Effects of 18-months metformin versus placebo in combination with three insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes: A post-hoc analysis of a randomized clinical trial.

Formation of reactive oxygen species has been linked to the development of diabetes complications. Treatment with metformin has been associated with a lower risk of developing diabetes complications, including when used in combination with insulin. Metformin inhibits Complex 1 in isolated mitochondria and thereby decreases the formation of reactive oxygen species. Thus, we post-hoc investigated the effect of metformin in combination with different insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes. Four hundred and fifteen individuals with type 2 diabetes were randomized (1:1) to blinded treatment with metformin (1,000 mg twice daily) versus placebo and to (1:1:1) open-label biphasic insulin, basal-bolus insulin, or basal insulin therapy in a 2 × 3 factorial design. RNA and DNA oxidation were determined at baseline and after 18 months measured as urinary excretions of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), respectively. Urinary excretion of 8-oxoGuo changed by +7.1% (95% CI: 0.5% to 14.0%, P = 0.03) following metformin versus placebo, whereas changes in 8-oxodG were comparable between intervention groups. Biphasic insulin decreased urinary excretion of 8-oxoGuo (within-group: -9.6% (95% CI: -14.4% to -4.4%)) more than basal-bolus insulin (within-group: 5.2% (95% CI: -0.5% to 11.2%)), P = 0.0002 between groups, and basal insulin (within-group: 3.7% (95% CI: -2.0% to 9.7%)), P = 0.0007 between groups. Urinary excretion of 8-oxodG decreased more in the biphasic insulin group (within-group: -9.9% (95% CI: -14.4% to -5.2%)) than basal-bolus insulin (within group effect: -1.2% (95% CI: -6.1% to 3.9%)), P = 0.01 between groups, whereas no difference was observed compared with basal insulin. In conclusion, eighteen months of metformin treatment in addition to different insulin regimens increased RNA oxidation, but not DNA oxidation. Biphasic insulin decreased both RNA and DNA oxidation compared with other insulin regimens.

Prediction of carotid intima-media thickness and its relation to cardiovascular events in persons with type 2 diabetes.

AIMS: To investigate measures of carotid intima-media thickness (IMT) and conventional cardiovascular (CV) risk factors as predictors of future carotid IMT, and the prediction of CV events during follow-up based on measures of carotid IMT. METHODS: Observational longitudinal study including 230 persons with type 2 diabetes (T2D). RESULTS: Mean age at follow-up was 66.7 (SD 8.5) years, 30.5% were women and mean body mass index (BMI) was 31.8 (4.4) kg/m2. Carotid IMT was measured at baseline, after 18 months of intervention in the Copenhagen Insulin and Metformin Therapy (CIMT) trial and after a mean follow-up of 6.4 (1.0) years. Baseline carotid IMT, carotid IMT after 18 months' intervention, and CV risk factors (age, sex and baseline systolic blood pressure) gave the best prediction of carotid IMT (root mean-squared error of prediction of 0.106 and 95% prediction error probability interval of -0.160, 0.204). CONCLUSIONS: Measures of carotid IMT combined with CV risk factors at baseline predicts attained carotid IMT better than measures of carotid IMT or CV risk factors alone. Carotid IMT did not predict CV events, and the present results do not support the use of carotid IMT as a predictor of CV events in persons with T2D.

Effect of Metformin vs. Placebo in Combination with Insulin Analogues on Bone Markers P1NP and CTX in Patients with Type 2 Diabetes Mellitus.

Preclinical studies have shown a potential osteoanabolic effect of metformin but human studies of how metformin affects bone turnover are few. A post hoc sub-study analysis of an 18-month multicenter, placebo-controlled, double-blinded trial in type 2 diabetes mellitus (T2DM), randomizing participants to metformin versus placebo both in combination with different insulin analogue regimens (Metformin + Insulin vs. Placebo + Insulin). Patients were not treatment naive at baseline, 83% had received metformin, 69% had received insulin, 57.5% had received the combination of metformin and insulin before entering the study. Bone formation and resorption were assessed by measuring, N-terminal propeptide of type I procollagen (P1NP) and C-terminal telopeptide of type I collagen (CTX) at baseline and end of study. The influence of gender, age, smoking, body mass index (BMI), T2DM duration, glycosylated hemoglobin A1c (HbA1c), c-reactive protein (CRP) and insulin dosage was also included in the analyses. The levels of bone formation marker P1NP and bone resorption marker CTX increased significantly in both groups during the trial. P1NP increased less in the Metformin + Insulin compared to the placebo + insulin group (p = 0.001) (between group difference change), while the increases in CTX levels (p = 0.11) were not different. CRP was inversely associated (p = 0.012) and insulin dosage (p = 0.011) was positively related with change in P1NP levels. BMI (p = 0.002) and HbA1C (p = 0.037) were inversely associated with change in CTX levels. During 18 months of treatment with metformin or placebo, both in combination with insulin, bone turnover increased in both groups. But the pattern was different as the bone formation marker (P1NP) increased less during Metformin + Insulin treatment, while change in bone resorption (CTX) was not significantly different between the two groups.

ADAMTS9 Regulates Skeletal Muscle Insulin Sensitivity Through Extracellular Matrix Alterations.

The ADAMTS9 rs4607103 C allele is one of the few gene variants proposed to increase the risk of type 2 diabetes through an impairment of insulin sensitivity. We show that the variant is associated with increased expression of the secreted ADAMTS9 and decreased insulin sensitivity and signaling in human skeletal muscle. In line with this, mice lacking Adamts9 selectively in skeletal muscle have improved insulin sensitivity. The molecular link between ADAMTS9 and insulin signaling was characterized further in a model where ADAMTS9 was overexpressed in skeletal muscle. This selective overexpression resulted in decreased insulin signaling presumably mediated through alterations of the integrin ß1 signaling pathway and disruption of the intracellular cytoskeletal organization. Furthermore, this led to impaired mitochondrial function in mouse muscle-an observation found to be of translational character because humans carrying the ADAMTS9 risk allele have decreased expression of mitochondrial markers. Finally, we found that the link between ADAMTS9 overexpression and impaired insulin signaling could be due to accumulation of harmful lipid intermediates. Our findings contribute to the understanding of the molecular mechanisms underlying insulin resistance and type 2 diabetes and point to inhibition of ADAMTS9 as a potential novel mode of treating insulin resistance.

Efficacy and Safety of IDegLira in Participants with Type 2 Diabetes in India Uncontrolled on Oral Antidiabetic Drugs and Basal Insulin: Data from the DUAL Clinical Trial Program.

INTRODUCTION: The efficacy and safety of insulin degludec/liraglutide (IDegLira) has been evaluated in the Dual Action of Liraglutide and Insulin Degludec in Type 2 Diabetes (DUAL) phase 3 clinical trial program. In this post hoc analysis, we compared the efficacy and safety of IDegLira in the Indian subpopulation with the results from the global trial population of DUAL trials. The analysis includes participants uncontrolled on oral antidiabetic drugs (OADs) in DUAL I and DUAL IV and participants uncontrolled on basal insulin and OADs in DUAL II. METHODS: Three phase 3 trials were included in the analysis: DUAL I extension (IDegLira vs. insulin degludec or liraglutide 1.8 mg in participants uncontrolled on metformin ± pioglitazone; 52 weeks; n = 1663), DUAL IV (IDegLira vs. placebo as an add-on to a regimen of sulfonylurea ± metformin; 26 weeks; n = 435) and DUAL II (IDegLira vs. insulin degludec in participants uncontrolled on basal insulin + OADs; 26 weeks; n = 398). There were 251, 64 and 64 participants, respectively, at the Indian sites. RESULTS: In the Indian subpopulations, the reductions in glycated hemoglobin (HbA1c) with IDegLira were substantial [DUAL I: 1.96% (-21 mmol/mol); DUAL IV: -1.40% (-15 mmol/mol); DUAL II: -2.20% (-24 mmol/mol)] and significantly greater than those in the comparators in each trial. IDegLira was generally weight-neutral after the administration of OADs (-0.3 and +0.6 kg in DUAL I and DUAL IV) and resulted in weight loss after the administration of basal insulin (-2.1 kg in DUAL II). Hypoglycemia rates were 1.98, 1.08 and 0.37 events/patient-years of exposure (PYE) for IDegLira, insulin degludec and liraglutide in DUAL I, 4.06 and 0.36 events/PYE for IDegLira and placebo in DUAL IV and 1.16 and 0.83 events/PYE with IDegLira and insulin degludec in DUAL II. CONCLUSIONS: Results from the Indian subpopulations reflect those of the global study populations, supporting IDegLira as an effective and safe treatment option for people with type 2 diabetes inadequately controlled on OADs or basal insulin + OADs in the South Asian population. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01336023 (DUAL I), NCT01392573 (DUAL II), NCT01618162 (DUAL IV). FUNDING: Novo Nordisk A/S, Bagsvaerd, Denmark.

Effect of liraglutide, a glucagon-like peptide-1 analogue, on left ventricular function in stable chronic heart failure patients with and without diabetes (LIVE)-a multicentre, double-blind, randomised, placebo-controlled trial.

AIMS: To determine the effect of the glucagon-like peptide-1 analogue liraglutide on left ventricular function in chronic heart failure patients with and without type 2 diabetes. METHODS AND RESULTS: LIVE was an investigator-initiated, randomised, double-blinded, placebo-controlled multicentre trial. Patients (n = 241) with reduced left ventricular ejection fraction (LVEF ≤45%) were recruited (February 2012 to August 2015). Patients were clinically stable and on optimal heart failure treatment. Intervention was liraglutide 1.8 mg once daily or matching placebo for 24 weeks. The LVEF was similar at baseline in the liraglutide and the placebo group (33.7 ± 7.6% vs. 35.4 ± 9.4%). Change in LVEF did not differ between the liraglutide and the placebo group; mean difference (95% confidence interval) was -0.8% (-2.1, 0.5; P = 0.24). Heart rate increased with liraglutide [mean difference: 7 b.p.m. (5, 9), P < 0.0001]. Serious cardiac events were seen in 12 (10%) patients treated with liraglutide compared with 3 (3%) patients in the placebo group (P = 0.04). CONCLUSION: Liraglutide did not affect left ventricular systolic function compared with placebo in stable chronic heart failure patients with and without diabetes. Treatment with liraglutide was associated with an increase in heart rate and more serious cardiac adverse events, and this raises some concern with respect to the use of liraglutide in patients with chronic heart failure and reduced left ventricular function. More data on the safety of liraglutide in different subgroups of heart failure patients are needed.

Metformin versus placebo in combination with insulin analogues in patients with type 2 diabetes mellitus-the randomised, blinded Copenhagen Insulin and Metformin Therapy (CIMT) trial.

OBJECTIVE: To assess the effect of metformin versus placebo both in combination with insulin analogue treatment on changes in carotid intima-media thickness (IMT) in patients with type 2 diabetes. DESIGN AND SETTING: Investigator-initiated, randomised, placebo-controlled trial with a 2 × 3 factorial design conducted at eight hospitals in Denmark. PARTICIPANTS AND INTERVENTIONS: 412 participants with type 2 diabetes (glycated haemoglobin (HbA1c) ≥ 7.5% (≥ 58 mmol/mol); body mass index >25 kg/m2) were in addition to open-labelled insulin treatment randomly assigned 1:1 to 18 months blinded metformin (1 g twice daily) versus placebo, aiming at an HbA1c ≤ 7.0% (≤ 53 mmol/mol). OUTCOMES: The primary outcome was change in the mean carotid IMT (a marker of subclinical cardiovascular disease). HbA1c, insulin dose, weight and hypoglycaemic and serious adverse events were other prespecified outcomes. RESULTS: Change in the mean carotid IMT did not differ significantly between the groups (between-group difference 0.012 mm (95% CI -0.003 to 0.026), p=0.11). HbA1c was more reduced in the metformin group (between-group difference -0.42% (95% CI -0.62% to -0.23%), p<0.001)), despite the significantly lower insulin dose at end of trial in the metformin group (1.04 IU/kg (95% CI 0.94 to 1.15)) compared with placebo (1.36 IU/kg (95% CI 1.23 to 1.51), p<0.001). The metformin group gained less weight (between-group difference -2.6 kg (95% CI -3.3 to -1.8), p<0.001). The groups did not differ with regard to number of patients with severe or non-severe hypoglycaemic or other serious adverse events, but the metformin group had more non-severe hypoglycaemic episodes (4347 vs 3161, p<0.001). CONCLUSIONS: Metformin in combination with insulin did not reduce carotid IMT despite larger reduction in HbA1c, less weight gain, and smaller insulin dose compared with placebo plus insulin. However, the trial only reached 46% of the planned sample size and lack of power may therefore have affected our results. TRIAL REGISTRATION NUMBER: NCT00657943; Results.

Effects of biphasic, basal-bolus or basal insulin analogue treatments on carotid intima-media thickness in patients with type 2 diabetes mellitus: the randomised Copenhagen Insulin and Metformin Therapy (CIMT) trial.

OBJECTIVE: To assess the effect of 3 insulin analogue regimens on change in carotid intima-media thickness (IMT) in patients with type 2 diabetes. DESIGN AND SETTING: Investigator-initiated, randomised, placebo-controlled trial with a 2 × 3 factorial design, conducted at 8 hospitals in Denmark. PARTICIPANTS AND INTERVENTIONS: Participants with type 2 diabetes (glycated haemoglobin (HbA1c) ≥ 7.5% (≥ 58 mmol/mol), body mass index >25 kg/m(2)) were, in addition to metformin versus placebo, randomised to 18 months open-label biphasic insulin aspart 1-3 times daily (n=137) versus insulin aspart 3 times daily in combination with insulin detemir once daily (n=138) versus insulin detemir alone once daily (n=137), aiming at HbA1c ≤ 7.0% (≤ 53 mmol/mol). OUTCOMES: Primary outcome was change in mean carotid IMT (a marker of subclinical cardiovascular disease). HbA1c, insulin dose, weight, and hypoglycaemic and serious adverse events were other prespecified outcomes. RESULTS: Carotid IMT change did not differ between groups (biphasic -0.009 mm (95% CI -0.022 to 0.004), aspart+detemir 0.000 mm (95% CI -0.013 to 0.013), detemir -0.012 mm (95% CI -0.025 to 0.000)). HbA1c was more reduced with biphasic (-1.0% (95% CI -1.2 to -0.8)) compared with the aspart+detemir (-0.4% (95% CI -0.6 to -0.3)) and detemir (-0.3% (95% CI -0.4 to -0.1)) groups (p<0.001). Weight gain was higher in the biphasic (3.3 kg (95% CI 2.7 to 4.0) and aspart+detemir (3.2 kg (95% CI 2.6 to 3.9)) compared with the detemir group (1.9 kg (95% CI 1.3 to 2.6)). Insulin dose was higher with detemir (1.6 IU/kg/day (95% CI 1.4 to 1.8)) compared with biphasic (1.0 IU/kg/day (95% CI 0.9 to 1.1)) and aspart+detemir (1.1 IU/kg/day (95% CI 1.0 to 1.3)) (p<0.001). Number of participants with severe hypoglycaemia and serious adverse events did not differ. CONCLUSIONS: Carotid IMT change did not differ between 3 insulin regimens despite differences in HbA1c, weight gain and insulin doses. The trial only reached 46% of planned sample size and lack of power may therefore have affected our results. TRIAL REGISTRATION NUMBER: NCT00657943.

IDegLira Improves Both Fasting and Postprandial Glucose Control as Demonstrated Using Continuous Glucose Monitoring and a Standardized Meal Test.

OBJECTIVE: IDegLira is a novel, fixed-ratio combination of the long-acting basal insulin, insulin degludec, and the long-acting glucagon-like peptide-1 analog liraglutide. We studied the effect of IDegLira versus its components on postprandial glucose (PPG) in type 2 diabetes. METHODS: In this substudy, 260 (15.6%) of the original 1663 patients with inadequate glycemic control participating in a 26-week, open-label trial (DUAL I) were randomized 2:1:1 to once-daily IDegLira, insulin degludec or liraglutide. Continuous glucose monitoring (CGM) for 72 hours and a meal test were performed. RESULTS: At week 26, IDegLira produced a significantly greater decrease from baseline in mean PPG increment (normalized iAUC0-4h) than insulin degludec (estimated treatment difference [ETD] -12.79 mg/dl [95% CI: -21.08; -4.68], P = .0023) and a similar magnitude of decrease as liraglutide (ETD -1.62 mg/dl [95% CI: -10.09; 6.67], P = .70). CGM indicated a greater reduction in change from baseline in PPG increment (iAUC0-4h) for IDegLira versus insulin degludec over all 3 main meals (ETD -6.13 mg/dl [95% CI: -10.27, -1.98], P = .0047) and similar reductions versus liraglutide (ETD -1.80 mg/dl [95% CI: -2.52, 5.95], P = .4122). Insulin secretion ratio and static index were greater for IDegLira versus insulin degludec (P = .048 and P = .006, respectively) and similar to liraglutide (P = .45 and P = .895, respectively). CONCLUSIONS: Once-daily IDegLira provides significantly better PPG control following a mixed meal test than insulin degludec. The improvement is at least partially explained by higher endogenous insulin secretion and improved beta cell function with IDegLira. The benefits of liraglutide on PPG control are maintained across all main meals in the combination.

Vitamin D, carotid intima-media thickness and bone structure in patients with type 2 diabetes.

Despite aggressive treatment of cardiovascular disease (CVD) risk factors individuals with type 2 diabetes (T2D) still have increased risk of cardiovascular morbidity and mortality. The primary aim of this study was to examine the cross-sectional association between total (25-hydroxy vitamin D (25(OH)D)) and risk of CVD in patients with T2D. Secondary objective was to examine the association between 25(OH)D and bone health. A Danish cohort of patients with T2D participating in a randomised clinical trial were analysed. In total 415 patients (68% men, age 60±9 years (mean±s.d.), duration of diabetes 12±6 years), including 294 patients (71%) treated with insulin. Carotid intima-media thickness (IMT) and arterial stiffness (carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM)) were measured by ultrasound scan as indicators of CVD. Bone health was assessed by bone mineral density and trabecular bone score measured by dual energy X-ray absorptiometry. In this cohort, 214 patients (52%) were vitamin D deficient (25(OH)D <50 nmol/l). Carotid IMT was 0.793±0.137 mm, DC was 0.0030±0.001 mmHg, YEM was 2354±1038 mmHg and 13 (3%) of the patients were diagnosed with osteoporosis. A 25(OH)D level was not associated with carotid IMT or arterial stiffness (P>0.3) or bone health (P>0.6) after adjustment for CVD risk factors. In conclusion, 25(OH)D status was not associated with carotid IMT, arterial stiffness or bone health in this cohort of patients with T2D. To explore these associations and the association with other biomarkers further, multicentre studies with large numbers of patients are required.

A protocol for a randomised, double-blind, placebo-controlled study of the effect of LIraglutide on left VEntricular function in chronic heart failure patients with and without type 2 diabetes (The LIVE Study).

INTRODUCTION: Heart failure is one of the most common cardiovascular complications of diabetes and the most disabling and deadly complication too. Many antidiabetic agents have been associated with increased morbidity and mortality in a subset of patients with chronic heart failure (CHF); thus, new treatment modalities are warranted. Interestingly, a beneficial effect of the incretin hormone, GLP-1, on cardiac function has been suggested in patients with diabetes and patients without diabetes. Liraglutide (Victoza) is a GLP-1 analogue developed for the treatment of type 2 diabetes (T2D); however, its impact on cardiac function has not previously been investigated in patients with CHF. This prompted us to investigate whether liraglutide treatment for 24 weeks improves left ventricular ejection fraction (LVEF) in patients with CHF with and without T2D compared with placebo treatment. METHODS AND ANALYSIS: An investigator-initiated, multicentre, randomised, double-blind, parallel, placebo-controlled intervention trial. In total, 240 patients with CHF (with and without T2D) with LVEF≤45% will be randomised to either subcutaneous injection of liraglutide 1.8 mg or matching placebo once daily for 24 weeks. The effect of liraglutide on left ventricular function will be evaluated by advanced echocardiography, including three-dimensional contrast echocardiography. ETHICS AND DISSEMINATION: The study will be performed and monitored according to the Good Clinical Practice-International Conference on Harmonisation (GCP-ICH) regulations and conducted according to the principles of the Helsinki Declaration. The Danish Medicines Agency, the local Research Ethics Committee and the Danish Data Protection Agency have approved the study. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT01472640.

Impact of type 2 diabetes susceptibility variants on quantitative glycemic traits reveals mechanistic heterogeneity.

Patients with established type 2 diabetes display both ß-cell dysfunction and insulin resistance. To define fundamental processes leading to the diabetic state, we examined the relationship between type 2 diabetes risk variants at 37 established susceptibility loci, and indices of proinsulin processing, insulin secretion, and insulin sensitivity. We included data from up to 58,614 nondiabetic subjects with basal measures and 17,327 with dynamic measures. We used additive genetic models with adjustment for sex, age, and BMI, followed by fixed-effects, inverse-variance meta-analyses. Cluster analyses grouped risk loci into five major categories based on their relationship to these continuous glycemic phenotypes. The first cluster (PPARG, KLF14, IRS1, GCKR) was characterized by primary effects on insulin sensitivity. The second cluster (MTNR1B, GCK) featured risk alleles associated with reduced insulin secretion and fasting hyperglycemia. ARAP1 constituted a third cluster characterized by defects in insulin processing. A fourth cluster (TCF7L2, SLC30A8, HHEX/IDE, CDKAL1, CDKN2A/2B) was defined by loci influencing insulin processing and secretion without a detectable change in fasting glucose levels. The final group contained 20 risk loci with no clear-cut associations to continuous glycemic traits. By assembling extensive data on continuous glycemic traits, we have exposed the diverse mechanisms whereby type 2 diabetes risk variants impact disease predisposition.

Does DNA methylation of PPARGC1A influence insulin action in first degree relatives of patients with type 2 diabetes?

Epigenetics may play a role in the pathophysiology of type 2 diabetes (T2D), and increased DNA methylation of the metabolic master regulator peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) has been reported in muscle and pancreatic islets from T2D patients and in muscle from individuals at risk of T2D. This study aimed to investigate DNA promoter methylation and gene expression of PPARGC1A in skeletal muscle from first degree relatives (FDR) of T2D patients, and to determine the association with insulin action as well as the influence of family relation. We included 124 Danish FDR of T2D patients from 46 different families. Skeletal muscle biopsies were excised from vastus lateralis and insulin action was assessed by oral glucose tolerance tests. DNA methylation and mRNA expression levels were measured using bisulfite sequencing and quantitative real-time PCR, respectively. The average PPARGC1A methylation at four CpG sites situated 867-624 bp from the transcription start was associated with whole-body insulin sensitivity in a paradoxical positive manner (ß = 0.12, P = 0.03), supported by a borderline significant inverse correlation with fasting insulin levels (ß = -0.88, P = 0.06). Excluding individuals with prediabetes and overt diabetes did not affect the overall result. DNA promoter methylation was not associated with PPARGC1A gene expression. The familiality estimate of PPARGC1A gene expression was high (h(2) = 79±27% (h(2)±SE), P = 0.002), suggesting genetic regulation to play a role. No significant effect of familiality on DNA methylation was found. Taken together, increased DNA methylation of the PPARGC1A promoter is unlikely to play a major causal role for the development of insulin resistance in FDR of patients with T2D.

Further evidence that mutations in INS can be a rare cause of Maturity-Onset Diabetes of the Young (MODY).

BACKGROUND: Insulin gene (INS) mutations have recently been described as a common cause of permanent neonatal diabetes (PNDM) and a rare cause of diabetes diagnosed in childhood or adulthood. METHODS: INS was sequenced in 116 maturity-onset diabetes of the young (MODYX) patients (n = 48 Danish and n = 68 Czech), 83 patients with gestational diabetes mellitus (GDM), 34 type 1 diabetic patients screened negative for glutamic acid decarboxylase (GAD), and 96 glucose tolerant individuals. The control group was randomly selected from the population-based sampled Inter99 study. RESULTS: One novel heterozygous mutation c.17G>A, R6H, was identified in the pre-proinsulin gene (INS) in a Danish MODYX family. The proband was diagnosed at 20 years of age with mild diabetes and treated with diet and oral hypoglycaemic agent. Two other family members who carried the INS R6H were diagnosed with diabetes when 51 years old and with GDM when 27 years old, respectively. A fourth mutation carrier had normal glucose tolerance when 20 years old. Two carriers of INS R6H were also examined twice with an oral glucose tolerance test (OGTT) with 5 years interval. They both had a approximately 30% reduction in beta-cell function measured as insulinogenic index. In a Czech MODYX family a previously described R46Q mutation was found. The proband was diagnosed at 13 years of age and had been treated with insulin since onset of diabetes. Her mother and grandmother were diagnosed at 14 and 35 years of age, respectively, and were treated with oral hypoglycaemic agents and/or insulin. CONCLUSION: Mutations in INS can be a rare cause of MODY and we conclude that screening for mutations in INS should be recommended in MODYX patients.

Genetic variation in GIPR influences the glucose and insulin responses to an oral glucose challenge.

Glucose levels 2 h after an oral glucose challenge are a clinical measure of glucose tolerance used in the diagnosis of type 2 diabetes. We report a meta-analysis of nine genome-wide association studies (n = 15,234 nondiabetic individuals) and a follow-up of 29 independent loci (n = 6,958-30,620). We identify variants at the GIPR locus associated with 2-h glucose level (rs10423928, beta (s.e.m.) = 0.09 (0.01) mmol/l per A allele, P = 2.0 x 10(-15)). The GIPR A-allele carriers also showed decreased insulin secretion (n = 22,492; insulinogenic index, P = 1.0 x 10(-17); ratio of insulin to glucose area under the curve, P = 1.3 x 10(-16)) and diminished incretin effect (n = 804; P = 4.3 x 10(-4)). We also identified variants at ADCY5 (rs2877716, P = 4.2 x 10(-16)), VPS13C (rs17271305, P = 4.1 x 10(-8)), GCKR (rs1260326, P = 7.1 x 10(-11)) and TCF7L2 (rs7903146, P = 4.2 x 10(-10)) associated with 2-h glucose. Of the three newly implicated loci (GIPR, ADCY5 and VPS13C), only ADCY5 was found to be associated with type 2 diabetes in collaborating studies (n = 35,869 cases, 89,798 controls, OR = 1.12, 95% CI 1.09-1.15, P = 4.8 x 10(-18)).

Insulin gene mutations resulting in early-onset diabetes: marked differences in clinical presentation, metabolic status, and pathogenic effect through endoplasmic reticulum retention.

OBJECTIVE: Heterozygous mutations in the human preproinsulin (INS) gene are a cause of nonsyndromic neonatal or early-infancy diabetes. Here, we sought to identify INS mutations associated with maturity-onset diabetes of the young (MODY) or nonautoimmune diabetes in mid-adult life, and to explore the molecular mechanisms involved. RESEARCH DESIGN AND METHODS: The INS gene was sequenced in 16 French probands with unexplained MODY, 95 patients with nonautoimmune early-onset diabetes (diagnosed at <35 years) and 292 normoglycemic control subjects of French origin. Three identified insulin mutants were generated by site-directed mutagenesis of cDNA encoding a preproinsulin-green fluorescent protein (GFP) (C-peptide) chimera. Intracellular targeting was assessed in clonal beta-cells by immunocytochemistry and proinsulin secretion, by radioimmunoassay. Spliced XBP1 and C/EBP homologous protein were quantitated by real-time PCR. RESULTS: A novel coding mutation, L30M, potentially affecting insulin multimerization, was identified in five diabetic individuals (diabetes onset 17-36 years) in a single family. L30M preproinsulin-GFP fluorescence largely associated with the endoplasmic reticulum (ER) in MIN6 beta-cells, and ER exit was inhibited by approximately 50%. Two additional mutants, R55C (at the B/C junction) and R6H (in the signal peptide), were normally targeted to secretory granules, but nonetheless caused substantial ER stress. CONCLUSIONS: We describe three INS mutations cosegregating with early-onset diabetes whose clinical presentation is compatible with MODY. These led to the production of (pre)proinsulin molecules with markedly different trafficking properties and effects on ER stress, demonstrating a range of molecular defects in the beta-cell.

Variant near ADAMTS9 known to associate with type 2 diabetes is related to insulin resistance in offspring of type 2 diabetes patients--EUGENE2 study.

BACKGROUND: A meta-analysis combining results from three genome-wide association studies and followed by large-scale replication identified six novel type 2 diabetes loci. Subsequent studies of the effect of these variants on estimates of the beta-cell function and insulin sensitivity have been inconclusive. We examined these variants located in or near the JAZF1 (rs864745), THADA (rs7578597), TSPAN8 (rs7961581), ADAMTS9 (rs4607103), NOTCH2 (rs10923931) and the CDC123/CAMK1D (rs12779790) genes for associations with measures of pancreatic beta-cell function and insulin sensitivity. METHODOLOGY/RESULTS: Oral and intravenous glucose stimulated insulin release (n = 849) and insulin sensitivity (n = 596) estimated from a hyperinsulinemic euglycemic clamp were measured in non-diabetic offspring of type 2 diabetic patients from five European populations. Assuming an additive genetic model the diabetes-associated major C-allele of rs4607103 near ADAMTS9 associated with reduced insulin-stimulated glucose uptake (p = 0.002) during a hyperinsulinemic euglycemic clamp. However, following intravenous and oral administration of glucose serum insulin release was increased in individuals with the C-allele (p = 0.003 and p = 0.01, respectively). A meta-analyse combining clamp and IVGTT data from a total of 905 non-diabetic individuals showed that the C-risk allele associated with decreased insulin sensitivity (p = 0.003) and increased insulin release (p = 0.002). The major T-allele of the intronic JAZF1 rs864745 conferring increased diabetes risk was associated with increased 2(nd) phase serum insulin release during an IVGTT (p = 0.03), and an increased fasting serum insulin level (p = 0.001). The remaining variants did not show any associations with insulin response, insulin sensitivity or any other measured quantitative traits. CONCLUSION: The present studies suggest that the diabetogenic impact of the C-allele of rs4607103 near ADAMTS9 may in part be mediated through decreased insulin sensitivity of peripheral tissues.

[Diabetes in infants may be treated with sulfonylurea as a replacement for insulin]. / Spaedbørnsdiabetes kan ofte behandles med sulfonylurinstof i stedet for insulin.

A two-month-old Danish girl was admitted to the hospital in diabetic ketoacidosis and diagnosed with permanent neonatal diabetes mellitus (PNDM). She received continuous insulin treatment until she was genetically tested at the Steno Diabetes Centre. She carried a KCNJ11 Arg201His mutation, an activating mutation in the KCNJ11-gene which encodes the ATP-sensitive potassium subunit Kir6.2 in the beta cell which is responsible for insulin secretion. As recommended in the literature, she was successfully shifted from insulin therapy to sulfonylurea tablets at the age of three years and nine months. PNDM-patients should be screened for gene mutations regardless of current age.

Single-nucleotide polymorphism rs7754840 of CDKAL1 is associated with impaired insulin secretion in nondiabetic offspring of type 2 diabetic subjects and in a large sample of men with normal glucose tolerance.

CONTEXT: CDKAL1 is a recently discovered susceptibility gene for type 2 diabetes. OBJECTIVE: Our objective was to investigate the impact of rs7754840 of CDKAL1 on insulin secretion, insulin sensitivity, and risk of type 2 diabetes. DESIGN AND SETTINGS: Study 1 (the EUGENE2 study) was a cross-sectional study including subjects from five white populations in Europe (Denmark, Finland, Germany, Italy, and Sweden). Study 2 is an ongoing prospective study of Finnish men. PARTICIPANTS: In study 1, 846 nondiabetic offspring of type 2 diabetic patients (age 40 +/- 10 yr; body mass index 26.7 +/- 5.0 kg/m(2)) participated. In study 2, subjects included 3900 middle-aged men (533 type 2 diabetic and 3367 nondiabetic subjects). INTERVENTIONS: INTERVENTIONS included iv glucose-tolerance test (IVGTT), oral glucose-tolerance test (OGTT), and euglycemic-hyperinsulinemic clamp in study 1 and OGTT in study 2. MAIN OUTCOME MEASURES: Parameters of insulin secretion, insulin resistance, and glucose tolerance status were assessed. RESULTS: In study 1, carriers of the GC and CC genotypes of rs7754840 had 11 and 24% lower first-phase insulin release in an IVGTT compared with that in carriers of the GG genotype (P = 0.002). The C allele was also associated with higher glucose area under the curve in an OGTT (P = 0.016). In study 2, rs7754840 was significantly associated with type 2 diabetes (P = 0.022) and markers of impaired insulin release [insulinogenic index (IGI), P = 0.012] in 2405 men with normal glucose tolerance. CONCLUSIONS: rs7754840 of CDKAL1 was associated with markers of impaired insulin secretion in two independent studies. Furthermore, rs7754840 was associated with type 2 diabetes in Finnish men (study 2). Therefore, CDKAL1 is likely to increase the risk of type 2 diabetes by impairing insulin secretion.

A novel -192c/g mutation in the proximal P2 promoter of the hepatocyte nuclear factor-4 alpha gene (HNF4A) associates with late-onset diabetes.

Recently, it has been shown that mutations in the P2 promoter of the hepatocyte nuclear factor (HNF)-4 alpha gene (HNF4A) cause maturity-onset diabetes of the young (MODY), while single nucleotide polymorphisms in this locus are associated with type 2 diabetes. In this study, we examined 1,189 bp of the P2 promoter and the associated exon 1D of HNF4A for variations associated with diabetes in 114 patients with type 2 diabetes, 72 MODYX probands, and 85 women with previous gestational diabetes mellitus. A -192c/g mutation was found in five patients. We screened 1,587 diabetic subjects and 4,812 glucose-tolerant subjects for the -192c/g mutation and identified 5 diabetic and 1 glucose-tolerant mutation carriers (P=0.004). Examination of the families showed that carriers of the -192c/g mutation had a significantly impaired glucose-stimulated insulin release and lower levels of serum total cholesterol compared with matched control subjects. Furthermore, the mutation disrupted the binding of an unidentified sequence-specific DNA binding complex present in human islet extracts. Also, two novel linked polymorphisms in the P2 promoter at positions -1107g/t and -858c/t were identified. These variants were not significantly associated with type 2 diabetes or any pre-diabetic traits. In conclusion, a rare, novel mutation that disrupts a protein binding site in the pancreatic HNF4A promoter associates with late-onset diabetes.