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Zinc insulin hexamer loaded alginate zinc hydrogel: preparation, characterization and in vivo hypoglycemic ability. Eur J Pharm Biopharm 2022; 179:173-181. [PMID: 36087882 DOI: 10.1016/j.ejpb.2022.08.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/22/2022] [Accepted: 08/27/2022] [Indexed: 11/21/2022]
Abstract
Alginate zinc hydrogel loaded with zinc insulin hexamer was prepared and characterized for oral insulin administration. The hydrogel was fabricated by dripping zinc insulin hexamer into sodium alginate solution and followed by crosslinking by zinc chloride. SEM image reveals the zinc insulin hexamer was integrated into the matrix of hydrogel. Zinc insulin hexamer loaded hydrogel shows no obvious cytotoxicity to both HT29 and Caco-2 cells. The developed hydrogel retards the burst release of insulin in simulated gastric fluid but promotes the release when in simulated intestinal fluid. In the diabetic mice, zinc insulin hexamer loaded alginate hydrogel demonstrates significant and prolonged hypoglycemic effect.
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2
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Yin H, Li J, Huang H, Wang Y, Qian X, Ren J, Xue F, Dai J, Tang F. Microencapsulated phages show prolonged stability in gastrointestinal environments and high therapeutic efficiency to treat Escherichia coli O157:H7 infection. Vet Res 2021; 52:118. [PMID: 34521472 PMCID: PMC8439058 DOI: 10.1186/s13567-021-00991-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Abstract
Escherichia coli (E. coli) O157:H7 bacterial infection causes severe disease in mammals and results in substantial economic losses worldwide. Due to the development of antibiotic resistance, bacteriophage (phage) therapy has become an alternative to control O157:H7 infection. However, the therapeutic effects of phages are frequently disappointing because of their low resistance to the gastrointestinal environment. In this study, to improve the stability of phages in the gastrointestinal tract, E. coli O157:H7 phages were microencapsulated and their in vitro stability and in vivo therapeutic efficiency were investigated. The results showed that compared to free phages, the resistance of microencapsulated phages to simulated gastric fluid and bile salts significantly increased. The microencapsulated phages were efficiently released into simulated intestinal fluid, leading to a better therapeutic effect in rats infected with E. coli O157:H7 compared to the effects of the free phages. In addition, the microencapsulated phages were more stable during storage than the free phages, showing how phage microencapsulation can play an essential role in phage therapy.
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Affiliation(s)
- Hanjie Yin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jing Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Haosheng Huang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuxin Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xinjie Qian
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianluan Ren
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Feng Xue
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianjun Dai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,China Pharmaceutical University, Nanjing, China
| | - Fang Tang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
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3
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Nano- and microstructural evolution of alginate beads in simulated gastrointestinal fluids. Impact of M/G ratio, molecular weight and pH. Carbohydr Polym 2019; 223:115121. [DOI: 10.1016/j.carbpol.2019.115121] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/12/2019] [Accepted: 07/21/2019] [Indexed: 11/22/2022]
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4
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Vaghasiya K, Eram A, Sharma A, Ray E, Adlakha S, Verma RK. Alginate Microspheres Elicit Innate M1-Inflammatory Response in Macrophages Leading to Bacillary Killing. AAPS PharmSciTech 2019; 20:241. [PMID: 31250260 DOI: 10.1208/s12249-019-1458-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/13/2019] [Indexed: 12/20/2022] Open
Abstract
Particulate drug delivery systems (PDDS) have been broadly explored as platforms for delivery of drugs, enzymes, cells, and vaccines for pharmaceutical applications. Studies suggest that microspheres (MS) can stimulate innate immune cells even without a drug payload; however, less is known regarding how they impact host cells in dealing with the bacillary infection. We examined the role of drug-free inhalable alginate microspheres (A-MS) on phagocytosis efficiency and subsequent immune cell activation in Escherichia coli-infected THP-1-derived macrophages. Alginate particles have been widely investigated as carriers for prolonged delivery of bioactive (i.e., drugs, diagnostics, and vaccines). A-MS were fabricated by industry scalable spray-congealing process using divalent cation-induced gelification. E. coli-infected macrophages (multiplicity of infection (MOI 1:10) were treated with drug-free A-MS, where we found a consistent moderate reduction in bacillary viability. Particles were more efficiently and rapidly phagocytized by infected macrophages as compared with normal macrophage cells. Subsequently, A-MS induced markers of M1 macrophage responses and stimulated the processing and secretion of pro-inflammatory cytokines (IL-6, IL-12). It also notably augmented the generation of reactive oxygen species (ROS) and nitric oxide (NO) in infected cells. Results illustrate that, the blank A-MS (without a drug payload) able to moderately check the growth of intracellular E. coli (without significant cytotoxicity) by modulating the M1 inflammatory response by host cells. This "added value" can be utilized in the design and development of therapeutic system with the additional advantage of immune-modulatory activity, in addition to serving as a drug carrier.
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5
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Hu S, de Vos P. Polymeric Approaches to Reduce Tissue Responses Against Devices Applied for Islet-Cell Encapsulation. Front Bioeng Biotechnol 2019; 7:134. [PMID: 31214587 PMCID: PMC6558039 DOI: 10.3389/fbioe.2019.00134] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/20/2019] [Indexed: 12/15/2022] Open
Abstract
Immunoisolation of pancreatic islets is a technology in which islets are encapsulated in semipermeable but immunoprotective polymeric membranes. The technology allows for successful transplantation of insulin-producing cells in the absence of immunosuppression. Different approaches of immunoisolation are currently under development. These approaches involve intravascular devices that are connected to the bloodstream and extravascular devices that can be distinguished in micro- and macrocapsules and are usually implanted in the peritoneal cavity or under the skin. The technology has been subject of intense fundamental research in the past decade. It has co-evolved with novel replenishable cell sources for cure of diseases such as Type 1 Diabetes Mellitus that need to be protected for the host immune system. Although the devices have shown significant success in animal models and even in human safety studies most technologies still suffer from undesired tissue responses in the host. Here we review the past and current approaches to modulate and reduce tissue responses against extravascular cell-containing micro- and macrocapsules with a focus on rational choices for polymer (combinations). Choices for polymers but also choices for crosslinking agents that induce more stable and biocompatible capsules are discussed. Combining beneficial properties of molecules in diblock polymers or application of these molecules or other anti-biofouling molecules have been reviewed. Emerging are also the principles of polymer brushes that prevent protein and cell-adhesion. Recently also immunomodulating biomaterials that bind to specific immune receptors have entered the field. Several natural and synthetic polymers and even combinations of these polymers have demonstrated significant improvement in outcomes of encapsulated grafts. Adequate polymeric surface properties have been shown to be essential but how the surface should be composed to avoid host responses remains to be identified. Current insight is that optimal biocompatible devices can be created which raises optimism that immunoisolating devices can be created that allows for long term survival of encapsulated replenishable insulin-producing cell sources for treatment of Type 1 Diabetes Mellitus.
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Affiliation(s)
- Shuixan Hu
- Division of Medical Biology, Department of Pathology and Medical Biology, Immunoendocrinology, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
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6
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Lee SY, George JH, Nagel DA, Ye H, Kueberuwa G, Seymour LW. Optogenetic control of iPS cell-derived neurons in 2D and 3D culture systems using channelrhodopsin-2 expression driven by the synapsin-1 and calcium-calmodulin kinase II promoters. J Tissue Eng Regen Med 2019; 13:369-384. [PMID: 30550638 PMCID: PMC6492196 DOI: 10.1002/term.2786] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 09/04/2018] [Accepted: 11/30/2018] [Indexed: 01/01/2023]
Abstract
Development of an optogenetically controllable human neural network model in three-dimensional (3D) cultures can provide an investigative system that is more physiologically relevant and better able to mimic aspects of human brain function. Light-sensitive neurons were generated by transducing channelrhodopsin-2 (ChR2) into human induced pluripotent stem cell (hiPSC) derived neural progenitor cells (Axol) using lentiviruses and cell-type specific promoters. A mixed population of human iPSC-derived cortical neurons, astrocytes and progenitor cells were obtained (Axol-ChR2) upon neural differentiation. Pan-neuronal promoter synapsin-1 (SYN1) and excitatory neuron-specific promoter calcium-calmodulin kinase II (CaMKII) were used to drive reporter gene expression in order to assess the differentiation status of the targeted cells. Expression of ChR2 and characterisation of subpopulations in differentiated Axol-ChR2 cells were evaluated using flow cytometry and immunofluorescent staining. These cells were transferred from 2D culture to 3D alginate hydrogel functionalised with arginine-glycine-aspartate (RGD) and small molecules (Y-27632). Improved RGD-alginate hydrogel was physically characterised and assessed for cell viability to serve as a generic 3D culture system for human pluripotent stem cells (hPSCs) and neuronal cells. Prior to cell encapsulation, neural network activities of Axol-ChR2 cells and primary neurons were investigated using calcium imaging. Results demonstrate that functional activities were successfully achieved through expression of ChR2- by both the CaMKII and SYN1 promoters. The RGD-alginate hydrogel system supports the growth of differentiated Axol-ChR2 cells whilst allowing detection of ChR2 expression upon light stimulation. This allows precise and non-invasive control of human neural networks in 3D.
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Affiliation(s)
- Si-Yuen Lee
- Department of Oncology, Old Road Campus Research Building, University of Oxford, Oxford, UK.,Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, UK
| | - Julian H George
- Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, UK
| | - David A Nagel
- School of Life and Health Sciences, University of Aston, Birmingham, UK
| | - Hua Ye
- Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, UK
| | - Gray Kueberuwa
- Department of Cancer Sciences, Manchester Cancer Research Centre, University of Manchester, Manchester, UK
| | - Leonard W Seymour
- Department of Oncology, Old Road Campus Research Building, University of Oxford, Oxford, UK
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Abstract
The promise of pancreatic islet transplantation is hindered by organ shortage, and the need for immunosuppression of transplant recipient in order to prevent rejection. Alginate microencapsulation can overcome these hurdles; however further optimization of this technique is required. Among the critical factors to be optimized is the durability of alginate microcapsules, which can be determined by their mechanical strength tests. Here we describe several simple and reliable methods to assist in assessing the mechanical strength of alginate beads.
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Paredes Juárez GA, Spasojevic M, Faas MM, de Vos P. Immunological and technical considerations in application of alginate-based microencapsulation systems. Front Bioeng Biotechnol 2014; 2:26. [PMID: 25147785 PMCID: PMC4123607 DOI: 10.3389/fbioe.2014.00026] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/17/2014] [Indexed: 01/31/2023] Open
Abstract
Islets encapsulated in immunoprotective microcapsules are being proposed as an alternative for insulin therapy for treatment of type 1 diabetes. Many materials for producing microcapsules have been proposed but only alginate does currently qualify as ready for clinical application. However, many different alginate-based capsule systems do exist. A pitfall in the field is that these systems are applied without a targeted strategy with varying degrees of success as a consequence. In the current review, the different properties of alginate-based systems are reviewed in view of future application in humans. The use of allogeneic and xenogeneic islet sources are discussed with acknowledging the different degrees of immune protection the encapsulation system should supply. Also issues such as oxygen supply and the role of danger associated molecular patterns (DAMPS) in immune activation are being reviewed. A common property of the encapsulation systems is that alginates for medical application should have an extreme high degree of purity and lack pathogen-associated molecular patterns (PAMPs) to avoid activation of the recipient’s immune system. Up to now, non-inflammatory alginates are only produced on a lab-scale and are not yet commercially available. This is a major pitfall on the route to human application. Also the lack of predictive pre-clinical models is a burden. The principle differences between relevant innate and adaptive immune responses in humans and other species are reviewed. Especially, the extreme differences between the immune system of non-human primates and humans are cumbersome as non-human primates may not be predictive of the immune responses in humans, as opposed to the popular belief of regulatory agencies. Current insight is that although the technology is versatile major research efforts are required for identifying the mechanical, immunological, and physico-chemical requirements that alginate-based capsules should meet for successful human application.
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Affiliation(s)
- Genaro Alberto Paredes Juárez
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen , Groningen , Netherlands
| | - Milica Spasojevic
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen , Groningen , Netherlands ; Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen , Groningen , Netherlands
| | - Marijke M Faas
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen , Groningen , Netherlands
| | - Paul de Vos
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen , Groningen , Netherlands
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9
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Workman VL, Tezera LB, Elkington PT, Jayasinghe SN. Controlled Generation of Microspheres Incorporating Extracellular Matrix Fibrils for Three-Dimensional Cell Culture. ADVANCED FUNCTIONAL MATERIALS 2014; 24:2648-2657. [PMID: 25411575 PMCID: PMC4233144 DOI: 10.1002/adfm.201303891] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A growing body of evidence suggests that studying cell biology in classical two-dimensional formats, such as cell culture plasticware, results in misleading, non-physiological findings. For example, some aspects of cancer biology cannot be observed in 2D, but require 3D culture methods to recapitulate observations in vivo. Therefore, we developed a microsphere-based model to permit 3D cell culture incorporating physiological extracellular matrix components. Bio-electrospraying was chosen as it is the most advanced method to produce microspheres, with THP-1 cells as a model cell line. Bio-electrospraying parameters, such as nozzle size, polymer flow rate, and voltage, were systematically optimized to allow stable production of size controlled microspheres containing extracellular matrix material and human cells. We investigated the effect of bio-electrospraying parameters, alginate type and cell concentration on cell viability using trypan blue and propidium iodide staining. Bio-electrospraying had no effect on cell viability nor the ability of cells to proliferate. Cell viability was similarly minimally affected by encapsulation in all types of alginate tested (MVM, MVG, chemical- and food-grade). Cell density of 5 × 106 cells ml-1 within microspheres was the optimum for cell survival and proliferation. The stable generation of microspheres incorporating cells and extracellular matrix for use in a 3D cell culture will benefit study of many diverse diseases and permit investigation of cellular biology within a 3D matrix.
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Affiliation(s)
- Victoria L. Workman
- BioPhysics Group, UCL Institute of Biomedical Engineering, UCL Centre for Stem Cells and Regenerative Medicine and Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, United Kingdom
| | - Liku B. Tezera
- Clinical and Experimental Sciences, Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, United Kingdom
| | - Paul T. Elkington
- Clinical and Experimental Sciences, Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, United Kingdom
| | - Suwan N. Jayasinghe
- BioPhysics Group, UCL Institute of Biomedical Engineering, UCL Centre for Stem Cells and Regenerative Medicine and Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, United Kingdom
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10
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Bidarra SJ, Barrias CC, Granja PL. Injectable alginate hydrogels for cell delivery in tissue engineering. Acta Biomater 2014; 10:1646-62. [PMID: 24334143 DOI: 10.1016/j.actbio.2013.12.006] [Citation(s) in RCA: 339] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 11/28/2013] [Accepted: 12/05/2013] [Indexed: 12/16/2022]
Abstract
Alginate hydrogels are extremely versatile and adaptable biomaterials, with great potential for use in biomedical applications. Their extracellular matrix-like features have been key factors for their choice as vehicles for cell delivery strategies aimed at tissue regeneration. A variety of strategies to decorate them with biofunctional moieties and to modulate their biophysical properties have been developed recently, which further allow their tailoring to the desired application. Additionally, their potential use as injectable materials offers several advantages over preformed scaffold-based approaches, namely: easy incorporation of therapeutic agents, such as cells, under mild conditions; minimally invasive local delivery; and high contourability, which is essential for filling in irregular defects. Alginate hydrogels have already been explored as cell delivery systems to enhance regeneration in different tissues and organs. Here, the in vitro and in vivo potential of injectable alginate hydrogels to deliver cells in a targeted fashion is reviewed. In each example, the selected crosslinking approach, the cell type, the target tissue and the main findings of the study are highlighted.
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Affiliation(s)
- Sílvia J Bidarra
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal.
| | - Cristina C Barrias
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal.
| | - Pedro L Granja
- INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; FEUP - Faculdade de Engenharia da Universidade do Porto, Departamento de Engenharia Metalúrgica e de Materiais, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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11
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Lee BB, Ravindra P, Chan ES. Size and Shape of Calcium Alginate Beads Produced by Extrusion Dripping. Chem Eng Technol 2013. [DOI: 10.1002/ceat.201300230] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Abstract
Islet transplantation has been shown to be a viable treatment option for patients afflicted with type 1 diabetes. However, the lack of availablity of human pancreases and the need to use risky immunosuppressive drugs to prevent transplant rejection remain two major obstacles to the routine use of islet transplantation in diabetic patients. Successful development of a bioartificial pancreas using the approach of microencapsulation with perm-selective coating of islets in hydrogels for graft immunoisolation holds tremendous promise for diabetic patients because it has great potential to overcome these two barriers. In this review article, we will discuss the need for a bioartificial pancreas, provide a detailed description of the microencapsulation process, and review the status of the technology in clinical development. We will also critically review the various factors that will need to be taken into consideration in order to achieve the ultimate goal of routine clinical application.
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Affiliation(s)
- Rajesh A Pareta
- Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Alan C Farney
- Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Emmanuel C Opara
- Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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13
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Moya ML, Morley M, Khanna O, Opara EC, Brey EM. Stability of alginate microbead properties in vitro. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2012; 23:903-912. [PMID: 22350778 PMCID: PMC3810352 DOI: 10.1007/s10856-012-4575-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 01/30/2012] [Indexed: 05/31/2023]
Abstract
Alginate microbeads have been investigated clinically for a number of therapeutic interventions, including drug delivery for treatment of ischemic tissues, cell delivery for tissue regeneration, and islet encapsulation as a therapy for type I diabetes. The physical properties of the microbeads play an important role in regulating cell behavior, protein release, and biological response following implantation. In this research alginate microbeads were synthesized, varying composition (mannuronic acid to guluronic acid ratio), concentration of alginate and needle gauge size. Following synthesis, the size, volume fraction, and morphometry of the beads were quantified. In addition, these properties were monitored over time in vitro in the presence of varying calcium levels in the microenvironment. The initial volume available for solute diffusion increased with alginate concentration and mannuronic (M) acid content, and bead diameter decreased with M content but increased with needle diameter. Interestingly, microbeads eroded completely in saline in less than 3 weeks regardless of synthesis conditions much faster than what has been observed in vivo. However, microbead stability was increased by the addition of calcium in the culture medium. Beads synthesized with low alginate concentration and high G content exhibited a more rapid change in physical properties even in the presence of calcium. These data suggest that temporal variations in the physical characteristics of alginate microbeads can occur in vitro depending on synthesis conditions and microbead environment. The results presented here will assist in optimizing the design of the materials for clinical application in drug delivery and cell therapy.
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Affiliation(s)
- Monica L. Moya
- Pritzker Institute of Biomedical Science & Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA. Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Michael Morley
- Pritzker Institute of Biomedical Science & Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA. Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Omaditya Khanna
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Emmanuel C. Opara
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winton-Salem, NC, USA
| | - Eric M. Brey
- Pritzker Institute of Biomedical Science & Engineering, Illinois Institute of Technology, 3255 South Dearborn St, Chicago, IL 60616, USA. Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA. Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
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14
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Abstract
Alginate is a biomaterial that has found numerous applications in biomedical science and engineering due to its favorable properties, including biocompatibility and ease of gelation. Alginate hydrogels have been particularly attractive in wound healing, drug delivery, and tissue engineering applications to date, as these gels retain structural similarity to the extracellular matrices in tissues and can be manipulated to play several critical roles. This review will provide a comprehensive overview of general properties of alginate and its hydrogels, their biomedical applications, and suggest new perspectives for future studies with these polymers.
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15
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Jeong JH, Hong SW, Hong S, Yook S, Jung Y, Park JB, Khue CD, Im BH, Seo J, Lee H, Ahn CH, Lee DY, Byun Y. Surface camouflage of pancreatic islets using 6-arm-PEG-catechol in combined therapy with tacrolimus and anti-CD154 monoclonal antibody for xenotransplantation. Biomaterials 2011; 32:7961-70. [DOI: 10.1016/j.biomaterials.2011.06.068] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 06/28/2011] [Indexed: 12/11/2022]
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16
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The reversal of diabetes in rat model using mouse insulin producing cells - a combination approach of tissue engineering and macroencapsulation. Acta Biomater 2011; 7:2153-62. [PMID: 21295162 DOI: 10.1016/j.actbio.2011.01.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Revised: 12/16/2010] [Accepted: 01/26/2011] [Indexed: 01/03/2023]
Abstract
Type 1 diabetes is a chronic disorder resulting from the autoimmune destruction of insulin-producing cells, a leading cause of morbidity and mortality all over the world. In this study a tissue engineering approach was compared with a macroencapsulation approach to reverse type 1 diabetes in a rat model, using mouse pancreatic progenitor cell (PPC)-derived islet-like clusters and mouse islets. For the tissue engineering approach the cells were cultured on gelatin scaffolds cross-linked with EDC in the presence of polyvinylpyrrolidone in vitro (GPE scaffolds), while for the macroencapsulation approach the cells were encapsulated in polyurethane-polyvinylpyrrolidone semi-interpenetrating networks. In the combination approach the cells cultured on GPE scaffolds were further encapsulated in a polyurethane-polyvinylpyrrolidone capsule. Real time PCR studies and the glucose challenge assay have shown that cells on GPE scaffolds could express and secrete insulin and glucagon in vitro. However, under in vivo conditions the animals treated by the tissue engineering approach died within 15-20 days and showed no reversal of their diabetes, due to infiltration of immune cells such as CD4 and CD8 cells and macrophages. In the macroencapsulation approach the animals showed euglycemia within 25 days, which was maintained for further 20 days, but after that the animals died. Interestingly, in the combination approach the animals showed reversal of hyperglycemia, and remained euglycemic for up to 3 months. The time needed to achieve initial euglycemia was different with different cell types, i.e. the combination approach with mouse islets achieved euglycemia within 15 days, whereas with PPC-derived islet-like clusters euglycemia was achieved within 25 days. This study confirmed that a combination of tissue engineering and macroencapsulation with mouse islets could reverse diabetes and maintain euglycemia in an experimental diabetes rat model for 90 days.
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Daoud J, Rosenberg L, Tabrizian M. Pancreatic Islet Culture and Preservation Strategies: Advances, Challenges, and Future Outlook. Cell Transplant 2010; 19:1523-35. [DOI: 10.3727/096368910x515872] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Postisolation islet survival is a critical step for achieving successful and efficient islet transplantation. This involves the optimization of islet culture in order to prolong survival and functionality in vitro. Many studies have focused on different strategies to culture pancreatic islets in vitro through manipulation of culture media, surface modified substrates, and the use of various techniques such as encapsulation, embedding, scaffold, and bioreactor culture strategies. This review aims to present and discuss the different methodologies employed to optimize pancreatic islet culture in vitro as well as address their respective advantages and drawbacks.
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Affiliation(s)
- Jamal Daoud
- Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Lawrence Rosenberg
- Department of Surgery, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Maryam Tabrizian
- Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, QC, Canada
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18
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Davis HE, Leach JK. Designing bioactive delivery systems for tissue regeneration. Ann Biomed Eng 2010; 39:1-13. [PMID: 20676773 PMCID: PMC3010216 DOI: 10.1007/s10439-010-0135-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 07/20/2010] [Indexed: 11/29/2022]
Abstract
The direct infusion of macromolecules into defect sites generally does not impart adequate physiological responses. Without the protection of delivery systems, inductive molecules may likely redistribute away from their desired locale and are vulnerable to degradation. In order to achieve efficacy, large doses supplied at interval time periods are necessary, often at great expense and ensuing detrimental side effects. The selection of a delivery system plays an important role in the rate of re-growth and functionality of regenerating tissue: not only do the release kinetics of inductive molecules and their consequent bioactivities need to be considered, but also how the delivery system interacts and integrates with its surrounding host environment. In the current review, we describe the means of release of macromolecules from hydrogels, polymeric microspheres, and porous scaffolds along with the selection and utilization of bioactive delivery systems in a variety of tissue-engineering strategies.
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Affiliation(s)
- Hillary E Davis
- Department of Biomedical Engineering, University of California, Davis, 451 Health Sciences Drive, 2303 Genome and Biomedical Sciences Facility, Davis, CA, 95616, USA
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19
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Bratlie KM, Dang TT, Lyle S, Nahrendorf M, Weissleder R, Langer R, Anderson DG. Rapid biocompatibility analysis of materials via in vivo fluorescence imaging of mouse models. PLoS One 2010; 5:e10032. [PMID: 20386609 PMCID: PMC2850367 DOI: 10.1371/journal.pone.0010032] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 03/08/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Many materials are unsuitable for medical use because of poor biocompatibility. Recently, advances in the high throughput synthesis of biomaterials has significantly increased the number of potential biomaterials, however current biocompatibility analysis methods are slow and require histological analysis. METHODOLOGY/PRINCIPAL FINDINGS Here we develop rapid, non-invasive methods for in vivo quantification of the inflammatory response to implanted biomaterials. Materials were placed subcutaneously in an array format and monitored for host responses as per ISO 10993-6: 2001. Host cell activity in response to these materials was imaged kinetically, in vivo using fluorescent whole animal imaging. Data captured using whole animal imaging displayed similar temporal trends in cellular recruitment of phagocytes to the biomaterials compared to histological analysis. CONCLUSIONS/SIGNIFICANCE Histological analysis similarity validates this technique as a novel, rapid approach for screening biocompatibility of implanted materials. Through this technique there exists the possibility to rapidly screen large libraries of polymers in vivo.
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Affiliation(s)
- Kaitlin M. Bratlie
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Anesthesiology, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Tram T. Dang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Anesthesiology, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Stephen Lyle
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Matthias Nahrendorf
- Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Ralph Weissleder
- Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Anesthesiology, Children's Hospital Boston, Boston, Massachusetts, United States of America
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Daniel G. Anderson
- Department of Anesthesiology, Children's Hospital Boston, Boston, Massachusetts, United States of America
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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20
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Chan ES, Lee BB, Ravindra P, Poncelet D. Prediction models for shape and size of ca-alginate macrobeads produced through extrusion–dripping method. J Colloid Interface Sci 2009; 338:63-72. [DOI: 10.1016/j.jcis.2009.05.027] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2009] [Revised: 05/11/2009] [Accepted: 05/11/2009] [Indexed: 11/29/2022]
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21
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Fort A, Fort N, Ricordi C, Stabler CL. Biohybrid devices and encapsulation technologies for engineering a bioartificial pancreas. Cell Transplant 2009; 17:997-1003. [PMID: 19177836 DOI: 10.3727/096368908786991498] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The use of cell-based treatments in the field of metabolic organs, particularly the pancreas, has seen tremendous growth in recent years. The transplantation of islet of Langerhans cells for the treatment of type 1 diabetes mellitus (T1DM) has allowed for natural glycemic control for patients plagued with hypoglycemia unawareness. The transplantation of islet cells into the portal vein of the liver, however, has presented challenges to the survival of the cells due to inflammation, vascularization, the need for systemic immunosuppression, and physical stress on the graft. New advances in the engineering of appropriate biohybrid devices and encapsulation technologies have led to promising alternatives to traditional methods.
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Affiliation(s)
- Alexander Fort
- Diabetes Research Institute, University of Miami, Miami, FL 33136, USA
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22
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A novel macroencapsulating immunoisolatory device: the preparation and properties of nanomat-reinforced amphiphilic co-networks deposited on perforated metal scaffold. Biomed Microdevices 2009; 11:297-312. [PMID: 18987977 DOI: 10.1007/s10544-008-9236-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This paper describes the design and preparation of the non-biological components (the "hardware") of a conceptually novel bioartificial pancreas (BAP) to correct diabetes. The key components of the hardware are (1) a thin (5-10 microm) semipermeable amphiphilic co-network (APCN) membrane [i.e., a membrane of cocontinuous poly(dimethyl acryl amide) (PDMAAm)/polydimethylsiloxane (PDMS) domains cross-linked by polymethylhydrosiloxane (PMHS)] expressly created for macroencapsulation and immunoisolation of a tissue graft; (2) an electrospun nanomat of PDMS-containing polyurethane to reinforce the water-swollen APCN membrane; and (3) a perforated hollow-ribbon nitinol scaffold to stiffen and provide geometric stability to the construct. The reinforcement of water-swollen hydrogels with an electrospun nanomat is a generally applicable new method for hydrogel reinforcement. Details of device design and preparation are discussed. The advantages and disadvantages of micro- and macro-immunoisolation are analyzed, and the requirements for the ideal immunoisolatory membrane are presented. Burst pressure, and glucose and insulin permeabilities of representative devices have been determined and the effect of device composition and wall thickness on these properties is discussed.
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23
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Darrabie MD, Kendall WF, Opara EC. Effect of alginate composition and gelling cation on micro-bead swelling. J Microencapsul 2008; 23:29-37. [PMID: 16830975 DOI: 10.1080/02652040500286144] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE The purpose of this study was to determine the roles of alginate composition and gelling cations on bead swelling, which affects its durability. METHOD Using a 2-channel droplet generator, microspheres were generated with 1.5% solutions of low viscosity high-mannuronic acid (LVM), medium viscosity high-mannuronic acid (MVM), low viscosity high-guluronic acid (LVG) and medium viscosity high-guluronic acid (MVG) alginate. They were gelled by cross-linking with 1.1% solution of either BaCl2 or CaCl2. The diameters of the micro-beads were measured and recorded on day 0. The micro-beads were subsequently washed and incubated in saline at 37 degrees C for 2 weeks with size assessment every 2 days. The data were normalized by calculation of the percentage change from control (day 0) for all groups of micro-beads. RESULTS Diameters of all beads were between 550 and 700 microm on day 0. Viscosity had no effect on swelling of Ba++- and Ca++-alginate micro-beads. Ca++-alginate micro-beads were more prone to swelling than the corresponding Ba++-alginate beads. High G-Ba++ beads had only a modest increase in size over time, in contrast to the high M-Ba++. CONCLUSION Alginate composition and the gelling cation have significant effects on bead swelling.
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Affiliation(s)
- Marcus D Darrabie
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
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24
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Darrabie MD, Kendall WF, Opara EC. Effect of alginate composition and gelling cation on microbead swelling. J Microencapsul 2008; 23:613-21. [PMID: 17118877 DOI: 10.1080/02652040600687621] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE The purpose of this study was to determine the roles of alginate composition and gelling cations on bead swelling, which affects its durability. METHOD Using a 2-channel droplet generator, microspheres were generated with 1.5% solutions of low viscosity high-mannuronic acid (LVM), medium viscosity high-mannuronic acid (MVM), low viscosity high-guluronic acid (LVG) and medium viscosity high-guluronic acid (MVG) alginate. They were gelled by cross-linking with 1.1% solution of either BaCl2 or CaCl2. The diameters of the microbeads were measured and recorded on day 0. The microbeads were subsequently washed and incubated in saline at 37 degrees C for 2 weeks with size assessment every 2 days. The data were normalized by calculation of the percentage change from control (day 0) for all groups of microbeads. RESULTS Diameters of all beads were between 550-700 microns on day 0. Viscosity had no effect on swelling of Ba++- and Ca++-alginate microbeads. Ca++-alginate microbeads were more prone to swelling than the corresponding Ba++-alginate beads. High G-Ba++ beads had only a modest increase in size over time, in contrast to the high M-Ba++. CONCLUSION Alginate composition and the gelling cation have significant effects on bead swelling.
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Affiliation(s)
- Marcus D Darrabie
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
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Wee YM, Lim DG, Kim YH, Kim JH, Kim SC, Yu E, Park MO, Choi MY, Park YH, Jang HJ, Cho EY, Cho MH, Han DJ. Cell Surface Modification by Activated Polyethylene Glycol Prevents Allosensitization after Islet Transplantation. Cell Transplant 2008; 17:1257-69. [DOI: 10.3727/096368908787236657] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The necessity to transplant islet tissue without the need for immunosuppressant therapy has led to the development of materials for immune modulation. Pegylation makes islets antigenically silent, protecting them from the adsorption of foreign protein and thus avoiding immune injury. The aim of this study is to determine whether pegylation of islets prolongs islet survival and function both during tissue culture and posttransplantation. We used cyanuric chloride-activated methoxy-polyethylene glycol for cell surface modification. To detect the pegylation effect on splenocytes, we measured antibody binding inhibition and abrogation of lymphocyte proliferation. To detect the pegylation effect on islet grafts, we performed rodent islet transplantation. Islet viability and function were maintained after pegylation. Pegylated islets showed a 90% decrease in antibody binding and decreased lymphocyte proliferation in a mixed lymphocyte culture. However, when pegylated islets were transplanted, no prolongation of graft survival was observed. When a subtherapeutic dose of immunosuppressant was given at the time of transplantation of pegylated islets, islet graft survival was significantly prolonged. In addition, when rats were sensitized with donor splenocytes, graft survival was prolonged by pegylation. We observed that pegylation of islets, combined with a subtherapeutic dose of immunosuppressant, protects the graft from rejection. Prolonged graft survival in sensitized recipients showed that pegylation of islets shifted the pattern of rejection from an acute humoral response to a less aggressive cellular alloresponse.
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Affiliation(s)
- Yu-Mee Wee
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Dong-Gyun Lim
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Yang-Hee Kim
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Jin-Hee Kim
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Song-Cheol Kim
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Eunsil Yu
- Department of Pathology, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | | | - Monica Young Choi
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Youn-Hee Park
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Hyuk-Jai Jang
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Eun-Young Cho
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
| | - Myung-Hwan Cho
- Department of Biological Science, Konkuk University, Seoul, 143-701, Korea
| | - Duck-Jong Han
- Department of Surgery, Ulsan University College of Medicine & Asan Medical Center, Seoul, 138-736, Korea
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Beck J, Angus R, Madsen B, Britt D, Vernon B, Nguyen KT. Islet encapsulation: strategies to enhance islet cell functions. ACTA ACUST UNITED AC 2007; 13:589-99. [PMID: 17518605 DOI: 10.1089/ten.2006.0183] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Although traditional insulin therapy has alleviated the short-term effects, long-term complications are ubiquitous and harmful. For these reasons, alternative treatment options are being developed. This review investigates one appealing area: cell replacement using encapsulated islets. Encapsulation materials, encapsulation methods, and cell sources are presented and discussed. In addition, the major factors that currently limit cell viability and functionality are reviewed, and strategies to overcome these limitations are examined. This review is designed to introduce the reader to cell replacement therapy and cell and tissue encapsulation, especially as it applies to diabetes.
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Affiliation(s)
- Jonathan Beck
- Department of Biological and Irrigation Engineering, Utah State University, Logan, Utah, USA
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