Comparison of fixed-dose rosiglitazone/metformin combination therapy with sulphonylurea plus metformin in overweight individuals with Type 2 diabetes inadequately controlled on metformin alone

AIM

This 52-week, randomized, double-blind, parallel-group study was designed to compare rosiglitazone/metformin fixed-dose combination therapy with combination sulphonylurea plus metformin therapy in overweight individuals with inadequately controlled type 2 diabetes mellitus.

METHOD

Individuals with inadequate glycaemic control (HbA (1c)> or =7%) while on metformin monotherapy (> or =0.85 g/day) entered a 4-week run-in period during which they received metformin 2 g/day. At the end of the run-in, individuals with fasting plasma glucose > or =7.0 mmol/l were randomized to treatment with metformin (2 g/day) and either rosiglitazone (4 mg/day; RSG+MET [N=294]) or a sulphonylurea (glibenclamide 5 mg/day or gliclazide 80 mg/day; SU+MET [N=302]). Medications were up-titrated to maximum tolerated doses (rosiglitazone 8 mg, glibenclamide 15 mg or gliclazide 320 mg plus metformin 2 g/day) during the first 12 weeks of double-blind treatment. The primary efficacy end point was the change in HbA (1c) from baseline after 52 weeks of treatment.

RESULTS

RSG+MET was non-inferior to SU+MET with respect to changes in HbA (1c) after one year of treatment (DeltaHbA (1c)= -0.78% and -0.86%, respectively; treatment difference =0.09%, 95% CI=-0.08, 0.25). The HbA (1c) reductions with RSG+MET, but not SU+MET, were accompanied by significant improvements in measures of beta-cell function including proinsulin:insulin ratio. The degree of beta-cell failure was significantly greater with SU+MET compared to RSG+MET as measured by the coefficient of failure (0.543 vs. 0.055 HbA (1c)%/year, respectively, p=0.0002). The proportion of individuals who experienced hypoglycaemic events was significantly (p<0.0001) lower with RSG+MET (6%) than with SU+MET (30%). Diastolic ambulatory blood pressure and cardiovascular biomarkers (high-sensitivity C-reactive protein and plasminogen activator inhibitor-1) were also reduced following one year of treatment with RSG+MET but not SU+MET. Both treatments were generally well tolerated.

CONCLUSION

Fixed-dose combination therapy with rosiglitazone/metformin is non-inferior to sulphonylurea plus metformin combination therapy in reducing HbA (1c) over one year of treatment. Improvements in measures of beta-cell function suggest that the improvements in glycaemic control may be better maintained in long-term therapy with the rosiglitazone/metformin combination.

A M55V polymorphism in the SUMO4 gene is associated with a reduced prevalence of diabetic retinopathy in patients with Type 1 diabetes

AIMS

We studied the association between a functionally relevant M55V polymorphism in the SUMO4 gene with microvascular diabetic complications in patients with type 1 diabetes.

METHODS

223 patients with type 1 diabetes were studied using polymerase chain reaction and subsequent cleavage by restriction endonucleases for the M55V SUMO4 gene variant.

RESULTS

No effect of the polymorphism on diabetic neuropathy or diabetic nephropathy was found, but heterozygous or homozygous patients for the M55V polymorphism in the SUMO4 gene had a markedly reduced prevalence of diabetic retinopathy (odds ratio 0.37, 95%-confidence interval (CI) [0.32;0.43]; p=0.004). Furthermore, a multiple logistic regression model showed an age and diabetes duration independent effect of the M55V polymorphisms on the prevalence of diabetic retinopathy (p=0.03), but not of diabetic neuropathy or nephropathy.

CONCLUSIONS

Our data indicate that the M55V polymorphism in the SUMO4 gene is associated with a reduced risk of diabetic retinopathy in type 1 diabetes. Thus, the results of our study suggest that posttranslational modification of proteins via SUMO4 could contribute to the development of certain diabetic complications.

Improved vascular function upon pioglitazone treatment in type 2 diabetes is not associated with changes in mononuclear NF-kappaB binding activity

Thiazolidinediones such as pioglitazone have been shown to exert anti-inflammatory effects independent of their insulin sensitizing effects by reducing activation of the proinflammatory transcription factor NF-kappaB in animal models of experimental diabetes. Furthermore, short-term pioglitazone treatment ameliorates endothelial dysfunction in conduit arteries of patients with type 2 diabetes. Since inflammation is supposed to impair flow-mediated vasodilatation, we studied the effects of an 8-week pioglitazone intervention on endothelial function and mononuclear NF-kappaB activation in patients with type 2 diabetes. Twenty patients were included in a randomized, double-blind, placebo-controlled study receiving 30 mg pioglitazone or placebo, respectively. Flow-mediated endothelium dependent vasodilatation (FMD) of the brachial artery, NF-kappaB binding activity in peripheral blood mononuclear cells [pBMC, determined by electrophoretic mobility shift assay (EMSA)] and interleukin-6 (IL-6)-transcription rates (determined by real-time PCR) were measured at study entry and after eight weeks of intervention. Pioglitazone treatment resulted in a significant improvement of FMD (4.3%+/-3.3; p=0.003), while no effect was seen under placebo medication (2.0%+/-2.7; p=0.71). The correction of FMD was neither paralleled by a pioglitazone-dependent reduction in mononuclear NF-kappaB binding activity (DeltaNF-kappaB activity: pioglitazone: 9.2%+/-6.7, p=0.24; placebo: 5.7%+/-19.6; p=0.82) nor in NF-kappaB dependent gene transcription as determined for IL-6 (DeltaIL-6 pioglitazone: +1.8%+/-12.0, p=0.93; placebo: -0.2%+/-9.7; p=0.92). These data demonstrate for the first time that pioglitazone treatment improves endothelial dysfunction in patients with type 2 diabetes without affecting NF-kappaB binding activity and NF-kappaB dependent proinflammatory gene expression in pBMC.

Superconductivity on the border of weak itinerant ferromagnetism in UCoGe

We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. Magnetization measurements show that UCoGe is a weak ferromagnet with a Curie temperature T(C)=3 K and a small ordered moment m(0)=0.03 micro(B). Superconductivity is observed with a resistive transition temperature T(s)=0.8 K for the best sample. Thermal-expansion and specific-heat measurements provide solid evidence for bulk magnetism and superconductivity. The proximity to a ferromagnetic instability, the defect sensitivity of T(s), and the absence of Pauli limiting, suggest triplet superconductivity mediated by critical ferromagnetic fluctuations.

Long-term treatment of central Cushing's syndrome with rosiglitazone

CONTEXT

Central Cushing's syndrome is not always curable by surgery or radiation of the pituitary. Medical treatment is often not possible or effective. Some studies revealed beneficial effects of the PPARgamma (Peroxisome-Proliferator-Activator- Receptor-gamma)-agonist rosiglitazone (RG) in in vitro studies, animal models and short term clinical studies.

OBJECTIVE

of this study was to observe the long-term effects of RG-treatment on cortisol- and ACTH -secretion, clinical outcomes and morphological changes of the pituitary in patients with persistent ACTH-overproduction despite previous operation and radiation.

DESIGN, SETTING AND PATIENTS

14 patients with persistent central ACTH -production were included and monitored over a period up to 12 months. RG was administered daily and increased to a maximum dosage of 24 mg daily, according to the response of ACTH and cortisol secretion. ACTH and cortisol were measured at least every 4 weeks during RG treatment.

RESULTS

Patients were treated between 4 and 12 months with RG (mean 6.8 months). Compared to baseline, ACTH- and cortisol levels dropped significantly (p<0.01) after 12, 16, 20, 24 and 28 weeks but thereafter rose again during the study period, despite continuous RG- treatment and dose increase up to the maximum dosage. This was paralleled by reocurrence of clinical symptoms. MRI-scans were performed in 6 patients because of persisting visible adenoma, but showed no morphological changes.

CONCLUSION

RG seems not to be a long-term treatment option for patients with persistent central ACTH-evcess. Though, in order to reduce perioperative complications, short term treatment of patients could be an alternative.

Levels of three distinct p75 neurotrophin receptor forms found in human plasma are altered in type 2 diabetic patients

AIMS/HYPOTHESIS

The p75 neurotrophin receptor (p75NTR) has been shown to appear in the plasma of diabetic rats, possibly indicating diabetic neuropathy. The aim of this study was to use a semi-quantitative assay for human plasma p75NTR to investigate whether this receptor is a marker of peripheral diabetic neuropathy (DPN) and autonomic cardiovascular neuropathy (CAN) in type 2 diabetic patients.

SUBJECTS AND METHODS

Eighty type 2 diabetic patients and 25 controls without diabetes were analysed for p75NTR immunoreactivity by western blot analysis. DPN was assessed using the Neuropathy Disability Score (NDS). Cardiovascular autonomic function was detected using a standardised analysis of heart rate variability.

RESULTS

Three distinct p75NTR signals were detectable in human plasma at approximately 75, approximately 51 and approximately 24 kDa, representing the full length receptor (FL) and its intracellular domain (ICD) and extracellular domain (ECD), respectively. Levels of total plasma p75NTR immunoreactivity in patients with type 2 diabetes were similar to those in controls. Type 2 diabetic patients had significantly higher plasma levels of ICD and lower levels of ECD. However, there were no correlations of total p75NTR immunoreactivity or ECD or ICD immunoreactivity with NDS or aspects of CAN.

CONCLUSIONS/INTERPRETATION

Levels of the ECD of p75NTR are reduced and levels of the ICD are increased in the plasma of type 2 diabetic patients. None of the p75NTR subunits identified in human plasma seem to be a marker of peripheral or autonomic neuronal function in patients with type 2 diabetes.

Reducing mitochondrial fission results in increased life span and fitness of two fungal ageing models

Ageing of biological systems is accompanied by alterations in mitochondrial morphology, including a transformation from networks and filaments to punctuate units. The significance of these alterations with regard to ageing is not known. Here, we demonstrate that the dynamin-related protein 1 (Dnm1p), a mitochondrial fission protein conserved from yeast to humans, affects ageing in the two model systems we studied, Podospora anserina and Saccharomyces cerevisiae. Deletion of the Dnm1 gene delays the transformation of filamentous to punctuate mitochondria and retards ageing without impairing fitness and fertility typically observed in long-lived mutants. Our data further suggest that reduced mitochondrial fission extends life span by increasing cellular resistance to the induction of apoptosis and links mitochondrial dynamics, apoptosis and life-span control.

[Development of body weight during antidiabetic treatment]

Antidiabetic treatment of persons with type I or 2 diabetes mellitus is usually accompanied by body-weight gain. This is because any improvement in metabolism is associated with a decrease in glycosuria: Long-persisting loss of calories via urine is decreased. Furthermore, insulin has an antilipolytic effect simulates lipogenesis and promotes fluid retention. Hypoglycemia always necessitates additional intake of carbohydrates and thus also favors weight gain. During antidiabetic treatment with metformin the increase in body weight is significantly less than during treatment with sulphonylurea compounds or insulin. For this reason metformin is the drug of choice in the antidiabetic treatment of overweight diabetics. It is also superior to all other drugs when given together with insulin. The best results of insulin treatment with regard to weight control are obtained with basal insulin combined with metformin rather than insulin alone, prandial insulin substitution or intensified insulin treatment. If the aim is weight reduction, the pharmacokinetics of short-acting insulin analogs makes adaptation of insulin dose to reduced food intake easier than normal insulin. More attention than has previously been the case should be paid from the start to measures that prevent weight gain when planning antidiabetic treatment: prevention of weight gain is easier to achieve than weight reduction.

Effect of metformin plus roziglitazone compared with metformin alone on glycaemic control in well-controlled Type 2 diabetes

AIMS

To investigate the effect of metformin plus roziglitazione (RSGMET) compared with metformin alone (MET) on glycaemic control in well-controlled Type 2 diabetes.

METHODS

Subjects (drug naïve or those on glucose-lowering monotherapy) were randomized (n = 526), following a 4-week placebo run-in period, to RSGMET [4 mg rosiglitazone (RSG)/500 mg MET] or MET 500 mg. From weeks 2-18, medication was escalated every 4 weeks (based on gastrointestinal tolerability), then remained at RSGMET 8 mg/2 g or MET 3 g for 14 weeks.

RESULTS

RSGMET reduced HbA(1c) from 7.2 +/- 0.6 to 6.7 +/- 0.8% at week 32, compared with a reduction from 7.2 +/- 0.6 to 6.8 +/- 0.9% with MET (treatment difference -0.13%; P = 0.0357). More subjects achieved an HbA(1c) value of </= 6.5% at week 32 with RSGMET (51.6 vs. 43.7%), but the treatment difference was not significant (odds ratio 1.37, P = 0.0949). RSGMET produced larger reductions from baseline in mean fasting plasma glucose (adjusted difference -0.62 mmol/l, P < 0.0001), with the odds ratio of achieving a target of < 7.0 mmol/l being 2.33 (P < 0.0001). Statistically significant differences in favour of RSGMET relative to MET were seen for homeostatic model assessment (HOMA)-derived estimates of insulin sensitivity and pancreatic B-cell function, C-reactive protein (CRP), and systolic blood pressure. Overall rates of gastrointestinal adverse events (relevant to the known profile of MET) were comparable, but with a lower incidence of diarrhoea (8 vs. 18%) with RSGMET. Hypoglycaemia was reported in </= 7% subjects per group.

CONCLUSIONS

RSGMET provided similar short-term glycaemic control to MET with greater improvements in estimates of insulin sensitivity, B-cell function and CRP, with less diarrhoea and low risk of biochemical hypoglycaemia, suggesting that early use of combination therapy may be appropriate.

Incidence of Radioiodine Induced Graves' Disease in Patients with Multinodular Toxic Goiter

In this study, we assessed the incidence of Graves' disease (GD) following radioiodine therapy (RIT) in a large cohort of well characterized patients with autonomy in comparison to the clinical course of control patients with thyroidal autonomy not definitively treated with (131)I or surgery. 622 consecutive patients were treated with (131)I for autonomy (unifocal: n = 321; multifocal: n = 199; disseminated: n = 102) and followed up for at least 6 months post RIT. 108 consecutive patients with autonomy not definitively treated (unifocal: n = 49; multifocal: n = 42; disseminated: n = 11) followed up for at least 6 months served as controls. Initial evaluation and follow-up included determination of FT3, FT4, TSH, autoantibodies against the thyroid peroxidase (anti-TPO) and TSH-receptor antibodies (TRAb) by highly sensitive radio receptor-assay, quantitative thyroid scintigraphy and sonography. After 6 months, GD was newly diagnosed in 1/321 patients with unifocal autonomy, in 1/199 patients with multifocal autonomy and in 0/108 control patients. In patients with disseminated autonomy (group C), GD was diagnosed significantly more often compared to the other groups (5/102 patients; 4,1 %; p < 0.05). In conclusion, RIT may induce Graves' disease in a few cases with toxic multinodular goiter. The incidence in this population is small. Compared with patients suffering from uni- or multifocal autonomy, subjects with disseminated autonomy have a more than tenfold higher risk for the development of GD.

Efficacy and safety of topiramate in combination with metformin in the treatment of obese subjects with type 2 diabetes: a randomized, double-blind, placebo-controlled study

OBJECTIVE

To investigate the efficacy and safety of topiramate in obese subjects with type 2 diabetes treated with metformin.

DESIGN

This was a multicenter, double-blind, placebo-controlled trial. All subjects received a non-pharmacological program of diet, exercise and behavioral modification throughout the study; the assigned diet was 600 kcal/day less than the subject's individually calculated energy expenditure. After a 6-week single-blind placebo run-in, subjects were randomized to placebo, topiramate 96 mg/day or topiramate 192 mg/day. Following an 8-week titration period, subjects remained on their assigned dose for 52 weeks. However, the sponsor ended the study early in order to develop a new controlled-release formulation with the potential to enhance tolerability and simplify dosing in this patient population. A total of 646 obese men and women (age: 18-75 years, body mass index: 27-50 kg/m(2)) with an established history of type 2 diabetes mellitus controlled by metformin monotherapy were randomized. Efficacy was assessed in a pre-determined modified intent-to-treat (MITT) population of 307 subjects whose randomization date would have allowed them to complete 24 weeks on study medication before the announcement of study termination.

MEASUREMENTS

Joint primary efficacy parameters were mean percent change in weight and change in glycosylated hemoglobin (HbA(1c)) from baseline to week 24.

RESULTS

Subjects in the placebo, topiramate 96 mg/day and topiramate 192 mg/day groups lost 1.7%, 4.5% (P<0.001) and 6.5% (P<0.001), respectively, of their baseline body weight and had absolute decreases in HbA(1c) of 0.1%, 0.4% (P<0.001) and 0.6% (P<0.001) (MITT, last observation carried forward). Topiramate-treated subjects also experienced statistically significant decreases in systolic blood pressure. Most common adverse events were paresthesia and events related to the central nervous system.

CONCLUSIONS

Topiramate was effective for weight reduction and improvement in glycemic control in obese subjects with type 2 diabetes treated with metformin monotherapy. Further study in obese diabetics is warranted.