1
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Ajima K, Tsuda N, Takaki T, Furusako S, Matsumoto S, Shinohara K, Yamashita Y, Amano S, Oyama C, Shimoda M. A porcine islet-encapsulation device that enables long-term discordant xenotransplantation in immunocompetent diabetic mice. CELL REPORTS METHODS 2023; 3:100370. [PMID: 36814843 PMCID: PMC9939365 DOI: 10.1016/j.crmeth.2022.100370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/29/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
Islet transplantation is an effective treatment for type 1 diabetes (T1D). However, a shortage of donors and the need for immunosuppressants are major issues. The ideal solution is to develop a source of insulin-secreting cells and an immunoprotective method. No bioartificial pancreas (BAP) devices currently meet all of the functions of long-term glycemic control, islet survival, immunoprotection, discordant xenotransplantation feasibility, and biocompatibility. We developed a device in which porcine islets were encapsulated in a highly stable and permeable hydrogel and a biocompatible immunoisolation membrane. Discordant xenotransplantation of the device into diabetic mice improved glycemic control for more than 200 days. Glycemic control was also improved in new diabetic mice "relay-transplanted" with the device after its retrieval. The easily retrieved devices exhibited almost no adhesion or fibrosis and showed sustained insulin secretion even after the two xenotransplantations. This device has the potential to be a useful BAP for T1D.
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Affiliation(s)
- Kumiko Ajima
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
| | - Naoto Tsuda
- Biomaterials Business Division, Mochida Pharmaceutical Co., Ltd., 722 Uenohara, Jimba, Gotemba, Shizuoka 412-8524, Japan
| | - Tadashi Takaki
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Takeda-CiRA Joint Program (T-CiRA), 2-26-1 Muraoka-higashi, Fujisawa-shi, Kanagawa 251-8555, Japan
| | - Shoji Furusako
- Biomaterials Business Division, Mochida Pharmaceutical Co., Ltd., 1-7 Yotsuya, Shinjuku-ku, Tokyo 160-8515, Japan
| | - Shigeki Matsumoto
- Biomaterials Business Division, Mochida Pharmaceutical Co., Ltd., 722 Uenohara, Jimba, Gotemba, Shizuoka 412-8524, Japan
| | - Koya Shinohara
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
| | - Yzumi Yamashita
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
| | - Sayaka Amano
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
| | - Chinatsu Oyama
- Communal Laboratory, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Masayuki Shimoda
- Pancreatic Islet Cell Transplantation Project, Research Institute National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
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2
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Kumar N, Maher N, Amin F, Ghabbani H, Zafar MS, Rodríguez-Lozano FJ, Oñate-Sánchez RE. Biomimetic Approaches in Clinical Endodontics. Biomimetics (Basel) 2022; 7:biomimetics7040229. [PMID: 36546929 PMCID: PMC9775094 DOI: 10.3390/biomimetics7040229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/19/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.
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Affiliation(s)
- Naresh Kumar
- Department of Science of Dental Materials, Dr. Ishrat Ul Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi 74200, Pakistan
- Correspondence: ; Tel.: +92-333-2818500
| | - Nazrah Maher
- Department of Science of Dental Materials, Dr. Ishrat Ul Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Faiza Amin
- Department of Science of Dental Materials, Dow Dental College, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Hani Ghabbani
- Department of Restorative Dentistry, College of Dentistry, Taibah University, Al Madinah, Al Munawwarah 41311, Saudi Arabia
| | - Muhammad Sohail Zafar
- Department of Restorative Dentistry, College of Dentistry, Taibah University, Al Madinah, Al Munawwarah 41311, Saudi Arabia
- Department of Dental Materials, Islamic International Dental College, Riphah International University, Islamabad 44000, Pakistan
| | | | - Ricardo E. Oñate-Sánchez
- Department of Special Care in Dentistry, Hospital Morales Meseguer, IMIB-Arrixaca, University of Murcia, 30008 Murcia, Spain
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3
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Peng Y, Wang J, Dai X, Chen M, Bao Z, Yang X, Xie J, Wang C, Shao J, Han H, Yao K, Gou Z, Ye J. Precisely Tuning the Pore-Wall Surface Composition of Bioceramic Scaffolds Facilitates Angiogenesis and Orbital Bone Defect Repair. ACS APPLIED MATERIALS & INTERFACES 2022; 14:43987-44001. [PMID: 36102779 DOI: 10.1021/acsami.2c14909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Orbital bone damage (OBD) may result in severe post-traumatic enophthalmos, craniomaxillofacial deformities, vision loss, and intracranial infections. However, it is still a challenge to fabricate advanced biomaterials that can match the individual anatomical structure and enhance OBD repair in situ. Herein, we aimed to develop a selective surface modification strategy on bioceramic scaffolds and evaluated the effects of inorganic or organic functional coating on angiogenesis and osteogenesis, ectopically and orthotopically in OBD models. It was shown that the low thermal bioactive glass (BG) modification or layer-by-layer assembly of a biomimetic hydrogel (Biogel) could readily integrate into the pore wall of the bioceramic scaffolds. The BG and Biogel modification showed appreciable enhancement in the initial compressive strength (∼30-75%) or structural stability in vivo, respectively. BG modification could enhance by nearly 2-fold the vessel ingrowth, and the osteogenic capacity was also accelerated, accompanied with a mild scaffold biodegradation after 3 months. Meanwhile, the Biogel-modified scaffolds showed enhanced osteogenic differentiation and mineralization through calcium and phosphorus retention. The potential mechanism of the enhanced bone repair was elucidated via vascular and osteogenic cell responses in vitro, and the cell tests indicated that the Biogel and BG functional layers were both beneficial for in vitro osteoblastic differentiation and mineralization on bioceramics. Totally, these findings demonstrated that the bioactive ions or biomolecules could significantly improve the angiogenic and osteogenic capabilities of conventional bioceramics, and the integration of inorganic or organic functional coating in the pore wall is a highly flexible material toolbox that can be tailored directly to improve orbital bone defect repair.
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Affiliation(s)
- Yiyu Peng
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Jingyi Wang
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Xizhe Dai
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Menglu Chen
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Zhaonan Bao
- Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China
| | - Xianyan Yang
- Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China
| | - Jiajun Xie
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Changjun Wang
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Ji Shao
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Haijie Han
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Ke Yao
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Zhongru Gou
- Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China
| | - Juan Ye
- Eye Center, Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
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4
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Encapsulation Strategies for Pancreatic Islet Transplantation without Immune Suppression. CURRENT STEM CELL REPORTS 2021. [DOI: 10.1007/s40778-021-00190-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Kuwabara R, Hu S, Smink AM, Orive G, Lakey JRT, de Vos P. Applying Immunomodulation to Promote Longevity of Immunoisolated Pancreatic Islet Grafts. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:129-140. [PMID: 33397201 DOI: 10.1089/ten.teb.2020.0326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Islet transplantation is a promising therapy for insulin-dependent diabetes, but large-scale application is hampered by the lack of a consistent source of insulin-producing cells and need for lifelong administration of immunosuppressive drugs, which are associated with severe side effects. To avoid chronic immunosuppression, islet grafts can be enveloped in immunoisolating polymeric membranes. These immunoisolating polymeric membranes protect islet grafts from cell-mediated rejection while allowing diffusion of oxygen, nutrients, and insulin. Although clinical trials have shown the safety and feasibility of encapsulated islets to control glucose homeostasis, the strategy does up till now not support long-term graft survival. This partly can be explained by a significant loss of insulin-producing cells in the immediate period after implantation. The loss can be prevented by combining immunoisolation with immunomodulation, such as combined administration of immunomodulating cytokines or coencapsulation of immunomodulating cell types such as regulatory T cells, mesenchymal stem cells, or Sertoli cells. Also, administration of specific antibodies or apoptotic donor leucocytes is considered to create a tolerant microenvironment around immunoisolated grafts. In this review, we describe the outcomes and limitations of these approaches, as well as the recent progress in immunoisolating devices. Impact statement Immunoisolation by enveloping islets in semipermeable membranes allows for successful transplantation of islet grafts in the absence of chronic immunosuppression, but the duration of graft survival is still not permanent. The reasons for long-term final graft failure is not fully understood, but combining immunoisolation with immunomodulation of tissues or host immune system has been proposed to enhance the longevity of grafts. This article reviews the recent progress and challenges of immunoisolation, as well as the benefits and feasibility of combining encapsulation approaches with immunomodulation to promote longevity of encapsulated grafts.
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Affiliation(s)
- Rei Kuwabara
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Biomaterials, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shuxian Hu
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Alexandra M Smink
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gorka Orive
- NanoBioCel Group, Laboratory of Pharmaceutics, School of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Jonathan R T Lakey
- Department of Surgery and Biomedical Engineering, University of California Irvine, Irvine, California, USA
| | - Paul de Vos
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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6
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Tan RP, Hallahan N, Kosobrodova E, Michael PL, Wei F, Santos M, Lam YT, Chan AHP, Xiao Y, Bilek MMM, Thorn P, Wise SG. Bioactivation of Encapsulation Membranes Reduces Fibrosis and Enhances Cell Survival. ACS APPLIED MATERIALS & INTERFACES 2020; 12:56908-56923. [PMID: 33314916 DOI: 10.1021/acsami.0c20096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Encapsulation devices are an emerging barrier technology designed to prevent the immunorejection of replacement cells in regenerative therapies for intractable diseases. However, traditional polymers used in current devices are poor substrates for cell attachment and induce fibrosis upon implantation, impacting long-term therapeutic cell viability. Bioactivation of polymer surfaces improves local host responses to materials, and here we make the first step toward demonstrating the utility of this approach to improve cell survival within encapsulation implants. Using therapeutic islet cells as an exemplar cell therapy, we show that internal surface coatings improve islet cell attachment and viability, while distinct external coatings modulate local foreign body responses. Using plasma surface functionalization (plasma immersion ion implantation (PIII)), we employ hollow fiber semiporous poly(ether sulfone) (PES) encapsulation membranes and coat the internal surfaces with the extracellular matrix protein fibronectin (FN) to enhance islet cell attachment. Separately, the external fiber surface is coated with the anti-inflammatory cytokine interleukin-4 (IL-4) to polarize local macrophages to an M2 (anti-inflammatory) phenotype, muting the fibrotic response. To demonstrate the power of our approach, bioluminescent murine islet cells were loaded into dual FN/IL-4-coated fibers and evaluated in a mouse back model for 14 days. Dual FN/IL-4 fibers showed striking reductions in immune cell accumulation and elevated levels of the M2 macrophage phenotype, consistent with the suppression of fibrotic encapsulation and enhanced angiogenesis. These changes led to markedly enhanced islet cell survival and importantly to functional integration of the implant with the host vasculature. Dual FN/IL-4 surface coatings drive multifaceted improvements in islet cell survival and function, with significant implications for improving clinical translation of therapeutic cell-containing macroencapsulation implants.
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Affiliation(s)
- Richard P Tan
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Nicole Hallahan
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Elena Kosobrodova
- Applied Plasma and Physics, A28, School of Physics, University of Sydney, Physics Road, Camperdown, NSW 2006, Australia
| | - Praveesuda L Michael
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Fei Wei
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, QLD 4000, Australia
| | - Miguel Santos
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Yuen Ting Lam
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Alex H P Chan
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305, United States
| | - Yin Xiao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, QLD 4000, Australia
| | - Marcela M M Bilek
- Applied Plasma and Physics, A28, School of Physics, University of Sydney, Physics Road, Camperdown, NSW 2006, Australia
| | - Peter Thorn
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
| | - Steven G Wise
- Department of Physiology, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Charles Perkins Centre, University of Sydney, John Hopkins Drive, Camperdown, NSW 2006, Australia
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7
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Skrzypek K, Groot Nibbelink M, Liefers-Visser J, Smink AM, Stoimenou E, Engelse MA, de Koning EJP, Karperien M, de Vos P, van Apeldoorn A, Stamatialis D. A High Cell-Bearing Capacity Multibore Hollow Fiber Device for Macroencapsulation of Islets of Langerhans. Macromol Biosci 2020; 20:e2000021. [PMID: 32567161 DOI: 10.1002/mabi.202000021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 06/02/2020] [Indexed: 01/03/2023]
Abstract
Macroencapsulation of islets of Langerhans is a promising strategy for transplantation of insulin-producing cells in the absence of immunosuppression to treat type 1 diabetes. Hollow fiber membranes are of interest there because they offer a large surface-to-volume ratio and can potentially be retrieved or refilled. However, current available fibers have limitations in exchange of nutrients, oxygen, and delivery of insulin potentially impacting graft survival. Here, multibore hollow fibers for islets encapsulation are designed and tested. They consist of seven bores and are prepared using nondegradable polymers with high mechanical stability and low cell adhesion properties. Human islets encapsulated there have a glucose induced insulin response (GIIS) similar to nonencapsulated islets. During 7 d of cell culture in vitro, the GIIS increases with graded doses of islets demonstrating the suitability of the microenvironment for islet survival. Moreover, first implantation studies in mice demonstrate device material biocompatibility with minimal tissue responses. Besides, formation of new blood vessels close to the implanted device is observed, an important requirement for maintaining islet viability and fast exchange of glucose and insulin. The results indicate that the developed fibers have high islet bearing capacity and can potentially be applied for a clinically applicable bioartificial pancreas.
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Affiliation(s)
- Katarzyna Skrzypek
- Bioartificial Organs, Biomaterials Science and Technology Department, Faculty of Science and Technology, TechMed Centre, University of Twente, Enschede, 7500AE, The Netherlands
| | - Milou Groot Nibbelink
- Developmental BioEngineering, Faculty of Science and Technology, TechMed Centre, University of Twente, Enschede, 7500AE, The Netherlands
| | - Jolanda Liefers-Visser
- Pathology and Medical Biology, Section Immunoendocrinology, University of Groningen, University Medical Center Groningen, Groningen, 9713GZ, The Netherlands
| | - Alexandra M Smink
- Pathology and Medical Biology, Section Immunoendocrinology, University of Groningen, University Medical Center Groningen, Groningen, 9713GZ, The Netherlands
| | - Eleftheria Stoimenou
- Faculty of Sciences, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
| | - Marten A Engelse
- Nephrology, Leiden University Medical Center, Leiden, 2333ZA, The Netherlands
| | - Eelco J P de Koning
- Nephrology, Leiden University Medical Center, Leiden, 2333ZA, The Netherlands.,Hubrecht Institute, Utrecht, 3584CT, The Netherlands
| | - Marcel Karperien
- Developmental BioEngineering, Faculty of Science and Technology, TechMed Centre, University of Twente, Enschede, 7500AE, The Netherlands
| | - Paul de Vos
- Pathology and Medical Biology, Section Immunoendocrinology, University of Groningen, University Medical Center Groningen, Groningen, 9713GZ, The Netherlands
| | - Aart van Apeldoorn
- Complex Tissue Regeneration, MERLN Institute for Technology Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
| | - Dimitrios Stamatialis
- Bioartificial Organs, Biomaterials Science and Technology Department, Faculty of Science and Technology, TechMed Centre, University of Twente, Enschede, 7500AE, The Netherlands
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8
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Smink AM, de Haan BJ, Lakey JRT, de Vos P. Polymer scaffolds for pancreatic islet transplantation - Progress and challenges. Am J Transplant 2018; 18:2113-2119. [PMID: 29790274 DOI: 10.1111/ajt.14942] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/18/2018] [Accepted: 05/10/2018] [Indexed: 02/06/2023]
Abstract
Pancreatic-islet transplantation is a safe and noninvasive therapy for type 1 diabetes. However, the currently applied site for transplantation, ie, the liver, is not the optimal site for islet survival. Because the human body has shortcomings in providing an optimal site, artificial transplantation sites have been proposed. Such an artificial site could consist of a polymeric scaffold that mimics the pancreatic microenvironment and supports islet function. Recently, remarkable progress has been made in the technology of engineering scaffolds. The polymer-islet interactions, the site of implantation, and scaffold prevascularization are critical factors for success or failure of the scaffolds. This article critically reviews these factors while also discussing translation of experimental studies to human application as well as the steps required to create a clinically applicable prevascularized, retrievable scaffold for implantation of insulin-producing cells for treatment of type 1 diabetes mellitus.
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Affiliation(s)
- Alexandra M Smink
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Bart J de Haan
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jonathan R T Lakey
- Department of Surgery, University of California Irvine, Orange, CA, USA.,Department of Biomedical Engineering, University of California Irvine, Irvine, CA, USA
| | - Paul de Vos
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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9
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Yang KC, Yanai G, Yang SY, Canning P, Satou Y, Kawagoe M, Sumi S. Low-adhesive ethylene vinyl alcohol-based packaging to xenogeneic islet encapsulation for type 1 diabetes treatment. Biotechnol Bioeng 2018; 115:2341-2355. [PMID: 29777589 DOI: 10.1002/bit.26730] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/17/2018] [Accepted: 05/16/2018] [Indexed: 01/16/2023]
Abstract
Transplantation of encapsulated porcine islets is proposed to treat type 1 diabetes. However, the envelopment of fibrous tissue and the infiltration of immune cells impair islet function and eventually cause implant failure. It is known that hemodialysis using an ethylene vinyl alcohol (EVOH) membrane results in minor tissue responses. Therefore, we hypothesized that using a low-adhesive EVOH membrane for encapsulation may prevent host cell accumulation and fibrous capsule formation. In this study, rat islets suspended in chitosan gel were encapsulated in bags made from highly porous EVOH membranes, and their in vitro insulin secretion function as well as in vivo performance was evaluated. The results showed that the EVOH bag did not affect islet survival or glucose-stimulated insulin secretion. Whereas naked islets were dysfunctional after 7 days of culture in vitro, islets within the EVOH bag produced insulin continuously for 30 days. Streptozotocin-induced diabetic mice were given islets-chitosan gel-EVOH implants intraperitoneally (650-800 islets equivalent) and exhibited lower blood glucose levels and regained body weight during a 4-week observation period. The transplanted mice had higher levels of serum insulin and C-peptide, with an improved blood glucose disappearance rate. Retrieved implants had minor tissue adhesion, and histology showed a limited number of mononuclear cells and fibroblasts surrounding the implants. No invasion of host cells into the EVOH bags was noticed, and the encapsulated islets were intact and positive for insulin-glucagon immunostaining. In conclusion, an EVOH bag can protect encapsulated islets, limit fibrous capsule formation, and extend graft function.
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Affiliation(s)
- Kai-Chiang Yang
- Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Goichi Yanai
- Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Sin-Yu Yang
- Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Priyadarshini Canning
- Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshio Satou
- Molding Component Business Department, Kuraray Co., Ltd, Tokyo, Japan
| | - Masako Kawagoe
- Molding Component Business Department, Kuraray Co., Ltd, Tokyo, Japan
| | - Shoichiro Sumi
- Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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10
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Lee EM, Jung JI, Alam Z, Yi HG, Kim H, Choi JW, Hurh S, Kim YJ, Jeong JC, Yang J, Oh KH, Kim HC, Lee BC, Choi I, Cho DW, Ahn C. Effect of an oxygen-generating scaffold on the viability and insulin secretion function of porcine neonatal pancreatic cell clusters. Xenotransplantation 2018; 25:e12378. [DOI: 10.1111/xen.12378] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/15/2017] [Accepted: 11/24/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Eun Mi Lee
- Graduate School of Translational Medicine; Seoul National University College of Medicine; Seoul Korea
- Center for Medical Innovation; Biomedical Research Institute; Seoul National University Hospital; Seoul Korea
| | - Ji-In Jung
- Department of Mechanical Engineering; Pohang University of Science and Technology (POSTECH); Pohang Gyeongsangbuk-do Korea
| | - Zahid Alam
- Center for Medical Innovation; Biomedical Research Institute; Seoul National University Hospital; Seoul Korea
| | - Hee-Gyeong Yi
- Department of Mechanical Engineering; Pohang University of Science and Technology (POSTECH); Pohang Gyeongsangbuk-do Korea
| | - Heejin Kim
- Interdisciplinary Program in Bioengineering; Graduate School; Seoul National University; Seoul Korea
| | - Jin Woo Choi
- Interdisciplinary Program in Bioengineering; Graduate School; Seoul National University; Seoul Korea
| | - Sunghoon Hurh
- Center for Medical Innovation; Biomedical Research Institute; Seoul National University Hospital; Seoul Korea
| | - Young June Kim
- Designed Animal & Transplantation Research Institute; Institute of Green Bio Science & Technology; Seoul National University; Pyeongchang Gangwon-do Korea
| | - Jong Cheol Jeong
- Department of Nephrology; Ajou University School of Medicine; Suwon Gyeonggi-do Korea
| | - Jaeseok Yang
- Transplantation Center; Seoul National University Hospital; Seoul Korea
- Department of Surgery; Seoul National University Hospital; Seoul Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine; Seoul National University College of Medicine; Seoul Korea
| | - Hee Chan Kim
- Department of Biomedical Engineering; Seoul National University College of Medicine; Seoul Korea
| | - Byeong Chun Lee
- Designed Animal & Transplantation Research Institute; Institute of Green Bio Science & Technology; Seoul National University; Pyeongchang Gangwon-do Korea
- Department of Theriogenology and Biotechnology; College of Veterinary Medicine; Seoul National University; Seoul Korea
| | - Inho Choi
- Department of Pharmaceutical Engineering; College of Life and Health Sciences; Hoseo University; Asan Chungcheongnam-do Korea
| | - Dong-Woo Cho
- Department of Mechanical Engineering; Pohang University of Science and Technology (POSTECH); Pohang Gyeongsangbuk-do Korea
| | - Curie Ahn
- Designed Animal & Transplantation Research Institute; Institute of Green Bio Science & Technology; Seoul National University; Pyeongchang Gangwon-do Korea
- Department of Internal Medicine; Seoul National University College of Medicine; Seoul Korea
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11
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Buchwald P, Tamayo-Garcia A, Manzoli V, Tomei AA, Stabler CL. Glucose-stimulated insulin release: Parallel perifusion studies of free and hydrogel encapsulated human pancreatic islets. Biotechnol Bioeng 2018; 115:232-245. [PMID: 28865118 PMCID: PMC5699962 DOI: 10.1002/bit.26442] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/14/2017] [Accepted: 08/30/2017] [Indexed: 12/29/2022]
Abstract
To explore the effects immune-isolating encapsulation has on the insulin secretion of pancreatic islets and to improve our ability to quantitatively describe the glucose-stimulated insulin release (GSIR) of pancreatic islets, we conducted dynamic perifusion experiments with isolated human islets. Free (unencapsulated) and hydrogel encapsulated islets were perifused, in parallel, using an automated multi-channel system that allows sample collection with high temporal resolution. Results indicated that free human islets secrete less insulin per unit mass or islet equivalent (IEQ) than murine islets and with a less pronounced first-phase peak. While small microcapsules (d = 700 µm) caused only a slightly delayed and blunted first-phase insulin response compared to unencapsulated islets, larger capsules (d = 1,800 µm) completely blunted the first-phase peak and decreased the total amount of insulin released. Experimentally obtained insulin time-profiles were fitted with our complex insulin secretion computational model. This allowed further fine-tuning of the hormone-release parameters of this model, which was implemented in COMSOL Multiphysics to couple hormone secretion and nutrient consumption kinetics with diffusive and convective transport. The results of these GSIR experiments, which were also supported by computational modeling, indicate that larger capsules unavoidably lead to dampening of the first-phase insulin response and to a sustained-release type insulin secretion that can only slowly respond to changes in glucose concentration. Bioartificial pancreas type devices can provide long-term and physiologically desirable solutions only if immunoisolation and biocompatibility considerations are integrated with optimized nutrient diffusion and insulin release characteristics by design.
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Affiliation(s)
- Peter Buchwald
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, FL
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL
| | | | - Vita Manzoli
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, FL
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Alice A. Tomei
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, FL
- Biomedical Engineering, University of Miami, Miller School of Medicine, Miami, FL
| | - Cherie L. Stabler
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
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Lee SJ, Lee JB, Park YW, Lee DY. 3D Bioprinting for Artificial Pancreas Organ. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1064:355-374. [PMID: 30471043 DOI: 10.1007/978-981-13-0445-3_21] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Type 1 diabetes mellitus (T1DM) results from an autoimmune destruction of insulin-producing beta cells in the islet of the endocrine pancreas. Although islet transplantation has been regarded as an ideal strategy for T1D, transplanted islets are rejected from host immune system. To immunologically protect them, islet encapsulation technology with biocompatible materials is emerged as an immuno-barrier. However, this technology has been limited for clinical trial such as hypoxia in the central core of islet bead, impurity of islet bead and retrievability from the body. Recently, 3D bioprinting has been emerged as an alternative approach to make the artificial pancreas. It can be used to position live cells in a desired location with real scale of human organ. Furthermore, constructing a vascularization of the artificial pancreas is actualized with 3D bioprinting. Therefore, it is possible to create real pancreas-mimic artificial organ for clinical application. In conclusion, 3D bioprinting can become a new leader in the development of the artificial pancreas to overcome the existed islet.
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Affiliation(s)
- Seon Jae Lee
- Department of Bioengineering, College of Engineering, BK21 PLUS Future Biopharmaceutical Human Resource Training and Research Team, Hanyang University, Seoul, South Korea
| | - Jae Bin Lee
- Department of Bioengineering, College of Engineering, BK21 PLUS Future Biopharmaceutical Human Resource Training and Research Team, Hanyang University, Seoul, South Korea
| | - Young-Woo Park
- Department of Bioengineering, College of Engineering, BK21 PLUS Future Biopharmaceutical Human Resource Training and Research Team, Hanyang University, Seoul, South Korea
| | - Dong Yun Lee
- Department of Bioengineering, College of Engineering, BK21 PLUS Future Biopharmaceutical Human Resource Training and Research Team, Hanyang University, Seoul, South Korea. .,Institute of Nano Science & Technology (INST), Hanyang University, Seoul, South Korea.
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Weber LM, Cheung CY, Anseth KS. Multifunctional Pancreatic Islet Encapsulation Barriers Achieved via Multilayer PEG Hydrogels. Cell Transplant 2017; 16:1049-1057. [DOI: 10.3727/000000007783472336] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The diverse requirements for a successful islet encapsulation barrier suggest the benefit of a barrier system that presents differing functionalities to encapsulated cells and host cells. Initially, multifunctional hydrogels were synthesized via the sequential photopolymerization of PEG hydrogel layers, each with different isolated functionalities. The ability to achieve localized biological functionalities was confirmed by immunostaining of different entrapped antibodies within each hydrogel layer. Survival of murine islets macroencapsulated within the interior gel of two-layer hydrogel constructs was then assessed. Maintenance of encapsulated islet survival and function was observed within multilayer hydrogels over 28 days in culture. Additionally, the functionalization of the islet-containing interior PEG gel layer with cell–matrix moieties, with either 100 μg/ml laminin or 5 mM of the adhesive peptide IKVAV found in laminin, resulted in increased insulin secretion from encapsulated islets similar to that in gels without an exterior hydrogel layer. Finally, through cell seeding experiments, the ability of an unmodified, exterior PEG layer to prevent interactions, and thus attachment, between nonencapsulated fibroblasts and entrapped ECM components within the interior PEG layer was demonstrated. Together the presented results support the potential of multilayer hydrogels for use as multifunctional islet encapsulation barriers that provide a localized biologically active islet microenvironment, while presenting an inert, immunoprotective exterior surface to the host environment, to minimize graft–host interactions.
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Affiliation(s)
- Laney M. Weber
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0424, USA
| | - Charles Y. Cheung
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0424, USA
- Howard Hughes Medical Institute, University of Colorado, Boulder, CO, 80309-0424, USA
| | - Kristi S. Anseth
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0424, USA
- Howard Hughes Medical Institute, University of Colorado, Boulder, CO, 80309-0424, USA
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14
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Eve DJ, Sanberg PR. Article Commentary: Regenerative Medicine: An Analysis of Cell Transplantation's Impact. Cell Transplant 2017; 16:751-764. [DOI: 10.3727/000000007783465136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- David J. Eve
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery, University of South Florida College of Medicine, Tampa, FL 33612, USA
| | - Paul R. Sanberg
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery, University of South Florida College of Medicine, Tampa, FL 33612, USA
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15
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SanMartin A, Borlongan CV. Article Commentary: Cell Transplantation: Toward Cell Therapy. Cell Transplant 2017; 15:665-73. [PMID: 17176618 DOI: 10.3727/000000006783981666] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- Agneta SanMartin
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery, University of South Florida, Tampa, FL 33612, USA.
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Smink AM, de Haan BJ, Paredes-Juarez GA, Wolters AHG, Kuipers J, Giepmans BNG, Schwab L, Engelse MA, van Apeldoorn AA, de Koning E, Faas MM, de Vos P. Selection of polymers for application in scaffolds applicable for human pancreatic islet transplantation. ACTA ACUST UNITED AC 2016; 11:035006. [PMID: 27173149 DOI: 10.1088/1748-6041/11/3/035006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The liver is currently the site for transplantation of islets in humans. This is not optimal for islets, but alternative sites in humans are not available. Polymeric scaffolds in surgically accessible areas are a solution. As human donors are rare, the polymers should not interfere with functional survival of human-islets. We applied a novel platform to test the adequacy of polymers for application in scaffolds for human-islet transplantation. Viability, functionality, and immune parameters were included to test poly(D,L-lactide-co-ε-caprolactone) (PDLLCL), poly(ethylene oxide terephthalate)/polybutylene terephthalate (PEOT/PBT) block copolymer, and polysulfone. The type of polymer influenced the functional survival of human islets. In islets cultured on PDLLCL the glucagon-producing α-cells and insulin-producing β-cells contained more hormone granules than in islets in contact with PEOT/PBT or polysulfone. This was studied with ultrastructural analysis by electron microscopy (nanotomy) during 7 d of culture. PDLLCL was also associated with statistically significant lower release of double-stranded DNA (dsDNA, a so called danger-associate molecular pattern (DAMP)) from islets on PDLLCL when compared to the other polymers. DAMPs support undesired immune responses. Hydrophilicity of the polymers did not influence dsDNA release. Islets on PDLLCL also showed less cellular outgrowth. These outgrowing cells were mainly fibroblast and some β-cells undergoing epithelial to mesenchymal cell transition. None of the polymers influenced the glucose-stimulated insulin secretion. As PDLLCL was associated with less release of DAMPs, it is a promising candidate for creating a scaffold for human islets. Our study demonstrates that for sensitive, rare cadaveric donor tissue such as pancreatic islets it might be necessary to first select materials that do not influence functionality before proposing the biomaterial for in vivo application. Our presented platform may facilitate this selection of biomaterials.
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Affiliation(s)
- Alexandra M Smink
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, EA11, 9700 GZ, Groningen, The Netherlands
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Iacovacci V, Ricotti L, Menciassi A, Dario P. The bioartificial pancreas (BAP): Biological, chemical and engineering challenges. Biochem Pharmacol 2016; 100:12-27. [DOI: 10.1016/j.bcp.2015.08.107] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 08/26/2015] [Indexed: 01/05/2023]
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Johannesson B, Sui L, Freytes DO, Creusot RJ, Egli D. Toward beta cell replacement for diabetes. EMBO J 2015; 34:841-55. [PMID: 25733347 DOI: 10.15252/embj.201490685] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/22/2015] [Indexed: 12/31/2022] Open
Abstract
The discovery of insulin more than 90 years ago introduced a life-saving treatment for patients with type 1 diabetes, and since then, significant progress has been made in clinical care for all forms of diabetes. However, no method of insulin delivery matches the ability of the human pancreas to reliably and automatically maintain glucose levels within a tight range. Transplantation of human islets or of an intact pancreas can in principle cure diabetes, but this approach is generally reserved for cases with simultaneous transplantation of a kidney, where immunosuppression is already a requirement. Recent advances in cell reprogramming and beta cell differentiation now allow the generation of personalized stem cells, providing an unlimited source of beta cells for research and for developing autologous cell therapies. In this review, we will discuss the utility of stem cell-derived beta cells to investigate the mechanisms of beta cell failure in diabetes, and the challenges to develop beta cell replacement therapies. These challenges include appropriate quality controls of the cells being used, the ability to generate beta cell grafts of stable cellular composition, and in the case of type 1 diabetes, protecting implanted cells from autoimmune destruction without compromising other aspects of the immune system or the functionality of the graft. Such novel treatments will need to match or exceed the relative safety and efficacy of available care for diabetes.
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Affiliation(s)
| | - Lina Sui
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Donald O Freytes
- The New York Stem Cell Foundation Research Institute, New York, NY, USA
| | - Remi J Creusot
- Columbia Center for Translational Immunology, Department of Medicine and Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA
| | - Dieter Egli
- The New York Stem Cell Foundation Research Institute, New York, NY, USA Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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de Vos P, Lazarjani HA, Poncelet D, Faas MM. Polymers in cell encapsulation from an enveloped cell perspective. Adv Drug Deliv Rev 2014; 67-68:15-34. [PMID: 24270009 DOI: 10.1016/j.addr.2013.11.005] [Citation(s) in RCA: 186] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 08/26/2013] [Accepted: 11/13/2013] [Indexed: 02/07/2023]
Abstract
In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone), polypropylene, sodium polystyrene sulfate, and polyacrylate poly(acrylonitrile-sodium methallylsulfonate). The biocompatibility of these polymers is discussed in terms of tissue responses in both the host and matrix to accommodate the functional survival of the cells. Cells should grow and function in the polymer network as adequately as in their natural environment. This is critical when therapeutic cells from scarce cadaveric donors are considered, such as pancreatic islets. Additionally, the cell mass in capsules is discussed from the perspective of emerging new insights into the release of so-called danger-associated molecular pattern molecules by clumps of necrotic therapeutic cells. We conclude that despite two decades of intensive research, drawing conclusions about which polymer is most adequate for clinical application is still difficult. This is because of the lack of documentation on critical information, such as the composition of the polymer, the presence or absence of confounding factors that induce immune responses, toxicity to enveloped cells, and the permeability of the polymer network. Only alginate has been studied extensively and currently qualifies for application. This review also discusses critical issues that are not directly related to polymers and are not discussed in the other reviews in this issue, such as the functional performance of encapsulated cells in vivo. Physiological endocrine responses may indeed not be expected because of the many barriers that the metabolites encounter when traveling from the blood stream to the enveloped cells and back to circulation. However, despite these diffusion barriers, many studies have shown optimal regulation, allowing us to conclude that encapsulated grafts do not always follow nature's course but are still a possible solution for many endocrine disorders for which the minute-to-minute regulation of metabolites is mandatory.
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20
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Zhu HT, Wang WL, Yu L, Wang B. Pig-islet xenotransplantation: recent progress and current perspectives. Front Surg 2014; 1:7. [PMID: 25593932 PMCID: PMC4287008 DOI: 10.3389/fsurg.2014.00007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/07/2014] [Indexed: 01/23/2023] Open
Abstract
Islet xenotransplantation is one prospective treatment to bridge the gap between available human cells and needs of patients with diabetes. Pig represents an ideal candidate for obtaining such available cells. However, potential clinical application of pig islet still faces obstacles including inadequate yield of high-quality functional islets and xenorejection of the transplants. Adequate amounts of available islets can be obtained by selection of a suitable pathogen-free source herd and the development of isolation and purification method. Several studies demonstrated the feasibility of successful preclinical pig-islet xenotransplantation and provided insights and possible mechanisms of xenogeneic immune recognition and rejection. Particularly promising is the achievement of long-term insulin independence in diabetic models by means of distinct islet products and novel immunotherapeutic strategies. Nonetheless, further efforts are needed to obtain much more safety and efficacy data to translate these findings into clinic.
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Affiliation(s)
- Hai-Tao Zhu
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Wan-Li Wang
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Liang Yu
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Bo Wang
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi’an Jiaotong University, Xi’an, China
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21
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Buder B, Alexander M, Krishnan R, Chapman DW, Lakey JR. Encapsulated islet transplantation: strategies and clinical trials. Immune Netw 2013; 13:235-9. [PMID: 24385941 PMCID: PMC3875781 DOI: 10.4110/in.2013.13.6.235] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 11/26/2013] [Accepted: 11/26/2013] [Indexed: 12/01/2022] Open
Abstract
Encapsulation of tissue has been an area of intense research with a myriad number of therapeutic applications as diverse as cancer, tissue regeneration, and diabetes. In the case of diabetes, transplantation of pancreatic islets of Langerhans containing insulin-producing beta cells has shown promise toward a cure. However, anti-rejection therapy that is needed to sustain the transplanted tissue has numerous adverse effects, and the islets might still be damaged by immune processes. Furthermore, the profound scarcity of healthy human donor organs restricts the availability of islets for transplant. Islet encapsulation allows the protection of this tissue without the use of toxic medications, while also expanding the donor pool to include animal sources. Before the widespread application of this therapy, there are still issues that need to be resolved. There are many materials that can be used, differing shapes and sizes of capsules, and varied sources of islets to name a few variables that need to be considered. In this review, the current options for capsule generation, past animal and human studies, and future directions in this area of research are discussed.
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Affiliation(s)
- Brian Buder
- Department of Surgery, University of California Irvine, CA 92868, USA
| | - Michael Alexander
- Department of Surgery, University of California Irvine, CA 92868, USA
| | - Rahul Krishnan
- Department of Surgery, University of California Irvine, CA 92868, USA
| | - David W Chapman
- Department of Surgery, University of California Irvine, CA 92868, USA
| | - Jonathan Rt Lakey
- Department of Surgery, University of California Irvine, CA 92868, USA. ; Department of Biomedical Engineering, University of California Irvine, CA 92868, USA
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Long-term functions of encapsulated islets grafted in nonhuman primates without immunosuppression. Transplantation 2013; 96:624-32. [PMID: 23883970 DOI: 10.1097/tp.0b013e31829e26cf] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Long-term survival and functions of encapsulated islet grafts need to be evaluated in the absence of immunosuppression. The present study aimed to assess the viability and functions of macroencapsulated islets grafted in nonhuman primates without immunosuppression for 1 year. METHODS Islet transplantations were performed in partially pancreatectomized rhesus monkeys (two autologous and four allogenic) without immunosuppression using immunoisolatory devices. Macroencapsulated islets were implanted subcutaneously (5000-8000 IEQ/device) at two sites (left thigh and interscapular region) and were explanted at 2, 6, and 12 months after implantation. Staining for viability and apoptosis, in vivo and in vitro glucose-stimulated insulin release, expression of insulin and glucagon genes, and histopathologic examination of the device were used to assess engraftment potential, viability, and functions of islets. Animals were regularly monitored for dietary intake, body weight, and fasting blood glucose levels after islet transplantation. RESULTS Devices explanted showed vascularization at the end of 2, 6, and 12 months with occasional lymphocytes and minimal fibrosis outside the device. Flow cytometric analysis revealed 97.9%±1.5% and 94.3%±5.71% viable β cells in interscapular site and thigh in autologous recipients and 85.6%±4.01% (interscapular site) and 74.1%±12.05% (thigh) viable β cells in allogenic islet recipients. In vivo glucose challenge test revealed significantly increased glucose-stimulated insulin release (P=0.028) in the left thigh with implant (17.58±3.13 mU/L) compared with the thigh without implant (9.86±1.063 mU/L). Insulin and glucagon gene expression was evident in islets recovered from explanted device. CONCLUSIONS These results indicate that subcutaneous implantation of macroencapsulated islets is minimally invasive and has potential for transplantation without immunosuppression.
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Robles L, Storrs R, Lamb M, Alexander M, Lakey JRT. Current status of islet encapsulation. Cell Transplant 2013; 23:1321-48. [PMID: 23880554 DOI: 10.3727/096368913x670949] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cell encapsulation is a method of encasing cells in a semipermeable matrix that provides a permeable gradient for the passage of oxygen and nutrients, but effectively blocks immune-regulating cells from reaching the graft, preventing rejection. This concept has been described as early as the 1930s, but it has exhibited substantial achievements over the last decade. Several advances in encapsulation engineering, chemical purification, applications, and cell viability promise to make this a revolutionary technology. Several obstacles still need to be overcome before this process becomes a reality, including developing a reliable source of islets or insulin-producing cells, determining the ideal biomaterial to promote graft function, reducing the host response to the encapsulation device, and ultimately a streamlined, scaled-up process for industry to be able to efficiently and safely produce encapsulated cells for clinical use. This article provides a comprehensive review of cell encapsulation of islets for the treatment of type 1 diabetes, including a historical perspective, current research findings, and future studies.
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Affiliation(s)
- Lourdes Robles
- Department of Surgery, University of California Irvine, Irvine, CA, USA
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24
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Affiliation(s)
- Alexandra M Smink
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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25
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Duncanson S, Sambanis A. Dual factor delivery of CXCL12 and Exendin-4 for improved survival and function of encapsulated beta cells under hypoxic conditions. Biotechnol Bioeng 2013; 110:2292-300. [DOI: 10.1002/bit.24872] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/06/2013] [Accepted: 02/08/2013] [Indexed: 12/16/2022]
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26
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Barkai U, Weir GC, Colton CK, Ludwig B, Bornstein SR, Brendel MD, Neufeld T, Bremer C, Leon A, Evron Y, Yavriyants K, Azarov D, Zimermann B, Maimon S, Shabtay N, Balyura M, Rozenshtein T, Vardi P, Bloch K, de Vos P, Rotem A. Enhanced oxygen supply improves islet viability in a new bioartificial pancreas. Cell Transplant 2012; 22:1463-76. [PMID: 23043896 DOI: 10.3727/096368912x657341] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The current epidemic of diabetes with its overwhelming burden on our healthcare system requires better therapeutic strategies. Here we present a promising novel approach for a curative strategy that may be accessible for all insulin-dependent diabetes patients. We designed a subcutaneous implantable bioartificial pancreas (BAP)-the "β-Air"-that is able to overcome critical challenges in current clinical islet transplantation protocols: adequate oxygen supply to the graft and protection of donor islets against the host immune system. The system consists of islets of Langerhans immobilized in an alginate hydrogel, a gas chamber, a gas permeable membrane, an external membrane, and a mechanical support. The minimally invasive implantable device, refueled with oxygen via subdermally implanted access ports, completely normalized diabetic indicators of glycemic control (blood glucose intravenous glucose tolerance test and HbA1c) in streptozotocin-induced diabetic rats for periods up to 6 months. The functionality of the device was dependent on oxygen supply to the device as the grafts failed when oxygen supply was ceased. In addition, we showed that the device is immuno-protective as it allowed for survival of not only isografts but also of allografts. Histological examination of the explanted devices demonstrated morphologically and functionally intact islets; the surrounding tissue was without signs of inflammation and showed visual evidence of vasculature at the site of implantation. Further increase in islets loading density will justify the translation of the system to clinical trials, opening up the potential for a novel approach in diabetes therapy.
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Affiliation(s)
- Uriel Barkai
- Beta-O2 Technologies, Kiryat Arie, Petach Tikva, Israel.
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Improvement of islet function in a bioartificial pancreas by enhanced oxygen supply and growth hormone releasing hormone agonist. Proc Natl Acad Sci U S A 2012; 109:5022-7. [PMID: 22393012 DOI: 10.1073/pnas.1201868109] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Islet transplantation is a feasible therapeutic alternative for metabolically labile patients with type 1 diabetes. The primary therapeutic target is stable glycemic control and prevention of complications associated with diabetes by reconstitution of endogenous insulin secretion. However, critical shortage of donor organs, gradual loss in graft function over time, and chronic need for immunosuppression limit the indication for islet transplantation to a small group of patients. Here we present a promising approach to address these limitations by utilization of a macrochamber specially engineered for islet transplantation. The s.c. implantable device allows for controlled and adequate oxygen supply and provides immunological protection of donor islets against the host immune system. The minimally invasive implantable chamber normalized blood glucose in streptozotocin-induced diabetic rodents for up to 3 mo. Sufficient graft function depended on oxygen supply. Pretreatment with the growth hormone-releasing hormone (GHRH) agonist, JI-36, significantly enhanced graft function by improving glucose tolerance and increasing β-cell insulin reserve in rats thereby allowing for a reduction of the islet mass required for metabolic control. As a result of hypervascularization of the tissue surrounding the device, no relevant delay in insulin response to glucose changes has been observed. Consequently, this system opens up a fundamental strategy for therapy of diabetes and may provide a promising avenue for future approaches to xenotransplantation.
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28
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Sakata N, Sumi S, Yoshimatsu G, Goto M, Egawa S, Unno M. Encapsulated islets transplantation: Past, present and future. World J Gastrointest Pathophysiol 2012; 3:19-26. [PMID: 22368783 PMCID: PMC3284522 DOI: 10.4291/wjgp.v3.i1.19] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 12/04/2011] [Accepted: 02/08/2012] [Indexed: 02/06/2023] Open
Abstract
Islet transplantation could become an ideal treatment for severe diabetes to prevent hypoglycemia shock and irreversible diabetic complications, once some of the major and unresolved obstacles are overcome, including limited donor supplies and side effects caused by permanent immunosuppressant use. Approximately 30 years ago, some groups succeeded in improving the blood glucose of diabetic animals by transplanting encapsulated islets with semi-permeable membranes consisting of polymer. A semi-permeable membrane protects both the inner islets from mechanical stress and the recipient's immune system (both cellular and humoral immunities), while allowing bidirectional diffusion of nutrients, oxygen, glucose, hormones and wastes, i.e., immune-isolation. This device, which enables immune-isolation, is called encapsulated islets or bio-artificial pancreas. Encapsulation with a semi-permeable membrane can provide some advantages: (1) this device protects transplanted cells from the recipient's immunity even if the xenogeneic islets (from large animals such as pig) or insulin-producing cells are derived from cells that have the potential for differentiation (some kinds of stem cells). In other words, the encapsulation technique can resolve the problem of limited donor supplies; and (2) encapsulation can reduce or prevent chronic administration of immunosuppressants and, therefore, important side effects otherwise induced by immunosuppressants. And now, many novel encapsulated islet systems have been developed and are being prepared for testing in a clinical setting.
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O'Sullivan ES, Vegas A, Anderson DG, Weir GC. Islets transplanted in immunoisolation devices: a review of the progress and the challenges that remain. Endocr Rev 2011; 32:827-44. [PMID: 21951347 PMCID: PMC3591674 DOI: 10.1210/er.2010-0026] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The concept of using an immunoisolation device to facilitate the transplantation of islets without the need for immunosuppression has been around for more than 50 yr. Significant progress has been made in developing suitable materials that satisfy the need for biocompatibility, durability, and permselectivity. However, the search is ongoing for a device that allows sufficient oxygen transfer while maintaining a barrier to immune cells and preventing rejection of the transplanted tissue. Separating the islets from the rich blood supply in the native pancreas takes its toll. The immunoisolated islets commonly suffer from hypoxia and necrosis, which in turn triggers a host immune response. Efforts have been made to improve the supply of nutrients by using proangiogenic factors to augment the development of a vascular supply in the transplant site, by using small islet cell aggregates to reduce the barrier to diffusion of oxygen, or by creating scaffolds that are in close proximity to a vascular network such as the omental blood supply. Even if these efforts are successful, the shortage of donor islet tissue available for transplantation remains a major problem. To this end, a search for a renewable source of insulin-producing cells is ongoing; whether these will come from adult or embryonic stem cells or xenogeneic sources remains to be seen. Herein we will review the above issues and chart the progress made with various immunoisolation devices in small and large animal models and the small number of clinical trials carried out to date.
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Affiliation(s)
- Esther S O'Sullivan
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
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Nafea EH, Marson A, Poole-Warren LA, Martens PJ. Immunoisolating semi-permeable membranes for cell encapsulation: focus on hydrogels. J Control Release 2011; 154:110-22. [PMID: 21575662 DOI: 10.1016/j.jconrel.2011.04.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 04/21/2011] [Indexed: 12/31/2022]
Abstract
Cell-based medicine has recently emerged as a promising cure for patients suffering from various diseases and disorders that cannot be cured/treated using technologies currently available. Encapsulation within semi-permeable membranes offers transplanted cell protection from the surrounding host environment to achieve successful therapeutic function following in vivo implantation. Apart from the immunoisolation requirements, the encapsulating material must allow for cell survival and differentiation while maintaining its physico-mechanical properties throughout the required implantation period. Here we review the progress made in the development of cell encapsulation technologies from the mass transport side, highlighting the essential requirements of materials comprising immunoisolating membranes. The review will focus on hydrogels, the most common polymers used in cell encapsulation, and discuss the advantages of these materials and the challenges faced in the modification of their immunoisolating and permeability characteristics in order to optimize their function.
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Affiliation(s)
- E H Nafea
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney 2052 NSW, Australia
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Wilson JT, Cui W, Kozlovskaya V, Kharlampieva E, Pan D, Qu Z, Krishnamurthy VR, Mets J, Kumar V, Wen J, Song Y, Tsukruk VV, Chaikof EL. Cell surface engineering with polyelectrolyte multilayer thin films. J Am Chem Soc 2011; 133:7054-64. [PMID: 21491937 DOI: 10.1021/ja110926s] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach for re-engineering the molecular landscape of cell surfaces with spatially continuous and molecularly uniform ultrathin films. However, fabricating PEMs on viable cells has proven challenging owing to the high cytotoxicity of polycations. Here, we report the rational engineering of a new class of PEMs with modular biological functionality and tunable physicochemical properties which have been engineered to abrogate cytotoxicity. Specifically, we have discovered a subset of cationic copolymers that undergoes a conformational change, which mitigates membrane disruption and facilitates the deposition of PEMs on cell surfaces that are tailorable in composition, reactivity, thickness, and mechanical properties. Furthermore, we demonstrate the first successful in vivo application of PEM-engineered cells, which maintained viability and function upon transplantation and were used as carriers for in vivo delivery of PEMs containing biomolecular payloads. This new class of polymeric film and the design strategies developed herein establish an enabling technology for cell transplantation and other therapies based on engineered cells.
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Affiliation(s)
- John T Wilson
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Rago AP, Chai PR, Morgan JR. Encapsulated arrays of self-assembled microtissues: an alternative to spherical microcapsules. Tissue Eng Part A 2009; 15:387-95. [PMID: 19193131 DOI: 10.1089/ten.tea.2008.0107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Micro-encapsulation and immuno-isolation of allogenic and xenogenic tissues and cells is a promising method for the treatment of a variety of metabolic disorders. Many years have been spent optimizing spherical microcapsules, yet micro-encapsulation has not achieved its full clinical potential. As an alternative to spherical microcapsules, this study presents an alginate-encapsulated array of self-assembled three-dimensional (3D) microtissues. Monodispersed HepG2 cells were seeded onto a micro-molded agarose gel. Cells settled to the bottom of the mold recesses and self-assembled 3D microtissues (n = 822) within 24 h. This array of densely packed microtissues was encapsulated in situ using alginate. When separated from the agarose micro-mold, the encapsulated array had HepG2 microtissues in close proximity to its surface. This surface could be further modified by a simple dipping process. Microtissue size, viability, and albumin secretion were all controllable by the number of cells seeded onto the original agarose micro-mold, and microtissue shape and spacing were controllable by the design of the micro-mold. This approach to encapsulation and the use of self-assembled/self-packing 3D microtissues offers new design possibilities that may help to address certain limitations of conventional microcapsules.
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Affiliation(s)
- Adam P Rago
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA
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Johnson AS, Fisher RJ, Weir GC, Colton CK. Oxygen consumption and diffusion in assemblages of respiring spheres: Performance enhancement of a bioartificial pancreas. Chem Eng Sci 2009. [DOI: 10.1016/j.ces.2009.06.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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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: 1.9] [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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Wilson JT, Chaikof EL. Challenges and emerging technologies in the immunoisolation of cells and tissues. Adv Drug Deliv Rev 2008; 60:124-45. [PMID: 18022728 DOI: 10.1016/j.addr.2007.08.034] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Accepted: 08/13/2007] [Indexed: 12/22/2022]
Abstract
Protection of transplanted cells from the host immune system using immunoisolation technology will be important in realizing the full potential of cell-based therapeutics. Microencapsulation of cells and cell aggregates has been the most widely explored immunoisolation strategy, but widespread clinical application of this technology has been limited, in part, by inadequate transport of nutrients, deleterious innate inflammatory responses, and immune recognition of encapsulated cells via indirect antigen presentation pathways. To reduce mass transport limitations and decrease void volume, recent efforts have focused on developing conformal coatings of micron and submicron scale on individual cells or cell aggregates. Additionally, anti-inflammatory and immunomodulatory capabilities are being integrated into immunoisolation devices to generate bioactive barriers that locally modulate host responses to encapsulated cells. Continued exploration of emerging paradigms governed by the inherent challenges associated with immunoisolation will be critical to actualizing the clinical potential of cell-based therapeutics.
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Ponte GM, Baidal DA, Romanelli P, Faradji RN, Poggioli R, Cure P, Froud T, Selvaggi G, Pileggi A, Ricordi C, Alejandro R. Resolution of severe atopic dermatitis after tacrolimus withdrawal. Cell Transplant 2007; 16:23-30. [PMID: 17436852 DOI: 10.3727/000000007783464524] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Tacrolimus is an immunosuppressive agent used in solid organ and islet transplantation. Its topical form has shown benefit in the treatment of inflammatory skin conditions. Although tacrolimus has a wide spectrum of side effects, dermatological complications related to systemic tacrolimus therapy are limited in the literature. Atopic dermatitis (AD) is a chronic pruritic cutaneous condition that usually begins in infancy and is characterized by an increased Th2 response. We report the case of a patient with type 1 diabetes mellitus (T1DM) and history of AD latent for 10 years who developed severe dermatitis and alopecia 5 months after undergoing allogeneic islet transplantation and initiating a steroid-free immunosuppressive regimen with sirolimus and tacrolimus maintenance. After exclusion of other possible causes for the progression and exacerbation of the clinical presentation of AD, discontinuation of tacrolimus and introduction of mycophenolate mofetil resulted in full remission of the symptoms. The beneficial effects of tacrolimus withdrawal suggest a cause-effect relationship between this adverse event and the utilization of the drug. Islet graft function remained stable after modification of the therapeutic regimen (stable glycemic control and unchanged C-peptide).
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Affiliation(s)
- Gaston M Ponte
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
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Lim MWK, Fan TP. A "pancreatic tooth" design best accommodates the limitations of current artificial pancreas technology. Med Hypotheses 2007; 69:741-5. [PMID: 17399910 DOI: 10.1016/j.mehy.2006.08.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Accepted: 08/01/2006] [Indexed: 10/23/2022]
Abstract
Inadequately responsive glycaemic control is an important factor in the causation of diabetic end-organ damage. Artificial or hybrid bioartificial pancreases can provide responsive glycaemic control that can reduce the enormous personal suffering and socio-economic costs of diabetes. However, they share the shortcomings of limited operational life, due to depletion of stores or failure of component parts. A pancreatic tooth design provides accessibility for the purposes of replenishment or replacement. In addition, the mouth also provides a sheltered location, is more resistant to diabetic changes and less prone to thermoregulatory changes than subcutaneous tissues, and is adapted to cope with the occasional pathogen load. The device would consist of two parts: a permanent implant with an angiogenic capillary plexus that is the blood contacting interface and a crown containing the artificial or bio-artificial pancreatic systems: the accessibility of which confers ease of replenishment and replacement, among other advantages.
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Affiliation(s)
- Michael Wee-Kong Lim
- Department of Anaesthetics, Llandough Hospital, Penlan Road, Llandough CF64 2XX, United Kingdom.
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Murray PE, Garcia-Godoy F, Hargreaves KM. Regenerative endodontics: a review of current status and a call for action. J Endod 2007; 33:377-90. [PMID: 17368324 DOI: 10.1016/j.joen.2006.09.013] [Citation(s) in RCA: 523] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 09/10/2006] [Accepted: 09/18/2006] [Indexed: 12/16/2022]
Abstract
Millions of teeth are saved each year by root canal therapy. Although current treatment modalities offer high levels of success for many conditions, an ideal form of therapy might consist of regenerative approaches in which diseased or necrotic pulp tissues are removed and replaced with healthy pulp tissue to revitalize teeth. Researchers are working toward this objective. Regenerative endodontics is the creation and delivery of tissues to replace diseased, missing, and traumatized pulp. This review provides an overview of regenerative endodontics and its goals, and describes possible techniques that will allow regenerative endodontics to become a reality. These potential approaches include root-canal revascularization, postnatal (adult) stem cell therapy, pulp implant, scaffold implant, three-dimensional cell printing, injectable scaffolds, and gene therapy. These regenerative endodontic techniques will possibly involve some combination of disinfection or debridement of infected root canal systems with apical enlargement to permit revascularization and use of adult stem cells, scaffolds, and growth factors. Although the challenges of introducing endodontic tissue engineering therapies are substantial, the potential benefits to patients and the profession are equally ground breaking. Patient demand is staggering both in scope and cost, because tissue engineering therapy offers the possibility of restoring natural function instead of surgical placement of an artificial prosthesis. By providing an overview of the methodological issues required to develop potential regenerative endodontic therapies, we hope to present a call for action to develop these therapies for clinical use.
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Affiliation(s)
- Peter E Murray
- Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328, USA.
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