696(08)62076-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- S J Parulekar
- Department of Chemical Engineering, Illinois Institute of Technology, Chicago 60616
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48
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Rosen P, Boulton M, Moriarty P, Khaliq A, McLeod D. Effect of varying oxygen concentrations on the proliferation of retinal microvascular cells in vitro. Exp Eye Res 1991; 53:597-601. [PMID: 1743258 DOI: 10.1016/0014-4835(91)90218-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Microvascular fragments and pure cultures of either retinal microvascular endothelial cells, retinal pericytes or Tenon's capsule fibroblasts were grown on a gas permeable substrate while exposed to varying oxygen concentrations (5, 10, 20, 40 and 95% oxygen). For all three cell types cell proliferation was greatest under the lowest oxygen concentration and decreased as the oxygen concentration increased. The decrease in the proliferative ability of cells exposed to the higher oxygen concentrations could be reversed if the cells were returned to a normoxic environment. Endothelial cells were the most sensitive to changes in oxygen tensions showing a proliferative response after 24 hr exposure as opposed to 48 hr for pericytes and fibroblasts. These results suggest a direct mechanism by which the intra-vitreal and intra-retinal oxygen tension may influence both the development of preretinal new vessels (in response to retinal ischaemia) and also the regression of neovascularization following scatter photocoagulation or vitrectomy.
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Affiliation(s)
- P Rosen
- Moorfields Eye Hospital, London, U.K
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49
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Horikoshi T, Balin AK, Carter DM. Effects of oxygen tension on the growth and pigmentation of normal human melanocytes. J Invest Dermatol 1991; 96:841-4. [PMID: 1904467 DOI: 10.1111/1523-1747.ep12474550] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of oxygen tension on human melanocyte growth, tyrosinase activity, and melanin production were assessed. Melanocytes, seeded at 10(4) cells/cm2, were grown in modified Eagle's medium (MEM) with 5% fetal bovine serum (FBS) and 10 ng/ml 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Flasks were equilibrated with gas mixtures containing 5% CO2 and various partial pressures of oxygen (PO2 7-620 mm Hg) and kept in incubators, which were electronically maintained at the desired oxygen tensions. Melanocytes grew best at PO2 from 6-34 mm Hg. Growth was reduced by 30% at PO2 142 mm Hg, and even more at O2 tensions greater than 230 mm Hg. A PO2 of 603 mm Hg was cytotoxic. Tyrosinase activity (assayed by the method of Pomerantz) was 300 microU/mg protein at PO2 7-34 mm Hg. At PO2 235 and 355 mm Hg tyrosinase activity decreased to about 100 microU/mg protein. The apparent Km for tyrosine was unchanged in melanocytes cultured at all experimental oxygen tensions. The Vmax, however, was decreased at the higher oxygen tensions (PO2 235 mm Hg). At PO2 6-135 mm Hg the melanin content was proportional to tyrosinase activity. At cytostatic oxygen tensions (PO2 235 and 355 mm Hg) the intracellular melanin content increased somewhat, although tyrosinase activity was decreased. Low oxygen tension is favorable for both melanocyte proliferation and tyrosinase activity.
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Affiliation(s)
- T Horikoshi
- Laboratory for Investigative Dermatology, Rockefeller University, New York, NY 10021-6399
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50
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Abstract
A mathematical model of cellular metabolism is used to relate the rates of cell division and waste production to the concentrations of oxygen and glucose in the medium in which a normal diploid cell culture is grown. The metabolic model in tandem with an earlier waste-content model based on the waste-product theory of aging provides a unified cell-culture model with which population size and intracellular waste content can be calculated. Population size is measured by the number of population doublings which have been achieved. After suitable adjustment of parameters in the metabolic model, maximum values of population size are calculated numerically with the use of the unified model. Results show that the population maxima are related in a plausible way to the oxygen and glucose concentrations. The effects of temperature changes and contact inhibition of growth are also simulated. Small changes in the cell-division and waste-production rates can cause transformation to unlimited growth in the waste-content model, but the unified model is not correspondingly sensitive to changes in the oxygen and glucose concentrations or to changes in temperature.
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Affiliation(s)
- H R Hirsch
- Department of Physiology and Biophysics, College of Medicine, University of Kentucky, Lexington 40536-0084
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