Meta-analysis: metformin treatment in persons at risk for diabetes mellitus

CoMET: a protocol for a randomised controlled trial of co-commencement of METformin as an adjunctive treatment to attenuate weight gain and metabolic syndrome in patients with schizophrenia newly commenced on clozapine

INTRODUCTION

Clozapine, while effective in treatment refractory schizophrenia, is associated with significant weight gain, heart disease and increased risk of type 2 diabetes mellitus (T2DM). Although there is evidence for weight loss with metformin for people with obesity who are already taking clozapine, there have been no published trials that have investigated the effect of metformin in attenuating weight gain at the time of clozapine initiation.

METHODS AND ANALYSIS

A 24-week double-blind placebo-controlled trial of concomitant prescription of metformin at clozapine commencement. Eighty-six people being commenced on clozapine will be randomised to placebo or metformin (variable dose, up to 2 g/day). The primary outcome is comparative end point body weight, between the placebo and metformin groups. Secondary outcomes are comparative rates of conversion to T2DM, alteration of metabolic syndrome parameters, proportion gaining >5% body weight and changes in diet and appetite. We will additionally examine biomarkers associated with change in weight among trial participants.

ETHICS AND DISSEMINATION

Ethics approval was granted by the Metro South Human Research Ethics Committee HREC/17/QPAH/538-SSA/17/QPAH/565. We plan to submit a manuscript of the results to a peer-reviewed journal, and present results at conferences, consumer forums and hospital grand rounds.

TRIAL REGISTRATION NUMBER

ACTRN12617001547336; Pre-results.

Unique pharmacology of a novel allosteric agonist/sensitizer insulin receptor monoclonal antibody

Objective

Insulin resistance is a key feature of Type 2 Diabetes (T2D), and improving insulin sensitivity is important for disease management. Allosteric modulation of the insulin receptor (IR) with monoclonal antibodies (mAbs) can enhance insulin sensitivity and restore glycemic control in animal models of T2D.

Methods

A novel human mAb, IRAB-A, was identified by phage screening using competition binding and surface plasmon resonance assays with the IR extracellular domain. Cell based assays demonstrated agonist and sensitizer effects of IRAB-A on IR and Akt phosphorylation, as well as glucose uptake. Lean and diet-induced obese mice were used to characterize single-dose in vivo pharmacological effects of IRAB-A; multiple-dose IRAB-A effects were tested in obese mice.

Results

In vitro studies indicate that IRAB-A exhibits sensitizer and agonist properties distinct from insulin on the IR and is translated to downstream signaling and function; IRAB-A bound specifically and allosterically to the IR and stabilized insulin binding. A single dose of IRAB-A given to lean mice rapidly reduced fed blood glucose for approximately 2 weeks, with concomitant reduced insulin levels suggesting improved insulin sensitivity. Phosphorylated IR (pIR) from skeletal muscle and liver were increased by IRAB-A; however, phosphorylated Akt (pAkt) levels were only elevated in skeletal muscle and not liver vs. control; immunochemistry analysis (IHC) confirmed the long-lived persistence of IRAB-A in skeletal muscle and liver. Studies in diet-induced obese (DIO) mice with IRAB-A reduced fed blood glucose and insulinemia yet impaired glucose tolerance and led to protracted insulinemia during a meal challenge.

Conclusion

Collectively, the data suggest IRAB-A acts allosterically on the insulin receptor acting non-competitively with insulin to both activate the receptor and enhance insulin signaling. While IRAB-A produced a decrease in blood glucose in lean mice, the data in DIO mice indicated an exacerbation of insulin resistance; these data were unexpected and suggested the interplay of complex unknown pharmacology. Taken together, this work suggests that IRAB-A may be an important tool to explore insulin receptor signaling and pharmacology.

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A novel anti-insulin receptor monoclonal antibody (IRAB-A) was identified that has both agonist and sensitizing activities.

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IRAB-A increases the receptor's affinity for insulin by binding to an allosteric site and does not compete with insulin.

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Mice injected once with IRAB-A show improved glycemia and reduced insulinemia, indicative of enhanced insulin sensitivity.

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In diet induced obese mice, the insulin sensitizing effect of IRAB-A appears to depend on the degree of insulin resistance.

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Chronic treatment of obese mice showed mixed effects on glucose homeostasis under normal fed or meal challenged conditions.

Pharmaceutical Interventions for Diabetes Prevention in Patients at Risk

With the rising incidence and prevalence rates of type 2 diabetes globally, it is imperative that diabetes prevention strategies are implemented to stem the flow of new cases. Successful interventions include both lifestyle modification and pharmaceutical agents, and large, multicentre, randomised, controlled studies in different populations have identified the benefits of both. However, translating positive trial outcomes to the real world is particularly challenging, as lifestyle interventions require regular reinforcement from healthcare professionals to be maintained. Pharmaceutical therapies may therefore play an adjunctive role in combination with lifestyle to prevent diabetes. Population-based strategies are also necessary to reduce sedentary behaviour and obesity. Well-established glucose-lowering therapies such as metformin, sulphonylureas, thiazolidinediones and insulin and newer agents such as incretin therapies and sodium glucose co-transporter 2 inhibitors have all been investigated in randomised controlled trials for diabetes prevention with varying success. Non-glucose-lowering therapies such as orlistat and renin angiotensin system blockers can prevent diabetes, whereas statins are associated with slightly increased risk. Diabetes prevention strategies should carefully consider the use of these agents according to individual patient circumstances and phenotypic profile.

Management Strategies for Posttransplant Diabetes Mellitus after Heart Transplantation: A Review

Posttransplant diabetes mellitus (PTDM) is a well-recognized complication of heart transplantation and is associated with increased morbidity and mortality. Previous studies have yielded wide ranging estimates in the incidence of PTDM due in part to variable definitions applied. In addition, there is a limited published data on the management of PTDM after heart transplantation and a paucity of studies examining the effects of newer classes of hypoglycaemic drug therapies. In this review, we discuss the role of established glucose-lowering therapies and the rationale and emerging clinical evidence that supports the role of incretin-based therapies (glucagon like peptide- (GLP-) 1 agonists and dipeptidyl peptidase- (DPP-) 4 inhibitors) and sodium-glucose cotransporter 2 (SGLT2) inhibitors in the management of PTDM after heart transplantation. Recently published Consensus Guidelines for the diagnosis of PTDM will hopefully lead to more consistent approaches to the diagnosis of PTDM and provide a platform for the larger-scale multicentre trials that will be needed to determine the role of these newer therapies in the management of PTDM.

The shifting paradigm in the treatment of type 2 diabetes mellitus-A cardiologist's perspective

In patients with diabetes mellitus, cardiovascular (CV) disease is the leading cause of morbidity and mortality. A multitude of contemporary antidiabetic agents presents different CV safety profiles. Metformin forms the cornerstone agent to reduce CV events. Newer agents, such as glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors, have appealing CV benefits. Insulin, dipeptidyl peptidase-4 inhibitors, and sulfonylureas have neutral CV effects. Cardiologists should familiarize themselves with these agents to promote comprehensive CV care in patients with diabetes mellitus.

Effects of metformin on blood pressure in nondiabetic patients: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effects of metformin on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in nondiabetic patients.

METHODS

In this meta-analysis, we systematically searched PubMed, Embase, and the Cochrane Library through March 2016, and randomized controlled trials assessing the effects of metformin treatment compared with placebo were included. Random-effects models were used to estimate pooled mean differences in SBP and DBP.

RESULTS

Twenty-eight studies from 26 articles consisting of 4113 participants were included. Pooled results showed that metformin had a significant effect on SBP (mean difference -1.98 mmHg; 95% confidence interval -3.61, -0.35; P = 0.02), but not on DBP (mean difference -0.67 mmHg; 95% confidence interval -1.74, 0.41; P = 0.22). In subgroup analysis, we found that the effect of metformin on SBP was significant in patients with impaired glucose tolerance or obesity (BMI ≥30 kg/m), with a mean reduction of 5.03 and 3.00 mmHg, respectively. Significant heterogeneity was found for both SBP (I = 60.0%) and DBP (I = 45.4%). A sensitivity analysis indicated that the pooled effects of metformin on SBP and DBP were robust to systematically dropping each trial. Furthermore, no evidence of significant publication bias from funnel plots or Egger's tests (P = 0.51 and 0.21 for SBP and DBP, respectively) was found.

CONCLUSION

This meta-analysis suggested that metformin could effectively lower SBP in nondiabetic patients, especially in those with impaired glucose tolerance or obesity.

Prediabetes: Beyond the Borderline

Prediabetes is a complex multifactorial metabolic disorder that extends beyond glucose control. Current studies have found that microvascular disease (neuropathy, nephropathy, and retinopathy), macrovascular disease (stroke, coronary artery disease, and peripheral vascular disease), periodontal disease, cognitive dysfunction, blood pressure changes, obstructive sleep apnea, low testosterone level, fatty liver disease, and cancer are some of conditions that are present with the onset of glycemic dysregulation. The presence of prediabetes increases the risk of developing type 2 diabetes 3-fold to 10-fold. The identification and treatment of prediabetes are imperative to prevent or delay the progression to type 2 diabetes.

Metformin-Associated Lactic Acidosis Undergoing Renal Replacement Therapy in Intensive Care Units: A Five-Million Population-Based Study in the North-West of Italy

BACKGROUND

Metformin-associated lactic acidosis (MALA) is a severe complication of drug administration with significant morbidity and mortality. So far no study in large population areas have examined the incidence, clinical profile and outcome of acute kidney injury (AKI)-MALA patients admitted in intensive care units (ICUs) and treated by renal replacement therapy (MALA-RRT).

METHODS

Retrospective analysis over a 6-year period (2010-2015) in Piedmont and Aosta Valley regions (5,305,940 inhabitants, 141,174 diabetics treated with metformin) of all MALA-RRT cases.

RESULTS

One hundred and seventeen cases of AKI-MALA-RRT were observed (12.04/100,000 metformin treated diabetics, 1.45% of all RRT-ICU patients). Survival rate was 78.3%. The average duration of RRT was 4.0 days at mean dialysis effluent of 977 mL/kg/day. At admission most patients were dehydrated, and experienced shock and oliguria.

CONCLUSION

Our data showed that MALA-RRT is a common complication, needing more prevention. Adopted policy of early, extended, continuous and high efficiency dialysis could contribute to an observed high survival rate. Video Journal Club "Cappuccino with Claudio Ronco" at http://www.karger.com/?doi=471917.

Metformin is associated with fewer major adverse cardiac events among patients with a new diagnosis of type 2 diabetes mellitus: A propensity score-matched nationwide study

Early type 2 diabetes mellitus (DM) may only require lifestyle modifications for glycemic control without the need for oral hypoglycemic agents (OHAs). Metformin is believed to improve cardiovascular outcomes in patients with DM, and it is considered to be a first-line therapy. However, it is unclear whether metformin is beneficial for patients with a new diagnosis of DM compared to those who do not need OHAs for glycemic control.Data were obtained from a population-based health care database in Taiwan. Patients with a new diagnosis of DM were enrolled if they received metformin monotherapy only between 1999 and 2010. A 4:1 propensity score-matched cohort of patients with a new diagnosis of DM who did not take OHAs or insulin during follow-up was also enrolled. The primary study endpoint was the occurrence of major adverse cardiovascular events (MACEs). The time to the endpoints was compared between groups using Cox proportional hazards models.A total of 474,410 patients with DM were enrolled. During a mean 5.8 years of follow-up, the incidence of MACEs was 1.072% (1072 per 100,000 person-years) in the metformin monotherapy group versus 1.165% in the lifestyle modification group (those who did not take OHAs) (P < .001). After adjusting for confounders, metformin independently protected the DM patients from MACEs (hazard ratio: 0.83, P < .001). The metformin group also had an improved MACE-free survival profile from year 1 to year 12 (P < .001).In addition to lifestyle modifications, the patients with a new diagnosis of DM treated with metformin monotherapy had a lower MACE rate than those who did not take OHAs. Our findings suggest that metformin may be given early to patients with a new diagnosis of DM, even when they do not need OHAs for glycemic control.

PREVENT-DM Comparative Effectiveness Trial of Lifestyle Intervention and Metformin

INTRODUCTION

Although the Diabetes Prevention Program and other clinical trials demonstrated the efficacy of intensive lifestyle interventions (ILI) and metformin to prevent type 2 diabetes, no studies have tested their comparative effects in pragmatic settings. This study was designed to compare the real-world effectiveness of ILI, metformin, and standard care among Hispanic women (Latinas) with prediabetes.

STUDY DESIGN

RCT.

SETTING/PARTICIPANTS

Ninety-two Latinas, who had a mean hemoglobin A1c of 5.9%, BMI of 33.3 kg/m², and waist circumference of 97.4 cm (38.3 inches), were recruited from an urban community and randomly assigned to ILI, metformin, or standard care using 1:1:1 allocation. Data were collected from 2013-2015 and analyzed in 2016.

INTERVENTION

The 12-month ILI was adapted from the Diabetes Prevention Program's ILI and delivered by community health workers (promotoras) over 24 sessions. Metformin participants received 850 mg twice daily. Those randomized to standard care continued their regular medical care.

MAIN OUTCOME MEASURES

Weight and secondary outcomes (waist circumference, blood pressure, hemoglobin A1c, fasting plasma glucose, insulin, and lipids) were assessed at baseline and 12 months.

RESULTS

ILI participants demonstrated significantly greater mean weight loss (-4.0 kg, 5.0%) than metformin (-0.9 kg, 1.1%) and standard care participants (+0.8 kg, 0.9%) (p<0.001). The difference in weight loss between metformin and standard care was not significant. The ILI group experienced a greater reduction in waist circumference than standard care (p=0.001), and a marginal improvement in hemoglobin A1c compared with metformin and standard care (p=0.063).

CONCLUSIONS

In the first comparative effectiveness trial of diabetes prevention treatments, a 12-month ILI produced significantly greater weight loss than metformin and standard care among Latinas with prediabetes. These data suggest that ILI delivered by promotoras is an effective strategy for preventing diabetes in this high-risk group, which may be superior to metformin. Future pragmatic trials involving larger samples should examine differences in diabetes incidence associated with these treatments.

Treatment with high dose salicylates improves cardiometabolic parameters: Meta-analysis of randomized controlled trials

INTRODUCTION

There is conflicting evidence regarding the efficacy of high dose salicylates in improving cardiometabolic risk in healthy and type 2 diabetes patients. We aimed to determine whether treatment with salicylates at an anti-inflammatory dose (≥1g daily) would improve cardiometabolic risk in healthy individuals and type 2 diabetes patients, compared to placebo.

METHODS

Medline, Medline-in-process, Embase, and all EBM databases were searched for studies published up to December 2016. Twenty-eight articles from 24 studies comprising 1591 participants were included. Two reviewers independently assessed the risk of bias and extracted data from included studies. Meta-analyses using random-effects model were used to analyze the data.

RESULTS

High dose salicylates (≥3g/d) decreased fasting glucose (MD -0.4mmol/l, 95% CI -0.54, -0.27) and glucose area under the curve (MD -0.41mmol/l, 95% CI -0.81, -0.01). Salicylates (≥3g/d) also increased fasting insulin (MD 2.4 μU/ml, 95% CI 0.3, 4.4), 2-h insulin (MD 25.4 μU/ml, 95% CI 8.2, 42.6), insulin secretion (MD 79.2, 95% CI 35, 123) but decreased fasting C-peptide (MD -0.11nmol/l, 95% CI -0.2, -0.04), insulin clearance (MD -0.26l/min, 95% CI -0.36, -0.16) and triglycerides (MD -0.36mmol/l, 95% CI -0.51, -0.21) and increased total adiponectin (MD 1.97μg/ml, 95% CI 0.99, 2.95). A lower salicylate dose (1-2.9g) did not change any cardiometabolic parameters (p>0.1). No significant difference was observed between those receiving salicylates and placebo following withdrawal due to adverse events.

CONCLUSIONS

High dose salicylates appear to improve cardiometabolic risk factors in healthy individuals and type 2 diabetes patients.

PROSPERO REGISTRATION NUMBER

CRD42015029826.

Metformin causes a futile intestinal-hepatic cycle which increases energy expenditure and slows down development of a type 2 diabetes-like state

OBJECTIVE

Metformin, the first line drug for treatment of type 2 diabetes, suppresses hepatic gluconeogenesis and reduces body weight in patients, the latter by an unknown mechanism.

METHODS

Mice on a high fat diet were continuously fed metformin in a therapeutically relevant dose, mimicking a retarded formulation.

RESULTS

Feeding metformin in pharmacologically relevant doses to mice on a high fat diet normalized HbA1c levels and ameliorated glucose tolerance, as expected, but also considerably slowed down weight gain. This was due to increased energy expenditure, since food intake was unchanged and locomotor activity was even decreased. Metformin caused lactate accumulation in the intestinal wall and in portal venous blood but not in peripheral blood or the liver. Increased conversion of glucose-1-¹³C to glucose-1,6-¹³C under metformin strongly supports a futile cycle of lactic acid production in the intestinal wall, and usage of the produced lactate for gluconeogenesis in liver.

CONCLUSIONS

The reported glucose-lactate-glucose cycle is a highly energy consuming process, explaining the beneficial effects of metformin given continuously on the development of a type 2 diabetic-like state in our mice.

Dynamics of diabetes and obesity: Epidemiological perspective

The purpose of this review article is to understand the current literature on obesity, diabetes and therapeutic avenues across the world. Diabetes is a chronic lifestyle condition that affects millions of people worldwide and it is a major health concern in our society. Diabetes and obesity are associated with various conditions, including non-modifiable and modifiable risk factors. Early detectable markers are not well established to detect pre-diabetes and as a result, it becomes diabetes. Several published epidemiological studies were assessed and the findings were summarized. Resources from published studies were used to identify criteria used for pre-diabetes, the role of diet in pre-diabetics and potential risks and characteristics associated with pre-diabetes. Preventive strategies are needed to combat diabetes. Individuals diagnosed with pre-diabetes need detailed education, need to fully understand the risk factors and have the ability to manage diabetes. Interventions exist that include chronic disease self-management programs, lifestyle interventions and pharmacological strategies. Obesity plays a large role in causing pre-diabetes and diabetes. Critical analysis of existing epidemiological research data suggests that additional research is needed to determine the efficacy of interventions. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Different clinical prognostic factors are associated with improved glycaemic control: findings from MARCH randomized trial

AIMS

Metformin and acarbose have comparable efficacy as initial therapy for HbA_1c reduction in Chinese patients with newly diagnosed Type 2 diabetes. However, not all participants achieved glycaemic control. Our aim was to discover a monotherapy predictor for therapeutic response in Type 2 diabetes on the basis of baseline features.

METHODS

Data from the MARCH trial were collected, resulting in 698 individuals being available for longitudinal analyses. All participants were divided into subgroups based on successful and unsuccessful achievement of the glycaemic target according to primary endpoints at week 24 (HbA_1c < 53 mmol/mol; 7.0%). Logistic regression analysis with stepwise variable selection was performed to assess the independent risk factors for good glycaemic control of monotherapy with metformin or acarbose.

RESULTS

Median HbA_1c was 66 ± 1 mmol/mol (8.2 ± 0.07%) in the metformin group at baseline, and 66 ± 1 mmol/mol (8.2 ± 0.07%) in the acarbose group. After 24 weeks of monotherapy, 79.8% of participants in the metformin group achieved glycaemic targets compared with 78.7% of those in the acarbose group. Multivariate regression analysis showed that BMI and fasting blood glucose were significant independent predictors for the maintenance of good glycaemic control in the metformin group, whereas phase I insulin secretion (Insulin/Glucose at 30 min, I30/G30) and duration of diabetes were associated with good glycaemic control in the acarbose group.

CONCLUSIONS

For newly diagnosed Type 2 diabetes, some clinical features and laboratory parameters are important prognostic factors for predicting drug responsiveness. Participants with a higher BMI and lower fasting blood glucose achieved good glycaemic control when metformin was selected as the initial treatment. Acarbose was best for participants with higher phase I insulin secretion (I30/G30) and shorter duration of Type 2 diabetes.

Substituting poly- and mono-unsaturated fat for dietary carbohydrate reduces hyperinsulinemia in women with polycystic ovary syndrome

OBJECTIVE

Hyperinsulinemia is a prevalent feature of polycystic ovary syndrome (PCOS), contributing to metabolic and reproductive manifestations of the syndrome. Weight loss reduces hyperinsulinemia but weight regain is the norm, thus preventing long-term benefits. In the absence of weight loss, replacement of dietary carbohydrate (CHO) with mono/polyunsaturated fat reduces ambient insulin concentrations in non-PCOS subjects. The current study evaluated whether this dietary intervention could ameliorate hyperinsulinemia in women with PCOS.

DESIGN/SETTING/PATIENTS

Obese women with PCOS (BMI 39 ± 7 kg/m²) and insulin resistance completed a crossover study (Stanford University Clinical Research Center) comparing two isocaloric diets, prepared by research dietitians, containing 60% CHO/25% fat versus 40% CHO/45% fat (both 15% protein and ≤7% saturated fat). After 3 weeks on each diet, daylong glucose, insulin, and fasting lipid/lipoproteins were measured.

RESULTS

Daylong glucose did not differ according to diet. Daylong insulin concentrations were substantially (30%) and significantly lower on the low CHO/higher fat diet. Beneficial changes in lipid profile were also observed.

CONCLUSIONS

Replacement of dietary CHO with mono/polyunsaturated fat yields clinically important reductions in daylong insulin concentrations, without adversely affecting lipid profile in obese, insulin-resistant women with PCOS. This simple and safe dietary intervention may constitute an important treatment for PCOS. ClinicalTrials.gov Identifier: NCT00186459.

Exercise in a Pill: The Latest on Exercise-Mimetics

There is increasing evidence that an active lifestyle benefits both body and brain. However, not everyone may be able to exercise due to disease, injury or aging-related frailty. Identification of cellular targets activated by physical activity may lead to the development of new compounds that can, to some extent, mimic systemic and central effects of exercise. This review will focus on factors relevant to energy metabolism in muscle, such as the 5’ adenosine monophosphate-activated protein kinase (AMPK) - sirtuin (SIRT1) - Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) pathway, and the molecules affecting it. In particular, putative exercise-mimetics such as AICAR, metformin, and GW501516 will be discussed. Moreover, plant-derived polyphenols such as resveratrol and (-)epicatechin, with exercise-like effects on the body and brain will be evaluated.

The desert gerbil Psammomys obesus as a model for metformin-sensitive nutritional type 2 diabetes to protect hepatocellular metabolic damage: Impact of mitochondrial redox state

Introduction

While metformin (MET) is the most widely prescribed antidiabetic drug worldwide, its beneficial effects in Psammomys obesus (P. obesus), a rodent model that mimics most of the metabolic features of human diabetes, have not been explored thoroughly. Here, we sought to investigate whether MET might improve insulin sensitivity, glucose homeostasis, lipid profile as well as cellular redox and energy balance in P. obesus maintained on a high energy diet (HED).

Materials and methods

P. obesus gerbils were randomly assigned to receive either a natural diet (ND) consisting of halophytic plants (control group) or a HED (diabetic group) for a period of 24 weeks. MET (50 mg/kg per os) was administered in both animal groups after 12 weeks of feeding, i.e., the time required for the manifestation of insulin resistance in P. obesus fed a HED. Parallel in vitro experiments were conducted on isolated hepatocytes that were shortly incubated (30 min) with MET and energetic substrates (lactate + pyruvate or alanine, in the presence of octanoate).

Results

In vivo, MET lowered glycemia, glycosylated haemoglobin, circulating insulin and fatty acid levels in diabetic P. obesus. It also largely reversed HED-induced hepatic lipid alterations. In vitro, MET increased glycolysis but decreased both gluconeogenesis and ketogenesis in the presence of glucogenic precursors and medium-chain fatty acid. Importantly, these changes were associated with an increase in cytosolic and mitochondrial redox states along with a decline in respiration capacity.

Conclusions

MET prevents the progression of insulin resistance in diabetes-prone P. obesus, possibly through a tight control of gluconeogenesis and fatty acid β-oxidation depending upon mitochondrial function. While the latter is increasingly becoming a therapeutic issue in diabetes, the gut microbiota is another promising target that would need to be considered as well.

Prospective evaluation of abnormal glucose metabolism and insulin resistance in patients with atypical endometrial hyperplasia and endometrial cancer

PURPOSE

Obesity and diabetes (DM) are known to increase the risk of endometrial cancer (EC). However, little is known about the prevalence of abnormal glucose metabolism and insulin resistance (IR) in EC patients. We aimed to evaluate the prevalence of abnormal glucose metabolism and IR in EC patients.

METHODS

We prospectively enrolled atypical endometrial hyperplasia (AEH) and EC patients who had received planned treatment at Chiba University Hospital, Japan. All patients, except those with a confirmed diagnosis of DM, underwent the 75-g oral glucose tolerance test (OGTT) before treatment. We evaluated the prevalence of obesity, defined as body mass index (BMI) ≥25, IR, abnormal glucose metabolism, and the associations between these three factors and the clinical characteristics of AEH and EC patients.

RESULTS

We enrolled 279 patients from April 2009 to March 2015. Of these, 56 had a confirmed diagnosis of DM. Abnormal OGTT results, including impaired fasting glucose (n = 7), impaired glucose tolerance (n = 69), and newly identified DM (n = 33), were noted in 109 patients. Obesity, IR, and abnormal glucose metabolism were observed in 49.8, 51.6, and 59.1% of patients, respectively. Abnormal glucose metabolism was significantly associated with age (P < 0.001), body mass index (P = 0.004), and IR status (P < 0.001) in multivariate analysis.

CONCLUSION

Abnormal glucose metabolism, IR, and obesity were highly prevalent in patients with AEH and EC. These results indicate that physicians should consider a patient's metabolic status in the postoperative management of AEH and EC patients.

A story of metformin-butyrate synergism to control various pathological conditions as a consequence of gut microbiome modification: Genesis of a wonder drug?

The most widely prescribed oral anti-diabetic agent today in the world today is a member of the biguanide class of drugs called metformin. Apart from its use in diabetes, it is currently being investigated for its potential use in many diseases such as cancer, cardiovascular diseases, Alzheimer's disease, obesity, comorbidities of diabetes such as retinopathy, nephropathy to name a few. Numerous in-vitro and in-vivo studies as well as clinical trials have been and are being conducted with a vast amount of literature being published every day. Numerous mechanisms for this drug have been proposed, but they have been unable to explain all the actions observed clinically. It is of interest that insulin has a stimulatory effect on cellular growth. Metformin sensitizes the insulin action but believed to be beneficial in cancer. Like -wise metformin is shown to have beneficial effects in opposite sets of pathological scenario looking from insulin sensitization point of view. This requires a comprehensive review of the disease conditions which are claimed to be affected by metformin therapy. Such a comprehensive review is presently lacking. In this review, we begin by examining the history of metformin before it became the most popular anti-diabetic medication today followed by a review of its relevant molecular mechanisms and important clinical trials in all areas where metformin has been studied and investigated till today. We also review novel mechanistic insight in metformin action in relation to microbiome and elaborate implications of such aspect in various disease states. Finally, we highlight the quandaries and suggest potential solutions which will help the researchers and physicians to channel their research and put this drug to better use.

Metformin: From Research to Clinical Practice

Metformin is the recommended first-line oral glucose-lowering drug initiated to control hyperglycemia in type 2 diabetes mellitus. It acts in the liver, small intestines, and skeletal muscles with its major effect on decreasing hepatic gluconeogenesis. It is safe, inexpensive, and weight neutral and can be associated with weight loss. It can reduce microvascular complication risk and its use is associated with a lower cardiovascular mortality compared with sulfonylurea therapy. It is also used to delay the onset of type 2 diabetes mellitus, in treating gestational diabetes, and in women with polycystic ovary syndrome.

The antidepressant-like activity of AC-5216, a ligand for 18KDa translocator protein (TSPO), in an animal model of diabetes mellitus

Diabetes mellitus is a chronic disease that is associated with depression. Also, depression is common in adults with type 2 diabetes mellitus (T2DM). Translocator protein (18kDa) (TSPO) and allopregnanolone play an important role in the depression treatment. However, few studies have evaluated TSPO and allopregnanolone in the treatment of depression in T2DM. AC-5216, a ligand for TSPO, produces anxiolytic- and antidepressant-like effects in animal models. The present study aimed to explore antidepressant-like effects of AC-5216 on diabetic rats. Following the development of diabetic model induced by high fat diet (HFD) feeding and streptozotocin (STZ), AC-5216 (0.3 and 1 mg/kg, i.g.) elicited the antidepressant-like effects in behavioral tests while these activities were blocked by TSPO antagonist PK11195 (3 mg/kg, i.p.). The levels of allopregnanolone in the prefrontal cortex and hippocampus were increased by AC-5216 (0.3 and 1 mg/kg, i.g.), which was antagonized by PK11195 (3 mg/kg, i.p.). The increased plasma glucose (PG) and decreased insulin (INS) in HFD-STZ rats were reversed by AC-5216 (0.3 and 1 mg/kg, i.g.). This study indicates that the antidepressant-like effects of AC-5216 on HFD-STZ rats, suggesting that TSPO may represent a novel therapeutic target for depression in T2DM.

Impact of Current and Emerging Glucose-Lowering Drugs on Body Weight in Type 2 Diabetes

Type 2 diabetes is a progressive disease, and most people with diabetes will eventually require adjunctive pharmacotherapy to optimize their glycemic control. As the majority of people with type 2 diabetes are overweight or obese, weight management is an essential component of diabetes management to improve their overall health and quality of life. Many of the currently available glucose-lowering drugs are associated with weight gain, which makes it challenging for both prescribing clinicians and patients. The 2015 Canadian Diabetes Association Clinical Practice Guidelines interim update on the pharmacologic management of type 2 diabetes recommend individualization of therapy and glycemic targets. Clinicians should take into consideration not only the drug's efficacy and safety profiles but also its propensity for causing hypoglycemia and weight gain. Given that the number of glucose-lowering drugs is expanding rapidly, a better understanding of the impacts of current and emerging therapies on body weight will serve as a useful guide. Metformin remains the first-line drug after diet and exercise therapy. The next add-on agent could be selected from the incretin or sodium-glucose cotransporter-2 inhibitor class because these drugs rarely cause hypoglycemia and may lead to modest weight loss. When insulin therapy is considered, choosing a basal insulin that is associated with less nocturnal hypoglycemia and weight gain is recommended. Emerging therapies using combination therapy of an incretin-sodium-glucose cotransporter 2 inhibitor or glucagon-like peptide-1 agonist-basal insulin hold promise to achieve robust glycemic control with weight loss and low risk for hypoglycemia.

Patient Perceptions About Prediabetes and Preferences for Diabetes Prevention

PURPOSE

The purpose of this study was to explore how adults with prediabetes perceive their risk of developing diabetes and examine their preferences for evidence-based treatment options to prevent diabetes.

METHODS

A qualitative study was conducted in 2 large Midwest primary care practices, involving in-depth semistructured interviews with 35 adult patients with prediabetes.

RESULTS

This ethnically diverse (77% nonwhite) sample of middle-aged primary care patients exhibited multiple diabetes risk factors. Knowledge gaps about prediabetes and its medical management were pervasive. Most patients overestimated the risk of developing diabetes and were not familiar with evidence-based treatment options for prediabetes. They suggested that receiving brief, yet specific information about these topics during the study interview motivated them to act. The majority of participants considered both intensive lifestyle intervention and metformin acceptable treatment options. Many preferred initial treatment with intensive lifestyle intervention but would take metformin if their efforts at lifestyle change failed and their primary care physician recommended it. Some participants expressed wanting to combine both treatments.

CONCLUSIONS

This qualitative study highlights potential opportunities to promote patient-centered dialogue about prediabetes in primary care settings. Providing patients specific information about the risk of developing diabetes and evidence-based treatment options to prevent or delay its onset may encourage action. Physicians' prediabetes counseling efforts should be informed by the finding that most patients consider both intensive lifestyle intervention and metformin acceptable treatment options.

Weight loss among women and men in the ASPIRE-VA behavioral weight loss intervention trial

OBJECTIVE

Weight loss was examined among women and men veterans in a clinical trial comparing Aspiring for Lifelong Health (ASPIRE), a "small changes" weight loss program using either mixed-sex group-visit or telephone-based coaching, to MOVE!(®) , the usual mixed-sex group-based program.

METHODS

Linear mixed-effects models were used to calculate adjusted percent weight change at 12 months by sex and compare outcomes across arms within sex.

RESULTS

Analyses included 72 women (ASPIRE-Phone = 26; ASPIRE-Group = 26; MOVE! = 20) and 409 men (ASPIRE-Phone = 136; ASPIRE-Group = 134; MOVE! = 139). At 12 months, women displayed significant weight loss from baseline in ASPIRE-Group (-2.6%) and MOVE! (-2.7%), but not ASPIRE-Phone (+0.2%). Between-arm differences in weight change among women were: ASPIRE-Group versus ASPIRE-Phone, -2.8% (P = 0.15); MOVE! versus ASPIRE-Phone, -2.8% (P = 0.20); and ASPIRE-Group versus MOVE!, 0.0% (P = 1.0). At 12 months, men lost significant weight from baseline across arms (ASPIRE-Phone, -1.5%; ASPIRE-Group, -2.5%; MOVE!, -1.0%). Between-arm differences in weight change among men were: ASPIRE-Group versus ASPIRE-Phone, -0.9% (P = 0.23); MOVE! versus ASPIRE-Phone, +0.5% (P = 0.76); ASPIRE-Group versus MOVE!, -1.5% (P = 0.03).

CONCLUSIONS

Mixed-sex, group-based programs can result in weight loss for both women and men veterans.

Effect of Sitagliptin and Metformin on Prediabetes Progression to Type 2 Diabetes - A Randomized, Double-Blind, Double-Arm, Multicenter Clinical Trial: Protocol for the Sitagliptin and Metformin in PreDiabetes (SiMePreD) Study

Background

The high prevalence and incidence of type 2 diabetes mellitus (DM), and its associated morbidity and mortality, has prompted growing international interest and effort in the primary prevention of this disease. Primary prevention is possible since type 2 DM is preceded by prediabetes, offering a window opportunity to treat patients, and prevent the emergence of advanced disease. Sitagliptin is an oral dipeptidyl peptidase-IV inhibitor that preserves existing beta cell function and increases beta cell mass. These two effects have been demonstrated both in vitro and in animal studies, and current clinical data show that sitagliptin is safe. Metformin, a biguanide, reduces insulin resistance and inhibits hepatic gluconeogenesis, and has an excellent safety profile. The combination of metformin and sitagliptin, targeting both characteristics of prediabetes (insulin resistance and progressive beta cell degeneration), may potentially slow or halt the progression from prediabetes to type 2 DM. This paper describes the rationale and design of the Sitagliptin and Metformin in PreDiabetes (SiMePreD) study.

Objective

The aim of this study is to determine the effect of sitagliptin and metformin on progression from prediabetes to type 2 DM. The objectives of the study are to determine the effects of metformin and placebo on glycemic endpoints, the effects of sitagliptin and metformin on glycemic endpoints, the effects of metformin and placebo on incidence of cardiovascular disease and death, and the effects of sitagliptin and metformin on incidence of cardiovascular disease and death.

Methods

This is a randomized, double-blind, multicenter clinical study that will determine if the combination of metformin and sitagliptin is effective in preventing the progression from prediabetes to type 2 DM. The study will contain two arms (metformin/sitagliptin and metformin/placebo). Primary endpoints include the number of subjects progressing from prediabetes to type 2 DM, the number of cardiovascular events, and the number of deaths. The planned duration of the study is five years, and 410 subjects will be included in each group. Data analyses will include clinically relevant measures (eg, numbers needed to treat and numbers needed to harm) and will be performed according to the intention-to-treat principle.

Results

This study is currently in the process of acquiring research funding.

Conclusions

The SiMePreD study is the first study to investigate the utility of sitagliptin in combination with metformin for the primary prevention of type 2 DM. 

Detecting Dysglycemia Using the 2015 United States Preventive Services Task Force Screening Criteria: A Cohort Analysis of Community Health Center Patients

BACKGROUND

In 2015, the United States Preventive Services Task Force (USPSTF) recommended targeted screening for prediabetes and diabetes (dysglycemia) in adults who are aged 40 to 70 y old and overweight or obese. Given increasing prevalence of dysglycemia at younger ages and lower body weight, particularly among racial/ethnic minorities, we sought to determine whether the current screening criteria may fail to identify some high-risk population subgroups.

METHODS AND FINDINGS

We investigated the performance of the 2015 USPSTF screening recommendation in detecting dysglycemia among US community health center patients. A retrospective analysis of electronic health record (EHR) data from 50,515 adult primary care patients was conducted. Longitudinal EHR data were collected in six health centers in the Midwest and Southwest. Patients with a first office visit between 2008 and 2010 were identified and followed for up to 3 y through 2013. We excluded patients who had dysglycemia at baseline and those with fewer than two office visits during the follow-up period. The exposure of interest was eligibility for screening according to the 2015 USPSTF criteria. The primary outcome was development of dysglycemia during follow-up, determined by: (1) laboratory results (fasting/2-h postload/random glucose ≥ 100/140/200 mg/dL [5.55/7.77/11.10 mmol/L] or hemoglobin A1C ≥ 5.7% [39 mmol/mol]); (2) diagnosis codes for prediabetes or type 2 diabetes; or (3) antidiabetic medication order. At baseline, 18,846 (37.3%) participants were aged ≥40 y, 33,537 (66.4%) were overweight or obese, and 39,061 (77.3%) were racial/ethnic minorities (34.6% Black, 33.9% Hispanic/Latino, and 8.7% Other). Overall, 29,946 (59.3%) patients had a glycemic test within 3 y of follow-up, and 8,478 of them developed dysglycemia. Only 12,679 (25.1%) patients were eligible for screening according to the 2015 USPSTF criteria, which demonstrated the following sensitivity and specificity (95% CI): 45.0% (43.9%-46.1%) and 71.9% (71.3%-72.5%), respectively. Racial/ethnic minorities were significantly less likely to be eligible for screening yet had higher odds of developing dysglycemia than whites (odds ratio [95% CI]: Blacks 1.24 [1.09-1.40]; Hispanics 1.46 [1.30-1.64]; and Other 1.33 [1.16-1.54]). In addition, the screening criteria had lower sensitivity in all racial/ethnic minority groups compared to whites. Limitations of this study include the ascertainment of dysglycemia only among patients with available test results and findings that may not be generalizable at the population level.

CONCLUSIONS

Targeted diabetes screening based on new USPSTF criteria may detect approximately half of adult community health center patients with undiagnosed dysglycemia and proportionately fewer racial/ethnic minorities than whites. Future research is needed to estimate the performance of these screening criteria in population-based samples.

Role of Brown Fat in Lipoprotein Metabolism and Atherosclerosis

Atherosclerosis, for which hyperlipidemia is a major risk factor, is the leading cause of morbidity and mortality in Western society, and new therapeutic strategies are highly warranted. Brown adipose tissue (BAT) is metabolically active in human adults. Although positron emission tomography-computed tomography using a glucose tracer is the golden standard to visualize and quantify the volume and activity of BAT, it has become clear that activated BAT combusts fatty acids rather than glucose. Here, we review the role of brown and beige adipocytes in lipoprotein metabolism and atherosclerosis, with evidence derived from both animal and human studies. On the basis of mainly data from animal models, we propose a model in which activated brown adipocytes use their intracellular triglyceride stores to generate fatty acids for combustion. BAT rapidly replenishes these stores by internalizing primarily lipoprotein triglyceride-derived fatty acids, generated by lipoprotein lipase-mediated hydrolysis of triglycerides, rather than by holoparticle uptake. As a consequence, BAT activation leads to the generation of lipoprotein remnants that are subsequently cleared via the liver provided that an intact apoE-low-density lipoprotein receptor pathway is present. Through these mechanisms, BAT activation reduces plasma triglyceride and cholesterol levels and attenuates diet-induced atherosclerosis development. Initial studies suggest that BAT activation in humans may also reduce triglyceride and cholesterol levels, but potential antiatherogenic effects should be assessed in future studies.

Metformin for Clozapine Associated Obesity: A Systematic Review and Meta-Analysis

BACKGROUND

Although clozapine is the gold-standard for treatment refractory schizophrenia, it has the worst metabolic profile of all antipsychotics. This is partly mediated by clozapine's impact on glucagon-like peptide (GLP-1). There is an absence of robust evidence for effective treatments for clozapine associated weight gain and metabolic syndrome. Metformin, with its role in increasing GLP-1 may aid weight loss among people on clozapine.

METHODS

We conducted a systematic-review and meta-analysis of metformin versus placebo for change in weight and metabolic syndrome for people on clozapine without diabetes mellitus. We searched the Cochrane Schizophrenia Group's trial register, Pubmed and Embase, as well as the following Chinese databases: the Chinese Biomedical Literature Service System and China Knowledge Resource Integrated Database. This was supplemented by hand searches of key papers.

RESULTS

Eight studies, of which three were from Chinese databases, with 478 participants were included. We found that metformin was superior to placebo in terms of weight loss (-3.12kg, 95%CI -4.88kg to -1.37kg) and BMI (-1.18kg/m2, 95%CI -1.76kg/m2 to -0.61kg/m2). Metformin significantly improved three of the five components of metabolic syndrome; waist circumference, fasting glucose and triglycerides. Sensitivity analysis on study quality and duration did not greatly impact results.

CONCLUSIONS

Metformin led to clinically meaningful weight loss among people on clozapine, and may reduce the rates of metabolic syndrome. Inclusion of metformin into the treatment protocols of people on clozapine, as tolerated, should be considered.

TRIAL REGISTRATION

PROSPERO registration number: CRD42015029723.

Developing criteria for evaluation of geroprotectors as a key stage toward translation to the clinic

In the coming decades, a massive shift in the aging segment of the population will have major social and economic consequences around the world. One way to offset this increase is to expedite the development of geroprotectors, substances that slow aging, repair age‐associated damage and extend healthy lifespan, or healthspan. While over 200 geroprotectors are now reported in model organisms and some are in human use for specific disease indications, the path toward determining whether they affect aging in humans remains obscure. Translation to the clinic is hampered by multiple issues including absence of a common set of criteria to define, select, and classify these substances, given the complexity of the aging process and their enormous diversity in mechanism of action. Translational research efforts would benefit from the formation of a scientific consensus on the following: the definition of ‘geroprotector’, the selection criteria for geroprotectors, a comprehensive classification system, and an analytical model. Here, we review current approaches to selection and put forth our own suggested selection criteria. Standardizing selection of geroprotectors will streamline discovery and analysis of new candidates, saving time and cost involved in translation to clinic.

Harnessing publicly available genetic data to prioritize lipid modifying therapeutic targets for prevention of coronary heart disease based on dysglycemic risk

Therapeutic interventions that lower LDL-cholesterol effectively reduce the risk of coronary artery disease (CAD). However, statins, the most widely prescribed LDL-cholesterol lowering drugs, increase diabetes risk. We used genome-wide association study (GWAS) data in the public domain to investigate the relationship of LDL-C and diabetes and identify loci encoding potential drug targets for LDL-cholesterol modification without causing dysglycemia. We obtained summary-level GWAS data for LDL-C from GLGC, glycemic traits from MAGIC, diabetes from DIAGRAM and CAD from CARDIoGRAMplusC4D consortia. Mendelian randomization analyses identified a one standard deviation (SD) increase in LDL-C caused an increased risk of CAD (odds ratio [OR] 1.63 (95 % confidence interval [CI] 1.55, 1.71), which was not influenced by removing SNPs associated with diabetes. LDL-C/CAD-associated SNPs showed consistent effect directions (binomial P = 6.85 × 10⁻⁵). Conversely, a 1-SD increase in LDL-C was causally protective of diabetes (OR 0.86; 95 % CI 0.81, 0.91), however LDL-cholesterol/diabetes-associated SNPs did not show consistent effect directions (binomial P = 0.15). HMGCR, our positive control, associated with LDL-C, CAD and a glycemic composite (derived from GWAS meta-analysis of four glycemic traits and diabetes). In contrast, PCSK9, APOB, LPA, CETP, PLG, NPC1L1 and ALDH2 were identified as “druggable” loci that alter LDL-C and risk of CAD without displaying associations with dysglycemia. In conclusion, LDL-C increases the risk of CAD and the relationship is independent of any association of LDL-C with diabetes. Loci that encode targets of emerging LDL-C lowering drugs do not associate with dysglycemia, and this provides provisional evidence that new LDL-C lowering drugs (such as PCSK9 inhibitors) may not influence risk of diabetes.

Effects of Metformin and Exercise Training, Alone or in Combination, on Cardiac Function in Individuals with Insulin Resistance

Introduction

In patients affected by insulin resistance (IR), metformin (MET) therapy has been shown to exert its positive effects by improving glucose tolerance and preventing the evolution to diabetes. Recently, it was shown that the addition of metformin to physical training did not improve sensitivity to insulin or peak oxygen consumption (peak VO2). The purpose of this study was to establish the effect of metformin and exercise, separately or in combination, on systolic left ventricular (LV) function in individuals with IR.

Methods

Seventy-five patients with IR were enrolled and subsequently assigned to MET, combination MET and exercise, or exercise alone. The LV systolic and diastolic functions were evaluated with standard echocardiography tissue Doppler imaging (TDI) and speckle tracking echocardiography at baseline and after 12 weeks of treatment.

Results

MET, administered alone or in association with exercise, improved longitudinal LV function, as evidenced by an increase in systolic (S) wave on TDI, alongside increases in longitudinal global strain and strain rate in comparison to the group undergoing physical training alone. The traditional echocardiographic parameters showed no statistically significant differences among the three groups before or after the different cycles of therapy.

Conclusions

Treatment with MET, either with or without exercise, but not exercise alone, produced a significant increase in global longitudinal LV systolic function at rest. These findings validate the observation that the use of MET alone or in association with exercise has a crucial role to counteract the negative effects of IR on cardiovascular function.

Electronic supplementary material

The online version of this article (doi:10.1007/s40119-016-0057-3) contains supplementary material, which is available to authorized users.

Phase II study of medroxyprogesterone acetate plus metformin as a fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer

BACKGROUND

Metformin, widely used in the treatment of type 2 diabetes mellitus, reduces the risk of cancer and relapse after treatment. Fertility-sparing treatment for endometrial cancer (EC) with progestin is associated with a high chance of disease regression, and the high relapse rate continues to be a problem. We assessed the efficacy of metformin in preventing recurrence after medroxyprogesterone acetate (MPA) as fertility-sparing treatment for atypical endometrial hyperplasia (AEH) and EC.

PATIENTS AND METHODS

This phase II study enrolled 17 patients with AEH and 19 patients with EC limited to the endometrium (age, 20-40 years). MPA (400 mg/day) and metformin (750-2250 mg/day) were administered for 24-36 weeks to achieve a complete response (CR). Metformin was administered until conception, even after MPA discontinuation. The primary end point was relapse-free survival (RFS) after remission. We analyzed all efficacy end points in the full analysis set.

RESULTS

The body mass index was ≥25 kg/m(2) in 27 patients (mean, 31 kg/m(2); range, 19-51 kg/m(2)), and the homeostasis model assessment for insulin resistance index was ≥2.5 in 24 patients (mean, 4.7; range, 0.7-21). Two patients showed progression at 12 weeks [6%; 95% confidence interval (CI) 2-18]. At 36 weeks, 29 (81%; 95% CI 65-90) patients achieved CR, and 5 (14%; 95% CI 6-29) patients achieved partial response. During a median follow-up of 38 months (range, 9-66 months) after remission, relapse was confirmed in three of the patients who had achieved CR (relapse rate, 10%). The 3-year estimated RFS rate was 89%. No patients experienced severe toxicity.

CONCLUSIONS

Metformin inhibited disease relapse after MPA therapy. The combination of metformin and MPA in EC treatment should be studied further.

TRIAL REGISTRATION NUMBER

UMIN 000002210.

The rationale, design, and baseline characteristics of PREVENT-DM: A community-based comparative effectiveness trial of lifestyle intervention and metformin among Latinas with prediabetes

Promotora Effectiveness Versus Metformin Trial (PREVENT-DM) is a randomized comparative effectiveness trial of a lifestyle intervention based on the Diabetes Prevention Program delivered by community health workers (or promotoras), metformin, and standard care. Eligibility criteria are Hispanic ethnicity, female sex, age ≥ 20 years, fluent Spanish-speaking status, BMI ≥ 23 kg/m(2), and prediabetes. We enrolled 92 participants and randomized them to one of the following three groups: standard care, DPP-based lifestyle intervention, or metformin. The primary outcome of the trial is the 12-month difference in weight between groups. Secondary outcomes include the following cardiometabolic markers: BMI, waist circumference, blood pressure, and fasting plasma glucose, hemoglobin A1C (HbA1c), total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and insulin. PREVENT-DM participants are socioeconomically disadvantaged Latinas with a mean annual household income of $15,527 ± 9922 and educational attainment of 9.7 ± 3.6 years. Eighty-six percent of participants are foreign born, 20% have a prior history of gestational diabetes, and 71% have a first-degree relative with diagnosed diabetes. At baseline, PREVENT-DM participants had a mean age of 45.1 ± 12.5 years, weight of 178.8 ± 39.3 lbs, BMI of 33.3 ± 6.5 kg/m(2), HbA1c of 5.9 ± 0.2%, and waist circumference of 97.4 ± 11.1cm. Mean baseline levels of other cardiometabolic markers were normal. The PREVENT-DM study successfully recruited and randomized an understudied population of Latinas with prediabetes. This trial will be the first U.S. study to test the comparative effectiveness of metformin and lifestyle intervention versus standard care among prediabetic adults in a "real-world" setting.

Metformin: risk-benefit profile with a focus on cancer

INTRODUCTION

Epidemiological evidence suggests an increased incidence of cancer in obese, prediabetic, and diabetic patients and a reduced risk of cancer incidence and mortality in diabetic patients on metformin compared with other antidiabetic drugs. In vitro studies support the efficacy of metformin in cancer therapy and prevention. Although metformin seems to be promising as a cancer chemopreventive or therapeutic drug, the principal consideration is whether metformin will be effective in cancer clinical trials for nondiabetic subjects or only in diabetics or subjects with insulin resistance. Safety of metformin is even more important in treating nondiabetic patients.

AREAS COVERED

The present review focuses on epidemiological data and clinical trials testing the efficacy of metformin on cancer, the safety in nondiabetic patients and the future development of this promising drug.

EXPERT OPINION

Meta-analyses of epidemiological in which metformin treatment has been used for diabetic patients show a positive trend for benefit; nevertheless, clinical data outcomes are preliminary and the results of ongoing trials are awaited. The different types of cancer, heterogeneity of populations and presence of comorbidity make it difficult to determine the benefits of metformin in cancer prevention and treatment.

Regulation of brown fat by AMP-activated protein kinase

Novel strategies are needed to reduce the obesity epidemic. One promising strategy is activation of brown adipose tissue (BAT), either via the brain or directly, which increases energy expenditure by combustion of fatty acids (FAs) into heat. The enzyme complex AMP-activated protein kinase (AMPK) is crucially involved in energy metabolism and is highly expressed in both brain and BAT, regulating thermogenesis. As a general rule, BAT activity and energy expenditure are increased either by suppression of AMPK activity in the brain, resulting in enhanced sympathetic outflow towards BAT, or by activation of AMPK in BAT. Targeting AMPK may thus hold therapeutic potential for the treatment of obesity and related disorders.

Deciphering Signaling Pathway Networks to Understand the Molecular Mechanisms of Metformin Action

A drug exerts its effects typically through a signal transduction cascade, which is non-linear and involves intertwined networks of multiple signaling pathways. Construction of such a signaling pathway network (SPNetwork) can enable identification of novel drug targets and deep understanding of drug action. However, it is challenging to synopsize critical components of these interwoven pathways into one network. To tackle this issue, we developed a novel computational framework, the Drug-specific Signaling Pathway Network (DSPathNet). The DSPathNet amalgamates the prior drug knowledge and drug-induced gene expression via random walk algorithms. Using the drug metformin, we illustrated this framework and obtained one metformin-specific SPNetwork containing 477 nodes and 1,366 edges. To evaluate this network, we performed the gene set enrichment analysis using the disease genes of type 2 diabetes (T2D) and cancer, one T2D genome-wide association study (GWAS) dataset, three cancer GWAS datasets, and one GWAS dataset of cancer patients with T2D on metformin. The results showed that the metformin network was significantly enriched with disease genes for both T2D and cancer, and that the network also included genes that may be associated with metformin-associated cancer survival. Furthermore, from the metformin SPNetwork and common genes to T2D and cancer, we generated a subnetwork to highlight the molecule crosstalk between T2D and cancer. The follow-up network analyses and literature mining revealed that seven genes (CDKN1A, ESR1, MAX, MYC, PPARGC1A, SP1, and STK11) and one novel MYC-centered pathway with CDKN1A, SP1, and STK11 might play important roles in metformin’s antidiabetic and anticancer effects. Some results are supported by previous studies. In summary, our study 1) develops a novel framework to construct drug-specific signal transduction networks; 2) provides insights into the molecular mode of metformin; 3) serves a model for exploring signaling pathways to facilitate understanding of drug action, disease pathogenesis, and identification of drug targets.

A deep understanding of a drug’s mechanisms of actions is essential not only in the discovery of new treatments but also in minimizing adverse effects. Here, we develop a computational framework, the Drug-specific Signaling Pathway Network (DSPathNet), to reconstruct a comprehensive signaling pathway network (SPNetwork) impacted by a particular drug. To illustrate this computational approach, we used metformin, an anti-diabetic drug, as an example. Starting from collecting the metformin-related upstream genes and inferring the metformin-related downstream genes, we built one metformin-specific SPNetwork via random walk based algorithms. Our evaluation of the metformin-specific SPNetwork by using disease genes and genotyping data from genome-wide association studies showed that our DSPathNet approach was efficient to synopsize drug’s key components and their relationship involved in the type 2 diabetes and cancer, even the metformin anticancer activity. This work presents a novel computational framework for constructing individual drug-specific signal transduction networks. Furthermore, its successful application to the drug metformin provides some valuable insights into the mode of metformin action, which will facilitate our understanding of the molecular mechanisms underlying drug treatments, disease pathogenesis, and identification of novel drug targets and repurposed drugs.

Prediabetes and lifestyle modification: time to prevent a preventable disease

More than 100 million Americans have prediabetes or diabetes. Prediabetes is a condition in which individuals have blood glucose levels higher than normal but not high enough to be classified as diabetes. People with prediabetes have an increased risk of Type 2 diabetes. An estimated 34% of adults have prediabetes. Prediabetes is now recognized as a reversible condition that increases an individual's risk for development of diabetes. Lifestyle risk factors for prediabetes include overweight and physical inactivity.Increasing awareness and risk stratification of individuals with prediabetes may help physicians understand potential interventions that may help decrease the percentage of patients in their panels in whom diabetes develops. If untreated, 37% of the individuals with prediabetes may have diabetes in 4 years. Lifestyle intervention may decrease the percentage of prediabetic patients in whom diabetes develops to 20%.Long-term data also suggest that lifestyle intervention may decrease the risk of prediabetes progressing to diabetes for as long as 10 years. To prevent 1 case of diabetes during a 3-year period, 6.9 persons would have to participate in the lifestyle intervention program. In addition, recent data suggest that the difference in direct and indirect costs to care for a patient with prediabetes vs a patient with diabetes may be as much as $7000 per year. Investment in a diabetes prevention program now may have a substantial return on investment in the future and help prevent a preventable disease.

Polycystic ovary syndrome: reviewing diagnosis and management of metabolic disturbances

Polycystic ovary syndrome (PCOS) is a common condition in women at reproductive age associated with reproductive and metabolic dysfunction. Proposed diagnosed criteria for PCOS include two out of three features: androgen excess, menstrual irregularity, and polycystic ovary appearance on ultrasound (PCO), after other causes of hyperandrogenism and dysovulation are excluded. Based on these diagnostic criteria, the most common phenotypes are the "classic PCOS"--hyperandrogenism and oligomenorrhea, with or without PCO; the "ovulatory phenotype"--hyperandrogenism and PCO in ovulatory women; and the "non-hyperandrogenic phenotype", in which there is oligomenorrhea and PCO, without overt hyperandrogenism. The presence of obesity may exacerbate the metabolic and reproductive disorders associated with the syndrome. In addition, PCOS women present higher risk for type 2 diabetes and higher prevalence of cardiovascular risk factors that seems to be associated with the classic phenotype. The main interventions to minimize cardiovascular and metabolic risks in PCOS are lifestyle changes, pharmacological therapy, and bariatric surgery. Treatment with metformin has been shown to improve insulin sensitivity, lowering blood glucose and androgen levels. These effects are more potent when combined with lifestyle interventions. In conclusion, besides reproductive abnormalities, PCOS has been associated to metabolic comorbidities, most of them linked to obesity. Confounders, such as the lack of standard diagnostic criteria, heterogeneity of the clinical presentation, and presence of obesity, make management of PCOS difficult. Therefore, the approach to metabolic abnormalities should be tailored to the risks and treatment goals of each individual woman.

Metformin activates a duodenal Ampk-dependent pathway to lower hepatic glucose production in rats

Metformin is a first-line therapeutic option for the treatment of type 2 diabetes, even though its underlying mechanisms of action are relatively unclear. Metformin lowers blood glucose levels by inhibiting hepatic glucose production (HGP), an effect originally postulated to be due to a hepatic AMP-activated protein kinase (AMPK)-dependent mechanism. However, studies have questioned the contribution of hepatic AMPK to the effects of metformin on lowering hyperglycemia, and a gut-brain-liver axis that mediates intestinal nutrient- and hormone-induced lowering of HGP has been identified. Thus, it is possible that metformin affects HGP through this inter-organ crosstalk. Here we show that intraduodenal infusion of metformin for 50 min activated duodenal mucosal Ampk and lowered HGP in a rat 3 d high fat diet (HFD)-induced model of insulin resistance. Inhibition of duodenal Ampk negated the HGP-lowering effect of intraduodenal metformin, and both duodenal glucagon-like peptide-1 receptor (Glp-1r)-protein kinase A (Pka) signaling and a neuronal-mediated gut-brain-liver pathway were required for metformin to lower HGP. Preabsorptive metformin also lowered HGP in rat models of 28 d HFD-induced obesity and insulin resistance and nicotinamide (NA)-streptozotocin (STZ)-HFD-induced type 2 diabetes. In an unclamped setting, inhibition of duodenal Ampk reduced the glucose-lowering effects of a bolus metformin treatment in rat models of diabetes. These findings show that, in rat models of both obesity and diabetes, metformin activates a previously unappreciated duodenal Ampk-dependent pathway to lower HGP and plasma glucose levels.

DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in human liver cancer cells

Metformin, one of the most commonly used drugs for patients with type 2 diabetes, recently has received much attention regarding its anti-cancer action. It is thought that the suppression of mTOR signaling is involved in metformin's anti-cancer action. Although liver cancer is one of the most responsive types of cancer for reduction of incidence by metformin, the molecular mechanism of the suppression of mTOR in liver remains unknown. In this study, we investigated the mechanism of the suppressing effect of metformin on mTOR signaling and cell proliferation using human liver cancer cells. Metformin suppressed phosphorylation of p70-S6 kinase, and ribosome protein S6, downstream targets of mTOR, and suppressed cell proliferation. We found that DEPTOR, an endogenous substrate of mTOR suppression, is involved in the suppressing effect of metformin on mTOR signaling and cell proliferation in human liver cancer cells. Metformin increases the protein levels of DEPTOR, intensifies binding to mTOR, and exerts a suppressing effect on mTOR signaling. This increasing effect of DEPTOR by metformin is regulated by the proteasome degradation system; the suppressing effect of metformin on mTOR signaling and cell proliferation is in a DEPTOR-dependent manner. Furthermore, metformin exerts a suppressing effect on proteasome activity, DEPTOR-related mTOR signaling, and cell proliferation in an AMPK-dependent manner. We conclude that DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in liver, and could be a novel target for anti-cancer therapy.

The effect of alcohol consumption on insulin sensitivity and glycemic status: a systematic review and meta-analysis of intervention studies

OBJECTIVE

Moderate alcohol consumption is associated with a reduced risk of type 2 diabetes. This reduced risk might be explained by improved insulin sensitivity or improved glycemic status, but results of intervention studies on this relation are inconsistent. The purpose of this study was to conduct a systematic review and meta-analysis of intervention studies investigating the effect of alcohol consumption on insulin sensitivity and glycemic status.

RESEARCH DESIGN AND METHODS

PubMed and Embase were searched up to August 2014. Intervention studies on the effect of alcohol consumption on biological markers of insulin sensitivity or glycemic status of at least 2 weeks' duration were included. Investigators extracted data on study characteristics, outcome measures, and methodological quality.

RESULTS

Fourteen intervention studies were included in a meta-analysis of six glycemic end points. Alcohol consumption did not influence estimated insulin sensitivity (standardized mean difference [SMD] 0.08 [-0.09 to 0.24]) or fasting glucose (SMD 0.07 [-0.11 to 0.24]) but reduced HbA1c (SMD -0.62 [-1.01 to -0.23]) and fasting insulin concentrations (SMD -0.19 [-0.35 to -0.02]) compared with the control condition. Alcohol consumption among women reduced fasting insulin (SMD -0.23 [-0.41 to -0.04]) and tended to improve insulin sensitivity (SMD 0.16 [-0.04 to 0.37]) but not among men. Results were similar after excluding studies with high alcohol dosages (>40 g/day) and were not influenced by dosage and duration of the intervention.

CONCLUSIONS

Although the studies had small sample sizes and were of short duration, the current evidence suggests that moderate alcohol consumption may decrease fasting insulin and HbA1c concentrations among nondiabetic subjects. Alcohol consumption might improve insulin sensitivity among women but did not do so overall.

Effect of metformin vs placebo on and metabolic factors in NCIC CTG MA.32

BACKGROUND

Metformin may improve metabolic factors (insulin, glucose, leptin, highly sensitive C-reactive protein [hs-CRP]) associated with poor breast cancer outcomes. The NCIC Clinical Trials Group (NCIC CTG) MA.32 investigates effects of metformin vs placebo on invasive disease-free survival and other outcomes in early breast cancer. Maintaining blinding of investigators to outcomes, we conducted a planned, Data Safety Monitoring Committee-approved, analysis of the effect of metformin vs placebo on weight and metabolic factors at six months, including examination of interactions with baseline body mass index (BMI) and insulin, in the first 492 patients with paired blood samples.

METHODS

Eligible nondiabetic subjects with T1-3, N0-3, M0 breast cancer who had completed surgery and (neo)adjuvant chemotherapy (if given) provided fasting plasma samples at random assignment and at six months. Glucose was measured locally; blood was aliquoted, frozen, and stored at -80°C. Paired plasma aliquots were analyzed for insulin, hs-CRP, and leptin. Spearman correlation coefficients were calculated and comparisons analyzed using Wilcoxon signed rank test. All statistical tests were two-sided.

RESULTS

Mean age was 52.1±9.5 years in the metformin group and 52.6 ± 9.8 years in the placebo group. Arms were balanced for estrogen/progesterone receptor, BMI, prior (neo)adjuvant chemotherapy, and stage. At six months, decreases in weight and blood variables were statistically significantly greater in the metformin arm (vs placebo) in univariate analyses: weight -3.0%, glucose -3.8%, insulin -11.1%, homeostasis model assessment -17.1%, leptin -20.2%, hs-CRP -6.7%; all P values were less than or equal to .03. There was no statistically significant interaction of change in these variables with baseline BMI or insulin.

CONCLUSIONS

Metformin statistically significantly improved weight, insulin, glucose, leptin, and CRP at six months. Effects did not vary by baseline BMI or fasting insulin.

The effects of metformin on weight loss in women with gestational diabetes: a pilot randomized, placebo-controlled trial

OBJECTIVE

We sought to compare weight loss in the first 6 weeks postpartum among women with gestational diabetes mellitus (GDM) treated with metformin or placebo, a promising therapy to reduce later risk of progression to diabetes mellitus.

STUDY DESIGN

We conducted a pilot, randomized trial of metformin vs placebo in postpartum women with GDM. Women with pre-GDM, unable to tolerate metformin, resumed on insulin or oral hypoglycemic agent, delivered <34 weeks' gestation, or with a body mass index <20 kg/m(2) were excluded. Women were randomized to either metformin 850 mg daily for 7 days, then metformin 850 mg twice a day for the next 5 weeks or placebo prescribed in a similar frequency. The subject, health care provider, and research staff were blinded to the treatment. The primary outcome was weight change from delivery to 6 weeks postpartum. Secondary outcomes included the percentage of women achieving their self-reported prepregnancy weight, reported medication adherence, adverse effects, and satisfaction. Differences in weight change between groups were determined by Wilcoxon rank sum test and in achieving prepregnancy weight by χ(2) test.

RESULTS

Of 114 women randomized, 79 (69.3%) completed the 6 weeks; 36 (45.6%) were randomized to metformin and 43 (54.4%) to placebo. Metformin and placebo groups were similar in median weight loss (6.3 kg [range, -0.3 to 19.8] vs 6.5 kg [range, -0.3 to 12.1], P = .988) and percentage of women achieving reported prepregnancy weight (41.7 vs 37.2%, P = .69). Self-reported adherence in taking >50% of medication was 75% at 3 weeks and 97% at 6 weeks. Nausea, diarrhea, and hypoglycemia were reported in approximately 11-17% of women and 56-63% reported dissatisfaction with the medication.

CONCLUSION

Women with GDM lost approximately 6 kg by 6 weeks' postpartum. This was similar in both groups and resulted in <50% of women achieving their prepregnancy weight. Although the reported adherence and satisfaction with the medication was high, adverse effects were reported with nearly 1 in 5 women including nausea, diarrhea, and hypoglycemia. Contrary to expectation, we found no evidence of benefit from metformin. However, longer treatment periods and larger studies with minimal attrition may be warranted.