Diffusion into human islets is limited to molecules below 10kDa

Williams, S. Janette; Schwasinger-Schmidt, Tiffany; Zamierowski, David S.; Stehno‐Bittel, Lisa

doi:10.1016/j.tice.2012.05.001

Cited by 13 publications

(20 citation statements)

References 31 publications

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“…Previously, Williams et al reported that rat islets treated with papain became frangible and did not improve the outcome of islet transplantation in a syngenic model. 36,37 Thus, their report supports our results. It is presumed that such a fragmented islet structure may accumulate damage over time and eventually affect islet viability and functions negatively in vivo, which would not support long-term engraftment.…”

Section: Discussionsupporting

confidence: 90%

“…Spleen cells obtained from naive BALB/c mice were pretreated with 25 mg/mL mitomycin C (Sigma-Aldrich Co. M4287) at 37 C for 1 h. Then, BALB/c spleen cells were treated with 0, 1, or 10 mg/mL papain at 37 C for 15 min and used as stimulator cells. The responder cells (C57BL/6J, 1£10 5 cells) were cultured in the presence of stimulator cells (BALB/c, 1£10 5 cells) in RPMI 1640 (Thermo Fisher Scientific 22400-089) supplemented with 10% fetal bovine serum, 55 mM 2-mercaptoethanol (Thermo Fisher Scientific 21985-023) and 100 U/mL penicillin, and 100 mg/mL streptomycin (Thermo Fisher Scientific 15140-122) in 96-well V-bottomed plates (total volume: 200 ml at 37 C in a humidified atmosphere with 5% CO 2 ) and collected after 24, 48, 72 or 96 h of incubation.…”

Section: Mlrmentioning

confidence: 99%

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Pretreatment of donor islets with papain improves allograft survival without systemic immunosuppression in mice

Kumano

Nishinakamura

Mera

et al. 2016

Islets

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Although current immunosuppression protocols improve the efficacy of clinical allogenic islet transplantation, T cell-mediated allorejection remains unresolved, and major histocompatibility complexes (MHCs) play a crucial role in this process. Papain, a cysteine protease, has the unique ability to cleave the extracellular domain of the MHC class I structure. We hypothesized that pretreatment of donor islets with papain would diminish the expression of MHC class I on islets, reducing allograft immunogenicity and contributing to prolongation of islet allograft survival. BALB/ c islets pretreated with papain were transplanted into C57BL/6J mice as an acute allorejection model. Treatment with 1 mg/mL papain significantly prolonged islet allograft survival. In vitro, to determine the inhibitory effect on T cell-mediated alloreactions, we performed lymphocyte proliferation assays and mixed lymphocyte reactions. Host T cell activation against allogenic islet cells was remarkably suppressed by pretreatment of donor islet cells with 10 mg/mL papain. Flow cytometric analysis was also performed to investigate the effect of papain treatment on the expression of MHC class I on islets. One or 10 mg/mL papain treatment reduced MHC class I expression on the islet cell surface. Pretreatment of donor islets with papain suppresses MHC class Imediated allograft rejection in mice and contributes to prolongation of islet allograft survival without administration of systemic immunosuppressants. These results suggest that pretreatment of human donor islets with papain may reduce the immunogenicity of the donor islets and minimize the dosage of systemic immunosuppressants required in a clinical setting.

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Section: Discussionsupporting

confidence: 90%

Section: Mlrmentioning

confidence: 99%

Pretreatment of donor islets with papain improves allograft survival without systemic immunosuppression in mice

Kumano

Nishinakamura

Mera

et al. 2016

Islets

View full text Add to dashboard Cite

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“…In contrast, islets exposed to KU-32 showed less cell death (Figure 1(b), right). Islets maintained in culture have an increasing percentage of cell death, as we and others have shown [16, 17, 19, 20]. Exposure to KU-32 halted the time-dependent increase in cell death.…”

Section: Resultssupporting

confidence: 57%

“…Isolated islets are extremely fragile in vitro due to cell death from both apoptosis and necrosis [16, 17]. If KU-32 were to be used as a clinical intervention for patients with diabetic peripheral neuropathy, any possible cytotoxicity to islets must be avoided.…”

Section: Resultsmentioning

confidence: 99%

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KU-32, a Novel Drug for Diabetic Neuropathy, Is Safe for Human Islets and ImprovesIn VitroInsulin Secretion and Viability

Farmer

Williams

Novikova

et al. 2012

Experimental Diabetes Research

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KU-32 is a novel, novobiocin-based Hsp90 inhibitor that protects against neuronal glucotoxicity and reverses multiple clinical indices of diabetic peripheral neuropathy in a rodent model. However, any drug with potential for treating diabetic complications must also have no adverse effects on the function of pancreatic islets. Thus, the goal of the current study was to assess the effect of KU-32 on the in vitro viability and function of human islets. Treating human islets with KU-32 for 24 hours showed no toxicity as assessed using the alamarBlue assay. Confocal microscopy confirmed that with a minimum of 2-day exposure, KU-32 improved cellular viability by blocking apoptosis. Functionally, isolated human islets released more glucose-stimulated insulin when preincubated in KU-32. However, diabetic BKS-db/db mice, a model for type 2 diabetes, administered KU-32 for 10 weeks did not show any significant changes in blood glucose and insulin levels, despite having greater insulin staining/beta cell in the pancreas compared to untreated BKS db/db mice. In summary, KU-32 did not harm isolated human islets and may even be protective. However, the effect does not appear significant enough to alter the in vivo metabolic parameters of diabetic mice.

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Fabrication of functional rat pseudo‐islets after cryopreservation of pancreatic islets or dispersed islet cells

Nakayama-Iwatsuki

Hirabayashi

Hochi

2021

J Tissue Eng Regen Med

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Dispersed single cells from pancreatic islets can configure the three‐dimensional islet‐like architecture (pseudo‐islets) with insulin secretion potential and controllable size through their aggregation property. The present study was designed to investigate whether cryopreservation of islets or islet cells can contribute to the efficient pseudo‐islet fabrication in the rat model. In control group (CT), islet single cells were prepared by trypsin digestion of 50–400‐µm ø fresh control islets, and then cultured for 3 days in the U‐bottom microwell to fabricate pseudo‐islets. In vitrification‐warming group (VW), islet single cells were prepared from postwarm islets cryopreserved by vitrification on nylon mesh device, and then cultured for 3 days. In freezing group (FR), islet single cells originated from fresh islets were subjected to a conventional Bicell® freezing, and postthaw cells were cultured for 3 days. To generate 1 islet equivalent pseudo‐islets (150 µm ø) by the sphere culture, 1250 CT cells, 1250 VW cells, and 1500 FR cells were seeded to each microwell. The viability of the pseudo‐islets was comparable among the three groups (93.9%–96.9%). Furthermore, the insulin secretion assay showed that those pseudo‐islets responded sufficiently to the high glucose stimulation. Immunostaining for insulin and glucagon showed that the endocrine cell arrangement of those pseudo‐islets is similar to that of native and isolated islets. These islets/pseudo‐islets had the β‐cells in core and the α‐cells in mantle, which was typical characteristic of the rodent islets. However, some clusters of α‐cells were observed inside the FR pseudo‐islets. Interestingly, the VW pseudo‐islets had significantly fewer α‐cells than the CT or FR pseudo‐islets. These results suggest that the sphere culture of islet cells is useful tool to generate the pseudo‐islets with the customized size and normal functionality, even after islet cryopreservation.

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Diffusion into human islets is limited to molecules below 10kDa

Cited by 13 publications

References 31 publications

Pretreatment of donor islets with papain improves allograft survival without systemic immunosuppression in mice

Pretreatment of donor islets with papain improves allograft survival without systemic immunosuppression in mice

KU-32, a Novel Drug for Diabetic Neuropathy, Is Safe for Human Islets and ImprovesIn VitroInsulin Secretion and Viability

Fabrication of functional rat pseudo‐islets after cryopreservation of pancreatic islets or dispersed islet cells

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