Erica Dugnani

CXCR1/2 inhibition enhances pancreatic islet survival after transplantation

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.

Rapamycin unbalances the polarization of human macrophages to M1

Plasticity is a hallmark of macrophages, and in response to environmental signals these cells undergo different forms of polarized activation, the extremes of which are called classic (M1) and alternative (M2). Rapamycin (RAPA) is crucial for survival and functions of myeloid phagocytes, but its effects on macrophage polarization are not yet studied. To address this issue, human macrophages obtained from six normal blood donors were polarized to M1 or M2 in vitro by lipopolysaccharide plus interferon‐γ or interleukin‐4 (IL‐4), respectively. The presence of RAPA (10 ng/ml) induced macrophage apoptosis in M2 but not in M1. Beyond the impact on survival in M2, RAPA reduced CXCR4, CD206 and CD209 expression and stem cell growth factor‐β, CCL18 and CCL13 release. In contrast, in M1 RAPA increased CD86 and CCR7 expression and IL‐6, tumour necrosis factor‐α and IL‐1β release but reduced CD206 and CD209 expression and IL‐10, vascular endothelial growth factor and CCL18 release. In view of the in vitro data, we examined the in vivo effect of RAPA monotherapy (0·1 mg/kg/day) in 12 patients who were treated for at least 1 month before islet transplant. Cytokine release by Toll‐like receptor 4‐stimulated peripheral blood mononuclear cells showed a clear shift to an M1‐like profile. Moreover, macrophage polarization 21 days after treatment showed a significant quantitative shift to M1. These results suggest a role of mammalian target of rapamycin (mTOR) into the molecular mechanisms of macrophage polarization and propose new therapeutic strategies for human M2‐related diseases through mTOR inhibitor treatment.

(Ir)relevance of Metformin Treatment in Patients with Metastatic Pancreatic Cancer: An Open-Label, Randomized Phase II Trial

Purpose: We aimed to assess the safety and efficacy of metformin for treating patients with metastatic pancreatic cancer and to identify endocrine and metabolic phenotypic features or tumor molecular markers associated with sensitivity to metformin antineoplastic action. Experimental Design: We designed an open-label, randomized, phase II trial to assess the efficacy of adding metformin to a standard systemic therapy with cisplatin, epirubicin, capecitabine, and gemcitabine (PEXG) in patients with metastatic pancreatic cancer. Patients ages 18 years or older with metastatic pancreatic cancer were randomly assigned (1:1) to receive PEXG every 4 weeks in combination or not with 2 g oral metformin daily. The primary endpoint was 6-months progression-free survival (PFS-6) in the intention-to-treat population. Results: Between August 2010 and January 2014, we randomly assigned 60 patients to receive PEXG with (n = 31) or without metformin (n = 29). At the preplanned interim analysis, the study was ended for futility. PFS-6 was 52% [95% confidence interval (CI), 33–69] in the control group and 42% (95% CI, 24–59) in the metformin group (P = 0.61). Furthermore, there was no difference in disease-free survival and overall survival between groups. Despite endocrine metabolic modifications induced by metformin, there was no correlation with the outcome. Single-nucleotide polymorphism rs11212617 predicted glycemic response, but not tumor response to metformin. Gene expression on tumor tissue did not predict tumor response to metformin. Conclusions: Addition of metformin at the dose commonly used in diabetes did not improve outcome in patients with metastatic pancreatic cancer treated with standard systemic therapy. Clin Cancer Res; 22(5); 1076–85. ©2015 AACR. See related commentary by Yang and Rustgi, p. 1031

β-Cell Differentiation of Human Pancreatic Duct–Derived Cells After In Vitro Expansion

β-Cell replacement therapy is a promising field of research that is currently evaluating new sources of cells for clinical use. Pancreatic epithelial cells are potent candidates for β-cell engineering, but their large-scale expansion has not been evidenced yet. Here we describe the efficient expansion and β-cell differentiation of purified human pancreatic duct cells (DCs). When cultured in endothelial growth-promoting media, purified CA19-9(+) cells proliferated extensively and achieved up to 22 population doublings over nine passages. While proliferating, human pancreatic duct-derived cells (HDDCs) downregulated most DC markers, but they retained low CK19 and SOX9 gene expression. HDDCs acquired mesenchymal features but differed from fibroblasts or pancreatic stromal cells. Coexpression of duct and mesenchymal markers suggested that HDDCs were derived from DCs via a partial epithelial-to-mesenchymal transition (EMT). This was supported by the blockade of HDDC appearance in CA19-9(+) cell cultures after incubation with the EMT inhibitor A83-01. After a differentiation protocol mimicking pancreatic development, HDDC populations contained about 2% of immature insulin-producing cells and showed glucose-unresponsive insulin secretion. Downregulation of the mesenchymal phenotype improved β-cell gene expression profile of differentiated HDDCs without affecting insulin protein expression and secretion. We show that pancreatic ducts represent a new source for engineering large amounts of β-like-cells with potential for treating diabetes.

Transplant Site Influences the Immune Response After Islet Transplantation: Bone Marrow vs Liver.

Background The aim of this study was to characterize the immune response against intrabone marrow (BM-Tx) or intraliver (liver-Tx) transplanted islets in the presence or in the absence of immunosuppression. Methods Less (C57BL/6 in Balb/c) and highly (Balb/c in C57BL/6) stringent major histocompatibility complex fully mismatched mouse models were used to evaluate the alloimmune response. Single antigen-mismatched mouse model (C57BL/6 RIP-GP in C57BL/6) was used to evaluate the antigen-specific immune response. Mice received tacrolimus (FK-506, 0.1 mg/kg per day)/mycophenolate mofetil (MMF, 60 mg/kg per day), and anti-CD3 (50 &mgr;g/day) either alone or in combination. Results Transplant site did not impact the timing nor the kinetics of the alloimmune and single antigen-specific memory T cell responses in the absence of immunosuppression or in the presence of MMF/FK-506 combination. On the other hand, the median time to graft rejection was 28 ± 5.2 days and 16 ± 2.6 days (P = 0.14) in the presence of anti-CD3 treatment, 50 ± 12.5 days and 10 ± 1.3 days (P = 0.003) in the presence of anti-CD3/MMF/FK-506 treatment for liver-Tx and BM-Tx, respectively. Anti-CD3 did not differentially reach BM and liver tissues but was more effective in reducing graft associated T cell responses in liver-Tx than in BM-Tx. Conclusions Islets infused in the BM appear less protected from the adaptive immune response in the presence of the anti-CD3 treatment. This result raises some concerns over the potential of the BM as a site for islet allotransplantation.

Diabetes After Pancreatic Surgery: Novel Issues

In the developed world, pancreatic surgery is becoming more common, with an increasing number of patients developing diabetes because of either partial or total pancreatectomy, with a significant impact on quality of life and survival. Although these patients are expected to consume increasing health care resources in the near future, many aspects of diabetes after pancreatectomy are still not well defined. The treatment of diabetes in these patients takes advantage of the therapies used in type 1 and 2 diabetes; however, no specific guidelines for its management, both immediately after pancreatic surgery or in the long term, have been developed. In this article, on the basis of both the literature and our clinical experience, we address the open issues and discuss the most appropriate therapeutic options for patients with diabetes after pancreatectomy.

Establishment, characterization and long-term culture of human endocrine pancreas-derived microvascular endothelial cells.

BACKGROUND In vitro primary cultures of microvascular endothelial cells from endocrine pancreas are difficult to obtain, but can be a very helpful tool for studies of islet biology, transplantation and regenerative medicine. METHODS We applied a protocol recently described for the isolation and culture of brain microvascular endothelial cells (EC) on human pancreatic islets. EC obtained were characterized in terms of morphological (light and transmission electron microscopy), phenotypical (by immunofluorescence and flow cytometry) and functional (cord formation assay and protein secretion by multiplex bead-based assay) characteristics. RESULTS EC were obtained from 25% of islet preparations processed. Two primary endothelial cell lines showed high proliferative potential and were deeply characterized: they presented endothelial cell morphology and expressed CD31, CD49a, CD49e, CD34, von Willebrand Factor (vWF), Vascular Endothelial CAdherin (VE-CAD), Tyrosine Kinase with Ig and EGF Homology Domains-2 (TIE2), Vascular Endothelial Growth Factor Receptor 1 (VEGFR1), Ulex lectin and the endothelium endocrine-specific marker nephrin. Besides, they were able to form cordons in vitro and secreted factors involved in the process of angiogenesis such as Vascular Endothelial Growth Factor (VEGF), Monocyte Chemotactic Protein 1 (MCP-1), interleukin (IL)-8 and Melanoma Growth Stimulatory Activity Alpha (GROα). These cell lines were termed Human Islet Microvascular Endothelial Cells (HIMEC). DISCUSSION This study establishes a simple and effective strategy for isolation and long-term culture of EC derived from human pancreatic islet. HIMEC in culture preserve phenotype and functional properties and are, therefore, a useful tool for future experiments of in vitro pancreas modelling, co-transplantation with pancreatic islets, re-vascularization of scaffold or matrix for regenerative medicine purposes.

Mass spectrometric analysis reveals O-methylation of pyruvate kinase from pancreatic cancer cells

AbstractPyruvate kinase (PK) is an important glycolytic enzyme that catalyzes the dephosphorylation of phosphoenolpyruvate to pyruvate. Human PK isozyme M2 (PKM2), a splice variant of M1, is overexpressed in many cancer cells, and PKM2 has been investigated as a potential tumor marker for diagnostic assays and as a target for cancer therapy. To facilitate identification and characterization of PK, we studied the enzyme from pancreatic cancer cells and normal pancreatic duct cells by electrophoresis and mass spectrometry, and identified multiple O-methylated residues from PK. These findings advance our knowledge of the biochemical properties of PK and will be important in understanding its biological function in cells. FigurePyruvate kinase (PK) is an important glycolytic enzyme that catalyzes the dephosphorylation of phosphoenolpyruvate to pyruvate. We studied the enzyme from pancreatic cancer cells and normal pancreatic duct cells by mass spectrometry, and identified multiple O-methylated residues from PK.

Diabetes associated with pancreatic ductal adenocarcinoma is just diabetes: Results of a prospective observational study in surgical patients

BACKGROUND Identification of a specific diabetes signature associated to pancreatic ductal carcinoma (PDAC) could be a key to detect asymptomatic, early stage tumors. We aim to characterize the clinical signature and the pathogenetic factors of the different types of diabetes associated with PDAC, based on the time between diabetes and cancer diagnosis. METHODS Prospective observational study on 364 PDAC patients admitted to a referral center for pancreatic disease. Hospital and/or outpatient medical records were reviewed. Blood biochemical values including fasting blood glucose, insulin and/or C-peptide, glycosylated hemoglobin and anti-islet antibodies were determined. Diabetes onset was assessed after surgery and during follow-up. RESULTS The prevalence of diabetes in patients was 67%. Considering 174 patients (47.8%) already having diabetes when diagnosed with PDAC (long duration, short duration, concomitant), the clinical and biochemical profile was similar to that of patients with type 2 diabetes (T2D). Diabetes was associated with known risk factors (i.e., age, sex, family history for diabetes and increased BMI) and both beta-cell dysfunction and insulin resistance were present. Considering 70 patients (19.2%) with onset of diabetes after PDAC diagnosis (early and late onset), the strongest predictor was the loss of beta-cell mass following pancreatectomy in patients with risk factors for T2D. CONCLUSION Different types of diabetes according to the time between diabetes and PDAC diagnosis are clinical entities widely overlapping with T2D. Therefore, the success of a strategy considering diabetes onset as a marker of asymptomatic PDAC will largely depend on our ability to identify new diabetes-unrelated biomarkers of PDAC.

Effect of Diabetes on Survival after Resection of Pancreatic Adenocarcinoma. A Prospective, Observational Study.

Aim To investigate the effect of diabetes mellitus (DM) on disease-free and overall post-resection survival of patients with pancreatic ductal adenocarcinoma (PDAC) Methods Prospective observational study on patients admitted for pancreatic disease from January 2008 to October 2012. DM was classified as recent-onset (<48 months before PDAC diagnosis), longstanding (≥48 months before PDAC) or new onset (after surgery). Results Of 296 patients, 140 had a diagnosis of DM prior to surgery (26 longstanding, 99 recent-onset, 15 with unknown duration). Median follow-up time was 5.4 ± 0.22 years. Patients with recent onset DM had poorer postoperative survival than patients without DM: disease-free survival and overall survival were 1.14±0.13 years and 1.52±0.12 years in recent onset DM, versus 1.3±0.15 years and 1.87±0.15 years in non-diabetic patients (p = 0.013 and p = 0.025, respectively). Longstanding DM and postoperative new onset DM had no impact on prognosis. Compared to cases without DM, patients with recent onset DM were more likely to have residual disease after surgery and to develop liver metastases during follow-up. Multivariate analysis confirmed recent onset DM was independently associated with PDAC relapse (hazard ratio 1.45 [1.06–1.99]). Conclusion Preoperative recent onset DM has an impact on survival after the resection of PDAC.