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Oliver AA, Senol YC, Bilgin C, Schaffer JE, Kadirvel R, Kallmes DF, Wainwright JM. Intraluminal Flow Diverter Design Primer for Neurointerventionalists. AJNR Am J Neuroradiol 2024; 45:365-370. [PMID: 38164542 DOI: 10.3174/ajnr.a8076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/29/2023] [Indexed: 01/03/2024]
Abstract
The clinical use of flow diverters for the treatment of intracranial aneurysms has rapidly grown. Consequently, the market and technology for these devices has also grown. Clinical performance characteristics of the flow diverter are well-known to the clinician. However, the engineering design principles behind how these devices achieve ideal clinical performance are less understood. This primer will summarize flow diverter design parameters for neurointerventionalists with the aim of promoting collaboration between clinicians and engineers.
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Affiliation(s)
- Alexander A Oliver
- From the Department of Biomedical Engineering and Physiology (A.A.O., D.F.K.), Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota
- Department of Radiology (A.A.O., C.B., R.K., D.F.K.), Mayo Clinic, Rochester, Minnesota
| | - Yigit Can Senol
- Department of Neurologic Surgery (Y.C.S., R.K.), Mayo Clinic, Rochester, Minnesota
| | - Cem Bilgin
- Department of Radiology (A.A.O., C.B., R.K., D.F.K.), Mayo Clinic, Rochester, Minnesota
| | | | - Ramanathan Kadirvel
- Department of Radiology (A.A.O., C.B., R.K., D.F.K.), Mayo Clinic, Rochester, Minnesota
- Department of Neurologic Surgery (Y.C.S., R.K.), Mayo Clinic, Rochester, Minnesota
| | - David F Kallmes
- From the Department of Biomedical Engineering and Physiology (A.A.O., D.F.K.), Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota
- Department of Radiology (A.A.O., C.B., R.K., D.F.K.), Mayo Clinic, Rochester, Minnesota
| | - John M Wainwright
- MIVI Neuroscience (J.M.W.), Eden Prairie, Minnesota
- The Henry Samueli School of Engineering (J.M.W.), University of California, Irvine, California
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Oliver AA, Bilgin C, Vercnocke AJ, Carlson KD, Kadirvel R, Guillory RJ, Griebel AJ, Schaffer JE, Dragomir-Daescu D, Kallmes DF. Benchtop proof of concept and comparison of iron- and magnesium-based bioresorbable flow diverters. J Neurosurg 2023; 139:150-156. [PMID: 36681964 PMCID: PMC10824252 DOI: 10.3171/2022.11.jns222213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/04/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Bioresorbable flow diverters (BRFDs) could significantly improve the performance of next-generation flow diverter technology. In the current work, magnesium and iron alloy BRFDs were prototyped and compared in terms of porosity/pore density, radial strength, flow diversion functionality, and resorption kinetics to offer insights into selecting the best available bioresorbable metal candidate for the BRFD application. METHODS BRFDs were constructed with braided wires made from alloys of magnesium (MgBRFD) or iron (FeBRFD). Pore density and crush resistance force were measured using established methods. BRFDs were deployed in silicone aneurysm models attached to flow loops to investigate flow diversion functionality and resorption kinetics in a simulated physiological environment. RESULTS The FeBRFD exhibited higher pore density (9.9 vs 4.3 pores/mm2) and crush resistance force (0.69 ± 0.05 vs 0.53 ± 0.05 N/cm, p = 0.0765, n = 3 per group) than the MgBRFD, although both crush resistances were within the range previously reported for FDA-approved flow diverters. The FeBRFD demonstrated greater flow diversion functionality than the MgBRFD, with significantly higher values of established flow diversion metrics (mean transit time 159.6 ± 11.9 vs 110.9 ± 1.6, p = 0.015; inverse washout slope 192.5 ± 9.0 vs 116.5 ± 1.5, p = 0.001; n = 3 per group; both metrics expressed as a percentage of the control condition). Last, the FeBRFD was able to maintain its braided structure for > 12 weeks, whereas the MgBRFD was almost completely resorbed after 5 weeks. CONCLUSIONS The results of this study demonstrated the ability to manufacture BRFDs with magnesium and iron alloys. The data suggest that the iron alloy is the superior material candidate for the BRFD application due to its higher mechanical strength and lower resorption rate relative to the magnesium alloy.
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Affiliation(s)
- Alexander A. Oliver
- Biomedical Engineering and Physiology, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota, USA
- Radiology, Mayo Clinic, Rochester, Minnesota, USA
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Cem Bilgin
- Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Kent D. Carlson
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Ramanathan Kadirvel
- Radiology, Mayo Clinic, Rochester, Minnesota, USA
- Neurosurgery, Rochester, Minnesota, USA
| | - Roger J Guillory
- Biomedical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | | | | | - Dan Dragomir-Daescu
- Biomedical Engineering and Physiology, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota, USA
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - David F. Kallmes
- Biomedical Engineering and Physiology, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, Minnesota, USA
- Radiology, Mayo Clinic, Rochester, Minnesota, USA
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ter Meer M, Dillion R, Nielsen SM, Walther R, Meyer RL, Daamen WF, van den Heuvel LP, van der Vliet JA, Lomme RMLM, Hoogeveen YL, Schultze Kool LJ, Schaffer JE, Zelikin AN. Innate glycosidic activity in metallic implants for localized synthesis of antibacterial drugs. Chem Commun (Camb) 2019; 55:443-446. [DOI: 10.1039/c8cc08737g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The unexpected discovery presented herein is that industrialized metallic wires can perform conversion of the glucuronide prodrugs with ensuing antibacterial effects.
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Affiliation(s)
- Marja ter Meer
- Department of Radiology and Nuclear Medicine
- Radboud university medical center
- Nijmegen
- The Netherlands
| | - Ross Dillion
- Fort Wayne Metals Research Products Corp
- Research and Development
- Fort Wayne
- USA
| | | | - Raoul Walther
- Department of Chemistry
- Aarhus University
- Aarhus
- Denmark
| | - Rikke L. Meyer
- iNano Interdisciplinary Nanoscience Centre
- Aarhus University
- Aarhus
- Denmark
| | - Willeke F. Daamen
- Department of Biochemistry
- Radboud Institute for Molecular Life Sciences
- Radboud university medical center
- Nijmegen
- The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Pediatrics/Pediatric Nephrology
- Radboud university medical center
- Nijmegen
- The Netherlands
- Department of Development and Regeneration/Pediatrics
| | | | | | - Yvonne L. Hoogeveen
- Department of Radiology and Nuclear Medicine
- Radboud university medical center
- Nijmegen
- The Netherlands
| | - Leo J. Schultze Kool
- Department of Radiology and Nuclear Medicine
- Radboud university medical center
- Nijmegen
- The Netherlands
| | - Jeremy E. Schaffer
- Fort Wayne Metals Research Products Corp
- Research and Development
- Fort Wayne
- USA
| | - Alexander N. Zelikin
- iNano Interdisciplinary Nanoscience Centre
- Aarhus University
- Aarhus
- Denmark
- Department of Chemistry
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Abstract
Environmental and socioeconomic changes over the past thirty years have contributed to a dramatic rise in the worldwide prevalence of obesity. Heart disease is amongst the most serious health risks of obesity, with increases in both atherosclerotic coronary heart disease and heart failure among obese individuals. In this review, we focus on primary myocardial alterations in obesity that include hypertrophic remodelling and diastolic dysfunction. Obesity-associated perturbations in myocardial and systemic lipid metabolism are important contributors to cardiovascular complications of obesity. Accumulation of excess lipid in nonadipose cells of the cardiovascular system can cause cell dysfunction and cell death, a process known as lipotoxicity. Lipotoxicity has been modelled in mice using high-fat diet feeding, inbred lines with mutations in leptin receptor signalling, and in genetically engineered mice with enhanced myocardial fatty acid uptake, altered lipid droplet homoeostasis or decreased cardiac fatty acid oxidation. These studies, along with findings in cell culture model systems, indicate that the molecular pathophysiology of lipid overload involves endoplasmic reticulum stress, alterations in autophagy, de novo ceramide synthesis, oxidative stress, inflammation and changes in gene expression. We highlight recent advances that extend our understanding of the impact of obesity and altered lipid metabolism on cardiac function.
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Affiliation(s)
- A C Sletten
- Department of Medicine, Washington University, St Louis, MO, USA
| | - L R Peterson
- Department of Medicine, Washington University, St Louis, MO, USA
| | - J E Schaffer
- Department of Medicine, Washington University, St Louis, MO, USA
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Winther AK, Fejerskov B, ter Meer M, Jensen NB, Dillion R, Schaffer JE, Chandrawati R, Stevens MM, Schultze Kool LJ, Simonsen U, Zelikin AN. Enzyme Prodrug Therapy Achieves Site-Specific, Personalized Physiological Responses to the Locally Produced Nitric Oxide. ACS Appl Mater Interfaces 2018; 10:10741-10751. [PMID: 29570264 PMCID: PMC5887086 DOI: 10.1021/acsami.8b01658] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/15/2018] [Indexed: 05/23/2023]
Abstract
Nitric oxide (NO) is a highly potent but short-lived endogenous radical with a wide spectrum of physiological activities. In this work, we developed an enzymatic approach to the site-specific synthesis of NO mediated by biocatalytic surface coatings. Multilayered polyelectrolyte films were optimized as host compartments for the immobilized β-galactosidase (β-Gal) enzyme through a screen of eight polycations and eight polyanions. The lead composition was used to achieve localized production of NO through the addition of β-Gal-NONOate, a prodrug that releases NO following enzymatic bioconversion. The resulting coatings afforded physiologically relevant flux of NO matching that of the healthy human endothelium. The antiproliferative effect due to the synthesized NO in cell culture was site-specific: within a multiwell dish with freely shared media and nutrients, a 10-fold inhibition of cell growth was achieved on top of the biocatalytic coatings compared to the immediately adjacent enzyme-free microwells. The physiological effect of NO produced via the enzyme prodrug therapy was validated ex vivo in isolated arteries through the measurement of vasodilation. Biocatalytic coatings were deposited on wires produced using alloys used in clinical practice and successfully mediated a NONOate concentration-dependent vasodilation in the small arteries of rats. The results of this study present an exciting opportunity to manufacture implantable biomaterials with physiological responses controlled to the desired level for personalized treatment.
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Affiliation(s)
- Anna K. Winther
- Department
of Chemistry, Department of Biomedicine, and iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus 8000, Denmark
| | - Betina Fejerskov
- Department
of Chemistry, Department of Biomedicine, and iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus 8000, Denmark
| | - Marja ter Meer
- Department of Radiology and Nuclear Medicine 766, Radboud University Medical Center, Nijmegen 6525, The Netherlands
| | - Najah B.S. Jensen
- Department
of Chemistry, Department of Biomedicine, and iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus 8000, Denmark
| | - Ross Dillion
- Fort Wayne Metals, Research and Development, Fort Wayne 46809, Indiana, United States
| | - Jeremy E. Schaffer
- Fort Wayne Metals, Research and Development, Fort Wayne 46809, Indiana, United States
| | - Rona Chandrawati
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Leo J. Schultze Kool
- Department of Radiology and Nuclear Medicine 766, Radboud University Medical Center, Nijmegen 6525, The Netherlands
| | - Ulf Simonsen
- Department
of Chemistry, Department of Biomedicine, and iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus 8000, Denmark
| | - Alexander N. Zelikin
- Department
of Chemistry, Department of Biomedicine, and iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus 8000, Denmark
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Griebel AJ, Schaffer JE, Hopkins TM, Alghalayini A, Mkorombindo T, Ojo KO, Xu Z, Little KJ, Pixley SK. An in vitro and in vivo characterization of fine WE43B magnesium wire with varied thermomechanical processing conditions. J Biomed Mater Res B Appl Biomater 2017; 106:1987-1997. [PMID: 28990317 DOI: 10.1002/jbm.b.34008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 11/09/2022]
Abstract
Absorbable implants made of magnesium alloys may revolutionize surgical intervention, and fine magnesium wire will be critical to many applications. Functionally, the wires must have sufficient mechanical properties to withstand implantation and in-service loading, have excellent tissue tolerance, and exhibit an appropriate degradation rate for the application. Alloy chemistry and thermomechanical processing conditions will significantly impact the material's functional performance, but the exact translation of these parameters to implant performance is unclear. With this in mind, fine (127 µm) WE43B magnesium alloy wires in five thermomechanical process (TMP) conditions (90% cold work [CW], and 250, 375, 400, and 450°C heat treatments) were investigated for their effect on mechanical and corrosion behavior. The TMP conditions gave clear metallurgical differences: transverse grain dimensions ranged from 200 nm (CW) to 3 µm (450°C), UTS varied from 324 MPa (450°C) to 608 MPa (250°C), and surgical knotting showed some were suitable (CW, 400°C, 450°C) while others were not (250°C, 350°C). In vitro and in vivo corrosion testing yielded interesting and in some cases conflicting results. After 1 month immersion in cell culture medium, wire corrosion was extensive, and TMP conditions altered the macrocorrosion morphology but not the rate or total release of magnesium ions. After 1 month subdermal implantation in mice, all wires were well tolerated and showed very little corrosion (per µCT and histology), but differences in localized corrosion were detected between conditions. This study indicates that WE43B wires treated at 450°C may be most suitable for surgical knotting procedures. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1987-1997, 2018.
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Affiliation(s)
- Adam J Griebel
- Research & Development, Fort Wayne Metals Research Products Corp, Fort Wayne, Indiana
| | - Jeremy E Schaffer
- Research & Development, Fort Wayne Metals Research Products Corp, Fort Wayne, Indiana
| | - Tracy M Hopkins
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Alaa Alghalayini
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Tinomudaishe Mkorombindo
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Kolade O Ojo
- Department of Chemistry, University of Cincinnati College of Arts & Sciences, Cincinnati, Ohio
| | - Zhigang Xu
- Department of Mechanical Engineering, North Carolina A&T State University, Greensboro, North Carolina
| | - Kevin J Little
- Department of Orthopaedic Surgery, Division of Pediatric Orthopaedics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Sarah K Pixley
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
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7
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Ter Meer M, Daamen WF, Hoogeveen YL, van Son GJF, Schaffer JE, van der Vliet JA, Kool LJS, van den Heuvel LP. Continuously Grooved Stent Struts for Enhanced Endothelial Cell Seeding. Cardiovasc Intervent Radiol 2017; 40:1237-1245. [PMID: 28470391 PMCID: PMC5489614 DOI: 10.1007/s00270-017-1659-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 04/21/2017] [Indexed: 02/04/2023]
Abstract
Purpose Implantation of pre-endothelialized stents could enhance cellular recovery of a damaged vessel wall provided attached cells remain viable, functional and are present in sufficient numbers after deployment. The purpose of this study was to evaluate the feasibility of grooved stainless steel (SS) stents as a primary endothelial cell (EC) carrier with potentially enhanced EC protection upon stent deployment. Materials and Methods Attachment and behavior of enzymatically harvested human adult venous ECs seeded onto gelatin-coated vascular stents were evaluated in an in vitro setting. Smooth and grooved SS stents and smooth nitinol stents were studied. Results All cells expressed EC markers vWF and CD31. Using rotational seeding for a period of 16–24 h, ECs attached firmly to the stents with sufficient coverage to form a confluent EC monolayer. The grooved SS wire design was found to enable attachment of three times the number of cells compared to smooth wires. This also resulted in an increased number of cells remaining on the stent after deployment and after pulsatile flow of 180 ml/min for 24 h, which did not result in additional EC detachment. Conclusions The grooved stent provides a potential percutaneous means to deliver sufficient numbers of viable and functional cells to a vessel segment during vascular intervention. The grooves were found to offer a favorable surface for EC attachment and protection during stent deployment in an in vitro setting. Electronic supplementary material The online version of this article (doi:10.1007/s00270-017-1659-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marja Ter Meer
- Department of Radiology and Nuclear Medicine (766), Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Willeke F Daamen
- Department of Biochemistry 280, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Yvonne L Hoogeveen
- Department of Radiology and Nuclear Medicine (766), Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Gijs J F van Son
- Department of Radiology and Nuclear Medicine (766), Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Jeremy E Schaffer
- Fort Wayne Metals, Research and Development, 9609 Ardmore Avenue, Fort Wayne, IN, 46809, USA
| | - J Adam van der Vliet
- Department of Surgery 618, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Leo J Schultze Kool
- Department of Radiology and Nuclear Medicine (766), Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Lambertus P van den Heuvel
- Department of Pediatrics/Pediatric Nephrology 774, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.,Department of Development and Regeneration/Pediatrics, Catholic University Leuven, PO Box 7003, 3000, Leuven, Belgium
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Caputa G, Zhao S, Criado AEG, Ory DS, Duncan JG, Schaffer JE. RNASET2 is required for ROS propagation during oxidative stress-mediated cell death. Cell Death Differ 2015. [PMID: 26206090 DOI: 10.1038/cdd.2015.105] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
RNASET2 is a ubiquitously expressed acidic ribonuclease that has been implicated in diverse pathophysiological processes including tumorigeneis, vitiligo, asthenozoospermia, and neurodegeneration. Prior studies indicate that RNASET2 is induced in response to oxidative stress and that overexpression of RNASET2 sensitizes cells to reactive oxygen species (ROS)-induced cell death through a mechanism that is independent of catalytic activity. Herein, we report a loss-of-function genetic screen that identified RNASET2 as an essential gene for lipotoxic cell death. Haploinsufficiency of RNASET2 confers increased antioxidant capacity and generalized resistance to oxidative stress-mediated cell death in cultured cells. This function is critically dependent on catalytic activity. Furthermore, knockdown of RNASET2 in the Drosophila fat body confers increased survival in the setting of oxidative stress inducers. Together, these findings demonstrate that RNASET2 regulates antioxidant tone and is required for physiological ROS responses.
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Affiliation(s)
- G Caputa
- Diabetic Cardiovascular Disease Center, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - S Zhao
- Diabetic Cardiovascular Disease Center, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - A E G Criado
- Diabetic Cardiovascular Disease Center, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - D S Ory
- Diabetic Cardiovascular Disease Center, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - J G Duncan
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - J E Schaffer
- Diabetic Cardiovascular Disease Center, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
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Dryg ID, Ward MP, Qing KY, Mei H, Schaffer JE, Irazoqui PP. Magnetically Inserted Neural Electrodes: Tissue Response and Functional Lifetime. IEEE Trans Neural Syst Rehabil Eng 2015; 23:562-71. [DOI: 10.1109/tnsre.2015.2399856] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Schaffer JE, Nauman EA, Stanciu LA. Cold drawn bioabsorbable ferrous and ferrous composite wires: an evaluation of in vitro vascular cytocompatibility. Acta Biomater 2013; 9:8574-84. [PMID: 22885027 DOI: 10.1016/j.actbio.2012.07.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 06/22/2012] [Accepted: 07/30/2012] [Indexed: 11/16/2022]
Abstract
A systematic approach is applied to quantify the impact of bioabsorbable metals on human vascular endothelial cells (EC) and aortic smooth muscle cells (SMC) with the aim of optimizing bioabsorbable endovascular stent development. Composite wires comprising novel combinations of Fe, Mn, Mg, and Zn were produced and fabricated into tubular mesh stents. The stents were incubated with primary EC in order to assess attachment and cell proliferation. Migration of SMCs from the vessel medial wall to the target lesion site following recanalization of an atherosclerotic artery is important in the process of neointimal hyperplasia. Metal ion species were assayed for their impact on cell migration and survival at concentrations ranging from 0.037 to 10 mM. An MTT-based assay was used to assess cytotoxicity after insult with various metal ion concentrations. Fe(2+) and Fe(3+) ion species were found to repress the migration of SMCs across a porous polycarbonate track etch membrane at concentrations of 1 mM. Mn(2+) promoted SMC migration at a concentration of 1 mM, however, this effect was quenched when Fe(2+) was included. Mg(2+) was found to significantly increase SMC migration at concentrations above 1 mM. Cell survival was not reduced after 24 h insult with concentrations of Mg(2+) up to 10 mM. LD50 concentrations of greater than 1 mM were found for Mg(2+), Fe(2+), Fe(3+), and Fe(2+) with 35 wt.% Mn(2+). Significantly greater numbers of EC attached to bioabsorbable metal species compared with 316L stainless steel. Good EC coverage and proliferation were observed for all tested materials up to 120 h.
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Affiliation(s)
- Jeremy E Schaffer
- Fort Wayne Metals, Research and Development, 9609 Ardmore Avenue, Fort Wayne, IN 46809, USA.
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11
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Schaffer JE. Nanocrystalline material with gigacycle fatigue life. Med Device Technol 2007; 18:12-16. [PMID: 18075128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A processing technology has been developed that can be applied to many different fine wire medical alloys to improve their fatigue properties. This technology has been used to process a low inclusion alloy, 35 cobalt-35 nitinol-20 chromium-10 Molybdenum (ASTM F562 chemistry), hereinafter referred to as System A. After processing, this ultra fine microstructure exhibited relatively high yield strength, good axial ductility and a fatigue limit of 1 GPa at a fatigue lifetime that exceeded 100 million cycles, as reported here.
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Affiliation(s)
- Jeremy E Schaffer
- Fort Wayne Metals Research Products Corporation, Fort Wayne, Indiana 46809, USA.
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12
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Frolov A, Srivastava K, Daphna-Iken D, Traub LM, Schaffer JE, Ory DS. Cholesterol overload promotes morphogenesis of a Niemann-Pick C (NPC)-like compartment independent of inhibition of NPC1 or HE1/NPC2 function. J Biol Chem 2001; 276:46414-21. [PMID: 11571306 DOI: 10.1074/jbc.m108099200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol accumulation in an aberrant endosomal/lysosomal compartment is the hallmark of Niemann-Pick type C (NPC) disease. To gain insight into the etiology of the NPC compartment, we studied a novel Chinese hamster ovary cell mutant that was identified through a genetic screen and phenocopies the NPC1 mutation. We show that the M87 mutant harbors a mutation in a gene distinct from the NPC1 and HE1/NPC2 disease genes. M87 cells have increased total cellular cholesterol with accumulation in an aberrant compartment that contains LAMP-1, LAMP-2, and NPC1, but not CI-MPR, similar to the cholesterol-rich compartment in NPC mutant cells. We demonstrate that low-density lipoprotein receptor activity is increased 3-fold in the M87 mutant, and likely contributes to accumulation of excess cholesterol. In contrast to NPC1-null cells, the M87 mutant exhibits normal rates of delivery of endosomal cholesterol to the endoplasmic reticulum and to the plasma membrane. The preserved late endosomal function in the M87 mutant is associated with the presence of NPC1-containing multivesicular late endosomes and supports a role for these multivesicular late endosomes in the sorting and distribution of cholesterol. Our findings implicate cholesterol overload in the formation of an NPC-like compartment that is independent of inhibition of NPC1 or HE1/NPC2 function.
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Affiliation(s)
- A Frolov
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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13
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Abstract
The murine fatty acid transport protein (FATP1) was identified in an expression cloning screen for proteins that facilitate transport of fatty acids across the plasma membranes of mammalian cells. Hydropathy analysis of this protein suggests a model in which FATP1 has multiple membrane-spanning domains. To test this model, we inserted a hemagglutinin epitope tag at the amino terminus or a FLAG tag at the carboxyl terminus of the FATP1 cDNA and expressed these constructs in NIH 3T3 cells. Both tagged constructs produce proteins of the expected molecular masses and are functional in fatty acid import assays. Indirect immunofluorescence studies with selective permeabilization conditions and protease protection studies of sealed membrane vesicles from cells expressing epitope-tagged FATP1 were performed. These experiments show that the extreme amino terminus of tagged FATP1 is oriented toward the extracellular space, whereas the carboxyl terminus faces the cytosol. Additionally, enhanced green fluorescent protein fusion constructs containing predicted membrane-associated or soluble portions of FATP1 were expressed in Cos7 cells and analyzed by immunofluorescence and subcellular fractionation. These experiments demonstrate that amino acids 1-51, 52-100, and 101-190 contain signals for integral association with the membrane, whereas residues 258-313 and 314-475 are only peripherally membrane-associated. Amino acid residues 191-257 and 476-646 do not direct membrane association and likely face the cytosol. Taken together, these data support a model of FATP1 as a polytopic membrane protein with at least one transmembrane and multiple membrane-associated domains. This study provides the first experimental evidence for topology of a member of the family of plasma membrane fatty acid transport proteins.
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Affiliation(s)
- S E Lewis
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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14
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Abstract
Cytotoxic accumulation of long chain fatty acids has been proposed to play an important role in the pathogenesis of diabetes mellitus and heart disease. To explore the mechanism of cellular lipotoxicity, we cultured Chinese hamster ovary cells in the presence of media supplemented with fatty acid. The saturated fatty acid palmitate, but not the monounsaturated fatty acid oleate, induced programmed cell death as determined by annexin V positivity, caspase 3 activity, and DNA laddering. De novo ceramide synthesis increased 2.4-fold with palmitate supplementation; however, this was not required for palmitate-induced apoptosis. Neither biochemical nor genetic inhibition of de novo ceramide synthesis arrested apoptosis in Chinese hamster ovary cells in response to palmitate supplementation. Rather, our data suggest that palmitate-induced apoptosis occurs through the generation of reactive oxygen species. Fluorescence of an oxidant-sensitive probe was increased 3.5-fold with palmitate supplementation indicating that production of reactive intermediates increased. In addition, palmitate-induced apoptosis was blocked by pyrrolidine dithiocarbamate and 4,5-dihydroxy-1,3-benzene-disulfonic acid, two compounds that scavenge reactive intermediates. These studies suggest that generation of reactive oxygen species, independent of ceramide synthesis, is important for the lipotoxic response and may contribute to the pathogenesis of diseases involving intracellular lipid accumulation.
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Affiliation(s)
- L L Listenberger
- Center for Cardiovascular Research, Departments of Internal Medicine, Molecular Biology, and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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15
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Abstract
Inherited and acquired cardiomyopathies are associated with marked intracellular lipid accumulation in the heart. To test the hypothesis that mismatch between myocardial fatty acid uptake and utilization leads to the accumulation of cardiotoxic lipid species, and to establish a mouse model of metabolic cardiomyopathy, we generated transgenic mouse lines that overexpress long-chain acyl-CoA synthetase in the heart (MHC-ACS). This protein plays an important role in vectorial fatty acid transport across the plasma membrane. MHC-ACS mice demonstrate cardiac-restricted expression of the transgene and marked cardiac myocyte triglyceride accumulation. Lipid accumulation is associated with initial cardiac hypertrophy, followed by the development of left-ventricular dysfunction and premature death. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and cytochrome c release in transgenic hearts suggest that cardiac myocyte death occurs, in part, by lipid-induced programmed cell death. Taken together, our data demonstrate that fatty acid uptake/utilization mismatch in the heart leads to accumulation of lipid species toxic to cardiac myocytes. This novel mouse model will provide insight into the role of perturbations in myocardial lipid metabolism in the pathogenesis of inherited and acquired forms of heart failure.
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Affiliation(s)
- H C Chiu
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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16
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Millard EE, Srivastava K, Traub LM, Schaffer JE, Ory DS. Niemann-pick type C1 (NPC1) overexpression alters cellular cholesterol homeostasis. J Biol Chem 2000; 275:38445-51. [PMID: 10964915 DOI: 10.1074/jbc.m003180200] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Niemann-Pick type C1 (NPC1) protein is a key participant in intracellular trafficking of low density lipoprotein cholesterol, but its role in regulation of sterol homeostasis is not well understood. To characterize further the function of NPC1, we generated stable Chinese hamster ovary (CHO) cell lines overexpressing the human NPC1 protein (CHO/NPC1). NPC1 overexpression increases the rate of trafficking of low density lipoprotein cholesterol to the endoplasmic reticulum and the rate of delivery of endosomal cholesterol to the plasma membrane (PM). CHO/NPC1 cells exhibit a 1.5-fold increase in total cellular cholesterol and up to a 2.9-fold increase in PM cholesterol. This increase in PM cholesterol is closely paralleled by a 3-fold increase in de novo cholesterol synthesis. Inhibition of cholesterol synthesis results in marked redistribution of PM cholesterol to intracellular sites, suggesting an unsuspected role for NPC1 in internalization of PM cholesterol. Despite elevated total cellular cholesterol, CHO/NPC1 cells exhibit increased cholesterol synthesis, which may be attributable to both resistance to oxysterol suppression of sterol-regulated gene expression and to reduced endoplasmic reticulum cholesterol levels under basal conditions. Taken together, these studies provide important new insights into the role of NPC1 in the determination of the levels and distribution of cellular cholesterol.
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Affiliation(s)
- E E Millard
- Center for Cardiovascular Research, Department of Internal Medicine and the Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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17
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Stuhlsatz-Krouper SM, Bennett NE, Schaffer JE. Molecular aspects of fatty acid transport: mutations in the IYTSGTTGXPK motif impair fatty acid transport protein function. Prostaglandins Leukot Essent Fatty Acids 1999; 60:285-9. [PMID: 10471110 DOI: 10.1016/s0952-3278(99)80001-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The murine fatty acid transport protein (FATP) facilitates uptake of long chain fatty acids (LCFAs) when expressed in mammalian cells. FATP's sequence contains a highly conserved motif, IYTSGTTGXPK, also found in a number of proteins known to interact with ATP. To explore the role of this motif, we independently mutated the central serine (serine 250) and threonine (threonine 252) residues in this motif and assessed the effects of these mutations on FATP function. When expressed in fibroblasts, the FATP mutants demonstrated impaired LCFA import and impaired binding of [alpha-32P]8-azido-ATP (azido-ATP) compared with wild-type FATP. These results suggest that serine 250 and threonine 252 are critical for FATP function and that the mechanism of action of FATP involves nucleotide binding which is dependent on these residues.
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Affiliation(s)
- S M Stuhlsatz-Krouper
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110-1010, USA
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18
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Gargiulo CE, Stuhlsatz-Krouper SM, Schaffer JE. Localization of adipocyte long-chain fatty acyl-CoA synthetase at the plasma membrane. J Lipid Res 1999; 40:881-92. [PMID: 10224157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Long-chain fatty acyl-CoA synthetase (FACS) catalyzes esterification of long-chain fatty acids (LCFAs) with coenzyme A (CoA), the first step in fatty acid metabolism. FACS has been shown to play a role in LCFA import into bacteria and implicated to function in mammalian cell LCFA import. In the present study, we demonstrate that FACS overexpression in fibroblasts increases LCFA uptake, and overexpression of both FACS and the fatty acid transport protein (FATP) have synergistic effects on LCFA uptake. To explore how FACS contributes to LCFA import, we examined the subcellular location of this enzyme in 3T3-L1 adipocytes which natively express this protein and which efficiently take up LCFAs. We demonstrate for the first time that FACS is an integral membrane protein. Subcellular fractionation of adipocytes by differential density centrifugation reveals immunoreactive and enzymatically active FACS in several membrane fractions, including the plasma membrane. Immunofluorescence studies on adipocyte plasma membrane lawns confirm that FACS resides at the plasma membrane of adipocytes, where it co-distributes with FATP. Taken together, our data support a model in which imported LCFAs are immediately esterified at the plasma membrane upon uptake, and in which FATP and FACS function coordinately to facilitate LCFA movement across the plasma membrane of mammalian cells.
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Affiliation(s)
- C E Gargiulo
- Center for Cardiovascular Research, Department of Internal Medicine and Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO, 63110-1010, USA
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19
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Stuhlsatz-Krouper SM, Bennett NE, Schaffer JE. Substitution of alanine for serine 250 in the murine fatty acid transport protein inhibits long chain fatty acid transport. J Biol Chem 1998; 273:28642-50. [PMID: 9786857 DOI: 10.1074/jbc.273.44.28642] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The murine fatty acid transport protein (FATP) was identified on the basis of its ability to facilitate uptake of long chain fatty acids (LCFAs) when expressed in mammalian cells. To delineate FATP domains important for transport function, we cloned the human heart FATP ortholog. Comparison of the human, murine, and yeast amino acid sequences identified a highly conserved motif, IYTSGTTGXPK, also found in a number of proteins that form adenylated intermediates. We demonstrate that depletion of intracellular ATP dramatically reduces FATP-mediated LCFA uptake. Furthermore, wild-type FATP specifically binds [alpha-32P]azido-ATP. Introduction of a serine to alanine substitution (S250A) in the IYTSGTTGXPK motif produces an appropriately expressed and metabolized mutant FATP that demonstrates diminished LCFA transport function and decreased [alpha-32P]azido-ATP binding. These results are consistent with a mechanism of action for FATP involving ATP binding that is dependent on serine 250 of the IYTSGTTGXPK motif.
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Affiliation(s)
- S M Stuhlsatz-Krouper
- Center for Cardiovascular Research, Department of Internal Medicine and the Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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20
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Hui TY, Frohnert BI, Smith AJ, Schaffer JE, Bernlohr DA. Characterization of the murine fatty acid transport protein gene and its insulin response sequence. J Biol Chem 1998; 273:27420-9. [PMID: 9765271 DOI: 10.1074/jbc.273.42.27420] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fatty acid transport protein (FATP) was identified by expression cloning strategies (Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436) and shown by transfection analysis to catalyze the transfer of long-chain fatty acids across the plasma membrane of cells. It is expressed highly in tissues exhibiting rapid fatty acid metabolism such as skeletal muscle, heart, and adipose. FATP mRNA levels are down-regulated by insulin in cultured 3T3-L1 adipocytes and up-regulated by nutrient depletion in murine adipose tissue (Man, M. Z., Hui, T. Y., Schaffer, J. E., Lodish, H. F., and Bernlohr, D. A. (1996) Mol. Endocrinol. 10, 1021-1028). To determine the molecular mechanism of insulin regulation of FATP transcription, we have isolated the murine FATP gene and its 5'-flanking sequences. The FATP gene spans approximately 16 kilobases and contains 13 exons, of which exon 2 is alternatively spliced. S1 nuclease and RNase protection assays revealed the presence of multiple transcription start sites; the DNA sequence upstream of the predominant transcription start sites lacks a typical TATA box. By transient transfection assays in 3T3-L1 adipocytes, the inhibitory action of insulin on FATP transcription was localized to a cis-acting element with the sequence 5'-TGTTTTC-3' from -1347 to -1353. This sequence is very similar to the insulin response sequence found in the regulatory region of other genes negatively regulated by insulin such as those encoding phosphoenolpyruvate carboxykinase, tyrosine aminotransferase, and insulin-like growth factor-binding protein 1. Fluorescence in situ hybridization analysis revealed that the murine FATP gene is localized to chromosome 8, band 8B3.3. Interestingly, this region of chromosome 8 contains a cluster of three other genes important for fatty acid homeostasis, lipoprotein lipase, the mitochondrial uncoupling protein 1 (UCP1) and sterol regulatory element-binding protein 1. These results characterize the murine FATP gene and its insulin responsiveness as well as present a framework for future studies of its role in lipid metabolism, obesity, and type II diabetes mellitus.
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Affiliation(s)
- T Y Hui
- Department of Biochemistry, University of Minnesota, St. Paul, Minnesota 55108, USA
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21
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Abstract
A cDNA encoding a novel fatty acid transport protein (FATP) was identified recently using expression cloning methodologies. We have studied the expression of FATP in differentiating 3T3-L1 cells and adipose tissue in vivo. When 3T3-L1 preadipocytes are treated with a combination of methylisobutylxanthine, dexamethasone, and insulin to induce differentiation, the abundance of FATP mRNA decreases within 24 h to less than one-third that of preadipocytes and increases subsequently, such that mature adipocytes have 5-7 times more FATP mRNA than fibroblastic precursors. In fully differentiated 3T3-L1 adipocytes, insulin alone is sufficient to down-regulate FATP mRNA levels 10-fold. The concentration of insulin necessary for half-maximal repression (I0.5) is approximately 1 nM and is specific for insulin; insulin-like growth factor I (IGF-I) has little effect at similar concentrations. Kinetic analysis indicates that the reduction in expression of FATP mRNA by insulin is rapid (t1/2 = approximately 4 h) and reversible upon withdrawal of insulin. The half-lives of FATP mRNA are 2.9 h and 4.4 h in the absence and presence of insulin, respectively. The insulin-mediated decrease in FATP steady state mRNA level correlates with a decrease in its transcription rate as measured by nuclear run-on transcription assay. To determine whether physiological conditions that alter insulin concentration in vivo affect adipose FATP levels, feeding/fasting studies are employed. Fasting of C57BL/6J mice for 48 h results in an 11-fold up-regulation of FATP mRNA expression in adipose tissue. Refeeding of fasted animals for 72 h results in a return of FATP mRNA to basal levels. In sum, these results indicate that the expression of FATP gene is negatively regulated by insulin at the transcriptional level in cultured adipocytes and that transporter mRNA expression in murine adipose tissue is altered in a manner consistent with insulin being a negative regulator of gene activity.
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Affiliation(s)
- M Z Man
- Whitehead Institute for Biomedical Research, Boston, Massachusetts, USA
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22
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Schaffer JE. A novel adipocyte long chain fatty acid transport protein. Eur J Med Res 1996; 1:176-80. [PMID: 9386266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Uptake of long chain fatty acids (LCFAs) is a critical function of eukaryotic cells. In the past, a diffusional mechanism has been proposed for passage of these hydrophobic molecules across the plasma membrane. I have recently used an expression cloning strategy to identify a novel integral plasma membrane fatty acid transport protein (FATP), which functions as an LCFA transporter. FATP may play a pivotal role in alterations of cellular metabolism which occur in several pathophysiologic states.
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Affiliation(s)
- J E Schaffer
- Washington University School of Medicine, 660 South Euclid Avenue, Box 8086, St. Louis, MO 63110, USA
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23
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Abstract
Long chain fatty acids (LCFAs) are an important energy substrate used by cardiac myocytes and other cells, but the mechanism whereby these molecules cross the plasma membrane is poorly understood. We used an expression cloning strategy and a cDNA library from 3T3-L1 adipocytes to identify a cDNA that, when expressed in cultured cells, augments uptake of LCFAs. This cDNA encodes a novel 646 amino acid fatty acid transport protein (FATP) with six predicted membrane-spanning regions and that is integrally associated with membranes. Immunocytochemistry and subcellular fractionation of 3T3-L1 adipocytes show that FATP is localized to the plasma membrane. We propose that FATP is a plasma membrane transporter for LCFAs.
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Affiliation(s)
- J E Schaffer
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142
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24
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Abstract
We used traditional crude population denominators and four different definitions of sexual activity to calculate progressively more refined gonorrhea rates among reproductive age women. Refining denominators to take sexual activity into account had the largest impact on morbidity rates for young women. Traditional denominators severely underestimate gonorrhea rates in teenagers, and understate the real magnitude of gonorrhea risk among sexually active teenagers.
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Affiliation(s)
- S O Aral
- Centers for Disease Control, Division of Sexually Transmitted Diseases, Atlanta, GA 30333
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