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| 2. |
- Correa-Medina, Mayrin, et al.
(author)
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MicroRNA miR-7 is preferentially expressed in endocrine cells of the developing and adult human pancreas.
- 2009
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In: Gene Expression Patterns. - : Elsevier BV. - 1567-133X .- 1872-7298. ; 9:4, s. 193-9
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Journal article (peer-reviewed)abstract
- MicroRNAs (miRNA) are small non-coding RNAs that inhibit gene expression through binding to complementary messenger RNA sequences. miRNAs have been predicted to target genes important for pancreas development, proper endocrine cell function and metabolism. We previously described that miRNA-7 (miR-7) was the most abundant and differentially expressed islet miRNA, with 200-fold higher expression in mature human islets than in acinar tissue. Here we have analyzed the temporal and spatial expression of miR-7 in human fetal pancreas from 8 to 22 weeks of gestational age (wga). Human fetal (8-22wga) and adult pancreases were processed for immunohistochemistry, in situ hybridization, and quantitative RT-PCR of miRNA and mRNA. miR-7 was expressed in the human developing pancreas from around 9wga and reached its maximum expression levels between 14 and 18wga, coinciding with the exponential increase of the pancreatic endocrine hormones. Throughout development miR-7 expression was preferentially localized to endocrine cells and its expression persisted in the adult pancreas. The present study provides a detailed analysis of the spatiotemporal expression of miR-7 in developing human pancreas. The specific localization of miR-7 expression to fetal and adult endocrine cells indicates a potential role for miR-7 in endocrine cell differentiation and/or function. Future functional studies of a potential role for miR-7 function in islet cell differentiation and physiology are likely to identify novel targets for the treatment of diabetes and will lead to the development of improved protocols for generating insulin-producing cells for cell replacement therapy.
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| 4. |
- Friberg, Andrew S., et al.
(author)
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Quantification of the Islet Product : Presentation of a Standardized Current Good Manufacturing Practices Compliant System With Minimal Variability
- 2011
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In: Transplantation. - 0041-1337 .- 1534-6080. ; 91:6, s. 677-683
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Journal article (peer-reviewed)abstract
- Background. Accurate islet quantification has proven difficult to standardize in a good manufacturing practices (GMP) approved manner. Methods. The influence of assessment variables from both manual and computer-assisted digital image analysis (DIA) methods were compared using calibrated, standardized microspheres or islets alone. Additionally, a mixture of microspheres and exocrine tissue was used to evaluate the variability of both the current, internationally recognized, manual method and a novel GMP-friendly purity-and volume-based method (PV) evaluated by DIA in a semiclosed, culture bag system. Results. Computer-assisted DIA recorded known microsphere size distribution and quantities accurately. By using DIA to evaluate islets, the interindividual manually evaluated percent coefficients of variation (CV%; n = 14) were reduced by almost half for both islet equivalents (IEs; 31% vs. 17%, P = 0.002) and purity (20% vs. 13%, P = 0.033). The microsphere pool mixed with exocrine tissue did not differ from expected IE with either method. However, manual IE resulted in a total CV% of 44.3% and a range spanning 258 kIE, whereas PV resulted in CV% of 10.7% and range of 60 k IE. Purity CV% for each method were similar approximating 10.5% and differed from expected by +7% for the manual method and +3% for PV. Conclusion. The variability of standard counting methods for islet samples and clinical quantities of microspheres mixed with exocrine tissue were reduced with DIA. They were reduced even further by use of a semiclosed bag system compared with standard manual counting, thereby facilitating the standardization of islet evaluation according to GMP standards.
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| 5. |
- Hering, Bernhard J., et al.
(author)
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Phase 3 Trial of Transplantation of Human Islets in Type 1 Diabetes Complicated by Severe Hypoglycemia
- 2016
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In: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 39:7, s. 1230-1240
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Journal article (peer-reviewed)abstract
- OBJECTIVE Impaired awareness of hypoglycemia (IAH) and severe hypoglycemic events (SHEs) cause substantial morbidity and mortality in patients with type 1 diabetes (T1D). Current therapies are effective in preventing SHEs in 50-80% of patients with IAH and SHEs, leaving a substantial number of patients at risk. We evaluated the effectiveness and safety of a standardized human pancreatic islet product in subjects in whom IAH and SHEs persisted despite medical treatment. RESEARCH DESIGN AND METHODS This multicenter, single-arm, phase 3 study of the investigational product purified human pancreatic islets (PHPI) was conducted at eight centers in North America. Forty-eight adults with T1D for >5 years, absent stimulated C-peptide, and documented IAH and SHEs despite expert care were enrolled. Each received immunosuppression and one or more transplants of PHPI, manufactured on-site under good manufacturing practice conditions using a common batch record and standardized lot release criteria and test methods. The primary end point was the achievement of HbA(1c) <7.0% (53 mmol/mol) at day 365 and freedom from SHEs from day 28 to day 365 after the first transplant. RESULTS The primary end point was successfully met by 87.5% of subjects at 1 year and by 71% at 2 years. The median HbA(1c) level was 5.6% (38 mmol/mol) at both 1 and 2 years. Hypoglycemia awareness was restored, with highly significant improvements in Clarke and HYPO scores (P > 0.0001). No study-related deaths or disabilities occurred. Five of the enrollees (10.4%) experienced bleeds requiring transfusions (corresponding to 5 of 75 procedures), and two enrollees (4.1%) had infections attributed to immunosuppression. Glomerular filtration rate decreased significantly on immunosuppression, and donor-specific antibodies developed in two patients. CONCLUSIONS Transplanted PHPI provided glycemic control, restoration of hypoglycemia awareness, and protection from SHEs in subjects with intractable IAH and SHEs. Safety events occurred related to the infusion procedure and immunosuppression, including bleeding and decreased renal function. Islet transplantation should be considered for patients with T1D and IAH in whom other, less invasive current treatments have been ineffective in preventing SHEs.
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| 6. |
- Jeon, Jongmin, et al.
(author)
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Endocrine cell clustering during human pancreas development
- 2009
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In: Journal of Histochemistry and Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 57:9, s. 811-824
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Journal article (peer-reviewed)abstract
- The development of efficient, reproducible protocols for directed in vitro differentiation of hES cells into insulin producing beta cells will benefit greatly from increased knowledge regarding the spatiotemporal expression profile of key instructive factors involved in human endocrine cell generation. Human fetal pancreases, from 7 to 21 weeks of gestational age, were collected following consent immediately after pregnancy termination and processed for immunostaining, in situ hybridization and real-time RT-PCR expression analyses. Islet-like structures appear from approximately week 12 and unlike the mixed architecture observed in the adult islets, fetal islets are initially formed predominantly by aggregated insulin or glucagon-expressing cells. The period studied (7-22 weeks) coincides with a decrease in the proliferation and an increase in the differentiation of the progenitor cells, the initiation of NGN3 expression and the appearance of differentiated endocrine cells. The present study provides a detailed characterization of islet formation and expression profiles of key intrinsic and extrinsic factors during human pancreas development. This information is beneficial for the development of efficient protocols that will allow guided in vitro differentiation of hES cells into insulin-producing cells.
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| 8. |
- Markmann, James F., et al.
(author)
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Executive Summary of IPITA-TTS Opinion Leaders Report on the Future of beta-Cell Replacement
- 2016
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In: Transplantation. - 0041-1337 .- 1534-6080. ; 100:7, s. E25-E31
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Research review (peer-reviewed)abstract
- The International Pancreas and Islet Transplant Association (IPITA), in conjunction with the Transplantation Society (TTS), convened a workshop to consider the future of pancreas and islet transplantation in the context of potential competing technologies that are under development, including the artificial pancreas, transplantation tolerance, xenotransplantation, encapsulation, stem cell derived beta cells, beta cell proliferation, and endogenous regeneration. Separate workgroups for each topic and then the collective group reviewed the state of the art, hurdles to application, and proposed research agenda for each therapy that would allow widespread application. Herein we present the executive summary of this workshop that focuses on obstacles to application and the research agenda to overcome them; the full length article with detailed background for each topic is published as an online supplement to Transplantation.
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| 9. |
- Markmann, James F., et al.
(author)
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Phase 3 trial of human islet-after-kidney transplantation in type 1 diabetes
- 2021
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In: American Journal of Transplantation. - : John Wiley & Sons. - 1600-6135 .- 1600-6143. ; 21:4, s. 1477-1492
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Journal article (peer-reviewed)abstract
- Allogeneic islet transplant offers a minimally invasive option for beta cell replacement in the treatment of type 1 diabetes (T1D). The CIT consortium trial of purified human pancreatic islets (PHPI) in patients with T1D after kidney transplant (CIT06), a National Institutes of Health-sponsored phase 3, prospective, open-label, single-arm pivotal trial of PHPI, was conducted in 24 patients with impaired awareness of hypoglycemia while receiving intensive insulin therapy. PHPI were manufactured using standardized processes. PHPI transplantation was effective with 62.5% of patients achieving the primary endpoint of freedom from severe hypoglycemic events and HbA(1c) <= 6.5% or reduced by >= 1 percentage point at 1 year posttransplant. Median HbA(1c)declined from 8.1% before to 6.0% at 1 year and 6.3% at 2 and 3 years following transplant (P < .001 for all vs baseline), with related improvements in hypoglycemia awareness and glucose variability. The improved metabolic control was associated with better health-related and diabetes-related quality of life. The procedure was safe and kidney allograft function remained stable after 3 years. These results add to evidence establishing allogeneic islet transplant as a safe and effective treatment for patients with T1D and unstable glucose control despite intensive insulin treatment, supporting the indication for PHPI in the post-renal transplant setting.
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| 10. |
- Oström, Maria, et al.
(author)
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Retinoic acid promotes the generation of pancreatic endocrine progenitor cells and their further differentiation into beta-cells
- 2008
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:7, s. e2841-
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Journal article (peer-reviewed)abstract
- The identification of secreted factors that can selectively stimulate the generation of insulin producing beta-cells from stem and/or progenitor cells represent a significant step in the development of stem cell-based beta-cell replacement therapy. By elucidating the molecular mechanisms that regulate the generation of beta-cells during normal pancreatic development such putative factors may be identified. In the mouse, beta-cells increase markedly in numbers from embryonic day (e) 14.5 and onwards, but the extra-cellular signal(s) that promotes the selective generation of beta-cells at these stages remains to be identified. Here we show that the retinoic acid (RA) synthesizing enzyme Raldh1 is expressed in developing mouse and human pancreas at stages when beta-cells are generated. We also provide evidence that RA induces the generation of Ngn3(+) endocrine progenitor cells and stimulates their further differentiation into beta-cells by activating a program of cell differentiation that recapitulates the normal temporal program of beta-cell differentiation.
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| 11. |
- Pugliese, Alberto, et al.
(author)
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Sequence analysis of the diabetes-protective human leukocyte antigen-DQB1*0602 allele in unaffected, islet cell antibody-positive first degree relatives and in rare patients with type 1 diabetes
- 1999
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In: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 84:5, s. 1722-1728
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Journal article (peer-reviewed)abstract
- The human leukocyte antigen (HLA)-DQA1*0102/DQB1*0602/DRB1*1501 (DR2) haplotype confers strong protection from type 1 diabetes. Growing evidence suggests that such protection may be mostly encoded by the DQB1*0602 allele, and we reported that even first degree relatives with islet cell antibodies (ICA) have an extremely low diabetes risk if they carry DQB1*0602. Recently, novel variants of the DQB1*0602 and *0603 alleles were reported in four patients with type 1 diabetes originally typed as DQB1*0602 with conventional techniques. One inference from this observation is that DQB1*0602 may confer absolute protection and may never occur in type 1 diabetes. By this hypothesis, all patients typed as DQB1*0602 positive with conventional techniques should carry one of the above diabetes-permissive variants instead of the protective DQB1*0602. Such variants could also occur in ICA/DQB1*0602-positive relatives, with the implication that their diabetes risk could be significantly higher than previously estimated. We therefore sequenced the DQB1*0602 and DQA1*0102 alleles in all ICA/DQB1*0602-positive relatives (n = 8) previously described and in six rare patients with type 1 diabetes and DQB1*0602. We found that all relatives and patients carry the known DQB1*0602 and DQA1*0102 sequences, and none of them has the mtDNA A3243G mutation associated with late-onset diabetes in ICA-positive individuals. These findings suggest that diabetes-permissive DQB1*0602/3 variants may be very rare. Thus, although the protective effect associated with DQB1*0602 is extremely powerful, it is not absolute. Nonetheless, the development of diabetes in individuals with DQB1*0602 remains extremely unlikely, even in the presence of ICA, as confirmed by our further evaluation of ICA/DQB1*0602-positive relatives, none of whom has yet developed diabetes.
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| 13. |
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| 14. |
- Ricordi, Camillo, et al.
(author)
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National Institutes of Health-Sponsored Clinical Islet Transplantation Consortium Phase 3 Trial : Manufacture of a Complex Cellular Product at Eight Processing Facilities
- 2016
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In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 65:11, s. 3418-3428
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Journal article (peer-reviewed)abstract
- Eight manufacturing facilities participating in the National Institutes of Health-sponsored Clinical Islet Transplantation (CIT) Consortium jointly developed and implemented a harmonized process for the manufacture of allogeneic purified human pancreatic islet (PHPI) product evaluated in a phase 3 trial in subjects with type 1 diabetes. Manufacturing was controlled by a common master production batch record, standard operating procedures that included acceptance criteria for deceased donor organ pancreata and critical raw materials, PHPI product specifications, certificate of analysis, and test methods. The process was compliant with Current Good Manufacturing Practices and Current Good Tissue Practices. This report describes the manufacturing process for 75 PHPI clinical lots and summarizes the results, including lot release. The results demonstrate the feasibility of implementing a harmonized process at multiple facilities for the manufacture of a complex cellular product. The quality systems and regulatory and operational strategies developed by the CIT Consortium yielded product lots that met the prespecified characteristics of safety, purity, potency, and identity and were successfully transplanted into 48 subjects. No adverse events attributable to the product and no cases of primary nonfunction were observed.
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