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Šterk M, Zhang Y, Pohorec V, Leitgeb EP, Dolenšek J, Benninger RKP, Stožer A, Kravets V, Gosak M. Network representation of multicellular activity in pancreatic islets: Technical considerations for functional connectivity analysis. PLoS Comput Biol 2024; 20:e1012130. [PMID: 38739680 PMCID: PMC11115366 DOI: 10.1371/journal.pcbi.1012130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/23/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
Within the islets of Langerhans, beta cells orchestrate synchronized insulin secretion, a pivotal aspect of metabolic homeostasis. Despite the inherent heterogeneity and multimodal activity of individual cells, intercellular coupling acts as a homogenizing force, enabling coordinated responses through the propagation of intercellular waves. Disruptions in this coordination are implicated in irregular insulin secretion, a hallmark of diabetes. Recently, innovative approaches, such as integrating multicellular calcium imaging with network analysis, have emerged for a quantitative assessment of the cellular activity in islets. However, different groups use distinct experimental preparations, microscopic techniques, apply different methods to process the measured signals and use various methods to derive functional connectivity patterns. This makes comparisons between findings and their integration into a bigger picture difficult and has led to disputes in functional connectivity interpretations. To address these issues, we present here a systematic analysis of how different approaches influence the network representation of islet activity. Our findings show that the choice of methods used to construct networks is not crucial, although care is needed when combining data from different islets. Conversely, the conclusions drawn from network analysis can be heavily affected by the pre-processing of the time series, the type of the oscillatory component in the signals, and by the experimental preparation. Our tutorial-like investigation aims to resolve interpretational issues, reconcile conflicting views, advance functional implications, and encourage researchers to adopt connectivity analysis. As we conclude, we outline challenges for future research, emphasizing the broader applicability of our conclusions to other tissues exhibiting complex multicellular dynamics.
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Affiliation(s)
- Marko Šterk
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Yaowen Zhang
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Viljem Pohorec
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Jurij Dolenšek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Richard K. P. Benninger
- Department of Bioengineering, Barbara Davis Center for Diabetes, Aurora, Colorado, United States of America
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Vira Kravets
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, Jacobs School of Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Alma Mater Europaea, Maribor
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Brandhorst H, Johnson PR, Mönch J, Kurfürst M, Korsgren O, Brandhorst D. Comparison of Clostripain and Neutral Protease as Supplementary Enzymes for Human Islet Isolation. Cell Transplant 2018; 28:176-184. [PMID: 30419762 PMCID: PMC6362525 DOI: 10.1177/0963689718811614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Although human islet transplantation has been established as valid and safe treatment for patients with type 1 diabetes, the utilization rates of human pancreases for clinical islet transplantation are still limited and substantially determined by the quality and composition of collagenase blends. While function and integrity of collagenase has been extensively investigated, information is still lacking about the most suitable supplementary neutral proteases. The present study compared islet isolation outcome after pancreas digestion by means of collagenase used alone or supplemented with either neutral protease (NP), clostripain (CP), or both proteases. Decent amounts of islet equivalents (IEQ) were isolated using collagenase alone (3090 ± 550 IEQ/g), or in combination with NP (2340 ± 450 IEQ/g) or CP (2740 ± 280 IEQ/g). Nevertheless, the proportion of undigested tissue was higher after using collagenase alone (21.1 ± 1.1%, P < 0.05) compared with addition of NP (13.3 ± 2.2%) or CP plus NP (13.7 ± 2.6%). Likewise, the percentage of embedded islets was highest using collagenase only (13 ± 2%) and lowest adding NP plus CP (4 ± 1%, P < 0.01). The latter combination resulted in lowest post-culture overall survival (42.7 ± 3.9%), while highest survival was observed after supplementation with CP (74.5 ± 4.8%, P < 0.01). An insulin response toward glucose challenge was present in all experimental groups, but the stimulation index was significantly decreased using collagenase plus NP (2.0 ± 0.12) compared with supplementation with CP (3.16 ± 0.4, P < 0.001). This study demonstrates for the first time that it is possible to isolate significant numbers of human islets combining collagenase only with CP. The supplementation with CP is an effective means to substantially reduce NP activity, which significantly decreases survival and viability after culture. This will facilitate the manufacturing of enzyme blends with less harmful characteristics.
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Affiliation(s)
- Heide Brandhorst
- 1 Nuffield Department of Surgical Sciences, University of Oxford, UK.,2 Oxford Centre for Diabetes, Endocrinology and Metabolism, UK.,3 Department of Immunology, Genetics and Pathology, University of Uppsala, Sweden
| | - Paul R Johnson
- 1 Nuffield Department of Surgical Sciences, University of Oxford, UK.,2 Oxford Centre for Diabetes, Endocrinology and Metabolism, UK.,4 Oxford NIHR Biomedical Research Centre, UK
| | | | | | - Olle Korsgren
- 3 Department of Immunology, Genetics and Pathology, University of Uppsala, Sweden
| | - Daniel Brandhorst
- 1 Nuffield Department of Surgical Sciences, University of Oxford, UK.,2 Oxford Centre for Diabetes, Endocrinology and Metabolism, UK.,3 Department of Immunology, Genetics and Pathology, University of Uppsala, Sweden
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3
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Abstract
PURPOSE OF REVIEW Porcine islets are being extensively investigated as alternative sources of insulin-secreting cells for transplantation in insulin-dependent diabetic patients. The present review focuses on recent advances in porcine islet transplantation with particular emphasis on new transgenic pig models, islet encapsulation, and biosafety considerations. RECENT FINDINGS Genetic modifications aimed to reduce islet cell immunogenicity, to prolong their survival, and to improve their secretory function have been reported. Micro- and macroencapsulation of porcine islets should allow their use in the clinic with no or minimal immunosuppression. The risk of porcine endogenous retrovirus transmission is being re-evaluated since no evidence for infection was found in several clinical and preclinical studies. SUMMARY Pig islet xenotransplantation is still a serious contestant in the race for novel treatments for type I diabetes. Adequate pathogen screening, animal selection, and the establishment of microbiological, genetic, and potency release quality controls should increase safety and efficacy of future porcine islets transplantation clinical trials.
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Brandhorst D, Brandhorst H, Johnson PRV. Enzyme Development for Human Islet Isolation: Five Decades of Progress or Stagnation? Rev Diabet Stud 2017. [PMID: 28632819 DOI: 10.1900/rds.2017.14.22] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In comparison to procedures used for the separation of individual cell types from other organs, the process of human pancreatic islet isolation aims to digest the pancreatic exocrine matrix completely without dispersing the individual cells within the endocrine cell cluster. This objective is unique within the field of tissue separation, and outlines the challenge of islet isolation to balance two opposing priorities. Although significant progress has been made in the characterization and production of enzyme blends for islet isolation, there are still numerous areas which require improvement. The ultimate goal of enzyme production, namely the routine production of a consistent and standardized enzyme blend, has still not been realized. This seems to be mainly the result of a lack of detailed knowledge regarding the structure of the pancreatic extracellular matrix and the synergistic interplay between collagenase and different supplementary proteases during the degradation of the extracellular matrix. Furthermore, the activation of intrinsic proteolytic enzymes produced by the pancreatic acinar cells, also impacts on the chance of a successful outcome of human islet isolation. This overview discusses the challenges of pancreatic enzymatic digestion during human islet isolation, and outlines the developments in this field over the past 5 decades.
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Affiliation(s)
- Daniel Brandhorst
- Nuffield Department of Surgical Sciences, University of Oxford, United Kingdom
| | - Heide Brandhorst
- Nuffield Department of Surgical Sciences, University of Oxford, United Kingdom
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, United Kingdom
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Truong W, Shapiro AMJ. Progress in islet transplantation in patients with type 1 diabetes mellitus. ACTA ACUST UNITED AC 2016; 5:147-58. [PMID: 16677057 DOI: 10.2165/00024677-200605030-00003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
More than 500 patients with type 1 diabetes mellitus have now received islet transplants at over 50 institutions worldwide in the past 5 years. Rates of insulin independence at 1 year with current protocols are impressive. However, inexorable decay of islet function over time indicates that there are many opportunities for improvement. Improved control of glycosylated hemoglobin and reduced risk of recurrent hypoglycemia are seen as important benefits of islet transplantation, irrespective of the status regarding insulin independence. For the use of islet transplantation to expand it is essential that the donor-to-recipient ratio be reliably reduced to 1 : 1. Enormous opportunities lie ahead for the development of successful living donor islet transplantation, single donor protocols, improved engraftment, islet proliferation in vitro and in the recipient, alternative islet sources, and novel tolerizing drugs. With these emerging opportunities, islet transplantation may expand to include more patients with type 1 diabetes, including children, and will not be restricted to the most unstable forms of the disease, as it is today.
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Affiliation(s)
- Wayne Truong
- Department of Surgery, Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Hawthorne WJ, Williams L, Chew YV. Clinical Islet Isolation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 938:89-122. [PMID: 27586424 DOI: 10.1007/978-3-319-39824-2_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The overarching success of islet transplantation relies on the success in the laboratory to isolate the islets. This chapter focuses on the processes of human islet cell isolation and the ways to optimally provide islet cells for transplantation. The major improvements in regards to the choice of enzyme type, way the digested pancreas tissue is handled to best separate islets from the acinar and surrounding tissues, the various methods of purification of the islets, their subsequent culture and quality assurance to improve outcomes to culminate in safe and effective islet transplantation will be discussed. After decades of improvements, islet cell isolation and transplantation now clearly offer a safe, effective and feasible therapeutic treatment option for an increasing number of patients suffering from type 1 diabetes specifically for those with severe hypoglycaemic unawareness.
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Affiliation(s)
- Wayne J Hawthorne
- National Pancreas and Islet Transplant Laboratories, The Westmead Institute for Medical Research, Westmead, NSW, 2145, Australia. .,Department of Surgery, Westmead Clinical School, Westmead Hospital, University of Sydney, Westmead, NSW, 2145, Australia.
| | - Lindy Williams
- National Pancreas and Islet Transplant Laboratories, The Westmead Institute for Medical Research, Westmead, NSW, 2145, Australia
| | - Yi Vee Chew
- National Pancreas and Islet Transplant Laboratories, The Westmead Institute for Medical Research, Westmead, NSW, 2145, Australia
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Affiliation(s)
- Federico Bertuzzi
- The Meditterranean Institute for Transplantation and Advanced Specialized Therapies, via Tricomi 1, Palermo, Italy.
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Korsgren O, Nilsson B, Berne C, Felldin M, Foss A, Kallen R, Lundgren T, Salmela K, Tibell A, Tufveson G. Current status of clinical islet transplantation. Transplantation 2005; 79:1289-93. [PMID: 15912090 DOI: 10.1097/01.tp.0000157273.60147.7c] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Islet transplantation is currently being explored as a treatment for patients with type 1 diabetes. At present, the number of patients becoming insulin-independent is rapidly increasing world-wide applying the transplantation protocol originally described by the group in Edmonton. A hallmark in this procedure is repeated infusions of islets obtained from 2 to 4 donors until normoglycemia is achieved. In order to establish islet transplantation as a widely accepted treatment modality, and make tolerance induction regimes applicable, it is essential that the donor:recipient ratio is brought down to 1:1. A conceivable strategy to achieve this goal in clinical islet transplantation is discussed.
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Affiliation(s)
- Olle Korsgren
- Department of Radiology, Oncology and Clinical Immunology, Division of Clinical Immunology, The Rudbeck Laboratory, University Hospital, Uppsala, Sweden.
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Nano R, Clissi B, Melzi R, Calori G, Maffi P, Antonioli B, Marzorati S, Aldrighetti L, Freschi M, Grochowiecki T, Socci C, Secchi A, Di Carlo V, Bonifacio E, Bertuzzi F. Islet isolation for allotransplantation: variables associated with successful islet yield and graft function. Diabetologia 2005; 48:906-12. [PMID: 15830183 DOI: 10.1007/s00125-005-1725-3] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 01/04/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Efficient islet isolation is an important prerequisite for successful clinical islet transplantation. Although progressively improved, islet yield and quality are, however, unpredictable and variable and require standardisation. METHODS Since 1989 we have processed 437 pancreases using the automated method. The donor characteristics, pancreas procurement, and digestion and purification procedures including a wide enzyme characterisation of these pancreases were analysed and correlated with islet yield and transplant outcome. RESULTS By univariate analysis, islet yield was significantly associated with donor age (r=0.16; p=0.0009), BMI (r=0.19; p=0.0004), good pancreas condition (p=0.0031) and weight (r=0.15; p=0.0056), total collagenase activity (r=0.22; p=0.0001), adjusted collagenase activity/mg (r=0.18; p=0.0002), collagenase activity/solution volume (r=0.18; p=0.0002) and neutral protease activity/solution volume (r=0.14; p=0.0029). A statistically significant contribution to the variability of islet yield in a multivariate analysis performed on donor variables was found for donor BMI (p=0.0008). In a multivariate analysis performed on pancreas variables a contribution was found for pancreas weight (p=0.0064), and for a multivariate analysis performed on digestion variables we found a contribution for digestion time (p=0.0048) and total collagenase activity (p=0.0001). Twenty-four patients with type 1 diabetes received single islet preparations from single donors. In these patients, multivariate analyses showed that the reduction in insulin requirement was significantly associated with morphological aspects of islets (p=0.0010) and that 1-month C-peptide values were associated with islet purity (p=0.0071). CONCLUSIONS/INTERPRETATION These data provide baseline donor, digestion and purification selection criteria for islet isolation using the automated method and indicate that the morphological aspect may be a clinically relevant measure of islets on which the decision for transplant can be based.
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Affiliation(s)
- R Nano
- Medicine and Surgical Departments, S. Raffaele Scientific Institute, Via Olgettina 60, Milan, Italy.
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Matsumoto S, Rigley TH, Reems JA, Kuroda Y, Stevens RB. Improved islet yields from Macaca nemestrina and marginal human pancreata after two-layer method preservation and endogenous trypsin inhibition. Am J Transplant 2003; 3:53-63. [PMID: 12492711 DOI: 10.1034/j.1600-6143.2003.30110.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We tested whether two-layer method (TLM) pancreas preservation and trypsin inhibition (Pefabloc) during processing allows longer preservation while retaining or improving viable islet recovery. Non-marginal primate (Macaca nemestrina) and marginal human (ischemic or preservation-injured) pancreata were processed with a research-oriented pan technique (Seattle method). Organs were processed upon arrival (+/- Pefabloc), or after TLM or University of Wisconsin solution (UW) preservation (+ Pefabloc). Islet yield, viability, and function were assessed. Pefabloc increased M. nemestrina islet yields from 9696 +/- 1749 IE/g to 15 822 +/- 1332 IE/g (p < 0.01). Two-layer method preservation (< 6 h) further increased yields, to 23 769 +/- 2773 IE/g (vs. + Pefabloc; p < 0.01). Similarly, Pefabloc increased marginal human islet yields from 2473 +/- 472 IE/g to 4723 +/- 1006 IE/g (p < 0.04). This increase was maintained after lengthy TLM preservation (> 30 h; 4801 +/- 1066 IE/g). We also tested the applicability of TLM preservation (23.5 +/- 3.2 h) to the processing of marginal human pancreata by the Edmonton/Immune Tolerance Network clinical protocol. Islet yield and function approached published results of pancreata processed 4.8 +/- 0.8 h after organ recovery (p = 0.06). Pefabloc, and TLM vs. UW preservation, prolonged the tolerable interval between organ recovery and islet isolation. Islet yield, viability, and functionality improved from both marginal and nonmarginal pancreata.
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Yang TY, Oh SH, Jeong IK, Seo IA, Oh EY, Kim SJ, Chung JH, Min YK, Lee MS, Lee MK, Kim KW, Do YS, Choo SW. First human trial of pancreatic islet allo-transplantation in Korea--focus on re-transplantation. Diabetes Res Clin Pract 2002; 56:107-13. [PMID: 11891018 DOI: 10.1016/s0168-8227(01)00366-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Over the past 20 years, allo-transplantation of islet or whole pancreas for reaching and sustaining near-normoglycemia, as close as possible to the physiological model, have been undertaken. As previously known, even though islet transplantation is possible as a safe re-transplant, it is not well known whether re-transplantation of islets is suitable for patients who have lost the grafted islet function. We have performed a human islet allo-transplantation and re-transplantation on an IDDM patient for the first time in Asia and Korea. The recipient was a 32-year-old male and his insulin requirement was 75-85 U per day. After islet transplantation, the basal C-peptide increased from 0.6 to 2.1 ng/ml and insulin requirement decreased from 80 to 36 U per day, indicating that the grafted islets were functional. However, the grafted islets lost function 70 days after the transplantation. So, we performed re-transplantation of the islets. After the re-transplantation, the glucose profile became more stable and frequent episodes of severe hypoglycemia completely disappeared. His severe neuropathic pain improved dramatically and he could engage his ordinary daily life without any antineuropathic drugs. The success of this re-transplantation is one step closer to becoming a viable alternative for the millions of individuals who are suffering from diabetes.
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Affiliation(s)
- Tae-Young Yang
- Department of Medicine, Division of Endocrinology and Metabolism, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, South Korea
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Sabat M, Godlewska E, Sitarek E, Orłowski T. Effects of encapsulation on in vitro function of cryopreserved rat islets. Transplant Proc 2002; 34:651-2. [PMID: 12009652 DOI: 10.1016/s0041-1345(01)02875-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- M Sabat
- Institute of Biocybernetics and Biochemical Engineering, Polish Academy of Science, Warsaw, Poland
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