Long-term effects of metformin on endothelial function in type 2 diabetes: a randomized controlled trial.

OBJECTIVES: We investigated whether metformin can improve endothelial function and decrease inflammatory activity, and thereby decrease the risk of atherothrombotic disease. SUBJECTS AND DESIGN: A randomized, placebo-controlled trial with a follow-up period of 4.3 years set in the outpatient clinics of three nonacademic hospitals (Hoogeveen, Meppel and Coevorden Hospitals, the Netherlands). A total of 390 patients with type 2 diabetes treated with insulin were included. Either metformin 850 mg or placebo (one to three times daily) was added to insulin therapy. Urinary albumin excretion and plasma levels of von Willebrand factor (vWf), soluble vascular adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), C-reactive protein (CRP) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured at baseline and after 4, 17, 30, 43 and 52 months. RESULTS: Metformin significantly reduced levels of vWF, sVCAM-1, t-PA, PAI-1, CRP and sICAM-1, which, except for CRP, remained significant after adjustment for baseline differences in age, sex, smoking and severity of previous cardiovascular (CV) disease. No effects on urinary albumin excretion or sE-selectin were observed. The improvements in vWf and sVCAM-1 statistically explained about 34% of the reduction in the risk of CV morbidity and mortality associated with metformin treatment in this study. CONCLUSIONS: Metformin is associated with improvement in some (vWF and sVCAM-1) but not all markers of endothelial function, which may explain why it is associated with a decreased risk of CV disease in type 2 diabetes.

Characterization of the interaction of doxorubicin with (poly)phosphoinositides in model systems. Evidence for specific interaction with phosphatidylinositol-monophosphate and -diphosphate.

The anticancer drug doxorubicin penetrates into Langmuir monolayers containing phosphoinositides. Upon binding of doxorubicin to phosphoinositide-containing SUV, its fluorescence is self-quenched due to self-association. As compared to other anionic phospholipids, as much as 2- to 3-fold larger effects were obtained with PIP and PIP2, in mixtures of these lipids with DOPC. Doxorubicin competes efficiently with the non-penetrating antibiotic neomycin for binding to PIP2. According to its penetration, specific binding of doxorubicin was half-maximal at 5-15 microM. It is likely that also in biological membranes doxorubicin binds specifically to PIP and PIP2.

Reactions of glutathione with the catechol, the ortho-quinone and the semi-quinone free radical of etoposide. Consequences for DNA inactivation.

Etoposide [4'-demethylepipodophyllotoxin-9-(4,6-O-ethylidene-beta- D-glucopyranoside)] can be metabolized to DNA-inactivating catechol, ortho-quinone and semi-quinone free radical derivatives which may contribute to its cytotoxicity. In this paper, we examined in vitro whether glutathione (GSH), which is known to react easily with quinoid compounds, could interact with the active etoposide intermediates and in this way influence the cytotoxicity of the parent compound. To this end, reactions of GSH with the etoposide intermediates were studied, using HPLC and ESR measurements, together with the effects of GSH on the biological inactivation of single-stranded (ss) and double-stranded (RF) phi X174 DNA by these compounds. From the results it could be determined that: (a) GSH does not react with the catechol and, as a consequence, has no effect on the reaction of this intermediate of etoposide with ss and RF phi X174 DNA; (b) GSH reacts with the ortho-quinone most likely by formation of a conjugate and by two-electron reduction to the catechol, resulting in a partial protection of ss and RF phi X174 DNA against inactivation by this species; and (c) GSH protects ss phi X174 DNA against inactivation by the semi-quinone free radical of etoposide probably by conjugation with this species.

Combined metformin and insulin therapy for patients with type 2 diabetes mellitus.

OBJECTIVE: This study was undertaken to assess the effects of combined treatment with insulin and metformin in patients with type 2 diabetes mellitus in whom dietary measures, weight control, and oral antihyperglycemic therapy had failed. BACKGROUND: Insulin resistance in peripheral tissues, increased hepatic gluconeogenesis, and impaired insulin secretion are the underlying factors in the development of type 2 diabetes. Metformin is a biguanide antihyperglycemic agent that increases peripheral insulin sensitivity, reduces hepatic gluconeogenesis, and decreases intestinal glucose absorption. METHODS: Thirty-one patients (24 women, 7 men; mean age, 61.8 years; mean body mass index [BMI], 28.0 kg/m2) were enrolled in this randomized, double-blind, 2-way, crossover, placebo-controlled study. Patients with type 2 diabetes who were treated previously with insulin or oral hypoglycemic agents and who had a glycosylated hemoglobin (HbA1c) level >9% or a fasting blood glucose level >8 mmol/L were included. Patients who were being treated with oral agents were switched to insulin therapy and required to maintain stable blood glucose control for 2 months prior to randomization. Patients received insulin plus either metformin 1,700 mg/d or placebo for 5 months, followed by a 2-month washout period, and were then crossed over to the other treatment arm for 5 months of additional treatment (total treatment period: 12 months). RESULTS: Thirty patients completed the study; 1 patient withdrew early because of hypoglycemia. Compared with placebo, metformin produced significant reductions from overall baseline in mean daily insulin dose requirement (-8.69 units (17.2%], P < 0.001), HbA1c level (-0.74 [9.9%], P = 0.005), serum fructosamine level (-44.40 micromol/L, P = 0.026), 24-hour blood glucose profile (P = 0.008), and total cholesterol level (-0.42 mmol/L, P = 0.005). No treatment effects were observed on body weight, blood pressure, serum high-density lipoprotein cholesterol levels, or serum triglyceride levels. There was no correlation between BMI and reduction in HbA1C. No major side effects were reported. CONCLUSIONS: Combination therapy with metformin and insulin improves glycemic control and reduces insulin requirements. with no major side effects, in patients with type 2 diabetes and may improve the risk profile in this patient population.

Discontinuation of metformin in type 2 diabetes patients treated with insulin.

BACKGROUND: Metformin added to insulin therapy in type 2 diabetic patients improves glycaemic control and decreases the required daily dose of insulin (DDI). Metformin should be discontinued if cardiac, hepatic or renal failure develops. We examined whether glycaemic control can be maintained after metformin cessation. METHODS: We included 45 type 2 diabetic patients treated with insulin plus metformin, and 45 matched controls treated with insulin only. After discontinuation of metformin in the first group, we aimed for tight fasting and postprandial blood glucose levels, 4-7 and 4-10 mmol/l, respectively, in both groups. During 12 weeks we assessed glycaemic control every two weeks and, if necessary, adjusted the insulin dosage. RESULTS: In the group in which metformin was discontinued, DDI increased from 67.9 +/- 22.9 to 92.2 +/- 29.4 IU (p < 0.001) leaving glycaemic control unchanged. In the controls, glycated haemoglobin (GHb) decreased by 0.93% (p < 0.001), while DDI increased slightly from 62.4 +/- 22.9 to 72.3 +/- 27.3 IU (p < 0.001). The increase in DDI was larger in patients in whom metformin was discontinued than in the controls (p < 0.001). CONCLUSIONS: In type 2 diabetic patients treated with insulin plus metformin, glycaemic control can be maintained after discontinuation of metformin by increasing the DDI substantially (20 to 36%) during application of an intensified treatment protocol.

Does metformin decrease blood pressure in patients with Type 2 diabetes intensively treated with insulin?

AIMS: We investigated in a double-blind study whether metformin reduces blood pressure (BP) in patients with Type 2 diabetes intensively treated with insulin. METHODS: A total of 220 patients with Type 2 diabetes were asked to undergo 24-h ambulatory BP monitoring (24-h ABPM). One hundred and eighty-two gave informed consent. Eighty-nine were randomized to metformin and 93 to placebo. Thirty-five subjects dropped out (13 placebo, 22 metformin users); 147 patients underwent a second 24-h ABPM, 16 weeks after randomization. RESULTS: Systolic BP (SBP), diastolic BP (DBP), pulse BP (PP), mean BP (MP) and heart rate (HR) were measured as office BP measurements and as 24-h ABPM for 24-h, day and night. Office BP measurements did not differ significantly between the placebo- and metformin-treated groups for any BP measure, but showed a non-significant trend for SBP reduction with metformin use (mean baseline-adjusted difference, metformin minus placebo: -4.2 mmHg, 95% CI, -9.9 to +1.5; P = 0.15). The baseline-adjusted differences of the ambulatory measurements were -0.2 mmHg (95% CI, -2.9 to +2.6) for the 24-h SBP, and +1.1 mmHg (95% CI, -0.7 to +2.8) for the 24-h DBP. On the whole, BP differences between metformin- and placebo-treated groups were not statistically significant. The only significant difference was for night-time PP (baseline-adjusted difference: -2.2 mmHg; 95% CI, -4.2 to -0.2). These results were not different after adjustment for age and diabetes duration, or for (changes in) body mass index, glycated haemoglobin, insulin dose or plasma homocysteine. CONCLUSION: Metformin does not significantly affect BP in patients with Type 2 diabetes intensively treated with insulin.

Effects of short-term treatment with metformin on markers of endothelial function and inflammatory activity in type 2 diabetes mellitus: a randomized, placebo-controlled trial.

OBJECTIVES: The UK Prospective Diabetes Study (UKPDS) showed that treatment with metformin decreases macrovascular morbidity and mortality independent of glycaemic control. We hypothesized that metformin may achieve this by improving endothelial function and chronic, low-grade inflammation. Data on this issue are scarce and we therefore tested, in the setting of a randomized, placebo-controlled trial, whether metformin can affect endothelial function and low-grade inflammation. DESIGN: The Hyperinsulinaemia the Outcome of its Metabolic Effects (HOME) trial is a double-blind trial, in which all patients were randomized to receive either metformin or placebo in addition to insulin therapy. At the beginning and the end of a 16-week treatment period fasting blood samples were drawn and a physical examination was carried out. SETTING: The trial was conducted in the outpatient clinics of three nonacademic hospitals (Hoogeveen, Meppel and Coevorden; the Netherlands). SUBJECTS: Patients were included if they were between 30 and 80 years of age; had received a diagnosis of diabetes after the age of 25; had never had an episode of ketoacidosis; and their blood glucose-lowering treatment previously consisted of oral agents but now only consisted of either insulin (n = 345) or insulin and metformin (n = 45). We excluded pregnant women and women trying to become pregnant, patients with a Cockroft-Gault-estimated creatinine clearance <50 mL min(-1), or low plasma cholinesterase (reference value <3.5 units L(-1)), patients with congestive heart failure (New York Heart Association class III/IV), or patients with other serious medical or psychiatric disease. A total of 745 eligible patients were approached; 390 gave informed consent and were randomized (196 metformin, 194 placebo). About 353 patients completed 16 weeks of treatment (171 metformin, 182 placebo). MAIN OUTCOME MEASURES: The HOME trial was designed to study the metabolic and cardiovascular effects of metformin during a follow-up of 4 years. Presented here are the results of an interim analysis after 16 weeks of treatment. RESULTS: When compared with placebo, metformin treatment was associated with an increase in urinary albumin excretion of 21% (-1 to +48; P = 0.06); a decrease in plasma von Willebrand factor of 6% (-10 to -2; P = 0.0007); a decrease in soluble vascular cell adhesion molecule-1 of 4% (-7 to -2; P = 0.0002); a decrease in soluble E-selectin of 6% (-10 to -2; P = 0.008); a decrease in tissue-type plasminogen activator of 16% (-20 to -12; P < 0.0001); and a decrease in plasminogen activator inhibitor-1 of 20% (-27 to -10; P = 0.0001). These changes could not be explained by metformin-associated changes in glycaemic control, body weight or insulin dose. Markers of inflammation, i.e. C-reactive protein and soluble intercellular adhesion molecule-1, did not change with metformin treatment. CONCLUSIONS: In patients with type 2 diabetes treated with insulin, metformin treatment was associated with improvement of endothelial function, which was largely unrelated to changes in glycaemic control, but not with improvement of chronic, low-grade inflammation.

Effects of short-term treatment with metformin on serum concentrations of homocysteine, folate and vitamin B12 in type 2 diabetes mellitus: a randomized, placebo-controlled trial.

OBJECTIVE: Metformin is a key treatment option in type 2 diabetes. However, metformin may decrease vitamin B12 levels and increase levels of homocysteine, a cardiovascular risk factor. We investigated whether 16 weeks of treatment with metformin affects serum concentrations of homocysteine, folate and vitamin B12 in subjects with type 2 diabetes treated with insulin. DESIGN: Placebo-controlled, randomized trial. MEASUREMENTS: at baseline and 16 weeks later. SETTING: This trial was conducted in the outpatient clinics of three general hospitals in The Netherlands. SUBJECTS: A total of 745 patients with type 2 diabetes, treated with insulin and not known with a contraindication for the use of metformin, were approached; 390 gave informed consent and entered the study. Thirty-seven subjects dropped out (12 placebo and 25 metformin users). INTERVENTION: Addition of metformin or placebo to insulin therapy. PRIMARY OUTCOME PARAMETERS: Serum homocysteine, folate, vitamin B12, indices of glycaemic control and body weight. RESULTS: Amongst those who completed 16 weeks of treatment, metformin use, as compared with placebo, was associated with an increase in homocysteine of 4% (0.2 to 8; P=0.039) and with decreases in folate [-7% (-1.4 to -13); P=0.024] and vitamin B12 [-14% (-4.2 to -24); P<0.0001]. In addition, the increase in homocysteine could be explained by the decreases in folate and vitamin B12. CONCLUSION: In patients with type 2 diabetes, 16 weeks of treatment with metformin reduces levels of folate and vitamin B12, which results in a modest increase in homocysteine. The clinical significance of these findings remains to be investigated.

Does psychosocial treatment enhance the efficacy of acamprosate in patients with alcohol problems?

AIMS: Acamprosate in combination with psychosocial treatment has been shown to be effective for the treatment of alcohol dependence. The goal of the present study was to determine whether the addition of psychosocial intervention to the medical prescription of acamprosate contributes to treatment outcome. METHODS: Patients (n = 248) meeting DSM-IV criteria for alcohol dependence or abuse were recruited in 14 outpatient treatment centres and randomized into one of three treatment conditions: acamprosate; acamprosate plus minimal intervention aimed at motivational enhancement (3-weekly sessions of 20 min); and acamprosate plus brief cognitive behavioural therapy (7-weekly sessions of 60 min). Acamprosate was prescribed for 28 weeks, medically monitored by a physician on six occasions lasting 10 min. Drinking behaviour, medication compliance and psychological distress were assessed throughout the treatment period. Follow-up assessment was undertaken 6 months after termination of pharmacological treatment. RESULTS: Of 241 patients with intention to treat (ITT), 114 (47.3%) remained in treatment for the full 28 weeks; 169 of the ITT population (70.1%) were seen for follow-up. No statistically significant differences were found between treatment groups for any of the drinking outcomes either at the end of the 28 weeks of treatment or at 6-month follow-up. There were no statistically significant differences in medication compliance, drop-out rates, or psychological distress. However, a significant interaction effect was observed between treatment centre and treatment group, indicating that brief interventions were differentially effective in different treatment centres. CONCLUSIONS: A clear supplemental value of minimal and brief psychosocial interventions to the prescription of acamprosate was not demonstrated. The widely held belief that pharmacotherapy for alcohol dependence should always be combined with psychosocial intervention is debatable and merits further research.