Characterization of Islet Preparations

Colton, Clark K.; Papas, Klearchos K.; Pisania, Anna; Rappel, Michael J.; Powers, Daryl E.; O’Neil, John J.; Omer, Abdulkadir; Weir, Gordon C.; Bonner-Weir, Susan

doi:10.1016/b978-012369415-7/50007-7

Cited by 32 publications

(60 citation statements)

References 141 publications

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“…Last, combination of nuclei counts and DNA measurements provided insight into the extent of recent cell damage. OCR, a direct measure of the rate of oxidative phosporylation in aerobic cells, has been suggested as a better measure of mitochondrial function than nucleotide concentrations 8,9 and has been measured with various systems. [34][35][36] We developed a stirred microchamber that permits rapid, accurate OCR measurements with a small volume of islet tissue.…”

Section: Introductionmentioning

confidence: 99%

“…15,16 Examination of viability by assessment of membrane integrity with vital stains such as fluorescein diacetate/propidium iodide does not reflect true viability because it may not account for cells undergoing early cell death processes, during which cells have not yet developed damage to their cell membrane. 8,9,17,18 Measures of cellular energetic state, including ATP content [19][20][21][22][23][24] and ATP/ADP and related ratios, [25][26][27] have been investigated with modest success. ATP content varies enormously between islets from different species, between human islet preparations, [20][21][22] with time in culture, 20,21 and with donor age.…”

Section: Introductionmentioning

confidence: 99%

“…This requirement has not been achieved, in part because the characteristics determined by currently accepted assay methods, individually or collectively, do not correlate with transplantation outcome. [2][3][4][5][6][7][8][9] Development of meaningful assays of islet properties is challenging for several reasons 8 : (1) Many techniques suitable for cells are not practical with islets because of their three-dimensional aggregate structure. Islets cannot be usefully dissociated into dispersed cells by agitation and incubation with serine proteases such as trypsin because from 30% to 50% of the cells are lost during dissociation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

Johnson

O'Sullivan

D'Aoust

et al. 2011

Tissue Engineering Part C: Methods

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

Johnson

O'Sullivan

D'Aoust

et al. 2011

Tissue Engineering Part C: Methods

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“…Islet dose was calculated using standard methods [7,25]. Briefly, islets >50μm in diameter were enumerated by manual count with an inverted light microscope and classified into size ranges in increments of 50 μm.…”

Section: Methodsmentioning

confidence: 99%

“…Prior to transplant, islet preparations are evaluated by several product release criteria assessments in order to ensure that recipients are receiving products that have a high potential of reversing diabetes and to satisfy federal regulation requirements. These assays commonly include islet dose based on the number of islet equivalents (IE) transplanted normalized to recipient body weight (IE/kg), fractional viability as measured by fluorescence-based membrane integrity stains, and glucose stimulated insulin release (GSIR) [7,8]. …”

Section: Introductionmentioning

confidence: 99%

Islet Oxygen Consumption Rate Dose Predicts Insulin Independence for First Clinical Islet Allotransplants

Kitzmann

O’Gorman

Kin

et al. 2014

Transplantation Proceedings

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Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx.

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A stirred microchamber for oxygen consumption rate measurements with pancreatic islets

Papas

Pisania

et al. 2007

Biotech & Bioengineering

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106

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Improvements in pancreatic islet transplantation for treatment of diabetes are hindered by the absence of meaningful islet quality assessment methods. Oxygen consumption rate (OCR) has previously been used to assess the quality of organs and primary tissue for transplantation. In this study, we describe and characterize a stirred microchamber for measuring OCR with small quantities of islets. The device has a titanium body with a chamber volume of about 200 µL and is magnetically stirred and water jacketed for temperature control. Oxygen partial pressure (pO 2 ) is measured by fluorescence quenching with a fiber optic probe, and OCR is determined from the linear decrease of pO 2 with time. We demonstrate that measurements can be made rapidly and with high precision. Measurements with βTC3 cells and islets show that OCR is directly proportional to the number of viable cells in mixtures of live and dead cells and correlate linearly with membrane integrity measurements made with cells that have been cultured for 24 h under various stressful conditions.

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Characterization of Islet Preparations

Cited by 32 publications

References 141 publications

Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

Quantitative Assessment of Islets of Langerhans Encapsulated in Alginate

Islet Oxygen Consumption Rate Dose Predicts Insulin Independence for First Clinical Islet Allotransplants

A stirred microchamber for oxygen consumption rate measurements with pancreatic islets

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