Current management strategies for coexisting diabetes mellitus and obesity

Mapping Obesity Trends in Saudi Arabia: A Four-Year Description Study

OBJECTIVE

Our study aims to map the trends in obesity prevalence over the past four years and to describe the health, behavior, and psychological factors of people living with obesity in Saudi.

METHOD

This is a secondary data analysis using the Sharik Health Indicators Surveillance System (SHISS) from 2020 to 2023. The SHISS dataset comprises cross-sectional telephone interviews carried out quarterly across all administrative regions of Saudi Arabia. Recruitment of participants was restricted to Saudi resident adults only.

RESULTS

The study analyzed data from 92,137 participants, with a balanced region and gender distribution. The average age of participants was 36.83 ± 13.68 years. The prevalence of obesity showed minor fluctuations over four years, with the highest at 22.2% in 2020 and lowest at 21.4% in 2023. This study showed that a slight decline in daily smoking rates was observed from 2020 to 2023 across all categories. Participants living with obesity reported a higher consumption of fruits and vegetables compared to their not with obesity counterparts. In addition, participants living with obesity engaged less frequently in physical activities compared to those without obesity. Moreover, people living with obesity have higher incidence rates of depression and anxiety, as well as various of chronic diseases.

CONCLUSIONS

This study highlights the complex factors affecting obesity prevalence in Saudi Arabia. Despite progress, ongoing health promotion and disease prevention are crucial to address the persistent challenges driven by behavioral and socio-economic factors. Continued surveillance and longitudinal studies are essential to track trends in obesity, smoking, and physical activity, ensuring that health initiatives align with population needs.

Sex differences in oxidative stress level and antioxidative enzymes expression and activity in obese pre-diabetic elderly rats treated with metformin or liraglutide

Aim

To determine the effects of metformin or liraglutide on oxidative stress level and antioxidative enzymes gene transcription and activity in the blood and vessels of pre-diabetic obese elderly Sprague-Dawley (SD) rats of both sexes.

Methods

Male and female SD rats were assigned to the following groups: a) control group (fed with standard rodent chow); b) high-fat and high-carbohydrate diet (HSHFD) group fed with HSHFD from 20-65 weeks of age; c) HSHFD+metformin treatment (50 mg/kg/d s.c.); and d) HSHFD+liraglutide treatment (0.3 mg/kg/d s.c). Oxidative stress parameters (ferric reducing ability of plasma and thiobarbituric acid reactive substances) and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity and gene transcription were determined from serum, aortas, and surface brain blood vessels (BBV).

Results

HSHFD increased body weight in both sexes compared with the control group, while liraglutide prevented this increase. Blood glucose level did not change. The liraglutide group had a significantly increased antioxidative capacity compared with the HSHFD group in both sexes. The changes in antioxidative enzymes’ activities in plasma were more pronounced in male groups. The changes in gene expression of antioxidative enzymes were more prominent in microvessels and may be attributed to weight gain prevention.

Conclusions

Obesity and antidiabetic drugs caused sex-related differences in the level of antioxidative parameters. Liraglutide exhibited stronger antioxidative effects than metformin. These results indicate that weight gain due to HSHFD is crucial for developing oxidative stress and for inhibiting antioxidative protective mechanisms.

ZnO nanoparticles and their acarbose-capped nanohybrids as inhibitors for human salivary amylase

The authors report a controlled synthesis of biocompatible ZnO and acarbose-capped nanohybrids, and examined the inhibition activities of these nanosystems with human salivary α-amylase (HSA) activity. XRD measurements reveal ZnO present in wurtzite phase with hexagonal structure. The average size of ZnO particles for the two studied nanosystems was estimated to lie between 10 to 12 nm using Scherrer equation. These particles depict the onset of absorption at about 320 nm and the band-gap emission at about 370 nm, which are fairly blue shifted as compared with the bulk ZnO and have been understood due to the size quantisation effect. The inhibitory action of thioglycerol capped ZnO nanoparticles (SP1) and acarbose drug (used for diabetes type II) capped ZnO (SP2) for HSA was observed to 61 and72%, respectively. The inhibition activity of the SP1 alone was found to be very similar to that of acarbose and the coating of these particles with drug (SP2) demonstrated an enhancement in inhibition activity of the enzyme by about 30%. From the inhibition studies, it is confirmed that these nanosystems showed better inhibition activity at physiological temperature and pH. These nanosystems are projected to have potential applications in diabetes type II control.

Associations of A-FABP with Anthropometric and Metabolic Indices and Inflammatory Cytokines in Obese Patients with Newly Diagnosed Type 2 Diabetes

The study aimed to evaluate the relationship between anthropometric and metabolic indices, inflammatory cytokines, and adipocyte fatty acid-binding protein (A-FABP) in obese patients with newly diagnosed type 2 diabetes. The study included 48 nonobese subjects with newly diagnosed type 2 diabetes, 42 obese subjects with newly diagnosed type 2 diabetes, 30 simple obese subjects, and 30 matched normal subjects. Serum A-FABP was assessed by enzyme-linked immunosorbent assay. Pearson's correlations and multiple linear regression stepwise analysis were used to analyze correlations of A-FABP with anthropometric and metabolic indices and inflammatory cytokines. Obese subjects with newly diagnosed type 2 diabetes had elevated A-FABP compared to normal control, nondiabetic obese patients, and nonobese diabetic patients. A-FABP was significantly correlated with glycated hemoglobin A1C (HbA1C), BMI, triglyceride, Homeostasis Model Assessment Index (HOMA-IR), waist hip rate, C-reactive protein, IL-6, and HDL-C in obese subjects with type 2 diabetes. In multiple linear regression stepwise analysis, BMI, HbA1C, and HOMA-IR were significantly independent determinants for A-FABP. BMI, HbA1C, and HOMA-IR are independently associated with A-FABP in obese subjects with newly diagnosed type 2 diabetes. A-FABP may be related to insulin resistance and inflammation in type 2 diabetes and concomitant obesity.

Background and Treatment of Metabolic Syndrome: A Therapeutic Challenge

Metabolic syndrome is characterized by a clustering of cardiovascular and metabolic risk factors. This syndrome is now widely recognized as a distinct pathologic entity. It is receiving a great deal of attention in the medical literature and also in the lay press. People with metabolic syndrome have a clustering of the following risk factors, including detrimental changes in glucose tolerance and insulin resistance, abdominal (visceral) obesity, atherogenic dyslipidemia, and hypertension. Metabolic syndrome is associated with important cardiovascular and cerebrovascular and metabolic risks. Prevention and treatment are therefore of great importance. Preventive measures involving lifestyle are mandatory. In addition, metabolic syndrome patients will require pharmacologic treatment, usually for the rest of their lives. Complex patterns of drug treatment are required. This review provides an extensive and critical review of the drug treatment of this complex pathologic entity.

The efficacy and safety of teneligliptin added to ongoing metformin monotherapy in patients with type 2 diabetes: a randomized study with open label extension

OBJECTIVE

The study investigated the efficacy and tolerability of teneligliptin co-administered to patients with type 2 diabetes mellitus (T2DM) who were inadequately controlled by stable metformin monotherapy ≥ 1000 mg/day.

METHODS

A total of 447 patients from 55 European centers who completed a 14-day screening and 14-day run-in phase, received randomized double-blind treatment with 5, 10, 20 or 40 mg teneligliptin or placebo once daily, for 24 weeks. 364 patients continued treatment in a 28-week open label extension during which they received teneligliptin 20 mg once daily.

RESULTS

Co-administration of teneligliptin (5 to 40 mg) with metformin demonstrated dose-related and statistically significant reductions in HbA1c after 24 weeks (-0.30 to -0.63% placebo adjusted) of double-blind treatment. The greatest reduction in HbA1c was seen with teneligliptin at 40 mg (-0.63%) at Week 24. There was also a dose-dependent increase in proportion of responders achieving HbA1c < 7.0% at this endpoint. Responses were maintained throughout 28 weeks open label treatment with 20 mg teneligliptin. Treatment was well tolerated to Week 52 and the overall incidence of hypoglycemia during 52 weeks was 2.3%.

CONCLUSIONS

Teneligliptin co-administered with metformin produced significant reductions in HbA1c in patients with T2DM without increasing the risk of hypoglycemia.

Combating the dual burden: therapeutic targeting of common pathways in obesity and type 2 diabetes

The increasing prevalence of obesity is contributing substantially to the ongoing epidemic of type 2 diabetes. Abdominal adiposity, a feature of ectopic fat syndrome, is associated with silent inflammation, abnormal hormone secretion, and various metabolic disturbances that contribute to insulin resistance and insulin secretory defects, resulting in type 2 diabetes, and induce a toxic pattern that leads to cardiovascular disease, liver pathologies, and cancer. Despite the importance of weight control strategies in the prevention and management of type 2 diabetes, long-term results from lifestyle or drug interventions are generally disappointing. Furthermore, most of the classic glucose-lowering drugs have a side-effect of weight gain, which renders the management of most overweight or obese people with type 2 diabetes even more challenging. Many anti-obesity pharmacological drugs targeting central control of appetite were withdrawn from the market because of safety concerns. The gastrointestinal lipase inhibitor orlistat was the only anti-obesity drug available until the recent US, but not European, launch of phentermine-controlled-release topiramate and lorcaserin. Improved knowledge about bodyweight regulation opens new prospects for the potential use of peptides derived from the gut or the adipose tissue. Combination therapy will probably be necessary to avoid compensatory mechanisms and potentiate initial weight loss while avoiding weight regain. New glucose-lowering treatments, especially glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter-2 inhibitors, offer advantages over traditional antidiabetic drugs by promoting weight loss while improving glucose control. In this Review, we explore the overlapping pathophysiology and also how various treatments can, alone or in combination, combat the dual burden of obesity and type 2 diabetes.

Cardiovascular effects of dipeptidyl peptidase-4 inhibitors: from risk factors to clinical outcomes

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are oral incretin-based glucose-lowering agents with proven efficacy and safety in the management of type 2 diabetes mellitus (T2DM). In addition, preclinical data and mechanistic studies suggest a possible additional non-glycemic beneficial action on blood vessels and the heart, via both glucagon-like peptide-1-dependent and glucagon-like peptide-1-independent effects. As a matter of fact, DPP-4 inhibitors improve several cardiovascular risk factors: they improve glucose control (mainly by reducing the risk of postprandial hyperglycemia) and are weight neutral; may lower blood pressure somewhat; improve postprandial (and even fasting) lipemia; reduce inflammatory markers; diminish oxidative stress; improve endothelial function; and reduce platelet aggregation in patients with T2DM. In addition, positive effects on the myocardium have been described in patients with ischemic heart disease. Results of post hoc analyses of phase 2/3 controlled trials suggest a possible cardioprotective effect with a trend (sometimes significant) toward lower incidence of major cardiovascular events with sitagliptin, vildagliptin, saxagliptin, linagliptin, or alogliptin compared with placebo or other active glucose-lowering agents. However, the definite relationship between DPP-4 inhibition and better cardiovascular outcomes remains to be proven. Major prospective clinical trials involving various DPP-4 inhibitors with predefined cardiovascular outcomes are under way in patients with T2DM and a high-risk cardiovascular profile: the Sitagliptin Cardiovascular Outcome Study (TECOS) on sitagliptin, the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction (SAVOR-TIMI) 53 trial on saxagliptin, the Cardiovascular Outcomes Study of Alogliptin in Subjects With Type 2 Diabetes and Acute Coronary Syndrome (EXAMINE) trial on alogliptin, and the Cardiovascular Outcome Study of Linagliptin Versus Glimepiride in Patients With Type 2 Diabetes (CAROLINA) on linagliptin. If these trials confirm that a DPP-4 inhibitor can reduce the cardiovascular burden of T2DM, it would be major progress that would dramatically influence the management of the disease.

Cardiovascular effects of gliptins

Dipeptidyl peptidase 4 (DPP-4) inhibitors (commonly referred to as gliptins) are a novel class of oral antihyperglycaemic agents with demonstrated efficacy in the treatment of type 2 diabetes mellitus (T2DM). Preclinical data and mechanistic studies have indicated a possible beneficial action on blood vessels and the heart, via both glucagon-like peptide 1 (GLP-1)-dependent and GLP-1-independent effects. DPP-4 inhibition increases the concentration of many peptides with potential vasoactive and cardioprotective effects. Clinically, DPP-4 inhibitors improve several risk factors in patients with T2DM. They improve blood glucose control (mainly by reducing postprandial glycaemia), are weight neutral (or even induce modest weight loss), lower blood pressure, improve postprandial lipaemia, reduce inflammatory markers, diminish oxidative stress, and improve endothelial function. Some positive effects on the heart have also been described in patients with ischaemic heart disease or congestive heart failure, although their clinical relevance requires further investigation. Post-hoc analyses of phase II-III, controlled trials suggest a possible cardioprotective effect with a trend for a lower incidence of major cardiovascular events with gliptins than with placebo or active agents. However, the actual relationship between DPP-4 inhibition and cardiovascular outcomes remains to be proven. Major prospective clinical trials with predefined cardiovascular outcomes and involving various DPP-4 inhibitors are now underway in patients with T2DM and a high-risk cardiovascular profile.

Pharmacokinetics and metabolism of [14C]anagliptin, a novel dipeptidyl peptidase-4 inhibitor, in humans

1. The disposition of anagliptin, an orally active, highly selective dipeptidyl peptidase-4 inhibitor, was investigated after a single oral dose of 100 mg/1.92 MBq [(14)C]anagliptin to six healthy men. Almost all the dose (98.2%) was recovered within 168 h: 73.2% in urine and 25.0% in faeces. 2. Anagliptin was rapidly absorbed, with peak plasma concentrations of unchanged drug attained at a mean time of 1.8-h postdose. Mean fraction of the dose absorbed was >73%. Unchanged drug and a carboxylate metabolite (M1) were the major components in plasma, accounting for 66.0 and 23.4% of total plasma radioactivity area under the curve, respectively. 3. Anagliptin was incompletely metabolized, with about 50% dose eliminated as unchanged drug (46.6% in urine and 4.1% in faeces). Metabolism to M1 accounted for 29.2% of the dose. No other metabolite accounted for >1% dose in excreta or yielded measurable systemic exposure. Terminal half-life of anagliptin and M1 was 4.37 and 9.88 h, respectively. Renal clearance of unbound anagliptin and unbound M1 far exceeded glomerular filtration rate, indicating active renal elimination: that might reflect the fact that anagliptin may be a substrate of OAT1, OAT3, MDR1 and MRP2, and M1 a substrate of OAT3, BCRP, MRP2 and MRP4.

A study of the use of drugs in the treatment of obesity among adult females

Purpose

Obesity is a prevalent health problem among adult females in Egypt. The aim of this study is to investigate the use of drugs in managing of obesity among adult females.

Design/methodology/approach

A random sample of 764 obese adult females with a BMI >25 were included in the study. Data were collected using a pre‐coded questionnaire on personal characteristics, type of regimen followed, the use of anti‐obesity drugs, sources of information about medicine, compliance pattern and the outcome of using medicine.

Findings

The results show that 19.9 per cent of the females took medicines while dieting and another 11.4 per cent while dieting and exercising. Physicians were the main source of advice about anti‐obesity medicine (33.1 per cent), followed by pharmacists (25.5 per cent), peers (24.2 per cent) and mass media (17.2 per cent). Medicines stimulating the metabolism were most commonly used (42.7 per cent), followed by drugs blocking fat absorption (24.3 per cent), appetite depressants (23.3 per cent) and herbs (18.4 per cent). The most common side effects were diarrhoea (30.1 per cent) followed by headache (20.1 per cent) and depression (17.2 per cent). The data show that 47.7 per cent of the females fully complied while 30.5 per cent did not comply. The intake of medicine while dieting induced weight loss among 48.9 per cent of the subjects, 18.0 per cent did not report weight loss and 33.1 per cent stopped medicine intake. Older females and those with a BMI >35 were more keen to seek advice from a physician, were more likely to comply fully and reported the highest rate of weight loss. The use of anti‐obesity drugs was highest (44 per cent) among university graduates compared to 24.8 per cent among females with limited education.

Originality/value

This study presents the first report of the pattern of using anti‐obesity drugs in Egypt.

Childhood obesity: a life-long health risk

Childhood obesity has become major health concern for physicians, parents, and health agencies around the world. Childhood obesity is associated with an increased risk for other diseases not only during youth but also later in life, including diabetes, arterial hypertension, coronary artery disease, and fatty liver disease. Importantly, obesity accelerates atherosclerosis progression already in children and young adults. With regard to pathophysiological changes in the vasculature, the striking similarities between physiological changes related to aging and obesity-related abnormalities are compatible with the concept that obesity causes "premature" vascular aging. This article reviews factors underlying the accelerated vascular disease development due to obesity. It also highlights the importance of recognizing childhood obesity as a disease condition and its permissive role in aggravating the development of other diseases. The importance of childhood obesity for disease susceptibility later in life, and the need for prevention and treatment are also discussed.

A review of gliptins in 2011

INTRODUCTION

Dipeptidylpeptidase-4 (DPP-4) inhibitors offer new options for the management of type 2 diabetes (T2DM).

AREAS COVERED

This paper is an updated review, providing an analysis of both the similarities and the differences between the various compounds known as gliptins, currently used in the clinic (sitagliptin, vildagliptin, saxagliptin, alogliptin and linagliptin). This paper discusses the pharmacokinetic and pharmacodynamic characteristics of gliptins; both the efficacy and safety profiles of gliptins in clinical trials (compared with classical glucose-lowering agents), given as monotherapy or in combination, including in special populations; the positioning of DPP-4 inhibitors in the management of T2DM in recent guidelines; and various unanswered questions and perspectives.

EXPERT OPINION

The role of DPP-4 inhibitors in the therapeutic armamentarium of T2DM is evolving, as their potential strengths and weaknesses become better defined. Future critical issues may include the durability of glucose control, resulting from better β-cell protection, positive effects on cardiovascular outcomes and long-term safety issues.

Childhood obesity: a life-long health risk

Childhood obesity has become major health concern for physicians, parents, and health agencies around the world. Childhood obesity is associated with an increased risk for other diseases not only during youth but also later in life, including diabetes, arterial hypertension, coronary artery disease, and fatty liver disease. Importantly, obesity accelerates atherosclerosis progression already in children and young adults. With regard to pathophysiological changes in the vasculature, the striking similarities between physiological changes related to aging and obesity-related abnormalities are compatible with the concept that obesity causes "premature" vascular aging. This article reviews factors underlying the accelerated vascular disease development due to obesity. It also highlights the importance of recognizing childhood obesity as a disease condition and its permissive role in aggravating the development of other diseases. The importance of childhood obesity for disease susceptibility later in life, and the need for prevention and treatment are also discussed.

Investigation of effect on glycosylated hemoglobin, blood pressure, and body mass index of diabetes intensive education program in patients with type 2 diabetes mellitus

This study investigated the effects of a diabetes intensive education program (DIEP) on glycosylated hemoglobin (HbA(1)c), body mass index (BMI), and arterial blood pressure (BP). An 8-week randomized-controlled trial was conducted in Cumhuriyet University Hospital. Diabetes patients were randomized to control group (CG; n = 25) and intervention group (IG; n = 25) who received DIEP, including the factors affecting metabolic control and implementation of diabetes guidelines. Primary outcomes included HbA(1)c, BP, and BMI. After the 8 weeks, there was a significant decrease in HbA(1)c mean values for the intervention group. Also, BP significantly decreased from 143/87 to 130/80 mmHg in the IG as compared with an increase from 137/82 to 137/86 mmHg in the CG. In addition, the results demonstrated that DIEP improved the number of patients at goal for BP (130/80 mmHg). Baseline BMI did not change significantly in either group during the course of the study. These findings show that the DIEP may be effective in decreasing HbA(1)c levels and improving adherence to BP control.

Cardiovascular risk-benefit profile of sibutramine

Sibutramine is a combined norepinephrine and serotonin reuptake inhibitor used as an antiobesity agent to reduce appetite and promote weight loss in combination with diet and exercise. At a daily dose of 10-20 mg, it was initially considered to have a good safety profile, as it does not induce primary pulmonary hypertension or adverse effects on cardiac valves, in contrast to previous reports relating to some other antiobesity agents. However, it exerts disparate effects on cardiovascular risk factors. On the one hand, sibutramine may have antiatherogenic activities, as it improves insulin resistance, glucose metabolism, dyslipidemia, and inflammatory markers, with most of these effects resulting from weight loss rather than from an intrinsic effect of the drug. On the other hand, because of its specific mode of action, sibutramine exerts a peripheral sympathomimetic effect, which induces a moderate increase in heart rate and attenuates the reduction in BP attributable to weight loss or even slightly increases BP. It may also prolong the QT interval, an effect that could induce arrhythmias. Because of these complex effects, it is difficult to conclude what the final impact of sibutramine on cardiovascular outcomes might be. Sibutramine has been shown to exert favorable effects on some surrogate cardiovascular endpoints such as reduction of left ventricular hypertrophy and improvement of endothelial dysfunction. A good cardiovascular safety profile was demonstrated in numerous 1- to 2-year controlled trials, in both diabetic and nondiabetic well selected patients, as well as in several observational studies. However, since 2002, several cardiovascular adverse events (hypertension, tachycardia, arrhythmias, and myocardial infarction) have been reported in sibutramine-treated patients. This led to a contraindication of the use of this antiobesity agent in patients with established coronary heart disease, previous stroke, heart failure, or cardiac arrhythmias. SCOUT (Sibutramine Cardiovascular and Diabetes Outcome Study) was designed to prospectively evaluate the efficacy/safety ratio of sibutramine in a high-risk population. The efficacy/safety results of the first 6-week lead-in open period of treatment with sibutramine 10 mg/day were reassuring in 10 742 overweight/obese high-risk subjects (97% had cardiovascular disease, 88% had hypertension, and 84% had type 2 diabetes mellitus). However, the final results of SCOUT showed that long-term (5 years') treatment with sibutramine (10-15 mg/day) exposed subjects with pre-existing cardiovascular disease to a significantly increased risk for nonfatal myocardial infarction and nonfatal stroke, but not cardiovascular death or all-cause mortality. Because the benefit of sibutramine as a weight-loss aid seems not to outweigh the cardiovascular risks, the European Medicines Agency recommended the suspension of marketing authorizations for sibutramine across the EU. The US FDA stated that the drug should carry a 'black box' warning due to an increased risk of stroke and heart attack in patients with a history of cardiovascular disease. In conclusion, concern still persists about the safety profile of sibutramine regarding cardiovascular outcomes, and the drug should not be prescribed for overweight/obese patients with a high cardiovascular risk profile.

Pharmacokinetic and pharmacodynamic evaluation of sitagliptin plus metformin

IMPORTANCE OF THE FIELD

Type 2 diabetes is an increasingly prevalent disease resulting from various complex combinations of defects in insulin secretion and insulin action. Adequate blood glucose control is necessary to minimize complications. DPP IV inhibitors (sitagliptin, vildagliptin, saxagliptin) offer new options for combined pharmacological therapy.

AREAS COVERED IN THIS REVIEW

An extensive literature search was performed to analyze the potential pharmacokinetic (PK) and pharmacodynamic (PD) interactions between metformin (first-line drug for the management of type 2 diabetes) and sitagliptin (first commercialized DPP IV inhibitor). Metformin and sitagliptin may be administered together, either separately or in fixed-dose combination.

WHAT THE READER WILL GAIN

Updated information about PK/PD data on metformin alone, sitagliptin alone and sitagliptin plus metformin. Metformin and sitagliptin are not prone to PK drug-drug interactions. Their co-administration, either separately or in a fixed-dose combination, improves blood glucose control more potently than either compound separately, without hypoglycemia and without increasing metformin-related gastrointestinal side effects.

TAKE HOME MESSAGE

The combination sitagliptin plus metformin may be used as a first- or second-line therapy in the management of type 2 diabetes.

Dipeptidylpeptidase-4 inhibitors (gliptins): focus on drug-drug interactions

Patients with type 2 diabetes mellitus (T2DM) are generally treated with many pharmacological compounds and are exposed to a high risk of drug-drug interactions. Indeed, blood glucose control usually requires a combination of various glucose-lowering agents, and the recommended global approach to reduce overall cardiovascular risk generally implies administration of several protective compounds, including HMG-CoA reductase inhibitors (statins), antihypertensive compounds and antiplatelet agents. New compounds have been developed to improve glucose-induced beta-cell secretion and glucose control, without inducing hypoglycaemia or weight gain, in patients with T2DM. Dipeptidylpeptidase-4 (DPP-4) inhibitors are novel oral glucose-lowering agents, which may be used as monotherapy or in combination with other antidiabetic compounds, metformin, thiazolidinediones or even sulfonylureas. Sitagliptin, vildagliptin and saxagliptin are already on the market, either as single agents or in fixed-dose combined formulations with metformin. Other compounds, such as alogliptin and linagliptin, are in a late phase of development. This review summarizes the available data on drug-drug interactions reported in the literature for these five DDP-4 inhibitors: sitagliptin, vildagliptin, saxagliptin, alogliptin and linagliptin. Possible pharmacokinetic interferences have been investigated between each of these compounds and various pharmacological agents, which were selected because there are other glucose-lowering agents (metformin, glibenclamide [glyburide], pioglitazone/rosiglitazone) that may be prescribed in combination with DPP-4 inhibitors, other drugs that are currently used in patients with T2DM (statins, antihypertensive agents), compounds that are known to interfere with the cytochrome P450 (CYP) system (ketoconazole, diltiazem, rifampicin [rifampin]) or with P-glycoprotein transport (ciclosporin), or agents with a narrow therapeutic safety window (warfarin, digoxin). Generally speaking, almost no drug-drug interactions or only minor drug-drug interactions have been reported between DPP-4 inhibitors and any of these drugs. The gliptins do not significantly modify the pharmacokinetic profile and exposure of the other tested drugs, and the other drugs do not significantly alter the pharmacokinetic profile of the gliptins or exposure to these. The only exception concerns saxagliptin, which is metabolized to an active metabolite by CYP3A4/5. Therefore, exposure to saxagliptin and its primary metabolite may be significantly modified when saxagliptin is coadministered with specific strong inhibitors (ketoconazole, diltiazem) or inducers (rifampicin) of CYP3A4/5 isoforms. The absence of significant drug-drug interactions could be explained by the favourable pharmacokinetic characteristics of DPP-4 inhibitors, which are not inducers or inhibitors of CYP isoforms and are not bound to plasma proteins to a great extent. Therefore, according to these pharmacokinetic findings, which were generally obtained in healthy young male subjects, no dosage adjustment is recommended when gliptins are combined with other pharmacological agents in patients with T2DM, with the exception of a reduction in the daily dosage of saxagliptin when this drug is used in association with a strong inhibitor of CYP3A4/A5. It is worth noting, however, that a reduction in the dose of sulfonylureas is usually recommended when a DPP-4 inhibitor is added, because of a pharmacodynamic interaction (rather than a pharmacokinetic interaction) between the sulfonylurea and the DPP-4 inhibitor, which may result in a higher risk of hypoglycaemia. Otherwise, any gliptin may be combined with metformin or a thiazolidinedione (pioglitazone, rosiglitazone), leading to a significant improvement in glycaemic control without an increased risk of hypoglycaemia or any other adverse event in patients with T2DM. Finally, the absence of drug-drug interactions in clinical trials in healthy subjects requires further evidence from large-scale studies, including typical subjects with T2DM - in particular, multimorbid and geriatric patients receiving polypharmacy.

Efficacy and safety of saxagliptin in combination with metformin compared with sitagliptin in combination with metformin in adult patients with type 2 diabetes mellitus

BACKGROUND

Dipeptidyl peptidase-4 inhibitors improve glycaemic control in patients with type 2 diabetes mellitus when used as monotherapy or in combination with other anti-diabetic drugs (metformin, sulphonylurea, or thiazolidinedione). This 18-week, phase 3b, multicentre, double-blind, noninferiority trial compared the efficacy and safety of two dipeptidyl peptidase-4 inhibitors, saxagliptin and sitagliptin, in patients whose glycaemia was inadequately controlled with metformin.

METHODS

Adult type 2 diabetes mellitus patients (N = 801) with glycated haemoglobin (HbA(1c)) 6.5-10% on stable metformin doses (1500-3000 mg/day) were randomized 1 : 1 to add-on 5 mg saxagliptin or 100 mg sitagliptin once daily for 18 weeks. The primary efficacy analysis was a comparison of the change from baseline HbA(1c) at week 18 in per-protocol patients. Noninferiority was concluded if the upper limit of the two-sided 95% confidence interval of the HbA(1c) difference between treatments was < 0.3%.

RESULTS

The adjusted mean changes in HbA(1c) following the addition of saxagliptin or sitagliptin to stable metformin therapy were - 0.52 and - 0.62%, respectively. The between-group difference was 0.09% (95% confidence interval, - 0.01 to 0.20%), demonstrating noninferiority. Both treatments were generally well tolerated; incidence and types of adverse events were comparable between groups. Hypoglycaemic events, mostly mild, were reported in approximately 3% of patients in each treatment group. Body weight declined by a mean of 0.4 kg in both groups.

CONCLUSIONS

Saxagliptin added to metformin therapy was effective in improving glycaemic control in patients with type 2 diabetes mellitus inadequately controlled by metformin alone; saxagliptin plus metformin was noninferior to sitagliptin plus metformin, and was generally well tolerated.

Pharmacokinetics of dipeptidylpeptidase-4 inhibitors

Type 2 diabetes (T2DM) is a complex disease combining defects in insulin secretion and insulin action. New compounds have been developed for improving glucose-induced insulin secretion and glucose control, without inducing hypoglycaemia or weight gain. Dipeptidylpeptidase-4 (DPP-4) inhibitors are new oral glucose-lowering agents, so-called incretin enhancers, which may be used as monotherapy or in combination with other antidiabetic compounds. Sitagliptin, vildaglipin and saxagliptin are already on the market in many countries, either as single agents or in fixed-dose combined formulations with metformin. Other DPP-4 inhibitors, such as alogliptin and linagliptin, are currently in late phase of development. The present paper summarizes and compares the main pharmacokinetics (PK) properties, that is, absorption, distribution, metabolism and elimination, of these five DPP-4 inhibitors. Available data were obtained in clinical trials performed in healthy young male subjects, patients with T2DM, and patients with either renal insufficiency or hepatic impairment. PK characteristics were generally similar in young healthy subjects and in middle-aged overweight patients with diabetes. All together gliptins have a good oral bioavailability which is not significantly influenced by food intake. PK/pharmacodynamics characteristics, that is, sufficiently prolonged half-life and sustained DPP-4 enzyme inactivation, generally allow one single oral administration per day for the management of T2DM; the only exception is vildagliptin for which a twice-daily administration is recommended because of a shorter half-life. DPP-4 inhibitors are in general not substrates for cytochrome P450 (except saxagliptin that is metabolized via CYP 3A4/A5) and do not act as inducers or inhibitors of this system. Several metabolites have been documented but most of them are inactive; however, the main metabolite of saxagliptin also exerts a significant DPP-4 inhibition and is half as potent as the parent compound. Renal excretion is the most important elimination pathway, except for linagliptin whose metabolism in the liver appears to be predominant. PK properties of gliptins, combined with their good safety profile, explain why no dose adjustment is necessary in elderly patients or in patients with mild to moderate hepatic impairment. As far as patients with renal impairment are concerned, significant increases in drug exposure for sitagliptin and saxagliptin have been reported so that appropriate reductions in daily dosages are recommended according to estimated glomerular filtration rate. The PK characteristics of DPP-4 inhibitors suggest that these compounds are not exposed to a high risk of drug-drug interactions. However, the daily dose of saxagliptin should be reduced when coadministered with potent CYP 3A4 inhibitors. In conclusion, besides their pharmacodynamic properties leading to effective glucose-lowering effect without inducing hypoglycaemia or weight gain, DPP-4 inhibitors show favourable PK properties, which contribute to a good efficacy/safety ratio for the management of T2DM in clinical practice.

Bariatric surgery in patients with type 2 diabetes: benefits, risks, indications and perspectives

Obesity plays a key role in the pathophysiology of type 2 diabetes (T2DM), and weight loss is a major objective, although difficult to achieve with medical treatments. Bariatric surgery has proven its efficacy in obtaining marked and sustained weight loss, and is also associated with a significant improvement in glucose control and even diabetes remission. Roux-en-Y gastric bypass appears to be more effective in diabetic patients than the restrictive gastroplasty procedure. This may be explained not only by greater weight reduction, but also by specific hormonal changes. Indeed, increased levels of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) may lead to improved beta-cell function and insulin secretion as well as reduced insulin resistance associated with weight loss. The presence of T2DM in obese individuals is a further argument to propose bariatric surgery, and even more so when diabetes is difficult to manage by medical means and other weight-related complications may occur. Bariatric surgery is associated with a better cardiovascular prognosis and reduced mortality, even though acute and long-term complications are present. The observation that surgical rerouting of nutrients triggers changes in the release of incretin hormones that, in turn, ameliorate the diabetic state in the absence of weight loss has led to the recent development of innovative surgical procedures. Thus, bariatric surgery may be said to be progressing towards so-called 'metabolic surgery', which merits further evaluation in patients with T2DM within a multidisciplinary approach that involves both surgeons and endocrinologists.

Matcha, a powdered green tea, ameliorates the progression of renal and hepatic damage in type 2 diabetic OLETF rats

Matcha, a powdered green tea produced by grinding with a stone mill, has been popularly used in the traditional tea ceremony and foods in Japan. Matcha is well known to be richer in some nutritional elements and epigallocatechin 3-O-gallate than other green teas. In our previous study, epigallocatechin 3-O-gallate exhibited protective effects against renal damage in a rat model of diabetic nephropathy. In the present study, we investigated the preventive effects of Matcha (50, 100, or 200 mg/kg/day) on the progression of hepatic and renal damage in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. OLETF rats were orally administered Matcha for 16 weeks, and we assessed biochemical parameters in the serum, liver, and kidney and expression levels of major products of advanced glycation end products (AGEs), N(6)-(carboxylmethyl)lysine (CML) and N(6)-(carboxylethyl)lysine (CEL), receptor for AGE (RAGE), and sterol regulatory element binding proteins (SREBPs)-1 and -2. Serum total protein levels were significantly increased by Matcha administration, whereas the serum albumin and glycosylated protein levels as well as the renal glucose and triglyceride levels were only slightly or not at all affected. However, Matcha treatment significantly lowered the glucose, triglyceride, and total cholesterol levels in the serum and liver, renal AGE levels, and the serum thiobarbituric acid-reactive substances levels. In addition, Matcha supplementation resulted in decreases in the renal CML, CEL, and RAGE expressions as well as an increase in hepatic SREBP-2 expression, but not that of SREBP-1. These results suggest that Matcha protects against hepatic and renal damage through the suppression of renal AGE accumulation, by decreases in hepatic glucose, triglyceride, and total cholesterol levels, and by its antioxidant activities.

[Diabetes and second-generation (atypical) antipsychotics]

Schizophrenia is a common psychiatric illness (1% of the general population), characterized by the association of positive and negative symptoms and cognitive disorders. Antipsychotics, typical or atypical, are known to induce in patients with schizophrenia weight gain and abnormalities in glucose and lipid metabolisms. These modifications, in addition to metabolic risk factors, intrinsic to the psychiatric illness (physical inactivity, smoking, diabetes), increase the risk of cardiovascular complications. Some antipsychotics are associated with a higher risk of metabolic disorders. Before starting such a medication, all risk factors must be taken into account. In case of even effectiveness, one should consider the risk of inducing metabolic disorders, as well as the intrinsic risk factors of the patient, in order to prescribe the medication associated with the lower metabolic risk. Regarding iatrogenic diabetes, the risk of occurrence seems different, depending on the molecules, being more marked for clozapine, olanzapine, risperidone, quietapine then amisulpride, aripiprazole and finally ziprasidone. The physiopathology seems to involve both an increase in insulin resistance and an alteration of insulin secretion. Nevertheless, the benefit/risk often remains largely in favour of treatment, the atypical antipsychotics are at least equally effective and better tolerated on the cognitive and neurological functions than conventional antipsychotics being. They have particularly far fewer extrapyramidal effects. The reversibility of pathologies induced by atypical antipsychotics led to the formulation of guidelines, leading to regular clinical and biological follow-up.

Use of cannabinoid CB1 receptor antagonists for the treatment of metabolic disorders

Abdominal obesity is associated with numerous metabolic abnormalities, including insulin resistance, impaired glucose tolerance/type-2 diabetes, and atherogenic dyslipidaemia with low high-density lipoprotein (HDL) cholesterol, high triglycerides, and increased small dense low-density lipoprotein (LDL) cholesterol. A proportion of these metabolic disorders may be attributed to increased endocannabinoid activity. The selective cannabinoid 1 (CB1) receptor antagonist rimonabant has been shown to reduce body weight, waist circumference, insulin resistance, triglycerides, dense LDL, C-reactive protein (CRP), and blood pressure, and to increase HDL and adiponectin concentrations in both non-diabetic and diabetic overweight/obese patients. Besides an improvement in glucose tolerance in non-diabetic subjects, a reduction of 0.5-0.7% in haemoglobin A1C (HbA(1c)) levels was consistently observed in various groups of patients with type-2 diabetes. Almost half the metabolic changes could not be explained by weight loss, supporting direct peripheral effects of rimonabant. Ongoing studies should demonstrate whether improved metabolic disorders with CB1 receptor antagonists (rimonabant, taranabant, etc.) would translate into fewer cardiovascular complications among high-risk individuals.

New therapeutic approaches in type 2 diabetes

Type 2 diabetes is a progressive chronic disease resulting from a dynamic interaction between defects in insulin secretion and insulin action. New molecules have recently been launched and many others are under clinical investigation. Besides classical sulfonylureas and glinides, new insulin secretagogues are now available, which target the incretin gut hormone glucagon-like peptide-1 (GLP-1). Indeed, oral incretin enhancers acting as antagonists of the enzyme DPP-4 (dipeptidylpeptidase-4), which inactivates natural GLP-1,and injectable incretin mimetics (exenatide) or analogues (liraglutide), which reproduce the actions of GLP-1 while resisting to DPP-4, represent new opportunities to stimulate insulin secretion, without increasing the risk of hypoglycaemia and weight gain. Among insulin sensitizers, metformin remains unequivocally the first drug of choice for the treatment of type 2 diabetes, whereas promising drugs as thiazolidinediones (glitazones) were recently challenged because of various safety issues. When insulin is required, insulin analogues, both short-acting and basal ones, may offer some advantages regarding better control of postprandial hyperglycaemia, reduced risk of hypoglycaemia and/or lower weight gain in patients with type 2 diabetes. Emphasis should be put on early detection and intensive management of type 2 diabetes, individualized glucose lowering treatments and goals, stepwise pharmacological strategy avoiding therapeutic inertia, and multiple cardiovascular risk--targeted approach.

CB1 receptor blockade and its impact on cardiometabolic risk factors: overview of the RIO programme with rimonabant

Rimonabant, the first selective CB(1) receptor antagonist in clinical use, has been extensively investigated in the Rimonabant in Obesity (RIO) programme, comprising four 1-2 year placebo-controlled randomised clinical trials recruiting more than 6600 overweight/obese patients with or without co-morbidities. Rimonabant 20 mg daily consistently reduced body weight, waist circumference, triglycerides, blood pressure, insulin resistance and C-reactive protein levels, and increased HDL cholesterol concentrations in both non-diabetic and type-2 diabetic overweight/obese patients. Adiponectin levels were increased, an effect that correlated with HDL cholesterol augmentation, while small dense LDL cholesterol levels were decreased in patients receiving rimonabant 20 mg compared with those receiving placebo in RIO Lipids. Furthermore, in RIO Diabetes, a 0.7% reduction in glycated haemoglobin (HbA1c) levels was observed in metformin- or sulphonylurea-treated patients with type-2 diabetes, an effect recently confirmed in the 6-month SERENADE (Study Evaluating Rimonabant Efficacy in drug-NAive DiabEtic patients) trial in drug-naive diabetic patients. Almost half of metabolic changes occurred beyond weight loss, in agreement with direct peripheral effects. The positive effects observed after 1 year were maintained after 2 years. Rimonabant was generally well-tolerated, but with a slightly higher incidence of depressed mood disorders, anxiety, nausea and dizziness compared with placebo. In clinical practice, rimonabant has to be prescribed to the right patient, i.e. overweight/obese subjects with cardiometabolic risk factors and with no major depressive illness and/or ongoing antidepressive treatment, in order to both maximise efficacy and minimise safety issues. New trials are supposed to confirm the potential role of rimonabant in patients with abdominal adiposity, atherogenic dyslipidaemia and/or type-2 diabetes, i.e. at high cardiometabolic risk.

Cannabinoid-1 receptor antagonists in type-2 diabetes

Type-2 diabetes is closely related to abdominal obesity and is generally associated with other cardiometabolic risk factors, resulting in a risk of major cardiovascular disease. Several animal and human observations suggest that the endocannabinoid system is over-active in the presence of abdominal obesity and/or diabetes. Both central and peripheral endocannabinoid actions, via the activation of CB1 receptors, promote weight gain and associated metabolic changes. Rimonabant, the first selective CB(1) receptor blocker in clinical use, has been shown to reduce body weight, waist circumference, triglycerides, blood pressure, insulin resistance index and C-reactive protein levels, and to increase high-density lipoprotein (HDL) cholesterol and adiponectin concentrations in both non-diabetic and diabetic overweight/obese patients. In addition, a 0.5-0.7% reduction in HbA1c levels was observed in metformin- or sulphonylurea-treated patients with type-2 diabetes and in drug-naïve diabetic patients. Almost half of the metabolic changes, including HbA1c reduction, could not be explained by weight loss, suggesting that there are direct peripheral effects. Rimonabant was generally well-tolerated, and the safety profile was similar in diabetic and non-diabetic patients, with a higher incidence of depressed mood disorders, nausea and dizziness. In conclusion, the potential role of rimonabant in overweight/obese patients with type-2 diabetes and at high risk of cardiovascular disease deserves much consideration.

Cross-sectional association between BMI, glycemic control and energy intake in Japanese patients with type 2 diabetes. Analysis from the Japan Diabetes Complications Study

Although, weight loss is associated with improved glycemic control in diabetic patients, the relationships between patient weight, daily energy intake (EI), and glycemic or other control status have been poorly investigated. Baseline characteristics of the Japan Diabetes Complications Study, a representative cohort of Japanese diabetic patients, were used for quartile analysis stratified according to patient body mass index (BMI) and EI. Despite a 1.4-fold discrepancy in BMI between the highest and the lowest quartiles, no significant linear trend in HbA(1C) levels or EI between quartiles was seen, although, waist/hip ratio, blood pressure, total cholesterol and triglycerides increased and HDL cholesterol decreased with the increase in BMI. Quartile analysis, according to EI, revealed a 1.8-fold elevation in EI between the lowest and the highest quartile. Nevertheless, the differences in patient BMI between the lowest and the highest quartile were no more than 3% and there were no significant linear trends among the four quartiles in most parameters including HbA(1C), blood pressure, serum lipids. These results revealed only very limited cross-sectional correlations among BMI, EI and other parameters suggesting that it is necessary to consider much wider variations in ideal weight and optimal dietary prescription when making assessments of diabetic patients.

Metformin and body weight

Most patients with type 2 diabetes are overweight or obese, overweight or obesity increases the risk of developing type 2 diabetes and obesity per se is strongly associated with multiple cardiometabolic risk factors. However, many antidiabetic treatments increase body weight. The oral antidiabetic agent, metformin, has been evaluated in hundreds of clinical studies in diverse patient populations during approximately five decades of clinical use. This review summarizes the effects of metformin on body weight, with special reference to studies of longer duration (>/=6 months) as both diabetes and obesity are long-term conditions. Approximately half of studies in drug-naive type 2 diabetic patients demonstrated significant weight loss with metformin compared with baseline or comparator drugs, although pooled analyses have suggested no significant effect versus placebo. Similarly, metformin has been shown to induce weight loss in obese nondiabetic populations, although studies of long duration in this population are scarce. Metformin does appear to mitigate the adverse effects of insulin on body weight. The weight-neutral or weight-sparing effects of metformin constitute a therapeutic advantage in diabetes management where other first-line oral antidiabetic treatments often promote clinically significant weight gain.

Antidiabetic medications in overweight/obese patients with type 2 diabetes: drawbacks of current drugs and potential advantages of incretin-based treatment on body weight

The vast majority of patients with type 2 diabetes are overweight or obese. Lifestyle intervention to lose weight is recommended in most diabetic patients to improve glycaemic control and reduce associated risk factors for microvascular and macrovascular complications. Even modest weight loss can significantly improve glucose homeostasis and lessen cardiometabolic risk factors, although achieving this level of weight reduction remains difficult for many patients. Complicating the matter, many agents used to target hyperglycaemia are associated with weight gain, making management of overweight or obese patients with type 2 diabetes quite challenging. Incretin-based therapies with the new classes of glucagon-like peptide-1 mimetics (e.g. exenatide, liraglutide) and dipeptidyl peptidase 4 (DPP-4) inhibitors (e.g. sitagliptin, vildagliptin) may be of particular value in the treatment of overweight/obese type 2 diabetic patients because of their efficacy in improving glycaemic control and their favourable or neutral effects on body weight. In addition, DPP-4 inhibitors have a low risk for causing hypoglycaemia, undesirable gastrointestinal effects, or other prominent adverse effects that might limit their use. These classes of drugs hold promise for the treatment of type 2 diabetes, alone or in combination with other classes of antidiabetic agents.

Drug-drug and food-drug pharmacokinetic interactions with new insulinotropic agents repaglinide and nateglinide

This review describes the current knowledge on drug-drug and food-drug interactions with repaglinide and nateglinide. These two meglitinide derivatives, commonly called glinides, have been developed for improving insulin secretion of patients with type 2 diabetes mellitus. They are increasingly used either in monotherapy or in combination with other oral antihyperglycaemic agents for the treatment of type 2 diabetes. Compared with sulfonylureas, glinides have been shown to (i) provide a better control of postprandial hyperglycaemia, (ii) overcome some adverse effects, such as hypoglycaemia, and (iii) have a more favourable safety profile, especially in patients with renal failure. The meal-related timing of administration of glinides and the potential influence of food and meal composition on their bioavailability may be important. In addition, some food components (e.g. grapefruit juice) may cause pharmacokinetic interactions. Because glinides are metabolised via cytochrome P450 (CYP) 3A4 isoenzyme, they are indeed exposed to pharmacokinetic interactions. In addition to CYP3A4, repaglinide is metabolised via CYP2C8, while nateglinide metabolism also involves CYP2C9. Furthermore, both compounds and their metabolites may undergo specialised transport/uptake in the intestine, another source of pharmacokinetic interactions. Clinically relevant drug-drug interactions are those that occur when glinides are administered together with other glucose-lowering agents or compounds widely coadministered to diabetic patients (e.g. lipid-lowering agents), with drugs that are known to induce (risk of lower glinide plasma levels and thus of deterioration of glucose control) or inhibit (risk of higher glinide plasma levels leading to hypoglycaemia) CYP isoenzymes concerned in their metabolism, or with drugs that have a narrow efficacy : toxicity ratio. Pharmacokinetic interactions reported in the literature appear to be more frequent and more important with repaglinide than with nateglinide. Rifampicin (rifampin) reduced repaglinide area under the plasma concentration-time curve (AUC) by 32-85% while it reduced nateglinide AUC by almost 25%. Reported increases in AUCs with coadministration of drugs inhibiting CYP isoenzymes never exceeded 80% for repaglinide (except with ciclosporin and with gemfibrozil) and 50% for nateglinide. Ciclosporin more than doubled repaglinide AUC (+144%), a finding that should raise caution when using these two drugs in combination. The most impressive pharmacokinetic interaction was reported with combined administration of gemfibrozil (a strong CYP2C8 inhibitor) and repaglinide (8-fold increase in repaglinide AUC). Although no studies have been performed in patients with type 2 diabetes, the latter combination should be avoided in clinical practice.

Pharmacokinetic interactions with thiazolidinediones

Type 2 diabetes mellitus is a complex disease combining defects in insulin secretion and insulin action. New compounds called thiazolidinediones or glitazones have been developed for reducing insulin resistance. After the withdrawal of troglitazone because of liver toxicity, two compounds are currently used in clinical practice, rosiglitazone and pioglitazone. These compounds are generally used in combination with other pharmacological agents. Because they are metabolised via cytochrome P450 (CYP), glitazones are exposed to numerous pharmacokinetic interactions. CYP2C8 and CYP3A4 are the main isoenzymes catalysing biotransformation of pioglitazone (as with troglitazone), whereas rosiglitazone is metabolised by CYP2C9 and CYP2C8. For both rosiglitazone and pioglitazone, the most relevant interactions have been described in healthy volunteers with rifampicin (rifampin), which results in a significant decrease of area under the plasma concentration-time curve [AUC] (54-65% for rosiglitazone, p<0.001; 54% for pioglitazone, p<0.001), and with gemfibrozil, which results in a significant increase of AUC (130% for rosiglitazone, p<0.001; 220-240% for pioglitazone, p<0.001). The relevance of such drug-drug interactions in patients with type 2 diabetes remains to be evaluated. However, in the absence of clinical data, it is prudent to reduce the dosage of each glitazone by half in patients treated with gemfibrozil. Conversely, rosiglitazone and pioglitazone do not seem to significantly affect the pharmacokinetics of other compounds. Although some food components have also been shown to potentially interfere with drugs metabolised with the CYP system, no published study deals specifically with these possible CYP-mediated food-drug interactions with glitazones.

Endocannabinoid blockade for improving glycemic control and lipids in patients with type 2 diabetes mellitus

Rimonabant significantly reduces weight and waist circumference and improves dyslipidemias in overweight and obese patients without diabetes mellitus. Numerous other metabolic changes, including reduced prevalence of the metabolic syndrome and associated cardiovascular disease (CVD) risk factors, reduced fasting glucose, and elevated adiponectin, have been demonstrated with the administration of rimonabant. The Rimonabant-in-Obesity (RIO)-Diabetes trial studied the safety and efficacy of rimonabant in overweight and obese patients with type 2 diabetes who were treated with metformin or sulfonylureas. RIO-Diabetes was a 1-year, randomized, double-blind, placebo-controlled, parallel-group study of 1,047 overweight/obese patients with type 2 diabetes in 151 centers in 11 countries. The body mass index of participants ranged from 27 to 40. Glycosylated hemoglobin (HbA1c) at screening ranged from 6.5% to 10.0%. All patients were receiving either metformin or sulfonylurea therapy and were asked to follow a hypocaloric diet (600 kcal/day deficit [1 kcal = 4.2 kJ]) for the duration of the trial. After a 4-week placebo plus diet run-in period, patients were randomized to receive placebo or rimonabant 5 mg or 20 mg once daily. At 1 year, absolute change in weight from baseline in the intention-to-treat, last observation carried forward analysis of the rimonabant 5 mg and 20 mg groups, respectively, was loss of 2.3 kg and 5.3 kg compared with 1.4 kg in the placebo group (P = 0.013 and P <0.001, respectively). Waist circumference was significantly decreased in the rimonabant 5-mg and 20-mg groups by 2.9 cm and 5.2 cm compared with 1.9 cm in the placebo group (P = 0.034 and P <0.001, respectively). HbA1c reductions of 0.1% and 0.6% were significant in the rimonabant 5-mg and 20-mg groups (P = 0.034 and P <0.001, respectively). Some 57% of the improvements in HbA(1c) and high-density lipoprotein cholesterol could not be attributed to observed weight loss. Compared with placebo, rimonabant 20 mg also demonstrated significant improvements in the prevalence of metabolic syndrome and improvement in its constituents, as well as systolic blood pressure and C-reactive protein levels (assay by ICON Laboratories, Farmingdale, NY and Dublin, Ireland). Rimonabant is the first selective cannabinoid1 blocker studied for type 2 diabetes and associated CVD risk factor therapy. Its ability to improve the numerous metabolic pathologies associated with diabetes and CVD risk and concomitantly to reduce weight and waist circumference introduces a strongly positive new dynamic in type 2 diabetes treatment. Its multifactorial mechanisms warrant further investigation and may provide insights into other pathologies.

Efficacy and tolerability of rimonabant in overweight or obese patients with type 2 diabetes: a randomised controlled study

BACKGROUND

Rimonabant, a selective cannabinoid type 1 receptor blocker, reduces bodyweight and improves cardiovascular and metabolic risk factors in non-diabetic overweight or obese patients. The aim of the RIO-Diabetes trial was to assess the efficacy and safety of rimonabant in overweight or obese patients with type 2 diabetes that was inadequately controlled by metformin or sulphonylureas.

METHODS

1047 overweight or obese type 2 diabetes patients (body-mass index 27-40 kg/m2) with a haemoglobin A1c (HbA1c) concentration of 6.5-10.0% (mean 7.3% [SD 0.9] at baseline) already on metformin or sulphonylurea monotherapy were given a mild hypocaloric diet and advice for increased physical activity, and randomly assigned placebo (n=348), 5 mg/day rimonabant (360) or 20 mg/day rimonabant (339) for 1 year. Two individuals in the 5 mg/day group did not receive double-blind treatment and were thus not included in the final analysis. The primary endpoint was weight change from baseline after 1 year of treatment. Analyses were done on an intention-to-treat basis. This trial is registered at ClinicalTrials.gov, number NCT00029848.

FINDINGS

692 patients completed the 1 year follow-up; numbers in each group after 1 year were much the same. Weight loss was significantly greater after 1 year in both rimonabant groups than in the placebo group (placebo: -1.4 kg [SD 3.6]; 5 mg/day: -2.3 kg [4.2], p=0.01 vs placebo; 20 mg/day: -5.3 kg [5.2], p<0.0001 vs placebo). Rimonabant was generally well tolerated. The incidence of adverse events that led to discontinuation was slightly greater in the 20 mg/day rimonabant group, mainly due to depressed mood disorders, nausea, and dizziness.

INTERPRETATION

These data indicate that 20 mg/day rimonabant, in combination with diet and exercise, can produce a clinically meaningful reduction in bodyweight and improve HbA1c and a number of cardiovascular and metabolic risk factors in overweight or obese patients with type 2 diabetes inadequately controlled by metformin or sulphonylureas.

Drug interactions of clinical importance with antihyperglycaemic agents: an update

Because management of type 2 diabetes mellitus usually involves combined pharmacological therapy to obtain adequate glucose control and treatment of concurrent pathologies (especially dyslipidaemia and arterial hypertension), drug-drug interactions must be carefully considered with antihyperglycaemic drugs. Additive glucose-lowering effects have been extensively reported when combining sulphonylureas (or the new insulin secretagogues, meglitinide derivatives, i.e. nateglinide and repaglinide) with metformin, sulphonylureas (or meglitinide derivatives) with thiazolidinediones (also called glitazones) and the biguanide compound metformin with thiazolidinediones. Interest in combining alpha-glucosidase inhibitors with either sulphonylureas (or meglitinide derivatives), metformin or thiazolidinediones has also been demonstrated. These combinations result in lower glycosylated haemoglobin (HbA(1c)), fasting glucose and postprandial glucose levels than with either monotherapy. Even if modest pharmacokinetic interferences have been reported with some combinations, they do not appear to have important clinical consequences. No significant adverse effects, except a higher risk of hypoglycaemic episodes that may be attributed to better glycaemic control, occur with any combination. Challenging the classical dual therapy with sulphonylurea plus metformin, there is a recent trend to use alternative dual combinations (sulphonylurea plus thiazolidinedione or metformin plus thiazolidinedione). In addition, triple therapy with the addition of a thiazolidinedione to the metformin-sulphonylurea combination has been recently evaluated and allows glucose targets to be reached before insulin therapy is considered. This triple therapy appears to be safe, with no deleterious drug-drug interactions being reported so far.Potential interferences may also occur between glucose-lowering agents and other drugs, and such drug-drug interactions may have important clinical implications. Relevant pharmacological agents are those that are widely coadministered in diabetic patients (e.g. lipid-lowering agents, antihypertensive agents); those that have a narrow efficacy/toxicity ratio (e.g. digoxin, warfarin); or those that are known to induce (rifampicin [rifampin]) or inhibit (fluconazole) the cytochrome P450 (CYP) system. Metformin is currently a key compound in the pharmacological management of type 2 diabetes, used either alone or in combination with other antihyperglycaemics. There are no clinically relevant metabolic interactions with metformin, because this compound is not metabolised and does not inhibit the metabolism of other drugs. In contrast, sulphonylureas, meglitinide derivatives and thiazolidinediones are extensively metabolised in the liver via the CYP system and thus, may be subject to drug-drug metabolic interactions. Many HMG-CoA reductase inhibitors (statins) are also metabolised via the CYP system. Even if modest pharmacokinetic interactions may occur, it is not clear whether drug-drug interactions between oral antihyperglycaemic agents and statins may have clinical consequences regarding both efficacy and safety. In contrast, a marked pharmacokinetic interference has been reported between gemfibrozil and repaglinide and, to a lesser extent, between gemfibrozil and rosiglitazone. This leads to a drastic increase in plasma concentrations of each antihyperglycaemic agent when they are coadministered with the fibric acid derivative, and an increased risk of adverse effects. Some antihypertensive agents may favour hypoglycaemic episodes when co-prescribed with sulphonylureas or meglitinide derivatives, especially ACE inhibitors, but this effect seems to result from a pharmacodynamic drug-drug interaction rather than from a pharmacokinetic drug-drug interaction. No, or only modest, interferences have been described with glucose-lowering agents and other pharmacological compounds such as digoxin or warfarin. The effects of inducers or inhibitors of CYP isoenzymes on the metabolism and pharmacokinetics of the glucose-lowering agents of each pharmacological class has been tested. Significantly increased (with CYP inhibitors) or decreased (with CYP inducers) plasma levels of sulphonylureas, meglitinide derivatives and thiazolidinediones have been reported in healthy volunteers, and these pharmacokinetic changes may lead to enhanced or reduced glucose-lowering action, and thus hypoglycaemia or worsening of metabolic control, respectively. In addition, some case reports have evidenced potential drug-drug interactions with various antihyperglycaemic agents that are usually associated with a higher risk of hypoglycaemia.

Comparison of body fat composition and serum adiponectin levels in diabetic obesity and non-diabetic obesity

OBJECTIVE

Clinical aspects of diabetes and obesity are somewhat different, even at similar levels of insulin resistance. The purpose of this study was to determine differences in body fat distribution and serum adiponectin concentrations in diabetic and non-diabetic obese participants. We were also interested in identifying the characteristics of insulin resistance in these two groups, particularly from the standpoint of adiponectin.

RESEARCH METHODS AND PROCEDURES

Adiponectin concentrations of 112 type 2 diabetic obese participants and 124 non-diabetic obese participants were determined. Abdominal adipose tissue areas and midthigh skeletal muscle areas were measured by computed tomography. A homeostasis model assessment of the insulin resistance score was calculated to assess insulin sensitivity. The relationships among serum adiponectin, body fat distribution, and clinical characteristics were also analyzed.

RESULTS

Both abdominal subcutaneous and visceral fat areas were higher in the non-diabetic obese group, whereas midthigh low-density muscle area was higher in the diabetic obese group. The homeostasis model assessment of the insulin resistance score was similar between groups, whereas serum adiponectin was lower in the diabetic obese group. Abdominal visceral fat (beta = -0.381, p = 0.012) was a more important predictor of adiponectin concentration than low-density muscle (beta = -0.218, p = 0.026) in cases of non-diabetic obesity, whereas low-density muscle (beta = -0.413, p = 0.013) was a better predictor of adiponectin level than abdominal visceral fat (beta = - 0.228, p = 0.044) in diabetic obese patients.

DISCUSSION

Therefore, factors involved in pathophysiology, including different serum adiponectin levels and body fat distributions, are believed to be responsible for differences in clinical characteristics, even at similar levels of insulin resistance in both diseases.

Diabetes mellitus in the elderly: insulin resistance and/or impaired insulin secretion?

Elderly people are more glucose intolerant and insulin resistant than young individuals, and many of them will develop type 2 diabetes. It remains, however, controversial whether this decrease in function is due to an inevitable consequence of "biological aging" or due to environmental or lifestyle variables. Indeed, increased adiposity/altered fat distribution, decreased fat free mass/abnormal muscle composition, poor dietary habits and physical inactivity all contribute to reduce insulin sensitivity. Insulin resistance in elderly people appears to predominate in skeletal muscle, whereas hepatic glucose output seems to be almost unaffected. Several abnormalities in islet beta-cell and insulin secretion were also pointed out in elderly people such as increased amyloid deposition and decreased amylin secretion, impaired insulin secretion pulsatility, decreased insulin sensitivity of pancreatic beta-cells to insulinotropic gut hormones and diminished insulin response to non-glucose stimuli such as arginine. Controversial results were reported concerning the effects of aging on absolute insulin secretion in response to oral or intravenous glucose. However, insulin secretion appears to decrease with age, with significantly diminished beta-cell sensitivity and acute insulin response to glucose, provided it is analyzed relative to concomitant decreased insulin sensitivity. Thus, there is an interplay between decreased insulin secretion and increased insulin resistance that largely explains the abnormal glucose metabolism seen in elderly. Weight loss, especially reduction of abdominal adiposity, and increased physical activity may contribute to improve insulin sensitivity and glucose tolerance, and prevent the development of type 2 diabetes in elderly people.

Effects of okchun-san, a herbal formulation, on blood glucose levels and body weight in a model of Type 2 diabetes

The effective control of blood glucose is the key to preventing or reversing diabetic complications. In this study, we examined the effects of Okchun-San (OCS), a Korean herbal medicine formula, on the blood glucose levels in diabetic C57BL/KsJ db/db mice. Herbal medicines were prepared from dried herbs by adding Coicis semen (OCS-C) or Oryzae semen (OCS-O). The experimental animals were divided into a control group and three sample groups; the sample groups received OCS-C (200 mg/kg), OCS-O (200 mg/kg), or acarbose (5 mg/kg) orally once a day for 12 days. On days 5 and 12, the fasting blood glucose levels of vehicle-treated db/db mice were significantly higher than day 0, while those of OCS-C, OCS-O, or acarbose-treated mice had not increased compared to the control group (p<0.01). During intraperitoneal glucose tolerance test (IPGTT), OCS-C group showed improved glucose sensitivity compared to the control group. These results suggest that OCS-C can be useful as an anti-diabetic therapy for Type 2 diabetic patients by lowering the blood glucose level.

Combined thiazolidinedione-insulin therapy: should we be concerned about safety?

Thiazolidinediones, also called glitazones, are insulin sensitisers that act as agonists of the peroxisome proliferator-activated receptors-gamma (PPARgamma). After the withdrawal of troglitazone due to hepatotoxicity, only pioglitazone and rosiglitazone can be used for treating patients with type 2 diabetes mellitus, either as monotherapy or in combination with metformin or with sulphonylureas (or glinides). The combination of glitazones with insulin is also appealing, as it allows improvement of glycaemic control while decreasing the daily insulin requirement. Insulin dosage has to be adjusted regularly to avoid hypoglycaemic episodes. However, some concerns have been raised about such combined glitazone-insulin therapy because it may favour weight gain due to both enhanced adipogenesis and fluid retention. Such adverse effects are commonly observed in all diabetic individuals receiving glitazones, whatever the mode of use, but they appear to be exacerbated in insulin-treated patients. Body fat gain is a major drawback of treatment with adipogenic compounds such as glitazones. However, some evidence suggests that the fat is redistributed in a favourable direction, that is, from visceral to subcutaneous depots, although no long-term follow-up is yet available. An estimated 2-5% of patients receiving glitazone monotherapy and 5-15% receiving concomitant insulin therapy experience peripheral oedema. Some anecdotal cases of pulmonary oedema have also been reported, especially in insulin-treated patients, although the actual incidence of this complication is unknown. All glitazones increase the intravascular volume by approximately 6-7% in a dose-dependent manner. Rather than a direct effect on cardiac or renal function, fluid retention and tissue oedema seem to be part of a vascular 'leak' syndrome. Such a phenomenon may have greater consequences in patients with type 2 diabetes treated with insulin because such patients are usually older, have had the disease long-term and have worse cardiac or renal function. Additionally, glitazones may potentiate the renal effects of insulin on sodium and water retention. Regardless of the mechanism, it is conceivable that additional fluid retention caused by glitazones may alter the already precarious volume status in patients with underlying cardiac or renal dysfunction, thus leading to oedema and congestive heart failure. Thus, it is prudent to either avoid glitazones or use them cautiously in individuals with impaired cardiac function. Further studies are clearly needed to define the mechanisms of fluid retention associated with glitazone use and to determine the safety of cautious use of these new insulin sensitisers in insulin-treated patients with type 2 diabetes.

Medications as Adjunct Therapy for Weight Loss: Approved and Off-Label Agents in Use

Although a nutritionally balanced, energy-controlled diet and regular exercise form the cornerstone of weight management, supporting therapies may include antiobesity medications when a clinician determines that pharmacologic assistance could contribute to treatment success. The US Food and Drug Administration has approved certain medications for helping achieve weight loss in patients with obesity or overweight who have comorbidities. However, some clinicians prescribe medications not approved for weight loss for this purpose. Evidence from clinical trials indicates that weight loss resulting from the use of many of these off-label pharmaceutical agents is modest, but in a range that correlates with favorable modification of cardiovascular risk factors, and significant when compared with placebo plus diet and lifestyle modification. Clinical trials also demonstrate a slight but significant effect in the weight-maintenance phases following weight loss. Pharmacotherapy alone, without behavior modification, is not effective; patients who respond to medication typically regain weight when the drug is discontinued. The fact that many weight-loss medications are sold over the Internet without a prescription suggests that they are being used without medical supervision. The purpose of this review is to present evidence for and against the obesity medications currently used in clinical practice, and the possible role for these agents in a person's overall weight loss plan.

Assessment of pharmacology and potential anti-obesity properties of H3receptor antagonists/inverse agonists

Histamine is a key neurotransmitter that alters central nervous system functions in both behavioural and homeostatic contexts through its actions on the histamine (H) subreceptors H(1), H(2) and H(3) G-protein-coupled receptors. H(3)receptors have a diverse central nervous system distribution where they function as both homo- and hetero-receptors to modulate the synthesis and/or release of several neurotransmitters. H(3) receptors are constitutively active, which implies that antagonists of H(3) receptors may also function as inverse agonists to alter the basal state of the receptor and uncouple constitutive receptor-G-protein interactions. Reference H(3) antagonists such as thioperamide and ciproxifan, administered either centrally or systemically, have been shown to cause changes in food consumption and/or body weight in proof-of-concept studies. More recently, several non-imidazole-based H(3) antagonists/inverse agonists have also been described with efficacy in at least one animal model of human obesity. Considerable preclinical effort remains necessary before such compounds achieve therapeutic success or failure. Moreover, ongoing research in a number of laboratories has shed new insights into the effects of H(3) ligands in the control of feeding, appetite and body weight, which offer different results and conclusions. The goal of this review is to appraise these findings and forecast whether any H(3) antagonists/inverse agonists will provide clinical utility to treat human obesity.

Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system

Type 2 diabetes mellitus is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of type 2 diabetes is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with type 2 diabetes and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of type 2 diabetes in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of type 2 diabetes: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of type 2 diabetes by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of type 2 diabetes that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of type 2 diabetes.

The M16 mouse: an outbred animal model of early onset polygenic obesity and diabesity

OBJECTIVE

To characterize the phenotypic consequences of long-term selective breeding for rapid weight gain, with an emphasis on obesity and obesity-induced diabetes (diabesity).

RESEARCH METHODS AND PROCEDURES

M16 is the result of long-term selection for 3- to 6-week weight gain from an ICR base population. Experiment 1 characterized males from both lines for body weights (3, 6, and 8 weeks), feed (4 to 8 weeks) and H(2)O (6 to 8 weeks) consumption, and heat loss, body composition, and levels of several plasma proteins at 8 weeks of age. Experiment 2 characterized differences between lines for both sexes at three ages (6, 8, and 16 weeks) and fed two diets (high and normal fat). Body weight, composition, blood glucose, and plasma insulin and leptin levels were evaluated after an 8-hour fast.

RESULTS

At all ages measured, M16 mice were heavier, fatter, hyperphagic, hyperinsulinemic, and hyperleptinemic relative to ICR. M16 males and females were hyperglycemic relative to ICR, with 56% and 22% higher fasted blood glucose levels at 8 weeks of age.

DISCUSSION

M16 mice represent an outbred animal model to facilitate gene discovery and pathway regulation controlling early onset polygenic obesity and type 2 diabetic phenotypes. Phenotypes prevalent in the M16 model, with obesity and diabesity exhibited at a young age, closely mirror current trends in human populations.