1
|
Cui W, Khan KM, Ma X, Chen G, Desai CS. Human Amniotic Epithelial Cells and Human Amniotic Membrane as a Vehicle for Islet Cell Transplantation. Transplant Proc 2020; 52:982-986. [DOI: 10.1016/j.transproceed.2020.01.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/19/2019] [Accepted: 01/10/2020] [Indexed: 01/06/2023]
|
2
|
White AM, Shamul JG, Xu J, Stewart S, Bromberg JS, He X. Engineering Strategies to Improve Islet Transplantation for Type 1 Diabetes Therapy. ACS Biomater Sci Eng 2019; 6:2543-2562. [PMID: 33299929 DOI: 10.1021/acsbiomaterials.9b01406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes is an autoimmune disease in which the immune system attacks insulin-producing beta cells of pancreatic islets. Type 1 diabetes can be treated with islet transplantation; however, patients must be administered immunosuppressants to prevent immune rejection of the transplanted islets if they are not autologous or not engineered with immune protection/isolation. To overcome biological barriers of islet transplantation, encapsulation strategies have been developed and robustly investigated. While islet encapsulation can prevent the need for immunosuppressants, these approaches have not shown much success in clinical trials due to a lack of long-term insulin production. Multiple engineering strategies have been used to improve encapsulation and post-transplantation islet survival. In addition, more efficient islet cryopreservation methods have been designed to facilitate the scaling-up of islet transplantation. Other islet sources have been identified including porcine islets and stem cell-derived islet-like aggregates. Overall, islet-laden capsule transplantation has greatly improved over the past 30 years and is moving towards becoming a clinically feasible treatment for type 1 diabetes.
Collapse
Affiliation(s)
- Alisa M White
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - James G Shamul
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Jiangsheng Xu
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Samantha Stewart
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Jonathan S Bromberg
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD 21201.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201.,Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD 21201
| | - Xiaoming He
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD 21201.,Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, MD 20742, USA, Baltimore, MD 21201, USA
| |
Collapse
|
3
|
Bansal A, D'Sa S, D'Souza MJ. Biofabrication of microcapsules encapsulating beta-TC-6 cells via scalable device and in-vivo evaluation in type 1 diabetic mice. Int J Pharm 2019; 572:118830. [PMID: 31715349 DOI: 10.1016/j.ijpharm.2019.118830] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/21/2019] [Accepted: 10/26/2019] [Indexed: 02/08/2023]
Abstract
Type 1 diabetes mellitus (T1DM) is a disease characterized by lack of pancreatic islet function. Whole tissue transplantation appears to be a viable alternative in the management of T1DM. This study aims at the fabrication and evaluation of alginate-chitosan microcapsules encapsulating insulin-secreting beta-TC-6 cells using an automated spraying nozzle. Uniform spherical microcapsules (250-350 µm) encapsulated with beta-TC-6 cells were fabricated in large quantities in a short span of time. Microencapsulated beta-TC-6 cells were transplanted intraperitoneally into streptozotocin (STZ) induced diabetic mice and monitored for immune tolerance and decrease in blood glucose levels. Mice that received microencapsulated beta-TC-6 cells maintained normoglycemia for 35 ± 5 days before rejection. However, the group that received naked beta-TC-6 cells rejected the cells within 1-2 days, unable to control elevated blood glucose levels. They also exhibited high immune reactions, as evidenced by elevated levels of CD8+ and CD62L T cells. CD4+ T cells that mediated a Th2 response (humoral response) were predominant in microencapsulated beta-TC-6 cells and cells only group as evidenced by elevated levels of CD45R. Our findings from the in-vivo study demonstrated that transplantation of microencapsulated beta-TC-6 cells can be a viable alternative in the management of T1DM with acceptable immune response.
Collapse
Affiliation(s)
- Amit Bansal
- Center for Drug Delivery Research, Vaccine Nanotechnology Laboratory, Mercer University, College of Pharmacy, Atlanta, GA 30341, USA.
| | - Sucheta D'Sa
- Center for Drug Delivery Research, Vaccine Nanotechnology Laboratory, Mercer University, College of Pharmacy, Atlanta, GA 30341, USA
| | - Martin J D'Souza
- Center for Drug Delivery Research, Vaccine Nanotechnology Laboratory, Mercer University, College of Pharmacy, Atlanta, GA 30341, USA
| |
Collapse
|
4
|
Abstract
PURPOSE OF REVIEW Pancreatic islet cell transplantation is currently the only curative cell therapy for type 1 diabetes mellitus. However, its potential to treat many more patients is limited by several challenges. The emergence of 3D bioprinting technology from recent advances in 3D printing, biomaterials, and cell biology has provided the means to overcome these challenges. RECENT FINDINGS 3D bioprinting allows for the precise fabrication of complex 3D architectures containing spatially distributed cells, biomaterials (bioink), and bioactive factors. Different strategies to capitalize on this ability have been investigated for the 3D bioprinting of pancreatic islets. In particular, with co-axial bioprinting technology, the co-printability of islets with supporting cells such as endothelial progenitor cells and regulatory T cells, which have been shown to accelerate revascularization of islets and improve the outcome of various transplantations, respectively, has been achieved. 3D bioprinting of islets for generation of an artificial pancreas is a newly emerging field of study with a vast potential to improve islet transplantation.
Collapse
Affiliation(s)
- Juewan Kim
- Department of Molecular & Cellular Biology, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Kyungwon Kang
- Discipline of Medicine, School of Medicine, The University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Christopher J Drogemuller
- Discipline of Medicine, School of Medicine, The University of Adelaide, Adelaide, South Australia, 5000, Australia
- Central Northern Adelaide Renal and Transplantation Service (CNARTS), The Royal Adelaide Hospital, Adelaide, South Australia, 5000, Australia
| | - Gordon G Wallace
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterial Science, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - P Toby Coates
- Discipline of Medicine, School of Medicine, The University of Adelaide, Adelaide, South Australia, 5000, Australia.
- Central Northern Adelaide Renal and Transplantation Service (CNARTS), The Royal Adelaide Hospital, Adelaide, South Australia, 5000, Australia.
| |
Collapse
|
5
|
Barati G, Nadri S, Hajian R, Rahmani A, Mostafavi H, Mortazavi Y, Taromchi AH. Differentiation of microfluidic‐encapsulated trabecular meshwork mesenchymal stem cells into insulin producing cells and their impact on diabetic rats. J Cell Physiol 2018; 234:6801-6809. [DOI: 10.1002/jcp.27426] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 08/22/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Ghasem Barati
- Department of Medical Biotechnology and Nanotechnology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
| | - Samad Nadri
- Department of Medical Biotechnology and Nanotechnology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
- Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences Zanjan Iran
- Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences Zanjan Iran
| | - Ramin Hajian
- Novel Fluidic Systems Pioneers Co., Innovation & Entrepreneurship Center of Amirkabir University of Technology Tehran Iran
| | - Ali Rahmani
- Department of Medical Biotechnology and Nanotechnology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
| | - Hossein Mostafavi
- Department of Physiology and Pharmacology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
| | - Yousef Mortazavi
- Department of Medical Biotechnology and Nanotechnology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
- Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences Zanjan Iran
| | - Amir Hossein Taromchi
- Department of Medical Biotechnology and Nanotechnology School of Medicine, Zanjan University of Medical Sciences Zanjan Iran
| |
Collapse
|
6
|
Neuro-differentiated Ntera2 cancer stem cells encapsulated in alginate beads: First evidence of biological functionality. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 81:32-38. [DOI: 10.1016/j.msec.2017.07.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/07/2017] [Accepted: 07/19/2017] [Indexed: 12/29/2022]
|
7
|
Pathak S, Regmi S, Gupta B, Pham TT, Yong CS, Kim JO, Yook S, Kim JR, Park MH, Bae YK, Jeong JH. Engineered islet cell clusters transplanted into subcutaneous space are superior to pancreatic islets in diabetes. FASEB J 2017; 31:5111-5121. [PMID: 28754712 DOI: 10.1096/fj.201700490r] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/17/2017] [Indexed: 02/01/2023]
Abstract
An alternative route for pancreatic islet transplantation is the subcutaneous space; however, inadequate vascularization in the subcutaneous space limits the availability of oxygen and nutrients to the subcutaneously transplanted islets, which leads to the development of a necrotic core in the islets, thereby causing islet dysfunction. Thus, we aimed to prevent the early apoptosis of pancreatic islets after transplantation into subcutaneous space by preparing islet clusters of appropriate size. We prepared fully functional islet cell clusters (ICCs) by using the hanging-drop technique. We optimized the size of ICCs on the basis of viability and functionality after culture in an hypoxic environment. We transplanted ICCs into the subcutaneous space of diabetic mice and evaluated the viability of the islets at the transplantation site. In an hypoxic environment, ICCs exhibited improved viability and functionality compared with control islets. ICCs, upon transplantation into the hypoxic subcutaneous space of diabetic mice, showed better glycemic control compared with control islets. Live/dead imaging of the islets after retrieval from the transplanted area revealed significantly reduced apoptosis in ICCs. Transplantation of ICCs may be an attractive strategy to prevent islet cell apoptosis that results from nonimmune-mediated physiologic stress at the transplantation site.-Pathak, S., Regmi, S., Gupta, B., Pham, T. T., Yong, C. S., Kim, J. O., Yook, S., Kim, J.-R., Park, M. H., Bae, Y. K., Jeong, J.-H. Engineered islet cell clusters transplanted into subcutaneous space are superior to pancreatic islets in diabetes.
Collapse
Affiliation(s)
- Shiva Pathak
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Shobha Regmi
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Biki Gupta
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Tung Thanh Pham
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Chul Soon Yong
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Jong Oh Kim
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea
| | - Simmyung Yook
- College of Pharmacy, Keimyung University, Daegu, South Korea
| | - Jae-Ryong Kim
- Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu, Republic of Korea.,Smart-Aging Convergence Research Center, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - Min Hui Park
- Department of Pathology, College of Medicine, Yeungnam University, Daegu, South Korea
| | - Young Kyung Bae
- Department of Pathology, College of Medicine, Yeungnam University, Daegu, South Korea
| | - Jee-Heon Jeong
- College of Pharmacy, Yeungnam University, Gyeongsan, South Korea;
| |
Collapse
|
8
|
Nikravesh N, Cox SC, Birdi G, Williams RL, Grover LM. Calcium pre-conditioning substitution enhances viability and glucose sensitivity of pancreatic beta-cells encapsulated using polyelectrolyte multilayer coating method. Sci Rep 2017; 7:43171. [PMID: 28240241 PMCID: PMC5327385 DOI: 10.1038/srep43171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/08/2017] [Indexed: 12/13/2022] Open
Abstract
Type I diabetics are dependent on daily insulin injections. A therapy capable of immunoisolating pancreatic beta-cells and providing normoglycaemia is an alternative since it would avoid the late complications associated with insulin use. Here, 3D-concave agarose micro-wells were used to culture robust pancreatic MIN-6 cell spheroids within 24 hours that were shown to exhibit cell-cell contact and uniform size (201 ± 2 μm). A polyelectrolyte multilayer (PEM) approach using alginate and poly-l-lysine was employed to coat cell spheroids. In comparison to conventional PEM, use of a novel Ca2+ pre-coating step enhanced beta-cells viability (89 ± 6%) and metabolic activity since it reduced the toxic effect of the cationic polymer. Pre-coating was achieved by treating MIN-6 spheroids with calcium chloride, which enabled the adhesion of anionic polymer to the cells surface. Pre-coated cells coated with four bilayers of polymers were successfully immunoisolated from FITC-mouse antibody and pro-inflammatory cytokines. Novel PEM coated cells were shown to secret significantly (P < 0.05) different amounts of insulin in response to changes in glucose concentration (2 vs. 20 mM). This work presents a 3D culture model and novel PEM coating procedure that enhances viability, maintains functionality and immunoisolates beta-cells, which is a promising step towards an alternative therapy to insulin.
Collapse
Affiliation(s)
- Niusha Nikravesh
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Sophie C Cox
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Gurpreet Birdi
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard L Williams
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Liam M Grover
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| |
Collapse
|
9
|
Pathak S, Regmi S, Gupta B, Poudel BK, Pham TT, Kim JR, Park PH, Yong CS, Kim JO, Bae YK, Kim SK, Jeong JH. Hybrid Congregation of Islet Single Cells and Curcumin-Loaded Polymeric Microspheres as an Interventional Strategy to Overcome Apoptosis Associated with Pancreatic Islets Transplantation. ACS APPLIED MATERIALS & INTERFACES 2016; 8:25702-25713. [PMID: 27666317 DOI: 10.1021/acsami.6b07897] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hypoxic or near-anoxic conditions that occur in the core of transplanted islets induce necrosis and apoptosis during the early stages after transplantation, primarily due to loss of vascularization during the isolation process. Moreover, secretion of various cytokines from pancreatic islets is detrimental to the viability of islet cells in vitro. In this study, we aimed to protect pancreatic islet cells against apoptosis by establishing a method for in situ delivery of curcumin to the pancreatic islets. Self-assembled heterospheroids composed of pancreatic islet cells and curcumin-loaded polymeric microspheres were prepared by the three-dimensional cell culture technique. Release of curcumin in the microenvironment of pancreatic islets promoted survival of the islets. In hypoxic culture conditions, which mimic the in vivo conditions after transplantation, viability of the islets was significantly improved, as indicated by a decreased expression of pro-apoptotic protein and an increased expression of anti-apoptotic protein. Additionally, oxidative stress-induced cell death was suppressed. Thus, unlike co-transplantation of pancreatic islets and free microspheres, which provided a wide distribution of microspheres throughout the transplanted area, the heterospheroid transplantation resulted in colocalization of pancreatic islet cells and microspheres, thereby exerting beneficial effects on the cells.
Collapse
Affiliation(s)
- Shiva Pathak
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Shobha Regmi
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Biki Gupta
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Bijay K Poudel
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Tung Thanh Pham
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Jae-Ryong Kim
- Department of Biochemistry and Molecular Biology and Smart-Aging Convergence Research Center, College of Medicine, Yeungnam University , Daegu 42415, Republic of Korea
| | - Pil-Hoon Park
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Chul Soon Yong
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Jong Oh Kim
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Young Kyung Bae
- Department of Pathology, Yeungnam University College of Medicine , Daegu 42415, Republic of Korea
| | - Sang Kyoon Kim
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF) , Daegu 41061, Republic of Korea
| | - Jee-Heon Jeong
- College of Pharmacy, Yeungnam University , Gyeongsan, Gyeongbuk 38541, Republic of Korea
| |
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Tse HM, Kozlovskaya V, Kharlampieva E, Hunter CS. Minireview: Directed Differentiation and Encapsulation of Islet β-Cells-Recent Advances and Future Considerations. Mol Endocrinol 2015; 29:1388-99. [PMID: 26340406 DOI: 10.1210/me.2015-1085] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus has rapidly become a 21st century epidemic with the promise to create vast economic and health burdens, if left unchecked. The 2 major forms of diabetes arise from unique causes, with outcomes being an absolute (type 1) or relative (type 2) loss of functional pancreatic islet β-cell mass. Currently, patients rely on exogenous insulin and/or other pharmacologies that restore glucose homeostasis. Although these therapies have prolonged countless lives over the decades, the striking increases in both type 1 and type 2 diabetic diagnoses worldwide suggest a need for improved treatments. To this end, islet biologists are developing cell-based therapies by which a patient's lost insulin-producing β-cell mass is replenished. Pancreatic or islet transplantation from cadaveric donors into diabetic patients has been successful, yet the functional islet demand far surpasses supply. Thus, the field has been striving toward transplantation of renewable in vitro-derived β-cells that can restore euglycemia. Challenges have been numerous, but progress over the past decade has generated much excitement. In this review we will summarize recent findings that have placed us closer than ever to β-cell replacement therapies. With the promise of cell-based diabetes therapies on the horizon, we will also provide an overview of cellular encapsulation technologies that will deliver critical protection of newly implanted cells.
Collapse
Affiliation(s)
- Hubert M Tse
- Department of Microbiology and the Comprehensive Diabetes Center (H.M.T.) and Departments of Chemistry (V.K., E.K.) and Medicine, Division of Endocrinology Diabetes and Metabolism, and Comprehensive Diabetes Center (C.S.H.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Veronika Kozlovskaya
- Department of Microbiology and the Comprehensive Diabetes Center (H.M.T.) and Departments of Chemistry (V.K., E.K.) and Medicine, Division of Endocrinology Diabetes and Metabolism, and Comprehensive Diabetes Center (C.S.H.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Eugenia Kharlampieva
- Department of Microbiology and the Comprehensive Diabetes Center (H.M.T.) and Departments of Chemistry (V.K., E.K.) and Medicine, Division of Endocrinology Diabetes and Metabolism, and Comprehensive Diabetes Center (C.S.H.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Chad S Hunter
- Department of Microbiology and the Comprehensive Diabetes Center (H.M.T.) and Departments of Chemistry (V.K., E.K.) and Medicine, Division of Endocrinology Diabetes and Metabolism, and Comprehensive Diabetes Center (C.S.H.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| |
Collapse
|
12
|
Krishnan R, Alexander M, Robles L, Foster CE, Lakey JRT. Islet and stem cell encapsulation for clinical transplantation. Rev Diabet Stud 2014; 11:84-101. [PMID: 25148368 DOI: 10.1900/rds.2014.11.84] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues.
Collapse
Affiliation(s)
- Rahul Krishnan
- Department of Surgery, University of California Irvine, Orange, CA 92868, USA
| | - Michael Alexander
- Department of Surgery, University of California Irvine, Orange, CA 92868, USA
| | - Lourdes Robles
- Department of Surgery, University of California Irvine, Orange, CA 92868, USA
| | - Clarence E Foster
- Department of Surgery, University of California Irvine, Orange, CA 92868, USA
| | - Jonathan R T Lakey
- Department of Surgery, University of California Irvine, Orange, CA 92868, USA
| |
Collapse
|
13
|
Kozlovskaya V, Zavgorodnya O, Chen Y, Ellis K, Tse HM, Cui W, Thompson JA, Kharlampieva E. Ultrathin polymeric coatings based on hydrogen-bonded polyphenol for protection of pancreatic islet cells. ADVANCED FUNCTIONAL MATERIALS 2012; 22:3389-3398. [PMID: 23538331 PMCID: PMC3607452 DOI: 10.1002/adfm.201200138] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Though transplantation of pancreatic islet cells has emerged as a promising treatment for Type 1 diabetes its clinical application remains limited due to a number of limitations including both pathogenic innate and adaptive immune responses. We report here on a novel type of multifunctional cytoprotective material applied to coat living pancreatic islets. The coating utilizes hydrogen-bonded interactions of a natural polyphenol (tannic acid) with poly(N-vinylpyrrolidone) deposited on the islet surface via non-ionic layer-by-layer assembly. We demonstrate that the coating is conformal over the surface of mammalian islets including those derived from rat, non-human primate (NHP), and human. In contrast to unmodified controls, the coated islets maintain their viability and β-cell functionality for at least 96 hours in vitro. We also determine that the coating demonstrates immunomodulatory cytoprotective properties suppressing pro-inflammatory cytokine synthesis in stimulated bone marrow-derived macrophages and diabetogenic BDC-2.5 T cells. The coating material combines high chemical stability under physiologically relevant conditions with capability of suppressing cytokine synthesis, crucial parameters for prolonged islet integrity, viability, and function in vivo. Our study offers new opportunities in the area of advanced multifunctional materials to be used for a cell-based transplantation therapy.
Collapse
Affiliation(s)
- Veronika Kozlovskaya
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Oleksandra Zavgorodnya
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Yi Chen
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Kristin Ellis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Hubert M. Tse
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Wanxing Cui
- Department of Surgery, Division of Transplantation, the University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - J. Anthony Thompson
- Department of Surgery, Division of Transplantation, the University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| | - Eugenia Kharlampieva
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294 (USA)
| |
Collapse
|
14
|
Yao XC, Cui WX, Li YC, Zhang W, Lu RW, Thompson A, Amthor F, Wang XJ. Functional imaging of glucose-evoked rat islet activities using transient intrinsic optical signals. JOURNAL OF MODERN OPTICS 2012; 59:10.1080/09500340.2012.674564. [PMID: 24363496 PMCID: PMC3867949 DOI: 10.1080/09500340.2012.674564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We demonstrate intrinsic optical signal (IOS) imaging of intact rat islet, which consists of many endocrine cells working together. A near-infrared digital microscope was employed for optical monitoring of islet activities evoked by glucose stimulation. Dynamic NIR images revealed transient IOS responses in the islet activated by low-dose (2.75mM) and high-dose (5.5mM) glucose stimuli. Comparative experiments and quantitative analysis indicated that both glucose metabolism and calcium/insulin dynamics might contribute to the observed IOS responses. Further investigation of the IOS imaging technology may provide a high resolution method for ex vivo functional examination of the islet, which is important for advanced study of diabetes associated islet dysfunctions and for improved quality control of donor islets for transplantation.
Collapse
Affiliation(s)
- Xin-Cheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Corresponding author.
| | - Wan-Xing Cui
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yi-Chao Li
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Wei Zhang
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rong-Wen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Anthony Thompson
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Franklin Amthor
- Department of Psychology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Xu-Jing Wang
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- The Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| |
Collapse
|
15
|
Kahan BD. Forty years of publication of Transplantation Proceedings--the fourth decade: Globalization of the enterprise. Transplant Proc 2011; 43:3-29. [PMID: 21335147 DOI: 10.1016/j.transproceed.2010.12.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Barry D Kahan
- Division of Immunology and Organ Transplantation, The University of Texas-Health Science Center at Houston Medical School, Houston, Texas 77030, USA.
| |
Collapse
|
16
|
Cui W, Angsana J, Wen J, Chaikof EL. Liposomal Formulations of Thrombomodulin Increase Engraftment after Intraportal Islet Transplantation. Cell Transplant 2010; 19:1359-67. [DOI: 10.3727/096368910x513964] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Early destruction of donor islet grafts due to an instant blood-mediated inflammatory reaction (IBMIR) remains a major obstacle in islet transplantation. Thrombomodulin plays an important role in limiting coagulation and inflammatory events through a variety of effects. In this study, we investigated the ability of thrombomodulin (TM), when reconstituted as a liposomal formulation, to enhance early syngeneic islet engraftment by minimizing or abrogating the IBMIR. Administration of TM significantly improved early engraftment of syngeneic islets after intraportal transplantation in diabetic mice. In the absence of treatment, conversion to euglycemia was observed among 46.6% (7/15) of recipients. In contrast, administration of TM led to euglycemia in 93.3% (14/15) of recipients ( p = 0.0142). Recipients that received TM exhibited a lower incidence of primary nonfunction and better glucose control over a 30-day period after transplantation. Fibrin deposition ( p < 0.05), neutrophil infiltration ( p < 0.05), expression of TNF-α and IL-β mRNA ( p < 0.05), as well as NF-κB activity ( p < 0.05) were significantly reduced in the liver of islet recipients having been treated with liposomal TM. These data demonstrate that TM significantly improves early syngeneic islet engraftment through effects that target both coagulation and inflammatory pathways.
Collapse
Affiliation(s)
- Wanxing Cui
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Julianty Angsana
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, USA
| | - Jing Wen
- Department of Surgery, Emory University, Atlanta, GA, USA
| | - Elliot L. Chaikof
- Department of Surgery, Emory University, Atlanta, GA, USA
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| |
Collapse
|
17
|
Kizilel S, Scavone A, Liu X, Nothias JM, Ostrega D, Witkowski P, Millis M. Encapsulation of pancreatic islets within nano-thin functional polyethylene glycol coatings for enhanced insulin secretion. Tissue Eng Part A 2010; 16:2217-28. [PMID: 20163204 DOI: 10.1089/ten.tea.2009.0640] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Covalent attachment of polymers to cells and tissues could be used to solve a variety of problems associated with cellular therapies. Insulin-dependent diabetes mellitus is a disease resulting from the autoimmune destruction of the beta cells of the islets of Langerhans in the pancreas. Transplantation of islets into diabetic patients is an attractive form of treatment, provided that the islets could be protected from the host's immune system to prevent graft rejection, and smaller numbers of islets transplanted in smaller volumes could be sufficient to reverse diabetes. Therefore, a need exists to develop islet encapsulation strategies that minimize transplant volume. In this study, we demonstrate the formation of nano-thin, poly(ethylene glycol) (PEG)-rich functional conformal coatings on individual islets via layer-by-layer assembly technique. The surface of the islets is modified with biotin-PEG-N-hydroxysuccinimide (NHS), and the islets are further covered by streptavidin (SA) and biotin-PEG-peptide conjugates using the layer-by-layer method. An insulinotropic ligand, glucagon-like peptide-1 (GLP-1), is conjugated to biotin-PEG-NHS. The insulinotropic effect of GLP-1 is investigated through layer-by-layer encapsulation of islets using the biotin-PEG-GLP-1 conjugate. The effect of islet surface modification using the biotin-PEG-GLP-1 conjugate on insulin secretion in response to glucose challenge is compared via static incubation and dynamic perifusion assays. The results show that islets coated with the functional PEG conjugate are capable of secreting more insulin in response to high glucose levels compared to control islets. Finally, the presence of SA is confirmed by indirect fluorescent staining with SA-Cy3, and the presence of PEG-peptide on the surface of the islets after treatment with biotin-PEG-GLP-1 is confirmed by indirect fluorescent staining with biotin-PEG-fluorescein isothiocyanate (FITC) and separately with an anti-GLP-1 antibody. This work demonstrates the feasibility of treating pancreatic islets with reactive polymeric segments and provides the foundation for a novel means of potential immunoisolation. With this technique, it may be possible to encapsulate and/or modify islets before portal vein transplantation and reduce transplantation volume significantly, and promote islet viability and insulin secretion due to the presence of insulinotropic peptides on the islet surface. Layer-by-layer self-assembly of PEG-GLP-1 offers a unique approach to islet encapsulation to stimulate insulin secretion in response to high glucose levels.
Collapse
Affiliation(s)
- Seda Kizilel
- Department of Chemical and Biological Engineering, College of Engineering, Koç University, Istanbul, Turkey.
| | | | | | | | | | | | | |
Collapse
|
18
|
Calcium phosphate cement chamber as an immunoisolative device for bioartificial pancreas: in vitro and preliminary in vivo study. Pancreas 2010; 39:444-51. [PMID: 20084047 DOI: 10.1097/mpa.0b013e3181be2f95] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES This study examined a calcium phosphate cement (CPC) chamber as an immunoisolative device to facilitate the use of xenogeneic cell sources without immunosuppression for the bioartificial pancreas (BAP). METHODS Mouse insulinoma cells were encapsulated in agarose gel and then enclosed in a CPC chamber to create a BAP. Bioartificial pancreas were evaluated by cell viability, live-dead cell ratio, and cytokine-mediated cytotoxicity assay and implanted into the peritoneal cavity of diabetic rats. Nonfasting blood glucose and serum insulin levels were analyzed perioperatively; BAPs were also retrieved for histological examination. RESULTS Insulinoma cells enclosed in the CPC chamber had normal viability, cell survival, and insulin secretion that was even cultured in media with cytokines. The nonfasting blood glucose level of rats was decreased from 460 +/- 50 to 132 +/- 43 mg/dL and maintained euglycemia for 22 days; serum insulin level was increased from 0.34 +/- 0.11 to 1.43 +/- 0.30 microg/dL after operation. Histological examination revealed the fibrous tissue envelopment, and immune-related cells that competed for oxygen resulting in hypoxia could be attributed to the dysfunction of BAPs. CONCLUSIONS This study proved the feasibility for using a CPC chamber as an immunoisolative device for the BAP. An alternative implanted site should be considered to extend the functional longevity of BAPs in further study.
Collapse
|
19
|
Weber LM, Lopez CG, Anseth KS. Effects of PEG hydrogel crosslinking density on protein diffusion and encapsulated islet survival and function. J Biomed Mater Res A 2009; 90:720-9. [PMID: 18570315 DOI: 10.1002/jbm.a.32134] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The rational design of immunoprotective hydrogel barriers for transplanting insulin-producing cells requires an understanding of protein diffusion within the hydrogel network and how alterations to the network structure affect protein diffusion. Hydrogels of varying crosslinking density were formed via the chain polymerization of dimethacrylated PEG macromers of varying molecular weight, and the diffusion of six model proteins with molecular weights ranging from 5700 to 67,000 g/mol was observed in these hydrogel networks. Protein release profiles were used to estimate diffusion coefficients for each protein/gel system that exhibited Fickian diffusion. Diffusion coefficients were on the order of 10(-6)-10(-7) cm(2)/s, such that protein diffusion time scales (t(d) = L(2)/D) from 0.5-mm thick gels vary from 5 min to 24 h. Adult murine islets were encapsulated in PEG hydrogels of varying crosslinking density, and islet survival and insulin release was maintained after two weeks of culture in each gel condition. While the total insulin released during a 1 h glucose stimulation period was the same from islets in each sample, increasing hydrogel crosslinking density contributed to delays in insulin release from hydrogel samples within the 1 h stimulation period.
Collapse
Affiliation(s)
- Laney M Weber
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0424, USA
| | | | | |
Collapse
|
20
|
Williams SJ, Wang Q, Macgregor RR, Siahaan TJ, Stehno-Bittel L, Berkland C. Adhesion of pancreatic beta cells to biopolymer films. Biopolymers 2009; 91:676-85. [PMID: 19353639 DOI: 10.1002/bip.21196] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dramatic reversal of Type 1 diabetes in patients receiving pancreatic islet transplants continues to prompt vigorous research concerning the basic mechanisms underlying patient turnaround. At the most fundamental level, transplanted islets must maintain viability and function in vitro and in vivo and should be protected from host immune rejection. Our previous reports showed enhancement of islet viability and insulin secretion per tissue mass for small islets (<125 mum) as compared with large islets (>125 mum), thus, demonstrating the effect of enhancing the mass transport of islets (i.e. increasing tissue surface area to volume ratio). Here, we report the facile dispersion of rat islets into individual cells that are layered onto the surface of a biopolymer film towards the ultimate goal of improving mass transport in islet tissue. The tightly packed structure of intact islets was disrupted by incubating in calcium-free media resulting in fragmented islets, which were further dispersed into individual or small groups of cells by using a low concentration of papain. The dispersed cells were screened for adhesion to a range of biopolymers and the nature of cell adhesion was characterized for selected groups by quantifying adherent cells, measuring the surface area coverage of the cells, and immunolabeling cells for adhesion proteins interacting with selected biopolymers. Finally, beta cells in suspension were centrifuged to form controlled numbers of cell layers on films for future work determining the mass transport limitations in the adhered tissue constructs. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 676-685, 2009.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.
Collapse
Affiliation(s)
- S Janette Williams
- Department of Physical Therapy and Rehabilitation Science, The University of Kansas Medical Center, Kansas City, KS
| | | | | | | | | | | |
Collapse
|
21
|
|
22
|
Cui W, Wilson JT, Wen J, Angsana J, Qu Z, Haller CA, Chaikof EL. Thrombomodulin improves early outcomes after intraportal islet transplantation. Am J Transplant 2009; 9:1308-16. [PMID: 19459803 PMCID: PMC2759690 DOI: 10.1111/j.1600-6143.2009.02652.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Primary islet nonfunction due to an instant blood mediated inflammatory reaction (IBMIR) leads to an increase in donor islet mass required to achieve euglycemia. In the presence of thrombin, thrombomodulin generates activated protein C (APC), which limits procoagulant and proinflammatory responses. In this study, we postulated that liposomal formulations of thrombomodulin (lipo-TM), due to its propensity for preferential uptake in the liver, would enhance intraportal engraftment of allogeneic islets by inhibiting the IBMIR. Diabetic C57BL/6J mice underwent intraportal transplantation with B10.BR murine islets. In the absence of treatment, conversion to euglycemia was observed among 29% of mice receiving 250 allo-islets. In contrast, a single infusion of lipo-TM led to euglycemia in 83% of recipients (p = 0.0019). Fibrin deposition (p < 0.0001), neutrophil infiltration (p < 0.0001), as well as expression TNF-alpha and IL-beta (p < 0.03) were significantly reduced. Significantly, thrombotic responses mediated by human islets in contact with human blood were also reduced by this approach. Lipo-TM improves the engraftment of allogeneic islets through a reduction in local thrombotic and inflammatory processes. As an enzyme-based pharmacotherapeutic, this strategy offers the potential for local generation of APC at the site of islet infusion, during the initial period of elevated thrombin production.
Collapse
Affiliation(s)
- W. Cui
- Department of Surgery, Emory University, Atlanta, GA
| | - J. T. Wilson
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA
| | - J. Wen
- Department of Surgery, Emory University, Atlanta, GA
| | - J. Angsana
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA
| | - Z. Qu
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA
| | - C. A. Haller
- Department of Surgery, Emory University, Atlanta, GA
| | - E. L. Chaikof
- Department of Surgery, Emory University, Atlanta, GA,Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA,School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA,Corresponding author: Elliot L. Chaikof,
| |
Collapse
|
23
|
Wilson JT, Chaikof EL. Thrombosis and inflammation in intraportal islet transplantation: a review of pathophysiology and emerging therapeutics. J Diabetes Sci Technol 2008; 2:746-59. [PMID: 19885257 PMCID: PMC2769789 DOI: 10.1177/193229680800200502] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
With the inception of the Edmonton Protocol, intraportal islet transplantation (IPIT) has re-emerged as a promising cell-based therapy for type 1 diabetes. However, current clinical islet transplantation remains limited, in part, by the need to transplant islets from 2-4 donor organs, often through several separate infusions, to reverse diabetes in a single patient. Results from clinical islet transplantation and experimental animal models now indicate that the majority of transplanted islets are destroyed in the immediate post-transplant period, a process largely facilitated by deleterious inflammatory responses triggered by islet-derived procoagulant and proinflammatory mediators. Herein, mechanisms that underlie the pathophysiology of thrombosis and inflammation in IPIT are reviewed, and emerging approaches to improve islet engraftment through attenuation of inflammatory responses are discussed.
Collapse
Affiliation(s)
- John T. Wilson
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Elliot L. Chaikof
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
- Department of Surgery, Emory University School of Medicine, Atlanta, Georgia
| |
Collapse
|
24
|
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.
Collapse
|
25
|
Pereira T, Millar TJ, Chuck JA. Viability analysis of alginate encapsulated micro-organisms using fluorescent stains. J Microencapsul 2006; 22:787-92. [PMID: 16421088 DOI: 10.1080/02652040500273829] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The encapsulation of micro-organisms such as bacteria and fungi in biopolymers is currently being evaluated as delivery systems in many fields. Information about the viability and morphology of the organisms in the microparticle is often required to ascertain the longevity of the systems. A rapid method using fluorescent stains for microbial viability has been validated for organisms within alginate microparticles. Usually viability is assessed by dissolving the microparticles and cell culturing. This new method is advantageous for slow growing or filamentous organisms because these are not quickly or accurately enumerated by plate counts. In addition, the technique also allows the morphology of the organism to be monitored over time.
Collapse
Affiliation(s)
- Tanya Pereira
- School of Science, Food and Horticulture, University of Western Sydney, Parramatta Campus, Penrith South, NSW, Australia
| | | | | |
Collapse
|