Comparing effects of insulin analogues and human insulin on nocturnal glycaemia in hypoglycaemia-prone people with Type 1 diabetes

DEFF Research Database (Denmark)

Kristensen, P. L.; Tarnow, L.; Bay, C.

2017-01-01

. Conclusions: Treatment with insulin analogue reduces the occurrence of nocturnal hypoglycaemia assessed by nocturnal glucose profiles in people with Type 1 diabetes prone to severe hypoglycaemia. Nocturnal glucose profiles provide a more comprehensive assessment of clinical benefit of insulin regimens......Aims: To assess the difference between analogue and human insulin with regard to nocturnal glucose profiles and risk of hypoglycaemia in people with recurrent severe hypoglycaemia. Methods: A total of 72 people [46 men, mean ± sd age 54 ± 12 years, mean ± sd HbA1c 65 ± 12 mmol/mol (8.1 ± 1.1......%), mean ± sd duration of diabetes 30 ± 14 years], who participated in a 2-year randomized, crossover trial of basal-bolus therapy with insulin detemir/insulin aspart or human NPH insulin/human regular insulin (the HypoAna trial) were studied for 2 nights during each treatment. Venous blood was drawn...

Skeletal muscle phosphatidylcholine fatty acids and insulin sensitivity in normal humans.

Science.gov (United States)

Clore, J N; Li, J; Gill, R; Gupta, S; Spencer, R; Azzam, A; Zuelzer, W; Rizzo, W B; Blackard, W G

1998-10-01

The fatty acid composition of skeletal muscle membrane phospholipids (PL) is known to influence insulin responsiveness in humans. However, the contribution of the major PL of the outer (phosphatidylcholine, PC) and inner (phosphatidylethanolamine, PE) layers of the sarcolemma to insulin sensitivity is not known. Fatty acid composition of PC and PE from biopsies of vastus lateralis from 27 normal men and women were correlated with insulin sensitivity determined by the hyperinsulinemic euglycemic clamp technique at insulin infusion rates of 0.4, 1.0, and 10.0 mU . kg-1 . min-1. Significant variation in the half-maximal insulin concentration (ED50) was observed in the normal volunteers (range 24.0-146.0 microU/ml), which correlated directly with fasting plasma insulin (r = 0.75, P insulin sensitivity was observed in PE (NS). These studies suggest that the fatty acid composition of PC may be of particular importance in the relationship between fatty acids and insulin sensitivity in normal humans.

Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells

International Nuclear Information System (INIS)

Ramasharma, K.; Li, C.H.

1987-01-01

Human granulosa cells cultured with calf serum actively proliferated for 18-20 generations and secreted progesterone into the medium; progesterone levels appeared to decline with increase in generation number. Cells cultured under serum-free conditions secreted significant amounts of progesterone and insulin-like growth factor II (IGF-II). The progesterone secretion was enhanced by the addition of human follitropin, lutropin, and chorionic gonadotropin but not by growth hormone. These cells, when challenged to varying concentrations of human growth hormone, human chorionic somatomammotropin, human prolactin, chorionic gonadotropin, follitropin, and lutropin, secreted IGF-II into the medium as measured by specific IGF-II RIA. Among these human hormones, chorionic gonadotropin, follitropin, and lutropin were most effective in inducing IGF-II secretion from these cells. When synthetic lutropin-releasing hormone and α-inhibin-92 were tested, only lutropin-releasing hormone was effective in releasing IGF-II. The results described suggest that cultured human granulosa cells can proliferate and actively secrete progesterone and IGF-II into the medium. IGF-II production in human granulosa cells was influenced by a multi-hormonal complex including human growth hormone, human chorionic somatomammotropin, and prolactin

Generation of insulin-producing human mesenchymal stem cells using recombinant adeno-associated virus.

Science.gov (United States)

Kim, Jeong Hwan; Park, Si-Nae; Suh, Hwal

2007-02-28

The purpose of current experiment is the generation of insulin-producing human mesenchymal stem cells as therapeutic source for the cure of type 1 diabetes. Type 1 diabetes is generally caused by insulin deficiency accompanied by the destruction of islet beta-cells. In various trials for the treatment of type 1 diabetes, cell-based gene therapy using stem cells is considered as one of the most useful candidate for the treatment. In this experiment, human mesenchymal stem cells were transduced with AAV which is containing furin-cleavable human preproinsulin gene to generate insulin-producing cells as surrogate beta-cells for the type 1 diabetes therapy. In the rAAV production procedure, rAAV was generated by transfection of AD293 cells. Human mesenchymal stems cells were transduced using rAAV with a various multiplicity of infection. Transduction of recombinant AAV was also tested using beta-galactosidse expression. Cell viability was determined by using MTT assay to evaluate the toxicity of the transduction procedure. Expression and production of Insulin were tested using reverse transcriptase-polymerase chain reaction and immunocytochemistry. Secretion of human insulin and C-peptide from the cells was assayed using enzyme-linked immunosorbent assay. Production of insulin and C-peptide from the test group represented a higher increase compared to the control group. In this study, we examined generation of insulin-producing cells from mesenchymal stem cells by genetic engineering for diabetes therapy. This work might be valuable to the field of tissue engineering for diabetes treatment.

Fetal and perinatal outcomes in type 1 diabetes pregnancy: a randomized study comparing insulin aspart with human insulin in 322 subjects

DEFF Research Database (Denmark)

Hod, Moshe; Damm, Peter; Kaaja, Risto

2008-01-01

The objective of the study was a comparison of insulin aspart (IAsp) with human insulin (HI) in basal-bolus therapy with neutral protamine Hagedorn for fetal and perinatal outcomes of type 1 diabetes in pregnancy.......The objective of the study was a comparison of insulin aspart (IAsp) with human insulin (HI) in basal-bolus therapy with neutral protamine Hagedorn for fetal and perinatal outcomes of type 1 diabetes in pregnancy....

Differentiation of insulin-producing cells from human neural progenitor cells.

Directory of Open Access Journals (Sweden)

Yuichi Hori

2005-04-01

Full Text Available BACKGROUND: Success in islet-transplantation-based therapies for type 1 diabetes, coupled with a worldwide shortage of transplant-ready islets, has motivated efforts to develop renewable sources of islet-replacement tissue. Islets and neurons share features, including common developmental programs, and in some species brain neurons are the principal source of systemic insulin. METHODS AND FINDINGS: Here we show that brain-derived human neural progenitor cells, exposed to a series of signals that regulate in vivo pancreatic islet development, form clusters of glucose-responsive insulin-producing cells (IPCs. During in vitro differentiation of neural progenitor cells with this novel method, genes encoding essential known in vivo regulators of pancreatic islet development were expressed. Following transplantation into immunocompromised mice, IPCs released insulin C-peptide upon glucose challenge, remained differentiated, and did not form detectable tumors. CONCLUSION: Production of IPCs solely through extracellular factor modulation in the absence of genetic manipulations may promote strategies to derive transplantable islet-replacement tissues from human neural progenitor cells and other types of multipotent human stem cells.

Celastrol Protects against Antimycin A-Induced Insulin Resistance in Human Skeletal Muscle Cells

Directory of Open Access Journals (Sweden)

Mohamad Hafizi Abu Bakar

2015-05-01

Full Text Available Mitochondrial dysfunction and inflammation are widely accepted as key hallmarks of obesity-induced skeletal muscle insulin resistance. The aim of the present study was to evaluate the functional roles of an anti-inflammatory compound, celastrol, in mitochondrial dysfunction and insulin resistance induced by antimycin A (AMA in human skeletal muscle cells. We found that celastrol treatment improved insulin-stimulated glucose uptake activity of AMA-treated cells, apparently via PI3K/Akt pathways, with significant enhancement of mitochondrial activities. Furthermore, celastrol prevented increased levels of cellular oxidative damage where the production of several pro-inflammatory cytokines in cultures cells was greatly reduced. Celastrol significantly increased protein phosphorylation of insulin signaling cascades with amplified expression of AMPK protein and attenuated NF-κB and PKC θ activation in human skeletal muscle treated with AMA. The improvement of insulin signaling pathways by celastrol was also accompanied by augmented GLUT4 protein expression. Taken together, these results suggest that celastrol may be advocated for use as a potential therapeutic molecule to protect against mitochondrial dysfunction-induced insulin resistance in human skeletal muscle cells.

Cancer risk among insulin users: comparing analogues with human insulin in the CARING five-country cohort study.

Science.gov (United States)

But, Anna; De Bruin, Marie L; Bazelier, Marloes T; Hjellvik, Vidar; Andersen, Morten; Auvinen, Anssi; Starup-Linde, Jakob; Schmidt, Marjanka K; Furu, Kari; de Vries, Frank; Karlstad, Øystein; Ekström, Nils; Haukka, Jari

2017-09-01

The aim of this work was to investigate the relationship between use of certain insulins and risk for cancer, when addressing the limitations and biases involved in previous studies. National Health Registries from Denmark (1996-2010), Finland (1996-2011), Norway (2005-2010) and Sweden (2007-2012) and the UK Clinical Practice Research Datalink database (1987-2013) were used to conduct a cohort study on new insulin users (N = 327,112). By using a common data model and semi-aggregate approach, we pooled individual-level records from five cohorts and applied Poisson regression models. For each of ten cancer sites studied, we estimated the rate ratios (RRs) by duration (≤0.5, 0.5-1, 1-2, 2-3, 3-4, 4-5, 5-6 and >6 years) of cumulative exposure to insulin glargine or insulin detemir relative to that of human insulin. A total of 21,390 cancer cases occurred during a mean follow-up of 4.6 years. No trend with cumulative treatment time for insulin glargine relative to human insulin was observed in risk for any of the ten studied cancer types. Of the 136 associations tested in the main analysis, only a few increased and decreased risks were found: among women, a higher risk was observed for colorectal (RR 1.54, 95% CI 1.06, 2.25) and endometrial cancer (RR 1.78, 95% CI 1.07, 2.94) for ≤0.5 years of treatment and for malignant melanoma for 2-3 years (RR 1.92, 95% CI 1.02, 3.61) and 4-5 years (RR 3.55, 95% CI 1.68, 7.47]); among men, a lower risk was observed for pancreatic cancer for 2-3 years (RR 0.34, 95% CI 0.17, 0.66) and for liver cancer for 3-4 years (RR 0.36, 95% CI 0.14, 0.94) and >6 years (RR 0.22, 95% CI 0.05, 0.92). Comparisons of insulin detemir with human insulin also showed no consistent differences. The present multi-country study found no evidence of consistent differences in risk for ten cancers for insulin glargine or insulin detemir use compared with human insulin, at follow-up exceeding 5 years.

Bovine and human insulin adsorption at lipid monolayers: a comparison

Science.gov (United States)

Mauri, Sergio; Pandey, Ravindra; Rzeznicka, Izabela; Lu, Hao; Bonn, Mischa; Weidner, Tobias

2015-07-01

Insulin is a widely used peptide in protein research and it is utilised as a model peptide to understand the mechanics of fibril formation, which is believed to be the cause of diseases such as Alzheimer and Creutzfeld-Jakob syndrome. Insulin has been used as a model system due to its biomedical relevance, small size and relatively simple tertiary structure. The adsorption of insu lin on a variety of surfaces has become the focus of numerous studies lately. These works have helped in elucidating the consequence of surface/protein hydrophilic/hydrophobic interaction in terms of protein refolding and aggregation. Unfortunately, such model surfaces differ significantly from physiological surfaces. Here we spectroscopically investigate the adsorption of insulin at lipid monolayers, to further our understanding of the interaction of insulin with biological surfaces. In particular we study the effect of minor mutations of insulin’s primary amino acid sequence on its interaction with 1,2-Dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) model lipid layers. We probe the structure of bovine and human insulin at the lipid/water interface using sum frequency generation spectroscopy (SFG). The SFG experiments are complemented with XPS analysis of Langmuir-Schaefer deposited lipid/insulin films. We find that bovine and human insulin, even though very similar in sequence, show a substantially different behavior when interacting with lipid films.

A role for SPARC in the moderation of human insulin secretion.

Directory of Open Access Journals (Sweden)

Lorna W Harries

Full Text Available AIMS/HYPOTHESIS: We have previously shown the implication of the multifunctional protein SPARC (Secreted protein acidic and rich in cysteine/osteonectin in insulin resistance but potential effects on beta-cell function have not been assessed. We therefore aimed to characterise the effect of SPARC on beta-cell function and features of diabetes. METHODS: We measured SPARC expression by qRT-PCR in human primary pancreatic islets, adipose tissue, liver and muscle. We then examined the relation of SPARC with glucose stimulated insulin secretion (GSIS in primary human islets and the effect of SPARC overexpression on GSIS in beta cell lines. RESULTS: SPARC was expressed at measurable levels in human islets, adipose tissue, liver and skeletal muscle, and demonstrated reduced expression in primary islets from subjects with diabetes compared with controls (p< = 0.05. SPARC levels were positively correlated with GSIS in islets from control donors (p< = 0.01. Overexpression of SPARC in cultured beta-cells resulted in a 2.4-fold increase in insulin secretion in high glucose conditions (p< = 0.01. CONCLUSIONS: Our data suggest that levels of SPARC are reduced in islets from donors with diabetes and that it has a role in insulin secretion, an effect which appears independent of SPARC's modulation of obesity-induced insulin resistance in adipose tissue.

Sequence-specific 1H-NMR assignments for the aromatic region of several biologically active, monomeric insulins including native human insulin.

Science.gov (United States)

Roy, M; Lee, R W; Kaarsholm, N C; Thøgersen, H; Brange, J; Dunn, M F

1990-06-12

The aromatic region of the 1H-FT-NMR spectrum of the biologically fully-potent, monomeric human insulin mutant, B9 Ser----Asp, B27 Thr----Glu has been investigated in D2O. At 1 to 5 mM concentrations, this mutant insulin is monomeric above pH 7.5. Coupling and amino acid classification of all aromatic signals is established via a combination of homonuclear one- and two-dimensional methods, including COSY, multiple quantum filters, selective spin decoupling and pH titrations. By comparisons with other insulin mutants and with chemically modified native insulins, all resonances in the aromatic region are given sequence-specific assignments without any reliance on the various crystal structures reported for insulin. These comparisons also give the sequence-specific assignments of most of the aromatic resonances of the mutant insulins B16 Tyr----Glu, B27 Thr----Glu and B25 Phe----Asp and the chemically modified species des-(B23-B30) insulin and monoiodo-Tyr A14 insulin. Chemical dispersion of the assigned resonances, ring current perturbations and comparisons at high pH have made possible the assignment of the aromatic resonances of human insulin, and these studies indicate that the major structural features of the human insulin monomer (including those critical to biological function) are also present in the monomeric mutant.

Serological analysis of human IgG and IgE anti-insulin antibodies by solid-phase radioimmunoassays

International Nuclear Information System (INIS)

Hamilton, R.G.; Rendell, M.; Adkinson, N.F. Jr.

1980-01-01

A single solid-phase assay system which is useful for quantitative measurement of both IgG and IgE anti-insulin antibodies in human serum has been developed. Insulin-specific immunoglobulins are absorbed from human serum by excess quantities of insulin-agarose. After washes to remove unbound immunoglobulins, radioiodinated Staph A or rabbit anti-human IgE is added to detect bound IgG or IgE anbitodies, respectively

Human blood-brain barrier insulin-like growth factor receptor

International Nuclear Information System (INIS)

Duffy, K.R.; Pardridge, W.M.; Rosenfeld, R.G.

1988-01-01

Insulin-like growth factor (IGF)-1 and IGF-2, may be important regulatory molecules in the CNS. Possible origins of IGFs in brain include either de novo synthesis or transport of circulating IGFs from blood into brain via receptor mediated transcytosis mechanisms at the brain capillary endothelial wall, ie, the blood-brain barrier (BBB). In the present studies, isolated human brain capillaries are used as an in vitro model system of the human BBB and the characteristics of IGF-1 or IGF-2 binding to this preparation were assessed. The total binding of IGF-2 at 37 degrees C exceeded 130% per mg protein and was threefold greater than the total binding for IGF-1. However, at 37 degrees C nonsaturable binding equaled total binding, suggesting that endocytosis is rate limiting at physiologic temperatures. Binding studies performed at 4 degrees C slowed endocytosis to a greater extent than membrane binding, and specific binding of either IGF-1 or IGF-2 was detectable. Scatchard plots for either peptide were linear and the molar dissociation constant of IGF-1 and IGF-2 binding was 2.1 +/- 0.4 and 1.1 +/- 0.1 nmol/L, respectively. Superphysiologic concentrations of porcine insulin inhibited the binding of both IGF-1 (ED50 = 2 micrograms/mL) and IGF-2 (ED50 = 0.5 microgram/mL). Affinity cross linking of 125 I-IGF-1, 125 I-IGF-2, and 125 I-insulin to isolated human brain capillaries was performed using disuccinimidylsuberate (DSS). These studies revealed a 141 kd binding site for both IGF-1 and IGF-2, and a 133 kd binding site for insulin

Differential interaction of Apolipoprotein-E isoforms with insulin receptors modulates brain insulin signaling in mutant human amyloid precursor protein transgenic mice.

Science.gov (United States)

Chan, Elizabeth S; Chen, Christopher; Cole, Gregory M; Wong, Boon-Seng

2015-09-08

It is unclear how human apolipoprotein E4 (ApoE4) increases the risk for Alzheimer's disease (AD). Although Aβ levels can lead to insulin signaling impairment, these experiments were done in the absence of human ApoE. To examine ApoE role, we crossed the human ApoE-targeted replacement mice with mutant human amyloid precursor protein (APP) mice. In 26 week old mice with lower Aβ levels, the expression and phosphorylation of insulin signaling proteins remained comparable among APP, ApoE3xAPP and ApoE4xAPP mouse brains. When the mice aged to 78 weeks, these proteins were markedly reduced in APP and ApoE4xAPP mouse brains. While Aβ can bind to insulin receptor, how ApoE isoforms modulate this interaction remains unknown. Here, we showed that ApoE3 had greater association with insulin receptor as compared to ApoE4, regardless of Aβ42 concentration. In contrast, ApoE4 bound more Aβ42 with increasing peptide levels. Using primary hippocampal neurons, we showed that ApoE3 and ApoE4 neurons are equally sensitive to physiological levels of insulin. However, in the presence of Aβ42, insulin failed to elicit a downstream response only in ApoE4 hippocampal neurons. Taken together, our data show that ApoE genotypes can modulate this Aβ-mediated insulin signaling impairment.

Tissue-specific methylation of human insulin gene and PCR assay for monitoring beta cell death.

Directory of Open Access Journals (Sweden)

Mohamed I Husseiny

Full Text Available The onset of metabolic dysregulation in type 1 diabetes (T1D occurs after autoimmune destruction of the majority of pancreatic insulin-producing beta cells. We previously demonstrated that the DNA encoding the insulin gene is uniquely unmethylated in these cells and then developed a methylation-specific PCR (MSP assay to identify circulating beta cell DNA in streptozotocin-treated mice prior to the rise in blood glucose. The current study extends to autoimmune non-obese diabetic (NOD mice and humans, showing in NOD mice that beta cell death occurs six weeks before the rise in blood sugar and coincides with the onset of islet infiltration by immune cells, demonstrating the utility of MSP for monitoring T1D. We previously reported unique patterns of methylation of the human insulin gene, and now extend this to other human tissues. The methylation patterns of the human insulin promoter, intron 1, exon 2, and intron 2 were determined in several normal human tissues. Similar to our previous report, the human insulin promoter was unmethylated in beta cells, but methylated in all other tissues tested. In contrast, intron 1, exon 2 and intron 2 did not exhibit any tissue-specific DNA methylation pattern. Subsequently, a human MSP assay was developed based on the methylation pattern of the insulin promoter and human islet DNA was successfully detected in circulation of T1D patients after islet transplantation therapy. Signal levels of normal controls and pre-transplant samples were shown to be similar, but increased dramatically after islet transplantation. In plasma the signal declines with time but in whole blood remains elevated for at least two weeks, indicating that association of beta cell DNA with blood cells prolongs the signal. This assay provides an effective method to monitor beta cell destruction in early T1D and in islet transplantation therapy.

Regulation of lipogenesis by glucocorticoids and insulin in human adipose tissue.

Directory of Open Access Journals (Sweden)

Laura L Gathercole

Full Text Available Patients with glucocorticoid (GC excess, Cushing's syndrome, develop a classic phenotype characterized by central obesity and insulin resistance. GCs are known to increase the release of fatty acids from adipose, by stimulating lipolysis, however, the impact of GCs on the processes that regulate lipid accumulation has not been explored. Intracellular levels of active GC are dependent upon the activity of 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1 and we have hypothesized that 11β-HSD1 activity can regulate lipid homeostasis in human adipose tissue (Chub-S7 cell line and primary cultures of human subcutaneous (sc and omental (om adipocytes. Across adipocyte differentiation, lipogenesis increased whilst β-oxidation decreased. GC treatment decreased lipogenesis but did not alter rates of β-oxidation in Chub-S7 cells, whilst insulin increased lipogenesis in all adipocyte cell models. Low dose Dexamethasone pre-treatment (5 nM of Chub-S7 cells augmented the ability of insulin to stimulate lipogenesis and there was no evidence of adipose tissue insulin resistance in primary sc cells. Both cortisol and cortisone decreased lipogenesis; selective 11β-HSD1 inhibition completely abolished cortisone-mediated repression of lipogenesis. GCs have potent actions upon lipid homeostasis and these effects are dependent upon interactions with insulin. These in vitro data suggest that manipulation of GC availability through selective 11β-HSD1 inhibition modifies lipid homeostasis in human adipocytes.

Insulin in human milk and the use of hormones in infant formulas.

Science.gov (United States)

Shamir, Raanan; Shehadeh, Naim

2013-01-01

Human milk contains a substantial number of hormones and growth factors. Studies in animal models show that some of these peptides (e.g. insulin, insulin-like growth factor 1, IGF-1, epidermal growth factors) have an effect on the small intestine after orogastric administration. Recently, two efforts were made to incorporate growth factors into infant formulas. One of these efforts included the incorporation of IGF-1, and the second is an ongoing effort to evaluate the safety and efficacy of incorporating insulin into infant formulas. The rational and current evidence for adding insulin to infant formulas (presence in human milk, effects of orally administrated insulin on gut maturation, intestinal permeability, systemic effects and preliminary encouraging results of supplementing insulin to a preterm infant formula) is detailed in this review. If the addition of insulin to preterm infant formulas indeed results in better growth and accelerated intestinal maturation, future studies will need to address the supplementation of insulin in term infants and assess the efficacy of such supplementation in enhancing gut maturation and prevention of later noncommunicable diseases such as allergy, autoimmune diseases and obesity. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Regulation of autophagy in human skeletal muscle: effects of exercise, exercise training and insulin stimulation

Science.gov (United States)

Fritzen, Andreas M.; Madsen, Agnete B.; Kleinert, Maximilian; Treebak, Jonas T.; Lundsgaard, Anne‐Marie; Jensen, Thomas E.; Richter, Erik A.; Wojtaszewski, Jørgen; Kiens, Bente

2016-01-01

Key points Regulation of autophagy in human muscle in many aspects differs from the majority of previous reports based on studies in cell systems and rodent muscle.An acute bout of exercise and insulin stimulation reduce human muscle autophagosome content.An acute bout of exercise regulates autophagy by a local contraction‐induced mechanism.Exercise training increases the capacity for formation of autophagosomes in human muscle.AMPK activation during exercise seems insufficient to regulate autophagosome content in muscle, while mTORC1 signalling via ULK1 probably mediates the autophagy‐inhibiting effect of insulin. Abstract Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one‐legged exercise, one‐legged exercise training and subsequent insulin stimulation in exercised and non‐exercised human muscle. Acute one‐legged exercise decreased (Pexercise in human muscle. The decrease in LC3‐II/LC3‐I ratio did not correlate with activation of 5′AMP activated protein kinase (AMPK) trimer complexes in human muscle. Consistently, pharmacological AMPK activation with 5‐aminoimidazole‐4‐carboxamide riboside (AICAR) in mouse muscle did not affect the LC3‐II/LC3‐I ratio. Four hours after exercise, insulin further reduced (Pexercised and non‐exercised leg in humans. This coincided with increased Ser‐757 phosphorylation of Unc51 like kinase 1 (ULK1), which is suggested as a mammalian target of rapamycin complex 1 (mTORC1) target. Accordingly, inhibition of mTOR signalling in mouse muscle prevented the ability of insulin to reduce the LC3‐II/LC3‐I ratio. In response to 3 weeks of one‐legged exercise training, the LC3‐II/LC3‐I ratio decreased (Pexercise and insulin stimulation reduce muscle autophagosome content, while exercise

Regulation of autophagy in human skeletal muscle: effects of exercise, exercise training and insulin stimulation

DEFF Research Database (Denmark)

Fritzen, Andreas Mæchel; Madsen, Agnete Louise Bjerregaard; Kleinert, Maximilian

2016-01-01

Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one-legged exercise, one-legged exer......Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one-legged exercise, one......-legged exercise training as well as in response to subsequent insulin stimulation in exercised and non-exercised human muscle. Acute one-legged exercise decreased (phuman muscle....... The decrease in LC3-II/LC3-I ratio did not correlate with activation of AMPK trimer complexes in human muscle. Consistently, pharmacological AMPK activation with AICAR in mouse muscle did not affect the LC3-II/LC3-I ratio. Four hours after exercise, insulin further reduced (p

Expression of insulin signalling components in the sensory epithelium of the human saccule

DEFF Research Database (Denmark)

Degerman, Eva; Rauch, Uwe; Lindberg, Sven

2013-01-01

signalling components in the inner ear is sparce. Our immunohistochemistry approach has shown that the insulin receptor, insulin receptor substrate 1 (IRS1), protein kinase B (PKB) and insulin-sensitive glucose transporter (GLUT4) are expressed in the sensory epithelium of the human saccule, which also...

Brain Insulin Resistance at the Crossroads of Metabolic and Cognitive Disorders in Humans.

Science.gov (United States)

Kullmann, Stephanie; Heni, Martin; Hallschmid, Manfred; Fritsche, Andreas; Preissl, Hubert; Häring, Hans-Ulrich

2016-10-01

Ever since the brain was identified as an insulin-sensitive organ, evidence has rapidly accumulated that insulin action in the brain produces multiple behavioral and metabolic effects, influencing eating behavior, peripheral metabolism, and cognition. Disturbances in brain insulin action can be observed in obesity and type 2 diabetes (T2D), as well as in aging and dementia. Decreases in insulin sensitivity of central nervous pathways, i.e., brain insulin resistance, may therefore constitute a joint pathological feature of metabolic and cognitive dysfunctions. Modern neuroimaging methods have provided new means of probing brain insulin action, revealing the influence of insulin on both global and regional brain function. In this review, we highlight recent findings on brain insulin action in humans and its impact on metabolism and cognition. Furthermore, we elaborate on the most prominent factors associated with brain insulin resistance, i.e., obesity, T2D, genes, maternal metabolism, normal aging, inflammation, and dementia, and on their roles regarding causes and consequences of brain insulin resistance. We also describe the beneficial effects of enhanced brain insulin signaling on human eating behavior and cognition and discuss potential applications in the treatment of metabolic and cognitive disorders. Copyright © 2016 the American Physiological Society.

Tissue-specific expression of transfected human insulin genes in pluripotent clonal rat insulinoma lines induced during passage in vivo

Energy Technology Data Exchange (ETDEWEB)

Madsen, O.D.; Andersen, L.C.; Michelsen, B.; Owerbach, D.; Larsson, L.I.; Lernmark, A.; Steiner, D.F. (Hagedorn Research Laboratory, Gentofte (Denmark))

1988-09-01

The pluripotent rat islet tumor cell line MSL-G2 expresses primarily glucagon or cholecystokinin and not insulin in vitro but changes phenotype completely after prolonged in vivo cultivation to yield small-sized hypoglycemic tumors composed almost entirely of insulin-producing beta cells. When a genomic DNA fragment containing the coding and upstream regulatory regions of the human insulin gene was stably transfected into MSL-G2 cells no measurable amounts of insulin or insulin mRNA were detected in vitro. However, successive transplantation of two transfected clones resulted in hypoglycemic tumors that efficiently coexpressed human and rat insulin as determined by human C-peptide-specific immunoreagents. These results demonstrate that cis-acting tissue-specific insulin gene enhancer elements are conserved between rat and human insulin genes. The authors propose that the in vivo differentiation of MSL-G2 cells and transfected subclones into insulin-producing cells reflects processes of natural beta-cell ontogeny leading to insulin gene expression.

Tissue-specific expression of transfected human insulin genes in pluripotent clonal rat insulinoma lines induced during passage in vivo

International Nuclear Information System (INIS)

Madsen, O.D.; Andersen, L.C.; Michelsen, B.; Owerbach, D.; Larsson, L.I.; Lernmark, A.; Steiner, D.F.

1988-01-01

The pluripotent rat islet tumor cell line MSL-G2 expresses primarily glucagon or cholecystokinin and not insulin in vitro but changes phenotype completely after prolonged in vivo cultivation to yield small-sized hypoglycemic tumors composed almost entirely of insulin-producing beta cells. When a genomic DNA fragment containing the coding and upstream regulatory regions of the human insulin gene was stably transfected into MSL-G2 cells no measurable amounts of insulin or insulin mRNA were detected in vitro. However, successive transplantation of two transfected clones resulted in hypoglycemic tumors that efficiently coexpressed human and rat insulin as determined by human C-peptide-specific immunoreagents. These results demonstrate that cis-acting tissue-specific insulin gene enhancer elements are conserved between rat and human insulin genes. The authors propose that the in vivo differentiation of MSL-G2 cells and transfected subclones into insulin-producing cells reflects processes of natural beta-cell ontogeny leading to insulin gene expression

Methods for quantifying adipose tissue insulin resistance in overweight/obese humans.

Science.gov (United States)

Ter Horst, K W; van Galen, K A; Gilijamse, P W; Hartstra, A V; de Groot, P F; van der Valk, F M; Ackermans, M T; Nieuwdorp, M; Romijn, J A; Serlie, M J

2017-08-01

Insulin resistance of adipose tissue is an important feature of obesity-related metabolic disease. However, assessment of lipolysis in humans requires labor-intensive and expensive methods, and there is limited validation of simplified measurement methods. We aimed to validate simplified methods for the quantification of adipose tissue insulin resistance against the assessment of insulin sensitivity of lipolysis suppression during hyperinsulinemic-euglycemic clamp studies. We assessed the insulin-mediated suppression of lipolysis by tracer-dilution of [1,1,2,3,3- 2 H 5 ]glycerol during hyperinsulinemic-euglycemic clamp studies in 125 overweight or obese adults (85 men, 40 women; age 50±11 years; body mass index 38±7 kg m -2 ). Seven indices of adipose tissue insulin resistance were validated against the reference measurement method. Low-dose insulin infusion resulted in suppression of the glycerol rate of appearance ranging from 4% (most resistant) to 85% (most sensitive), indicating a good range of adipose tissue insulin sensitivity in the study population. The reference method correlated with (1) insulin-mediated suppression of plasma glycerol concentrations (r=0.960, PInsulin Resistance (Adipo-IR) index (fasting plasma insulin-NEFA product; r=-0.526, Pinsulin-glycerol product (r=-0.467, PInsulin Resistance Index (fasting plasma insulin-basal lipolysis product; r=0.460, PInsulin Sensitivity Check Index (QUICKI)-NEFA index (r=0.621, Pinsulin resistance (area under the curve ⩾0.801, Pinsulin sensitivity (that is, the antilipolytic action of insulin) can be reliably quantified in overweight and obese humans by simplified index methods. The sensitivity and specificity of the Adipo-IR index and the fasting plasma insulin-glycerol product, combined with their simplicity and acceptable agreement, suggest that these may be most useful in clinical practice.

Treating Type 1 Diabetes Mellitus with a Rapid-Acting Analog Insulin Regimen vs. Regular Human Insulin in Germany: A Long-Term Cost-Effectiveness Evaluation.

Science.gov (United States)

Valentine, William J; Van Brunt, Kate; Boye, Kristina S; Pollock, Richard F

2018-06-01

The aim of the present study was to evaluate the cost effectiveness of rapid-acting analog insulin relative to regular human insulin in adults with type 1 diabetes mellitus in Germany. The PRIME Diabetes Model, a patient-level, discrete event simulation model, was used to project long-term clinical and cost outcomes for patients with type 1 diabetes from the perspective of a German healthcare payer. Simulated patients had a mean age of 21.5 years, duration of diabetes of 8.6 years, and baseline glycosylated hemoglobin of 7.39%. Regular human insulin and rapid-acting analog insulin regimens reduced glycosylated hemoglobin by 0.312 and 0.402%, respectively. Compared with human insulin, hypoglycemia rate ratios with rapid-acting analog insulin were 0.51 (non-severe nocturnal) and 0.80 (severe). No differences in non-severe diurnal hypoglycemia were modeled. Discount rates of 3% were applied to future costs and clinical benefits accrued over the 50-year time horizon. In the base-case analysis, rapid-acting analog insulin was associated with an improvement in quality-adjusted life expectancy of 1.01 quality-adjusted life-years per patient (12.54 vs. 11.53 quality-adjusted life-years). Rapid-acting analog insulin was also associated with an increase in direct costs of €4490, resulting in an incremental cost-effectiveness ratio of €4427 per quality-adjusted life-year gained vs. human insulin. Sensitivity analyses showed that the base case was driven predominantly by differences in hypoglycemia; abolishing these differences reduced incremental quality-adjusted life expectancy to 0.07 quality-adjusted life-years, yielding an incremental cost-effectiveness ratio of €74,622 per quality-adjusted life-year gained. Rapid-acting analog insulin is associated with beneficial outcomes in patients with type 1 diabetes and is likely to be considered cost effective in the German setting vs. regular human insulin.

Effect of exercise on insulin action in human skeletal muscle

DEFF Research Database (Denmark)

Richter, Erik; Mikines, K J; Galbo, Henrik

1989-01-01

The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization...... was performed. Increased insulin action on glucose uptake was found in the exercised compared with the rested thigh at mean plasma insulin concentrations of 23, 40, and 410 microU/ml. Furthermore, prior contractions directed glucose uptake toward glycogen synthesis and increased insulin effects on thigh O2...... consumption and at some insulin concentrations on potassium exchange. In contrast, no change in insulin effects on limb exchange of free fatty acids, glycerol, alanine or tyrosine were found after exercise. Glycogen concentration in rested vastus lateralis muscle did not increase measurably during the clamp...

Glucose metabolism in pigs expressing human genes under an insulin promoter.

Science.gov (United States)

Wijkstrom, Martin; Bottino, Rita; Iwase, Hayoto; Hara, Hidetaka; Ekser, Burcin; van der Windt, Dirk; Long, Cassandra; Toledo, Frederico G S; Phelps, Carol J; Trucco, Massimo; Cooper, David K C; Ayares, David

2015-01-01

Xenotransplantation of porcine islets can reverse diabetes in non-human primates. The remaining hurdles for clinical application include safe and effective T-cell-directed immunosuppression, but protection against the innate immune system and coagulation dysfunction may be more difficult to achieve. Islet-targeted genetic manipulation of islet-source pigs represents a powerful tool to protect against graft loss. However, whether these genetic alterations would impair islet function is unknown. On a background of α1,3-galactosyltransferase gene-knockout (GTKO)/human (h)CD46, additional genes (hCD39, human tissue factor pathway inhibitor, porcine CTLA4-Ig) were inserted in different combinations under an insulin promoter to promote expression in islets (confirmed by immunofluorescence). Seven pigs were tested for baseline and glucose/arginine-challenged levels of glucose, insulin, C-peptide, and glucagon. This preliminary study did not show definite evidence of β-cell deficiencies, even when three transgenes were expressed under the insulin promoter. Of seven animals, all were normoglycemic at fasting, and five of seven had normal glucose disposal rates after challenge. All animals exhibited insulin, C-peptide, and glucagon responses to both glucose and arginine challenge; however, significant interindividual variation was observed. Multiple islet-targeted transgenic expression was not associated with an overtly detrimental effect on islet function, suggesting that complex genetic constructs designed for islet protection warrants further testing in islet xenotransplantation models. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Human skeletal muscle perilipin 2 and 3 expression varies with insulin sensitivity

DEFF Research Database (Denmark)

Vigelsø Hansen, Andreas; Prats Gavalda, Clara; Ploug, Thorkil

2013-01-01

Background: Impaired insulin sensitivity may partly arise from a dysregulated lipid metabolism in human skeletal muscle. This study investigates the expression levels of perilipin 2, 3, and 5, and four key lipases in human skeletal muscle from the subjects that exhibit a range from normal to very...

Fibroblast growth factor 21 improves insulin sensitivity and synergizes with insulin in human adipose stem cell-derived (hASC adipocytes.

Directory of Open Access Journals (Sweden)

Darwin V Lee

Full Text Available Fibroblast growth factor 21 (FGF21 has evolved as a major metabolic regulator, the pharmacological administration of which causes weight loss, insulin sensitivity and glucose control in rodents and humans. To understand the molecular mechanisms by which FGF21 exerts its metabolic effects, we developed a human in vitro model of adipocytes to examine crosstalk between FGF21 and insulin signaling. Human adipose stem cell-derived (hASC adipocytes were acutely treated with FGF21 alone, insulin alone, or in combination. Insulin signaling under these conditions was assessed by measuring tyrosine phosphorylation of insulin receptor (InsR, insulin receptor substrate-1 (IRS-1, and serine 473 phosphorylation of Akt, followed by a functional assay using 14C-2-deoxyglucose [14C]-2DG to measure glucose uptake in these cells. FGF21 alone caused a modest increase of glucose uptake, but treatment with FGF21 in combination with insulin had a synergistic effect on glucose uptake in these cells. The presence of FGF21 also effectively lowered the insulin concentration required to achieve the same level of glucose uptake compared to the absence of FGF21 by 10-fold. This acute effect of FGF21 on insulin signaling was not due to IR, IGF-1R, or IRS-1 activation. Moreover, we observed a substantial increase in basal S473-Akt phosphorylation by FGF21 alone, in contrast to the minimal shift in basal glucose uptake. Taken together, our data demonstrate that acute co-treatment of hASC-adipocytes with FGF21 and insulin can result in a synergistic improvement in glucose uptake. These effects were shown to occur at or downstream of Akt, or separate from the canonical insulin signaling pathway.

Heterogeneity of human plasma insulin: techniques for separating immunoreactive components and their determination by radioimmunoassay

International Nuclear Information System (INIS)

Souza, Iracelia Torres de Toledo e

1977-01-01

When human plasma is filtered on Sephadex G-SO fine, insulin immunoreactivity is recovered in two peaks: 'big insulin', the higher molecular weight component and 'little insulin', the lower molecular component, having elution volumes that correspond to those of porcine proinsulin 125 I and porcine insulin 125 I respectively. The presence of another form of immunoreactive insulin 'big big insulin' was detected from an insuloma suspect and its elution pattern corresponding to serum albumin. The eluates correspondent to 'big' and 'little' insulin as well as 'big big' component were assayed by radioimmunoassay using crystalline human insulin as a standard, porcine insulin 125 tracer and anti insulin serum. The antibody, raised in guinea-pigs, was sensitive and potent being adequate for the assay. The reactivity of insulin and proinsulin was tested against the antibody. The relative proportions of several components of total immunoreactive insulin in plasma were studied in basal conditions in five normal subjects and in the patient JSC with pancreatic insulin-secreting tumor as well as after glucose stimuli in all tolbutamide in JSC. (author)

Structure, antihyperglycemic activity and cellular actions of a novel diglycated human insulin

DEFF Research Database (Denmark)

O'Harte, F P; Boyd, A C; McKillop, A M

2000-01-01

Human insulin was glycated under hyperglycemic reducing conditions and a novel diglycated form (M(r) 6135.1 Da) was purified by RP-HPLC. Endoproteinase Glu-C digestion combined with mass spectrometry and automated Edman degradation localized glycation to Gly(1) and Phe(1) of the insulin A- and B-...

Trends in the use and cost of human and analogue insulins in a Colombian population, 2011-2015.

Science.gov (United States)

Torres, D R; Portilla, A; Machado-Duque, M E; Machado-Alba, J E

2017-12-01

Diabetes mellitus is a common disease among the general population and imposes considerable costs on health care systems. Insulin is used to treat type 1 diabetes mellitus and as an adjuvant to oral agents in advanced stages of type 2 diabetes mellitus. The objective was to describe the trends in use and cost of human and analogue insulins for Colombian patients. Descriptive retrospective analysis of prescriptions of human and analogue insulins on a monthly basis for the period from July 1, 2011 to February 2, 2015. Information was collected for the database population of two insurance companies. Frequencies and proportions were calculated; estimated economic impact was expressed as net cost and cost per thousand inhabitants per day. During the observation period, there was continuous growth in use of insulin, mainly in analogue forms (34.0% growth). At the start of the study, 10.4% of subjects were using an analogue insulin; this figure was 62.6% at the end of the study. In 2012, the average cost per 1000 inhabitants/day was US$1.7 for analogue and US$0.8 for human insulins. At the end of the observation period these costs had risen to US$9.2 for analogue (441.1% increase) and fallen to US$0.5 for human insulin (58.3% decrease). There has been an increase in the unit cost and frequency of use of insulin analogues for anti-diabetic therapy in Colombian patients. Moreover, there is controversy over whether insulin analogues are a more cost-effective treatment than human insulins for the general diabetic population. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Expression profiling of insulin action in human myotubes

DEFF Research Database (Denmark)

Hansen, L.; Gaster, Michael; Oakeley, E.J.

2004-01-01

Myotube cultures from patients with type 2 diabetes mellitus (T2DM) represent an experimental in vitro model of T2DM that offers a possibility to perform gene expression studies under standardized conditions. During a time-course of insulin stimulation (1 microM) at 5.5 mM glucose for 0 (no insulin......, metabolic enzymes, and finally cell cycle regulating genes. One-hundred-forty-four genes were differentially expressed in myotubes from donors with type 2 diabetes compared with control subjects, including HSP70, apolipoprotein D/E, tropomyosin, myosin, and actin previously reported from in vivo studies...... of diabetic skeletal muscle. We conclude, (i) that insulin induces a time-dependent inflammatory and pro-angiogenic transcriptional response in cultured human myotubes, (ii) that myotubes in vitro retain a gene expression pattern specific for type 2 diabetes and sharing five genes with that of type 2 diabetic...

RFX6 Regulates Insulin Secretion by Modulating Ca2+ Homeostasis in Human β Cells

Directory of Open Access Journals (Sweden)

Vikash Chandra

2014-12-01

Full Text Available Development and function of pancreatic β cells involve the regulated activity of specific transcription factors. RFX6 is a transcription factor essential for mouse β cell differentiation that is mutated in monogenic forms of neonatal diabetes. However, the expression and functional roles of RFX6 in human β cells, especially in pathophysiological conditions, are poorly explored. We demonstrate the presence of RFX6 in adult human pancreatic endocrine cells. Using the recently developed human β cell line EndoC-βH2, we show that RFX6 regulates insulin gene transcription, insulin content, and secretion. Knockdown of RFX6 causes downregulation of Ca2+-channel genes resulting in the reduction in L-type Ca2+-channel activity that leads to suppression of depolarization-evoked insulin exocytosis. We also describe a previously unreported homozygous missense RFX6 mutation (p.V506G that is associated with neonatal diabetes, which lacks the capacity to activate the insulin promoter and to increase Ca2+-channel expression. Our data therefore provide insights for understanding certain forms of neonatal diabetes.

The basal kinetic parameters of glycogen synthase in human myotube cultures are not affected by chronic high insulin exposure

DEFF Research Database (Denmark)

Gaster, M; Schrøder, H D; Handberg, A

2001-01-01

results show that chronic exposure of human myotubes to high insulin with or without high glucose did not affect the basal kinetic parameters but abolished the reactivity of GS to acute insulin stimulation. We suggest that insulin induced insulin resistance of GS is caused by a failure of acute insulin......There is no consensus regarding the results from in vivo and in vitro studies on the impact of chronic high insulin and/or high glucose exposure on acute insulin stimulation of glycogen synthase (GS) kinetic parameters in human skeletal muscle. The aim of this study was to evaluate the kinetic...... parameters of glycogen synthase activity in human myotube cultures at conditions of chronic high insulin combined or not with high glucose exposure, before and after a subsequent acute insulin stimulation. Acute insulin stimulation significantly increased the fractional activity (FV(0.1)) of GS, increased...

Comparison of insulin analogue B9AspB27Glu and soluble human insulin in insulin-treated diabetes.

Science.gov (United States)

Kang, S; Owens, D R; Vora, J P; Brange, J

1990-02-10

Postprandial plasma glucose excursions and plasma levels of free insulin after subcutaneous bolus injection of a rapidly absorbed monomeric insulin analogue (B9AspB27Glu) or soluble human insulin ('Actrapid HM' U100) were studied in six insulin-treated diabetic subjects. 10 U actrapid or an equimolar amount of the analogue were injected, in random order with an interval of 1 week, immediately before a 500 kcal test meal. Basal insulin levels were similar on the 2 study days (mean 74.1 [SE 5.1] pmol/l, actrapid; 79.7 [13.0] pmol/l, analogue). After injection of actrapid plasma free insulin levels rose slowly, reaching a plateau by 105 min at 222 (19) pmol/l. Injection of the analogue resulted in a rapid early peak at 30 min (798 [112] pmol/l), and levels were significantly higher than those after actrapid between 15 and 210 min. The more physiological plasma insulin levels achieved with the analogue were accompanied by a substantial reduction in postprandial plasma glucose excursions; the integrated area under the incremental plasma glucose curve was 45% lower after the analogue than after actrapid.

Monoclonal antibodies directed to human insulin-like growth factor I (IGF I)

International Nuclear Information System (INIS)

Laubli, U.K.; Baier, W.; Celio, M.R.; Binz, H.; Humbel, R.E.

1982-01-01

Mouse hybridomas secreting antibodies to human insulin-like growth factor I (IGF I) were produced by fusion of spleen cells of hyperimmunised mice with FO mouse-myeloma cells. Eight clones producing antibodies against human IGF I have been isolated, two of which have been characterised. One was used in a radioimmunoassay, the other for immunopurification of IGF. (Auth.)

Insulin resistance in human subjects having impaired glucose regulation

International Nuclear Information System (INIS)

Khan, S.H.; Khan, F.A.; Ijaz, A.

2007-01-01

To determine insulin resistance in human subjects having impaired glucose regulation (IGR) by Homeostasis Model Assessment for Insulin Resistance (HOMA-IR). A total of 100 subjects with impaired glucose regulation were selected for evaluation of metabolic syndrome as per the criteria of National Cholesterol Education Program, Adult Treatment Panel III (NCEP, ATP III), along with 47 healthy age and gender-matched controls. Physical examination to determine blood pressure and waist circumference was carried out and so was sampling for plasma glucose, serum triglycerides, HDL-cholesterol and insulin. Insulin resistance was calculated by the HOMA-IR. Finally, subjects with and without metabolic syndrome were compared with controls (n=47), using one-way ANOVA for studying insulin resistance between groups, with Tukey's post-hoc comparison. The frequency of finding metabolic syndrome in cases of IGR remained 47%. The insulin resistance demonstrated stepwise worsening from control population (mean=1.54, 95 % CI: 1.77 - 2.37) to subjects suffering from only IGR (mean=2.07, 95 % CI: 1.77- 2.37) to metabolic syndrome (mean=2.67, 95 %, CI: 2.34 - 3.00) (p < 0.001). Patients with impaired glucose regulation may have significant insulin resistance. It is, thus, recommended that a vigorous search be made to measure insulin resistance in all cases diagnosed to have impaired glucose regulation. (author)

Differences in glucose-stimulated insulin secretion in vitro of islets from human, nonhuman primate, and porcine origin.

Science.gov (United States)

Mueller, Kate R; Balamurugan, A N; Cline, Gary W; Pongratz, Rebecca L; Hooper, Rebecca L; Weegman, Bradley P; Kitzmann, Jennifer P; Taylor, Michael J; Graham, Melanie L; Schuurman, Henk-Jan; Papas, Klearchos K

2013-01-01

Porcine islet xenotransplantation is considered a potential cell-based therapy for type 1 diabetes. It is currently being evaluated in diabetic nonhuman primates (NHP) to assess safety and efficacy of the islet product. However, due to a variety of distinct differences between the respective species, including the insulin secretory characteristics of islets, the suitability and predictive value of the preclinical model in the extrapolation to the clinical setting remain a critical issue. Islets isolated from human (n = 3), NHP (n = 2), adult pig (AP, n = 3), and juvenile pig (JP, n = 4) pancreata were perifused with medium at basal glucose (2.5 mm) followed by high glucose (16.7 mm) concentrations. The total glucose-stimulated insulin secretion (GSIS) was calculated from generated insulin secretion profiles. Nonhuman primate islets exhibited GSIS 3-fold higher than AP islets, while AP and JP islets exhibited GSIS 1/3 and 1/30 of human islets, respectively. The insulin content of NHP and AP islets was similar to that of human islets, whereas that of JP islets was 1/5 of human islets. Despite the fact that human, NHP, and AP islets contain similar amounts of insulin, the much higher GSIS for NHP islets than for AP and JP islets suggests the need for increased dosing of islets from JP and AP in pig-to-NHP transplantation. Porcine islet xenotransplantation to humans may require significantly higher dosing given the lower GSIS of AP islets compared to human islets. © 2013 John Wiley & Sons A/S.

Expansion and conversion of human pancreatic ductal cells into insulin-secreting endocrine cells.

Science.gov (United States)

Lee, Jonghyeob; Sugiyama, Takuya; Liu, Yinghua; Wang, Jing; Gu, Xueying; Lei, Ji; Markmann, James F; Miyazaki, Satsuki; Miyazaki, Jun-Ichi; Szot, Gregory L; Bottino, Rita; Kim, Seung K

2013-11-19

Pancreatic islet β-cell insufficiency underlies pathogenesis of diabetes mellitus; thus, functional β-cell replacement from renewable sources is the focus of intensive worldwide effort. However, in vitro production of progeny that secrete insulin in response to physiological cues from primary human cells has proven elusive. Here we describe fractionation, expansion and conversion of primary adult human pancreatic ductal cells into progeny resembling native β-cells. FACS-sorted adult human ductal cells clonally expanded as spheres in culture, while retaining ductal characteristics. Expression of the cardinal islet developmental regulators Neurog3, MafA, Pdx1 and Pax6 converted exocrine duct cells into endocrine progeny with hallmark β-cell properties, including the ability to synthesize, process and store insulin, and secrete it in response to glucose or other depolarizing stimuli. These studies provide evidence that genetic reprogramming of expandable human pancreatic cells with defined factors may serve as a general strategy for islet replacement in diabetes. DOI: http://dx.doi.org/10.7554/eLife.00940.001.

Generation of glucose-responsive, insulin-producing cells from human umbilical cord blood-derived mesenchymal stem cells.

Science.gov (United States)

Prabakar, Kamalaveni R; Domínguez-Bendala, Juan; Molano, R Damaris; Pileggi, Antonello; Villate, Susana; Ricordi, Camillo; Inverardi, Luca

2012-01-01

We sought to assess the potential of human cord blood-derived mesenchymal stem cells (CB-MSCs) to derive insulin-producing, glucose-responsive cells. We show here that differentiation protocols based on stepwise culture conditions initially described for human embryonic stem cells (hESCs) lead to differentiation of cord blood-derived precursors towards a pancreatic endocrine phenotype, as assessed by marker expression and in vitro glucose-regulated insulin secretion. Transplantation of these cells in immune-deficient animals shows human C-peptide production in response to a glucose challenge. These data suggest that human cord blood may be a promising source for regenerative medicine approaches for the treatment of diabetes mellitus.

Lipid content and response to insulin are not invariably linked in human muscle cells

OpenAIRE

Aguer , Céline; Mercier , Jacques; Kitzmann , Magali

2009-01-01

Abstract In type 2 diabetes, a strong correlation between intramyocellular lipid accumulation and insulin resistance exists but whether intramyocellular accumulation is a cause or a consequence of insulin resistance is not clear. Lipid accumulation and response to insulin were evaluated in primary human myotubes derived from non-diabetic subjects and type 2 diabetic patients. Myotubes derived from type 2 diabetic patients had a defective response to insulin without showing a signif...

Effects of Insulin Detemir and NPH Insulin on Body Weight and Appetite-Regulating Brain Regions in Human Type 1 Diabetes: A Randomized Controlled Trial

NARCIS (Netherlands)

van Golen, L.W.; Veltman, D.J.; IJzerman, R.G.; Deijen, J.B.; Heijboer, A.C.; Barkhof, F.; Drent, M.L.; Diamant, M.

2014-01-01

Studies in rodents have demonstrated that insulin in the central nervous system induces satiety. In humans, these effects are less well established. Insulin detemir is a basal insulin analog that causes less weight gain than other basal insulin formulations, including the current standard

Effects of insulin detemir and NPH insulin on body weight and appetite-regulating brain regions in human type 1 diabetes: a randomized controlled trial

NARCIS (Netherlands)

van Golen, Larissa W.; Veltman, Dick J.; IJzerman, Richard G.; Deijen, Jan Berend; Heijboer, Annemieke C.; Barkhof, Frederik; Drent, Madeleine L.; Diamant, Michaela

2014-01-01

Studies in rodents have demonstrated that insulin in the central nervous system induces satiety. In humans, these effects are less well established. Insulin detemir is a basal insulin analog that causes less weight gain than other basal insulin formulations, including the current standard

Validation of methods for measurement of insulin secretion in humans in vivo

DEFF Research Database (Denmark)

Kjems, L L; Christiansen, E; Vølund, A

2000-01-01

To detect and understand the changes in beta-cell function in the pathogenesis of type 2 diabetes, an accurate and precise estimation of prehepatic insulin secretion rate (ISR) is essential. There are two common methods to assess ISR, the deconvolution method (by Eaton and Polonsky)-considered th......To detect and understand the changes in beta-cell function in the pathogenesis of type 2 diabetes, an accurate and precise estimation of prehepatic insulin secretion rate (ISR) is essential. There are two common methods to assess ISR, the deconvolution method (by Eaton and Polonsky...... of these mathematical techniques for quantification of insulin secretion have been tested in dogs, but not in humans. In the present studies, we examined the validity of both methods to recover the known infusion rates of insulin and C-peptide mimicking ISR during an oral glucose tolerance test. ISR from both......, and a close agreement was found for the results of an oral glucose tolerance test. We also studied whether C-peptide kinetics are influenced by somatostatin infusion. The decay curves after bolus injection of exogenous biosynthetic human C-peptide, the kinetic parameters, and the metabolic clearance rate were...

Differentiation of human-induced pluripotent stem cells into insulin-producing clusters.

Science.gov (United States)

Shaer, Anahita; Azarpira, Negar; Vahdati, Akbar; Karimi, Mohammad Hosein; Shariati, Mehrdad

2015-02-01

In diabetes mellitus type 1, beta cells are mostly destroyed; while in diabetes mellitus type 2, beta cells are reduced by 40% to 60%. We hope that soon, stem cells can be used in diabetes therapy via pancreatic beta cell replacement. Induced pluripotent stem cells are a kind of stem cell taken from an adult somatic cell by "stimulating" certain genes. These induced pluripotent stem cells may be a promising source of cell therapy. This study sought to produce isletlike clusters of insulin-producing cells taken from induced pluripotent stem cells. A human-induced pluripotent stem cell line was induced into isletlike clusters via a 4-step protocol, by adding insulin, transferrin, and selenium (ITS), N2, B27, fibroblast growth factor, and nicotinamide. During differentiation, expression of pancreatic β-cell genes was evaluated by reverse transcriptase-polymerase chain reaction; the morphologic changes of induced pluripotent stem cells toward isletlike clusters were observed by a light microscope. Dithizone staining was used to stain these isletlike clusters. Insulin produced by these clusters was evaluated by radio immunosorbent assay, and the secretion capacity was analyzed with a glucose challenge test. Differentiation was evaluated by analyzing the morphology, dithizone staining, real-time quantitative polymerase chain reaction, and immunocytochemistry. Gene expression of insulin, glucagon, PDX1, NGN3, PAX4, PAX6, NKX6.1, KIR6.2, and GLUT2 were documented by analyzing real-time quantitative polymerase chain reaction. Dithizone-stained cellular clusters were observed after 23 days. The isletlike clusters significantly produced insulin. The isletlike clusters could increase insulin secretion after a glucose challenge test. This work provides a model for studying the differentiation of human-induced pluripotent stem cells to insulin-producing cells.

Disruption of Mitochondria-Associated Endoplasmic Reticulum Membrane (MAM) Integrity Contributes to Muscle Insulin Resistance in Mice and Humans.

Science.gov (United States)

Tubbs, Emily; Chanon, Stéphanie; Robert, Maud; Bendridi, Nadia; Bidaux, Gabriel; Chauvin, Marie-Agnès; Ji-Cao, Jingwei; Durand, Christine; Gauvrit-Ramette, Daphné; Vidal, Hubert; Lefai, Etienne; Rieusset, Jennifer

2018-04-01

Modifications of the interactions between endoplasmic reticulum (ER) and mitochondria, defined as mitochondria-associated membranes (MAMs), were recently shown to be involved in the control of hepatic insulin action and glucose homeostasis, but with conflicting results. Whereas skeletal muscle is the primary site of insulin-mediated glucose uptake and the main target for alterations in insulin-resistant states, the relevance of MAM integrity in muscle insulin resistance is unknown. Deciphering the importance of MAMs on muscle insulin signaling could help to clarify this controversy. Here, we show in skeletal muscle of different mice models of obesity and type 2 diabetes (T2D) a marked disruption of ER-mitochondria interactions as an early event preceding mitochondrial dysfunction and insulin resistance. Furthermore, in human myotubes, palmitate-induced insulin resistance is associated with a reduction of structural and functional ER-mitochondria interactions. Importantly, experimental increase of ER-mitochondria contacts in human myotubes prevents palmitate-induced alterations of insulin signaling and action, whereas disruption of MAM integrity alters the action of the hormone. Lastly, we found an association between altered insulin signaling and ER-mitochondria interactions in human myotubes from obese subjects with or without T2D compared with healthy lean subjects. Collectively, our data reveal a new role of MAM integrity in insulin action of skeletal muscle and highlight MAM disruption as an essential subcellular alteration associated with muscle insulin resistance in mice and humans. Therefore, reduced ER-mitochondria coupling could be a common alteration of several insulin-sensitive tissues playing a key role in altered glucose homeostasis in the context of obesity and T2D. © 2018 by the American Diabetes Association.

Is Insulin Action in the Brain Relevant in Regulating Blood Glucose in Humans?

Science.gov (United States)

Dash, Satya; Xiao, Changting; Morgantini, Cecilia; Koulajian, Khajag; Lewis, Gary F

2015-07-01

In addition to its direct action on the liver to lower hepatic glucose production, insulin action in the central nervous system (CNS) also lowers hepatic glucose production in rodents after 4 hours. Although CNS insulin action (CNSIA) modulates hepatic glycogen synthesis in dogs, it has no net effect on hepatic glucose output over a 4-hour period. The role of CNSIA in regulating plasma glucose has recently been examined in humans and is the focus of this review. Intransal insulin (INI) administration increases CNS insulin concentration. Hence, INI can address whether CNSIA regulates plasma glucose concentration in humans. We and three other groups have sought to answer this question, with differing conclusions. Here we will review the critical aspects of each study, including its design, which may explain these discordant conclusions. The early glucose-lowering effect of INI is likely due to spillover of insulin into the systemic circulation. In the presence of simultaneous portal and CNS hyperinsulinemia, portal insulin action is dominant. INI administration does lower plasma glucose independent of peripheral insulin concentration (between ∼3 and 6 h after administration), suggesting that CNSIA may play a role in glucose homeostasis in the late postprandial period when its action is likely greatest and portal insulin concentration is at baseline. The potential physiological role and purpose of this pathway are discussed in this review. Because the effects of INI are attenuated in patients with type 2 diabetes and obesity, this is unlikely to be of therapeutic utility.

mRNA related to insulin family in human placenta

International Nuclear Information System (INIS)

Younes, M.A.; D'Agostino, J.B.; Frazier, M.L.; Besch, P.K.

1986-01-01

The authors have previously reported that human term placenta contains mRNA displaying sequence homology to a rat preproinsulin I cDNA clone (p119). When placental poly(A + ) RNA was analyzed for homology to p119 by RNA/DNA blot hybridization, prominent hybridization was observed which was found by densitometric analysis to be three-fold higher than control. To further characterize this insulin-like message, a cDNA library was generated (approx.7000 transformants) using normal term cesarean-sectioned tissue to prepare placental poly(A + ) RNA templates. Five hundred transformants were initially screened by colony hybridization using a 32 P-labeled rat preproinsulin I cDNA as probe. Of the ten initial positives obtained, three were found to be true positives based on Southern hybridization analyses of the recombinant plasmids. Using Taq I digested pBr322 as a size marker, the cDNAs were found to be approximately 300 bp in length. Preliminary DNA sequencing using the Sanger dideoxy chain termination method has revealed that one of these clones displays significant homology to the 5' region of human insulin-like growth factors I and II

mRNA related to insulin family in human placenta

Energy Technology Data Exchange (ETDEWEB)

Younes, M.A.; D' Agostino, J.B.; Frazier, M.L.; Besch, P.K.

1986-03-01

The authors have previously reported that human term placenta contains mRNA displaying sequence homology to a rat preproinsulin I cDNA clone (p119). When placental poly(A/sup +/) RNA was analyzed for homology to p119 by RNA/DNA blot hybridization, prominent hybridization was observed which was found by densitometric analysis to be three-fold higher than control. To further characterize this insulin-like message, a cDNA library was generated (approx.7000 transformants) using normal term cesarean-sectioned tissue to prepare placental poly(A/sup +/) RNA templates. Five hundred transformants were initially screened by colony hybridization using a /sup 32/P-labeled rat preproinsulin I cDNA as probe. Of the ten initial positives obtained, three were found to be true positives based on Southern hybridization analyses of the recombinant plasmids. Using Taq I digested pBr322 as a size marker, the cDNAs were found to be approximately 300 bp in length. Preliminary DNA sequencing using the Sanger dideoxy chain termination method has revealed that one of these clones displays significant homology to the 5' region of human insulin-like growth factors I and II.

Human milk insulin is related to maternal plasma insulin and BMI: but other components of human milk do not differ by BMI.

Science.gov (United States)

Young, B E; Patinkin, Z; Palmer, C; de la Houssaye, B; Barbour, L A; Hernandez, T; Friedman, J E; Krebs, N F

2017-09-01

The impact of maternal BMI and insulin sensitivity on bioactive components of human milk (HM) is not well understood. As the prevalence of obesity and diabetes rises, it is increasingly critical that we understand how maternal BMI and hormones associated with metabolic disease relate to concentrations of bioactive components in HM. This longitudinal cohort design followed 48 breastfeeding mothers through the first four months of lactation, collecting fasting morning HM samples at 2-weeks and 1, 2, 3 and 4-months, and fasting maternal blood at 2-weeks and 4-months. Insulin, glucose, adipokines leptin and adiponectin, appetite regulating hormone ghrelin, marker of oxidative stress 8OHdG and inflammatory cytokines (IL-6, IL-8, and TNF-a) were measured in HM and maternal plasma. A total of 26 normal weight (NW) (BMI=21.4±2.0 kg/m 2 ) and 22 overweight/obese (OW/Ob) (BMI=30.4±4.2 kg/m 2 ) were followed. Of all HM analytes measured, only insulin and leptin were different between groups - consistently higher in the OW/Ob group (leptin: P<0.001; insulin: P<0.03). HM insulin was 98% higher than maternal plasma insulin at 2-weeks and 32% higher at 4-months (P<0.001). Maternal fasting plasma insulin and HOMA-IR were positively related to HM insulin at 2-weeks (P<0.001, R 2 ⩾0.38, n=31), and 4-months (P⩽0.005, R 2 ⩾0.20, n=38). The concentrations of insulin in HM are higher than in maternal plasma and are related to maternal BMI and insulin sensitivity. With the exception of leptin, there were minimal other differences observed in HM composition across a wide range in maternal BMI.

Palmitate and insulin synergistically induce IL-6 expression in human monocytes

Directory of Open Access Journals (Sweden)

Lumpkin Charles K

2010-11-01

Full Text Available Abstract Background Insulin resistance is associated with a proinflammatory state that promotes the development of complications such as type 2 diabetes mellitus (T2DM and atherosclerosis. The metabolic stimuli that initiate and propagate proinflammatory cytokine production and the cellular origin of proinflammatory cytokines in insulin resistance have not been fully elucidated. Circulating proinflammatory monocytes show signs of enhanced inflammation in obese, insulin resistant subjects and are thus a potential source of proinflammatory cytokine production. The specific, circulating metabolic factors that might stimulate monocyte inflammation in insulin resistant subjects are poorly characterized. We have examined whether saturated nonesterified fatty acids (NEFA and insulin, which increase in concentration with developing insulin resistance, can trigger the production of interleukin (IL-6 and tumor necrosis factor (TNF-α in human monocytes. Methods Messenger RNA and protein levels of the proinflammatory cytokines IL-6 and TNF-α were measured by quantitative real-time PCR (qRT-PCR and Luminex bioassays. Student's t-test was used with a significance level of p Results Esterification of palmitate with coenzyme A (CoA was necessary, while β-oxidation and ceramide biosynthesis were not required, for the induction of IL-6 and TNF-α in THP-1 monocytes. Monocytes incubated with insulin and palmitate together produced more IL-6 mRNA and protein, and more TNF-α protein, compared to monocytes incubated with palmitate alone. Incubation of monocytes with insulin alone did not affect the production of IL-6 or TNF-α. Both PI3K-Akt and MEK/ERK signalling pathways are important for cytokine induction by palmitate. MEK/ERK signalling is necessary for synergistic induction of IL-6 by palmitate and insulin. Conclusions High levels of saturated NEFA, such as palmitate, when combined with hyperinsulinemia, may activate human monocytes to produce

The effect of feeding frequency on insulin and ghrelin responses in human subjects

DEFF Research Database (Denmark)

Solomon, Thomas; Chambers, Edward S; Jeukendrup, Asker E

2008-01-01

Recent work shows that increased meal frequency reduces ghrelin responses in sheep. Human research suggests there is an interaction between insulin and ghrelin. The effect of meal frequency on this interaction is unknown. Therefore, we investigated the effect of feeding frequency on insulin...... and ghrelin responses in human subjects. Five healthy male volunteers were recruited from the general population: age 24 (SEM 2)years, body mass 75.7 (SEM 3.2) kg and BMI 23.8 (SEM 0.8) kg/m(2). Volunteers underwent three 8-h feeding regimens: fasting (FAST); low-frequency(two) meal ingestion (LOFREQ......(MEAL)); high-frequency (twelve) meal ingestion (HIFREQ(MEAL)). Meals were equi-energetic within trials,consisting of 64% carbohydrate, 23% fat and 13% protein. Total energy intake was equal between feeding trials. Total area under the curve for serum insulin and plasma ghrelin responses did not differ between...

Enzymatic amplification of a flow-injected thermometric enzyme-linked immunoassay for human insulin.

Science.gov (United States)

Mecklenburg, M; Lindbladh, C; Li, H; Mosbach, K; Danielsson, B

1993-08-01

A flow-injected thermometric enzyme linked immunoassay for human insulin which employs the lactate dehydrogenase/lactate oxidase (LDH/LOD) substrate recycling system for signal amplification is described. The system is composed of two columns, an immunosorbent column containing immobilized anti-insulin antibodies for sensing and a recycling column containing immobilized LDH/LOD/Catalase for detection. The effect of flow rates, conjugate concentrations, and chromatographic support material upon the sensitivity of the assay are investigated. The assay has a detection limit of 0.025 microgram/ml and a linear range from 0.05 to 2 micrograms/ml. This corresponds to a 10-fold increase in sensitivity over the unamplified system. A recombinant human insulin-proinsulin conjugate was also tested. The results show that enzymatic amplification can be employed to increase the sensitivity and reproducibility of flow injection assay-based biosensors. The implications of these results upon on-line analysis are discussed.

PKCδ regulates hepatic insulin sensitivity and hepatosteatosis in mice and humans

DEFF Research Database (Denmark)

Bezy, Olivier; Tran, Thien T; Pihlajamäki, Jussi

2011-01-01

C57BL/6J and 129S6/Sv (B6 and 129) mice differ dramatically in their susceptibility to developing diabetes in response to diet- or genetically induced insulin resistance. A major locus contributing to this difference has been mapped to a region on mouse chromosome 14 that contains the gene encoding...... tolerance, and reduced hepatosteatosis with aging. Conversely, mice with liver-specific overexpression of PKCδ developed hepatic insulin resistance characterized by decreased insulin signaling, enhanced lipogenic gene expression, and hepatosteatosis. Therefore, changes in the expression and regulation...... of PKCδ between strains of mice and in obese humans play an important role in the genetic risk of hepatic insulin resistance, glucose intolerance, and hepatosteatosis; and thus PKCδ may be a potential target in the treatment of metabolic syndrome....

Insulin resistance and the mitochondrial link. Lessons from cultured human myotubes

DEFF Research Database (Denmark)

Gaster, Michael

2007-01-01

In order to better understand the impact of reduced mitochondrial function for the development of insulin resistance and cellular metabolism, human myotubes were established from lean, obese, and T2D subjects and exposed to mitochondrial inhibitors, either affecting the electron transport chain...... lipid uptake. The metabolic phenotype during respiratory uncoupling resembled the above picture, except for an increase in glucose and palmitate oxidation. Antimycin A and oligomycin treatment induced insulin resistance at the level of glucose and palmitate uptake in all three study groups while......, at the level of glycogen synthesis, insulin resistance was only seen in lean myotubes. Primary insulin resistance in diabetic myotubes was significantly worsened at the level of glucose and lipid uptake. The present study is the first convincing data linking functional mitochondrial impairment per se...

Effect of alcohol on insulin secretion and viability of human pancreatic islets

Directory of Open Access Journals (Sweden)

Nikolić Dragan

2017-01-01

Full Text Available Introduction/Objective. There are controversial data in the literature on the topic of effects of alcohol on insulin secretion, apoptosis, and necrosis of the endocrine and exocrine pancreas. The goal of this research was to determine how alcohol affects the insulin secretion and viability of human adult pancreatic islets in vitro during a seven-day incubation. Methods. Human pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated in Roswell Park Memorial Institute (RPMI medium containing alcohol (10 μl of alcohol in 100 ml of medium. Insulin stimulation index (SI and viability of the islets were determined on the first, third, and seventh day of cultivation. Results. Analysis of the viability of the islets showed that there wasn’t significant difference between the control and the test group. In the test group, viability of the cultures declined with the time of incubation. SI of the test group was higher compared to the control group, by 50% and 25% on the first and third day of cultivation, respectively. On the seventh day, insulin secretion was reduced by 25%. The difference was not statistically significant (p > 0.05. In the test group, significant decline in insulin secretion was found on the third and seventh day of incubation (p ≤ 0.05. Conclusion. Alcohol can increase or decrease insulin secretion of islets cultures, which may result in an inadequate response of pancreatic β-cells to blood glucose, leading to insulin resistance, and increased risk of developing type 2 diabetes. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 41002

The effect of exercise on the absorption of inhaled human insulin in healthy volunteers

DEFF Research Database (Denmark)

Petersen, Astrid Heide; Kohler, Gerd; Korsatko, Stefan

2008-01-01

overall absorption. Aims To investigate the effect of moderate exercise on the absorption of inhaled insulin. Methods A single-centre, randomized, open-label, three-period cross-over trial was carried out in 12 nonsmoking healthy subjects. A dose of 3.5 mg inhaled human insulin was administered via...

Short-and long-term glucocorticoid treatment enhances insulin signalling in human subcutaneous adipose tissue

OpenAIRE

Gathercole, LL; Morgan, SA; Bujalska, IJ; Stewart, PM; Tomlinson, JW

2011-01-01

Background: Endogenous or exogenous glucocorticoid (GC) excess (Cushing's syndrome) is characterized by increased adiposity and insulin resistance. Although GCs cause global insulin resistance in vivo, we have previously shown that GCs are able to augment insulin action in human adipose tissue, contrasting with their action in skeletal muscle. Cushing's syndrome develops following chronic GC exposure and, in addition, is a state of hyperinsulinemia. Objectives: We have therefore compared the ...

Generation of high-yield insulin producing cells from human bone marrow mesenchymal stem cells.

Science.gov (United States)

Jafarian, Arefeh; Taghikhani, Mohammad; Abroun, Saeid; Pourpak, Zahra; Allahverdi, Amir; Soleimani, Masoud

2014-07-01

Allogenic islet transplantation is a most efficient approach for treatment of diabetes mellitus. However, the scarcity of islets and long term need for an immunosuppressant limits its application. Recently, cell replacement therapies that generate of unlimited sources of β cells have been developed to overcome these limitations. In this study we have described a stage specific differentiation protocol for the generation of insulin producing islet-like clusters from human bone marrow mesenchymal stem cells (hBM-MSCs). This specific stepwise protocol induced differentiation of hMSCs into definitive endoderm, pancreatic endoderm and pancreatic endocrine cells that expressed of sox17, foxa2, pdx1, ngn3, nkx2.2, insulin, glucagon, somatostatin, pancreatic polypeptide, and glut2 transcripts respectively. In addition, immunocytochemical analysis confirmed protein expression of the above mentioned genes. Western blot analysis discriminated insulin from proinsulin in the final differentiated cells. In derived insulin producing cells (IPCs), secreted insulin and C-peptide was in a glucose dependent manner. We have developed a protocol that generates effective high-yield human IPCs from hBM-MSCs in vitro. These finding suggest that functional IPCs generated by this procedure can be used as a cell-based approach for insulin dependent diabetes mellitus.

Comparison of subcutaneous soluble human insulin and insulin analogues (AspB9, GluB27; AspB10; AspB28) on meal-related plasma glucose excursions in type I diabetic subjects.

Science.gov (United States)

Kang, S; Creagh, F M; Peters, J R; Brange, J; Vølund, A; Owens, D R

1991-07-01

To compare postprandial glucose excursions and plasma free insulin-analogue levels after subcutaneous injection of three novel human insulin analogues (AspB10; AspB9, GluB27; and AspB28) with those after injection of soluble human insulin (Actrapid HM U-100). Six male subjects with insulin-dependent diabetes, at least 1 wk apart and after an overnight fast and basal insulin infusion, received 72 nmol (approximately 12 U) s.c. of soluble human insulin 30 min before, or 72 nmol of each of the three analogues immediately before, a standard 500-kcal meal. Mean basal glucoses were similar on the 4 study days. Compared to human insulin (6.3 +/- 0.8 mM), mean +/- SE peak incremental glucose rises were similar after analogues AspB10 (5.4 +/- 0.8 mM) and AspB9, GluB27 (5.4 +/- 0.7 mM) and significantly lower after analogue AspB28 (3.6 +/- 1.2 mM, P less than 0.02). Relative to soluble human insulin (100% +/- SE21), incremental areas under the glucose curve between 0 and 240 min were 79% +/- 34 (AspB10, NS), 70% +/- 29 (AspB9, GluB27, NS), and 43% +/- 23 (AspB28, P less than 0.02). Basal plasma free insulin levels were similar on the 4 study days. Plasma free insulin-analogue levels rose rapidly to peak 30 min after injection at 308 +/- 44 pM (AspB10); 1231 +/- 190 pM (AspB9, GluB27) and 414 +/- 42 pM (AspB28) and were significantly higher than corresponding (i.e., 30 min postmeal) plasma free insulin levels of 157 +/- 15 pM (P less than 0.02 in each case). Plasma profiles of the insulin analogues were more physiological than that of human insulin after subcutaneous injection. All three analogues given immediately before the meal are at least as effective as soluble human insulin given 30 min earlier. These analogues are promising potential candidates for short-acting insulins of the future.

Reversal of hyperglycemia in mice by using human expandable insulin-producing cells differentiated from fetal liver progenitor cells

Science.gov (United States)

Zalzman, Michal; Gupta, Sanjeev; Giri, Ranjit K.; Berkovich, Irina; Sappal, Baljit S.; Karnieli, Ohad; Zern, Mark A.; Fleischer, Norman; Efrat, Shimon

2003-06-01

Beta-cell replacement is considered to be the most promising approach for treatment of type 1 diabetes. Its application on a large scale is hindered by a shortage of cells for transplantation. Activation of insulin expression, storage, and regulated secretion in stem/progenitor cells offers novel ways to overcome this shortage. We explored whether fetal human progenitor liver cells (FH) could be induced to differentiate into insulin-producing cells after expression of the pancreatic duodenal homeobox 1 (Pdx1) gene, which is a key regulator of pancreatic development and insulin expression in beta cells. FH cells possess a considerable replication capacity, and this was further extended by introduction of the gene for the catalytic subunit of human telomerase. Immortalized FH cells expressing Pdx1 activated multiple beta-cell genes, produced and stored considerable amounts of insulin, and released insulin in a regulated manner in response to glucose. When transplanted into hyperglycemic immunodeficient mice, the cells restored and maintained euglycemia for prolonged periods. Quantitation of human C-peptide in the mouse serum confirmed that the glycemia was normalized by the transplanted human cells. This approach offers the potential of a novel source of cells for transplantation into patients with type 1 diabetes.

Insulin increases phosphorylation of mitochondrial proteins in human skeletal muscle in vivo

DEFF Research Database (Denmark)

Zhao, Xiaolu; Bak, Steffen; Pedersen, Andreas James Thestrup

2014-01-01

, we investigated the effect of insulin on the phosphorylation of mitochondrial proteins in human skeletal muscle in vivo. Using a combination of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC−MS/MS, we compared the phosphoproteomes of isolated mitochondria from skeletal muscle samples...... obtained from healthy individuals before and after 4 h of insulin infusion. In total, we identified 207 phosphorylation sites in 95 mitochondrial proteins. Of these phosphorylation sites, 45% were identified in both basal and insulin-stimulated samples. Insulin caused a 2-fold increase in the number...... of different mitochondrial phosphopeptides (87 ± 7 vs 40 ± 7, p = 0.015) and phosphoproteins (46 ± 2 vs 26 ± 3, p = 0.005) identified in each mitochondrial preparation. Almost half of the mitochondrial phosphorylation sites (n = 94) were exclusively identified in the insulin-stimulated state and included...

Nasal insulin changes peripheral insulin sensitivity simultaneously with altered activity in homeostatic and reward-related human brain regions.

Science.gov (United States)

Heni, M; Kullmann, S; Ketterer, C; Guthoff, M; Linder, K; Wagner, R; Stingl, K T; Veit, R; Staiger, H; Häring, H-U; Preissl, H; Fritsche, A

2012-06-01

Impaired insulin sensitivity is a major factor leading to type 2 diabetes. Animal studies suggest that the brain is involved in the regulation of insulin sensitivity. We investigated whether insulin action in the human brain regulates peripheral insulin sensitivity and examined which brain areas are involved. Insulin and placebo were given intranasally. Plasma glucose, insulin and C-peptide were measured in 103 participants at 0, 30 and 60 min. A subgroup (n = 12) was also studied with functional MRI, and blood sampling at 0, 30 and 120 min. For each time-point, the HOMA of insulin resistance (HOMA-IR) was calculated as an inverse estimate of peripheral insulin sensitivity. Plasma insulin increased and subsequently decreased. This excursion was accompanied by slightly decreased plasma glucose, resulting in an initially increased HOMA-IR. At 1 h after insulin spray, the HOMA-IR subsequently decreased and remained lower up to 120 min. An increase in hypothalamic activity was observed, which correlated with the increased HOMA-IR at 30 min post-spray. Activity in the putamen, right insula and orbitofrontal cortex correlated with the decreased HOMA-IR at 120 min post-spray. Central insulin action in specific brain areas, including the hypothalamus, may time-dependently regulate peripheral insulin sensitivity. This introduces a potential novel mechanism for the regulation of peripheral insulin sensitivity and underlines the importance of cerebral insulin action for the whole organism.

ADAMTS13 expression in human chondrosarcoma cells induced by insulin

Directory of Open Access Journals (Sweden)

Rıdvan Fırat

2014-06-01

Full Text Available Objectives: A Disintegrin-like Metalloproteinase with Thrombospondin Motifs (ADAMTS proteins is a proteinase enzyme group that primarily located in the extracellular matrix (ECM. Insulin has been known to stimulate proteoglycan biosynthesis in chondrosarcoma chondrocytes and thereby the levels of ADAMTS proteins. The aim of this study is to evaluate the time-dependent effects of insulin on the ADAMTS13 expression in OUMS-27 human chondrosarcoma cell line to test the hypothesis that insulin diminishes ADAMTS13 expression because of its anabolic effects. Methods: To test this hypothesis OUMS-27 cells were cultured in Dulbecco’s modified Eagle’ medium (DMEM containing 10μg/mL insulin. The medium containing insulin was changed every other day up to 11th day. Cells were harvested at 1, 3, 7, and 11th days and protein and RNA isolations were performed at the proper times. The levels of RNA expression of ADAMTS13 was quantified by qRT-PCR using appropriate primers while protein levels was detected by Western blot technique using anti-ADAMTS13 antibody. Results: Although there was a decrease in both RNA and protein levels in insulin-applied groups compared to the control cells, it was not statistically significant. Conclusion: Under the light of our findings, it is suggested that insulin does not participate in regulation of ADAMTS13 in OUMS-27 chondrosarcoma cells. J Clin Exp Invest 2014; 5 (2: 226-232

Human Liver Cells Expressing Albumin and Mesenchymal Characteristics Give Rise to Insulin-Producing Cells

Directory of Open Access Journals (Sweden)

Irit Meivar-Levy

2011-01-01

Full Text Available Activation of the pancreatic lineage in the liver has been suggested as a potential autologous cell replacement therapy for diabetic patients. Transcription factors-induced liver-to-pancreas reprogramming has been demonstrated in numerous species both in vivo and in vitro. However, human-derived liver cells capable of acquiring the alternate pancreatic repertoire have never been characterized. It is yet unknown whether hepatic-like stem cells or rather adult liver cells give rise to insulin-producing cells. Using an in vitro experimental system, we demonstrate that proliferating adherent human liver cells acquire mesenchymal-like characteristics and a considerable level of cellular plasticity. However, using a lineage-tracing approach, we demonstrate that insulin-producing cells are primarily generated in cells enriched for adult hepatic markers that coexpress both albumin and mesenchymal markers. Taken together, our data suggest that adult human hepatic tissue retains a substantial level of developmental plasticity, which could be exploited in regenerative medicine approaches.

High-level expression of human insulin receptor cDNA in mouse NIH 3T3 cells

International Nuclear Information System (INIS)

Whittaker, J.; Okamoto, A.K.; Thys, R.; Bell, G.I.; Steiner, D.F.; Hofmann, C.A.

1987-01-01

In order to develop a simple, efficient system for the high-level expression of human insulin receptors in eukaryotic cells, a full-length human kidney insulin receptor cDNA was inserted into a bovine papilloma virus vector under the control of the mouse metallothionein promoter. After transfection of mouse NIH 3T3 cells with this construct, seven cell lines expressing insulin receptors were isolated; two cell lines had more than 10 6 receptors per cell. The cell line with the highest 125 I-insulin binding (NIH 3T3 HIR3.5) had 6 x 10 6 receptors with a K/sub d/ of 10 -9 M. This level was not dependent on exposure to metals but could be increased further to 2 x 10 7 receptors per cell by addition of sodium butyrate to the culture medium. The α and β subunits had apparent molecular weights of 147,000 and 105,000, respectively (compared to 135,000 and 95,000 in IM-9 human lymphocytes), values identical to those of the α and β subunits of the insulin receptors of nontransformed NIH 3T3 cells. This size difference was due to altered carbohydrate composition, as N-glycanase digestion reduced the apparent receptor subunit size of the transfected cells and IM-9 lymphocytes to identical values. The alteration in N-linked oligosaccharide composition could not be ascribed to differences in the kinetics of posttranslational processing of the insulin receptors, which was comparable to that of other cells studied. The basal rate of glycogen synthesis in the cells overexpressing insulin receptors was increased 4- to 5-fold compared with controls. Low levels of added insulin (0.1 nM) caused a 50% increase in the rate of glycogen synthesis

Structural analogs of human insulin-like growth factor I with reduced affinity for serum binding proteins and the type 2 insulin-like growth factor receptor

International Nuclear Information System (INIS)

Bayne, M.L.; Applebaum, J.; Chicchi, G.G.; Hayes, N.S.; Green, B.G.; Cascieri, M.A.

1988-01-01

Four structural analogs of human insulin-like growth factor I (hIGF-I) have been prepared by site-directed mutagenesis of a synthetic IGF-I gene and subsequent expression and purification of the mutant protein from the conditioned media of transformed yeast. [Phe -1 , Val 1 , Asn 2 , Gln 3 , His 4 , Ser 8 , His 9 , Glu 12 , Tyr 15 , Leu 16 ]IGF-I (B-chain mutant), in which the first 16 amino acids of hIGF-I were replaced with the first 17 amino acids of the B-chain of insulin, has >1000-, 100-, and 2-fold reduced potency for human serum binding proteins, the rat liver type 2 IGF receptor, and the human placental type 1 IGF receptor, respectively. The B-chain mutant also has 4-fold increased affinity for the human placental insulin receptor. [Gln 3 , Ala 4 ] IGF-I has 4-fold reduced affinity for human serum binding proteins, but is equipotent to hIGF-I at the types 1 and 2 IGF and insulin receptors. [Tyr 15 , Leu 16 ] IGH-I has 4-fold reduced affinity for human serum binding proteins and 10-fold increased affinity for the insulin receptor. The peptide in which these four-point mutations are combined, [Gln 3 , Ala 4 , Tyr 15 ,Leu 16 ]IGF-I, has 600-fold reduced affinity for the serum binding proteins. All four of these mutants stimulate DNA synthesis in the rat vascular smooth muscle cell line A10 with potencies reflecting their potency at the type 1 IGF receptor. These studies identify some of the domains of hIGF-I which are responsible for maintaining high affinity binding with the serum binding protein and the type 2 IGF receptor. In addition, These peptides will be useful in defining the role of the type 2 IGF receptor and serum binding proteins in the physiological actions of hIGF-I

Hepatic Diacylglycerol-Associated Protein Kinase Cε Translocation Links Hepatic Steatosis to Hepatic Insulin Resistance in Humans

NARCIS (Netherlands)

ter Horst, Kasper W.; Gilijamse, Pim W.; Versteeg, Ruth I.; Ackermans, Mariette T.; Nederveen, Aart J.; la Fleur, Susanne E.; Romijn, Johannes A.; Nieuwdorp, Max; Zhang, Dongyan; Samuel, Varman T.; Vatner, Daniel F.; Petersen, Kitt F.; Shulman, Gerald I.; Serlie, Mireille J.

2017-01-01

Hepatic lipid accumulation has been implicated in the development of insulin resistance, but translational evidence in humans is limited. We investigated the relationship between liver fat and tissue-specific insulin sensitivity in 133 obese subjects. Although the presence of hepatic steatosis in

Destabilization of Human Insulin Fibrils by Peptides of Fruit Bromelain Derived From Ananas comosus (Pineapple).

Science.gov (United States)

Das, Sromona; Bhattacharyya, Debasish

2017-12-01

Deposition of insulin aggregates in human body leads to dysfunctioning of several organs. Effectiveness of fruit bromelain from pineapple in prevention of insulin aggregate was investigated. Proteolyses of bromelain was done as par human digestive system and the pool of small peptides was separated from larger peptides and proteins. Under conditions of growth of insulin aggregates from its monomers, this pool of peptides restricted the reaction upto formation of oligomers of limited size. These peptides also destabilized preformed insulin aggregates to oligomers. These processes were followed fluorimetrically using Thioflavin T and 1-ANS, size-exclusion HPLC, dynamic light scattering, atomic force microscopy, and transmission electron microscopy. Sequences of insulin (A and B chains) and bromelain were aligned using Clustal W software to predict most probable sites of interactions. Synthetic tripeptides corresponding to the hydrophobic interactive sites of bromelain showed disaggregation of insulin suggesting specificity of interactions. The peptides GG and AAA serving as negative controls showed no potency in destabilization of aggregates. Disaggregation potency of the peptides was also observed when insulin was deposited on HepG2 liver cells where no formation of toxic oligomers occurred. Amyloidogenic des-octapeptide (B23-B30 of insulin) incapable of cell signaling showed cytotoxicity similar to insulin. This toxicity could be neutralized by bromelain derived peptides. FT-IR and far-UV circular dichroism analysis indicated that disaggregated insulin had structure distinctly different from that of its hexameric (native) or monomeric states. Based on the stoichiometry of interaction and irreversibility of disaggregation, the mechanism/s of the peptides and insulin interactions has been proposed. J. Cell. Biochem. 118: 4881-4896, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Intracellular insulin-receptor dissociation and segregation in a rat fibroblast cell line transfected with a human insulin receptor gene

International Nuclear Information System (INIS)

Levy, J.R.; Olefsky, J.M.

1988-01-01

The cellular processing of insulin and insulin receptors was studied using a rat fibroblast cell line that had been transfected with a normal human insulin receptor gene, expressing approximately 500 times the normal number of native fibroblasts insulin receptors. These cells bind and internalize insulin normally. Biochemically assays based on the selective precipitation by polyethylene glycol of intact insulin-receptor complexes but not of free intracellular insulin were developed to study the time course of intracellular insulin-receptor dissociation. Fibroblasts were incubated with radiolabeled insulin at 4 0 C, and internalization of insulin-receptor complexes was initiated by warming the cells to 37 0 C. Within 2 min, 90% of the internalized radioactivity was composed of intact insulin-receptor complexes. The dissociation of insulin from internalized insulin-receptor complexes was markedly inhibited by monensin and chloroquine. Furthermore, chloroquine markedly increased the number of cross-linkable intracellular insulin-receptor complexes, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography. These findings suggest that acidification of intracellular vesicles is responsible for insulin-receptor dissociation. Physical segregation of dissociated intracellular insulin from its receptor was monitored. The results are consistent with the view that segregation of insulin and receptor occurs 5-10 min after initiation of dissociation. These studies demonstrate the intracellular itinerary of insulin-receptor complexes, including internalization, dissociation of insulin from the internalized receptor within an acidified compartment, segregation of insulin from the receptor, and subsequent ligand degradation

Effect of Human Myotubes-Derived Media on Glucose-Stimulated Insulin Secretion

Directory of Open Access Journals (Sweden)

Maria L. Mizgier

2017-01-01

Full Text Available Fasting to postprandial transition requires a tight adjustment of insulin secretion to its demand, so tissue (e.g., skeletal muscle glucose supply is assured while hypo-/hyperglycemia are prevented. High muscle glucose disposal after meals is pivotal for adapting to increased glycemia and might drive insulin secretion through muscle-released factors (e.g., myokines. We hypothesized that insulin influences myokine secretion and then increases glucose-stimulated insulin secretion (GSIS. In conditioned media from human myotubes incubated with/without insulin (100 nmol/L for 24 h, myokines were qualitatively and quantitatively characterized using an antibody-based array and ELISA-based technology, respectively. C57BL6/J mice islets and Wistar rat beta cells were incubated for 24 h with control and conditioned media from noninsulin- and insulin-treated myotubes prior to GSIS determination. Conditioned media from insulin-treated versus nontreated myotubes had higher RANTES but lower IL6, IL8, and MCP1 concentration. Qualitative analyses revealed that conditioned media from noninsulin- and insulin-treated myotubes expressed 32 and 23 out of 80 myokines, respectively. Islets incubated with conditioned media from noninsulin-treated myotubes had higher GSIS versus control islets (p<0.05. Meanwhile, conditioned media from insulin-treated myotubes did not influence GSIS. In beta cells, GSIS was similar across conditions. In conclusion, factors being present in noninsulin-stimulated muscle cell-derived media appear to influence GSIS in mice islets.

Insulin redirects differentiation from cardiogenic mesoderm and endoderm to neuroectoderm in differentiating human embryonic stem cells.

NARCIS (Netherlands)

Freund, C.M.A.H.; Ward-van Oostwaard, D.; Monshouwer-Kloots, J.; van den Brink, S.; van Rooijen, M.A.; Xu, X.; Zweigerdt, R.; Mummery, C.L.; Passier, R.

2008-01-01

Human embryonic stem cells (hESC) can proliferate indefinitely while retaining the capacity to form derivatives of all three germ layers. We have reported previously that hESC differentiate into cardiomyocytes when cocultured with a visceral endoderm-like cell line (END-2). Insulin/insulin-like

Complete sequence-specific 1H NMR assignments for human insulin

International Nuclear Information System (INIS)

Kline, A.D.; Justice, R.M. Jr.

1990-01-01

Solvent conditions where human insulin could be studied by high-resolution NMR were determined. Both low pH and addition of acetonitrile were required to overcome the protein's self-association and to obtain useful spectra. Two hundred eighty-six 1 H resonances were located and assigned to specific sites on the protein by using two-dimensional NMR methods. The presence and position of numerous d NN sequential NOE's indicate that the insulin conformation seen in crystallographic studies is largely retained under these solution conditions. Slowly exchanging protons were observed for seven backbone amide protons and were assigned to positions A15 and A16 and to positions B15-B19. These amides all occur within helical regions of the protein

Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro.

Directory of Open Access Journals (Sweden)

Holger A Russ

Full Text Available Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, attempts at expanding human islet cells in tissue culture result in loss of beta-cell phenotype. Using a lineage-tracing approach we provided evidence for massive proliferation of beta-cell-derived (BCD cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT. Epigenetic analyses indicate that key beta-cell genes maintain open chromatin structure in expanded BCD cells, although they are not transcribed. Here we investigated whether BCD cells can be redifferentiated into beta-like cells.Redifferentiation conditions were screened by following activation of an insulin-DsRed2 reporter gene. Redifferentiated cells were characterized for gene expression, insulin content and secretion assays, and presence of secretory vesicles by electron microscopy. BCD cells were induced to redifferentiate by a combination of soluble factors. The redifferentiated cells expressed beta-cell genes, stored insulin in typical secretory vesicles, and released it in response to glucose. The redifferentiation process involved mesenchymal-epithelial transition, as judged by changes in gene expression. Moreover, inhibition of the EMT effector SLUG (SNAI2 using shRNA resulted in stimulation of redifferentiation. Lineage-traced cells also gave rise at a low rate to cells expressing other islet hormones, suggesting transition of BCD cells through an islet progenitor-like stage during redifferentiation.These findings demonstrate for the first time that expanded dedifferentiated beta cells can be induced to redifferentiate in culture. The findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug

Redifferentiation of insulin-secreting cells after in vitro expansion of adult human pancreatic islet tissue

International Nuclear Information System (INIS)

Lechner, Andreas; Nolan, Anna L.; Blacken, Robyn A.; Habener, Joel F.

2005-01-01

Cellular replacement therapy holds promise for the treatment of diabetes mellitus but donor tissue is severely limited. Therefore, we investigated whether insulin-secreting cells could be differentiated in vitro from a monolayer of cells expanded from human donor pancreatic islets. We describe a three-step culture protocol that allows for the efficient generation of insulin-producing cell clusters from in vitro expanded, hormone-negative cells. These clusters express insulin at levels of up to 34% that of average freshly isolated human islets and secrete C-peptide upon membrane depolarization. They also contain cells expressing the other major islet hormones (glucagon, somatostatin, and pancreatic polypeptide). The source of the newly differentiated endocrine cells could either be indigenous stem/progenitor cells or the proliferation-associated dedifferentiation and subsequent redifferentiation of mature endocrine cells. The in vitro generated cell clusters may be efficacious in providing islet-like tissue for transplantation into diabetic recipients

Ancestral genomic duplication of the insulin gene in tilapia: An analysis of possible implications for clinical islet xenotransplantation using donor islets from transgenic tilapia expressing a humanized insulin gene.

Science.gov (United States)

Hrytsenko, Olga; Pohajdak, Bill; Wright, James R

2016-07-03

Tilapia, a teleost fish, have multiple large anatomically discrete islets which are easy to harvest, and when transplanted into diabetic murine recipients, provide normoglycemia and mammalian-like glucose tolerance profiles. Tilapia insulin differs structurally from human insulin which could preclude their use as islet donors for xenotransplantation. Therefore, we produced transgenic tilapia with islets expressing a humanized insulin gene. It is now known that fish genomes may possess an ancestral duplication and so tilapia may have a second insulin gene. Therefore, we cloned, sequenced, and characterized the tilapia insulin 2 transcript and found that its expression is negligible in islets, is not islet-specific, and would not likely need to be silenced in our transgenic fish.

From the Cover: Cell-replacement therapy for diabetes: Generating functional insulin-producing tissue from adult human liver cells

Science.gov (United States)

Sapir, Tamar; Shternhall, Keren; Meivar-Levy, Irit; Blumenfeld, Tamar; Cohen, Hamutal; Skutelsky, Ehud; Eventov-Friedman, Smadar; Barshack, Iris; Goldberg, Iris; Pri-Chen, Sarah; Ben-Dor, Lya; Polak-Charcon, Sylvie; Karasik, Avraham; Shimon, Ilan; Mor, Eytan; Ferber, Sarah

2005-05-01

Shortage in tissue availability from cadaver donors and the need for life-long immunosuppression severely restrict the large-scale application of cell-replacement therapy for diabetic patients. This study suggests the potential use of adult human liver as alternate tissue for autologous beta-cell-replacement therapy. By using pancreatic and duodenal homeobox gene 1 (PDX-1) and soluble factors, we induced a comprehensive developmental shift of adult human liver cells into functional insulin-producing cells. PDX-1-treated human liver cells express insulin, store it in defined granules, and secrete the hormone in a glucose-regulated manner. When transplanted under the renal capsule of diabetic, immunodeficient mice, the cells ameliorated hyperglycemia for prolonged periods of time. Inducing developmental redirection of adult liver offers the potential of a cell-replacement therapy for diabetics by allowing the patient to be the donor of his own insulin-producing tissue. pancreas | transdifferentiation

Quality control of insulin radioreceptor assay for human erythrocytes. Effect of ageing of mono-125I-Tyr-A14-insulin preparation

International Nuclear Information System (INIS)

Marttinen, A.; Pasternack, A.; Koivula, T.; Jokela, H.; Lehtinen, M.

1984-01-01

The quality control of insulin radioreceptor assay for human erythrocytes is based on the storage of erythrocyte preparations in Hepes buffer of pH 8.0, containing 10 g/l of albumin and 20 mmol/l of glucose. The change of erythrocytes into spherocytes and crenated cells reduces the apparent number of insulin receptors in a relatively constant way by less than 8% a week after 10 days of storage. At the same time the dissociation constants of the insulin-receptor complex increase rapidly. Thus the use of a preparation must be limited to controlling the determination of the insulin binding sites of erythrocytes, and not to the measurement of the affinities of the receptors. When mono- 125 I-Tyr-A14-insulin gets old, a slow decrease in the insulin binding sites can be measured, but the dissociation constants of the insulin receptor complex are not affected. (author)

Short-acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus.

Science.gov (United States)

Fullerton, Birgit; Siebenhofer, Andrea; Jeitler, Klaus; Horvath, Karl; Semlitsch, Thomas; Berghold, Andrea; Plank, Johannes; Pieber, Thomas R; Gerlach, Ferdinand M

2016-06-30

Short-acting insulin analogue use for people with diabetes is still controversial, as reflected in many scientific debates. To assess the effects of short-acting insulin analogues versus regular human insulin in adults with type 1 diabetes. We carried out the electronic searches through Ovid simultaneously searching the following databases: Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R) (1946 to 14 April 2015), EMBASE (1988 to 2015, week 15), the Cochrane Central Register of Controlled Trials (CENTRAL; March 2015), ClinicalTrials.gov and the European (EU) Clinical Trials register (both March 2015). We included all randomised controlled trials with an intervention duration of at least 24 weeks that compared short-acting insulin analogues with regular human insulins in the treatment of adults with type 1 diabetes who were not pregnant. Two review authors independently extracted data and assessed trials for risk of bias, and resolved differences by consensus. We graded overall study quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) instrument. We used random-effects models for the main analyses and presented the results as odds ratios (OR) with 95% confidence intervals (CI) for dichotomous outcomes. We identified nine trials that fulfilled the inclusion criteria including 2693 participants. The duration of interventions ranged from 24 to 52 weeks with a mean of about 37 weeks. The participants showed some diversity, mainly with regard to diabetes duration and inclusion/exclusion criteria. The majority of the trials were carried out in the 1990s and participants were recruited from Europe, North America, Africa and Asia. None of the trials was carried out in a blinded manner so that the risk of performance bias, especially for subjective outcomes such as hypoglycaemia, was present in all of the trials. Furthermore, several trials showed inconsistencies in

A human model of dietary saturated fatty acid induced insulin resistance.

Science.gov (United States)

Koska, Juraj; Ozias, Marlies K; Deer, James; Kurtz, Julie; Salbe, Arline D; Harman, S Mitchell; Reaven, Peter D

2016-11-01

Increased consumption of high-fat diets is associated with the development of insulin resistance and type 2 diabetes. Current models to study the mechanisms of high-fat diet-induced IR in humans are limited by their long duration or low efficacy. In the present study we developed and characterized an acute dietary model of saturated fatty acid-enriched diet induced insulin resistance. High caloric diets enriched with saturated fatty acids (SFA) or carbohydrates (CARB) were evaluated in subjects with normal and impaired glucose tolerance (NGT or IGT). Both diets were compared to a standard eucaloric American Heart Association (AHA) control diet in a series of crossover studies. Whole body insulin resistance was estimated as steady state plasma glucose (SSPG) concentrations during the last 30min of a 3-h insulin suppression test. SSPG was increased after a 24-h SFA diet (by 83±74% vs. control, n=38) in the entire cohort, which was comprised of participants with NGT (92±82%, n=22) or IGT (65±55%, n=16) (all pinsulin resistance in both NGT and IGT subjects. Insulin resistance persisted overnight after the last SFA meal and was attenuated by one day of a healthy diet. This model offers opportunities for identifying early mechanisms and potential treatments of dietary saturated fat induced insulin resistance. Published by Elsevier Inc.

Monoclonal antibody to the type I insulin-like growth factor (IGF-I) receptor blocks IGF-I receptor-mediated DNA synthesis: clarification of the mitogenic mechanisms of IGF-I and insulin in human skin fibroblasts

International Nuclear Information System (INIS)

Flier, J.S.; Usher, P.; Moses, A.C.

1986-01-01

Insulin and insulin-like growth factor type I (IGF-I) stimulate an overlapping spectrum of biological responses in human skin fibroblasts. Although insulin and IGF-I are known to stimulate the incorporation of [ 3 H]thymidine into DNA in these cells, the identify of the receptor(s) that mediates this effect has not been fully clarified. The mouse anti-human IGF-I receptor antibody αIR-3 binds with specificity to IGF-I but not to insulin receptors in human placental membranes; it also specifically inhibits the binding of 125 I-labeled IGF-I but not 125 I-labeled insulin to suspensions of human skin fibroblasts in a dose-dependent manner. αIR-3 competitively inhibits IGF-I-mediated stimulation of [ 3 H]thymidine incorporation into DNA. This inhibition is dependent on the concentration of αIR-3 and in the presence of a fixed antibody concentration can be partially overcome by high concentrations of IGF-I. In contrast, at concentrations of 3 H]thymidine incorporation is not inhibited by αIR-3. However, the incremental effects of higher concentrations (> 1 μg/ml) of insulin on [ 3 H]thymidine incorporation are inhibited by αIR-3. αIR-3 is a highly specific antagonist of IGF-I receptor-mediated mitogenesis in human skin fibroblasts. By using this antibody, it is shown directly that insulin can act through the IGF-I receptor to stimulate DNA synthesis but can also activate this effect through the insulin receptor itself

Resveratrol ameliorates the chemical and microbial induction of inflammation and insulin resistance in human placenta, adipose tissue and skeletal muscle.

Science.gov (United States)

Tran, Ha T; Liong, Stella; Lim, Ratana; Barker, Gillian; Lappas, Martha

2017-01-01

Gestational diabetes mellitus (GDM), which complicates up to 20% of all pregnancies, is associated with low-grade maternal inflammation and peripheral insulin resistance. Sterile inflammation and infection are key mediators of this inflammation and peripheral insulin resistance. Resveratrol, a stilbene-type phytophenol, has been implicated to exert beneficial properties including potent anti-inflammatory and antidiabetic effects in non-pregnant humans and experimental animal models of GDM. However, studies showing the effects of resveratrol on inflammation and insulin resistance associated with GDM in human tissues have been limited. In this study, human placenta, adipose (omental and subcutaneous) tissue and skeletal muscle were stimulated with pro-inflammatory cytokines TNF-α and IL-1β, the bacterial product lipopolysaccharide (LPS) and the synthetic viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) to induce a GDM-like model. Treatment with resveratrol significantly reduced the expression and secretion of pro-inflammatory cytokines IL-6, IL-1α, IL-1β and pro-inflammatory chemokines IL-8 and MCP-1 in human placenta and omental and subcutaneous adipose tissue. Resveratrol also significantly restored the defects in the insulin signalling pathway and glucose uptake induced by TNF-α, LPS and poly(I:C). Collectively, these findings suggest that resveratrol reduces inflammation and insulin resistance induced by chemical and microbial products. Resveratrol may be a useful preventative therapeutic for pregnancies complicated by inflammation and insulin resistance, like GDM.

Effects of inhibition of interleukin-6 signalling on insulin sensitivity and lipoprotein (a levels in human subjects with rheumatoid diseases.

Directory of Open Access Journals (Sweden)

Olaf Schultz

2010-12-01

Full Text Available Interleukin-6 (IL-6 is a pro-inflammatory cytokine that has been found to be increased in type 2 diabetic subjects. However, it still remains unclear if these elevated IL-6 levels are co-incidental or if this cytokine is causally related to the development of insulin resistance and type 2 diabetes in humans. Therefore, in the present study we examined insulin sensitivity, serum adipokine levels and lipid parameters in human subjects before and after treatment with the IL-6 receptor antibody Tocilizumab.11 non-diabetic patients with rheumatoid disease were included in the study. HOMA-IR was calculated and serum levels for leptin, adiponectin, triglycerides, LDL-cholesterol, HDL-cholesterol and lipoprotein (a (Lp (a were measured before as well as one and three months after Tocilizumab treatment. The HOMA index for insulin resistance decreased significantly. While leptin concentrations were not altered by inhibition of IL-6 signalling, adiponectin concentrations significantly increased. Thus the leptin to adiponectin ratio, a novel marker for insulin resistance, exhibited a significant decrease. Serum triglycerides, LDL-cholesterol and HDL-cholesterol tended to be increased whereas Lp (a levels significantly decreased.Inhibition of IL-6 signalling improves insulin sensitivity in humans with immunological disease suggesting that elevated IL-6 levels in type 2 diabetic subjects might be causally involved in the pathogenesis of insulin resistance. Furthermore, our data indicate that inhibition of IL-6 signalling decreases Lp (a serum levels, which might reduce the cardiovascular risk of human subjects.

Production of functional human insulin-like growth factor binding proteins (IGFBPs) using recombinant expression in HEK293 cells.

Science.gov (United States)

Wanscher, Anne Sofie Molsted; Williamson, Michael; Ebersole, Tasja Wainani; Streicher, Werner; Wikström, Mats; Cazzamali, Giuseppe

2015-04-01

Insulin-like growth factor binding proteins (IGFBPs) display many functions in humans including regulation of the insulin-like growth factor (IGF) signaling pathway. The various roles of human IGFBPs make them attractive protein candidates in drug discovery. Structural and functional knowledge on human proteins with therapeutic relevance is needed to design and process the next generation of protein therapeutics. In order to conduct structural and functional investigations large quantities of recombinant proteins are needed. However, finding a suitable recombinant production system for proteins such as full-length human IGFBPs, still remains a challenge. Here we present a mammalian HEK293 expression method suitable for over-expression of secretory full-length human IGFBP-1 to -7. Protein purification of full-length human IGFBP-1, -2, -3 and -5 was conducted using a two-step chromatography procedure and the final protein yields were between 1 and 12mg protein per liter culture media. The recombinant IGFBPs contained PTMs and exhibited high-affinity interactions with their natural ligands IGF-1 and IGF-2. Copyright © 2014 Elsevier Inc. All rights reserved.

Production of functional human insulin-like growth factor binding proteins (IGFBPs) using recombinant expression in HEK293 cells

DEFF Research Database (Denmark)

Wanscher, Anne Sofie Molsted; Williamson, Michael; Ebersole, Tasja Wainani

2015-01-01

on human proteins with therapeutic relevance is needed to design and process the next generation of protein therapeutics. In order to conduct structural and functional investigations large quantities of recombinant proteins are needed. However, finding a suitable recombinant production system for proteins...... and the final protein yields were between 1 and 12mg protein per liter culture media. The recombinant IGFBPs contained PTMs and exhibited high-affinity interactions with their natural ligands IGF-1 and IGF-2.......Insulin-like growth factor binding proteins (IGFBPs) display many functions in humans including regulation of the insulin-like growth factor (IGF) signaling pathway. The various roles of human IGFBPs make them attractive protein candidates in drug discovery. Structural and functional knowledge...

Reduced malonyl-CoA content in recovery from exercise correlates with improved insulin-stimulated glucose uptake in human skeletal muscle

DEFF Research Database (Denmark)

Frøsig, Christian; Roepstorff, Carsten; Brandt, Nina

2009-01-01

This study evaluated whether improved insulin-stimulated glucose uptake in recovery from acute exercise coincides with reduced malonyl-CoA (MCoA) content in human muscle. Furthermore, we investigated whether a high-fat diet [65 energy-% (Fat)] would alter the content of MCoA and insulin action...... to be compromised, although to a minor extent, by the Fat diet. Collectively, this study indicates that reduced muscle MCoA content in recovery from exercise may be part of the adaptive response leading to improved insulin action on glucose uptake after exercise in human muscle....

Quality control of insulin radioreceptor assay for human erythrocytes. Effect of ageing of mono-/sup 125/I-Tyr-A14-insulin preparation

Energy Technology Data Exchange (ETDEWEB)

Marttinen, A; Pasternack, A [Tampere Univ. (Finland). Dept. of Clinical Sciences; Koivula, T; Jokela, H; Lehtinen, M [Tampere Univ. Central Hospital (Finland). Dept. of Clinical Chemistry

1984-09-01

The quality control of insulin radioreceptor assay for human erythrocytes is based on the storage of erythrocyte preparations in Hepes buffer of pH 8.0, containing 10 g/l of albumin and 20 mmol/l of glucose. The change of erythrocytes into spherocytes and crenated cells reduces the apparent number of insulin receptors in a relatively constant way by less than 8% a week after 10 days of storage. At the same time the dissociation constants of the insulin-receptor complex increase rapidly. Thus the use of a preparation must be limited to controlling the determination of the insulin binding sites of erythrocytes, and not to the measurement of the affinities of the receptors. When mono-/sup 125/I-Tyr-A14-insulin gets old, a slow decrease in the insulin binding sites can be measured, but the dissociation constants of the insulin receptor complex are not affected.

Determination of human insulin in dog plasma by a selective liquid chromatography-tandem mass spectrometry method: Application to a pharmacokinetic study.

Science.gov (United States)

Dong, Shiqi; Zeng, Yong; Wei, Guangli; Si, Duanyun; Liu, Changxiao

2018-03-01

A simple, sensitive and selective LC-MS/MS method for quantitative analysis of human insulin was developed and validated in dog plasma. Insulin glargine was used as the internal standard. After a simple step of solid-phase extraction, the chromatographic separation of human insulin was achieved by using InertSustain Bio C18 column with a mobile phase of acetonitrile containing 1% formic acid (A)-water containing 1% formic acid (B). The detection was performed by positive ion electrospray ionization in multiple-reaction monitoring (MRM) mode. Good linearity was observed in the concentration range of 1-1000 μIU/mL (r 2  > 0.99), and the lower limit of quantification was 1 μIU/mL (equal to 38.46 pg/mL). The intra- and inter-day precision (expressed as relative standard deviation, RSD) of human insulin were ≤12.1% and ≤13.0%, respectively, and the accuracy (expressed as relative error, RE) was in the range of -7.23-11.9%. The recovery and matrix effect were both within acceptable limits. This method was successfully applied for the pharmacokinetic study of human insulin in dogs after subcutaneous administration. Copyright © 2018 Elsevier B.V. All rights reserved.

Cephalic phase secretion of insulin and other enteropancreatic hormones in humans

DEFF Research Database (Denmark)

Veedfald, Simon; Plamboeck, Astrid; Deacon, Carolyn F

2016-01-01

Enteropancreatic hormone secretion is thought to include a cephalic phase, but the evidence in humans is ambiguous. We studied vagally induced gut hormone responses with and without muscarinic blockade in 10 glucose-clamped healthy men (age: 24.5 ± 0.6 yr, means ± SE; body mass index: 24.0 ± 0.5 kg...... and abolished the MSF response. Neither insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP), nor glucagon-like peptide-1 (GLP-1) levels changed in response to MSF or atropine. Glucagon and ghrelin levels were markedly attenuated by atropine prior to and during the clamp: at t = 105 min...... and 3.7 ± 21 pg/ml (means ± SE), P phase response was absent for insulin, glucagon, GLP-1, GIP, and ghrelin....

The Investigation of ADAMTS16 in Insulin-Induced Human Chondrosarcoma Cells.

Science.gov (United States)

Cakmak, Ozlem; Comertoglu, Ismail; Firat, Ridvan; Erdemli, Haci Kemal; Kursunlu, S Fatih; Akyol, Sumeyya; Ugurcu, Veli; Altuntas, Aynur; Adam, Bahattin; Demircan, Kadir

2015-08-01

A disintegrin-like metalloproteinase with thrombospondin motifs (ADAMTS) is a group of proteins that have enzymatic activity secreted by cells to the outside extracellular matrix. Insulin induces proteoglycan biosynthesis in chondrosarcoma chondrocytes. The purpose of the present in vitro study is to assess the time course effects of insulin on ADAMTS16 expression in OUMS-27 (human chondrosarcoma) cell line to examine whether insulin regulates ADAMTS16 expression as well as proteoglycan biosynthesis with multifaceted properties or not. Chondrosarcoma cells were cultured in Dulbecco's modified Eagle's medium having either 10 μg/mL insulin or not. While the experiment was going on, the medium containing insulin had been changed every other day. Cells were harvested at 1st, 3rd, 7th, and 11th days; subsequently, RNA and proteins were isolated in every experimental group according to their time interval. RNA expression of ADAMTS was estimated by quantitative real-time polymerase chain reaction (qRT-PCR) by using primers. Immunoreactive protein levels were encountered by the western blot protein detection technique by using proper anti-ADAMTS16 antibodies. ADAMTS16 mRNA expression level of chondrosarcoma cells was found to be insignificantly decreased in chondrosarcoma cells induced by insulin detected by the qRT-PCR instrument. On the other hand, there was a gradual decrease in immune-reactant ADAMTS16 protein amount by the time course in insulin-treated cell groups when compared with control cells. It has been suggested that insulin might possibly regulate ADAMTS16 levels/activities in OUMS-27 chondrosarcoma cells taking a role in extracellular matrix turnover.

Dual effect of insulin resistance and cadmium on human granulosa cells - In vitro study

Energy Technology Data Exchange (ETDEWEB)

Belani, Muskaan, E-mail: muskaanbelani@gmail.com [Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390 002, Gujarat, India. (India); Shah, Preeti, E-mail: preeti.shah@novaivifertility.com [Nova IVI Fertility, Behind Xavier' s Ladies Hostel, 108, Swastik Society Rd., Navrangpura, Ahmedabad 390009, Gujarat, India. (India); Banker, Manish, E-mail: manish.banker@novaivifertility.com [Nova IVI Fertility, Behind Xavier' s Ladies Hostel, 108, Swastik Society Rd., Navrangpura, Ahmedabad 390009, Gujarat, India. (India); Gupta, Sarita, E-mail: saritagupta9@gmail.com [Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390 002, Gujarat, India. (India)

2016-12-15

Combined exposure of cadmium (Cd) and insulin resistance (IR) might be responsible for subfertility. In the present study, we investigated the effects of Cd in vitro in IR human granulosa cells. Isolated human granulosa cells from control and polycystic ovary syndrome (PCOS) follicular fluid samples were confirmed for IR by decrease in protein expression of insulin receptor-β. Control and IR human granulosa cells were then incubated with or without 32 μM Cd. The combined effect of IR with 32 μM Cd in granulosa cells demonstrated significant decrease in expression of StAR, CYP11A1, CYP19A1, 17β-HSD, 3β-HSD, FSH-R and LH-R. Decrease was also observed in progesterone and estradiol concentrations as compared to control. Additionally, increase in protein expression of cleaved PARP-F2, active caspase-3 and a positive staining for Annexin V and PI indicated apoptosis as the mode of increased cell death ultimately leading to decreased steroidogenesis, as observed through the combined exposure. Taken together the results suggest decrease in steroidogenesis ultimately leading to abnormal development of the follicle thus compromising fertility at the level of preconception. - Highlights: • Protein expression of INSR-β in granulosa cells to differentiate PCOS-IR and NIR • Cd and IR together decrease steroidogenesis in human granulosa cells in vitro. • Cd and IR increase human granulosa cell death by increase in apoptosis. • Environment and life style are set to hamper pregnancies at preconception level.

Dual effect of insulin resistance and cadmium on human granulosa cells - In vitro study

International Nuclear Information System (INIS)

Belani, Muskaan; Shah, Preeti; Banker, Manish; Gupta, Sarita

2016-01-01

Combined exposure of cadmium (Cd) and insulin resistance (IR) might be responsible for subfertility. In the present study, we investigated the effects of Cd in vitro in IR human granulosa cells. Isolated human granulosa cells from control and polycystic ovary syndrome (PCOS) follicular fluid samples were confirmed for IR by decrease in protein expression of insulin receptor-β. Control and IR human granulosa cells were then incubated with or without 32 μM Cd. The combined effect of IR with 32 μM Cd in granulosa cells demonstrated significant decrease in expression of StAR, CYP11A1, CYP19A1, 17β-HSD, 3β-HSD, FSH-R and LH-R. Decrease was also observed in progesterone and estradiol concentrations as compared to control. Additionally, increase in protein expression of cleaved PARP-F2, active caspase-3 and a positive staining for Annexin V and PI indicated apoptosis as the mode of increased cell death ultimately leading to decreased steroidogenesis, as observed through the combined exposure. Taken together the results suggest decrease in steroidogenesis ultimately leading to abnormal development of the follicle thus compromising fertility at the level of preconception. - Highlights: • Protein expression of INSR-β in granulosa cells to differentiate PCOS-IR and NIR • Cd and IR together decrease steroidogenesis in human granulosa cells in vitro. • Cd and IR increase human granulosa cell death by increase in apoptosis. • Environment and life style are set to hamper pregnancies at preconception level.

Zinc stimulates glucose oxidation and glycemic control by modulating the insulin signaling pathway in human and mouse skeletal muscle cell lines.

Science.gov (United States)

Norouzi, Shaghayegh; Adulcikas, John; Sohal, Sukhwinder Singh; Myers, Stephen

2018-01-01

Zinc is a metal ion that is an essential cell signaling molecule. Highlighting this, zinc is an insulin mimetic, activating cellular pathways that regulate cellular homeostasis and physiological responses. Previous studies have linked dysfunctional zinc signaling with several disease states including cancer, obesity, cardiovascular disease and type 2 diabetes. The present study evaluated the insulin-like effects of zinc on cell signaling molecules including tyrosine, PRSA40, Akt, ERK1/2, SHP-2, GSK-3β and p38, and glucose oxidation in human and mouse skeletal muscle cells. Insulin and zinc independently led to the phosphorylation of these proteins over a 60-minute time course in both mouse and human skeletal muscle cells. Similarly, utilizing a protein array we identified that zinc could active the phosphorylation of p38, ERK1/2 and GSK-3B in human and ERK1/2 and GSK-3B in mouse skeletal muscle cells. Glucose oxidation assays were performed on skeletal muscle cells treated with insulin, zinc, or a combination of both and resulted in a significant induction of glucose consumption in mouse (pzinc alone. Insulin, as expected, increased glucose oxidation in mouse (pzinc and insulin did not augment glucose consumption in these cells. Zinc acts as an insulin mimetic, activating key molecules implicated in cell signaling to maintain glucose homeostasis in mouse and human skeletal muscle cells. Zinc is an important metal ion implicated in several biological processes. The role of zinc as an insulin memetic in activating key signaling molecules involved in glucose homeostasis could provide opportunities to utilize this ion therapeutically in treating disorders associated with dysfunctional zinc signaling.

Preparative isolation by high performance liquid chromatography of human insulin B chain produced in escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Cruz, N.; Antonio, S.; De Anda, R.; Gosset, G.; Bolivar, F. (Centro de Investigacion sobre Ingenieria Genetica y Biotecnologia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 510-3 Cuernavaca, Mor. 62271 (MX))

1990-01-01

This paper reports on a simple method developed for the analytical and preparative purification of human insulin B chain from recombinant origin. Three solvent systems: acetonitrile, isopropanol and methanol, were studied to determine their capacity to resolve the insulin B chain from a mixture of cyanogen bromide generated bacterial peptides. Using a {mu}Bondapak C18 column, it was possible to resolve the insulin B chain in all three systems. On a preparative scale, using a PrePak 500 C18 column with the isopropanol system, it was possible to purify insulin B chain and to obtain a 95% protein recovery.

Effect of 5'-flanking sequence deletions on expression of the human insulin gene in transgenic mice

DEFF Research Database (Denmark)

Fromont-Racine, M; Bucchini, D; Madsen, O

1990-01-01

Expression of the human insulin gene was examined in transgenic mouse lines carrying the gene with various lengths of DNA sequences 5' to the transcription start site (+1). Expression of the transgene was demonstrated by 1) the presence of human C-peptide in urine, 2) the presence of specific...... of the transgene was observed in cell types other than beta-islet cells....

Characterization of Insulin-Immunoreactive Cells and Endocrine Cells Within the Duct System of the Adult Human Pancreas.

Science.gov (United States)

Li, Rong; Zhang, Xiaoxi; Yu, Lan; Zou, Xia; Zhao, Hailu

2016-01-01

The adult pancreatic duct system accommodates endocrine cells that have the potential to produce insulin. Here we report the characterization and distribution of insulin-immunoreactive cells and endocrine cells within the ductal units of adult human pancreas. Sequential pancreas sections from 12 nondiabetic adults were stained with biomarkers of ductal epithelial cells (cytokeratin 19), acinar cells (amylase), endocrine cells (chromogranin A; neuron-specific enolase), islet hormones (insulin, glucagon, somatostatin, pancreatic polypeptide), cell proliferation (Ki-67), and neogenesis (CD29). The number of islet hormone-immunoreactive cells increased from large ducts to the terminal branches. The insulin-producing cells outnumbered endocrine cells reactive for glucagon, somatostatin, or pancreatic polypeptide. The proportions of insulin-immunoreactive count compared with local islets (100% as a baseline) were 1.5% for the main ducts, 7.2% for interlobular ducts, 24.8% for intralobular ducts, 67.9% for intercalated ducts, and 348.9% for centroacinar cells. Both Ki-67- and CD29-labeled cells were predominantly localized in the terminal branches around the islets. The terminal branches also showed cells coexpressing islet hormones and cytokeratin 19. The adult human pancreatic ducts showed islet hormone-producing cells. The insulin-reactive cells predominantly localized in terminal branches where they may retain potential capability for β-cell neogenesis.

Human and rodent muscle Na(+)-K(+)-ATPase in diabetes related to insulin, starvation, and training

DEFF Research Database (Denmark)

Schmidt, T A; Hasselbalch, S; Farrell, P A

1994-01-01

cerebral cortex Na(+)-K(+)-ATPase concentration as a result of diabetes, semistarvation, or insulin treatment. In human subjects, Na(+)-K(+)-ATPase concentration in vastus lateralis muscle biopsies was 17 and 22% greater (P dependent diabetes...... mellitus (n = 24) and insulin-dependent diabetes mellitus (n = 7) than in control subjects (n = 8). A positive linear correlation between muscle Na(+)-K(+)-ATPase and plasma insulin concentrations was observed (r = 0.50, P = 0.006; n = 29). Thus, insulin seems a regulator of muscle Na......(+)-K(+)-ATPase concentration, reduction of muscle Na(+)-K(+)-ATPase concentration with untreated diabetes bears similarities with undernourishment, and physical conditioning may ameliorate the muscle Na(+)-K(+)-ATPase concentration decrease induced by diabetes....

Calcification of human vascular smooth muscle cells: associations with osteoprotegerin expression and acceleration by high-dose insulin

DEFF Research Database (Denmark)

Olesen, Ping; Knudsen, Kirsten Quyen Nguyen; Wogensen, Lise

2007-01-01

Arterial medial calcifications occur often in diabetic individuals as part of the diabetic macroangiopathy. The pathogenesis is unknown, but the presence of calcifications predicts risk of cardiovascular events. We examined the effects of insulin on calcifying smooth muscle cells in vitro...... and measured the expression of the bone-related molecule osteoprotegerin (OPG). Human vascular smooth muscle cells (VSMCs) were grown from aorta from kidney donors. Induction of calcification was performed with beta-glycerophosphate. The influence of insulin (200 microU/ml or 1,000 microU/ml) on calcification...... calcification in human smooth muscle cells from a series of donors after variable time in culture. Decreased OPG amounts were observed from the cells during the accelerated calcification phase. High dose of insulin (1,000 microU/ml) accelerated the calcification, whereas lower concentrations (200 microU/ml) did...

Interleukin-1β inhibits insulin signaling and prevents insulin-stimulated system A amino acid transport in primary human trophoblasts.

Science.gov (United States)

Aye, Irving L M H; Jansson, Thomas; Powell, Theresa L

2013-12-05

Interleukin-1β (IL-1β) promotes insulin resistance in tissues such as liver and skeletal muscle; however the influence of IL-1β on placental insulin signaling is unknown. We recently reported increased IL-1β protein expression in placentas of obese mothers, which could contribute to insulin resistance. In this study, we tested the hypothesis that IL-1β inhibits insulin signaling and prevents insulin-stimulated amino acid transport in cultured primary human trophoblast (PHT) cells. Cultured trophoblasts isolated from term placentas were treated with physiological concentrations of IL-1β (10pg/ml) for 24h. IL-1β increased the phosphorylation of insulin receptor substrate-1 (IRS-1) at Ser307 (inhibitory) and decreased total IRS-1 protein abundance but did not affect insulin receptor β expression. Furthermore, IL-1β inhibited insulin-stimulated phosphorylation of IRS-1 (Tyr612, activation site) and Akt (Thr308) and prevented insulin-stimulated increase in PI3K/p85 and Grb2 protein expression. IL-1β alone stimulated cRaf (Ser338), MEK (Ser221) and Erk1/2 (Thr202/Tyr204) phosphorylation. The inflammatory pathways nuclear factor kappa B and c-Jun N-terminal kinase, which are involved in insulin resistance, were also activated by IL-1β treatment. Moreover, IL-1β inhibited insulin-stimulated System A, but not System L amino acid uptake, indicating functional impairment of insulin signaling. In conclusion, IL-1β inhibited the insulin signaling pathway by inhibiting IRS-1 signaling and prevented insulin-stimulated System A transport, thereby promoting insulin resistance in cultured PHT cells. These findings indicate that conditions which lead to increased systemic maternal or placental IL-1β levels may attenuate the effects of maternal insulin on placental function and consequently fetal growth. Published by Elsevier Ireland Ltd.

Differential roles of MAPK-Erk1/2 and MAPK-p38 in insulin or insulin-like growth factor-I (IGF-I) signaling pathways for progesterone production in human ovarian cells.

Science.gov (United States)

Seto-Young, D; Avtanski, D; Varadinova, M; Park, A; Suwandhi, P; Leiser, A; Parikh, G; Poretsky, L

2011-06-01

Insulin and insulin like-growth factor-I (IGF-I) participate in the regulation of ovarian steroidogenesis. In insulin resistant states ovaries remain sensitive to insulin because insulin can activate alternative signaling pathways, such as phosphatidylinositol-3-kinase (PI-3 kinase) and mitogen-activated protein-kinase (MAPK) pathways, as well as insulin receptors and type 1 IGF receptors. We investigated the roles of MAPK-Erk1/2 and MAPK-p38 in insulin and IGF-I signaling pathways for progesterone production in human ovarian cells. Human ovarian cells were cultured in tissue culture medium in the presence of varying concentrations of insulin or IGF-I, with or without PD98059, a specific MAPK-Erk1/2 inhibitor, with or without SB203580, a specific MAPK-p38 inhibitor or with or without a specific PI-3-kinase inhibitor LY294002. Progesterone concentrations were measured using radioimmunoassay. PD98059 alone stimulated progesterone production in a dose-dependent manner by up to 65% (pprogesterone production by 13-18% (pprogesterone production by 17-20% (pprogesterone production by 20-30% (pprogesterone production by 40-60% (pprogesterone synthesis while SB203580 abolished insulin-induced progesterone production. Either PD98059 or SB203580 abolished IGF-I-induced progesterone production. Both MAPK-Erk1/2 and MAPK-p38 participate in IGF-I-induced signaling pathways for progesterone production, while insulin-induced progesterone production requires MAPK-p38, but not MAPK-Erk1/2. These studies provide further evidence for divergence of insulin and IGF-I signaling pathways for human ovarian cell steroidogenesis. © Georg Thieme Verlag KG Stuttgart · New York.

1H NMR spectrum of the native human insulin monomer. Evidence for conformational differences between the monomer and aggregated forms.

Science.gov (United States)

Roy, M; Lee, R W; Brange, J; Dunn, M F

1990-04-05

The effects of high dilution on the 1H Fourier transform NMR spectrum of native human insulin at pH* 8.0 and 9.3 have been examined at 500 MHz resolution. The dependence of the spectrum on concentration and comparison with the spectrum of a biologically highly potent monomeric insulin mutant (SerB9----Asp) establish that at 36 microM (pH* 9.3) or 18 microM (pH* 8) and no added buffer or salts, human insulin is monomeric. Under these conditions of dilution, ionic strength, and pH*, human insulin and the SerB9----Asp mutant exhibit nearly identical 1H NMR spectra. At higher concentrations (i.e. greater than 36 microM to 0.91 mM), native human insulin dimerizes, and this aggregation causes a change in insulin conformation. Although there are many changes in the spectrum, the TyrB26 ring H3,5 proton signals located at 6.63 ppm and the methyl signal located at 0.105 ppm (characteristics of monomeric insulin) are particularly distinct signatures of the conformation change that accompanies dimerization. Magnetization transfer experiments show that the 0.105 ppm methyl signal shifts downfield to a new position at 0.45 ppm. We conclude that the 0.105 ppm methyl signal is due to a conformation in which a Leu methyl group is centered over and in van der Waals contact with the ring of an aromatic side chain. Dimerization causes a conformation change that alters this interaction, thereby causing the downfield shift. Nuclear Overhauser studies indicate that the methyl group involved is located within a cluster of aromatic side chains and that the closest ring-methyl group interaction is with the ring of PheB24.

Development of a transgenic mouse model to study the immunogenicity of recombinant human insulin

NARCIS (Netherlands)

Torosantucci, Riccardo; Brinks, Vera; Kijanka, Grzegorz; Halim, Liem Andhyk; Sauerborn, Melody; Schellekens, Huub; Jiskoot, Wim

2014-01-01

Mouse models are commonly used to assess the immunogenicity of therapeutic proteins and to investigate the immunological processes leading to antidrug antibodies. The aim of this work was to develop a transgenic (TG) Balb/c mouse model for evaluating the immunogenicity of recombinant human insulin

Effects of the beta-carbolines, harmane and pinoline, on insulin secretion from isolated human islets of Langerhans.

Science.gov (United States)

Cooper, E Jane; Hudson, Alan L; Parker, Christine A; Morgan, Noel G

2003-12-15

It is well known that certain imidazoline compounds can stimulate insulin secretion and this has been attributed to the activation of imidazoline I(3) binding sites in the pancreatic beta-cell. Recently, it has been proposed that beta-carbolines may be endogenous ligands having activity at imidazoline sites and we have, therefore, studied the effects of beta-carbolines on insulin secretion. The beta-carbolines harmane, norharmane and pinoline increased insulin secretion two- to threefold from isolated human islets of Langerhans. The effects of harmane and pinoline were dose-dependent (EC(50): 5 and 25 microM, respectively) and these agents also blocked the inhibitory effects of the potassium channel agonist, diazoxide, on glucose-induced insulin release. Stimulation of insulin secretion by harmane was glucose-dependent but, unlike the imidazoline I(3) receptor agonist efaroxan, it increased the rate of insulin release beyond that elicited by 20 mM glucose (20 mM glucose alone: 253+/-34% vs. basal; 20 mM glucose plus 100 microM harmane: 327+/-15%; P<0.01). Stimulation of insulin secretion by harmane was attenuated by the imidazoline I(3) receptor antagonist KU14R (2 (2-ethyl 2,3-dihydro-2-benzofuranyl)-2-imidazole) and was reduced when islets were treated with efaroxan for 18 h, prior to the addition of harmane. The results reveal that beta-carbolines can potentiate the rate of insulin secretion from human islets and suggest that these agents may be useful prototypes for the development of novel insulin secretagogues.

Insulin and the PI3K/AKT Signaling Pathway Regulate Ribonuclease 7 Expression in the Human Urinary Tract

Science.gov (United States)

Eichler, Tad; Becknell, Brian; Easterling, Robert S.; Ingraham, Susan E.; Cohen, Daniel M.; Schwaderer, Andrew; Hains, David S.; Li, Birong; Cohen, Ariel; Metheny, Jackie; Trindandapani, Susheela; Spencer, John David

2017-01-01

Diabetes mellitus is a systemic disease associated with a deficiency of insulin production or action. Diabetic patients have an increased susceptibility to infection with the urinary tract being the most common site of infection. Recent studies suggest that Ribonuclease 7 (RNase 7) is a potent antimicrobial peptide that plays an important role in protecting the urinary tract from bacterial insult. The impact of diabetes on RNase 7 expression and function are unknown. Here, we investigate the effects of insulin on RNase 7. Using human urine specimens, we measured urinary RNase 7 concentrations in healthy control patients and insulin-deficient type 1 diabetics before and after starting insulin therapy. Compared to controls, diabetic patients had suppressed urinary RNase 7 concentrations, which increased with insulin. Using primary human urothelial cells, we explored the mechanisms by which insulin induces RNase 7. Insulin induces RNase 7 production via the phosphatidylinositide 3-kinase signaling pathway (PI3K/AKT) to shield urothelial cells from uropathogenic E. coli. In contrast, we show that uropathogenic E. coli suppresses PI3K/AKT and RNase 7. Together, these results indicate that insulin and PI3K/AKT signaling are essential for RNase 7 expression. They also suggest that increased infection risks in diabetic patients may be secondary to suppressed RNase 7 production. These data may provide unique insight into novel UTI therapeutic strategies in at risk populations. PMID:27401534

Insulin sensitivity is independent of lipid binding protein trafficking at the plasma membrane in human skeletal muscle

DEFF Research Database (Denmark)

Jordy, Andreas Børsting; Serup, Annette Karen; Karstoft, Kristian

2014-01-01

The aim of the present study was to investigate lipid-induced regulation of lipid binding proteins in human skeletal muscle and the impact hereof on insulin sensitivity. Eleven healthy male subjects underwent a 3-day hyper-caloric and high-fat diet regime. Muscle biopsies were taken before......-regulated by increased fatty acid availability. This suggests a time dependency in the up-regulation of FAT/CD36 and FABPpm protein during high availability of plasma fatty acids. Furthermore, we did not detect FATP1 and FATP4 protein in giant sarcolemmal vesicles obtained from human skeletal muscle. In conclusion......, this study shows that a short-term lipid-load increases mRNA content of key lipid handling proteins in human muscle. However, decreased insulin sensitivity after high-fat diet is not accompanied with relocation of FAT/CD36 or FABPpm protein to the sarcolemma. Finally, FATP1 and FATP4 protein could...

Early detection of degraded A14-125I-insulin in human fibroblasts by the use of high performance liquid chromatography

International Nuclear Information System (INIS)

Stentz, F.B.; Harris, H.L.; Kitabchi, A.E.

1983-01-01

We studied the metabolism of A14-125I-insulin in intact human fibroblasts using high performance liquid chromatography (HPLC) to detect and separate its early degradation products. The high resolving power of HPLC enabled us to separate what has been considered ''intact insulin'' by Sephadex G-50 chromatography or TCA precipitability into two additional peaks that had decreased biochemical properties with respect to immunoprecipitability and receptor binding but not decreased TCA precipitability. We conclude that human fibroblast is capable of metabolizing insulin within 2 min at 37 degrees C into intermediate molecules that can be detected by HPLC but not by TCA precipitability or molecular sieve chromatography

Blood-based biomarkers of age-associated epigenetic changes in human islets associate with insulin secretion and diabetes

DEFF Research Database (Denmark)

Bacos, Karl; Gillberg, Linn; Volkov, Petr

2016-01-01

identified in human islets (for example, KLF14, FHL2, ZNF518B and FAM123C) and some associate with insulin secretion and T2D. DNA methylation correlates with islet expression of multiple genes, including FHL2, ZNF518B, GNPNAT1 and HLTF. Silencing these genes in β-cells alter insulin secretion. Together, we...

miR-375 induces human decidua basalis-derived stromal cells to become insulin-producing cells.

Science.gov (United States)

Shaer, Anahita; Azarpira, Negar; Vahdati, Akbar; Karimi, Mohammad Hosein; Shariati, Mehrdad

2014-09-01

This paper focuses on the development of renewable sources of isletreplacement tissue for the treatment of type I diabetes mellitus. Placental tissue-derived mesenchymal stem cells (MSCs) are a promising source for regenerative medicine due to their plasticity and easy availability. They have the potential to differentiate into insulin-producing cells. miR-375 is a micro RNA that is expressed in the pancreas and involved in islet development. Human placental decidua basalis MSCs (PDB-MSCs) were cultured from full-term human placenta. The immunophenotype of the isolated cells was checked for CD90, CD105, CD44, CD133 and CD34 markers. The MSCs (P3) were chemically transfected with hsa-miR-375. Total RNA was extracted 4 and 6 days after transfection. The expressions of insulin, NGN3, GLUT2, PAX4, PAX6, KIR6.2, NKX6.1, PDX1, and glucagon genes were evaluated using real-time qPCR. On day 6, we tested the potency of the clusters in response to the high glucose challenge and assessed the presence of insulin and NGN3 proteins via immunocytochemistry. Flow cytometry analysis confirmed that more than 90% of the cells were positive for CD90, CD105 and CD44 and negative for CD133 and CD34. Morphological changes were followed from day 2. Cell clusters formed during day 6. Insulin-producing clusters showed a deep red color with DTZ. The expression of pancreatic-specific transcription factors increased remarkably during the four days after transfection and significantly increased on day 7. The clusters were positive for insulin and NGN3 proteins, and C-peptide and insulin secretion increased in response to changes in the glucose concentration (2.8 mM and 16.7 mM). In conclusion, the MSCs could be programmed into functional insulin-producing cells by transfection of miR-375.

WNT5A-JNK regulation of vascular insulin resistance in human obesity.

Science.gov (United States)

Farb, Melissa G; Karki, Shakun; Park, Song-Young; Saggese, Samantha M; Carmine, Brian; Hess, Donald T; Apovian, Caroline; Fetterman, Jessica L; Bretón-Romero, Rosa; Hamburg, Naomi M; Fuster, José J; Zuriaga, María A; Walsh, Kenneth; Gokce, Noyan

2016-12-01

Obesity is associated with the development of vascular insulin resistance; however, pathophysiological mechanisms are poorly understood. We sought to investigate the role of WNT5A-JNK in the regulation of insulin-mediated vasodilator responses in human adipose tissue arterioles prone to endothelial dysfunction. In 43 severely obese (BMI 44±11 kg/m 2 ) and five metabolically normal non-obese (BMI 26±2 kg/m 2 ) subjects, we isolated arterioles from subcutaneous and visceral fat during planned surgeries. Using videomicroscopy, we examined insulin-mediated, endothelium-dependent vasodilator responses and characterized adipose tissue gene and protein expression using real-time polymerase chain reaction and Western blot analyses. Immunofluorescence was used to quantify endothelial nitric oxide synthase (eNOS) phosphorylation. Insulin-mediated vasodilation was markedly impaired in visceral compared to subcutaneous vessels from obese subjects (p<0.001), but preserved in non-obese individuals. Visceral adiposity was associated with increased JNK activation and elevated expression of WNT5A and its non-canonical receptors, which correlated negatively with insulin signaling. Pharmacological JNK antagonism with SP600125 markedly improved insulin-mediated vasodilation by sixfold (p<0.001), while endothelial cells exposed to recombinant WNT5A developed insulin resistance and impaired eNOS phosphorylation (p<0.05). We observed profound vascular insulin resistance in the visceral adipose tissue arterioles of obese subjects that was associated with up-regulated WNT5A-JNK signaling and impaired endothelial eNOS activation. Pharmacological JNK antagonism markedly improved vascular endothelial function, and may represent a potential therapeutic target in obesity-related vascular disease. © The Author(s) 2016.

Roles of circulating WNT-signaling proteins and WNT-inhibitors in human adiposity, insulin resistance, insulin secretion, and inflammation.

Science.gov (United States)

Almario, R U; Karakas, S E

2015-02-01

Wingless-type MMTV integration site family member (WNT) signaling and WNT-inhibitors have been implicated in regulation of adipogenesis, insulin resistance, pancreatic function, and inflammation. Our goal was to determine serum proteins involved in WNT signaling (WNT5 and WISP2) and WNT inhibition (SFRP4 and SFRP5) as they relate to obesity, serum adipokines, insulin resistance, insulin secretion, and inflammation in humans. Study population comprised 57 insulin resistant women with polycystic ovary syndrome (PCOS) and 27 reference women. In a cross-sectional study, blood samples were obtained at fasting, during oral, and frequently sampled intravenous glucose tolerance tests. Serum WNT5, WISP2, and SFRP4 concentrations did not differ between PCOS vs. reference women. Serum WNT5 correlated inversely with weight both in PCOS and reference women, and correlated directly with insulin response during oral glucose tolerance test in PCOS women. Serum WISP2 correlated directly with fatty acid binding protein 4. Serum SFRP5 did not differ between obese (n=32) vs. nonobese (n=25) PCOS women, but reference women had lower SFRP5 (pPCOS groups). Serum SFRP5 correlated inversely with IL-1β, TNF-α, cholesterol, and apoprotein B. These findings demonstrated that WNT5 correlated inversely with adiposity and directly with insulin response, and the WNT-inhibitor SFRP5 may be anti-inflammatory. Better understanding of the role of WNT signaling in obesity, insulin resistance, insulin secretion, lipoprotein metabolism, and inflammation is important for prevention and treatment of metabolic syndrome, diabetes and cardiovascular disease. © Georg Thieme Verlag KG Stuttgart · New York.

Effect of magnesium supplementation on insulin resistance in humans: A systematic review.

Science.gov (United States)

Morais, Jennifer Beatriz Silva; Severo, Juliana Soares; de Alencar, Geórgia Rosa Reis; de Oliveira, Ana Raquel Soares; Cruz, Kyria Jayanne Clímaco; Marreiro, Dilina do Nascimento; Freitas, Betânia de Jesus E Silva de Almendra; de Carvalho, Cecília Maria Resende; Martins, Maria do Carmo de Carvalho E; Frota, Karoline de Macedo Gonçalves

2017-06-01

Recent studies have demonstrated that minerals play a role in glucose metabolism disorders in humans. Magnesium, in particular, is an extensively studied mineral that has been shown to function in the management of hyperglycemia, hyperinsulinemia, and insulin resistance (IR) action. The aim of this study was to investigate the effect of magnesium supplementation on IR in humans via systematic review of the available clinical trials. This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. A survey was conducted to select clinical trials related to the effects of this mineral in insulin sensitivity using the following databases: PubMed, SciVerse Scopus, ScienceDirect, and SciVerse Cochrane. After the selection process, 12 articles were identified as eligible, representing different clinical conditions and being free of restriction with regard to sex, age, ethnicity, and differential dosing/shape of magnesium. The results of eight clinical trials showed that supplementation with magnesium influences serum fasting glucose concentrations, and five trials determined an effect on fasting insulin levels. The results of seven studies demonstrated that mineral supplementation reduced homeostasis model assessment for IR values. The data of this systematic review provide evidence as to the benefits of magnesium supplementation in reducing IR in patients with hypomagnesemia presenting IR. However, new intervention studies are needed to elucidate the role of the nutrient in protection against this metabolic disorder, as well as the standardization of the type, dose, and time of magnesium supplementation. Copyright © 2017 Elsevier Inc. All rights reserved.

Alternate Phosphorylation/O-GlcNAc Modification on Human Insulin IRSs: A Road towards Impaired Insulin Signaling in Alzheimer and Diabetes

Directory of Open Access Journals (Sweden)

Zainab Jahangir

2014-01-01

Full Text Available Impaired insulin signaling has been thought of as important step in both Alzheimer’s disease (AD and type 2 diabetes mellitus (T2DM. Posttranslational modifications (PTMs regulate functions and interaction of insulin with insulin receptors substrates (IRSs and activate insulin signaling downstream pathways via autophosphorylation on several tyrosine (TYR residues on IRSs. Two important insulin receptor substrates 1 and 2 are widely expressed in human, and alternative phosphorylation on their serine (Ser and threonine (Thr residues has been known to block the Tyr phosphorylation of IRSs, thus inhibiting insulin signaling and promoting insulin resistance. Like phosphorylation, O-glycosylation modification is important PTM and inhibits phosphorylation on same or neighboring Ser/Thr residues, often called Yin Yang sites. Both IRS-1 and IRS-2 have been shown to be O-glycosylated; however exact sites are not determined yet. In this study, by using neuronal network based prediction methods, we found more than 50 Ser/Thr residues that have potential to be O-glycosylated and may act as possible sites as well. Moreover, alternative phosphorylation and O-glycosylation on IRS-1 Ser-312, 984, 1037, and 1101 may act as possible therapeutic targets to minimize the risk of AD and T2DM.

Differentiation of PDX1 gene-modified human umbilical cord mesenchymal stem cells into insulin-producing cells in vitro.

Science.gov (United States)

He, Dongmei; Wang, Juan; Gao, Yangjun; Zhang, Yuan

2011-12-01

Mesenchymal stem cells (MSCs) have significant advantages over other stem cell types, and greater potential for immediate clinical application. MSCs would be an interesting cellular source for treatment of type 1 diabetes. In this study, MSCs from human umbilical cord were differentiated into functional insulin-producing cells in vitro by introduction of the pancreatic and duodenal homeobox factor 1 (PDX1) and in the presence of induction factors. The expressions of cell surface antigens were detected by flow cytometry. After induction in an adipogenic medium or an osteogenic medium, the cells were observed by Oil Red O staining and alkaline phosphatase staining. Recombinant adenovirus carrying the PDX1 gene was constructed and MSCs were infected by the recombinant adenovirus, then treated with several inducing factors for differentiation into islet β-like cells. The expression of the genes and protein related to islet β-cells was detected by immunocytochemistry, RT-PCR and Western blot analysis. Insulin and C-peptide secretion were assayed. Our results show that the morphology and immunophenotype of MSCs from human umbilical cord were similar to those present in human bone marrow. The MSCs could be induced to differentiate into osteocytes and adipocytes. After induction by recombined adenovirus vector with induction factors, MSCs were aggregated and presented islet-like bodies. Dithizone staining of these cells was positive. The genes' expression related to islet β-cells was found. After induction, insulin and C-peptide secretion in the supernatant were significantly increased. In conclusion, our results demonstrated that PDX1 gene-modified human umbilical cord mesenchymal stem cells could be differentiated into insulin-producing cells in vitro.

Effect of training on insulin sensitivity of glucose uptake and lipolysis in human adipose tissue

DEFF Research Database (Denmark)

Stallknecht, B; Larsen, J J; Mikines, K J

2000-01-01

Training increases insulin sensitivity of both whole body and muscle in humans. To investigate whether training also increases insulin sensitivity of adipose tissue, we performed a three-step hyperinsulinemic, euglycemic clamp in eight endurance-trained (T) and eight sedentary (S) young men...... (glucose only). Adipose tissue blood flow was measured by (133)Xe washout. In the basal state, adipose tissue blood flow tended to be higher in T compared with S subjects, and in both groups blood flow was constant during the clamp. The change from basal in arterial-interstitial glucose concentration......-time: T, 44 +/- 9 min (n = 7); S, 102 +/- 23 min (n = 5); P training enhances insulin sensitivity of glucose uptake in subcutaneous adipose tissue and in skeletal muscle. Furthermore, interstitial glycerol data suggest that training also increases insulin sensitivity of lipolysis...

A New Method for Generating Insulin-Secreting Cells from Human Pancreatic Epithelial Cells After Islet Isolation Transformed by NeuroD1

Science.gov (United States)

Shimoda, Masayuki; Chen, Shuyuan; Noguchi, Hirofumi; Takita, Morihito; Sugimoto, Koji; Itoh, Takeshi; Chujo, Daisuke; Iwahashi, Shuichi; Naziruddin, Bashoo; Levy, Marlon F.

2014-01-01

Abstract The generation of insulin-secreting cells from nonendocrine pancreatic epithelial cells (NEPEC) has been demonstrated for potential clinical use in the treatment of diabetes. However, previous methods either had limited efficacy or required viral vectors, which hinder clinical application. In this study, we aimed to establish an efficient method of insulin-secreting cell generation from NEPEC without viral vectors. We used nonislet fractions from both research-grade human pancreata from brain-dead donors and clinical pancreata after total pancreatectomy with autologous islet transplantation to treat chronic pancreatitis. It is of note that a few islets could be mingled in the nonislet fractions, but their influence could be limited. The NeuroD1 gene was induced into NEPEC using an effective triple lipofection method without viral vectors to generate insulin-secreting cells. The differentiation was promoted by adding a growth factor cocktail into the culture medium. Using the research-grade human pancreata, the effective method showed high efficacy in the differentiation of NEPEC into insulin-positive cells that secreted insulin in response to a glucose challenge and improved diabetes after being transplanted into diabetic athymic mice. Using the clinical pancreata, similar efficacy was obtained, even though those pancreata suffered chronic pancreatitis. In conclusion, our effective differentiation protocol with triple lipofection method enabled us to achieve very efficient insulin-secreting cell generation from human NEPEC without viral vectors. This method offers the potential for supplemental insulin-secreting cell transplantation for both allogeneic and autologous islet transplantation. PMID:24845703

Pancreatic Transdifferentiation and Glucose-Regulated Production of Human Insulin in the H4IIE Rat Liver Cell Line

Directory of Open Access Journals (Sweden)

Binhai Ren

2016-04-01

Full Text Available Due to the limitations of current treatment regimes, gene therapy is a promising strategy being explored to correct blood glucose concentrations in diabetic patients. In the current study, we used a retroviral vector to deliver either the human insulin gene alone, the rat NeuroD1 gene alone, or the human insulin gene and rat NeuroD1 genes together, to the rat liver cell line, H4IIE, to determine if storage of insulin and pancreatic transdifferentiation occurred. Stable clones were selected and expanded into cell lines: H4IIEins (insulin gene alone, H4IIE/ND (NeuroD1 gene alone, and H4IIEins/ND (insulin and NeuroD1 genes. The H4IIEins cells did not store insulin; however, H4IIE/ND and H4IIEins/ND cells stored 65.5 ± 5.6 and 1475.4 ± 171.8 pmol/insulin/5 × 106 cells, respectively. Additionally, several β cell transcription factors and pancreatic hormones were expressed in both H4IIE/ND and H4IIEins/ND cells. Electron microscopy revealed insulin storage vesicles in the H4IIE/ND and H4IIEins/ND cell lines. Regulated secretion of insulin to glucose (0–20 mmol/L was seen in the H4IIEins/ND cell line. The H4IIEins/ND cells were transplanted into diabetic immunoincompetent mice, resulting in normalization of blood glucose. This data shows that the expression of NeuroD1 and insulin in liver cells may be a useful strategy for inducing islet neogenesis and reversing diabetes.

Skeletal muscle phosphatidylcholine and phosphatidylethanolamine are related to insulin sensitivity and respond to acute exercise in humans.

Science.gov (United States)

Newsom, Sean A; Brozinick, Joseph T; Kiseljak-Vassiliades, Katja; Strauss, Allison N; Bacon, Samantha D; Kerege, Anna A; Bui, Hai Hoang; Sanders, Phil; Siddall, Parker; Wei, Tao; Thomas, Melissa; Kuo, Ming Shang; Nemkov, Travis; D'Alessandro, Angelo; Hansen, Kirk C; Perreault, Leigh; Bergman, Bryan C

2016-06-01

Several recent reports indicate that the balance of skeletal muscle phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is a key determinant of muscle contractile function and metabolism. The purpose of this study was to determine relationships between skeletal muscle PC, PE and insulin sensitivity, and whether PC and PE are dynamically regulated in response to acute exercise in humans. Insulin sensitivity was measured via intravenous glucose tolerance in sedentary obese adults (OB; n = 14), individuals with type 2 diabetes (T2D; n = 15), and endurance-trained athletes (ATH; n = 15). Vastus lateralis muscle biopsies were obtained at rest, immediately after 90 min of cycle ergometry at 50% maximal oxygen consumption (V̇o2 max), and 2-h postexercise (recovery). Skeletal muscle PC and PE were measured via infusion-based mass spectrometry/mass spectrometry analysis. ATH had greater levels of muscle PC and PE compared with OB and T2D (P insulin sensitivity (both P insulin sensitivity among the entire cohort (r = -0.43, P = 0.01). Muscle PC and PE were altered by exercise, particularly after 2 h of recovery, in a highly group-specific manner. However, muscle PC:PE ratio remained unchanged in all groups. In summary, total muscle PC and PE are positively related to insulin sensitivity while PC:PE ratio is inversely related to insulin sensitivity in humans. A single session of exercise significantly alters skeletal muscle PC and PE levels, but not PC:PE ratio. Copyright © 2016 the American Physiological Society.

Evidence that phosphatidylcholine-specific phospholipase C is a key molecule mediating insulin-induced enhancement of gene expression from human cytomegalovirus promoter in CHO cells

OpenAIRE

Zhang, Yingpei; Katakura, Yoshinori; Seto, Perry; Shirahata, Sanetaka

1997-01-01

The signal transduction from insulin to its receptors and Ras has been extensively studied, while little has been reported beyond these steps. We found that the expression of human interleukin 6 gene under the control of immediate early gene promoter of human cytomegalovirus was enhanced by insulin sitmulation in Chinese hamster ovary cells. The induction effect of insulin was not significantly affected by inhibitors or activators of conventional protein kinase C, cAMP dependent protein kinas...

Treatment of dwarfism with recombinant human insulin-like growth factor-1.

Science.gov (United States)

Ranke, Michael B; Wölfle, Joachim; Schnabel, Dirk; Bettendorf, Markus

2009-10-01

The growth hormone-IGF (insulin-like growth factor) system plays a central role in hormonal growth regulation. Recombinant human (rh) growth hormone (GH) has been available since the late 1980s for replacement therapy in GH-deficient patients and for the stimulation of growth in patients with short stature of various causes. Growth promotion by GH occurs in part indirectly through the induction of IGF-1 synthesis. In primary disturbances of IGF-1 production, short stature can only be treated with recombinant human IGF-1 (rhIGF-1). rhIGF-1 was recently approved for this indication but can also be used to treat other conditions. Selective review of the literature on IGF-1 therapy, based on a PubMed search. In children with severe primary IGF-1 deficiency (a rare condition whose prevalence is less than 1:10,000), the prognosis for final height is very poor (ca. 130 cm), and IGF-1 therapy is the appropriate form of pathophysiologically based treatment. There is no alternative treatment at present. The subcutaneous administration of IGF-1 twice daily in doses of 80 to 120 microg/kg accelerates growth and increases final height by 12 to 15 cm, according to current data. There is, however, a risk of hypoglycemia, as IGF-1 has an insulin-like effect. As treatment with IGF-1 is complex, this new medication should only be prescribed, for the time being, by experienced pediatric endocrinologists and diabetologists.

Analyses of insulin-potentiating fragments of human growth hormone by computative simulation; essential unit for insulin-involved biological responses.

Science.gov (United States)

Ohkura, K; Hori, H

2000-07-01

We analyzed the structural features of insulin-potentiating fragments of human growth hormone by computative simulations. The peptides were designated from the N-terminus sequences of the hormone positions at 1-15 (hGH(1-15); H2N-Phe1-Pro2-Thr3-Ile4-Pro5-Leu6-Ser7-Arg8-L eu9-Phe10-Asp11-Asn12-Ala13-Met14-Leu15 -COOH), 6-13 (hGH(6-13)), 7-13 (hGH(7-13)) and 8-13 (hGH(8-13)), which enhanced insulin-producing hypoglycemia. In these peptide molecules, ionic bonds were predicted to form between 8th-arginyl residue and 11th-aspartic residue, and this intramolecular interaction caused the formation of a macrocyclic structure containing a tetrapeptide Arg8-Leu9-Phe10-Asp11. The peptide positions at 6-10 (hGH(6-10)), 9-13 (hGH(9-13)) and 10-13 (hGH(10-13)) did not lead to a macrocyclic formation in the molecules, and had no effect on the insulin action. Although beta-Ala13hGH(1-15), in which the 13th-alanine was replaced by a beta-alanyl residue, had no effect on insulin-producing hypoglycemia, the macrocyclic region (Arg8-Leu9-Phe10-Asp11) was observed by the computative simulation. An isothermal vibration analysis of both of beta-Ala13hGH(1-15) and hGH(1-15) peptide suggested that beta-Ala13hGH(1-15) is molecule was more flexible than hGH(1-15); C-terminal carboxyl group of Leu15 easily accessed to Arg8 and inhibited the ionic bond formation between Arg8 and Asp11 in beta-Ala13hGH(1-15). The peptide of hGH(8-13) dose-dependently enhanced the insulin-involved fatty acid synthesis in rat white adipocytes, and stabilized the C6-NBD-PC (1-acyl-2-[6-[(7-nitro-2,1,3benzoxadiazol-4-yl)amino]-caproyl]-sn- glycero-3-phosphatidylcholine) model membranes. In contrast, hGH(9-13) had no effect both on the fatty acid synthesis and the membrane stability. In the same culture conditions as the fatty acid synthesis assay, hGH(8-13) had no effect on the transcript levels of glucose transporter isoforms (GLUT 1, 4) and hexokinase isozymes (HK I, II) in rat white adipocytes. Judging from

Human adipose tissue-derived mesenchymal stem cells differentiate into insulin, somatostatin, and glucagon expressing cells

International Nuclear Information System (INIS)

Timper, Katharina; Seboek, Dalma; Eberhardt, Michael; Linscheid, Philippe; Christ-Crain, Mirjam; Keller, Ulrich; Mueller, Beat; Zulewski, Henryk

2006-01-01

Mesenchymal stem cells (MSC) from mouse bone marrow were shown to adopt a pancreatic endocrine phenotype in vitro and to reverse diabetes in an animal model. MSC from human bone marrow and adipose tissue represent very similar cell populations with comparable phenotypes. Adipose tissue is abundant and easily accessible and could thus also harbor cells with the potential to differentiate in insulin producing cells. We isolated human adipose tissue-derived MSC from four healthy donors. During the proliferation period, the cells expressed the stem cell markers nestin, ABCG2, SCF, Thy-1 as well as the pancreatic endocrine transcription factor Isl-1. The cells were induced to differentiate into a pancreatic endocrine phenotype by defined culture conditions within 3 days. Using quantitative PCR a down-regulation of ABCG2 and up-regulation of pancreatic developmental transcription factors Isl-1, Ipf-1, and Ngn3 were observed together with induction of the islet hormones insulin, glucagon, and somatostatin

Immature transformed rat islet beta-cells differentially express C-peptides derived from the genes coding for insulin I and II as well as a transfected human insulin gene

DEFF Research Database (Denmark)

Blume, N; Petersen, J S; Andersen, L C

1992-01-01

is induced in the transformed heterogeneous rat islet cell clone, NHI-6F, by transient in vivo passage. During this process a transfected human insulin gene is coactivated with the endogenous nonallelic rat insulin I and II genes. Newly established cultures from NHI-6F insulinomas having a high frequency...

Reduced insulin exocytosis in human pancreatic β-cells with gene variants linked to type 2 diabetes

DEFF Research Database (Denmark)

Rosengren, Anders H; Braun, Matthias; Mahdi, Taman

2012-01-01

The majority of genetic risk variants for type 2 diabetes (T2D) affect insulin secretion, but the mechanisms through which they influence pancreatic islet function remain largely unknown. We functionally characterized human islets to determine secretory, biophysical, and ultrastructural features ...

Branched chain amino acid suppressed insulin-initiated proliferation of human cancer cells through induction of autophagy.

Science.gov (United States)

Wubetu, Gizachew Yismaw; Utsunomiya, Tohru; Ishikawa, Daichi; Ikemoto, Tetsuya; Yamada, Shinichiro; Morine, Yuji; Iwahashi, Shuichi; Saito, Yu; Arakawa, Yusuke; Imura, Satoru; Arimochi, Hideki; Shimada, Mitsuo

2014-09-01

Branched chain amino acid (BCAA) dietary supplementation inhibits activation of the insulin-like growth factor (IGF)/IGF-I receptor (IGF-IR) axis in diabetic animal models. However, the in vitro effect of BCAA on human cancer cell lines under hyper-insulinemic conditions remains unclear. Colon (HCT-116) and hepatic (HepG2) tumor cells were treated with varying concentrations of BCAA with or without fluorouracil (5-FU). The effect of BCAA on insulin-initiated proliferation was determined. Gene and protein expression was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. BCAA supplementation had no significant effect on cell proliferation and did not show significant synergistic or antagonistic effects with 5-FU. However, BCAA significantly decreased insulin-initiated proliferation of human colon and hepatic cancer cell lines in vitro. BCAA supplementation caused a marked decrease in activated IGF-IR expression and significantly enhanced both mRNA and protein expression of LC3-II and BECN1 (BECLIN-1). BCAA could be a useful chemopreventive modality for cancer in hyperinsulinemic conditions. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Intraportal injection of insulin-producing cells generated from human bone marrow mesenchymal stem cells decreases blood glucose level in diabetic rats.

Science.gov (United States)

Tsai, Pei-Jiun; Wang, Hwai-Shi; Lin, Chi-Hung; Weng, Zen-Chung; Chen, Tien-Hua; Shyu, Jia-Fwu

2014-01-01

We studied the process of trans-differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) into insulin-producing cells. Streptozotocin (STZ)-induced diabetic rat model was used to study the effect of portal vein transplantation of these insulin-producing cells on blood sugar levels. The BM-MSCs were differentiated into insulin-producing cells under defined conditions. Real-time PCR, immunocytochemistry and glucose challenge were used to evaluate in vitro differentiation. Flow cytometry showed that hBM-MSCs were strongly positive for CD44, CD105 and CD73 and negative for hematopoietic markers CD34, CD38 and CD45. Differentiated cells expressed C-peptide as well as β-cells specific genes and hormones. Glucose stimulation increased C-peptide secretion in these cells. The insulin-producing, differentiated cells were transplanted into the portal vein of STZ-induced diabetic rats using a Port-A catheter. The insulin-producing cells were localized in the liver of the recipient rat and expressed human C-peptide. Blood glucose levels were reduced in diabetic rats transplanted with insulin-producing cells. We concluded that hBM-MSCs could be trans-differentiated into insulin-producing cells in vitro. Portal vein transplantation of insulin-producing cells alleviated hyperglycemia in diabetic rats.

Insulin-increased L-arginine transport requires A(2A adenosine receptors activation in human umbilical vein endothelium.

Directory of Open Access Journals (Sweden)

Enrique Guzmán-Gutiérrez

Full Text Available Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1. This process involves the activation of A(2A adenosine receptors (A(2AAR in human umbilical vein endothelial cells (HUVECs. Insulin increases hCAT-1 activity and expression in HUVECs, and A(2AAR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A(2AAR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37°C in the absence or presence of nitrobenzylthioinosine (NBTI, 10 µmol/L, adenosine transport inhibitor and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR, and SLC7A1 (for hCAT-1 reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent K(m for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1(-1606 or pGL3-hCAT-1(-650 constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1(-1606, and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A(2AAR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.

Characterization of the growth of murine fibroblasts that express human insulin receptors. II. Interaction of insulin with other growth factors

International Nuclear Information System (INIS)

Randazzo, P.A.; Jarett, L.

1990-01-01

The effects of insulin-like growth factor-1 (IGF-1), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and insulin on DNA synthesis were studied in murine fibroblasts transfected with an expression vector containing human insulin receptor cDNA (NIH 3T3/HIR) and the parental NIH 3T3 cells. In NIH 3T3/HIR cells, individual growth factors in serum-free medium stimulated DNA synthesis with the following relative efficacies: insulin greater than or equal to 10% fetal calf serum greater than PDGF greater than IGF-1 much greater than EGF. In comparison, the relative efficacies of these factors in stimulating DNA synthesis by NIH 3T3 cells were 10% fetal calf serum greater than PDGF greater than EGF much greater than IGF-1 = insulin. In NIH 3T3/HIR cells, EGF was synergistic with 1-10 ng/ml insulin but not with 100 ng/ml insulin or more. Synergy of PDGF or IGF-1 with insulin was not detected. In the parental NIH 3T3 cells, insulin and IGF-1 were found to be synergistic with EGF (1 ng/ml), PDGF (100 ng/ml), and PDGF plus EGF. In NIH 3T3/HIR cells, the lack of interaction of insulin with other growth factors was also observed when the percentage of cells synthesizing DNA was examined. Despite insulin's inducing only 60% of NIH 3T3/HIR cells to incorporate thymidine, addition of PDGF, EGF, or PDGF plus EGF had no further effect. In contrast, combinations of growth factors resulted in 95% of the parental NIH 3T3 cells synthesizing DNA. The independence of insulin-stimulated DNA synthesis from other mitogens in the NIH 3T3/HIR cells is atypical for progression factor-stimulated DNA synthesis and is thought to be partly the result of insulin receptor expression in an inappropriate context or quantity

Human insulin polymorphism upon ligand binding and pH variation: the case of 4-ethylresorcinol.

Science.gov (United States)

Fili, S; Valmas, A; Norrman, M; Schluckebier, G; Beckers, D; Degen, T; Wright, J; Fitch, A; Gozzo, F; Giannopoulou, A E; Karavassili, F; Margiolaki, I

2015-09-01

This study focuses on the effects of the organic ligand 4-ethylresorcinol on the crystal structure of human insulin using powder X-ray crystallography. For this purpose, systematic crystallization experiments have been conducted in the presence of the organic ligand and zinc ions within the pH range 4.50-8.20, while observing crystallization behaviour around the isoelectric point of insulin. High-throughput crystal screening was performed using a laboratory X-ray diffraction system. The most representative samples were selected for synchrotron X-ray diffraction measurements, which took place at the European Synchrotron Radiation Facility (ESRF) and the Swiss Light Source (SLS). Four different crystalline polymorphs have been identified. Among these, two new phases with monoclinic symmetry have been found, which are targets for the future development of microcrystalline insulin drugs.

Increased bioactive lipids content in human subcutaneous and epicardial fat tissue correlates with insulin resistance.

Science.gov (United States)

Błachnio-Zabielska, Agnieszka U; Baranowski, Marcin; Hirnle, Tomasz; Zabielski, Piotr; Lewczuk, Anna; Dmitruk, Iwona; Górski, Jan

2012-12-01

Obesity is a risk factor for metabolic diseases. Intramuscular lipid accumulation of ceramides, diacylglycerols, and long chain acyl-CoA is responsible for the induction of insulin resistance. These lipids are probably implicated in obesity-associated insulin resistance not only in skeletal muscle but also in fat tissue. Only few data are available about ceramide content in human subcutaneous adipose tissue. However, there are no data on DAG and LCACoA content in adipose tissue. The aim of our study was to measure the lipids content in human SAT and epicardial adipose tissue we sought to determine the bioactive lipids content by LC/MS/MS in fat tissue from lean non-diabetic, obese non-diabetic, and obese diabetic subjects and test whether the lipids correlate with HOMA-IR. We found, that total content of measured lipids was markedly higher in OND and OD subjects in both types of fat tissue (for all p lipids content is greater in subcutaneous and epicardial fat tissue and the particular lipids content positively correlates with HOMA-IR.

Direct in vivo characterization of delta 5 desaturase activity in humans by deuterium labeling: Effect of insulin

International Nuclear Information System (INIS)

el Boustani, S.; Causse, J.E.; Descomps, B.; Monnier, L.; Mendy, F.; Crastes de Paulet, A.

1989-01-01

The conversion of dihomogamma linolenic acid (DHLA) into arachidonic acid (AA) was compared in normal subjects and diabetic patients before and after treatment with insulin. The kinetics of the incorporation of deuterium-labeled DHLA and its conversion product, deuterium-labeled AA, was determined in plasma triglycerides, plasma phospholipids, and platelet lipids of subjects after ingestion of 2 g of the labeled precursor. Analysis was performed by gas liquid chromatography-mass spectrometry using multiple ion detection. In normal subjects, the deuterium-labeled DHLA concentration rose to 24 to 69 mg/L in plasma triglycerides four to nine hours after ingestion and to 20 to 34 mg/L in plasma phospholipids about four hours later. Deuterium-labeled AA appeared at 12 hours, rose to 2.4 to 3.8 mg/L between 48 and 72 hours in plasma phospholipids, but remained at the limit of detection in plasma triglycerides and was undetectable in platelet lipids. In diabetic patients both before and after insulin treatment, the deuterium-labeled DHLA concentration in plasma triglycerides and in plasma phospholipids followed the same pattern as in normal subjects. However, the deuterium-labeled arachidonic acid concentration was below 1 mg/L in plasma phospholipids before insulin. After insulin treatment the patients recovered normal DHLA metabolism because deuterium-labeled AA rose in phospholipids to a mean value of 3.5 mg/L, which is in the same range as that observed in normal subjects (3.2 mg/L). The present data provide direct evidence for the conversion of DHLA into AA in humans. The effect of insulin and the data from the literature of animal studies suggest insulin dependence of delta 5 desaturase in humans

Inconsistent formation and nonfunction of insulin-positive cells from pancreatic endoderm derived from human embryonic stem cells in athymic nude rats.

Science.gov (United States)

Matveyenko, Aleksey V; Georgia, Senta; Bhushan, Anil; Butler, Peter C

2010-11-01

Embryonic stem cell therapy has been proposed as a therapeutic strategy to restore β-cell mass and function in T1DM. Recently, a group from Novocell (now ViaCyte) reported successful development of glucose-responsive islet-like structures after implantation of pancreatic endoderm (PE) derived from human embryonic stem cells (hESC) into immune-deficient mice. Our objective was to determine whether implantation of hESC-derived pancreatic endoderm from Novocell into athymic nude rats results in development of viable glucose-responsive pancreatic endocrine tissue. Athymic nude rats were implanted with PE derived from hESC either via implantation into the epididymal fat pads or by subcutaneous implantation into TheraCyte encapsulation devices for 20 wk. Blood glucose, weight, and human insulin/C-peptide secretion were monitored by weekly blood draws. Graft β-cell function was assessed by a glucose tolerance test, and graft morphology was assessed by immunohistochemistry and immunofluorescence. At 20 wk postimplantation, epididymal fat-implanted PE progressed to develop islet-like structures in 50% of implants, with a mean β-cell fractional area of 0.8 ± 0.3%. Human C-peptide and insulin were detectable, but at very low levels (C-peptide = 50 ± 26 pmol/l and insulin = 15 ± 7 pmol/l); however, there was no increase in human C-peptide/insulin levels after glucose challenge. There was no development of viable pancreatic tissue or meaningful secretory function when human PE was implanted in the TheraCyte encapsulation devices. These data confirm that islet-like structures develop from hESC differentiated to PE by the protocol developed by NovoCell. However, the extent of endocrine cell formation and secretory function is not yet sufficient to be clinically relevant.

Two insulin-like growth factor I messenger RNAs are expressed in human liver

International Nuclear Information System (INIS)

Rotwein, P.

1986-01-01

Through use of a synthetic radiolabelled oligonucleotide probe, human insulin-like growth factor I (IGF-I) cDNA clones were isolated from a liver library. Two types of cDNAs were defined by restriction enzyme analysis and DNA sequencing. Both encode IGF-I precursors of either 195 or 153 amino acids. The two predicted protein precursors are identical from their amino terminus to a lysine residue 16 codons beyond the IGF-I sequence, and then they diverge. Both cDNAs predict additional unique carboxyl-terminal extension peptides. Since there is only one IGF-I gene in the human genome, the finding of two different cDNAs suggests that alternative RNA processing plays a role in IGF-I gene expression. The functions of the different extension peptides remain to be elucidates

Insulin acutely improves mitochondrial function of rat and human skeletal muscle by increasing coupling efficiency of oxidative phosphorylation.

Science.gov (United States)

Nisr, Raid B; Affourtit, Charles

2014-02-01

Insulin is essential for the regulation of fuel metabolism and triggers the uptake of glucose by skeletal muscle. The imported glucose is either stored or broken down, as insulin stimulates glycogenesis and ATP synthesis. The mechanism by which ATP production is increased is incompletely understood at present and, generally, relatively little functional information is available on the effect of insulin on mitochondrial function. In this paper we have exploited extracellular flux technology to investigate insulin effects on the bioenergetics of rat (L6) and human skeletal muscle myoblasts and myotubes. We demonstrate that a 20-min insulin exposure significantly increases (i) the cell respiratory control ratio, (ii) the coupling efficiency of oxidative phosphorylation, and (iii) the glucose sensitivity of anaerobic glycolysis. The improvement of mitochondrial function is explained by an insulin-induced immediate decrease of mitochondrial proton leak. Palmitate exposure annuls the beneficial mitochondrial effects of insulin. Our data improve the mechanistic understanding of insulin-stimulated ATP synthesis, and reveal a hitherto undisclosed insulin sensitivity of cellular bioenergetics that suggests a novel way of detecting insulin responsiveness of cells. © 2013.

Insulin acutely improves mitochondrial function of rat and human skeletal muscle by increasing coupling efficiency of oxidative phosphorylation☆

Science.gov (United States)

Nisr, Raid B.; Affourtit, Charles

2014-01-01

Insulin is essential for the regulation of fuel metabolism and triggers the uptake of glucose by skeletal muscle. The imported glucose is either stored or broken down, as insulin stimulates glycogenesis and ATP synthesis. The mechanism by which ATP production is increased is incompletely understood at present and, generally, relatively little functional information is available on the effect of insulin on mitochondrial function. In this paper we have exploited extracellular flux technology to investigate insulin effects on the bioenergetics of rat (L6) and human skeletal muscle myoblasts and myotubes. We demonstrate that a 20-min insulin exposure significantly increases (i) the cell respiratory control ratio, (ii) the coupling efficiency of oxidative phosphorylation, and (iii) the glucose sensitivity of anaerobic glycolysis. The improvement of mitochondrial function is explained by an insulin-induced immediate decrease of mitochondrial proton leak. Palmitate exposure annuls the beneficial mitochondrial effects of insulin. Our data improve the mechanistic understanding of insulin-stimulated ATP synthesis, and reveal a hitherto undisclosed insulin sensitivity of cellular bioenergetics that suggests a novel way of detecting insulin responsiveness of cells. PMID:24212054

Effect of starvation on human muscle protein metabolism and its response to insulin

International Nuclear Information System (INIS)

Fryburg, D.A.; Barrett, E.J.; Louard, R.J.; Gelfand, R.A.

1990-01-01

To assess the effect of fasting on muscle protein turnover in the basal state and in response to insulin, we measured forearm amino acid kinetics, using [3H]phenylalanine (Phe) and [14C]leucine (Leu) infused systemically, in eight healthy subjects after 12 (postabsorptive) and 60 h of fasting. After a 150-min basal period, forearm local insulin concentration was selectively raised by approximately 25 muU/ml for 150 min by intra-arterial insulin infusion (0.02 mU.kg-1. min-1). The 60-h fast increased urine nitrogen loss and whole body Leu flux and oxidation (by 50-75%, all P less than 0.02). Post-absorptively, forearm muscle exhibited a net release of Phe and Leu, which increased two- to threefold after the 60-h fast (P less than 0.05); this effect was mediated exclusively by accelerated local rates of amino acid appearance (Ra), with no reduction in rates of disposal (Rd). Local hyperinsulinemia in the postabsorptive condition caused a twofold increase in forearm glucose uptake (P less than 0.01) and completely suppressed the net forearm output of Phe and Leu (P less than 0.02). After the 60-h fast, forearm glucose disposal was depressed basally and showed no response to insulin; in contrast, insulin totally abolished the accelerated net forearm release of Phe and Leu. The action of insulin to reverse the augmented net release of Phe and Leu was mediated exclusively by approximately 40% suppression of Ra (P less than 0.02) rather than a stimulation of Rd. We conclude that in short-term fasted humans (1) muscle amino acid output accelerates due to increased proteolysis rather than reduced protein synthesis, and (2) despite its catabolic state and a marked impairment in insulin-mediated glucose disposal, muscle remains sensitive to insulin's antiproteolytic action

Effect of starvation on human muscle protein metabolism and its response to insulin

Energy Technology Data Exchange (ETDEWEB)

Fryburg, D.A.; Barrett, E.J.; Louard, R.J.; Gelfand, R.A. (Yale Univ. School of Medicine, New Haven, CT (USA))

1990-10-01

To assess the effect of fasting on muscle protein turnover in the basal state and in response to insulin, we measured forearm amino acid kinetics, using (3H)phenylalanine (Phe) and (14C)leucine (Leu) infused systemically, in eight healthy subjects after 12 (postabsorptive) and 60 h of fasting. After a 150-min basal period, forearm local insulin concentration was selectively raised by approximately 25 muU/ml for 150 min by intra-arterial insulin infusion (0.02 mU.kg-1. min-1). The 60-h fast increased urine nitrogen loss and whole body Leu flux and oxidation (by 50-75%, all P less than 0.02). Post-absorptively, forearm muscle exhibited a net release of Phe and Leu, which increased two- to threefold after the 60-h fast (P less than 0.05); this effect was mediated exclusively by accelerated local rates of amino acid appearance (Ra), with no reduction in rates of disposal (Rd). Local hyperinsulinemia in the postabsorptive condition caused a twofold increase in forearm glucose uptake (P less than 0.01) and completely suppressed the net forearm output of Phe and Leu (P less than 0.02). After the 60-h fast, forearm glucose disposal was depressed basally and showed no response to insulin; in contrast, insulin totally abolished the accelerated net forearm release of Phe and Leu. The action of insulin to reverse the augmented net release of Phe and Leu was mediated exclusively by approximately 40% suppression of Ra (P less than 0.02) rather than a stimulation of Rd. We conclude that in short-term fasted humans (1) muscle amino acid output accelerates due to increased proteolysis rather than reduced protein synthesis, and (2) despite its catabolic state and a marked impairment in insulin-mediated glucose disposal, muscle remains sensitive to insulin's antiproteolytic action.

[Solid state isotope hydrogen exchange for deuterium and tritium in human gene-engineered insulin].

Science.gov (United States)

Zolotarev, Yu A; Dadayan, A K; Kozik, V S; Gasanov, E V; Nazimov, I V; Ziganshin, R Kh; Vaskovsky, B V; Murashov, A N; Ksenofontov, A L; Haribin, O N; Nikolaev, E N; Myasoedov, N F

2014-01-01

The reaction of high temperature solid state catalytic isotope exchange in peptides and proteins under the action of catalyst-activated spillover hydrogen was studied. The reaction of human gene-engineered insulin with deuterium and tritium was conducted at 120-140° C to produce insulin samples containing 2-6 hydrogen isotope atoms. To determine the distribution of the isotope label over tritium-labeled insulin's amino acid residues, oxidation of the S-S bonds of insulin by performic acid was performed and polypeptide chains isolated; then their acid hydrolysis, amino acid analysis and liquid scintillation counts of tritium in the amino acids were conducted. The isotope label was shown to be incorporated in all amino acids of the protein, with the peptide fragment FVNQHLCGSHLVE of the insulin β-chain showing the largest incorporation. About 45% of the total protein isotope label was incorporated in His5 and His10 of this fragment. For the analysis of isotope label distribution in labeled insulin's peptide fragments, the recovery of the S-S bonds by mercaptoethanol, the enzymatic hydrolysis by glutamyl endopeptidase from Bacillus intermedius and HPLC division of the resulting peptides were carried out. Attribution of the peptide fragments formed due to hydrolysis at the Glu-X bond in the β-chain was accomplished by mass spectrometry. Mass spectrometry analysis data of the deuterium-labeled insulin samples' isotopomeric composition showed that the studied solid state isotope exchange reaction equally involved all the protein molecules. Biological studying of tritium-labeled insulin showed its physiological activity to be completely retained.

In vitro generation of functional insulin-producing cells from lipoaspirated human adipose tissue-derived stem cells.

Science.gov (United States)

Mohamad Buang, Mohamad Lizan; Seng, Heng Kien; Chung, Lee Han; Saim, Aminuddin Bin; Idrus, Ruszymah Bt Hj

2012-01-01

Tissue engineering strategy has been considered as an alternative treatment for diabetes mellitus due to lack of permanent pharmaceutical treatment and islet donors for transplantation. Various cell lines have been used to generate functional insulin-producing cells (IPCs) including progenitor pancreatic cell lines, embryonic stem cells (ESCs), umbilical cord blood stem cells (UCB-SCs), adult bone marrow stem cells (BMSCs), and adipose tissue-derived stem cells (ADSCs). Human ADSCs from lipoaspirated abdominal fat tissue was differentiated into IPCs following a two-step induction protocol based on a combination of alternating high and low glucose, nicotinamide, activin A and glucagon-like peptide 1 (GLP-1) for a duration of 3 weeks. During differentiation, histomorphological changes of the stem cells towards pancreatic β-islet characteristics were observed via light microscope and transmission electron microscope (TEM). Dithizone (DTZ) staining, which is selective towards IPCs, was used to stain the new islet-like cells. Production of insulin hormone by the cells was analyzed via enzyme-linked immunosorbent assay (ELISA), whereas its hormonal regulation was tested via a glucose challenge test. Histomorphological changes of the differentiated cells were noted to resemble pancreatic β-cells, whereas DTZ staining positively stained the cells. The differentiated cells significantly produced human insulin as compared to the undifferentiated ADSCs, and its production was increased with an increase of glucose concentration in the culture medium. These initial data indicate that human lipoaspirated ADSCs have the potential to differentiate into functional IPCs, and could be used as a therapy to treat diabetes mellitus in the future. Copyright © 2012 IMSS. Published by Elsevier Inc. All rights reserved.

Expression of human choline kinase in NIH 3T3 fibroblasts increases the mitogenic potential of insulin and insulin-like growth factor I.

Science.gov (United States)

Chung, T; Huang, J S; Mukherjee, J J; Crilly, K S; Kiss, Z

2000-05-01

In mammalian cells, growth factors, oncogenes, and carcinogens stimulate phosphocholine (PCho) synthesis by choline kinase (CK), suggesting that PCho may regulate cell growth. To validate the role of PCho in mitogenesis, we determined the effects of insulin, insulin-like growth factor I (IGF-I), and other growth factors on DNA synthesis in NIH 3T3 fibroblast sublines highly expressing human choline kinase (CK) without increasing phosphatidylcholine synthesis. In serum-starved CK expressor cells, insulin and IGF-I stimulated DNA synthesis, p70 S6 kinase (p70 S6K) activity, phosphatidylinositol 3-kinase (PI3K) activity, and activating phosphorylation of p42/p44 mitogen-activated protein kinases (MAPK) to greater extents than in the corresponding vector control cells. Furthermore, the CK inhibitor hemicholinium-3 (HC-3) inhibited insulin- and IGF-I-induced DNA synthesis in the CK overexpressors, but not in the vector control cells. The results indicate that high cellular levels of PCho potentiate insulin- and IGF-I-induced DNA synthesis by MAPK- and p70 S6K-regulated mechanisms.

Circulating ApoJ is closely associated with insulin resistance in human subjects.

Science.gov (United States)

Seo, Ji A; Kang, Min-Cheol; Ciaraldi, Theodore P; Kim, Sang Soo; Park, Kyong Soo; Choe, Charles; Hwang, Won Min; Lim, Dong Mee; Farr, Olivia; Mantzoros, Christos; Henry, Robert R; Kim, Young-Bum

2018-01-01

Insulin resistance is a major risk factor for type 2 diabetes. ApolipoproteinJ (ApoJ) has been implicated in altered pathophysiologic states including cardiovascular and Alzheimer's disease. However, the function of ApoJ in regulation of glucose homeostasis remains unclear. This study sought to determine whether serum ApoJ levels are associated with insulin resistance in human subjects and if they change after interventions that improve insulin sensitivity. Serum ApoJ levels and insulin resistance status were assessed in nondiabetic (ND) and type 2 diabetic (T2D) subjects. The impacts of rosiglitazone or metformin therapy on serum ApoJ levels and glucose disposal rate (GDR) during a hyperinsulinemic/euglycemic clamp were evaluated in a separate cohort of T2D subjects. Total ApoJ protein or that associated with the HDL and LDL fractions was measured by immunoblotting or ELISA. Fasting serum ApoJ levels were greatly elevated in T2D subjects (ND vs T2D; 100±8.3 vs. 150.6±8.5AU, Pinsulin, HOMA-IR, and BMI. ApoJ levels were significantly and independently associated with HOMA-IR, even after adjustment for age, sex, and BMI. Rosiglitazone treatment in T2D subjects resulted in a reduction in serum ApoJ levels (before vs. after treatment; 100±13.9 vs. 77±15.2AU, P=0.015), whereas metformin had no effect on ApoJ levels. The change in ApoJ levels during treatment was inversely associated with the change in GDR. Interestingly, ApoJ content in the LDL fraction was inversely associated with HOMA-IR. Serum ApoJ levels are closely correlated with the magnitude of insulin resistance regardless of obesity, and decrease along with improvement of insulin resistance in response only to rosiglitazone in type 2 diabetes. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute systemic insulin intolerance does not alter the response of the Akt/GSK-3 pathway to environmental hypoxia in human skeletal muscle

DEFF Research Database (Denmark)

D'Hulst, Gommaar; Sylow, Lykke; Hespel, Peter

2015-01-01

PURPOSE: To investigate how acute environmental hypoxia regulates blood glucose and downstream intramuscular insulin signaling after a meal in healthy humans. METHODS: Fifteen subjects were exposed for 4 h to normoxia (NOR) or to normobaric hypoxia (HYP, FiO2 = 0.11) in a randomized order 40 min ...... insulin intolerance developed independently of defects in conventional insulin signaling in skeletal muscle....

Sulfate Anion Delays the Self-Assembly of Human Insulin by Modifying the Aggregation Pathway

OpenAIRE

Owczarz, Marta; Arosio, Paolo

2014-01-01

The understanding of the molecular mechanisms underlying protein self-assembly and of their dependence on solvent composition has implications in a large number of biological and biotechnological systems. In this work, we characterize the aggregation process of human insulin at acidic pH in the presence of sulfate ions using a combination of Thioflavin T fluorescence, dynamic light scattering, size exclusion chromatography, Fourier transform infrared spectroscopy, and transmission electron mi...

The road to the first, fully active and more stable human insulin variant with an additional disulfide bond

DEFF Research Database (Denmark)

Vinther, Tine N.; Kjeldsen, Thomas B.; Jensen, Knud Jørgen

2015-01-01

Insulin, a small peptide hormone, is crucial in maintaining blood glucose homeostasis. The stability and activity of the protein is directed by an intricate system involving disulfide bonds to stabilize the active monomeric species and by their non-covalent oligomerization. All known insulin...... variants in vertebrates consist of two peptide chains and have six cysteine residues, which form three disulfide bonds, two of them link the two chains and a third is an intra-chain bond in the A-chain. This classical insulin fold appears to have been conserved over half a billion years of evolution. We...... addressed the question whether a human insulin variant with four disulfide bonds could exist and be fully functional. In this review, we give an overview of the road to engineering four-disulfide bonded insulin analogs. During our journey, we discovered several active four disulfide bonded insulin analogs...

Characterization of the growth of murine fibroblasts that express human insulin receptors. I. The effect of insulin in the absence of other growth factors

International Nuclear Information System (INIS)

Randazzo, P.A.; Morey, V.A.; Polishook, A.K.; Jarett, L.

1990-01-01

The effect of insulin on the growth of murine fibroblasts transfected with an expression vector containing human insulin receptor cDNA (NIH 3T3/HIR) and the parental cells (NIH/3T3) was characterized. Insulin in the absence of other mitogens increased the rate of incorporation of thymidine into NIH 3T3/HIR cells with a half-maximal response occurring at an insulin concentration of 35 ng/ml and a maximal response that was equivalent to that elicited by 10% fetal calf serum. The thymidine incorporation rate was increased by 12 h, was maximal at approximately 16 h, and returned to basal rates at 24 h after the addition of insulin. Insulin induced a maximum of 65% of cells to incorporate thymidine. The increased DNA synthesis was accompanied by net growth. Addition of insulin to the NIH 3T3/HIR cells resulted in increased DNA content with a half-maximal response occurring at approximately 30 ng/ml insulin and a maximal response equivalent to that elicited by serum. An increase in cell number detected after the addition of insulin to the NIH 3T3/HIR suggests that the cells had progressed through mitosis. Insulin did not increase the rate of thymidine incorporation, DNA content, or number of the parental NIH 3T3 cells. These data show that insulin, in the absence of a second mitogen, is able to induce NIH 3T3/HIR fibroblasts to traverse the cell cycle

Thermodynamic and kinetic studies of As2O3 toxicological effects on human insulin in generation diabetes mellitus

Science.gov (United States)

Mohsennia, Mohsen; Motaharinejad, Atieh; Rafiee-Pour, Hossain-Ali; Torabbeigi, Marzieh

2017-12-01

The interaction of arsenic trioxide with human insulin was investigated by circular dichroism (CD), cyclic voltammetry and electrophoresis techniques. The interfacial behavior of insulin in presence of As2O3 onto the Ag electrode surface was studied at 310 K in phosphate buffer solution (PBS). According to Far-UV CD spectroscopy results, As2O3 caused to decrease in structural compactness and variety of alpha helix into beta structures. Near-UV CD indicated that As2O3 dissociates disulfide linkage in insulin structure. The kinetic parameters, including charge-transfer coefficient and apparent heterogeneous electron transfer rate constant were also determined. The thermodynamic parameters of insulin denaturation in presence of arsenic trioxide were calculated and reported. The obtained results indicated strong adsorption of insulin in presence of arsenic trioxide onto the Ag surface via chemisorptions.

High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression.

Directory of Open Access Journals (Sweden)

Rikard G Fred

Full Text Available BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB is required for stabilization of insulin mRNA and the PTB mRNA 3'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY/PRINCIPAL FINDINGS: Human islets were cultured for 24 hours in the presence of low (5.6 mM or high glucose (20 mM. Islets were also exposed to sodium palmitate or the proinflammatory cytokines IL-1beta and IFN-gamma, since saturated free fatty acids and cytokines also cause islet dysfunction. RNA was then isolated for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB was analyzed by immunoblotting following culture at low or high glucose. Culture in high glucose resulted in increased islet contents of miR-133a and reduced contents of miR-146. Cytokines increased the contents of miR-146. The insulin and PTB mRNA contents were unaffected by high glucose. However, both PTB protein levels and insulin biosynthesis rates were decreased in response to high glucose. The miR-133a inhibitor prevented the high glucose-induced decrease in PTB and insulin biosynthesis, and the miR-133a precursor decreased PTB levels and insulin biosynthesis similarly to high glucose. CONCLUSION: Prolonged high-glucose exposure down-regulates PTB levels and insulin biosynthesis rates in human islets by increasing miR-133a levels. We propose that this mechanism

Biological and Clinical Study of 6-Deoxy-6-Iodo-D-Glucose: a iodinated tracer of glucose transport and of insulin-resistance in human

International Nuclear Information System (INIS)

Barone-Rochette, Gilles

2013-01-01

Insulin resistance (IR), characterized by a depressed cellular sensitivity to insulin in insulin-sensitive organs, is a central feature to obesity, the metabolic syndrome, and diabetes mellitus and leads to increase cardiovascular diseases, particularly heart failure. All these events are today serious public health problems. But actually, there is no simple tool to measure insulin resistance. The gold standard technique remains the hyperinsulinemic euglycemic clamp. However, the complexity and length of this technique render it unsuitable for routine clinical use. Many methods or index have been proposed to assess insulin resistance in human, but none have shown enough relevance to be used in clinical use. The U1039 INSERM unit previously has validated a new tracer of glucose transport, radiolabelled with 123 iodine and has developed a fast and simple imaging protocol with a small animal gamma camera, which allows the obtaining of an IR index for each organ, showing more discriminating for the heart. The project of my thesis was the human transfer of this measurement technique, perfectly validated in animal. The first part of this thesis evaluated to tolerance, in vivo kinetics, distribution and dosimetry of novel tracer of glucose transport, the [ 123 I]-6DIG. The safeties of new tracer and measurement technique were adequate. There were no adverse effects with excellent tolerance of the whole protocol. 6DIG eliminating was fast, primarily in the urine and complete within 72 h. The effective whole-body absorbed dose for a complete scan with injection of 92.5 * 2 MBq was between 3 to 4 mSv. The second part of this thesis evaluated in human feasibility and reproducibility of the measurement technique validated in animal. The third part showed techniques used to allow human transfer of this method. The study protocol was applied on 12 subjects (healthy volunteers (n=6) and type 2 diabetic patients (n=6)). With a method adapted to measure in humans, we determined an

Insulin-Producing Cells Differentiated from Human Bone Marrow Mesenchymal Stem Cells In Vitro Ameliorate Streptozotocin-Induced Diabetic Hyperglycemia.

Directory of Open Access Journals (Sweden)

Ying Xin

Full Text Available The two major obstacles in the successful transplantation of islets for diabetes treatment are inadequate supply of insulin-producing tissue and immune rejection. Induction of the differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs into insulin-producing cells (IPCs for autologous transplantation may alleviate those limitations.hMSCs were isolated and induced to differentiate into IPCs through a three-stage differentiation protocol in a defined media with high glucose, nicotinamide, and exendin-4. The physiological characteristics and functions of IPCs were then evaluated. Next, about 3 × 10(6 differentiated cells were transplanted into the renal sub-capsular space of streptozotocin (STZ-induced diabetic nude mice. Graft survival and function were assessed by immunohistochemistry, TUNEL staining and measurements of blood glucose levels in the mice.The differentiated IPCs were characterized by Dithizone (DTZ positive staining, expression of pancreatic β-cell markers, and human insulin secretion in response to glucose stimulation. Moreover, 43% of the IPCs showed L-type Ca2+ channel activity and similar changes in intracellular Ca2+ in response to glucose stimulation as that seen in pancreatic β-cells in the process of glucose-stimulated insulin secretion. Transplantation of functional IPCs into the renal subcapsular space of STZ-induced diabetic nude mice ameliorated the hyperglycemia. Immunofluorescence staining revealed that transplanted IPCs sustainably expressed insulin, c-peptide, and PDX-1 without apparent apoptosis in vivo.IPCs derived from hMSCs in vitro can ameliorate STZ-induced diabetic hyperglycemia, which indicates that these hMSCs may be a promising approach to overcome the limitations of islet transplantation.

Protein Kinase-C Beta Contributes to Impaired Endothelial Insulin Signaling in Humans with Diabetes Mellitus

Science.gov (United States)

Tabit, Corey E; Shenouda, Sherene M; Holbrook, Monica; Fetterman, Jessica L; Kiani, Soroosh; Frame, Alissa A; Kluge, Matthew A; Held, Aaron; Dohadwala, Mustali; Gokce, Noyan; Farb, Melissa; Rosenzweig, James; Ruderman, Neil; Vita, Joseph A; Hamburg, Naomi M

2013-01-01

Background Abnormal endothelial function promotes atherosclerotic vascular disease in diabetes. Experimental studies indicate that disruption of endothelial insulin signaling through the activity of protein kinase C-β (PKCβ) and nuclear factor κB (NFκB) reduces nitric oxide availability. We sought to establish whether similar mechanisms operate in the endothelium in human diabetes mellitus. Methods and Results We measured protein expression and insulin response in freshly isolated endothelial cells from patients with Type 2 diabetes mellitus (n=40) and non-diabetic controls (n=36). Unexpectedly, we observed 1.7-fold higher basal endothelial nitric oxide synthase (eNOS) phosphorylation at serine 1177 in patients with diabetes (P=0.007) without a difference in total eNOS expression. Insulin stimulation increased eNOS phosphorylation in non-diabetic subjects but not in diabetic patients (P=0.003) consistent with endothelial insulin resistance. Nitrotyrosine levels were higher in diabetic patients indicating endothelial oxidative stress. PKCβ expression was higher in diabetic patients and was associated with lower flow-mediated dilation (r=−0.541, P=0.02) Inhibition of PKCβ with LY379196 reduced basal eNOS phosphorylation and improved insulin-mediated eNOS activation in patients with diabetes. Endothelial NFκB activation was higher in diabetes and was reduced with PKCβ inhibition. Conclusions We provide evidence for the presence of altered eNOS activation, reduced insulin action and inflammatory activation in the endothelium of patients with diabetes. Our findings implicate PKCβ activity in endothelial insulin resistance. PMID:23204109

Coordinated defects in hepatic long chain fatty acid metabolism and triglyceride accumulation contribute to insulin resistance in non-human primates.

Directory of Open Access Journals (Sweden)

Subhash Kamath

Full Text Available Non-alcoholic fatty liver disease (NAFLD is characterized by accumulation of triglycerides (TG in hepatocytes, which may also trigger cirrhosis. The mechanisms of NAFLD are not fully understood, but insulin resistance has been proposed as a key determinant.To determine the TG content and long chain fatty acyl CoA composition profile in liver from obese non-diabetic insulin resistant (IR and lean insulin sensitive (IS baboons in relation with hepatic and peripheral insulin sensitivity.Twenty baboons with varying grades of adiposity were studied. Hepatic (liver and peripheral (mainly muscle insulin sensitivity was measured with a euglycemic clamp and QUICKI. Liver biopsies were performed at baseline for TG content and LCFA profile by mass spectrometry, and histological analysis. Findings were correlated with clinical and biochemical markers of adiposity and insulin resistance.Obese IR baboons had elevated liver TG content compared to IS. Furthermore, the concentration of unsaturated (LC-UFA was greater than saturated (LC-SFA fatty acyl CoA in the liver. Interestingly, LC-FA UFA and SFA correlated with waist, BMI, insulin, NEFA, TG, QUICKI, but not M/I. Histological findings of NAFLD ranging from focal to diffuse hepatic steatosis were found in obese IR baboons.Liver TG content is closely related with both hepatic and peripheral IR, whereas liver LC-UFA and LC-SFA are closely related only with hepatic IR in non-human primates. Mechanisms leading to the accumulation of TG, LC-UFA and an altered UFA: LC-SFA ratio may play an important role in the pathophysiology of fatty liver disease in humans.

Understanding the structural differences between spherical and rod-shaped human insulin nanoparticles produced by supercritical fluids precipitation.

Science.gov (United States)

Park, Yeonju; Seo, Yongil; Chae, Boknam; Pyo, Dongjin; Chung, Hoeil; Hwang, Hyonseok; Jung, Young Mee

2015-02-02

In this study, the thermal denaturation mechanism and secondary structures of two types of human insulin nanoparticles produced by a process of solution-enhanced dispersion by supercritical fluids using dimethyl sulfoxide (DMSO) and ethanol (EtOH) solutions of insulin are investigated using spectroscopic approaches and molecular dynamics calculations. First, the temperature-dependent IR spectra of spherical and rod-shaped insulin nanoparticles prepared from DMSO and EtOH solution, respectively, are analyzed using principal component analysis (PCA) and 2D correlation spectroscopy to obtain a deeper understanding of the molecular structures and thermal behavior of the two insulin particle shapes. All-atom molecular dynamics (AAMD) calculations are performed to investigate the influence of the solvent molecules on the production of the insulin nanoparticles and to elucidate the geometric differences between the two types of nanoparticles. The results of the PCA, the 2D correlation spectroscopic analysis, and the AAMD calculations clearly reveal that the thermal denaturation mechanisms and the degrees of hydrogen bonding in the spherical and rod-shaped insulin nanoparticles are different. The polarity of the solvent might not alter the structure or function of the insulin produced, but the solvent polarity does influence the synthesis of different shapes of insulin nanoparticles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intranasal insulin modulates intrinsic reward and prefrontal circuitry of the human brain in lean women.

Science.gov (United States)

Kullmann, Stephanie; Frank, Sabine; Heni, Martin; Ketterer, Caroline; Veit, Ralf; Häring, Hans-Ulrich; Fritsche, Andreas; Preissl, Hubert

2013-01-01

There is accumulating evidence that food consumption is controlled by a wide range of brain circuits outside of the homeostatic system. Activation in these brain circuits may override the homeostatic system and also contribute to the enormous increase of obesity. However, little is known about the influence of hormonal signals on the brain's non-homeostatic system. Thus, selective insulin action in the brain was investigated by using intranasal application. We performed 'resting-state' functional magnetic resonance imaging in 17 healthy lean female subjects to assess intrinsic brain activity by fractional amplitude of low-frequency fluctuations (fALFF) before, 30 and 90 min after application of intranasal insulin. Here, we showed that insulin modulates intrinsic brain activity in the hypothalamus and orbitofrontal cortex. Furthermore, we could show that the prefrontal and anterior cingulate cortex response to insulin is associated with body mass index. This demonstrates that hormonal signals as insulin may reduce food intake by modifying the reward and prefrontal circuitry of the human brain, thereby potentially decreasing the rewarding properties of food. Due to the alarming increase in obesity worldwide, it is of great importance to identify neural mechanisms of interaction between the homeostatic and non-homeostatic system to generate new targets for obesity therapy. Copyright © 2012 S. Karger AG, Basel.

Insulin-producing Cells from Adult Human Bone Marrow Mesenchymal Stromal Cells Could Control Chemically Induced Diabetes in Dogs: A Preliminary Study.

Science.gov (United States)

Gabr, Mahmoud M; Zakaria, Mahmoud M; Refaie, Ayman F; Ismail, Amani M; Khater, Sherry M; Ashamallah, Sylvia A; Azzam, Maha M; Ghoneim, Mohamed A

2018-01-01

Ten mongrel dogs were used in this study. Diabetes was chemically induced in 7 dogs, and 3 dogs served as normal controls. For each diabetic dog, 5 million human bone marrow-derived mesenchymal stem cells/kg were differentiated to form insulin-producing cells using a trichostatin-based protocol. Cells were then loaded in 2 TheraCyte capsules which were transplanted under the rectus sheath. One dog died 4 d postoperatively from pneumonia. Six dogs were followed up with for 6 to 18 mo. Euglycemia was achieved in 4 dogs. Their glucose tolerance curves exhibited a normal pattern demonstrating that the encapsulated cells were glucose sensitive and insulin responsive. In the remaining 2 dogs, the fasting blood sugar levels were reduced but did not reach normal values. The sera of all transplanted dogs contained human insulin and C-peptide with a negligible amount of canine insulin. Removal of the transplanted capsules was followed by prompt return of diabetes. Intracytoplasmic insulin granules were seen by immunofluorescence in cells from the harvested capsules. Furthermore, all pancreatic endocrine genes were expressed. This study demonstrated that the TheraCyte capsule or a similar device can provide adequate immunoisolation, an important issue when stem cells are considered for the treatment of type 1 diabetes mellitus.

An Information Theoretical Analysis of Human Insulin-Glucose System Toward the Internet of Bio-Nano Things.

Science.gov (United States)

Abbasi, Naveed A; Akan, Ozgur B

2017-12-01

Molecular communication is an important tool to understand biological communications with many promising applications in Internet of Bio-Nano Things (IoBNT). The insulin-glucose system is of key significance among the major intra-body nanonetworks, since it fulfills metabolic requirements of the body. The study of biological networks from information and communication theoretical (ICT) perspective is necessary for their introduction in the IoBNT framework. Therefore, the objective of this paper is to provide and analyze for the first time in the literature, a simple molecular communication model of the human insulin-glucose system from ICT perspective. The data rate, channel capacity, and the group propagation delay are analyzed for a two-cell network between a pancreatic beta cell and a muscle cell that are connected through a capillary. The results point out a correlation between an increase in insulin resistance and a decrease in the data rate and channel capacity, an increase in the insulin transmission rate, and an increase in the propagation delay. We also propose applications for the introduction of the system in the IoBNT framework. Multi-cell insulin glucose system models may be based on this simple model to help in the investigation, diagnosis, and treatment of insulin resistance by means of novel IoBNT applications.

Insulin resistance is associated with MCP1-mediated macrophage accumulation in skeletal muscle in mice and humans.

Directory of Open Access Journals (Sweden)

David Patsouris

Full Text Available Inflammation is now recognized as a major factor contributing to type 2 diabetes (T2D. However, while the mechanisms and consequences associated with white adipose tissue inflammation are well described, very little is known concerning the situation in skeletal muscle. The aim of this study was to investigate, in vitro and in vivo, how skeletal muscle inflammation develops and how in turn it modulates local and systemic insulin sensitivity in different mice models of T2D and in humans, focusing on the role of the chemokine MCP1. Here, we found that skeletal muscle inflammation and macrophage markers are increased and associated with insulin resistance in mice models and humans. In addition, we demonstrated that intra-muscular TNFα expression is exclusively restricted to the population of intramuscular leukocytes and that the chemokine MCP1 was associated with skeletal muscle inflammatory markers in these models. Furthermore, we demonstrated that exposure of C2C12 myotubes to palmitate elevated the production of the chemokine MCP1 and that the muscle-specific overexpression of MCP1 in transgenic mice induced the local recruitment of macrophages and altered local insulin sensitivity. Overall our study demonstrates that skeletal muscle inflammation is clearly increased in the context of T2D in each one of the models we investigated, which is likely consecutive to the lipotoxic environment generated by peripheral insulin resistance, further increasing MCP1 expression in muscle. Consequently, our results suggest that MCP1-mediated skeletal muscle macrophages recruitment plays a role in the etiology of T2D.

Activation of IGF-1 and insulin signaling pathways ameliorate mitochondrial function and energy metabolism in Huntington's Disease human lymphoblasts.

Science.gov (United States)

Naia, Luana; Ferreira, I Luísa; Cunha-Oliveira, Teresa; Duarte, Ana I; Ribeiro, Márcio; Rosenstock, Tatiana R; Laço, Mário N; Ribeiro, Maria J; Oliveira, Catarina R; Saudou, Frédéric; Humbert, Sandrine; Rego, A Cristina

2015-02-01

Huntington's disease (HD) is an inherited neurodegenerative disease caused by a polyglutamine repeat expansion in the huntingtin protein. Mitochondrial dysfunction associated with energy failure plays an important role in this untreated pathology. In the present work, we used lymphoblasts obtained from HD patients or unaffected parentally related individuals to study the protective role of insulin-like growth factor 1 (IGF-1) versus insulin (at low nM) on signaling and metabolic and mitochondrial functions. Deregulation of intracellular signaling pathways linked to activation of insulin and IGF-1 receptors (IR,IGF-1R), Akt, and ERK was largely restored by IGF-1 and, at a less extent, by insulin in HD human lymphoblasts. Importantly, both neurotrophic factors stimulated huntingtin phosphorylation at Ser421 in HD cells. IGF-1 and insulin also rescued energy levels in HD peripheral cells, as evaluated by increased ATP and phosphocreatine, and decreased lactate levels. Moreover, IGF-1 effectively ameliorated O2 consumption and mitochondrial membrane potential (Δψm) in HD lymphoblasts, which occurred concomitantly with increased levels of cytochrome c. Indeed, constitutive phosphorylation of huntingtin was able to restore the Δψm in lymphoblasts expressing an abnormal expansion of polyglutamines. HD lymphoblasts further exhibited increased intracellular Ca(2+) levels before and after exposure to hydrogen peroxide (H2O2), and decreased mitochondrial Ca(2+) accumulation, being the later recovered by IGF-1 and insulin in HD lymphoblasts pre-exposed to H2O2. In summary, the data support an important role for IR/IGF-1R mediated activation of signaling pathways and improved mitochondrial and metabolic function in HD human lymphoblasts.

Human leukocyte antigen class II susceptibility conferring alleles among non-insulin dependent diabetes mellitus patients

International Nuclear Information System (INIS)

Tipu, H.N.; Ahmed, T.A.; Bashir, M.M.

2010-01-01

To determine the frequency of Human Leukocyte Antigen (HLA) class II susceptibility conferring alleles among type 2 Diabetes mellitus patients, in comparison with healthy controls. Cross-sectional comparative study. Patients with non-insulin dependent Diabetes mellitus meeting World Health Organization criteria were studied. These were compared with age and gender matched healthy control subjects. For each subject (patients as well as controls), DNA was extracted from ethylene diamine tetra-acetate sample and HLA class II DRB1 typing was carried out at allele group level (DRB1*01-DRB1*16) by sequence specific primers. Human leukocyte antigen DRB1 type was determined by agarose gel electrophoresis and results were recorded. Frequencies were determined as number of an allele divided by total number of alleles per group; p-value was computed using Pearson's chi-square test. Among the 100 patients, there were 63 males and 37 females with 68 controls. A total of 13 different HLA DRB1 alleles were detected, with DRB1*15 being the commonest in both the groups. The allele DRB1*13 had statistically significant higher frequency in patient group as compared to controls (p 0.005). HLA DRB1*13 was found with a significantly increased frequency in non-insulin dependent Diabetes mellitus. (author)

Characterization of lipid metabolism in insulin-sensitive adipocytes differentiated from immortalized human mesenchymal stem cells

International Nuclear Information System (INIS)

Prawitt, Janne; Niemeier, Andreas; Kassem, Moustapha; Beisiegel, Ulrike; Heeren, Joerg

2008-01-01

There is a great demand for cell models to study human adipocyte function. Here we describe the adipogenic differentiation of a telomerase-immortalized human mesenchymal stem cell line (hMSC-Tert) that maintains numerous features of terminally differentiated adipocytes even after prolonged withdrawal of the peroxisome proliferator activated receptor γ (PPARγ) agonist rosiglitazone. Differentiated hMSC-Tert developed the characteristic monolocular phenotype of mature adipocytes. The expression of adipocyte specific markers was highly increased during differentiation. Most importantly, the presence of the PPARγ agonist rosiglitazone was not required for the stable expression of lipoprotein lipase, adipocyte fatty acid binding protein and perilipin on mRNA and protein levels. Adiponectin expression was post-transcriptionally down-regulated in the absence of rosiglitazone. Insulin sensitivity as measured by insulin-induced phosphorylation of Akt and S6 ribosomal protein was also independent of rosiglitazone. In addition to commonly used adipogenic markers, we investigated further PPARγ-stimulated proteins with a role in lipid metabolism. We observed an increase of lipoprotein receptor (VLDLR, LRP1) and apolipoprotein E expression during differentiation. Despite this increased expression, the receptor-mediated endocytosis of lipoproteins was decreased in differentiated adipocytes, suggesting that these proteins may have an additional function in adipose tissue beyond lipoprotein uptake

Treatment with insulin (analogues) and breast cancer risk in diabetics; a systematic review and meta-analysis of in vitro, animal and human evidence

DEFF Research Database (Denmark)

Bronsveld, Heleen K; ter Braak, Bas; Karlstad, Øystein

2015-01-01

INTRODUCTION: Several studies have suggested that anti-diabetic insulin analogue treatment might increase cancer risk. The aim of this study was to review the postulated association between insulin and insulin analogue treatment and breast cancer development, and plausible mechanisms. METHOD......: A systematic literature search was performed on breast cell-line, animal and human studies using the key words 'insulin analogue' and 'breast neoplasia' in MEDLINE at PubMed, EMBASE, and ISI Web of Science databases. A quantitative and qualitative review was performed on the epidemiological data; due...

Evalation of a radioimmunoassay for somatomedin-C/insulin-like growth factor I (Sm-C/IGF-I) in human plasma

International Nuclear Information System (INIS)

Giannella-Neto, D.; Cavaleiro, A.M.; Wajchenberg, B.L.; Sadoyama, R.; Spencer, E.M.

1990-01-01

In the present report the authors describe the development of a very sensitive radioimmunoassay for the quantitativew determination of human somatomedin-C/insulin-like growth factor I in plasma samples extracted by an acid-ethanol procedure. (RB). 22 refs.; 1 fig.; 1 tab

Insulin resistance alters islet morphology in nondiabetic humans

DEFF Research Database (Denmark)

Mezza, Teresa; Muscogiuri, Giovanna; Sorice, Gian Pio

2014-01-01

Type 2 diabetes is characterized by poor glucose uptake in metabolic tissues and manifests when insulin secretion fails to cope with worsening insulin resistance. In addition to its effects on skeletal muscle, liver, and adipose tissue metabolism, it is evident that insulin resistance also affects...... pancreatic β-cells. To directly examine the alterations that occur in islet morphology as part of an adaptive mechanism to insulin resistance, we evaluated pancreas samples obtained during pancreatoduodenectomy from nondiabetic subjects who were insulin-resistant or insulin-sensitive. We also compared...... insulin sensitivity, insulin secretion, and incretin levels between the two groups. We report an increased islet size and an elevated number of β- and α-cells that resulted in an altered β-cell-to-α-cell area in the insulin- resistant group. Our data in this series of studies suggest that neogenesis from...

Synthesis of (/sup 3/H-Tyr/sup B26/)-human insulin by enzymic semisynthesis

Energy Technology Data Exchange (ETDEWEB)

Haensicke, A; Kaufmann, K D; Beyermann, M; Oehlke, J; Kertscher, U; Bienert, M; Niedrich, H; Mittag, E; Bespalova, Zh D; Titov, M I

1988-11-01

A procedure is described for tritium labelling of human insulin in position Tyr/sup B26/ by means of trypsin catalyzed condensation of DiBoc-DOI with (N/sup /epsilon//-Boc, /sup 3/H-Tyr/sup B26/)-IOP, subsequent deprotection and purification by HPLC. The tritium labelling of the octapeptide was accomplished by dehalotritiation of the corresponding Dit/sup B26/-octapeptide which was obtained both by iodination of N/sup /epsilon//-Boc-IOP and by total synthesis. (author). 2 figs., 1 tab., 17 refs.

High oxygen condition facilitates the differentiation of mouse and human pluripotent stem cells into pancreatic progenitors and insulin-producing cells.

Science.gov (United States)

Hakim, Farzana; Kaitsuka, Taku; Raeed, Jamiruddin Mohd; Wei, Fan-Yan; Shiraki, Nobuaki; Akagi, Tadayuki; Yokota, Takashi; Kume, Shoen; Tomizawa, Kazuhito

2014-04-04

Pluripotent stem cells have potential applications in regenerative medicine for diabetes. Differentiation of stem cells into insulin-producing cells has been achieved using various protocols. However, both the efficiency of the method and potency of differentiated cells are insufficient. Oxygen tension, the partial pressure of oxygen, has been shown to regulate the embryonic development of several organs, including pancreatic β-cells. In this study, we tried to establish an effective method for the differentiation of induced pluripotent stem cells (iPSCs) into insulin-producing cells by culturing under high oxygen (O2) conditions. Treatment with a high O2 condition in the early stage of differentiation increased insulin-positive cells at the terminus of differentiation. We found that a high O2 condition repressed Notch-dependent gene Hes1 expression and increased Ngn3 expression at the stage of pancreatic progenitors. This effect was caused by inhibition of hypoxia-inducible factor-1α protein level. Moreover, a high O2 condition activated Wnt signaling. Optimal stage-specific treatment with a high O2 condition resulted in a significant increase in insulin production in both mouse embryonic stem cells and human iPSCs and yielded populations containing up to 10% C-peptide-positive cells in human iPSCs. These results suggest that culturing in a high O2 condition at a specific stage is useful for the efficient generation of insulin-producing cells.

Human ketone body production and utilization studied using tracer techniques: Regulation by free fatty acids, insulin, catecholamines, and thyroid hormones

Energy Technology Data Exchange (ETDEWEB)

Keller, U.; Lustenberger, M.; Mueller-Brand, J.G.; Gerber, P.P.; Stauffacher, W.

1989-05-01

Ketone body concentrations fluctuate markedly during physiological and pathological conditions. Tracer techniques have been developed in recent years to study production, utilization, and the metabolic clearance rate of ketone bodies. This review describes data on the roles of insulin, catecholamines, and thyroid hormones in the regulation of ketone body kinetics. The data indicate that insulin lowers ketone body concentrations by three independent mechanisms: first, it inhibits lipolysis, and thus lowers free fatty acid availability for ketogenesis; second, it restrains ketone body production within the liver; third, it enhances peripheral ketone body utilization. To assess these effects in humans in vivo, experimental models were developed to study insulin effects with controlled concentrations of free fatty acids, insulin, glucagon, and ketone bodies. Presently available data also support an important role of catecholamines in increasing ketone body concentrations. Evidence was presented that norepinephrine increases ketogenesis not only by stimulating lipolysis, and thus releasing free fatty acids, but also by increasing intrahepatic ketogenesis. Thyroid hormone availability was associated with lipolysis and ketogenesis. Ketone body concentrations after an overnight fast were only modestly elevated in hyperthyroidism resulting from increased peripheral ketone body clearance. There was a significant correlation between serum triiodothyronine levels and the ketone body metabolic clearance rate. Thus, ketone body homeostasis in human subjects resulted from the interaction of hormones such as insulin, catecholamines, and thyroid hormones regulating lipolysis, intrahepatic ketogenesis, and peripheral ketone body utilization. 58 references.

Human ketone body production and utilization studied using tracer techniques: Regulation by free fatty acids, insulin, catecholamines, and thyroid hormones

International Nuclear Information System (INIS)

Keller, U.; Lustenberger, M.; Mueller-Brand, J.G.; Gerber, P.P.; Stauffacher, W.

1989-01-01

Ketone body concentrations fluctuate markedly during physiological and pathological conditions. Tracer techniques have been developed in recent years to study production, utilization, and the metabolic clearance rate of ketone bodies. This review describes data on the roles of insulin, catecholamines, and thyroid hormones in the regulation of ketone body kinetics. The data indicate that insulin lowers ketone body concentrations by three independent mechanisms: first, it inhibits lipolysis, and thus lowers free fatty acid availability for ketogenesis; second, it restrains ketone body production within the liver; third, it enhances peripheral ketone body utilization. To assess these effects in humans in vivo, experimental models were developed to study insulin effects with controlled concentrations of free fatty acids, insulin, glucagon, and ketone bodies. Presently available data also support an important role of catecholamines in increasing ketone body concentrations. Evidence was presented that norepinephrine increases ketogenesis not only by stimulating lipolysis, and thus releasing free fatty acids, but also by increasing intrahepatic ketogenesis. Thyroid hormone availability was associated with lipolysis and ketogenesis. Ketone body concentrations after an overnight fast were only modestly elevated in hyperthyroidism resulting from increased peripheral ketone body clearance. There was a significant correlation between serum triiodothyronine levels and the ketone body metabolic clearance rate. Thus, ketone body homeostasis in human subjects resulted from the interaction of hormones such as insulin, catecholamines, and thyroid hormones regulating lipolysis, intrahepatic ketogenesis, and peripheral ketone body utilization. 58 references

Protein kinase C is differentially regulated by thrombin, insulin, and epidermal growth factor in human mammary tumor cells

Energy Technology Data Exchange (ETDEWEB)

Gomez, M.L.; Tellez-Inon, M.T. (Instituto de Ingenieria Genetica y Biologia Molecular, Buenos Aires (Argentina)); Medrano, E.E.; Cafferatta, E.G.A. (Instituto de Investigaciones Bioquimicas Fundacion Campomar, Buenos Aires (Argentina))

1988-03-01

The exposure of serum-deprived mammary tumor cells MCF-7 and T-47D to insulin, thrombin, and epidermal growth factor (EGF) resulted in dramatic modifications in the activity and in the translocation capacity of protein kinase C from cytosol to membrane fractions. Insulin induces a 600% activation of the enzyme after 5 h of exposure to the hormone in MCF-7 cells; thrombin either activates (200% in MCF-7) or down-regulates (in T-47D), and EGF exerts only a moderate effect. Thus, the growth factors studied modulate differentially the protein kinase C activity in human mammary tumor cells. The physiological significance of the results obtained are discussed in terms of the growth response elicited by insulin, thrombin, and EGF.

Cholinergic signaling mediates the effects of xenin-25 on secretion of pancreatic polypeptide but not insulin or glucagon in humans with impaired glucose tolerance.

Directory of Open Access Journals (Sweden)

Songyan Wang

Full Text Available We previously demonstrated that infusion of an intestinal peptide called xenin-25 (Xen amplifies the effects of glucose-dependent insulinotropic polypeptide (GIP on insulin secretion rates (ISRs and plasma glucagon levels in humans. However, these effects of Xen, but not GIP, were blunted in humans with type 2 diabetes. Thus, Xen rather than GIP signaling to islets fails early during development of type 2 diabetes. The current crossover study determines if cholinergic signaling relays the effects of Xen on insulin and glucagon release in humans as in mice. Fasted subjects with impaired glucose tolerance were studied. On eight separate occasions, each person underwent a single graded glucose infusion- two each with infusion of albumin, Xen, GIP, and GIP plus Xen. Each infusate was administered ± atropine. Heart rate and plasma glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide (PP levels were measured. ISRs were calculated from C-peptide levels. All peptides profoundly increased PP responses. From 0 to 40 min, peptide(s infusions had little effect on plasma glucose concentrations. However, GIP, but not Xen, rapidly and transiently increased ISRs and glucagon levels. Both responses were further amplified when Xen was co-administered with GIP. From 40 to 240 min, glucose levels and ISRs continually increased while glucagon concentrations declined, regardless of infusate. Atropine increased resting heart rate and blocked all PP responses but did not affect ISRs or plasma glucagon levels during any of the peptide infusions. Thus, cholinergic signaling mediates the effects of Xen on insulin and glucagon release in mice but not humans.

Differential responsiveness of luteinized human granulosa cells to gonadotropins and insulin-like growth factor I for induction of aromatase activity

International Nuclear Information System (INIS)

Christman, G.M.; Randolph, J.F. Jr.; Peegel, H.; Menon, K.M.

1991-01-01

The objective of this study was to examine the in vitro responsiveness of cultured luteinized human granulosa cells over time to insulin-like growth factor 1 (IGF-1), human follicle-stimulating hormone (FSH), and human chorionic gonadotropin (hCG) for the induction of aromatase activity. Granulosa cells were retrieved from preovulatory follicles in patients undergoing in vitro fertilization. Cells were cultured for a period of 72 hours or 10 days. The ability of hCG, human FSH, and/or IGF-I to induce aromatase activity was assayed by the stereospecific release of tritium from [1B-3H]androstenedione. Short-term cultures (72 hours) demonstrated a marked rise in aromatase activity in response to human FSH and IGF-I, whereas a smaller response to hCG was observed. In contrast, 10-day cultures demonstrated responsiveness predominantly to hCG rather than human FSH for the induction of aromatase activity with no remarkable effect of IGF-I. Luteinized human granulosa cells undergo a transformation from an initial human FSH and IGF-I responsive state to an hCG responsive state in long-term cultures

A Branched-Chain Amino Acid-Related Metabolic Signature that Differentiates Obese and Lean Humans and Contributes to Insulin Resistance

Science.gov (United States)

Newgard, Christopher B; An, Jie; Bain, James R; Muehlbauer, Michael J; Stevens, Robert D; Lien, Lillian F; Haqq, Andrea M; Shah, Svati H.; Arlotto, Michelle; Slentz, Cris A; Rochon, James; Gallup, Dianne; Ilkayeva, Olga; Wenner, Brett R; Yancy, William E; Eisenson, Howard; Musante, Gerald; Surwit, Richard; Millington, David S; Butler, Mark D; Svetkey, Laura P

2009-01-01

Summary Metabolomic profiling of obese versus lean humans reveals a branched-chain amino acid (BCAA)-related metabolite signature that is suggestive of increased catabolism of BCAA and correlated with insulin resistance. To test its impact on metabolic homeostasis, we fed rats on high-fat (HF), HF with supplemented BCAA (HF/BCAA) or standard chow (SC) diets. Despite having reduced food intake and weight gain equivalent to the SC group, HF/BCAA rats were equally insulin resistant as HF rats. Pair-feeding of HF diet to match the HF/BCAA animals or BCAA addition to SC diet did not cause insulin resistance. Insulin resistance induced by HF/BCAA feeding was accompanied by chronic phosphorylation of mTOR, JNK, and IRS1(ser307), accumulation of multiple acylcarnitines in muscle, and was reversed by the mTOR inhibitor, rapamycin. Our findings show that in the context of a poor dietary pattern that includes high fat consumption, BCAA contributes to development of obesity-associated insulin resistance. PMID:19356713

Structure of human insulin monomer in water/acetonitrile solution

International Nuclear Information System (INIS)

Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta; Tarnowska, Anna; Kawecki, Robert; Kozerski, Lech

2008-01-01

Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H 2 O/CD 3 CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER V C), or including a generalized Born solvent model (AMBER G B)

Maternal serum placental growth hormone, but not human placental lactogen or insulin growth factor-1, is positively associated with fetal growth in the first half of pregnancy

DEFF Research Database (Denmark)

Pedersen, N G; Juul, A; Christiansen, M

2010-01-01

To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin-like growth factor-1 (IGF-1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy.......To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin-like growth factor-1 (IGF-1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy....

Inflammation and insulin resistance induced by trans-10, cis-12 conjugated linoleic acid depend on intracellular calcium levels in primary cultures of human adipocytes

DEFF Research Database (Denmark)

Kennedy, Arion; Martinez, Kristina; Chung, Soonkyu

2010-01-01

We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) induced inflammation and insulin resistance in primary human adipocytes by activating nuclear factor kappaB (NFkappaB) and extracellular signal-related kinase (ERK) signaling. In this study, we demonstrated...... that the initial increase in intracellular calcium ([Ca2+]i) mediated by 10,12 CLA was attenuated by TMB-8, an inhibitor of calcium release from the endoplasmic reticulum (ER), by BAPTA, an intracellular calcium chelator, and by D609, a phospholipase C (PLC) inhibitor. Moreover, BAPTA, TMB-8, and D609 attenuated......, and suppression of peroxisome proliferator activated receptor gamma protein levels and insulin-stimulated glucose uptake. These data suggest that 10,12 CLA increases inflammation and insulin resistance in human adipocytes, in part by increasing [Ca2+]i levels, particularly calcium from the ER....

Interacting with the Human Insulin Receptor

DEFF Research Database (Denmark)

Kidmose, Rune Thomas; Andersen, Gregers Rom

2016-01-01

Insulin is an essential regulator of glucose homeostasis. In this issue of Structure, Croll et al. (2016) reports a significantly improved model of the Fab-complexed IR ectodomain refined against a dataset extending to 3.3 Å.......Insulin is an essential regulator of glucose homeostasis. In this issue of Structure, Croll et al. (2016) reports a significantly improved model of the Fab-complexed IR ectodomain refined against a dataset extending to 3.3 Å....

Ultra-high resolution X-ray structures of two forms of human recombinant insulin at 100 K.

Science.gov (United States)

Lisgarten, David R; Palmer, Rex A; Lobley, Carina M C; Naylor, Claire E; Chowdhry, Babur Z; Al-Kurdi, Zakieh I; Badwan, Adnan A; Howlin, Brendan J; Gibbons, Nicholas C J; Saldanha, José W; Lisgarten, John N; Basak, Ajit K

2017-08-01

The crystal structure of a commercially available form of human recombinant (HR) insulin, Insugen (I), used in the treatment of diabetes has been determined to 0.92 Å resolution using low temperature, 100 K, synchrotron X-ray data collected at 16,000 keV (λ = 0.77 Å). Refinement carried out with anisotropic displacement parameters, removal of main-chain stereochemical restraints, inclusion of H atoms in calculated positions, and 220 water molecules, converged to a final value of R = 0.1112 and R free  = 0.1466. The structure includes what is thought to be an ordered propanol molecule (POL) only in chain D(4) and a solvated acetate molecule (ACT) coordinated to the Zn atom only in chain B(2). Possible origins and consequences of the propanol and acetate molecules are discussed. Three types of amino acid representation in the electron density are examined in detail: (i) sharp with very clearly resolved features; (ii) well resolved but clearly divided into two conformations which are well behaved in the refinement, both having high quality geometry; (iii) poor density and difficult or impossible to model. An example of type (ii) is observed for the intra-chain disulphide bridge in chain C(3) between Sγ6-Sγ11 which has two clear conformations with relative refined occupancies of 0.8 and 0.2, respectively. In contrast the corresponding S-S bridge in chain A(1) shows one clearly defined conformation. A molecular dynamics study has provided a rational explanation of this difference between chains A and C. More generally, differences in the electron density features between corresponding residues in chains A and C and chains B and D is a common observation in the Insugen (I) structure and these effects are discussed in detail. The crystal structure, also at 0.92 Å and 100 K, of a second commercially available form of human recombinant insulin, Intergen (II), deposited in the Protein Data Bank as 3W7Y which remains otherwise unpublished is compared here

Internalization and localization of basal insulin peglispro in cells.

Science.gov (United States)

Moyers, Julie S; Volk, Catherine B; Cao, Julia X C; Zhang, Chen; Ding, Liyun; Kiselyov, Vladislav V; Michael, M Dodson

2017-10-15

Basal insulin peglispro (BIL) is a novel, PEGylated insulin lispro that has a large hydrodynamic size compared with insulin lispro. It has a prolonged duration of action, which is related to a delay in insulin absorption and a reduction in clearance. Given the different physical properties of BIL compared with native insulin and insulin lispro, it is important to assess the cellular internalization characteristics of the molecule. Using immunofluorescent confocal imaging, we compared the cellular internalization and localization patterns of BIL, biosynthetic human insulin, and insulin lispro. We assessed the effects of BIL on internalization of the insulin receptor (IR) and studied cellular clearance of BIL. Co-localization studies using antibodies to either insulin or PEG, and the early endosomal marker EEA1 showed that the overall internalization and subcellular localization pattern of BIL was similar to that of human insulin and insulin lispro; all were rapidly internalized and co-localized with EEA1. During ligand washout for 4 h, concomitant loss of insulin, PEG methoxy group, and PEG backbone immunostaining was observed for BIL, similar to the loss of insulin immunostaining observed for insulin lispro and human insulin. Co-localization studies using an antibody to the lysosomal marker LAMP1 did not reveal evidence of lysosomal localization for insulin lispro, human insulin, BIL, or PEG using either insulin or PEG immunostaining reagents. BIL and human insulin both induced rapid phosphorylation and internalization of human IR. Our findings show that treatment of cells with BIL stimulates internalization and localization of IR to early endosomes. Both the insulin and PEG moieties of BIL undergo a dynamic cellular process of rapid internalization and transport to early endosomes followed by loss of cellular immunostaining in a manner similar to that of insulin lispro and human insulin. The rate of clearance for the insulin lispro portion of BIL was slower than

Transforming growth factor-beta1 stimulates the production of insulin-like growth factor-I and insulin-like growth factor-binding protein-3 in human bone marrow stromal osteoblast progenitors

DEFF Research Database (Denmark)

Kveiborg, Marie; Flyvbjerg, Allan; Eriksen, E F

2001-01-01

While transforming growth factor-beta1 (TGF-beta1) regulates proliferation and differentiation of human osteoblast precursor cells, the mechanisms underlying these effects are not known. Several hormones and locally acting growth factors regulate osteoblast functions through changes in the insulin......-like growth factors (IGFs) and IGF-binding proteins (IGFBPs). Thus, we studied the effects of TGF-beta1 on IGFs and IGFBPs in human marrow stromal (hMS) osteoblast precursor cells. TGF-beta1 increased the steady-state mRNA level of IGF-I up to 8.5+/-0.6-fold (P...

Generation of insulin-producing cells from human bone marrow-derived mesenchymal stem cells: comparison of three differentiation protocols.

Science.gov (United States)

Gabr, Mahmoud M; Zakaria, Mahmoud M; Refaie, Ayman F; Khater, Sherry M; Ashamallah, Sylvia A; Ismail, Amani M; El-Badri, Nagwa; Ghoneim, Mohamed A

2014-01-01

Many protocols were utilized for directed differentiation of mesenchymal stem cells (MSCs) to form insulin-producing cells (IPCs). We compared the relative efficiency of three differentiation protocols. Human bone marrow-derived MSCs (HBM-MSCs) were obtained from three insulin-dependent type 2 diabetic patients. Differentiation into IPCs was carried out by three protocols: conophylline-based (one-step protocol), trichostatin-A-based (two-step protocol), and β -mercaptoethanol-based (three-step protocol). At the end of differentiation, cells were evaluated by immunolabeling for insulin production, expression of pancreatic endocrine genes, and release of insulin and c-peptide in response to increasing glucose concentrations. By immunolabeling, the proportion of generated IPCs was modest ( ≃ 3%) in all the three protocols. All relevant pancreatic endocrine genes, insulin, glucagon, and somatostatin, were expressed. There was a stepwise increase in insulin and c-peptide release in response to glucose challenge, but the released amounts were low when compared with those of pancreatic islets. The yield of functional IPCs following directed differentiation of HBM-MSCs was modest and was comparable among the three tested protocols. Protocols for directed differentiation of MSCs need further optimization in order to be clinically meaningful. To this end, addition of an extracellular matrix and/or a suitable template should be attempted.

Expression and functional assessment of candidate type 2 diabetes susceptibility genes identify four new genes contributing to human insulin secretion

Directory of Open Access Journals (Sweden)

Fatou K. Ndiaye

2017-06-01

Full Text Available Objectives: Genome-wide association studies (GWAS have identified >100 loci independently contributing to type 2 diabetes (T2D risk. However, translational implications for precision medicine and for the development of novel treatments have been disappointing, due to poor knowledge of how these loci impact T2D pathophysiology. Here, we aimed to measure the expression of genes located nearby T2D associated signals and to assess their effect on insulin secretion from pancreatic beta cells. Methods: The expression of 104 candidate T2D susceptibility genes was measured in a human multi-tissue panel, through PCR-free expression assay. The effects of the knockdown of beta-cell enriched genes were next investigated on insulin secretion from the human EndoC-βH1 beta-cell line. Finally, we performed RNA-sequencing (RNA-seq so as to assess the pathways affected by the knockdown of the new genes impacting insulin secretion from EndoC-βH1, and we analyzed the expression of the new genes in mouse models with altered pancreatic beta-cell function. Results: We found that the candidate T2D susceptibility genes' expression is significantly enriched in pancreatic beta cells obtained by laser capture microdissection or sorted by flow cytometry and in EndoC-βH1 cells, but not in insulin sensitive tissues. Furthermore, the knockdown of seven T2D-susceptibility genes (CDKN2A, GCK, HNF4A, KCNK16, SLC30A8, TBC1D4, and TCF19 with already known expression and/or function in beta cells changed insulin secretion, supporting our functional approach. We showed first evidence for a role in insulin secretion of four candidate T2D-susceptibility genes (PRC1, SRR, ZFAND3, and ZFAND6 with no previous knowledge of presence and function in beta cells. RNA-seq in EndoC-βH1 cells with decreased expression of PRC1, SRR, ZFAND6, or ZFAND3 identified specific gene networks related to T2D pathophysiology. Finally, a positive correlation between the expression of Ins2 and the

Insulin aspart in diabetic pregnancy

DEFF Research Database (Denmark)

Mathiesen, Elisabeth R

2008-01-01

in insulin requirements during pregnancy necessitate short-acting insulins for postprandial control of hyperglycemia. The fast-acting insulin analogue insulin aspart has been tested in a large, randomized trial of pregnant women with Type 1 diabetes and offers benefits in control of postprandial...... hyperglycemia with a tendency towards fewer episodes of severe hypoglycemia compared with human insulin. Treatment with insulin aspart was associated with a tendency toward fewer fetal losses and preterm deliveries than treatment with human insulin. Insulin aspart could not be detected in the fetal circulation...... and no increase in insulin antibodies was found. Thus, the use of insulin aspart in pregnancy is regarded safe....

Differentiation of Human Mesenchymal Stem Cells into Insulin Producing Cells by Using A Lentiviral Vector Carrying PDX1.

Science.gov (United States)

Allahverdi, Amir; Abroun, Saied; Jafarian, Arefeh; Soleimani, Masoud; Taghikhani, Mohammad; Eskandari, Fatemeh

2015-01-01

Type I diabetes is an immunologically-mediated devastation of insulin producing cells (IPCs) in the pancreatic islet. Stem cells that produce β-cells are a new promising tool. Adult stem cells such as mesenchymal stem cells (MSCs) are self renewing multi potent cells showing capabilities to differentiate into ectodermal, mesodermal and endodermal tissues. Pancreatic and duodenal homeobox factor 1 (PDX1) is a master regulator gene required for embryonic development of the pancreas and is crucial for normal pancreatic islets activities in adults. We induced the over-expression of the PDX1 gene in human bone marrow MSCs (BM-MSCs) by Lenti-PDX1 in order to generate IPCs. Next, we examine the ability of the cells by measuring insulin/c-peptide production and INSULIN and PDX1 gene expressions. After transduction, MSCs changed their morphology at day 5 and gradually differentiated into IPCs. INSULIN and PDX1 expressions were confirmed by real time polymerase chain reaction (RT-PCR) and immunostaining. IPC secreted insulin and C-peptide in the media that contained different glucose concentrations. MSCs differentiated into IPCs by genetic manipulation. Our result showed that lentiviral vectors could deliver PDX1 gene to MSCs and induce pancreatic differentiation.

Human placental growth hormone, insulin-like growth factor I and -II, and insulin requirements during pregnancy in type 1 diabetes

DEFF Research Database (Denmark)

Fuglsang, Jens; Lauszus, Finn; Flyvbjerg, Allan

2003-01-01

between hPGH and IGF-I in type 1 diabetes mellitus has not been investigated thoroughly. Furthermore, hPGH may be involved in the development of insulin resistance during pregnancy. In this prospective, longitudinal study, 51 type 1 diabetic subjects were followed with repeated blood sampling during...... pregnancy in type 1 diabetic subjects could not be related to hPGH levels.......Human placental GH (hPGH) replaces pituitary GH during pregnancy. hPGH is correlated to serum IGF-I in normal pregnancies and in pregnancies complicated by fetoplacental disorders. In gestational diabetes and type 2 diabetes no correlation between hPGH and IGF-I has been found. The relationship...

Label-free detection of insulin and glucagon within human islets of Langerhans using Raman spectroscopy.

Directory of Open Access Journals (Sweden)

Janneke Hilderink

Full Text Available Intrahepatic transplantation of donor islets of Langerhans is a promising therapy for patients with type 1 diabetes. It is of critical importance to accurately monitor islet quality before transplantation, which is currently done by standard histological methods that are performed off-line and require extensive sample preparation. As an alternative, we propose Raman spectroscopy which is a non-destructive and label-free technique that allows continuous real-time monitoring of the tissue to study biological changes as they occur. By performing Raman spectroscopic measurements on purified insulin and glucagon, we showed that the 520 cm(-1 band assigned to disulfide bridges in insulin, and the 1552 cm(-1 band assigned to tryptophan in glucagon are mutually exclusive and could therefore be used as indirect markers for the label-free distinction between both hormones. High-resolution hyperspectral Raman imaging for these bands showed the distribution of disulfide bridges and tryptophan at sub-micrometer scale, which correlated with the location of insulin and glucagon as revealed by conventional immunohistochemistry. As a measure for this correlation, quantitative analysis was performed comparing the Raman images with the fluorescence images, resulting in Dice coefficients (ranging between 0 and 1 of 0.36 for insulin and 0.19 for glucagon. Although the use of separate microscope systems with different spatial resolution and the use of indirect Raman markers cause some image mismatch, our findings indicate that Raman bands for disulfide bridges and tryptophan can be used as distinctive markers for the label-free detection of insulin and glucagon in human islets of Langerhans.

Effect of iodination site on binding of radiolabeled ligand by insulin antibodies and insulin autoantibodies

International Nuclear Information System (INIS)

Diaz, J.L.; Wilkin, T.J.

1988-01-01

Four human insulins and four porcine insulins, each monoiodinated to the same specific activity at one of the four tyrosine residues (A14, A19, B16, B26) and purified by reversed-phase liquid chromatography, were tested in a radiobinding assay against a panel of insulin-antibody (IA)-positive sera from 10 insulin-treated diabetics and insulin-autoantibody-positive (IAA) sera from 10 nondiabetics. Of the 10 IAA-positive sera, five were fully cross reactive with both insulin species, and five were specific for human insulin. The rank order of binding of sera with the four ligands from each species was random for IA (mean rank values of 1.9 for A14, 2.0 for A19, 2.5 for B16, and 3.6 for B26 from a possible ranking range of 1 to 4), but more consistent for non-human-insulin-specific IAA (mean rank values 1.3 for A14, 3.8 for A19, 1.7 for B16, and 3.2 for B26 for labeled human insulins; 1.2 for A14, 4.0 for A19, 1.8 for B16, and 3.0 for B26 for labeled porcine insulins). The rank order of binding was virtually uniform for human-insulin-specific IAA (mean values 1.2 for A14, 3.0 for A19, 1.8 for B16, and 4.0 for B26). The influence of iodination site on the binding of labeled insulin appears to be dependent on the proximity of the labeled tyrosine to the antibody binding site and the clonal diversity, or restriction, of insulin-binding antibodies in the test serum. When IA and IAA are measured, the implications of this study regarding the choice of assay ligand may be important

Structure of human insulin monomer in water/acetonitrile solution

Energy Technology Data Exchange (ETDEWEB)

Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta [National Medicines Institute (Poland); Tarnowska, Anna; Kawecki, Robert [Institute of Organic Chemistry Polish Academy of Sciences (Poland); Kozerski, Lech [National Medicines Institute (Poland)], E-mail: lkoz@icho.edu.pl

2008-01-15

Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H{sub 2}O/CD{sub 3}CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER{sub V}C), or including a generalized Born solvent model (AMBER{sub G}B)

Direct radioimmunoassay of proinsulin and insulin in human plasma by the chromatographic technique

Energy Technology Data Exchange (ETDEWEB)

Megahed, Y M; Abdel-Wahab, M F; El-Shawarbie, K; Sadek, S; Amer, M S [Atomic Energy Establishment, Cairo (Egypt). Radioisotope Department; Ain Shams Univ., Cairo (Egypt). Faculty of Medicine)

1976-04-01

Specific method for direct radioimmunoassay of IRP and IRI separately in human plasma has been described. The method is used for extraction of total insulin and separation of IRP from IRI by paper chromatography to be assayed separately. The separation of the two components is identified and confirmed by column chromatography, paper chromatography and ultraviolet spectral analysis in comparison with the standard compounds. 134 plasma samples of different cases were investigated for the determination of IRI, IRP and IRT. Out of these 39 were normals, 16 normal obes, 21 juvinil diabetes, 18 overt adult diabetes, 10 recent adult diabetes, 12 hypothyroidism and 18 bilharzial hepatosplenomegaly. They were used to evaluate the test levels in comparison with blood sugar concentration.

TXNIP regulates peripheral glucose metabolism in humans

DEFF Research Database (Denmark)

Parikh, Hemang; Carlsson, Emma; Chutkow, William A

2007-01-01

combined human insulin/glucose clamp physiological studies with genome-wide expression profiling to identify thioredoxin interacting protein (TXNIP) as a gene whose expression is powerfully suppressed by insulin yet stimulated by glucose. In healthy individuals, its expression was inversely correlated...... expression is consistently elevated in the muscle of prediabetics and diabetics, although in a panel of 4,450 Scandinavian individuals, we found no evidence for association between common genetic variation in the TXNIP gene and T2DM. CONCLUSIONS: TXNIP regulates both insulin-dependent and insulin......-independent pathways of glucose uptake in human skeletal muscle. Combined with recent studies that have implicated TXNIP in pancreatic beta-cell glucose toxicity, our data suggest that TXNIP might play a key role in defective glucose homeostasis preceding overt T2DM....

Human umbilical cord-derived mesenchymal stem cells ameliorate insulin resistance by suppressing NLRP3 inflammasome-mediated inflammation in type 2 diabetes rats

Directory of Open Access Journals (Sweden)

Xiaoya Sun

2017-11-01

Full Text Available Abstract Background Insulin resistance is one of the most common and important pathological features of type 2 diabetes (T2D. Recently, insulin resistance is increasingly considered to be associated with systemic chronic inflammation. Elevated levels of tumor necrosis factor (TNF-α and interleukin (IL-1β in blood are predictive indicators of the development of T2D. Mesenchymal stem cell (MSC-based therapies have been proven to have potential immunomodulation and anti-inflammatory properties through their paracrine effects; however, the mechanism for the anti-inflammatory effect of MSCs in enhancing insulin sensitivity is still uncertain. Methods In the present experiment, we used HepG2 cells, a human hepatoma cell line, and a MSC-HepG2 transwell culturing system to investigate the anti-inflammatory mechanism of human umbilical cord-derived MSCs (UC-MSCs under palmitic acid (PA and lipopolysaccharide (LPS-induced insulin resistance in vitro. Insulin resistance was confirmed by glycogen assay kit and glucose assay kit. Inflammatory factor release was detected by ELISA, gene expression was tested by quantitative real-time PCR, and insulin signaling activation was determined by western blotting analysis. The changes of inflammatory factors and insulin signaling protein were also tested in T2D rats injected with UC-MSCs. Results Treating HepG2 cells with PA–LPS caused NLRP3 inflammation activation, including overexpression of NLRP3 and caspase-1, and overproduction of IL-1β and IL-18 as well as TNF-α from HepG2 cells. The elevated levels of these inflammatory cytokines impaired insulin receptor action and thereby prevented downstream signaling pathways, exacerbating insulin resistance in HepG2 cells. Importantly, UC-MSCs cocultured with HepG2 could effectively alleviate PA and LPS-induced insulin resistance by blocking the NLRP3 inflammasome activation and inflammatory agents. Furthermore, knockdown of NLRP3 or IL-1β partially improved PA and

Acute pain induces insulin resistance in humans

DEFF Research Database (Denmark)

Greisen, J.; Juhl, C.B.; Grøfte, Thorbjørn

2001-01-01

Background: Painful trauma results in a disturbed metabolic state with impaired insulin sensitivity, which is related to the magnitude of the trauma. The authors explored whether pain per se influences hepatic and extrahepatic actions of insulin. Methods: Ten healthy male volunteers underwent two...... randomly sequenced hyperinsulinemic–euglycemic (insulin infusion rate, 0.6 mU · kg-1 · min-1 for 180 min) clamp studies 4 weeks apart. Self-controlled painful electrical stimulation was applied to the abdominal skin for 30 min, to a pain intensity of 8 on a visual analog scale of 0–10, just before...... the clamp procedure (study P). In the other study, no pain was inflicted (study C). Results: Pain reduced whole-body insulin-stimulated glucose uptake from 6.37 ± 1.87 mg · kg-1 · min-1 (mean ± SD) in study C to 4.97 ± 1.38 mg · kg-1 · min-1 in study P (P

A review of piscine islet xenotransplantation using wild-type tilapia donors and the production of transgenic tilapia expressing a "humanized" tilapia insulin.

Science.gov (United States)

Wright, James R; Yang, Hua; Hyrtsenko, Olga; Xu, Bao-You; Yu, Weiming; Pohajdak, Bill

2014-01-01

Most islet xenotransplantation laboratories have focused on porcine islets, which are both costly and difficult to isolate. Teleost (bony) fish, such as tilapia, possess macroscopically visible distinct islet organs called Brockmann bodies which can be inexpensively harvested. When transplanted into diabetic nude mice, tilapia islets maintain long-term normoglycemia and provide human-like glucose tolerance profiles. Like porcine islets, when transplanted into euthymic mice, they are rejected in a CD4 T-cell-dependent manner. However, unlike pigs, tilapia are so phylogenetically primitive that their cells do not express α(1,3)Gal and, because tilapia are highly evolved to live in warm stagnant waters nearly devoid of dissolved oxygen, their islet cells are exceedingly resistant to hypoxia, making them ideal for transplantation within encapsulation devices. Encapsulation, especially when combined with co-stimulatory blockade, markedly prolongs tilapia islet xenograft survival in small animal recipients, and a collaborator has shown function in diabetic cynomolgus monkeys. In anticipation of preclinical xenotransplantation studies, we have extensively characterized tilapia islets (morphology, embryologic development, cell biology, peptides, etc.) and their regulation of glucose homeostasis. Because tilapia insulin differs structurally from human insulin by 17 amino acids, we have produced transgenic tilapia whose islets stably express physiological levels of humanized insulin and have now bred these to homozygosity. These transgenic fish can serve as a platform for further development into a cell therapy product for diabetes. © 2014 The Authors. Xenotransplantation Published by John Wiley & Sons Ltd.

Combined lipidomic and proteomic analysis of isolated human islets exposed to palmitate reveals time-dependent changes in insulin secretion and lipid metabolism.

Directory of Open Access Journals (Sweden)

Kirsten Roomp

Full Text Available Studies on the pathophysiology of type 2 diabetes mellitus (T2DM have linked the accumulation of lipid metabolites to the development of beta-cell dysfunction and impaired insulin secretion. In most in vitro models of T2DM, rodent islets or beta-cell lines are used and typically focus is on specific cellular pathways or organs. Our aim was to, firstly, develop a combined lipidomics and proteomics approach for lipotoxicity in isolated human islets and, secondly, investigate if the approach could delineate novel and/ or confirm reported mechanisms of lipotoxicity. To this end isolated human pancreatic islets, exposed to chronically elevated palmitate concentrations for 0, 2 and 7 days, were functionally characterized and their levels of multiple targeted lipid and untargeted protein species determined. Glucose-stimulated insulin secretion from the islets increased on day 2 and decreased on day 7. At day 7 islet insulin content decreased and the proinsulin to insulin content ratio doubled. Amounts of cholesterol, stearic acid, C16 dihydroceramide and C24:1 sphingomyelin, obtained from the lipidomic screen, increased time-dependently in the palmitate-exposed islets. The proteomic screen identified matching changes in proteins involved in lipid biosynthesis indicating up-regulated cholesterol and lipid biosynthesis in the islets. Furthermore, proteins associated with immature secretory granules were decreased when palmitate exposure time was increased despite their high affinity for cholesterol. Proteins associated with mature secretory granules remained unchanged. Pathway analysis based on the protein and lipid expression profiles implicated autocrine effects of insulin in lipotoxicity. Taken together the study demonstrates that combining different omics approaches has potential in mapping of multiple simultaneous cellular events. However, it also shows that challenges exist for effectively combining lipidomics and proteomics in primary cells. Our

Long-term tolerability of inhaled human insulin (Exubera) in patients with poorly controlled type 2 diabetes

DEFF Research Database (Denmark)

Barnett, A H; Lange, P; Dreyer, M

2007-01-01

OBJECTIVE: Inhaled human insulin (Exubera; EXU) has shown encouraging tolerability in short-term trials. We evaluated the safety profile of EXU after long-term exposure. DESIGN: In two, open-label, 2-year studies patients poorly controlled on a sulphonylurea were randomised to adjunctive EXU...... or metformin (study 1) and patients poorly controlled on metformin were randomised to adjunctive EXU or the sulphonylurea, glibenclamide (study 2). PATIENTS: The studies included 446 (study 1) and 476 (study 2) patients with type 2 diabetes, no clinically significant respiratory disease and glycosylated....... There was no discernable effect of long-term EXU therapy on pulmonary gas exchange. Insulin antibody binding reached a plateau at 6 months and did not correlate with HbA(1c) or lung function changes. Glycaemic control was maintained over 2 years. CONCLUSIONS: Exubera was well tolerated during long-term use. Pulmonary...

Iontophoresis of monomeric insulin analogues in vitro: effects of insulin charge and skin pretreatment.

Science.gov (United States)

Langkjaer, L; Brange, J; Grodsky, G M; Guy, R H

1998-01-23

The aim of this study was to investigate the influence of association state and net charge of human insulin analogues on the rate of iontophoretic transport across hairless mouse skin, and the effect of different skin pretreatments on said transport. No insulin flux was observed with anodal delivery probably because of degradation at the Ag/AgCl anode. The flux during cathodal iontophoresis through intact skin was insignificant for human hexameric insulin, and only low and variable fluxes were observed for monomeric insulins. Using stripped skin on the other hand, the fluxes of monomeric insulins with two extra negative charges were 50-100 times higher than that of hexameric human insulin. Introducing three additional charges led to a further 2-3-fold increase in flux. Wiping the skin gently with absolute alcohol prior to iontophoresis resulted in a 1000-fold increase in transdermal transport of insulin relative to that across untreated skin, i.e. to almost the same level as stripping the skin. The alcohol pretreatment reduced the electrical resistance of the skin, presumably by lipid extraction. In conclusion, monomeric insulin analogues with at least two extra negative charges can be iontophoretically delivered across hairless mouse skin, whereas insignificant flux is observed with human, hexameric insulin. Wiping the skin with absolute alcohol prior to iontophoresis gave substantially improved transdermal transport of monomeric insulins resulting in clinically relevant delivery rates for basal treatment.

Generation of Insulin-Producing Cells from Human Bone Marrow-Derived Mesenchymal Stem Cells: Comparison of Three Differentiation Protocols

Directory of Open Access Journals (Sweden)

Mahmoud M. Gabr

2014-01-01

Full Text Available Introduction. Many protocols were utilized for directed differentiation of mesenchymal stem cells (MSCs to form insulin-producing cells (IPCs. We compared the relative efficiency of three differentiation protocols. Methods. Human bone marrow-derived MSCs (HBM-MSCs were obtained from three insulin-dependent type 2 diabetic patients. Differentiation into IPCs was carried out by three protocols: conophylline-based (one-step protocol, trichostatin-A-based (two-step protocol, and β-mercaptoethanol-based (three-step protocol. At the end of differentiation, cells were evaluated by immunolabeling for insulin production, expression of pancreatic endocrine genes, and release of insulin and c-peptide in response to increasing glucose concentrations. Results. By immunolabeling, the proportion of generated IPCs was modest (≃3% in all the three protocols. All relevant pancreatic endocrine genes, insulin, glucagon, and somatostatin, were expressed. There was a stepwise increase in insulin and c-peptide release in response to glucose challenge, but the released amounts were low when compared with those of pancreatic islets. Conclusion. The yield of functional IPCs following directed differentiation of HBM-MSCs was modest and was comparable among the three tested protocols. Protocols for directed differentiation of MSCs need further optimization in order to be clinically meaningful. To this end, addition of an extracellular matrix and/or a suitable template should be attempted.

Liraglutide, a once-daily human GLP-1 analogue, improves pancreatic B-cell function and arginine-stimulated insulin secretion during hyperglycaemia in patients with Type 2 diabetes mellitus

DEFF Research Database (Denmark)

Vilsbøll, Tina; Brock, Birgitte; Perrild, Hans

2008-01-01

To assess the effect of liraglutide, a once-daily human glucagon-like peptide-1 analogue on pancreatic B-cell function. methods: Patients with Type 2 diabetes (n = 39) were randomized to treatment with 0.65, 1.25 or 1.9 mg/day liraglutide or placebo for 14 weeks. First- and second-phase insulin...... release were measured by means of the insulin-modified frequently sampled intravenous glucose tolerance test. Arginine-stimulated insulin secretion was measured during a hyperglycaemic clamp (20 mmol/l). Glucose effectiveness and insulin sensitivity were estimated by means of the insulin...

Studies of relationships between variation of the human G protein-coupled receptor 40 Gene and Type 2 diabetes and insulin release

DEFF Research Database (Denmark)

Hamid, Y H; Vissing, H; Holst, B

2005-01-01

AIMS: Recently, a novel human G protein-coupled receptor 40 (GPR40), which is predominantly expressed in pancreatic islets, was shown to mediate an amplifying effect of long-chain fatty acids on glucose-induced insulin secretion. The present aim was to examine the coding region of GPR40 for varia......AIMS: Recently, a novel human G protein-coupled receptor 40 (GPR40), which is predominantly expressed in pancreatic islets, was shown to mediate an amplifying effect of long-chain fatty acids on glucose-induced insulin secretion. The present aim was to examine the coding region of GPR40...... compared with the wild type (P = 0.01). The Arg211His polymorphism had a similar allele frequency among 1384 Type 2 diabetic patients [MAF%; 23.4 (95% CI: 21.8-25.0)] and 4424 middle-aged glucose-tolerant subjects [24.1% (23.2-25.0)]. A genotype-quantitative trait study of 5597 non-diabetic, middle...

Excessive Cellular Proliferation Negatively Impacts Reprogramming Efficiency of Human Fibroblasts.

Science.gov (United States)

Gupta, Manoj K; Teo, Adrian Kee Keong; Rao, Tata Nageswara; Bhatt, Shweta; Kleinridders, Andre; Shirakawa, Jun; Takatani, Tomozumi; Hu, Jiang; De Jesus, Dario F; Windmueller, Rebecca; Wagers, Amy J; Kulkarni, Rohit N

2015-10-01

The impact of somatic cell proliferation rate on induction of pluripotent stem cells remains controversial. Herein, we report that rapid proliferation of human somatic fibroblasts is detrimental to reprogramming efficiency when reprogrammed using a lentiviral vector expressing OCT4, SOX2, KLF4, and cMYC in insulin-rich defined medium. Human fibroblasts grown in this medium showed higher proliferation, enhanced expression of insulin signaling and cell cycle genes, and a switch from glycolytic to oxidative phosphorylation metabolism, but they displayed poor reprogramming efficiency compared with cells grown in normal medium. Thus, in contrast to previous studies, our work reveals an inverse correlation between the proliferation rate of somatic cells and reprogramming efficiency, and also suggests that upregulation of proteins in the growth factor signaling pathway limits the ability to induce pluripotency in human somatic fibroblasts. The efficiency with which human cells can be reprogrammed is of interest to stem cell biology. In this study, human fibroblasts cultured in media containing different concentrations of growth factors such as insulin and insulin-like growth factor-1 exhibited variable abilities to proliferate, with consequences on pluripotency. This occurred in part because of changes in the expression of proteins involved in the growth factor signaling pathway, glycolysis, and oxidative phosphorylation. These findings have implications for efficient reprogramming of human cells. ©AlphaMed Press.

Insulin Promotes the Proliferation of Human Umbilical Cord Matrix-Derived Mesenchymal Stem Cells by Activating the Akt-Cyclin D1 Axis

Directory of Open Access Journals (Sweden)

Peng Li

2017-01-01

Full Text Available Background. The functions of insulin in mesenchymal stem cells (MSC remain poorly understood. Methods. MSC from human umbilical cord matrix (UCM cultured in serum-free media (SFM with or without insulin were subjected to various molecular biological analyses to determine their proliferation and growth states, expression levels of Akt-cyclin D1 signaling molecules, and in vitro differentiation capacities. Results. Insulin accelerated the G1-S cell cycle progression of UCM-MSC and significantly stimulated their proliferation and growth in SFM. The pro-proliferative action of insulin was associated with augmented cyclin D1 and phosphorylated Akt expression levels. Akt inactivation remarkably abrogated insulin-induced increases in cyclin D1 expression and cell proliferation, indicating that insulin enhances the proliferation of UCM-MSC via acceleration of the G1-S transition mediated by the Akt-cyclin D1 pathway. Additionally, the UCM-MSC propagated in SFM supplemented with insulin exhibited similar specific surface antigen profiles and differentiation capacities as those generated in conventional media containing fetal bovine serum. Conclusions. These findings suggest that insulin acts solely to promote UCM-MSC proliferation without affecting their immunophenotype and differentiation potentials and thus have important implications for utilizing insulin to expand clinical-grade MSC in vitro.

Inhibition of human MCF-7 breast cancer cells and HT-29 colon cancer cells by rice-produced recombinant human insulin-like growth binding protein-3 (rhIGFBP-3.

Directory of Open Access Journals (Sweden)

Stanley C K Cheung

Full Text Available BACKGROUND: Insulin-like growth factor binding protein-3 (IGFBP-3 is a multifunctional molecule which is closely related to cell growth, apoptosis, angiogenesis, metabolism and senescence. It combines with insulin-like growth factor-I (IGF-I to form a complex (IGF-I/IGFBP-3 that can treat growth hormone insensitivity syndrome (GHIS and reduce insulin requirement in patients with diabetes. IGFBP-3 alone has been shown to have anti-proliferation effect on numerous cancer cells. METHODOLOGY/PRINCIPAL FINDINGS: We reported here an expression method to produce functional recombinant human IGFBP-3 (rhIGFBP-3 in transgenic rice grains. Protein sorting sequences, signal peptide and endoplasmic reticulum retention tetrapeptide (KDEL were included in constructs for enhancing rhIGFBP-3 expression. Western blot analysis showed that only the constructs with signal peptide were successfully expressed in transgenic rice grains. Both rhIGFBP-3 proteins, with or without KDEL sorting sequence inhibited the growth of MCF-7 human breast cancer cells (65.76 ± 1.72% vs 45.00 ± 0.86%, p < 0.05; 50.84 ± 1.97% vs 45.00 ± 0.86%, p < 0.01 respectively and HT-29 colon cancer cells (65.14 ± 3.84% vs 18.01 ± 13.81%, p < 0.05 and 54.7 ± 9.44% vs 18.01 ± 13.81%, p < 0.05 respectively when compared with wild type rice. CONCLUSION/SIGNIFICANCE: These findings demonstrated the feasibility of producing biological active rhIGFBP-3 in rice using a transgenic approach, which will definitely encourage more research on the therapeutic use of hIGFBP-3 in future.

Acute exercise and physiological insulin induce distinct phosphorylation signatures on TBC1D1 and TBC1D4 proteins in human skeletal muscle.

Science.gov (United States)

Treebak, Jonas T; Pehmøller, Christian; Kristensen, Jonas M; Kjøbsted, Rasmus; Birk, Jesper B; Schjerling, Peter; Richter, Erik A; Goodyear, Laurie J; Wojtaszewski, Jørgen F P

2014-01-15

We investigated the phosphorylation signatures of two Rab-GTPase activating proteins TBC1D1 and TBC1D4 in human skeletal muscle in response to physical exercise and physiological insulin levels induced by a carbohydrate rich meal using a paired experimental design. Eight healthy male volunteers exercised in the fasted or fed state and muscle biopsies were taken before and immediately after exercise. We identified TBC1D1/4 phospho-sites that (1) did not respond to exercise or postprandial increase in insulin (TBC1D4: S666), (2) responded to insulin only (TBC1D4: S318), (3) responded to exercise only (TBC1D1: S237, S660, S700; TBC1D4: S588, S751), and (4) responded to both insulin and exercise (TBC1D1: T596; TBC1D4: S341, T642, S704). In the insulin-stimulated leg, Akt phosphorylation of both T308 and S473 correlated significantly with multiple sites on both TBC1D1 (T596) and TBC1D4 (S318, S341, S704). Interestingly, in the exercised leg in the fasted state TBC1D1 phosphorylation (S237, T596) correlated significantly with the activity of the α2/β2/γ3 AMPK trimer, whereas TBC1D4 phosphorylation (S341, S704) correlated with the activity of the α2/β2/γ1 AMPK trimer. Our data show differential phosphorylation of TBC1D1 and TBC1D4 in response to physiological stimuli in human skeletal muscle and support the idea that Akt and AMPK are upstream kinases. TBC1D1 phosphorylation signatures were comparable between in vitro contracted mouse skeletal muscle and exercised human muscle, and we show that AMPK regulated phosphorylation of these sites in mouse muscle. Contraction and exercise elicited a different phosphorylation pattern of TBC1D4 in mouse compared with human muscle, and although different circumstances in our experimental setup may contribute to this difference, the observation exemplifies that transferring findings between species is problematic.

Insulin stimulates translocation of human GLUT4 to the membrane in fat bodies of transgenic Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Georgeta Crivat

Full Text Available The fruit fly Drosophila melanogaster is an excellent model system for studies of genes controlling development and disease. However, its applicability to physiological systems is less clear because of metabolic differences between insects and mammals. Insulin signaling has been studied in mammals because of relevance to diabetes and other diseases but there are many parallels between mammalian and insect pathways. For example, deletion of Drosophila Insulin-Like Peptides resulted in 'diabetic' flies with elevated circulating sugar levels. Whether this situation reflects failure of sugar uptake into peripheral tissues as seen in mammals is unclear and depends upon whether flies harbor the machinery to mount mammalian-like insulin-dependent sugar uptake responses. Here we asked whether Drosophila fat cells are competent to respond to insulin with mammalian-like regulated trafficking of sugar transporters. Transgenic Drosophila expressing human glucose transporter-4 (GLUT4, the sugar transporter expressed primarily in insulin-responsive tissues, were generated. After expression in fat bodies, GLUT4 intracellular trafficking and localization were monitored by confocal and total internal reflection fluorescence microscopy (TIRFM. We found that fat body cells responded to insulin with increased GLUT4 trafficking and translocation to the plasma membrane. While the amplitude of these responses was relatively weak in animals reared on a standard diet, it was greatly enhanced in animals reared on sugar-restricted diets, suggesting that flies fed standard diets are insulin resistant. Our findings demonstrate that flies are competent to mobilize translocation of sugar transporters to the cell surface in response to insulin. They suggest that Drosophila fat cells are primed for a response to insulin and that these pathways are down-regulated when animals are exposed to constant, high levels of sugar. Finally, these studies are the first to use TIRFM to

Insulin Stimulates Translocation of Human GLUT4 to the Membrane in Fat Bodies of Transgenic Drosophila melanogaster

Science.gov (United States)

Crivat, Georgeta; Lizunov, Vladimir A.; Li, Caroline R.; Stenkula, Karin G.; Zimmerberg, Joshua; Cushman, Samuel W.; Pick, Leslie

2013-01-01

The fruit fly Drosophila melanogaster is an excellent model system for studies of genes controlling development and disease. However, its applicability to physiological systems is less clear because of metabolic differences between insects and mammals. Insulin signaling has been studied in mammals because of relevance to diabetes and other diseases but there are many parallels between mammalian and insect pathways. For example, deletion of Drosophila Insulin-Like Peptides resulted in ‘diabetic’ flies with elevated circulating sugar levels. Whether this situation reflects failure of sugar uptake into peripheral tissues as seen in mammals is unclear and depends upon whether flies harbor the machinery to mount mammalian-like insulin-dependent sugar uptake responses. Here we asked whether Drosophila fat cells are competent to respond to insulin with mammalian-like regulated trafficking of sugar transporters. Transgenic Drosophila expressing human glucose transporter-4 (GLUT4), the sugar transporter expressed primarily in insulin-responsive tissues, were generated. After expression in fat bodies, GLUT4 intracellular trafficking and localization were monitored by confocal and total internal reflection fluorescence microscopy (TIRFM). We found that fat body cells responded to insulin with increased GLUT4 trafficking and translocation to the plasma membrane. While the amplitude of these responses was relatively weak in animals reared on a standard diet, it was greatly enhanced in animals reared on sugar-restricted diets, suggesting that flies fed standard diets are insulin resistant. Our findings demonstrate that flies are competent to mobilize translocation of sugar transporters to the cell surface in response to insulin. They suggest that Drosophila fat cells are primed for a response to insulin and that these pathways are down-regulated when animals are exposed to constant, high levels of sugar. Finally, these studies are the first to use TIRFM to monitor insulin

MicroRNA-223 Expression Is Upregulated in Insulin Resistant Human Adipose Tissue

Directory of Open Access Journals (Sweden)

Tung-Yueh Chuang

2015-01-01

Full Text Available MicroRNAs (miRNAs are short noncoding RNAs involved in posttranscriptional regulation of gene expression and influence many cellular functions including glucose and lipid metabolism. We previously reported that adipose tissue (AT from women with polycystic ovary syndrome (PCOS or controls with insulin resistance (IR revealed a differentially expressed microRNA (miRNA profile, including upregulated miR-93 in PCOS patients and in non-PCOS women with IR. Overexpressed miR-93 directly inhibited glucose transporter isoform 4 (GLUT4 expression, thereby influencing glucose metabolism. We have now studied the role of miR-223, which is also abnormally expressed in the AT of IR subjects. Our data indicates that miR-223 is significantly overexpressed in the AT of IR women, regardless of whether they had PCOS or not. miR-223 expression in AT was positively correlated with HOMA-IR. Unlike what is reported in cardiomyocytes, overexpression of miR-223 in human differentiated adipocytes was associated with a reduction in GLUT4 protein content and insulin-stimulated glucose uptake. In addition, our data suggests miR-223 regulates GLUT4 expression by direct binding to its 3′ untranslated region (3′UTR. In conclusion, in AT miR-223 is an IR-related miRNA that may serve as a potential therapeutic target for the treatment of IR-related disorders.

Lipodystrophy in human immunodeficiency virus patients impairs insulin action and induces defects in beta-cell function

DEFF Research Database (Denmark)

Andersen, Ove; Haugaard, Steen B; Andersen, Ulrik B

2003-01-01

The pathophysiology of insulin resistance in human immunodeficiency virus (HIV)-associated lipodystrophy syndrome (HALS) is not fully clarified. We investigated 18 men with HALS and 18 HIV-positive males without lipodystrophy (control subjects). Duration and modality of antiretroviral therapy were...... that the percentage of limb fat (ie, peripheral-fat-mass/[peripheral-fat-mass + trunk-fat-mass]. 100%) was reduced in HALS patients (36% v 46%, P =.0002). Multiple linear regression analysis indicated that percentage of limb fat explained 53% of the variability of GDR and 45% of the variability of NOGM in HALS...

Human circulating monocytes internalize 125I-insulin in a similar fashion to rat hepatocytes: relevance to receptor regulation in target and nontarget tissues

International Nuclear Information System (INIS)

Grunberger, G.; Robert, A.; Carpentier, J.L.; Dayer, J.M.; Roth, A.; Stevenson, H.C.; Orci, L.; Gorden, P.

1985-01-01

Circulating monocytes bind 125 I-insulin in a specific fashion and have been used to analyze the ambient receptor status in humans. When freshly isolated circulating monocytes are incubated with 125 I-insulin and examined by electron microscopic autoradiography, approximately 18% of the labeled material is internalized after 15 minutes at 37 degrees C. By 2 hours at 37 degrees C, approximately one half of the 125 I-insulin is internalized. Internalization occurs also at 15 degrees C but at a slower rate. Furthermore, the monocytes bind and internalize 125 I-insulin in a manner that mirrors that of major target tissues, such as rat hepatocytes. These data suggest that the insulin receptor of the circulating monocyte might be regulated by adsorptive endocytosis in a manner analogous to that of target tissue, such as the liver

Differential effects of prednisone and growth hormone on fuel metabolism and insulin antagonism in humans

International Nuclear Information System (INIS)

Horber, F.F.; Marsh, H.M.; Haymond, M.W.

1991-01-01

Human growth hormone (hGH) and prednisone cause insulin resistance and glucose intolerance. However, it is unknown whether hGH and prednisone antagonize insulin action on protein, fat, and carbohydrate metabolism by a common or independent mechanism. Therefore, protein, fat, and carbohydrate metabolism was assessed simultaneously in four groups of eight subjects each after 7 days of placebo, recombinant DNA hGH (rhGH; 0.1 mg.kg-1.day-1), prednisone (0.8 mg.kg-1.day-1), or rhGH and prednisone administration after an 18-h fast and during gut infusion of glucose and amino acids (fed state). Fasting plasma glucose concentrations were similar during placebo and rhGH but elevated (P less than 0.001) during combined treatment, whereas plasma insulin concentrations were higher (237 +/- 57 pmol/ml, P less than 0.001) during combined than during placebo, rhGH, or prednisone treatment (34, 52, and 91 pM, respectively). In the fed state, plasma glucose concentrations were elevated only during combined treatment (11.3 +/- 2.1 mM, P less than 0.001). Plasma insulin concentrations were elevated during therapy with prednisone alone and rhGH alone (667 +/- 72 and 564 +/- 65 pmol/ml, respectively, P less than 0.001) compared with placebo (226 +/- 44 pmol/ml) but lower than with the combined rhGH and prednisone treatment (1249 +/- 54 pmol/ml, P less than 0.01). Protein oxidation 14 C leucine increased (P less than 0.001) with prednisone therapy, decreased (P less than 0.001) with rhGH treatment, and was normal during the combined treatment

Medical implications of obesity in horses--lessons for human obesity.

Science.gov (United States)

Johnson, Philip J; Wiedmeyer, Charles E; Messer, Nat T; Ganjam, Venkataseshu K

2009-01-01

There is growing recognition that obesity is common and represents a significant detriment to the health of companion animals in a manner similar to that by which it is affecting the human population. As is the case for other species, obesity appears to promote insulin resistance in horses and it is through this pathophysiological process that many of the adverse medical consequences of obesity are being characterized. Equine medical conditions that have been described in the context of obesity and insulin resistance differ from those in humans. Chronic human conditions that have been attributed to obesity and insulin resistance, such as atherosclerosis and diabetes mellitus, are rarely described in obese horses. Significant current interest is centered on the recognition that insulin resistance plays a role in the pathogenesis of laminitis, a potentially severe and debilitating cause of lameness in the equine species. Other equine medical conditions that are more likely in obese, insulin-resistant individuals include hyperlipemia (hepatic lipidosis) and developmental orthopedic disease (osteochondrosis). Pituitary pars intermedia dysfunction (equine Cushing's syndrome) represents another common endocrinopathic condition of older horses associated with insulin resistance. This review presents an introductory overview of the present understanding of obesity and insulin resistance and how these conditions may be associated with disease conditions in horses. © Diabetes Technology Society

Medical Implications of Obesity in Horses—Lessons for Human Obesity

Science.gov (United States)

Johnson, Philip J.; Wiedmeyer, Charles E.; Messer, Nat T.; Ganjam, Venkataseshu K.

2009-01-01

There is growing recognition that obesity is common and represents a significant detriment to the health of companion animals in a manner similar to that by which it is affecting the human population. As is the case for other species, obesity appears to promote insulin resistance in horses and it is through this pathophysiological process that many of the adverse medical consequences of obesity are being characterized. Equine medical conditions that have been described in the context of obesity and insulin resistance differ from those in humans. Chronic human conditions that have been attributed to obesity and insulin resistance, such as atherosclerosis and diabetes mellitus, are rarely described in obese horses. Significant current interest is centered on the recognition that insulin resistance plays a role in the pathogenesis of laminitis, a potentially severe and debilitating cause of lameness in the equine species. Other equine medical conditions that are more likely in obese, insulin-resistant individuals include hyperlipemia (hepatic lipidosis) and developmental orthopedic disease (osteochondrosis). Pituitary pars intermedia dysfunction (equine Cushing's syndrome) represents another common endocrinopathic condition of older horses associated with insulin resistance. This review presents an introductory overview of the present understanding of obesity and insulin resistance and how these conditions may be associated with disease conditions in horses. PMID:20046661

Isolation of an insulin-like growth factor II cDNA with a unique 5' untranslated region from human placenta

International Nuclear Information System (INIS)

Shen, Shujane; Daimon, Makoto; Wang, Chunyeh; Ilan, J.; Jansen, M.

1988-01-01

Human insulin-like growth factor II (IGF-II) cDNA from a placental library was isolated and sequenced. The 5' untranslated region (5'-UTR) sequence of this cDNA differs completely from that of adult human liver and has considerable base sequence identity to the same region of an IGF-II cDNA of a rat liver cell line, BRL-3A. Human placental poly(A) + RNA was probed with either the 5'-UTR of the isolated human placental IGF-II cDNA or the 5'-UTR of the IGF-II cDNA obtained from adult human liver. No transcripts were detected by using the 5'-UTR of the adult liver IGF-II as the probe. In contrast, three transcripts of 6.0, 3.2, and 2.2 kilobases were detected by using the 5'-UTR of the placental IGF-II cDNA as the probe or the probe from the coding sequence. A fourth IGF-II transcript of 4.9 kilobases presumably containing a 5'-UTR consisting of a base sequence dissimilar to that of either IGF-II 5'-UTR was apparent. Therefore, IGF-II transcripts detected may be products of alternative splicing as their 5'-UTR sequence is contained within the human IGF-II gene or they may be a consequence of alternative promoter utilization in placenta

Palmitate-induced inflammatory pathways in human adipose microvascular endothelial cells promote monocyte adhesion and impair insulin transcytosis.

Science.gov (United States)

Pillon, Nicolas J; Azizi, Paymon M; Li, Yujin E; Liu, Jun; Wang, Changsen; Chan, Kenny L; Hopperton, Kathryn E; Bazinet, Richard P; Heit, Bryan; Bilan, Philip J; Lee, Warren L; Klip, Amira

2015-07-01

Obesity is associated with inflammation and immune cell recruitment to adipose tissue, muscle and intima of atherosclerotic blood vessels. Obesity and hyperlipidemia are also associated with tissue insulin resistance and can compromise insulin delivery to muscle. The muscle/fat microvascular endothelium mediates insulin delivery and facilitates monocyte transmigration, yet its contribution to the consequences of hyperlipidemia is poorly understood. Using primary endothelial cells from human adipose tissue microvasculature (HAMEC), we investigated the effects of physiological levels of fatty acids on endothelial inflammation and function. Expression of cytokines and adhesion molecules was measured by RT-qPCR. Signaling pathways were evaluated by pharmacological manipulation and immunoblotting. Surface expression of adhesion molecules was determined by immunohistochemistry. THP1 monocyte interaction with HAMEC was measured by cell adhesion and migration across transwells. Insulin transcytosis was measured by total internal reflection fluorescence microscopy. Palmitate, but not palmitoleate, elevated the expression of IL-6, IL-8, TLR2 (Toll-like receptor 2), and intercellular adhesion molecule 1 (ICAM-1). HAMEC had markedly low fatty acid uptake and oxidation, and CD36 inhibition did not reverse the palmitate-induced expression of adhesion molecules, suggesting that inflammation did not arise from palmitate uptake/metabolism. Instead, inhibition of TLR4 to NF-κB signaling blunted palmitate-induced ICAM-1 expression. Importantly, palmitate-induced surface expression of ICAM-1 promoted monocyte binding and transmigration. Conversely, palmitate reduced insulin transcytosis, an effect reversed by TLR4 inhibition. In summary, palmitate activates inflammatory pathways in primary microvascular endothelial cells, impairing insulin transport and increasing monocyte transmigration. This behavior may contribute in vivo to reduced tissue insulin action and enhanced tissue

From Human Mesenchymal Stem Cells to Insulin-Producing Cells: Comparison between Bone Marrow- and Adipose Tissue-Derived Cells.

Science.gov (United States)

Gabr, Mahmoud M; Zakaria, Mahmoud M; Refaie, Ayman F; Abdel-Rahman, Engy A; Reda, Asmaa M; Ali, Sameh S; Khater, Sherry M; Ashamallah, Sylvia A; Ismail, Amani M; Ismail, Hossam El-Din A; El-Badri, Nagwa; Ghoneim, Mohamed A

2017-01-01

The aim of this study is to compare human bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs), for their differentiation potentials to form insulin-producing cells. BM-MSCs were obtained during elective orthotopic surgery and AT-MSCs from fatty aspirates during elective cosmetics procedures. Following their expansion, cells were characterized by phenotyping, trilineage differentiation ability, and basal gene expression of pluripotency genes and for their metabolic characteristics. Cells were differentiated according to a Trichostatin-A based protocol. The differentiated cells were evaluated by immunocytochemistry staining for insulin and c-peptide. In addition the expression of relevant pancreatic endocrine genes was determined. The release of insulin and c-peptide in response to a glucose challenge was also quantitated. There were some differences in basal gene expression and metabolic characteristics. After differentiation the proportion of the resulting insulin-producing cells (IPCs), was comparable among both cell sources. Again, there were no differences neither in the levels of gene expression nor in the amounts of insulin and c-peptide release as a function of glucose challenge. The properties, availability, and abundance of AT-MSCs render them well-suited for applications in regenerative medicine. Conclusion . BM-MSCs and AT-MSCs are comparable regarding their differential potential to form IPCs. The availability and properties of AT-MSCs render them well-suited for applications in regenerative medicine.

Baculovirus-mediated gene transfer and recombinant protein expression do not interfere with insulin dependent phosphorylation of PKB/Akt in human SHSY-5Y and C3A cells

Directory of Open Access Journals (Sweden)

Selander Martin

2007-02-01

Full Text Available Abstract Background Recombinant adenovirus vectors and transfection agents comprising cationic lipids are widely used as gene delivery vehicles for functional expression in cultured cells. Consequently, these tools are utilized to investigate the effects of functional over-expression of proteins on insulin mediated events. However, we have previously reported that cationic lipid reagents cause a state of insulin unresponsiveness in cell cultures. In addition, we have found that cultured cells often do not respond to insulin stimulation following adenovirus treatment. Infection with adenovirus compromises vital functions of the host cell leading to the activation of protein kinases central to insulin signalling, such as protein kinase B/Akt. Therefore, we investigated the effect of adenovirus infection on insulin unresponsiveness by means of Akt activation in cultured cells. Moreover, we investigated the use of baculovirus as a heterologous viral gene delivery vehicle to circumvent these phenomena. Since the finding that baculovirus can efficiently transduce mammalian cells, the applications of this viral system in gene delivery has greatly expanded and one advantage is the virtual absence of cytotoxicity in mammalian cells. Results We show that infection of human neuroblastoma SHSY-5Y and liver C3A cells with recombinant adenovirus results in the activation of Akt in a dose dependent manner. In addition, this activation makes treated cells unresponsive to insulin stimulation as determined by an apparent lack of differential phosphorylation of Akt on serine-473. Our data further indicate that the use of recombinant baculovirus does not increase the phosphorylation of Akt in SHSY-5Y and C3A cells. Moreover, following infection with baculovirus, SHSY-5Y and C3A cells respond to insulin by means of phosphorylation of Akt on serine-473 in the same manner as uninfected cells. Conclusion Widely-used adenovirus vectors for gene delivery cause a state of

Insulin Plays a Permissive Role for the Vasoactive Effect of GIP Regulating Adipose Tissue Metabolism in Humans

DEFF Research Database (Denmark)

Asmar, Meena; Simonsen, Lene; Asmar, Ali

2016-01-01

CONTEXT AND OBJECTIVE: Glucose-dependent insulinotropic polypeptide (GIP) in combination with hyperinsulinemia increases blood flow and triglyceride (TAG) clearance in subcutaneous (sc) abdominal adipose tissue in lean humans. The present experiments were performed to further investigate the role...... of insulin for the vasoactive effect of GIP in adipose tissue metabolism and whether the vasodilatory effect of GIP is dependent on C-peptide. METHODS: Six lean healthy subjects were studied. The sc abdominal adipose tissue metabolism was assessed by Fick's principle during GIP infusion (1.5 pmol...

High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression

DEFF Research Database (Denmark)

Fred, Rikard G; Bang-Berthelsen, Claus H; Mandrup-Poulsen, Thomas

2010-01-01

BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB) is required for stabilization of insulin mRNA and the PTB mRNA 3......'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY...... for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB...

Derivation of Insulin Producing Cells From Human Endometrial Stromal Stem Cells and Use in the Treatment of Murine Diabetes

OpenAIRE

Santamaria, Xavier; Massasa, Efi E; Feng, Yuzhe; Wolff, Erin; Taylor, Hugh S

2011-01-01

Pancreatic islet cell transplantation is an effective approach to treat type 1 diabetes, however the shortage of cadaveric donors and limitations due to rejection require alternative solutions. Multipotent cells derived from the uterine endometrium have the ability to differentiate into mesodermal and ectodermal cellular lineages, suggesting the existence of mesenchymal stem cells in this tissue. We differentiated human endometrial stromal stem cells (ESSC) into insulin secreting cells using ...

Potency of full-length MGF to induce maximal activation of the IGF-I R Is similar to recombinant human IGF-I at high equimolar concentrations

NARCIS (Netherlands)

J.A.M.J.L. Janssen (Joseph); L.J. Hofland (Leo); C.J. Strasburger; E.S.R.D. Van Dungen (Elisabeth S.R. Den); M. Thevis (Mario)

2016-01-01

textabstractAims To compare full-length mechano growth factor (full-length MGF) with human recombinant insulin-like growth factor-I (IGF-I) and human recombinant insulin (HI) in their ability to activate the human IGF-I receptor (IGF-IR), the human insulin receptor (IR-A) and the human insulin

Human beta-cell precursors mature into functional insulin-producing cells in an immunoisolation device: implications for diabetes cell therapies.

Science.gov (United States)

Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y; Geron, Ifat; Strongin, Alex Y; Itkin-Ansari, Pamela

2009-04-15

Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human beta-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human beta-cells and their progenitors and (2) the engraftment of encapsulated murine beta-cells in allo- and autoimmune settings. Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells ameliorated diabetes without stimulating a detectable T-cell response. We demonstrate for the first time that human beta-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of beta-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells.

Human β-cell Precursors Mature Into Functional Insulin-producing Cells in an Immunoisolation Device: Implications for Diabetes Cell Therapies

Science.gov (United States)

Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y.; Geron, Ifat; Strongin, Alex Y.; Itkin-Ansari, Pamela

2009-01-01

Background Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human β-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human β-cells and their progenitors and (2) the engraftment of encapsulated murine β-cells in allo- and autoimmune settings. Methods Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Results Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary β-cells ameliorated diabetes without stimulating a detectable T-cell response. Conclusions We demonstrate for the first time that human β-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of β-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells. PMID:19352116

Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

Science.gov (United States)

Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

2016-06-01

Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

Cell motility in models of wounded human skin is improved by Gap27 despite raised glucose, insulin and IGFBP-5

Energy Technology Data Exchange (ETDEWEB)

Wright, Catherine S.; Berends, Rebecca F. [Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow G4 0BA (United Kingdom); Flint, David J. [Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE (United Kingdom); Martin, Patricia E.M., E-mail: Patricia.Martin@gcu.ac.uk [Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow G4 0BA (United Kingdom)

2013-02-15

Reducing Cx43 expression stimulates skin wound healing. This is mimicked in models when Cx43 function is blocked by the connexin mimetic peptide Gap27. IGF-I also stimulates wound healing with IGFBP-5 attenuating its actions. Further, the IGF-I to IGFBP-5 ratio is altered in diabetic skin, where wound closure is impaired. We investigated whether Gap27 remains effective in augmenting scrape-wound closure in human skin wound models simulating diabetes-induced changes, using culture conditions with raised glucose, insulin and IGFBP-5. Gap27 increased scrape-wound closure in normal glucose and insulin (NGI) and to a lesser extent in high glucose and insulin (HGI). IGF-I enhanced scrape-wound closure in keratinocytes whereas IGFBP-5 inhibited this response. Gap27 overcame the inhibitory effects of IGFBP-5 on IGF-I activity. Connexin-mediated communication (CMC) was reduced in HGI, despite raised Cx43, and Gap27 significantly decreased CMC in NGI and HGI. IGF-I and IGFBP-5 did not affect CMC. IGF-I increased keratinocyte proliferation in NGI, and Gap27 increased proliferation in NGI to a greater extent than in HGI. We conclude that IGF-I and Gap27 stimulate scrape-wound closure by independent mechanisms with Gap27 inhibiting Cx43 function. Gap27 can enhance wound closure in diabetic conditions, irrespective of the IGF-I:IGFBP-5 balance. - Highlights: ► Human organotypic and keratinocyte ‘diabetic’ skin models were used to demonstrate the ability of Gap27 to improve scrape-wound closure. ► Gap27 enhanced scrape-wound closure by reducing Cx43-mediated communication, whereas IGFBP-5 retarded cell migration. ► IGF-I and IGFBP-5 did not affect connexin-mediated pathways. ► Gap27 can override altered glucose, insulin, IGF-I, and IGFBP-5 in ‘diabetic’ skin models and thus has therapeutic potential.

Insulin and GH signaling in human skeletal muscle in vivo following exogenous GH exposure: impact of an oral glucose load.

Directory of Open Access Journals (Sweden)

Thomas Krusenstjerna-Hafstrøm

2011-05-01

Full Text Available GH induces acute insulin resistance in skeletal muscle in vivo, which in rodent models has been attributed to crosstalk between GH and insulin signaling pathways. Our objective was to characterize time course changes in signaling pathways for GH and insulin in human skeletal muscle in vivo following GH exposure in the presence and absence of an oral glucose load.Eight young men were studied in a single-blinded randomized crossover design on 3 occasions: 1 after an intravenous GH bolus 2 after an intravenous GH bolus plus an oral glucose load (OGTT, and 3 after intravenous saline plus OGTT. Muscle biopsies were taken at t = 0, 30, 60, and 120. Blood was sampled at frequent intervals for assessment of GH, insulin, glucose, and free fatty acids (FFA.GH increased AUC(glucose after an OGTT (p<0.05 without significant changes in serum insulin levels. GH induced phosphorylation of STAT5 independently of the OGTT. Conversely, the OGTT induced acute phosphorylation of the insulin signaling proteins Akt (ser(473 and thr(308, and AS160.The combination of OGTT and GH suppressed Akt activation, whereas the downstream expression of AS160 was amplified by GH. WE CONCLUDED THE FOLLOWING: 1 A physiological GH bolus activates STAT5 signaling pathways in skeletal muscle irrespective of ambient glucose and insulin levels 2 Insulin resistance induced by GH occurs without a distinct suppression of insulin signaling proteins 3 The accentuation of the glucose-stimulated activation of AS 160 by GH does however indicate a potential crosstalk between insulin and GH.ClinicalTrials.gov NCT00477997.

Biopharmaceutical characterisation of insulin and recombinant human growth hormone loaded lipid submicron particles produced by supercritical gas micro-atomisation.

Science.gov (United States)

Salmaso, Stefano; Bersani, Sara; Elvassore, Nicola; Bertucco, Alberto; Caliceti, Paolo

2009-09-08

Homogeneous dispersions of insulin and recombinant human growth hormone (rh-GH) in tristearin/phosphatidylcholine/PEG mixtures (1.3:1.3:0.25:0.15 w/w ratio) were processed by supercritical carbon dioxide gas micro-atomisation to produce protein-loaded lipid particles. The process yielded spherical particles, with a 197+/-94 nm mean diameter, and the insulin and rh-GH recovery in the final product was 57+/-8% and 48+/-5%, respectively. In vitro, the proteins were slowly released for about 70-80 h according to a diffusive mechanism. In vivo, the insulin and glucose profiles in plasma obtained by subcutaneous administration of a dose of particles containing 2 microg insulin to diabetic mice overlapped that obtained with 2 microg of insulin in solution. Administration of a dose of particles containing 5 microg insulin resulted in faster and longer glycaemia reduction. Oral administration of 20 and 50 microg insulin equivalent particles produced a significant hypoglycaemic effect. The glucose levels decreased since 2h after administration, reaching about 50% and 70% glucose reduction in 1-2h with the lower and higher dose, respectively. As compared to subcutaneous administration, the relative pharmacological bioavailability obtained with 20 and 50 microg equivalent insulin particles was 7.7% and 6.7%, respectively. Daily subcutaneous administration of 40 microg of rh-GH-loaded particles to hypophysectomised rats induced similar body weight increase as 40 microg rh-GH in solution. The daily oral administration of 400 microg rh-GH equivalent particles elicited a slight body weight increase, which corresponded to a relative pharmacological bioavailability of 3.4% compared to subcutaneous administration.

Sodium phenylbutyrate, a drug with known capacity to reduce endoplasmic reticulum stress, partially alleviates lipid-induced insulin resistance and beta-cell dysfunction in humans.

Science.gov (United States)

Xiao, Changting; Giacca, Adria; Lewis, Gary F

2011-03-01

Chronically elevated free fatty acids contribute to insulin resistance and pancreatic β-cell failure. Among numerous potential factors, the involvement of endoplasmic reticulum (ER) stress has been postulated to play a mechanistic role. Here we examined the efficacy of the chemical chaperone, sodium phenylbutyrate (PBA), a drug with known capacity to reduce ER stress in animal models and in vitro, on lipid-induced insulin resistance and β-cell dysfunction in humans. Eight overweight or obese nondiabetic men underwent four studies each, in random order, 4 to 6 weeks apart. Two studies were preceded by 2 weeks of oral PBA (7.5 g/day), followed by a 48-h i.v. infusion of intralipid/heparin or saline, and two studies were preceded by placebo treatment, followed by similar infusions. Insulin secretion rates (ISRs) and sensitivity (S(I)) were assessed after the 48-h infusions by hyperglycemic and hyperinsulinemic-euglycemic clamps, respectively. Lipid infusion reduced S(I), which was significantly ameliorated by pretreatment with PBA. Absolute ISR was not affected by any treatment; however, PBA partially ameliorated the lipid-induced reduction in the disposition index (DI = ISR × S(I)), indicating that PBA prevented lipid-induced β-cell dysfunction. These results suggest that PBA may provide benefits in humans by ameliorating the insulin resistance and β-cell dysfunction induced by prolonged elevation of free fatty acids.

Type 1 Ig-E mediated allergy to human insulin, insulin analogues and beta-lactam antibiotics Hipersensibilidade imediata a insulina humana, análogos de insulina e a antibióticos beta-lactâmicos

Directory of Open Access Journals (Sweden)

Pedro Andrade

2012-12-01

Full Text Available Insulin, a crucial therapeutic agent for diabetes mellitus, has been rarely associated with hypersensitivity events. We present a 69-year-old type-2 diabetic patient with urticariform lesions on the sites of subcutaneous injection of insulin. The patient denied any known allergies, except for an unspecific cutaneous reaction after intramuscular penicillin administration in childhood. Prick tests revealed positive reactions to all tested human insulins and insulin analogues. Serum IgE levels were above normal range and RAST tests were positive for human, bovine and porcine insulins, as well as beta-lactams. Type 1 IgEmediated allergy to insulin analogues demands a prompt diagnosis and represents a significant therapeutic challenge in diabetic patients.A insulina é um agente indispensável para o controlo da diabetes mellitus. Os efeitos adversos da sua administração, em particular fenómenos de hipersensibilidade, são raros. Apresentamos um doente de 69 anos, diabético do tipo 2, com episódios recorrentes de lesões urticariformes nos locais de administração subcutânea de insulina. Negava alergias medicamentosas, à excepção de reacção não especificada na infância após penicilina intramuscular. Foram realizados testes cutâneos por puntura (prick tests com diversos tipos de insulina humana e análogos, todos com reacções positivas, associando elevação dos níveis de IgE sérica e provas RAST positivas para as insulinas humana, bovina e porcina e para os antibióticos beta-lactâmicos. A alergia a análogos de insulina exige um diagnóstico precoce, originando um desafio terapêutico importante no doente diabético.

A human beta cell line with drug inducible excision of immortalizing transgenes

Science.gov (United States)

Benazra, Marion; Lecomte, Marie-José; Colace, Claire; Müller, Andreas; Machado, Cécile; Pechberty, Severine; Bricout-Neveu, Emilie; Grenier-Godard, Maud; Solimena, Michele; Scharfmann, Raphaël; Czernichow, Paul; Ravassard, Philippe

2015-01-01

Objectives Access to immortalized human pancreatic beta cell lines that are phenotypically close to genuine adult beta cells, represent a major tool to better understand human beta cell physiology and develop new therapeutics for Diabetes. Here we derived a new conditionally immortalized human beta cell line, EndoC-βH3 in which immortalizing transgene can be efficiently removed by simple addition of tamoxifen. Methods We used lentiviral mediated gene transfer to stably integrate a tamoxifen inducible form of CRE (CRE-ERT2) into the recently developed conditionally immortalized EndoC βH2 line. The resulting EndoC-βH3 line was characterized before and after tamoxifen treatment for cell proliferation, insulin content and insulin secretion. Results We showed that EndoC-βH3 expressing CRE-ERT2 can be massively amplified in culture. We established an optimized tamoxifen treatment to efficiently excise the immortalizing transgenes resulting in proliferation arrest. In addition, insulin expression raised by 12 fold and insulin content increased by 23 fold reaching 2 μg of insulin per million cells. Such massive increase was accompanied by enhanced insulin secretion upon glucose stimulation. We further observed that tamoxifen treated cells maintained a stable function for 5 weeks in culture. Conclusions EndoC βH3 cell line represents a powerful tool that allows, using a simple and efficient procedure, the massive production of functional non-proliferative human beta cells. Such cells are close to genuine human beta cells and maintain a stable phenotype for 5 weeks in culture. PMID:26909308

From Human Mesenchymal Stem Cells to Insulin-Producing Cells: Comparison between Bone Marrow- and Adipose Tissue-Derived Cells

Directory of Open Access Journals (Sweden)

Mahmoud M. Gabr

2017-01-01

Full Text Available The aim of this study is to compare human bone marrow-derived mesenchymal stem cells (BM-MSCs and adipose tissue-derived mesenchymal stem cells (AT-MSCs, for their differentiation potentials to form insulin-producing cells. BM-MSCs were obtained during elective orthotopic surgery and AT-MSCs from fatty aspirates during elective cosmetics procedures. Following their expansion, cells were characterized by phenotyping, trilineage differentiation ability, and basal gene expression of pluripotency genes and for their metabolic characteristics. Cells were differentiated according to a Trichostatin-A based protocol. The differentiated cells were evaluated by immunocytochemistry staining for insulin and c-peptide. In addition the expression of relevant pancreatic endocrine genes was determined. The release of insulin and c-peptide in response to a glucose challenge was also quantitated. There were some differences in basal gene expression and metabolic characteristics. After differentiation the proportion of the resulting insulin-producing cells (IPCs, was comparable among both cell sources. Again, there were no differences neither in the levels of gene expression nor in the amounts of insulin and c-peptide release as a function of glucose challenge. The properties, availability, and abundance of AT-MSCs render them well-suited for applications in regenerative medicine. Conclusion. BM-MSCs and AT-MSCs are comparable regarding their differential potential to form IPCs. The availability and properties of AT-MSCs render them well-suited for applications in regenerative medicine.

The effect of exercise on the absorption of inhaled human insulin via the AERx(R) iDMS in people with type 1 diabetes

DEFF Research Database (Denmark)

Petersen, Astrid Heide; Kohler, G; Korsatko, S

2007-01-01

OBJECTIVE - This study investigated the effect of moderate exercise on the absorption of inhaled insulin via the AERx(R) insulin Diabetes Management System (iDMS). RESEARCH DESIGN AND METHODS - In this randomized, open-label, 4-period cross-over, glucose clamp study 23 non-smoking subjects...... with type 1 diabetes received a dose of 0.19 units/kg inhaled human insulin followed in random order by either 1) no exercise (NOEX), or 30 min exercise starting 2) 30 min after dosing (EX30), 3) 120 min after dosing (EX120), or 4) 240 min after dosing (EX240). RESULTS - Exercise changed the shape...... of the free plasma insulin curves, but compared to NOEX the AUC(ins) for the first 2 hours after start of exercise was unchanged for EX30 and EX240, while 15% decreased for EX120 (p

Reevaluation of Fatty acid receptor 1 (FFAR1/GPR40) as drug target for the stimulation of insulin secretion in humans

DEFF Research Database (Denmark)

Wagner, Robert; Kaiser, Gabriele; Gerst, Felicia

2013-01-01

The role of free fatty acid receptor 1 (FFAR1/GPR40) in glucose homeostasis is still incompletely understood. Small receptor agonists stimulating insulin secretion are under investigation for the treatment of type 2 diabetes. Surprisingly, genome-wide association studies did not discover diabetes...... risk variants in FFAR1. We reevaluated the role of FFAR1 in insulin secretion using a specific agonist, FFAR1-knockout mice and human islets. Nondiabetic individuals were metabolically phenotyped and genotyped. In vitro experiments indicated that palmitate and a specific FFAR1-agonist, TUG-469......, stimulate glucose-induced insulin secretion through FFAR1. The pro-apoptotic effect of chronic exposure of beta-cells to palmitate was independent of FFAR1. TUG-469 was protective, while inhibition of FFAR1 promoted apoptosis. In accordance with the pro-apoptotic effect of palmitate, in vivo crosssectional...

Affinity-purified human interleukin I is cytotoxic to isolated islets of Langerhans

DEFF Research Database (Denmark)

Mandrup-Poulsen, T; Bendtzen, K; Nerup, J

1986-01-01

Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets. These e......Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets...

Characterisation of adiponectin multimers and the IGF axis in humans with a heterozygote mutation in the tyrosine kinase domain of the insulin receptor gene

DEFF Research Database (Denmark)

Højlund, Kurt; Beck-Nielsen, Henning; Flyvbjerg, Allan

2012-01-01

Objective: Low levels of adiponectin, IGF-binding protein (IGFBP)-1, and IGFBP-2, and high levels of leptin correlate with several indices of insulin resistance and risk of type 2 diabetes. However, in insulin receptoropathies plasma adiponectin is paradoxically increased despite severe insulin...... resistance, whereas the IGF-axis is sparsely described. Here, we aimed to characterize the multimeric distribution of adiponectin and the IGF-axis in humans with a heterozygous INSR mutation (Arg1174Gln).Methods: Blood samples obtained in six Arg1174Gln-carriers and 10 lean, healthy controls before and after...... an euglycemic-hyperinsulinemic clamp were examined for plasma adiponectin multimers, leptin, total IGF-I, IGF-II, free IGF-I, IGFBP-1 and IGFBP-2.Results: Despite 10-fold elevated fasting insulin and marked insulin resistance in Arg1174Gln-carriers, the levels of total adiponectin, leptin, IGFBP-1 and IGFBP-2...

Acute exercise and physiological insulin induce distinct phosphorylation signatures on TBC1D1 and TBC1D4 in human skeletal muscle

DEFF Research Database (Denmark)

Treebak, Jonas Thue; Pehmøller, Christian; Kristensen, Jonas Møller

2014-01-01

We investigated the phosphorylation signatures of two Rab GTPase activating proteins TBC1D1 and TBC1D4 in human skeletal muscle in response to physical exercise and physiological insulin levels induced by a carbohydrate rich meal using a paired experimental design. Eight healthy male volunteers e...

Alterations in human milk leptin and insulin are associated with early changes in the infant intestinal microbiome.

Science.gov (United States)

Lemas, Dominick J; Young, Bridget E; Baker, Peter R; Tomczik, Angela C; Soderborg, Taylor K; Hernandez, Teri L; de la Houssaye, Becky A; Robertson, Charles E; Rudolph, Michael C; Ir, Diana; Patinkin, Zachary W; Krebs, Nancy F; Santorico, Stephanie A; Weir, Tiffany; Barbour, Linda A; Frank, Daniel N; Friedman, Jacob E

2016-05-01

Increased maternal body mass index (BMI) is a robust risk factor for later pediatric obesity. Accumulating evidence suggests that human milk (HM) may attenuate the transfer of obesity from mother to offspring, potentially through its effects on early development of the infant microbiome. Our objective was to identify early differences in intestinal microbiota in a cohort of breastfeeding infants born to obese compared with normal-weight (NW) mothers. We also investigated relations between HM hormones (leptin and insulin) and both the taxonomic and functional potentials of the infant microbiome. Clinical data and infant stool and fasting HM samples were collected from 18 NW [prepregnancy BMI (in kg/m(2)) obese (prepregnancy BMI >30.0) mothers and their exclusively breastfed infants at 2 wk postpartum. Infant body composition at 2 wk was determined by air-displacement plethysmography. Infant gastrointestinal microbes were estimated by using 16S amplicon and whole-genome sequencing. HM insulin and leptin were determined by ELISA; short-chain fatty acids (SCFAs) were measured in stool samples by using gas chromatography. Power was set at 80%. Infants born to obese mothers were exposed to 2-fold higher HM insulin and leptin concentrations (P obesity may adversely affect the early infant intestinal microbiome, HM insulin and leptin are independently associated with beneficial microbial metabolic pathways predicted to increase intestinal barrier function and reduce intestinal inflammation. This trial was registered at clinicaltrials.gov as NCT01693406. © 2016 American Society for Nutrition.

Central insulin-like growth factor-1 (IGF-1) restores whole-body insulin action in a model of age-related insulin resistance and IGF-1 decline.

Science.gov (United States)

Huffman, Derek M; Farias Quipildor, Gabriela; Mao, Kai; Zhang, Xueying; Wan, Junxiang; Apontes, Pasha; Cohen, Pinchas; Barzilai, Nir

2016-02-01

Low insulin-like growth factor-1 (IGF-1) signaling is associated with improved longevity, but is paradoxically linked with several age-related diseases in humans. Insulin-like growth factor-1 has proven to be particularly beneficial to the brain, where it confers protection against features of neuronal and cognitive decline. While aging is characterized by central insulin resistance in the face of hyperinsulinemia, the somatotropic axis markedly declines in older humans. Thus, we hypothesized that increasing IGF-1 in the brain may prove to be a novel therapeutic alternative to overcome central insulin resistance and restore whole-body insulin action in aging. Utilizing hyperinsulinemic-euglycemic clamps, we show that old insulin-resistant rats with age-related declines in IGF-1 level demonstrate markedly improved whole-body insulin action, when treated with central IGF-1, as compared to central vehicle or insulin (P IGF-1, but not insulin, suppressed hepatic glucose production and increased glucose disposal rates in aging rats (P IGF-1 action in the brain and periphery provides a 'balance' between its beneficial and detrimental actions. Therefore, we propose that strategies aimed at 'tipping the balance' of IGF-1 action centrally are the optimal approach to achieve healthy aging and longevity in humans. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Ghrelin- and GH-induced insulin resistance

DEFF Research Database (Denmark)

Vestergaard, Esben Thyssen; Krag, Morten B; Poulsen, Morten M

2013-01-01

Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects.......Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects....

Monomeric insulins and their experimental and clinical implications.

Science.gov (United States)

Brange, J; Owens, D R; Kang, S; Vølund, A

1990-09-01

Due to the inherent pharmacokinetic properties of available insulins, normoglycemia is rarely, if ever, achieved in insulin-dependent diabetic patients without compromising their quality of life. Subcutaneous insulin absorption is influenced by many factors, among which the associated state of insulin (hexameric) in pharmaceutical formulation may be of importance. This review describes the development of a series of human insulin analogues with reduced tendency to self-association that, because of more rapid absorption, are better suited to meal-related therapy. DNA technology has made it possible to prepare insulins that remain dimeric or even monomeric at high concentration by introducing one or a few amino acid substitutions into human insulin. These analogues were characterized and used for elucidating the mechanisms involved in subcutaneous absorption and were investigated in preliminary clinical studies. Their relative receptor binding and in vitro potency (free-fat cell assay), ranging from 0.05 to 600% relative to human insulin, were strongly correlated (r = 0.97). In vivo, most of the analogues exhibited approximately 100% activity, explainable by a dominating receptor-mediated clearance. This was confirmed by clamp studies in which correlation between receptor binding and clearance was observed. Thus, an analogue with reduced binding and clearance gives higher circulating concentrations, counterbalancing the reduced potency at the cellular level. Absorption studies in pigs revealed a strong inverse correlation (r = 0.96) between the rate of subcutaneous absorption and the mean association state of the insulin analogues. These studies also demonstrated that monomeric insulins were absorbed three times faster than human insulin. In healthy subjects, rates of disappearance from subcutis were two to three times faster for dimeric and monomeric analogues than for human insulin. Concomitantly, a more rapid rise in plasma insulin concentration and an earlier

Two Cases of Allergy to Insulin in Gestational Diabetes

Directory of Open Access Journals (Sweden)

Gi Jun Kim

2015-09-01

Full Text Available Allergic reaction to insulin is uncommon since the introduction of human recombinant insulin preparations and is more rare in pregnant than non-pregnant females due to altered immune reaction during pregnancy. Herein, we report two cases of allergic reaction to insulin in gestational diabetes that were successfully managed. One case was a 33-year-old female using isophane-neutral protamine Hagedorn human insulin and insulin lispro. She experienced dyspnea, cough, urticaria and itching sensation at the sites of insulin injection immediately after insulin administration. We discontinued insulin therapy and started oral hypoglycemic agents with metformin and glibenclamide. The other case was a 32-year-old female using insulin lispro and insulin detemer. She experienced pruritus and burning sensation and multiple nodules at the sites of insulin injection. We changed the insulin from insulin lispro to insulin aspart. Assessments including immunoglobulin E (IgE, IgG, eosinophil, insulin antibody level and skin biopsy were performed. In the two cases, the symptoms were resolved after changing the insulin to oral agents or other insulin preparations. We report two cases of allergic reaction to human insulin in gestational diabetes due to its rarity.

Short-term effects of recombinant human growth hormone and feeding on gluconeogenesis in humans

Science.gov (United States)

After a short-term fast, lactating women have increased rates of glucose production but not gluconeogenesis (GNG) despite relative hypoinsulinemia. We explored the effects of non-insulin-dependent increase in glucose utilization and recombinant human growth hormone (rhGH) on glucose production, glyc...

Insulin-like growth factor I enhances collagen synthesis in engineered human tendon tissue

DEFF Research Database (Denmark)

Herchenhan, Andreas; Bayer, Monika L.; Eliasson, Pernilla

2015-01-01

OBJECTIVE: Isolated human tendon cells form 3D tendon constructs that demonstrate collagen fibrillogenesis and feature structural similarities to tendon when cultured under tensile load. The exact role of circulating growth factors for collagen formation in tendon is sparsely examined. We...... investigated the influence of insulin-like growth factor I (IGF-I) on tendon construct formation in 3D cell culture. DESIGN: Tendon constructs were grown in 0.5 or 10% FBS with or without IGF-I (250 mg/ml) supplementation. Collagen content (fluorometric), mRNA levels (PCR) and fibril diameter (transmission...... electron microscopy) were determined at 7, 10, 14, 21 and 28 days. RESULTS: IGF-I revealed a stimulating effect on fibril diameter (up to day 21), mRNA for collagen (to day 28), tenomodulin (to day 28) and scleraxis (at days 10 and 14), and on overall collagen content. 10% FBS diminished the development...

Bariatric surgery in morbidly obese insulin resistant humans normalises insulin signalling but not insulin-stimulated glucose disposal.

Directory of Open Access Journals (Sweden)

Mimi Z Chen

Full Text Available Weight-loss after bariatric surgery improves insulin sensitivity, but the underlying molecular mechanism is not clear. To ascertain the effect of bariatric surgery on insulin signalling, we examined glucose disposal and Akt activation in morbidly obese volunteers before and after Roux-en-Y gastric bypass surgery (RYGB, and compared this to lean volunteers.The hyperinsulinaemic euglycaemic clamp, at five infusion rates, was used to determine glucose disposal rates (GDR in eight morbidly obese (body mass index, BMI=47.3 ± 2.2 kg/m(2 patients, before and after RYGB, and in eight lean volunteers (BMI=20.7 ± 0.7 kg/m2. Biopsies of brachioradialis muscle, taken at fasting and insulin concentrations that induced half-maximal (GDR50 and maximal (GDR100 GDR in each subject, were used to examine the phosphorylation of Akt-Thr308, Akt-473, and pras40, in vivo biomarkers for Akt activity.Pre-operatively, insulin-stimulated GDR was lower in the obese compared to the lean individuals (P<0.001. Weight-loss of 29.9 ± 4 kg after surgery significantly improved GDR50 (P=0.004 but not GDR100 (P=0.3. These subjects still remained significantly more insulin resistant than the lean individuals (p<0.001. Weight loss increased insulin-stimulated skeletal muscle Akt-Thr308 and Akt-Ser473 phosphorylation, P=0.02 and P=0.03 respectively (MANCOVA, and Akt activity towards the substrate PRAS40 (P=0.003, MANCOVA, and in contrast to GDR, were fully normalised after the surgery (obese vs lean, P=0.6, P=0.35, P=0.46, respectively.Our data show that although Akt activity substantially improved after surgery, it did not lead to a full restoration of insulin-stimulated glucose disposal. This suggests that a major defect downstream of, or parallel to, Akt signalling remains after significant weight-loss.

The Chromium is an essential element in the human

International Nuclear Information System (INIS)

Alvarado Gamez, A.; Blanco Saenz, R.; Mora Morales, E.

2002-01-01

The Chromium is an essential element for human and animals, because it a preponderant function in the insulin metabolism as a glucose tolerance factor (GTF). The deficiency of chromium engenders a deterioration in the glucose metabolism due to bad efficiency of insulin. Because the importance of this element an exhaustive reference review was made and this presents some studies realized in laboratory animals and in human beings where it is prove with resuits the effect of chromium over the improvement of patients with non-insulin dependant diabetes. Three substances are presented as chromium active biological forms: a material rich in chromium known as glucose tolerance factor, chromium picolinate and a substance of low molecular weight LMWCr in its forms of apo and holo that contains chromium and it links the insulin receptor and improves its activity. Also this paper presents information about the condition of diabetes in Costa Rica. (Author) [es

Optimization of codon composition and regulatory elements for expression of human insulin like growth factor-1 in transgenic chloroplasts and evaluation of structural identity and function.

Science.gov (United States)

Daniell, Henry; Ruiz, Gricel; Denes, Bela; Sandberg, Laurence; Langridge, William

2009-04-03

Transgenic chloroplasts are potential bioreactors for recombinant protein production, especially for achievement of high levels of protein expression and proper folding. Production of therapeutic proteins in leaves provides transgene containment by elimination of reproductive structures. Therefore, in this study, human Insulin like Growth Factor-1 is expressed in transgenic chloroplasts for evaluation of structural identity and function. Expression of the synthetic Insulin like Growth Factor 1 gene (IGF-1s, 60% AT) was observed in transformed E. coli. However, no native IGF-1 gene (IGF-1n, 41% AT) product was detected in the western blots in E. coli. Site-specific integration of the transgenes into the tobacco chloroplast genome was confirmed after transformation using PCR. Southern blot analysis confirmed that the transgenic lines were homoplasmic. The transgenic plant lines had IGF-1s expression levels of 11.3% of total soluble protein (TSP). The IGF-1n plants contained 9.5% TSP as IGF-1n, suggesting that the chloroplast translation machinery is more flexible than E. coli in codon preference and usage. The expression of IGF-1 was increased up to 32% TSP under continuous illumination by the chloroplast light regulatory elements. IgG-Sepharose affinity column chromatographic separation of Z domain containing chloroplast derived IGF-1 protein, single and two dimensional electrophoresis methods and mass spectrometer analysis confirmed the identity of human IGF-1 in transgenic chloroplasts. Two spots analyzed from 2-D focusing/phoresis acrylamide gel showed the correct amino acid sequence of human IGF-1 and the S. aureus Z-tag. Cell proliferation assays in human HU-3 cells demonstrated the biological activity of chloroplast derived IGF-1 even in the presence of the S. aureus Z tag. This study demonstrates that the human Insulin like Growth Factor-1 expressed in transgenic chloroplasts is identical to the native protein and is fully functional. The ability to use plant

Partial characterization of insulin-like growth factor I in primary human lung cancers using immunohistochemical and receptor autoradiographic techniques

International Nuclear Information System (INIS)

Shigematsu, K.; Kataoka, Y.; Kamio, T.; Kurihara, M.; Niwa, M.; Tsuchiyama, H.

1990-01-01

We investigated primary human lung cancers resected surgically or obtained at autopsy. Included were squamous cell carcinoma (SQC) (five cases), adenocarcinoma (ADC) (six cases), large cell carcinoma (LCC) (four cases), and small cell carcinoma (SCC) (two cases). The objective of the study was to search for the presence of insulin-like growth factor I (IGF-I)-like immunoreactivity using immunohistochemical staining and for the localization of IGF-I binding sites, using in vitro quantitative receptor autoradiographic techniques. IGF-I-like immunostaining was present in all cases of SQC, ADC, and LCC, but not in cases of SCC. Strong immunostaining was observed in cases of SQC. On the other hand, ADC and LCC tissues showed a moderate or weak staining. Specific binding sites for IGF-I were present in all cases of SQC, ADC, LCC, and SCC examined. High densities of 125I-IGF-I binding sites were localized in cases of SQC and SCC. Low to high densities of the binding sites were found in LCC. Cases of ADC showed low densities of 125I-IGF-I binding sites. Specific binding obtained at a concentration of 80 pM 125I-IGF-I was competitively displaced by unlabeled IGF-I, with a 50% inhibitory concentration value of 1.84 +/- 0.31 x 10(-10) mol, whereas human insulin was much less potent in displacing the binding. This specificity profile is consistent with characteristics of IGF-I receptors. Scatchard analysis showed the presence of a single class of high affinity binding sites for IGF-I, with a Kd of approximately 1 nmol. Thus, the possibility that IGF-I may play a role in the growth of human lung cancers would have to be considered

The genetic component of human longevity

DEFF Research Database (Denmark)

Dato, Serena; Thinggaard, Mette Sørensen; De Rango, Francesco

2018-01-01

In human longevity studies, single nucleotide polymorphism (SNP) analysis identified a large number of genetic variants with small effects, yet not easily replicable in different populations. New insights may come from the combined analysis of different SNPs, especially when grouped by metabolic...... pathway. We applied this approach to study the joint effect on longevity of SNPs belonging to three candidate pathways, the insulin/insulin-like growth factor signalling (IIS), DNA repair and pro/antioxidant. We analysed data from 1,058 tagging SNPs in 140 genes, collected in 1825 subjects (1......, was further found influencing longitudinal survival in nonagenarian females (p = .026). Results here presented highlight the validity of SNP-SNP interactions analyses for investigating the genetics of human longevity, confirming previously identified markers but also pointing to novel genes as central nodes...

Use of magnesium silicate as a selective absorbent in radioimmunological method of determination of insulin level in human serum

Energy Technology Data Exchange (ETDEWEB)

Bogoniowska, Z; Stelmasiak, T [Wojskowy Instytut Higieny i Epidemiologii, Warsaw (Poland)

1974-01-01

The authors present a radioimmunological method for determination of insulin (IRI) level in the human serum using magnesium silicate (talc) as adsorbent. The method is based on the phenomenon of selective adsorption of the free radioactive hormone. The optimal parameters for the method were determined. The serum level of IRI in clinically healthy subjects after oral glucose loading was established. The obtained results were compared with the results obtained by the radioimmunological method of double antibodies in stochastically grouped samples.

GH receptor blocker administration and muscle-tendon collagen synthesis in humans

DEFF Research Database (Denmark)

Nielsen, Rie Harboe; Doessing, Simon; Goto, Kazushige

2011-01-01

The growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis stimulates collagen synthesis in tendon and skeletal muscle, but no studies have investigated the effect of reducing IGF-I on collagen synthesis in healthy humans.......The growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis stimulates collagen synthesis in tendon and skeletal muscle, but no studies have investigated the effect of reducing IGF-I on collagen synthesis in healthy humans....

Increased interaction with insulin receptor substrate 1, a novel abnormality in insulin resistance and type 2 diabetes

DEFF Research Database (Denmark)

Caruso, Michael; Ma, Danjun; Msallaty, Zaher

2014-01-01

Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health...... in obesity and T2D in humans, provides new insights into the molecular mechanism of insulin resistance and identifies new targets for T2D drug development....... and disease conditions. We used a proteomic approach to assess IRS1 interaction partners in skeletal muscle from lean healthy control subjects (LCs), obese insulin-resistant nondiabetic control subjects (OCs), and participants with T2D before and after insulin infusion. We identified 113 novel endogenous IRS1...

Human pancreatic islet-derived extracellular vesicles modulate insulin expression in 3D-differentiating iPSC clusters.

Directory of Open Access Journals (Sweden)

Diana Ribeiro

Full Text Available It has been suggested that extracellular vesicles (EVs can mediate crosstalk between hormones and metabolites within pancreatic tissue. However, the possible effect of pancreatic EVs on stem cell differentiation into pancreatic lineages remains unknown. Herein, human islet-derived EVs (h-Islet-EVs were isolated, characterized and subsequently added to human induced pluripotent stem cell (iPSC clusters during pancreatic differentiation. The h-islet-EVs had a mean size of 117±7 nm and showed positive expression of CD63 and CD81 EV markers as measured by ELISA. The presence of key pancreatic transcription factor mRNA, such as NGN3, MAFA and PDX1, and pancreatic hormone proteins such as C-peptide and glucagon, were confirmed in h-Islet-EVs. iPSC clusters were differentiated in suspension and at the end stages of the differentiation protocol, the mRNA expression of the main pancreatic transcription factors and pancreatic hormones was increased. H-Islet-EVs were supplemented to the iPSC clusters in the later stages of differentiation. It was observed that h-Islet-EVs were able to up-regulate the intracellular levels of C-peptide in iPSC clusters in a concentration-dependent manner. The effect of h-Islet-EVs on the differentiation of iPSC clusters cultured in 3D-collagen hydrogels was also assessed. Although increased mRNA expression for pancreatic markers was observed when culturing the iPSC clusters in 3D-collagen hydrogels, delivery of EVs did not affect the insulin or C-peptide intracellular content. Our results provide new information on the role of h-Islet-EVs in the regulation of insulin expression in differentiating iPSC clusters, and are highly relevant for pancreatic tissue engineering applications.

IGF-II receptors and IGF-II-stimulated glucose transport in human fat cells

International Nuclear Information System (INIS)

Sinha, M.K.; Buchanan, C.; Raineri-Maldonado, C.; Khazanie, P.; Atkinson, S.; DiMarchi, R.; Caro, J.F.

1990-01-01

Insulin-like growth factor II (IGF-II) receptors have been described in rat but not in human adipocytes. In both species, IGF-II has been reported to stimulate glucose transport by interacting with the insulin receptor. In this study, we have unequivocally demonstrated the presence of IGF-II receptors in human adipocytes. 125I-labeled IGF-II specifically binds to intact adipocytes, membranes, and lectin-purified detergent solubilized extracts. Through the use of 0.5 mM disuccinimidyl suberate, 125I-IGF-II is cross-linked to a 260-kDa protein that is identified as the IGF-II receptor by displacement experiments with unlabeled IGF-II, IGF-I, and insulin and either by immunoprecipitation or by Western blot analysis with mannose 6-phosphate receptor antibodies. The concentrations of IGF-II required for half-maximal and maximal stimulation of glucose transport in human adipocytes are 35 and 100 times more than that of insulin. The possibility of IGF-II stimulating glucose transport by interacting predominantly with the insulin receptor is suggested by the following: (1) the concentration of IGF-II that inhibits half of insulin binding is only 20 times more than that of insulin; (2) the lack of an additive effect of IGF-II and insulin for maximal stimulation of glucose transport; (3) the ability of monoclonal insulin receptor antibodies to decrease glucose transport stimulated by submaximal concentrations of both IGF-II and insulin; and (4) the ability of IGF-II to stimulate insulin receptor autophosphorylation albeit at a reduced potency when compared with insulin

Insulin analogues with improved absorption characteristics.

Science.gov (United States)

Brange, J; Hansen, J F; Langkjaer, L; Markussen, J; Ribel, U; Sørensen, A R

1992-01-01

The insulin preparations available today are not ideal for therapy as s.c. injection does not provide a physiological insulin profile. With the aim to improve the absorption properties recombinant DNA technology has been utilized to design novel insulin molecules with changed physico-chemical characteristics and hence altered subcutaneous absorption kinetics. Soluble, long-acting human insulin analogues in which the isoelectric point has been increased from 5.4 to approx. 7 are absorbed very slowly, providing a more constant basal insulin delivery with lower day-to-day variation than present protracted preparations. In addition they have better storage stability. Rapid-acting human insulin analogues with largely reduced self-association are absorbed substantially faster from subcutaneous tissue than current regular insulin and thus are better suited for bolus injection. The absorption kinetics of these analogues have been able to explain the mechanism behind the dose effect on insulin absorption rate.

Relationship of insulin, glucose, leptin, IL-6 and TNF-α in human breast milk with infant growth and body composition.

Science.gov (United States)

Fields, D A; Demerath, E W

2012-08-01

Numerous appetite, growth, obesity-related hormones and inflammatory factors are found in human breast-milk, but there is little evidence on their relationship with infant body composition. OBJECTVIE: The purpose of the present cross-sectional pilot study was to assess the cross-sectional associations of appetite-regulating hormones and growth factors (leptin, insulin and glucose) and inflammatory factors (interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α)) in human breast-milk with infant size, adiposity, and lean tissue at 1-month of age in healthy term infants. Human breast-milk was collected from nineteen exclusively breast-feeding mothers using one full breast expression between 8:00 and 10:00 a.m. The milk was then mixed, aliquoted, stored at -80°C and then centrifuged to remove the milk fat, prior to analyses using commercially available immunoassay kits; milk analytes were natural log transformed prior to analysis. Infant body composition was assessed using a Lunar iDXA v11-30.062 scanner (Infant whole body analysis enCore 2007 software, GE, Fairfield, CT). Maternal pre-pregnancy BMI was positively associated with milk leptin concentration (P = 0.0027), and so maternal-BMI-adjusted Spearman correlations were examined between breast-milk analytes and infant growth and body composition variables. As previously reported, greater milk leptin was associated with lower BMIZ (BMI-for-age z-score based on WHO 2006 growth charts; r = -0.54, P = 0.03). Glucose was positively associated with relative weight (r = 0.6, P = 0.01), and both fat and lean mass (0.43-0.44, P milk insulin were associated with lower infant weight, relative weight, and lean mass (r = -0.49-0.58, P milk IL-6 was associated with lower relative weight, weight gain, percent fat, and fat mass (r = -0.55-0.70, P milk concentrations of insulin, glucose, IL-6 and TNF-α, in addition to leptin, may be bioactive and differentially influence the accrual of fat and lean body mass. © 2012

Histochemical evidence for the differential surface labeling, uptake, and intracellular transport of a colloidal gold-labeled insulin complex by normal human blood cells.

Science.gov (United States)

Ackerman, G A; Wolken, K W

1981-10-01

A colloidal gold-labeled insulin-bovine serum albumin (GIA) reagent has been developed for the ultrastructural visualization of insulin binding sites on the cell surface and for tracing the pathway of intracellular insulin translocation. When applied to normal human blood cells, it was demonstrated by both visual inspection and quantitative analysis that the extent of surface labeling, as well as the rate and degree of internalization of the insulin complex, was directly related to cell type. Further, the pathway of insulin (GIA) transport via round vesicles and by tubulo-vesicles and saccules and its subsequent fate in the hemic cells was also related to cell variety. Monocytes followed by neutrophils bound the greatest amount of labeled insulin. The majority of lymphocytes bound and internalized little GIA, however, between 5-10% of the lymphocytes were found to bind considerable quantities of GIA. Erythrocytes rarely bound the labeled insulin complex, while platelets were noted to sequester large quantities of the GIA within their extracellular canalicular system. GIA uptake by the various types of leukocytic cells appeared to occur primarily by micropinocytosis and by the direct opening of cytoplasmic tubulo-vesicles and saccules onto the cell surface in regions directly underlying surface-bound GIA. Control procedures, viz., competitive inhibition of GIA labeling using an excess of unlabeled insulin in the incubation medium, preincubation of the GIA reagent with an antibody directed toward porcine insulin, and the incorporation of 125I-insulin into the GIA reagent, indicated the specificity and selectivity of the GIA histochemical procedure for the localization of insulin binding sites.

Histochemical evidence for the differential surface labeling, uptake, and intracellular transport of a colloidal gold-labeled insulin complex by normal human blood cells

International Nuclear Information System (INIS)

Ackerman, G.A.; Wolken, K.W.

1981-01-01

A colloidal gold-labeled insulin-bovine serum albumin (GIA) reagent has been developed for the ultrastructural visualization of insulin binding sites on the cell surface and for tracing the pathway of intracellular insulin translocation. When applied to normal human blood cells, it was demonstrated by both visual inspection and quantitative analysis that the extent of surface labeling, as well as the rate and degree of internalization of the insulin complex, was directly related to cell type. Further, the pathway of insulin (GIA) transport via round vesicles and by tubulo-vesicles and saccules and its subsequent fate in the hemic cells was also related to cell variety. Monocytes followed by neutrophils bound the greatest amount of labeled insulin. The majority of lymphocytes bound and internalized little GIA, however, between 5-10% of the lymphocytes were found to bind considerable quantities of GIA. Erythrocytes rarely bound the labeled insulin complex, while platelets were noted to sequester large quantities of the GIA within their extracellular canalicular system. GIA uptake by the various types of leukocytic cells appeared to occur primarily by micropinocytosis and by the direct opening of cytoplasmic tubulo-vesicles and saccules onto the cell surface in regions directly underlying surface-bound GIA. Control procedures, viz., competitive inhibition of GIA labeling using an excess of unlabeled insulin in the incubation medium, preincubation of the GIA reagent with an antibody directed toward porcine insulin, and the incorporation of 125I-insulin into the GIA reagent, indicated the specificity and selectivity of the GIA histochemical procedure for the localization of insulin binding sites

Activated α2-macroglobulin binding to human prostate cancer cells triggers insulin-like responses.

Science.gov (United States)

Misra, Uma Kant; Pizzo, Salvatore Vincent

2015-04-10

Ligation of cell surface GRP78 by activated α2-macroglobulin (α2M*) promotes cell proliferation and suppresses apoptosis. α2M*-treated human prostate cancer cells exhibit a 2-3-fold increase in glucose uptake and lactate secretion, an effect similar to insulin treatment. In both α2M* and insulin-treated cells, the mRNA levels of SREBP1-c, SREBP2, fatty-acid synthase, acetyl-CoA carboxylase, ATP citrate lyase, and Glut-1 were significantly increased together with their protein levels, except for SREBP2. Pretreatment of cells with α2M* antagonist antibody directed against the carboxyl-terminal domain of GRP78 blocks these α2M*-mediated effects, and silencing GRP78 expression by RNAi inhibits up-regulation of ATP citrate lyase and fatty-acid synthase. α2M* induces a 2-3-fold increase in lipogenesis as determined by 6-[(14)C]glucose or 1-[(14)C]acetate incorporation into free cholesterol, cholesterol esters, triglycerides, free fatty acids, and phosphatidylcholine, which is blocked by inhibitors of fatty-acid synthase, PI 3-kinase, mTORC, or an antibody against the carboxyl-terminal domain of GRP78. We also assessed the incorporation of [(14)CH3]choline into phosphatidylcholine and observed similar effects. Lipogenesis is significantly affected by pretreatment of prostate cancer cells with fatostatin A, which blocks sterol regulatory element-binding protein proteolytic cleavage and activation. This study demonstrates that α2M* functions as a growth factor, leading to proliferation of prostate cancer cells by promoting insulin-like responses. An antibody against the carboxyl-terminal domain of GRP78 may have important applications in prostate cancer therapy. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Transplanted human pancreatic islets after long-term insulin independence

DEFF Research Database (Denmark)

Muller, Y D; Gupta, Shashank; Morel, P

2013-01-01

Long-term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin independe...

Effect of a sustained reduction in plasma free fatty acid concentration on insulin signalling and inflammation in skeletal muscle from human subjects.

Science.gov (United States)

Liang, Hanyu; Tantiwong, Puntip; Sriwijitkamol, Apiradee; Shanmugasundaram, Karthigayan; Mohan, Sumathy; Espinoza, Sara; Defronzo, Ralph A; Dubé, John J; Musi, Nicolas

2013-06-01

Free fatty acids (FFAs) have been implicated in the pathogenesis of insulin resistance. Reducing plasma FFA concentration in obese and type 2 diabetic (T2DM) subjects improves insulin sensitivity. However, the molecular mechanism by which FFA reduction improves insulin sensitivity in human subjects is not fully understood. In the present study, we tested the hypothesis that pharmacological FFA reduction enhances insulin action by reducing local (muscle) inflammation, leading to improved insulin signalling. Insulin-stimulated total glucose disposal (TGD), plasma FFA species, muscle insulin signalling, IBα protein, c-Jun phosphorylation, inflammatory gene (toll-like receptor 4 and monocyte chemotactic protein 1) expression, and ceramide and diacylglycerol (DAG) content were measured in muscle from a group of obese and T2DM subjects before and after administration of the antilipolytic drug acipimox for 7 days, and the results were compared to lean individuals. We found that obese and T2DM subjects had elevated saturated and unsaturated FFAs in plasma, and acipimox reduced all FFA species. Acipimox-induced reductions in plasma FFAs improved TGD and insulin signalling in obese and T2DM subjects. Acipimox increased IBα protein (an indication of decreased IB kinase-nuclear factor B signalling) in both obese and T2DM subjects, but did not affect c-Jun phosphorylation in any group. Acipimox also decreased inflammatory gene expression, although this reduction only occurred in T2DM subjects. Ceramide and DAG content did not change. To summarize, pharmacological FFA reduction improves insulin signalling in muscle from insulin-resistant subjects. This beneficial effect on insulin action could be related to a decrease in local inflammation. Notably, the improvements in insulin action were more pronounced in T2DM, indicating that these subjects are more susceptible to the toxic effect of FFAs.

Insulin action in human thighs after one-legged immobilization

DEFF Research Database (Denmark)

Richter, Erik; Kiens, Bente; Mizuno, M.

1989-01-01

Insulin action was assessed in thighs of five healthy young males who had one knee immobilized for 7 days by a splint. The splint was not worn in bed. Subjects also used crutches to prevent weight bearing of the immobilized leg. Immobilization decreased the activity of citrate synthase and 3-OH......-acyl-CoA-dehydrogenase in the vastus lateralis muscle by 9 and 14%, respectively, and thigh volume by 5%. After 7 days of immobilization, a two-step euglycemic hyperinsulinemic clamp procedure combined with arterial and bilateral femoral venous catheterization was performed. Insulin action on glucose uptake and tyrosine release...... of the thighs at mean plasma insulin concentrations of 67 (clamp step I) and 447 microU/ml (clamp step II) was decreased by immobilization, whereas immobilization did not affect insulin action on thigh exchange of free fatty acids, glycerol, O2, or potassium. Before and during the clamp step I, lactate release...

FA1 Induces Pro-Inflammatory and Anti-Adipogenic Pathways/Markers in Human Myotubes Established from Lean, Obese, and Type 2 Diabetic Subjects but Not Insulin Resistance

DEFF Research Database (Denmark)

Abdallah, Basem M; Beck-Nielsen, Henning; Gaster, Michael

2013-01-01

Aims: Delta like 1/fetal antigen 1 (Dlk1/FA1) is a protein secreted by hormone producing cells in adult human and mice that is known to inhibit adipogenesis. Recent studies demonstrated the role of Dlk1/FA1 in inducing insulin resistance in mice. To investigate the involvement of circulating Dlk1....../FA1 in insulin resistance and type 2 diabetes in human subjects, we studied the effects of chronic FA1 on the intermediary metabolism in myotubes established from lean, obese, and type 2 diabetic (T2D) subjects. Methods: Myotube cultures were established from lean and obese control subjects......, and obese T2D subjects and treated with soluble FA1 for 4 days supplemented with/without palmitate (PA). Lipid- and glucose metabolism were studied with labeled precursors while quantitative expression of genes was analyzed using real-time PCR. Results: Diabetic myotubes express significantly reduced...

The effect of 30 months of low-dose replacement therapy with recombinant human growth hormone (rhGH) on insulin and C-peptide kinetics, insulin secretion, insulin sensitivity, glucose effectiveness, and body composition in GH-deficient adults

DEFF Research Database (Denmark)

Rosenfalck, A M; Maghsoudi, S; Fisker, S

2000-01-01

The aim of the present study was to evaluate the long-term (30 months) metabolic effects of recombinant human GH (rhGH) given in a mean dose of 6.7 microg/kg x day (= 1.6 IU/day), in 11 patients with adult GH deficiency. Glucose metabolism was evaluated by an oral glucose tolerance test and an iv...... (frequently sampled iv glucose tolerance test) glucose tolerance test, and body composition was estimated by dual-energy x-ray absorptiometry. Treatment with rhGH induced persistent favorable changes in body composition, with a 10% increase in lean body mass (P ... in glucose tolerance, beta-cell response was still inappropriate. Our conclusion is that long-term rhGH-replacement therapy in GH deficiency adults induced a significant deterioration in glucose tolerance, profound changes in kinetics of C-peptide, and insulin and prehepatic insulin secretion, despite...

Differentiation of human induced pluripotent stem cells into insulin-like cell clusters with miR-186 and miR-375 by using chemical transfection.

Science.gov (United States)

Shaer, Anahita; Azarpira, Negar; Karimi, Mohammad Hosein

2014-09-01

Diabetes mellitus is characterized by either the inability to produce insulin or insensitivity to insulin secreted by the body. Islet cell replacement is an effective approach for diabetes treatment; however, it is not sufficient for all the diabetic patients. MicroRNAs (miRNAs) are a class of small noncoding RNAs that play an important role in mediating a broad and expanding range of biological activities, such as pancreas development. The present study aimed to develop a protocol to efficiently differentiate human induced pluripotent stem (iPS) cells into islet-like cell clusters (ILCs) in vitro by using miR-186 and miR-375. The human iPS colonies were transfected with hsa-miR-186 and hsa-miR-375 by using siPORT™ NeoFX™ Transfection Agent, and the differentiation was compared to controls. Total RNA was extracted 24 and 48 h after transfection. The gene expressions of insulin, NGN3, GLUT2, PAX4, PAX6, KIR6.2, NKX6.1, PDX1, Glucagon, and OCT4 were then evaluated through real-time qPCR. On the third day, the potency of the clusters was assessed in response to high glucose levels. Dithizone (DTZ) was used to identify the existence of the β-cells. Besides, the presence of insulin and NGN3 proteins was investigated by immunocytochemistry. Morphological changes were observed on the first day after the chemical transfection, and cell clusters were formed on the third day. The expression of pancreatic specific transcription factors was increased on the first day and significantly increased on the second day. The ILCs were positive for insulin and NGN3 proteins in the immunocytochemistry. Besides, the clusters were stained with DTZ and secreted insulin in glucose challenge test. Overexpression of miR-186 and miR-375 can be an alternative strategy for producing ILCs from the iPS cells in a short time. This work provides a new approach by using patient-specific iPSCs for β-cell replacement therapy in diabetic patients.

Plasma Levels of Myonectin But Not Myostatin or Fibroblast-Derived Growth Factor 21 Are Associated with Insulin Resistance in Adult Humans without Diabetes Mellitus

Directory of Open Access Journals (Sweden)

Freddy J. K. Toloza

2018-01-01

Full Text Available BackgroundMyokines are a group of protein mediators produced by skeletal muscle under stress or physical exertion. Even though their discovery and effects in cell culture and animal models of disease have elicited great enthusiasm, very little is known about their role in human metabolism. We assessed whether plasma concentrations of three known myokines [myonectin, myostatin, and fibroblast-derived growth factor 21 (FGF-21] would be associated with direct and indirect indicators of insulin resistance (IR in individuals who did not have a diagnosis of diabetes.MethodsWe studied 81 adults of both sexes comprising a wide range of body adiposity and insulin sensitivity. All participants underwent a thorough clinical assessment and a 5-point oral glucose tolerance test with calculation of multiple IR and insulin sensitivity indices. Twenty-one of them additionally underwent a hyperinsulinemic–euglycemic clamp with determination of steady-state whole-body insulin-stimulated glucose disposal (“M”. We compared plasma myokine concentrations across quartiles of IR indices and clinical IR surrogates, and explored the correlation of each myokine with the M-value.ResultsPlasma myonectin levels increased monotonically across quartiles of the incremental area under the insulin curve (higher values indicate more IR (p-trend = 0.021 and decreased monotonically across quartiles of the insulin sensitivity index (ISI – higher values indicate less IR (p-trend = 0.012. After multivariate adjustment for other relevant determinants of IR (body mass index, age, and sex, the negative association of myonectin with ISI persisted (standardized beta = −0.235, p = 0.023. Myostatin was not associated with any clinical IR indicator or direct IR index measure. In multivariate analyses, FGF-21 showed a trend toward a positive correlation with glucose disposal that did not reach statistical significance (standardized beta = 0.476, p = 0

Obesity and Low-Grade Inflammation Increase Plasma Follistatin-Like 3 in Humans

DEFF Research Database (Denmark)

Brandt, Claus; Pedersen, Maria; Rinnov, Anders

2014-01-01

, plasma leptin, fasting insulin, and HOMA B and negatively with HOMA S. Furthermore plasma fstl3 correlated positively with plasma TNF-α and IL-6 levels. Infusion of LPS and TNF-α, but not IL-6 and insulin, increased plasma fstl3 in humans. CONCLUSION: Plasma fstl3 is increased in obese subjects......BACKGROUND: Rodent models suggest that follistatin-like 3 (fstl3) is associated with diabetes and obesity. In humans, plasma fstl3 is reduced with gestational diabetes. In vitro, TNF-α induces fstl3 secretion, which suggests a link to inflammation. OBJECTIVE: To elucidate the association between...... plasma fstl3 and obesity, insulin resistance, and low-grade inflammation in humans. STUDY DESIGN: Plasma fstl3 levels were determined in a cross-sectional study including three groups: patients with type 2 diabetes, impaired glucose tolerance, and healthy controls. In addition, lipopolysaccharide (LPS...

Asymmetric dimethylarginine (ADMA) elevation and arginase up-regulation contribute to endothelial dysfunction related to insulin resistance in rats and morbidly obese humans.

Science.gov (United States)

El Assar, Mariam; Angulo, Javier; Santos-Ruiz, Marta; Ruiz de Adana, Juan Carlos; Pindado, María Luz; Sánchez-Ferrer, Alberto; Hernández, Alberto; Rodríguez-Mañas, Leocadio

2016-06-01

The presence of insulin resistance (IR) is determinant for endothelial dysfunction associated with obesity. Although recent studies have implicated the involvement of mitochondrial superoxide and inflammation in the defective nitric oxide (NO)-mediated responses and subsequent endothelial dysfunction in IR, other mechanisms could compromise this pathway. In the present study, we assessed the role of asymmetric dimethylarginine (ADMA) and arginase with respect to IR-induced impairment of endothelium-dependent vasodilatation in human morbid obesity and in a non-obese rat model of IR. We show that both increased ADMA and up-regulated arginase are determinant factors in the alteration of the l-arginine/NO pathway associated with IR in both models and also that acute treatment of arteries with arginase inhibitor or with l-arginine significantly alleviate endothelial dysfunction. These results help to expand our knowledge regarding the mechanisms of endothelial dysfunction that are related to obesity and IR and establish potential therapeutic targets for intervention. Insulin resistance (IR) is determinant for endothelial dysfunction in human obesity. Although we have previously reported the involvement of mitochondrial superoxide and inflammation, other mechanisms could compromise NO-mediated responses in IR. We evaluated the role of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA) and arginase with respect to IR-induced impairment of l-arginine/NO-mediated vasodilatation in human morbid obesity and in a non-obese rat model of IR. Bradykinin-induced vasodilatation was evaluated in microarteries derived from insulin-resistant morbidly obese (IR-MO) and non-insulin-resistant MO (NIR-MO) subjects. Defective endothelial vasodilatation in IR-MO was improved by l-arginine supplementation. Increased levels of ADMA were detected in serum and adipose tissue from IR-MO. Serum ADMA positively correlated with IR score and negatively with pD2 for bradykinin. Gene

Exogenous insulin antibody syndrome (EIAS): a clinical syndrome associated with insulin antibodies induced by exogenous insulin in diabetic patients.

Science.gov (United States)

Hu, Xiaolei; Chen, Fengling

2018-01-01

Insulin has been used for diabetes therapy and has achieved significant therapeutic effect. In recent years, the use of purified and recombinant human insulin preparations has markedly reduced, but not completely suppressed, the incidence of insulin antibodies (IAs). IAs induced by exogenous insulin in diabetic patients is associated with clinical events, which is named exogenous insulin antibody syndrome (EIAS). The present review is based on our research and summarizes the characterization of IAs, the factors affecting IA development, the clinical significance of IAs and the treatments for EIAS. © 2018 The authors.

Purified human somatomedin A and rat multiplication stimulating activity

Energy Technology Data Exchange (ETDEWEB)

Rechler, M M; Fryklund, L; Nissley, S P; Hall, K; Podskalny, J M; Skottner, A; Moses, A C [National Institutes of Health, Bethesda, Md. (USA); Kabi AB, Stockholm [Sweden; National Inst. of Arthritis, Metabolism and Digestive Diseases, Bethesda, Md. (USA). Diabetes Branch)

1978-01-01

Specific receptors for MSA and/or somatomedin A could be demonstrated in intact cells or membranes from chick embryo fibroblasts, human fibroblasts, human placenta, rat liver, and the BRL 3A2 cell line, a subclone of the line that produces MSA. Unlabeled MSA and somatomedin A inhibited the binding of /sup 125/I-labeled MSA and /sup 125/I-labeled somatomedin A to each of these receptors with comparable potency. In chick embryo fibroblasts, human fibroblasts, and human placental membranes, the binding of both radioactive ligands also was inhibited by insulin, consistent with the interpretation that /sup 125/I-labeled MSA and /sup 125/I-labeled somatomedin A were binding to the same receptor. By contrast, in the BRL 3A2 cell line, insulin inhibited the binding of /sup 125/I-labeled somatomedin A, but not the binding of /sup 125/I-labeled MSA, suggesting that the two labeled peptides were binding to different receptors in this cell line. Moreover, /sup 125/I-labeled MSA, but not /sup 125/I-labeled somatomedin A, bound specifically to rat liver plasma membranes. These results indicate that human somatomedin A and rat MSA are closely related, but not identical, peptides.

Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans.

Science.gov (United States)

Everman, Sarah; Meyer, Christian; Tran, Lee; Hoffman, Nyssa; Carroll, Chad C; Dedmon, William L; Katsanos, Christos S

2016-10-01

Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA. Copyright © 2016 the American Physiological Society.

A randomized trial of insulin aspart with intensified basal NPH insulin supplementation in people with Type 1 diabetes

NARCIS (Netherlands)

DeVries, J. H.; Lindholm, A.; Jacobsen, J. L.; Heine, R. J.; Home, P. D.

2003-01-01

Aims Insulin aspart has been shown to improve post-prandial and overall glycaemic control in people with Type 1 diabetes. We hypothesized that insulin aspart with intensified basal NPH insulin supplementation would result in better overall glycaemic control than human regular insulin with standard

Effect of insulin catheter wear-time on subcutaneous adipose tissue blood flow and insulin absorption in humans

DEFF Research Database (Denmark)

Clausen, Trine Schnedler; Kaastrup, Peter; Stallknecht, Bente

2009-01-01

blood flow (ATBF) and absorption of the rapid-acting insulin analog insulin aspart over a period of 4 days. METHODS: Teflon insulin catheters (Medtronic, Minneapolis, MN) were inserted into the abdominal SAT of 10 healthy men without diabetes (mean +/- SEM age, 23.0 +/- 1.1 years; body mass index, 22...... +/- 3 min on day 0 to 45 +/- 4 min on day 4 (P = 0.019). Neither peak plasma concentration nor area under the curve of insulin aspart changed significantly. CONCLUSIONS: Insertion of a Teflon insulin catheter into the SAT results in increased ATBF and faster absorption of insulin aspart in a period of 4...

Optimization of codon composition and regulatory elements for expression of human insulin like growth factor-1 in transgenic chloroplasts and evaluation of structural identity and function

Directory of Open Access Journals (Sweden)

Sandberg Laurence

2009-04-01

Full Text Available Abstract Background Transgenic chloroplasts are potential bioreactors for recombinant protein production, especially for achievement of high levels of protein expression and proper folding. Production of therapeutic proteins in leaves provides transgene containment by elimination of reproductive structures. Therefore, in this study, human Insulin like Growth Factor-1 is expressed in transgenic chloroplasts for evaluation of structural identity and function. Results Expression of the synthetic Insulin like Growth Factor 1 gene (IGF-1s, 60% AT was observed in transformed E. coli. However, no native IGF-1 gene (IGF-1n, 41% AT product was detected in the western blots in E. coli. Site-specific integration of the transgenes into the tobacco chloroplast genome was confirmed after transformation using PCR. Southern blot analysis confirmed that the transgenic lines were homoplasmic. The transgenic plant lines had IGF-1s expression levels of 11.3% of total soluble protein (TSP. The IGF-1n plants contained 9.5% TSP as IGF-1n, suggesting that the chloroplast translation machinery is more flexible than E. coli in codon preference and usage. The expression of IGF-1 was increased up to 32% TSP under continuous illumination by the chloroplast light regulatory elements. IgG-Sepharose affinity column chromatographic separation of Z domain containing chloroplast derived IGF-1 protein, single and two dimensional electrophoresis methods and mass spectrometer analysis confirmed the identity of human IGF-1 in transgenic chloroplasts. Two spots analyzed from 2-D focusing/phoresis acrylamide gel showed the correct amino acid sequence of human IGF-1 and the S. aureus Z-tag. Cell proliferation assays in human HU-3 cells demonstrated the biological activity of chloroplast derived IGF-1 even in the presence of the S. aureus Z tag. Conclusion This study demonstrates that the human Insulin like Growth Factor-1 expressed in transgenic chloroplasts is identical to the native

Genetically modified human bone marrow derived mesenchymal stem cells for improving the outcome of human islet transplantation.

Directory of Open Access Journals (Sweden)

Vaibhav Mundra

Full Text Available The objective of this study was to determine the potential of human bone marrow derived mesenchymal stem cells (hBMSCs as gene carriers for improving the outcome of human islet transplantation. hBMSCs were characterized for the expression of phenotypic markers and transduced with Adv-hVEGF-hIL-1Ra to overexpress human vascular endothelial growth factor (hVEGF and human interleukin-1 receptor antagonist (hIL-1Ra. Human islets were co-cultured with hBMSCs overexpressing hVEGF and hIL-1Ra. Islet viability was determined by membrane fluorescent method and glucose stimulation test. Transduced hBMSCs and human islets were co-transplanted under the kidney capsule of NOD.Cg-Prkdc(scid Il2rg(tm1Wjl /SzJ (NSG diabetic mice and blood glucose levels were measured over time to demonstrate the efficacy of genetically modified hBMSCs. At the end of study, immunofluorescent staining of kidney section bearing islets was performed for insulin and von Willebrand Factor (vWF. hBMSCs were positive for the expression of CD73, CD90, CD105, CD146 and Stro-1 surface markers as determined by flow cytometry. Transduction of hBMSCs with adenovirus did not affect their stemness and differentiation potential as confirmed by mRNA levels of stem cell markers and adipogenic differentiation of transduced hBMSCs. hBMSCs were efficiently transduced with Adv-hVEGF-hIL-1Ra to overexpress hVEGF and hIL-1Ra. Live dead cell staining and glucose stimulation test have shown that transduced hBMSCs improved the viability of islets against cytokine cocktail. Co-transplantation of human islets with genetically modified hBMSCs improved the glycemic control of diabetic NSG mice as determined by mean blood glucose levels and intraperitoneal glucose tolerance test. Immunofluorescent staining of kidney sections was positive for human insulin and vWF. In conclusion, our results have demonstrated that hBMSCs may be used as gene carriers and nursing cells to improve the outcome of islet

Insulin analogues in pregnancy and specific congenital anomalies

DEFF Research Database (Denmark)

de Jong, Josta; Garne, Ester; Wender-Ozegowska, Ewa

2016-01-01

Insulin analogues are commonly used in pregnant women with diabetes. It is not known if the use of insulin analogues in pregnancy is associated with any higher risk of congenital anomalies in the offspring compared with use of human insulin. We performed a literature search for studies of pregnant...... women with pregestational diabetes using insulin analogues in the first trimester and information on congenital anomalies. The studies were analysed to compare the congenital anomaly rate among foetuses of mothers using insulin analogues with foetuses of mothers using human insulin. Of 29 studies, we...... samples in the included studies provided insufficient statistical power to identify a moderate increased risk of specific congenital anomalies. Copyright © 2015 John Wiley & Sons, Ltd....

Partial rescue of in vivo insulin signalling in skeletal muscle by impaired insulin clearance in heterozygous carriers of a mutation in the insulin receptor gene

DEFF Research Database (Denmark)

Højlund, K.; Wojtaszewski, Jørgen; Birk, Jesper Bratz

2006-01-01

AIMS/HYPOTHESIS: Recently we reported the coexistence of postprandial hypoglycaemia and moderate insulin resistance in heterozygous carriers of the Arg1174Gln mutation in the insulin receptor gene (INSR). Controlled studies of in vivo insulin signalling in humans with mutant INSR are unavailable,...

Quantitative variation in obesity-related traits and insulin precursors linked to the OB gene region on human chromosome 7

Energy Technology Data Exchange (ETDEWEB)

Duggirala, R.; Stern, M.P.; Reinhart, L.J. [Univ. of Texas Health Science Center, San Antonio, TX (United States)] [and others

1996-09-01

Despite the evidence that human obesity has strong genetic determinants, efforts at identifying specific genes that influence human obesity have largely been unsuccessful. Using the sibship data obtained from 32 low-income Mexican American pedigrees ascertained on a type II diabetic proband and a multipoint variance-components method, we tested for linkage between various obesity-related traits plus associated metabolic traits and 15 markers on human chromosome 7. We found evidence for linkage between markers in the OB gene region and various traits, as follows: D7S514 and extremity skinfolds (LOD = 3.1), human carboxypeptidase A1 (HCPA1) and 32,33-split proinsulin level (LOD = 4.2), and HCPA1 and proinsulin level (LOD = 3.2). A putative susceptibility locus linked to the marker D7S514 explained 56% of the total phenotypic variation in extremity skinfolds. Variation at the HCPA1 locus explained 64% of phenotypic variation in proinsulin level and {approximately}73% of phenotypic variation in split proinsulin concentration, respectively. Weaker evidence for linkage to several other obesity-related traits (e.g., waist circumference, body-mass index, fat mass by bioimpedance, etc.) was observed for a genetic location, which is {approximately}15 cM telomeric to OB. In conclusion, our study reveals that the OB region plays a significant role in determining the phenotypic variation of both insulin precursors and obesity-related traits, at least in Mexican Americans. 66 refs., 3 figs., 4 tabs.

Exogenous insulin antibody syndrome (EIAS: a clinical syndrome associated with insulin antibodies induced by exogenous insulin in diabetic patients

Directory of Open Access Journals (Sweden)

Xiaolei Hu

2018-01-01

Full Text Available Insulin has been used for diabetes therapy and has achieved significant therapeutic effect. In recent years, the use of purified and recombinant human insulin preparations has markedly reduced, but not completely suppressed, the incidence of insulin antibodies (IAs. IAs induced by exogenous insulin in diabetic patients is associated with clinical events, which is named exogenous insulin antibody syndrome (EIAS. The present review is based on our research and summarizes the characterization of IAs, the factors affecting IA development, the clinical significance of IAs and the treatments for EIAS.

Characterization of stimulus-secretion coupling in the human pancreatic EndoC-βH1 beta cell line.

Directory of Open Access Journals (Sweden)

Lotta E Andersson

Full Text Available Studies on beta cell metabolism are often conducted in rodent beta cell lines due to the lack of stable human beta cell lines. Recently, a human cell line, EndoC-βH1, was generated. Here we investigate stimulus-secretion coupling in this cell line, and compare it with that in the rat beta cell line, INS-1 832/13, and human islets.Cells were exposed to glucose and pyruvate. Insulin secretion and content (radioimmunoassay, gene expression (Gene Chip array, metabolite levels (GC/MS, respiration (Seahorse XF24 Extracellular Flux Analyzer, glucose utilization (radiometric, lactate release (enzymatic colorimetric, ATP levels (enzymatic bioluminescence and plasma membrane potential and cytoplasmic Ca2+ responses (microfluorometry were measured. Metabolite levels, respiration and insulin secretion were examined in human islets.Glucose increased insulin release, glucose utilization, raised ATP production and respiratory rates in both lines, and pyruvate increased insulin secretion and respiration. EndoC-βH1 cells exhibited higher insulin secretion, while plasma membrane depolarization was attenuated, and neither glucose nor pyruvate induced oscillations in intracellular calcium concentration or plasma membrane potential. Metabolite profiling revealed that glycolytic and TCA-cycle intermediate levels increased in response to glucose in both cell lines, but responses were weaker in EndoC-βH1 cells, similar to those observed in human islets. Respiration in EndoC-βH1 cells was more similar to that in human islets than in INS-1 832/13 cells.Functions associated with early stimulus-secretion coupling, with the exception of plasma membrane potential and Ca2+ oscillations, were similar in the two cell lines; insulin secretion, respiration and metabolite responses were similar in EndoC-βH1 cells and human islets. While both cell lines are suitable in vitro models, with the caveat of replicating key findings in isolated islets, EndoC-βH1 cells have the

Ibervillea sonorae (Cucurbitaceae) induces the glucose uptake in human adipocytes by activating a PI3K-independent pathway.

Science.gov (United States)

Zapata-Bustos, Rocio; Alonso-Castro, Angel Josabad; Gómez-Sánchez, Maricela; Salazar-Olivo, Luis A

2014-03-28

Ibervillea sonorae (S. Watson) Greene (Cucurbitaceae), a plant used for the empirical treatment of type 2 diabetes in México, exerts antidiabetic effects on animal models but its mechanism of action remains unknown. The aim of this study is to investigate the antidiabetic mechanism of an Ibervillea sonorae aqueous extract (ISE). Non-toxic ISE concentrations were assayed on the glucose uptake by insulin-sensitive and insulin-resistant murine and human cultured adipocytes, both in the absence or the presence of insulin signaling pathway inhibitors, and on murine and human adipogenesis. Chemical composition of ISE was examined by spectrophotometric and HPLC techniques. ISE stimulated the 2-NBDGlucose uptake by mature adipocytes in a concentration-dependent manner. ISE 50 µg/ml induced the 2-NBDG uptake in insulin-sensitive 3T3-F442A, 3T3-L1 and human adipocytes by 100%, 63% and 33%, compared to insulin control. Inhibitors for the insulin receptor, PI3K, AKT and GLUT4 blocked the 2-NBDG uptake in murine cells, but human adipocytes were insensitive to the PI3K inhibitor Wortmannin. ISE 50 µg/ml also stimulated the 2-NBDG uptake in insulin-resistant adipocytes by 117% (3T3-F442A), 83% (3T3-L1) and 48% (human). ISE induced 3T3-F442A adipogenesis but lacked proadipogenic effects on 3T3-L1 and human preadipocytes. Chemical analyses showed the presence of phenolics in ISE, mainly an appreciable concentration of gallic acid. Ibervillea sonorae exerts its antidiabetic properties by means of hydrosoluble compounds stimulating the glucose uptake in human preadipocytes by a PI3K-independent pathway and without proadipogenic effects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

B Lymphocyte Stimulator (BLyS is expressed in human adipocytes in vivo and is related to obesity but not to insulin resistance.

Directory of Open Access Journals (Sweden)

Nike Müller

Full Text Available Inflammation and metabolism have been shown to be evolutionary linked and increasing evidence exists that pro-inflammatory factors are involved in the pathogenesis of obesity and type 2 diabetes. Until now, most data suggest that within adipose tissue these factors are secreted by cells of the innate immune system, e. g. macrophages. In the present study we demonstrate that B lymphocyte stimulator (BLyS is increased in human obesity. In contrast to several pro-inflammatory factors, we found the source of BLyS in human adipose tissue to be the adipocytes rather than immune cells. In grade 3 obese human subjects, expression of BLyS in vivo in adipose tissue is significantly increased (p<0.001. Furthermore, BLyS serum levels are elevated in grade 3 human obesity (862.5+222.0 pg/ml vs. 543.7+60.7 pg/ml in lean controls, p<0.001 and are positively correlated to the BMI (r = 0.43, p<0.0002. In the present study, bariatric surgery significantly altered serum BLyS concentrations. In contrast, weight loss due to a very-low-calorie-formula-diet (800 kcal/d had no such effect. To examine metabolic activity of BLyS, in a translational research approach, insulin sensitivity was measured in human subjects in vivo before and after treatment with the human recombinant anti-BLyS antibody belimumab. Since BLyS is known to promote B-cell proliferation and immunoglobulin secretion, the present data suggest that adipocytes of grade 3 obese human subjects are able to activate the adaptive immune system, suggesting that in metabolic inflammation in humans both, innate and adaptive immunity, are of pathophysiological relevance.

Metformin and insulin receptors

International Nuclear Information System (INIS)

Vigneri, R.; Gullo, D.; Pezzino, V.

1984-01-01

The authors evaluated the effect of metformin (N,N-dimethylbiguanide), a biguanide known to be less toxic than phenformin, on insulin binding to its receptors, both in vitro and in vivo. Specific 125 I-insulin binding to cultured IM-9 human lymphocytes and MCF-7 human breast cancer cells was determined after preincubation with metformin. Specific 125 I-insulin binding to circulating monocytes was also evaluated in six controls, eight obese subjects, and six obese type II diabetic patients before and after a short-term treatment with metformin. Plasma insulin levels and blood glucose were also measured on both occasions. Metformin significantly increased insulin binding in vitro to both IM-9 lymphocytes and MCF-7 cells; the maximum increment was 47.1% and 38.0%, respectively. Metformin treatment significantly increased insulin binding in vivo to monocytes of obese subjects and diabetic patients. Scatchard analysis indicated that the increased binding was mainly due to an increase in receptor capacity. Insulin binding to monocytes of normal controls was unchanged after metformin as were insulin levels in all groups; blood glucose was significantly reduced after metformin only in diabetic patients. These data indicate that metformin increases insulin binding to its receptors in vitro and in vivo. The effect in vivo is observed in obese subjects and in obese type II diabetic patients, paralleling the clinical effectiveness of this antidiabetic agent, and is not due to receptor regulation by circulating insulin, since no variation in insulin levels was recorded

Insulin-like growth factor (IGF)-I binding to a cell membrane associated IGF binding protein-3 acid-labile subunit complex in human anterior pituitary gland

NARCIS (Netherlands)

Wilczak, N; Kuhl, N; Chesik, D; Geerts, A; Luiten, P; De Keyser, J

The binding characteristics of [(125) I]insulin-like growth factor (IGF)-I were studied in human brain and pituitary gland. Competition binding studies with DES(1-3)IGF-I and R-3 -IGF-I, which display high affinity for the IGF-I receptor and low affinity for IGF binding proteins (IGFBPs), were

Novel and Reversible Mechanisms of Smoking-Induced Insulin Resistance in Humans

OpenAIRE

Bergman, Bryan C.; Perreault, Leigh; Hunerdosse, Devon; Kerege, Anna; Playdon, Mary; Samek, Ali M.; Eckel, Robert H.

2012-01-01

Smoking is the most common cause of preventable morbidity and mortality in the United States, in part because it is an independent risk factor for the development of insulin resistance and type 2 diabetes. However, mechanisms responsible for smoking-induced insulin resistance are unclear. In this study, we found smokers were less insulin sensitive compared with controls, which increased after either 1 or 2 weeks of smoking cessation. Improvements in insulin sensitivity after smoking cessation...

Insulin analogues and cancer: a note of caution

Directory of Open Access Journals (Sweden)

Joseph A.M.J.L. eJanssen

2014-05-01

Full Text Available Abstract In view of the lifelong exposure and large patient populations involved, insulin analogues with an increased mitogenic effect in comparison to human insulin may potentially constitute a major health problem, since these analogues may possibly induce the growth of pre-existing neoplasms. At present, the available data suggest that insulin analogues are safe. In line with these findings, we observed that serum of diabetic patients treated with insulin analogues, compared to that of diabetic patients treated with human insulin, did not induce an increased phosphorylation of tyrosine residues of the insulin-like growth factor-I receptor (IGF-IR. However, the classical model of the IGF-IR signaling may be insufficient to explain (all mitogenic effects of insulin analogues since also non-canonical signaling pathways of the IGF-IR may play a major role in this respect. Although phosphorylation of tyrosine residues of the IGF-IR is generally considered to be the initial activation step within the intracellular IGF-IR signaling pathway, it has been found that cells undergo a signaling switch under hyperglycemic conditions. After this switch, a completely different mechanism is utilized to activate the mitogenic (mitogen-activated protein kinase (MAPK pathways of the IGF-IR that is independent from tyrosine phosphorylation of the IGF-IR. At present it is unknown whether activation of this alternative intracellular pathway of the IGF-IR occurs during hyperglycemia in vivo and whether it is stronger in patients treated with (some insulin analogues than in patients treated with human insulin. In addition, it is unknown whether the insulin receptors (IRs also undergo a signaling switch during hyperglycemia. This should be investigated in future studies. Finally, relative overexpression of IR isoform A (IR-A in (pre cancer tissues may play a key role in the development and progression of human cancers during treatment with insulin (analogues. Further

Glucagon-like peptide 1 (GLP-1) suppresses ghrelin levels in humans via increased insulin secretion

DEFF Research Database (Denmark)

Hagemann, Dirk; Holst, Jens Juul; Gethmann, Arnica

2007-01-01

INTRODUCTION: Ghrelin is an orexigenic peptide predominantly secreted by the stomach. Ghrelin plasma levels rise before meal ingestion and sharply decline afterwards, but the mechanisms controlling ghrelin secretion are largely unknown. Since meal ingestion also elicits the secretion...... of the incretin hormone glucagon-like peptide 1 (GLP-1), we examined whether exogenous GLP-1 administration reduces ghrelin secretion in humans. PATIENTS AND METHODS: 14 healthy male volunteers were given intravenous infusions of GLP-1(1.2 pmol x kg(-1) min(-1)) or placebo over 390 min. After 30 min, a solid test...... meal was served. Venous blood was drawn frequently for the determination of glucose, insulin, C-peptide, GLP-1 and ghrelin. RESULTS: During the infusion of exogenous GLP-1 and placebo, GLP-1 plasma concentrations reached steady-state levels of 139+/-15 pmol/l and 12+/-2 pmol/l, respectively (p

Adipose tissue macrophages impair preadipocyte differentiation in humans.

Directory of Open Access Journals (Sweden)

Li Fen Liu

Full Text Available The physiologic mechanisms underlying the relationship between obesity and insulin resistance are not fully understood. Impaired adipocyte differentiation and localized inflammation characterize adipose tissue from obese, insulin-resistant humans. The directionality of this relationship is not known, however. The aim of the current study was to investigate whether adipose tissue inflammation is causally-related to impaired adipocyte differentiation.Abdominal subcutaneous(SAT and visceral(VAT adipose tissue was obtained from 20 human participants undergoing bariatric surgery. Preadipocytes were isolated, and cultured in the presence or absence of CD14+ macrophages obtained from the same adipose tissue sample. Adipocyte differentiation was quantified after 14 days via immunofluorescence, Oil-Red O, and adipogenic gene expression. Cytokine secretion by mature adipocytes cultured with or without CD14+macrophages was quantified.Adipocyte differentiation was significantly lower in VAT than SAT by all measures (p<0.001. With macrophage removal, SAT preadipocyte differentiation increased significantly as measured by immunofluorescence and gene expression, whereas VAT preadipocyte differentiation was unchanged. Adipocyte-secreted proinflammatory cytokines were higher and adiponectin lower in media from VAT vs SAT: macrophage removal reduced inflammatory cytokine and increased adiponectin secretion from both SAT and VAT adipocytes. Differentiation of preadipocytes from SAT but not VAT correlated inversely with systemic insulin resistance.The current results reveal that proinflammatory immune cells in human SAT are causally-related to impaired preadipocyte differentiation, which in turn is associated with systemic insulin resistance. In VAT, preadipocyte differentiation is poor even in the absence of tissue macrophages, pointing to inherent differences in fat storage potential between the two depots.

Eccentric exercise decreases maximal insulin action in humans

DEFF Research Database (Denmark)

Asp, Svend; Daugaard, J R; Kristiansen, S

1996-01-01

subjects participated in two euglycaemic clamps, performed in random order. One clamp was preceded 2 days earlier by one-legged eccentric exercise (post-eccentric exercise clamp (PEC)) and one was without the prior exercise (control clamp (CC)). 2. During PEC the maximal insulin-stimulated glucose uptake...... for all three clamp steps used (P maximal activity of glycogen synthase was identical in the two thighs for all clamp steps. 3. The glucose infusion rate (GIR......) necessary to maintain euglycaemia during maximal insulin stimulation was lower during PEC compared with CC (15.7%, 81.3 +/- 3.2 vs. 96.4 +/- 8.8 mumol kg-1 min-1, P maximal...

Short-term effect of recombinant human growth hormone in patients with alcoholic cirrhosis

DEFF Research Database (Denmark)

Møller, S; Becker, U; Grønbaek, M

1994-01-01

As growth hormone possesses anabolic properties that are active on protein metabolism, and thus of potential benefit to patients with chronic liver disease, we determined the metabolic effects of recombinant human growth hormone on insulin-like growth factor-I (IGF-I) its specific binding proteins......, and liver function. Twenty consecutive patients with cirrhosis were randomized to recombinant human growth hormone (Norditropin, 4 I.U. twice daily) subcutaneously for 6 weeks (n = 10) or conventional medical treatment (n = 10). The serum concentrations of insulin-like growth factor-I in the recombinant...... patients as well as in controls, whereas no change in insulin-like growth factor binding protein-1 concentrations was found. No significant changes were seen in the area under the curve for biochemical liver function tests. We conclude that administration of recombinant human growth hormone induces...

Distinct adiponectin profiles might contribute to differences in susceptibility to type 2 diabetes in dogs and humans.

Science.gov (United States)

Verkest, K R; Rand, J S; Fleeman, L M; Morton, J M; Richards, A A; Rose, F J; Whitehead, J P

2011-08-01

Dogs develop obesity-associated insulin resistance but not type 2 diabetes mellitus. Low adiponectin is associated with progression to type 2 diabetes in obese humans. The aims of this study were to compare total and high molecular weight (HMW) adiponectin and the ratio of HMW to total adiponectin (S(A)) between dogs and humans and to examine whether total or HMW adiponectin or both are associated with insulin resistance in naturally occurring obese dogs. We compared adiponectin profiles between 10 lean dogs and 10 lean humans and between 6 lean dogs and 6 age- and sex-matched, client-owned obese dogs. Total adiponectin was measured with assays validated in each species. We measured S(A) with velocity centrifugation on sucrose gradients. The effect of total and HMW adiponectin concentrations on MINMOD-estimated insulin sensitivity was assessed with linear regression. Lean dogs had total and HMW adiponectin concentrations three to four times higher than lean humans (total: dogs 32 ± 5.6 mg/L, humans 10 ± 1.3 mg/L, Pobese dogs (0.76 ± 0.05 in both groups; P=1). Total adiponectin, HMW adiponectin, and S(A) were not associated with insulin sensitivity in dogs. We propose that differences in adiponectin profiles between humans and dogs might contribute to the propensity of humans but not dogs to develop type 2 diabetes. Dogs with chronic, naturally occurring obesity do not have selectively reduced HMW adiponectin, and adiponectin does not appear to be important in the development of canine obesity-associated insulin resistance. Copyright © 2011 Elsevier Inc. All rights reserved.

Glucagon Decreases IGF-1 Bioactivity in Humans, Independently of Insulin, by Modulating Its Binding Proteins.

Science.gov (United States)

Sarem, Zeinab; Bumke-Vogt, Christiane; Mahmoud, Ayman M; Assefa, Biruhalem; Weickert, Martin O; Adamidou, Aikatarini; Bähr, Volker; Frystyk, Jan; Möhlig, Matthias; Spranger, Joachim; Lieske, Stefanie; Birkenfeld, Andreas L; Pfeiffer, Andreas F H; Arafat, Ayman M

2017-09-01

Depending on its lipolytic activity, glucagon plays a promising role in obesity treatment. Glucagon-induced growth hormone (GH) release can promote its effect on lipid metabolism, although the underlying mechanisms have not been well-defined. The present study highlights the glucagon effect on the GH/insulinlike growth factor 1 (IGF-1)/IGF-binding protein (IGFBP) axis in vivo and in vitro, taking into consideration insulin as a confounding factor. In a double-blind, placebo-controlled study, we investigated changes in GH, IGFBP, and IGF-1 bioactivity after intramuscular glucagon administration in 13 lean controls, 11 obese participants, and 13 patients with type 1 diabetes mellitus (T1DM). The effect of glucagon on the transcription factor forkhead box protein O1 (FOXO1) translocation, the transcription of GH/IGF-1 system members, and phosphorylation of protein kinase B (Akt) was further investigated in vitro. Despite unchanged total IGF-1 and IGFBP-3 levels, glucagon decreased IGF-1 bioactivity in all study groups by increasing IGFBP-1 and IGFBP-2. The reduction in IGF-1 bioactivity occurred before the glucagon-induced surge in GH. In contrast to the transient increase in circulating insulin in obese and lean participants, no change was observed in those with T1DM. In vitro, glucagon dose dependently induced a substantial nuclear translocation of FOXO1 in human osteosarcoma cells and tended to increase IGFBP-1 and IGFBP-2 gene expression in mouse primary hepatocytes, despite absent Akt phosphorylation. Our data point to the glucagon-induced decrease in bioactive IGF-1 levels as a mechanism through which glucagon induces GH secretion. This insulin-independent reduction is related to increased IGFBP-1 and IGFBP-2 levels, which are most likely mediated via activation of the FOXO/mTOR (mechanistic target of rapamycin) pathway. Copyright © 2017 Endocrine Society

Activation of peroxisome proliferator-activated receptor-α enhances fatty acid oxidation in human adipocytes

International Nuclear Information System (INIS)

Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki; Kawada, Teruo

2011-01-01

Highlights: → PPARα activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. → PPARα activation also increased insulin-dependent glucose uptake in human adipocytes. → PPARα activation did not affect lipid accumulation in human adipocytes. → PPARα activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-α (PPARα) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPARα in adipocytes have been unclarified. We examined the functions of PPARα using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPARα by GW7647, a potent PPARα agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPARγ, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPARα activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPARγ is activated. On the other hand, PPARα activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPARα-dependent manner. Moreover, PPARα activation increased the production of CO 2 and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPARα stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPARα agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected effects of PPARα activation are very valuable for managing diabetic conditions accompanied by obesity, because

In nondiabetic, human immunodeficiency virus-infected patients with lipodystrophy, hepatic insulin extraction and posthepatic insulin clearance rate are decreased in proportion to insulin resistance

DEFF Research Database (Denmark)

Haugaard, Steen B; Andersen, Ove; Hansen, Birgitte R

2005-01-01

In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic...... endogenous insulin secretion, which was estimated by deconvolution of C-peptide concentrations. Hepatic extraction of insulin was calculated as 1 minus the ratio of fasting posthepatic insulin delivery rate to fasting endogenous insulin secretion rate. Compared with controls, LIPO displayed increased fasting...... insulin (130%, P Hepatic extraction of insulin was similar between groups (LIPO, 55%; controls, 57%; P > .8). In LIPO, HEXi and MCRi correlated inversely with fasting insulin (r = -0.56, P

Design of insulin analogues for meal-related therapy.

Science.gov (United States)

Brange, J

1993-01-01

The human insulin in replacement therapy has a hexameric structure. Hexamerization of the insulin molecule facilitates biosynthesis and beta-cell storage of insulin, but is unnecessary for biologic activity and appears to contribute to delayed absorption of exogenous insulin from the subcutis. Insulin analogues with reduced self-association that are produced through recombinant DNA techniques have been shown to have in vivo activity comparable to that of human insulin and absorption kinetics characterized by higher and more constant rates of disappearance from the subcutaneous injection site. In preliminary studies in patients receiving insulin therapy, monomeric insulin analogues have been found to provide glycemic control in the postprandial period that is at least equivalent to that of human insulin. Findings in these studies suggest that the use of such analogues may provide meal-related insulin effects closer to those observed in the physiologic state by limiting excessive postprandial glucose excursions and decreasing the risk of late hypoglycemia. Banting and Best revolutionized diabetes therapy 70 years ago with the extraction of insulin from animal pancreas glands (J Lab Clin Med 7:464-472, 1922). Since that time, many refinements of the therapeutic properties of pharmaceutical preparations of the hormone have been introduced. Until recently, however, such advances have been limited to improvements in insulin purity, insulin species, and adjustment of the composition of the vehicle with respect to auxiliary substances and other additives. With the advent of recombinant DNA techniques, it has become possible to optimize the insulin molecule itself for purposes of replacement therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin-induced inhibition of gluconeogenesis genes, including glutamic pyruvic transaminase 2, is associated with reduced histone acetylation in a human liver cell line.

Science.gov (United States)

Honma, Kazue; Kamikubo, Michiko; Mochizuki, Kazuki; Goda, Toshinao

2017-06-01

Hepatic glutamic pyruvic transaminase (GPT; also known as alanine aminotransferase) is a gluconeogenesis enzyme that catalyzes conversions between alanine and pyruvic acid. It is also used as a blood biomarker for hepatic damage. In this study, we investigated whether insulin regulates GPT expression, as it does for other gluconeogenesis genes, and if this involves the epigenetic modification of histone acetylation. Human liver-derived HepG2 cells were cultured with 0.5-100nM insulin for 8h, and the mRNA expression of GPT, glutamic-oxaloacetic transaminase (GOT), γ-glutamyltransferase (GGT), PCK1, G6PC and FBP1 was measured. We also investigated the extent of histone acetylation around these genes. Insulin suppressed the mRNA expression of gluconeogenesis genes (GPT2, GOT1, GOT2, GGT1, GGT2, G6PC, and PCK1) in HepG2 cells in a dose-dependent manner. mRNA levels of GPT2, but not GPT1, were decreased by insulin. Histone acetylation was also reduced around GPT2, G6PC, and PCK1 in response to insulin. The expression of GPT2 and other gluconeogenesis genes such as G6PC and PCK1 was suppressed by insulin, in association with decreases in histone H3 and H4 acetylation surrounding these genes. Copyright © 2017 Elsevier Inc. All rights reserved.

Application of simple fed-batch technique to high-level secretory production of insulin precursor using Pichia pastoris with subsequent purification and conversion to human insulin

Directory of Open Access Journals (Sweden)

Chugh Dipti

2010-05-01

Full Text Available Abstract Background The prevalence of diabetes is predicted to rise significantly in the coming decades. A recent analysis projects that by the year 2030 there will be ~366 million diabetics around the world, leading to an increased demand for inexpensive insulin to make this life-saving drug also affordable for resource poor countries. Results A synthetic insulin precursor (IP-encoding gene, codon-optimized for expression in P. pastoris, was cloned in frame with the Saccharomyces cerevisiae α-factor secretory signal and integrated into the genome of P. pastoris strain X-33. The strain was grown to high-cell density in a batch procedure using a defined medium with low salt and high glycerol concentrations. Following batch growth, production of IP was carried out at methanol concentrations of 2 g L-1, which were kept constant throughout the remaining production phase. This robust feeding strategy led to the secretion of ~3 gram IP per liter of culture broth (corresponding to almost 4 gram IP per liter of cell-free culture supernatant. Using immobilized metal ion affinity chromatography (IMAC as a novel approach for IP purification, 95% of the secreted product was recovered with a purity of 96% from the clarified culture supernatant. Finally, the purified IP was trypsin digested, transpeptidated, deprotected and further purified leading to ~1.5 g of 99% pure recombinant human insulin per liter of culture broth. Conclusions A simple two-phase cultivation process composed of a glycerol batch and a constant methanol fed-batch phase recently developed for the intracellular production of the Hepatitis B surface antigen was adapted to secretory IP production. Compared to the highest previously reported value, this approach resulted in an ~2 fold enhancement of IP production using Pichia based expression systems, thus significantly increasing the efficiency of insulin manufacture.

UV-light exposure of insulin: pharmaceutical implications upon covalent insulin dityrosine dimerization and disulphide bond photolysis.

Science.gov (United States)

Correia, Manuel; Neves-Petersen, Maria Teresa; Jeppesen, Per Bendix; Gregersen, Søren; Petersen, Steffen B

2012-01-01

In this work we report the effects of continuous UV-light (276 nm, ~2.20 W.m(-2)) excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin's structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes in protein

UV-light exposure of insulin: pharmaceutical implications upon covalent insulin dityrosine dimerization and disulphide bond photolysis.

Directory of Open Access Journals (Sweden)

Manuel Correia

Full Text Available In this work we report the effects of continuous UV-light (276 nm, ~2.20 W.m(-2 excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin's structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes

Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

NARCIS (Netherlands)

Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

Hypoglycemia in type 1 diabetic pregnancy: role of preconception insulin aspart treatment in a randomized study

DEFF Research Database (Denmark)

Heller, Simon; Damm, Peter; Mersebach, Henriette

2010-01-01

OBJECTIVE A recent randomized trial compared prandial insulin aspart (IAsp) with human insulin in type 1 diabetic pregnancy. The aim of this exploratory analysis was to investigate the incidence of severe hypoglycemia during pregnancy and compare women enrolled preconception with women enrolled...... during early pregnancy. RESEARCH DESIGN AND METHODS IAsp administered immediately before each meal was compared with human insulin administered 30 min before each meal in 99 subjects (44 to IAsp and 55 to human insulin) randomly assigned preconception and in 223 subjects (113 for IAsp and 110 for human...... insulin) randomly assigned in early pregnancy (...

Spectrum of lipid and lipoprotein indices in human subjects with insulin resistance syndrome

International Nuclear Information System (INIS)

Khan, S.H.; Khan, F.A.; Mohammad, A.S.

2008-01-01

Insulin resistance syndrome or metabolic syndrome is one of the major metabolic threats our recently urbanized society is going to face in near future. The management of this syndrome requires a very effective biochemical marker for screening. The objective of this cross sectional study were to compare various lipid and lipoprotein indices in human subjects with insulin resistance syndrome This study was carried out between April 2004 to January 2006 at the department of chemical pathology and endocrinology, Armed Forces Institute of Pathology, Rawalpindi. A total of forty-seven subjects with metabolic syndrome were selected as per the criteria of National Cholesterol Education Program, Adult Treatment Panel III (NCEP, ATP III) from a target population diagnosed to have impaired glucose regulation at AFIP. Forty-seven age and sex-matched healthy controls were also included in the study. Insulin resistance was calculated by the method of HOMA-IR, using the formula of Mathew's et al. The various lipid and lipoproteins, their ratios and log-transformed versions were evaluated for differences between subjects with metabolic syndrome and controls. Finally the diagnostic performances of these candidate lipid markers were evaluated. Results between subjects with metabolic syndrome and controls were found to be significant for serum triglyceride (p<0.05), HDL-C (p<0.05), triglyceride/HDLC (p<0.01), Log triglyceride/HDL-C (p<0.01), total cholesterol/HDL-C (p<0.01), LDL-C/HDL-C (p<0.01). However there was weak correlation between these lipid based markers and HOMA-IR ((serum triglyceride: r= 0.225), (HDL-C: r= -0.235), (triglyceride/HDL-C: r= 0.333), (total cholesterol/HDL-C: r= 0.239)). The AUCs for the diagnosis of metabolic syndrome remained highest for HOMA-IR (0.727 (95%CI: 0.642-0.812)), followed by triglyceride/HDL-C (0.669 (95%CI: 0.572-0.766)) and LDLC/ HDL-C (0.639 (95%CI: 0.537-0.742)). The differences for lipids and lipoproteins between subjects with metabolic

Sequence of a New World primate insulin having low biological potency and immunoreactivity

Energy Technology Data Exchange (ETDEWEB)

Seino, S.; Steiner, D.F.; Bell, G.I.

1987-11-01

The organization of the insulin gene of the owl or night monkey (Aotus trivirgatus), a New World primate, is similar to that of the human gene. The sequences of these two genes and flanking regions possess 84.3% homology. An unusual feature of the owl monkey gene is the partial duplication and insertion of a portion of the A-chain coding sequence into the 3' untranslated region. The insulin gene of this primate also lacks a region of tandem repeats that is present in the 5' flanking region of the human and chimpanzee genes. Owl monkey preproinsulin has 85.5% identity with the human insulin precursor and is the most divergent of the primate insulins/preproinsulins yet described. The differences between owl monkey and human preproinsulin include three substitutions in the signal peptide, two in the B chain, seven in the C peptide, and three in the A chain. One of these replacements is the conservative substitution of valine for isoleucine a position A2, an invariant site in all other vertebrate insulins and insulin-like growth factors. The substitutions in owl monkey insulin at B9, B27, A2, A4, and A17 alter its structure so that it has only 20% of the receptor-binding activity and 1% of the affinity with guinea pig anti-porcine insulin antibodies as compared to human insulin.

Sequence of a New World primate insulin having low biological potency and immunoreactivity

International Nuclear Information System (INIS)

Seino, S.; Steiner, D.F.; Bell, G.I.

1987-01-01

The organization of the insulin gene of the owl or night monkey (Aotus trivirgatus), a New World primate, is similar to that of the human gene. The sequences of these two genes and flanking regions possess 84.3% homology. An unusual feature of the owl monkey gene is the partial duplication and insertion of a portion of the A-chain coding sequence into the 3' untranslated region. The insulin gene of this primate also lacks a region of tandem repeats that is present in the 5' flanking region of the human and chimpanzee genes. Owl monkey preproinsulin has 85.5% identity with the human insulin precursor and is the most divergent of the primate insulins/preproinsulins yet described. The differences between owl monkey and human preproinsulin include three substitutions in the signal peptide, two in the B chain, seven in the C peptide, and three in the A chain. One of these replacements is the conservative substitution of valine for isoleucine a position A2, an invariant site in all other vertebrate insulins and insulin-like growth factors. The substitutions in owl monkey insulin at B9, B27, A2, A4, and A17 alter its structure so that it has only 20% of the receptor-binding activity and 1% of the affinity with guinea pig anti-porcine insulin antibodies as compared to human insulin

[Targeting the brain through the nose. Effects of intranasally administered insulin].

Science.gov (United States)

Brünner, Y F; Benedict, C; Freiherr, J

2013-08-01

The assumption that the human brain is an insulin-independent organ was disproved with the discovery of insulin receptors in the central nervous system in the year 1978. Evidence has been provided for a high density of insulin receptors in brain regions responsible for cognitive memory processes (hippocampus) and for the regulation of appetite (hypothalamus). Accordingly, in animal studies an increased insulin level in the central nervous system leads to an improvement of hippocampal memory function and a decrease of food intake. Similar results were obtained in humans using the method of intranasal administration of insulin. Intranasal insulin reaches the brain and the cerebrospinal fluid via the olfactory epithelium and olfactory nerve fiber bundles leading through the lamina cribrosa to the olfactory bulb. Thus, this method renders the investigation of specific insulin effects in humans possible. The therapeutic potential of an intranasal insulin administration for the treatment of diseases for which an imbalance of the central nervous insulin metabolism is discussed (e.g. Alzheimer's disease, diabetes mellitus and obesity) can only be estimated with the help of further clinical studies.

In nondiabetic, human immunodeficiency virus-infected patients with lipodystrophy, hepatic insulin extraction and posthepatic insulin clearance rate are decreased in proportion to insulin resistance

DEFF Research Database (Denmark)

Haugaard, Steen B; Andersen, Ove; Hansen, Birgitte R

2005-01-01

In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic...... > .1). Our data suggest that HEXi and MCRi are decreased in proportion to the degree of insulin resistance in nondiabetic HIV-infected patients with lipodystrophy....... insulin clearance rate was estimated as the ratio of posthepatic insulin appearance rate to steady-state plasma insulin concentration during a euglycemic hyperinsulinemic clamp (40 mU.m-2 .min-1). Posthepatic insulin appearance rate during the clamp was calculated, taking into account the remnant...

Thermo-responsive human α-elastin self-assembled nanoparticles for protein delivery.

Science.gov (United States)

Kim, Jae Dong; Jung, Youn Jae; Woo, Chang Hee; Choi, Young Chan; Choi, Ji Suk; Cho, Yong Woo

2017-01-01

Self-assembled nanoparticles based on PEGylated human α-elastin were prepared as a potential vehicle for sustained protein delivery. The α-elastin was extracted from human adipose tissue and modified with methoxypolyethyleneglycol (mPEG) to control particle size and enhance the colloidal stability. The PEGylated human α-elastin showed sol-to-particle transition with a lower critical solution temperature (LCST) of 25°C-40°C in aqueous media. The PEGylated human α-elastin nanoparticles (PhENPs) showed a narrow size distribution with an average diameter of 330±33nm and were able to encapsulate significant amounts of insulin and bovine serum albumin (BSA) upon simple mixing at low temperature in water and subsequent heating to physiological temperature. The release profiles of insulin and BSA showed sustained release for 72h. Overall, the thermo-responsive self-assembled PhENPs provide a useful tool for a range of protein delivery and tissue engineering applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Cloning of a human insulin-stimulated protein kinase (ISPK-1) gene and analysis of coding regions and mRNA levels of the ISPK-1 and the protein phosphatase-1 genes in muscle from NIDDM patients

DEFF Research Database (Denmark)

Bjørbaek, C; Vik, T A; Echwald, S M

1995-01-01

with non-insulin-dependent diabetes mellitus (NIDDM). The human ISPK-1 cDNA was cloned from T-cell leukemia and placental cDNA libraries and mapped to the short arm of the human X chromosome. Single-strand conformation polymorphism (SSCP) analysis identified a total of six variations in the coding regions...

Differentiation of human multipotent dermal fibroblasts into islet-like cell clusters

Directory of Open Access Journals (Sweden)

Liu Wei

2010-06-01

Full Text Available Abstract Background We have previously obtained a clonal population of cells from human foreskin that is able to differentiate into mesodermal, ectodermal and endodermal progenies. It is of great interest to know whether these cells could be further differentiated into functional insulin-producing cells. Results Sixty-one single-cell-derived dermal fibroblast clones were established from human foreskin by limiting dilution culture. Of these, two clones could be differentiated into neuron-, adipocyte- or hepatocyte-like cells under certain culture conditions. In addition, those two clones were able to differentiate into islet-like clusters under pancreatic induction. Insulin, glucagon and somatostatin were detectable at the mRNA and protein levels after induction. Moreover, the islet-like clusters could release insulin in response to glucose in vitro. Conclusions This is the first study to demonstrate that dermal fibroblasts can differentiate into insulin-producing cells without genetic manipulation. This may offer a safer cell source for future stem cell-based therapies.

Insulin and leptin induce Glut4 plasma membrane translocation and glucose uptake in a human neuronal cell line by a phosphatidylinositol 3-kinase- dependent mechanism.

Science.gov (United States)

Benomar, Yacir; Naour, Nadia; Aubourg, Alain; Bailleux, Virginie; Gertler, Arieh; Djiane, Jean; Guerre-Millo, Michèle; Taouis, Mohammed

2006-05-01

The insulin-sensitive glucose transporter Glut4 is expressed in brain areas that regulate energy homeostasis and body adiposity. In contrast with peripheral tissues, however, the impact of insulin on Glut4 plasma membrane (PM) translocation in neurons is not known. In this study, we examined the role of two anorexic hormones (leptin and insulin) on Glut4 translocation in a human neuronal cell line that express endogenous insulin and leptin receptors. We show that insulin and leptin both induce Glut4 translocation to the PM of neuronal cells and activate glucose uptake. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase, totally abolished insulin- and leptin-dependent Glut4 translocation and stimulation of glucose uptake. Thus, Glut4 translocation is a phosphatidylinositol 3-kinase-dependent mechanism in neuronal cells. Next, we investigated the impact of chronic insulin and leptin treatments on Glut4 expression and translocation. Chronic exposure of neuronal cells to insulin or leptin down-regulates Glut4 proteins and mRNA levels and abolishes the acute stimulation of glucose uptake in response to acute insulin or leptin. In addition, chronic treatment with either insulin or leptin impaired Glut4 translocation. A cross-desensitization between insulin and leptin was apparent, where exposure to insulin affects leptin-dependent Glut4 translocation and vice versa. This cross-desensitization could be attributed to the increase in suppressor of cytokine signaling-3 expression, which was demonstrated in response to each hormone. These results provide evidence to suggest that Glut4 translocation to neuronal PM is regulated by both insulin and leptin signaling pathways. These pathways might contribute to an in vivo glucoregulatory reflex involving a neuronal network and to the anorectic effect of insulin and leptin.

Comparative Aspects of Human, Canine, and Feline Obesity and Factors Predicting Progression to Diabetes

Directory of Open Access Journals (Sweden)

Margarethe Hoenig

2014-08-01

Full Text Available Obesity and diabetes mellitus are common diseases in humans, dogs and cats and their prevalence is increasing. Obesity has been clearly identified as a risk factor for type 2 diabetes in humans and cats but recent data are missing in dogs, although there is evidence that the unprecedented rise in canine obesity in the last decade has led to a rise in canine diabetes of similar magnitude. The insulin resistance of obesity has often been portrayed as major culprit in the loss of glucose control; however, insulin resistance alone is not a good indicator of progression to diabetes in people or pets. A loss of beta cell function is necessary to provide the link to impaired fasting and post-prandial plasma glucose. Increased endogenous glucose output by the liver is also a prerequisite for the increase in fasting blood glucose when non-diabetic obese humans and pets develop diabetes. This may be due to decreased hepatic insulin sensitivity, decreased insulin concentrations, or a combination of both. While inflammation is a major link between obesity and diabetes in humans, there is little evidence that a similar phenomenon exists in cats. In dogs, more studies are needed to examine this important issue.

Human Monoclonal Islet Cell Antibodies From a Patient with Insulin- Dependent Diabetes Mellitus Reveal Glutamate Decarboxylase as the Target Antigen

Science.gov (United States)

Richter, Wiltrud; Endl, Josef; Eiermann, Thomas H.; Brandt, Michael; Kientsch-Engel, Rosemarie; Thivolet, Charles; Jungfer, Herbert; Scherbaum, Werner A.

1992-09-01

The autoimmune phenomena associated with destruction of the β cell in pancreatic islets and development of type 1 (insulin-dependent) diabetes mellitus (IDDM) include circulating islet cell antibodies. We have immortalized peripheral blood lymphocytes from prediabetic individuals and patients with newly diagnosed IDDM by Epstein-Barr virus transformation. IgG-positive cells were selected by anti-human IgG-coupled magnetic beads and expanded in cell culture. Supernatants were screened for cytoplasmic islet cell antibodies using the conventional indirect immunofluorescence test on cryostat sections of human pancreas. Six islet cell-specific B-cell lines, originating from a patient with newly diagnosed IDDM, could be stabilized on a monoclonal level. All six monoclonal islet cell antibodies (MICA 1-6) were of the IgG class. None of the MICA reacted with human thyroid, adrenal gland, anterior pituitary, liver, lung, stomach, and intestine tissues but all six reacted with pancreatic islets of different mammalian species and, in addition, with neurons of rat cerebellar cortex. MICA 1-6 were shown to recognize four distinct antigenic epitopes in islets. Islet cell antibody-positive diabetic sera but not normal human sera blocked the binding of the monoclonal antibodies to their target epitopes. Immunoprecipitation of 35S-labeled human islet cell extracts revealed that a protein of identical size to the enzyme glutamate decarboxylase (EC 4.1.1.15) was a target of all MICA. Furthermore, antigen immunotrapped by the MICA from brain homogenates showed glutamate decarboxylase enzyme activity. MICA 1-6 therefore reveal glutamate decarboxylase as the predominant target antigen of cytoplasmic islet cell autoantibodies in a patient with newly diagnosed IDDM.

Regulation of lipoprotein lipase in primary cultures of isolated human adipocytes

International Nuclear Information System (INIS)

Kern, P.A.; Marshall, S.; Eckel, R.H.

1985-01-01

To study the regulation of adipose tissue lipoprotein lipase (LPL) in human adipocytes, omental adipose tissue was obtained from healthy subjects and digested in collagenase. The isolated adipocytes thus obtained were suspended in Medium 199 and cultured at 37 degrees C. Cell viability was demonstrated in adipocytes cultured for up to 72 h by constancy of cell number, cell size, trypan-blue exclusion, and specific 125 I-insulin binding. In addition, chloroquine induced an increase in cell-associated 125 I-insulin at 24, 48, and 72 h after preparation. Thus, isolated adipocytes retained their ability to bind, internalize, and degrade insulin. LPL was measured as activity secreted into the culture medium (CM), released from cells by heparin (HR), and extracted from cell digests. A broad range of heparin concentrations produced a prompt release of LPL from a rapidly replenishable pool of cellular activity. When cells were cultured in medium containing 10% fetal bovine serum, there was a marked stimulation of CM and HR. The secretory response to serum (CM) correlated strongly with HR 24 h after preparation. In addition, HR was found to correlate logarithmically and inversely with body mass index. Insulin, at 400 ng/ml only, increased HR by 36 +/- 10%, an effect simulated by lower concentrations of insulin-like growth factor-1 (IGF1). Thus, LPL is produced and regulated in isolated human adipocytes. The degree of adiposity and serum are important regulators of HR activity, whereas insulin is stimulatory only at a pharmacologic concentration. This effect of insulin may be mediated through the IGF1 receptor. Isolated human adipocytes represent a novel and useful system for the study of LPL and lipid metabolism as well as for other aspects of adipocyte biology

Effects of exogenous human insulin dose adjustment on body mass ...

African Journals Online (AJOL)

glycaemic control by frequent exogenous insulin injections. To maintain fasting ... mass index in adult patients with type 1 diabetes mellitus at Kalafong Hospital ..... The Diabetes Control and Complications Trial cited in the review by Kaufman[2] also .... in obese insulin-resistant children: A randomized clinical trial. Diabetes ...

DigitalHuman (DH): An Integrative Mathematical Model ofHuman Physiology

Science.gov (United States)

Hester, Robert L.; Summers, Richard L.; lIescu, Radu; Esters, Joyee; Coleman, Thomas G.

2010-01-01

Mathematical models and simulation are important tools in discovering the key causal relationships governing physiological processes and improving medical intervention when physiological complexity is a central issue. We have developed a model of integrative human physiology called DigitalHuman (DH) consisting of -5000 variables modeling human physiology describing cardiovascular, renal, respiratory, endocrine, neural and metabolic physiology. Users can view time-dependent solutions and interactively introduce perturbations by altering numerical parameters to investigate new hypotheses. The variables, parameters and quantitative relationships as well as all other model details are described in XML text files. All aspects of the model, including the mathematical equations describing the physiological processes are written in XML open source, text-readable files. Model structure is based upon empirical data of physiological responses documented within the peer-reviewed literature. The model can be used to understand proposed physiological mechanisms and physiological interactions that may not be otherwise intUitively evident. Some of the current uses of this model include the analyses of renal control of blood pressure, the central role of the liver in creating and maintaining insulin resistance, and the mechanisms causing orthostatic hypotension in astronauts. Additionally the open source aspect of the modeling environment allows any investigator to add detailed descriptions of human physiology to test new concepts. The model accurately predicts both qualitative and more importantly quantitative changes in clinically and experimentally observed responses. DigitalHuman provides scientists a modeling environment to understand the complex interactions of integrative physiology. This research was supported by.NIH HL 51971, NSF EPSCoR, and NASA

Hypoglycemia in type 1 diabetic pregnancy: role of preconception insulin aspart treatment in a randomized study

DEFF Research Database (Denmark)

Heller, Simon; Damm, Peter; Mersebach, Henriette

2010-01-01

OBJECTIVE A recent randomized trial compared prandial insulin aspart (IAsp) with human insulin in type 1 diabetic pregnancy. The aim of this exploratory analysis was to investigate the incidence of severe hypoglycemia during pregnancy and compare women enrolled preconception with women enrolled...... during early pregnancy. RESEARCH DESIGN AND METHODS IAsp administered immediately before each meal was compared with human insulin administered 30 min before each meal in 99 subjects (44 to IAsp and 55 to human insulin) randomly assigned preconception and in 223 subjects (113 for IAsp and 110 for human...

Data in support of FSH induction of IRS-2 in human granulosa cells: Mapping the transcription factor binding sites in human IRS-2 promoter

Directory of Open Access Journals (Sweden)

Surleen Kaur

2016-03-01

Full Text Available Insulin receptor substrate-2 (IRS-2 plays critical role in the regulation of various metabolic processes by insulin and IGF-1. The defects in its expression and/or function are linked to diseases like polycystic ovary syndrome (PCOS, insulin resistance and cancer. To predict the transcription factors (TFs responsible for the regulation of human IRS-2 gene expression, the transcription factor binding sites (TFBS and the corresponding TFs were investigated by analysis of IRS-2 promoter sequence using MatInspector Genomatix software (Cartharius et al., 2005 [1]. The ibid data is part of author׳s publication (Anjali et al., 2015 [2] that explains Follicle stimulating hormone (FSH mediated IRS-2 promoter activation in human granulosa cells and its importance in the pathophysiology of PCOS. Further analysis was carried out for binary interactions of TF regulatory genes in IRS-2 network using Cytoscape software tool and R-code. In this manuscript, we describe the methodology used for the identification of TFBSs in human IRS-2 promoter region and provide details on experimental procedures, analysis method, validation of data and also the raw files. The purpose of this article is to provide the data on all TFBSs in the promoter region of human IRS-2 gene as it has the potential for prediction of the regulation of IRS-2 gene in normal or diseased cells from patients with metabolic disorders and cancer. Keywords: IRS-2, TFBS, FSH, SP1, ChIP

The Generation of Insulin Producing Cells from Human Mesenchymal Stem Cells by MiR-375 and Anti-MiR-9.

Science.gov (United States)

Jafarian, Arefeh; Taghikani, Mohammad; Abroun, Saeid; Allahverdi, Amir; Lamei, Maryam; Lakpour, Niknam; Soleimani, Masoud

2015-01-01

MicroRNAs (miRNAs) are a group of endogenous small non-coding RNAs that regulate gene expression at the post-transcriptional level. A number of studies have led to the notion that some miRNAs have key roles in control of pancreatic islet development and insulin secretion. Based on some studies on miRNAs pattern, the researchers in this paper investigated the pancreatic differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) by up-regulation of miR-375 and down-regulation of miR-9 by lentiviruses containing miR-375 and anti-miR-9. After 21 days of induction, islet-like clusters containing insulin producing cells (IPCs) were confirmed by dithizone (DTZ) staining. The IPCs and β cell specific related genes and proteins were detected using qRT-PCR and immunofluorescence on days 7, 14 and 21 of differentiation. Glucose challenge test was performed at different concentrations of glucose so extracellular and intracellular insulin and C-peptide were assayed using ELISA kit. Although derived IPCs by miR-375 alone were capable to express insulin and other endocrine specific transcription factors, the cells lacked the machinery to respond to glucose. It was found that over-expression of miR-375 led to a reduction in levels of Mtpn protein in derived IPCs, while treatment with anti-miR-9 following miR-375 over-expression had synergistic effects on MSCs differentiation and insulin secretion in a glucose-regulated manner. The researchers reported that silencing of miR-9 increased OC-2 protein in IPCs that may contribute to the observed glucose-regulated insulin secretion. Although the roles of miR-375 and miR-9 are well known in pancreatic development and insulin secretion, the use of these miRNAs in transdifferentiation was never demonstrated. These findings highlight miRNAs functions in stem cells differentiation and suggest that they could be used as therapeutic tools for gene-based therapy in diabetes mellitus.

Challenges constraining access to insulin in the private-sector market of Delhi, India.

Science.gov (United States)

Sharma, Abhishek; Kaplan, Warren A

2016-01-01

India's majority of patients-including those living with diabetes-seek healthcare in the private sector through out-of-pocket (OOP) payments. We studied access to insulin in the private-sector market of Delhi state, India. A modified World Health Organization/Health Action International (WHO/HAI) standard survey to assess insulin availability and prices, and qualitative interviews with insulin retailers (pharmacists) and wholesalers to understand insulin market dynamics. In 40 pharmacy outlets analysed, mean availability of the human and analogue insulins on the 2013 Delhi essential medicine list was 44.4% and 13.1%, respectively. 82% of pharmacies had domestically manufactured human insulin phials, primarily was made in India under licence to overseas pharmaceutical companies. Analogue insulin was only in cartridge and pen forms that were 4.42 and 5.81 times, respectively, the price of human insulin phials. Domestically manufactured human phial and cartridge insulin (produced for foreign and Indian companies) was less expensive than their imported counterparts. The lowest paid unskilled government worker in Delhi would work about 1.5 and 8.6 days, respectively, to be able to pay OOP for a monthly supply of human phial and analogue cartridge insulin. Interviews suggest that the Delhi insulin market is dominated by a few multinational companies that import and/or license in-country production. Several factors influence insulin uptake by patients, including doctor's prescribing preference. Wholesalers have negative perceptions about domestic insulin manufacturing. The Delhi insulin market is an oligopoly with limited market competition. Increasing competition from Indian companies is going to require some additional policies, not presently in place. As more Indian companies produce biosimilars, brand substitution policies are needed to be able to benefit from market competition.

Challenges constraining access to insulin in the private-sector market of Delhi, India

Science.gov (United States)

Kaplan, Warren A

2016-01-01

Objective India's majority of patients—including those living with diabetes—seek healthcare in the private sector through out-of-pocket (OOP) payments. We studied access to insulin in the private-sector market of Delhi state, India. Methods A modified World Health Organization/Health Action International (WHO/HAI) standard survey to assess insulin availability and prices, and qualitative interviews with insulin retailers (pharmacists) and wholesalers to understand insulin market dynamics. Results In 40 pharmacy outlets analysed, mean availability of the human and analogue insulins on the 2013 Delhi essential medicine list was 44.4% and 13.1%, respectively. 82% of pharmacies had domestically manufactured human insulin phials, primarily was made in India under licence to overseas pharmaceutical companies. Analogue insulin was only in cartridge and pen forms that were 4.42 and 5.81 times, respectively, the price of human insulin phials. Domestically manufactured human phial and cartridge insulin (produced for foreign and Indian companies) was less expensive than their imported counterparts. The lowest paid unskilled government worker in Delhi would work about 1.5 and 8.6 days, respectively, to be able to pay OOP for a monthly supply of human phial and analogue cartridge insulin. Interviews suggest that the Delhi insulin market is dominated by a few multinational companies that import and/or license in-country production. Several factors influence insulin uptake by patients, including doctor's prescribing preference. Wholesalers have negative perceptions about domestic insulin manufacturing. Conclusions The Delhi insulin market is an oligopoly with limited market competition. Increasing competition from Indian companies is going to require some additional policies, not presently in place. As more Indian companies produce biosimilars, brand substitution policies are needed to be able to benefit from market competition. PMID:28588966

Expansion of Adult Human Pancreatic Tissue Yields Organoids Harboring Progenitor Cells with Endocrine Differentiation Potential

Directory of Open Access Journals (Sweden)

Cindy J.M. Loomans

2018-03-01

Full Text Available Summary: Generating an unlimited source of human insulin-producing cells is a prerequisite to advance β cell replacement therapy for diabetes. Here, we describe a 3D culture system that supports the expansion of adult human pancreatic tissue and the generation of a cell subpopulation with progenitor characteristics. These cells display high aldehyde dehydrogenase activity (ALDHhi, express pancreatic progenitors markers (PDX1, PTF1A, CPA1, and MYC, and can form new organoids in contrast to ALDHlo cells. Interestingly, gene expression profiling revealed that ALDHhi cells are closer to human fetal pancreatic tissue compared with adult pancreatic tissue. Endocrine lineage markers were detected upon in vitro differentiation. Engrafted organoids differentiated toward insulin-positive (INS+ cells, and circulating human C-peptide was detected upon glucose challenge 1 month after transplantation. Engrafted ALDHhi cells formed INS+ cells. We conclude that adult human pancreatic tissue has potential for expansion into 3D structures harboring progenitor cells with endocrine differentiation potential. : In the context of β cell replacement therapy for diabetes, de Koning and colleagues describe a 3D culture platform that supports ex vivo expansion of human pancreatic tissue as organoids. These organoids harbor a subpopulation of ALDHhi cells that display proliferative capacity and can differentiate to an endocrine fate. Keywords: pancreas, organoid, human, ALDH, endocrine differentiation, beta cells, insulin, progenitor, fetal, diabetes

Insulin-Producing Endocrine Cells Differentiated In Vitro From Human Embryonic Stem Cells Function in Macroencapsulation Devices In Vivo.

Science.gov (United States)

Agulnick, Alan D; Ambruzs, Dana M; Moorman, Mark A; Bhoumik, Anindita; Cesario, Rosemary M; Payne, Janice K; Kelly, Jonathan R; Haakmeester, Carl; Srijemac, Robert; Wilson, Alistair Z; Kerr, Justin; Frazier, Mauro A; Kroon, Evert J; D'Amour, Kevin A

2015-10-01

The PEC-01 cell population, differentiated from human embryonic stem cells (hESCs), contains pancreatic progenitors (PPs) that, when loaded into macroencapsulation devices (to produce the VC-01 candidate product) and transplanted into mice, can mature into glucose-responsive insulin-secreting cells and other pancreatic endocrine cells involved in glucose metabolism. We modified the protocol for making PEC-01 cells such that 73%-80% of the cell population consisted of PDX1-positive (PDX1+) and NKX6.1+ PPs. The PPs were further differentiated to islet-like cells (ICs) that reproducibly contained 73%-89% endocrine cells, of which approximately 40%-50% expressed insulin. A large fraction of these insulin-positive cells were single hormone-positive and expressed the transcription factors PDX1 and NKX6.1. To preclude a significant contribution of progenitors to the in vivo function of ICs, we used a simple enrichment process to remove remaining PPs, yielding aggregates that contained 93%-98% endocrine cells and 1%-3% progenitors. Enriched ICs, when encapsulated and implanted into mice, functioned similarly to the VC-01 candidate product, demonstrating conclusively that in vitro-produced hESC-derived insulin-producing cells can mature and function in vivo in devices. A scaled version of our suspension culture was used, and the endocrine aggregates could be cryopreserved and retain functionality. Although ICs expressed multiple important β cell genes, the cells contained relatively low levels of several maturity-associated markers. Correlating with this, the time to function of ICs was similar to PEC-01 cells, indicating that ICs required cell-autonomous maturation after delivery in vivo, which would occur concurrently with graft integration into the host. Type 1 diabetes (T1D) affects approximately 1.25 million people in the U.S. alone and is deadly if not managed with insulin injections. This paper describes the production of insulin-producing cells in vitro and a new

Covalent cross-linking of insulin-like growth factor-1 to a specific inhibitor from human serum

International Nuclear Information System (INIS)

Ooi, G.T.; Herington, A.C.

1986-01-01

Previous studies have shown that a specific inhibitor of insulin-like growth factor (IGF) action in vitro can be isolated from normal human serum and subsequently partially purified on an IGF-affinity column. The ability of the inhibitor to bind the IGFs has now been confirmed directly using covalent cross-linking techniques. When 125 I-IGF-1 was cross-linked to inhibitor using disuccinimidyl suberate, five specifically labelled bands were seen on SDS-PAGE and autoradiography. Two bands (MW 21.5 K and 25.5 K) were intensely labelled, while the remaining three (MW 37 K, 34 K and 18 K) appeared as minor bands only. Inhibitor bioactivity, following further analysis by hydrophobic interaction chromatography or Con A-Sepharose affinity chromatography, was always associated with the presence of the 21.5 K and/or 25.5 K bands

FGF-2b and h-PL Transform Duct and Non-Endocrine Human Pancreatic Cells into Endocrine Insulin Secreting Cells by Modulating Differentiating Genes

Directory of Open Access Journals (Sweden)

Giulia Donadel

2017-10-01

Full Text Available Background: Diabetes mellitus (DM is a multifactorial disease orphan of a cure. Regenerative medicine has been proposed as novel strategy for DM therapy. Human fibroblast growth factor (FGF-2b controls β-cell clusters via autocrine action, and human placental lactogen (hPL-A increases functional β-cells. We hypothesized whether FGF-2b/hPL-A treatment induces β-cell differentiation from ductal/non-endocrine precursor(s by modulating specific genes expression. Methods: Human pancreatic ductal-cells (PANC-1 and non-endocrine pancreatic cells were treated with FGF-2b plus hPL-A at 500 ng/mL. Cytofluorimetry and Immunofluorescence have been performed to detect expression of endocrine, ductal and acinar markers. Bromodeoxyuridine incorporation and annexin-V quantified cells proliferation and apoptosis. Insulin secretion was assessed by RIA kit, and electron microscopy analyzed islet-like clusters. Results: Increase in PANC-1 duct cells de-differentiation into islet-like aggregates was observed after FGF-2b/hPL-A treatment showing ultrastructure typical of islets-aggregates. These clusters, after stimulation with FGF-2b/hPL-A, had significant (p < 0.05 increase in insulin, C-peptide, pancreatic and duodenal homeobox 1 (PDX-1, Nkx2.2, Nkx6.1, somatostatin, glucagon, and glucose transporter 2 (Glut-2, compared with control cells. Markers of PANC-1 (Cytokeratin-19, MUC-1, CA19-9 were decreased (p < 0.05. These aggregates after treatment with FGF-2b/hPL-A significantly reduced levels of apoptosis. Conclusions: FGF-2b and hPL-A are promising candidates for regenerative therapy in DM by inducing de-differentiation of stem cells modulating pivotal endocrine genes.

Hypoxia in Combination With Muscle Contraction Improves Insulin Action and Glucose Metabolism in Human Skeletal Muscle via the HIF-1α Pathway.

Science.gov (United States)

Görgens, Sven W; Benninghoff, Tim; Eckardt, Kristin; Springer, Christian; Chadt, Alexandra; Melior, Anita; Wefers, Jakob; Cramer, Andrea; Jensen, Jørgen; Birkeland, Kåre I; Drevon, Christian A; Al-Hasani, Hadi; Eckel, Jürgen

2017-11-01

Skeletal muscle insulin resistance is the hallmark of type 2 diabetes and develops long before the onset of the disease. It is well accepted that physical activity improves glycemic control, but the knowledge on underlying mechanisms mediating the beneficial effects remains incomplete. Exercise is accompanied by a decrease in intramuscular oxygen levels, resulting in induction of HIF-1α. HIF-1α is a master regulator of gene expression and might play an important role in skeletal muscle function and metabolism. Here we show that HIF-1α is important for glucose metabolism and insulin action in skeletal muscle. By using a genome-wide gene expression profiling approach, we identified RAB20 and TXNIP as two novel exercise/HIF-1α-regulated genes in skeletal muscle. Loss of Rab20 impairs insulin-stimulated glucose uptake in human and mouse skeletal muscle by blocking the translocation of GLUT4 to the cell surface. In addition, exercise/HIF-1α downregulates the expression of TXNIP , a well-known negative regulator of insulin action. In conclusion, we are the first to demonstrate that HIF-1α is a key regulator of glucose metabolism in skeletal muscle by directly controlling the transcription of RAB20 and TXNIP These results hint toward a novel function of HIF-1α as a potential pharmacological target to improve skeletal muscle insulin sensitivity. © 2017 by the American Diabetes Association.

Activation of peroxisome proliferator-activated receptor-{alpha} enhances fatty acid oxidation in human adipocytes

Energy Technology Data Exchange (ETDEWEB)

Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kawada, Teruo, E-mail: fat@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2011-04-22

Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. {yields} PPAR{alpha} activation also increased insulin-dependent glucose uptake in human adipocytes. {yields} PPAR{alpha} activation did not affect lipid accumulation in human adipocytes. {yields} PPAR{alpha} activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPAR{alpha} in adipocytes have been unclarified. We examined the functions of PPAR{alpha} using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPAR{alpha} by GW7647, a potent PPAR{alpha} agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPAR{gamma}, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPAR{alpha} activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPAR{gamma} is activated. On the other hand, PPAR{alpha} activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPAR{alpha}-dependent manner. Moreover, PPAR{alpha} activation increased the production of CO{sub 2} and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPAR{alpha} stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPAR{alpha} agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected

Enrichment of human embryonic stem cell-derived NKX6.1-expressing pancreatic progenitor cells accelerates the maturation of insulin-secreting cells in vivo.

Science.gov (United States)

Rezania, Alireza; Bruin, Jennifer E; Xu, Jean; Narayan, Kavitha; Fox, Jessica K; O'Neil, John J; Kieffer, Timothy J

2013-11-01

Human embryonic stem cells (hESCs) are considered a potential alternative to cadaveric islets as a source of transplantable cells for treating patients with diabetes. We previously described a differentiation protocol to generate pancreatic progenitor cells from hESCs, composed of mainly pancreatic endoderm (PDX1/NKX6.1-positive), endocrine precursors (NKX2.2/synaptophysin-positive, hormone/NKX6.1-negative), and polyhormonal cells (insulin/glucagon-positive, NKX6.1-negative). However, the relative contributions of NKX6.1-negative versus NKX6.1-positive cell fractions to the maturation of functional β-cells remained unclear. To address this question, we generated two distinct pancreatic progenitor cell populations using modified differentiation protocols. Prior to transplant, both populations contained a high proportion of PDX1-expressing cells (~85%-90%) but were distinguished by their relatively high (~80%) or low (~25%) expression of NKX6.1. NKX6.1-high and NKX6.1-low progenitor populations were transplanted subcutaneously within macroencapsulation devices into diabetic mice. Mice transplanted with NKX6.1-low cells remained hyperglycemic throughout the 5-month post-transplant period whereas diabetes was reversed in NKX6.1-high recipients within 3 months. Fasting human C-peptide levels were similar between groups throughout the study, but only NKX6.1-high grafts displayed robust meal-, glucose- and arginine-responsive insulin secretion as early as 3 months post-transplant. NKX6.1-low recipients displayed elevated fasting glucagon levels. Theracyte devices from both groups contained almost exclusively pancreatic endocrine tissue, but NKX6.1-high grafts contained a greater proportion of insulin-positive and somatostatin-positive cells, whereas NKX6.1-low grafts contained mainly glucagon-expressing cells. Insulin-positive cells in NKX6.1-high, but not NKX6.1-low grafts expressed nuclear MAFA. Collectively, this study demonstrates that a pancreatic endoderm

Effects of insulin detemir and NPH insulin on renal handling of sodium, fluid retention and weight in type 2 diabetic patients

DEFF Research Database (Denmark)

Hendriksen, K V; Jensen, Tonny Joran; Oturai, P

2012-01-01

In type 2 diabetic patients, insulin detemir (B29Lys(ε-tetradecanoyl),desB30 human insulin) induces less weight gain than NPH insulin. Due to the proposed reduction of tubular action by insulin detemir, type 2 diabetic patients should have increased urinary sodium excretion, thereby reducing extr...

Browning of Subcutaneous White Adipose Tissue in Humans

OpenAIRE

Sidossis, Labros S.; Porter, Craig; Saraf, Manish K.; Børsheim, Elisabet; Radhakrishnan, Ravi S.; Chao, Tony; Ali, Arham; Chondronikola, Maria; Mlcak, Ronald; Finnerty, Celeste C.; Hawkins, Hal K.; Toliver-Kinsky, Tracy; Herndon, David N.

2015-01-01

Since the presence of brown adipose tissue (BAT) was confirmed in adult humans, BAT has become a therapeutic target for obesity and insulin resistance. We examined whether human subcutaneous white adipose tissue (sWAT) can adopt a BAT-like phenotype using a clinical model of prolonged and severe adrenergic stress. sWAT samples were collected from severely burned and healthy individuals. A subset of burn victims were prospectively followed during their acute hospitalization. Browning of sWAT w...

Tau hyperphosphorylation induces oligomeric insulin accumulation and insulin resistance in neurons.

Science.gov (United States)

Rodriguez-Rodriguez, Patricia; Sandebring-Matton, Anna; Merino-Serrais, Paula; Parrado-Fernandez, Cristina; Rabano, Alberto; Winblad, Bengt; Ávila, Jesús; Ferrer, Isidre; Cedazo-Minguez, Angel

2017-12-01

Insulin signalling deficiencies and insulin resistance have been directly linked to the progression of neurodegenerative disorders like Alzheimer's disease. However, to date little is known about the underlying molecular mechanisms or insulin state and distribution in the brain under pathological conditions. Here, we report that insulin is accumulated and retained as oligomers in hyperphosphorylated tau-bearing neurons in Alzheimer's disease and in several of the most prevalent human tauopathies. The intraneuronal accumulation of insulin is directly dependent on tau hyperphosphorylation, and follows the tauopathy progression. Furthermore, cells accumulating insulin show signs of insulin resistance and decreased insulin receptor levels. These results suggest that insulin retention in hyperphosphorylated tau-bearing neurons is a causative factor for the insulin resistance observed in tauopathies, and describe a novel neuropathological concept with important therapeutic implications. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cryopreservation of human insulin expressing cells macro-encapsulated in a durable therapeutic immunoisolating device theracyte.

Science.gov (United States)

Yakhnenko, Ilya; Wong, Wallace K; Katkov, Igor I; Itkin-Ansari, Pamela

2012-01-01

Encapsulating insulin producing cells (INPCs) in an immunoisolation device have been shown to cure diabetes in rodents without the need for immunosuppression. However, micro-encapsulation in semi-solid gels raises longevity and safety concerns for future use of stem cell derived INPCs. We have focused on a durable and retrievable macro-encapsulation (> 10(6) cells) device (TheraCyte). Cryopreservation (CP) of cells preloaded into the device is highly desirable but may require prolonged exposure to cryoprotectants during loading and post-thaw manipulations. Here, we are reporting survival and function of a human islet cell line frozen as single cells or as islet-like cell clusters. The non-clusterized cells exhibited high cryosurvival after prolonged pre-freeze or post-thaw exposure to 10 percent DMSO. However, both clusterization and especially loading INPCs into the device reduced viable yield even without CP. The survived cryopreserved macro-encapsulated INPCs remained fully functional suggesting that CP of macro-encapsulated cells is a promising tool for cell based therapies.

The SNARE protein SNAP23 and the SNARE-interacting protein Munc18c in human skeletal muscle are implicated in insulin resistance/type 2 diabetes

DEFF Research Database (Denmark)

Boström, Pontus; Andersson, Linda; Vind, Birgitte

2010-01-01

/cytosolic compartment in the patients with the type 2 diabetes. Expression of the SNARE-interacting protein Munc18c was higher in skeletal muscle from patients with type 2 diabetes. Studies in L6 cells showed that Munc18c promoted the expression of SNAP23. CONCLUSIONS: We have translated our previous in vitro results......OBJECTIVE: Our previous studies suggest that the SNARE protein synaptosomal-associated protein of 23 kDa (SNAP23) is involved in the link between increased lipid levels and insulin resistance in cardiomyocytes. The objective was to determine whether SNAP23 may also be involved in the known...... association between lipid accumulation in skeletal muscle and insulin resistance/type 2 diabetes in humans, as well as to identify a potential regulator of SNAP23. RESEARCH DESIGN AND METHODS: We analyzed skeletal muscle biopsies from patients with type 2 diabetes and healthy, insulin-sensitive control...

Generation of Functional Beta-Like Cells from Human Exocrine Pancreas.

Directory of Open Access Journals (Sweden)

Maria J Lima

Full Text Available Transcription factor mediated lineage reprogramming of human pancreatic exocrine tissue could conceivably provide an unlimited supply of islets for transplantation in the treatment of diabetes. Exocrine tissue can be efficiently reprogrammed to islet-like cells using a cocktail of transcription factors: Pdx1, Ngn3, MafA and Pax4 in combination with growth factors. We show here that overexpression of exogenous Pax4 in combination with suppression of the endogenous transcription factor ARX considerably enhances the production of functional insulin-secreting β-like cells with concomitant suppression of α-cells. The efficiency was further increased by culture on laminin-coated plates in media containing low glucose concentrations. Immunocytochemistry revealed that reprogrammed cultures were composed of ~45% islet-like clusters comprising >80% monohormonal insulin+ cells. The resultant β-like cells expressed insulin protein levels at ~15-30% of that in adult human islets, efficiently processed proinsulin and packaged insulin into secretory granules, exhibited glucose responsive insulin secretion, and had an immediate and prolonged effect in normalising blood glucose levels upon transplantation into diabetic mice. We estimate that approximately 3 billion of these cells would have an immediate therapeutic effect following engraftment in type 1 diabetes patients and that one pancreas would provide sufficient tissue for numerous transplants.

A low dose lipid infusion is sufficient to induce insulin resistance and a pro-inflammatory response in human subjects.

Science.gov (United States)

Liang, Hanyu; Lum, Helen; Alvarez, Andrea; Garduno-Garcia, Jose de Jesus; Daniel, Benjamin J; Musi, Nicolas

2018-01-01

The root cause behind the low-grade inflammatory state seen in insulin resistant (obesity and type 2 diabetes) states is unclear. Insulin resistant subjects have elevations in plasma free fatty acids (FFA), which are ligands for the pro-inflammatory toll-like receptor (TLR)4 pathway. We tested the hypothesis that an experimental elevation in plasma FFA (within physiological levels) in lean individuals would upregulate TLR4 and activate downstream pathways (e.g., MAPK) in circulating monocytes. Twelve lean, normal glucose-tolerant subjects received a low dose (30 ml/h) 48 h lipid or saline infusion on two different occasions. Monocyte TLR4 protein level, MAPK phosphorylation, and expression of genes in the TLR pathway were determined before and after each infusion. The lipid infusion significantly increased monocyte TLR4 protein and phosphorylation of JNK and p38 MAPK. Lipid-mediated increases in TLR4 and p38 phosphorylation directly correlated with reduced peripheral insulin sensitivity (M value). Lipid increased levels of multiple genes linked to inflammation, including several TLRs, CD180, MAP3K7, and CXCL10. Monocytes exposed in vivo to lipid infusion exhibited enhanced in vitro basal and LPS-stimulated IL-1β secretion. In lean subjects, a small increase in plasma FFA (as seen in insulin resistant subjects) is sufficient to upregulate TLR4 and stimulate inflammatory pathways (MAPK) in monocytes. Moreover, lipids prime monocytes to endotoxin. We provide proof-of-concept data in humans indicating that the low-grade inflammatory state characteristic of obesity and type 2 diabetes could be caused (at least partially) by pro-inflammatory monocytes activated by excess lipids present in these individuals.

Receptor-isoform-selective insulin analogues give tissue-preferential effects

DEFF Research Database (Denmark)

Vienberg, Sara Gry; Bouman, Stephan D; Sørensen, Heidi

2011-01-01

The relative expression patterns of the two IR (insulin receptor) isoforms, +/- exon 11 (IR-B/IR-A respectively), are tissue-dependent. Therefore we have developed insulin analogues with different binding affinities for the two isoforms to test whether tissue-preferential biological effects can...... be attained. In rats and mice, IR-B is the most prominent isoform in the liver (> 95%) and fat (> 90%), whereas in muscles IR-A is the dominant isoform (> 95%). As a consequence, the insulin analogue INS-A, which has a higher relative affinity for human IR-A, had a higher relative potency [compared with HI...... (human insulin)] for glycogen synthesis in rat muscle strips (26%) than for glycogen accumulation in rat hepatocytes (5%) and for lipogenesis in rat adipocytes (4%). In contrast, the INS-B analogue, which has an increased affinity for human IR-B, had higher relative potencies (compared with HI...

Novel covalently linked insulin dimer engineered to investigate the function of insulin dimerization

DEFF Research Database (Denmark)

Vinther, Tine N.; Norrman, Mathias; Strauss, Holger M.

2012-01-01

An ingenious system evolved to facilitate insulin binding to the insulin receptor as a monomer and at the same time ensure sufficient stability of insulin during storage. Insulin dimer is the cornerstone of this system. Insulin dimer is relatively weak, which ensures dissociation into monomers...... in the circulation, and it is stabilized by hexamer formation in the presence of zinc ions during storage in the pancreatic ß-cell. Due to the transient nature of insulin dimer, direct investigation of this important form is inherently difficult. To address the relationship between insulin oligomerization...... and insulin stability and function, we engineered a covalently linked insulin dimer in which two monomers were linked by a disulfide bond. The structure of this covalent dimer was identical to the self-association dimer of human insulin. Importantly, this covalent dimer was capable of further oligomerization...

Insulin analogues: have they changed insulin treatment and improved glycaemic control?

DEFF Research Database (Denmark)

Madsbad, Sten

2002-01-01

To improve insulin therapy, new insulin analogues have been developed. Two fast-acting analogues with a more rapid onset of effect and a shorter duration of action combined with a low day-to-day variation in absorption rate are now available. Despite this favourable time-action profile most studies....... This is probably the main explanation for the absence of improvement in overall glycaemic control when compared with regular human insulin. A tendency to a reduction in hypoglycaemic events during treatment with fast-acting analogues has been observed in most studies. Recent studies have indicated that NPH insulin...... administered several times daily at mealtimes can improve glycaemic control without increasing the risk of hypoglycaemia. The fast-acting analogues are now also available as insulin mixed with NPH. Insulin glargine is a new long-acting insulin which is soluble and precipitates after injection, resulting...

In vitro and in vivo potency of insulin analogues designed for clinical use.

Science.gov (United States)

Vølund, A; Brange, J; Drejer, K; Jensen, I; Markussen, J; Ribel, U; Sørensen, A R; Schlichtkrull, J

1991-11-01

Analogues of human insulin designed to have improved absorption properties after subcutaneous injection have been prepared by recombinant DNA technology. Five rapidly absorbed analogues, being predominantly in mono- or di-meric states in the pharmaceutical preparation, and a hexameric analogue with very low solubility at neutral pH and slow absorption, were studied. Receptor binding assays with HEP-G2 cells showed overall agreement with mouse free adipocyte assays. Two analogues, B28Asp and A21Gly + B27Arg + B30Thr-NH2, had nearly the same molar in vitro potency as human insulin. Another two showed increased adipocyte potency and receptor binding, B10Asp 194% and 333% and A8His + B4His + B10Glu + B27His 575% and 511%, while B9Asp + B27Glu showed 29% and 18% and the B25Asp analogue only 0.12% and 0.05% potency. Bioassays in mice or rabbits of the analogues except B25Asp showed that they had the same in vivo potency as human insulin 1.00 IU = 6.00 nmol. Thus the variation had the same in vivo potency as human insulin 1.00 IU = 6.00 nmol. Thus the variation in in vivo potency reflects the differences in receptor binding affinity. Relative to human insulin a low concentration is sufficient for a high affinity analogue to produce a given receptor complex formation and metabolic response. In conclusion, human insulin and analogues with markedly different in vitro potencies were equipotent in terms of hypoglycaemic effect. This is in agreement with the concept that elimination of insulin from blood and its subsequent degradation is mediated by insulin receptors.

Mesenchymal stromal cells improve human islet function through released products and extracellular matrix.

Science.gov (United States)

Arzouni, Ahmed A; Vargas-Seymour, Andreia; Rackham, Chloe L; Dhadda, Paramjeet; Huang, Guo-Cai; Choudhary, Pratik; Nardi, Nance; King, Aileen J F; Jones, Peter M

2017-12-01

The aims of the present study were (i) to determine whether the reported beneficial effects of mesenchymal stromal cells (MSCs) on mouse islet function extend to clinically relevant human tissues (islets and MSCs), enabling translation into improved protocols for clinical human islet transplantation; and (ii) to identify possible mechanisms through which human MSCs influence human islet function. Human islets were co-cultured with human adipose tissue-derived MSCs (hASCs) or pre-treated with its products - extracellular matrix (ECM) and annexin A1 (ANXA1). Mouse islets were pre-treated with mouse MSC-derived ECM. Islet insulin secretory function was assessed in vitro by radioimmunoassay. Quantitative RT-PCR was used to screen human adipMSCs for potential ligands of human islet G-protein-coupled receptors. We show that co-culture with hASCs improves human islet secretory function in vitro , as measured by glucose-stimulated insulin secretion, confirming previous reports using rodent tissues. Furthermore, we demonstrate that these beneficial effects on islet function can be partly attributed to the MSC-derived products ECM and ANXA1. Our results suggest that hASCs have the potential to improve the quality of human islets isolated for transplantation therapy of Type 1 diabetes. Furthermore, it may be possible to achieve improvements in human islet quality in a cell-free culture system by using the MSC-derived products ANXA1 and ECM. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Cytotoxicity of human pI 7 interleukin-1 for pancreatic islets of Langerhans

DEFF Research Database (Denmark)

Bendtzen, K; Mandrup-Poulsen, T; Nerup, J

1986-01-01

Activated mononuclear cells appear to be important effector cells in autoimmune beta cell destruction leading to insulin-dependent (type 1) diabetes mellitus. Conditioned medium from activated mononuclear cells (from human blood) is cytotoxic to isolated rat and human islets of Langerhans. This c...

Biochemical characterization of individual human glycosylated pro-insulin-like growth factor (IGF)-II and big-IGF-II isoforms associated with cancer.

Science.gov (United States)

Greenall, Sameer A; Bentley, John D; Pearce, Lesley A; Scoble, Judith A; Sparrow, Lindsay G; Bartone, Nicola A; Xiao, Xiaowen; Baxter, Robert C; Cosgrove, Leah J; Adams, Timothy E

2013-01-04

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed "pro" and "big" IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling.

Biochemical Characterization of Individual Human Glycosylated pro-Insulin-like Growth Factor (IGF)-II and big-IGF-II Isoforms Associated with Cancer

Science.gov (United States)

Greenall, Sameer A.; Bentley, John D.; Pearce, Lesley A.; Scoble, Judith A.; Sparrow, Lindsay G.; Bartone, Nicola A.; Xiao, Xiaowen; Baxter, Robert C.; Cosgrove, Leah J.; Adams, Timothy E.

2013-01-01

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed “pro” and “big” IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling. PMID:23166326

Composition and function of macroencapsulated human embryonic stem cell-derived implants: comparison with clinical human islet cell grafts.

Science.gov (United States)

Motté, Evi; Szepessy, Edit; Suenens, Krista; Stangé, Geert; Bomans, Myriam; Jacobs-Tulleneers-Thevissen, Daniel; Ling, Zhidong; Kroon, Evert; Pipeleers, Daniel

2014-11-01

β-Cells generated from large-scale sources can overcome current shortages in clinical islet cell grafts provided that they adequately respond to metabolic variations. Pancreatic (non)endocrine cells can develop from human embryonic stem (huES) cells following in vitro derivation to pancreatic endoderm (PE) that is subsequently implanted in immune-incompetent mice for further differentiation. Encapsulation of PE increases the proportion of endocrine cells in subcutaneous implants, with enrichment in β-cells when they are placed in TheraCyte-macrodevices and predominantly α-cells when they are alginate-microencapsulated. At posttransplant (PT) weeks 20-30, macroencapsulated huES implants presented higher glucose-responsive plasma C-peptide levels and a lower proinsulin-over-C-peptide ratio than human islet cell implants under the kidney capsule. Their ex vivo analysis showed the presence of single-hormone-positive α- and β-cells that exhibited rapid secretory responses to increasing and decreasing glucose concentrations, similar to isolated human islet cells. However, their insulin secretory amplitude was lower, which was attributed in part to a lower cellular hormone content; it was associated with a lower glucose-induced insulin biosynthesis, but not with lower glucagon-induced stimulation, which together is compatible with an immature functional state of the huES-derived β-cells at PT weeks 20-30. These data support the therapeutic potential of macroencapsulated huES implants but indicate the need for further functional analysis. Their comparison with clinical-grade human islet cell grafts sets references for future development and clinical translation. Copyright © 2014 the American Physiological Society.

Lipid droplets hypertrophy: a crucial determining factor in insulin regulation by adipocytes

Science.gov (United States)

Sanjabi, Bahram; Dashty, Monireh; Özcan, Behiye; Akbarkhanzadeh, Vishtaseb; Rahimi, Mehran; Vinciguerra, Manlio; van Rooij, Felix; Al-Lahham, Saad; Sheedfar, Fareeba; van Kooten, Theo G.; Spek, C. Arnold; Rowshani, Ajda T.; van der Want, Johannes; Klaassen, Rene; Sijbrands, Eric; Peppelenbosch, Maikel P.; Rezaee, Farhad

2015-03-01

Lipid droplets (LDs) hypertrophy in adipocytes is the main cause of energy metabolic system dysfunction, obesity and its afflictions such as T2D. However, the role of adipocytes in linking energy metabolic disorders with insulin regulation is unknown in humans. Human adipocytes constitutively synthesize and secrete insulin, which is biologically functional. Insulin concentrations and release are fat mass- and LDs-dependent respectively. Fat reduction mediated by bariatric surgery repairs obesity-associated T2D. The expression of genes, like PCSK1 (proinsulin conversion enzyme), GCG (Glucagon), GPLD1, CD38 and NNAT, involved in insulin regulation/release were differentially expressed in pancreas and adipose tissue (AT). INS (insulin) and GCG expression reduced in human AT-T2D as compared to AT-control, but remained unchanged in pancreas in either state. Insulin levels (mRNA/protein) were higher in AT derived from prediabetes BB rats with destructed pancreatic β-cells and controls than pancreas derived from the same rats respectively. Insulin expression in 10 human primary cell types including adipocytes and macrophages is an evidence for extrapancreatic insulin-producing cells. The data suggest a crosstalk between AT and pancreas to fine-tune energy metabolic system or may minimize the metabolic damage during diabetes. This study opens new avenues towards T2D therapy with a great impact on public health.

Human Rights, Human Needs, Human Development, Human Security

OpenAIRE

Gasper, Des

2009-01-01

Human rights, human development and human security form increasingly important, partly interconnected, partly competitive and misunderstood ethical and policy discourses. Each tries to humanize a pre-existing and unavoidable major discourse of everyday life, policy and politics; each has emerged within the United Nations world; each relies implicitly on a conceptualisation of human need; each has specific strengths. Yet mutual communication, understanding and co-operation are deficient, espec...

Studies on insulin receptor, 1

International Nuclear Information System (INIS)

Sakai, Yukio

1979-01-01

The present study was designed for the purpose of establishing a method of insulin radioreceptor assay using plasma membranes of guinea pigs as receptor sites. The results obtained are as follows: 1) Insulin receptor in the renal plasma membranes of guinea pigs showed a significantly high affinity to porcine insulin compared with that in the plasma membranes of guinea pig liver or rat kidney and liver. 2) In the insulin radioreceptor assay, an optimum condition was observed by the incubation at 4 0 C for 24 - 48 hours with 100 μg membrane protein of guinea pig kidney and 0.08 ng of 125 I-insulin. This assay method was specific for insulin and showed an accurate biological activity of insulin. 3) The recovery rate of insulin radioreceptor assay was 98.4% and dilution check up to 16 times did not influence on the result. An average of coefficient variation was 3.92% within assay. All of these results indicated the method to be satisfactory. 4) Glucose induced insulin release by perfusion method in isolated Langerhans islets of rats showed an identical pattern of reaction curves between radioreceptor assay and radioimmunoassay, although the values of radioreceptor assay was slightly low. 5) Insulin free serum produced by ultra filtration method was added to the standard assay medium. By this procedure, direct measurement of human serum by radioreceptor assay became possible. 6) The value of human serum insulin receptor binding activity by the radioreceptor assay showed a high correlation with that of insulin radioimmunoassay in sera of normal, borderline or diabetic type defined by glucose tolerance test. (author)

Effect of sleep deprivation on the human metabolome

NARCIS (Netherlands)

S.K. Davies (Sarah); J.E. Ang (Joo Ern); V.L. Revell (Victoria); B. Holmes (Ben); A. Mann (Anuska); F.P. Robertson (Francesca); N. Cui (Nanyi); B. Middleton (Benita); K. Ackermann (Katrin); M.H. Kayser (Manfred); A.E. Thumser (Alfred); P. Raynaud (Philippe); D.J. Skene (Debra)

2014-01-01

textabstractSleep restriction and circadian clock disruption are associated with metabolic disorders such as obesity, insulin resistance, and diabetes. The metabolic pathways involved in human sleep, however, have yet to be investigatedwith the use of a metabolomics approach. Here we have used

Insulin-like activity in the retina

International Nuclear Information System (INIS)

Das, A.

1986-01-01

A number of studies have recently demonstrated that insulin or a homologous peptide may be synthesized outside the pancreas also. The present study was designed to investigate whether insulin-like activity exists in the retina, and if it exists, whether it is due to local synthesis of insulin or a similar peptide in the retina. To determine whether the insulin-like immunoreactivity in retinal glial cells is due to binding and uptake or local synthesis of insulin, a combined approach of immunocytochemistry and in situ DNA-RNA hybridization techniques was used on cultured rat retinal glial cells. Insulin-like immunoreactivity was demonstrated in the cytoplasma of these cells. In situ hybridization studies using labeled rat insulin cDNA indicated that these cells contain the mRNA necessary for de novo synthesis of insulin or a closely homologous peptide. Since human retinal cells have, as yet, not been conveniently grown in culture, an ocular tumor cell line, human Y79 retinoblastoma was used as a model to extend these investigations. The presence of insulin-like immunoreactivity as well as insulin-specific mRNA was demonstrated in this cell line. Light microscopic autoradiography following incubation of isolated rat retinal cells with 125 I-insulin showed the presence of insulin binding sites on the photoreceptors and amarcine cells. On the basis of these observations that rat retina glial cells, including Muller cells are sites of synthesis of insulin or a similar peptide, a model for the pathogenesis of dabetic retinopathy is proposed

Self-renewal of human embryonic stem cells requires insulin-like growth factor-1 receptor and ERBB2 receptor signaling

Science.gov (United States)

Wang, Linlin; Schulz, Thomas C.; Sherrer, Eric S.; Dauphin, Derek S.; Shin, Soojung; Nelson, Angelique M.; Ware, Carol B.; Zhan, Mei; Song, Chao-Zhong; Chen, Xiaoji; Brimble, Sandii N.; McLean, Amanda; Galeano, Maria J.; Uhl, Elizabeth W.; D'Amour, Kevin A.; Chesnut, Jonathan D.; Rao, Mahendra S.

2007-01-01

Despite progress in developing defined conditions for human embryonic stem cell (hESC) cultures, little is known about the cell-surface receptors that are activated under conditions supportive of hESC self-renewal. A simultaneous interrogation of 42 receptor tyrosine kinases (RTKs) in hESCs following stimulation with mouse embryonic fibroblast (MEF) conditioned medium (CM) revealed rapid and prominent tyrosine phosphorylation of insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R); less prominent tyrosine phosphorylation of epidermal growth factor receptor (EGFR) family members, including ERBB2 and ERBB3; and trace phosphorylation of fibroblast growth factor receptors. Intense IGF1R and IR phosphorylation occurred in the absence of MEF conditioning (NCM) and was attributable to high concentrations of insulin in the proprietary KnockOut Serum Replacer (KSR). Inhibition of IGF1R using a blocking antibody or lentivirus-delivered shRNA reduced hESC self-renewal and promoted differentiation, while disruption of ERBB2 signaling with the selective inhibitor AG825 severely inhibited hESC proliferation and promoted apoptosis. A simple defined medium containing an IGF1 analog, heregulin-1β (a ligand for ERBB2/ERBB3), fibroblast growth factor-2 (FGF2), and activin A supported long-term growth of multiple hESC lines. These studies identify previously unappreciated RTKs that support hESC proliferation and self-renewal, and provide a rationally designed medium for the growth and maintenance of pluripotent hESCs. PMID:17761519

The human hepatocyte cell lines IHH and HepaRG: models to study glucose, lipid and lipoprotein metabolism.

Science.gov (United States)

Samanez, Carolina Huaman; Caron, Sandrine; Briand, Olivier; Dehondt, Hélène; Duplan, Isabelle; Kuipers, Folkert; Hennuyer, Nathalie; Clavey, Véronique; Staels, Bart

2012-07-01

Metabolic diseases reach epidemic proportions. A better knowledge of the associated alterations in the metabolic pathways in the liver is necessary. These studies need in vitro human cell models. Several human hepatoma models are used, but the response of many metabolic pathways to physiological stimuli is often lost. Here, we characterize two human hepatocyte cell lines, IHH and HepaRG, by analysing the expression and regulation of genes involved in glucose and lipid metabolism. Our results show that the glycolysis pathway is activated by glucose and insulin in both lines. Gluconeogenesis gene expression is induced by forskolin in IHH cells and inhibited by insulin in both cell lines. The lipogenic pathway is regulated by insulin in IHH cells. Finally, both cell lines secrete apolipoprotein B-containing lipoproteins, an effect promoted by increasing glucose concentrations. These two human cell lines are thus interesting models to study the regulation of glucose and lipid metabolism.

Construction of engineering adipose-like tissue in vivo utilizing human insulin gene-modified umbilical cord mesenchymal stromal cells with silk fibroin 3D scaffolds.

Science.gov (United States)

Li, Shi-Long; Liu, Yi; Hui, Ling

2015-12-01

We evaluated the use of a combination of human insulin gene-modified umbilical cord mesenchymal stromal cells (hUMSCs) with silk fibroin 3D scaffolds for adipose tissue engineering. In this study hUMSCs were isolated and cultured. HUMSCs infected with Ade-insulin-EGFP were seeded in fibroin 3D scaffolds with uniform 50-60 µm pore size. Silk fibroin scaffolds with untransfected hUMSCs were used as control. They were cultured for 4 days in adipogenic medium and transplanted under the dorsal skins of female Wistar rats after the hUMSCs had been labelled with chloromethylbenzamido-1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (CM-Dil). Macroscopical impression, fluorescence observation, histology and SEM were used for assessment after transplantation at 8 and 12 weeks. Macroscopically, newly formed adipose tissue was observed in the experimental group and control group after 8 and 12 weeks. Fluorescence observation supported that the formed adipose tissue originated from seeded hUMSCs rather than from possible infiltrating perivascular tissue. Oil red O staining of newly formed tissue showed that there was substantially more tissue regeneration in the experimental group than in the control group. SEM showed that experimental group cells had more fat-like cells, whose volume was larger than that of the control group, and degradation of the silk fibroin scaffold was greater under SEM observation. This study provides significant evidence that hUMSCs transfected by adenovirus vector have good compatibility with silk fibroin scaffold, and adenoviral transfection of the human insulin gene can be used for the construction of tissue-engineered adipose. Copyright © 2013 John Wiley & Sons, Ltd.

Improved function and proliferation of adult human beta cells engrafted in diabetic immunodeficient NOD-scid IL2rγnull mice treated with alogliptin

Directory of Open Access Journals (Sweden)

Jurczyk A

2013-12-01

Full Text Available Agata Jurczyk,1 Philip diIorio,1 Dean Brostowin,1 Linda Leehy,1 Chaoxing Yang,1 Fumihiko Urano,2 David M Harlan,3 Leonard D Shultz,4 Dale L Greiner,1 Rita Bortell1 1Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 2Department of Medicine, Washington University School of Medicine, St Louis, MO, 3Department of Medicine, University of Massachusetts Medical School, Worcester, MA, 4The Jackson Laboratory, Bar Harbor, ME, USA Purpose: Dipeptidyl-peptidase-4 (DPP-4 inhibitors are known to increase insulin secretion and beta cell proliferation in rodents. To investigate the effects on human beta cells in vivo, we utilize immunodeficient mice transplanted with human islets. The study goal was to determine the efficacy of alogliptin, a DPP-4 inhibitor, to enhance human beta cell function and proliferation in an in vivo context using diabetic immunodeficient mice engrafted with human pancreatic islets. Methods: Streptozotocin-induced diabetic NOD-scid IL2rγnull (NSG mice were transplanted with adult human islets in three separate trials. Transplanted mice were treated daily by gavage with alogliptin (30 mg/kg/day or vehicle control. Islet graft function was compared using glucose tolerance tests and non-fasting plasma levels of human insulin and C-peptide; beta cell proliferation was determined by bromodeoxyuridine (BrdU incorporation. Results: Glucose tolerance tests were significantly improved by alogliptin treatment for mice transplanted with islets from two of the three human islet donors. Islet-engrafted mice treated with alogliptin also had significantly higher plasma levels of human insulin and C-peptide compared to vehicle controls. The percentage of insulin+BrdU+ cells in human islet grafts from alogliptin-treated mice was approximately 10-fold more than from vehicle control mice, consistent with a significant increase in human beta cell proliferation. Conclusion: Human islet-engrafted immunodeficient mice

Grizzly bears exhibit augmented insulin sensitivity while obese prior to a reversible insulin resistance during hibernation.

Science.gov (United States)

Nelson, O Lynne; Jansen, Heiko T; Galbreath, Elizabeth; Morgenstern, Kurt; Gehring, Jamie Lauren; Rigano, Kimberly Scott; Lee, Jae; Gong, Jianhua; Shaywitz, Adam J; Vella, Chantal A; Robbins, Charles T; Corbit, Kevin C

2014-08-05

The confluence of obesity and diabetes as a worldwide epidemic necessitates the discovery of new therapies. Success in this endeavor requires translatable preclinical studies, which traditionally employ rodent models. As an alternative approach, we explored hibernation where obesity is a natural adaptation to survive months of fasting. Here we report that grizzly bears exhibit seasonal tripartite insulin responsiveness such that obese animals augment insulin sensitivity but only weeks later enter hibernation-specific insulin resistance (IR) and subsequently reinitiate responsiveness upon awakening. Preparation for hibernation is characterized by adiposity coupled to increased insulin sensitivity via modified PTEN/AKT signaling specifically in adipose tissue, suggesting a state of "healthy" obesity analogous to humans with PTEN haploinsufficiency. Collectively, we show that bears reversibly cope with homeostatic perturbations considered detrimental to humans and describe a mechanism whereby IR functions not as a late-stage metabolic adaptation to obesity, but rather a gatekeeper of the fed-fasting transition. Copyright © 2014 Elsevier Inc. All rights reserved.

Will availability of inhaled human insulin (Exubera® improve management of type 2 diabetes? The design of the Real World trial

Directory of Open Access Journals (Sweden)

Freemantle Nick

2006-08-01

Full Text Available Abstract Background Common deterrents to insulin therapy for both physicians and patients are the complexity and burden of daily injections. In January 2006, the first inhaled human insulin (INH, Exubera® (insulinhuman [rDNA origin]InhalationPowder was approved for use in adult patients with type 1 diabetes mellitus (T1DM or type 2 diabetes mellitus (T2DM in the United States and European Union. Results from the INH clinical trial program have shown comparable efficacy of INH to subcutaneous (SC insulin and superior efficacy versus oral antidiabetic agents; thus providing effective glycemic control in adult patients with T2DM without the requirement for preprandial injections. However, because subjects in those trials were randomized to either INH or an alternative, the studies could not estimate the effect of INH on patient acceptance of insulin therapy. Therefore, traditional study designs cannot provide answers to important and practical questions regarding real world effectiveness, which is influenced by psychological and other access barriers. Methods To overcome these limitations, the Real World Trial was designed to estimate the effect of the availability of INH as a treatment option for glycemic control. A total of approximately 700 patients from Canada, France, Germany, Italy, Spain, United Kingdom, and the United States with T2DM poorly controlled by oral agent therapy will be randomized to two different treatment settings. Patients and clinicians in both groups (A & B may choose from all licensed therapies for diabetes including SC insulin delivered by pens; INH will be an additional treatment option only available in Group A. The Real World Trial (Protocol A2171018 has been registered with ClincalTrials.gov, registration id NCT00134147. Results The primary outcome for the trial will be the difference in mean glycosylated hemoglobin (HbA1c at 6 months between groups. The design was based on a preceding feasibility study examining the

Microvascular Recruitment in Insulin Resistance

DEFF Research Database (Denmark)

Sjøberg, Kim Anker

the resonating sound from the microbubbles in the systemic circulation were recorded for determination of microvascular recruitment in designated muscle segments. Results showed that microvascular recruitment increased with insulin stimulation by ~30% in rats and ~40% in humans (study I). Furthermore......, it was observed that muscle contractions increased muscle perfusion rapidly by 3-4 fold and by 1-2 fold compared to basal and insulin, respectively, in both rat and human skeletal muscle (study I). The real-time contrast-enhanced ultrasound method was applied to investigate the vaso-active effect of the incretin...... hormone glucagon-like-peptide-1 (GLP-1) in the microcirculation. Glucagon-like-peptide-1 analogs are drugs used for treatments of insulin resistance and type 2 diabetes but the vascular effects of GLP-1 in vivo are elusive. Here it was shown that GLP-1 rapidly increased the microvascular recruitment...

The effect of mutations on the structure of insulin fibrils studied by Fourier transform infrared (FTIR) spectroscopy and electron microscopy.

Science.gov (United States)

Garriques, Liza Nielsen; Frokjaer, Sven; Carpenter, John F; Brange, Jens

2002-12-01

Fibril formation (aggregation) of human and bovine insulin and six human insulin mutants in hydrochloric acid were investigated by visual inspection, Thioflavin T fluorescence spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The fibrillation tendencies of the wild-type insulins and the insulin mutants were (in order of decreasing fibrillation tendencies): Glu(B1) + Glu(B27) = bovine < human < des-(B1,B2)-insulin < Ser(B2) + Asp(B10) < Glu(A13) + Glu(B10) = Gln(B17) < Asp(B10). Transmission electron micrographs showed that the protofibrils of the mutants were similar to those of wild-type insulins and had a diameter of 5-10 nm and lengths varying from 50 nm to several microns. The fibrils of human insulin mutants exhibited varying degrees of lateral aggregation. The Asp(B10) mutant and human insulin had greater tendency to form laterally aggregated fibrils arranged in parallel bundles, whereas fibrils of the other mutants and bovine insulin were mainly arranged in helical filaments. FTIR spectroscopy showed that the native secondary structure of the wild-type insulins and the human insulin mutants in hydrochloric acid were identical, whereas the secondary structure of the fibrils formed by heating at 50 degrees C depended on the amino acid substitution. FTIR spectra of fibrils of the human insulin mutants exhibited different beta-sheet bands at 1,620-1,640 cm(-1), indicating that the beta-sheet interactions in the fibrils depended on variations in the primary structure of insulin. Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2473-2480, 2002

The actions of exogenous leucine on mTOR signalling and amino acid transporters in human myotubes

Directory of Open Access Journals (Sweden)

Cameron-Smith David

2011-06-01

Full Text Available Abstract Background The branched-chain amino acid (BCAA leucine has been identified to be a key regulator of skeletal muscle anabolism. Activation of anabolic signalling occurs via the mammalian target of rapamycin (mTOR through an undefined mechanism. System A and L solute carriers transport essential amino acids across plasma membranes; however it remains unknown whether an exogenous supply of leucine regulates their gene expression. The aim of the present study was to investigate the effects of acute and chronic leucine stimulation of anabolic signalling and specific amino acid transporters, using cultured primary human skeletal muscle cells. Results Human myotubes were treated with leucine, insulin or co-treated with leucine and insulin for 30 min, 3 h or 24 h. Activation of mTOR signalling kinases were examined, together with putative nutrient sensor human vacuolar protein sorting 34 (hVps34 and gene expression of selected amino acid transporters. Phosphorylation of mTOR and p70S6K was transiently increased following leucine exposure, independently to insulin. hVps34 protein expression was also significantly increased. However, genes encoding amino acid transporters were differentially regulated by insulin and not leucine. Conclusions mTOR signalling is transiently activated by leucine within human myotubes independently of insulin stimulation. While this occurred in the absence of changes in gene expression of amino acid transporters, protein expression of hVps34 increased.

A COMPARATIVE STUDY OF HUMAN PANCREAS WITH OTHER MAMMALIAN PANCREAS

Directory of Open Access Journals (Sweden)

Jyotsna Bhuyan

2016-09-01

Full Text Available Human pancreas is the largest digestive gland in the body. It has both endocrine and exocrine functions. Pancreas secretes the hormones insulin and glucagon. Insulin keeps the body in euglycaemic state as the main function of insulin is metabolism of carbohydrate. Diabetes is a disease of altered carbohydrate metabolism. At present, pancreatic transplantation is the only definitive therapy that can establish a euglycaemic state. AIM AND OBJECTIVE Keeping the importance of pancreatic hormones in human, the present study was carried out where we compared the pancreatic morphology of human with that of pig and goat in terms of length, breadth and weight. MATERIALS AND METHODS This study was conducted in the Department of Anatomy, Assam Medical College, Dibrugarh. A total of 90 specimens were included in the study and these were obtained from human, pig and goat. The human specimen (30 in number were collected from the Forensic Medicine Department of AMCH after fulfilling the official requirements. The specimen of pig and goat (30 each in number were collected from the local slaughter house after obtaining ethical clearance from the concerned authority. In all specimens, the length, breadth and weight was recorded with the help of measuring tape, vernier callipers and electronic weighing machine. INCLUSION AND EXCLUSION CRITERIA Specimen showing signs of putrefaction, any cut or crush injury and congenital anomalies were excluded from the study. RESULT AND OBSERVATIONS In human, the length of the pancreas ranged from 12.11 to 15.09 cm. Maximum breadth of the human pancreas ranged from 4.03 to 5.12 cm and the weight ranged from 79.13 to 102.22 gram. In goat, the length of the pancreas ranged from 12.43 to 13.79 cm, the breadth ranged from 3.03 to 4.93 cm and the weight ranged from 48.43 to 70.03 gram. In pig, the length of the pancreas ranged from 12.46 to 15.87 cm. Maximum breadth of pig pancreas ranged from 3.76 to 4.78 cm and the weight ranged

Switching from biphasic human insulin to biphasic insulin aspart 30 in type 2 diabetes: results from the ASEAN subgroup of the A₁chieve study.

Science.gov (United States)

Hussein, Zanariah; Lim-Abrahan, Mary Anne; Jain, Anand B; Goh, Su Yen; Soewondo, Pradana

2013-04-01

To evaluate the safety and effectiveness of biphasic insulin aspart 30 (BIAsp 30) in ASEAN type 2 diabetes (T2D) patients switched from biphasic human insulin (BHI) in the non-interventional 24-week A₁chieve study. Indonesian, Malaysian, Filipino and Singaporean patients switched from BHI to BIAsp 30 at their physicians' discretion were included. The incidence of serious adverse drug reactions (SADRs), including major hypoglycaemia was the primary endpoint. Changes in hypoglycaemia, glycated haemoglobin A1c (HbA1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPPG), lipids, body weight and systolic blood pressure were also evaluated. Quality of life (QoL) was measured using the EQ-5D questionnaire. For the 465 patients included (mean ± SD age: 56 ± 10.3 years, diabetes duration: 9.7 ± 7.1 years, baseline HbA1c: 9.4 ± 1.8%), the mean pre-study BHI dose was 0.62 ± 0.28 IU/kg and 63.4% were dosing BHI twice daily (bid). The mean baseline BIAsp 30 dose was 0.65 ± 0.27 U/kg, titrated up to 0.71 ± 0.28 U/kg over 24 weeks, and most patients continued bid dosing. No SADRs or major hypoglycaemic episodes were reported. The proportion of patients reporting overall hypoglycaemia decreased significantly from 10.8% at baseline to 3.4% at Week 24 (p ASEAN subgroup poorly controlled on BHI. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Insulin analogues and severe hypoglycaemia in type 1 diabetes

DEFF Research Database (Denmark)

Kristensen, P L; Hansen, L S; Jespersen, M J

2012-01-01

The effect of insulin analogues on glycaemic control is well-documented, whereas the effect on avoidance of severe hypoglycaemia remains tentative. We studied the frequency of severe hypoglycaemia in unselected patients with type 1 diabetes treated with insulin analogues, human insulin, or mixed...

Evaluating the evidence for macrophage presence in skeletal muscle and its relation to insulin resistance in obese mice and humans: a systematic review protocol.

Science.gov (United States)

Bhatt, Meha; Rudrapatna, Srikesh; Banfield, Laura; Bierbrier, Rachel; Wang, Pei-Wen; Wang, Kuan-Wen; Thabane, Lehana; Samaan, M Constantine

2017-08-08

The current global rates of obesity and type 2 diabetes are staggering. In order to implement effective management strategies, it is imperative to understand the mechanisms of obesity-induced insulin resistance and diabetes. Macrophage infiltration and inflammation of the adipose tissue in obesity is a well-established paradigm, yet the role of macrophages in muscle inflammation, insulin resistance and diabetes is not adequately studied. In this systematic review, we will examine the evidence for the presence of macrophages in skeletal muscle of obese humans and mice, and will assess the association between muscle macrophages and insulin resistance. We will identify published studies that address muscle macrophage content and phenotype, and its association with insulin resistance. We will search MEDLINE/PubMed, EMBASE, and Web of Science for eligible studies. Grey literature will be searched in ProQuest. Quality assessment will be conducted using the Systematic Review Centre for Laboratory Animal Experimentation risk of bias Tool for animal studies. The findings of this systematic review will shed light on immune-metabolic crosstalk in obesity, and allow the consideration of targeted therapies to modulate muscle macrophages in the treatment and prevention of diabetes. The review will be published in a peer-reviewed journal and presented at conferences.

Dnmt3a is an epigenetic mediator of adipose insulin resistance

DEFF Research Database (Denmark)

You, Dongjoo; Nilsson, Emma; Tenen, Danielle E.

2017-01-01

Insulin resistance results from an intricate interaction between genetic make-up and environment, and thus may be orchestrated by epigenetic mechanisms like DNA methylation. Here, we demonstrate that DNA methyltransferase 3a (Dnmt3a) is both necessary and sufficient to mediate insulin resistance...... in cultured mouse and human adipocytes. Furthermore, adipose-specific Dnmt3a knock-out mice are protected from diet-induced insulin resistance and glucose intolerance without accompanying changes in adiposity. Unbiased gene profiling studies revealed Fgf21 as a key negatively regulated Dnmt3a target gene...... in adipocytes with concordant changes in DNA methylation at the Fgf21 promoter region. Consistent with this, Fgf21 can rescue Dnmt3a-mediated insulin resistance, and DNA methylation at the FGF21 locus was elevated in human subjects with diabetes and correlated negatively with expression of FGF21 in human...

Insulin aspart pharmacokinetics

DEFF Research Database (Denmark)

Rasmussen, Christian Hove; Roge, Rikke Meldgaard; Ma, Zhulin

2014-01-01

Background: Insulin aspart (IAsp) is used by many diabetics as a meal-time insulin to control postprandial glucose levels. As is the case with many other insulin types, the pharmacokinetics (PK), and consequently the pharmacodynamics (PD), is associated with clinical variability, both between...... to investigate and quantify the properties of the subcutaneous depot. Data from Brange et al. (1990) are used to determine the effects of insulin chemistry in subcutis on the absorption rate. Intravenous (i.v.) bolus and infusion PK data for human insulin are used to understand and quantify the systemic...... distribution and elimination (Porksen et al., 1997; Sjostrand et al., 2002). PK and PD profiles for type 1 diabetics from Chen et al. (2005) are analyzed to demonstrate the effects of IAsp antibodies in terms of bound and unbound insulin. PK profiles from Thorisdottir et al. (2009) and Ma et al. (2012b...

Human embryonic stem cell derived islet progenitors mature inside an encapsulation device without evidence of increased biomass or cell escape.

Science.gov (United States)

Kirk, Kaitlyn; Hao, Ergeng; Lahmy, Reyhaneh; Itkin-Ansari, Pamela

2014-05-01

There are several challenges to successful implementation of a cell therapy for insulin dependent diabetes derived from human embryonic stem cells (hESC). Among these are development of functional insulin producing cells, a clinical delivery method that eliminates the need for chronic immunosuppression, and assurance that hESC derived tumors do not form in the patient. We and others have shown that encapsulation of cells in a bilaminar device (TheraCyte) provides immunoprotection in rodents and primates. Here we monitored human insulin secretion and employed bioluminescent imaging (BLI) to evaluate the maturation, growth, and containment of encapsulated islet progenitors derived from CyT49 hESC, transplanted into mice. Human insulin was detectable by 7 weeks post-transplant and increased 17-fold over the course of 8 weeks, yet during this period the biomass of encapsulated cells remained constant. Remarkably, by 20 weeks post-transplant encapsulated cells secreted sufficient levels of human insulin to ameliorate alloxan induced diabetes. Further, bioluminescent imaging revealed for the first time that hESCs remained fully contained in encapsulation devices for up to 150 days, the longest period tested. Collectively, the data suggest that encapsulated hESC derived islet progenitors hold great promise as an effective and safe cell replacement therapy for insulin dependent diabetes. Copyright © 2014. Published by Elsevier B.V.

PPAR2Pro12Ala Polymorphism and Human Health

Directory of Open Access Journals (Sweden)

Weimin He

2009-01-01

Full Text Available The nuclear hormone receptor peroxisome proliferator activated receptor gamma (PPAR is an important transcription factor regulating adipocyte differentiation, lipid and glucose homeostasis, and insulin sensitivity. Numerous genetic mutations of PPAR have been identified and these mutations positively or negatively regulate insulin sensitivity. Among these, a relatively common polymorphism of PPAR, Pro12Ala of PPAR2, the isoform expressed only in adipose tissue has been shown to be associated with lower body mass index, enhanced insulin sensitivity, and resistance to the risk of type 2 diabetes in human subjects carrying this mutation. Subsequent studies in different ethnic populations, however, have revealed conflicting results, suggesting a complex interaction between the PPAR2 Pro12Ala polymorphism and environmental factors such as the ratio of dietary unsaturated fatty acids to saturated fatty acids and/or between the PPAR2 Pro12Ala polymorphism and genetic factors such as polymorphic mutations in other genes. In addition, this polymorphic mutation in PPAR2 is associated with other aspects of human diseases, including cancers, polycystic ovary syndrome, Alzheimer disease and aging. This review will highlight findings from recent studies.

Familial hyperinsulinemia associated with secretion of an abnormal insulin, and coexistence of insulin resistance in the propositus.

Science.gov (United States)

Vinik, A I; Seino, S; Funakoshi, A; Schwartz, J; Matsumoto, M; Schteingart, D E; Fu, Z Z; Tsai, S T

1986-04-01

A 45-yr-old muscular nonobese white man who had a 9-yr history of syncopal episodes was studied on several occasions between April 1979 and August 1984. Fasting glucose concentrations ranged between 74-115 mg/dl, and those of insulin ranged between 14-64 microU/ml. Reactive hypoglycemia 3-4 h after ingestion of glucose occurred in the first 2 yr. Glucose tolerance was impaired in 1979, from February 1982 through September 1983, and again in August 1984. The maximum plasma insulin response to glucose ranged between 475-1630 microU/ml. When studied in November 1982, insulin (0.1 U/kg) caused a fall in blood glucose concentration of only 25% (normal, greater than 50%), and maximal glucose utilization during the euglycemic hyperinsulinemic clamp was 7.5 mg/kg . min (normal, greater than 12 mg/kg . min). Plasma counterregulatory hormone concentrations were normal, and antibodies to insulin and the insulin receptor were absent. Binding of exogenous insulin to the patient's cellular receptors (monocytes, red blood cells, and skin fibroblasts) was normal. Insulin was purified from plasma by immunoaffinity and molecular sieve chromatography and was found to elute later than human insulin on reversed phase high performance liquid chromatography. It was more hydrophobic than normal human insulin and had only 10% of the activity of normal insulin in terms of ability to bind to and stimulate glucose metabolism in isolated rat adipocytes. The abnormal insulin was identified in two of three sons and a sister, but not in the mother, brother, or niece. Sensitivity to insulin was normal in the two sons who had abnormal insulin. These results suggest that in this family the abnormal insulin was due to a biosynthetic defect, inherited as an autosomal dominant trait. The hyperinsulinemia was not associated with diabetes in family members who had no insulin resistance.

Insulin Resistance

DEFF Research Database (Denmark)

Jensen, Benjamin Anderschou Holbech

Insulin resistance (IR) is escalating with alarming pace and is no longer restricted to westernized countries. As a forerunner for some of the most serious threats to human health including metabolic syndrome, cardiovascular diseases, and type 2-diabetes, the need for new treatment modalities...... interventions. We further show that improving the inflammatory toning, using fish oil as fat source, protects mice against diet induced obesity and -inflammation while preserving insulin sensitivity, even in the absence of free fatty acid receptor 4. Conversely, HFD-induced intestinal dysbiosis is associated...

Sustained Brown Fat Stimulation and Insulin Sensitization by a Humanized Bispecific Antibody Agonist for Fibroblast Growth Factor Receptor 1/βKlotho Complex

Directory of Open Access Journals (Sweden)

Ganesh Kolumam

2015-07-01

Full Text Available Dissipating excess calories as heat through therapeutic stimulation of brown adipose tissues (BAT has been proposed as a potential treatment for obesity-linked disorders. Here, we describe the generation of a humanized effector-less bispecific antibody that activates fibroblast growth factor receptor (FGFR 1/βKlotho complex, a common receptor for FGF21 and FGF19. Using this molecule, we show that antibody-mediated activation of FGFR1/βKlotho complex in mice induces sustained energy expenditure in BAT, browning of white adipose tissue, weight loss, and improvements in obesity-associated metabolic derangements including insulin resistance, hyperglycemia, dyslipidemia and hepatosteatosis. In mice and cynomolgus monkeys, FGFR1/βKlotho activation increased serum high-molecular-weight adiponectin, which appears to contribute over time by enhancing the amplitude of the metabolic benefits. At the same time, insulin sensitization by FGFR1/βKlotho activation occurs even before the onset of weight loss in a manner that is independent of adiponectin. Together, selective activation of FGFR1/βKlotho complex with a long acting therapeutic antibody represents an attractive approach for the treatment of type 2 diabetes and other obesity-linked disorders through enhanced energy expenditure, insulin sensitization and induction of high-molecular-weight adiponectin.

Insulin-like growth factor II (IGF II) in human brain: regional distribution of IGF II and of higher molecular mass forms

International Nuclear Information System (INIS)

Haselbacher, G.K.; Schwab, M.E.; Pasi, A.; Humbel, R.E.

1985-01-01

Twenty-four distinct areas of human brain were analyzed for the presence of insulin-like growth factor (IGF). As reported for cerebrospinal fluid, only IGF II-like immunoreactivity, but no significant amounts of IGF I-like immunoreactivity, could be found. Upon gel permeation chromatography, two to five distinct size classes were separated on the basis of their immunoreactivity. Radioimmunoassays and a bioassay also gave results indistinguishable from those of serum IGF II. The highest amounts of IGF II-like immunoreactivity occur in the anterior pituitary. This is up to 100 times more than in most other brain regions analyzed. The higher molecular mass immunoreactive species were partially characterized. After immunoaffinity purification, the 38- and 26-kDa species are active in a bioassay. Specific IGF-binding protein activity could be shown after purification of the 38- and 26-kDa species on an IGF-affinity column. The 13-kDa species released significant amounts of 7.5-kDa material. The results are interpreted as evidence for the presence of IGF II synthesized locally in human brain