Frédéric Ris

Glucose-induced β cell production of IL-1β contributes to glucotoxicity in human pancreatic islets

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.

Clinical Magnetic Resonance Imaging of Pancreatic Islet Grafts After Iron Nanoparticle Labeling

There is a crucial need for noninvasive assessment tools after cell transplantation. This study investigates whether a magnetic resonance imaging (MRI) strategy could be clinically applied to islet transplantation. The purest fractions of seven human islet preparations were labeled with superparamagnetic iron oxide particles (SPIO, 280 μg/mL) and transplanted into four patients with type 1 diabetes. MRI studies (T2*) were performed prior to and at various time points after transplantation. Viability and in vitro and in vivo functions of labeled islets were similar to those of control islets. All patients could stop insulin after transplantation. The first patient had diffuse hypointense images on her baseline liver MRI, typical for spontaneous high iron content, and transplant‐related modifications could not be observed. The other three patients had normal intensity on pretransplant images, and iron‐loaded islets could be identified after transplantation as hypointense spots within the liver. In one of them, i.v. iron therapy prevented subsequent visualization of the spots because of diffuse hypointense liver background. Altogether, this study demonstrates the feasibility and safety of MRI‐based islet graft monitoring in clinical practice. Iron overload (spontaneous or induced) represents the major obstacle to the technique.

FLIP switches Fas-mediated glucose signaling in human pancreatic β cells from apoptosis to cell replication

Type 2 diabetes mellitus results from an inadequate adaptation of the functional pancreatic β cell mass in the face of insulin resistance. Changes in the concentration of glucose play an essential role in the regulation of β cell turnover. In human islets, elevated glucose concentrations impair β cell proliferation and induce β 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 β 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 β cells; FLIP was no longer detectable in such TUNEL-positive β cells. Up-regulation of FLIP, by incubation with transforming growth factor β or by transfection with an expression vector coding for FLIP, protected β cells from glucose-induced apoptosis, restored β cell proliferation, and improved β 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 β cell and suggest a novel approach to prevent and treat diabetes by switching Fas signaling from apoptosis to proliferation.

Human islet transplantation network for the treatment of Type I diabetes: first data from the Swiss-French GRAGIL consortium (1999–2000)

Aims/hypothesis. Improvements in islet transplantation require clinical series large enough to implement controlled new strategies. The goal of this study was to demonstrate the feasibility of a multicentre network for islet transplantation in Type I (insulin-dependent) diabetic patients. Methods. The five centres (Besançon, Geneva, Grenoble, Lyon, Strasbourg) of the GRAGIL network allow pancreas procurement, recipient recruitment, transplantation procedure and follow-up. Islet isolation is, however, performed in one single laboratory (Geneva). Pancreata were procured in each of the five centres and transported to Geneva with an ischaemia time of less than 8 hours. Islets were isolated using a standard automated method. If the islet number was too low for a graft ( < 6000 Islet-equivalent /kg), islets were cultured up to 12 days until another isolation was possible. Islets were transplanted by percutaneous transhepatic intraportal injection. Immunosuppression consisted of cyclosporine, mycophenolate mofetil, steroids and an anti-interleukin 2 receptor antibody. Results. From March 1999 to June 2000, 56 pancreata procurements were performed with an average yield of 234 500 islet-equivalent, with 32 preparations over 200 000 islet-equivalent. Ten C-peptide negative Type I diabetic patients (5 men and 5 women, median age 44 years, median diabetes duration 29 years) with an established kidney graft ( > 6 months) received 9030 ± 1090 islet-equivalent/kg with a median purity of 63 %. The number of pancreata required for each graft was 1 (n = 5) or 2 (n = 5). At the completion of a 12 month follow-up, we observed 0 % primary nonfunction, 50 % graft survival and 20 % insulin-independence. Conclusions/interpretation. This study demonstrates the interest and the feasibility of a multicentre collaboration in human islet transplantation. [Diabetologia (2001) 44: 859–864]

Potential impact of in situ liver splitting on the number of available grafts.

Background. 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. Methods. The records of 407 consecutive donors during a 4-year period in Switzerland were analyzed. Non-heart-beating donors and donors with missing data were excluded, leaving 338 donors as the study population. Liver splitting was considered feasible when the following criteria were met: age≥14 and ≤50 years; weight≥45 kg; body mass index≤26 kg/m2; intensive care stay≤3 days; mean arterial pressure≥60 mm Hg; Na≤160 mmol/L; serum glutamic pyruvic transaminase≤60 U/L; &ggr;-glutamyl transpeptidase≤50 U/L; no steatosis at ultrasonography. Organs from donors≥70 kg were considered suitable for a split, producing organs for two adults. Results. Fifty-two (15%) donors fulfilled all the conditions for a split-liver procedure, of whom 29 (8.6%) were donors for 2 adults. The number of donors suitable for splitting increased to 145 (43%) if donors with only one missing criterion were included (77 [23%] for 2 adults). Conclusion. Even if the technique is restricted to optimal donors, splitting could appreciably increase the number of liver grafts. A wider use of the technique could reduce the patient’s time on the waiting list and the need for living-donor procedures, and should be encouraged.

NGF-withdrawal induces apoptosis in pancreatic beta cells in vitro

Abstract.Aims/hypothesis: Using primary cultures of human pancreatic islets, purified human pancreatic beta cells and the mouse βTC6-F7 cell line, we analysed the expression of nerve growth factor, (NGF/NGF) receptors in beta cells. To investigate whether NGF could sub-serve an autocrine antiapoptotic role in beta cells, we studied the effects of NGF withdrawal using a neutralizing monoclonal anti-NGF antibody. Methods: The expression of NGF and NGF receptors (gp140Trk-A and p75NTR) were analysed by RT-PCR and immunofluorescence. Pulse-chase experiments and beta cell/PC12 co-cultures were used to investigate NGF production and secretion from beta cells. Possible apoptosis induced by NGF withdrawal was monitored by phosphatidylserine translocation, nucleosomal formation, DNA laddering and FACS analysis. Involvement of transcription/translation mechanisms were investigated as well as the gp140Trk-A required. Finally, signal transduction pathways typically involved in apoptotic mechanisms were analysed by western blot analysis. Results: We show that NGF and both NGF receptors, gp140Trk-A and p75NTR are expressed in beta cells where NGF is produced and secreted in a biologically active form. NGF-withdrawal induces beta-cell transcription/translation independent apoptosis but mediated by gp140Trk-A. Analysis of signal transduction pathways revealed that NGF withdrawal inhibits the PI3-K, protein kinase B (AKT), Bad survival pathway and activates c-Jun kinase (JNK) whereas ERKs and p38 mitogen-activated protein kinase (MAPK) are not affected. Moreover, Bcl-XL, but not Bcl-2 protein expression are reduced. Conclusion/interpretaiton: We suggest that the integrity of the NGF/NGF receptor system and NGF bioavailability participate in controlling beta-cell survival in culture which represents a key issue for improving possibilities for transplantations in the treatment of diabetes. [Diabetologia (2001) 44: 1281–1295]

Transanal glove port is a safe and cost-effective alternative for transanal endoscopic microsurgery.

Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for excision of rectal tumours that avoids conventional pelvic resectional surgery along with its risks and side‐effects. Although appealing, the associated cost and complex learning curve limit TEM utilization by colorectal surgeons. Single‐port laparoscopic principles are being recognized as transferable to transanal work and hybrid techniques are in evolution. Here the clinical application of a new technique for transanal access is reported.

Surgical management of abdominal and retroperitoneal Castleman's disease

BackgroundAbdominal and retroperitoneal Castlemans disease could present either as a localized disease or as a systemic disease. Castlemans disease is a lymphoid hyperplasia related to human Herpes virus type 8, which could have an aggressive behavior, similar to that of malignant lymphoid neoplasm mainly with the systemic type, or a benign one in its localized form.MethodsThe authors report two cases of localized Castlemans disease in the retroperitoneal space and review the current and recent progress in the knowledge of this atypical disease.Cases presentationThe two patients were young healthy women presenting with a hyper vascular peri-renal mass suggestive of malignant tumor. Both have been resected in-toto. One of them had an extensive resection with nephrectomy, while the second had a kidney preserving surgery. Pathological examination revealed localized Castlemans disease and surgical margins were free of disease. Postoperative course was uneventful, and after more than 5-years of follow-up no recurrences have been observed.ConclusionLocalized Castlemans disease should be considered when facing a solid hypervascular abdominal or retroperitoneal mass. A better knowledge of this disorder and its characteristic would help surgeon to avoid unnecessarily extensive resection for this benign disorder when dealing with abdominal or retroperitoneal tumors. Surgical resection is curative for the localized form, when complete, while splenectomy could be indicated for the systemic form.

Waist Circumference and Waist/Hip Ratio Are Better Predictive Risk Factors for Mortality and Morbidity after Colorectal Surgery Than Body Mass Index and Body Surface Area

Objectives:To determine whether body fat distribution, measured by waist circumference (WC) and waist/hip ratio (WHR), is a better predictor of mortality and morbidity after colorectal surgery than body mass index (BMI) or body surface area (BSA). Background:Obesity measured by BMI is not a consistent risk factor for postoperative mortality and morbidity after abdominal surgery. Studies in metabolic and cardiovascular diseases have shown WC and WHR to be better outcome predictors than BMI. Methods:A prospective multicenter international study was conducted among patients undergoing elective colorectal surgery. The WHR, BMI, and BSA were derived from body weight, height, and waist and hip circumferences measured preoperatively. Uni- and multivariate analyses were performed to identify risk factors for postoperative outcomes. Results:A total of 1349 patients (754 men) from 38 centers in 11 countries were included. Increasing WHR significantly increased the risk of conversion [odds ratio (OR) = 15.7, relative risk (RR) = 4.1], intraoperative complications (OR = 11.0, RR = 3.2), postoperative surgical complications (OR = 7.7, RR = 2.0), medical complications (OR = 13.2, RR = 2.5), anastomotic leak (OR = 13.7, RR = 3.3), reoperations (OR = 13.3, RR = 2.9), and death (OR = 653.1, RR = 21.8). Both BMI (OR = 39.5, RR = 1.1) and BSA (OR = 4.9, RR = 3.1) were associated with an increased risk of abdominal wound complication. In multivariate analysis, the WHR predicted intraoperative complications, conversion, medical complications, and reinterventions, whereas BMI was a risk factor only for abdominal wall complications; BSA did not reach significance for any outcome. Conclusions:The WHR is predictive of adverse events after elective colorectal surgery. It should be used in routine clinical practice and in future risk-estimating systems.

Near-infrared laparoscopy for real-time intra-operative arterial and lymphatic perfusion imaging

Multimodal laparoscopic imaging systems possessing the capability for extended spectrum irradiation and visualization within a unified camera system are now available to provide enhanced intracorporeal operative anatomic and dynamic perfusion assessment and potentially augmented patient outcome. While ultraviolet‐range energies have limited penetration and hence are probably more useful for endoscopic mucosal interrogation, the near‐infrared (NIR) spectrum is of greater potential utility for the purposes of examining inducible fluorescence in abdominopelvic tissue that can be achieved by administration of specific tracer agents, either directly into the circulation (e.g. for anastomotic perfusion assessment at the time of stapling) or into the lymphatic system (e.g. for lymph basin road‐mapping and/or focussed target nodal assessment). This technology is also capable of supplementing anatomic recognition of the biliary system while implantable fibres can also be inserted intraoperatively for the purpose of safeguarding vital structures such as the oesphagus and ureters especially in difficult reoperations. It is likely that this technological capability will find a clear and common indication in colorectal specialist and general surgical departments worldwide in the near future.