1
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Crabtree AA, Bates FS, Hackel BJ. Concentration Threshold for Membrane Protection by PEO-PPO Block Copolymers with Variable Molecular Architectures. ACS APPLIED POLYMER MATERIALS 2022; 4:3259-3269. [PMID: 36777189 PMCID: PMC9907980 DOI: 10.1021/acsapm.1c01807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Poloxamer 188, a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer, protects cell membranes in several injury models. However, the nature of the copolymer/membrane interaction and the mechanism of membrane protection remain unknown. Systematic variations of the block copolymer architecture - including PPO-PEO-PPO triblocks and PPO-PEO diblocks - were used to probe the mechanism and evaluate the potential for alternative architectures to yield superior protection. To test the polymers, murine myoblasts were subjected to an osmotic stress, and membrane integrity was quantified by measuring lactate dehydrogenase (LDH) leakage. These experiments exposed a concentration threshold effect where all tested polymers reach 50% leakage of LDH compared to a non-treated buffer only control over a narrow concentration range of 0.8-4 μM. Differences in polymer protection at lower concentrations indicate that protection increases with the PPO-PEO-PPO molecular architecture and increasing hydrophobicity.
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Affiliation(s)
| | | | - Benjamin J. Hackel
- Corresponding Author: Benjamin J. Hackel – Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, Phone: 612-624-7102,
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2
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Narez GE, Brown G, Herrick A, Ek RJ, Dejardin L, Wei F, Haut RC, Haut Donahue TL. Evaluating the Efficacy of Combined P188 Treatment and Surgical Intervention in Preventing Post-Traumatic Osteoarthritis Following a Traumatic Knee Injury. J Biomech Eng 2022; 144:1120716. [PMID: 34751734 DOI: 10.1115/1.4052564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Indexed: 11/08/2022]
Abstract
Previous studies have shown that reconstructive surgery alone following injury to the anterior cruciate ligament (ACL) does not prevent the development of post-traumatic osteoarthritis (PTOA). Poloxamer 188 (P188) has been shown to prevent cell death following trauma in both articular cartilage and meniscal tissue. This study aims to test the efficacy of single or multiple administrations of P188 in conjunction with reconstructive surgery to help prevent or delay the onset of the disease. Thirty skeletally mature rabbits underwent closed-joint trauma that resulted in ACL rupture and meniscal damage and were randomly assigned to one of four treatment groups with varying doses of P188. ACL reconstruction was then performed using an autograft from the semitendinosus tendon. Animals were euthanized 1-month following trauma, meniscal tissue was assessed for changes in morphology, mechanical properties, and proteoglycan content. Femurs and tibias were scanned using microcomputed tomography to determine changes in bone quality, architecture, and osteophyte formation. The medial meniscus experienced more damage and a decrease in the instantaneous modulus regardless of treatment group, while P188 treatment tended to limit degenerative changes in the lateral meniscus. Both lateral and medial menisci had documented decreases in the equilibrium modulus and inconsistent changes in proteoglycan content. Minimal changes were documented in the tibias and femurs, with the only significant change being the formation of osteophytes in both bones regardless of treatment group. The data suggest that P188 was able to limit some degenerative changes in the meniscus associated with PTOA and may warrant future studies.
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Affiliation(s)
- Gerardo E Narez
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003
| | - Gabriel Brown
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003
| | - Ashley Herrick
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003
| | - Ryan J Ek
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003
| | - Loic Dejardin
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824
| | - Feng Wei
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48824
| | - Roger C Haut
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48824; Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824
| | - Tammy L Haut Donahue
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003; S631 Life Sciences Laboratory, University of Massachusetts, 240 Thatcher Road, Amherst, MA 01003
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3
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Haut Donahue TL, Narez GE, Powers M, Dejardin LM, Wei F, Haut RC. A Morphological Study of the Meniscus, Cartilage and Subchondral Bone Following Closed-Joint Traumatic Impact to the Knee. Front Bioeng Biotechnol 2022; 10:835730. [PMID: 35387294 PMCID: PMC8977861 DOI: 10.3389/fbioe.2022.835730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
Post-traumatic osteoarthritis (PTOA) is a debilitating disease that is a result of a breakdown of knee joint tissues following traumatic impact. The interplay of how these tissues influence each other has received little attention because of complex interactions. This study was designed to correlate the degeneration of the menisci, cartilage and subchondral bone following an acute traumatic event that resulted in anterior cruciate ligament (ACL) and medial meniscus tears. We used a well-defined impact injury animal model that ruptures the ACL and tears the menisci. Subsequently, the knee joints underwent ACL reconstruction and morphological analyses were performed on the menisci, cartilage and subchondral bone at 1-, 3- and 6-months following injury. The results showed that the morphological scores of the medial and lateral menisci worsened with time, as did the tibial plateau and femoral condyle articular cartilage scores. The medial meniscus was significantly correlated to the medial tibial subchondral bone at 1 month (p = 0.01), and to the medial tibial cartilage at 3 months (p = 0.04). There was only one significant correlation in the lateral hemijoint, i.e., the lateral tibial cartilage to the lateral tibial subchondral bone at 6 months (p = 0.05). These data may suggest that, following trauma, the observed medial meniscal damage should be treated acutely by means other than a full or partial meniscectomy, since that procedure may have been the primary cause of degenerative changes in the underlying cartilage and subchondral bone. In addition to potentially treating meniscal damage differently, improvements could be made in optimizing treatment of acute knee trauma.
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Affiliation(s)
- T. L. Haut Donahue
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, United States
- *Correspondence: T. L. Haut Donahue,
| | - G. E. Narez
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
| | - M. Powers
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
| | - L. M. Dejardin
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, United States
| | - F. Wei
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
| | - R. C. Haut
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
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Yan W, Dai W, Cheng J, Fan Y, Wu T, Zhao F, Zhang J, Hu X, Ao Y. Advances in the Mechanisms Affecting Meniscal Avascular Zone Repair and Therapies. Front Cell Dev Biol 2021; 9:758217. [PMID: 34778268 PMCID: PMC8581462 DOI: 10.3389/fcell.2021.758217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 12/14/2022] Open
Abstract
Injuries to menisci are the most common disease among knee joint-related morbidities and cover a widespread population ranging from children and the general population to the old and athletes. Repair of the injuries in the meniscal avascular zone remains a significant challenge due to the limited intrinsic healing capacity compared to the peripheral vascularized zone. The current surgical strategies for avascular zone injuries remain insufficient to prevent the development of cartilage degeneration and the ultimate emergence of osteoarthritis (OA). Due to the drawbacks of current surgical methods, the research interest has been transferred toward facilitating meniscal avascular zone repair, where it is expected to maintain meniscal tissue integrity, prevent secondary cartilage degeneration and improve knee joint function, which is consistent with the current prevailing management idea to maintain the integrity of meniscal tissue whenever possible. Biological augmentations have emerged as an alternative to current surgical methods for meniscal avascular zone repair. However, understanding the specific biological mechanisms that affect meniscal avascular zone repair is critical for the development of novel and comprehensive biological augmentations. For this reason, this review firstly summarized the current surgical techniques, including meniscectomies and meniscal substitution. We then discuss the state-of-the-art biological mechanisms, including vascularization, inflammation, extracellular matrix degradation and cellular component that were associated with meniscal avascular zone healing and the advances in therapeutic strategies. Finally, perspectives for the future biological augmentations for meniscal avascular zone injuries will be given.
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Affiliation(s)
- Wenqiang Yan
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Wenli Dai
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Jin Cheng
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Yifei Fan
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Tong Wu
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Fengyuan Zhao
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Jiahao Zhang
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Xiaoqing Hu
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
| | - Yingfang Ao
- Department of Sports Medicine, Peking University Third Hospital, Beijing, China.,Institute of Sports Medicine of Peking University, Beijing, China.,Beijing Key Laboratory of Sports Injuries, Beijing, China
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Narez GE, Brown G, Herrick A, Ek RJ, Dejardin L, Wei F, Haut RC, Haut Donahue TL. Assessment of changes in the meniscus and subchondral bone in a novel closed-joint impact and surgical reconstruction lapine model. J Biomech 2021; 126:110630. [PMID: 34303894 DOI: 10.1016/j.jbiomech.2021.110630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/17/2021] [Accepted: 07/05/2021] [Indexed: 11/25/2022]
Abstract
Despite reconstruction surgery to repair a torn anterior cruciate ligament (ACL), patients often still show signs of post-traumatic osteoarthritis (PTOA) years following the procedure. The goal of this study was to document changes in the meniscus and subchondral bone due to closed-joint impact and surgical reconstruction in a lapine model. Animals received insult to the joint followed by surgical reconstruction of the ACL and partial meniscectomy. Following euthanasia of the animals at 1, 3, and 6-months post-impact, meniscal tissue was assessed for changes in morphology, mechanical properties and proteoglycan content. Femurs and tibias were scanned via micro-computed tomography to determine changes in bone quality, morphometry, and formation of osteophytes. Both the lateral and medial menisci showed severe degradation and tearing at all-time points, with higher degree of degeneration being observed at 6-months. Decreases in both the instantaneous and equilibrium modulus were documented in both menisci. Minimal changes were found in bone quality and morphometry, with most change documented in the tibia. Bones from the reconstructed limbs showed large volumes of osteophyte formations, with an increase in volume over time. The initial changes that were representative of PTOA may have been limited to the meniscus, but at later time points consistent changes due to the disease were seen in both tissues. This study, which builds on a previous study by this laboratory, suggests that the addition of surgical reconstruction of the ACL to our model was not sufficient to prevent the development of PTOA.
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Affiliation(s)
- Gerardo E Narez
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, USA
| | - Gabriel Brown
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, USA
| | - Ashley Herrick
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, USA
| | - Ryan J Ek
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, USA
| | - Loic Dejardin
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - Feng Wei
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Roger C Haut
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA; Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
| | - Tammy L Haut Donahue
- Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA, USA.
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6
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Narez GE, Wei F, Dejardin L, Haut RC, Haut Donahue TL. A single dose of P188 prevents cell death in meniscal explants following impact injury. J Mech Behav Biomed Mater 2021; 117:104406. [PMID: 33621866 DOI: 10.1016/j.jmbbm.2021.104406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/06/2020] [Accepted: 02/12/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine the efficacy of single and multiple administrations of Poloxamer 188 (P188) in saving meniscal cells following an injurious impact. METHODS Meniscal explants were harvested from both the lateral and medial menisci of Flemish Giant rabbits. After a 24-h incubation period, explants were subjected to 50% impact strain to simulate traumatic joint injury, and the explants were then placed in media with or without supplemented P188. Temporal administrations of P188 over a 14-day period were given based on one of 6 different treatments regimes. Over the 14-day period, explants were cyclically loaded to 10% strain at 1 Hz for 1 h per day, five days a week. Cell viability was assessed on day 14, with the remainder of the tissue being fixed to determine cell apoptosis levels and proteoglycan changes via histology. RESULTS The injurious impact proved to produce significant levels of cell death in meniscal explants. The ability of P188 to prevent cell death was not affected by the number of P188 doses (single versus multiple). P188 treatment proved to maintain cell viability levels comparable to those from unimpacted explants. There were no significant changes in cell apoptosis or proteoglycan coverage in the tissues over a 14-day period for any group, all treatment groups were statistically similar to the unimpacted explants. CONCLUSION A single dose of P188 following impact is all that is necessary to inhibit cell death in the meniscus following a traumatic impact. Thus, orthopaedic surgeons may choose to administer P188 in addition to treating any other acute damage due to a traumatic load to the knee, such as anterior cruciate ligament rupture, although more in depth in vivo studies are necessary.
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Affiliation(s)
- Gerardo E Narez
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA
| | - Feng Wei
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Loic Dejardin
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - Roger C Haut
- Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Tammy L Haut Donahue
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA.
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Houang EM, Bartos J, Hackel BJ, Lodge TP, Yannopoulos D, Bates FS, Metzger JM. Cardiac Muscle Membrane Stabilization in Myocardial Reperfusion Injury. JACC Basic Transl Sci 2019; 4:275-287. [PMID: 31061929 PMCID: PMC6488758 DOI: 10.1016/j.jacbts.2019.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/11/2019] [Accepted: 01/26/2019] [Indexed: 12/11/2022]
Abstract
The phospholipid bilayer membrane that surrounds each cell in the body represents the first and last line of defense for preserving overall cell viability. In several forms of cardiac and skeletal muscle disease, deficits in the integrity of the muscle membrane play a central role in disease pathogenesis. In Duchenne muscular dystrophy, an inherited and uniformly fatal disease of progressive muscle deterioration, muscle membrane instability is the primary cause of disease, including significant heart disease, for which there is no cure or highly effective treatment. Further, in multiple clinical forms of myocardial ischemia-reperfusion injury, the cardiac sarcolemma is damaged and this plays a key role in disease etiology. In this review, cardiac muscle membrane stability is addressed, with a focus on synthetic block copolymers as a unique chemical-based approach to stabilize damaged muscle membranes. Recent advances using clinically relevant small and large animal models of heart disease are discussed. In addition, mechanistic insights into the copolymer-muscle membrane interface, featuring atomistic, molecular, and physiological structure-function approaches are highlighted. Collectively, muscle membrane instability contributes significantly to morbidity and mortality in prominent acquired and inherited heart diseases. In this context, chemical-based muscle membrane stabilizers provide a novel therapeutic approach for a myriad of heart diseases wherein the integrity of the cardiac muscle membrane is at risk.
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Affiliation(s)
- Evelyne M. Houang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Jason Bartos
- Department of Medicine-Cardiovascular Division, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Benjamin J. Hackel
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota
| | - Timothy P. Lodge
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota
| | - Demetris Yannopoulos
- Department of Medicine-Cardiovascular Division, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Frank S. Bates
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota
| | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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8
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Houang EM, Sham YY, Bates FS, Metzger JM. Muscle membrane integrity in Duchenne muscular dystrophy: recent advances in copolymer-based muscle membrane stabilizers. Skelet Muscle 2018; 8:31. [PMID: 30305165 PMCID: PMC6180502 DOI: 10.1186/s13395-018-0177-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/13/2018] [Indexed: 02/07/2023] Open
Abstract
The scientific premise, design, and structure-function analysis of chemical-based muscle membrane stabilizing block copolymers are reviewed here for applications in striated muscle membrane injury. Synthetic block copolymers have a rich history and wide array of applications from industry to biology. Potential for discovery is enabled by a large chemical space for block copolymers, including modifications in block copolymer mass, composition, and molecular architecture. Collectively, this presents an impressive chemical landscape to leverage distinct structure-function outcomes. Of particular relevance to biology and medicine, stabilization of damaged phospholipid membranes using amphiphilic block copolymers, classified as poloxamers or pluronics, has been the subject of increasing scientific inquiry. This review focuses on implementing block copolymers to protect fragile muscle membranes against mechanical stress. The review highlights interventions in Duchenne muscular dystrophy, a fatal disease of progressive muscle deterioration owing to marked instability of the striated muscle membrane. Biophysical and chemical engineering advances are presented that delineate and expand upon current understanding of copolymer-lipid membrane interactions and the mechanism of stabilization. The studies presented here serve to underscore the utility of copolymer discovery leading toward the therapeutic application of block copolymers in Duchenne muscular dystrophy and potentially other biomedical applications in which membrane integrity is compromised.
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Affiliation(s)
- Evelyne M Houang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Yuk Y Sham
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.,University of Minnesota Informatics Institute, MN, USA.,Bioinformatics and Computational Biology Program, University of Minnesota, MN, USA
| | - Frank S Bates
- Department of Chemical Engineering and Materials Science, University of Minnesota, MN, USA
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
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9
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Kim M, Haman KJ, Houang EM, Zhang W, Yannopoulos D, Metzger JM, Bates FS, Hackel BJ. PEO-PPO Diblock Copolymers Protect Myoblasts from Hypo-Osmotic Stress In Vitro Dependent on Copolymer Size, Composition, and Architecture. Biomacromolecules 2017; 18:2090-2101. [PMID: 28535058 DOI: 10.1021/acs.biomac.7b00419] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Poloxamer 188, a triblock copolymer of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), protects cellular membranes from various stresses. Though numerous block copolymer variants exist, evaluation of alternative architecture, composition, and size has been minimal. Herein, cultured murine myoblasts are exposed to the stresses of hypotonic shock and isotonic recovery, and membrane integrity was evaluated by quantifying release of lactate dehydrogenase. Comparative evaluation of a systematic set of PEO-PPO diblock and PEO-PPO-PEO triblock copolymers demonstrates that the diblock architecture can be protective in vitro. Short PPO blocks hinder protection with >9 PPO units needed for protection at 150 μM and >16 units needed at 14 μM. Addition of a tert-butyl end group enhances protection at reduced concentration. When the end group and PPO length are fixed, increasing the PEO length improves protection. This systematic evaluation establishes a new in vitro screening tool for evaluating membrane-sealing amphiphiles and provides mechanistic insight to guide future copolymer design for membrane stabilization in vivo.
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Affiliation(s)
- Mihee Kim
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Karen J Haman
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Evelyne M Houang
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Wenjia Zhang
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Demetris Yannopoulos
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Joseph M Metzger
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Frank S Bates
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Benjamin J Hackel
- Department of Chemical Engineering and Materials Science, ‡Department of Integrative Biology and Physiology, and §Department of Medicine, Cardiovascular Division, University of Minnesota , Minneapolis, Minnesota 55455, United States
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10
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Levillain A, Magoariec H, Boulocher C, Decambron A, Viateau V, Hoc T. Viscoelastic properties of rabbit osteoarthritic menisci: A correlation with matrix alterations. J Mech Behav Biomed Mater 2016; 65:1-10. [PMID: 27543842 DOI: 10.1016/j.jmbbm.2016.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/23/2016] [Accepted: 08/05/2016] [Indexed: 01/11/2023]
Abstract
The aim of this study was to evaluate the effect of early osteoarthritis (OA) on the viscoelastic properties of rabbit menisci and to correlate the mechanical alterations with the microstructural changes. Anterior Cruciate Ligament Transection (ACLT) was performed in six male New-Zealand White rabbits on the right knee joint. Six healthy rabbits served as controls. Menisci were removed six weeks after ACLT and were graded macroscopically. Indentation-relaxation tests were performed in the anterior and posterior regions of the medial menisci. The collagen fibre organization and glycosaminoglycan (GAG) content were assessed by biphotonic confocal microscopy and histology, respectively. OA menisci displayed severe macroscopic lesions compared with healthy menisci (p=0.009). Moreover, the instantaneous and equilibrium moduli, which were 2.9±1.0MPa and 0.60±0.18MPa in the anterior region of healthy menisci, respectively, decreased significantly (p=0.03 and p=0.004, respectively) in OA menisci by 55% and 57%, respectively, indicating a global decrease in meniscal stiffness in this region. The equilibrium modulus alone decreased significantly (p=0.04) in the posterior region, going from 0.60±0.18MPa to 0.26±012MPa. This induced a loss of tissue elasticity. These mechanical changes were associated in the posterior region with a structural disruption of the superficial layers, from which the tie fibres emanate, and with a decrease in the GAG content in the anterior region. Consequently, the circumferential collagen fibres of the deep zone were dissociated and the collagen bundles were less compact. Our results demonstrate the strong meniscal modifications induced by ACLT at an early stage of OA and highlight the relationship between structural and chemical matrix alterations and mechanical properties.
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Affiliation(s)
- A Levillain
- LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36av Guy de Collongue, 69134 Ecully Cedex, France
| | - H Magoariec
- LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36av Guy de Collongue, 69134 Ecully Cedex, France
| | - C Boulocher
- Research unit ICE, UPSP 2011.03.101, Université de Lyon, veterinary campus of VetAgro Sup, 69 280 Marcy l'Etoile, France
| | - A Decambron
- B2OA, UMR 7052, ENVA, 7Avenue du Général de Gaulle, 94700 Maisons-Alfort, France
| | - V Viateau
- B2OA, UMR 7052, ENVA, 7Avenue du Général de Gaulle, 94700 Maisons-Alfort, France
| | - T Hoc
- LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36av Guy de Collongue, 69134 Ecully Cedex, France.
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