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Martin WT, Bonds M, Fischer L, Morris KT, Sarwar Z, Stewart K, Garwe T, Paniccia A, Schulick RD, Jain A, Edil BH. Learning Curve of a Laparoscopic Pancreaticoduodenectomy Program at a Second Institution. Am Surg 2024:31348241246163. [PMID: 38587270 DOI: 10.1177/00031348241246163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
BACKGROUND Historically, pancreaticoduodenectomy (PD) has been performed via a laparotomy, but increasingly, laparoscopic and robotic platforms are being employed for PD. Laparoscopic PD has a steep surgeon specific learning curve and programmatic elements that must be optimized. These factors may limit a surgeon who is proficient at laparoscopic PD to develop a program at another institution. We hypothesize that the learning curve for a surgeon transferring a program to a second institution is shorter than the initial laparoscopic PD learning curve for the same surgeon. METHODS A retrospective review of patients who underwent laparoscopic PD for any indication at the first institution (FI) from 2012 to 2017 and the second institution (SI) from 2018 to 2021 was conducted. Standard statistical analysis was performed. The learning curve was identified using one-sided CUSUM analysis of operative times. RESULT We identified 110 participants, 90 from the FI and 20 from the SI. More patients at the FI were diagnosed with periampullary adenocarcinoma on final pathology compared to the SI (65.6% vs 40.0%, P = .0132). FI operative times stabilized after the 25th laparoscopic PD and SI operative times stabilized after the 5th operation. No statistically significant difference was identified in postoperative complications. CONCLUSIONS The learning curve and average operative time of an SI laparoscopic PD program was shorter than the initial learning curve for a single surgeon with comparable outcomes. This suggests that complex minimally invasive surgical programs can be safely transferred to another high-volume institution without significant loss of progress.
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Affiliation(s)
- W Taylor Martin
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Morgan Bonds
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Laura Fischer
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Katherine T Morris
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zoona Sarwar
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Kenneth Stewart
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Tabitha Garwe
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Alessandro Paniccia
- Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Richard D Schulick
- Department of Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ajay Jain
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Barish H Edil
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Garcia Valencia OA, Thongprayoon C, Jadlowiec CC, Mao SA, Leeaphorn N, Budhiraja P, Khoury N, Vaitla P, Suppadungsuk S, Cheungpasitporn W. Evaluating Global and Temporal Trends in Pancreas and Islet Cell Transplantation: Public Awareness and Engagement. Clin Pract 2024; 14:590-601. [PMID: 38666804 PMCID: PMC11049129 DOI: 10.3390/clinpract14020046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Pancreas transplantation is a crucial surgical intervention for managing diabetes, but it faces challenges such as its invasive nature, stringent patient selection criteria, organ scarcity, and centralized expertise. Despite the steadily increasing number of pancreas transplants in the United States, there is a need to understand global trends in interest to increase awareness of and participation in pancreas and islet cell transplantation. METHODS We analyzed Google Search trends for "Pancreas Transplantation" and "Islet Cell Transplantation" from 2004 to 14 November 2023, assessing variations in search interest over time and across geographical locations. The Augmented Dickey-Fuller (ADF) test was used to determine the stationarity of the trends (p < 0.05). RESULTS Search interest for "Pancreas Transplantation" varied from its 2004 baseline, with a general decline in peak interest over time. The lowest interest was in December 2010, with a slight increase by November 2023. Ecuador, Kuwait, and Saudi Arabia showed the highest search interest. "Islet Cell Transplantation" had its lowest interest in December 2016 and a more pronounced decline over time, with Poland, China, and South Korea having the highest search volumes. In the U.S., "Pancreas Transplantation" ranked 4th in interest, while "Islet Cell Transplantation" ranked 11th. The ADF test confirmed the stationarity of the search trends for both procedures. CONCLUSIONS "Pancreas Transplantation" and "Islet Cell Transplantation" showed initial peaks in search interest followed by a general downtrend. The stationary search trends suggest a lack of significant fluctuations or cyclical variations. These findings highlight the need for enhanced educational initiatives to increase the understanding and awareness of these critical transplant procedures among the public and professionals.
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Affiliation(s)
- Oscar A. Garcia Valencia
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA; (O.A.G.V.); (S.S.); (W.C.)
| | - Charat Thongprayoon
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA; (O.A.G.V.); (S.S.); (W.C.)
| | - Caroline C. Jadlowiec
- Division of Transplant Surgery, Department of Surgery, Mayo Clinic, Phoenix, AZ 85054, USA;
| | - Shennen A. Mao
- Division of Transplant Surgery, Department of Surgery, Mayo Clinic, Jacksonville, FL 32224, USA; (S.A.M.); (N.L.)
| | - Napat Leeaphorn
- Division of Transplant Surgery, Department of Surgery, Mayo Clinic, Jacksonville, FL 32224, USA; (S.A.M.); (N.L.)
| | - Pooja Budhiraja
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Phoenix, AZ 85054, USA;
| | - Nadeen Khoury
- Division of Nephrology, Henry Ford Hospital, Detroit, MI 48202, USA;
| | - Pradeep Vaitla
- Division of Nephrology, University of Mississippi Medical Center, Jackson, MS 39216, USA;
| | - Supawadee Suppadungsuk
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA; (O.A.G.V.); (S.S.); (W.C.)
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan 10540, Thailand
| | - Wisit Cheungpasitporn
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA; (O.A.G.V.); (S.S.); (W.C.)
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Einstein SA, Steyn LV, Weegman BP, Suszynski TM, Sambanis A, O'Brien TD, Avgoustiniatos ES, Firpo MT, Graham ML, Janecek J, Eberly LE, Garwood M, Putnam CW, Papas KK. Hypoxia within subcutaneously implanted macroencapsulation devices limits the viability and functionality of densely loaded islets. FRONTIERS IN TRANSPLANTATION 2023; 2:1257029. [PMID: 38993891 PMCID: PMC11235299 DOI: 10.3389/frtra.2023.1257029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/20/2023] [Indexed: 07/13/2024]
Abstract
Introduction Subcutaneous macroencapsulation devices circumvent disadvantages of intraportal islet therapy. However, a curative dose of islets within reasonably sized devices requires dense cell packing. We measured internal PO2 of implanted devices, mathematically modeled oxygen availability within devices and tested the predictions with implanted devices containing densely packed human islets. Methods Partial pressure of oxygen (PO2) within implanted empty devices was measured by noninvasive 19F-MRS. A mathematical model was constructed, predicting internal PO2, viability and functionality of densely packed islets as a function of external PO2. Finally, viability was measured by oxygen consumption rate (OCR) in day 7 explants loaded at various islet densities. Results In empty devices, PO2 was 12 mmHg or lower, despite successful external vascularization. Devices loaded with human islets implanted for 7 days, then explanted and assessed by OCR confirmed trends proffered by the model but viability was substantially lower than predicted. Co-localization of insulin and caspase-3 immunostaining suggested that apoptosis contributed to loss of beta cells. Discussion Measured PO2 within empty devices declined during the first few days post-transplant then modestly increased with neovascularization around the device. Viability of islets is inversely related to islet density within devices.
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Affiliation(s)
- Samuel A Einstein
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States
- Department of Radiology, The Pennsylvania State University, Hershey, PA, United States
| | - Leah V Steyn
- Department of Surgery, University of Arizona, Tucson, AZ, United States
| | - Bradley P Weegman
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States
- Sylvatica Biotech Inc., North Charleston, SC, United States
| | - Thomas M Suszynski
- Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Athanassios Sambanis
- Department of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Timothy D O'Brien
- Veterinary Population Medicine Department, University of Minnesota, Saint Paul, MN, United States
- Department of Medicine, Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | | | - Meri T Firpo
- Department of Medicine, Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Melanie L Graham
- Veterinary Population Medicine Department, University of Minnesota, Saint Paul, MN, United States
- Department of Surgery, Preclinical Research Center, University of Minnesota, Saint Paul, MN, United States
| | - Jody Janecek
- Department of Surgery, Preclinical Research Center, University of Minnesota, Saint Paul, MN, United States
| | - Lynn E Eberly
- Division of Biostatistics, University of Minnesota, Minneapolis, MN, United States
| | - Michael Garwood
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States
| | - Charles W Putnam
- Department of Surgery, University of Arizona, Tucson, AZ, United States
| | - Klearchos K Papas
- Department of Surgery, University of Arizona, Tucson, AZ, United States
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Mishra S, Streeter PR. Targeted delivery of harmine to xenografted human pancreatic islets promotes robust cell proliferation. Sci Rep 2022; 12:19127. [PMID: 36351917 PMCID: PMC9646720 DOI: 10.1038/s41598-022-19453-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 08/29/2022] [Indexed: 11/11/2022] Open
Abstract
Type 1 diabetes (T1D) occurs as a consequence of the autoimmune destruction of insulin-producing pancreatic beta (β) cells and commonly presents with insulin deficiency and unregulated glycemic control. Despite improvements in the medical management of T1D, life-threatening complications are still common. Beta-cell replication to replace lost cells may be achieved by using small-molecule mitogenic drugs, like harmine. However, the safe and effective delivery of such drugs to beta cells remains a challenge. This work aims to deploy an antibody conjugated nanocarrier platform to achieve cell-specific delivery of candidate therapeutic and imaging agents to pancreatic endocrine cells. We approached this goal by generating core-shell type micellar nanocarriers composed of the tri-block copolymer, Pluronic®F127 (PEO100-PPO65-PEO100). We decorated these nanocarriers with a pancreatic endocrine cell-selective monoclonal antibody (HPi1), with preference for beta cells, to achieve active targeting. The PPO-based hydrophobic core allows encapsulation of various hydrophobic cargoes, whereas the PEO-based hydrophilic shell curbs the protein adhesion, hence prolonging the nanocarriers' systemic circulation time. The nancarriers were loaded with quantum dots (QDots) that allowed nanocarrier detection both in-vitro and in-vivo. In-vitro studies revealed that HPi1 conjugated nanocarriers could target endocrine cells in dispersed islet cell preparations with a high degree of specificity, with beta cells exhibiting a fluorescent quantum dot signal that was approximately five orders of magnitude greater than the signal associated with alpha cells. In vivo endocrine cell targeting studies demonstrated that the HPi1 conjugated nanocarriers could significantly accumulate at the islet xenograft site. For drug delivery studies, the nanocarriers were loaded with harmine. We demonstrated that HPi1 conjugated nanocarriers successfully targeted and delivered harmine to human endocrine cells in a human islet xenograft model. In this model, targeted harmine delivery yielded an ~ 41-fold increase in the number of BrdU positive cells in the human islet xenograft than that observed in untreated control mice. By contrast, non-targeted harmine yielded an ~ 9-fold increase in BrdU positive cells. We conclude that the nanocarrier platform enabled cell-selective targeting of xenografted human pancreatic endocrine cells and the selective delivery of the hydrophobic drug harmine to those cells. Further, the dramatic increase in proliferation with targeted harmine, a likely consequence of achieving higher local drug concentrations, supports the concept that targeted drug delivery may promote more potent biological responses when using harmine and/or other drugs than non-targeting approaches. These results suggest that this targeted drug delivery platform may apply in drug screening, beta cell regenerative therapies, and/or diagnostic imaging in patients with type 1 diabetes.
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Affiliation(s)
- Swati Mishra
- grid.5288.70000 0000 9758 5690Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Oregon Health and Science University, Portland, OR USA
| | - Philip R. Streeter
- grid.5288.70000 0000 9758 5690Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Oregon Health and Science University, Portland, OR USA
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5
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The MHC-characterized Miniature Swine: Lessons Learned From a 40-Year Experience in Transplantation. Transplantation 2021; 106:928-937. [PMID: 34720103 DOI: 10.1097/tp.0000000000003977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Over the last 40 y, a specialized herd of miniature swine has been intentionally bred to develop lines of animals homozygous for the swine major histocompatibility complex (MHC), which have facilitated transplantation studies across reproducible MHC and minor antigen mismatch barriers. These MHC-characterized miniature swine (Mc-MS) have been used for the study of novel surgical techniques, various approaches to tolerance induction of solid organ and vascularized composite allografts, as well as studies of the immunobiology of allografts and xenografts. Mc-MS possess characteristics that are highly advantageous to these studies, and their continued use will likely continue to play an important role in bridging "bench-to-cage-to bedside" therapies in the field of transplantation. In this review, we highlight the seminal contributions of the Mc-MS model to the field and analyze their role in the broader context of large animal models in transplantation research.
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Tissue Engineering Strategies for Improving Beta Cell Transplantation Outcome. CURRENT TRANSPLANTATION REPORTS 2021. [DOI: 10.1007/s40472-021-00333-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Purpose of Review
Beta cell replacement therapy as a form of islet transplantation is a promising alternative therapy with the possibility to make selected patients with type 1 diabetes (T1D) insulin independent. However, this technique faces challenges such as extensive activation of the host immune system post-transplantation, lifelong need for immunosuppression, and the scarcity of islet donor pancreas. Advancement in tissue engineering strategies can improve these challenges and allow for a more widespread application of this therapy. This review will discuss the recent development and clinical translation of tissue engineering strategies in beta cell replacement therapy.
Recent Findings
Tissue engineering offers innovative solutions for producing unlimited glucose responsive cells and fabrication of appropriate devices/scaffolds for transplantation applications. Generation of pancreatic organoids with supporting cells in biocompatible biomaterials is a powerful technique to improve the function of insulin-producing cell clusters. Fabrication of physical barriers such as encapsulation strategies can protect the cells from the host immune system and allow for graft retrieval, although this strategy still faces major challenges to fully restore physiological glucose regulation.
Summary
The three main components of tissue engineering strategies including the generation of stem cell-derived insulin-producing cells and organoids and the possibilities for therapeutic delivery of cell-seeded devices to extra-hepatic sites need to come together in order to provide safe and functional insulin-producing devices for clinical beta cell replacement therapy.
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Alekberzade AV, Krylov NN, Adzhun Z, Laftavi MR, Shakhbazov RO, Zuykova KS. [Current state of the problem of allotransplantation of Langerhans cells (achievements and prospects)]. Khirurgiia (Mosk) 2018:80-88. [PMID: 30531761 DOI: 10.17116/hirurgia201811180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Literature data devoted to transplantation of Langerhans cells have been analyzed. The main stages, indications, dissection of islets, immunosuppressive therapy, complications and data of the latest clinical trials were discussed.
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Affiliation(s)
- A V Alekberzade
- Sechenov First Moscow State Medical University of Healthcare Ministry of the Russian Federation, Moscow, Russia
| | - N N Krylov
- Sechenov First Moscow State Medical University of Healthcare Ministry of the Russian Federation, Moscow, Russia
| | - Z Adzhun
- Upstate Medical University, Syracuse, NY, USA
| | - M R Laftavi
- Upstate Medical University, Syracuse, NY, USA
| | | | - K S Zuykova
- Sechenov First Moscow State Medical University of Healthcare Ministry of the Russian Federation, Moscow, Russia
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Navaei-Nigjeh M, Moloudizargari M, Baeeri M, Gholami M, Lotfibakhshaiesh N, Soleimani M, Vasheghani-Farahani E, Ai J, Abdollahi M. Reduction of marginal mass required for successful islet transplantation in a diabetic rat model using adipose tissue-derived mesenchymal stromal cells. Cytotherapy 2018; 20:1124-1142. [PMID: 30068495 DOI: 10.1016/j.jcyt.2018.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/10/2018] [Accepted: 06/06/2018] [Indexed: 12/16/2022]
Abstract
BACKGROUND AIMS Adipose tissue-derived mesenchymal stromal cells (AT-MSCs), widely known as multipotent progenitors, release several cytokines that support cell survival and repair. There are in vitro and in vivo studies reporting the regenerative role of AT-MSCs possibly mediated by their protective effects on functional islet cells as well as their capacity to differentiate into insulin-producing cells (IPCs). METHODS On such a basis, our goal in the present study was to use three different models including direct and indirect co-cultures and islet-derived conditioned medium (CM) to differentiate AT-MSCs into IPCs and to illuminate the molecular mechanisms of the beneficial impact of AT-MSCs on pancreatic islet functionality. Furthermore, we combined in vitro co-culture of islets and AT-MSCs with in vivo assessment of islet graft function to assess whether co-transplantation of islets with AT-MSCs can reduce marginal mass required for successful islet transplantation and prolong graft function in a diabetic rat model. RESULTS Our findings demonstrated that AT-MSCs are suitable for creating a microenvironment favorable for the repair and longevity of the pancreas β cells through the improvement of islet survival and maintenance of cell morphology and insulin secretion due to their potent properties in differentiation. Most importantly, hybrid transplantation of islets with AT-MSCs significantly promoted survival, engraftment and insulin-producing function of the graft and reduced the islet mass required for reversal of diabetes. CONCLUSIONS This strategy might be of therapeutic potential solving the problem of donor islet material loss that currently limits the application of allogeneic islet transplantation as a more widespread therapy for type 1 diabetes.
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Affiliation(s)
- Mona Navaei-Nigjeh
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Science, Tehran, Iran
| | - Milad Moloudizargari
- Student Research Committee, Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Baeeri
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Science, Tehran, Iran
| | - Mahdi Gholami
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Science, Tehran, Iran
| | - Nasrin Lotfibakhshaiesh
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Soleimani
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Jafar Ai
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Science, Tehran, Iran; Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
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Bowers DT, Olingy CE, Chhabra P, Langman L, Merrill PH, Linhart RS, Tanes ML, Lin D, Brayman KL, Botchwey EA. An engineered macroencapsulation membrane releasing FTY720 to precondition pancreatic islet transplantation. J Biomed Mater Res B Appl Biomater 2018; 106:555-568. [PMID: 28240814 PMCID: PMC5572559 DOI: 10.1002/jbm.b.33862] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/28/2016] [Accepted: 01/26/2017] [Indexed: 02/06/2023]
Abstract
Macroencapsulation is a powerful approach to increase the efficiency of extrahepatic pancreatic islet transplant. FTY720, a small molecule that activates signaling through sphingosine-1-phosphate receptors, is immunomodulatory and pro-angiogenic upon sustained delivery from biomaterials. While FTY720 (fingolimod, Gilenya) has been explored for organ transplantation, in the present work the effect of locally released FTY720 from novel nanofiber-based macroencapsulation membranes is explored for islet transplantation. We screened islet viability during culture with FTY720 and various biodegradable polymers. Islet viability is significantly reduced by the addition of high doses (≥500 ng/mL) of soluble FTY720. Among the polymers screened, islets have the highest viability when cultured with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Therefore, PHBV was blended with polycaprolactone (PCL) for mechanical stability and electrospun into nanofibers. Islets had no detectable function ex vivo following 5 days or 12 h of subcutaneous implantation within our engineered device. Subsequently, we explored a preconditioning scheme in which islets are transplanted 2 weeks after FTY720-loaded nanofibers are implanted. This allows FTY720 to orchestrate a local regenerative milieu while preventing premature transplantation into avascular sites that contain high concentrations of FTY720. These results provide a foundation and motivation for further investigation into the use of FTY720 in preconditioning sites for efficacious islet transplantation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 555-568, 2018.
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Affiliation(s)
- Daniel T Bowers
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
| | - Claire E Olingy
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, 30332-0363
| | - Preeti Chhabra
- Department of Surgery, University of Virginia, Charlottesville, Virginia, 22903
| | - Linda Langman
- Department of Surgery, University of Virginia, Charlottesville, Virginia, 22903
| | - Parker H Merrill
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
| | - Ritu S Linhart
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
| | - Michael L Tanes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
| | - Dan Lin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
| | - Kenneth L Brayman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
- Department of Surgery, University of Virginia, Charlottesville, Virginia, 22903
| | - Edward A Botchwey
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, 30332-0363
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10
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Wallner K, Pedroza RG, Awotwe I, Piret JM, Senior PA, Shapiro AMJ, McCabe C. Stem cells and beta cell replacement therapy: a prospective health technology assessment study. BMC Endocr Disord 2018; 18:6. [PMID: 29382312 PMCID: PMC5791348 DOI: 10.1186/s12902-018-0233-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 01/23/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Although current beta cell replacement therapy is effective in stabilizing glycemic control in highly selected patients with refractory type 1 diabetes, many hurdles are inherent to this and other donor-based transplantation methods. One solution could be moving to stem cell-derived transplant tissue. This study investigates a novel stem cell-derived graft and implant technology and explores the circumstances of its cost-effectiveness compared to intensive insulin therapy. METHODS We used a manufacturing optimization model based on work by Simaria et al. to model cost of the stem cell-based transplant doses and integrated its results into a cost-effectiveness model of diabetes treatments. The disease model simulated marginal differences in clinical effects and costs between the new technology and our comparator intensive insulin therapy. The form of beta cell replacement therapy was as a series of retrievable subcutaneous implant devices which protect the enclosed pancreatic progenitors cells from the immune system. This approach was presumed to be as effective as state of the art islet transplantation, aside from immunosuppression drawbacks. We investigated two different cell culture methods and several production and delivery scenarios. RESULTS We found the likely range of treatment costs for this form of graft tissue for beta cell replacement therapy. Additionally our results show this technology could be cost-effective compared to intensive insulin therapy, at a willingness-to-pay threshold of $100,000 per quality-adjusted life year. However, results also indicate that mass production has by far the best chance of providing affordable graft tissue, while overall there seems to be considerable room for cost reductions. CONCLUSIONS Such a technology can improve treatment access and quality of life for patients through increased graft supply and protection. Stem cell-based implants can be a feasible way of treating a wide range of patients with type 1 diabetes.
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Affiliation(s)
- Klemens Wallner
- Department of Emergency Medicine Research Group, Department of Emergency Medicine, University of Alberta, 8303 - 112 Street, Edmonton, AB T6G 2T4 Canada
| | - Rene G. Pedroza
- Michael Smith Laboratories and Department of Chemical & Biological Engineering, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Isaac Awotwe
- Department of Emergency Medicine Research Group, Department of Emergency Medicine, University of Alberta, 8303 - 112 Street, Edmonton, AB T6G 2T4 Canada
| | - James M. Piret
- Michael Smith Laboratories and Department of Chemical & Biological Engineering, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Peter A. Senior
- Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB T6G 2C8 Canada
- Department of Medicine, University of Alberta, Edmonton, Canada
| | - A. M. James Shapiro
- Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB T6G 2C8 Canada
- Department of Medicine, University of Alberta, Edmonton, Canada
- Department of Surgery, University of Alberta, Edmonton, AB Canada
| | - Christopher McCabe
- Department of Emergency Medicine Research Group, Department of Emergency Medicine, University of Alberta, 8303 - 112 Street, Edmonton, AB T6G 2T4 Canada
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11
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Tatum JA, Meneveau MO, Brayman KL. Single-donor islet transplantation in type 1 diabetes: patient selection and special considerations. Diabetes Metab Syndr Obes 2017; 10:73-78. [PMID: 28280376 PMCID: PMC5338842 DOI: 10.2147/dmso.s105692] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Type 1 diabetes mellitus is an autoimmune disorder of the endocrine pancreas that currently affects millions of people in the United States. Although the disease can be managed with exogenous insulin administration, the ultimate cure for the condition lies in restoring a patient's ability to produce their own insulin. Islet cell allotransplantation provides a means of endogenous insulin production. Though far from perfected, islet transplants are now a proven treatment for type 1 diabetics. However, proper patient selection is critical for achieving optimal outcomes. Given the shortage of transplantable organs, selecting appropriate candidates for whom the procedure will be of greatest benefit is essential. Although many of those who receive islets do not retain insulin independence, grafts do play a significant role in preventing hypoglycemic episodes that can be quite detrimental to quality of life and potentially fatal. Additionally, islet transplant requires lifelong immunosuppression. Antibodies, both preformed and following islet infusion, may play important roles in graft outcomes. Finally, no procedure is without inherent risk and islet transfusions can have serious consequences for recipients' livers in the form of both vascular and metabolic complications. Therefore, patient-specific factors that should be taken into account before islet transplantation include aims of therapy, sensitization, and potential increased risk for hepatic and portal-venous sequelae.
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Affiliation(s)
- Jacob A Tatum
- Department of Surgery, Division of Transplantation, The University of Virginia Health System, Charlottesville, VA, USA
| | - Max O Meneveau
- Department of Surgery, Division of Transplantation, The University of Virginia Health System, Charlottesville, VA, USA
| | - Kenneth L Brayman
- Department of Surgery, Division of Transplantation, The University of Virginia Health System, Charlottesville, VA, USA
- Correspondence: Kenneth L Brayman, Department of Surgery, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22908, USA, Tel +1 434 924 9370, Fax +1 434 924 5539, Email
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Green AD, Vasu S, McClenaghan NH, Flatt PR. Implanting 1.1B4 human β-cell pseudoislets improves glycaemic control in diabetic severe combined immune deficient mice. World J Diabetes 2016; 7:523-533. [PMID: 27895821 PMCID: PMC5107712 DOI: 10.4239/wjd.v7.i19.523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 06/01/2016] [Accepted: 08/31/2016] [Indexed: 02/05/2023] Open
Abstract
AIM To investigate the potential of implanting pseudoislets formed from human insulin-releasing β-cell lines as an alternative to islet transplantation.
METHODS In this study, the anti-diabetic potential of novel human insulin releasing 1.1B4 β-cells was evaluated by implanting the cells, either as free cell suspensions, or as three-dimensional pseudoislets, into the subscapular region of severe combined immune deficient mice rendered diabetic by single high-dose administration of streptozotocin. Metabolic parameters including food and fluid intake, bodyweight and blood glucose were monitored throughout the study. At the end of the study animals were given an intraperitoneal glucose tolerance test. Animals were then culled and blood and tissues were collected for analysis. Insulin and glucagon contents of plasma and tissues were measured by insulin radioimmunoassay and chemiluminescent enzyme-linked immunosorbance assay respectively. Histological analyses of pancreatic islets were carried out by quantitative fluorescence immunohistochemistry staining.
RESULTS Both pseudoislet and cell suspension implants yielded well vascularised β-cell masses of similar insulin content. This was associated with progressive amelioration of hyperphagia (P < 0.05), polydipsia (P < 0.05), body weight loss (P < 0.05), hypoinsulinaemia (P < 0.05), hyperglycaemia (P < 0.05 - P < 0.001) and glucose tolerance (P < 0.01). Islet morphology was also significantly improved in both groups of transplanted mice, with increased β-cell (P < 0.05 - P < 0.001) and decreased alpha cell (P < 0.05 - P < 0.001) areas. Whereas mice receiving 1.1B4 cell suspensions eventually exhibited hypoglycaemic complications, pseudoislet recipients displayed a more gradual amelioration of diabetes, and achieved stable blood glucose control similar to non-diabetic mice at the end of the study.
CONCLUSION Although further work is needed to address safety issues, these results provide proof of concept for possible therapeutic applicability of human β-cell line pseudoislets in diabetes.
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Pawlick RL, Wink J, Pepper AR, Bruni A, Abualhassen N, Rafiei Y, Gala-Lopez B, Bral M, Shapiro AJ. Reparixin, a CXCR1/2 inhibitor in islet allotransplantation. Islets 2016; 8:115-24. [PMID: 27328412 PMCID: PMC5029202 DOI: 10.1080/19382014.2016.1199303] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Quality of life in Type 1 diabetic patients may be improved with islet transplantation, but lifelong immunosuppression is required to prevent rejection. Allo-immune response is a key player in graft dysfunction and although the adaptive immune response is well characterized, the effect of the innate immune reaction after transplantation is only recently becoming appreciated. In this study, we address how the innate response affects long-term outcomes in a murine islet allotransplant model. CTLA-4 Ig treatment is known to significantly prolong kidney subcapsular islet allograft survival and enhance glucose tolerance. The combination of CTLA-4 Ig with reparixin, which blocks against inflammatory neutrophil infiltration, yielded no long-term graft survival in an intrahepatic allotransplant model but had similar long-term graft survival in the kidney subcapsular model. Seven days after transplant, serum blood IFN-γ levels were significantly lower in the CTLA-4 Ig with reparixin treatment group compared to controls. IL-12p70 cytokine levels were increased with combination treatment, a positive modulation of the inflammatory response to the allograft. Furthermore, KC GRO, also known as CXCL1, was decreased in serum 7 d after transplant. Histologically, we found that immune cell infiltrate, CD4+ and CD8+ T cell populations along with both CXCR1+ and CXCR2+ cell populations were decreased within the CTLA-4 Ig and reparixin islet transplant graft. Overall these data provide insight into the down regulation of T-cell recruitment by CTLA-4 Ig and decreased neutrophil activation and recruitment with reparixin after long-term islet graft survival.
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Affiliation(s)
- Rena L. Pawlick
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - John Wink
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Andrew R. Pepper
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Antonio Bruni
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | | | - Yasmin Rafiei
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Boris Gala-Lopez
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Mariusz Bral
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - A.M. James Shapiro
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Clinical Islet Transplant Program, University of Alberta, Edmonton, AB, Canada
- CONTACT: Dr. A.M. James Shapiro , Canada Research Chair in Transplantation Surgery and Regenerative Medicine, 2000 College Plaza, 8215 112th St., Edmonton, AB, Canada T6G 2C8
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Wallner K, Shapiro AMJ, Senior PA, McCabe C. Cost effectiveness and value of information analyses of islet cell transplantation in the management of 'unstable' type 1 diabetes mellitus. BMC Endocr Disord 2016; 16:17. [PMID: 27061400 PMCID: PMC4826503 DOI: 10.1186/s12902-016-0097-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/22/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Islet cell transplantation is a method to stabilize type 1 diabetes patients with hypoglycemia unawareness and unstable blood glucose levels by reducing insulin dependency and protecting against severe hypoglycemia through restoring endogenous insulin secretion. This study analyses the current cost-effectiveness of this technology and estimates the value of further research to reduce uncertainty around cost-effectiveness. METHODS We performed a cost-utility analysis using a Markov cohort model with a mean patient age of 49 to simulate costs and health outcomes over a life-time horizon. Our analysis used intensive insulin therapy (IIT) as comparator and took the provincial healthcare provider perspective. Cost and effectiveness data for up to four transplantations per patient came from the University of Alberta hospital. Costs are expressed in 2012 Canadian dollars and effectiveness in quality-adjusted life-years (QALYs) and life years. To characterize the uncertainty around expected outcomes, we carried out a probabilistic sensitivity analysis within the Bayesian decision-analytic framework. We performed a value-of-information analysis to identify priority areas for future research under various scenarios. We applied a structural sensitivity analysis to assess the dependence of outcomes on model characteristics. RESULTS Compared to IIT, islet cell transplantation using non-generic (generic) immunosuppression had additional costs of $150,006 ($112,023) per additional QALY, an average gain of 3.3 life years, and a probability of being cost-effective of 0.5 % (28.3 %) at a willingness-to-pay threshold of $100,000 per QALY. At this threshold the non-generic technology has an expected value of perfect information (EVPI) of $260,744 for Alberta. This increases substantially in cost-reduction scenarios. The research areas with the highest partial EVPI are costs, followed by natural history, and effectiveness and safety. CONCLUSIONS Current transplantation technology provides substantial improvements in health outcomes over conventional therapy for highly selected patients with 'unstable' type 1 diabetes. However, it is much more costly and so is not cost-effective. The value of further research into the cost-effectiveness is dependent upon treatment costs. Further, we suggest the value of information should not only be derived from current data alone when knowing that this data will most likely change in the future.
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Affiliation(s)
- Klemens Wallner
- />Department of Emergency Medicine, University of Alberta, 736 University Terrace Building, 8303 - 112 Street, Edmonton, AB T6G 2T4 Canada
| | - A. M. James Shapiro
- />Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB T6G 2C8 Canada
- />Department of Surgery, University of Alberta, Edmonton, AB Canada
| | - Peter A. Senior
- />Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, 2000 College Plaza, 8215 - 112 Street, Edmonton, AB T6G 2C8 Canada
- />Division of Endocrinology and Metabolism, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Christopher McCabe
- />Department of Emergency Medicine, University of Alberta, 736 University Terrace Building, 8303 - 112 Street, Edmonton, AB T6G 2T4 Canada
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Copelan A, George D, Kapoor B, Nghiem HV, Lorenz JM, Erly B, Wang W. Iatrogenic-related transplant injuries: the role of the interventional radiologist. Semin Intervent Radiol 2015; 32:133-55. [PMID: 26038621 DOI: 10.1055/s-0035-1549842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As advances in surgical techniques and postoperative care continue to improve outcomes, the use of solid organ transplants as a treatment for end-stage organ disease is increasing. With the growing population of transplant patients, there is an increasing need for radiologic diagnosis and minimally invasive procedures for the management of posttransplant complications. Typical complications may be vascular or nonvascular. Vascular complications include arterial stenosis, graft thrombosis, and development of fistulae. Common nonvascular complications consist of leaks, abscess formation, and stricture development. The use of interventional radiology in the management of these problems has led to better graft survival and lower patient morbidity and mortality. An understanding of surgical techniques, postoperative anatomy, radiologic findings, and management options for complications is critical for proficient management of complex transplant cases. This article reviews these factors for kidney, liver, pancreas, islet cell, lung, and small bowel transplants.
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Affiliation(s)
- Alexander Copelan
- Department of Diagnostic Radiology, William Beaumont Hospital, Royal Oak, Michigan
| | - Daniel George
- Department of Diagnostic Radiology, William Beaumont Hospital, Royal Oak, Michigan
| | - Baljendra Kapoor
- Section of Interventional Radiology, Imaging Institute, Cleveland Clinic, Cleveland, Ohio
| | - Hahn Vu Nghiem
- Department of Diagnostic Radiology, William Beaumont Hospital, Royal Oak, Michigan
| | - Jonathan M Lorenz
- Section of Interventional Radiology, The University of Chicago, Chicago, Illinois
| | - Brian Erly
- Section of Interventional Radiology, Imaging Institute, Cleveland Clinic, Cleveland, Ohio ; Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Weiping Wang
- Section of Interventional Radiology, Imaging Institute, Cleveland Clinic, Cleveland, Ohio
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Mathiyalagan P, Keating ST, Al-Hasani K, El-Osta A. Epigenetic-mediated reprogramming of pancreatic endocrine cells. Antioxid Redox Signal 2015; 22:1483-95. [PMID: 25621632 DOI: 10.1089/ars.2014.6103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE Type 1 diabetes (T1D) results from cell-mediated autoimmune destruction of insulin-secreting pancreatic beta cells (β-cells). In the context of T1D, the scarcity of organ donors has driven research to alternate sources of functionally competent, insulin-secreting β-cells as substitute for donor islets to meet the clinical need for transplantation therapy. RECENT ADVANCES Experimental evidence of an inherent plasticity of pancreatic cells has fuelled interest in in vivo regeneration of β-cells. Transcriptional modulation and direct reprogramming of noninsulin secreting pancreatic α-cells to functionally mimic insulin-secreting β-cells is one of the promising avenues to the treatment of diabetes. Recent studies now show that adult progenitor and glucagon(+) α-cells can be converted into β-like cells in vivo, as a result of specific activation of the Pax4 gene in α-cells and curing diabetes in preclinical models. CRITICAL ISSUES The challenge now is to understand the precise developmental transitions mediated by endocrine transcription factors and co-regulatory determinants responsible for pancreatic function and repair. FUTURE DIRECTIONS Epigenetic-mediated regulation of transcription factor binding in pancreatic α-cells by specific drugs to direct reprogramming into functional insulin producing cells could be of potential innovative therapy for the treatment of T1D.
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Affiliation(s)
- Prabhu Mathiyalagan
- 1 Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct , Melbourne, Australia
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Glucose-driven chemo-mechanical autonomous drug-release system with multi-enzymatic amplification toward feedback control of blood glucose in diabetes. Biosens Bioelectron 2015; 67:315-20. [PMID: 25223550 DOI: 10.1016/j.bios.2014.08.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/11/2014] [Accepted: 08/14/2014] [Indexed: 01/27/2023]
Abstract
A second-generation novel chemo-mechanical autonomous drug release system, incorporating various improvements over our first-generation system, was fabricated and evaluated. Enhanced oxygen uptake by the enzyme membrane of the organic engine was facilitated by optimizing the quantity of enzyme immobilizer, PVA-SbQ, and by hydrophobizing the membrane surface. Various quantities of PVA-SbQ were evaluated in the organic engine by measuring the decompression rate, with 1.5 mg/cm(2) yielding optimum results. When fluororesin was used as a hydrophobizing coating, the time to reach the peak decompression rate was shortened 2.3-fold. The optimized elements of the system were evaluated as a unit, first in an open loop and then in a closed loop setting, using a mixture of glucose solution (25 mmol/L), ATP and MgCI2 with glucose hexokinase enzyme (HK) as a glucose reducer. In conclusion, feedback-control of physiologically relevant glucose concentration was demonstrated by the second-generation drug release system without any requirement for external energy.
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Kuehn C, Fülöp T, Lakey JRT, Vermette P. Young porcine endocrine pancreatic islets cultured in fibrin and alginate gels show improved resistance towards human monocytes. ACTA ACUST UNITED AC 2014; 62:354-64. [PMID: 25239278 DOI: 10.1016/j.patbio.2014.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 07/29/2014] [Indexed: 12/17/2022]
Abstract
AIM To investigate the protective function of alginate and fibrin gels used to embed porcine endocrine pancreatic islets towards human monocytes. METHODS Groups of 200 islet equivalents from young pigs were embedded in either a fibrin or in an alginate gel, and as a control seeded in tissue culture polystyrene (TCPS) well plates. The islet cultures were incubated with 2×10(5) human monocytes for 24h. In addition, both islets and monocytes were separately cultured in TCPS, fibrin and alginate. Islet morphology, viability and function were investigated as well as the secretion of cytokines TNFα, IL-6, and IL-1β. RESULTS When freely-floating in TCPS, non-encapsulated islets were surrounded by monocytes and started to disperse after 24h. In fibrin, monocytes could be found in close proximity to embedded islets, indicating monocyte migration through the gel. In contrast, after 24h, few monocytes were found close to islets in alginate. Immunofluorescence staining and manual counting showed that integrin expression was higher in fibrin-embedded islet cultures. A TUNEL assay revealed elevated numbers of apoptotic cells for islets in TCPS wells compared to fibrin and alginate cultures. Insulin secretion was higher with islets embedded in fibrin and alginate when compared to non-encapsulated islets. TNFα, IL-6 and IL-1β were found in high concentrations in the media of co-cultures and monocyte mono-culture in fibrin. CONCLUSION Both alginate and fibrin provide key structural support and offer some protection for the islets towards human monocytes. Fibrin itself triggers the cytokine secretion from monocytes.
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Affiliation(s)
- C Kuehn
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500, boulevard de l'Université, J1K 2R1 Sherbrooke, Québec, Canada; Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036, rue Belvédère Sud, J1H 4C4 Sherbrooke, Québec, Canada
| | - T Fülöp
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036, rue Belvédère Sud, J1H 4C4 Sherbrooke, Québec, Canada
| | - J R T Lakey
- Department of Surgery and Biomedical Engineering, University of California, Irvine, 333 City Boulevard West, Suite 700, Orange, 92868 CA, United States
| | - P Vermette
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500, boulevard de l'Université, J1K 2R1 Sherbrooke, Québec, Canada; Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036, rue Belvédère Sud, J1H 4C4 Sherbrooke, Québec, Canada.
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