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.

Human Islet Retransplantation in a Patient with Type I Diabetes

Transplant International : Official Journal of the European Society for Organ Transplantation. Apr, 2002  |  Pubmed ID: 11976743

FLIP Switches Fas-mediated Glucose Signaling in Human Pancreatic Beta Cells from Apoptosis to Cell Replication

Proceedings of the National Academy of Sciences of the United States of America. Jun, 2002  |  Pubmed ID: 12060768

Type 2 diabetes mellitus results from an inadequate adaptation of the functional pancreatic beta cell mass in the face of insulin resistance. Changes in the concentration of glucose play an essential role in the regulation of beta cell turnover. In human islets, elevated glucose concentrations impair beta cell proliferation and induce beta cell apoptosis via up-regulation of the Fas receptor. Recently, it has been shown that the caspase-8 inhibitor FLIP may divert Fas-mediated death signals into those for cell proliferation in lymphatic cells. We observed expression of FLIP in human pancreatic beta cells of nondiabetic individuals, which was decreased in tissue sections of type 2 diabetic patients. In vitro exposure of islets from nondiabetic organ donors to high glucose levels decreased FLIP expression and increased the percentage of apoptotic terminal deoxynucleotidyltransferase-mediated UTP end labeling (TUNEL)-positive beta cells; FLIP was no longer detectable in such TUNEL-positive beta cells. Up-regulation of FLIP, by incubation with transforming growth factor beta or by transfection with an expression vector coding for FLIP, protected beta cells from glucose-induced apoptosis, restored beta cell proliferation, and improved beta cell function. The beneficial effects of FLIP overexpression were blocked by an antagonistic anti-Fas antibody, indicating their dependence on Fas receptor activation. The present data provide evidence for expression of FLIP in the human beta cell and suggest a novel approach to prevent and treat diabetes by switching Fas signaling from apoptosis to proliferation.

Prostaglandin E(1) Protects Human Liver Sinusoidal Endothelial Cell from Apoptosis Induced by Hypoxia Reoxygenation

Microvascular Research. Jul, 2002  |  Pubmed ID: 12074635

Hepatic ischemia-reperfusion injury is an important cause of graft dysfunction after liver transplantation. Liver sinusoidal endothelial cells (LSECs) are particularly sensitive to ischemia-reperfusion injury and undergo apoptosis. This study investigates the protective role of PGE(1) on apoptosis of LSEC during hypoxia-reoxygenation in vitro. Hypothermia-hypoxia followed by reoxygenation triggered LSEC apoptosis, and prostaglandin PGE(1) protected LSEC from apoptosis in a dose-dependent manner. The release of matrix metalloproteinases (MMPs) and nitric oxide (NO) by LSECs were increased after hypoxia reoxygenation. Both the MMP inhibitor BB3103 and the NO inhibitor LNAM effectively decreased LSEC apoptosis, suggesting a separate role of MMPs and NO in hypoxia-reoxygenation-induced LSEC apoptosis. PGE(1) down-regulated NO production by inhibiting the expression of inducible NO synthase in LSEC. PGE(1) also inhibited MMP-2 release from LSEC during hypoxia reoxygenation. These results indicate that the protection of LSECs from apoptosis by PGE(1) in hepatic ischemia-reperfusion injury is mediated by inhibiting inducible NO synthase and MMP release.

Potential Impact of in Situ Liver Splitting on the Number of Available Grafts

Transplantation. Jul, 2002  |  Pubmed ID: 12151735

The potential increase in the number of liver grafts gained from systematically using the technique of splitting optimal organs is still unknown. This study investigates the proportion of donors that should be considered for in situ split-liver harvesting according to strict criteria on which a consensus could be reached easily.

Highly Efficient Lentiviral Vector-mediated Transduction of Nondividing, Fully Reimplantable Primary Hepatocytes

Molecular Therapy : the Journal of the American Society of Gene Therapy. Aug, 2002  |  Pubmed ID: 12161186

Gene therapy is an attractive approach for the treatment of liver disease. We demonstrate that a so-called third-generation human immunodeficiency virus (HIV)-derived vector system can govern the efficient delivery, integration, and stable expression of a transgene into primary human hepatocytes in the complete absence of cell division. We also show that rodent hepatocytes exhibit a significant degree of resistance to HIV vector-mediated transduction, a phenotype that is particularly pronounced in murine hepatocytes and that results from a block in the immediate-early phase of infection. We finally describe a methodology, that allows very high rates of transduction through minimal in vitro manipulation, in which hepatocytes are kept in suspension and reimplanted within a few hours of harvest with a fully preserved engraftment potential. These results have immediate implications for the treatment of liver diseases by the transplantation of genetically modified hepatocytes, an approach that could be applied to a number of hereditary and acquired hepatic disorders.

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.

Arantius' Ligament Approach to the Left Hepatic Vein and to the Common Trunk

Journal of the American College of Surgeons. Nov, 2002  |  Pubmed ID: 12437267

Reduction of Blood Glucose Variability in Type 1 Diabetic Patients Treated by Pancreatic Islet Transplantation: Interest of Continuous Glucose Monitoring

Diabetes Care. Dec, 2002  |  Pubmed ID: 12453970

To compare the glycemic profiles of patients with type 1 diabetes treated with either an implantable insulin pump or pancreas or islet transplantation by the means of the continuous glucose monitoring system (CGMS; Minimed, Sylmar, CA).

An Unusual, Presumably Hepatic Mass

Lancet. Dec 21-28, 2002  |  Pubmed ID: 12504419

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.

Current Status of Islet Cell Transplantation

Advances in Surgery. 2003  |  Pubmed ID: 12953637

Insulin Independence After Conversion to Tacrolimus and Sirolimus-based Immunosuppression in Islet-kidney Recipients

Transplantation. Oct, 2003  |  Pubmed ID: 14557767

Kidney-pancreas Transplantation in a Long-term Non-progressor HIV-infected Recipient

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. May, 2003  |  Pubmed ID: 12752321

With the introduction of highly active antiretroviral therapy (HAART), HIV infection has become a chronic disease with more frequent end-stage organ failures. As a result, the question of transplantation in HIV patients is raised more often. Although still subject to controversies, HIV infection is no longer an absolute contraindication to solid organ transplantation. We report a case of combined kidney-pancreas transplantation in a HIV recipient. HIV has remained stable without any antiviral therapy for up to 2 years after transplantation and has reached criteria for inclusion in the long-term nonprogressor (LTNP) group. Grafted organs demonstrated good function without rejection. This case emphasizes the need to consider LTNP HIV patients as a specific subgroup, when discussing solid organ transplantation. HAART is not required, thus sparing drug interactions and their unique immunological features, such as CCR5 mutation, might prevent rejection. This subgroup of HIV patients should be offered less restricted access to transplantation.

Intra-portal Injection of 400- Microm Microcapsules in a Large-animal Model

Transplant International : Official Journal of the European Society for Organ Transplantation. Jun, 2003  |  Pubmed ID: 12819871

To date, encapsulated grafts have usually been implanted in the peritoneal cavity. This site is, however, not ideal, mainly because of its low blood supply. We have investigated the feasibility of intra-portal injection of (400 microm) microcapsules in the pig. Ten-thousand microcapsules per kilogram body weight were injected into six Large White pigs. Portal pressure, various biological tests, portographies and liver histology were recorded before and at various time points after injection. As a result, portal pressure increased after injection (15+/-2.3 vs 8.7+/-1.7 mmHg) but remained within an acceptable range (<20 mmHg) and returned to normal values at 3 months (8.5+/-3.7 mmHg). During the 3-month follow up, liver function and liver tests remained stable. Portographies showed a homogenous implantation of the capsule, with the portal flow always directed to the liver. At histological examination after 3 months the capsules demonstrated various degrees of fibrosis. We can thus conclude that these results demonstrate that intra-portal injection of microcapsules is feasible in a large-animal model. Hemodynamic, biological and radiological results are similar to those observed in clinical free-islet transplantation.

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.

Changes in Liver Enzymes After Clinical Islet Transplantation

Transplantation. Nov, 2003  |  Pubmed ID: 14627903

Clinical islet transplantation (ITx) shows insulin independence with adequate metabolic control in patients with type 1 diabetes. The aim of this study was to characterize the pattern of elevation in liver enzymes observed after ITx and to investigate any correlation between these elevations and graft characteristics or graft functional outcome.

[Treatment of Insulin-dependent Diabetes: New Therapeutics. Cellular Replacement: Facts and Perspectives]

Bulletin De L'Académie Nationale De Médecine. 2003  |  Pubmed ID: 15146605

The replacement of insulin producing beta cells by islet transplantation can effectively control blood glucose levels in individuals with Type I diabetes. Recent improvements in clinical results were made possible by transplantation of greater islet masses and introduction of new immunosuppressive protocols, which avoid diabetogenicity. Future, widespread clinical application of islet transplantation will depend on the availability of an unlimited source of glucose sensitive, insulin-secreting tissue and less toxic immunosuppressors.

Influence of Pancreas Preservation on Human Islet Isolation Outcomes: Impact of the Two-layer Method

Transplantation. Jul, 2004  |  Pubmed ID: 15257045

Human pancreas preservation for islet transplantation holds additional challenges and considerations compared with whole pancreas transplantation. The purpose of this study was to clarify the limitations of the University of Wisconsin (UW) solution and the potentials of the two-layer method (TLM) for pancreas preservation before human islet isolation.

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.

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.

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.

Cost Analysis of Human Islet Transplantation for the Treatment of Type 1 Diabetes in the Swiss-French Consortium GRAGIL

Diabetes Care. Apr, 2004  |  Pubmed ID: 15047645

To evaluate the cost of islet transplantation in type 1 diabetic patients with a functional renal graft in a multicenter network.

Are Criteria for Islet and Pancreas Donors Sufficiently Different to Minimize Competition?

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. May, 2004  |  Pubmed ID: 15084172

Islet and pancreas transplantation may compete for a limited number of organs. We analyzed records from the national Swiss transplant registry during a 4-year period to investigate the proportion of donors that are suitable for islet and pancreas transplantation. Suitability for pancreas transplantation was mainly defined as: age 10-45 years; weight

Influence of Islet Transportation on Pancreatic Islet Allotransplantation in Type 1 Diabetic Patients Within the Swiss-French GRAGIL Network

Transplantation. Apr, 2004  |  Pubmed ID: 15114103

The influence of islet transportation on pancreatic islet allotransplantation in type 1 diabetic patients was evaluated within the GRAGIL network.

Cadaver Iliac Vein Outflow Reconstruction in Living Donor Right Lobe Liver Transplantation

Journal of the American College of Surgeons. Sep, 2004  |  Pubmed ID: 15325624

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.

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.

Thymoglobulin Induction Protects Liver Allografts from Ischemia/reperfusion Injury

Clinical Transplantation. Aug, 2005  |  Pubmed ID: 16008596

Interventions that minimize hepatic ischemia/reperfusion injury (IRI) can expand the donor organ pool. Thymoglobulin (TG) induction therapy has been shown to ameliorate delayed graft function and possibly decrease IRI in cadaver renal transplants recipients. This controlled randomized trial was designated to assess the ability of TG to protect against IRI in liver transplant recipients.

Increased Risk of Post-transplant Diabetes Mellitus Despite Early Steroid Discontinuation in Hispanic Kidney Transplant Recipients

Clinical Transplantation. Aug, 2005  |  Pubmed ID: 16008600

Early steroid discontinuation (ESD) has been associated with a lower incidence of post-transplant diabetes mellitus (PTDM). We retrospectively reviewed the incidence of PTDM in relation to racial groups in kidney transplant recipients treated with ESD. Between January 2002 and September 2003, 125 consecutive primary adult kidney transplants were performed. Group A (n = 91) had steroids discontinued on postoperative day 6 and maintenance immunosuppression of Tacrolimus and mycophenolate mofetil. Group B (n = 34), received the same immunosuppression but was maintained on steroids indefinitely. Induction consisted of thymoglobulin in African-Americans; all others received Simulect. At 1 yr, patient/graft survival, serum creatinine and rate of acute rejection were similar in both groups. The incidence of PTDM was significantly lower in group A (7%) compared with group B (26%, p = 0.0209). The incidence of PTDM in group A was limited to Hispanic patients with a family history of diabetes mellitus. African-Americans and Caucasians in group A did not experience PTDM (p = 0.005 compared with African-American in group B). Our steroid free protocol nearly eliminated the incidence of PTDM in African-Americans and Caucasians, but was still associated with significant rate of PTDM in Hispanic recipients. Alternative immunosuppression may benefit this population.

Islet Transplantation: Current Status and Future Directions

Current Diabetes Reports. Aug, 2005  |  Pubmed ID: 16033685

Pancreatic islet transplantation has gone a long way to finally enter the armamentarium of today's clinicians for the battle against diabetes. The proof of principle has been made and current clinical islet transplant trials need to further refine this attractive treatment modality. We review the post-Edmonton era, the selection of islet transplant recipients, the production of islet grafts, and the need for immunosuppression and procedure-related risks. The success of islet transplantation and expansion of clinical trials with islet networks are also discussed.

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.

Use of the Splenic Vessels for an ABO Incompatible Renal Transplant in a Patient with Thrombosis of the Vena Cava

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. Sep, 2005  |  Pubmed ID: 16095524

Treatment of Acetaminophen-induced Acute Liver Failure in the Mouse with Conditionally Immortalized Human Hepatocytes

Journal of Hepatology. Dec, 2005  |  Pubmed ID: 16169114

Liver failure is a life threatening condition currently treated by palliative measures and, when applicable, organ transplantation. The use of a bioartificial organ capable of fulfilling the main functions of the liver would represent an attractive alternative. However, the shortage of suitable donor cells, and their limited growth ability have impeded the development of this strategy. We investigated whether lentiviral vectors allow for conditional immortalization of human hepatocytes and whether these immortalized hepatocytes could reverse lethal acute liver failure.

Macrophage Depletion Prolongs Discordant but Not Concordant Islet Xenograft Survival

Transplantation. Mar, 2005  |  Pubmed ID: 15753843

T cells and macrophages play a major role in the rejection of xenografted islets. Depending on the phylogenetic disparity, direct or indirect antigen presentation is predominant. The aim of this study was to analyze in vitro the predominance of direct or indirect presentation by depleting antigen-presenting cells in concordant and discordant xenogeneic combinations. In vivo, we analyzed the effect of macrophage depletion on concordant and discordant islet xenograft survival to assess in which combination this strategy can be used as therapeutic tool.

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.

Routine Left Robotic-assisted Laparoscopic Donor Nephrectomy is Safe and Effective Regardless of the Presence of Vascular Anomalies

Transplant International : Official Journal of the European Society for Organ Transplantation. Aug, 2006  |  Pubmed ID: 16827680

The classic approach to donor nephrectomy consists of preferential procurement of the kidney without vascular anomalies. We studied the effect of routine procurement of the left kidney regardless the presence of multiple arteries on the outcomes of robotic-assisted laparoscopic living donor nephrectomy (LLDN) with particular reference to the incidence of urological complications. From August 2000 to July 2005, 209 left LLDNs were performed. We analyzed the outcomes of donors and recipients in relation to the presence of multiple vessels versus normal anatomy. We divided the patients into two groups: group A (n = 148) with normal vascular anatomy and group B (n = 61) with vascular anomalies. In the donors, no significant difference in conversion to open surgery rate, blood loss, length of stay, was noted between the two groups; operative time and warm ischemia time were slightly higher in group B. One-year patient survival was 98% in both groups while the 1-year graft survival was 96.6% in group A and 96% in group B. Only one urological complication was noted in the group with normal anatomy (0.7%) versus none in the group with multiple arteries. Left kidney procurement using robotic-assisted laparoscopic technique is safe and effective, even in the presence of vascular anomalies.

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.

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.

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.

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.

Living Related Segmental Bowel Transplantation: from Experimental to Standardized Procedure

Annals of Surgery. Nov, 2006  |  Pubmed ID: 17060761

Living donor bowel transplantation has recently emerged as a valuable alternative to cadaver bowel transplant. We herein present our single-center experience with this procedure.

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.

Functional MR Microimaging of Pancreatic Beta-cell Activation

Cell Transplantation. 2006  |  Pubmed ID: 16719054

The increasing incidence of diabetes and the need to further understand its cellular basis has resulted in the development of new diagnostic and therapeutic techniques. Nonetheless, the quest to noninvasively ascertain beta-cell mass and function has not been achieved. Manganese (Mn)-enhanced MRI is presented here as a tool to image beta-cell functionality in cell culture and isolated islets. Similar to calcium, extracellular Mn was taken up by glucose-activated beta-cells resulting in 200% increase in MRI contrast enhancement, versus nonactivated cells. Similarly, glucose-activated islets showed an increase in MRI contrast up to 45%. Although glucose-stimulated Ca influx was depressed in the presence of 100 microM Mn, no significant effect was seen at lower Mn concentrations. Moreover, islets exposed to Mn showed normal glucose sensitivity and insulin secretion. These results demonstrate a link between image contrast enhancement and beta-cell activation in vitro, and provide the basis for future noninvasive in vivo imaging of islet functionality and beta-cell mass.

Cell-compatible Covalently Reinforced Beads Obtained from a Chemoenzymatically Engineered Alginate

Biomaterials. Sep, 2006  |  Pubmed ID: 16750563

A chemoenzymatic strategy has been exploited to make covalently linked alginate beads with high stability. This was achieved by grafting mannuronan (alginate with 100% mannuronic acid (M)) with methacrylate moieties and then performing two enzymatic steps converting M to guluronic acid (G) in alternating sequences (MG-blocks) and in G-blocks. In this way a methacrylate grafted alginate with better gel-forming ability was achieved. Covalent bindings were introduced into the beads by using a photoinitiating system that initiated polymerization of the methacrylate moieties. The covalent links were demonstrated by beads remaining intact after treatment with EDTA. The new chemoenzymatic photocrosslinked (CEPC) beads were compatible with cells with low post-encapsulation ability like C2C12 myoblasts and human pancreatic islets. The islets continued secreting insulin after encapsulation. On contrary, cells with a high post-encapsulation proliferative ability like 293-endo cells died within 2-week post-encapsulation. The exceptional stability and the cell compatibility of the new CEPC beads make them interesting as bioreactors for delivering therapeutic proteins in future applications.

A Case of Pancreatic Islet Cell Transplantation in a Patient with Situs Ambiguous: Anatomical and Radiological Considerations

Seminars in Interventional Radiology. Mar, 2007  |  Pubmed ID: 21326735

Pancreatic islet cell transplantation is an evolving treatment of severe, refractory type 1 diabetes that has been gaining more use, particularly after one year rates of insulin independence post-transplantation were found to approach 80% under the Edmonton protocol. Islet cell transplantation involves percutaneous delivery of harvested allogeneic β cells into the portal venous circulation for implantation into the liver. We present the case of a 35-year-old woman with type 1 diabetes and situs ambiguous with left isomerism and resultant variant anatomy of her portal venous anatomy who underwent islet cell transplantation, which, to our knowledge, has not been previously reported.

'Prope' Tolerance in a Noncompliant Living Related Small Bowel Transplant Recipient After Severe Rejection

Transplantation. Jan, 2007  |  Pubmed ID: 17220796

Advances in immunosuppression and surgical technique have greatly improved patient outcomes after intestinal transplantation. However, the procedure remains one of the most challenging among solid organ transplantation as a result of the high rate of acute rejection, sepsis, and posttransplantation lymphoproliferative disorder. Recently, clinical trials to explore tolerance protocols in humans have been initiated, including small bowel transplant recipients, with results not always reproducible. The concept of operational tolerance is more meaningful in the clinical setting when physiological stability of graft function is achieved in the absence of maintenance immunosuppression. We report the intriguing case of a living related small bowel transplant recipient who developed clinical "prope" tolerance to the graft after treatment of severe acute rejection despite continuous noncompliance with immunosuppressive therapy.

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.

De Novo Sirolimus-based Immunosuppression After Liver Transplantation for Hepatocellular Carcinoma: Long-term Outcomes and Side Effects

Transplantation. May, 2007  |  Pubmed ID: 17496530

We report long-term outcomes and side effects after transplantation for hepatocellular carcinoma (HCC) using de novo, sirolimus-based immunosuppression (IS).

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.

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.

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.

Transcription Factor 7-like 2 Regulates Beta-cell Survival and Function in Human Pancreatic Islets

Diabetes. Mar, 2008  |  Pubmed ID: 18071026

Type 2 diabetes is characterized by impaired insulin secretion in response to increased metabolic demand. This defect in beta-cell compensation seems to result from the interplay between environmental factors and genetic predisposition. Genome-wide association studies reveal that common variants in transcription factor 7-like 2 (TCF7L2) are associated with increased risk of type 2 diabetes. The aim of the present study was to establish whether TCF7L2 plays a role in beta-cell function and/or survival.

Electrolyte Imbalances in Pediatric Living Related Small Bowel Transplantation

Transplantation. Jan, 2008  |  Pubmed ID: 18212626

Pediatric small bowel transplantations are associated with pronounced electrolyte disturbances in the postoperative period. We investigated the pattern of electrolyte disturbances with regard to enteral malabsorption, renal compensation, and the influence of immunosuppression.

Combined Living-related Segmental Liver and Bowel Transplantation for Megacystis-microcolon-intestinal Hypoperistalsis Syndrome

Journal of Pediatric Surgery. Feb, 2008  |  Pubmed ID: 18280270

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is the most severe form of functional intestinal obstruction in the newborn. To date, multivisceral transplantation has been the only accepted treatment modality for these patients, and the results have met with marginal success. We report the first case of a patient affected by MMIHS and cholestatic liver failure treated by a combined living-related liver and intestinal transplant (CLRLITx).

Increased Albumin Concentration Reduces Apoptosis and Improves Functionality of Human Islets

Artificial Cells, Blood Substitutes, and Immobilization Biotechnology. 2008  |  Pubmed ID: 18293163

Providing sufficient islet mass is important for successful islet transplantation. Apoptosis plays a major role in post-isolation islet cell death, and prevention of apoptosis could improve transplant outcomes. The purpose of this study was to determine whether increased concentration of human albumin (HA) in pre-transplantation culture of human islets would reduce apoptosis. Human islets were cultured in CMRL with 1.5 or 5% of HA for 24 h and apoptosis was evaluated indirectly by measuring caspase 3 activity and tetramethylrhodamine-ethyl-ester (TMRE) in dissociated islets. Islet function and viability were evaluated. Islets cultured in higher albumin concentration presented with lower caspase 3 activity (43.9 +/- 3.9 vs. 67.4 +/- 11.1, p = 0.011), and had increased insulin secretory capacity (Stimulation index 3.76 +/- 0.91 vs 1.23 +/- 0.21, p = 0.023). We conclude that an increase in albumin concentration can prevent apoptosis in isolated human islets. These findings may have implications for islet transplant outcomes.

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.

Reported Isolated Pancreas Rejection is Associated with Poor Kidney Outcomes in Recipients of a Simultaneous Pancreas Kidney Transplant

Transplantation. Nov, 2008  |  Pubmed ID: 19005404

We hypothesized that many reported and presumed isolated pancreas acute rejection episodes in simultaneous pancreas kidney patients may in fact be missed concordant kidney acute rejection episodes.

Reconstruction of Two Bile Ducts in a Cloaca Fashion in Living Donor Liver Transplantation

International Surgery. Sep-Oct, 2008  |  Pubmed ID: 19943431

The presence of two or more hepatic ducts for biliary anastomosis in adult-to-adult right liver transplantation is not uncommon. In the case described here, the graft had two hepatic ducts: one corresponded anatomically to a normal right hepatic duct and the other ran parallel to the proper hepatic duct and drained into its distal to the cystic duct. Because of the small diameter of both duct orifices and the favorable length of the ducts, a cloaca type reconstruction was performed. This allowed the construction of a single and larger orifice for the biliary anastomosis. In case of multiple hepatic ducts of smaller caliber, this technique represents a practical and effective hepatoplasty allowing a single larger anastomosis in the recipient.

Living Donor Liver Graft Salvage After Rupture of Hepatic Artery Pseudoaneurysm

International Surgery. Sep-Oct, 2008  |  Pubmed ID: 19943434

Hepatic artery pseudoaneurysm (HAP) is an uncommon but life-threatening complication of liver transplantation (LTx). It is often associated with a local infection. Prompt diagnosis and intervention are necessary. We report the first occurrence of such complication in the setting of adult living donor liver transplant. A 48-year-old female with primary sclerosing cholangitis underwent living donor right lobe LTx. Her postoperative course was uneventful. A month later, she developed massive gastrointestinal bleeding, with negative endoscopy and angiography. She rebled 2 weeks later, and an HAP was shown on angiography. On exploration, she was found to have an HAP caused by bile leakage from an accessory bile duct and a dissection of the native artery, likely a result of the angiography. The liver was revascularized using a cadaveric iliac artery conduit between the donor hepatic artery and the aorta, and the hepaticojejunostomy was reconstructed. Biliary complications are the most frequent complications in living donor LTx. A clinically silent bile leak can cause an HAP, resulting in massive gastrointestinal bleeding. Surgical repair and biliary reconstruction can yield an excellent clinical result.

Small Interfering RNA-mediated Suppression of Proislet Amyloid Polypeptide Expression Inhibits Islet Amyloid Formation and Enhances Survival of Human Islets in Culture

Diabetes. Nov, 2008  |  Pubmed ID: 18694973

Islet amyloid, formed by aggregation of the beta-cell peptide islet amyloid polypeptide (IAPP; amylin), is a pathological characteristic of pancreatic islets in type 2 diabetes. Toxic IAPP aggregates likely contribute to the progressive loss of beta-cells in this disease. We used cultured human islets as an ex vivo model of amyloid formation to investigate whether suppression of proIAPP expression would inhibit islet amyloid formation and enhance beta-cell survival and function.

ABO Incompatible Renal Transplantation in an HIV-seropositive Patient

Transplantation. Jul, 2008  |  Pubmed ID: 18622297

To date, there have been no reports of successful ABO blood group incompatible renal transplantation in HIV patients. We describe a case of a 47-year-old African American man with end-stage renal disease secondary to HIV-induced nephropathy who underwent a live unrelated (spouse) donor ABO blood group incompatible transplant using an intravenous immunoglobulin/plasmapheresis preconditioning regimen with interleukin-2 receptor antagonist induction along with tacrolimus and mycophenolate mofetil maintenance. The postoperative course was complicated by two acute cellular rejection (Banff Ia) episodes that were successfully managed with corticosteroid boluses and the addition of corticosteroids to maintenance immunosuppression. Antibody-mediated rejection was not observed on biopsy. The patient reached a serum creatinine nadir of 2.0 mg/dL on postoperative day 20, which has now been maintained for 170 days. His current CD4 count was 410 cells/microL.

Robotic-assisted Laparoscopic Distal Pancreatectomy of a Redo Case Combined with Autologous Islet Transplantation for Chronic Pancreatitis

Pancreas. Jan, 2009  |  Pubmed ID: 19106750

Living Donor Kidney Transplantation Across Positive Crossmatch: the University of Illinois at Chicago Experience

Transplantation. Jan, 2009  |  Pubmed ID: 19155983

To increase living donation for kidney transplantation, we investigated desensitization of recipients with positive crossmatch against a potential living donor.

CXCL10 Impairs Beta Cell Function and Viability in Diabetes Through TLR4 Signaling

Cell Metabolism. Feb, 2009  |  Pubmed ID: 19187771

In type 1 and type 2 diabetes (T1/T2DM), beta cell destruction by apoptosis results in decreased beta cell mass and progression of the disease. In this study, we found that the interferon gamma-inducible protein 10 plays an important role in triggering beta cell destruction. Islets isolated from patients with T2DM secreted CXCL10 and contained 33.5-fold more CXCL10 mRNA than islets from control patients. Pancreatic sections from obese nondiabetic individuals and patients with T2DM and T1DM expressed CXCL10 in beta cells. Treatment of human islets with CXCL10 decreased beta cell viability, impaired insulin secretion, and decreased insulin mRNA. CXCL10 induced sustained activation of Akt, JNK, and cleavage of p21-activated protein kinase 2 (PAK-2), switching Akt signals from proliferation to apoptosis. These effects were not mediated by the commonly known CXCL10 receptor CXCR3 but through TLR4. Our data suggest CXCL10 as a binding partner for TLR4 and as a signal toward beta cell failure in diabetes.

Microfluidic Device for Multimodal Characterization of Pancreatic Islets

Lab on a Chip. Jan, 2009  |  Pubmed ID: 19209341

A microfluidic device to perfuse pancreatic islets while simultaneously characterizing their functionality through fluorescence imaging of the mitochondrial membrane potential and intracellular calcium ([Ca(2+)](i)) in addition to enzyme linked immunosorbent assay (ELISA) quantification of secreted insulin was developed and characterized. This multimodal characterization of islet function will facilitate rapid assessment of tissue quality immediately following isolation from donor pancreas and allow more informed transplantation decisions to be made which may improve transplantation outcomes. The microfluidic perfusion chamber allows flow rates of up to 1 mL min(-1), without any noticeable perturbation or shear of islets. This multimodal quantification was done on both mouse and human islets. The ability of this simple microfluidic device to detect subtle variations in islet responses in different functional assays performed in short time-periods demonstrates that the microfluidic perfusion chamber device can be used as a new gold standard to perform comprehensive islet analysis and obtain a more meaningful predictive value for islet functionality prior to transplantation into recipients, which is currently difficult to predict using a single functional assay.

Lessons Learned in Pediatric Small Bowel and Liver Transplantation from Living-related Donors

Transplantation. Apr, 2009  |  Pubmed ID: 19352122

Children are the primary candidates for intestinal transplant with more than 70% requiring a combined liver-bowel transplant. We report our single-center experience with living donor intestinal transplantation (LDITx) and combined living donor intestinal and liver transplant (CLDILTx) in pediatric patients.

Early Intra-abdominal Infections Associated with Orthotopic Liver Transplantation

Transplantation. Jun, 2009  |  Pubmed ID: 19502964

Postoperative infections remain a significant problem among liver transplant recipients (LTRs). An early cause of morbidity after liver transplantation is intra-abdominal infection (IAI) about which there are limited data.

Case Report: Diabetic Myonecrosis of the Neck Complicated by Infection in an Islet Transplanted Patient

Journal of Diabetes and Its Complications. Mar-Apr, 2009  |  Pubmed ID: 18358751

Diabetic muscle infarction, also known as diabetic myonecrosis, is an uncommon neuromuscular complication of longstanding diabetes. It usually involves the thigh or calf muscles. Patients typically present with severe pain in the affected area. This complication is more often seen in middle-aged diabetic patients with poorly controlled glycemia. We describe a 38-year-old female Type 1 diabetic patient who developed acute neck pain 3 weeks following islet transplantation.

Staged Approach for Abdominal Wound Closure Following Combined Liver and Intestinal Transplantation from Living Donors in Pediatric Patients

Pediatric Transplantation. Mar, 2009  |  Pubmed ID: 18537902

Primary closure of the abdominal wall after combined liver and intestine transplantation from a living donor into a pediatric patient is usually not possible, because of the size of the donor organ, graft edema, and preexisting scars or stomas of the abdominal wall. Closure under tension may lead to abdominal compartment syndrome with vascular compromise and necrosis of the transplanted organ. We describe our experience of abdominal wound closure after liver and intestinal transplant in the pediatric patient using a staged approach. From February 2003 to June 2006, we managed five pediatric liver and intestinal living donor transplant recipients. Because of the large post-transplantation abdominal wall defect, a staged technique of abdominal wound closure was utilized. Initially, an absorbable Polygalactin mesh was sutured around the layer of the defect. As soon as adequate granulation tissue was formed over the mesh a STSG was applied. From the wound stand point all five patients were managed successfully with staged wound closure after transplantation. Granulation tissue filled and covered the mesh within 7.6 wk. A STSG was then used to cover the defect. All infants recovered well and none had a significant wound complication in the immediate post-operative period following STSG. At a mean follow-up of 24 months only one patient developed an entero-cutaneous fistula five months post-transplant. Staged abdominal wall coverage with the use of Polygalactin mesh followed by STSG is a simple and effective technique. A closed wound is achieved in a timely fashion with protection of the viscera. Residual ventral hernia will need to be managed in the future with one of several reconstructive techniques.

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.

Laparoscopic and Robotic Donor Pancreatectomy for Living Donor Pancreas and Pancreas-kidney Transplantation

Journal of Hepato-biliary-pancreatic Sciences. Mar, 2010  |  Pubmed ID: 19806301

Pancreas transplantation is a widely accepted procedure that can efficiently restore euglycemia and prevent progression of complications. In most instances, the limiting factor for deceased donor organ transplantation is the availability and quality of the available organs. Living donor pancreas transplant was introduced at the University of Minnesota in 1979. Because of the potential risks for the donor and the technical challenges in the recipient operation, this procedure has not become very popular since then. In 1999, in the attempt to decrease the morbidity associated with open distal pancreatectomy, the first laparoscopic donor distal pancreatectomy with hand-assisted technique was performed at the same institution. In 2000, the FDA approved the robotic surgical system Da Vinci for general use. Since then, the system has been extensively used at our institution to perform living donor nephrectomy. The only case reported worldwide of robotic distal pancreatectomy and nephrectomy for living donor pancreas-kidney transplantation was successfully performed by our team in 2006 at the University of Illinois at Chicago and proved as a promising technique. The application of minimally invasive techniques has allowed an increased acceptance of the procedure among potential donors and may, therefore, increase the number of donors for this life-saving transplant. The initial results are encouraging and clearly prove feasibility.

5'-AZA Induces Ngn3 Expression and Endocrine Differentiation in the PANC-1 Human Ductal Cell Line

Biochemical and Biophysical Research Communications. Jan, 2010  |  Pubmed ID: 19913512

Neurogenin 3 is necessary for endocrine cell development in the embryonic pancreas and has been shown to induce transdifferentiation duct cells from adult pancreas toward a neuro-endocrine phenotype. Here we discovered that the demethylating agent 5'-Azadeoxycytidine (AZA) induced Ngn3 expression and endocrine differentiation from the PANC-1 human ductal cell line. The expression of markers specific to mature islet cells, i.e., glucagon and somatostatin, was also observed. In addition, we demonstrated that growth factors (betacellulin and soluble factors released during pancreas embryogenesis) increased the level of maturation. Our studies revealed that the PANC-1 model system may provide a basis for elucidating the ductal/endocrine differentiation.

Microfluidic Perifusion and Imaging Device for Multi-parametric Islet Function Assessment

Biomedical Microdevices. Jun, 2010  |  Pubmed ID: 20300858

A microfluidic islet perifusion device was developed for the assessment of dynamic insulin secretion of multiple pancreatic islets and simultaneous fluorescence imaging of calcium influx and mitochondrial potential changes. The fanned out design of the second generation device optimized the efficient mixing and uniform distribution of rapid alternating solutions in the perifusion chamber and allowed for the generation of reproducible glucose gradients. Simultaneous imaging of calcium influx and mitochondrial potential changes in response to glucose stimulation showed high signal-noise ratio and spatial-temporal resolution. These results suggest that this system can be used for detailed study of the endocrine function of pancreatic islets with simultaneous imaging of intracellular ion fluxes and mitochondrial membrane potential changes. This tool can be used for quality assessment of islets preparation before transplantation and for in vitro studies of islet function.

Interleukin-2 Receptor Blockade with Humanized Monoclonal Antibody for Solid Organ Transplantation

Expert Opinion on Biological Therapy. Jun, 2010  |  Pubmed ID: 20415630

Induction therapy has reduced the incidence of acute rejection compared with historical standards. The potency of currently available induction immunosuppression is not without risk and should be carefully considered. Induction with daclizumab, an IL-2 receptor antagonist, has been used safely and effectively for over 10 years across different transplant types. As a result of daclizumab use, transplant centers are able to implement steroid-sparing or calcineurin minimization protocols. Unfortunately, the manufacturing costs have resulted in withdrawal of this agent from the market reducing the options for patients undergoing transplantation.

Size-based Separation and Collection of Mouse Pancreatic Islets for Functional Analysis

Biomedical Microdevices. Oct, 2010  |  Pubmed ID: 20549367

Islet size has recently been demonstrated to be an important factor in determining human islet transplantation outcomes. In this study, a multi-layered microfluidic device was developed and quantified for size-based separation of a heterogeneous population of mouse islets. The device was fabricated using standard soft lithography and polydimethylsiloxane (PDMS). Size-based separation was first demonstrated via injection of a heterogeneous population of glass beads between 50-300 microm in diameter which were separated into five sub-populations based on their diameter. Next, a heterogeneous population of mouse pancreatic islets, between 50-250 microm in diameter was separated into four sub-populations. Throughout this process the islets remained intact without any signs of damage, as indicated by cell viability staining. Islet glucose-stimulated insulin secretion of each sub-population of islets was also evaluated demonstrating that islets smaller than 150 microm have superior stimulation indexes (SI) compared to islets larger than 150 microm. In this study, we found that islets between 100 microm and 150 microm in diameter had the greatest SI value in a heterogeneous population of islets.

The Humanized NOD/SCID Mouse As a Preclinical Model to Study the Fate of Encapsulated Human Islets

The Review of Diabetic Studies : RDS. 2010  |  Pubmed ID: 20703439

Despite encouraging results in animal models, the transplantation of microencapsulated islets into humans has not yet reached the therapeutic level. Recent clinical trials using microencapsulated human islets in barium alginate showed the presence of dense fibrotic overgrowth around the microcapsules with no viable islets. The major reason for this is limited understanding of what occurs when encapsulated human islets are allografted. This warrants the need for a suitable small animal model. In this study, we investigated the usefulness of NOD/SCID mice reconstituted with human PBMCs (called humanized NOD/SCID mice) as a preclinical model. In this model, human T cell engraftment could be achieved, and CD45+ cells were observed in the spleen and peripheral blood. Though the engrafted T cells caused a small fibrotic overgrowth around the microencapsulated human islets, this failed to stop the encapsulated islets from functioning in the diabetic recipient mice. The ability of encapsulated islets to survive in this mouse model might partly be attributed to the presence of Th2 cytokines IL-4 and IL-10, which are known to induce graft tolerance. In conclusion, this study showed that the hu-NOD/SCID mouse is not a suitable preclinical model to study the allograft rejection mechanisms of encapsulated human islets. As another result, the maintained viability of transplanted islets on the NOD/SCID background emphasized a critical role of protective mechanisms in autoimmune diabetes transplanted subjects due to specific immunoregulatory effects provided by IL-4 and IL-10.

Modified Gold Nanoparticle Vectors: a Biocompatible Intracellular Delivery System for Pancreatic Islet Cell Transplantation

Surgery. Oct, 2010  |  Pubmed ID: 20800254

Islet transplantation is an emerging therapy for type 1 diabetes mellitus with variable success. Molecular therapeutics is a promising approach to improve islet graft function and transplant outcomes. Traditional delivery vectors, however, have poor cell penetration and generally lead to compromised islet function. Modified gold nanoparticles represent a potential alternative in that they are taken up into cells efficiently and have unique binding properties. The objective of this study was to investigate whether gold nanoparticles can transfect islets uniformly without compromising cellular function.

Current Status of Living Donor Small Bowel Transplantation

Current Opinion in Organ Transplantation. Jun, 2010  |  Pubmed ID: 20445448

To analyze the current status of living donor intestinal transplantation (LDIT) as a treatment option for intestinal failure.

Application of Microfluidic Technology to Pancreatic Islet Research: First Decade of Endeavor

Bioanalysis. Oct, 2010  |  Pubmed ID: 21083325

β-cells respond to blood glucose by secreting insulin to maintain glucose homeostasis. Perifusion enables manipulation of biological and chemical cues in elucidating the mechanisms of β-cell physiology. Recently, microfluidic devices made of polydimethylsiloxane and Borofloat glass have been developed as miniaturized perifusion setups and demonstrated distinct advantages over conventional techniques in resolving rapid secretory and metabolic waveforms intrinsic to β-cells. In order to enhance sensing and monitoring capabilities, these devices have been integrated with analytical tools to increase assay throughput. The spatio-temporal resolutions of these analyses have been improved through enhanced flow control, valves and compartmentalization. For the first time, this review provides an overview of current devices used in islet studies and analyzes their strengths and experimental suitability. To realize the potential of microfluidic islet applications, it is essential to bridge the gap in design and application between engineers and biologists through the creation of standardized bioassays and user-friendly interfaces.

Neutralizing Interleukin-1beta (IL-1beta) Induces Beta-cell Survival by Maintaining PDX1 Protein Nuclear Localization

The Journal of Biological Chemistry. May, 2011  |  Pubmed ID: 21393239

The transcription factor PDX1 plays a critical role during β-cell development and in glucose-induced insulin gene transcription in adult β-cells. Acute glucose exposure leads to translocalization of PDX1 to the nucleoplasm, whereas under conditions of oxidative stress, PDX1 shuttles from the nucleus to the cytosol. Here we show that cytosolic PDX1 expression correlated with β-cell failure in diabetes. In isolated islets from patients with type 2 diabetes and from diabetic mice, we found opposite regulation of insulin and PDX1 mRNA; insulin was decreased in diabetes, but PDX1 was increased. This suggests that elevated PDX1 mRNA levels may be insufficient to regulate insulin. In diabetic islets, PDX1 protein was localized in the cytosol, whereas in non-diabetic controls, PDX1 was in the nucleus. In contrast, overexpression of either IL-1 receptor antagonist or shuttling-deficient PDX1 restored β-cell survival and function and PDX1 nuclear localization. Our results show that nuclear localization of PDX1 is essential for a functional β-cell and provides a novel mechanism of the protective effect of IL-1 receptor antagonist on β-cell survival and function.

A Recommended Laparoscopic Procedure for Implantation of Microcapsules in the Peritoneal Cavity of Non-human Primates

The Journal of Surgical Research. Jun, 2011  |  Pubmed ID: 21435661

The anatomical spatial distribution of microencapsulated islets transplanted into the peritoneal cavity of large animals remains a relatively unexplored area of study. In this study, we developed a new implantation approach using laparoscopy in order to avoid microcapsule amalgamation. This approach constitutes a clinically relevant method, which can be used to evaluate the distribution and in vivo biocompatibility of various types of transplanted microcapsules in the future.

Long-term Follow-up in Adult Living Donors for Combined Liver/bowel Transplant in Pediatric Recipients: a Single Center Experience

Pediatric Transplantation. Jun, 2011  |  Pubmed ID: 21585630

Pediatric candidates for combined liver/bowel transplant (LBTx) experience a very high mortality on the cadaver waiting list. Our transplant center has successfully used adult living donors to treat pediatric candidates for LBTx. We report the long-term follow-up of this unique cohort of organ donors. The charts of six adult donors for LBTx performed between 2004 and 2007 were reviewed. All the pertinent clinical data were carefully reviewed and integrated with phone interviews of all donors. A total of six children (average age 13.5 months) received living donor LBTx. Average follow-up for the donors was 42 months (range 29-51). The donors' median age was 25 yr (19-32); five women and one man. The average median hospital stay was nine days. There were no peri-operative complications. At present all donors remain in good health. Three of the five mothers became pregnant after donation. Five of the six children are currently alive and well whereas one died with functioning grafts six months post-transplant due to plasmoblastic lymphoma. Living donor LBTx is an effective therapy for combined hepatic and intestinal failure in children less than five yr. The donor operation can be performed with minimal morbidity.

Effect of Prolonged Gelling Time on the Intrinsic Properties of Barium Alginate Microcapsules and Its Biocompatibility

Journal of Microencapsulation. 2011  |  Pubmed ID: 21827357

Pericapsular fibrotic overgrowth (PFO) may be attributed to an immune response against microcapsules themselves or to antigen shedding through microcapsule pores from encapsulated islet tissue. Modification of microcapsules aimed at reducing pore size should prevent PFO and improve graft survival. This study investigated the effect of increased gelling time (20 vs. 2 min) in barium chloride on intrinsic properties of alginate microcapsules and tested their biocompatibility in vivo. Prolonged gelling time affected neither permeability nor size of the microcapsules. However, prolonged gelling time for 20 min produced brittle microcapsules compared to 2 min during compression test. Encapsulation of human islets in both types of microcapsules affected neither islet viability nor function. The presence of PFO when transplanted into a large animal model such as baboon and its absence in small animal models such as rodents suggest that the host immune response towards alginate microcapsules is species rather than alginate specific.

Dual Microfluidic Perifusion Networks for Concurrent Islet Perifusion and Optical Imaging

Biomedical Microdevices. Aug, 2011  |  Pubmed ID: 21850483

This study explores a new class of duplex microfluidic device which utilizes a dual perifusion network to simultaneously perform live-cell optical imaging of physiological activities and study insulin release kinetics on two islet populations. This device also incorporates on-chip staggered herringbone mixers (SHMs) to increase mixing efficiency and facilitate the generation of user-defined chemical gradients. Mouse islets are used to simultaneously measure dynamic insulin release, changes in mitochondrial potentials, and calcium influx in response to insulin secretagogues (glucose and tolbutamide), and show a high signal-to-noise ratio and spatiotemporal resolution of all measured parameters for both perifusion chambers. This system has many potential applications for studying β-cell physiology and pathophysiology, as well as for therapeutic drug screening. This dual perifusion device is not limited to islet studies and could easily be applied to other tissues and cells without major modifications.

Effect of Alginate Encapsulation on the Cellular Transcriptome of Human Islets

Biomaterials. Nov, 2011  |  Pubmed ID: 21889795

Encapsulation of human islets may prevent their immune rejection when transplanted into diabetic recipients. To assist in understanding why clinical outcomes with encapsulated islets were not ideal, we examined the effect of encapsulation on their global gene (mRNA) and selected miRNAs (non-coding (nc)RNA) expression. For functional studies, encapsulated islets were transplanted into peritoneal cavity of diabetic NOD-SCID mice. Genomics analysis and transplantation studies demonstrate that islet origin and isolation centres are a major source of variation in islet quality. In contrast, tissue culture and the encapsulation process had only a minimal effect, and did not affect islet viability. Microarray analysis showed that as few as 29 genes were up-regulated and 2 genes down-regulated (cut-off threshold 0.1) by encapsulation. Ingenuity analysis showed that up-regulated genes were involved mostly in inflammation, especially chemotaxis, and vascularisation. However, protein expression of these factors was not altered by encapsulation, raising doubts about the biosignificance of the gene changes. Encapsulation had no effect on levels of islet miRNAs. In vivo studies indicate differences among the centres in the quality of the islets isolated. We conclude that microencapsulation of human islets with barium alginate has little effect on their transcriptome.

Long-term Metabolic and Immunological Follow-up of Nonimmunosuppressed Patients with Type 1 Diabetes Treated with Microencapsulated Islet Allografts: Four Cases

Diabetes Care. Nov, 2011  |  Pubmed ID: 21926290

To assess long-term metabolic and immunological follow-up of microencapsulated human islet allografts in nonimmunosuppressed patients with type 1 diabetes (T1DM).

Segmental Intestinal Autotransplantation After Extensive Enterectomy for Removal of Large Intra-abdominal Desmoid Tumors of the Mesentery Root: Initial Experience

Surgery. Oct, 2011  |  Pubmed ID: 21982069

Pulmonary Sequestration with CCAM Type II Appearing As Adrenal Tumor Protruding Through a Bochdalek Hernia

International Journal of Surgical Pathology. Apr, 2011  |  Pubmed ID: 18701512

A case of a pulmonary sequestration, which almost exclusively consisted of a congenital cystic adenomatoid malformation type II located subdiaphragmatically in the left retroperitoneal area, is reported. This case, in a 24-year-old male patient, is unique in that it appeared as an adrenal incidentaloma and extended through a Bochdalek hernia into the pleural space. It was discovered upon routine ultrasound screening for hepatocellular carcinoma in a patient with a carrier state for hepatitis B. Diagnosis was established only upon histological analysis of the surgically removed tumor after staining with hematoxylin and eosin as well as surfactant A and B. The location of the tumor may indicate that it was formed by an entrapment of a lung bud by the developing diaphragm. This appearance may give us insight into the formation of such tumors. It also highlights the difficulty of diagnosing subdiaphragmatic retroperitoneal tumors without histological examination.

Functional Capacity of Human Islets After Long-distance Shipment and Encapsulation

Pancreas. Mar, 2011  |  Pubmed ID: 20966806

Human islets produced at an isolation center are shipped to researchers, usually taking short periods to arrive at their destination. In this study, we investigated whether human islets after long-distance shipment across the Pacific Ocean for 2 to 3 days and encapsulation could maintain their functionality.

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.

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.

Calibrated Extra-anatomic Hepatic Arterial Reconstruction in Living Donor Liver Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. Jan, 2012  |  Pubmed ID: 21985359

The Effect of Small Bowel Living Donation on Donor Lipid Profile

Transplant International : Official Journal of the European Society for Organ Transplantation. Jan, 2012  |  Pubmed ID: 21988403

Robot-assisted Right Lobe Donor Hepatectomy

Transplant International : Official Journal of the European Society for Organ Transplantation. Jan, 2012  |  Pubmed ID: 22029717

Recent advances in robotic surgical technology have enabled application to complex surgical procedures. Following extensive institutional experience with major robotic liver resections, we determined that it was safe to apply this technology to right lobe donor hepatectomy (RLDH). The procedure was performed using the Da Vinci Robotic Surgical System, in an entirely minimally invasive fashion, during which the liver graft was safely extracted through a limited lower abdominal incision. Both donor and recipient recovered well, without acute complications. To our knowledge, this is the first case reported in the literature. The technical feasibility of this minimally invasive approach is demonstrated, exemplifying the novel exciting opportunities offered by robotic technology.

Rescue Splenectomy in a Case of Humoral Rejection in ABO-incompatible Simultaneous Liver-kidney Transplantation

Transplantation. Jan, 2012  |  Pubmed ID: 22234314

Systematic Prevention of Bubble Formation and Accumulation for Long-term Culture of Pancreatic Islet Cells in Microfluidic Device

Biomedical Microdevices. Jan, 2012  |  Pubmed ID: 22252566

Reliable long-term cell culture in microfluidic system is limited by air bubble formation and accumulation. In this study, we developed a bubble removal system capable of both trapping and discharging air bubbles in a consistent and reliable manner. Combined with PDMS (Polydimethylsiloxane) hydrophilic surface treatment and vacuum filling, a microfluidic perifusion system equipped with the bubble trap was successfully applied for long-term culture of mouse pancreatic islets with no bubble formation and no flow interruption. In addition to demonstrating normal cell viability and islet morphology, post-cultured islets exhibited normal insulin secretion kinetics, intracellular calcium signaling, and changes in mitochondrial potentials in response to glucose challenge. This design could be easily adapted by other microfluidic systems due to its simple design, ease of fabrication, and portability.