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Articles by Jose Oberholzer in JoVE
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Multi-Параметрический Островок Perifusion системы в микрожидкостных устройств Perifusion
Adeola F. Adewola1, Yong Wang1, Tricia Harvat1, David T. Eddington2, Dongyoung Lee1, Jose Oberholzer1,2
1Department of Surgery, University of Illinois, Chicago, 2Department of Bioengineering, University of Illinois, Chicago
Микрожидкостных устройств perifusion островок был разработан для оценки динамических секреции инсулина несколько островков и одновременное флуоресценции притока кальция и митохондриальной возможных изменений.
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Количественный и временной контроль кислорода микроокружения в Единой Иле уровня
Joe Fu-Jiou Lo1, Yong Wang2,3, Zidong Li1, Zhengtuo Zhao1, Di Hu1, David T. Eddington3, Jose Oberholzer2,3
1Department of Mechanical Engineering, University of Michigan-Dearborn, 2Department of Surgery/Transplant, University of Illinois at Chicago, 3Department of Bioengineering, University of Illinois at Chicago
Микрофлюидных контроль кислорода дает больше, чем просто удобство и скорость в течение гипоксии камер для биологических экспериментов. Особенно, когда осуществляется путем диффузии через мембрану, Микрожидкостных кислород может обеспечить одновременное жидкости и газовой фазы модуляции на микроуровне уровне. Этот метод позволяет динамические мульти-параметрические эксперименты важны для изучения островок патофизиологии.
Other articles by Jose Oberholzer on PubMed
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Molecular Detection of Circulating Beta-cells After Islet Transplantation
Diabetes.
Mar, 2002 |
Pubmed ID: 11872650 Islet transplantation is a promising treatment for type 1 diabetes. However, islet grafts are submitted to multiple injuries, including immunosuppressive drug toxicity, hyperglycemia, hypoxia, unspecific inflammatory reactions, as well as allo- and autoimmune destruction. Therapeutic approaches to these damage mechanisms require early detection of islet injury, which is currently not feasible because of the lack of efficient markers. Based on the hypothesis of islet dissociation and release of islet cells into the circulation during islet injury, we designed a highly sensitive and specific molecular assay, able to detect two beta-cells per milliliter of venous blood by RT-PCR of insulin mRNA. We report that circulating beta-cells can be demonstrated up to 10 weeks after intraportal islet transplantation, as assessed after six islet grafts in four type 1 diabetic patients. Furthermore, our results suggest that the time during which circulating islet cells can be detected may depend on the graft environment and the immunosuppressive regimen. This test may allow better estimation of islet cell loss and identification of factors involved in islet graft injury.
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Glucose-induced Beta Cell Production of IL-1beta Contributes to Glucotoxicity in Human Pancreatic Islets
The Journal of Clinical Investigation.
Sep, 2002 |
Pubmed ID: 12235117 In type 2 diabetes, chronic hyperglycemia is suggested to be detrimental to pancreatic beta cells, causing impaired insulin secretion. IL-1beta is a proinflammatory cytokine acting during the autoimmune process of type 1 diabetes. IL-1beta inhibits beta cell function and promotes Fas-triggered apoptosis in part by activating the transcription factor NF-kappaB. Recently, we have shown that increased glucose concentrations also induce Fas expression and beta cell apoptosis in human islets. The aim of the present study was to test the hypothesis that IL-1beta may mediate the deleterious effects of high glucose on human beta cells. In vitro exposure of islets from nondiabetic organ donors to high glucose levels resulted in increased production and release of IL-1beta, followed by NF-kappaB activation, Fas upregulation, DNA fragmentation, and impaired beta cell function. The IL-1 receptor antagonist protected cultured human islets from these deleterious effects. beta cells themselves were identified as the islet cellular source of glucose-induced IL-1beta. In vivo, IL-1beta-producing beta cells were observed in pancreatic sections of type 2 diabetic patients but not in nondiabetic control subjects. Similarly, IL-1beta was induced in beta cells of the gerbil Psammomys obesus during development of diabetes. Treatment of the animals with phlorizin normalized plasma glucose and prevented beta cell expression of IL-1beta. These findings implicate an inflammatory process in the pathogenesis of glucotoxicity in type 2 diabetes and identify the IL-1beta/NF-kappaB pathway as a target to preserve beta cell mass and function in this condition.
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Monounsaturated Fatty Acids Prevent the Deleterious Effects of Palmitate and High Glucose on Human Pancreatic Beta-cell Turnover and Function
Diabetes.
Mar, 2003 |
Pubmed ID: 12606514 Glucotoxicity and lipotoxicity contribute to the impaired beta-cell function observed in type 2 diabetes. Here we examine the effect of saturated and monounsaturated fatty acids at different glucose concentrations on human beta-cell turnover and secretory function. Exposure of cultured human islets to saturated fatty acid and/or to an elevated glucose concentration for 4 days increased beta-cell DNA fragmentation and decreased beta-cell proliferation. In contrast, the monounsaturated palmitoleic acid or oleic acid did not affect DNA fragmentation and induced beta-cell proliferation. Moreover, each monounsaturated fatty acid prevented the deleterious effects of both palmitic acid and high glucose concentration. The cell-permeable ceramide analogue C(2)-ceramide mimicked both the palmitic acid-induced beta-cell apoptosis and decrease in proliferation. Furthermore, the ceramide synthetase inhibitor fumonisin B1 blocked the deleterious effects of palmitic acid on beta-cell turnover. In addition, palmitic acid decreased Bcl-2 expression and induced release of cytochrome c from the mitochondria into the cytosol, which was prevented by fumonisin B1 and by oleic acid. Finally, each monounsaturated fatty acid improved beta-cell secretory function that was reduced by palmitic acid and by high glucose. Thus, in human islets, the saturated palmitic acid and elevated glucose concentration induce beta-cell apoptosis, decrease beta-cell proliferation, and impair beta-cell function, which can be prevented by monounsaturated fatty acids. The deleterious effect of palmitic acid is mediated via formation of ceramide and activation of the apoptotic mitochondrial pathway, whereas Bcl-2 may contribute to the protective effect of monounsaturated fatty acids.
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Islet Autotransplantation After Left Pancreatectomy for Non-enucleable Insulinoma
American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons.
Oct, 2003 |
Pubmed ID: 14510705 Insulinoma is a rare, almost always benign endocrine tumor of the pancreas, clinically characterized by hyperinsulinemic, hypoglycemic episodes. Surgical excision is the therapy of choice, which may lead to postpancreatectomy diabetes mellitus in the case of extensive pancreatic resection. We present the cases and the metabolic follow up of two patients, 81 and 73 years old, with insulinoma localized close to the main duct in the pancreatic neck. Both patients underwent an 80% left pancreatectomy, avoiding a pancreatico-enteric anastomosis. In order to prevent postpancreatectomy diabetes, the islets from the tumor-free part of the resected pancreas were isolated and injected via a right colic vein into the portal system. After a follow up of 6 and 3 years respectively, both patients remained insulin-independent without any dietary restrictions. Fasting and glucagon-stimulated C-peptide-levels and glycosylated hemoglobin remained within normal range. There were no signs of recurrent insulinoma. Liver biopsy performed in one patient at 1 year after autotransplantation, showed intact, insulin-producing islets within the portal spaces. In conclusion, autologous islet transplantation can preserve the insulin secretory reserve after extended left pancreatectomy for the treatment of benign tumors in the pancreatic neck.
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Activation of Human Macrophages by Allogeneic Islets Preparations: Inhibition by AOP-RANTES and Heparinoids
Immunology.
Apr, 2004 |
Pubmed ID: 15056378 During transplantation, pancreatic islets release chemokines which promote macrophage attraction, hampering engraftment of islets. The aim of this study was to modulate chemotaxis and the immune response of human macrophages induced by islets. Human monocyte-derived macrophages of healthy subjects were exposed to supernatants of human islets. Chemotaxis, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) release were evaluated. To modulate migration, human macrophages were incubated in the presence of aminooxypentane-regulated on activation, normal, T-cell expressed, and secreted (AOP-RANTES), a potent antagonist of CCR5. Chemotactic activity of islets supernatant was modulated by the addition of heparin or heparinoids [pentosan and calix[8S]arene (C8S)]. AOP-RANTES significantly reduced, in a dose-dependent manner, macrophage chemotaxis and cytokine release induced by islets supernatant. The chemotactic index was reduced from 3.05 +/- 0.27 to 0.71 +/- 12, TNF-alpha from 1205 +/- 52 to 202 +/- 12 pg/ml, and IL-1beta from 234 +/- 12 to 10 +/- 6 pg/ml. The trapping of chemokines by heparinoids reduced the chemotactic activity of islets supernatant from 3.05 +/- 0.27 to 1.2 +/- 0.1 with heparin or pentosan and to 1.72 +/- 0.22 with C8S, and also decreased the TNF-alpha release by human macrophages from 1205 +/- 35 to 1000 +/- 26 (C8S), 250 +/- 21 (heparin) and 320 +/- 19 (pentosan) pg/ml, and IL-1beta from 234 +/- 13 to 151 +/- 5 (C8S), 50 +/- 3 (heparin) and 57 +/- 4 (pentosan) pg/ml. In conclusion, AOP-RANTES and heparinoids inhibit human macrophage activation and migration induced by islets supernatant.
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Sirolimus-based Immunosuppression for Liver Transplantation in the Presence of Extended Criteria for Hepatocellular Carcinoma
Liver Transplantation : Official Publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society.
Oct, 2004 |
Pubmed ID: 15376305 An increasing number of patients with hepatocellular carcinoma (HCC) are undergoing evaluation for listing for liver transplantation. Criteria for selection require ongoing review for suitability. A consecutive series of 40 patients with HCC within the standard Milan criteria (single tumors n = 19 < 5 cm, or up to 3 tumors < 3 cm) and beyond (Extended Criteria; single tumors n = 21 < 7.5 cm, multiple tumors < 5 cm) underwent liver transplant with a sirolimus-based immunosuppressive protocol designed to minimize exposure to calcineurin inhibitors and steroids. At 44.3 +/- 19.3 months (mean +/- standard deviation) follow-up, 1- and 4-year survivals (Kaplan-Meier) are 94.1 +/- 5.7% and 87.4 +/- 9.3%, in the Milan group, respectively, and 90.5 +/- 6.4% and 82.9 +/- 9.3% in the Extended Criteria group, respectively. Five patients died during follow-up, only 1 from recurrent HCC. Five tumor recurrences have occurred at median 17 (mean 22 +/- 17) months posttransplant, 1 in the Milan group and 4 in the Extended Criteria group. Median survival in the patients with recurrent tumor is 42 months (mean 45 +/- 25), and the median postrecurrence survival is 15.5 months (mean 23 +/- 16). The rate of patients who were alive and free of tumor at 1 and 4 years is 94.1 +/- 5.7% and 81.1 +/- 9.9%, respectively, in the Milan group and is 90.5 +/- 6.4% and 76.8 +/- 10.5%, respectively, in the Extended Criteria group. Five patients had sirolimus discontinued for toxicity, while 24 of 35 surviving patients have sirolimus monotherapy immunosuppression. In conclusion, the Milan criteria for liver transplantation in the presence of HCC can be carefully extended without compromising outcomes. This sirolimus based immunosuppression protocol appears to have beneficial effects on tumor recurrence and survival with an acceptable rate of rejection and toxicity.
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Kidney Transplantation at the University of Illinois at Chicago from 1988-2004
Clinical Transplants.
2004 |
Pubmed ID: 16704147 The Division of Transplantation at the University of Illinois at Chicago (UIC) was established in 1968 by Dr. Olga M. Jonasson, who performed the first living related kidney transplant in Illinois. The UIC Hospital is a typical inner city hospital serving primarily minorities and under-privileged populations with significant challenge for issues such as compliance, insurance coverage, low income, and degree of education. We analyzed the outcomes of 67 pediatric and 801 adult consecutive renal allotransplantations performed at the University of Illinois at Chicago (UIC) from January 1988-December 2002 and more recent information in relation to newly developed programs (robotic living donation, transplantation in sensitized patients, early steroid discontinuation, ethnicity tailored immunosuppression) until November 2004 (21 pediatric and 172 adults). The one-year graft survival has improved comparing the cases performed between 1988-1998 versus cases after 1998 from 82-88%, with similar patient survival. However, the overall 5-year patient and graft survival has not changed significantly in the 2 different eras and is currently 85% and 65%, respectively. With the use of minimally invasive, robotic-assisted living donor nephrectomy, the use of living donors has increased and these now represent 75% of the kidney donors at UIC. Transplantation in highly sensitized recipients has become more successful with the use of plasmapheresis resulting in 100% patient and graft survival and a 10% acute rejection rate in the first series of 20 patients. Early steroid discontinuation (steroid discontinued at day 6 after transplantation) has allowed for significant improvement of results in pediatric recipients. We have 100% one-year patient and graft survival and no acute rejections in a series of 13 children, compared with a 25% rejection rate in 13 children with steroid-containing immunosuppession. Tailored immunosuppression with early steroid discontinuation now achieves equal early results in African American as in any other ethnic group with 98-99% patient and graft survival and acute rejection rates below 10%. Of interest will be the future evolution of long-term patient and graft survival under the new immunosuppressive protocols with early steroid discontinuation achieving very low acute rejection rates and impressive one-year survival rates. There is reason for optimism that the improved early results will translate into better long-term outcomes.
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Steroid Avoidance in Liver Transplantation
Canadian Journal of Gastroenterology = Journal Canadien De Gastroenterologie.
Oct, 2004 |
Pubmed ID: 16807621 Corticosteroids have always played a valuable role in transplantation. Unfortunately, they are subject to a wide range of side effects, such as hyperlipidemia, hypertension, diabetes mellitus, osteoporosis, growth retardation and Cushingoid appearance. Steroids may also exacerbate problems that existed before surgery, including malignancy, hepatitis B and hepatitis C. New, powerful immunosuppressants have allowed steroid use to be reduced or avoided altogether, but use of these regimens is not simple and may be associated with late acute rejection and recurrence of autoimmune disease. The present review examines the rationale for steroid avoidance in liver transplantation and assesses the new regimens that are currently being developed.
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Microbial Surveillance During Human Pancreatic Islet Isolation
Transplant International : Official Journal of the European Society for Organ Transplantation.
May, 2005 |
Pubmed ID: 15819808 The aim of the study was to investigate microbiological contamination rate during human pancreatic islet isolation. Between 1996 and 2002, pancreas preservation media and post-purification islet preparations were screened for microbiological contamination. After arrival in the laboratory, pancreata were washed prior to enzyme perfusion with either Hank's balanced salt solution (Group I, n = 170, 1996 to 2001) or decontaminated with polyvidonum-iodine, cefazoline, and amphotericine B (Group II, n = 45, 2001 to 2002). Microbiological contamination of preservation media was observed in 56% and 84% for Groups I and II, respectively. Analysis of contaminants revealed 74% Gram-positive, 21% Gram-negative bacteria and 5% fungi. Duration of transport had an influence on the rate of contamination (P < 0.05). After islet isolation, Group I presented microbial contamination of 16 islet preparations (9.4%) [i.e. Gram-positive bacteria (n = 10), Gram-negative bacteria (n = 4), and fungi (n = 2)]. In Group II, only 2 islet preparations (4.4%) presented microbial contamination. Microbial contamination during pancreas procurement occurs frequently. Most microorganisms are eliminated during islet isolation, and de novo contaminations during islet isolation are rare. Pancreas decontamination reduces the risk of infection of the final islet preparation.
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Effect of Microcapsule Composition and Short-term Immunosuppression on Intraportal Biocompatibility
Cell Transplantation.
2005 |
Pubmed ID: 15881425 With higher nutrient and oxygen supply and close contact to blood, the portal vein is a possible alternative to the peritoneal cavity for transplantation of encapsulated cells. Data regarding intraportal biocompatibility of microcapsules are lacking. Microcapsules were built from five alginate types differing in their molar mass and mannuronic/guluronic acid ratios by complex formation with divalent cations (barium or calcium) or mixtures of divalent cations and polycations. They were injected in the portal vein of rats, and cellular and fibrotic pericapsular infiltration thickness was measured 3 and 7 days after implantation. Overgrowth was characterized using various stainings or immunohistochemistry (hematoxylin and eosin, Giemsa, ED-1 for monocyte/macrophage, alpha-actin for myofibroblasts, CD31 for endothelial cells). The impact of short-term immunosuppression (gadolinium-chloride IV 20 mg/kg/day on days--1 and 4 as well as 10 days of rapamycin PO 1 mg/kg/day, tacrolimus PO 3 mg/kg/day, or combinations of rapamycin/tacrolimus or gadolinium/tacrolimus) was further assessed 3, 7, and 42 days after implantation. Overall, overgrowth increased from day 3 to day 7 (p < 0.05). Three and 7 days after implantation, polycation-containing microcapsules induced more reaction than microbeads (p < 0.0001 and p < 0.01). Considering polycation-free beads, barium-alginate induced the weakest reaction. Biocompatibility of microbeads was independent of mannuronic/guluronic acid ratio and molar mass of the alginate. Infiltration was mainly a monocyte/macrophage-rich foreign body reaction, but an eosinophil-containing immunoallergic reaction was also observed. Short-term immunosuppression significantly reduced infiltration in all conditions and up to 42 days after implantation. Biocompatibility after intraportal infusion was best for barium-alginate microbeads and poorest for polycation-containing microcapsules. Short- and long-term overgrowth could be significantly reduced by short-term immunosuppression.
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Early Discontinuation of Steroids is Safe and Effective in Pediatric Kidney Transplant Recipients
Pediatric Transplantation.
Aug, 2005 |
Pubmed ID: 16048597 In pediatric kidney transplantation, steroid induced growth retardation and cushingoid features are of particular concern. In children, gradual steroid withdrawal late after kidney transplantation increases the risk of rejection. In this pilot study, we investigated the outcome of pediatric renal transplantation with an early steroid withdrawal protocol. This is a retrospective case-control study of pediatric renal transplants with age-matched historical control. Groups were comparable in terms of HLA matching, donor type and graft ischemia time. In the steroid withdrawal group (SWG, n = 13), induction therapy included mycophenolate mofetil (MMF) and a 5-day course of steroids with Thymoglobulin in 11 and basiliximab in two other patients. In the steroid group (SG, n = 13), in addition to steroids, four patients were given basiliximab, eight were given Thymoglobulin, and one OKT3. Maintenance therapy included tacrolimus (SWG n = 11, SG n = 3) or cyclosporine (SWG n = 2, SG n = 10). Azathioprine was given to all the patients in the SG, except the last two patients of this series who were prescribed MMF. MMF was given to all in the SWG. Patient and graft survival rates were 100% in both groups. In the SWG, no acute rejection episode was detected. In the steroid group, three patients (25%) presented with an acute rejection episode. All but one patient in either group showed immediate graft function. Patients in the steroid-withdrawal group exhibited a significantly higher creatinine clearance at 6 and 12 months post-transplant (95.8 +/- 23.3 vs. 71.3 +/- 21.9, p = 0.03; and 91.3 +/- 21.6 vs. 69.6 +/- 28.6, p = 0.04). In the SWG delta BMI was significantly lower and delta height Z score was significantly higher, and we observed significantly less hyperlipidemia, body disfigurement, and need for anti-hypertensive medication. Early steroid withdrawal in pediatric renal transplant recipients is efficacious and safe and does not increase risk of rejection, preserving optimal growth and renal function, and reducing cardiovascular risk factors.
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Multipotential Nestin and Isl-1 Positive Mesenchymal Stem Cells Isolated from Human Pancreatic Islets
Biochemical and Biophysical Research Communications.
Jul, 2006 |
Pubmed ID: 16713999 Mesenchymal cells in the developing pancreas express the neural stem cell marker nestin and the transcription factor islet-1 (Isl-1). Using defined culture conditions we isolated on a single cell basis nestin producing cells from human pancreatic islets. These cells were immortalized with lentiviral vectors coding for telomerase and mBmi. They are positive for Isl-1 and nestin and have the potential to adopt a pancreatic endocrine phenotype with expression of critical transcription factors including Ipf-1, Isl-1, Ngn-3, Pax4, Pax6, Nkx2.2, and Nkx6.1 as well as the islet hormones insulin, glucagon, and somatostatin. In addition, they can be differentiated into human albumin producing cells in vivo when grafted into a SCID mouse liver. In accordance with a mesenchymal phenotype, the cells were also able to adopt adipocytic or osteocytic phenotypes in vitro. In conclusion, cultured pancreatic islets contain nestin and Isl-1 positive mesenchymal stem cells with multipotential developmental capacity.
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Hilar Early Division of the Hepatic Duct in Living Donor Right Hepatectomy: the Probe-and-clamp Technique
Liver Transplantation : Official Publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society.
Sep, 2006 |
Pubmed ID: 16933234 The division of the hepatic duct is one of the most challenging passages of the donor hepatectomy. We report our experience with the early division, prior to the liver parenchyma resection, of the hepatic duct and the definition of the biliary anatomy with a probe inserted in the proper hepatic duct. From February 2002 to December 2004, 40 donors (25 male, 15 female; mean age 34, range 20-57) underwent right hepatectomy. The yield was a single duct in 24 donors (60%), two ducts in 12 donors (30%), and three ducts in one donor (2.5%), and three donors had aberrant anatomy yielding two ducts (7.5%). By means of a ductoplasty, a single orifice for the recipient biliary anastomosis was obtained in 77.5% of the cases. Three donors (7.5%) suffered a resection surface bile leak. The technique of hepatic duct probing and early division provides a precise definition of the biliary anatomy and facilitates one of the most challenging passages of the donor hepatectomy. This technique should also contribute to maximizing the preservation of the vascular supply of the hepatic duct and the yield of a single orifice for the recipient anastomosis. At a median follow-up of 21 months (range 10-44), neither short- nor long-term complications had been caused by the small donor choledochotomy.
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Aging Correlates with Decreased Beta-cell Proliferative Capacity and Enhanced Sensitivity to Apoptosis: a Potential Role for Fas and Pancreatic Duodenal Homeobox-1
Diabetes.
Sep, 2006 |
Pubmed ID: 16936193 Type 2 diabetes is characterized by a deficit in beta-cell mass, and its incidence increases with age. Here, we analyzed beta-cell turnover in islets from 2- to 3- compared with 7- to 8-month-old rats and in human islets from 53 organ donors with ages ranging from 17 to 74 years. In cultured islets from 2- to 3-month-old rats, the age at which rats are usually investigated, increasing glucose from 5.5 to 11.1 mmol/l decreased beta-cell apoptosis, which was augmented when glucose was further increased to 33.3 mmol/l. In parallel, beta-cell proliferation was increased by both 11.1 and 33.3 mmol/l glucose compared with 5.5 mmol/l. In contrast, in islets from 7- to 8-month-old rats and from adult humans, increasing glucose concentrations from 5.5 to 33.3 mmol/l induced a linear increase in beta-cell death and a decrease in proliferation. Additionally, in cultivated human islets, age correlated positively with the sensitivity to glucose-induced beta-cell apoptosis and negatively to baseline proliferation. In rat islets, constitutive expression of Fas ligand and glucose-induced Fas receptor expression were observed only in 7- to 8-month-old but not in 2- to 3-month-old islets, whereas no age-dependent changes in the Fas/Fas ligand system could be detected in human islets. However, pancreatic duodenal homeobox (PDX)-1 expression decreased with age in pancreatic tissue sections of rats and humans. Furthermore, older rat islets were more sensitive to the high-glucose-mediated decrease in PDX-1 expression than younger islets. Therefore, differences in glucose sensitivity between human and 2- to 3-month-old rat islets may be due to both differences in age and in the genetic background. These data provide a possible explanation for the increased incidence of type 2 diabetes at an older age and support the use of islets from older rats as a more appropriate model to study glucose-induced beta-cell apoptosis.
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Low Concentration of Interleukin-1beta Induces FLICE-inhibitory Protein-mediated Beta-cell Proliferation in Human Pancreatic Islets
Diabetes.
Oct, 2006 |
Pubmed ID: 17003335 High glucose concentrations have a dual effect on beta-cell turnover, inducing proliferation in the short-term and apoptosis in the long-term. Hyperglycemia leads to beta-cell production of interleuking (IL)-1beta in human pancreatic islets. Fas, a death receptor regulated by IL-1beta, is involved in glucose-induced beta-cell apoptosis. Fas engagement can be switched from death signal to induction of proliferation when the caspase 8 inhibitor, FLICE-inhibitory protein (FLIP), is active. Here, we show that IL-1beta at low concentrations may participate in the mitogenic actions of glucose through the Fas-FLIP pathway. Thus, exposure of human islets to low IL-1beta concentrations (0.01-0.02 ng/ml) stimulated proliferation and decreased apoptosis, whereas increasing amounts of IL-1beta (2-5 ng/ml) had the reverse effects. A similarly bimodal induction of FLIP, pancreatic duodenal homeobox (PDX)-1, and Pax4 mRNA expression, as well as glucose-stimulated insulin secretion, was observed. In contrast, Fas induction by IL-1beta was monophasic. Low IL-1beta also induced the IL-1 receptor antagonist (IL-1Ra), suppression of which by RNA interference abrogated the beneficial effects of low IL-1beta. The Fas antagonistic antibody ZB4 and small interfering RNA to FLIP prevented low IL-1beta-stimulated beta-cell proliferation. Consistent with our in vitro results, IL-1beta knockout mice displayed glucose intolerance along with a decrease in islet Fas, FLIP, Pax4, and PDX-1 transcripts. These findings indicate that low IL-1beta levels positively influence beta-cell function and turnover through the Fas-FLIP pathway and that IL-1Ra production prevents harmful effects of high IL-1beta concentrations.
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Human Islet Isolation Outcomes from Pancreata Preserved with Histidine-Tryptophan Ketoglutarate Versus University of Wisconsin Solution
Transplantation.
Oct, 2006 |
Pubmed ID: 17038916 This study was designed to compare Histadine-Tryptophan-Ketogluterate (HTK) with University of Wisconsin (UW) solution. Pancreata from extended criteria donors were flushed and transported with HTK (n=41) or UW (n=45). Isolation outcomes were determined by islet yields, viability and in vitro and in vivo function. Final yields were similar between two groups (HTK: 383,085 vs. UW: 328,514 EIN, P=0.14). In the HTK group, 63.4% (26/41) of isolations resulted in a yield of over 300,000, and in the UW group this was achieved in 46.7% (21/45; P=0.12). Viability results were similar (HTK: 82.9 vs. UW: 82.7%, P=0.93). Stimulation index in the HTK and UW groups were comparable (5.28 vs. 4.91, P=0.62). Ten out of 41 islet preparations in HTK and 4 of 45 in UW group were suitable for clinical transplantation (P=0.05). Our study shows HTK is equivalent to UW solution in the preservation of pancreata for islet isolation.
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Successful Rescue of Refractory, Severe Antibody Mediated Rejection with Splenectomy
Transplantation.
Jan, 2007 |
Pubmed ID: 17220802 Antibody-mediated rejection (AMR) commonly occurs after transplantation of ABO-incompatible and sensitized renal transplant. Treatment regimens commonly include a combination of plasmapheresis (PL) and intravenous immunoglobulin (IVIG). However, some cases of AMR remain refractory to treatment. We report a case series of four patients with AMR refractory to standard therapy (ST) who resolved after splenectomy. Four living donor kidney transplant recipients were diagnosed with AMR. Two patients were ABO incompatible, one was cross-match positive and one had no obvious predisposing factors. After failure of therapy with corticosteroids, PL, IVIG, Thymoglobulin, and Rituximab (three patients) or Campath (one patient), AMR was treated with laparoscopic splenectomy. After an average of 11 days of ST, laparoscopic splenectomy was performed for rescue. The urinary output improved immediately in all patients, serum creatinine levels decreased within 48 hr, and ABO titers fell in the ABO-incompatible patient and the cross-match became negative in the two sensitized patients. Splenectomy may play a role in the treatment of AMR refractory to ST.
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Infectious Complications Associated with the Use of Rituximab for ABO-incompatible and Positive Cross-match Renal Transplant Recipients
Clinical Transplantation.
Sep-Oct, 2007 |
Pubmed ID: 17845637 Immunosuppressive protocols for ABO-incompatible (ABOI) and positive cross-match (PCM) solid organ transplant (SOT) recipients have included the use of rituximab (RTX). Infectious complications (IC) have been reported after the use of RTX for other indications, but have not been well studied in the SOT population. We performed a retrospective review of IC occurring within six months of ABOI and PCM renal transplantation (RT) in recipients receiving RTX. Medical records were reviewed for bloodstream, lung, gastrointestinal tract, allograft, or soft tissue infection. Between July 2001 and December 2004, 34 ABOI or PCM RT were performed at University of Illinois at Chicago, 25 of which received RTX with plasmapheresis and antithymocyte globulin (ATG) (eight ABOI and 17 PCM). Among the RTX recipients, the rate of IC was 48% compared with 11% among historical controls who did not receive RTX (p = 0.107). There were 21 episodes of IC in 13 patients including skin and soft tissue infection (8), bloodstream infection (5), esophagitis (3), peritonitis (3), pneumonia (1), and colitis (1). There was no difference in the rate of rejection, graft survival or patient survival between the two groups. These data suggest that there is a trend toward an increased rate of IC with RTX therapy in ABOI and PCM RT recipients.
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Robotic Distal Pancreatectomy and Nephrectomy for Living Donor Pancreas-kidney Transplantation
Transplantation.
Oct, 2007 |
Pubmed ID: 17984850 Living organ donation is of increasing importance to satisfy the demand of good quality organs for patients remaining for extended periods on the waiting list. While the benefit for the recipient is undeniable, the organ procurement represents an important burden to live donors in terms of invasiveness and long-term consequences. The latter can be minimized with careful donor selection. With the avenue of minimally invasive surgery, and more recently the availability of robotic technology, the surgical trauma can be reduced, the safety increased, and the recovery accelerated. In this case report, we present the first reported combined robotic distal pancreatectomy and left nephrectomy from a live donor. The surgery was performed using the Da Vinci robotic system with four small trocar incisions, and a short infraumbilical midline incision for hand-assistance and extraction of the organ. The donor operation lasted 5 hr and blood loss was only 100 mL. Both donor and recipient had an uncomplicated postoperative course and present with normal endocrine and renal function 3 mo after surgery. In experienced hands, advanced surgical procedures such as combined distal pancreatectomy and left nephrectomy can be safely performed in living donors with minimally invasive robotic surgery, dramatically reduced surgical trauma, and impressive postoperative recovery. The availability of minimally invasive robotic surgery may further increase the willingness for live organ donation from suitable donors.
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Improved Human Pancreatic Islet Purification with the Refined UIC-UB Density Gradient
Transplantation.
Nov, 2007 |
Pubmed ID: 17998877 Human islet isolation outcomes were compared between two purification methods; 32 pancreases were processed by conventional Biocoll purification method (SM, standard method) and 132 pancreases by a refined University of Illinois at Chicago UW/Biocoll method (UIC-UB). There was no difference in donor characteristics between the two study groups. The prepurification equivalent islet number was similar between the groups (359,425+/-40,794 equivalent islet number in SM vs. 370,682+/-17,579 in UIC-UB). SM purified islets were mostly collected in only 2 of 12 fractions (68.9% and 36.3% purity). With the UIC-UB, highly purified islets were collected in 6 of 12 separate fractions (fractions 3-8 with purity of 84.8%, 82.5%, 72.0%, 59.3%, 46.8%, and 36.2%). UIC-UB yielded significantly greater islet yield compared with SM (368,419+/-18,245 vs. 260,908+/-37,835, P=0.017). Islet recovery rate was superior in UIC-UB (84.9% vs. 64.5%, P=0.04). Our study demonstrates a superior recovery of highly pure human pancreatic islets after purification using the refined method of UIC-UB gradient.
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Encapsulation of Human Islets in Novel Inhomogeneous Alginate-ca2+/ba2+ Microbeads: in Vitro and in Vivo Function
Artificial Cells, Blood Substitutes, and Immobilization Biotechnology.
2008 |
Pubmed ID: 18925451 Microencapsulation may allow for immunosuppression-free islet transplantation. Herein we investigated whether human islets can be shipped safely to a remote encapsulation core facility and maintain in vitro and in vivo functionality. In non-encapsulated islets before and encapsulated islets after shipment, viability was 88.3+/-2.5 and 87.5+/-2.7% (n=6, p=0.30). Stimulation index after static glucose incubation was 5.4+/-0.5 and 6.3+/-0.4 (n=6, p=0.18), respectively. After intraperitoneal transplantation, long-term normoglycemia was consistently achieved with 3,000, 5,000, and 10,000 IEQ encapsulated human islets. When transplanting 1,000 IEQ, mice returned to hyperglycemia after 30-55 (n=4/7) and 160 days (n=3/7). Transplanted mice showed human oral glucose tolerance with lower glucose levels than non-diabetic control mice. Capsules retrieved after transplantation were intact, with only minimal overgrowth. This study shows that human islets maintained the viability and in vitro function after encapsulation and the inhomogeneous alginate-Ca(2+)/Ba(2+) microbeads allow for long-term in vivo human islet graft function, despite long-distance shipment.
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Metabolic Syndrome in Pediatric Renal Transplant Recipients: Comparing Early Discontinuation of Steroids Vs. Steroid Group
Pediatric Transplantation.
May, 2010 |
Pubmed ID: 19793225 Steroids have played a valuable role in transplantation as a treatment option. The purpose of this study is to assess the prevalence of MS in pediatric RT patients receiving SG or early SWG; SG discontinued five days after transplantation. We retrospectively reviewed 58 pediatric RT patients between 2000 and 2007. MS criterion was defined as the presence of any three of five criteria: (i) BMI >97th percentile, (ii) hypertension (SBP/DBP > 95th percentile or on medications); (iii) triglycerides > 95thpercentile, (iv) HDL cholesterol < 5th percentile, (v) fasting glucose > 100 mg/dL. Twenty-five patients (43%) received SG and 33 patients (57%) received SWG. The prevalence of MS in SG was 68% compared to 15% in SWG. At six months and one yr after transplantation, mean serum glucose, total cholesterol, and triglycerides were significantly lower in the SWG. The prevalence of hypertension was significantly lower in the SWG, and patients in the SWG received significantly less lipid-lowering and anti-hypertensive medications than SG. Mean BMI percentile was significantly higher in SG one yr after transplantation but not after six months, although always significantly higher in patients with MS (p < 0.05). From this study, we conclude that for pediatric RT patients, cardiovascular risk factors are significantly lower in SG withdrawal groups.
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Highly Purified Versus Filtered Crude Collagenase: Comparable Human Islet Isolation Outcomes
Cell Transplantation.
Mar, 2011 |
Pubmed ID: 21396158 This study was designed to retrospectively compare the impact of crude Sigma V collagenase (Sigma V, n=52) with high-purified Serva NB1 collagenase (Serva NB1, n=42) on human islet isolation outcomes. A three-step filtration was applied to the crude Sigma V to remove endotoxin contamination and impurities; in addition, this process was used as a lot prescreening tool. Isolation outcomes were determined by digestion efficacy, islet yields, purity, viability, glucose-stimulated insulin release, and endotoxin content. The digestion efficacy between Sigma V and Serva NB1 was statistically significant (Sigma V: 64.71% vs. Serva NB1: 69.71%, p=0.0014). However, the islet yields were similar (Sigma V: 23422.58 vs. Serva NB1: 271097 IEq, p=0.23) between groups. There was no significant purity difference observed in fractions with purities greater than 75%. Viability (Sigma V: 93.3% vs. Serva NB1: 94.8%, p=0.061) and stimulation indexes (Sigma V: 3.41 vs. Serva NB1: 2.74, p=0.187) were also similar between the two groups. The impact of cold ischemia and age on the isolation outcome in the Sigma V group was comparable to the Serva NB1 group. The endotoxin content of the final products in the filtered Sigma V group was significantly less than that in the high-purified Serva NB1 group (0.022 EU/ml vs. 0.052 EU/ml, p=0.003). Additionally, in the Sigma V group there was minimal lot to lot variation and no significant loss of enzymatic activity after filtration. These findings indicate that the use of Sigma V or other crude enzyme blends for research pancreata is warranted to reduce isolation costs and increase the amount of islets available for critical islet research. These findings also validate the need for a systematic enzyme analysis to resolve these inconsistencies in overall enzyme quality once and for all.
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Islet Preconditioning Via Multimodal Microfluidic Modulation of Intermittent Hypoxia
Analytical Chemistry.
Feb, 2012 |
Pubmed ID: 22296179 Simultaneous stimulation of ex vivo pancreatic islets with dynamic oxygen and glucose is a critical technique for studying how hypoxia alters glucose-stimulated response, especially in transplant environments. Standard techniques using a hypoxic chamber cannot provide both oxygen and glucose modulations, while monitoring stimulus-secretion coupling factors in real-time. Using novel microfluidic device with integrated glucose and oxygen modulations, we quantified hypoxic impairment of islet response by calcium influx, mitochondrial potentials, and insulin secretion. Glucose-induced calcium response magnitude and phase were suppressed by hypoxia, while mitochondrial hyperpolarization and insulin secretion decreased in coordination. More importantly, hypoxic response was improved by preconditioning islets to intermittent hypoxia (IH, 1 min/1 min 5-21% cycling for 1 h), translating to improved insulin secretion. Moreover, blocking mitochondrial K(ATP) channels removed preconditioning benefits of IH, similar to mechanisms in preconditioned cardiomyocytes. Additionally, the multimodal device can be applied to a variety of dynamic oxygen-metabolic studies in other ex vivo tissues.
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