Metformin and body weight

Effects of metformin on the glucose regulation, lipid levels and gut microbiota in high-fat diet with streptozotocin induced type 2 diabetes mellitus rats

OBJECTIVE

Metformin, an anti-diabetic drug, regulates blood glucose by affecting gut microbiotas. However, the potential mechanism underlying this effect remains unclear. This study aimed to evaluate the effect of metformin on glucose regulation, lipid levels, and the gut microbiota in rats with type 2 diabetes mellitus induced by a high-fat diet with streptozotocin.

RESEARCH DESIGN METHODS

Thirty Wistar rats was using in this experiment. T2DM rats were administered 300 mg/kg metformin for 8 weeks. The glucose regulation, lipid levels, organ coefficients, and gut microbiotawere measured by 16S rDNA.

RESULT

The metformin-gavaged rats exhibited significant improvements in blood glucose and serum lipid levels, accompanied by alterations in short-chain fatty acid levels and the intestinal microbiota (p < 0.05). In the diabetic rats, metformin potentially increased specific probiotics, thus improving the hypoglycaemic effects of the oral anti-diabetic drug. Further, damage to the liver and kidney was effectively alleviated in the metformin-gavaged rats.

CONCLUSION

This study's findings demonstrate that metformin exerts a positive anti-diabetic effect in HFD- and STZ-induced T2DM rats. These findings potentially provide a basis for the recommended use of metformin as a reliable oral drug for T2DM owing to its positive effect on the intestinal microbiota.

METFORMIN: FROM DIABETES TO CANCER TO PROLONGATION OF LIFE

The metformin molecule dates back to over a century, but its clinical use started in the '50s. Since then, its use in diabetics has grown constantly, with over 150 million users today. The therapeutic profile also expanded, with improved understanding of novel mechanisms. Metformin has a major activity on insulin resistance, by acting on the insulin receptors and mitochondria, most likely by activation of the adenosine monophosphate-activated kinase. These and associated mechanisms lead to significant lipid lowering and body weight loss. An anti-cancer action has come up in recent years, with mechanisms partly dependent on the mitochondrial activity and also on phosphatidylinositol 3-kinase resistance occurring in some malignant tumors. The potential of metformin to raise life-length is the object of large ongoing studies and of several basic and clinical investigations. The present review article will attempt to investigate the basic mechanisms behind these diverse activities and the potential clinical benefits. Metformin may act on transcriptional activity by histone modification, DNA methylation and miRNAs. An activity on age-associated inflammation (inflammaging) may occur via activation of the nuclear factor erythroid 2 related factor and changes in gut microbiota. A senolytic activity, leading to reduction of cells with the senescent associated secretory phenotype, may be crucial in lifespan prolongation as well as in ancillary properties in age-associated diseases, such as Parkinson's disease. Telomere prolongation may be related to the activity on mitochondrial respiratory factor 1 and on peroxisome gamma proliferator coactivator 1-alpha. Very recent observations on the potential to act on the most severe neurological disorders, such as amyotrophic lateral sclerosis and frontotemporal dementia, have raised considerable hope.

Optimizing metformin therapy in practice: Tailoring therapy in specific patient groups to improve tolerability, efficacy and outcomes

Metformin is the first-line medication for type 2 diabetes. It is effective and safe, provided some caution is taken in specific populations. In patients with chronic kidney disease, metformin may provide long-term benefits, and it is a first-line therapy for diabetes, but the estimated glomerular filtration rate (eGFR) must be assessed regularly, to minimize the risk for metformin accumulation. When eGFR is 30-60 mL/min/1.73m2, the dose should be reconsidered, and sick-days education provided. Metformin should be discontinued when eGFR falls below 30 mL/min/1.73m2. Metformin accumulation may increase the risk for lactic acidosis if concomitant risk factors for hyperlactataemia (liver or respiratory insufficiency, sepsis, acute heart failure) are present; in these conditions, metformin is contraindicated, even although the available evidence is reassuring. Patients on metformin often complain of gastrointestinal side effects (mainly diarrhoea and nausea) during therapy initiation, but they may sometimes occur after years of stable therapy. These usually resolve if the dose is carefully titrated, or by switching to the extended-release formulation. Patients with obesity may benefit from the significant, although modest, metformin-associated weight loss and appetite reduction. During pregnancy, metformin is associated with a reduction of pregnancy complications, especially in obese women, but some concern remains, because metformin crosses the placenta, and it is associated with a significantly lower mean birth weight than insulin. In the elderly, gastrointestinal tolerability and renal function must be reassessed more often. Vitamin B-12 should be screened regularly in long-time metformin users because metformin may induce clinical vitamin B-12 deficiency.

Proteomic Profiling Identifies Distinct Regulation of Proteins in Obese Diabetic Patients Treated with Metformin

Background: Obesity and type 2 diabetes mellitus (T2DM) are characterized by underlying low-grade chronic inflammation. Metformin has been used as the first line of therapy in T2DM as it decreases hepatic glucose production and glucose intestinal absorption, enhances insulin sensitivity and weight loss, and is known to ameliorate inflammation. The mechanisms through which metformin exerts its effect remain unclear. Proteomics has emerged as a unique approach to explore the biological changes associated with diseases, including T2DM. It provides insight into the circulating biomarkers/mediators which could be utilized for disease screening, diagnosis, and prognosis. Methods: This study evaluated the proteomic changes in obese (Ob), obese diabetics (OD), and obese diabetic patients on metformin (ODM) using a 2D DIGE MALDI-TOF mass spectrometric approach. Results: Significant changes in sixteen plasma proteins (15 up and 1 down, ANOVA, p ≤ 0.05; fold change ≥ 1.5) were observed in the ODM group when compared to the Ob and OD groups. Bioinformatic network pathway analysis revealed that the majority of these altered plasma proteins are involved in distinct pathways involving acute-phase response, inflammation, and oxidative response and were centered around HNF4A, ERK, JNK, and insulin signaling pathways. Conclusions: Our study provides important information about the possible biomarkers altered by metformin treatment in obese patients with and without T2DM. These altered plasma proteins are involved in distinct pathways involving acute-phase response, inflammation, and oxidative response and were centered around HNF4A, ERK, JNK, and insulin signaling pathways. The presented proteomic profiling approach may help in identifying potential biomarkers/mediators affected by metformin treatment in T2DM and inform the understanding of metformin's mechanisms of action.

Cardiometabolic effects of SGLT2 inhibitors on polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrinopathy affecting many women of reproductive age. Although its physiology is poorly understood, hyperandrogenemia and insulin resistance play a pivotal role in this complex syndrome, predisposing patients to a variety of cardiovascular and metabolic modalities. Current therapeutic options, including lifestyle modifications and medications, often do not satisfactorily improve clinical outcomes. SGLT2 inhibitors (SGLT-2i) are a novel option which can potentially improve many hormonal and metabolic parameters for patients with PCOS, though the net cardiovascular effects remain under investigation in this population of patients with PCOS. Overall, the use of SGLT-2i may be associated with beneficial somatometric, metabolic and hormonal outcomes of PCOS. To date, all available studies have recorded body mass index, waist and hip circumference, and fat mass reductions, improved insulin and androgen levels, and reduced blood pressure. The aim of the present review is to summarise PCOS-related manifestations and mechanisms leading to cardiovascular disease, to explore the cardiometabolic impact of SGLT2i on PCOS, and to critically analyse the cardiometabolic and hormonal outcomes of the recent studies on the use of SGLT2i in women with PCOS.

Effect of Human Adenovirus 36 on Response to Metformin Monotherapy in Obese Mexican Patients with Type 2 Diabetes: A Prospective Cohort Study

Human adenovirus 36 (HAdV-36) has been associated with obesity and changes in glucose and lipid metabolism. The virus has been reported to increase insulin sensitivity and paradoxically promote weight gain. Because of its effects on metabolism, infection with the virus could alter the response to several drugs used to treat type 2 diabetes (DM2), such as metformin. The aim of this study was to test whether HAdV-36 affects the response to metformin in a group of obese patients with DM2.

METHODS

In a prospective cohort study, 103 obese patients with newly diagnosed DM2 were divided into two groups based on their HAdV-36 seropositivity (+HAdV-36 and -HAdV-36). Weight, glucose, cholesterol, triglycerides, body mass index, body fat percentage, and waist and hip circumference were measured and compared in both groups at baseline and after 45 days of metformin treatment.

RESULTS

Only glucose was significantly lower in the +HAdV-36 group at baseline, while all other variables were similar between the two study groups. After 45 days of follow-up, it was observed that the effect of metformin did not differ between the groups, but the variables improved significantly after treatment.

CONCLUSIONS

In this study, we did not find that HAdV-36 had an effect on the response to metformin in obese patients with DM2.

Management of hyperglycaemia in people with obesity

Diabetes and obesity are closely interlinked. Obesity is a major risk factor for the development of type 2 diabetes mellitus and appears to be an important risk factor for diabetic micro- and macrovascular complications. Management of hyperglycaemia in people with diabetes is important to reduce diabetes-related complications. Previously, there was a significant tension between management of hyperglycaemia and mitigating weight gain. Older drugs, such as sulfonylureas, glitazones, and insulin, although effective antihyperglycaemic agents, tend to induce weight gain. There is now an increasing recognition in people with obesity and diabetes that the focus should be on aiding weight loss, initially with improvements in diet and physical activity, possibly with the use of low-calorie diet programmes. Subsequent addition of metformin and newer agents, such as sodium-glucose transporter-2 inhibitors and glucagon-like peptide-1 analogues, will aid glucose control and weight reduction, and offer cardiovascular and renal protection. These drugs are now much higher in the therapeutic pathway in many national and international guidelines. Bariatric surgery may also be an effective way to manage hyperglycaemia or induce remission in individuals with both obesity and diabetes.

Metformin: A Review of Potential Mechanism and Therapeutic Utility Beyond Diabetes

Metformin has been designated as one of the most crucial first-line therapeutic agents in the management of type 2 diabetes mellitus. Primarily being an antihyperglycemic agent, metformin also has a plethora of pleiotropic effects on various systems and processes. It acts majorly by activating AMPK (Adenosine Monophosphate-Activated Protein Kinase) in the cells and reducing glucose output from the liver. It also decreases advanced glycation end products and reactive oxygen species production in the endothelium apart from regulating the glucose and lipid metabolism in the cardiomyocytes, hence minimizing the cardiovascular risks. Its anticancer, antiproliferative and apoptosis-inducing effects on malignant cells might prove instrumental in the malignancy of organs like the breast, kidney, brain, ovary, lung, and endometrium. Preclinical studies have also shown some evidence of metformin's neuroprotective role in Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Metformin exerts its pleiotropic effects through varied pathways of intracellular signalling and exact mechanism in the majority of them remains yet to be clearly defined. This article has extensively reviewed the therapeutic benefits of metformin and the details of its mechanism for a molecule of boon in various conditions like diabetes, prediabetes, obesity, polycystic ovarian disease, metabolic derangement in HIV, various cancers and aging.

Role of obesity related inflammation in pathogenesis of peripheral artery disease in patients of type 2 diabetes mellitus

Objective

Type 2 diabetes mellitus (T2DM) has emerged as one of the greatest global health challenges of twenty-first century. Visceral obesity is one of the most important determinant of insulin resistance (IR) as well as T2DM complications. Therefore this review focuses on the molecular mechanism of obesity induced inflammation, signaling pathways contributing to diabetes, as well as role of lifestyle interventions and medical therapies in the prevention and management of T2DM.

Method

Articles were searched on digital data base PubMed, Cochrane Library, and Web of Science. The key words used for search included Type 2 diabetes mellitus, obesity, insulin resistance, vascular inflammation and peripheral arterial disease.

Result

Visceral obesity is associated with chronic low grade inflammation and activation of immune systems which are involved in pathogenesis of obesity related IR and T2DM.

Conclusion

Metabolic dysregulation of adipose tissue leads to local hypoxia, misfolded/unfolded protein response and increased circulating free fatty acids, which in turn initiate inflammatory signaling cascades in the population of infiltrating cells. Mechanism that relates the role of adipocytokines with insulin sensitivity and glucose homeostasis might throw a light on the development of therapeutic interventions and subsequently might result in the reduction of vascular complications.

Non-Nutritive Sweetened Beverages Impair Therapeutic Benefits of Metformin in Prediabetic Diet-Induced Obese Mice

Metformin, a frontline therapy for type 2 diabetes and related metabolic diseases, results in variable outcomes. This study aimed to investigate whether sweetened beverages (caloric or non-caloric) affect the therapeutic benefits of metformin on glucose, food intake, and weight loss in diet-induced obesity. Mice were given a high-fat diet and sweetened water for 8 weeks to induce obesity and glucose intolerance. Then, mice were randomized to receive metformin in either water, high-fructose corn syrup (HFCS), or the non-nutritive sweetener saccharin for 6 weeks. After 6 weeks of metformin treatment, all groups had improved glucose tolerance compared to pretreatment. However, saccharin resulted in worse glucose tolerance and weight gain outcomes than the water or HFCS groups and correlated with lower plasma growth differentiation factor 15 levels. In conclusion, reducing non-nutritive sweetener consumption during metformin therapy is recommended to avoid impairing the therapeutic effects of metformin on body weight and glucose homeostasis.

DPP-4 inhibitors for treating T2DM - hype or hope? an analysis based on the current literature

DPP-4 inhibition is an interesting line of therapy for treating Type 2 Diabetes Mellitus (T2DM) and is based on promoting the incretin effect. Here, the authors have presented a brief appraisal of DPP-4 inhibitors, their modes of action, and the clinical efficiency of currently available drugs based on DPP-4 inhibitors. The safety profiles as well as future directions including their potential application in improving COVID-19 patient outcomes have also been discussed in detail. This review also highlights the existing queries and evidence gaps in DPP-4 inhibitor research. Authors have concluded that the excitement surrounding DPP-4 inhibitors is justified because in addition to controlling blood glucose level, they are good at managing risk factors associated with diabetes.

Metformin: evidence from preclinical and clinical studies for potential novel applications in cardiovascular disease

INTRODUCTION

For a long time, metformin has been the first-line treatment for glycaemic control in type 2 diabetes, however, the results of recent cardiovascular outcome trials of sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1 receptor agonists have caused many to question metformin's position in the guidelines. Although there are several plausible mechanisms by which metformin might have beneficial cardiovascular effects, for example its anti-inflammatory effects and metabolic properties, and numerous observational data suggesting improved cardiovascular outcomes with metformin use, the main randomised clinical trial data for metformin was published over 20 years ago. Nevertheless, the overwhelming majority of participants in contemporary type 2 diabetes trials were prescribed metformin.

AREAS COVERED

In this review we will summarise the potential mechanisms of cardiovascular benefit with metformin, before discussing clinical data in individuals with or without diabetes.

EXPERT OPINION

Metformin may have some cardiovascular benefit in patients with and without diabetes, however the majority of clinical trials were small and are before the use SGLT2 inhibitors and GLP1-RAs. Larger contemporary randomised trials with metformin evaluating its cardiovascular benefit are warranted.

Diabetes and Risk of Hepatocellular Carcinoma in Cirrhosis Patients with Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the world. NAFLD is a hepatic manifestation of insulin resistance, the core pathophysiology of diabetes. Multiple clinical studies show that diabetes increases the risk of liver disease progression and cirrhosis development in patients with NAFLD. Diabetes has causal associations with many different cancers, including hepatocellular carcinoma (HCC). More recent studies demonstrate that diabetes increases the risk of HCC in patients with underlying NAFLD cirrhosis, confirming the direct hepatocarcinogenic effect of diabetes among cirrhosis patients. Diabetes promotes hepatocarcinogenesis via the activation of inflammatory cascades producing reactive oxygen species and proinflammatory cytokines, leading to genomic instability, cellular proliferation, and inhibition of apoptosis. Given the global increase in the burden of NAFLD and HCC, high-risk patients such as older diabetic individuals should be carefully monitored for HCC development. Future larger studies should explore whether the effect of diabetes on HCC risk in NAFLD cirrhosis is modifiable by the type of antidiabetic medication and the effectiveness of diabetes control.

Antioxidant, antihyperglycemic, and antihyperlipidemic properties of Chimonanthus salicifolius S. Y. Hu leaves in experimental animals: modulation of thioredoxin and glutathione systems, renal water reabsorption, and gut microbiota

Introduction

Excessive calorie intake and physical inactivity have dramatically increased nutrient overload-associated disease, becoming a global public health issue. Chimonanthus salicifolius S. Y. Hu (CHI) is a homology plant of food and medicine in China and shows several health benefits.

Methods

This work investigated the antioxidant activity, the alleviating effects, and the mechanism of action on diabetes and hyperlipidemia of CHI leaves.

Results and discussion

Results showed that CHI leaves infusion displayed in vitro antioxidant activity measured by ABTS and ferric reducing antioxidant power methods. In wild-type Kunming mice, CHI leaves infusion consumption activated the hepatic antioxidant enzymes, including glutathione reductase, glutathione S-transferase, glutathione peroxidase and thioredoxin reductase as well as thioredoxin reductase 1. In alloxan-induced type 1 diabetic mice, CHI leaves infusion ameliorated diabetic symptoms, including polyuria, polydipsia, polyphagia and hyperglycemia, in a dose-dependent and time-course manners. The mechanism involved CHI leaves up-regulating renal water reabsorption associated protein - urine transporter A1-and promoting the trafficking of urine transporter A1 and aquaporin 2 to the apical plasma membrane. Despite this, in high-fat diet-induced hyperlipidemic golden hamsters, CHI leaves powder did not significantly effect on hyperlipidemia and body weight gain. This might be attributed to CHI leaves powder increasing the calorie intake. Interestingly, we found that CHI leaves extract containing a lower dose of total flavonoid than CHI leaves powder pronouncedly reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in serum in golden hamsters fed a high-fat diet. Furthermore, CHI leaves extract elevated the diversity of gut microbiota and the abundance of Bifidobacterium and Ruminococcaceae_UCG-014. It also decreased the abundance of Lactobacillus at the genus level in golden hamsters fed a high-fat diet. Overall, CHI leaves benefit oxidative stress prevention and metabolic syndrome amelioration in vivo.

Metformin in therapeutic applications in human diseases: its mechanism of action and clinical study

Metformin, a biguanide drug, is the most commonly used first-line medication for type 2 diabetes mellites due to its outstanding glucose-lowering ability. After oral administration of 1 g, metformin peaked plasma concentration of approximately 20-30 μM in 3 h, and then it mainly accumulated in the gastrointestinal tract, liver and kidney. Substantial studies have indicated that metformin exerts its beneficial or deleterious effect by multiple mechanisms, apart from AMPK-dependent mechanism, also including several AMPK-independent mechanisms, such as restoring of redox balance, affecting mitochondrial function, modulating gut microbiome and regulating several other signals, such as FBP1, PP2A, FGF21, SIRT1 and mTOR. On the basis of these multiple mechanisms, researchers tried to repurpose this old drug and further explored the possible indications and adverse effects of metformin. Through investigating with clinical studies, researchers concluded that in addition to decreasing cardiovascular events and anti-obesity, metformin is also beneficial for neurodegenerative disease, polycystic ovary syndrome, aging, cancer and COVID-19, however, it also induces some adverse effects, such as gastrointestinal complaints, lactic acidosis, vitamin B12 deficiency, neurodegenerative disease and offspring impairment. Of note, the dose of metformin used in most studies is much higher than its clinically relevant dose, which may cast doubt on the actual effects of metformin on these disease in the clinic. This review summarizes these research developments on the mechanism of action and clinical evidence of metformin and discusses its therapeutic potential and clinical safety.

Glucose-lowering drugs with cardiovascular benefits as modifiers of critical elements of the human life history

The life history theory assumes that all organisms are under selective pressure to harvest external resources and allocate them to maximise fitness: only organisms making the best use of energy obtain the greatest fitness benefits. The trade-off of energy spans four functions: maintenance, growth, reproduction, and defence against pathogens. The innovative antihyperglycaemic agents glucagon-like peptide 1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors decrease bodyweight and have the potential to counter low-grade inflammation. These key activities could rewire two components of the life history theory operative in adulthood-ie, maintenance and defence. In this Personal View, we postulate that the benefits of these medications on the cardiovascular system, beyond their glucose-lowering effects, could be mediated by the reduction of the maintenance cost driven by obesity and efforts spent on blunting low-grade inflammation.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

Effect of metformin on nonalcoholic fatty liver based on meta-analysis and network pharmacology

BACKGROUND

Whether metformin is related to nonalcoholic fatty liver disease (NAFLD) is controversial. Our aim was to investigate the relationship between metformin and NAFLD that may predict the metformin potential of these lesions and new prevention strategies in NAFLD patients.

METHODS

The meta-analysis was analyzed by Revman 5.3 softwares systematically searched for works published through July 29, 2022. Network pharmacology research based on databases, Cytoscape 3.7.1 software and R software respectively.

RESULTS

The following variables were associated with metformin in NAFLD patients: decreased of alanine aminotransferase (ALT) level (mean difference [MD] = -10.84, 95% confidence interval [CI] = -21.85 to 0.16, P = .05); decreased of aspartate amino transferase (AST) level (MD = -4.82, 95% CI = -9.33 to -0.30, P = .04); decreased of triglyceride (TG) level (MD = -0.17, 95% CI = -0.26 to -0.08, P = .0002); decreased of total cholesterol (TC) level (MD = -0.29, 95% CI = -0.47 to -0.10, P = .003); decreased of insulin resistance (IR) level (MD = -0.42, 95% CI = -0.82 to -0.02, P = .04). In addition, body mass index (BMI) (MD = -0.65, 95% CI = -1.46 to 0.16, P = .12) had no association with metformin in NAFLD patients. 181 metformin targets and 868 NAFLD disease targets were interaction analyzed, 15 core targets of metformin for the treatment of NAFLD were obtained. The effect of metformin on NAFLD mainly related to cytoplasm and protein binding, NAFLD, hepatitis B, pathway in cancer, toll like receptor signaling pathway and type 2 diabetes mellitus (T2DM). The proteins of hypoxia inducible factor-1 (HIF1A), nuclear factor erythroid 2-related factor (NFE2L2), nitric oxide synthase 3 (NOS3), nuclear receptor subfamily 3 group C member 1 (NR3C1), PI3K catalytic subunit alpha (PIK3CA), and silencing information regulator 2 related enzyme 1 (SIRT1) may the core targets of metformin for the treatment of NAFLD.

CONCLUSION

Metformin might be a candidate drug for the treatment of NAFLD which exhibits therapeutic effect on NAFLD patients associated with ALT, AST, TG, TC and IR while was not correlated with BMI. HIF1A, NFE2L2, NOS3, NR3C1, PIK3CA, and SIRT1 might be core targets of metformin for the treatment of NAFLD.

Medical treatment of weight loss in children and adolescents with obesity

Obesity remains one of the biggest health problems both in adults and children. Lifestyle modification, including diet and exercise, continues to be the mainstay of obesity prevention and treatment. Unfortunately, lifestyle modifications are often unsuccessful. Pharmacological treatment of obesity in pediatric patients can be applied in selected cases, and not before evidence of failure of the multidisciplinary lifestyle intervention. In this narrative review, we revised the most up-to-date evidence on medical treatment of weight loss in children and adolescents with obesity, including FDA- or EMA-approved and -experimented, not approved, drugs for pediatric population. Multidisciplinary treatment of childhood obesity, regulation of appetite control, energy balance and body weight were also discussed, in order to clarify the indications and mechanism action of drugs. Despite a substantial number of medications used for the treatment of obesity in adults, a limited number of drugs are approved by the drug regulatory agencies for pediatric population. Further research is needed to evaluate the efficacy and safety of novel pharmacological approaches for treatment of pediatric obesity in order to optimize weight management for children and adolescents and limit the development obesity-related comorbidities.

Metformin use and the risk of total knee replacement among diabetic patients: a propensity-score-matched retrospective cohort study

Metformin has been shown to modulate meta-inflammation, an important pathogenesis in knee osteoarthritis (OA). The study aimed to test the association between regular metformin use with total knee replacement (TKR) in patients with diabetes. This is a retrospective study with electronic records retrieved in Hong Kong public primary care. Patients with diabetes aged ≥ 45 who visited during 2007 to 2010, were followed up for a four-year period from 2011 to 2014 to determine the incidence of TKR. Propensity score matching based on age, sex, co-medications and chronic conditions was conducted to adjust for confounding. Cox regression was implemented to examine the association between metformin use and TKR. In total, 196,930 patients were eligible and 93,330 regular metformin users (defined as ≥ 4 prescriptions over the previous year) and non-users were matched. Among 46,665 regular users, 184 TKRs were conducted, 17.1% fewer than that among non-users. Cox regression showed that regular metformin users had a 19%-lower hazard of TKR [hazard ratio (HR) = 0.81, 95% confidence interval: 0.67 to 0.98, P = 0.033], with a dose–response relationship. Findings suggest a potential protective effect of metformin on knee OA progression and later TKR incidence among diabetic patients.

The Mechanism of Action of Biguanides: New Answers to a Complex Question

Biguanides are a family of antidiabetic drugs with documented anticancer properties in preclinical and clinical settings. Despite intensive investigation, how they exert their therapeutic effects is still debated. Many studies support the hypothesis that biguanides inhibit mitochondrial complex I, inducing energy stress and activating compensatory responses mediated by energy sensors. However, a major concern related to this “complex” model is that the therapeutic concentrations of biguanides found in the blood and tissues are much lower than the doses required to inhibit complex I, suggesting the involvement of additional mechanisms. This comprehensive review illustrates the current knowledge of pharmacokinetics, receptors, sensors, intracellular alterations, and the mechanism of action of biguanides in diabetes and cancer. The conditions of usage and variables affecting the response to these drugs, the effect on the immune system and microbiota, as well as the results from the most relevant clinical trials in cancer are also discussed.

Synthesis, characterization and evaluation of in vitro antimicrobial and anti-diabetic activity of berberine encapsulated in guar-acacia gum nanocomplexes

In the present study, the anti-diabetic and antimicrobial properties of berberine were improved using non-ionic guar gum and ionic acacia gum as nanocarriers. Berberine loaded guar-acacia gum nanocomplexes were synthesized by employing ionic complexation method. The formulation was characterized by dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and evaluated for in vitro dissolution study, anti-diabetic activity and antimicrobial activity. The optimized berberine loaded guar-acacia gum nanocomplexes had a particle size of 290.2 nm as indicated by DLS and drug entrapment efficiency of 96.5%. Morphological analysis revealed that berberine nanocomplexes were spherical-shaped with a smooth surface and size in the range of 100–250 nm. Moreover, berberine loaded guar-acacia nanocomplexes showed good stability and controlled released property in vitro. Antimicrobial activity against bacterial strains and fungal strains demonstrated the higher antimicrobial potential of berberine loaded gum nanocomplexes than gum nanocomplexes (blank) and pure berberine as indicated by the greater zone of inhibition diameter. In vitro anti-diabetic assessment showed higher percentage inhibition of the α-amylase enzyme by berberine loaded gum nanocomplexes as compared to pure berberine and blank nanocomplexes. In conclusion, the improved biological potency of berberine upon encapsulation into gum nanocomplexes indicates that berberine loaded guar-acacia gum nanocomplexes can be used as a promising candidate against diabetes and pathogenic microorganisms in the near future.

Hypoglycaemic therapy in frail older people with type 2 diabetes mellitus-a choice determined by metabolic phenotype

Frailty is a newly emerging complication of diabetes in older people and increasingly recognised in national and international clinical guidelines. However, frailty remains less clearly defined and frail older people with diabetes are rarely characterised. The general recommendation of clinical guidelines is to aim for a relaxed glycaemic control, mainly to avoid hypoglycaemia, in this often-vulnerable group of patients. With increasing age and development of frailty, body composition changes are characterised by an increase in visceral adipose tissue and a decrease in body muscle mass. Depending on the overall body weight, differential loss of muscle fibre types and body adipose/muscle tissue ratio, the presence of any associated frailty can be seen as a spectrum of metabolic phenotypes that vary in insulin resistance of which we have defined two specific phenotypes. The sarcopenic obese (SO) frail phenotype with increased visceral fat and increased insulin resistance on one side of spectrum and the anorexic malnourished (AM) frail phenotype with significant muscle loss and reduced insulin resistance on the other. In view of these varying metabolic phenotypes, the choice of hypoglycaemic therapy, glycaemic targets and overall goals of therapy are likely to be different. In the SO phenotype, weight-limiting hypoglycaemic agents, especially the new agents of GLP-1RA and SGLT-2 inhibitors, should be considered early on in therapy due to their benefits on weight reduction and ability to achieve tight glycaemic control where the focus will be on the reduction of cardiovascular risk. In the AM phenotype, weight-neutral agents or insulin therapy should be considered early on due to their benefits of limiting further weight loss and the possible anabolic effects of insulin. Here, the goals of therapy will be a combination of relaxed glycaemic control and avoidance of hypoglycaemia; and the focus will be on maintenance of a good quality of life. Future research is still required to develop novel hypoglycaemic agents with a positive effect on body composition in frailty and improvements in clinical outcomes.

Cardio-respiratory and phenotypic rescue of dystrophin/utrophin-deficient mice by combination therapy

Duchenne muscular dystrophy (DMD) is a systemic progressive muscular disease caused by frame-disrupting mutations in the DMD gene. Although exon-skipping antisense oligonucleotides (AOs) are clinically approved and can correct DMD, insufficient muscle delivery limits efficacy. If AO activity can be enhanced by safe dietary supplements, clinical trials for efficacy can be undertaken rapidly to benefit patients. We showed previously that intravenous glycine enhanced phosphorodiamidate morpholino oligomer (PMO) delivery to peripheral muscles in mdx mice. Here, we demonstrate that the combination of oral glycine and metformin with intravenous PMO enhances PMO activity, dystrophin restoration, extends lifespan, and improves body-wide function and phenotypic rescue of dystrophin /utrophin double knock-out (DKO) mice without any overt adverse effects. The DKO mice treated with the combination without altering the approved administration protocol of PMO show improved cardio-respiratory and behavioral functions. Metformin and glycine individually are ineffective in DMD patients, but the combination of PMO with clinically-approved oral glycine and metformin might improve the efficacy of the treatment also in DMD patients. Our data suggest that this combination therapy might be an attractive therapy for DMD and potentially other muscle diseases requiring systemic treatment with AOs.

Metformin and the heart: Update on mechanisms of cardiovascular protection with special reference to comorbid type 2 diabetes and heart failure

Metformin has been in clinical use for the management of type 2 diabetes for more than 60 years and is supported by a vast database of clinical experience: this includes evidence for cardioprotection from randomised trials and real-world studies. Recently, the position of metformin as first choice glucose-lowering agent has been supplanted to some extent by the emergence of newer classes of antidiabetic therapy, namely the sodium-glucose co-transporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists. These agents have benefitted through support from large cardiovascular outcomes trials with more modern trial designs than earlier studies conducted to assess metformin. Nevertheless, clinical research on metformin continues to further assess its many potentially advantageous effects. Here, we review the evidence for improved cardiovascular outcomes with metformin in the context of the current era of diabetes outcomes trials. Focus is directed towards the potentially cardioprotective actions of metformin in patients with type 2 diabetes and heart failure (HF), now recognised as the most common complication of diabetes.

Managing weight and glycaemic targets in people with type 2 diabetes—How far have we come?

Introduction

As the vast majority of people with type 2 diabetes (T2D) are also overweight or obese, healthcare professionals (HCP) are faced with the task of addressing both weight management and glucose control. In this narrative review, we aim to identify the challenges of reaching and maintaining body weight targets in people with T2D and highlight current and future treatment interventions.

Methods

A search of the PubMed database was conducted using the search terms “diabetes” and “weight loss.”

Results

According to emerging evidence, treating obesity may be antecedent to the development and progression of T2D. While clinical benefits typically set in upon achieving a weight loss of 3–5%, these benefits are progressive leading to further health improvements, and weight loss of >15% can have a disease‐modifying effect in people with T2D, an outcome that up to recently could not be achieved with any blood glucose‐lowering pharmacotherapy. However, advanced treatment options with weight‐loss effects currently in development including the dual GIP/GLP‐1 receptor agonists may enable simultaneous achievement of individual glycemic and weight goals.

Conclusion

Despite considerable therapeutic progress, there is still a large unmet medical need in patients with T2D who miss their individualized glycemic and weight‐loss targets. Nonetheless, it is to be expected that development of future therapies and their use will favourably change the scenario of weight and glucose control in T2D.

Effect of Metformin on T2D-Induced MAM Ca2+ Uncoupling and Contractile Dysfunction in an Early Mouse Model of Diabetic HFpEF

Diabetic cardiomyopathy (DCM) is a leading complication in type 2 diabetes patients. Recently, we have shown that the reticulum-mitochondria Ca²⁺ uncoupling is an early and reversible trigger of the cardiac dysfunction in a diet-induced mouse model of DCM. Metformin is a first-line antidiabetic drug with recognized cardioprotective effect in myocardial infarction. Whether metformin could prevent the progression of DCM remains not well understood. We therefore investigated the effect of a chronic 6-week metformin treatment on the reticulum-mitochondria Ca²⁺ coupling and the cardiac function in our high-fat high-sucrose diet (HFHSD) mouse model of DCM. Although metformin rescued the glycemic regulation in the HFHSD mice, it did not preserve the reticulum-mitochondria Ca²⁺ coupling either structurally or functionally. Metformin also did not prevent the progression towards cardiac dysfunction, i.e., cardiac hypertrophy and strain dysfunction. In summary, despite its cardioprotective role, metformin is not sufficient to delay the progression to early DCM.

The effect of metformin on body mass index and metabolic parameters in non-diabetic HIV-positive patients: a meta-analysis

We sought to evaluate the effetc of metformin on body mass index (BMI) and metabolic parameters in HIV-positive patients. We performed a comprehensive search through five major indexing databases, using keywords ("metformin" OR "dimethylguanylguanidine" OR "biguanide" OR "Glucophage") AND ("HIV" OR "human immunodeficiency virus" OR "AIDS" OR "Acquired immunodeficiency syndrome"), and all possible combinations until January 15, 2021. We measured standardized mean differences (SMD) and 95% confidence intervals (CI) for each outcome. We finally included 12 RCTs (577 participants, 274 in the metformin group and 303 in the comparators). Metformin did not significantly change BMI index compared to various comparators. Metformin generally improve LDL levels (SMD = 0.29, 95% CI: - 1.00 1.57, P = 0.01), HDL levels (SMD = - 0.15, 95% CI: - 0.72 0.41, P = 0.001), triglycerides values (SMD = 0.46, 95% CI: - 0.36 1.27, P < 0.00001), fasting glucose (SMD = - 0.82, 95% CI: - 1.80 0.15, P < 0.00001), insulin 120 min (SMD = - 0.82, 95% CI: - 1.59-0.04, P = 0.02), and glucose 120 min (SMD = - 1.24, 95% CI: - 2.57 0.10, P < 0.0001), but worsened total cholesterol values (SMD = 1.24, 95% CI: - 0.98 3.46, P = 0.0001). Metformin is safe for weight loss in obese people; however, this drug may not be suitable for everyone, especially those who are not overweight. Nevertheless the body of evidences may suggest that metformin had promising impacts on metabolic parameters in patients with both HIV, it is still unknown that such surrogate changes will translate to long-standing clinical advantages.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00869-1.

Treating the Chronic Disease of Obesity

Obesity is a treatable chronic disease. Primary care providers play an essential role in diagnosis, treatment, and comprehensive care of patients with obesity. In recent years, treatment approaches have rapidly evolved, increasing effective and safe therapies. In this review, we provide practical information on the care of patients with obesity with a focus on antiobesity pharmacotherapy within the context of currently available therapeutic modalities such as intensive lifestyle interventions and bariatric surgery.

Beneficial effects of a plant-fish oil, slow carbohydrate diet on cardio-metabolic health exceed the correcting effects of metformin-pioglitazone in diabetic pigs fed a fast-food diet

Background

Lifestyle influences endocrine, metabolic and cardiovascular homeostasis. This study investigated the impact of diet and oral anti-diabetic medication on cardio-metabolic health in human-sized diabetic pigs.

Methods

After a growing pre-phase from ~30 to ~69 kg during which domestic pigs were fed either a low fat, low sucrose diet (group A) or a fast food-type diet elevated in lard (15%) and sucrose (40%) (group B), the pigs were subdivided in 5 groups (n = 7–8 pigs per group). Group 1, normal pigs from group A on a low fat, low sugar (L) pig diet and group 2, normal pigs from group B on a high lard (25%), sucrose-fructose (40%), cholesterol (1%) fast food-type (F) diet. Diabetes (D) was induced in group B pigs by streptozotocin and group 3 received the F diet (DF), group 4 received the F diet with Anti-diabetic medication metformin (2 g.day^-1)-pioglitazone (40 mg.day^-1) (DFA) and group 5 switched to a Plant-Fish oil (25%), Slowly digestible starch (40%) diet (DPFS). The F and PFS diets were identical for fat, carbohydrate and protein content but only differed in fat and carbohydrate composition. The 5 pig groups were followed up for 7 weeks until reaching ~120 kg.

Results

In normal pigs, the F diet predisposed to several abnormalities related to metabolic syndrome. Diabetes amplified the inflammatory and cardiometabolic abnormalities of the F diet, but both oral FA medication and the PFS diet partially corrected these abnormalities (mean±SEM) as follows: Fasting plasma TNF-ɑ (pg.ml^-1) and NEFA (mmol.l^-1) concentrations were high (p<0.02) in DF (193±55 and 0.79±0.16), intermediate in DFA (136±40 and 0.57±012) and low in DPFS pigs (107±31 and 0.48±0.19). Meal intolerance (response over fasting) for glucose and triglycerides (area under the curve, mmol.h^-1) and for lactate (3-h postprandial, mmol.l^-1) was high (p<0.03) in DF (489±131, 8.6±4.8 and 2.2±0.6), intermediate in DFA (276±145, 1.4±1.1 and 1.6±0.4) and low in DPFS (184±62, 0.7±1.8 and 0.1±0.1). Insulin-mediated glucose disposal (mg.kg^-1.min^-1) showed a numerical trend (p = NS): low in DF (6.9±2.2), intermediate in DFA (8.2±1.3) and high in DPFS pigs (10.4±2.7). Liver weight (g.kg^-1 body weight) and liver triglyceride concentration (g.kg^-1 liver) were high (p<0.001) in DF (23.8±2.0 and 69±14), intermediate in DFA (21.1±2.0 and 49±15) and low in DPFS pigs (16.4±0.7 and 13±2.0). Aorta fatty streaks were high (p<0.01) in DF (16.4±5.7%), intermediate in DFA (7.4±4.5%) and low in DPFS pigs (0.05±0.02%).

Conclusion

This translational study using pigs with induced type 2 diabetes provides evidence that a change in nutritional life style from fast food to a plant-fish oil, slowly digestible starch diet can be more effective than sole anti-diabetic medication.

Anti-diabetic drugs and weight loss in patients with type 2 diabetes

INTRODUCTION

Obesity is frequently a comorbidity of type 2 diabetes. Even modest weight loss can significantly improve glucose homeostasis and lessen cardiometabolic risk factors in patients with type 2 diabetes, but lifestyle-based weight loss strategies are not long-term effective. There is an increasing need to consider pharmacological approaches to assist weight loss in the so called diabesity syndrome. Aim of this review is to analyze the weight-loss effect of non-insulin glucose lowering drugs in patients with type 2 diabetes.

MATERIAL AND METHODS

A systematic analysis of the literature on the effect of non-insulin glucose lowering drugs on weight loss in patients with type 2 diabetes was performed. For each class of drugs, the following parameters were analyzed: kilograms lost on average, effect on body mass index and body composition.

RESULTS

Our results suggested that anti-diabetic drugs can be stratified into 3 groups based on their efficacy in weight loss: metformin, acarbose, empagliflozin and exenatide resulted in a in a mild weight loss (less than 3.2% of initial weight); canagliflozin, ertugliflozin, dapagliflozin and dulaglutide induces a moderate weight loss (between 3.2% and 5%); liraglutide, semaglutide and tirzepatide resulted in a strong weight loss (greater than 5%).

CONCLUSIONS

This study shows that new anti-diabetic drugs, particularly GLP1-RA and Tirzepatide, are the most effective in inducing weight loss in patients with type 2 diabetes. Interestingly, exenatide appears to be the only GLP1-RA that induces a mild weight loss.

Metformin doses to ensure efficacy and safety in patients with reduced kidney function

We aimed to develop a metformin dosing strategy to optimise efficacy and safety in patients with reduced kidney function. Metformin data from two studies stratified by kidney function were analysed. The relationship between metformin clearance and kidney function estimates was explored using a regression analysis. The maintenance dose range was predicted at different bands of kidney function to achieve an efficacy target of 1 mg/L for steady-state plasma concentrations. The dosing strategy was evaluated using simulations from a published metformin pharmacokinetic model to determine the probability of concentrations exceeding those associated with lactic acidosis risk, i.e. a steady-state average concentration of 3 mg/L and a maximum (peak) concentration of 5 mg/L. A strong relationship between metformin clearance and estimated kidney function using the Cockcroft and Gault (r2 = 0.699), MDRD (r2 = 0.717) and CKD-Epi (r2 = 0.735) equations was found. The probability of exceeding the safety targets for plasma metformin concentration was <5% for most doses and kidney function levels. The lower dose of 500 mg daily was required to maintain concentrations below the safety limits for patients with an eGFR of 15-29 mL/min. Our analysis suggests that a maximum daily dose of 2250, 1700, 1250, 1000, and 500 in patients with normal kidney function, CKD stage 2, 3a, 3b and 4, respectively, will provide a reasonable probability of achieving efficacy and safety. Our results support the cautious of use metformin at appropriate doses in patients with impaired kidney function.

Metformin as adjunctive therapy for dengue in overweight and obese patients: a protocol for an open-label clinical trial (MeDO)

Background:  Dengue is a disease of major global importance. While most symptomatic infections are mild, a small proportion of patients progress to severe disease with risk of hypovolaemic shock, organ dysfunction and death.  In the absence of effective antiviral or disease modifying drugs, clinical management is solely reliant on supportive measures. Obesity is a growing problem among young people in Vietnam and is increasingly recognised as an important risk factor for severe dengue, likely due to alterations in host immune and inflammatory pathways. Metformin, a widely used anti-hyperglycaemic agent with excellent safety profile, has demonstrated potential as a dengue therapeutic in vitro and in a retrospective observational study of adult dengue patients with type 2 diabetes.  This study aims to assess the safety and tolerability of metformin treatment in overweight and obese dengue patients, and investigate its effects on several clinical, immunological and virological markers of disease severity. Methods: This open label trial of 120 obese/overweight dengue patients will be performed in two phases, with a metformin dose escalation if no safety concerns arise in phase one. The primary endpoint is identification of clinical and laboratory adverse events.  Sixty overweight and obese dengue patients aged 10-30 years will be enrolled at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Participants will complete a 5-day course of metformin therapy and be compared to a non-treated group of 60 age-matched overweight and obese dengue patients. Discussion:  Previously observed antiviral and immunomodulatory effects of metformin make it a promising dengue therapeutic candidate in appropriately selected patients. This study will assess the safety and tolerability of adjunctive metformin in the management of overweight and obese young dengue patients, as well as its effects on markers of viral replication, endothelial dysfunction and host immune responses.  Trial registration: ClinicalTrials.gov: NCT04377451 (May 6 th 2020).

Metformin as adjunctive therapy for dengue in overweight and obese patients: a protocol for an open-label clinical trial (MeDO)

Background:  Dengue is a disease of major global importance. While most symptomatic infections are mild, a small proportion of patients progress to severe disease with risk of hypovolaemic shock, organ dysfunction and death.  In the absence of effective antiviral or disease modifying drugs, clinical management is solely reliant on supportive measures. Obesity is a growing problem among young people in Vietnam and is increasingly recognised as an important risk factor for severe dengue, likely due to alterations in host immune and inflammatory pathways. Metformin, a widely used anti-hyperglycaemic agent with excellent safety profile, has demonstrated potential as a dengue therapeutic in vitro and in a retrospective observational study of adult dengue patients with type 2 diabetes.  This study aims to assess the safety and tolerability of metformin treatment in overweight and obese dengue patients, and investigate its effects on several clinical, immunological and virological markers of disease severity.

Methods: This open label trial of 120 obese/overweight dengue patients will be performed in two phases, with a metformin dose escalation if no safety concerns arise in phase one. The primary endpoint is identification of clinical and laboratory adverse events.  Sixty overweight and obese dengue patients aged 10-30 years will be enrolled at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Participants will complete a 5-day course of metformin therapy and be compared to a non-treated group of 60 age-matched overweight and obese dengue patients.

Discussion:  Previously observed antiviral and immunomodulatory effects of metformin make it a promising dengue therapeutic candidate in appropriately selected patients. This study will assess the safety and tolerability of adjunctive metformin in the management of overweight and obese young dengue patients, as well as its effects on markers of viral replication, endothelial dysfunction and host immune responses. 

Trial registration: ClinicalTrials.gov: NCT04377451 (May 6 ^th 2020).

Pilosocereus gounellei (Cactaceae) stem extract decreases insulin resistance, inflammation, oxidative stress, and cardio-metabolic risk in diet-induced obese mice

ETHNOPHARMACOLOGICAL RELEVANCE

Pilosocereus gounellei (xique-xique) is a popular cactus from Caatinga, traditionally used to counter inflammatory processes and indicated as a hypoglycemic agent. Previous studies have shown that mice treated orally with saline extract of P. gounellei stem (containing flavonoids and sugars) showed decreased serum lipid levels.

AIM OF THE STUDY

In this work, we evaluated whether this extract would have beneficial effects against hyperglycemia and inflammatory status related to obesity in mice fed a high-fat diet (HFD).

METHODS

Obese animals were treated daily per os with the extract (EXT; 125, 250, and 500 mg/kg), metformin (MET; 400 mg/kg), or saline solution (diet-induced obese, DIO) for 21 days. A group of non-obese animals served as the control. We evaluated lipid profile, glucose and insulin tolerance, atherogenic indices, histological alterations, cytokine levels, and oxidative stress in liver, muscle, and adipose tissue.

RESULTS

At the end of the experiment, mice from EXT groups showed lower body weight and total cholesterol, LDL-cholesterol, and triglycerides compared with the DIO group; in addition, HDL-cholesterol levels and glucose and insulin tolerance were similar to those of the control group. When compared with the DIO group, the extract-treated mice showed reduction in cardiac risk ratio, atherogenic coefficient, atherogenic index of plasma, and Castelli's Risk Index II; decrease in epididymal fat; reduction in steatosis, collagen deposition, and liver inflammation; lower serum levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 6, and monocyte chemoattractant protein-1); inhibited lipid peroxidation; and increased superoxide dismutase levels in liver, muscle, and adipose tissue.

CONCLUSION

The P. gounellei saline extract was able to improve physiological parameters of obese mice, which highlight the potential of this plant as source of compounds with biotechnological relevance for pharmaceutical industry.

Metformin Improves Biochemical and Pathophysiological Changes in Hepatocellular Carcinoma with Pre-Existed Diabetes Mellitus Rats

Hepatocellular carcinoma (HCC) is one of the world’s most widely recognized malignant tumors that accounts for 90% of all the primary liver cancers and is a major cause of death from cancer, representing half a million deaths per year. Obesity and associated metabolic irregularities, particularly diabetes mellitus (DM) and insulin resistance, are important risk factors for the advancement of HCC. Recently, retrospective studies showed that metformin (MET) could protect the hepatic tissues in pre-existing diabetes mellitus from HCC. The purpose of this study was to assess the role of MET treatment in the pre-existing diabetic rats before and after HCC induction by diethylnitrosamine (DEN). Thirty-five male Sprague Dawley albino rats were partitioned into the following groups: Group 1 (Gp1) was the control. Gp2 was injected intraperitoneally (i.p) with streptozotocin (STZ) (80 mg/kg) and DEN (50 mg/kg/7 weeks). Gp3, Gp4, and Gp5 were injected as in Gp2 and treated with MET (150 mg/kg) before and/or after HCC induction. Biochemical parameters including liver functions, lipid profile, and oxidative stress biomarkers were determined. Furthermore, histological and immunohistochemical changes were assessed in all groups. Our results illustrated that the group of rats that were treated with STZ and DEN had significant changes in both liver functions and were associated with alterations in the liver histopathological architectures. Treatment with MET before or after HCC induction ameliorated the cellular changes in the liver tissues; however, the utmost protection was found in a group of rats, which were treated with MET before and after HCC induction.

Where Does Metformin Stand in Modern Day Management of Type 2 Diabetes?

Metformin is the most commonly used glucose-lowering therapy (GLT) worldwide and remains the first-line therapy for newly diagnosed individuals with type 2 diabetes (T2D) in management algorithms and guidelines after the UK Prospective Diabetes Study (UKPDS) showed cardiovascular mortality benefits in the overweight population using metformin. However, the improved Major Adverse Cardiovascular Events (MACE) realised in some of the recent large cardiovascular outcomes trials (CVOTs) using sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have challenged metformin's position as a first-line agent in the management of T2D. Many experts now advocate revising the existing treatment algorithms to target atherosclerotic cardiovascular disease (ASCVD) and improving glycaemic control as a secondary aim. In this review article, we will revisit the major cardiovascular outcome data for metformin and include a critique of the UKPDS data. We then review additional factors that might be pertinent to metformin's status as a first-line agent and finally answer key questions when considering metformin's role in the modern-day management of T2D.

A randomized controlled trial of metformin on left ventricular hypertrophy in patients with coronary artery disease without diabetes: the MET-REMODEL trial

Aim

We tested the hypothesis that metformin may regress left ventricular hypertrophy (LVH) in patients who have coronary artery disease (CAD), with insulin resistance (IR) and/or pre-diabetes.

Methods and results

We randomly assigned 68 patients (mean age 65 ± 8 years) without diabetes who have CAD with IR and/or pre-diabetes to receive either metformin XL (2000 mg daily dose) or placebo for 12 months. Primary endpoint was change in left ventricular mass indexed to height^1.7 (LVMI), assessed by magnetic resonance imaging. In the modified intention-to-treat analysis (n = 63), metformin treatment significantly reduced LVMI compared with placebo group (absolute mean difference −1.37 (95% confidence interval: −2.63 to −0.12, P = 0.033). Metformin also significantly reduced other secondary study endpoints such as: LVM (P = 0.032), body weight (P = 0.001), subcutaneous adipose tissue (P = 0.024), office systolic blood pressure (BP, P = 0.022) and concentration of thiobarbituric acid reactive substances, a biomarker for oxidative stress (P = 0.04). The glycated haemoglobin A1C concentration and fasting IR index did not differ between study groups at the end of the study.

Conclusion

Metformin treatment significantly reduced LVMI, LVM, office systolic BP, body weight, and oxidative stress. Although LVH is a good surrogate marker of cardiovascular (CV) outcome, conclusive evidence for the cardio-protective role of metformin is required from large CV outcomes trials.

Osmolar-gap in the setting of metformin-associated lactic acidosis: Case report and a literature review highlighting an apparently unusual association

RATIONALE

Metformin-associated lactic acidosis (MALA) is a rare adverse effect that has significant morbidity and mortality. MALA is a high anion gap (AG), nonosmolar acidosis. Associated osmolar-gap (OG) is rarely reported, so finding an OG may make the diagnosis of MALA challenging.

PATIENT CONCERNS

Forty-five years' old type II diabetic patient on metformin presented to emergency with a two-day history of vomiting, watery diarrhea, and mild abdominal discomfort. On examinations, he looked dehydrated. Investigation revealed acute kidney injury (AKI) with a high lactic acid (LA) level of 24 mmol/L, pH of 6.8, AG of 40, and an OG of 20 mOsm/kg DIAGNOSES:: The presence of an OG made the diagnosis challenging; the history was negative for alcohol, osmolar substance, or illicit drug ingestion or use. The toxicology screen was negative. After ruling out plausible causes of AG and OG, MALA was deemed the likely reason for his presentation likely precipitated by dehydration and AKI.

INTERVENTIONS

He underwent two sessions of hemodialysis, afterward managed with fluid hydration.

OUTCOMES

On day 3, he was in the polyuric phase suggestive of acute tubular necrosis. His serum creatinine improved afterward with improved acidosis; after 8 days, he was discharged in stable condition.

LESSONS

MALA is a rare side effect of metformin therapy. Acute kidney injury is a known precipitant of MALA. In our review, we highlight the association of MALA and the presence of an OG. We believe that treating physicians should be aware of this relationship to avoid delaying or overlooking such an important diagnosis.

Association of pregnancy outcomes in women with type 2 diabetes treated with metformin versus insulin when becoming pregnant

BACKGROUND

Metformin use in pregnancy is controversial because metformin crosses the placenta and the safety on the fetus has not been well-established. This retrospective study aimed to compare pregnancy outcomes in women with preexisting type 2 diabetes receiving metformin or standard insulin treatment.

METHODS

The cohort of this population-based study includes women of age 20-44 years with preexisting type 2 diabetes and singleton pregnancies in Taiwan between 2003 and 2014. Subjects were classified into three mutually exclusive groups according to glucose-lowering treatments received before and after becoming pregnant: insulin group, switching group (metformin to insulin), and metformin group. A generalized estimating equation model adjusted for patient age, duration of type 2 diabetes, hypertension, hyperlipidemia, retinopathy, and aspirin use was used to estimate the adjusted odds ratio (aOR) and 95% confidence interval (CI) of adverse pregnancy outcomes.

RESULTS

A total of 1166 pregnancies were identified in the insulin group (n = 222), the switching group (n = 318) and the metformin group (n = 626). The insulin group and the switching group had similar pregnancy outcomes for both the mother and fetus, including risk of primary cesarean section, pregnancy-related hypertension, preeclampsia, preterm birth (< 37 weeks), very preterm birth (< 32 weeks), low birth weight (< 2500 g), high birth weight (> 4000 g), large for gestational age, and congenital malformations. The metformin group had a lower risk of primary cesarean section (aOR = 0.57; 95% CI, 0.40-0.82) and congenital malformations (aOR, 0.51; 95% CI; 0.27-0.94) and similar risk for the other outcomes as compared with the insulin group.

CONCLUSIONS

Metformin therapy was not associated with increased adverse pregnancy outcomes in women with type 2 diabetes as compared with standard insulin therapy.

Cardiovascular Effects of Hypoglycemic Agents in Diabetes Mellitus

BACKGROUND

Despite substantial improvements over the years, diabetes mellitus is still associated with cardiovascular disease, heart failure, and excess mortality.

OBJECTIVE

The objective of this article is to examine existing data on the reduction of cardiovascular morbidity and mortality in diabetes. Control of glycemia, lipid levels, and blood pressure are described in brief. The main scope of this article is, however, to review the glucose-independent cardiovascular effect of antidiabetic pharmacological agents (mainly other than insulin).

METHODS

The article is a narrative review based on recently published reviews and meta-analyses complemented with data from individual trials, when relevant.

RESULTS AND DISCUSSION

Older data suggest a cardioprotective role of metformin (an inexpensive and safe drug); a role to date not convincingly challenged. The cardiovascular effects of thiazolidinediones, sulphonylurea, and glinides are debatable. Recent large-scale cardiovascular outcome trials suggest a neutral profile of dipeptidyl peptidase 4 inhibitors, yet provide compelling evidence of cardioprotective effects of glucagon-like 1 receptor antagonists and sodium-glucose transporter 2 inhibitors.

CONCLUSION

Metformin may have a role in primary and secondary prevention of cardiovascular disease; glucagon-like 1 receptor antagonists and sodium-glucose co-transporter 2 inhibitors play a role in secondary prevention of atherosclerotic cardiovascular disease. Sodium-glucose transporter 2 inhibitors have a role to play in both primary and secondary prevention of heart failure; yet, they carry a small risk of the potentially dangerous adverse effect, euglycemic diabetic ketoacidosis.

Red Pepper (Capsicum annuum L.) Seed Extract Improves Glycemic Control by Inhibiting Hepatic Gluconeogenesis via Phosphorylation of FOXO1 and AMPK in Obese Diabetic db/db Mice

Obesity is a notable risk factor for developing type 2 diabetes, augmenting the concern of obese diabetes (ObD). Anti-obesity and antioxidant effects of red pepper seeds extract (RPSE) have increased our expectations that RPSE would also improve the pathological phenotypes of obese diabetes. Therefore, we hypothesized that RPSE would have an anti-diabetic effect in ObD mice. Animals were assigned either as follows: (1) db/+, (2) db/db control, (3) RPSE (200 mg/kg bw), or (4) a comparative control (metformin 150 mg/kg bw). RPSE was orally administered daily for 8 weeks. As a result, RPSE supplementation improved diabetic phenotypes, including fasting glucose, hemoglobin (HbA1c), and insulin levels. Pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6), and triglycerides were reduced in RPSE-treated mice. RPSE supplementation also diminished the rate-limiting enzymes of gluconeogenesis, including glucose 6-phosphatas (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), in the liver. RPSE supplementation increased the phosphorylation of forkhead box protein O1 (FOXO1) and AMP-activated protein kinase (AMPK), which underlined the mechanism of the anti-diabetic effects of RPSE. Taken together, RPSE has the potential to improve glycemic control by repressing hepatic gluconeogenesis via the phosphorylation of FOXO1 and AMPK in ObD mice.

Weight-centric pharmacological management of type 2 diabetes mellitus - An essential component of cardiovascular disease prevention

Obesity and overweight are contributing factors for diseases such as type 2 diabetes mellitus (T2DM), hypertension, hyperlipidemia, and ultimately, cardiovascular (CV) disease. Obesity is imposing an increasing health burden in rich and poor nations, with almost 30% of people globally now either obese or overweight - a staggering 2.1 billion. The link between obesity and T2DM is widely held to involve two adverse effects: obesity-induced insulin resistance and β-cell failure. This "unified field theory" raises questions about whether defects favoring progressive weight gain and metabolic impairment also contribute to β-cell decompensation. The concept of weight-centric management of T2DM is considered justified because of the strong negative impact of obesity on the effects of treatment of diabetes. Two pharmacotherapy options are considered: drugs developed primarily for blood glucose control that also exert a favorable effect on body weight and drugs developed primarily to induce weight loss that also have a favorable effect on glycemia. Treating hunger counter-regulatory mechanisms will have an additional effect on glucose control in T2DM. This narrative review addresses advances in pharmacotherapy for the management of obesity and obesity-related co-morbidities, with a focus on T2DM. It is also important to identify the correct balance between weight-centric and glucose-centric management of T2DM.

Metformin and cardiorenal outcomes in diabetes: A reappraisal

The guidance issued to the pharmaceutical industry by the US Food and Drug Administration in 2008 has led to the publication of a series of randomized, controlled cardiovascular outcomes trials with newer therapeutic classes of glucose-lowering medications. Several of these trials, which evaluated the newer therapeutic classes of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists, have reported a reduced incidence of major adverse cardiovascular and/or renal outcomes, usually relative to placebo and standard of care. Metformin was the first glucose-lowering agent reported to improve cardiovascular outcomes in the UK Prospective Diabetes Study (UKPDS) and thus became the foundation of standard care. However, as this clinical trial reported more than 20 years ago, differences from current standards of trial design and evaluation complicate comparison of the cardiovascular profiles of older and newer agents. Our article revisits the evidence for cardiovascular protection with metformin and reviews its effects on the kidney.

The Association between Metformin Therapy and Lactic Acidosis

INTRODUCTION AND OBJECTIVES

There is increasing evidence to suggest that therapeutic doses of metformin are unlikely to cause lactic acidosis. The aims of this research were (1) to formally evaluate the association between metformin therapy and lactic acidosis in published case reports using two causality scoring systems, (2) to determine the frequency of pre-existing independent risk factors in published metformin-associated lactic acidosis cases, (3) to investigate the association between risk factors and mortality in metformin-associated lactic acidosis cases, and (4) to explore the relationship between prescribed metformin doses, elevated metformin plasma concentrations and the development of lactic acidosis in cases with chronic renal impairment.

METHODS

A systematic review was conducted to identify metformin-associated lactic acidosis cases. Causality was assessed using the World Health Organisation-Uppsala Monitoring Centre system and the Naranjo adverse drug reaction probability scale. Compliance to dosing guidelines was investigated for cases with chronic renal impairment as well as the association between steady-state plasma metformin concentrations prior to admission.

RESULTS

We identified 559 metformin-associated lactic acidosis cases. Almost all cases reviewed (97%) presented with independent risk factors for lactic acidosis. The prescribed metformin dose exceeded published guidelines in 60% of cases in patients with impaired kidney function. Metformin steady-state plasma concentrations prior to admission were predicted to be below the proposed upper limit of the therapeutic range of 5 mg/L.

CONCLUSIONS

Almost all cases of metformin-associated lactic acidosis reviewed presented with independent risk factors for lactic acidosis, supporting the suggestion that metformin plays a contributory role. The prescribed metformin dose, on average, exceeded the dosing recommendations by 1000 mg/day in patients with varying degrees of renal impairment but the predicted pre-admission plasma concentrations did not exceed the therapeutic range.