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Araújo-Gomes N, Zoetebier-Liszka B, van Loo B, Becker M, Nijhuis S, Smink AM, de Haan BJ, de Vos P, Karperien M, Leijten J. Microfluidic Generation of Thin-Shelled Polyethylene Glycol-Tyramine Microgels for Non-Invasive Delivery of Immunoprotected β-Cells. Adv Healthc Mater 2023:e2301552. [PMID: 37548084 DOI: 10.1002/adhm.202301552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/21/2023] [Indexed: 08/08/2023]
Abstract
Transplantation of microencapsulated pancreatic cells is emerging as a promising therapy to replenish β-cell mass lost from auto-immune nature of type I diabetes mellitus (T1DM). This strategy intends to use micrometer-sized microgels to provide immunoprotection to transplanted cells to avoid chronic application of immunosuppression. Clinical application of encapsulation has remained elusive due to often limited production throughputs and body's immunological reactions to implanted materials. This article presents a high-throughput fabrication of monodisperse, non-immunogenic, non-degradable, immunoprotective, semi-permeable, enzymatically-crosslinkable polyethylene glycol-tyramine (PEG-TA) microgels for β-cell microencapsulation. Monodisperse β-cell laden microgels of ≈120 µm, with a shell thickness of 20 µm are produced using an outside-in crosslinking strategy. Microencapsulated β-cells rapidly self-assemble into islet-sized spheroids. Immunoprotection of the microencapsulated is demonstrated by inability of FITC-IgG antibodies to diffuse into cell-laden microgels and NK-cell inability to kill microencapsulated β-cells. Multiplexed ELISA analysis on live blood immune reactivity confirms limited immunogenicity. Microencapsulated MIN6β1 spheroids remain glucose responsive for 28 days in vitro, and able to restore normoglycemia 5 days post-implantation in diabetic mice without notable amounts of cell death. In short, PEG-TA microgels effectively protect implanted cells from the host's immune system while being viable and functional, validating this strategy for the treatment of T1DM.
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Affiliation(s)
- Nuno Araújo-Gomes
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Barbara Zoetebier-Liszka
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Bas van Loo
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Malin Becker
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Suzanne Nijhuis
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Alexandra M Smink
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Bart J de Haan
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Paul de Vos
- Department of Pathology and Medical Biology, Section of Immunoendocrinology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Marcel Karperien
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
| | - Jeroen Leijten
- Department of Developmental BioEngineering, TechMed Centre, University of Twente, Drienerlolaan 5, Enschede, 7522NB, The Netherlands
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Johnson CD, Aranda-Espinoza H, Fisher JP. A Case for Material Stiffness as a Design Parameter in Encapsulated Islet Transplantation. TISSUE ENGINEERING. PART B, REVIEWS 2023; 29:334-346. [PMID: 36475851 PMCID: PMC10442690 DOI: 10.1089/ten.teb.2022.0157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
Diabetes is a disease that plagues over 463 million people globally. Approximately 40 million of these patients have type 1 diabetes mellitus (T1DM), and the global incidence is increasing by up to 5% per year. T1DM is where the body's immune system attacks the pancreas, specifically the pancreatic beta cells, with antibodies to prevent insulin production. Although current treatments such as exogenous insulin injections have been successful, exorbitant insulin costs and meticulous administration present the need for alternative long-term solutions to glucose dysregulation caused by diabetes. Encapsulated islet transplantation (EIT) is a tissue-engineered solution to diabetes. Donor islets are encapsulated in a semipermeable hydrogel, allowing the diffusion of oxygen, glucose, and insulin but preventing leukocyte infiltration and antibody access to the transplanted cells. Although successful in small animal models, EIT is still far from commercial use owing to necessary long-term systemic immunosuppressants and consistent immune rejection. Most published research has focused on tailoring the characteristics of the capsule material to promote clinical viability. However, most studies have been limited in scope to biochemical changes. Current mechanobiology studies on the effect of substrate stiffness on the function of leukocytes, especially macrophages-primary foreign body response (FBR) orchestrators, show promise in tailoring a favorable response to tissue-engineered therapies such as EIT. In this review, we explore strategies to improve the clinical viability of EIT. A brief overview of the immune system, the FBR, and current biochemical approaches will be elucidated throughout this exploration. Furthermore, an argument for using substrate stiffness as a capsule design parameter to increase EIT efficacy and clinical viability will be posed.
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Affiliation(s)
- Courtney D. Johnson
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
- Fischell Department of Bioengineering, Center for Engineering Complex Tissues, University of Maryland, College Park, Maryland, USA
| | - Helim Aranda-Espinoza
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - John P. Fisher
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
- Fischell Department of Bioengineering, Center for Engineering Complex Tissues, University of Maryland, College Park, Maryland, USA
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3
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Accolla RP, Simmons AM, Stabler CL. Integrating Additive Manufacturing Techniques to Improve Cell-Based Implants for the Treatment of Type 1 Diabetes. Adv Healthc Mater 2022; 11:e2200243. [PMID: 35412030 DOI: 10.1002/adhm.202200243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/22/2022] [Indexed: 12/12/2022]
Abstract
The increasing global prevalence of endocrine diseases like type 1 diabetes mellitus (T1DM) elevates the need for cellular replacement approaches, which can potentially enhance therapeutic durability and outcomes. Central to any cell therapy is the design of delivery systems that support cell survival and integration. In T1DM, well-established fabrication methods have created a wide range of implants, ranging from 3D macro-scale scaffolds to nano-scale coatings. These traditional methods, however, are often challenged by their inherent limitations in reproducible and discrete fabrication, particularly when scaling to the clinic. Additive manufacturing (AM) techniques provide a means to address these challenges by delivering improved control over construct geometry and microscale component placement. While still early in development in the context of T1DM cellular transplantation, the integration of AM approaches serves to improve nutrient material transport, vascularization efficiency, and the accuracy of cell, matrix, and local therapeutic placement. This review highlights current methods in T1DM cellular transplantation and the potential of AM approaches to overcome these limitations. In addition, emerging AM technologies and their broader application to cell-based therapy are discussed.
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Affiliation(s)
- Robert P. Accolla
- J. Crayton Pruitt Family Department of Biomedical Engineering University of Florida Gainesville FL 32611 USA
| | - Amberlyn M. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering University of Florida Gainesville FL 32611 USA
| | - Cherie L. Stabler
- J. Crayton Pruitt Family Department of Biomedical Engineering University of Florida Gainesville FL 32611 USA
- Department of Immunology and Pathology College of Medicine University of Florida Gainesville FL 32611 USA
- University of Florida Diabetes Institute Gainesville FL 32611 USA
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Wu S, Wang L, Fang Y, Huang H, You X, Wu J. Advances in Encapsulation and Delivery Strategies for Islet Transplantation. Adv Healthc Mater 2021; 10:e2100965. [PMID: 34480420 DOI: 10.1002/adhm.202100965] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/23/2021] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease caused by the destruction of pancreatic β-cells in response to autoimmune reactions. Shapiro et al. conducted novel islet transplantation with a glucocorticoid-free immunosuppressive agent in 2000 and achieved great success; since then, islet transplantation has been increasingly regarded as a promising strategy for the curative treatment of T1DM. However, many unavoidable challenges, such as a lack of donors, poor revascularization, blood-mediated inflammatory reactions, hypoxia, and side effects caused by immunosuppression have severely hindered the widespread application of islet transplantation in clinics. Biomaterial-based encapsulation and delivery strategies are proposed for overcoming these obstacles, and have demonstrated remarkable improvements in islet transplantation outcomes. Herein, the major problems faced by islet transplantation are summarized and updated biomaterial-based strategies for islet transplantation, including islet encapsulation across different scales, delivery of stem cell-derived beta cells, co-delivery of islets with accessory cells and immunomodulatory molecules are highlighted.
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Affiliation(s)
- Siying Wu
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510006 P. R. China
| | - Liying Wang
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510006 P. R. China
| | - Yifen Fang
- The Affiliated TCM Hospital of Guangzhou Medical University Guangzhou 511436 P. R. China
| | - Hai Huang
- Department of Urology Sun Yat‐sen Memorial Hospital Sun Yat‐sen University Guangzhou 510120 P. R. China
| | - Xinru You
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510006 P. R. China
| | - Jun Wu
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510006 P. R. China
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Stephens CH, Morrison RA, McLaughlin M, Orr K, Tersey SA, Scott-Moncrieff JC, Mirmira RG, Considine RV, Voytik-Harbin S. Oligomeric collagen as an encapsulation material for islet/β-cell replacement: effect of islet source, dose, implant site, and administration format. Am J Physiol Endocrinol Metab 2020; 319:E388-E400. [PMID: 32543944 PMCID: PMC7473915 DOI: 10.1152/ajpendo.00066.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Replacement of islets/β-cells that provide long-lasting glucose-sensing and insulin-releasing functions has the potential to restore extended glycemic control in individuals with type 1 diabetes. Unfortunately, persistent challenges preclude such therapies from widespread clinical use, including cumbersome administration via portal vein infusion, significant loss of functional islet mass upon administration, limited functional longevity, and requirement for systemic immunosuppression. Previously, fibril-forming type I collagen (oligomer) was shown to support subcutaneous injection and in situ encapsulation of syngeneic islets within diabetic mice, with rapid (<24 h) reversal of hyperglycemia and maintenance of euglycemia for beyond 90 days. Here, we further evaluated this macroencapsulation strategy, defining effects of islet source (allogeneic and xenogeneic) and dose (500 and 800 islets), injection microenvironment (subcutaneous and intraperitoneal), and macrocapsule format (injectable and preformed implantable) on islet functional longevity and recipient immune response. We found that xenogeneic rat islets functioned similarly to or better than allogeneic mouse islets, with only modest improvements in longevity noted with dosage. Additionally, subcutaneous injection led to more consistent encapsulation outcomes along with improved islet health and longevity, compared with intraperitoneal administration, whereas no significant differences were observed between subcutaneous injectable and preformed implantable formats. Collectively, these results document the benefits of incorporating natural collagen for islet/β-cell replacement therapies.
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Affiliation(s)
| | - Rachel A Morrison
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Madeline McLaughlin
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Kara Orr
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana
| | - Sarah A Tersey
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
| | | | - Raghavendra G Mirmira
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Robert V Considine
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Sherry Voytik-Harbin
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana
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Safley SA, Barber GF, Holdcraft RW, Gazda LS, Duncanson S, Poznansky MC, Sambanis A, Weber CJ. Multiple clinically relevant immunotherapies prolong the function of microencapsulated porcine islet xenografts in diabetic NOD mice without the use of anti‐CD154 mAb. Xenotransplantation 2020; 27:e12577. [DOI: 10.1111/xen.12577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Susan A. Safley
- Department of Surgery Emory University School of Medicine Atlanta GA
| | - Graham F. Barber
- Department of Surgery Emory University School of Medicine Atlanta GA
- Parker H. Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | | | | | - Stephanie Duncanson
- School of Chemical & Biomolecular Engineering Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA
- Oncorus Cambridge MA
| | - Mark C. Poznansky
- Vaccine and Immunotherapy Center Massachusetts General Hospital (East) Charlestown MA
| | - Athanassios Sambanis
- School of Chemical & Biomolecular Engineering Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA
- W. M. Keck Foundation Los Angeles CA
| | - Collin J. Weber
- Department of Surgery Emory University School of Medicine Atlanta GA
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Oxygenation strategies for encapsulated islet and beta cell transplants. Adv Drug Deliv Rev 2019; 139:139-156. [PMID: 31077781 DOI: 10.1016/j.addr.2019.05.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 04/19/2019] [Accepted: 05/04/2019] [Indexed: 02/06/2023]
Abstract
Human allogeneic islet transplantation (ITx) is emerging as a promising treatment option for qualified patients with type 1 diabetes. However, widespread clinical application of allogeneic ITx is hindered by two critical barriers: the need for systemic immunosuppression and the limited supply of human islet tissue. Biocompatible, retrievable immunoisolation devices containing glucose-responsive insulin-secreting tissue may address both critical barriers by enabling the more effective and efficient use of allogeneic islets without immunosuppression in the near-term, and ultimately the use of a cell source with a virtually unlimited supply, such as human stem cell-derived β-cells or xenogeneic (porcine) islets with minimal or no immunosuppression. However, even though encapsulation methods have been developed and immunoprotection has been successfully tested in small and large animal models and to a limited extent in proof-of-concept clinical studies, the effective use of encapsulation approaches to convincingly and consistently treat diabetes in humans has yet to be demonstrated. There is increasing consensus that inadequate oxygen supply is a major factor limiting their clinical translation and routine implementation. Poor oxygenation negatively affects cell viability and β-cell function, and the problem is exacerbated with the high-density seeding required for reasonably-sized clinical encapsulation devices. Approaches for enhanced oxygen delivery to encapsulated tissues in implantable devices are therefore being actively developed and tested. This review summarizes fundamental aspects of islet microarchitecture and β-cell physiology as well as encapsulation approaches highlighting the need for adequate oxygenation; it also evaluates existing and emerging approaches for enhanced oxygen delivery to encapsulation devices, particularly with the advent of β-cell sources from stem cells that may enable the large-scale application of this approach.
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Mourad NI, Gianello P. Long‐term culture and in vitro maturation of macroencapsulated adult and neonatal porcine islets. Xenotransplantation 2018; 26:e12461. [DOI: 10.1111/xen.12461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/03/2018] [Accepted: 08/22/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Nizar I. Mourad
- Pôle de Chirurgie Expérimentale et TransplantationUniversité Catholique de Louvain Brussels Belgium
| | - Pierre Gianello
- Pôle de Chirurgie Expérimentale et TransplantationUniversité Catholique de Louvain Brussels Belgium
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Safley SA, Kenyon NS, Berman DM, Barber GF, Willman M, Duncanson S, Iwakoshi N, Holdcraft R, Gazda L, Thompson P, Badell IR, Sambanis A, Ricordi C, Weber CJ. Microencapsulated adult porcine islets transplanted intraperitoneally in streptozotocin-diabetic non-human primates. Xenotransplantation 2018; 25:e12450. [PMID: 30117193 DOI: 10.1111/xen.12450] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 05/18/2018] [Accepted: 06/26/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Xenogeneic donors would provide an unlimited source of islets for the treatment of type 1 diabetes (T1D). The goal of this study was to assess the function of microencapsulated adult porcine islets (APIs) transplanted ip in streptozotocin (STZ)-diabetic non-human primates (NHPs) given targeted immunosuppression. METHODS APIs were encapsulated in: (a) single barium-gelled alginate capsules or (b) double alginate capsules with an inner, islet-containing compartment and a durable, biocompatible outer alginate layer. Immunosuppressed, streptozotocin-diabetic NHPs were transplanted ip with encapsulated APIs, and graft function was monitored by measuring blood glucose, %HbA1c, and porcine C-peptide. At graft failure, explanted capsules were assessed for biocompatibility and durability plus islet viability and functionality. Host immune responses were evaluated by phenotyping peritoneal cell populations, quantitation of peritoneal cytokines and chemokines, and measurement of anti-porcine IgG and IgM plus anti-Gal IgG. RESULTS NHP recipients had reduced hyperglycemia, decreased exogenous insulin requirements, and lower percent hemoglobin A1c (%HbA1c) levels. Porcine C-peptide was detected in plasma of all recipients, but these levels diminished with time. However, relatively high levels of porcine C-peptide were detected locally in the peritoneal graft site of some recipients at sacrifice. IV glucose tolerance tests demonstrated metabolic function, but the grafts eventually failed in all diabetic NHPs regardless of the type of encapsulation or the host immunosuppression regimen. Explanted microcapsules were intact, "clean," and free-floating without evidence of fibrosis at graft failure, and some reversed diabetes when re-implanted ip in diabetic immunoincompetent mice. Histology of explanted capsules showed scant evidence of a host cellular response, and viable islets could be found. Flow cytometric analyses of peritoneal cells and peripheral blood showed similarly minimal evidence of a host immune response. Preformed anti-porcine IgG and IgM antibodies were present in recipient plasma, but these levels did not rise post-transplant. Peritoneal graft site cytokine or chemokine levels were equivalent to normal controls, with the exception of minimal elevation observed for IL-6 or IL-1β, GRO-α, I-309, IP-10, and MCP-1. However, we found central necrosis in many of the encapsulated islets after graft failure, and explanted islets expressed endogenous markers of hypoxia (HIF-1α, osteopontin, and GLUT-1), suggesting a role for non-immunologic factors, likely hypoxia, in graft failure. CONCLUSIONS With donor xenoislet microencapsulation and host immunosuppression, APIs corrected hyperglycemia after ip transplantation in STZ-diabetic NHPs in the short term. The islet xenografts lost efficacy gradually, but at graft failure, some viable islets remained, substantial porcine C-peptide was detected in the peritoneal graft site, and there was very little evidence of a host immune response. We postulate that chronic effects of non-immunologic factors, such as in vivo hypoxic and hyperglycemic conditions, damaged the encapsulated islet xenografts. To achieve long-term function, new approaches must be developed to prevent this damage, for example, by increasing the oxygen supply to microencapsulated islets in the ip space.
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Affiliation(s)
- Susan A Safley
- Department of Surgery, Emory University, Atlanta, Georgia
| | - Norma S Kenyon
- Diabetes Research Institute, Miami, Florida.,Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Microbiology & Immunology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Pathology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Dora M Berman
- Diabetes Research Institute, Miami, Florida.,Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Microbiology & Immunology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Pathology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | | | - Stephanie Duncanson
- Department of Biomedical Engineering, School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Neal Iwakoshi
- Department of Surgery, Emory University, Atlanta, Georgia
| | | | | | - Peter Thompson
- Department of Surgery, Emory University, Atlanta, Georgia
| | - I Raul Badell
- Department of Surgery, Emory University, Atlanta, Georgia
| | - Athanassios Sambanis
- Department of Biomedical Engineering, School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Camillo Ricordi
- Diabetes Research Institute, Miami, Florida.,Department of Surgery, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Microbiology & Immunology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Pathology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida
| | - Collin J Weber
- Department of Surgery, Emory University, Atlanta, Georgia
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Holdcraft RW, Dumpala PR, Smith BH, Gazda LS. A model for determining an effective in vivo dose of transplanted islets based on in vitro insulin secretion. Xenotransplantation 2018; 25:e12443. [PMID: 30054944 DOI: 10.1111/xen.12443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/20/2018] [Accepted: 06/11/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Allogeneic islet transplantation for the treatment of type 1 diabetes often requires multiple implant procedures, from as many as several human pancreas donors, to achieve lasting clinical benefit. Given the limited availability of human pancreases for islet isolation, porcine islets have long been considered a potential option for clinical use. Agarose-encapsulated porcine islets (macrobeads) permit long-term culture and thus a thorough evaluation of microbiological safety and daily insulin secretory capacity, prior to implantation. The goal of this study was the development of a method for determining an effective dose of encapsulated islets based on their measured in vitro insulin secretion in a preclinical model of type 1 diabetes. METHODS Spontaneously diabetic BioBreeding diabetes-prone rats were implanted with osmotic insulin pumps in combination with continuous glucose monitoring to establish the daily insulin dose required to achieve continuous euglycaemia in individual animals. Rats were then implanted with a 1×, 2× or 3× dose (defined as the ratio of macrobead in vitro insulin secretion per 24 hours to the recipient animal's total daily insulin requirement) of porcine islet macrobeads, in the absence of immunosuppression. In vivo macrobead function was assessed by recipient non-fasted morning blood glucose values, continuous glucose monitoring and the presence of peritoneal porcine C-peptide. At the end of the study, the implanted macrobeads were removed and returned to in vitro culture for the evaluation of insulin secretion. RESULTS Diabetic rats receiving a 2× macrobead implant exhibited significantly improved blood glucose regulation compared to that of rats receiving a 1× dose during a 30-day pilot study. In a 3-month follow-up study, 2× and 3× macrobead doses initially controlled blood glucose levels equally well, although several animals receiving a 3× dose maintained euglycaemia throughout the study, compared to none of the 2× animals. The presence of porcine C-peptide in rat peritoneal fluid 3 months post-implant and the recurrence of hyperglycaemia following macrobead removal, along with the finding of persistent in vitro insulin secretion from retrieved macrobeads, confirmed long-term graft function. CONCLUSIONS Increasing dosages of islet macrobeads transplanted into diabetic rats, based on multiples of in vitro insulin secretion matched to the recipient's exogenous insulin requirements, correlated with improved blood glucose regulation and increased duration of graft function. These results demonstrate the usefulness of a standardized model for the evaluation of the functional effectiveness of islets intended for transplantation, in this case using intraperitoneally implanted agarose macrobeads, in diabetic rats. The results suggest that some features of this islet-dosing methodology may be applicable, and indeed necessary, to clinical allogeneic and xenogeneic islet transplantation.
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Affiliation(s)
| | | | - Barry H Smith
- The Rogosin Institute, New York, New York.,NewYork Presbyterian - Weill Cornell Medical Center, New York, New York
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Pancreatic Islet Transplantation Technologies: State of the Art of Micro- and Macro-Encapsulation. CURRENT TRANSPLANTATION REPORTS 2017. [DOI: 10.1007/s40472-017-0154-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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13
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Schuurman HJ. Microbiological safety of clinical xenotransplantation products: monitoring strategies and regulatory aspects. A commentary. Xenotransplantation 2016; 23:440-443. [PMID: 27859642 DOI: 10.1111/xen.12280] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 10/07/2016] [Indexed: 01/17/2023]
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Muthyala S, Safley S, Gordan K, Barber G, Weber C, Sambanis A. The effect of hypoxia on free and encapsulated adult porcine islets-an in vitro study. Xenotransplantation 2016; 24. [PMID: 28247506 DOI: 10.1111/xen.12275] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/18/2016] [Accepted: 09/07/2016] [Indexed: 12/14/2022]
Abstract
BACKGROUND Adult porcine islets (APIs) constitute a promising alternative to human islets in treating type 1 diabetes. The intrahepatic site has been used in preclinical primate studies of API xenografts; however, an estimated two-thirds of donor islets are destroyed after intraportal infusion due to a number of factors, including the instant blood-mediated inflammatory reaction (IBMIR), immunosuppressant toxicity, and poor reestablishment of extracellular matrix connections. Intraperitoneal (ip) transplantation of non-vascularized encapsulated islets offers several advantages over intrahepatic transplantation of free islets, including avoidance of IBMIR, immunoprotection, accommodation of a larger graft volume, and reduced risk of hemorrhage. However, there exists evidence that the peritoneal site is hypoxic, which likely impedes islet function. METHODS We tested the effect of hypoxia (2%-5% oxygen or pO2 : 15.2-38.0 mm Hg) on free and encapsulated APIs over a period of 6 days in culture. Free and encapsulated APIs under normoxia served as controls. Islet viability was evaluated with a viability/cytotoxicity assay using calcein AM and ethidium bromide on days 1, 3, and 6 of culture. Alamar blue assay was used to measure the metabolic activity on days 1 and 6. Insulin in spent medium was assayed by ELISA on days 1 and 6. RESULTS Viability staining indicated that free islet clusters lost their integrity and underwent severe necrosis under hypoxia; encapsulated islets remained intact, even when they began to undergo necrosis. Under hypoxia, the metabolic activity and insulin secretion (normalized to metabolic activity) of both free and encapsulated islets decreased relative to islets cultured under normoxic conditions. CONCLUSIONS Hypoxia (2%-5% oxygen or pO2 : 15.2-38.0 mm Hg) affects the viability, metabolic activity, and insulin secretion of both free and encapsulated APIs over a six-day culture period. Encapsulation augments islet integrity under hypoxia, but it does not prevent loss of viability, metabolic activity, or insulin secretion.
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Affiliation(s)
- Sudhakar Muthyala
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Susan Safley
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Kereen Gordan
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Graham Barber
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Collin Weber
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Athanassios Sambanis
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,W.M. Keck Foundation, Los Angeles, CA, USA
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15
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Retention of gene expression in porcine islets after agarose encapsulation and long-term culture. Biochem Biophys Res Commun 2016; 476:580-585. [DOI: 10.1016/j.bbrc.2016.05.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 05/30/2016] [Indexed: 12/21/2022]
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16
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Optimizing Porcine Islet Isolation to Markedly Reduce Enzyme Consumption Without Sacrificing Islet Yield or Function. Transplant Direct 2016; 2:e86. [PMID: 27830180 PMCID: PMC5087567 DOI: 10.1097/txd.0000000000000599] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 04/22/2016] [Accepted: 04/24/2016] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Human allogeneic islet transplantation for treatment of type 1 diabetes provides numerous clinical benefits, such as fewer episodes of hypoglycemic unawareness and tighter control of blood glucose levels. Availability of human pancreas for clinical and research use, however, is severely limited. Porcine pancreas offers an abundant source of tissue for optimization of islet isolation methodology and future clinical transplantation, thereby increasing patient access to this potentially lifesaving procedure. METHODS Porcine islet isolations were performed using varying amounts of collagenase (7.5, 3.75, or 2.5 Wunsch units per gram tissue) and neutral protease activity (12 000, 6000, or 4000 neutral protease units per gram tissue) and perfusion volumes (1.7 or 0.85 mL/g tissue) to assess their effects on isolation outcomes. Retention of dissociative enzymes within the pancreas during perfusion and digestion was evaluated, along with distribution of the perfusion solution within the tissue. RESULTS Reducing enzyme usage by as much as 67% and perfusion volume by 50% led to equally successful islet isolation outcomes when compared with the control group (48 ± 7% of tissue digested and 1088 ± 299 islet equivalents per gram of pancreas vs 47 ± 11% and 1080 ± 512, respectively). Using margin-marking dye in the perfusion solution to visualize enzyme distribution demonstrated that increasing perfusion volume did not improve tissue infiltration. CONCLUSIONS Current protocols for porcine islet isolation consume excessive amounts of dissociative enzymes, elevating cost and limiting research and development. These data demonstrate that islet isolation protocols can be optimized to significantly reduce enzyme usage while maintaining yield and function and thus accelerating progress toward clinical application.
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17
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Barkai U, Rotem A, de Vos P. Survival of encapsulated islets: More than a membrane story. World J Transplant 2016; 6:69-90. [PMID: 27011906 PMCID: PMC4801806 DOI: 10.5500/wjt.v6.i1.69] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/02/2015] [Accepted: 12/20/2015] [Indexed: 02/05/2023] Open
Abstract
At present, proven clinical treatments but no cures are available for diabetes, a global epidemic with a huge economic burden. Transplantation of islets of Langerhans by their infusion into vascularized organs is an experimental clinical protocol, the first approach to attain cure. However, it is associated with lifelong use of immunosuppressants. To overcome the need for immunosuppression, islets are encapsulated and separated from the host immune system by a permselective membrane. The lead material for this application is alginate which was tested in many animal models and a few clinical trials. This review discusses all aspects related to the function of transplanted encapsulated islets such as the basic requirements from a permselective membrane (e.g., allowable hydrodynamic radii, implications of the thickness of the membrane and relative electrical charge). Another aspect involves adequate oxygen supply, which is essential for survival/performance of transplanted islets, especially when using large retrievable macro-capsules implanted in poorly oxygenated sites like the subcutis. Notably, islets can survive under low oxygen tension and are physiologically active at > 40 Torr. Surprisingly, when densely crowded, islets are fully functional under hyperoxic pressure of up to 500 Torr (> 300% of atmospheric oxygen tension). The review also addresses an additional category of requirements for optimal performance of transplanted islets, named auxiliary technologies. These include control of inflammation, apoptosis, angiogenesis, and the intra-capsular environment. The review highlights that curing diabetes with a functional bio-artificial pancreas requires optimizing all of these aspects, and that significant advances have already been made in many of them.
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18
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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: 3.0] [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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19
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Burlak C, Wilhelm JJ. Xenotransplantation literature update, September-October 2014. Xenotransplantation 2014; 21:584-7. [PMID: 25382197 DOI: 10.1111/xen.12147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 10/28/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher Burlak
- Department of Surgery, Schulze Diabetes Institute, University of Minnesota, Minneapolis, MN, USA
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20
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Culturing Free-Floating and Fibrin-Embedded Islets with Endothelial Cells: Effects on Insulin Secretion and Apoptosis. Cell Mol Bioeng 2014. [DOI: 10.1007/s12195-014-0332-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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21
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Colton CK. Oxygen supply to encapsulated therapeutic cells. Adv Drug Deliv Rev 2014; 67-68:93-110. [PMID: 24582600 DOI: 10.1016/j.addr.2014.02.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 01/06/2014] [Accepted: 02/19/2014] [Indexed: 02/07/2023]
Abstract
Therapeutic cells encapsulated in immunobarrier devices have promise for treatment of a variety of human diseases without immunosuppression. The absence of sufficient oxygen supply to maintain viability and function of encapsulated tissue has been the most critical impediment to progress. Within the framework of oxygen supply limitations, we review the major issues related to development of these devices, primarily in the context of encapsulated islets of Langerhans for treating diabetes, including device designs and materials, supply of tissue, protection from immune rejection, and maintenance of cell viability and function. We describe various defensive measures investigated to enhance survival of transplanted tissue, and we review the diverse approaches to enhancement of oxygen transport to encapsulated tissue, including manipulation of diffusion distances and oxygen permeability of materials, induction of neovascularization with angiogenic factors and vascularizing membranes, and methods for increasing the oxygen concentration adjacent to encapsulated tissue so as to exceed that in the microvasculature. Recent developments, particularly in this latter area, suggest that the field is ready for clinical trials of encapsulated therapeutic cells to treat diabetes.
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22
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Gazda LS, Vinerean HV, Laramore MA, Hall RD, Carraway JW, Smith BH. No evidence of viral transmission following long-term implantation of agarose encapsulated porcine islets in diabetic dogs. J Diabetes Res 2014; 2014:727483. [PMID: 24995342 PMCID: PMC4068064 DOI: 10.1155/2014/727483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/15/2014] [Accepted: 05/18/2014] [Indexed: 12/27/2022] Open
Abstract
We have previously described the use of a double coated agarose-agarose porcine islet macrobead for the treatment of type I diabetes mellitus. In the current study, the long-term viral safety of macrobead implantation into pancreatectomized diabetic dogs treated with pravastatin (n = 3) was assessed while 2 dogs served as nonimplanted controls. A more gradual return to preimplant insulin requirements occurred after a 2nd implant procedure (days 148, 189, and >652) when compared to a first macrobead implantation (days 9, 21, and 21) in all macrobead implanted animals. In all three implanted dogs, porcine C-peptide was detected in the blood for at least 10 days following the first implant and for at least 26 days following the second implant. C-peptide was also present in the peritoneal fluid of all three implanted dogs at 6 months after 2nd implant and in 2 of 3 dogs at necropsy. Prescreening results of islet macrobeads and culture media prior to transplantation were negative for 13 viruses. No evidence of PERV or other viral transmission was found throughout the study. This study demonstrates that the long-term (2.4 years) implantation of agarose-agarose encapsulated porcine islets is a safe procedure in a large animal model of type I diabetes mellitus.
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Affiliation(s)
- Lawrence S. Gazda
- The Rogosin Institute-Xenia Division, 740 Birch Road, Xenia, OH 45385, USA
- The Rogosin Institute, New York, NY 10021, USA
- *Lawrence S. Gazda:
| | | | | | | | | | - Barry H. Smith
- The Rogosin Institute, New York, NY 10021, USA
- NewYork-Presbyterian Hospital, Weill Medical College of Cornell University, New York, NY 10021, USA
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