RNA m6A reader IMP2/IGF2BP2 promotes pancreatic ß-cell proliferation and insulin secretion by enhancing PDX1 expression.

BACKGROUND: Type 2 diabetes (T2D) is a common metabolic disease. Variants in human IGF2 mRNA binding protein 2 (IMP2/IGF2BP2) are associated with increased risk of T2D. IMP2 contributes to T2D susceptibility primarily through effects on insulin secretion. However, the underlying mechanism is not known. METHODS: To understand the role of IMP2 in insulin secretion and T2D pathophysiology, we generated Imp2 pancreatic ß-cell specific knockout mice (ßIMP2KO) by recombining the Imp2flox allele with Cre recombinase driven by the rat insulin 2 promoter. We further characterized metabolic phenotypes of ßIMP2KO mice and assessed their ß-cell functions. RESULTS: The deletion of IMP2 in pancreatic ß-cells leads to reduced compensatory ß-cell proliferation and function. Mechanically, IMP2 directly binds to Pdx1 mRNA and stimulates its translation in an m6A dependent manner. Moreover, IMP2 orchestrates IGF2-AKT-GSK3ß-PDX1 signaling to stable PDX1 polypeptides. In human EndoC-ßH1 cells, the over-expression of IMP2 is capable to enhance cell proliferation, PDX1 protein level and insulin secretion. CONCLUSION: Our work therefore reveals IMP2 as a critical regulator of pancreatic ß-cell proliferation and function; highlights the importance of posttranscriptional gene expression in T2D pathology.

A Novel Dual-Hormone Insulin-and-Pramlintide Artificial Pancreas for Type 1 Diabetes: A Randomized Controlled Crossover Trial.

OBJECTIVE: The rapid insulin-alone artificial pancreas improves glycemia in type 1 diabetes but daytime control remains suboptimal. We propose two novel dual-hormone artificial pancreas systems. RESEARCH DESIGN AND METHODS: We conducted a randomized crossover trial comparing a rapid insulin-alone artificial pancreas with rapid insulin-and-pramlintide and with regular insulin-and-pramlintide artificial pancreas systems in adults with type 1 diabetes. Participants were assigned to the interventions in random order during three 24-h inpatient visits. Each visit was preceded by an outpatient hormonal open-loop run-in period of 10-14 days. The dual-hormone artificial pancreas delivered pramlintide in a basal-bolus manner, using a novel dosing algorithm, with a fixed ratio relative to insulin. The primary outcome was time in the range 3.9-10.0 mmol/L. RESULTS: Compared with the rapid insulin-alone artificial pancreas system, the rapid insulin-and-pramlintide system increased the time in range from 74% (SD 18%) to 84% (13%) (P = 0.0014), whereas the regular insulin-and-pramlintide system did not change the time in range (69% [19%]; P = 0.22). The increased time in range with the rapid insulin-and-pramlintide system was due to improved daytime control (daytime time in range increased from 63% [23%] to 78% [16%], P = 0.0004). There were 11 (1 per 2.5 days) hypoglycemic events (<3.3 mmol/L with symptoms or <3.0 mmol/L irrespective of symptoms) with the rapid insulin-alone system, compared with 12 (1 per 2.3 days) and 18 (1 per 1.4 days) with the rapid and regular insulin-and-pramlintide systems, respectively. Gastrointestinal symptoms were reported after 0% (0 of 112) of meals with the rapid insulin-alone system, compared with 6% (6 of 108) and 11% (11 of 104) with the rapid and regular insulin-and-pramlintide systems, respectively; none of the symptoms were severe. CONCLUSIONS: A novel rapid insulin-and-pramlintide artificial pancreas improves glucose control compared with a rapid insulin-alone artificial pancreas (ClinicalTrials.gov number NCT02814123).

Determinants of longitudinal change in insulin clearance: the Prospective Metabolism and Islet Cell Evaluation cohort.

Objective: To evaluate multiple determinants of the longitudinal change in insulin clearance (IC) in subjects at high risk for type 2 diabetes (T2D). Research design and methods: Adults (n=492) at risk for T2D in the Prospective Metabolism and Islet Cell Evaluation cohort, a longitudinal observational cohort, had four visits over 9 years. Values from oral glucose tolerance tests collected at each assessment were used to calculate the ratios of both fasting C peptide-to-insulin (ICFASTING) and areas under the curve of C peptide-to-insulin (ICAUC). Generalized estimating equations (GEE) evaluated multiple determinants of longitudinal changes in IC. Results: IC declined by 20% over the 9-year follow-up period (p<0.05). Primary GEE results indicated that non-European ethnicity, as well as increases in baseline measures of waist circumference, white cell count, and alanine aminotransferase, was associated with declines in ICFASTING and ICAUC over time (all p<0.05). There were no significant associations of IC with sex, age, physical activity, smoking, or family history of T2D. Both baseline and longitudinal IC were associated with incident dysglycemia. Conclusions: Our findings suggest that non-European ethnicity and components of the metabolic syndrome, including central obesity, non-alcoholic fatty liver disease, and subclinical inflammation, may be related to longitudinal declines in IC.

Control of Postprandial Hyperglycemia in Type 1 Diabetes by 24-Hour Fixed-Dose Coadministration of Pramlintide and Regular Human Insulin: A Randomized, Two-Way Crossover Study.

OBJECTIVE: Healthy pancreatic ß-cells secrete the hormones insulin and amylin in a fixed ratio. Both hormones are lacking in type 1 diabetes, and postprandial glucose control using insulin therapy alone is difficult. This study tested the pharmacodynamic effects of the amylin analog pramlintide and insulin delivered in a fixed ratio over a 24-h period. RESEARCH DESIGN AND METHODS: Patients with type 1 diabetes were stabilized on insulin pump therapy with insulin lispro before a randomized, single-masked, two-way crossover, 24-h inpatient study in which regular human insulin was administered with pramlintide or placebo using separate infusion pumps in a fixed ratio (9 µg/unit). Meal content and timing and patient-specific insulin doses were the same with each treatment. The primary outcome measure was change in mean glucose by continuous glucose monitoring (CGM). Profiles of laboratory-measured glucose, insulin, glucagon, and triglycerides were also compared. RESULTS: Mean 24-h glucose measured by CGM was lower with pramlintide versus placebo (8.5 vs. 9.7 mmol/L, respectively; P = 0.012) due to a marked reduction of postprandial increments. Glycemic variability was reduced, and postprandial glucagon and triglycerides were also lower with pramlintide versus placebo. Gastrointestinal side effects were more frequent during use of pramlintide; no major hypoglycemic events occurred with pramlintide or placebo. CONCLUSIONS: Coadministration of fixed-ratio pramlintide and regular human insulin for 24 h improved postprandial hyperglycemia and glycemic variability in patients with type 1 diabetes. Longer studies including dose titration under daily conditions are needed to determine whether this regimen could provide long-term improvement of glycemic control.

Caneta para injeção de insulina humana NPH e insulina humana regular / Pen for injection of human insulin NPH and regular human insulin

CONTEXTO: Atualmente, o SUS disponibiliza as insulinas humanas NPH 100 UI/ml e regular 100 UI/ml e, para sua aplicação, seringas com agulhas acopladas. Não são disponibilizadas canetas para aplicação do medicamento. TECNOLOGIA: Caneta para injeção de insulina. INDICAÇÃO: Aplicação de insulina para tratamento de Diabetes Mellitus. EVIDÊNCIAS CIENTÍFICAS: Vários estudos que comparam as formas de administração de insulina mostram perfis mais favoráveis com o uso da caneta, quando comparada à seringa, em relação aos parâmetros de preferência, adesão ao tratamento, facilidade de uso, conveniência, manuseio e ajuste de dosagem. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: Foi estimado um impacto orçamentário no SUS de aproximadamente 53 milhões em um ano e de 107 milhões em três anos, com a incorporação das canetas de aplicação de insulina para todos os pacientes diabéticos brasileiros. RECOMENDAÇÃO DA CONITEC: Os membros do plenário da CONITEC recomendaram a incorporação da caneta para injeção de insulina no SUS na 52ª reunião da CONITEC, em 1° e 2 de fevereiro de 2017. DECISÃO: Incorporar caneta para injeção de insulina humana NPH e insulina humana regular, no âmbito do Sistema Único de Saúde - SUS. A decisão foi dada pela Portaria SCTIE-MS nº 11 publicada no Diário Oficial da União (DOU) nº 50, de 14 de março de 2017, pág. 53.(AU)

Comparison of Basal-Bolus and Premixed Insulin Regimens in Hospitalized Patients With Type 2 Diabetes.

OBJECTIVE: Premixed insulin is a commonly prescribed formulation for the outpatient management of patients with type 2 diabetes. The safety and efficacy of premixed insulin formulations in the hospital setting is not known. RESEARCH DESIGN AND METHODS: In a prospective, open-label trial, we randomized general medicine and surgery patients to receive a basal-bolus regimen with glargine once daily and glulisine before meals (n = 33) or premixed human insulin (30% regular insulin and 70% NPH insulin) twice daily (n = 39). Major outcomes included differences in daily blood glucose (BG) levels and frequency of hypoglycemic events (<70 mg/dL) between treatment groups. RESULTS: At the first prespecified interim analysis, the study was stopped early because of an increased frequency of hypoglycemia >50% in patients treated with premixed human insulin. A total of 64% of patients treated with premixed insulin experienced one or more episodes of hypoglycemia compared with 24% in the basal-bolus group (P < 0.001). There were no differences in mean daily BG level after the first day of insulin treatment (175 ± 32 vs. 179 ± 43 mg/dL, P = 0.64) between groups. A BG target between 80 and 180 mg/dL before meals was achieved in 55.9% of BG readings in the basal-bolus group and 54.3% of BG readings in the premixed insulin group (P = 0.23). There was no difference in the length of hospital stay or mortality between treatment groups. CONCLUSIONS: Inpatient treatment with premixed human insulin resulted in similar glycemic control but in significantly higher frequency of hypoglycemia compared with treatment with basal-bolus insulin regimen in hospitalized patients with diabetes.

Enhanced insulin action following subcutaneous co-administration of insulin and C-peptide in rats.

BACKGROUND: This study was undertaken to examine if C-peptide (C) may interact with hexameric insulin and facilitate its disaggregation into the physiologically active monomeric form. METHODS: Regular insulin (I) or an insulin analogue (IA) were injected s.c. in rats together with C or its C-terminal pentapeptide (PP). I or IA and C or PP were administered either as a physical mixture or into two separate s.c. depots. Whole body glucose utilization was evaluated using the euglycemic clamp technique. Phosphorylation of Akt/PKB and GSK in liver and skeletal muscles and 86Rb⁺ uptake by L6 cells were measured. RESULTS: S.c. injection of a mixture of I and C or I and PP resulted in a 30-55% greater (P < 0.01-0.001) and 15-27% (P < 0.05-0.001) longer stimulation of whole body glucose utilization than after separate injections. Insulin-stimulated phosphorylation of Akt/PKB in liver increased 35% more after injection of I and C in mixture compared with after separate injections. Phosphorylation of GSK3 was augmented by 50% (P < 0.05) following the injection of I and C in mixture compared with separate injections. Stimulation of myotubes with premixed I and C (1 nM) elicited 20% additional increase in ouabain-sensitive 86Rb⁺ uptake (P < 0.05) in comparison with the effect when I and C were added separately. CONCLUSIONS: Subcutaneous co-administration of insulin and C results in augmented insulin bioactivity at the level of tissue glucose uptake, intracellular signalling, and enzyme activation. These effects may be attributed to augmented C mediated disaggregation of hexameric insulin into its physiologically active monomeric form.

Long-acting insulins alter milk composition and metabolism of lactating dairy cows.

This study investigated the effect of 2 different types of long-acting insulin on milk production, milk composition, and metabolism in lactating dairy cows. Multiparous cows (n=30) averaging 88 d in milk were assigned to one of 3 treatments in a completely randomized design. Treatments consisted of control (C), Humulin-N (H; Eli Lilly and Company, Indianapolis, IN), and insulin glargine (L). The H and L treatments were administered twice daily at 12-h intervals via subcutaneous injection for 10d. Cows were milked twice daily, and milk composition was determined every other day. Mammary biopsies were conducted on d 11, and mammary proteins extracted from the biopsies were analyzed by Western blot for components of insulin and mammalian target of rapamycin signaling pathways. Treatment had no effect on dry matter intake or milk yield. Treatment with both forms of long-acting insulin increased milk protein content and tended to increase milk protein yield over the 10-d treatment period. Analysis of milk N fractions from samples collected on d 10 of treatment suggested that cows administered L tended to have higher yields of milk protein fractions than cows administered H. Milk fat content and yield tended to be increased for cows administered long-acting insulins. Lactose content and yields were decreased by treatment with long-acting insulins. Administration of long-acting insulins, particularly L, tended to shift milk fatty acid composition toward increased short- and medium-chain fatty acids and decreased long-chain fatty acids. Plasma concentrations of glucose and urea N were lower for cows administered long-acting insulins; interactions of treatment and sampling time were indicative of more pronounced effects of L than H on these metabolites. Concentrations of nonesterified fatty acids and insulin were increased in cows administered long-acting insulins. Decreased concentrations of urea N in both plasma and milk suggested more efficient use of N in cows administered long-acting insulins. Western blot analysis of mammary tissue collected by biopsy indicated that the ratios of phosphorylated protein kinase b (Akt) to total Akt and phosphorylated ribosomal protein S6 (rpS6) to total rpS6 were not affected by long-acting insulins. Modestly elevating insulin activity in lactating dairy cows using long-acting insulins altered milk composition and metabolism. Future research should explore mechanisms by which either insulin concentrations or insulin signaling pathways in the mammary gland can be altered to enhance milk fat and protein production.

Management of hyperglycemia in diabetic patients with hematologic malignancies during dexamethasone therapy.

OBJECTIVE: To compare the response to different insulin regimens for management of hyperglycemia in diabetic patients with hematologic malignancies who are receiving dexamethasone. METHODS: A retrospective analysis was conducted to determine whether a basal bolus insulin (BBI) regimen with detemir and aspart is superior to a sliding scale regular insulin (SSI) regimen for management of hyperglycemia in hospitalized diabetic patients receiving dexamethasone. RESULTS: Forty patients with hematologic malignancies were treated with intravenous (8 to 12 mg/day) or oral (40 mg/day) dexamethasone for 3 days. The average blood glucose (BG) level was 301 ± 57 mg/dL in the SSI group (n = 28) and 219 ± 51 mg/dL in the BBI group (n = 12) (P <.001). The BBI regimen resulted in an average BG reduction of 52 ± 82 mg/dL throughout the course of dexamethasone therapy, while the SSI regimen produced an increase in the mean daily BG level of 128 ± 77 mg/dL (P <.001). On the last day of dexamethasone administration, the insulin requirement was 49 ± 29 units/day in the SSI group and 122 ± 39 units/day in the BBI group (P <.001). Three patients in the SSI group developed diabetic ketoacidosis or hyperosmolar hyperglycemia during steroid therapy. No hypoglycemia was observed in either group. The length of stay and infection rates were similar between groups. CONCLUSION: Basal and bolus insulin regimen is an effective and safe approach for managing dexamethasone-induced hyperglycemia in hospitalized patients with hematologic malignancies.

Randomized clinical trial of the impact of insulin therapy on liver function in patients undergoing major liver resection.

BACKGROUND: Postoperative liver dysfunction is the major source of morbidity and mortality in patients undergoing partial hepatectomy. This study tested the benefits of a metabolic support protocol based on insulin infusion, for reducing liver dysfunction following hepatic resection. METHODS: Consecutive consenting patients scheduled for liver resection were randomized to receive preoperative dextrose infusion followed by insulin therapy using the hyperinsulinaemic normoglycaemic clamp protocol (n = 29) or standard therapy (control group, n = 27). Patients in the insulin therapy group followed a strict dietary regimen for 24 h before surgery. Intravenous dextrose was started at 2 mg per kg per min the night before and continued until surgery. Hyperinsulinaemic therapy for a total of 24 h was initiated at 2 munits per kg per min at induction of anaesthesia, and continued at 1 munit per kg per min after surgery. Normoglycaemia was maintained (3.5-6.0 mmol/l). Control subjects received no additional dietary supplement and a conventional insulin sliding scale during fasting. All patients were tested serially to evaluate liver function using the Schindl score. Liver tissue samples were collected at two time points during surgery to measure glycogen levels. RESULTS: Demographics were similar in the two groups. More liver dysfunction occurred in the control cohort (liver dysfunction score range 0-8 versus 0-4 with insulin therapy; P = 0.031). Median (interquartile range) liver glycogen content was 278 (153-312) and 431 (334-459) µmol/g respectively (P = 0.011). The number of complications rose with increasing severity of postoperative liver dysfunction (P = 0.032) CONCLUSION: The glucose-insulin protocol reduced postoperative liver dysfunction and improved liver glycogen content. REGISTRATION NUMBER: NCT00774098 (http://www.clinicaltrials.gov).

Insulin fails to enhance mTOR phosphorylation, mitochondrial protein synthesis, and ATP production in human skeletal muscle without amino acid replacement.

Systemic insulin administration causes hypoaminoacidemia by inhibiting protein degradation, which may in turn inhibit muscle protein synthesis (PS). Insulin enhances muscle mitochondrial PS and ATP production when hypoaminoacidemia is prevented by exogenous amino acid (AA) replacement. We determined whether insulin would stimulate mitochondrial PS and ATP production in the absence of AA replacement. Using l-[1,2-¹³C]leucine as a tracer, we measured the fractional synthetic rate of mitochondrial as well as sarcoplasmic and mixed muscle proteins in 18 participants during sustained (7-h) insulin or saline infusion (n = 9 each). We also measured muscle ATP production, mitochondrial enzyme activities, mRNA levels of mitochondrial genes, and phosphorylation of signaling proteins regulating protein synthesis. The concentration of circulating essential AA decreased during insulin infusion. Mitochondrial, sarcoplasmic, and mixed muscle PS rates were also lower during insulin (2-7 h) than during saline infusions despite increased mRNA levels of selected mitochondrial genes. Under these conditions, insulin did not alter mitochondrial enzyme activities and ATP production. These effects were associated with enhanced phosphorylation of Akt but not of protein synthesis activators mTOR, p70(S6K), and 4EBP1. In conclusion, sustained physiological hyperinsulinemia without AA replacement did not stimulate PS of mixed muscle or protein subfractions and did not alter muscle mitochondrial ATP production in healthy humans. These results support that insulin and AA act in conjunction to stimulate muscle mitochondrial function and mitochondrial protein synthesis.

Risk of cancer in patients on insulin glargine and other insulin analogues in comparison with those on human insulin: results from a large population-based follow-up study.

AIMS/HYPOTHESIS: Several publications suggest an association between certain types of insulin and cancer, but with conflicting results. We investigated whether insulin glargine (A21Gly,B31Arg,B32Arg human insulin) is associated with an increased risk of cancer in a large population-based cohort study. METHODS: Data for this study were obtained from dispensing records from community pharmacies individually linked to hospital discharge records from 2.5 million individuals in the Netherlands. In a cohort of incident users of insulin, the association between insulin glargine and other insulin analogues, respectively, and cancer was analysed in comparison with human insulin using Cox proportional hazard models with cumulative duration of drug use as a time-varying determinant. The first hospital admission with a primary diagnosis of cancer was considered as the main outcome; secondary analyses were performed with specific cancers as outcomes. RESULTS: Of the 19,337 incident insulin users enrolled, 878 developed cancer. Use of insulin glargine was associated with a lower risk of malignancies in general in comparison with human insulin (HR 0.75, 95% CI 0.71, 0.80). In contrast, an increased risk was found for breast cancer (HR 1.58, 95% CI 1.22, 2.05). Dose-response relationships could not be identified. CONCLUSION/INTERPRETATION: Users of insulin glargine and users of other insulin analogues had a lower risk of cancer in general than those using human insulin. Both associations might be a consequence of residual confounding, lack of adherence or competing risk. However, as in previous studies, we demonstrated an increased risk of breast cancer in users of insulin glargine in comparison with users of human insulin.

[Oral administration of insulin inhibits islet beta cell apoptosis and prevents diabetes in NOD mice].

OBJECTIVE: To investigate the effect of oral administration of insulin on insulitis beta cell apoptosis and diabetes in non-obese diabetic (NOD) mice, and to explore the mechanism of immune tolerance induced by insulin. METHODS: Eighty-six female NOD mice were randomly divided into an insulin group (n=43) and a phosphate buffered saline (PBS) group (n=43). From 4 weeks of age, the recombinant human insulin (Humulin R) 1 mg (70 microL) was administrated in the oral insulin group and 70 microL PBS in the control group respectively, twice per week before 12 weeks of age and then once weekly until 30 weeks. Insulitis and beta cell apoptosis of islets were observed at 12 weeks. IL-4 and IFN-gamma in the sera were measured by enzyme linked immunosorbent assay (ELISA). The expression levels of I-Abeta(g7), IL-4, IFN-gamma, IL-1beta, Fas and TGF-beta mRNA of islets, and IL-4, IFN-gamma, TGF-beta mRNA of Peyer's patch were measured by reverse transcription-polymerase chain reaction (RT-PCR) at 12 weeks. RESULTS: The incidences in the insulin group were significantly lower than those in the PBS group (55.6% vs 85.7% at 30 weeks, 70.4% vs 96.4% at 52 weeks, P<0.05). The insulitis scores in the insulin group were lower than those in the PBS group, but there was no statistical significance. Fas expression on islets and apoptotic beta cell rates in the insulin group were lower than those in the PBS group (P<0.05). In the insulin group, serum IL-4 levels were higher, and IFN-gamma levels were lower than those in the PBS group (P<0.05). The levels of I-Abeta(g7), IFN-gamma, IL-1beta and Fas mRNA transcription in islets and IFN-gamma mRNA transcription in Peyer's patch were both lower in the insulin group, and IL-4, TGF-beta mRNA levels were higher than those in the PBS group (P<0.05). CONCLUSION: The specific autoantigen insulin may induce the immune tolerance and prevent the diabetes in NOD mice, but it cannot block the progression of insulitis. Oral administration of insulin can induce the regulatory T cells, and make Th1 to Th2 cytokine shifts in the system and islets, thus preventing the Fas-mediated beta-cell apoptosis and diabetes.