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Kuwabara R, Qin T, Alberto Llacua L, Hu S, Boekschoten MV, de Haan BJ, Smink AM, de Vos P. Extracellular matrix inclusion in immunoisolating alginate-based microcapsules promotes longevity, reduces fibrosis, and supports function of islet allografts in vivo. Acta Biomater 2023; 158:151-162. [PMID: 36610609 DOI: 10.1016/j.actbio.2022.12.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/14/2022] [Accepted: 12/28/2022] [Indexed: 01/06/2023]
Abstract
Immunoisolation of pancreatic-islets in alginate-microcapsules is applied to treat diabetes. However, long-term islet function is limited, which might be due to damaged and lack of contact with pancreatic extracellular matrix (ECM) components. Herein we investigated the impact of collagen IV combined with laminin sequences, either RGD, LRE, or PDSGR, on graft-survival of microencapsulated bioluminescent islets in vivo. Collagen IV with RGD had the most pronounced effect. It enhanced after 8-week implantation in immune-incompetent mice the bioluminescence of allogeneic islets by 3.2-fold, oxygen consumption rate by 14.3-fold and glucose-induced insulin release by 9.6-fold. Transcriptomics demonstrated that ECM enhanced canonical pathways involving insulin-secretion and that it suppressed pathways related to inflammation and hypoxic stress. Also, 5.8-fold fewer capsules were affected by fibrosis. In a subsequent longevity study in immune-competent mice, microencapsulated allografts containing collagen IV and RGD had a 2.4-fold higher functionality in the first week after implantation and remained at least 2.1-fold higher during the study. Islets in microcapsules containing collagen IV and RGD survived 211 ± 24.1 days while controls survived 125 ± 19.7 days. Our findings provide in vivo evidence for the efficacy of supplementing immunoisolating devices with specific ECM components to enhance functionality and longevity of islet-grafts in vivo. STATEMENT OF SIGNIFICANCE: Limitations in duration of survival of immunoisolated pancreatic islet grafts is a major obstacle for application of the technology to treat diabetes. Accumulating evidence supports that incorporation of extracellular matrix (ECM) molecules in the capsules enhances longevity of pancreatic islets. After selection of the most efficacious laminin sequence in vitro, we show in vivo that inclusion of collagen IV and RGD in alginate-based microcapsules enhances survival, insulin secretion function, and mitochondrial function. It also suppresses fibrosis by lowering proinflammatory cytokines secretion. Moreover, transcriptomic analysis shows that ECM-inclusion promotes insulin-secretion related pathways and attenuates inflammation and hypoxic stress related pathways in islets. We show that inclusion of ECM in immunoisolating devices is a promising strategy to promote long-term survival of islet-grafts.
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Affiliation(s)
- Rei Kuwabara
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands; Department of Biomaterials, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Tian Qin
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands.
| | - L Alberto Llacua
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Shuxian Hu
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Mark V Boekschoten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, Wageningen 6708 WE, the Netherlands
| | - Bart J de Haan
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Alexandra M Smink
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Paul de Vos
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
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Zhang Y, Yang J, Zhang J, Li S, Zheng L, Zhang Y, Meng H, Zhang X, Wu Z. A bio-inspired injectable hydrogel as a cell platform for real-time glycaemic regulation. J Mater Chem B 2020; 8:4627-4641. [PMID: 32373901 DOI: 10.1039/d0tb00561d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Frequent subcutaneous insulin injection and islet transplantation are promising therapeutic options for type 1 diabetes mellitus. However, poor patient compliance, insufficient appropriate islet β cell donors and body immune rejection limit their clinical applications. The design of a platform capable of encapsulating insulin-secreting cells and achieving real-time blood glucose regulation, is a so far unmet need. Herein, inspired by the natural processes of regulating blood glucose in pancreatic islet β cells, we developed a poly(N-isopropylacrylamide-co-dextran-maleic acid-co-3-acrylamidophenylboronic acid) (P(AAPBA-Dex-NIPAM)) hydrogel as a cell platform with glucose responsiveness and thermo-responsiveness for the therapy of diabetes. This platform showed good biocompatibility against insulin-secreting cells and presented glucose-dependent insulin release behaviour. The bioinspired P(AAPBA6-Dex-NIPAM64) hydrogel had a positive effect on real-time glycaemic regulation, as observed by intraperitoneal glucose tolerance tests. The non-fasting blood glucose of diabetic rats was restored to a normal level during the period of treatment. Additionally, the inflammatory response did not occur after administration of the platform. Collectively, we expected that the bio-mimetic platform combined with an insulin-secreting capability could be a new diabetic treatment strategy.
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Affiliation(s)
- Yu Zhang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China.
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Llacua LA, Faas MM, de Vos P. Extracellular matrix molecules and their potential contribution to the function of transplanted pancreatic islets. Diabetologia 2018; 61:1261-1272. [PMID: 29306997 PMCID: PMC6449002 DOI: 10.1007/s00125-017-4524-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/18/2017] [Indexed: 12/18/2022]
Abstract
Extracellular matrix (ECM) molecules are responsible for structural and biochemical support, as well as for regulation of molecular signalling and tissue repair in many organ structures, including the pancreas. In pancreatic islets, collagen type IV and VI, and laminins are the most abundant molecules, but other ECM molecules are also present. The ECM interacts with specific combinations of integrin α/β heterodimers on islet cells and guides many cellular processes. More specifically, some ECM molecules are involved in beta cell survival, function and insulin production, while others can fine tune the susceptibility of islet cells to cytokines. Further, some ECM induce release of growth factors to facilitate tissue repair. During enzymatic isolation of islets for transplantation, the ECM is damaged, impacting islet function. However, restoration of the ECM in human islets (for example by adding ECM to the interior of immunoprotective capsules) has been shown to enhance islet function. Here, we provide current insight into the role of ECM molecules in islet function and discuss the clinical potential of ECM manipulation to enhance pancreatic islet function and survival.
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Affiliation(s)
- L Alberto Llacua
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Hanzeplein 1 EA11, 9700 RB, Groningen, the Netherlands.
- University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
| | - Marijke M Faas
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Hanzeplein 1 EA11, 9700 RB, Groningen, the Netherlands
- University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Paul de Vos
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Hanzeplein 1 EA11, 9700 RB, Groningen, the Netherlands
- University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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Kim YS, Cho SW, Ko B, Shin J, Ahn CW. Alginate-Catechol Cross-Linking Interferes with Insulin Secretion Capacity in Isolated Murine Islet Cells. Diabetes Metab J 2018; 42:164-168. [PMID: 29676546 PMCID: PMC5911520 DOI: 10.4093/dmj.2018.42.2.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 12/29/2017] [Indexed: 12/11/2022] Open
Abstract
Over the past three decades, human pancreatic islet isolation and transplantation techniques have developed as a routine clinical procedure for selected patients with type 1 diabetes mellitus. However, due to the donor shortage and required chronic systemic immunosuppression, the widespread application of islet transplantation is limited. To overcome these limitations, providing a physical barrier to transplanted islet cells with encapsulating biomaterial has emerged as a promising approach to enhance engraftment and promote islet survival post-transplantation. Alginate has been considered to be a reliable biomaterial, as it enhances islet survival and does not hamper hormone secretion. Alginate-catechol (Al-CA) hydrogel was reported to provide high mechanical strength and chemical stability without deformation over a wide range of pH values. In this study, we, demonstrated, for the first time in the literature, that encapsulation of murine pancreatic islet cells with Al-CA hydrogel does not induce cytotoxicity ex vivo for an extended period; however, it does markedly abate glucose-stimulated insulin secretion. Catechol should not be considered as a constituent for alginate gelation for encapsulating islet cells in the application of islet transplantation.
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Affiliation(s)
- Yu Sik Kim
- Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Woo Cho
- Department of Biotechnology, Yonsei University, Seoul, Korea
| | - Bomin Ko
- Biomedical Research Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jisoo Shin
- Department of Biotechnology, Yonsei University, Seoul, Korea
| | - Chul Woo Ahn
- Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea
- Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
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Llacua LA, Hoek A, de Haan BJ, de Vos P. Collagen type VI interaction improves human islet survival in immunoisolating microcapsules for treatment of diabetes. Islets 2018; 10:60-68. [PMID: 29521546 PMCID: PMC5895175 DOI: 10.1080/19382014.2017.1420449] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 01/12/2023] Open
Abstract
Collagens are the most abundant fibrous protein in the human body and constitute the main structural element of the extracellular matrix. It provides mechanical and physiological support for cells. In the pancreas, collagen VI content is more than double that of collagen I or IV. It is a major component of the islet-exocrine interface and could be involved in islet-cell survival. To test the impact of collagen VI on human encapsulated pancreatic islets-cells, we tested the effects of exogenous collagen type VI on in vitro functional survival of alginate encapsulated human islet-cells. Concentrations tested ranged from 0.1 to 50 µg/ml. Islets in capsules without collagen type VI served as control. Islet-cell interaction with collagen type VI at concentrations of 0.1 and 10 µg/ml, promoted islet-cell viability (p<0.05). Although no improvement in glucose induced insulin secretion (GSIS) was observed, islets in capsules without incorporation of collagen type VI showed more dysfunction and oxygen consumption rates was improved by inclusion of collagen type VI. Our results demonstrate that incorporation of collagen type VI in immunoisolated human islets supports in vitro viability and survival of human pancreatic islets.
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Affiliation(s)
- L. Alberto Llacua
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Groningen, The Netherlands
| | - Arjan Hoek
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Groningen, The Netherlands
| | - Bart J. de Haan
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Groningen, The Netherlands
| | - Paul de Vos
- Section of Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, Groningen, The Netherlands
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6
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Abstract
The principle of immunoisolation of cells is based on encapsulation of cells in immunoprotective but semipermeable membranes that protect cells from hazardous effects of the host immune system but allows ingress of nutrients and outgress of therapeutic molecules. The technology was introduced in 1933 but has only received its deserved attention for its therapeutic application for three decades now.In the past decade important advances have been made in creating capsules that provoke minimal or no inflammatory responses. There are however new emerging challenges. These challenges relate to optimal nutrition and oxygen supply as well as standardization and documentation of capsule properties.It is concluded that the proof of principle of applicability of encapsulated grafts for treatment of human disease has been demonstrated and merits optimism about its clinical potential. Further innovation requires a much more systematic approach in identifying crucial properties of capsules and cellular grafts to allow sound interpretations of the results.
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Affiliation(s)
- Paul de Vos
- Division of Immuno-Endocrinology, Departments of Pathology and Laboratory Medicine, University of Groningen, Groningen, Groningen, The Netherlands.
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Llacua LA, de Haan BJ, de Vos P. Laminin and collagen IV inclusion in immunoisolating microcapsules reduces cytokine-mediated cell death in human pancreatic islets. J Tissue Eng Regen Med 2017; 12:460-467. [PMID: 28508555 DOI: 10.1002/term.2472] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/05/2017] [Accepted: 05/09/2017] [Indexed: 12/21/2022]
Abstract
Extracellular matrix (ECM) molecules have several functions in pancreatic islets, including provision of mechanical support and prevention of cytotoxicity during inflammation. During islet isolation, ECM connections are damaged, and are not restored after encapsulation and transplantation. Inclusion of specific combinations of collagen type IV and laminins in immunoisolating capsules can enhance survival of pancreatic islets. Here we investigated whether ECM can also enhance survival and lower susceptibility of human islets to cytokine-mediated cytotoxicity. To this end, human islets were encapsulated in alginate with collagen IV and either RGD, LRE or PDSGR, i.e. laminin sequences. Islets in capsules without ECM served as control. The encapsulated islets were exposed to IL-1β, IFN-γ and TNF-α for 24 and 72 h. All combinations of ECM improved the islet cell survival, and reduced necrosis and apoptosis after cytokine exposure (P < 0.01). Collagen IV-RGD and collagen IV-LRE reduced danger-associated molecular patterns (DAMPs) release from islets (P < 0.05). Moreover, collagen IV-RGD and collagen IV-PDSGR, but not collagen IV-LRE, reduced NO release from encapsulated human islets (P < 0.05). This reduction correlated with a higher oxygen consumption rate (OCR) of islets in capsules containing collagen IV-RGD and collagen IV-PDSGR. Islets in capsules with collagen IV-LRE showed more dysfunction, and OCR was not different from islets in control capsules without ECM. Our study demonstrates that incorporation of specific ECM molecules such as collagen type IV with the laminin sequences RGD and PDSGR in immunoisolated islets can protect against cytokine toxicity.
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Affiliation(s)
- L Alberto Llacua
- Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen and University Medical Center Groningen, RB, Groningen, The Netherlands
| | - Bart J de Haan
- Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen and University Medical Center Groningen, RB, Groningen, The Netherlands
| | - Paul de Vos
- Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen and University Medical Center Groningen, RB, Groningen, The Netherlands
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8
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Mooranian A, Negrulj R, Takechi R, Jamieson E, Morahan G, Al-Salami H. New Biotechnological Microencapsulating Methodology Utilizing Individualized Gradient-Screened Jet Laminar Flow Techniques for Pancreatic β-Cell Delivery: Bile Acids Support Cell Energy-Generating Mechanisms. Mol Pharm 2017; 14:2711-2718. [DOI: 10.1021/acs.molpharmaceut.7b00220] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Armin Mooranian
- Biotechnology
and Drug Development Research Laboratory, School of Pharmacy, Curtin
Health Innovation Research Institute, Curtin University, Perth, Western Australia 6102, Australia
| | - Rebecca Negrulj
- Biotechnology
and Drug Development Research Laboratory, School of Pharmacy, Curtin
Health Innovation Research Institute, Curtin University, Perth, Western Australia 6102, Australia
| | - Ryu Takechi
- School
of Public Health, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia 6102, Australia
| | - Emma Jamieson
- Centre
for Diabetes Research, Harry Perkins Institute of Medical Research, Perth, Western Australia 6009, Australia
| | - Grant Morahan
- Centre
for Diabetes Research, Harry Perkins Institute of Medical Research, Perth, Western Australia 6009, Australia
| | - Hani Al-Salami
- Biotechnology
and Drug Development Research Laboratory, School of Pharmacy, Curtin
Health Innovation Research Institute, Curtin University, Perth, Western Australia 6102, Australia
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9
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Borlongan CV, Yu G, Matsukawa N, Yasuhara T, Hara K, Xu L. Article Commentary: Cell Transplantation: Stem Cells in the Spotlight. Cell Transplant 2017; 14:519-526. [DOI: 10.3727/000000005783982774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- Cesar V. Borlongan
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
| | - Guolong Yu
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
| | - Noriyuki Matsukawa
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
| | - Takao Yasuhara
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
| | - Koichi Hara
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
| | - Lin Xu
- Neurology/Insttitute of Molecular Medicind & Genetics/School of Graduate Studies, Medical College of Georgia, Augusta, GA, USA
- Research/Affiliations Service Line, Augusta VAMC, Augusta, GA, USA
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Sanberg PR, Greene-Zavertnik C, Davis CD. Article Commentary: Cell Transplantation: The Regenerative Medicine Journal. A Biennial Analysis of Publications. Cell Transplant 2017; 12:815-825. [DOI: 10.3727/000000003771000165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Paul R. Sanberg
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
| | - Cathryn Greene-Zavertnik
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
| | - Cyndy D. Davis
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
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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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Llacua A, de Haan BJ, Smink SA, de Vos P. Extracellular matrix components supporting human islet function in alginate-based immunoprotective microcapsules for treatment of diabetes. J Biomed Mater Res A 2016; 104:1788-96. [PMID: 26990360 DOI: 10.1002/jbm.a.35706] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/16/2016] [Accepted: 03/02/2016] [Indexed: 02/06/2023]
Abstract
In the pancreas, extracellular matrix (ECM) components play an import role in providing mechanical and physiological support, and also contribute to the function of islets. These ECM-connections are damaged during islet-isolation from the pancreas and are not fully recovered after encapsulation and transplantation. To promote the functional survival of human pancreatic islets, we tested different ECMs molecules in alginate-encapsulated human islets. These were laminin derived recognition sequences, IKVAV, RGD, LRE, PDSGR, collagen I sequence DGEA (0.01 - 1.0 mM), and collagen IV (50 - 200 µg/mL). Interaction with RGD and PDSGR promoted islet viability and glucose induced insulin secretion (GIIS) when it was applied at concentrations ranging from 0.01 - 1.0 mM (p < 0.05). Also the laminin sequence LRE contributed to enhanced GIIS but only at higher concentrations of 1 mM (p < 0.05). Collagen IV also had beneficial effects but only at 50 µg/ml and no further improvement was observed at higher concentrations. IKVAV and DGEA had no effects on human islets. Synergistic effects were observed by adding Collagen(IV)-RGD, Collagen(IV)-LRE, and Collagen(IV)-PDSGR to encapsulated human islets. Our results demonstrate the potential of specific ECM components in support of functional survival of human encapsulated and free islet grafts. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1788-1796, 2016.
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Affiliation(s)
- Alberto Llacua
- Department of Pathology and Medical Biology, Immunoendocrinology, University of Groningen, Hanzeplein 1, Groningen, RB, 9700, The Netherlands
| | - Bart J de Haan
- Department of Pathology and Medical Biology, Immunoendocrinology, University of Groningen, Hanzeplein 1, Groningen, RB, 9700, The Netherlands
| | - Sandra A Smink
- Department of Pathology and Medical Biology, Immunoendocrinology, University of Groningen, Hanzeplein 1, Groningen, RB, 9700, The Netherlands
| | - Paul de Vos
- Department of Pathology and Medical Biology, Immunoendocrinology, University of Groningen, Hanzeplein 1, Groningen, RB, 9700, The Netherlands
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de Vos P, Smink AM, Paredes G, Lakey JRT, Kuipers J, Giepmans BNG, de Haan BJ, Faas MM. Enzymes for Pancreatic Islet Isolation Impact Chemokine-Production and Polarization of Insulin-Producing β-Cells with Reduced Functional Survival of Immunoisolated Rat Islet-Allografts as a Consequence. PLoS One 2016; 11:e0147992. [PMID: 26824526 PMCID: PMC4732769 DOI: 10.1371/journal.pone.0147992] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
The primary aim of this study was to determine whether normal variations in enzyme-activities of collagenases applied for rat-islet isolation impact longevity of encapsulated islet grafts. Also we studied the functional and immunological properties of rat islets isolated with different enzyme preparations to determine whether this impacts these parameters. Rat-islets were isolated from the pancreas with two different collagenases with commonly accepted collagenase, neutral protease, and clostripain activities. Islets had a similar and acceptable glucose-induced insulin-release profile but a profound statistical significant difference in production of the chemokines IP-10 and Gro-α. The islets were studied with nanotomy which is an EM-based technology for unbiased study of ultrastructural features of islets such as cell-cell contacts, endocrine-cell condition, ER stress, mitochondrial conditions, and cell polarization. The islet-batch with higher chemokine-production had a lower amount of polarized insulin-producing β-cells. All islets had more intercellular spaces and less interconnected areas with tight cell-cell junctions when compared to islets in the pancreas. Islet-graft function was studied by implanting encapsulated and free islet grafts in rat recipients. Alginate-based encapsulated grafts isolated with the enzyme-lot inducing higher chemokine production and lower polarization survived for a two-fold shorter period of time. The lower survival-time of the encapsulated grafts was correlated with a higher influx of inflammatory cells at 7 days after implantation. Islets from the same two batches transplanted as free unencapsulated-graft, did not show any difference in survival or function in vivo. Lack of insight in factors contributing to the current lab-to-lab variation in longevity of encapsulated islet-grafts is considered to be a threat for clinical application. Our data suggest that seemingly minor variations in activity of enzymes applied for islet-isolation might contribute to longevity-variations of immunoisolated islet-grafts.
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Affiliation(s)
- Paul de Vos
- Immunoendocrinology, department of Pathology and Medical biology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
- * E-mail:
| | - Alexandra M. Smink
- Immunoendocrinology, department of Pathology and Medical biology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Genaro Paredes
- Immunoendocrinology, department of Pathology and Medical biology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Jonathan R. T. Lakey
- Department of Surgery and Biomedical Engineering, University of California Irvine, Orange, CA, 92868, United States of America
| | - Jeroen Kuipers
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, P. O. Box 196, 9700 AD, Groningen, The Netherlands
| | - Ben N. G. Giepmans
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, P. O. Box 196, 9700 AD, Groningen, The Netherlands
| | - Bart J. de Haan
- Immunoendocrinology, department of Pathology and Medical biology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Marijke M. Faas
- Immunoendocrinology, department of Pathology and Medical biology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
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Song S, Roy S. Progress and challenges in macroencapsulation approaches for type 1 diabetes (T1D) treatment: Cells, biomaterials, and devices. Biotechnol Bioeng 2016; 113:1381-402. [PMID: 26615050 DOI: 10.1002/bit.25895] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/30/2015] [Accepted: 11/24/2015] [Indexed: 12/15/2022]
Abstract
Macroencapsulation technology has been an attractive topic in the field of treatment for Type 1 diabetes due to mechanical stability, versatility, and retrievability of the macro-capsule design. Macro-capsules can be categorized into extravascular and intravascular devices, in which solute transport relies either on diffusion or convection, respectively. Failure of macroencapsulation strategies can be due to limited regenerative capacity of the encased insulin-producing cells, sub-optimal performance of encapsulation biomaterials, insufficient immunoisolation, excessive blood thrombosis for vascular perfusion devices, and inadequate modes of mass transfer to support cell viability and function. However, significant technical advancements have been achieved in macroencapsulation technology, namely reducing diffusion distance for oxygen and nutrients, using pro-angiogenic factors to increase vascularization for islet engraftment, and optimizing membrane permeability and selectivity to prevent immune attacks from host's body. This review presents an overview of existing macroencapsulation devices and discusses the advances based on tissue-engineering approaches that will stimulate future research and development of macroencapsulation technology. Biotechnol. Bioeng. 2016;113: 1381-1402. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Shang Song
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158.
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A novel multilayer immunoisolating encapsulation system overcoming protrusion of cells. Sci Rep 2014; 4:6856. [PMID: 25358640 PMCID: PMC4215319 DOI: 10.1038/srep06856] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/10/2014] [Indexed: 12/23/2022] Open
Abstract
Application of alginate-microencapsulated therapeutic cells is a promising approach for diseases that require a local and constant supply of therapeutic molecules. However most conventional alginate microencapsulation systems are associated with low mechanical stability and protrusion of cells which is associated with higher surface roughness and limits their clinical application. Here we have developed a novel multilayer encapsulation system that prevents cells from protruding from capsules. The system was tested using a therapeutic protein with anti-tumor activity overexpressed in mammalian cells. The cell containing core of the multilayer capsule was formed by flexible alginate, creating a cell sustaining environment. Surrounded by a poly-L-lysine layer the flexible core was enveloped in a high-G alginate matrix that is less flexible and has higher mechanical stability, which does not support cell survival. The cells in the core of the multilayer capsule did not show growth impairment and protein production was normal for periods up to 70 days in vitro. The additional alginate layer also lowered the surface roughness compared to conventional cell containing alginate-PLL capsules. Our system provides a solution for two important, often overlooked phenomena in cell encapsulation: preventing cell protrusion and improving surface roughness.
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Spasojevic M, Paredes-Juarez GA, Vorenkamp J, de Haan BJ, Schouten AJ, de Vos P. Reduction of the inflammatory responses against alginate-poly-L-lysine microcapsules by anti-biofouling surfaces of PEG-b-PLL diblock copolymers. PLoS One 2014; 9:e109837. [PMID: 25347191 PMCID: PMC4209974 DOI: 10.1371/journal.pone.0109837] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 09/03/2014] [Indexed: 01/12/2023] Open
Abstract
Large-scale application of alginate-poly-L-lysine (alginate-PLL) capsules used for microencapsulation of living cells is hampered by varying degrees of success, caused by tissue responses against the capsules in the host. A major cause is proinflammatory PLL which is applied at the surface to provide semipermeable properties and immunoprotection. In this study, we investigated whether application of poly(ethylene glycol)-block-poly(L-lysine hydrochloride) diblock copolymers (PEG-b-PLL) can reduce the responses against PLL on alginate-matrices. The application of PEG-b-PLL was studied in two manners: (i) as a substitute for PLL or (ii) as an anti-biofouling layer on top of a proinflammatory, but immunoprotective, semipermeable alginate-PLL100 membrane. Transmission FTIR was applied to monitor the binding of PEG-b-PLL. When applied as a substitute for PLL, strong host responses in mice were observed. These responses were caused by insufficient binding of the PLL block of the diblock copolymers confirmed by FTIR. When PEG-b-PLL was applied as an anti-biofouling layer on top of PLL100 the responses in mice were severely reduced. Building an effective anti-biofouling layer required 50 hours as confirmed by FTIR, immunocytochemistry and XPS. Our study provides new insight in the binding requirements of polyamino acids necessary to provide an immunoprotective membrane. Furthermore, we present a relatively simple method to mask proinflammatory components on the surface of microcapsules to reduce host responses. Finally, but most importantly, our study illustrates the importance of combining physicochemical and biological methods to understand the complex interactions at the capsules' surface that determine the success or failure of microcapsules applicable for cell-encapsulation.
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Affiliation(s)
- Milica Spasojevic
- Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
- Departments of Pathology and Laboratory Medicine, section of Medical Biology, division of immunoendocrinology, University of Groningen, Groningen, The Netherlands
| | - Genaro A. Paredes-Juarez
- Departments of Pathology and Laboratory Medicine, section of Medical Biology, division of immunoendocrinology, University of Groningen, Groningen, The Netherlands
| | - Joop Vorenkamp
- Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Bart J. de Haan
- Departments of Pathology and Laboratory Medicine, section of Medical Biology, division of immunoendocrinology, University of Groningen, Groningen, The Netherlands
| | - Arend Jan Schouten
- Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Paul de Vos
- Departments of Pathology and Laboratory Medicine, section of Medical Biology, division of immunoendocrinology, University of Groningen, Groningen, The Netherlands
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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: 18.6] [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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Safley SA, Cui H, Cauffiel SMD, Xu BY, Wright JR, Weber CJ. Encapsulated piscine (tilapia) islets for diabetes therapy: studies in diabetic NOD and NOD-SCID mice. Xenotransplantation 2014; 21:127-39. [PMID: 24635017 DOI: 10.1111/xen.12086] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/20/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Our goal was to improve islet transplantation as a therapy for patients with type I diabetes mellitus. Because human donor islets are scarce, we are studying islet xenografts in the diabetic NOD mouse model. We hypothesize that optimal xenoislet survival will be achieved by the combination of donor islet immunoisolation with recipient immunosuppression. We and others have studied adult and neonatal porcine islets as sources of tissue for microencapsulated islet xenografts, but we believe it is also advantageous to consider using islets from fish, which can be raised in large numbers relatively quickly and economically. Therefore, in this study, we have evaluated the function of microencapsulated xenogeneic piscine (tilapia) islets transplanted intraperitoneally (IP) in NOD mice in the presence of CD4(+) T-cell depletion and/or costimulatory blockade. METHODS Spontaneously diabetic NOD mice or streptozotocin (STZ)-diabetic NOD-SCID mice were transplanted IP with microencapsulated tilapia islets. Recipient immunosuppression included anti-CD4 mAb, CTLA4-Ig, anti-CD80 mAb, anti-CD86 mAb, or anti-CD154 mAb, alone or in combination. Graft function was evaluated by blood glucose (BG) levels, intravenous (IV) and oral glucose tolerance tests (GTTs), histologic and immunohistochemical analyses of grafts, and flow cytometric analysis of peritoneal cells. RESULTS Encapsulated tilapia islets normalized random BG levels for up to 210 days in NOD-SCID mice. In diabetic NOD mice, encapsulated tilapia islets were rejected on day 11 ± 4 with a peritoneal infiltrate of macrophages, eosinophils, B cells, occasional neutrophils, but few T cells. Immunohistochemical staining demonstrated the presence of murine IgG on tilapia islets within capsules of rejecting, non-immunosuppressed mice, as well as murine IgG-positive lymphocytes in the layer of host cells surrounding those capsules. These findings suggested that our barium (Ba)-gelled alginate capsules are permeable to IgG and that anti-piscine antibodies may be involved in the rejection of encapsulated tilapia islets in untreated mice. No single immunosuppressive agent prolonged encapsulated tilapia islet survival in NOD mice, but the combination of CTLA4-Ig plus anti-CD154 mAb extended tilapia islet graft survival until rejection at 119 ± 20 days and inhibited host cell recruitment to the peritoneal cavity. Triple treatment with CTLA4-Ig, anti-CD154 mAb, and anti-CD4 mAb allowed graft survival for 157 ± 35 days with little evidence of a host cellular reaction. IV and oral glucose tolerance tests (GTTs) of recipients with functioning xenografts demonstrated remarkably normal metabolic function. CONCLUSIONS We conclude that microencapsulated tilapia islets can survive long term with excellent metabolic control in diabetic mice given targeted immunosuppression, suggesting that cross-species physiological incompatibility may not compromise the applicability of this novel approach for future clinical applications. We predict that an improved microcapsule that prevents the entrance of IgG will enhance tilapia islet survival in this model, possibly allowing the application of this technique with limited or no immunosuppression.
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Affiliation(s)
- Susan A Safley
- Department of Surgery, Emory University, Atlanta, GA, USA
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19
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Spasojevic M, Bhujbal S, Paredes G, de Haan BJ, Schouten AJ, de Vos P. Considerations in binding diblock copolymers on hydrophilic alginate beads for providing an immunoprotective membrane. J Biomed Mater Res A 2013; 102:1887-96. [PMID: 23853069 PMCID: PMC4232034 DOI: 10.1002/jbm.a.34863] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/13/2013] [Accepted: 06/28/2013] [Indexed: 01/14/2023]
Abstract
Alginate-based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab-to-lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly-l-lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)-block-poly(l-lysine hydrochloride) (PEG454-b-PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454-b-PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP-1 monocytes was observed with both PLL and PEG454-b-PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties.
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Affiliation(s)
- Milica Spasojevic
- Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen, 9747, AG Groningen, the Netherlands; Departments of Pathology and Laboratory Medicine, Section of Medical Biology, Division of Immunoendocrinology, University of Groningen, Hanzeplein 1, 9700, RB Groningen, The Netherlands
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Acarregui A, Murua A, Pedraz JL, Orive G, Hernández RM. A Perspective on Bioactive Cell Microencapsulation. BioDrugs 2012; 26:283-301. [DOI: 10.1007/bf03261887] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Sobol M, Bartkowiak A, de Haan B, de Vos P. Cytotoxicity study of novel water-soluble chitosan derivatives applied as membrane material of alginate microcapsules. J Biomed Mater Res A 2012. [PMID: 23203606 DOI: 10.1002/jbm.a.34500] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The majority of cell encapsulation systems applied so far are based on polyelectrolyte complexes of alginate and polyvalent metal cations. Although widely used, these systems suffer from the risk of disintegration. This can be partially solved by applying chitosan as additional outer membrane. However, chitosan can be dissolved in water only at a low pH, which limits its use in the field of bioencapsulation. In this study, novel primary and tertiary amine chitosan derivatives have been synthesized, which may be dissolved at pH 7.0, and retain the ability to effectively form additional membrane on the surface of alginate beads. As aqueous solutions tertiary amines dimethylamino-1-propyl-chitosan and dimethylethylamine-chitosan with linear hydrochloride aliphatic chains had the lowest toxicity, whereas dimethylpropylamine-chitosan, diethylaminoethyl-chitosan, and diisopropylaminoethyl-chitosan with branched hydrochloride aliphatic were cytotoxic to the majority of tested cells. When applied as polyelectrolyte complexation agent on the surface of alginate beads, none of the derivates had any negative effect on the metabolic activity of encapsulated beta-cells.
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Affiliation(s)
- Marcin Sobol
- Center of Bioimmobilisation and Innovative Packaging Materials, West Pomeranian University of Technology, Szczecin 71270, Poland.
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22
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Williams S, Schwasinger-Schmidt T, Zamierowski D, Stehno-Bittel L. Diffusion into human islets is limited to molecules below 10kDa. Tissue Cell 2012; 44:332-41. [DOI: 10.1016/j.tice.2012.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 05/14/2012] [Accepted: 05/25/2012] [Indexed: 11/30/2022]
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de Vos P, Spasojevic M, de Haan BJ, Faas MM. The association between in vivo physicochemical changes and inflammatory responses against alginate based microcapsules. Biomaterials 2012; 33:5552-9. [DOI: 10.1016/j.biomaterials.2012.04.039] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 04/13/2012] [Indexed: 12/20/2022]
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Soejitno A, Prayudi PKA. The prospect of induced pluripotent stem cells for diabetes mellitus treatment. Ther Adv Endocrinol Metab 2011; 2:197-210. [PMID: 23148185 PMCID: PMC3474639 DOI: 10.1177/2042018811420198] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A continuous search for a permanent cure for diabetes mellitus is underway with several remarkable discoveries over the past few decades. One of these is the potential of pancreatic stem/progenitor cells to rejuvenate functional β cells. However, the existence of these cell populations is still obscure and a lack of phenotype characterization hampers their use in clinical settings. Cellular reprogramming through induced pluripotent stem (iPS) cell technology can become an alternative strategy to generate insulin-producing cells in a relatively safe (autologous-derived cells, thus devoid of rejection risk) and efficient way (high cellular proliferation) but retain a precise morphological and genetic composition, similar to that of the native β cells. iPS cell technology is a technique of transducing any cell types with key transcription factors to yield embryonic-like stem cells with high clonogenicity and is able to give rise into all cell lineages from three germ layers (endoderm, ectoderm, and mesoderm). This approach can generate β-like pancreatic cells that are fully functional as proven by either in vitro or in vivo studies. This novel proof-of-concept stem cell technology brings new expectations on applying stem cell therapy for diabetes mellitus in clinical settings.
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Affiliation(s)
- Andreas Soejitno
- Department of Molecular Medicine and Stem Cell Research, Faculty of Medicine Udayana University, Denpasar, Indonesia
| | - Pande Kadek Aditya Prayudi
- Department of Molecular Medicine and Stem Cell Research, Faculty of Medicine Udayana University, Denpasar, Indonesia
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Vaithilingam V, Quayum N, Joglekar MV, Jensen J, Hardikar AA, Oberholzer J, Guillemin GJ, Tuch BE. Effect of alginate encapsulation on the cellular transcriptome of human islets. Biomaterials 2011; 32:8416-25. [PMID: 21889795 DOI: 10.1016/j.biomaterials.2011.06.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 06/20/2011] [Indexed: 10/17/2022]
Abstract
Encapsulation of human islets may prevent their immune rejection when transplanted into diabetic recipients. To assist in understanding why clinical outcomes with encapsulated islets were not ideal, we examined the effect of encapsulation on their global gene (mRNA) and selected miRNAs (non-coding (nc)RNA) expression. For functional studies, encapsulated islets were transplanted into peritoneal cavity of diabetic NOD-SCID mice. Genomics analysis and transplantation studies demonstrate that islet origin and isolation centres are a major source of variation in islet quality. In contrast, tissue culture and the encapsulation process had only a minimal effect, and did not affect islet viability. Microarray analysis showed that as few as 29 genes were up-regulated and 2 genes down-regulated (cut-off threshold 0.1) by encapsulation. Ingenuity analysis showed that up-regulated genes were involved mostly in inflammation, especially chemotaxis, and vascularisation. However, protein expression of these factors was not altered by encapsulation, raising doubts about the biosignificance of the gene changes. Encapsulation had no effect on levels of islet miRNAs. In vivo studies indicate differences among the centres in the quality of the islets isolated. We conclude that microencapsulation of human islets with barium alginate has little effect on their transcriptome.
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26
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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: 56] [Impact Index Per Article: 4.3] [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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27
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Barnett BP, Ruiz-Cabello J, Hota P, Liddell R, Walczak P, Howland V, Chacko VP, Kraitchman DL, Arepally A, Bulte JWM. Fluorocapsules for improved function, immunoprotection, and visualization of cellular therapeutics with MR, US, and CT imaging. Radiology 2010; 258:182-91. [PMID: 20971778 DOI: 10.1148/radiol.10092339] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To develop novel immunoprotective alginate microcapsule formulations containing perfluorocarbons (PFCs) that may increase cell function, provide immunoprotection for xenografted cells, and simultaneously enable multimodality imaging. MATERIALS AND METHODS All animal experiments were approved by an Institutional Animal Care and Use Committee. Cadaveric human islet cells were encapsulated with alginate, poly-l-lysine, and perfluorooctyl bromide (PFOB) or perfluoropolyether (PFPE). In vitro viability and the glucose-stimulation index for insulin were determined over the course of 2 weeks and analyzed by using a cross-sectional time series regression model. The sensitivity of multimodality (computed tomography [CT], ultrasonography [US], and fluorine 19 [(19)F] magnetic resonance [MR] imaging) detection was determined for fluorocapsules embedded in gel phantoms. C57BL/6 mice intraperitoneally receiving 6000 PFOB-labeled (n = 6) or 6000 PFPE-labeled (n = 6) islet-containing fluorocapsules and control mice intraperitoneally receiving 6000 PFOB-labeled (n = 6) or 6000 PFPE-labeled (n = 6) fluorocapsules without islets were monitored for human C-peptide (insulin) secretion during a period of 55 days. Mice underwent (19)F MR imaging at 9.4 T and micro-CT. Swine (n = 2) receiving 9000 PFOB capsules through renal artery catheterization were imaged with a clinical multidetector CT scanner. Signal intensity was evaluated by using a paired t test. RESULTS Compared with nonfluorinated alginate microcapsules, PFOB fluorocapsules increased insulin secretion of encapsulated human islets, with values up to 18.5% (3.78 vs 3.19) at 8-mmol/L glucose concentration after 7 days in culture (P < .001). After placement of the immunoprotected encapsulated cells into mice, a sustained insulin release was achieved with human C-peptide levels of 19.1 pmol/L ± 0.9 (standard deviation) and 33.0 pmol/L ± 1.0 for PFPE and PFOB capsules, respectively. Fluorocapsules were readily visualized with (19)F MR imaging, US imaging, and CT with research- and clinical-grade imagers for all modalities. CONCLUSION Fluorocapsules enhance glucose responsiveness and insulin secretion in vitro, enable long-term insulin secretion by xenografted islet cells in vivo, and represent a novel contrast agent platform for multimodality imaging.
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Affiliation(s)
- Brad P Barnett
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, 720 Rutland Ave, 217 Traylor, Baltimore, MD 21205, USA
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Abstract
Clinical islet transplantation (CIT), the infusion of allogeneic islets within the liver, has the potential to provide precise and sustainable control of blood glucose levels for the treatment of type 1 diabetes. The success and long-term outcomes of CIT, however, are limited by obstacles such as a nonoptimal transplantation site and severe inflammatory and immunological responses to the transplant. Tissue engineering strategies are poised to combat these challenges. In this review, emerging methods for engineering an optimal islet transplantation site, as well as novel approaches for improving islet cell encapsulation, are discussed.
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Affiliation(s)
- Jaime A Giraldo
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, Florida, USA
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Su J, Hu BH, Lowe WL, Kaufman DB, Messersmith PB. Anti-inflammatory peptide-functionalized hydrogels for insulin-secreting cell encapsulation. Biomaterials 2009; 31:308-14. [PMID: 19782393 DOI: 10.1016/j.biomaterials.2009.09.045] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 09/11/2009] [Indexed: 11/19/2022]
Abstract
Pancreatic islet encapsulation within semi-permeable materials has been proposed for transplantation therapy of type I diabetes mellitus. Polymer hydrogel networks used for this purpose have been shown to provide protection from islet destruction by immunoreactive cells and antibodies. However, one of the fundamental deficiencies with current encapsulation methods is that the permselective barriers cannot protect islets from cytotoxic molecules of low molecular weight that are diffusible into the capsule material, which subsequently results in beta-cell destruction. Use of materials that can locally inhibit the interaction between the permeable small cytotoxic factors and islet cells may prolong the viability and function of encapsulated islet grafts. Here we report the design of anti-inflammatory hydrogels supporting islet cell survival in the presence of diffusible pro-inflammatory cytokines. We demonstrated that a poly(ethylene glycol)-containing hydrogel network, formed by native chemical ligation and presenting an inhibitory peptide for islet cell surface IL-1 receptor, was able to maintain the viability of encapsulated islet cells in the presence of a combination of cytokines including IL-1 beta, TNF-alpha, and INF-gamma. In stark contrast, cells encapsulated in unmodified hydrogels were mostly destroyed by cytokines which diffused into the capsules. At the same time, these peptide-modified hydrogels were able to efficiently protect encapsulated cells against beta-cell specific T-lymphocytes and maintain glucose-stimulated insulin release by islet cells. With further development, the approach of encapsulating cells and tissues within hydrogels presenting anti-inflammatory agents may represent a new strategy to improve cell and tissue graft function in transplantation and tissue engineering applications.
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Affiliation(s)
- Jing Su
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
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30
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Fort A, Fort N, Ricordi C, Stabler CL. Biohybrid devices and encapsulation technologies for engineering a bioartificial pancreas. Cell Transplant 2009; 17:997-1003. [PMID: 19177836 DOI: 10.3727/096368908786991498] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The use of cell-based treatments in the field of metabolic organs, particularly the pancreas, has seen tremendous growth in recent years. The transplantation of islet of Langerhans cells for the treatment of type 1 diabetes mellitus (T1DM) has allowed for natural glycemic control for patients plagued with hypoglycemia unawareness. The transplantation of islet cells into the portal vein of the liver, however, has presented challenges to the survival of the cells due to inflammation, vascularization, the need for systemic immunosuppression, and physical stress on the graft. New advances in the engineering of appropriate biohybrid devices and encapsulation technologies have led to promising alternatives to traditional methods.
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Affiliation(s)
- Alexander Fort
- Diabetes Research Institute, University of Miami, Miami, FL 33136, USA
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31
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Abbah SA, Lu WW, Peng SL, Aladin DMK, Li ZY, Tam WK, Cheung KMC, Luk KDK, Zhou GQ. Extracellular matrix stability of primary mammalian chondrocytes and intervertebral disc cells cultured in alginate-based microbead hydrogels. Cell Transplant 2009; 17:1181-92. [PMID: 19181212 DOI: 10.3727/096368908787236648] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Three-dimensional alginate constructs are widely used as carrier systems for transplantable cells. In the present study, we evaluated the chondrogenic matrix stability of primary rat chondrocytes and intervertebral disc (IVD) cells cultured in three different alginate-based microbead matrices to determine the influence of microenvironment on the cellular and metabolic behaviors of chondrogenic cells confined in alginate microbeads. Cells entrapped in calcium, strontium, or barium ion gelled microbeads were monitored with the live/dead dual fluorescent cell viability assay kit and the 1,9-dimethylmethylene blue (DMB) assay designed to evaluate sulfated glycosaminoglycan (s-GAG) production. Expression of chondrogenic extracellular matrix (ECM) synthesis was further evaluated by semiquantitative RT-PCR of sox9, type II collagen, and aggrecan mRNAs. Results indicate that Ca and Sr alginate maintained significantly higher population of living cells compared to Ba alginate (p < 0.05). Production of s-GAG was similarly higher in Ca and Sr alginate microbead cultures compared to Ba alginate microbeads. Although there was no significant difference between strontium and calcium up to day 14 of culture, Sr alginate showed remarkably improved cellular and metabolic activities on long-term cultures, with chondrocytes expressing as much as 31% and 44% greater s-GAG compared to calcium and barium constructs, respectively, while IVD cells expressed 63% and 74% greater s-GAG compared to calcium and barium constructs, respectively, on day 28. These findings indicate that Sr alginate represent a significant improvement over Ca- and Ba alginate microbeads for the maintenance of chondrogenic phenotype of primary chondrocytes and IVD cells.
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Affiliation(s)
- S A Abbah
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong SAR, China
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32
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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: 8.1] [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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Foster JL, Williams G, Williams LJ, Tuch BE. Differentiation of Transplanted Microencapsulated Fetal Pancreatic Cells. Transplantation 2007; 83:1440-8. [PMID: 17565317 DOI: 10.1097/01.tp.0000264555.46417.7d] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Fetal beta cells are a potential form of cell therapy for type 1 diabetes. To protect transplanted cells from cellular immune attack, microencapsulation using barium alginate can be employed. Whether microencapsulated fetal pancreatic cells will differentiate as occurs with nonencapsulated fetal pancreatic cells is presently unknown. It is suggested that such differentiation would occur in encapsulated cells, similar to previous experiments conducted using encapsulated embryonic stem cells. METHODS Streptozotocin-induced diabetic severe combined immunodeficient mice were transplanted with 5,000 to 38,000 fetal pig islet-like cell clusters (ICCs) within barium alginate microcapsules of diameter 300, 600, or 1000 microm. Viability, insulin secretion, and content of encapsulated cells were measured prior to transplantation. Blood glucose levels (BGL) were measured twice weekly and porcine C-peptide monthly. Encapsulated cells were recovered from mice at 6 months posttransplantation for analysis. RESULTS Encapsulated cells became glucose responsive and normalized BGL within 13 to 68 days posttransplantation, with 5,000 to 10,000 ICCs required. Microcapsule diameter did not affect the time required to achieve normoglycemia. BGL remained normal for the 6-month duration of the experiments. After removal of grafts at 25 weeks posttransplantation, glucose stimulated insulin secretion of the explants was enhanced 96-fold, insulin content was enhanced 34-fold, and the percentage of insulin and glucagon positive cells increased 10-fold and threefold, respectively, from the time of transplantation. CONCLUSIONS This study demonstrates that fetal pancreatic cells differentiate and function normally when placed within barium alginate microcapsules and transplanted.
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Affiliation(s)
- Jayne L Foster
- Diabetes Transplant Unit, Prince of Wales Hospital, the University of New South Wales, Sydney, Australia
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Cheng SY, Constantinidis I, Sambanis A. Insulin secretion dynamics of free and alginate-encapsulated insulinoma cells. Cytotechnology 2006; 51:159-70. [PMID: 19002886 DOI: 10.1007/s10616-006-9025-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 09/15/2006] [Indexed: 10/23/2022] Open
Abstract
This study investigates the effect of alginate/poly-L: -lysine/alginate (APA) encapsulation on the insulin secretion dynamics exhibited by an encapsulated cell system. Experiments were performed with the aid of a home-built perfusion apparatus providing a 1 min temporal resolution. Insulin profiles were measured from: (i) murine insulinoma betaTC3 cells encapsulated in calcium alginate/poly-L: -lysine/alginate (APA) beads generated with high guluronic (G) or high mannuoric (M) content alginate, and (ii) murine insulinoma betaTC-tet cells encapsulated in high M APA beads and propagated in the presence and absence of tetracycline. Results show that encapsulation in APA beads did not affect the insulin secretion profile shortly post-encapsulation. However, remodeling of the beads due to cell proliferation affected the insulin secretion profiles; and inhibiting remodeling by suppressing cell growth preserved the secretion profile. The implications of these findings regarding the in vivo function of encapsulated insulin secreting cells are discussed.
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Affiliation(s)
- Shing-Yi Cheng
- Chemical & Biomolecular Engineering, Georgia Institute of Technology, 315 Ferst Drive, IBB Building, Room 1306, Atlanta, GA, 30332, USA
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Hanley S, Liu S, Lipsett M, Castellarin M, Rosenberg L, Tchervenkov J, Paraskevas S. Tumor necrosis factor-alpha production by human islets leads to postisolation cell death. Transplantation 2006; 82:813-8. [PMID: 17006329 DOI: 10.1097/01.tp.0000234787.05789.23] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Recent successes in islet transplantation highlight the importance of islet isolation by experienced centers and minimization of cell injury as crucial to the achievement of insulin independence. Islet injury may manifest as cell death by apoptosis, shorter graft survival, and the need for retransplantation. Although an inflammatory cytokine response at the graft site is known to inhibit engraftment, recent evidence indicates that islet cells may contribute to this response. METHODS Isolated human islets were cultured for up to one week in serum-free CMRL-1066 with 25 microM of tumor necrosis factor (TNF)alpha inhibitor RDP58. Gene expression was measured by reverse transcriptase polymerase chain reaction, apoptosis and TNFalpha secretion by enzyme-linked immunosorbent assay and enzyme-linked immunospot, and islet function by stimulated insulin secretion. RESULTS Isolation induced a twofold increase in TNFalpha expression between days one and three (P<0.05), while TNFalpha secretion peaked at day one. RDP58 reduced TNFalpha secretion by 70.6% (P<0.02), though TNFalpha gene expression was unaffected. RDP58 reduced the frequency of TNFalpha-secreting islets by 64.4% (P<0.05) and reduced apoptotic levels by 26.4% within 24 hr postisolation (P<0.05). The reduction in apoptosis was maintained throughout the week (P<0.01), while apoptosis increased in control cultures. Finally, RDP58-treated islets displayed increased insulin secretion in response to both elevated glucose (1915.0+/-396.6 vs. 825.3+/-261.1 mU/L, P<0.01) and secretagogues (2294.3+/-529.5 vs. 939.8+/-333.7 mU/L, P<0.02). CONCLUSIONS These data demonstrate that intraislet cytokine production should be considered as a factor leading to islet cell death postisolation and postengraftment, and strategies aimed at countering islet cytokine production represent a novel target for improving islet viability and function.
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Affiliation(s)
- Stephen Hanley
- Department of Surgery, McGill University, Montréal, Québec, Canada
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de Vos P, de Haan BJ, Kamps JAAM, Faas MM, Kitano T. Zeta‐potentials of alginate‐PLL capsules: A predictive measure for biocompatibility? J Biomed Mater Res A 2006; 80:813-9. [PMID: 17058213 DOI: 10.1002/jbm.a.30979] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Alginate-poly-L-lysine (PLL) microencapsulation of cells is a promising approach to prevent rejection in the absence of immunosuppression. Clinical application, however, is hampered by insufficient insight in factors influencing biocompatibility of the capsules. By now, it has been accepted that not only the chemical composition of the materials applied but also other factors contribute to bioincompatibility. The zeta-potential serves as a measure for the electrical charge of the surface and has been shown to be a predictive value for the interfacial reactions between the biomaterial and the surrounding tissue in other applications. In the present study, we have assessed the streaming potential of alginate-PLL capsules composed of either low-, intermediate-, or high-guluronic (G) alginate to calculate the zeta-potential. The zeta-potentials of the capsules were compared to the biological response against the capsules at 4 weeks after implantation in the rat. We show that high-G and low-G alginates provoke a more severe response in the rat than capsules prepared of intermediate-G alginate. This correlates with a higher zeta-potential of the high-G and low-G alginates and by a change in zeta-potential at lower pH. These lower pH-levels are common directly after implantation as the consequence of a host-response associated with mandatory surgery. Our results suggest that we should not only consider the capsule properties under physiological circumstances to explain bioincompatibility but also the capsule features during common pathophysiological situations.
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Affiliation(s)
- Paul de Vos
- Department of Pathology and Laboratory Medicine, Section of Medical Biology, Division of Immunoendocrinology, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
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Krol S, del Guerra S, Grupillo M, Diaspro A, Gliozzi A, Marchetti P. Multilayer nanoencapsulation. New approach for immune protection of human pancreatic islets. NANO LETTERS 2006; 6:1933-9. [PMID: 16968004 DOI: 10.1021/nl061049r] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Immune protection of artificial tissue by means of pancreatic islet microencapsulation is a very ambitious new approach to avoid life-long immune suppression. But the success in the utilization of the alginate-beads with incorporated islets is unfortunately limited. Some of the problems cannot be solved by a two-component system, so polymer encapsulation of the microbeads was tested to improve the properties. In the present paper a pure nanoencapsulation multilayer approach was tested in order to reduce the size of the capsule and possibly apply in the future a multilayer capsule with individual properties in each layer or region of the capsule. Different polycations were attached in a self-assembly process. The advantage in using the surface charge of islets as binding site for the polyions is the guarantee of complete coverage after the second layer. Release of insulin was determined to characterize the function of the islets after encapsulation as well as the permeability of the capsule. Fluorescence microscopy was used to visualize the polyelectrolyte layers. Finally by means of an immune assay, the protection capability of the capsule was proved. In these first measurements the encapsulation with a multilayer nanocapsule was shown to be a possible alternative to the more space-consuming and random islet-trapping microencapsulation.
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Affiliation(s)
- Silke Krol
- Department of Physics, University of Genoa, via Dodecaneso 33, 16146 Genoa, Italy.
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de Vos P, Faas MM, Strand B, Calafiore R. Alginate-based microcapsules for immunoisolation of pancreatic islets. Biomaterials 2006; 27:5603-17. [PMID: 16879864 DOI: 10.1016/j.biomaterials.2006.07.010] [Citation(s) in RCA: 350] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 07/11/2006] [Indexed: 01/12/2023]
Abstract
Transplantation of microencapsulated cells is proposed as a therapy for the treatment of a wide variety of diseases since it allows for transplantation of endocrine cells in the absence of undesired immunosuppression. The technology is based on the principle that foreign cells are protected from the host immune system by an artificial membrane. In spite of the simplicity of the concept, progress in the field of immunoisolation has been hampered for many years due to biocompatibility issues. During the last years important advances have been made in the knowledge of the characteristics and requirements capsules have to meet in order to provide optimal biocompatibility and survival of the enveloped tissue. Novel insight shows that not only the capsules material but also the enveloped cells should be hold responsible for loss of a significant portion of the immunoisolated cells and, thus, failure of the grafts on the long term. Microcapsules without cells can be produced as such that they remain free of any significant foreign body response for prolonged periods of time in both experimental animals and humans. New approaches in which newly discovered inflammatory responses are silenced bring the technology of transplantation of immunoisolated cells close to clinical application.
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Affiliation(s)
- Paul de Vos
- Department of Pathology and Laboratory Medicine, Division of Medical Biology, University Hospital of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
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Robitaille R, Dusseault J, Henley N, Desbiens K, Labrecque N, Hallé JP. Inflammatory response to peritoneal implantation of alginate–poly-l-lysine microcapsules. Biomaterials 2005; 26:4119-27. [PMID: 15664639 DOI: 10.1016/j.biomaterials.2004.10.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 10/19/2004] [Indexed: 11/16/2022]
Abstract
A thorough understanding of the mechanisms involved in the host reaction to alginate-poly-L-lysine microcapsules (HRM) is important to design methods for the evaluation, selection, and development of biocompatible biomaterials and microcapsules or treatments to control this reaction. The objective of this study was to identify those immune cells and cytokines involved in the pathogenesis of the HRM. The total and differential cell counts were evaluated, and the mRNA expression of TNF-alpha, IL-1beta, IL-6 and TGF-beta1 was measured in peritoneal washings at 3, 17, 48, 96 and 168 h after saline or microcapsule injections. Neutrophil number and IL-1beta and IL-6 m-RNA expression presented an early transient increase, with no differences between saline and microcapsule injections, suggesting a reaction to the procedure. Macrophages, lymphocytes and TNF-alpha were significantly more activated over a longer period of time, after microcapsule implantation than saline injection. They are likely involved in transforming the reaction into a chronic inflammatory process. TGF-beta1 and IL-1beta presented a late (day 7) significant increase after microcapsule but not saline injections. They are likely involved in transforming the reaction into a fibrogenic process. These results suggest that macrophages, lymphocytes, TNF-alpha, IL-1beta and TGF-beta1 play a role in the pathogenesis of the HRM.
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Affiliation(s)
- Robert Robitaille
- Université de Montréal, Centre de Recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, 5415 boulevard de l'Assomption, Montréal, Qué., Canada H1T 2M4
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Ponce S, Orive G, Gascón AR, Hernández RM, Pedraz JL. Microcapsules prepared with different biomaterials to immobilize GDNF secreting 3T3 fibroblasts. Int J Pharm 2005; 293:1-10. [PMID: 15778039 DOI: 10.1016/j.ijpharm.2004.10.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Revised: 07/20/2004] [Accepted: 10/29/2004] [Indexed: 11/16/2022]
Abstract
Cell microencapsulation represents a promising tool for the treatment of many central nervous system (CNS) diseases such as Parkinson's disease. In this technology, cells are surrounded by a semipermeable membrane which protects them from mechanical stress and isolates them from host's immune response. However, if the future clinical application of this strategy is wanted, many challenges remain including the improvement of the mechanical resistance of the microcapsules and the optimization of the intracapsular microenvironment conditions. In this way, the selection of the matrix is essential because the morphological and the physiological behavior of the cells depend on the interactions between the matrix and the enclosed cells. Assuming these considerations, three types of microcapsules elaborated with four different polymers: alginate, cellulose sulfate, agarose and pectin have been fabricated and compared in order to evaluate some key properties such as morphology, size and mechanical stability. Furthermore, GDNF secreting Fischer rat 3T3 fibroblasts were immobilized in each type of capsule and the viability and neurotrophic factor release was determinated. Results showed that the alginate and pectin microcapsules were the most resistant devices, maintaining an adequate microenvironment for the enclosed cells. In contrast, cells entrapped in alginate-cellulose sulfate matrices presented the lowest mechanical resistance, cell viability and GDNF production.
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Affiliation(s)
- S Ponce
- Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country, Vitoria-Gasteiz, Spain
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Juste S, Lessard M, Henley N, Ménard M, Hallé JP. Effect of poly-L-lysine coating on macrophage activation by alginate-based microcapsules: Assessment using a newin vitromethod. J Biomed Mater Res A 2005; 72:389-98. [PMID: 15669081 DOI: 10.1002/jbm.a.30254] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The characteristics of the microcapsule surface, which interacts directly with the host macrophages, may have a role in the biocompatibility of alginate-poly-L-lysine (PLL)-alginate (APA) microcapsule. The objectives of the study were: 1) to develop and validate a simple, rapid, and sensitive in vitro method for assessing microcapsule biocompatibility, based on microcapsule coincubation with macrophages and measurement, by reverse transcriptase-polymerase chain reaction, of cytokine mRNA expression, and 2) to evaluate the effect of alginate purification and PLL coating on macrophage activation. The mRNA expression of tumor necrosis factor-alpha and interleukin-1beta was significantly higher when macrophages were coincubated with beads made with nonpurified compared with purified alginate (p<0.01, p<0.05, respectively) and negative control (p<0.001) or with APA microcapsules compared with non-PLL-coated alginate beads and negative control (p<0.001). The mRNA expression of interleukin-6 differed significantly only when APA microcapsules were compared with a negative control (p<0.05). These results confirm that alginate purification improves microcapsule biocompatibility, and suggest that PLL is not completely covered and/or neutralized by the second alginate incubation and thus has a role in the host macrophage activation. The assay is sensitive to both alginate contaminants and microcapsule surface characteristics and may be a useful tool for the development of biocompatible microcapsules.
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Affiliation(s)
- Sandy Juste
- Centre de Recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, 5415, boulevard de l'Assomption, Montréal, Québec, H1T 2M4, Canada
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