Diabetes mellitus and increased risk of cancer: focus on metformin and the insulin analogs

Type 2 diabetes mellitus has been associated with an increased risk of hepatic, pancreatic, colon, endometrial, breast, and bladder cancer. Although a mechanism of action for the increased risk has been postulated, no definitive evidence has been completely elucidated in the medical literature. Results of recently released studies documented the use of specific antidiabetic drugs with increased rates of cancer. The insulin analog glargine was the focus of four observational studies published in 2009 that outlined an increase in the rates of cancer associated with its use. In contrast, the use of metformin has been shown to possibly decrease the rate of specific cancers when used in the treatment of type 2 diabetes. These data regarding cancer risk and antidiabetic drugs are contradictory and at this time are inconclusive. Until results of long-term randomized prospective studies are available to elucidate a correlation with cancer and insulin, we must continue treating diabetes in order to avert the long-term complications of the disease.     

New insights into antidiabetic drugs: Possible applications in cancer treatment

Globally at 2014, it was estimated that there was 347 million people with diabetes in which 90 percent of them were diagnosed with type 2 diabetes mellitus (T2DM). Although the association between diabetes mellitus and cancer risk was found about 100 years ago, the issue is not still clear. Many studies especially cohort and case–control studies have suggested a higher risk of cancer in patients with diabetes mainly in those with type 2 diabetes. Insulin concentration is high in these patients, and due to its mitogenic effects, it may be a possible hypotheses for higher risk of cancer in diabetic patients. Therefore, antidiabetic drugs, which are involved in insulin secretion and sensitivity, may have beneficial effects in cancer treatment. Several groups of drugs with different mechanisms of action, mostly prescribed orally, are used for the treatment of type 2 diabetes mellitus including, insulin sensitizers (thiazolidinediones), insulin secretagogues (sulfonylureas), and biguanides. In this review, the possible effects of antidiabetic drugs (biguanides, thiazolidinediones, and sulfonylureas) and some of their mechanisms for overcoming cancer will be discussed.     

Comparative Antidiabetic,Hypolipidemic, and Antioxidant Properties of Phyllanthus niruri. in Normal and Diabetic Rats

Abstract

The antidiabetic, hypolipidemic, and antioxidant properties of Phyllanthus niruri. (L) (Euphorbiaceae) were compared in normal, insulin-dependent diabetes mellitus (IDDM), and non–insulin-dependent diabetes mellitus (NIDDM) animals through evaluating the effects on carbohydrate and lipid metabolism and antioxidant activities. The alcohol extract of Phyllanthus niruri. produced significant antidiabetic effect in IDDM alone but lowered lipid profiles and improved body antioxidant activities in both IDDM and NIDDM animals. This investigation revealed that the lipid-lowering effect of Phyllanthus niruri. is independent from its antidiabetic action.     

An overview of pathophysiology and treatment of insulin resistance

Insulin resistance has emerged out as a concept linking diabetes mellitus and hypertension. Clinically it is characterized by hyperinsulinemia, hypertension, central obesity, abnormal lipid profile and cardiovascular complications. Insulin resistance is often associated with presence of anti-insulin antibodies and absent or dysfunctional insulin receptors. At molecular level insulin resistance appears to occur at the level of G-protein, kinase activation, glucose carriers (GLUT) and gene expression. Although with advent or research, the molecular mechanisms of insulin resistance are becoming more clear and there is development of new therapeutic agents like insulin sensitizers (thizolidinediones), in clinical practice, as of today, a patient with insulin resistance is looked upon as hypertensive or having diabetes mellitus. Accordingly he is taking either antihypertensives or antidiabetic drugs or both. It is thus essential to look into effects of these agents on insulin sensitivity. In recent years some scattered studies have been conducted to evaluate the effect of various antihypertensives and antidiabetics on insulin sensitivity. An antihypertensive or antidiabetic drug should directly benefit the cardiovascular risk profile of these patients. Although various newer approaches are explored to have a therapeutic benefit in insulin resistance, it is still a long way in the research, when a suitable pharmacological agent with least untoward effects will be available for the treatment of insulin residence.     

胰岛素治疗糖尿病合并肺结核的临床观察

目的观察胰岛素治疗糖尿病合并肺结核的疗效。方法选择我院糖尿病合并肺结核患者35例,根据患者的依从性随机分成2组,胰岛素组19例,口服降糖药组16例。2组降糖药不同,抗结核药相同,初治病例应用3HRZE/6-9HRE方案,复治病例应用3HRZE/9-12HRE方案,同时2组均给予左氧氟沙星静脉滴注1个月,观察1个月、3个月的疗效。结果胰岛素组的临床症状改善、胸片转归及血糖水平明显优于口服药组。结论糖尿病合并肺结核患者最佳降糖方案为胰岛素强化治疗,而肺结核化疗疗效与糖尿病控制情况密切相关。     

Pharmacogenomics of oral antidiabetic medications: current data and pharmacoepigenomic perspective

Type 2 diabetes mellitus (T2DM) is an increasingly prevalent disease. Several classes of drugs are currently available to treat T2DM patients; however, clinical response to these drugs often exhibits significant variation among individuals. For the oral antidiabetic drug classes of sulfonylureas, nonsulfonylurea insulin secretagogs, biguanides and thiazolidinediones, pharmacogenomic evidence has accumulated demonstrating an association between specific gene polymorphisms and interindividual variability in their therapeutic and adverse reaction effects. These polymorphisms are in genes of molecules involved in metabolism, transport and therapeutic mechanisms of the aforementioned drugs. Overall, it appears that pharmacogenomics has the potential to improve the management of T2DM and help clinicians in the effective prescribing of oral antidiabetic medications. Although pharmacogenomics can explain some of the heterogeneity in dose requirements, response and incidence of adverse effects of drugs between individuals, it is now clearly understood that much of the diversity in drug effects cannot be solely explained by studying the genomic diversity. Epigenomics, the field that focuses on nongenomic modifications that influence gene expression, may expand the scope of pharmacogenomics towards optimization of drug therapy. Therefore, pharmacoepigenomics, the combined analysis of genetic variations and epigenetic modifications, holds promise for the realization of personalized medicine. Although pharmacoepigenomics has so far been evaluated mainly in cancer pharmacotherapy, studies on epigenomic modifications during T2DM development provide useful data on the potential of pharmacoepigenomics to elucidate the mechanisms underlying interindividual response to oral antidiabetic treatment. In summary, the present article focuses on available data from pharmacogenomic studies of oral antidiabetic drugs and also provides an overview of T2DM epigenomic research, which has the potential to boost the development of pharmacoepigenomics in antidiabetic treatment.     

二肽基肽酶-4抑制剂进展与临床应用评价

目的：二肽基肽酶-4抑制剂的问世为抗糖尿病药宝库中增添了一朵奇葩,其进展神速,作用途径独特,迂回在胰岛β细胞和胰岛素之外,本文综述其作用特点和临床评价;方法：通过对国内外近期文献进行分析与评价。结果及结论：二肽基肽酶-4抑制剂作用确切,在大量的临床研究中显示了良好效果和安全性,为糖尿病患者展现了宽阔的治疗前景。     

罗格列酮治疗2型糖尿病的研究进展

噻唑烷二酮类药物为治疗2型糖尿病开辟了新途径，本文综述了罗格列酮治疗2型糖尿病的研究进展，分别就其作用机制、药理作用、药动学特性、药物相互作用和不良反应作一概述，为临床用药提供参考。     

胰岛素治疗糖尿病合并肺结核的临床观察

目的观察胰岛素治疗糖尿病合并肺结核的疗效。方法选择我院糖尿病合并肺结核患者35例,根据患者的依从性随机分成2组,胰岛素组19例,口服降糖药组16例。2组降糖药不同,抗结核药相同,初治病例应用3HRZE/6-9HRE方案,复治病例应用3HRZE/9-12HRE方案,同时2组均给予左氧氟沙星静脉滴注1个月,观察1个月、3个月的疗效。结果胰岛素组的临床症状改善、胸片转归及血糖水平明显优于口服药组。结论糖尿病合并肺结核患者最佳降糖方案为胰岛素强化治疗,而肺结核化疗疗效与糖尿病控制情况密切相关。     

Mechanisms and clinical effects of thiazolidinediones

Studies of pioglitazone, troglitazone, BRL 49653 and other thiazolidinediones in preclinical animal models of non-insulin dependent diabetes mellitus (NIDDM) and obesity led to the observation that these compounds were effective in reducing hyperglycaemia and hyperlipidaemia. In these models, animals treated with thiazolidinediones had notable improvements in blood glucose levels, hepatic glucose output, peripheral insulin resistance, and serum lipid levels. Mechanistic studies indicate that thiazolidinediones act at many intracellular sites and can influence several processes to increase cell sensitivity to insulin. These include influence on insulin receptor kinase activity, control of insulin receptor phosphorylation, change in number of insulin receptors, quantity and activity of GLUT-4, modulation of tumour necrosis factor (TNF) activity, activation of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and alteration of hepatic glucose metabolism. Available data on pioglitazone and troglitazone from clinical studies support the efficacy and safety of this class of compounds in reducing hyperglycaemia, hypertriglyceridaemia and insulin resistance associated with NIDDM. Currently, only troglitazone is approved for use in the United States and only in combination with insulin. This new pharmacological class of drugs has great promise for the treatment of NIDDM and also as a valuable research tool to further the understanding of the mechanisms that underlie NIDDM and insulin resistance syndrome.     

Mechanisms and clinical effects of thiazolidinediones

Studies of pioglitazone, troglitazone, BRL 49653 and other thiazolidinediones in preclinical animal models of non-insulin dependent diabetes mellitus (NIDDM) and obesity led to the observation that these compounds were effective in reducing hyperglycaemia and hyperlipidaemia. In these models, animals treated with thiazolidinediones had notable improvements in blood glucose levels, hepatic glucose output, peripheral insulin resistance, and serum lipid levels. Mechanistic studies indicate that thiazolidinediones act at many intracellular sites and can influence several processes to increase cell sensitivity to insulin. These include influence on insulin receptor kinase activity, control of insulin receptor phosphorylation, change in number of insulin receptors, quantity and activity of GLUT-4, modulation of tumour necrosis factor (TNF) activity, activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and alteration of hepatic glucose metabolism. Available data on pioglitazone and troglitazone from clinical studies support the efficacy and safety of this class of compounds in reducing hyperglycaemia, hypertriglyceridaemia and insulin resistance associated with NIDDM. Currently, only troglitazone is approved for use in the United States and only in combination with insulin. This new pharmacological class of drugs has great promise for the treatment of NIDDM and also as a valuable research tool to further the understanding of the mechanisms that underlie NIDDM and insulin resistance syndrome.     

Effects of the combination of SGLT2 selective inhibitor ipragliflozin and various antidiabetic drugs in type 2 diabetic mice

The sodium-glucose cotransporter 2 (SGLT2) is responsible for most glucose reabsorption in the kidney and has been proposed as a novel therapeutic target for the treatment of type 2 diabetes. In the present study, the combinatory effects of SGLT2 selective inhibitor ipragliflozin and various antidiabetic drugs in high-fat diet and streptozotocin-nicotinamide-induced type 2 diabetic mice were investigated. Ipragliflozin dose-dependently increased urinary glucose excretion and improved glucose tolerance. In addition, each antidiabetic drug (mitiglinide, glibenclamide, sitagliptin, insulin, metformin, voglibose, or rosiglitazone) also significantly improved glucose tolerance without affecting urinary glucose excretion. Combination treatment of ipragliflozin with each antidiabetic drug additively improved glucose tolerance. In these experiments, ipragliflozin-induced increases in urinary glucose excretion were not influenced by combination treatment with antidiabetic drugs. Further, ipragliflozin did not affect antidiabetic drug-induced insulinotropic action (mitiglinide and glibenclamide), increases in plasma glucagon-like peptide-1 and insulin levels via inhibition of dipeptidyl peptidase 4 activity (sitagliptin), increases in plasma insulin level (insulin), decreases in hepatic phosphoenolpyruvate carboxykinase activity (metformin), inhibition of small intestinal disaccharidase activity (voglibose), or improvement of impaired insulin secretion (rosiglitazone). These results suggest that combination treatment of ipragliflozin with various antidiabetic drugs additively enhances the improvement in glucose tolerance without affecting each drug’s unique pharmacological effects. Ipragliflozin may therefore be expected to be effective when administered as part of a combination regimen in the treatment of type 2 diabetes.     

Berberine in type 2 diabetes therapy: a new perspective for an old antidiarrheal drug?

Type 2 diabetes mellitus (T2DM) and dysglycemia (impaired glucose tolerance and/or impaired fasting glucose) are increasingly contributing to the global burden of disease. Despite the continued introduction of hypoglycemic drugs, intervention in diabetes and its related complications remains a major global medical problem. Traditional Chinese medicine offers a number of potential candidates for developing hypoglycemic drugs. Berberine (BER), an isoquinoline alkaloid extract, has been commonly used as an oral drug to treat gastroenteritis and diarrhea for more than 1400 years. Although the antidiabetic effect of berberine has been noted in diabetic patients and demonstrated diabetic animal models in the last decade, its use is not yet accepted in the general medical community, for two reasons: its mechanism of action remains to be determined, and its bioavailability is low. Therefore, characterization of its mechanism of action and enhancement of its bioavailability are most important and the subject of current investigations. Recent studies have also revealed beneficial effects of berberine on diabetic complications. In this review the antidiabetic mechanism of action of berberine, its effect on diabetic complications, and efforts to improve its bioavailability are summarized. These studies may lead to its wider use for the treatment of type 2 diabetes mellitus and its complications.     

Therapeutic traditions in type 2 diabetes — are they changing?

The utilisation of antidiabetic drugs reflects both the prevalence of diabetes and the different therapeutic traditions of physicians. A questionnaire survey to study attitudes to the use of oral antidiabetic drugs amongst physicians and possible changes in treatment habits was carried out in a representative sample of Finnish physicians (n=454) in 1992 and the results were compared with those of a similar survey carried out in 1985, and with drug utilisation statistics.The mean fasting blood glucose level at which a physician would start pharmacological treatment was 8.7 mmol·l^–1, which was significantly lower than in the 1985 survey. The responses to various case histories suggested a more active approach to pharmacological treatment compared to the 1985 survey. Insulin treatment especially seems to have gained in popularity. This change in attitude was paralled by an increase in the consumption of antidiabetic drugs in Finland during the observation period. The increase in use of oral drugs was steeper in Finland than in Norway and Sweden.Whether this active approach will improve the metabolic control and prognosis of patients with Type 2 diabetes, remains to be demonstrated.     

Troglitazone: a review of its use in the management of type 2 diabetes mellitus

Troglitazone is the first of a new group of oral antidiabetic drugs, the thiazolidinediones, and is indicated for the treatment of patients with type 2 (non-insulin-dependent) diabetes mellitus. Troglitazone acts by enhancing the effects of insulin at peripheral target sites and, unlike the sulphonylurea drugs, is not associated with hypoglycaemia when administered as monotherapy. Clinical trials with troglitazone (usually 200 to 600 mg/day) in patients with type 2 diabetes mellitus consistently showed marked improvement in glycaemic control, as well as reductions in fasting serum insulin, C-peptide and triglyceride levels. Comparative studies with either glibenclamide (glyburide) or metformin indicated similar glycaemic control with troglitazone or these agents. Serum insulin levels were lower with troglitazone than with glibenclamide. Clinical trials of up to approximately 2 years' duration showed that glycaemic control is maintained with troglitazone on a long term basis. In general, troglitazone is well tolerated by the majority of patients. However, discontinuation of troglitazone because of elevated liver enzyme levels occurs in approximately 2% of patients receiving the drug, and frequent monitoring of liver enzymes is required (e.g. at least 11 times during the first year of therapy). Among patients who started troglitazone therapy in 1998 (after the incorporation of a boxed warning and increased monitoring requirements in the product labelling), the estimated risk of liver-related death is approximately 1 in 100,000. CONCLUSIONS: Troglitazone improves the ability of target cells to respond to insulin. The drug has been shown to improve glycaemic control in patients with type 2 diabetes mellitus when used as monotherapy or in combination with other oral antidiabetic drugs or insulin, and its efficacy is similar to that of glibenclamide or metformin. Although troglitazone is generally well tolerated, close monitoring of liver enzyme function is required to minimise the rare occurrence of serious hepatic dysfunction. Drug acquisition and liver function monitoring costs, as well as potential adverse effects, are important factors that may ultimately determine the precise place of troglitazone in the management of type 2 diabetes mellitus. Nevertheless, as the first member of a new class of oral antidiabetic agents, the thiazolidinediones, troglitazone offers an effective treatment option in patients with type 2 diabetes mellitus through its action of improving insulin sensitivity.     

Section Review—Oncologic,Endocrine & Metabolic: Potential Use of Vanadium Compounds in the Treatment of Diabetes Mellitus

Vanadium is a trace element of ubiquitous occurrence. Vanadium compounds have been shown to exert a variety of insulin-like effects both in vitro and in vivo. These effects include their ability to lower hyperglycaemia in animal models of type I, insulin-dependent diabetes mellitus (IDDM), and type II, non-insulin-dependent diabetes mellitus (NIDDM). Vanadium therapy also corrects several metabolic abnormalities associated with the diabetic state. Preliminary studies in human diabetic subjects have shown an improved insulin sensitivity in NIDDM and in some IDDM subjects. Thus, vanadium compounds, either alone or in combination with other agents, have the potential to serve as antidiabetic agents.     

Meglitinide analogues in the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus is a complex heterogenous metabolic disorder in which peripheral insulin resistance and impaired insulin release are the main pathogenetic factors. The rapid response of the pancreatic beta-cells to glucose is already markedly disturbed in the early stages of type 2 diabetes mellitus. The consequence is often postprandial hyperglycaemia, which seems to be extremely important in the development of secondary complications, especially macrovascular disease. Therefore one of the main aims of treatment is to minimise blood glucose oscillations and attain near-normal glycosylated haemoglobin levels. Meglitinide analogues belong to a new family of insulin secretagogues which stimulate insulin release by inhibiting ATP-sensitive potassium channels of the beta-cell membrane via binding to a receptor distinct from that of sulphonylureas (SUR1/KIR 6.2). The pharmacokinetic and pharmacodynamic properties of repaglinide, the first drug of these new antihyperglycaemic agents on the market, and of nateglinide, which will be available soon, differ markedly from the currently used sulphonylureas [mainly glibenclamide (glyburide) and glimepiride]. Repaglinide and nateglinide are absorbed rapidly, stimulate insulin release within a few minutes, are rapidly metabolised in the liver and are mainly excreted in the bile. Therefore, following preprandial administration of these drugs, insulin is more readily available during and just after the meal. This leads to a significant reduction in postprandial hyperglycaemia without the danger of hypoglycaemia between meals. The short action of these compounds and biliary elimination makes repaglinide and nateglinide especially suitable for patients with type 2 diabetes mellitus who would like to have a more flexible lifestyle, need more flexibility because of unplanned eating behaviour (e.g. geriatric patients) or in whom one of the other first-line antidiabetic drugs, i.e. metformin, is strictly contraindicated (e.g. nephropathy with creatinine clearance < or = 50 ml/min). Meglitinide analogues act synergistically with metformin and thiazolidinediones (pioglitazone and rosiglitazone) and can be also combined with long-acting insulin (NPH insulin at bedtime). Therefore, these drugs enrich the palette of antidiabetic drugs and make the treatment more flexible and better tolerated, which both add to better metabolic control and support the empowerment and compliance of the patient. However, this will only be the case if the patient and the diabetes care team are trained for this new therapeutic schedule and the healthcare system is able to pay for these rather expensive drugs.     

Latest research and development trends in non-insulin anti-diabetics

Type 2 diabetes mellitus, also called non-insulin dependent diabetes mellitus, is a chronic endocrine disease characterized by insulin resistance in tissues such as fat, liver and skeletal muscle, and impaired insulin secretion in pancreatic β cells. The prevalence and incidence of type 2 diabetes exploded over last decades along with increased population obesity owing to western lifestyle factors such as lack of exercise and high calorie diets. As diabetes progresses without appropriate treatment, many micro- and macro-vascular complications occur, leading to increased risk of mortality. Although lifestyle modifications including a healthier diet and more frequent exercise are suggested as initial therapy for type 2 diabetes, pharmacotherapy is required in many cases. Currently, several anti-diabetic drugs with different mechanisms of action are available, but increased effectiveness and tolerability are a still unmet need for diabetes pharmacotherapy. Thus, the development of new anti-diabetic drugs is an active research area in both academia and the pharmaceutical industry. This review focuses on the targets in the latest developments of non-insulin anti-diabetics that attract the most interest in this disease area.