scholarly journals Calcium

2018 ◽  
Vol 27 (7) ◽  
pp. 1031-1038 ◽  
Author(s):  
Torsten Eich ◽  
Magnus Ståhle ◽  
Bengt Gustafsson ◽  
Rune Horneland ◽  
Marko Lempinen ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Islet Transplantation ◽  
Clinical Chemistry ◽  
Pancreatic Enzyme ◽  
Human Islets ◽  
Human Pancreas ◽  
Islet Isolation ◽  
Clinical Islet Transplantation ◽  
The Media ◽  
Major Reduction

Background: Effective digestive enzymes are crucial for successful islet isolation. Supplemental proteases are essential because they synergize with collagenase for effective pancreatic digestion. The activity of these enzymes is critically dependent on the presence of Ca2+ ions at a concentration of 5–10 mM. The present study aimed to determine the Ca2+ concentration during human islet isolation and to ascertain whether the addition of supplementary Ca2+ is required to maintain an optimal Ca2+ concentration during the various phases of the islet isolation process. Methods: Human islets were isolated according to standard methods and isolation parameters. Islet quality control and the number of isolations fulfilling standard transplantation criteria were evaluated. Ca2+ was determined by using standard clinical chemistry routines. Islet isolation was performed with or without addition of supplementary Ca2+ to reach a Ca2+ of 5 mM. Results: Ca2+ concentration was markedly reduced in bicarbonate-based buffers, especially if additional bicarbonate was used to adjust the pH as recommended by the Clinical Islet Transplantation Consortium. A major reduction in Ca2+ concentration was also observed during pancreatic enzyme perfusion, digestion, and harvest. Additional Ca2+ supplementation of media used for dissolving the enzymes and during digestion, perfusion, and harvest was necessary in order to obtain the concentration recommended for optimal enzyme activity and efficient liberation of a large number of islets from the human pancreas. Conclusions: Ca2+ is to a large extent consumed during clinical islet isolation, and in the absence of supplementation, the concentration fell below that recommended for optimal enzyme activity. Ca2+ supplementation of the media used during human pancreas digestion is necessary to maintain the concentration recommended for optimal enzyme activity. Addition of Ca2+ to the enzyme blend has been implemented in the standard isolation protocols in the Nordic Network for Clinical Islet Transplantation.

scholarly journals Comparison of Clostripain and Neutral Protease as Supplementary Enzymes for Human Islet Isolation

2018 ◽  
Vol 28 (2) ◽  
pp. 176-184 ◽  
Author(s):  
Heide Brandhorst ◽  
Paul R. Johnson ◽  
Johanna Mönch ◽  
Manfred Kurfürst ◽  
Olle Korsgren ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Stimulation Index ◽  
Effective Means ◽  
Insulin Response ◽  
Human Islets ◽  
Human Islet ◽  
Neutral Protease ◽  
Islet Isolation ◽  
Clinical Islet Transplantation ◽  
Glucose Challenge

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.

Endogenous Pancreatic Enzyme Activity Levels Show no Significant Effect on Human Islet Isolation Yield

2004 ◽  
Vol 13 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Natisha L. Rose ◽  
Monica M. Palcic ◽  
A. M. James Shapiro ◽  
Jonathan R. T. Lakey
Keyword(s):  
Enzyme Activity ◽  
Pancreatic Enzyme ◽  
Human Islet ◽  
Activity Levels ◽  
Islet Isolation

scholarly journals Anakinra and Tocilizumab Enhance Survival and Function of Human Islets during Culture: Implications for Clinical Islet Transplantation

2014 ◽  
Vol 23 (10) ◽  
pp. 1199-1211 ◽  
Author(s):  
Afaf Sahraoui ◽  
Kristine Kloster-Jensen ◽  
Thor Ueland ◽  
Olle Korsgren ◽  
Aksel Foss ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Glycosylated Hemoglobin ◽  
Human Islets ◽  
Diabetic Patients ◽  
Β Cells ◽  
Mass Model ◽  
Immunodeficient Mice ◽  
Markers Of Inflammation ◽  
Clinical Islet Transplantation ◽  
The Impact

Pretreatment culture before islet transplantation represents a window of opportunity to ameliorate the pro-inflammatory profile expressed by human β-cells in duress. Anakinra (IL-1 receptor antagonist) and tocilizumab (monoclonal IL-6 receptor antibody) are two known anti-inflammatory agents successfully used in the treatment of inflammatory states like rheumatoid arthritis. Both compounds have also been shown to reduce blood glucose and glycosylated hemoglobin in diabetic patients. We therefore sought to evaluate the impact of anakinra and tocilizumab on human β-cells. The islets were precultured with or without anakinra or tocilizumab and then transplanted in a marginal mass model using human islets in immunodeficient mice. Islet viability was evaluated in an in vitro model. The pretreatment culture led to a significantly improved engraftment in treated islets compared to the vehicle. Anakinra and tocilizumab are not toxic to human islets and significantly reduce markers of inflammation and cell death. These results strongly support a pretreatment culture with anakinra and tocilizumab prior to human islet transplantation.

scholarly journals Comparison of Trypsin Inhibitors in Preservation Solution for Islet Isolation

2009 ◽  
Vol 18 (5-6) ◽  
pp. 541-548 ◽  
Author(s):  
Hirofumi Noguchi ◽  
Michiko Ueda ◽  
Shuji Hayashi ◽  
Naoya Kobayashi ◽  
Teru Okitsu ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Stimulation Index ◽  
Islet Isolation ◽  
Preservation Solution ◽  
University Of Wisconsin ◽  
Trypsin Inhibition ◽  
Clinical Islet Transplantation ◽  
Pancreas Preservation ◽  
Collagenase Inhibition

Islet transplantation has recently emerged as an effective therapy and potential cure for type 1 diabetes mellitus. Recent reports show that the two-layer method (TLM), which employs oxygenated perfluorochemical (PFC) and University of Wisconsin (UW) solution, is superior to simple cold storage in UW for pancreas preservation in islet transplantation. Moreover, we recently reported that islet yield was significantly higher in the ET-Kyoto solution with ulinastatin (MK)/PFC preservation solution compared with the UW/PFC preservation solution in the porcine model and that the advantages of MK solution are trypsin inhibition and less collagenase inhibition. In this study, we compared ulinastatin with another trypsin inhibitor, Pefabloc, in preservation solution for islet isolation. Islet yield before purification was higher in the MK/PFC group compared with the ET-Kyoto with Pefabloc (PK)/PFC group. The stimulation index was higher for the MK/PFC group than for the PK/PFC group. These data suggest that ET-Kyoto with ulinastatin was the better combination for pancreas preservation than ET-Kyoto with Pefabloc. Based on these data, we now use ET-Kyoto solution with ulinastatin for clinical islet transplantation.

scholarly journals Pancreas-on-a-Chip Technology for Transplantation Applications

2020 ◽  
Vol 20 (12) ◽  
Author(s):  
Shadab Abadpour ◽  
Aleksandra Aizenshtadt ◽  
Petter Angell Olsen ◽  
Kayoko Shoji ◽  
Steven Ray Wilson ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Islet Function ◽  
Human Pancreas ◽  
Animal Testing ◽  
Microfluidic Platforms ◽  
Chip Technology ◽  
Clinical Islet Transplantation ◽  
Islet Physiology

Abstract Purpose of Review Human pancreas-on-a-chip (PoC) technology is quickly advancing as a platform for complex in vitro modeling of islet physiology. This review summarizes the current progress and evaluates the possibility of using this technology for clinical islet transplantation. Recent Findings PoC microfluidic platforms have mainly shown proof of principle for long-term culturing of islets to study islet function in a standardized format. Advancement in microfluidic design by using imaging-compatible biomaterials and biosensor technology might provide a novel future tool for predicting islet transplantation outcome. Progress in combining islets with other tissue types gives a possibility to study diabetic interventions in a minimal equivalent in vitro environment. Summary Although the field of PoC is still in its infancy, considerable progress in the development of functional systems has brought the technology on the verge of a general applicable tool that may be used to study islet quality and to replace animal testing in the development of diabetes interventions.

scholarly journals The Effects of Using Pancreases Obtained from Brain-Dead Donors for Clinical Islet Transplantation in Japan

2019 ◽  
Vol 8 (9) ◽  
pp. 1430
Author(s):  
Taihei Ito ◽  
Takashi Kenmochi ◽  
Kei Kurihara ◽  
Akihiro Kawai ◽  
Naohiro Aida ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Pancreatic Islet ◽  
Islet Isolation ◽  
Heart Beating ◽  
Clinical Islet Transplantation ◽  
Significant Difference ◽  
Brain Dead ◽  
Islet Transplants

Background: The pool of brain-dead donors (BDDs) was increased with the revision to the relevant law in 2010, and islet transplantation from BDDs was started in 2013. The present study assessed the influence of using pancreases from BDDs on islet transplantation in Japan. Methods: The donor information registered with the secretariat of islet transplants from 2012 was reviewed, and the results of 86 clinical islet isolations performed in Japan between 2003 and 2018 with non-heart-beating donors (NHBDs) (n = 71) and BDDs (n = 15) were investigated. Results: The number of cases for which donor information was registered with the secretariat of islet transplants increased to 1.84 cases/month from 2013 to 2018 in comparison to 1.44/month in 2012, when only NHBDs were used. The median pancreatic islet yield was 275,550 IEQ (Islet equivalents) in the NHBD group but 3,627,000 in the BDD group, which amounted to a statistically significant difference (p = 0.02). As a result, 38/71 cases (53.5%) were achieved successful islet isolation (>5000 IEQ per recipient weight (kg)) was achieved in 38/71 cases (53.5%) in the NHBD group, and 12/15 cases (80.0%) in the BDD group; thus, the rate of successful islet transplantation was higher in the BDD group. Conclusion: The use of pancreases from BDDs has increased the overall number of cases for which donor information is registered with the secretariat of islet transplants and has improved the performance of islet isolation, thereby increasing the probability of successfully achieving islet transplantation.

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