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Gastroparesis is characterized by a constellation of upper gastrointestinal (GI) symptoms in association with delayed gastric emptying (GE) in the absence of mechanical outlet obstruction from the stomach. Cardinal symptoms [...]

OBJECTIVE--Identification of arterial genes and pathways altered in obesity and diabetes. RESEARCH DESIGN AND METHODS--Aortic gene expression profiles of obese and diabetic db/db, high-fat diet-fed C57BL/6J, and control mice were [...]

OBJECTIVE--There is evidence that monocytes of patients with type 1 diabetes show proinflammatory activation and disturbed migration/adhesion, but the evidence is inconsistent. Our hypothesis is that monocytes are distinctly activated/disturbed [...]

Islets are composed mostly of [beta]-cells, and therefore stem cell research has concentrated on generating purified [beta]-cells, neglecting the other endocrine cell types in the islet. We investigated the presence [...]

Melanin concentrating hormone (MCH) is a hypothalamic neuropeptide known to play a critical role in energy balance. We have previously reported that overexpression of MCH is associated with mild obesity. In addition, mice have substantial hyperinsulinemia and islet hyperplasia that is out of proportion with their degree of obesity. In this study, we further explored the role of MCH in the endocrine pancreas. Both MCH and MCHR1 are expressed in mouse and human islets and in clonal β-cell lines as assessed using quantitative real-time PCR and immunohistochemistry. Mice lacking MCH (MCH-KO) on either a C57B1/6 or 129Sv genetic background showed a significant reduction in β-cell mass and complemented our earlier observation of increased β-cell mass in MCH-overexpressing mice. Furthermore, the compensatory islet hyperplasia secondary to a high-fat diet, which was evident in wild-type controls, was attenuated in MCH-KO. Interestingly, MCH enhanced insulin secretion in human and mouse islets and rodent β-cell lines in a dose-dependent manner. Real-time PCR analyses of islet RNA derived from MCH-KO revealed altered expression of islet-enriched genes such as glucagon, forkhead homeobox A2, hepatocyte nuclear factor (HNF)4α, and HNF1α. Together, these data provide novel evidence for an autocrine role for MCH in the regulation of β-cell mass dynamics and in islet secretory function and suggest that MCH is part of a hypothalamic-islet (pancreatic) axis., Several neuropeptides that act in the central nervous system to regulate feeding behavior and energy homeostasis are also expressed in the enteric system as part of a potential hypothalamic-pancreatic axis [...]

AMP-activated protein kinase (AMPK) is a heterotrimeric protein that regulates glucose transport mediated by cellular stress or pharmacological agonists such as 5-amino-imidazole-4-carboxamide 1 β-D-ribonucleoside (AICAR). AS160, a Rub GTPase-activating protein, provides a mechanism linking AMPK signaling to glucose uptake. We show that AICAR increases AMPK, acetyl-CoA carboxylase, and AS160 phosphorylation by insulin-independent mechanisms in isolated skeletal muscle. Recombinant AMPK heterotrimeric complexes (α1β1γ1 and α2β2γ1) phosphorylate AS160 in a cell-free assay. In mice deficient in AMPK signaling (α2 AMPK knockout [KO], α2 AMPK kinase dead [KD], and γ3 AMPK KO), AICAR effects on AS160 phosphorylation were severely blunted, highlighting that complexes containing α2 and γ3 are necessary for AICAR-stimulated AS160 phosphorylation in intact skeletal muscle. Contraction-mediated AS160 phosphorylation was also impaired in α2 AMPK KO and KD but not γ3 AMPK KO mice. Our results implicate AS160 as a downstream target of AMPK., The 5'AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that is ubiquitously expressed and functions as an intracellular fuel sensor activated by depletion of high-energy phospho-compounds (1). Activation of [...]

Islet cell autoantibodies are strongly associated with the development of type 1 diabetes. The appearance of autoantibodies to one or several of the autoantigens--GAD65, IA-2, or insulin--signals an autoimmune pathogenesis of [beta]-cell killing. A [beta]-cell attack may be best reflected by the emergence of autoantibodies dependent on the genotype risk factors, isotype, and subtype of the autoantibodies as well as their epitope specificity. It is speculated that progression to [beta]-cell loss and clinical onset of type 1 diabetes is reflected in a developing pattern of epitope-specific autoantibodies. Although the appearance of autoantibodies does not follow a distinct pattern, the presence of multiple autoantibodies has the highest positive predictive value for type 1 diabetes. In the absence of reliable T-cell tests, dissection of autoantibody responses in subjects of genetic risk should prove useful in identifying triggers of islet autoimmunity by examining seroconversion and maturation of the autoantibody response that may mark time to onset of type 1 diabetes. The complexity of the disease process is exemplified by multiple clinical phenotypes, including autoimmune diabetes masquerading as type 2 diabetes in youth and adults. Autoantibodies may also provide prognostic information in clinically heterogeneous patient populations when examined longitudinally., ISLET CELL AUTOANTIBODIES Autoantibodies are created by the immune system when it falls to distinguish between 'self' and 'nonself.' It is normally trained to recognize and ignore the body's own [...]

Type 2 diabetes is a heterogeneous disease characterized by insulin resistance and altered glucose and lipid metabolism in multiple organs. To understand the complex series of events that occur during the development of obesity-associated diabetes, we examined the temporal pattern of changes in insulin action and glucose metabolism in individual organs during chronic high-fat feeding in C57BL/6 mice. Insulin-stimulated cardiac glucose metabolism was significantly reduced after 1.5 weeks of high-fat feeding, and cardiac insulin resistance was associated with blunted Akt-mediated insulin signaling and GLUT4 levels. Insulin resistance in skeletal muscle, adipose tissue, and liver developed in parallel after 3 weeks of high-fat feeding. Diet-induced whole-body insulin resistance was associated with increased circulating levels of resistin and leptin but unaltered adiponectin levels. High-fat feeding caused insulin resistance in skeletal muscle that was associated with significantly elevated intramuscular fat content. In contrast, diet-induced hepatic insulin resistance developed before a marked increase in intrahepatic triglyceride levels. Cardiac function gradually declined over the course of high-fat feeding, and after 20 weeks of high-fat diet, cardiac dysfunction was associated with mild hyperglycemia, hyperleptinemia, and reduced circulating adiponectin levels. Our findings demonstrate that cardiac insulin resistance is an early adaptive event in response to obesity and develops before changes in whole-body glucose homeostasis. This suggests that obesity-associated defects in cardiac function may not be due to insulin resistance per se but may be attributable to chronic alteration in cardiac glucose and lipid metabolism and circulating adipokines., Type 2 diabetes has reached epidemic proportions, affecting >170 million people globally, and cardiovascular disease (CVD) is the leading cause of mortality in diabetes (1,2). The incidence of obesity, which [...]

Glycogen is an important component of whole-body glucose metabolism. MGSKO mice lack skeletal muscle glycogen due to disruption of the GYS1 gene, which encodes muscle glycogen synthase. MGSKO mice were 5-10% smaller than wild-type littermates with less body fat. They have more oxidative muscle fibers and, based on the activation state of AMP-activated protein kinase, more capacity to oxidize fatty acids. Blood glucose in fed and fasted MGSKO mice was comparable to wild-type littermates. Serum insulin was lower in fed but not in fasted MGSKO animals. In a glucose tolerance test, MGSKO mice disposed of glucose more effectively than wild-type animals and had a more sustained elevation of serum insulin. This result was not explained by increased conversion to serum lactate or by enhanced storage of glucose in the liver. However, glucose infusion rate in a euglycemic-hyperinsulinemic clamp was normal in MGSKO mice despite diminished muscle glucose uptake. During the clamp, MGSKO animals accumulated significantly higher levels of liver glycogen as compared with wild-type littermates. Although disruption of the GYS1 gene negatively affects muscle glucose uptake, overall glucose tolerance is actually improved, possibly because of a role for GYS1 in tissues other than muscle., After a meal, glucose is distributed into various tissues of the body where it can be utilized as an energy source or stored as glycogen (1). Glycogen is a branched [...]

Leptin inhibits insulin secretion and preproinsulin gene expression in pancreatic [beta]-cells, but signal transduction pathways and molecular mechanisms underlying this effect are poorly characterized. In this study, we analyzed leptin-mediated signal transduction and preproinsulin gene regulation at the molecular level in pancreatic 13-cells. Leptin stimulation led to janus kinase (JAK)2-dependent phosphorylation and nuclear translocation of the transcription factors signal transducer and activator of transcription (STAT)3 and STAT5b in INS-1 [beta]-cells. Leptin also induced mRNA expression of the JAK-STAT inhibitor suppressor of cytokine signaling (SOCS)3 in INS-1 [beta]-cells and human pancreatic islets in vitro and in pancreatic islets of ob/ob mice in vivo. Transcriptional activation of the rat SOCS3 promoter by leptin was observed with concomitant leptin-induced STAT3 and STAT5b DNA binding to specific promoter regions. Unexpectedly, SOCS3 inhibited both basal and STAT3/5b-dependent rat preproinsulin 1 gene promoter activity in INS-1 cells. These results suggest that SOCS3 represents a transcriptional inhibitor of preproinsulin gene expression, which is induced by leptin through JAK-STAT3/5b signaling in pancreatic J3-cells. In conclusion, although SOCS3 is believed to be a negative feedback regulator of JAK-STAT signaling, our findings suggest involvement of SOCS3 in a direct gene regulatory pathway downstream of leptin-activated JAK-STAT signaling in pancreatic [beta]-cells., The hormone leptin is the product of the obese (ob) gene, primarily produced by white adipose tissue (1) and typically circulates in proportion to body fat mass (2). Leptin acts [...]

To investigate the role of the Sry/hydroxymethylglutaryl box (Sox) transcription factors in the development of the pancreas, we determined the expression pattern of Sox factors in the developing mouse pancreas. By RT-PCR, we detected the presence of multiple Sox family members in both the developing pancreas and mature islets and then focused on two factors, Sox2 and Sox4. The expression field of Sox2, which plays a role in the maintenance of some stem cell populations, included the developing duodenum, but Sox2 was specifically excluded from the pancreatic buds. In contrast, Sox4 was detected broadly in the early pancreatic buds and eventually became restricted to the nuclei of all islet cells in the adult mouse. Mice homozygous for a null mutation of the sox4 gene showed normal pancreatic bud formation and endocrine cell differentiation up to embryonic day 12.5. Beyond that date, cultured pancreatic explants lacking sox4 failed to form normal islets. Instead, a markedly reduced number of endocrine cells were found scattered through the explant. We show here that several Sox transcription factors are expressed in the developing pancreas and in the islet, and that one of these factors, Sox4, is required for the normal development of pancreatic islets., Scattered through the exocrine pancreas, the islets of Langerhans are highly organized clusters of endocrine cells comprised of four distinct cell types: the glucagon-secreting [alpha]-cells, the insulin-secreting [beta]-cells, the somatostatin-secreting [...]

The development of islet cell transplantation as a cure for diabetes is limited by the shortage of human donor organs. Moreover, currently used grafts exhibit a marginal [beta]-cell mass with an apparently low capacity for [beta]-cell renewal and growth. Although duct-associated nonendocrine cells have often been suggested as a potential source for [beta]-cell production, recent work in mice has demonstrated the role of [beta]-cells in postnatal growth of the pancreatic [beta]-cell mass. The present study investigated whether the [beta]-cell mass can grow in implants that are virtually devoid of nonendocrine cells. Endocrine islet cells were purified from prenatal porcine pancreases (gestation >110 days) and implanted under the kidney capsule of nude mice. [beta]-Cells initially presented with signs of immaturity: small size, low insulin content, undetectable C-peptide release, and an inability to correct hyperglycemia. They exhibited a proliferative activity that was highest during posttransplant week 1 (2.6 and 5% bromodeoxyuridine [BrdU]-positive [beta]-cells 4 and 72 h posttransplant) and then decreased over 20 weeks to rates measured in the pancreas (0.2% BrdU-positive cells). [beta]-Cell proliferation in implants first compensated for [beta]-cell loss during posttransplant week 1 and then increased the [beta]-cell number fourfold between posttransplant weeks 1 and 20. Rates of [alpha]-cell proliferation were only shortly and moderately increased, which explained the shift in cellular composition of the implant ([beta]-cell 40 vs. 90% and [alpha]-cell 40 vs. 7% at the start and posttransplant week 20, respectively). [beta]-Cells progressively matured during the 20 weeks after transplantation, with a twofold increase in cell volume, a sixfold increase in cellular insulin content, plasma C-peptide levels of 1-2 ng/ml, and an ability to correct diabetes. They became structurally organized as homogenous clusters with their secretory vesicles polarized toward fenestrated capillaries. We concluded that the immature [beta]-cell phenotype provides grafts with a marked potential for [beta]-cell growth and differentiation and hence may have a potential role in curing diabetes. Cells with this phenotype can be isolated from prenatal organs; their presence in postnatal organs needs to be investigated., Islet cell transplantation has long been considered as a potential cure for diabetes (1,2). A transplantation protocol has been reported that has achieved a consistent insulin independence that has been [...]

Current methods for measuring long-term glycemia in patients with diabetes are Hb[A.sub.1c] and advanced glycation end products (AGEs), which are estimated by phenyl boronate affinity chromatography and competitive enzyme-linked immunosorbent assay, respectively. In this study, we hypothesize that the intrinsic fluorescence property of hemoglobin-AGE (Hb-AGE) may be a simple, accurate, and therefore better index for long-term glycemic status due to its highly specific nature and longer half-life. To establish this contention, in vitro and in vivo experiments were carried out. The former was performed by incubating commercially available hemoglobin with 5 and 20 mmol/l glucose and the latter through experimentally induced (streptozotocin) diabetes in an animal model (male Wistar rats) to identify the new fluorophore formed due to the nonenzymatic glycosylation of hemoglobin. An adduct exhibiting fluorescence at 308/345 nm of excitation/emission wavelengths has been identified and its time-dependent formation established. Under in vitro conditions, the first appearance of the new fluorophore was noticed only after a period of 2 months, whereas under in vivo conditions, it increased significantly after 2 months of hyperglycemia. Consistent with the observations, studies on patients with type 2 diabetes demonstrated an elevated level of this new fluorescent adduct in patients with persisting high levels of plasma glucose for >2 months. Based on the results obtained, Hb-AGE appears to be an efficient fluorescence-based biosensing molecule for the long-term monitoring of glycemic control in diabetes., Conventional diagnosis of diabetes and determination of immediate glycemic status in such patients is based on fasting plasma glucose levels or oral glucose tolerance test (1). Glycation of total serum [...]

A strategy was developed to generate expressed sequence tags (ESTs) from human pancreatic islet gene products using differential display of mRNA. Screening of over 2,000 cDNA amplification products identified 42 [...]

The simultaneous assessment of quantitative indexes of insulin secretion and action in a single individual is important when quantifying their relative role in the evolution of glucose tolerance in different [...]

Objective: To study the extent and determinants of undiagnosed diabetes mellitus (DM) in Taiwanese subjects with impaired fasting glycemia (IFG) defined by the newly proposed WHO criteria. Research Design and [...]

The reliability of the fasting criteria for diagnosing diabetes proposed by the American Diabetes Association (ADA) have recently been questioned. We conducted a retrospective analysis in order to assess the [...]

To determine whether the fasting plasma glucose (FPG) level above 7.0 mmol/L recommended by the Expert Committee is useful to diagnose diabetes mellitus in Korean adults, we examined the data [...]

This study estimated the cost-effectiveness for diabetes screening on high-risk Spanish population omitting the oral glucose tolerance test (OGTT) when: a) Hypothesis 1=Fasting Plasma Glucose (FPG) test [is greater than [...]

To determine the prevalence of diabetes and to compare the ADA criteria with the WHO criteria in elderly Korean, SWS study was performed. SWS study was population based survey of [...]

Poor reproducibility of the 75g-OGTT is a major criticism. To test whether body composition may be a factor, we studied the coefficient of intra-subject variation (CV) following replicate 75g-OGTTs in [...]

Background. In the treatment of hypertension, the appropriate blood pressure goal should be lower for patients with diabetes than for patients without diabetes. Therefore, screening for diabetes may be important [...]

In 1997 the American Diabetes Association proposed using fasting glucose alone to diagnose individuals as normal or having impaired fasting glucose or diabetes. The World Health Organization criteria, however, use [...]

The revised American Diabetes Association (ADA) diagnostic criteria for diabetes are more easily applied in a clinical setting than the World Health Organization (WHO) criteria. However, it is not clear [...]

The revised American Diabetes Association (ADA) diagnostic criteria for diabetes are more easily applied in a clinical setting than the World Health Organization (WHO) criteria. We studied whether the new [...]

We evaluated the performance of 3 screening tests: (1) the American Diabetes Association (ADA)'s risk assessment questionnaire test, (2) a random capillary blood glucose (RCBG) test recommended by the ADA [...]

We compared the new American Diabetes Association (ADA) criteria with the 1985 World Health Organization (WHO) criteria for the diagnosis of abnormal glucose tolerance in Japanese subjects. 401 Japanese subjects [...]

While many studies have assessed the impact of the 1997 ADA diagnostic criteria for diabetes mellitus in population-based cohorts, data concerning their impact within the hospital setting is limited. To [...]

Background: Screening for diabetes is recommended for all people age 45 and older. It is unknown to what extent testing for diabetes is part of routine medical care in a [...]

Fructose stimulates the release of glucokinase from its regulatory protein, enhancing the translocation of glucokinase within the hepatocyte. Small amounts of fructose improve glucose tolerance (GT) in normal humans, especially [...]

We have modified the Naserke and coworkers protein A insulin autoantibody assay such that it is performed in 96-well filtration plates. The assay is applicable to both human sera and [...]

The current recommendations for screening and diagnosis of diabetes are based on studies in which fasting plasma glucose was measured in the morning after an overnight fast of at least [...]

In light of an occurring growth of elderly people affected by type 2 diabetes and recent observations indicating that type 2 diabetes may be a disease of the innate immune [...]

Evaluation of WHO and NDDG Criteria for Impaired Glucose Tolerance Results From Two National Samples The considerable disagreement in the definition of impaired glucose tolerance (IGT) by National Diabetes Data [...]

Rapid Detection of IDDM Susceptibility With HLA-DQ Β-Alleles as Markers The allelic forms of the human leukocyte antigen (HLA)--DQ Β-chain (DQB1) have been recognized as the best markers of insulin-dependent [...]

Ptprv is a transmembrane tyrosine phosphatase expressed in embryonic stem cells, gonads, and osteoblast precursors. In bone formation, it has been characterized as a molecular marker of mesenchymal bone collar cells and shown to play a role in osteoblast differentiation. We show for the first time that Ptprv is also expressed in adipose tissue. In this tissue, Ptprv expression is restricted to cells of the stroma vascular fraction, which contain adipocyte precursors, but is not detected in differentiated adipocytes. Moreover, Ptprv expression is regulated. Indeed, both in 3T3L1 cells and mouse embryo fibroblast models of adipocyte differentiation, Ptprv expression increases when cells reach confluence and then decreases upon exposure to adipogenic conditions. However, Ptprv expression patterns do not strictly overlap with Pref-1 and ACLP, two proteins expressed in preadipocytes but not in adipocytes. In addition, Ptprv does not appear as a critical player in adipocyte differentiation, since MEF cells lacking Ptprv are able to differentiate into adipocytes and mice lacking Ptprv have normal adipose tissue development. It is thus likely that this phosphatase does not play an important role in adipose tissue biology. Moreover, we have cloned the human ortholog of Ptprv and shown that this gene 1) has no 'functional' parent in the human genome, 2) has retained an 'intron-exon' structure, and 3) is transcribed in a regulated manner. Taken together, these results indicate that Ptprv is the only PTP-ase whose function has been lost during the evolution process between rodents and humans., From the CNRS UMR 6543 Institute of Signaling Developmental Biology and Cancer, Faculte des Sciences, Pare Valrose, Nice, France. Address correspondence to Pascal Peraldi. E-mail: [...]

Typically, insulin release assays are the gold standard to determine the ability of isolated animal and human islets to respond to glucose concentrations with adequate insulin secretion. In vitro insulin release is measured using static and dynamic incubation techniques. The ability of islet grafts to correct hyperglycemia in streptozotocin-induced diabetic immunodeficient mouse recipients also provides solid information on insulin secretion, but it involves additional engraftment factors. Overall, these procedures are time-consuming. New alternative methodologies are now available to gain information on the secretory ability of isolated human islets. Adenoviral delivery of green fluorescent protein and timer protein in the C-peptide coding region of the insulin gene allows effective expression of fluorescent pro-insulin in the granules of rodent and human islet [beta]-cells. Incubation of human islets expressing ins-C-GFP and ins-C-Timer inserts, with high glucose or exposure to cytokines, induces differences in color and fluorescence intensity between treated and untreated control islets, easily appreciated by real-time microscopic analysis. The results correlate with data accrued using more classic methodologies. This new technical approach helps to better explore the activity of insulin release in isolated human islets and may contribute to identifying markers associated with islet functionality and relevant to islet performance after transplantation., Rita Bottino, (1) A.N. Balamurugan, (1,2) Xuehui Geng, (3) Peter Drain, (3) Suzanne Bertera, (1) Massimo Trucco (1) From the (1) Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania; [...]

The cytokines interleukin (IL)-I and interferon (IFN)-[gamma] are believed to be mediators of immune-mediated [beta]-cell destruction in type 1 diabetes. Inhibition of the nuclear factor (NF)-[kappa]B and mitogen-activated protein kinase (MAPK) pathways protects [beta]-cells against cytokine-induced apoptosis, partly because of inhibition of inducible nitric oxide synthase expression and nitric oxide (NO) generation. We have previously shown that suppressor of cytokine signaling (SOCS)-3 prevents cytokine-induced NO production and apoptosis in a [beta]-cell line. The aim of this study was to investigate by microarray the gene pattern induced by IL-1 and its suppression by SOCS-3 in a [beta]-cell line. Furthermore, we also investigated whether SOCS-3 inhibits the NF-[kappa]B and MAPK pathways, NO production, and apoptosis induction in primary rat [beta]-cells. By microarray analysis (Affymetrix U34A Array), we found that IL-1 stimulation (150 pg/ml, 6 h) upregulated 23 annotated genes, 15 of which were inhibited by SOCS-3. Interestingly, of these 15 genes, 9 have previously been reported to be NF-[kappa]B dependent. Using an adenovirus expression approach, we found by Western blotting that SOCS-3 inhibited I[kappa]B degradation and MAPK activation in dispersed rat islets cultures exposed to IL-1 (250 pg/ml, 15 min). In addition, both NO production and apoptosis induction by IL-1 + IFN-[gamma] (250 and 10 ng/ml, 24 h) were suppressed 50% by SOCS-3. In conclusion, we show that expression of SOCS-3 inhibits NF-[kappa]B-dependent gene transcription in a [beta]-cell line and inhibits I[kappa]B degradation and MAPK activation in primary rat [beta]-cells. These findings elucidate the signaling pathways involved in the mechanism by which SOCS-3 reduces cytokine-induced toxicity in [beta]-cells., Peter E. Heding, (1) Sif Groth Ronn, (1) Mogens Kruhoffer, (2) Torben Falck Orntoft, (2) Helle Frobose, (1) Allan Ertman Karlsen, (1) Jorn Nerup, (1) Thomas Mandrup-Poulsen, (1) Nils Billestrup [...]