Valproic Acid Limits Pancreatic Recovery after Pancreatitis by Inhibiting Histone Deacetylases and Preventing Acinar Redifferentiation Programs.

The mechanisms by which drugs induce pancreatitis are unknown. A definite cause of pancreatitis is due to the antiepileptic drug valproic acid (VPA). On the basis of three crucial observations-that VPA inhibits histone deacetylases (HDACs), HDACs mediate pancreas development, and aspects of pancreas development are recapitulated during recovery of the pancreas after injury-we hypothesized that VPA does not cause injury on its own, but it predisposes patients to pancreatitis by inhibiting HDACs and provoking an imbalance in pancreatic recovery. In an experimental model of pancreatic injury, we found that VPA delayed recovery of the pancreas and reduced acinar cell proliferation. In addition, pancreatic expression of class I HDACs (which are the primary VPA targets) increased in the midphase of pancreatic recovery. VPA administration inhibited pancreatic HDAC activity and led to the persistence of acinar-to-ductal metaplastic complexes, with prolonged Sox9 expression and sustained ß-catenin nuclear activation, findings that characterize a delay in regenerative reprogramming. These effects were not observed with valpromide, an analog of VPA that lacks HDAC inhibition. This is the first report, to our knowledge, that VPA shifts the balance toward pancreatic injury and pancreatitis through HDAC inhibition. The work also identifies a new paradigm for therapies that could exploit epigenetic reprogramming to enhance pancreatic recovery and disorders of pancreatic injury.

Activated macrophages create lineage-specific microenvironments for pancreatic acinar- and ß-cell regeneration in mice.

BACKGROUND & AIMS: Although the cells that contribute to pancreatic regeneration have been widely studied, little is known about the mediators of this process. During tissue regeneration, infiltrating macrophages debride the site of injury and coordinate the repair response. We investigated the role of macrophages in pancreatic regeneration in mice. METHODS: We used a saporin-conjugated antibody against CD11b to reduce the number of macrophages in mice following diphtheria toxin receptor-mediated cell ablation of pancreatic cells, and evaluated the effects on pancreatic regeneration. We analyzed expression patterns of infiltrating macrophages after cell-specific injury or from the pancreas of nonobese diabetic mice. We developed an in vitro culture system to study the ability of macrophages to induce cell-specific regeneration. RESULTS: Depletion of macrophages impaired pancreatic regeneration. Macrophage polarization, as assessed by expression of tumor necrosis factor-α, interleukin 6, interleukin 10, and CD206, depended on the type of injury. The signals provided by polarized macrophages promoted lineage-specific generation of acinar or endocrine cells. Macrophage from nonobese diabetic mice failed to provide signals necessary for ß-cell generation. CONCLUSIONS: Macrophages produce cell type-specific signals required for pancreatic regeneration in mice. Additional study of these processes and signals might lead to new approaches for treating type 1 diabetes or pancreatitis.

Specific transduction and labeling of pancreatic ducts by targeted recombinant viral infusion into mouse pancreatic ducts.

Specific labeling of pancreatic ducts has proven to be quite difficult. Such labeling has been highly sought after because of the power it would confer to studies of pancreatic ductal carcinogenesis, as well as studies of the source of new insulin-producing ß-cells. Cre-loxp recombination could, in theory, lineage-tag pancreatic ducts, but results have been conflicting, mainly due to low labeling efficiencies. Here, we achieved a high pancreatic duct labeling efficiency using a recombinant adeno-associated virus (rAAV) with a duct-specific sox9 promoter infused into the mouse common biliary/pancreatic duct. We saw rapid, diffuse duct-specific labeling, with 50 and 89% labeling in the pancreatic tail and head region, respectively. This highly specific labeling of ducts should greatly enhance our ability to study the role of pancreatic ducts in numerous aspects of pancreatic growth, development and function.

Duct cells contribute to regeneration of endocrine and acinar cells following pancreatic damage in adult mice.

BACKGROUND & AIMS: There have been conflicting results on a cell of origin in pancreatic regeneration. These discrepancies predominantly stem from lack of specific markers for the pancreatic precursors/stem cells, as well as differences in the targeted cells and severity of tissue injury in the experimental models so far proposed. We attempted to create a model that used diphtheria toxin receptor (DTR) to ablate specific cell populations, control the extent of injury, and avoid induction of the inflammatory response. METHODS: To target specific types of pancreatic cells, we crossed R26DTR or R26DTR/lacZ mice with transgenic mice that express the Cre recombinase in the pancreas, under control of the Pdx1 (global pancreatic) or elastase (acinar-specific) promoters. RESULTS: Exposure of PdxCre;R26DTR mice to diphtheria toxin resulted in extensive ablation of acinar and endocrine tissues but not ductal cells. Surviving cells within the ductal compartment contributed to regeneration of endocrine and acinar cells via recapitulation of the embryonic pancreatic developmental program. However, following selective ablation of acinar tissue in ElaCreERT2;R26DTR mice, regeneration likely occurred by reprogramming of ductal cells to acinar lineage. CONCLUSIONS: In the pancreas of adult mice, epithelial cells within the ductal compartment contribute to regeneration of endocrine and acinar cells. The severity of injury determines the regenerative mechanisms and cell types that contribute to this process.

Conversion of α-Cells to ß-Cells in the Postpartum Mouse Pancreas Involves Lgr5 Progeny.

In contrast to the skin and the gut, where somatic stem cells and their niche are well characterized, a definitive pancreatic multipotent cell population in the adult pancreas has yet to be revealed. Of particular interest is whether such cells may be endogenous in patients with diabetes, and if so, can they be used for therapeutic purposes? In the current study, we used two separate reporter lines to target Cre-recombinase expression to the Lgr5- or glucagon-expressing cells in the pancreas. We provide evidence for the existence of a population of cells within and in the proximity of the ducts that transiently express the stem-cell marker Lgr5 during late gestational stages. Careful timing of tamoxifen treatment in Lgr5EGFP-IRES-CreERT2 ;R26 Tomato mice allowed us to show that these Lgr5-expressing progenitor cells can differentiate into α-cells during pregnancy. Furthermore, we report on a spontaneous lineage conversion of α- to ß-cells specifically after parturition. The contribution of Lgr5 progeny to the ß-cell compartment through an α-cell intermediate phase early after pregnancy appears to be part of a novel mechanism that would counterbalance against excessive ß-cell mass reduction during ß-cell involution.

Prolactin Promotes Fibrosis and Pancreatic Cancer Progression.

Pancreatic ductal adenocarcinoma (PDAC) is associated with significant fibrosis. Recent findings have highlighted the profibrotic activity of tissue-resident macrophages in the pancreatic cancer microenvironment. Here, we show that neoplastic pancreatic epithelium, as well as a subset of tissue-resident macrophages, expresses the prolactin-receptor (PRLR). High mobility group box 1-induced prolactin expression in the pancreas maintained FAK1 and STAT3 phosphorylation within the epithelium and stroma. Gain-of-function and loss-of-function experiments demonstrated the essential role of prolactin in promoting collagen deposition and fibrosis. Finally, the signaling cascade downstream of prolactin/PRLR activated STAT3 rather than STAT5 in PDAC. These findings suggest that targeting prolactin together with IL6, a known major activator of STAT3, could represent a novel therapeutic strategy for treating pancreatic cancer. SIGNIFICANCE: Prolactin is a key factor in the cross-talk between the stroma and neoplastic epithelium, functioning to promote fibrosis and PDAC progression.

The evaluation of metabolic parameters and insulin sensitivity for a more robust diagnosis of the polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is considered predominantly as a hyperandrogenetic syndrome and the evaluation of metabolic parameters and insulin sensitivity is not mandatory. CONTEXT: PCOS diagnostic criteria [National Institute of Health (NIH), Rotterdam Consensus (ROT), Androgen Excess Society (AES)] are unanimous recognized. We aimed to assess in women with suspected PCOS whether the application of the three diagnostic criteria differently characterizes the metabolic profile and insulin sensitivity. DESIGN: Retrospective study in a cohort of women admitted to our Outpatient Clinic for suspected PCOS. PATIENTS: Two hundred and four women with suspected PCOS in comparison to a group of normal, age-matched Sicilian women (N = 34) without signs of metabolic syndrome. MEASUREMENTS: We evaluated hyperandrogenaemia and clinical hyperandrogenism, ovarian morphology, hypothalamo-hypophyseal axis and metabolic syndrome parameters. An oral glucose tolerance test (OGTT; 75 g glucose) measured areas under the curve (AUC) for insulin, C peptide and homeostasis model assessment of insulin-resistance (HOMA-IR) were performed. RESULTS: The prevalence of PCOS was 51% according to NIH, 83% to ROT and 70.6% to AES, and only 100 patients were qualified simultaneously under these three criteria. The prevalence of the metabolic syndrome in PCOS women was 26.92% (NIH), 21.77% (ROT) and 23.61% (AES), respectively. In comparison to healthy women, PCOS women showed increased fasting insulinaemia (PCOS/ROT: P = 0.028; PCOS/NIH: P = 0.007; PCOS/EAS: P = 0.023), 120 min insulin after OGTT insulinaemia (for the three criteria: P < 0.001), AUC(2h) insulin (for the three criteria: P < 0.001) and AUC(2h) C peptide (for the three criteria: P < 0.001). CONCLUSIONS: Our study highlights the fact that regardless of the diagnostic criteria used, evaluation of the metabolic parameters and insulin sensitivity is important for a correct diagnosis of PCOS and a therapeutic approach.

Use of glargine in pregnant women with type 1 diabetes mellitus: a case-control study.

BACKGROUND: Insulin glargine is a once-daily basal insulin analog with prolonged duration of action and absence of an evident peak. Glargine is associated with reduced frequency of hypoglycemic episodes (mostly nocturnal) as well as effective glycemic control. Maintenance of good metabolic control before conception and throughout pregnancy is essential to lower the risk of fetal malformations. Glargine might be a valuable alternative in the management of pregnancies complicated by diabetes mellitus. However, because its clinical utility has not been established, the use of glargine is not currently recommended during pregnancy. OBJECTIVE: The aim of this study was to retrospectively evaluate (years 2004-2007) the effectiveness and safety of insulin glargine compared with neutral protamine Hagedorn (NPH) in women affected by type 1 diabetes mellitus (T1DM) during pregnancy. METHODS: The study comprised pregnant women affected by T1DM who were followed up in the Diabetes and Pregnancy Outpatient Clinic at the University of Palermo, Palermo, Italy, within 8 +/- 3.4 weeks subsequent to a positive pregnancy test. All patients with T1DM were treated with conventional basal-bolus insulin therapy (aspart or lispro analogs at the 3 main meals plus glargine or NPH at bedtime). Healthy pregnant women were used as controls for fetal and neonatal parameters. Patients were consecutively enrolled. In all women, metabolic status was determined daily by mean glycemic values (2-hour postprandial blood glucose) and glycosylated hemoglobin (HbA1c) values (at 3-month intervals). Fetal measurements (<50th and >90th centiles of the head circumference, abdomen circumference, and femoral length) were evaluated by ultrasound at second and third trimesters. Weight and femoral length were assessed at birth, and neonates were classified according to the fetal growth curve for the Italian population (<10th centile = small for gestational age; and >90th centile = large for gestational age (LGA). RESULTS: A total of 73 pregnant women (30 with T1DM and 43 healthy [control]) were included in the study. Of the 30 diabetic pregnant women included in the study, 15 (mean [SD] age, 27.4 [5.2] years; mean pregravidic weight, 59.7 [11.7] kg) maintained their preconception therapy with glargine, and 15 (mean age, 30.1 [2.4] years; mean pregravidic weight, 60.7 [8.7] kg) with NPH. No significant difference was observed between the glargine-treated group and the NPH-treated group with regard to pregravidic hypertension, third-trimester preeclampsia, maternal complications and/or their progression during pregnancy (diabetic retinopathy, micro- or macroalbuminuria) and episodes of mild hypoglycemia, severe hypoglycemia, and ketosis. There were no significant between group differences in insulin requirements (IU/kg of body weight) and glycemic profile, with the exception of better fasting and 2 hours after breakfast glycemic values in the glargine group during the first (P = 0.008 and P < 0.001, respectively) and the second (P = 0.015 and P = 0.016) trimesters, confirmed by the lower HbA1c levels in the first trimester (P = 0.037). The frequency of femoral length <50th centile at both second and third trimesters was 4/15 (26.7%) in the glargine-treated group (P = 0.033 and P = 0.013, respectively, vs control), 3/15 (20.0%) and 1/15 (6.7%), respectively, in the NPH-treated group (both, P = NS vs control), and 2/43 (4.7%) and 1/43 (2.3%), respectively, in the control group. The prevalence of LGA was 7/15 (46.7%) in the glargine group (P < 0.001 vs control), 4/15 (27.6%) in the NPH group (P = 0.033 vs control), and 2/43 (4.7%) in the control group. CONCLUSIONS: Although our retrospective study involved only a small number of participants, no significant difference was found in glycemic control between glargine and NPH treatments. Use of glargine was associated with a significantly higher frequency of femoral length <50th centile. Further larger prospective studies are necessary to assess the safety profile of glargine in T1DM during pregnancy.

Identification of Newly Committed Pancreatic Cells in the Adult Mouse Pancreas.

Multipotent epithelial cells with high Aldehyde dehydrogenase activity have been previously reported to exist in the adult pancreas. However, whether they represent true progenitor cells remains controversial. In this study, we isolated and characterized cells with ALDH activity in the adult mouse or human pancreas during physiological conditions or injury. We found that cells with ALDH activity are abundant in the mouse pancreas during early postnatal growth, pregnancy, and in mouse models of pancreatitis and type 1 diabetes (T1D). Importantly, a similar population of cells is found abundantly in healthy children, or in patients with pancreatitis or T1D. We further demonstrate that cells with ALDH activity can commit to either endocrine or acinar lineages, and can be divided into four sub-populations based on CD90 and Ecadherin expression. Finally, our in vitro and in vivo studies show that the progeny of ALDH1+/CD90-/Ecad- cells residing in the adult mouse pancreas have the ability to initiate Pancreatic and duodenal homeobox (Pdx1) expression for the first time. In summary, we provide evidence for the existence of a sortable population of multipotent non-epithelial cells in the adult pancreas that can commit to the pancreatic lineage following proliferation and mesenchymal to epithelial transition (MET).

Lower insulin sensitivity differentiates hirsute from non-hirsute Sicilian women with polycystic ovary syndrome.

OBJECTIVE: It is well known that hyperandrogenism and insulin-resistance with or without compensatory hyperinsulinism are closely associated, but the Rotterdam Consensus has concluded that principally obese women with polycystic ovary syndrome (PCOS) should be evaluated for the metabolic syndrome. Our aim was to study insulin sensitivity in PCOS women with hirsutism regardless of obesity. METHODS: Clinical characteristics, sex hormones and fasting- and after OGTT-glycemia and insulinemia, homeostatic model of insulin resistance (HOMA IR), and Matsuda index of insulin sensitivity were analyzed in 130 women with PCOS. Hirsutism has been evaluated through the Ferriman-Gallwey (FG) map scoring system. RESULTS: PCOS women with hirsutism (57.7% of participants) showed significant higher values of total testosterone levels (P = 0.016), free testosterone (P = 0.027), DHEA sulfate (P = 0.017), and Delta4androstenedione (P = 0.018). They had similar body mass index (BMI) (P = 0.073) and were significantly less insulin sensitive (P = 0.002) than those without hirsutism (42.3% of participants). In women with PCOS and hirsutism, there was a significant correlation between FG score and insulin-sensitivity indexes (HOMA IR, rho = 0.33, P = 0.005; Matsuda index, rho = -0.34, P = 0.003) but not with the androgen levels. Moreover, women with hirsutism showed a significantly greater insulin (P = 0.019), C-peptide (P = 0.002), and glucose (P = 0.024) areas under the curve (auc2h). CONCLUSIONS: Our study suggests that the increased responsiveness of the pilo-sebaceous unit to androgens seems to be influenced by insulin sensitivity and that insulin resistance should be assessed in all hirsute women with PCOS regardless of their BMI, as insulin resistance was found in hirsute women irrespective of whether they were overweight or obese.

Multiple pluripotent stem cell markers in human anaplastic thyroid cancer: the putative upstream role of SOX2.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is a rare and aggressive endocrine tumor with highly undifferentiated morphology. It has been suggested that cancer stem cells (CSCs) might play a central role in ATC. The objectives of this study were (i) to characterize CSCs from ex vivo ATC specimens by investigating the expression of several pluripotent stem cell markers, and (ii) to evaluate in vitro drug resistance modifications after specific CSC transcription factor switch-off. METHODS: In ex vivo experiments, eight formalin-fixed, paraffin-embedded ATC specimens were analyzed by reverse-transcription and real-time quantitative PCR and immunohistochemistry. In in vitro experiments using ATC SW1736 cells, the expression levels of OCT-4, NANOG, and ABCG2 and the sensitivity to either cisplatin or doxorubicin were evaluated after silencing. RESULTS: OCT-4, KLF4, and SOX2 transcription factors and C-KIT and THY-1 stem surface antigens showed variable up-regulation in all ATC cases. The SW1736 cell line was characterized by a high percentage of stem population (10.4±2.1% of cells were aldehyde dehydrogenase positive) and high expression of several CSC markers (SOX2, OCT4, NANOG, C-MYC, and SSEA4). SOX2 silencing down-regulated OCT-4, NANOG, and ABCG2. SOX2 silencing sensitized SW1736 cells, causing a significant cell death increase (1.8-fold) in comparison to control cells with 10 µM cisplatin (93.9±3.4% vs. 52.6±9.4%, p<0.01) and 2.7 fold with 0.5 µM doxorubicin (45.8±9.9% vs. 17.1±3.4% p<0.01). ABCG2 silencing caused increased cell death with both cisplatin (74.9±1.4%) and doxorubicin treatment (74.1±0.1%) vs. no-target-treated cells (respectively, 45.8±1.0% and 48.6±1.0%, p<0.001). CONCLUSIONS: The characterization of CSCs in ATC through the analysis of multiple pluripotent stem cell markers might be useful in identifying cells with a stem-like phenotype capable of resisting conventional chemotherapy. In addition, our data demonstrate that SOX2 switch-off through ABCG2 transporter down-regulation has a major role in overcoming CSC chemotherapy resistance.

PanIN-specific regulation of Wnt signaling by HIF2α during early pancreatic tumorigenesis.

Hypoxia promotes angiogenesis, proliferation, invasion, and metastasis of pancreatic cancer. Essentially, all studies of the hypoxia pathway in pancreatic cancer research to date have focused on fully malignant tumors or cancer cell lines, but the potential role of hypoxia inducible factors (HIF) in the progression of premalignant lesions has not been critically examined. Here, we show that HIF2α is expressed early in pancreatic lesions both in human and in a mouse model of pancreatic cancer. HIF2α is a potent oncogenic stimulus, but its role in Kras-induced pancreatic neoplasia has not been discerned. We used the Ptf1aCre transgene to activate Kras(G12D) and delete Hif2α solely within the pancreas. Surprisingly, loss of Hif2α in this model led to markedly higher, rather than reduced, number of low-grade pancreatic intraepithelial neoplasia (mPanIN) lesions. These lesions, however, failed to progress to high-grade mPanINs, and displayed exclusive loss of ß-catenin and SMAD4. The relationship among HIF2α, ß-catenin, and Smad4 was further confirmed in vitro, where silencing of Hif2α resulted in reduced ß-catenin and Smad4 transcript levels. Thus, with oncogenic Ras expressed in the pancreas, HIF2α modulates Wnt-signaling during mPanIN progression by maintaining appropriate levels of both Smad4 and ß-catenin.

Induction of mouse pancreatic ductal differentiation, an in vitro assay.

Despite recent technical advances for studying lineage tracing and gene functions, our knowledge of pancreatic duct progenitor cells and mechanisms involved in their differentiation remains a huge void in our understanding of pancreatic development. A deeper insight into ductal differentiation is needed because ductal cells may harbor pancreatic stem/progenitor cells that could give rise to new islets. Also, since the most common pancreatic tumors form structures expressing ductal cell-specific markers, studies of ductal development may provide better markers for pancreatic tumor classification. One major longstanding problem in the study of pancreatic ductal differentiation has been the lack of an effective in vitro model. We thus wished to develop an in vitro system for the study of pancreatic duct development. In doing so, we have developed a specific culture condition to promote ductal differentiation of E11.5 pancreatic rudiments. Normally, pancreatic explants cultured in vitro develop to form endocrine, acinar, as well as ductal cells. Here, we report that addition of a combination of EGF, fibroblast growth factor-10, and platelet-derived growth factor-AA to the explant cultures promotes ductal differentiation, while preventing endocrine and acinar differentiation. This culture system for differentiation and enrichment of pancreatic ductal cells may allow identification of gene(s) involved in ductal development.

In vitro generation of pancreatic endocrine cells from human adult fibroblast-like limbal stem cells.

Stem cells might provide unlimited supply of transplantable cells for ß-cell replacement therapy in diabetes. The human limbus is a highly specialized region hosting a well-recognized population of epithelial stem cells, which sustain the continuous renewal of the cornea, and the recently identified stromal fibroblast-like stem cells (f-LSCs), with apparent broader plasticity. However, the lack of specific molecular markers for the identification of the multipotent limbal subpopulation has so far limited the investigation of their differentiation potential. In this study we show that the human limbus contains uncommitted cells that could be potentially harnessed for the treatment of diabetes. Fourteen limbal biopsies were obtained from patients undergoing surgery for ocular diseases not involving the conjunctiva or corneal surface. We identified a subpopulation of f-LSCs characterized by robust proliferative capacity, expressing several pluripotent stem cell markers and exhibiting self-renewal ability. We then demonstrated the potential of f-LSCs to differentiate in vitro into functional insulin-secreting cells by developing a four-step differentiation protocol that efficiently directed f-LSCs towards the pancreatic endocrine cell fate. The expression of specific endodermal, pancreatic, islet, and ß-cell markers, as well as functional properties of f-LSC-derived insulin-producing cells, were evaluated during differentiation. With our stage-specific approach, up to 77% of f-LSCs eventually differentiated into cells expressing insulin (also assessed as C-peptide) and exhibited phenotypic features of mature ß-cells, such as expression of critical transcription factors and presence of secretory granules. Although insulin content was about 160-fold lower than what observed in adult islets, differentiated cells processed ∼98% of their proinsulin content, similar to mature ß-cells. Moreover, they responded in vitro in a regulated manner to multiple secretory stimuli, including glucose. In conclusion, f-LSCs represent a possible relevant source of autologous, transplantable, insulin-producing cells that could be tested for the reversal of diabetes.

In vitro phenotypic, genomic and proteomic characterization of a cytokine-resistant murine ß-TC3 cell line.

Type 1 diabetes mellitus (T1DM) is caused by the selective destruction of insulin-producing ß-cells. This process is mediated by cells of the immune system through release of nitric oxide, free radicals and pro-inflammatory cytokines, which induce a complex network of intracellular signalling cascades, eventually affecting the expression of genes involved in ß-cell survival.The aim of our study was to investigate possible mechanisms of resistance to cytokine-induced ß-cell death. To this purpose, we created a cytokine-resistant ß-cell line (ß-TC3R) by chronically treating the ß-TC3 murine insulinoma cell line with IL-1ß + IFN-γ. ß-TC3R cells exhibited higher proliferation rate and resistance to cytokine-mediated cell death in comparison to the parental line. Interestingly, they maintained expression of ß-cell specific markers, such as PDX1, NKX6.1, GLUT2 and insulin. The analysis of the secretory function showed that ß-TC3R cells have impaired glucose-induced c-peptide release, which however was only moderately reduced after incubation with KCl and tolbutamide. Gene expression analysis showed that ß-TC3R cells were characterized by downregulation of IL-1ß and IFN-γ receptors and upregulation of SOCS3, the classical negative regulator of cytokines signaling. Comparative proteomic analysis showed specific upregulation of 35 proteins, mainly involved in cell death, stress response and folding. Among them, SUMO4, a negative feedback regulator in NF-kB and JAK/STAT signaling pathways, resulted hyper-expressed. Silencing of SUMO4 was able to restore sensitivity to cytokine-induced cell death in ß-TC3R cells, suggesting it may play a key role in acquired cytokine resistance by blocking JAK/STAT and NF-kB lethal signaling.In conclusion, our study represents the first extensive proteomic characterization of a murine cytokine-resistant ß-cell line, which might represent a useful tool for studying the mechanisms involved in resistance to cytokine-mediated ß-cell death. This knowledge may be of potential benefit for patients with T1DM. In particular, SUMO4 could be used as a therapeutical target.

Predictors of microvascular complications in type 1 diabetic patients at onset: the role of metabolic memory.

BACKGROUND: Several epidemiological studies showed a close association between metabolic control and microvascular complications in type 1 Diabetes Mellitus (T1DM). The aim of our longitudinal observational study was to evaluate the predictive role of the main clinical and biochemical parameters in determining microvascular complications. METHODS: 376 T1DM patients, hospitalized in our division from 1991 to 2005 (mean follow-up=10.93±4.26 years) were studied. Stepwise Cox regression analysis was used to identify the influence of residual ß-cell function, ß-cell autoimmunity, HbA1c levels and other clinical and laboratory parameters in the development of microalbuminuria and retinopathy. RESULTS: The probability of developing microalbuminuria was higher in males than in females (HR 1.82; 95% CI 1.01-3.28; p=0.044), in patients with higher mean HbA1c values (HR 2.80; 95% CI 1.63-4.83; p<0.001), longer duration of disease (HR 1.98; 95% CI 1.10-3.57; p=0.022) and younger age of diabetes onset (HR 0.53; 95% CI 0.03-0.92; p=0.026). An increased probability of developing retinopathy was found in patients with higher mean HbA1c levels during follow-up (HR 2.35; 95% CI 1.34-4.12, p=0.003), as well as at onset (HR 1.85; 95% CI 1.06-3.24; p=0.030). CONCLUSIONS: Our study suggests that among the clinical, metabolic, immunological and biochemical factors evaluated at onset, only HbA1c is predictive for the microangiopathy development in T1DM.

BRAFV600E mutation, TIMP-1 upregulation, and NF-κB activation: closing the loop on the papillary thyroid cancer trilogy.

BRAF(V600E) is the most common mutation found in papillary thyroid carcinoma (PTC). Tissue inhibitor of metalloproteinases (TIMP-1) and nuclear factor (NF)-κB have been shown to play an important role in thyroid cancer. In particular, TIMP-1 binds its receptor CD63 on cell surface membrane and activates Akt signaling pathway, which is eventually responsible for its anti-apoptotic activity. The aim of our study was to evaluate whether interplay among these three factors exists and exerts a functional role in PTCs. To this purpose, 56 PTC specimens were analyzed for BRAF(V600E) mutation, TIMP-1 expression, and NF-κB activation. We found that BRAF(V600E) mutation occurs selectively in PTC nodules and is associated with hyperactivation of NF-κB and upregulation of both TIMP-1 and its receptor CD63. To assess the functional relationship among these factors, we first silenced BRAF gene in BCPAP cells, harboring BRAF(V600E) mutation. We found that silencing causes a marked decrease in TIMP-1 expression and NF-κB binding activity, as well as decreased invasiveness. After treatment with specific inhibitors of MAPK pathway, we found that only sorafenib was able to increase IκB-α and reduce both TIMP-1 expression and Akt phosphorylation in BCPAP cells, indicating that BRAF(V600E) activates NF-κB and this pathway is MEK-independent. Taken together, our findings demonstrate that BRAF(V600E) causes upregulation of TIMP-1 via NF-κB. TIMP-1 binds then its surface receptor CD63, leading eventually to Akt activation, which in turn confers antiapoptotic behavior and promotion of cell invasion. The recognition of this functional trilogy provides insight on how BRAF(V600E) determines cancer initiation, progression, and invasiveness in PTC, also identifying new therapeutic targets for the treatment of highly aggressive forms.

Visceral Adiposity Index: a reliable indicator of visceral fat function associated with cardiometabolic risk.

OBJECTIVE: To individuate a novel sex-specific index, based on waist circumference, BMI, triglycerides, and HDL cholesterol, indirectly expressing visceral fat function. RESEARCH DESIGN AND METHODS: Visceral adiposity index (VAI) was first modeled on 315 nonobese healthy subjects. Using two multiple logistic regression models, VAI was retrospectively validated in 1,498 primary care patients in comparison to classical cardio- and cerebrovascular risk factors. RESULTS: All components of metabolic syndrome increased significantly across VAI quintiles. VAI was independently associated with both cardiovascular (odd ratio [OR] 2.45; 95% CI 1.52-3.95; P < 0.001) and cerebrovascular (1.63; 1.06-2.50; P = 0.025) events. VAI also showed significant inverse correlation with insulin sensitivity during euglycemic-hyperinsulinemic clamp in a subgroup of patients (R(s) = -0.721; P < 0.001). By contrast, no correlations were found for waist circumference and BMI. CONCLUSIONS: Our study suggests VAI is a valuable indicator of "visceral adipose function" and insulin sensitivity, and its increase is strongly associated with cardiometabolic risk.

Recovery of endogenous beta-cell function in nonhuman primates after chemical diabetes induction and islet transplantation.

OBJECTIVE: To describe the ability of nonhuman primate endocrine pancreata to reestablish endogenous insulin production after chemical beta-cell destruction. RESEARCH DESIGN AND METHODS: Eleven monkeys (Macaca fascicularis) were rendered diabetic with streptozotocin. Eight diabetic monkeys received intraportal porcine islet transplantation. RESULTS: Two monkeys transplanted after 75 days of type 1 diabetes showed recovery of endogenous C-peptide production a few weeks after transplantation, concomitant with graft failure. Histological analysis of the pancreas of these monkeys showed insulin-positive cells, single or in small aggregates, scattered in the pancreas and adjacent to ducts. Interestingly, numerous CK19(+) cells costained with proinsulin and PDX-1 antibodies. Furthermore, the peculiar double phenotype glucagon-positive/GLUT2(+) was observed. In these monkeys as well as in all others, the original islets showed no insulin staining. CONCLUSIONS: Our data provide evidence that, in nonhuman primates, the pancreas can reestablish endogenous insulin production after chemical beta-cell destruction. This seems to be a nongeneralizable event with only 2 out of 11 monkeys recovering beta-cell function. In these two monkeys, younger age and islet graft behavior might have played a role in triggering endogenous beta-cell recovery.

In vitro identification and characterization of CD133(pos) cancer stem-like cells in anaplastic thyroid carcinoma cell lines.

BACKGROUND: Recent publications suggest that neoplastic initiation and growth are dependent on a small subset of cells, termed cancer stem cells (CSCs). Anaplastic Thyroid Carcinoma (ATC) is a very aggressive solid tumor with poor prognosis, characterized by high dedifferentiation. The existence of CSCs might account for the heterogeneity of ATC lesions. CD133 has been identified as a stem cell marker for normal and cancerous tissues, although its biological function remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: ATC cell lines ARO, KAT-4, KAT-18 and FRO were analyzed for CD133 expression. Flow cytometry showed CD133(pos) cells only in ARO and KAT-4 (64+/-9% and 57+/-12%, respectively). These data were confirmed by qRT-PCR and immunocytochemistry. ARO and KAT-4 were also positive for fetal marker oncofetal fibronectin and negative for thyrocyte-specific differentiating markers thyroglobulin, thyroperoxidase and sodium/iodide symporter. Sorted ARO/CD133(pos) cells exhibited higher proliferation, self-renewal, colony-forming ability in comparison with ARO/CD133(neg). Furthermore, ARO/CD133(pos) showed levels of thyroid transcription factor TTF-1 similar to the fetal thyroid cell line TAD-2, while the expression in ARO/CD133(neg) was negligible. The expression of the stem cell marker OCT-4 detected by RT-PCR and flow cytometry was markedly higher in ARO/CD133(pos) in comparison to ARO/CD133(neg) cells. The stem cell markers c-KIT and THY-1 were negative. Sensitivity to chemotherapy agents was investigated, showing remarkable resistance to chemotherapy-induced apoptosis in ARO/CD133(pos) when compared with ARO/CD133(neg) cells. CONCLUSIONS/SIGNIFICANCE: We describe CD133(pos) cells in ATC cell lines. ARO/CD133(pos) cells exhibit stem cell-like features--such as high proliferation, self-renewal ability, expression of OCT-4--and are characterized by higher resistance to chemotherapy. The simultaneous positivity for thyroid specific factor TTF-1 and onfFN suggest they might represent putative thyroid cancer stem-like cells. Our in vitro findings might provide new insights for novel therapeutic approaches.