Acute effect of orlistat on post-prandial lipaemia and free fatty acids in overweight patients with Type 2 diabetes mellitus

The Role of Anti-Obesity Medication in Prevention of Diabetes and Its Complications

Diabetes is prevalent in obese population, and obesity management is the first step in preventing diabetes. Traditionally, lifestyle modification including reduced-calorie diet, physical activity, and behavior intervention is the core of obesity management. However, pharmacotherapy is frequently required in addition to the lifestyle modification for effective reduction of body weight. There are five classes of anti-obesity medications approved by the U.S. Food and Drug Administration for chronic treatment used in obesity management. As the goal of obesity management is to prevent obesity-related comorbidities, clinical trials were conducted to evaluate the effect of anti-obesity medications on cardiovascular risk factors including hyperglycemia. Orlistat and liraglutide have been tested for their effect on diabetes prevention as a primary outcome. Cardiovascular safety studies were conducted for lorcaserin and liraglutide (as an anti-diabetic medication). In addition, there are many indirect evidences of the role of anti-obesity medications on diabetes prevention and its microvascular and macrovascular complications. This review focused on current evidences of anti-obesity medications related with diabetes, which is a major complication of obesity.

Cardioprotective effect of lipstatin derivative orlistat on normotensive rats submitted to cardiac ischemia and reperfusion

PURPOSE

To evaluate in vivo animal model of cardiac ischemia/reperfusion the cardioprotective activity of pancreatic lipase inhibitor of the orlistat.

METHODS

Adult male Wistar rats were anesthetized, placed on mechanical ventilation and underwent surgery to induce cardiac I/R by obstructing left descending coronary artery followed by reperfusion to evaluation of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) with pancreatic lipase inhibitor orlistat (ORL). At the end of reperfusion, blood samples were collected for determination of triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), lactate dehydrogenase (LDH), creatine kinase (CK), and creatine kinase-MB (CK-MB).

RESULTS

Treatment with ORL has been able to decrease the incidence of VA, AVB and LET. Besides that, treatment with ORL reduced serum concentrations of CK and LDL, but did not alter the levels of serum concentration of TG, VLDL and HDL.

CONCLUSION

The reduction of ventricular arrhythmias, atrioventricular block, and lethality and serum levels of creatine kinase produced by treatment with orlistat in animal model of cardiac isquemia/reperfusion injury suggest that ORL could be used as an efficient cardioprotective therapeutic strategy to attenuate myocardial damage related to acute myocardial infarction.

Identification of Digestive Enzyme Inhibitors from Ludwigia octovalvis (Jacq.) P.H.Raven

Current antiobesity and antidiabetic tools have been insufficient to curb these diseases and frequently cause side effects; therefore, new pancreatic lipase and α–glucosidase inhibitors could be excellent aids for the prevention and treatment of these diseases. The aim of this study was to identify, quantify, and characterize the chemical compounds with the highest degree of inhibitory activity of these enzymes, contained in a Ludwigia octovalvis hydroalcoholic extract. Chemical purification was performed by liquid–liquid separation and column chromatography. Inhibitory activities were measured in vitro, employing acarbose, orlistat, and a Camellia sinensis hydroalcoholic extract as references. For structural elucidation, Nuclear Magnetic Resonance was carried out, and High Performance Liquid Chromatography was used to quantify the compounds. For α–glucosidases, L. octovalvis hydroalcoholic extract and its ethyl acetate fraction showed half–maximal Inhibitory Concentration (IC₅₀) values of 700 and 250 μg/mL, for lipase, 480 and 718 μg/mL, while C. sinensis showed 260 and 587 μg/mL. The most active compounds were identified as ethyl gallate (1, IC₅₀ 832 μM) and gallic acid (2, IC₅₀ 969 μM); both displayed competitive inhibition of α–glucosidases and isoorientin (3, IC₅₀ 201 μM), which displayed uncompetitive inhibition of lipase. These data could be useful in the development of a novel phytopharmaceutical drug.

Triglyceride Treatment in the Age of Cholesterol Reduction

Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.

Effects of orlistat plus diet on postprandial lipemia and brachial artery reactivity in normolipidemic, obese women with normal glucose tolerance: A prospective, randomized, controlled Study

BACKGROUND

Postprandial lipemia (PPL) is an independent predictor of earlyatherosclerosis and coronary artery disease. It is defined as a postprandial triglyceride (TG) level ≥80% higher than the fasting level. Brachial arterial reactivity (BAR) is used to identify early-phase atherosclerosis. Data concerning whether orlistat improves PPL and endothelial function are lacking.

OBJECTIVE

The aim of this study was to determine the effects of orlistat on PPL and BAR in normolipidemic, obese women with normal glucose tolerance.

METHODS

This prospective, randomized, controlled study was conducted at Baskent University, Ankara, Turkey. Normolipidemic, obese women aged 18 to 65 years with normal glucose tolerance were eligible for screening. On screening, demographic information, anthropomorphic parameters (body mass index [BMI], waist circumference [WC], hip circumference, waist-hip ratio), BAR, laboratory test results (level of insulin resistance assessed using the homeostasis model assessment-insulin resistance [HOMA-IR] index, serum lipid profile, fasting plasma levels of glucose and insulin [FPI]), and oral fat-loading test results were recorded as baseline values. The primary end points were the effects of orlistat + diet on PPL (assessed using the AUC of TG) and BAR. Women found on screening to be PPL positive were randomly assigned in a 2:1 ratio to treatment with orlistat 120 mg TID plus low-calorie diet (600-kcal/d deficit; minimum, 1200 kcal/d) or low-calorie diet only (control) for 12 weeks. After 12 weeks, all of the above assessments were repeated, and AUC values for lipid parameters were calculated as secondary outcome measures. To assess tolerability and compliance, women were monitored by telephone each week and instructed to return every 4 weeks for clinic visits.

RESULTS

Twenty-seven women were identified as PPL positive and assigned to the orlistat + diet group (18 subjects) or the control group (9) (mean [SD] age, 45.9 [2.3] years; mean [SD] weight, 87.4 [2.5] kg; mean [SD] BMI, 36.0 [0.8] kg/m(2)). Treatment with orlistat + diet was associated with significantly greater changes from baseline compared with controls in WC (P= 0.003), fasting and postprandial serum TG levels (P = 0.012 and P < 0.001, respectively), FPI level (P = 0.001), and HOMA-IR index (P < 0.001). Logistic regression analysis found that 12 weeks of treatment with orlistat + diet was associated with a numeric, but statistically non-significant, 4.1-fold change in PPL, which was independent of reductions from baseline in weight and WC. Neither treatment was associated with significant changes from baseline in BAR. The prevalences of gastrointestinal symptoms previously found to be related to orlistat use were statistically similar between the orlistat + diet and control groups (9 [50.0%] vs 3 [33.3%] subjects).

CONCLUSIONS

The results of this small study in normolipidemic, obesewomen with normal glucose tolerance suggest that 12 weeks of treatment with orlistat 120 mg/d plus low-calorie diet was associated with a numeric, but statistically nonsignificant, 4.1-fold change from baseline in PPL, which was independent of reductions from baseline in weight and WC. Treatment with orlistat + diet was associated with significant effects on WC, TG, and level of insulin resistance, but not BAR.

Lactobacillus gasseri SBT2055 reduces postprandial and fasting serum non-esterified fatty acid levels in Japanese hypertriacylglycerolemic subjects

BACKGROUND

Lactobacillus gasseri SBT2055 (LG2055) inhibits dietary fat absorption in rats and exerts preventive effects on abdominal adiposity in rats and humans. The present study aimed to evaluate the effects of LG2055 on postprandial serum lipid responses in Japanese subjects with hypertriacylglycerolemia after the intake of oral fat-loading test (OFLT) meals.

METHODS

We conducted a single-blind, placebo-controlled, within-subject, repeated-measure intervention trial. Twenty subjects initially ingested the fermented milk (FM) without LG2055 for 4 weeks (control FM period), followed by a 4-week washout period, and then consumed FM containing LG2055 for 4 weeks (active FM period). The subjects were asked to consume FM at 200 g/day. At the end of each 4-week period, an 8-h OFLT was conducted. Blood samples were collected at fasting and every hour for 8 h after OFLT meal intake. Thereafter, postprandial serum non-esterified fatty acid (NEFA) and triacylglycerol (TAG) levels and fasting blood parameters were measured.

RESULTS

The OFLT showed that the postprandial serum NEFA levels from 120 to 480 min and the postprandial serum TAG level at 120 min in the active FM period were significantly (P < 0.05) lower than those in the control FM period. The fasting serum NEFA level in the active FM period significantly (P < 0.001) decreased at week 4 from the initial period compared with the control FM period.

CONCLUSIONS

The consumption of probiotic LG2055 reduced postprandial and fasting serum NEFA levels, suggesting its possible contribution to the reduction of the risk for obesity and type 2 diabetes mellitus.

TRIAL REGISTRATION

UMIN000011605.

Effect of orlistat on plasma leptin levels and risk factors for the metabolic syndrome

BACKGROUND

The aim of this research was to assess the impact of treatment with Orlistat 120 mg three times daily on serum leptin levels, weight loss, glycemic control, and cardiovascular risk factors involved in the metabolic syndrome.

METHODS

A 3-month open-labeled prospective study was conducted on 40 patients with the clinical features of the metabolic syndrome divided into two groups-with and without type 2 diabetes mellitus. Twenty type 2 diabetic obese patients (group A) were studied, with BMI of 35.4 +/- 0.9 kg/m(2), as were 20 obese patients without diabetes (group B), with BMI of 36.2 +/- 0.7 kg/m(2). Weight, serum leptin levels, insulin resistance, and cardiovascular risk factors were measured at baseline and at the end of each month.

RESULTS

Patients reduced weight at 8.5 +/- 2.3 kg for men and 5.7 +/- 2.6 kg for women in group A against 7.9 +/- 1.9 kg for men and 5.6 +/- 2.0 kg for women in group B. Plasma leptin levels decreased at 4.5 +/- 1.9 ng/mL for men and 1.9 +/- 0.9 ng/mL for women in group A against 3.8 +/- 2.0 ng/mL for men and 2.8 +/- 1.4 ng/mL for women in group B. The level of insulin resistance measured with HOMA-IR decreased from 4.54 +/- 2.35 to 2.69 +/- 0.86 in group A against 3.98 +/- 1.89 to 2.87 +/- 0.93 in group B. In the lipid parameters, the highest decrease was found in triglycerides levels: 6.1 +/- 2.3 mmol/L for men and 3.5 +/- 2.6 mmol/L for women in group A against 2.1 +/- 1.9 mmol/L for men and 1.8 +/- 0.7 mmol/L for women in group B (all p < 0.05).

CONCLUSIONS

Orlistat beneficially enhances weight loss, contributing to a decrease of serum leptin, insulin resistance level, and cardiovascular risk factors in both groups. An additional beneficial pleotropic effect of Orlistat could be proposed through a reduction of plasma leptin and lipid levels.

Slowly and rapidly digested fat emulsions are equally satiating but their triglycerides are differentially absorbed and metabolized in humans

Little is known about the effect of dietary fat emulsion microstructure on plasma TG concentrations, satiety hormones, and food intake. The aim of this study was to structure dietary fat to slow digestion and flatten postprandial plasma TG concentrations but not increase food intake. Emulsions were stabilized by egg lecithin (control), sodium sterol lactylate, or sodium caseinate/monoglyceride (CasMag) with either liquid oil or a liquid oil/solid fat mixture. In a randomized, double-blind, crossover design, 4 emulsions containing 30 g of fat in a 350-mL preload were consumed by 10 men and 10 women (BMI = 25.1 ± 2.8 kg/m(2); age = 58.8 ± 4.8 y). Pre- and postprandial plasma TG, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) concentrations and food intake were measured. In a second experiment in a subset of the participants (n = 8, 4 men and 4 women), (13)C-labeled mixed TG was incorporated into 2 different emulsions and breath (13)C was measured over 6 h. In the first experiment, the postprandial rise in plasma TG concentrations following the CasMag-stabilized emulsion containing 30% solid fat was lower than all other emulsions at 90 and 120 min (P < 0.05). Plasma CCK (P < 0.0001), GLP-1 (P < 0.01), and PYY (P < 0.001) concentrations were also reduced following this emulsion compared with control. Food intake at a test meal, eaten 3 h after the preload, did not differ among the emulsions. In the second experiment, when measured by the (13)C breath test, 25% of the TG in the CasMag emulsion was absorbed and metabolized compared with control. In conclusion, fat can be structured to decrease its effect on plasma TG concentrations without increasing food intake.

Effects of short-term treatment with orlistat on growth hormone/insulin-like growth factor-I axis in obese post-menopausal women

AIM

Obesity is associated with an altered GH/IGF-I axis status, accounting for the increased cardiovascular risk in obese subjects with GH deficiency. Aim of this randomized, simple-blind, cross-over study was to verify the effectiveness of a short-term treatment with orlistat in reducing non-esterified fatty acid (NEFA) and influencing the endogenous activity of GH/IGF-I axis in obese subjects.

OUTCOME MEASURES

The primary outcome measures were post-prandial lipemia; GH peak after GHRH+arginine; IGF-I; IGF-binding protein (BP)-3, IGF-I/IGFBP-3 ratio. Secondary outcome measures were insulin resistance (IR) indexes (homeostasis model assessment of insulin resistance and Insulin Sensitivity Index).

STUDY DESIGN

Twenty obese post-menopausal women (age: 53.6 ± 6.2; body mass index: 34.1 ± 4.0) were randomized to receive normo-caloric diet plus + orlistat (Roche, UK; 120 mg tid) or normo-caloric diet without the additional treatment. The duration of follow-up was 10 days for each treatment period.

RESULTS

Orlistat induced a weight-independent reduction in post-prandial NEFA levels compared with diet alone, with higher GH peak, IGF-I, and IGF-I/IGFBP3 ratio. GH peak was correlated negatively with postprandial NEFA and positively with IGF-I and IGF-I/IGFBP-3 ratio.

CONCLUSIONS

Orlistat is effective in inducing a weight-independent higher reduction in post-prandial NEFA levels than dietary treatment alone along with increase in GH peak, IGF-I levels, and IGFI/ IGFBP-3 ratio. These results might add a new potential benefit of orlistat in the management of obese subjects.

The effects of ezetimibe and/or orlistat on triglyceride-rich lipoprotein metabolism in obese hypercholesterolemic patients

We investigated the factors influencing triglycerides (TG) reduction during ezetimibe, alone or combined with orlistat, administration. Eighty-six obese hypercholesterolemic subjects were prescribed a low-fat diet and were randomized to ezetimibe (E group), orlistat (O group), or both (OE group) for 6 months. Plasma TG and apolipoprotein (apo) C-III reduction was significantly greater in the combination group compared with monotherapy. Multivariate analysis showed that in E group apoC-III reduction and baseline TG levels were independently positively correlated, whereas baseline apoC-II levels were negatively correlated, with TG lowering. In OE group apoC-III reduction was the only independent contributor to TG reduction.

Effect of antiobesity medications in patients with type 2 diabetes mellitus

Obesity is considered as a major health problem, as its prevalence continuously rises worldwide. One of the common health consequences of obesity is type 2 diabetes mellitus. Therefore, antiobesity management is a prerequisite in treating diabetic patients. Lifestyle modifications combined with pharmacological agents appear to be an effective approach. Sibutramine is a serotonin-noradrenaline reuptake inhibitor, which acts centrally by promoting the feeling of satiety and decreasing caloric intake, thus resulting in weight loss. A potential association with cardiovascular side effects has been noted. Orlistat, a gastric and pancreatic lipase inhibitor, also achieves significant weight loss and improves glycaemic status, but it has gastrointestinal side effects. Rimonabant, the first endocannabinoid CB1 antagonist, is associated with weight reduction and it improves diabetic parameters; nevertheless, it is associated with psychiatric disorders; indeed, a recently conducted safety review led to the temporal suspension of its commercialization. The above-mentioned medications seem to be currently useful agents for treating obesity in patients with type 2 diabetes mellitus. Other medications used for diabetes management, such as exenatide, liraglutide and pramlintide, have also shown body weight reduction. Ongoing research is needed to scrutinize the precise impact of these agents in the daily clinical practice of management of obesity in patients with type 2 diabetes mellitus.

Orlistat 120 mg improves glycaemic control in type 2 diabetic patients with or without concurrent weight loss

BACKGROUND

Both obesity and type 2 diabetes are associated with increased morbidity and mortality. Published data suggest that orlistat 120 mg, a lipase inhibitor used to treat obesity, may improve glycaemic parameters through weight loss-independent effects.

AIM

To investigate the effect of orlistat 120 mg on weight loss, and assess whether changes in glycaemic parameters [fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c)] are independent of weight loss.

METHODS

This retrospective analysis of pooled data from seven multicentre, double-blind, placebo-controlled studies involved overweight or obese patients with type 2 diabetes (aged 18-70 years). Patients were required to have a body mass index of 27-43 kg/m2, HbA1c of 6.5 to <13%, and stable weight for > or =3 months. Subjects received orlistat 120 mg tid or placebo for 6 or 12 months.

RESULTS

A total of 2550 overweight or obese patients with type 2 diabetes were enrolled and randomized to treatment with orlistat 120 mg tid (n = 1279) or placebo (n = 1271). For the whole population, patients treated with orlistat 120 mg had significantly greater mean decreases in FPG compared with placebo-treated patients (-1.39 mmol/l vs. -0.47 mmol/l; p < 0.0001). In addition, orlistat 120 mg provided significantly larger mean decreases in HbA1c compared with placebo (-0.74% vs. -0.31%; p < 0.0001). For patients with minimal weight loss (< or =1% of baseline body weight), orlistat 120 mg still provided a significantly greater decrease in the least squares mean value for both FPG (-0.83 mmol/l vs. +/-0.02 mmol/l; p = 0.0052) and HbA1c -0.29% vs. +/-0.14%; p = 0.0008). This suggested that the improvement of glycaemic control with orlistat 120 mg was independent of weight loss. Using linear regression analysis, improvement in glycaemic control (FPG and HbA1c) with orlistat 120 mg was less strongly correlated with weight loss than for placebo.

CONCLUSION

Orlistat 120 mg appears to improve glycaemic control more than would be predicted by weight loss alone in overweight or obese patients with type 2 diabetes. Postulated mechanisms underlying this effect include an improvement of insulin sensitivity, a slower and incomplete digestion of dietary fat, reduction of postprandial plasma non-esterified fatty acids, decreased visceral adipose tissue, and stimulation of glucagon-like peptide-1 secretion in the lower small intestine.

Orlistat in the prevention of diabetes in the obese patient

There has been an increase in the concern about preventing type 2 diabetes mellitus (T2DM), a disease with great and increasing prevalence. The prevalence of obesity, physical inactivity, Western processed diet, important risk factors for the development of T2DM, are also rising. Free fatty acids are increased in obesity and reduce insulin clearance and increase hepatic glucose production. Implementation of a healthy lifestyle has been show to slow the progression of impaired glucose tolerance to T2DM. Orlistat is an inhibitor of lipase activity, with proved efficacy in body weight reduction and long-term management of obesity and more favorable effects on carbohydrate metabolism and it was prospectively shown in XENDOS study that orlistat promoted long-term weight loss and prevented T2DM onset in obese individuals with normal and impaired glucose tolerance at baseline over four years. This benefit could be associated to the weight loss itself, to the limited absorption of lipids and reduction of plasma free fatty acids, to increased production of incretins or to modulation of secretion of cytokines by adipocytes, all effects secondary to orlistat treatment. A proposed strategy is to identify subjects at highest risk to receive a drug intervention, using lifestyle interventions alone at the community level.

Short-term administration of orlistat reduced daytime triglyceridemia in obese women with the metabolic syndrome

The objective of this prospective, controlled, randomized study was to evaluate the effect of orlistat administration for 10 days on daytime capillary triglyceridemia in obese women with metabolic syndrome (MetSyn). Thirty-two obese, nondiabetic women with MetSyn were evaluated. The presence of MetSyn was defined according to the National Cholesterol Education Program (NCEP)-Adult Treatment Panel III (ATP III) criteria. Patients were randomized into 2 similar groups: group A (orlistat), mean age 50.1 -/+ 8.2 years, received a low-calorie diet combined with orlistat 120 mg tid for 10 days and group B (control), mean age 51.2 -/+ 9.1 years, received only the low-calorie diet for the same period of time. Anthropometric, lipids, and parameters of insulin resistance were measured before and after 10 days of intervention. Capillary triglycerides (TGc) were measured at 6 different time points during the day and daytime triglyceridemia was expressed as area under the curve of TGc (AUC-TGc). Most anthropometric measurements (body weight, body mass index, waist circumference, and percentage of fat mass) and most metabolic parameters (total cholesterol [TC], fasting venous triglycerides [TGfv], high-density lipoprotein cholesterol [HDL-C] levels, fasting glucose [FG], fasting insulin [FI], and homeostasis model for assessment [HOMA] for insulin resistance index) decreased significantly in both groups, while waist-to-hip ratio (WHR) and systolic (SBP) and diastolic blood pressure (DBP) did not change significantly in both groups and low-density lipoprotein cholesterol (LDL-C) levels decreased only in the orlistat group. Following minimal weight loss, TGc at most time points and AUC-TGc were significantly reduced only in group A. In group A, AUG-TGc decreased by 17% from 36.4 -/+11.8 to 30.2 -/+9.9 mmol/Lxh(-1) (p < 0.001), and this reduction was significantly greater compared with the control group (p < 0.05) and remained significant after percentage of weight loss was taken into account. This decrease of AUC-TGc significantly correlated with the decrease of HOMA index (p < 0.05, r = 0.39) and the decrease of TGfv (p < 0.001, r = 0.62). The tolerability of orlistat was very good and side effects were transient and of minimal intensity. In conclusion, short-term administration of orlistat significantly reduced daytime triglyceridemia in obese, nondiabetic women with MetSyn. This reduction could offer cardiovascular benefits in these high-risk patients. Long-term studies with more patients are needed to reach definite conclusions.

The use of orlistat in the treatment of obesity, dyslipidaemia and Type 2 diabetes

Orlistat (tetrahydrolipstatin) is an inhibitor of gastrointestinal lipases, especially pancreatic lipase. It is used as an adjunct to diet and exercise in order to achieve weight loss in obese individuals (body mass index > 30 kg/m2) or in overweight individuals (body mass index > 27 kg/m2) with other risk factors for atherosclerotic vascular disease, such as hypertension, dyslipidaemia or diabetes. Short- and long-term studies of up to 4 years duration have shown the drug to have significant benefits in weight loss, as well as in the reduction in lipids, glucose and haemoglobin A1c, and in time to onset of Type 2 diabetes compared with diet alone or placebo groups. The incremental amount of weight loss that orlistat produces is modest, but sufficient to result in improvement in obesity comorbidities such as elevated blood pressure, dyslipidaemia and hyperglycaemia compared with diet and exercise alone. Orlistat should only be prescribed for individuals who are motivated to adhere to lifestyle modifications, especially dietary fat restriction.

Adiposopathy is a more rational treatment target for metabolic disease than obesity alone

Current guidelines recommend that weight-loss therapy should be primarily based upon specific body mass index (BMI) cut-off limits. However, in the adipocentric paradigm, it is acknowledged that co-morbidities, such as type 2 diabetes mellitus, hypertension, and dyslipidemia, occur at all levels of BMI. Excessive fat mass (adiposity) in genetically susceptible individuals results in fat dysfunction (adiposopathy), which then contributes to metabolic disorders that increase the risk of atherosclerotic cardiovascular disease. In this paradigm, the term "anti-obesity" treatment might best be replaced by "anti-adiposopathy" treatment, wherein the focus is not based solely on BMI, but instead directed towards physiologically improving fat cell function and clinically improving the metabolic health of patients. This may occur through appropriate diet, physical exercise, and other lifestyle changes, and/or from drug therapies. Cannabinoid receptor antagonists and peroxisome proliferator activated receptor agonists are examples of agents that physiologically improve fat function and clinically improve metabolic disease.

A randomized study of orlistat in combination with a weight management programme in obese patients with Type 2 diabetes treated with metformin

AIMS

To assess the effects of orlistat vs. placebo, in combination with a weight management programme, on weight loss and metabolic control in obese patients with Type 2 diabetes.

METHODS

Patients treated with either metformin alone or metformin in combination with sulphonylurea were randomized to double-blind treatment with orlistat or placebo (120 mg) three times daily, combined with a mildly reduced calorie diet and a weight management programme for 52 weeks. Changes in body weight, anthropometry, glycaemic control and lipid profile were assessed.

RESULTS

After 52 weeks, orlistat-treated patients achieved an almost threefold greater reduction in weight compared with placebo recipients (-5.0% vs. -1.8%; P<0.0001). The decrease in waist circumference was significantly greater with orlistat than placebo (-4.8 cm vs. -2.8 cm; P=0.0022). Orlistat treatment was also associated with significantly greater reductions in haemoglobin A(1c) (-1.1% vs. -0.2%; P<0.0001), fasting plasma glucose (-1.9 mmol/l vs. -0.3 mmol/l; P<0.0001), total cholesterol (-0.2 mmol/l vs. 0.1 mmol/l; P=0.03) and apolipoprotein B (-0.08 g/l vs. 0.01 g/l; P=0.0085) and greater improvements in beta-cell function (P=0.031) and insulin resistance (P=0.001) assessed using the homeostasis model assessment (HOMA). Similar results were obtained for subgroups of patients treated with metformin alone or metformin in combination with sulphonylurea. Orlistat treatment reduced the requirement for anti-diabetic medication more than placebo.

CONCLUSIONS

Orlistat, in combination with a reduced calorie diet and a weight management programme, promotes weight loss and clinically relevant improvements in glycaemic control and other cardiovascular risk factors in obese patients with Type 2 diabetes.

The effects of orlistat on metabolic parameters and other cardiovascular risk factors

Orlistat is an antiobesity drug with a well documented efficacy in weight reduction and weight maintenance. Weight reduction with orlistat has been associated with a favourable effect on obesity-related cardiovascular risk factors. Orlistat treatment is associated with a reduction in serum insulin levels. Moreover, orlistat reduces the incidence of type 2 diabetes in patients with impaired glucose tolerance and lowers the required dose of metformin, sulfonylureas and insulin in patients with type 2 diabetes. Furthermore, orlistat can reduce total and low density lipoprotein (LDL) cholesterol levels and improve postprandial triglyceridemia, as well as the low density lipoprotein cholesterol/high density lipoprotein cholesterol ratio (LDL/HDL ratio). Moreover, orlistat appears to have a favourable effect on some inflammatory markers, such as TNF-alpha and interleukin-6 and has a time-depended effect on some haemostatic factors.

Orlistat: a review of its use in the management of patients with obesity

Orlistat is an inhibitor of gastrointestinal lipases and, therefore, prevents the absorption of dietary fat. This agent reduces weight in obese adults and adolescents with or without comorbidities (including type 2 diabetes mellitus, hypercholesterolaemia, hypertension, metabolic syndrome) who received up to 4 years of therapy in conjunction with a hypocaloric diet. In obese patients, orlistat in combination with a hypocaloric diet improved metabolic risk factors and reduced the risk of developing type 2 diabetes. Furthermore, this agent was cost effective in patients with obesity, particularly those with type 2 diabetes. Orlistat is generally well tolerated, with gastrointestinal adverse events being most commonly reported. Orlistat, in addition to lifestyle and dietary intervention, is thus an attractive option for the treatment of patients with obesity, especially those with associated comorbidities or at risk of developing type 2 diabetes.

Determinants of postprandial triglyceride and remnant-like lipoproteins in type 2 diabetes

BACKGROUND

Postprandial changes in remnant-like lipoprotein particles (RLP) contribute to the severity of coronary heart disease in type 2 diabetes. Since the determinants of postprandial response in RLP are not well understood, this study investigated the roles of fasting triglyceride, apolipoprotein (apo) E polymorphism and insulin resistance in a group of overweight/obese Chinese type 2 diabetic subjects.

METHODS

Postprandial triglyceride (TG) and RLP-cholesterol (RLP-C) were determined after a mixed meal containing 70-g fat at 2-h intervals for 8 h in 32 normotriglyceridemic (NTG) and 31 hypertriglyceridemic (HTG) subjects. RLP-C was measured using an immunoseparation assay and apo E genotypes using polymerase chain reaction and restriction mapping. Insulin resistance was defined as homeostasis model assessment index (HOMA-IR).

RESULTS

The HTG subjects had greater postprandial increase in TG and RLP-C than NTG (p < 0.001), but there were no significant differences in HOMA-IR and apo E allele frequencies. Subjects who were non-E3-carriers had the largest postprandial increment in TG and RLP-C. On stepwise linear regression analysis, log(HOMA-IR) was only an independent determinant of fasting TG but not postprandial TG or RLP-C. The major determinants of fasting and postprandial RLP-C were fasting TG and apo E genotype, accounting for 53 and 6% of the variance of fasting RLP-C (p < 0.01) and 31 and 13% of the variance of postprandial RLP-C respectively (p < 0.01).

CONCLUSIONS

Insulin resistance is mainly a determinant of fasting triglyceride in Chinese type 2 diabetic subjects, whereas apo E genotype is a better predictor of both fasting and postprandial concentrations of RLP.

Pharmacotherapy for weight loss in adults with type 2 diabetes mellitus

BACKGROUND

Obesity is closely related to type 2 diabetes and long-term weight reduction is an important part of the care delivered to obese persons with diabetes.

OBJECTIVES

To assess the efficacy of pharmacotherapy for weight loss in adults with type 2 diabetes.

SEARCH STRATEGY

Computerized searches were performed of MEDLINE (January 1966 to May 2004), EMBASE (January 1974 to May 2004, Web of Science (January 1981 to May 2004, and other electronic bibliographic databases, supplemented with hand searches of reference lists and selected journals.

SELECTION CRITERIA

Randomized, controlled trials were included where pharmacotherapy was used as the primary strategy for weight loss among adults with type 2 diabetes. Published and unpublished literature in any language and with any study design was included.

DATA COLLECTION AND ANALYSIS

Two reviewers abstracted data and the quality of included studies was evaluated by assessing potential attrition, as well as selection and measurement bias, and a Jadad score was obtained. Effects were combined using a random effects model.

MAIN RESULTS

A sufficient number of studies were available for a quantitative synthesis for fluoxetine, orlistat, and sibutramine. Twenty two randomized controlled trials were included in the review, with a total of 296 participants for fluoxitine, 2036 for orlistat, and 1047 for sibutramine. Pharmacotherapy produced modest reductions in weight for fluoxetine (5.1 kg (95% confidence interval [CI], 3.3 - 6.9) at 24 to 26 weeks follow up; orlistat 2.0 kg (CI, 1.3 - 2.8) at 12 to 57 weeks follow-up, and sibutramine 5.1 kg (CI, 3.2 - 7.0) at 12 to 52 weeks follow-up. Glycated hemoglobin also modestly and significantly reduced for fluoxetine and orlistat. Gastrointestinal side effects were common with orlistat; tremor, somnolence and sweating with fluoxetine; and palpitations with sibutramine. Some studies, using a variety of study designs, were available on other drugs and a significant decrease in weight was noted in three studies of mazindol, one of phenmetrazine, two of phentermine. No studies were identified that fit inclusion criteria for pseudophedrine, ephedra, sertraline, yohimbine, amphetamine or its derivatives, bupropion, topiramate, benzocaine, threachlorocitric acid, sertraline, and bromocriptine.

AUTHORS' CONCLUSIONS

Fluoxetine, orlistat, and sibutramine can achieve statistically significant weight loss over 12 to 57 weeks. The magnitude of weight loss is modest, however, and the long-term health benefits remain unclear. The safety of sibutramine is uncertain. There is a paucity of data on other drugs for weight loss or control in persons with type 2 diabetes.

The effects of rosiglitazone on fatty acid and triglyceride metabolism in type 2 diabetes

AIMS/HYPOTHESIS

We investigated the effects of rosiglitazone on NEFA and triglyceride metabolism in type 2 diabetes.

METHODS

In a double-blind, placebo-controlled, cross-over study of rosiglitazone in diet-treated type 2 diabetic subjects, we measured arteriovenous differences and tissue blood flow in forearm muscle and subcutaneous abdominal adipose tissue, used stable isotope techniques, and analysed gene expression. Responses to a mixed meal containing [1,1,1-(13)C]tripalmitin were assessed.

RESULTS

Rosiglitazone induced insulin sensitisation without altering fasting NEFA concentrations (-6.6%, p=0.16). Postprandial NEFA concentrations were lowered by rosiglitazone compared with placebo (-21%, p=0.04). Adipose tissue NEFA release was not decreased in the fasting state by rosiglitazone treatment (+24%, p=0.17) and was associated with an increased fasting hormone-sensitive lipase rate of action (+118%, p=0.01). Postprandial triglyceride concentrations were decreased by rosiglitazone treatment (-26%, p<0.01) despite unchanged fasting concentrations. Rosiglitazone did not change concentrations of triglyceride-rich lipoprotein remnants. Adipose tissue blood flow increased with rosiglitazone (+32%, p=0.03). Postprandial triglyceride [(13)C]palmitic acid concentrations were unchanged, whilst NEFA [(13)C]palmitic acid concentrations were decreased (p=0.04). In muscle, hexokinase II mRNA expression was increased by rosiglitazone (+166%, p=0.001) whilst the expression of genes involved in insulin signalling was unchanged. Adipose tissue expression of FABP4, LPL and FAT/CD36 was increased.

CONCLUSIONS/INTERPRETATION

Rosiglitazone decreases postprandial NEFA and triglyceride concentrations. This may represent decreased spillover of NEFAs from adipose tissue depots. Decreased delivery of NEFAs to the liver may lead to lowered postprandial triglyceride concentrations. Upregulation of hexokinase II expression in muscle may contribute to insulin sensitisation by rosiglitazone.

Orlistat augments postprandial increases in glucagon-like peptide 1 in obese type 2 diabetic patients

OBJECTIVE

Orlistat leads to improved glycemic control in obese type 2 diabetic patients, which is attributed to decreased insulin resistance associated with weight loss. Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are gut hormones that are secreted in response to food intake, and they both stimulate insulin secretion. Orlistat decreases fat absorption and increases intestinal fat content, which may lead to increased secretion of these peptides. In this pilot study, we tested the hypothesis that increased levels of these intestinal hormones may be involved in the improvement of postprandial hyperglycemia observed previously with orlistat in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

A total of 29 type 2 diabetic patients, who were not taking insulin or alpha-glucosidase inhibitors, were enrolled in the study. On a crossover and single-blind design, after an overnight fasting, the patients received 120-mg orlistat or placebo capsules, followed by a standard 600-kcal mixed meal that contained 38% fat. At baseline and 60 min after the meal, blood samples were obtained for the measurement of GLP-1, GIP, insulin, C-peptide, triglycerides, free fatty acids, and glucose.

RESULTS

All measured parameters increased significantly in response to the mixed meal compared with baseline, both with orlistat or placebo. When compared with the placebo, the orlistat administration resulted in a significantly enhanced postprandial increase in GLP-1 and C-peptide levels and attenuated the postprandial rise in glucose and triglycerides.

CONCLUSIONS

The results of this study suggest that apart from decreasing insulin resistance as a result of weight loss, orlistat may increase postprandial GLP-1 levels, thereby enhancing the insulin secretory response to the meal and blunting the postprandial rise in glucose in type 2 diabetic patients. Increased GLP-1 levels, which lead to decreased food intake, may also contribute to the weight loss that is associated with the use of this drug.

Effects of moderate weight loss and orlistat on insulin resistance, regional adiposity, and fatty acids in type 2 diabetes

OBJECTIVE

Moderate weight loss is recommended for overweight and obese patients with type 2 diabetes, and conjunctive use of weight loss medication has been advocated. The current study examined weight loss-dependent and -independent effects of the intestinal lipase inhibitor orlistat at 6 months of treatment, using behavioral intervention (Int) combined with randomized, double-blinded, placebo (P)-controlled treatment with orlistat (O).

RESEARCH DESIGN AND METHODS

Metabolic control, insulin sensitivity (IS), regional fat distribution, and fat content in liver and muscle were measured in 39 volunteers with type 2 diabetes in whom all antidiabetic medication was withdrawn 1 month preceding randomization. Weight loss was equivalent in the Int+O and Int+P groups, respectively (-10.3 +/- 1.3 vs. -8.9 +/- 1.1%), and there were identical decreases in visceral adipose tissue (VAT), fat mass (FM), thigh adiposity, and hepatic steatosis.

RESULTS

Weight loss resulted in substantial improvement (P < 0.001) in HbA(1c) (-1.6 +/- 0.3 vs. -1.0 +/- 0.4%; NS between groups). IS improved significantly more with orlistat (Delta2.2 +/- 0.4 vs. Delta1.2 +/- 0.4 mg. min(-1). kg(-1) fat-free mass [FFM]; P < 0.05), and plasma free fatty acid (FFA) levels were strongly correlated with IS (r = 0.56; P < 0.001). Orlistat caused greater reductions in fasting plasma FFA (Delta-154 +/- 22 vs. Delta-51 +/- 33 micro mol/l; P < 0.05), insulin-suppressed FFA (Delta-119 +/- 23 vs. Delta-87 +/- 34 micro mol/l; P < 0.05), and fasting plasma glucose (FPG; -62 +/- 9 vs. -32 +/- 8 mg/dl; P = 0.02). Changes in HbA(1c) were correlated with DeltaIS (r = -0.41; P < 0.01) but not with weight loss per se.

CONCLUSIONS

At equivalent weight loss, conjunctive use of orlistat resulted in greater improvement in FFA levels and IS.