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Abstract
The low regenerative potential of the human body hinders proper regeneration of dysfunctional or lost tissues and organs due to trauma, congenital defects, and diseases. Tissue or organ transplantation has hence been a major conventional option for replacing the diseased or dysfunctional body parts of the patients. In fact, a great number of patients on waiting lists would benefit tremendously if tissue and organs could be replaced with biomimetic spare parts on demand. Herein, regenerative medicine and advanced biomaterials strive to reach this distant goal. Tissue engineering aims to create new biological tissue or organ substitutes, and promote regeneration of damaged or diseased tissue and organs. This approach has been jointly evolving with the major advances in biomaterials, stem cells, and additive manufacturing technologies. In particular, three-dimensional (3D) bioprinting utilizes 3D printing to fabricate viable tissue-like structures (perhaps organs in the future) using bioinks composed of special hydrogels, cells, growth factors, and other bioactive contents. A third generation of multifunctional biomaterials could also show opportunities for building biomimetic scaffolds, upon which to regenerate stem cells in vivo. Besides, decellularization technology based on isolation of extracellular matrix of tissue and organs from their inhabiting cells is presented as an alternative to synthetic biomaterials. Today, the gained knowledge of functional microtissue engineering and biointerfaces, along with the remarkable advances in pluripotent stem cell technology, seems to be instrumental for the development of more realistic microphysiological 3D in vitro tissue models, which can be utilized for personalized disease modeling and drug development. This chapter will discuss the recent advances in the field of regenerative medicine and biomaterials, alongside challenges, limitations, and potentials of the current technologies.
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Affiliation(s)
- Şükran Şeker
- Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara, Turkey
| | - Ayşe Eser Elçin
- Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara, Turkey
| | - Yaşar Murat Elçin
- Ankara University Faculty of Science, Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara, Turkey.
- Biovalda Health Technologies, Inc., Ankara, Turkey.
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2
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MacDonald MJ, Ansari IUH, Riedemann AS, Stoker SW, Eickhoff JC, Chlebeck PJ, Fernandez LA, Longacre MJ. A Novel Intron-Encoded Neuropilin-1 Isoform in Pancreatic Islets Associated With Very Young Age of Onset of Type 1 Diabetes. Diabetes 2022; 71:2058-2063. [PMID: 35713886 DOI: 10.2337/db21-1070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/09/2022] [Indexed: 11/13/2022]
Abstract
Net synthesis of pancreatic β-cells peaks before 2 years of life. β-Cell mass is set within the first 5 years of life. In-frame translational readthrough of the NRP1 gene exon 9 into intron 9 generates a truncated neuropilin-1 protein lacking downstream sequence necessary for binding VEGF that stimulates β-cell replication. VEGF is critical for developing but not adult islet neogenesis. Herein we show that cells in human pancreatic islets containing the full-length neuropilin-1 possess insulin but cells that contain the truncated neuropilin-1 are devoid of insulin. Decreased insulin cells increases susceptibility to onset of type 1 diabetes at a younger age. We also show that the frequency of a genetic marker in NRP1 intron 9 is higher among patients with onset of type 1 diabetes before age 4 years (31.8%), including those with onset at 0.67-2.00 and 2-4 years, compared with that in patients with onset at 4-8 years, at 8-12 years, and after 16 years (16.1%) with frequency equal to that in subjects without diabetes (16.0%). Decreased insulin cells plus the genetic data are consistent with a low effect mechanism that alters the onset of type 1 diabetes to a very young age in some patients, thus supporting the endotype concept that type 1 diabetes is a heterogeneous disease.
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Affiliation(s)
- Michael J MacDonald
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Israr-Ul H Ansari
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Amy S Riedemann
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Scott W Stoker
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Jens C Eickhoff
- Department of Biostatistics & Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Peter J Chlebeck
- Division of Transplantation Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Luis A Fernandez
- Division of Transplantation Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Melissa J Longacre
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI
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3
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Minardi S, Guo M, Zhang X, Luo X. An elastin-based vasculogenic scaffold promotes marginal islet mass engraftment and function at an extrahepatic site. JOURNAL OF IMMUNOLOGY AND REGENERATIVE MEDICINE 2019; 3:1-12. [PMID: 31681866 PMCID: PMC6824601 DOI: 10.1016/j.regen.2018.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In islet transplantation, one of the major obstacles to optimal engraftment is the loss of islet natural vascularization and islet-specific extracellular matrix (ECM) during the islet isolation process. Thus, transplanted islets must re-establish nutritional and physical support through formation of new blood vessels and new ECM. To promote this critical process, we developed an elastin-based vasculogenic and ECM-promoting scaffold engineered for extrahepatic islet transplantation. The scaffold by design consisted of type I collagen (Coll) blended with 20wt% of elastin (E) shown to promote angiogenesis as well as de novo ECM deposition. The resulting "CollE" scaffolds h ad interconnected pores with a size distribution tailored to accommodate seeding of islets as well as growth of new blood vessels. In vitro, CollE scaffolds enabled prolonged culture of murine islets for up to one week while preserving their integrity, viability and function. In vivo, after only four weeks post-transplant of a marginal islet mass, CollE scaffolds demonstrated enhanced vascularization of the transplanted islets in the epididymal fat pad and promoted a prompt reversal of hyperglycemia in previously diabetic recipients. This outcome was comparable to that of kidney capsular (KC) islet transplantation, and superior to that of islets transplanted on the control collagen-only scaffolds (Coll). Crucial genes associated with angiogenesis (VEGFA, PDGFB, FGF1, and COL3A1) as well as de novo islet-specific matrix deposition (COL6A1, COL4A1, LAMA2 and FN1) were all significantly upregulated in islets on CollE scaffolds in comparison to those on Coll scaffolds. Finally, CollE scaffolds were also able to support human islet culture in vitro. In conclusion, CollE scaffolds have the potential to improve the clinical outcome of marginal islet transplantation at extrahepatic sites by promoting angiogenesis and islet-specific ECM deposition.
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Affiliation(s)
- Silvia Minardi
- Center for Kidney Research and Therapeutics, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Michelle Guo
- Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, United States
| | - Xiaomin Zhang
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Xunrong Luo
- Center for Kidney Research and Therapeutics, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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Ernst AU, Bowers DT, Wang LH, Shariati K, Plesser MD, Brown NK, Mehrabyan T, Ma M. Nanotechnology in cell replacement therapies for type 1 diabetes. Adv Drug Deliv Rev 2019; 139:116-138. [PMID: 30716349 PMCID: PMC6677642 DOI: 10.1016/j.addr.2019.01.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/17/2019] [Accepted: 01/28/2019] [Indexed: 12/12/2022]
Abstract
Islet transplantation is a promising long-term, compliance-free, complication-preventing treatment for type 1 diabetes. However, islet transplantation is currently limited to a narrow set of patients due to the shortage of donor islets and side effects from immunosuppression. Encapsulating cells in an immunoisolating membrane can allow for their transplantation without the need for immunosuppression. Alternatively, "open" systems may improve islet health and function by allowing vascular ingrowth at clinically attractive sites. Many processes that enable graft success in both approaches occur at the nanoscale level-in this review we thus consider nanotechnology in cell replacement therapies for type 1 diabetes. A variety of biomaterial-based strategies at the nanometer range have emerged to promote immune-isolation or modulation, proangiogenic, or insulinotropic effects. Additionally, coating islets with nano-thin polymer films has burgeoned as an islet protection modality. Materials approaches that utilize nanoscale features manipulate biology at the molecular scale, offering unique solutions to the enduring challenges of islet transplantation.
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Affiliation(s)
- Alexander U Ernst
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Daniel T Bowers
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Long-Hai Wang
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Kaavian Shariati
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Mitchell D Plesser
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Natalie K Brown
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Tigran Mehrabyan
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Minglin Ma
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
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3D-Models of Insulin-Producing β-Cells: from Primary Islet Cells to Stem Cell-Derived Islets. Stem Cell Rev Rep 2018; 14:177-188. [PMID: 29181780 DOI: 10.1007/s12015-017-9783-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is a need for physiologically relevant assay platforms to provide functionally relevant models of diabetes, to accelerate the discovery of new treatment options and boost developments in drug discovery. In this review, we compare several 3D-strategies that have been used to increase the functional relevance of ex vivo human primary pancreatic islets and developments into the generation of stem cell derived pancreatic beta-cells (β-cells). Special attention will be given to recent approaches combining the use of extracellular matrix (ECM) scaffolds with pancreatic molecular memory, which can be used to improve yield and functionality of in vitro stem cell-derived pancreatic models. The ultimate goal is to develop scalable cell-based platforms for diabetes research and drug screening. This article will critically assess key aspects related to in vitro pancreatic 3D-ECM models and highlight the most promising approaches for future research.
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Koç Demir A, Elçin AE, Elçin YM. Osteogenic differentiation of encapsulated rat mesenchymal stem cells inside a rotating microgravity bioreactor: in vitro and in vivo evaluation. Cytotechnology 2018; 70:1375-1388. [PMID: 29943233 PMCID: PMC6214859 DOI: 10.1007/s10616-018-0230-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/23/2018] [Indexed: 01/24/2023] Open
Abstract
The objective of this study is to evaluate the in vitro and in vivo osteogenic potential of rat bone marrow mesenchymal stem cells (BM-MSCs) using chitosan/hydroxyapatite (C/HAp) microbeads as encapsulation matrix under osteoinductive medium and dynamic culture conditions. The degradation characteristics of C/HAp microbeads were evaluated under in vitro and in vivo conditions for 180 days. BM-MSCs were encapsulated in C/HAp microbeads with > 85% viability, and were cultured in a slow turning lateral vessel-type rotating bioreactor simulating microgravity conditions for 28 days, under the effect of osteogenic inducers. MTT assay showed that the metabolic activity of encapsulated cells was preserved > 80% after a week. In vitro experiments confirmed that the encapsulated BM-MSCs differentiated into osteoblastic cells, formed bone-like tissue under osteogenic microgravity bioreactor conditions. Preliminary in vivo study indicated C/HAp microbeads containing BM-MSCs were able to repair the surgically-created small bone defects in the rat femur. BM-MSCs-C/HAp composite microbeads may have potential for modular bone regeneration.
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Affiliation(s)
- Aysel Koç Demir
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Faculty of Science and Stem Cell Institute, Ankara University, Degol Caddesi, Tandogan, 06100, Ankara, Turkey
| | - Ayşe Eser Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Faculty of Science and Stem Cell Institute, Ankara University, Degol Caddesi, Tandogan, 06100, Ankara, Turkey
| | - Yaşar Murat Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Faculty of Science and Stem Cell Institute, Ankara University, Degol Caddesi, Tandogan, 06100, Ankara, Turkey.
- Biovalda Health Technologies, Inc., Ankara, Turkey.
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Perez-Basterrechea M, Esteban MM, Vega JA, Obaya AJ. Tissue-engineering approaches in pancreatic islet transplantation. Biotechnol Bioeng 2018; 115:3009-3029. [PMID: 30144310 DOI: 10.1002/bit.26821] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/08/2018] [Accepted: 08/14/2018] [Indexed: 12/15/2022]
Abstract
Pancreatic islet transplantation is a promising alternative to whole-pancreas transplantation as a treatment of type 1 diabetes mellitus. This technique has been extensively developed during the past few years, with the main purpose of minimizing the complications arising from the standard protocols used in organ transplantation. By using a variety of strategies used in tissue engineering and regenerative medicine, pancreatic islets have been successfully introduced in host patients with different outcomes in terms of islet survival and functionality, as well as the desired normoglycemic control. Here, we describe and discuss those strategies to transplant islets together with different scaffolds, in combination with various cell types and diffusible factors, and always with the aim of reducing host immune response and achieving islet survival, regardless of the site of transplantation.
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Affiliation(s)
- Marcos Perez-Basterrechea
- Unidad de Terapia Celular y Medicina Regenerativa, Servicio de Hematología y Hemoterapia, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain.,Plataforma de Terapias Avanzadas, Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Manuel M Esteban
- Departamento de Biología Funcional, Universidad de Oviedo, Oviedo, Spain
| | - Jose A Vega
- Departamento de Morfología y Biología Celular, Universidad de Oviedo, Oviedo, Spain.,Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Alvaro J Obaya
- Departamento de Biología Funcional, Universidad de Oviedo, Oviedo, Spain
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Danggui Sini Decoction Protected Islet Endothelial Cell Survival from Hypoxic Damage via PI3K/Akt/eNOS Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:5421023. [PMID: 30108656 PMCID: PMC6077529 DOI: 10.1155/2018/5421023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 02/07/2023]
Abstract
Danggui Sini decoction (DSD) is a traditional Chinese decoction, which is wildly applied and showed to be effective in ameliorating ischemia-related symptoms. However, the mechanisms of DSD action in ischemic damage remain to be fully clarified. Pancreatic islet endothelial cells are pivotal constituent of islet microvasculature, with high vulnerability to hypoxic injuries. Here, using MST1 cell, a pancreatic islet endothelial cell-line, as a model, we investigated the effects of DSD on hypoxia-stimulated endothelial cell lesions and its underlying mechanisms. We found that DSD-Containing Serum (DSD-CS), collected from DSD-treated rats, could efficiently protect MST1 survival and proliferation from Cobalt chloride (CoCl2) induced damage, including cell viability, proliferation, and tube formation. Furthermore, DSD-CS restored the activity of PI3K/Akt/eNOS signaling inhibited by CoCl2 in MST1 cells. The protective effect of DSD-CS could be blocked by the specific PI3K/Akt/eNOS inhibitor LY294002, suggesting that DSD-CS protection of MST1 cell survival from hypoxia was mediated by PI3K/Akt/eNOS pathway. In conclusion, DSD treatment protected MST1 survival from hypoxic injuries via PI3K/Akt/eNOS pathway, indicating its role in protecting microvascular endothelial cells.
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9
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The Optimal Timing for Pancreatic Islet Transplantation into Subcutaneous Scaffolds Assessed by Multimodal Imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2017; 2017:5418495. [PMID: 29440984 PMCID: PMC5758856 DOI: 10.1155/2017/5418495] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/16/2017] [Accepted: 11/22/2017] [Indexed: 12/21/2022]
Abstract
Subcutaneously implanted polymeric scaffolds represent an alternative transplantation site for pancreatic islets (PIs) with the option of vascularisation enhancement by mesenchymal stem cells (MSC). Nevertheless, a proper timing of the transplantation steps is crucial. In this study, scaffolds supplemented with plastic rods were implanted into diabetic rats and two timing schemes for subsequent transplantation of bioluminescent PIs (4 or 7 days after rod removal) were examined by multimodal imaging. The cavities were left to heal spontaneously or with 10 million injected MSCs. Morphological and vascularisation changes were examined by MRI, while the localisation and viability of transplanted islets were monitored by bioluminescence imaging. The results show that PIs transplanted 4 days after rod removal showed the higher optical signal and vascularisation compared to transplantation after 7 days. MSCs slightly improved vascularisation of the graft but hindered therapeutic efficiency of PIs. Long-term glycaemia normalisation (4 months) was attained in 80% of animals. In summary, multimodal imaging confirmed the long-term survival and function of transplanted PIs in the devices. The best outcome was reached with PIs transplanted on day 4 after rod removal and therefore the suggested protocol holds a potential for further applications.
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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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12
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Durkut S, Elçin YM. Synthesis and characterization of thermosensitive poly(N-vinylcaprolactam)-g-collagen. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 45:1665-1674. [DOI: 10.1080/21691401.2016.1276925] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Serap Durkut
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Ankara, Turkey
| | - Yaşar Murat Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Ankara, Turkey
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13
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Koç A, Elçin AE, Elçin YM. Ectopic osteogenic tissue formation by MC3T3-E1 cell-laden chitosan/hydroxyapatite composite scaffold. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2015; 44:1440-7. [DOI: 10.3109/21691401.2015.1036998] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Aysel Koç
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Ankara, Turkey
| | - Ayşe Eser Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Ankara, Turkey
| | - Yaşar Murat Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science, and Ankara University Stem Cell Institute, Ankara, Turkey
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14
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Koç A, Finkenzeller G, Elçin AE, Stark GB, Elçin YM. Evaluation of adenoviral vascular endothelial growth factor-activated chitosan/hydroxyapatite scaffold for engineering vascularized bone tissue using human osteoblasts: In vitro and in vivo studies. J Biomater Appl 2014; 29:748-60. [PMID: 25062670 DOI: 10.1177/0885328214544769] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bone tissue is dependent on an efficient blood supply to ensure delivery of nutrients and oxygen. One method to acquire a vascular-engineered bone tissue could be the use of an angiogenic gene-activated scaffold. In the current study, porous chitosan/hydroxyapatite (C/HA) scaffolds were fabricated via freeze-drying with desired pore size, and then combined with the adenoviral vector encoding vascular endothelial growth factor and green fluorescence protein (Ad-VEGF). Human osteoblasts were cultured and seeded on characterized scaffolds. The attachment, proliferation, and differentiation of cells on gene-activated and unactivated C/HA scaffolds were evaluated in vitro and in vivo by histo- and immunohistochemistry. Findings confirmed that human osteoblasts cultured on gene-activated C/HA scaffold secreted vascular endothelial growth factor, besides maintaining its characteristic phenotype with specific extracellular matrix production. In vivo experiments indicated that scaffolds were tissue biocompatible, and that gene-activated scaffold provided a suitable environment for neovessel formation by recruiting host endothelial cells into the newly forming ectopic bone-like tissue. This study revealed that the Ad-VEGF-activated C/HA composite scaffold has potential for vascular bone regeneration applications.
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Affiliation(s)
- Aysel Koç
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science and Ankara University Stem Cell Institute, Ankara, Turkey
| | - Günter Finkenzeller
- Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany
| | - A Eser Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science and Ankara University Stem Cell Institute, Ankara, Turkey
| | - G Björn Stark
- Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany
| | - Y Murat Elçin
- Tissue Engineering, Biomaterials and Nanobiotechnology Laboratory, Ankara University Faculty of Science and Ankara University Stem Cell Institute, Ankara, Turkey
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Abstract
Hydrogels are swollen, crosslinked networks that have great potential for use in biomedicine. Their softness, biocompatibility and ability for rapid diffusion of molecules make them useful for drug delivery, cell culture, wound healing and sensing applications. The chemical functionality of the gels can be easily modified to provide signalling and growth factors for cell proliferation. To allow the ingress of large cells, either porosity of the substrate can be controlled, or the gel can be made biodegradable. One ultimate goal is the growth of entire organs in the laboratory for eventual transplantation. Gels can be used as drug-delivery vehicles, either as implantable depots, or as microgels in blood-based delivery systems. One expanding area is the use of gels as surgical aides to prevent bleeding, infection and post-operative complications.
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Pirlo RK, Wu P, Liu J, Ringeisen B. PLGA/hydrogel biopapers as a stackable substrate for printing HUVEC networks via BioLP. Biotechnol Bioeng 2011; 109:262-73. [PMID: 21830203 DOI: 10.1002/bit.23295] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/22/2011] [Accepted: 08/03/2011] [Indexed: 01/05/2023]
Abstract
Two major challenges in tissue engineering are mimicking the native cell-cell arrangements of tissues and maintaining viability of three-dimension (3D) tissues thicker than 300 µm. Cell printing and prevascularization of engineered tissues are promising approaches to meet these challenges. However, the printing technologies used in biofabrication must balance the competing parameters of resolution, speed, and volume, which limit the resolution of thicker 3D structures. We suggest that high-resolution conformal printing techniques can be used to print 2D patterns of vascular cells onto biopaper substrates which can then be stacked to form a thicker tissue construct. Towards this end we created 1 cm × 1 cm × 300 µm biopapers to be used as the transferable, stackable substrate for cell printing. 3.6% w/v poly-lactide-co-glycolide was dissolved in chloroform and poured into molds filled with NaCl crystals. The salt was removed with DI water and the scaffolds were dried and loaded with a Collagen Type I or Matrigel. SEM of the biopapers showed extensive porosity and gel loading throughout. Biological laser printing (BioLP) was used to deposit human umbilical vein endothelial cells (HUVEC) in a simple intersecting pattern to the surface of the biopapers. The cells differentiated and stretched to form networks preserving the printed pattern. In a separate experiment to demonstrate "stackability," individual biopapers were randomly seeded with HUVECs and cultured for 1 day. The mechanically stable and viable biopapers were then stacked and cultured for 4 days. Three-dimensional confocal microscopy showed cell infiltration and survival in the compound multilayer constructs. These results demonstrate the feasibility of stackable "biopapers" as a scaffold to build 3D vascularized tissues with a 2D cell-printing technique.
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Affiliation(s)
- Russell Kirk Pirlo
- National Research Council Research Associate, Washington, Districto of Columbia 20001, USA
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Janis AD, Johnson CC, Ernst DM, Brightman AO. Structural characteristics of small intestinal submucosa constructs dictate in vivo incorporation and angiogenic response. J Biomater Appl 2011; 26:1013-33. [PMID: 21273257 DOI: 10.1177/0885328210391688] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The rate of angiogenesis and cellular infiltration into degradable biomaterials determines scaffold persistence in vivo. The ability to tune the degradation properties of naturally derived biomaterials has been a popular goal in tissue engineering, yet has often depended on chemical crosslinking. Small intestinal submucosa (SIS) is a naturally derived, collagen-based, bioactive scaffold that has broad clinical success in many therapeutic applications. Two methods for producing multilayer, non-crosslinked SIS constructs were compared in vitro and in vivo. Traditional and cryo SEM, mercury intrusion porosimetry, and a novel enzymatic degradation assay determined that lyophilization produced an open, porous scaffold, in contrast to the collapsed, denser structure of SIS constructs produced using a vacuum press process. The angiogenic responses to lyophilized and vacuum-pressed SIS constructs were evaluated in vivo using a subcutaneous implant assay in mice. Explanted samples were compared after 7 and 21 days using fluorescence microangiography and light microscopy. Capacity of the implant neovasculature was also determined. These experiments revealed that the lyophilized SIS was infiltrated and vascularized more rapidly than the vacuum pressed. These data demonstrate the tunable incorporation of a non-crosslinked ECM-based biomaterial, which may have implications for the persistence of this degradable scaffold in tissue engineering.
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18
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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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19
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Rocuts F, Zhang X, Yan J, Yue Y, Thomas M, Bach FH, Czismadia E, Wang H. Bilirubin Promotes De Novo Generation of T Regulatory Cells. Cell Transplant 2010; 19:443-51. [DOI: 10.3727/096368909x484680] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have previously demonstrated that bilirubin administration to the recipient induces tolerance towards islet cell transplants across a complete MHC mismatch in a mouse model. Here we assess the mechanisms of such protection. Bilirubin treatment of recipients improved function of islet allografts by suppressing expressions of proinflammatory and proapoptotic genes in those islets and by increasing Foxp3+ T regulatory (Treg) cells at the site of transplanted islets at various days after transplantation. No prolongation of graft survival was observed in recipients treated with bilirubin when CD4+CD25+ T cells were predepleted from those recipients, indicating that Treg cells are necessary for the protective effect of bilirubin. Adoptive transfer of Treg cells from tolerant mice into Rag1-/- recipients resulted in long-term acceptance of skin allografts in an alloantigen-specific manner, suggesting that Treg cells are sufficient to induce tolerance. In addition, bilirubin treatment promoted de novo generation of Treg cells in Rag1-/- recipients. Thus, bilirubin treatment to the recipients prolongs islet allograft survival via a Treg-dependent manner in which CD4+CD25+ Treg cells are both necessary and sufficient for tolerance induction and graft acceptance. Bilirubin treatment promotes de novo generation of Treg cells that might account for the protective effects of bilirubin given to recipients.
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Affiliation(s)
- Fredy Rocuts
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Xinyu Zhang
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jun Yan
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Yinan Yue
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Michael Thomas
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Fritz H. Bach
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Eva Czismadia
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Hongjun Wang
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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20
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Hasan NM, Kendrick MA, Druckenbrod NR, Huelsmeyer MK, Warner TF, MacDonald MJ. Genetic association of the neuropilin-1 gene with type 1 diabetes in children: Neuropilin-1 expression in pancreatic islets. Diabetes Res Clin Pract 2010; 87:e29-32. [PMID: 20053475 DOI: 10.1016/j.diabres.2009.12.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 12/04/2009] [Accepted: 12/08/2009] [Indexed: 11/29/2022]
Abstract
Minor alleles of two SNPs in intron 9 of the NRP1 gene, which encodes neuropilin-1, were found to be associated with type 1 diabetes (T1D) in children. Neuropilin-1 peptides were confined to islets in human pancreas. This suggests neuropilins-1 could influence the development of some cases of T1D in children.
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Affiliation(s)
- Noaman M Hasan
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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21
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Kodama S, Kojima K, Furuta S, Chambers M, Paz AC, Vacanti CA. Engineering Functional Islets from Cultured Cells. Tissue Eng Part A 2009; 15:3321-9. [DOI: 10.1089/ten.tea.2008.0459] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Shohta Kodama
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
- Department of Regenerative Medicine & Transplantation, Faculty of Medicine, Fukuoka University, Fukuoka City, Japan
| | - Koji Kojima
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
| | - Shigeyuki Furuta
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
| | - Melody Chambers
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
| | - Ana C. Paz
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
| | - Charles A. Vacanti
- Tissue engineering and Regenerative Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
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22
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Spadaccio C, Chello M, Trombetta M, Rainer A, Toyoda Y, Genovese JA. Drug releasing systems in cardiovascular tissue engineering. J Cell Mol Med 2009; 13:422-39. [PMID: 19379142 PMCID: PMC3822506 DOI: 10.1111/j.1582-4934.2008.00532.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Heart disease and atherosclerosis are the leading causes of morbidity and mortality worldwide. The lack of suitable autologous grafts has produced a need for artificial grafts; however, current artificial grafts carry significant limitations, including thrombosis, infection, limited durability and the inability to grow. Tissue engineering of blood vessels, cardiovascular structures and whole organs is a promising approach for creating replacement tissues to repair congenital defects and/or diseased tissues. In an attempt to surmount the shortcomings of artificial grafts, tissue-engineered cardiovascular graft (TECVG), constructs obtained using cultured autologous vascular cells seeded onto a synthetic biodegradable polymer scaffold, have been developed. Autologous TECVGs have the potential advantages of growth, durability, resistance to infection, and freedom from problems of rejection, thrombogenicity and donor scarcity. Moreover polymers engrafted with growth factors, cytokines, drugs have been developed allowing drug-releasing systems capable of focused and localized delivery of molecules depending on the environmental requirements and the milieu in which the scaffold is placed. A broad range of applications for compound-releasing, tissue-engineered grafts have been suggested ranging from drug delivery to gene therapy. This review will describe advances in the development of drug-delivery systems for cardiovascular applications focusing on the manufacturing techniques and on the compounds delivered by these systems to date.
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Affiliation(s)
- Cristiano Spadaccio
- Cardiac and Molecular Biology Laboratory, Heart, Lung & Esophageal Surgery Institute University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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23
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Mahato RI. Gene expression and silencing for improved islet transplantation. J Control Release 2009; 140:262-7. [PMID: 19376168 DOI: 10.1016/j.jconrel.2009.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 04/10/2009] [Indexed: 12/26/2022]
Abstract
Islet transplantation has great potential as an effective means of treating type 1 diabetes. However, its successful application greatly depends on the rapid revascularization of islets and prevention from their apoptotic cell death. We co-expressed human vascular endothelial growth factor (hVEGF) and human interleukin-1 receptor antagonist (hIL-1Ra) after transduction of human islets with Adv-hVEGF-hIL-1Ra. Since hepatocyte growth factor (HGF) increases beta-cell proliferation and promotes revascularization of islets, we also constructed Adv-hHGF-hIL-1Ra. There was dose and time dependent expression of hVEGF and hIL-1Ra or hHGF and hIL-1Ra by islets, which led to decrease in caspase-3 activity and apoptosis induced by a cocktail of TNF-alpha, IL-1beta and IFN-gamma. Compared to non-treated islets, transduction of islets with these bipartite Adv vectors prior to transplantation under the kidney capsules of diabetic NOD-SCID mice reduced the blood glucose levels, and increased serum insulin and c-peptide levels. Immunohistochemical staining of the islet bearing kidney sections was positive for human insulin, growth factor (hVEGF or hHGF) and von Willebrand factor. Transduction with Adv-caspase-3-shRNA also prevented islets from cytokine induced apoptosis and improved islet transplantation. In conclusion, bipartite Adv vector efficiently co-expressed both growth factor and antiapoptotic genes or shRNA targeting pro-apoptotic genes, decreases apoptosis and improves the outcome of islet transplantation.
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Affiliation(s)
- Ram I Mahato
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN 38103, USA.
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24
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Rauch MF, Michaud M, Xu H, Madri JA, Lavik EB. Co-culture of primary neural progenitor and endothelial cells in a macroporous gel promotes stable vascular networks in vivo. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2009; 19:1469-85. [PMID: 18973724 DOI: 10.1163/156856208786140409] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Most tissues cannot survive without microvascular networks. In many cases, the host cannot vascularize implanted tissues, motivating the need for implantable vascular networks for tissue engineered grafts. However, engineering microvascular networks that are stable and functional for long times has proven challenging. The co-culture of neural progenitor cells with endothelial cells may lead to long term, functional microvascular networks. Ideally, these networks should be made from primary cells to avoid the potential safety concerns associated with immortalized or genetically-engineered cells. Thus, we have investigated and developed a paradigm for isolating and co-culturing primary rat endothelial cells and neural progenitor cells in biodegradable poly(ethylene glycol)/poly(L-lysine) macroporous hydrogels. The co-culture of these primary cells in the gels led to stabilization of vessels with no evidence of vessel regression even as far out as 6 weeks, the longest time point studied. Further more, the vessels contained host red blood cells, demonstrating they anastomosed with the host and were functional. Functional vessels were found throughout the implants, and no adverse effects such as clotting or thrombosis were observed. This work suggests that a co-culture of primary cells seeded in a macroporous hydrogel is a novel method to promote stable functional vascular networks which are critical for engineering complex tissues.
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25
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Kawazoe N, Xiaoting Lin, Tateishi T, Guoping Chen. Three-dimensional Cultures of Rat Pancreatic RIN-5F Cells in Porous PLGA-collagen Hybrid Scaffolds. J BIOACT COMPAT POL 2009. [DOI: 10.1177/0883911508099439] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Three-dimensional cultures of pancreatic islet cells in porous scaffolds or hydrogels have been constructed as a biohybrid artificial pancreas. A thin mesh of a PLGA-collagen hybrid was used to culture rat RIN-5F cells. The hybrid mesh was coated with laminin, fibronectin, vitronectin, type IV collagen, and poly(L-lysine) were evaluated and mesh without coating was used as a control. Cell adhered and proliferated on all of the coated and uncoated meshes. The cells formed spheroids in the uncoated, poly(L-lysine)-, fibronectin-, vitronectin-, and type IV collagen-coated hybrid meshes, while forming a layered structure in the laminin-coated hybrid mesh. Cell adhesion on the coated PLGA-collagen hybrid meshes was higher than that for the uncoated hybrid mesh. The laminin-coated hybrid mesh showed the greatest level of adhesion. The insulin secretion capacity of RIN-5F cells was at the same level for all coated and uncoated PLGA-collagen hybrid meshes and higher than that of cells cultured on cell culture plates. The 3D cultured PLGA-collagen hybrid meshes promoted insulin production capacity. Gene expression analysis showed that genes encoding insulin I, insulin II, and the pancreatic transcription factor PDX-1 (pancreas/duodenum homeobox 1) was expressed. These results indicate that the PLGA-collagen hybrid meshes support adhesion, proliferation, and differentiation of RIN-5F cells that allows culturing pancreatic islet cells on 3D constructs.
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Affiliation(s)
- Naoki Kawazoe
- Biomaterials Center, National Institute for Materials Science 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Xiaoting Lin
- Biomaterials Center, National Institute for Materials Science 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Tetsuya Tateishi
- Biomaterials Center, National Institute for Materials Science 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Guoping Chen
- Biomaterials Center, National Institute for Materials Science 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan,
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26
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Shrader CD, Bailey KM, Konat GW, Cilento EV, Reilly FD. Insulin enhances proliferation and viability of human umbilical vein endothelial cells. Arch Dermatol Res 2008; 301:159-66. [PMID: 19115062 DOI: 10.1007/s00403-008-0921-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 11/18/2008] [Accepted: 12/06/2008] [Indexed: 11/29/2022]
Abstract
This investigation is a follow-up to our previous in vivo studies revealing that rapid stretch increases tissue insulin in murine skin flaps, coincident with the up-regulation of key angiogenic effectors and enhanced vascularization. In the present study, we used human umbilical vein endothelial cells (HUVECs) as an in vitro model system to determine the role of insulin in the chemical signals regulating the processes of proliferation and viability (survival). MTT-based colorimetric methods demonstrated that insulin enhances proliferation and survival of HUVECs. Western blot analysis revealed that protein kinase B (pAkt [Thr(308)]) and vascular endothelial growth factor (VEGF) were the insulin-responsive intermediates in proliferating endothelial cells (ECs). In insulin-enhanced survival, both pAkt (Thr(308)) and pAkt (Ser(473)) were activated in HUVECs. However, no change in VEGF expression accompanied pAkt activation. The beneficial effects of insulin were abrogated by insulin receptor (IR)/insulin-like growth factor receptor (IGFR) or phosphoinositide-3 kinase (PI3-K) blockade, suggesting that insulin-induced EC proliferation and viability are mediated through pIR/pIGFR and PI3-K effectors. These data provide new insights into the beneficial effects of insulin on vascularization and tissue viability, providing a mechanistic link to the enhancement of healing in acutely stretched skin.
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Affiliation(s)
- Carl D Shrader
- Department of Neurobiology and Anatomy, School of Medicine, West Virginia University, Morgantown, WV 26506-9128, USA
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27
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Emin N, Koç A, Durkut S, Elçin AE, Elçin YM. Engineering of rat articular cartilage on porous sponges: effects of tgf-beta 1 and microgravity bioreactor culture. ACTA ACUST UNITED AC 2008; 36:123-37. [PMID: 18437589 DOI: 10.1080/10731190801932116] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The objective of this study was to develop an engineered rat hyaline cartilage by culturing articular chondrocytes on three-dimensional (3D) macroporous poly(DL-lactic-co-glycolic acid) (PLGA) sponges under chondrogenic induction and microgravity bioreactor conditions. Experimental groups consisted of 3D static and dynamic cultures, while a single cell monolayer (2D) served as the control. The effect of seeding conditions (static vs. dynamic) on cellularization of the scaffolds was investigated. MTT assay was used to evaluate the number of viable cells in each group at different time points. Formation of a hyaline-like cartilage was evaluated for up to 4 weeks in vitro. While 2D culture resulted in cell sheets with very poor matrix production, 3D culture was in the favor of tissue formation. A higher yield of cell attachment and spatially uniform cell distribution was achieved when dynamic seeding technique was used. Dynamic culture promoted cell growth and infiltration throughout the sponge structure and showed the formation of cartilage tissue, while chondrogenesis appeared attenuated more towards the outer region of the constructs in the static culture group. Medium supplemented with TGF-beta 1 (5 ng/ml) had a positive impact on proteoglycan production as confirmed by histochemical analyses with Alcian blue and Safranin-O stainings. Formation of hyaline-like tissue was demonstrated by immunohistochemistry performed with antibodies against type II collagen and aggrecan. SEM confirmed higher level of cellularization and cartilage tissue formation in bioreactor cultures induced by TGF-beta 1. The data suggest that PLGA sponge inside rotating bioreactor with chondrogenic medium provides an environment that mediates isolated rat chondrocytes to redifferentiate and form hyaline-like rat cartilage, in vitro.
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Affiliation(s)
- Nuray Emin
- Ankara University, Faculty of Science and Biotechnology Institute, Tissue Engineering and Biomaterials Laboratory, Ankara, Turkey
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28
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Shrader CD, Ressetar HG, Luo J, Cilento EV, Reilly FD. Acute stretch promotes endothelial cell proliferation in wounded healing mouse skin. Arch Dermatol Res 2008; 300:495-504. [PMID: 18330587 DOI: 10.1007/s00403-008-0836-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 01/04/2008] [Accepted: 01/28/2008] [Indexed: 01/15/2023]
Abstract
We have developed a novel in vivo model utilizing acute stretch to investigate endothelial cell proliferation as a marker of vascular growth in healing mouse skin. This study is a follow-up to ones revealing immediate stretch improves blood flow, decreases total tissue necrosis, and induces tissue insulin transcription. Dorsal distally based flaps of skin were stretched for 3 min using linear (skin hook) plus hemispherical load cycling (inflated subcutaneous silicone catheter). Unstretched, wounded skin along the back and sternum served as postoperative controls. Laser Doppler flowmetry demonstrated a threefold increase in flap perfusion at postoperative day 7. A stretch-induced sixfold increase in endothelial cell mitogenesis accompanied enhancements in blood flow and extracorporal wound healing over the sternum. Western blots revealed up-regulation/activation of insulin and mitogenic signaling intermediates in stretched skin. Activated insulin and insulin growth factor receptors (pIR/pIGFR), protein kinase B (Akt, pAkt), vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (flk-1) were among the identified stretch-responsive intermediates. These results indicate the benefits of acute stretch are mediated through enhanced vascularity as evidenced by endothelial cell mitogenesis and up-regulation/activation of insulin and key angiogenic effectors in dorsal distally based skin flaps.
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Affiliation(s)
- Carl D Shrader
- Department of Neurobiology and Anatomy, School of Medicine, West Virginia University, Morgantown, WV, 26506-9128, USA.
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29
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Luong E, Gerecht S. Stem cells and scaffolds for vascularizing engineered tissue constructs. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2008; 114:129-72. [PMID: 19082932 DOI: 10.1007/10_2008_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The clinical impact of tissue engineering depends upon our ability to direct cells to form tissues with characteristic structural and mechanical properties from the molecular level up to organized tissue. Induction and creation of functional vascular networks has been one of the main goals of tissue engineering either in vitro, for the transplantation of prevascularized constructs, or in vivo, for cellular organization within the implantation site. In most cases, tissue engineering attempts to recapitulate certain aspects of normal development in order to stimulate cell differentiation and functional tissue assembly. The induction of tissue growth generally involves the use of biodegradable and bioactive materials designed, ideally, to provide a mechanical, physical, and biochemical template for tissue regeneration. Human embryonic stem cells (hESCs), derived from the inner cell mass of a developing blastocyst, are capable of differentiating into all cell types of the body. Specifically, hESCs have the capability to differentiate and form blood vessels de novo in a process called vasculogenesis. Human ESC-derived endothelial progenitor cells (EPCs) and endothelial cells have substantial potential for microvessel formation, in vitro and in vivo. Human adult EPCs are being isolated to understand the fundamental biology of how these cells are regulated as a population and to explore whether these cells can be differentiated and reimplanted as a cellular therapy in order to arrest or even reverse damaged vasculature. This chapter focuses on advances made toward the generation and engineering of functional vascular tissue, focusing on both the scaffolds - the synthetic and biopolymer materials - and the cell sources - hESCs and hEPCs.
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Affiliation(s)
- E Luong
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA
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30
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Abstract
This manuscript presents hydrogels (HGs) from a tissue engineering perspective being especially written for those who are approaching this field by offering a concise but inclusive review of hydrogel synthesis, properties, characterization methods, and applications.
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Affiliation(s)
- Biancamaria Baroli
- Dipartimento Farmaco Chimico Tecnologico, Università di Cagliari, Via Ospedale, 72, 09124 Cagliari, Italy.
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31
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Inanç B, Eser Elçin A, Koç A, Baloş K, Parlar A, Murat Elçin Y. Encapsulation and osteoinduction of human periodontal ligament fibroblasts in chitosan–hydroxyapatite microspheres. J Biomed Mater Res A 2007; 82:917-26. [PMID: 17335028 DOI: 10.1002/jbm.a.31213] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Periodontal ligament cells play a crucial role in the regeneration of periodontal tissues and an undifferentiated mesenchymal cell subset is thought to exist within this population. The aim of this study was to assess the osteogenic differentiation potential of human periodontal ligament fibroblasts (hPDLFs) in three dimensional (3D)-osteogenic culture environment following encapsulation in chitosan-hydroxyapatite (C/HA) microspheres with the size range of 350-450 microm. Human PDLF cultures were established and three experimental groups were formed: (i) two-dimensional (2D)-culture as single cell monolayer, (ii) 3D-static culture of C/HA encapsulated hPDLFs, and (iii) 3D-dynamic culture of C/HA encapsulated hPDLFs in a rotating wall vessel bioreactor. The cells were cultured in standard culture medium supplemented with beta-glycerophosphate, dexamethasone, and ascorbic acid. After 21 days, immunohistochemistry was performed using antibodies against osteonectin, osteopontin, bone-sialoprotein, and osteocalcin as osteogenic differentiation markers. Phase-contrast and scanning electron microscopy observations were used for histological and morphological evaluation. The combined effects of osteoinductive medium and HA-containing composite microsphere material on encapsulated hPDLFs resulted in the transformation of a considerable portion of the cells into osteoblastic lineage at the end of the experiments. Results demonstrate the ability of hPDLFs to undergo osteogenic differentiation upon induction in vitro, both under 2D and 3D culture conditions. C/HA microspheres in microgravity bioreactor may serve as a suitable 3D environment to support the osteogenic differentiation of human PDLFs, in vitro.
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Affiliation(s)
- Bülend Inanç
- Tissue Engineering and Biomaterials Laboratory, Biotechnology Institute, Faculty of Science, Ankara University, Ankara 06100, Turkey
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32
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Koç A, Durkut S, Elçin AE, Tan E, Elçin YM. Evaluation of Modified CMC and CMC-PVA as Miscible Polymer Blend Membranes for Hepatocytes. Macromol Biosci 2007; 7:681-9. [PMID: 17457936 DOI: 10.1002/mabi.200600265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
CMC and CMC-PVA were blended either with type I collagen, BSA or CS to obtain biocompatible membranes for evaluation as potential hepatocyte culture substrates. Pure and modified forms of CMC showed distinct surface, mechanical, and cell attachment properties. While the hydrophilicity decreased, the mechanical stability and the porosity of CMC membranes increased after blending. Serum proteins were adsorbed by all types of membranes. Among eight membranes tested, collagen-modified CMC was found to be a suitable membrane material for hepatocyte culture, in terms of mechanical and cell interaction properties.
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Affiliation(s)
- Aysel Koç
- Ankara University, Faculty of Science and Biotechnology Institute, Tissue Engineering and Biomaterials Laboratory, Ankara 06100, Turkey
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33
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Mathe Z, Dupraz P, Rinsch C, Thorens B, Bosco D, Zbinden M, Morel P, Berney T, Pepper MS. Tetracycline-regulated expression of VEGF-A in beta cells induces angiogenesis: improvement of engraftment following transplantation. Cell Transplant 2007; 15:621-36. [PMID: 17176614 DOI: 10.3727/000000006783981675] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Early revascularization of pancreatic islet cells after transplantation is crucial for engraftment, and it has been suggested that vascular endothelial growth factor-A (VEGF-A) plays a significant role in this process. Although VEGF gene therapy can improve angiogenesis, uncontrolled VEGF secretion can lead to vascular tumor formation. Here we have explored the role of temporal VEGF expression, controlled by a tetracycline (TC)-regulated promoter, on revascularization and engraftment of genetically modified beta cells following transplantation. To this end, we modified the CDM3D beta cell line using a lentiviral vector to promote secretion of VEGF-A either in a TC-regulated (TET cells) or a constitutive (PGK cells) manner. VEGF secretion, angiogenesis, cell proliferation, and stimulated insulin secretion were assessed in vitro. VEGF secretion was increased in TET and PGK cells, and VEGF delivery resulted in angiogenesis, whereas addition of TC inhibited these processes. Insulin secretion by the three cell types was similar. We used a syngeneic mouse model of transplantation to assess the effects of this controlled VEGF expression in vivo. Time to normoglycemia, intraperitoneal glucose tolerance test, graft vascular density, and cellular mass were evaluated. Increased expression of VEGF resulted in significantly better revascularization and engraftment after transplantation when compared to control cells. In vivo, there was a significant increase in vascular density in grafted TET and PGK cells versus control cells. Moreover, the time for diabetic mice to return to normoglycemia and the stimulated plasma glucose clearance were also significantly accelerated in mice transplanted with TET and PGK cells when compared to control cells. VEGF was only needed during the first 2-3 weeks after transplantation; when removed, normoglycemia and graft vascularization were maintained. TC-treated mice grafted with TC-treated cells failed to restore normoglycemia. This approach allowed us to switch off VEGF secretion when the desired effects had been achieved. TC-regulated temporal expression of VEGF using a gene therapy approach presents a novel way to improve early revascularization and engraftment after islet cell transplantation.
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Affiliation(s)
- Zoltan Mathe
- Transplantation and Surgical Department, Semmelweis University, Budapest, H-1089, Hungary
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34
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Blomeier H, Zhang X, Rives C, Brissova M, Hughes E, Baker M, Powers AC, Kaufman DB, Shea LD, Lowe WL. Polymer scaffolds as synthetic microenvironments for extrahepatic islet transplantation. Transplantation 2006; 82:452-9. [PMID: 16926587 PMCID: PMC2648394 DOI: 10.1097/01.tp.0000231708.19937.21] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Problems associated with the hepatic transplantation of islets may preclude the broad application of islet transplantation. Thus, we sought to develop an approach to the extrahepatic transplantation of islets using a synthetic biodegradable polymer scaffold. METHODS Microporous polymer scaffolds that allow vascular ingrowth and nutrient diffusion from host tissues were fabricated from copolymers of lactide and glycolide. Murine islets were transplanted without or with a scaffold onto intraperitoneal fat of syngeneic diabetic recipients. Bioluminescence imaging using a cooled charge-coupled device camera, immunohistochemistry, and glycemia were used to assess islet engraftment and function posttransplant. RESULTS By bioluminescence imaging, islets transplanted on a polymer scaffold remain localized to the transplant site and survive for an extended period of time. Islets transplanted on scaffolds retained the architecture of native islets and developed a functional islet vasculature. Transplantation of marginal masses of islets on the polymer scaffold demonstrated improved islet function compared to transplantation without a scaffold as assessed by the effectiveness of diabetes reversal, including mean time required to achieve euglycemia, weight gain, and glucose levels during an intraperitoneal glucose tolerance test. CONCLUSION These findings indicate that a synthetic polymer scaffold can serve as a platform for islet transplantation and improves the function of extrahepatically transplanted islets compared to islets transplanted without a scaffold. The scaffold may also be useful to deliver bioactive molecules to modify the microenvironment surrounding the transplanted islets and, thus, enhance islet survival and function.
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Affiliation(s)
- Herman Blomeier
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Xiaomin Zhang
- Department of Surgery, Division of Transplant Surgery, Northwestern, University Feinberg School of Medicine, Chicago, IL
| | - Christopher Rives
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL
| | - Marcela Brissova
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN
| | - Elizabeth Hughes
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Marshall Baker
- Department of Surgery, Division of Transplant Surgery, Northwestern, University Feinberg School of Medicine, Chicago, IL
| | - Alvin C. Powers
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN
- VA Tennessee Valley Healthcare System, Nashville, TN
| | - Dixon B. Kaufman
- Department of Surgery, Division of Transplant Surgery, Northwestern, University Feinberg School of Medicine, Chicago, IL
| | - Lonnie D. Shea
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL
| | - William L. Lowe
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
- Address correspondence to: William L. Lowe, Jr., M.D., Center for Endocrinology, Metabolism, and Molecular Medicine, Tarry 15-703, Northwestern University Feinberg School of Medicine, 303 East Chicago Ave., Chicago, IL 60611. E-mail:
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Linn T, Schmitz J, Hauck-Schmalenberger I, Lai Y, Bretzel RG, Brandhorst H, Brandhorst D. Ischaemia is linked to inflammation and induction of angiogenesis in pancreatic islets. Clin Exp Immunol 2006; 144:179-87. [PMID: 16634789 PMCID: PMC1809653 DOI: 10.1111/j.1365-2249.2006.03066.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Beta-cell replacement is the only way to restore euglycaemia in patients with type-1 diabetes. Pancreatic tissue, processed for subsequent clinical islet transplantation, is exposed to ischaemia causing injury and death in a large number of islets before and after transplantation. In this review we summarize what is known on the sources of environmental stress for pancreatic islets, such as insufficient oxygen supply during pancreas procurement and in culture prior to intraportal transplantation, nutritional and oxygen deprivation during the isolation process, and the consequences of hyperglycaemia. An increasingly recognized role in the modulation of beta-cell function and these environmental stress factors plays the vascular network of the pancreatic islets. Islet revascularization by angiogenesis is relevant for the survival of the graft subsequent to transplantation. Potential strategies offered by therapeutic induction of revascularization to ameliorate the detrimental impact of these factors on the quality of islet transplants are discussed.
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Affiliation(s)
- T Linn
- Medical Clinic and Policlinic 3, University Hospital Giessen and Marburg, Justus Liebig University, Rodthohl 6, 35385 Giessen, Germany.
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Nakase Y, Hagiwara A, Nakamura T, Kin S, Nakashima S, Yoshikawa T, Fukuda KI, Kuriu Y, Miyagawa K, Sakakura C, Otsuji E, Shimizu Y, Ikada Y, Yamagishi H. Tissue engineering of small intestinal tissue using collagen sponge scaffolds seeded with smooth muscle cells. ACTA ACUST UNITED AC 2006; 12:403-12. [PMID: 16548698 DOI: 10.1089/ten.2006.12.403] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In a previously reported attempt to regenerate small intestine with autologous tissues, collagen scaffolds were used without cell seeding or with autologous mesenchymal stem cell seeding. However the regenerated intestine lacked a smooth muscle layer. To accomplish regeneration of a smooth muscle layer, this present study used collagen scaffolds seeded with the smooth muscle cells (SMC) in a canine model. Autologous SMC were isolated from stomach wall and cultured. Two types of scaffolds were fabricated: in SMC (+), cultured SMCs were mixed with collagen solution and poured into a collagen sponge; and in SMC (-), SMCs were omitted. Both scaffolds were implanted into defects of isolated ileum as a patch graft. Animals were euthanized at 4, 8, and 12 weeks; for the last time point, the ileal loop had been reanastomosed at 8 weeks. At 12 weeks, the SMC (-) group showed a luminal surface covered by a regenerated epithelial cell layer with very short villi; however only a thin smooth muscle layer was observed, representing the muscularis mucosae. In the SMC (+) group, the luminal surface was covered completely by a relatively well-developed epithelial layer with numerous villi. Implanted SMCs were seen in the lamina propria and formed a smooth muscle layer. Thus, we concluded that collagen sponge scaffolds seeded with autologous SMCs have a potential for small intestine regeneration.
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Affiliation(s)
- Yuen Nakase
- Department of Surgery and Regenerative Medicine, Division of Surgery and Physiology of Digestive System, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
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Shi C, Zhu Y, Ran X, Wang M, Su Y, Cheng T. Therapeutic potential of chitosan and its derivatives in regenerative medicine. J Surg Res 2006; 133:185-92. [PMID: 16458923 DOI: 10.1016/j.jss.2005.12.013] [Citation(s) in RCA: 294] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 11/28/2005] [Accepted: 12/15/2005] [Indexed: 01/21/2023]
Abstract
BACKGROUND Cell-based transplantation, tissue engineering and gene therapy are important therapeutic strategies for present and future regenerative medicine. One challenge is to present the target cells in a suitable matrix to allow the cells to survive the wound contraction, tissue repair, and remodeling in certain tissues. Recently, functional biomaterial research has been directed towards the development of improved scaffolds and new drug delivery systems for regenerative medicine. MATERIALS AND METHODS A literature survey was performed in basic and clinic publications relevant to the therapeutic potential of chitosan and its derivatives in regenerative medicine. In this review the functional properties and potential applications of chitosan and its derivatives in regenerative medicine are presented and discussed. RESULTS Chitosan can be obtained by alkaline deacetylation of chitin and is found to be a natural-based nontoxic, biocompatible, and biodegradable polymer with anti-microbial activity. Chitosan and its derivatives could accelerate wound healing by enhancing the functions of inflammatory cells and repairing cells. Recent studies further indicated that chitosan and its derivatives also are novel scaffold materials for tissue engineering and are-promising non-viral vectors for gene delivery. CONCLUSIONS Regenerative medicine has entered a new era with the development of modern science and technology. The novel properties of chitosan make it a versatile biomaterial for cell therapy, tissue engineering and gene therapy. It is hoped that these diverse approaches for regenerative medicine will translate from "bench to bedside" in the future.
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Affiliation(s)
- Chunmeng Shi
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury, College of Preventive Medicine, Third Military Medical University, Chongqing, China.
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Lai Y, Schneider D, Kidszun A, Hauck-Schmalenberger I, Breier G, Brandhorst D, Brandhorst H, Iken M, Brendel MD, Bretzel RG, Linn T. Vascular endothelial growth factor increases functional beta-cell mass by improvement of angiogenesis of isolated human and murine pancreatic islets. Transplantation 2005; 79:1530-6. [PMID: 15940042 DOI: 10.1097/01.tp.0000163506.40189.65] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Blood flow is impaired in islet transplants, but there is conflicting evidence on improving the outcome by promoting vascularization. We previously reported that islet endothelial cells (EC) possess significant angiogenic capacity. METHODS To further address this issue, we studied human islets in culture under hypoxic conditions. Moreover, we used a transgene mouse model with human vascular endothelial growth factor (VEGF) production in beta-cells under the control of the rat insulin promoter (RIP) to stimulate islet EC proliferation. RESULTS Subsequent to a hypoxic stimulus, islets responded with specific expression patterns of VEGF and fibroblast growth factor; however, this was not sufficient to prevent the decay of islet EC. VEGF release of RIP-VEGF transgenic islets was controlled by glucose and resulted in the formation of sprouts. When transplanted to the kidney capsule of diabetic mice, RIP-VEGF islets significantly enhanced microvascular density and functional blood flow to the graft compared with controls. CONCLUSIONS Optimized angiogenesis of islet transplants resulted in greater availability of insulin caused by beta-cell proliferation and a significantly higher percentage (90% versus 20%) of mice cured from diabetes.
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Affiliation(s)
- Yi Lai
- Medical Clinic and Policlinic 3, Justus-Liebig-University, 35392 Giessen, Germany
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Kannan RY, Salacinski HJ, Sales K, Butler P, Seifalian AM. The roles of tissue engineering and vascularisation in the development of micro-vascular networks: a review. Biomaterials 2005; 26:1857-75. [PMID: 15576160 DOI: 10.1016/j.biomaterials.2004.07.006] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/05/2004] [Indexed: 11/16/2022]
Abstract
The construction of tissue-engineered devices for medical applications is now possible in vitro using cell culture and bioreactors. Although methods of incorporating them back into the host are available, current constructs depend purely on diffusion which limits their potential. The absence of a vascular network capable of distributing oxygen and other nutrients within the tissue-engineered device is a major limiting factor in creating vascularised artificial tissues. Though bio-hybrid prostheses such as vascular bypass grafts and skin substitutes have already been developed and are being used clinically, the absence of a capillary bed linking the two systems remains the missing link. In this review, the different approaches currently being or that have been applied to vascularise tissues are identified and discussed.
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Affiliation(s)
- Ruben Y Kannan
- Biomaterials & Tissue Engineering Centre (BTEC), University Department of Surgery, Royal Free and University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK
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Cheng K, Fraga D, Zhang C, Kotb M, Gaber AO, Guntaka RV, Mahato RI. Adenovirus-based vascular endothelial growth factor gene delivery to human pancreatic islets. Gene Ther 2004; 11:1105-16. [PMID: 15238996 DOI: 10.1038/sj.gt.3302267] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Islet transplantation is limited by islet graft failure due to poor revascularization, host immune rejection and nonspecific inflammatory response. Delivery of human vascular endothelial growth factor (hVEGF) gene to the islets is likely to promote islet revascularization and survival. We used a bicistronic adenoviral vector encoding hVEGF and CpG-free allele of green fluorescent protein (Adv-GFP-hVEGF) and introduced into human pancreatic islets by transfection. We found that transfection efficiency and apoptosis were dependent on the multiplicity of infection (MOI). Compared to Adv-GFP transfected and nontransfected islets, the levels of hVEGF secreted from Adv-GFP-hVEGF transfected islets were higher and exhibit a linear relationship between hVEGF expression and MOI (10-5000). Persistent, but low level expression of hVEGF from nontransfected islets was also observed. This may be due to expression of the endogenous hVEGF gene under hypoxic conditions. The levels of DNA fragmentation determined by ELISA of islet lysates were dependent on the MOI of Adv-GFP-hVEGF. On glucose challenge, insulin release from transfected islets was comparable to nontransfected islets. Immunohistochemical staining for hVEGF was very high in Adv-GFP-hVEGF transfected islets. Weak staining was also observed for hCD31 in both transfected and nontransfected islets. These findings suggest that Adv-GFP-hVEGF is a potential candidate for promoting islet revascularization.
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Affiliation(s)
- K Cheng
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
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