-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: A relaparotomy for a pancreatic fistula (PF) after a pancreaticoduodenectomy (PD) is a formidable operation, and the appropriate treatment of anastomotic leakage is under debate. The objective of this study was to compare the outcomes of different strategies in managing the pancreatic remnant during a relaparotomy for PF after a PD. METHODS: In this retrospective study on prospectively collected data, 669 PD were performed between 2004 and 2011. The study group comprised 31 patients requiring a relaparotomy, because of delayed haemorrhage (n = 19) or sepsis (n = 12). The pancreatic stump was treated either using pancreas-preserving techniques (simple drainage or duct occlusion) or completion of a pancreatectomy (CP). In 2008, autologous islet transplantation (AIT) was introduced for endocrine tissue rescue of CP. RESULTS: The mortality rate, blood loss and transfusion requirement were similar for all techniques. Patients undergoing a CP required a further relaparotomy less frequently than patients with pancreas preservation (7% versus 59%, P < 0.01), and the intensive care unit (ICU) stay was reduced after CP (P = 0.058). PF persisted at discharge in 66% of patients after pancreas-preserving techniques. AIT was associated with CP in 7 patients, of whom one died post-operatively. Long-term graft function was maintained in four out of six surviving patients, with one insulin-independent patient at 36 months after transplantation. CONCLUSIONS: When a PF requires a relaparotomy, CP has become our favoured technique. AIT can reduce the metabolic impact of the procedure.
HPB 02/2013; · 1.60 Impact Factor
-
Lorenzo Piemonti,
Matthew J Everly,
Paola Maffi,
Marina Scavini,
Francesca Poli, Rita Nano,
Massimo Cardillo,
Raffaella Melzi,
Alessia Mercalli,
Valeria Sordi,
Vito Lampasona,
Alejandro Espadas de Arias,
Mario Scalamogna,
Emanuele Bosi,
Ezio Bonifacio,
Antonio Secchi,
Paul I Terasaki
[show abstract]
[hide abstract]
ABSTRACT: Long-term clinical outcome of islet transplantation is hampered by the rejection and recurrence of autoimmunity. Accurate monitoring may allow for early detection and treatment of these potentially compromising immune events. Islet transplant outcome was analyzed in 59 consecutive pancreatic islet recipients in whom baseline and de novo posttransplant autoantibodies (GAD antibody, insulinoma-associated protein 2 antigen, zinc transporter type 8 antigen) and donor-specific allo antibodies (DSA) were quantified. Thirty-nine recipients (66%) showed DSA or autoantibody increases (de novo expression or titer increase) after islet transplantation. Recipients who had a posttransplant antibody increase showed similar initial performance but significantly lower graft survival than patients without an increase (islet autoantibodies P < 0.001, DSA P < 0.001). Posttransplant DSA or autoantibody increases were associated with HLA-DR mismatches (P = 0.008), induction with antithymocyte globulin (P = 0.0001), and pretransplant panel reactive alloantibody >15% in either class I or class II (P = 0.024) as independent risk factors and with rapamycin as protective (P = 0.006) against antibody increases. DSA or autoantibody increases after islet transplantation are important prognostic markers, and their identification could potentially lead to improved islet cell transplant outcomes.
Diabetes 12/2012; · 8.29 Impact Factor
-
Rita Nano,
Leda Racanicchi,
Raffaella Melzi,
Alessia Mercalli,
Paola Maffi,
Valeria Sordi,
Zhidong Ling,
Marina Scavini,
Olle Korsgren,
Barbara Celona,
Antonio Secchi,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: High levels of donor-derived high-mobility group box-1 protein (HMGB1) have been associated with poor islet graft outcome in a mouse model. The aim of our work was to determine whether HMGB1 released by human islets had independent pro-inflammatory effects that influence engraftment in humans. Human islet preparations contained and released HMGB1 in different amounts, as determined by Western Blot and ELISA (median 17 pg/ml/IEQ/24h; min-max 0-211, n=74). HMGB1 release directly correlated with brain death, donor hyperamilasemia and factors related to the pancreas digestion procedure (collagenase and digestion time). HMGB1 release was significantly positively associated with the release of other cytokines/chemokines, in particular with the highly released "pro inflammatory" CXCL8/IL-8, CXCL1/GRO-α and with the IFNγ inducible chemokines CXCL10/IP-10 and CXCL9/MIG. HMGB1 release was not modulated by Toll Like Receptor-2,-3,-4,-5,-9 agonists or by exposure to IL-1β. When evaluated after islet transplantation, pre-transplant HMGB1 release was weekly associated to the activation of the coagulation cascade (evaluated as serum crosslinked fibrin products), but not with the immediate post transplant inflammatory response. Concordantly, HMGB1 did not impact short-term human islet function. Our data show that human islet HMGB1 release is a sign of "damaged" islets, although without any independent direct role in graft failure.
Cell Transplantation 10/2012; · 5.13 Impact Factor
-
Antonio Citro,
Elisa Cantarelli,
Paola Maffi, Rita Nano,
Raffaella Melzi,
Alessia Mercalli,
Erica Dugnani,
Valeria Sordi,
Paola Magistretti,
Luisa Daffonchio,
Pier Adelchi Ruffini,
Marcello Allegretti,
Antonio Secchi,
Ezio Bonifacio,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: Although long considered a promising treatment option for type 1 diabetes, pancreatic islet cell transformation has been hindered by immune system rejection of engrafted tissue. The identification of pathways that regulate post-transplant detrimental inflammatory events would improve management and outcome of transplanted patients. Here, we found that CXCR1/2 chemokine receptors and their ligands are crucial negative determinants for islet survival after transplantation. Pancreatic islets released abundant CXCR1/2 ligands (CXCL1 and CXCL8). Accordingly, intrahepatic CXCL1 and circulating CXCL1 and CXCL8 were strongly induced shortly after islet infusion. Genetic and pharmacological blockade of the CXCL1-CXCR1/2 axis in mice improved intrahepatic islet engraftment and reduced intrahepatic recruitment of polymorphonuclear leukocytes and NKT cells after islet infusion. In humans, the CXCR1/2 allosteric inhibitor reparixin improved outcome in a phase 2 randomized, open-label pilot study with a single infusion of allogeneic islets. These findings indicate that the CXCR1/2-mediated pathway is a regulator of islet damage and should be a target for intervention to improve the efficacy of transplantation.
The Journal of clinical investigation 09/2012; 122(10):3647-51. · 15.39 Impact Factor
-
Riccarda Granata,
Fabio Settanni,
Michel Julien, Rita Nano,
Gabriele Togliatto,
Antonella Trombetta,
Davide Gallo,
Lorenzo Piemonti,
Maria Felice Brizzi,
Thierry Abribat,
Aart-Jan van Der Lely,
Ezio Ghigo
[show abstract]
[hide abstract]
ABSTRACT: Des-acyl ghrelin, although devoid of binding to ghrelin receptor (GRLN), exerts many biological effects, including regulation of glucose and lipid metabolism. Indeed, des-acyl ghrelin promotes pancreatic β-cell and human islet cell survival and prevents diabetes in streptozotocin (STZ) treated rats. We investigated whether des-acyl ghrelin fragments excluding serine(3), which is essential for binding to GRLN, would display similar actions. Among the different compounds tested, des-acyl ghrelin((6-13)) and des-acyl ghrelin((6-13)) with alanine substitutions or cyclization, but not with d-amino acid substitutions, showed the best survival effect, similar to des-acyl ghrelin. Des-acyl ghrelin((6-13)) even prevented diabetes in STZ-treated rats and protected human circulating angiogenic cells from oxidative stress and senescence, similar to des-acyl ghrelin. These results suggest that not only full-length des-acyl ghrelin but also short des-acyl ghrelin fragments have clear beneficial effects on several tissues in vitro and in vivo.
Journal of Medicinal Chemistry 03/2012; 55(6):2585-96. · 4.80 Impact Factor
-
Alessandra Ferraro,
Carlo Socci,
Angela Stabilini,
Andrea Valle,
Paolo Monti,
Lorenzo Piemonti, Rita Nano,
Sven Olek,
Paola Maffi,
Marina Scavini,
Antonio Secchi,
Carlo Staudacher,
Ezio Bonifacio,
Manuela Battaglia
[show abstract]
[hide abstract]
ABSTRACT: Autoimmune diseases, including type 1 diabetes, are thought to have a Th17-cell bias and/or a T-regulatory cell (Treg) defect. Understanding whether this is a hallmark of patients with type 1 diabetes is a crucial question that is still unsolved, largely due to the difficulties of accessing tissues targeted by the disease.
We phenotypically and functionally characterized Th17 cells and Tregs residing in the pancreatic-draining lymph nodes (PLNs) of 19 patients with type 1 diabetes and 63 nondiabetic donors and those circulating in the peripheral blood of 14 type 1 diabetic patients and 11 healthy subjects.
We found upregulation of Th17 immunity and functional defects in CD4(+)CD25(bright) Tregs in the PLNs of type 1 diabetic subjects but not in their peripheral blood. In addition, the proinsulin-specific Treg-mediated control was altered in the PLNs of diabetic patients. The dysfunctional Tregs isolated from diabetic subjects did not contain contaminant effector T cells and were all epigenetically imprinted to be suppressive, as defined by analysis of the Treg-specific demethylated region within the forkhead box P3 (FOXP3) locus.
These data provide evidence for an unbalanced immune status in the PLNs of type 1 diabetic subjects, and treatments restoring the immune homeostasis in the target organ of these patients represent a potential therapeutic strategy.
Diabetes 09/2011; 60(11):2903-13. · 8.29 Impact Factor
-
Marco F Lombardo,
Fabiana De Angelis,
Luca Bova,
Barbara Bartolini,
Federico Bertuzzi, Rita Nano,
Barbara Capuani,
Renato Lauro,
Massimo Federici,
Davide Lauro,
Giulia Donadel
[show abstract]
[hide abstract]
ABSTRACT: The search for factors either promoting islets proliferation or survival during adult life is a major issue for both type 1 and 2 diabetes mellitus. Among factors with mitogenic activity on pancreatic β-cells, human placental lactogen (hPL) showed stronger activity when compared to the other lactogen hormones: growth hormone (GH) and prolactin (PRL). The aim of the present work is to elucidate the biological and molecular events of hPL isoform A (hPL-A) activity on human cultured islets. We used pure human pancreatic islets and insulinoma cell lines (βTC-1 and RIN, murine and rat respectively) stimulated with hPL-A recombinant protein and we compared hPL-A activity with that of hGH. We showed that hPL-A inhibits apoptosis, both in insulinoma and human islets, by the phosphorylation of AKT protein. Indeed, the antiapoptotic role of hPL-A was mediated by PI3K, p38 and it was independent by PKA, Erk1/2. Compared with hGH, hPL-A modulated at different intervals and/or intensity by the phosphorylation of JAKs/STATs and MAPKinases. Moreover, hPL-A induced PDX-1 intracellular expression, improving beta cell activity and ameliorating insulin secretion in response to high glucose stimulation. Our data support the idea that hPL-A is involved in the regulation of beta cells activity. Importantly, we found that hPL-A can preserve and improve the ability of purified human pancreatic islets cultured to secrete insulin in vitro.
Islets 09/2011; 3(5):250-8.
-
Andrea Caumo,
Paola Maffi, Rita Nano,
Livio Luzi,
Robert Hilbrands,
Pieter Gillard,
Daniel Jacobs-Tulleneers-Thevissen,
Antonio Secchi,
Bart Keymeulen,
Daniel Pipeleers,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: Several simple measures of graft function after islet transplantation have been proposed but a comparative evaluation is lacking. Here, we compared the performance of five indices of β-cell function: β-score, transplant estimated function (TEF), homeostasis model assessment (HOMA) 2-B%, C-peptide/glucose ratio, and Secretory Units of Islets in Transplantation (SUIT).
Two cohorts of transplanted patients were analyzed. Cohort 1 consisted of 14 recipients with type 1 diabetes of islet transplantation whereas cohort 2 consisted of 21 recipients with type 1 diabetes of cultured islet cell graft. The five surrogate indices were compared against the first- and second-phase insulin response to arginine in cohort 1, and against the C-peptide response to a hyperglycemic clamp in cohort 2.
We found that the performances of the five surrogate indices were close one to each other in cohort 1. The correlation coefficients ranged 0.62 to 0.67 and 0.62 to 0.68 against the first- and second-phase insulin response to arginine, respectively. In cohort 2, we found that the β-score, TEF, C-peptide/glucose ratio, and SUIT were reasonably well correlated with the clamp response (correlation coefficients were in the range 0.71-0.81), whereas HOMA2-B% showed a modest performance (r=0.54). HOMA2-B% could not be evaluated in one patient whose fasting glucose concentration level was below the lower bound indicated by the HOMA calculator (3 mmol/L). SUIT could not be evaluated in three patients whose fasting glucose concentration was below the glucose threshold of the SUIT formula (3.43 mmol/L).
In summary, no single index outperformed the others. Nevertheless, when the benefit to cost ratio is considered, TEF stands out for its good performance at a very low cost.
Transplantation 08/2011; 92(7):815-21. · 4.00 Impact Factor
-
Paola Maffi,
Marina Scavini,
Carlo Socci,
Lorenzo Piemonti,
Rossana Caldara,
Chiara Gremizzi,
Raffaella Melzi, Rita Nano,
Elena Orsenigo,
Massimo Venturini,
Carlo Staudacher,
Alessandro Del Maschio,
Antonio Secchi
[show abstract]
[hide abstract]
ABSTRACT: Pancreas and islet transplantation are the only available options to replace beta-cell function in patients with type 1 diabetes. Great variability in terms of rate of success for both approaches is reported in the literature and it is difficult to compare the respective risks and benefits.
The aim of this study was to analyze risks and benefits of pancreas transplantation alone (PTA) and islet transplantation alone (ITA) by making use of the long-term experience of a single center where both transplantations are performed. We focused on the risks and benefits of both procedures, with the objective of better defining indications and providing evidence to support the decision-making process. The outcomes of 33 PTA and 33 ITA were analyzed, and pancreas and islet function (i.e., insulin independence), perioperative events, and long-term adverse events were recorded.
We observed a higher rate of insulin independence in PTA (75%) versus ITA (59%), with the longer insulin independence among PTA patients receiving tacrolimus. The occurrence of adverse events was higher for PTA patients in terms of hospitalization length and frequency, re-intervention for surgical and immunological acute complications, CMV reactivation, and other infections.
In conclusion, these results support the practice of listing patients for PTA when the metabolic control and the progression of chronic complications require a rapid normalization of glucose levels, with the exception of patients with cardiovascular disease, because of the high surgical risks. ITA is indicated when replacement of beta-cell mass is needed in patients with a high surgical risk.
The Review of Diabetic Studies 01/2011; 8(1):44-50.
-
[show abstract]
[hide abstract]
ABSTRACT: In this study we examined the effect of rapamycin (RAPA), a key component of the immunosuppressive regimen in clinical islet transplantation, on islet engraftment and function in vivo.
Diabetic C57BL/6 or BALB/C recipient mice were transplanted with 350 syngeneic islets through the portal vein (PV-Tx; C57BL/6 n = 60; BALB/C n = 22) and treated with once-daily oral RAPA (1 mg/kg) or vehicle. No differences in post-transplant blood glucose concentrations and glucose tolerance were observed between RAPA- and vehicle-treated mice. The impact of RAPA on human islet engraftment was assessed in 10 patients with type 1 diabetes treated with : 0.1 mg/kg/day rapamycin before islet transplantation. Compared to non pre-treated islet transplant recipients (n = 12), RAPA pre-treated patients had increased blood RAPA concentrations (p = 0.006) and fasting C-peptide concentrations (p = 0.005) in the two weeks post-transplant. RAPA pre-treatment was associated with a reduction in chemokines CCL2 and CCL3 concentrations pre-transplant (p < 0.01), and a dampened chemokine response (p = 0.005) post-transplant. Concordantly, in vitro RAPA inhibited the secretion of CCL2 and CCL3 by monocytes.
Rapamycin does not adversely affect intrahepatic islet engraftment in the mouse, and potentially improves islet engraftment in humans by an anti-inflammatory mechanism.
Islets 11/2010; 1(1):42-9.
-
Valeria Sordi,
Raffaella Melzi,
Alessia Mercalli,
Roberta Formicola,
Claudio Doglioni,
Francesca Tiboni,
Giuliana Ferrari, Rita Nano,
Karolina Chwalek,
Eckhard Lammert,
Ezio Bonifacio,
Danielle Borg,
Lorenzo Piemonti
Stem Cells 02/2010; 28(2):386. · 7.78 Impact Factor
-
Raffaella Melzi,
Alessia Mercalli,
Valeria Sordi,
Elisa Cantarelli, Rita Nano,
Paola Maffi,
Giovanni Sitia,
Luca G Guidotti,
Antonio Secchi,
Ezio Bonifacio,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: High levels of donor-derived CCL2 have been associated with poor islet allograft outcome in patients with type 1 diabetes. The aim of our work was to determine whether CCL2 secreted by the islet has independent proinflammatory effects that influence engraftment and graft acceptance. Both in mice and humans CCL2 is significantly positively associated with other cytokines/chemokines, in particular with the highly released "proinflammatory" IL-6 and CXCL8 or CXCL1. Transplantation of CCL2-/- islets into syngenic recipients did not improve the transplant function. Transplantation of islets into CCL2-/- syngenic recipients led to a significant improvement of transplant function and partial abrogation of local hepatic inflammation. When evaluated in human islets CCL2 release was strongly related to the immediate local inflammatory response in the liver and impacted short-term human islet function dependently by the induced inflammatory response and independently by the immunosuppressive therapy. The data showed that islet CCL2 release is a sign of "inflamed" islets without having a direct role in graft failure. On the other hand, a causal effect for developing detrimental proinflammatory conditions after transplant was proved for recipient CCL2. Strategies to selectively decrease recipient, but not donor, CCL2 release may increase the success of islet transplantation.
Cell Transplantation 01/2010; 19(8):1031-46. · 5.13 Impact Factor
-
Valeria Sordi,
Raffaella Melzi,
Alessia Mercalli,
Roberta Formicola,
Claudio Doglioni,
Francesca Tiboni,
Giuliana Ferrari, Rita Nano,
Karolina Chwalek,
Eckhard Lammert,
Ezio Bonifacio,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: Adherent fibroblast-like cells have been reported to appear in cultures of human endocrine or exocrine pancreatic tissue during attempts to differentiate human β cells from pancreatic precursors. A thorough characterization of these mesenchymal cells has not yet been completed, and there are no conclusive data about their origin.We demonstrated that the human mesenchymal cells outgrowing from cultured human pancreatic endocrine or exocrine tissue are pancreatic mesenchymal stem cells (pMSC) that propagate from contaminating pMSC. The origin of pMSC is partly extrapancreatic both in humans and mice, and by using green fluorescent protein (GFP+) bone marrow transplantation in the mouse model, we were able to demonstrate that these cells derive from the CD45+ component of bone marrow. The pMSC express negligible levels of islet-specific genes both in basal conditions and after serum deprivation or exogenous growth factor exposure, and might not represent optimal candidates for generation of physiologically competent β-cells. On the other hand, when cotransplanted with a minimal pancreatic islet mass, pMSC facilitate the restoration of normoglycemia and the neovascularization of the graft. These results suggest that pMSCs could exert an indirect role of “helper” cells in tissue repair processes. STEM CELLS 2010;28:140–151
Stem Cells 12/2009; 28(1):140 - 151. · 7.78 Impact Factor
-
Valeria Sordi,
Raffaella Melzi,
Alessia Mercalli,
Roberta Formicola,
Claudio Doglioni,
Francesca Tiboni,
Giuliana Ferrari, Rita Nano,
Karolina Chwalek,
Eckhard Lammert,
Ezio Bonifacio,
Danielle Borg,
Lorenzo Piemonti
[show abstract]
[hide abstract]
ABSTRACT: Adherent fibroblast-like cells have been reported to appear in cultures of human endocrine or exocrine pancreatic tissue during attempts to differentiate human beta cells from pancreatic precursors. A thorough characterization of these mesenchymal cells has not yet been completed, and there are no conclusive data about their origin.We demonstrated that the human mesenchymal cells outgrowing from cultured human pancreatic endocrine or exocrine tissue are pancreatic mesenchymal stem cells (pMSC) that propagate from contaminating pMSC. The origin of pMSC is partly extrapancreatic both in humans and mice, and by using green fluorescent protein (GFP(+)) bone marrow transplantation in the mouse model, we were able to demonstrate that these cells derive from the CD45(+) component of bone marrow. The pMSC express negligible levels of islet-specific genes both in basal conditions and after serum deprivation or exogenous growth factor exposure, and might not represent optimal candidates for generation of physiologically competent beta-cells. On the other hand, when cotransplanted with a minimal pancreatic islet mass, pMSC facilitate the restoration of normoglycemia and the neovascularization of the graft. These results suggest that pMSCs could exert an indirect role of "helper" cells in tissue repair processes.
Stem Cells 11/2009; 28(1):140-51. · 7.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The available information concerning the characteristics and composition of collagenase batches, which are effective in the digestion of human pancreas for islet transplants, is scarce and incomplete. A large inter- and intrabatched variability in activity and efficiency of blend enzymes available for isolation has been observed. The aim of this study was to characterize enzyme blend components. Liberase batches were characterized by SDS-PAGE analyses, microelectrophoresis, and then by MALDI-TOF MS analysis. Three main bands were detected by SDS-PAGE analysis and submitted to MALDI-TOF MS analysis. Two bands were found to correspond to class I (isoform beta and another of 106 kDa) and one to class II (isoform delta) collagenase. These results represent an important step towards a complete characterization of enzymes, with the final aim of identifying key components for a standardized product.
Cell Transplantation 02/2009; 18(2):203-6. · 5.13 Impact Factor
-
Santina Bruzzone,
Nicoletta Bodrato,
Cesare Usai,
Lucrezia Guida,
Iliana Moreschi, Rita Nano,
Barbara Antonioli,
Floriana Fruscione,
Mirko Magnone,
Sonia Scarfì,
Antonio De Flora,
Elena Zocchi
[show abstract]
[hide abstract]
ABSTRACT: Abscisic acid (ABA) is a plant stress hormone recently identified as an endogenous pro-inflammatory cytokine in human granulocytes. Because paracrine signaling between pancreatic beta cells and inflammatory cells is increasingly recognized as a pathogenetic mechanism in the metabolic syndrome and type II diabetes, we investigated the effect of ABA on insulin secretion. Nanomolar ABA increases glucose-stimulated insulin secretion from RIN-m and INS-1 cells and from murine and human pancreatic islets. The signaling cascade triggered by ABA in insulin-releasing cells sequentially involves a pertussis toxin-sensitive G protein, cAMP overproduction, protein kinase A-mediated activation of the ADP-ribosyl cyclase CD38, and cyclic ADP-ribose overproduction. ABA is rapidly produced and released from human islets, RIN-m, and INS-1 cells stimulated with high glucose concentrations. In conclusion, ABA is an endogenous stimulator of insulin secretion in human and murine pancreatic beta cells. Autocrine release of ABA by glucose-stimulated pancreatic beta cells, and the paracrine production of the hormone by activated granulocytes and monocytes suggest that ABA may be involved in the physiology of insulin release as well as in its dysregulation under conditions of inflammation.
Journal of Biological Chemistry 10/2008; 283(47):32188-97. · 4.77 Impact Factor
-
The Lancet 08/2008; 372(9632):28; author reply 29-30. · 38.28 Impact Factor
-
Riccarda Granata,
Fabio Settanni,
Davide Gallo,
Letizia Trovato,
Luigi Biancone,
Vincenzo Cantaluppi, Rita Nano,
Marta Annunziata,
Pietro Campiglia,
Elisa Arnoletti,
Corrado Ghè,
Marco Volante,
Mauro Papotti,
Giampiero Muccioli,
Ezio Ghigo
[show abstract]
[hide abstract]
ABSTRACT: Obestatin is a newly discovered peptide encoded by the ghrelin gene whose biological functions are poorly understood. We investigated obestatin effect on survival of beta-cells and human pancreatic islets and the underlying signaling pathways.
beta-Cells and human islets were used to assess obestatin effect on cell proliferation, survival, apoptosis, intracellular signaling, and gene expression.
Obestatin showed specific binding on HIT-T15 and INS-1E beta-cells, bound to glucagon-like peptide-1 receptor (GLP-1R), and recognized ghrelin binding sites. Obestatin exerted proliferative, survival, and antiapoptotic effects under serum-deprived conditions and interferon-gamma/tumor necrosis factor-alpha/interleukin-1 beta treatment, particularly at pharmacological concentrations. Ghrelin receptor antagonist [D-Lys(3)]-growth hormone releasing peptide-6 and anti-ghrelin antibody prevented obestatin-induced survival in beta-cells and human islets. beta-Cells and islet cells released obestatin, and addition of anti-obestatin antibody reduced their viability. Obestatin increased beta-cell cAMP and activated extracellular signal-related kinase 1/2 (ERK1/2) and phosphatidylinositol 3-kinase (PI 3-kinase)/Akt; its antiapoptotic effect was blocked by inhibition of adenylyl cyclase/cAMP/protein kinase A (PKA), PI 3-kinase/Akt, and ERK1/2 signaling. Moreover, obestatin upregulated GLP-1R mRNA and insulin receptor substrate-2 (IRS-2) expression and phosphorylation. The GLP-1R antagonist exendin-(9-39) reduced obestatin effect on beta-cell survival. In human islets, obestatin, whose immunoreactivity colocalized with that of ghrelin, promoted cell survival and blocked cytokine-induced apoptosis through cAMP increase and involvement of adenylyl cyclase/cAMP/PKA signaling. Moreover, obestatin 1) induced PI 3-kinase/Akt, ERK1/2, and also cAMP response element-binding protein phosphorylation; 2) stimulated insulin secretion and gene expression; and 3) upregulated GLP-1R, IRS-2, pancreatic and duodenal homeobox-1, and glucokinase mRNA.
These results indicate that obestatin promotes beta-cell and human islet cell survival and stimulates the expression of main regulatory beta-cell genes, identifying a new role for this peptide within the endocrine pancreas.
Diabetes 05/2008; 57(4):967-79. · 8.29 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Early impairment of islet function and graft loss strongly limit the success of allogenic islet transplantation in insulin-dependent diabetes. Macrophages play a key role in this process thus the depletion of these cells may strongly affect islet survival. In this study, we have evaluated the effect of the depletion of macrophages in mouse allograft rejection using a new approach based on a single infusion of red blood cells loaded with the synthetic analogue of pyrophosphate clodronate. Graft survival was 19.4+/-0.89 and 20+/-2 days in the two control groups treated with physiological solution and unloaded erythrocytes, respectively; 25+/-1.9 days in the group treated with free-clodronate and 35+/-6 days in the erythrocytes-loaded group. Our results indicate clodronate selectively targeted to the macrophagic cells by a single administration of engineered erythrocytes can significantly prolong islet graft survival and open new therapeutic strategies in islet transplantation.
Transplantation 03/2008; 85(4):648-50. · 4.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The beta-score is a highly regarded approach to the assessment of transplant functionality. Our aim was to develop an index of beta-cell function that hinges on the pillars of the beta-score (daily insulin requirement and A1C), has a straightforward physiological interpretation, and does not require the execution of an insulin stimulation test.
The new index is denoted transplant estimated function (TEF) and is obtained from the daily insulin requirement and A1C. TEF estimates the amount of insulin secreted daily and can be normalized to the number of transplanted islets, thus permitting evaluation of the cost-effectiveness of the transplant. TEF was compared with the area under the curve of C-peptide [AUC(C-pep)] concentration over 24 h, as well as the acute insulin response to intravenous glucose (AIR(glu)) and to arginine (AIR(arg)). The association between TEF and beta-score was also investigated.
The correlation of TEF with 24-h AUC(C-pep) was r = 0.73 (P < 0.005), whereas that for beta-score versus 24-h AUC(C-pep) was r = 0.33 (NS). The correlation of TEF with AIR(glu) was r = 0.59 (P < 0.001) and close to that for beta-score versus AIR(glu) (r = 0.65, P < 0.001). The correlation of TEF with AIR(arg) was r = 0.33 (P < 0.005) and was similar to that for beta-score versus AIR(arg) (r = 0.34, P < 0.005). TEF and beta-score were correlated well (r = 0.69, P < 0.0001) and showed similar time profiles.
TEF estimates daily insulin secretion, it is simpler than the beta-score, and its performance against reference indexes of beta-cell secretion is in line with that exhibited by beta-score. TEF can be normalized to the number of transplanted islets and thereby provides a benchmarking tool to evaluate the cost-effectiveness of the transplant.
Diabetes care 02/2008; 31(2):301-5. · 8.09 Impact Factor
