Effects of equal weight loss with orlistat and placebo on body fat and serum fatty acid composition and insulin resistance in obese women

A systematic review, ANCOVA meta-analysis, and meta-regression of clinical trials: Orlistat and body mass index of overweight and obese patients

Background:

Obesity or overfat (i.e., excessive fat accumulation in the host) contributes to cerebrocardiovascular and other diseases. Orlistat is a good obesity medication, unlike other drugs that have higher cardiac toxicity. It reversibly inhibits pancreatic and gastric lipases, and improves oxysterol metabolism. This study summarizes and elaborates the impact of orlistat on BMI in overweight and obese adult patients.

Methods:

All authors systematically searched and retrieved 288 controlled trial articles on orlistat and BMI from three databases, two registries, and citation searches using specific keywords. The quality and bias risks were determined by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), Risk of Bias in Non-Randomized Study (ROBINS-I), and modified Jadad scale. R version 4.2.2 software calculated the effect size and the analysis of covariance (ANCOVA) effect, and subsequently analyzed using metafor.

Results:

This novel meta-analysis included 114 studies with 24,600 overweight or obese participants. We showed that orlistat substantially reduced BMI (mean difference −0.78 [−0.94, −0.63], p < 0.0001; I2 = 90.19%, pheterogeneity < 0.0001). Similarly, meta-regression showed a significant impact of orlistat daily dose (ß = −0.0019), yet not for duration (ß = −0.0024) and location (ß = −0.8591, −0.0190).

Conclusion:

Orlistat has the capacity to reduce BMI in overweight and obese individuals. Medical practitioners shall prescribe orlistat as a BMI lowering agent to complement other intervention in those patients

Do anti-obesity medical treatments have a direct effect on adipose tissue?

During the past years, several drugs have been developed for the treatment of obesity. Some are already used in clinical practice: orlistat, GLP-1 receptor agonists (RA), GLP-1/GIP biagonists and the melanocortin 4 receptor (MC4R) agonist, setmelanotide. Some should be available in the future: GLP-1/glucagon biagonists, GLP-1/GIP/glucagon triagonists. These drugs act mainly by reducing food intake or fat absorption. However, many of them show specific effects on the adipose tissue. All these drugs show significant reduction of fat mass and, more particularly of visceral fat. If most of the drugs, except orlistat, have been shown to increase energy expenditure in rodents with enhanced thermogenesis, this has not yet been clearly demonstrated in humans. However, biagonists or triagonist stimulating glucagon seem to a have a more potent effect to increase thermogenesis in the adipose tissue and, thus, energy expenditure. Most of these drugs have been shown to increase the production of adiponectin and to reduce the production of pro-inflammatory cytokines by the adipose tissue. GLP-1RAs reduce the size of adipocytes and promote their differentiation. GLP-1RAS and GLP-1/GIP biagonists reduce, in the adipose tissue, the expression of several genes involved in lipogenesis. Further studies are still needed to clarify the precise roles, on the adipose tissue, of these drugs dedicated for the treatment of obesity.

Insulin resistance is associated with high-risk coronary artery plaque composition in asymptomatic men between 65 and 75 years and no diabetes: A DANCAVAS cross-sectional sub-study

BACKGROUND AND AIMS

Insulin resistance (IR) and pre-diabetes are associated with an increased risk of cardiovascular disease (CVD). We aimed to investigate vulnerable plaque composition in relation to IR and pre-diabetes in asymptomatic non-diabetic men.

METHODS

All participants underwent a contrast-enhanced coronary computed tomography angiography (CCTA) to evaluate coronary artery plaque burden and plaque composition (necrotic core, dense calcium, fibrotic and fibrous-fatty volume). Homeostasis model assessment of IR (HOMA-IR) was used, and participants were stratified into tertiles. Participants underwent a standard oral glucose tolerance test (OGTT) and were categorized into 2 groups (normal glucose tolerance (NGT) or pre-diabetes). A multivariable linear regression model was used to evaluate the association between vulnerable plaque composition and IR or glycemic group.

RESULTS

Four-hundred-and-fifty non-diabetic men without known CAD were included. The mean age was 70 ± 3 years. Participants in the higher HOMA-IR tertile (H-IR) had higher median necrotic plaque volume compared to the lower HOMA-IR tertile (L-IR) (18.2 vs. 11.0 mm3, p = 0.02). H-IR tertile (β 0.37 [95% CI 0.10-0.65], p = 0.008), pack-years (β 0.07 [95% CI 0.007-0.14], p = 0.03) and total atheroma volume (TAV) (β 0.47 [95% CI 0.36-0.57], p < 0.001) remained associated with necrotic plaque volume in the multivariable linear regression model.

CONCLUSIONS

IR was associated with necrotic plaque volume in asymptomatic men without diabetes. Thus, even in asymptomatic men without diabetes, IR seems to have an incremental effect on necrotic plaque volume and vulnerable plaque composition.

Effect of Orlistat on anthropometrics and metabolic indices in children and adolescents: a systematic review and meta-analysis

BACKGROUND

Childhood obesity is one of the main concerns of public health. Considering its long-term adverse health effect, various studies investigated the effect of drug therapy on anthropometric parameters and provided mixed results. In this systematic review and meta-analysis, we aimed to determine the effect of Orlistat on anthropometrics and biochemical parameters in children and adolescents.

MATERIALS AND METHODS

The databases of PubMed, Scopus, and Web of Science were searched until September 2022. Experimental and semi-experimental studies were included if they evaluated the effect of Orlistat on obesity-related parameters in children and reported the before and after anthropometric values. A revised Cochrane risk-of-bias (Rob2) was used to evaluate the methodological quality. STATA software version 16.0 was used for the meta-analysis of the random-effect model.

RESULTS

Of 810 articles retrieved in the initial search, four experimental and two semi-experimental studies were selected for systematic review. The result of the meta-analysis of experimental studies indicated the significant effect of Orlistat on waist circumference (SMD: -0.27, 95% CI: -0.47, -0.07) and serum insulin level (SMD: -0.89, 95% CI: -1.52, 0.26). However, there were no significant effects of orlistat on body weight, body mass index, lipid profile, and serum glucose level.

CONCLUSION

The present meta-analysis showed the significant effect of Orlistat on the reduction of waist circumference and insulin level in overweight and obese adolescents. However, due to the paucity of studies included in the meta-analysis, more prospective studies with longer duration and more sample sizes will be needed in this age group.

Comparing and contrasting different herbal products intended for the management of obesity approved in the Palestinian markets

BACKGROUND

The use of conventional medical therapies has proven to have many setbacks and safety concerns that need further improvement. However, herbal medicine has been used for over 2000 years, and many studies have proven the use of herbs to be effective and safe. This article discussed the efficacy of different herbal products used in the management of obesity. To evaluate the efficacy of seven herbal-based weight loss products currently available on the Palestinian market, using in vitro assays to screen for antioxidants, anti-amylase, and anti-lipase effects for each product.

METHOD

Pancreatic lipase and salivary amylase inhibitory activities, as well as antioxidant analysis, were tested in vitro on a variety of herbal products. Then the IC₅₀ was measured for each test.

RESULTS

The anti-lipase assay results, IC₅₀ values in (μg/mL) of each of the seven products (Product A, product B, product C, product D, product E, product F, and product G) were 114.78, 532.1, 60.18, 53.33, 244.9, 38.9, and 48.97, respectively. The IC₅₀ value for orlistat (Reference) was 12.3 μg/ml. On the other hand, the IC₅₀ value for alpha amylase inhibition of the seven products (Product A, product B, product C, product D, product E, product F, and product F) were 345.93, 13,803.84 (Inactive), 73.79, 130.91, 165.95, 28.18, and 33.11 μg/ml respectively, while acarbose (Reference) was 23.38 μg/ml. The antioxidant activity (IC₅₀ values) for the seven products (Product A, product B, product C, product D, product E, product F, and product F) were 1258.92, 707.94, 79.43, 186.20, 164.81, 17.53, and 10.47 μg/ml respectively. While the IC₅₀ value for Trolox was 2.70 μg/ml.

CONCLUSION

It can be concluded that the seven products showed varied anti-lipase, anti-amylase, and antioxidant effects. However, products F and G showed superiority in all categories.

Reversal and Remission of T2DM - An Update for Practitioners

Over the past 50 years, many countries around the world have faced an unchecked pandemic of obesity and type 2 diabetes (T2DM). As best practice treatment of T2DM has done very little to check its growth, the pandemic of diabesity now threatens to make health-care systems economically more difficult for governments and individuals to manage within their budgets. The conventional view has been that T2DM is irreversible and progressive. However, in 2016, the World Health Organization (WHO) global report on diabetes added for the first time a section on diabetes reversal and acknowledged that it could be achieved through a number of therapeutic approaches. Many studies indicate that diabetes reversal, and possibly even long-term remission, is achievable, belying the conventional view. However, T2DM reversal is not yet a standardized area of practice and some questions remain about long-term outcomes. Diabetes reversal through diet is not articulated or discussed as a first-line target (or even goal) of treatment by any internationally recognized guidelines, which are mostly silent on the topic beyond encouraging lifestyle interventions in general. This review paper examines all the sustainable, practical, and scalable approaches to T2DM reversal, highlighting the evidence base, and serves as an interim update for practitioners looking to fill the practical knowledge gap on this topic in conventional diabetes guidelines.

Long-term effects of weight-reducing drugs in people with hypertension

BACKGROUND

This is the third update of this review, first published in July 2009. All major guidelines on treatment of hypertension recommend weight loss; anti-obesity drugs may be able to help in this respect.

OBJECTIVES

Primary objectives: To assess the long-term effects of pharmacologically-induced reduction in body weight in adults with essential hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events).. Secondary objectives: To assess the long-term effects of pharmacologically-induced reduction in body weight in adults with essential hypertension on change from baseline in systolic and diastolic blood pressure, and on body weight reduction.

SEARCH METHODS

For this updated review, the Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to March 2020: the Cochrane Hypertension Specialised Register, CENTRAL, MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. The searches had no language restrictions. We contacted authors of relevant papers about further published and unpublished work.

SELECTION CRITERIA

Randomised controlled trials of at least 24 weeks' duration in adults with hypertension that compared approved long-term weight-loss medications to placebo.  DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, assessed risks of bias, and extracted data. Where appropriate and in the absence of significant heterogeneity between studies (P > 0.1), we pooled studies using a fixed-effect meta-analysis. When heterogeneity was present, we used the random-effects method and investigated the cause of the heterogeneity.

MAIN RESULTS

This third update of the review added one new trial, investigating the combination of naltrexone/bupropion versus placebo. Two medications, which were included in the previous versions of this review (rimonabant and sibutramine) are no longer considered relevant for this update, since their marketing approval was withdrawn in 2010 and 2009, respectively. The number of included studies in this review update is therefore six (12,724 participants in total): four RCTs comparing orlistat to placebo, involving a total of 3132 participants with high blood pressure and a mean age of 46 to 55 years; one trial comparing phentermine/topiramate to placebo, involving 1305 participants with high blood pressure and a mean age of 53 years; and one trial comparing naltrexone/bupropion to placebo, involving 8283 participants with hypertension and a mean age of 62 years. We judged the risks of bias to be unclear for the trials investigating orlistat or naltrexone/bupropion. and low for the trial investigating phentermine/topiramate. Only the study of naltrexone/bupropion included cardiovascular mortality and morbidity as predefined outcomes. There were no differences in the rates of all-cause or cardiovascular mortality, major cardiovascular events, or serious adverse events between naltrexone/bupropion and placebo. The incidence of overall adverse events was significantly higher in participants treated with naltrexone/bupropion. For orlistat, the incidence of gastrointestinal side effects was consistently higher compared to placebo. The most frequent side effects with phentermine/topiramate were dry mouth and paraesthesia. After six to 12 months, orlistat reduced systolic blood pressure compared to placebo by mean difference (MD) -2.6 mm Hg (95% confidence interval (CI) -3.8 to -1.4 mm Hg; 4 trials, 2058 participants) and diastolic blood pressure by MD -2.0 mm Hg (95% CI -2.7 to -1.2 mm Hg; 4 trials, 2058 participants). After 13 months of follow-up, phentermine/topiramate decreased systolic blood pressure compared to placebo by -2.0 to -4.2 mm Hg (1 trial, 1030 participants) (depending on drug dosage), and diastolic blood pressure by -1.3 to -1.9 mm Hg (1 trial, 1030 participants) (depending on drug dosage). There was no difference in the change in systolic or diastolic blood pressure between naltrexone/bupropion and placebo (1 trial, 8283 participants). We identified no relevant studies investigating liraglutide or lorcaserin in people with hypertension.

AUTHORS' CONCLUSIONS

In people with elevated blood pressure, orlistat, phentermine/topiramate and naltrexone/bupropion reduced body weight; the magnitude of the effect was greatest with phentermine/topiramate. In the same trials, orlistat and phentermine/topiramate, but not naltrexone/bupropion, reduced blood pressure. One RCT of naltrexone/bupropion versus placebo showed no differences in all-cause mortality or cardiovascular mortality or morbidity after two years. The European Medicines Agency refused marketing authorisation for phentermine/topiramate due to safety concerns, while for lorcaserin the application for European marketing authorisation was withdrawn due to a negative overall benefit/risk balance. In 2020 lorcaserin was also withdrawn from the US market. Two other medications (rimonabant and sibutramine) had already been withdrawn from the market in 2009 and 2010, respectively.

In vivo metabolic investigation of cetilistat in normal versus pseudo-germ-free rats using UPLC-QTOFMS/MS and in silico toxicological evaluation of its metabolites

Cetilistat (CET) is a pancreatic lipase inhibitor approved for management of obesity after the serious adverse effects exhibited by its analogue orlistat. Exhaustive literature review reveals lack of comprehensive reports on its biotransformation. With a view to study the same, the present study reports the identification and characterization of metabolites of CET in rats using UPLC-MS/MS. As the small intestine is the site of action for CET, it is important that the role of microbial flora in the metabolism of CET be explored. To achieve this, the metabolic profile of CET was compared between normal and pseudo-germ-free rats. The study involved the administration of a drug suspension to male Sprague-Dawley pseudo-germ-free and normal untreated rats followed by collection of urine, feces, and blood at specific intervals. Sample preparation was performed using liquid-liquid extraction and concentration of samples followed by analysis using LC-MS/MS. Finally, an in silico study was performed on the drug and metabolites to predict their toxicological properties using ADMET Predictor^TM software. Four metabolites of CET were observed in in vivo matrices. As expected, significant changes were observed both qualitatively and quantitatively, implying that formation of metabolites was both CYP enzymes and gut microflora mediated.

The effect of orlistat versus metformin on body composition and insulin resistance in obese premenopausal women: 3-month randomized prospective open-label study

INTRODUCTION

Our aim was to evaluate the effects of metformin and orlistat on body composition and glucose-insulin homeostasis in obese premenopausal women.

MATERIAL AND METHODS

Seventy-three obese premenopausal Caucasian women aged 32.4 ±8.3 years were treated with either metformin (1000 mg/day; n = 37) or orlistat (360 mg/day; n = 36). Anthropometric parameters were measured using dual-energy X-ray absorptiometry. Glucose tolerance, using the oral glucose tolerance test; insulin resistance, using the homeostasis model assessment (HOMA-IR); and insulin sensitivity, using the Matsuda insulin sensitivity index (ISI Matsuda), were assessed at the commencement of the study and after 3 months.

RESULTS

Those treated with orlistat showed greater weight loss (-9.4 ±2.3 vs. -4.9 ±1.3 kg, p < 0.05) and decrease of fat mass (-5.4 ±3.0 vs. -3.5 ±0.7 kg, p < 0.05) than those treated with metformin. The percentage of android and gynoid fat deposits was reduced in both groups; however, a greater decrease in android fat was observed in those treated with metformin. Improvement in ISI Matsuda and post-load insulin were similar in both groups. High initial post-load insulin and low ISI Matsuda corresponded with reductions in total fat, trunk fat, and waist circumference in both groups, and a decrease in android fat in those treated with metformin.

CONCLUSIONS

Orlistat treatment resulted in greater weight loss and improvement in body composition; metformin treatment resulted in a reduction of android fat. Both drugs produced a comparable improvement in insulin/glucose homeostasis. Overall, insulin-resistant women showed improvement with treatment, irrespective of which drug was used.

Long-term effects of weight-reducing drugs in people with hypertension

BACKGROUND

All major guidelines on antihypertensive therapy recommend weight loss; anti-obesity drugs may be able to help in this respect.

PRIMARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight in adults with essential hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events).

SECONDARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight in adults with essential hypertension on change from baseline in systolic blood pressure, change from baseline in diastolic blood pressure, and body weight reduction.

SEARCH METHODS

We obtained studies using computerised searches of the Cochrane Hypertension Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid EMBASE, the clinical trials registry ClinicalTrials.gov, and from handsearches in reference lists and systematic reviews (status as of 13 April 2015).

SELECTION CRITERIA

Randomised controlled trials in hypertensive adults of at least 24 weeks' duration that compared long-term pharmacologic interventions for weight loss with placebo. 

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, and extracted data. Where appropriate and in the absence of significant heterogeneity between studies (P > 0.1), we pooled studies using fixed-effect meta-analysis. When heterogeneity was present, we used the random-effects method and investigated the cause of heterogeneity.

MAIN RESULTS

After updating the literature search, which was extended to include four new weight-reducing drugs, we identified one additional study of phentermine/topiramate, bringing the total number of studies to nine that compare orlistat, sibutramine, or phentermine/topiramate to placebo and thus fulfil our inclusion criteria. We identified no relevant studies investigating rimonabant, liraglutide, lorcaserin, or naltrexone/bupropion. No study included mortality and cardiovascular morbidity as predefined outcomes. Incidence of gastrointestinal side effects was consistently higher in those participants treated with orlistat versus those treated with placebo. The most frequent side effects were dry mouth, constipation, and headache with sibutramine, and dry mouth and paresthaesia with phentermine/topiramate. In participants assigned to orlistat, sibutramine, or phentermine/topiramate body weight was reduced more effectively than in participants in the usual-care/placebo groups. Orlistat reduced systolic blood pressure as compared to placebo by -2.5 mm Hg (mean difference (MD); 95% confidence interval (CI): -4.0 to -0.9 mm Hg) and diastolic blood pressure by -1.9 mm Hg (MD; 95% CI: -3.0 to -0.9 mm Hg). Sibutramine increased diastolic blood pressure compared to placebo by +3.2 mm Hg (MD; 95% CI: +1.4 to +4.9 mm Hg). The one trial that investigated phentermine/topiramate suggested it lowered blood pressure.

AUTHORS' CONCLUSIONS

In people with elevated blood pressure, orlistat and sibutramine reduced body weight to a similar degree, while phentermine/topiramate reduced body weight to a greater extent. In the same trials, orlistat and phentermine/topiramate reduced blood pressure, while sibutramine increased it. We could include no trials investigating rimonabant, liraglutide, lorcaserin, or naltrexone/bupropion in people with elevated blood pressure. Long-term trials assessing the effect of orlistat, liraglutide, lorcaserin, phentermine/topiramate, or naltrexone/bupropion on mortality and morbidity are unavailable and needed. Rimonabant and sibutramine have been withdrawn from the market, after long-term trials on mortality and morbidity have confirmed concerns about the potential severe side effects of these two drugs. The European Medicines Agency refused marketing authorisation for phentermine/topiramate due to safety concerns, while the application for European marketing authorisation for lorcaserin was withdrawn by the manufacturer after the Committee for Medicinal Products for Human Use judged the overall benefit/risk balance to be negative.

Superstition predicts favorable weight change in an open-placebo trial: a prospective study

Given the difficulty of losing weight via adhering to healthy lifestyle choices, this study sought to understand how a placebo may elicit favorable weight change. Specifically, we examined if superstition may be related to increased responsiveness to an open-placebo. In this pilot study of 25 undergraduate participants, it was hypothesized that individuals with higher levels of superstition may be more responsive to a 3-week open-placebo weight change trial. Participants were given once-daily saltine crackers to use as open-placebos for weight change in their preferred direction (gain or loss). The weight of each participant was measured before and after the 3-week open-placebo period. A Pearson's r correlation showed a significant positive relationship between superstition and placebo responsiveness, determined by weight gain or loss in the preferred direction, r (25) = 0.493, p < 0.05. We hope these preliminary results engender future research on open-placebo uses for weight management.

Obesity induced rapid melanoma progression is reversed by orlistat treatment and dietary intervention: role of adipokines

Obesity, owing to adiposity, is associated with increased risk and development of various cancers, and linked to their rapid growth as well as progression. Although a few studies have attempted to understand the relationship between obesity and melanoma, the consequences of controlling body weight by reducing adiposity on cancer progression is not well understood. By employing animal models of obesity, we report that controlling obesity either by orlistat treatment or by restricting caloric intake significantly slows down melanoma progression. The diminished tumor progression was correlated with decreased fat mass (adiposity) in obese mice. Obesity associated factors contributing to tumor progression were decreased in the experimental groups compared to respective controls. In tumors, protein levels of fatty acid synthase (FASN), caveolin (Cav)-1 and pAkt, which are tumor promoting molecules implicated in melanoma growth under obese state, were decreased. In addition, increased necrosis and reduction in angiogenesis as well as proliferative markers PCNA and cyclin D1 were observed in tumors of the orlistat treated and/or calorically restricted obese mice. We observed that growth of melanoma cells cultured in conditioned medium (CM) from orlistat-treated adipocytes was reduced. Adipokines (leptin and resistin), via activating Akt and modulation of FASN as well as Cav-1 respectively, enhanced melanoma cell growth and proliferation. Together, we demonstrate that controlling body weight reduces adipose mass thereby diminishing melanoma progression. Therefore, strategic means of controlling obesity by reduced caloric diet or with antiobesity drugs treatment may render obesity-promoted tumor progression in check and prolong survival of patients.

Diet and exercise interventions among overweight and obese lactating women: randomized trial of effects on cardiovascular risk factors

Objective

To examine the effects of Diet (D) and Exercise (E) interventions on cardiovascular fitness, waist circumference, blood lipids, glucose metabolism, inflammation markers, insulin-like growth factor 1 (IGF-1) and blood pressure in overweight and obese lactating women.

Methods

At 10–14 wk postpartum, 68 Swedish women with a self-reported pre-pregnancy BMI of 25–35 kg/m² were randomized to a 12-wk behavior modification treatment with D, E, both or control using a 2×2 factorial design. The goal of D treatment was to reduce body weight by 0.5 kg/wk, accomplished by decreasing energy intake by 500 kcal/d and monitoring weight loss through self-weighing. The goal of E treatment was to perform 4 45-min walks per wk at 60–70% of max heart-rate using a heart-rate monitor. Effects were measured 12 wk and 1 y after randomization. General Linear Modeling was used to study main and interaction effects adjusted for baseline values of dependent variable.

Results

There was a significant main effect of the D treatment, decreasing waist circumference (P = 0.001), total cholesterol (P = 0.007), LDL-cholesterol (P = 0.003) and fasting insulin (P = 0.042), at the end of the 12-wk treatment. The decreased waist circumference (P<0.001) and insulin (P = 0.024) was sustained and HDL-cholesterol increased (P = 0.005) at the 1-y follow-up. No effects from the E treatment or any interaction effects were observed.

Conclusions

Dietary behavior modification that produced sustained weight loss among overweight and obese lactating women also improved risk factors for cardiovascular disease and type 2 diabetes. This intervention may not only reduce weight-related risks with future pregnancies but also long-term risk for metabolic disease.

Trial registration

ClinicalTrials.gov NCT01343238

Adiposopathy: how do diet, exercise and weight loss drug therapies improve metabolic disease in overweight patients?

An increase in bodyweight is generally associated with an increased risk of excessive fat-related metabolic diseases (EFRMD), including Type 2 diabetes mellitus, hypertension and dyslipidemia. However, not all patients who are overweight have EFRMD, and not all patients with EFRMD are significantly overweight. The adipocentric paradigm provides the basis for a unifying, pathophysiological process whereby fat gain in susceptible patients leads to fat dysfunction ('sick fat'), and wherein pathological abnormalities in fat function (adiposopathy) are more directly related to the onset of EFRMD than increases in fat mass (adiposity) alone. But just as worsening fat function worsens EFRMD, improved fat function improves EFRMD. Peroxisome proliferator-activated receptor-gamma agonists increase the recruitment, proliferation and differentiation of preadipocytes ('healthy fat') and cause apoptosis of hypertrophic and dysfunctional (including visceral) adipocytes resulting in improved fat function and improved metabolic parameters associated with EFRMD. Weight loss interventions, such as a hypocaloric diet and physical exercise, in addition to agents such as orlistat, sibutramine and cannabinoid receptor antagonists, may have favorable effects upon fat storage (lipogenesis and fat distribution), nutrient metabolism (such as free fatty acids), favorable effects upon adipose tissue factors involved in metabolic processes and inflammation, and enhanced 'cross-talk' with other major organ systems. In some cases, weight loss therapeutic agents may even affect metabolic parameters and adipocyte function independently of weight loss alone, suggesting that the benefit of these agents in improving EFRMD may go beyond their efficacy in weight reduction. This review describes how adiposopathy interventions may affect fat function, and thus improve EFRMD.

Long-term effects of weight-reducing drugs in hypertensive patients

BACKGROUND

All major guidelines for antihypertensive therapy recommend weight loss; anti-obesity drugs might be a helpful option.

PRIMARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight with orlistat, sibutramine or rimonabant on:- all cause mortality - cardiovascular morbidity - adverse events

SECONDARY OBJECTIVES

- changes in systolic and/or diastolic blood pressure - body weight reduction even though sibutramine and rimonabant have been withdrawn from the market.

SEARCH METHODS

Studies were obtained from computerised searches of Ovid MEDLINE, EMBASE, CENTRAL and from hand searches in reference lists and systematic reviews (status as of 17(th) August, 2012).

SELECTION CRITERIA

Randomized controlled trials in adult hypertensive patients with a study duration of at least 24 weeks comparing pharmacologic interventions (orlistat, sibutramine, rimonabant) for weight loss with placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Studies were pooled using fixed-effect meta-analysis in the absence of significant heterogeneity between studies (p>0.1). Otherwise, we used the random effects method and investigated the cause of heterogeneity.

MAIN RESULTS

After the updated literature search, the number of studies remained the same, with eight studies comparing orlistat or sibutramine to placebo fulfilling our inclusion criteria. No relevant studies investigating rimonabant for weight loss were identified. No study included mortality and cardiovascular morbidity as a pre-defined outcome. Incidence of gastrointestinal side effects was consistently higher in orlistat treated vs. placebo treated patients. Most frequent side effects with sibutramine were dry mouth, constipation and headache. Patients assigned to weight loss diets, orlistat or sibutramine reduced their body weight more effectively than patients in the usual care/placebo groups. Blood pressure reduction in patients treated with orlistat was for systolic blood pressure (SBP): weighted mean difference (WMD): -2.5 mm Hg; 95% CI, -4.0 to -0.9 mm Hg and for diastolic blood pressure (DBP): WMD -1.9 mm Hg; 95% CI, -3.0 to -0.9 mm Hg. Meta-analysis showed DBP increase under therapy with sibutramine: WMD +3.2 mm Hg; 95%CI +1.4 to +4.9 mm Hg.

AUTHORS' CONCLUSIONS

In patients with elevated blood pressure, orlistat and sibutramine reduced body weight to a similar degree. In the same trials, orlistat reduced blood pressure and sibutramine increased blood pressure. No trials investigating rimonabant in people with elevated blood pressure could be included. Long-term trials assessing the effect of orlistat, sibutramine and rimonabant on mortality and morbidity are lacking. Rimonabant and sibutramine have been withdrawn from the market for the time being.

Obesos diabéticos tipo 2 submetidos à derivação gástrica em Y-de-Roux: análise de resultados e influência nas complicações

RACIONAL: Cerca de 90% dos diabéticos tipo 2 são obesos ou têm sobrepeso. A evidente melhora clínica observada com o tratamento cirúrgico, como a derivação gástrica em Y-de-Roux, abriu caminhos para a pesquisa de outros fatores, que não somente a perda de peso, como responsáveis pelo retorno à euglicemia ou redução no tratamento medicamentoso. OBJETIVO: Avaliar a eficácia e segurança do tratamento cirúrgico do diabete melito em obesos com IMC acima de 35 Kg/m2 submetidos ao by-pass visando o controle do diabetes, perda de peso, melhora nos parâmetros laboratoriais e complicações do diabete. MÉTODOS: O protocolo do estudo foi aplicado em três momentos: o inicial; após perda de 10% do peso; e após um ano. RESULTADOS: Foram analisados 17 pacientes que perderam 10% de peso; 11,8% continuaram com necessidade de medicamento (p<0,001). O tempo para perda de peso foi de um mês, quando ocorreu redução significante da glicemia de jejum, do índice HOMA-IR, insulina, HbA1c, hemoglobina, AST, peptídeo C e uréia; não ocorreu variação do hematócrito, albumina, ALT e creatinina. Com um ano de acompanhamento, a série apresentou diferença significativa nas variáveis peso, IMC, glicemia, HbA1c, peptídeo C, insulina e o HOMA-IR. O percentual de pacientes com neuropatia (31,3%) foi menor que o número de casos no início do estudo (52,9%) (p>0,05). CONCLUSÃO: A derivação gástrica em Y-de-Roux é procedimento seguro, com bons resultados no controle do diabete em obesos com IMC acima de 35 Kg/m2.

Rapid and weight-independent improvement of glucose tolerance induced by a peptide designed to elicit apoptosis in adipose tissue endothelium

A peptide designed to induce apoptosis of endothelium in white adipose tissue (WAT) decreases adiposity. The goal of this work is to determine whether targeting of WAT endothelium results in impaired glucose regulation as a result of impaired WAT function. Glucose tolerance tests were performed on days 2 and 3 of treatment with vehicle (HF-V) or proapoptotic peptide (HF-PP) and mice pair-fed to HF-PP (HF-PF) in obese mice on a high-fat diet (HFD). Serum metabolic variables, including lipid profile, adipokines, individual fatty acids, and acylcarnitines, were measured. Microarray analysis was performed in epididymal fat of lean or obese mice treated with vehicle or proapoptotic peptide (PP). PP rapidly and potently improved glucose tolerance of obese mice in a weight- and food intake-independent manner. Serum insulin and triglycerides were decreased in HF-PP relative to HF-V. Levels of fatty acids and acylcarnitines were distinctive in HF-PP compared with HF-V or HF-PF. Microarray analysis in AT revealed that pathways involved in mitochondrial dysfunction, oxidative phosphorylation, and branched-chain amino acid degradation were changed by exposure to HFD and were reversed by PP administration. These studies suggest a novel role of the AT vasculature in glucose homeostasis and lipid metabolism.

Pragmatic study of orlistat 60 mg on abdominal obesity

BACKGROUND/OBJECTIVES

It is well established that combining a reduced calorie, low-fat diet with the lipase inhibitor orlistat results in significantly greater weight loss than placebo plus diet. This weight loss is accompanied by changes in adipose tissue (AT) distribution. As 60 mg orlistat is now available as an over-the-counter medication, the primary objective of this study was to determine whether 60 mg orlistat is effective as a weight loss option in a free-living community population with minimal professional input.

METHODS

AT and ectopic lipid content were measured using magnetic resonance imaging and (1)H MR spectroscopy, respectively, in 27 subjects following 3 months treatment with orlistat 60 mg and a reduced calorie, low-fat diet.

RESULTS

Significant reductions in intra-abdominal AT (-10.6%, P=0.023), subcutaneous (-11.7% P<0.0001) and pericardial fat (-9.8%, P=0.034) volumes and intrahepatocellular lipids (-43.3%, P=0.0003) were observed. These changes in body fat content and distribution were accompanied by improvements in plasma lipids and decreases in blood pressure and heart rate.

CONCLUSION

These findings suggest that over-the-counter 60 mg orlistat, in combination with the type of advice a subject could expect to be given when obtaining 60 mg orlistat in a community setting, does indeed result in potentially clinically beneficial changes in body composition and risk factors for metabolic diseases.

Rate of weight loss can be predicted by patient characteristics and intervention strategies

BACKGROUND

Although dietary weight-loss counseling usually employs a 500 to 1,000 kcal/day energy deficit to induce weight loss of 0.5 to 1 kg/week, this rate of weight loss is rarely achieved in research settings. Biological factors, such as changes in metabolic rate, are partly responsible, but would only account for a small deviation from expected weight loss. There must be other factors, behavioral or related to study design and implementation, that affect the rate of weight loss observed.

OBJECTIVE

To examine factors that influence the rate of weight loss obtained in clinical studies.

DESIGN

Thirty-five weight-loss studies published between 1995 and 2009 were identified that used dietary counseling to induce weight loss in healthy subjects. Studies were included if they had a duration of at least 6 weeks, used a strategy to counsel subjects to reduce free-living energy intakes, and reported weight-loss data based on a completers analysis. Variables that were associated with the rate of weight loss among age, sex (percent female subjects), initial body weight, frequency of dietary counseling, placebo use, exercise level, study length, and prescribed energy deficit were examined using linear regression analysis.

RESULTS

Study length was negatively related to the rate of weight loss (P<0.0001), whereas subject age (P<0.002), subject age squared (P=0.0073), initial body weight (P=0.0003), frequency of dietary counseling (P=0.0197), and prescribed energy deficit (P<0.0001) were positively related to the rate of weight loss observed in clinical studies.

CONCLUSIONS

These findings provide a tool for investigators and clinical dietitians to predict the rate of weight loss that can be expected within a population given the age, initial body weight, frequency of dietary counseling, and energy deficit prescription. These data from clinical studies suggest that the rate of weight loss is greater in older and heavier subjects and with higher contact frequency and caloric restriction.

Orlistat 60 mg reduces visceral adipose tissue: a 24-week randomized, placebo-controlled, multicenter trial

It is well established that abdominal obesity or upper body fat distribution is associated with increased risk of metabolic and cardiovascular disease. The purpose of the present study was to determine if a 24 week weight loss program with orlistat 60 mg in overweight subjects would produce a greater change in visceral adipose tissue (VAT) as measured by computed tomography (CT) scan, compared to placebo. The effects of orlistat 60 mg on changes in total fat mass (EchoMRI-AH and BIA), ectopic fat (CT) and glycemic variables were assessed. One-hundred thirty-one subjects were randomized into a multicenter, double-blind placebo controlled study in which 123 subjects received at least one post baseline efficacy measurement (intent-to-treat population). Both orlistat-and placebo-treated subjects significantly decreased their VAT at 24 weeks with a significantly greater loss of VAT by orlistat treated subjects (-15.7% vs. -9.4%, P < 0.05). In addition, orlistat-treated subjects had significantly greater weight loss (-5.93 kg vs. -3.94 kg, P < 0.05), total fat mass loss (-4.65 kg vs. -3.01 kg, P < 0.05) and trended to a greater loss of intermuscular adipose tissue and content of liver fat compared with placebo-treated subjects. This is the first study to demonstrate that orlistat 60 mg significantly reduces VAT in addition to total body fat compared to placebo treated subjects after a 24 week weight loss program. These results suggest that orlistat 60 mg may be an effective weight loss tool to reduce metabolic risk factors associated with abdominal obesity.

Genetic variation in PNPLA3 (adiponutrin) confers sensitivity to weight loss-induced decrease in liver fat in humans

BACKGROUND

The rs738409 C→G single nucleotide polymorphism in the patatin-like phospholipase domain-containing 3 (PNPLA3; adiponutrin) leads to a missense mutation (I148M), which is associated with increased liver fat but not insulin resistance. The I148M mutation impedes triglyceride hydrolysis in vitro, and its carriers have an increased risk of developing severe liver disease.

OBJECTIVE

We explored whether the rs738409 PNPLA3 G allele influences the ability of weight loss to decrease liver fat or change insulin sensitivity.

DESIGN

We recruited 8 subjects who were homozygous for the rs738409 PNPLA3 G allele (PNPLA3-148MM) and 10 who were homozygous for the rs738409 PNPLA3 C allele (PNPLA3-148II). To allow comparison of changes in liver fat, the groups were matched with respect to baseline age, sex, body mass index, and liver fat. The subjects were placed on a hypocaloric low-carbohydrate diet for 6 d. Liver fat content (proton magnetic resonance spectroscopy), whole-body insulin sensitivity of glucose metabolism (euglycemic clamp technique), and lipolysis ([(2)H(5)]glycerol infusion) were measured before and after the diet.

RESULTS

At baseline, fasting serum insulin and C-peptide concentrations were significantly lower in the PNPLA3-148MM group than in the PNPLA3-148II group, as predicted by study design. Weight loss was not significantly different between groups (PNPLA3-148MM: -3.1 ± 0.5 kg; PNPLA3-148II: -3.1 ± 0.4 kg). Liver fat decreased by 45% in the PNPLA3-148MM group (P < 0.001) and by 18% in the PNPLA3-148II group (P < 0.01).

CONCLUSION

Weight loss is effective in decreasing liver fat in subjects who are homozygous for the rs738409 PNPLA3 G or C allele. This trial was registered at www.hus.fi as 233775.

Nutritional modulation of nonalcoholic fatty liver disease and insulin resistance: human data

PURPOSE OF REVIEW

Concomitant with the obesity epidemic, a fatty liver due to nonalcoholic causes has become the most common liver disorder. Nonalcoholic fatty liver disease (NAFLD) covers a range from benign steatosis to nonalcoholic steatohepatitis (NASH), which in turn may progress to cirrhosis. NAFLD predicts, independent of obesity, the metabolic syndrome and type 2 diabetes and can progress to cirrhosis. This review focuses on studies in humans addressing effects of dietary changes in NAFLD.

RECENT FINDINGS

Cross-sectionally, increased intake of fructose and simple sugars characterizes patients with NAFLD compared with weight-matched controls. Increased fructose intake is also associated with hepatic insulin resistance and fibrosis severity in NASH. Intake of saturated fat may also be increased in NAFLD. Dietary intervention studies have shown that liver volume and fat content changes significantly within a few days in response to caloric restriction or excess despite no or small changes in body weight. Weight loss by bariatric surgery decreases liver fat and inflammation but effects on fibrosis are uncertain. Hepatic insulin sensitivity generally changes in parallel with changes in liver fat content in NAFLD. Human data are limited regarding effects of isocaloric changes in diet composition on liver fat content.

SUMMARY

Maintenance of normal body weight and avoidance of intake of excess lipogenic simple sugars would seem beneficial for prevention of NAFLD and its metabolic consequences.

Surgical removal of omental fat does not improve insulin sensitivity and cardiovascular risk factors in obese adults

BACKGROUND & AIMS

Visceral adipose tissue (VAT) is an important risk factor for the metabolic complications associated with obesity. Therefore, a reduction in VAT is considered an important target of obesity therapy. We evaluated whether reducing VAT mass by surgical removal of the omentum improves insulin sensitivity and metabolic function in obese patients.

METHODS

We conducted a 12-month randomized controlled trial to determine whether reducing VAT by omentectomy in 22 obese subjects increased their improvement following Roux-en-Y gastric bypass (RYGB) surgery in hepatic and skeletal muscle sensitivity to insulin study 1. Improvement was assessed by using the hyperinsulinemic-euglycemic clamp technique. We also performed a 3-month, longitudinal, single-arm study to determine whether laparoscopic omentectomy alone, in 7 obese subjects with type 2 diabetes mellitus (T2DM), improved insulin sensitivity study 2. Improvement was assessed by using the Frequently Sampled Intravenous Glucose Tolerance Test.

RESULTS

The greater omentum, which weighed 0.82 kg (95% confidence interval: 0.67-0.97), was removed from subjects who had omentectomy in both studies. In study 1, there was an approximate 2-fold increase in muscle insulin sensitivity (relative increase in glucose disposal during insulin infusion) and a 4-fold increase in hepatic insulin sensitivity 12 months after RYGB alone and RYGB plus omentectomy, compared with baseline values (P<.001). There were no significant differences between groups (P>.87) or group x time interactions (P>.36). In study 2, surgery had no effect on insulin sensitivity (P=.844) or use of diabetes medications.

CONCLUSIONS

These results demonstrate that decreasing VAT through omentectomy, alone or in combination with RYGB surgery, does not improve metabolic function in obese patients.

Thiazolidinediones and the liver in humans

PURPOSE OF REVIEW

To review recent advances in the understanding of the mechanism of action of thiazolidinediones (TZDs) in humans.

RECENT FINDINGS

The liver is characterized by excess fat accumulation due to nonalcoholic causes (non-alcoholic fatty liver disease) in most patients with the metabolic syndrome and type 2 diabetes. Simple steatosis can progress to nonalcoholic steatohepatitis (NASH) and cirrhosis. Both of the commercially available antihyperglycemic TZD agonists, pioglitazone and rosiglitazone, are markedly effective in reducing liver fat content by 30-50% and sensitizing the liver to insulin. This reduces the amount of endogenous and exogenous insulin needed to inhibit hepatic glucose production. Decreases in liver fat are closely correlated with increases in serum adiponectin, which is an insulin-sensitizing adipokine produced exclusively by adipose tissue. Both TZDs are equally effective in reducing liver fat. Regarding lipid metabolism, enhanced hepatic insulin sensitivity would be predicted to lower VLDL and serum triglycerides and increase HDL-cholesterol. Pioglitazone and rosiglitazone have different effects on serum lipids, which cannot be attributed to simple insulin sensitization. Very recently, TZDs have been shown to reduce not only steatosis but possibly also hepatocellular damage in NASH.

SUMMARY

Given the uncertainties in benefits of TZDs in reducing cardiovascular disease in type 2 diabetes, as well as other side-effects (heart failure, fractures), TZDs may in the future be increasingly used in patients with nonalcoholic steatohepatitis.

Long-term effects of weight-reducing drugs in hypertensive patients

BACKGROUND

All major guidelines for antihypertensive therapy recommend weight loss; anti-obesity drugs might be a helpful option.

PRIMARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight with orlistat, sibutramine or rimonabant on:- all cause mortality - cardiovascular morbidity - adverse events

SECONDARY OBJECTIVES

- changes in systolic and/or diastolic blood pressure - body weight reduction

SEARCH STRATEGY

Studies were obtained from computerised searches of Ovid MEDLINE, EMBASE, CENTRAL and from hand searches in reference lists and systematic reviews.

SELECTION CRITERIA

Randomized controlled trials in adult hypertensive patients with a study duration of at least 24 weeks comparing pharmacologic interventions (orlistat, sibutramine, rimonabant) for weight loss with placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Studies were pooled using fixed-effect meta-analysis in the absence of significant heterogeneity between studies (p>0.1). Otherwise, we used the random effects method and investigated the cause of heterogeneity.

MAIN RESULTS

Eight studies comparing orlistat or sibutramine to placebo fulfilled our inclusion criteria. No relevant studies investigating rimonabant for weight loss were identified. No study included mortality and cardiovascular morbidity as a pre-defined outcome. Incidence of gastrointestinal side effects was consistently higher in orlistat treated vs. placebo treated patients. Most frequent side effects with sibutramine were dry mouth, constipation and headache. Patients assigned to weight loss diets, orlistat or sibutramine reduced their body weight more effectively than patients in the usual care/placebo groups. Blood pressure reduction in patients treated with orlistat was for systolic blood pressure (SBP): weighted mean difference (WMD): -2.5 mm Hg; 95% CI, -4.0 to -0.9 mm Hg and for diastolic blood pressure (DBP): WMD -1.9 mm Hg; 95% CI, -3.0 to -0.9 mm Hg. Meta-analysis showed DBP increase under therapy with sibutramine: WMD +3.2 mm Hg; 95%CI +1.4 to +4.9 mm Hg.

AUTHORS' CONCLUSIONS

In patients with elevated blood pressure, orlistat and sibutramine reduced body weight to a similar degree. In the same trials, orlistat reduced blood pressure and sibutramine increased blood pressure. No trials investigating rimonabant in people with elevated blood pressure could be included. Long-term trials assessing the effect of orlistat, sibutramine and rimonabant on mortality and morbidity are needed.

Rimonabant prevents additional accumulation of visceral and subcutaneous fat during high-fat feeding in dogs

We investigated whether rimonabant, a type 1 cannabinoid receptor antagonist, reduces visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in dogs maintained on a hypercaloric high-fat diet (HHFD). To determine whether energy expenditure contributed to body weight changes, we also calculated resting metabolic rate. Twenty male dogs received either rimonabant (1.25 mg.kg(-1).day(-1), orally; n = 11) or placebo (n = 9) for 16 wk, concomitant with a HHFD. VAT, SAT, and nonfat tissue were measured by magnetic resonance imaging. Resting metabolic rate was assessed by indirect calorimetry. By week 16 of treatment, rimonabant dogs lost 2.5% of their body weight (P = 0.029), whereas in placebo dogs body weight increased by 6.2% (P < 0.001). Rimonabant reduced food intake (P = 0.027), concomitant with a reduction of SAT by 19.5% (P < 0.001). In contrast with the VAT increase with placebo (P < 0.01), VAT did not change with rimonabant. Nonfat tissue remained unchanged in both groups. Body weight loss was not associated with either resting metabolic rate (r(2) = 0.24; P = 0.154) or food intake (r(2) = 0.24; P = 0.166). In conclusion, rimonabant reduced body weight together with a reduction in abdominal fat, mainly because of SAT loss. Body weight changes were not associated with either resting metabolic rate or food intake. The findings provide evidence of a peripheral effect of rimonabant to reduce adiposity and body weight, possibly through a direct effect on adipose tissue.

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.

The first decade of sibutramine and orlistat: a reappraisal of their expanding roles in the treatment of obesity and associated conditions

Ancillary therapies for weight management, consisting mainly of diet and exercise programs that incorporate variable levels of lifestyle modification techniques, are frequently ineffective to achieve clinically meaningful weight loss and maintenance. Although pharmacological treatment of obesity is widely used in most countries, the number of available drugs is still very limited. The most widely used anti-obesity agents are sibutramine and orlistat, both available in clinical practice for about a decade. A large number of clinical trials have demonstrated that both agents are safe and well tolerated, with a level of efficacy in the moderate weight loss recommended by the most relevant clinical guidelines. Several studies have assessed the efficacy and safety of sibutramine and orlistat in adolescents and also for the treatment of some associated conditions in adults, including type 2 diabetes, polycystic ovary syndrome and binge eating disorder. The positive results of these studies suggest an expanding role for both agents, not only for the treatment of obesity, but also for associated conditions. After the efficacy of orlistat for the prevention of type 2 diabetes demonstrated in the XENDOS study, the results of SCOUT study are awaited for a better evaluation of sibutramine impact on cardiovascular outcomes.

Altered alanine aminotransferase and gamma-glutamyl transpeptidase in women with history of preeclampsia: association with waist-to-hip ratio and body mass index

OBJECTIVE

Preeclampsia (PE), mostly when associated with HELLP syndrome, together with acute fatty liver of pregnancy, are the main causes of severe hepatic failure in pregnancy. Despite the number of studies in pregnancies complicated with PE, there are a few studies that focused on the evaluation of the hepatic function of these women several years after delivery. In this way, we evaluated circulating levels of AST, ALT, gammaGT and CRP several years after preeclamptic pregnancy to verify if these parameters are altered.

METHODS

Eighty-nine women with previous PE and 60 women without medical complications were invited to the research centers. After the physical examination, blood was drawn for biochemical measurements. Plasma CRP levels and serum concentration of AST, ALT, gammaGT were measured by automated enzymatic assays.

RESULTS

Systolic and diastolic blood pressures were significantly higher in women with history of PE than in control group as well as BMI and waist-to-hip ratio. ALT and gammaGT were significantly higher in women with previous history of PE, whereas AST and CRP presented similar levels between the two groups. Data revealed statistically significant positive correlations between ALT and gammaGT with waist-to-hip ratio and BMI. Positive correlations were also found between BMI and AST and CRP.

CONCLUSION

It is possible that the increase in ALT and gammaGT levels is due to being overweight or through accumulation of visceral fat. Unaltered values of CRP suggest that the higher ALT and gammaGT values found in women with history of PE are not associated with inflammation.

Hypertension and hepatic steatosis

Hepatic steatosis (fatty liver) is increasingly recognized as a major component of the metabolic (insulin resistance) syndrome. It can progress to cirrhosis and hepatocellular carcinoma, leading to liver-related mortality. Increasing evidence shows a significant association between hepatic steatosis and hypertension; both are linked to the metabolic syndrome. This review discusses the evidence to support this association, and reviews the diagnosis and management of hepatic steatosis.

Orlistat for overweight subjects with nonalcoholic steatohepatitis: A randomized, prospective trial

The aim of this study was to determine if orlistat, an inhibitor of fat absorption, combined with caloric restriction in overweight subjects with nonalcoholic steatohepatitis results in weight loss and improved liver histology. Fifty overweight subjects (body mass index = >or=27) with biopsy proven nonalcoholic steatohepatitis were randomized to receive a 1,400 Kcal/day diet plus vitamin E (800 IU) daily with or without orlistat (120 mg three times a day) for 36 weeks. Liver biopsies were repeated at week 36. Twenty-three subjects in the orlistat/diet/vitamin E group and 18 in the diet/vitamin E group completed the study. The mean age was 47 +/- 9.0 (standard deviation) years and mean body mass index was 36.4 +/- 6.3 kg/m(2). Four subjects were diabetic. The orlistat group lost a mean of 8.3% body weight compared to 6.0% in the diet plus vitamin E group (not significant). Both groups also had similarly improved serum aminotransferases, hepatic steatosis, necroinflammation, ballooning, and nonalcoholic fatty liver disease activity scores. Stratified according to weight loss instead of treatment group, a loss of >or=5% body weight (n = 24) compared to <5% body weight (n = 17) correlated with improvement in insulin sensitivity (P = 0.001) and steatosis (P = 0.015). Comparing subjects who lost >or=9% of body weight (n = 16), to those that did not (n = 25), improved insulin sensitivity (P < 0.001), adiponectin (P = 0.03), steatosis (P = 0.005), ballooning (P = 0.04), inflammation (P = 0.045), and nonalcoholic fatty liver disease activity score (P = 0.009) were seen. Increases in adiponectin strongly correlated with improved ballooning and nonalcoholic fatty liver disease activity score (P = 0.03). Orlistat did not enhance weight loss or improve liver enzymes, measures of insulin resistance, and histopathology. However, subjects who lost >or=5% of body weight over 9 months improved insulin resistance and steatosis, and those subjects who lost >or=9% also achieved improved hepatic histologic changes.

Long-term effects of lipase inhibition by orlistat on gastric emptying and orocecal transit time of a solid meal

BACKGROUND

We assessed the impact of a prolonged lipase inhibition upon gastric emptying (GE) and orocecal transit time (OCTT) of a 355-kcal low-fat solid meal.

METHODS

In double-blind manner, 40 obese women BMI > 30 kg/m2, randomly allocated into two equal groups, took orally t.i.d. 120 mg orlistat or placebo during 8 weeks of a weight-reducing management. At randomization and after 2 months, GE was measured simultaneously with OCTT by means of a 13C-octanoic acid and a hydrogen breath test, respectively. Lipolytic activity was evaluated with a 13C-mixed triglyceride breath test (13C-MTGBT).

RESULTS

A profound lipase inhibition by orlistat was confirmed by a 79.5% +/- 16.9% reduction of the cumulative 6-h 13C recovery with 13CMTGBT. GE remained unchanged either in the orlistat (T1/2, 188 +/- 35 min start versus 198 +/- 36 min end) or the placebo (T1/2, 191 +/- 35 min start versus 180 +/- 39 min end) group. OCTT increased from 208 +/- 54 min to 271 +/- 64 min (P < 0.01) after orlistat treatment and did not change significantly (216 +/- 76 vs. 234 +/- 72 min) in the placebo group.

CONCLUSIONS

No adverse effect on the GE and a moderate prolongation of the OCTT of a low-fat solid meal is to be expected under a prolonged treatment with orlistat at a typical dosage regimen.

Factors associated with percent change in visceral versus subcutaneous abdominal fat during weight loss: findings from a systematic review

BACKGROUND

Visceral adipose tissue (VAT) is associated with greater obesity-related metabolic disturbance. Many studies have reported preferential loss of VAT with weight loss.

OBJECTIVE

This systematic review looks for factors associated with preferential loss of VAT relative to subcutaneous abdominal fat (SAT) during weight loss.

DESIGN

Medline and Embase were searched for imaging-based measurements of VAT and subcutaneous abdominal adipose tissue (SAT) before and after weight loss interventions. We examine for factors that influences the percentage change in VAT versus SAT (%deltaV/%deltaS) with weight loss. Linear regression analyses were performed on the complete data set and on subgroups of studies. Factors examined included percentage weight loss, degree of caloric restriction, exercise, initial body mass index (BMI), gender, time of follow-up and baseline VAT/SAT.

RESULTS

There were 61 studies with a total of 98 cohort time points extracted. Percentage weight loss was the only variable that influenced %deltaV/%deltaS (r=-0.29, P=0.005). Modest weight loss generated preferential loss of VAT, but with greater weight loss this effect was attenuated. The method of weight loss was not an influence with one exception. Very-low-calorie diets (VLCDs) provided exceptional short-term (<4 weeks) preferential VAT loss. But this effect was lost by 12-14 weeks.

CONCLUSIONS

Visceral adipose tissue is lost preferentially with modest weight loss, but the effect is attenuated with greater weight loss. Acute caloric restriction, using VLCD, produces early preferential loss of VAT. These observations may help to explain the metabolic benefits of modest weight loss.

Drugs in the treatment of obesity: sibutramine, orlistat and rimonabant

Background

Modification of lifestyle is the main therapeutical approach in the treatment of obesity, but use to fail on long terms of time. Addition of anti-obesity drugs allows keeping the weight loss during years and improving obesity-related comorbidities.

Methods

This review is an actualisation on efficacy, safety and tolerability of the approved drugs on the long-term treatment of obesity (orlistat and sibutramine). New indications and effects of their use far beyond the weight loss are as well commented. Finally, potential benefits of the administration of CB1 antagonist rimonabant on the weight loss and cardiometabolic risk factors are analysed in detail.

Discussion

A decade of experience on the use of orlistat and sibutramine has demonstrated their higher efficacy on the weight loss when compared to placebo either on adult or teenage population as well as safety and tolerability on long-term administration. Beneficial effects on the lipid profile, glycosilated haemoglobin on diabetic patients, blood pressure and levels of inflammatory cytokines, contribute to decrease the cardiovascular risk on obese patients. Phase III clinical trials using rimonabant show additional benefits to the expected weight loss, mainly reducing visceral fat and cardiometabolic risk factors.

Conclusion

Pharmacological treatment of obesity must be considered as a therapeutical tool that has to be used together with long-term lifestyle changes, contributing to the body weight reduction as well as to the improvement of the cardiometabolic risk related to obesity.

Changes in body composition with weight loss: obese subjects randomized to surgical and medical programs

OBJECTIVE

To assess changes in body composition with weight loss in obese subjects randomized to a laparoscopic adjustable gastric band surgical program or a medical program using a very-low-energy diet and orlistat.

RESEARCH METHODS AND PROCEDURES

Using body composition measurements by DXA, neutron activation for total body nitrogen, and whole body gamma counting for total body potassium, we studied changes in fat mass, fat distribution, fat-free mass, total bone mineral content, total body protein, and body cell mass at 6 (n = 61 paired) and 24 months (n = 53 paired) after randomization.

RESULTS

At 24 months, the surgical group had lost significantly more weight (surgical, 20.3 +/- 6.5 kg; medical, 5.9 +/- 8.0 kg). There was favorable fat-free mass to fat mass loss ratios for both groups (surgical, 1:5.5; medical, 1:5.9). Changes in total body nitrogen or potassium were favorable in each group. A small reduction in mean bone mineral content occurred throughout the study but was not associated with extent of weight loss or treatment group. At 6 months, weight loss for both groups was similar (surgical, 14.1 +/- 4.5 kg; medical, 13.3 +/- 7.3 kg). The medical program subjects lost less fat-free mass and skeletal muscle and had increased total body protein. The proportion of body fat to limb fat remained remarkably constant throughout the study.

DISCUSSION

Weight loss programs used in this study induced fat loss without significant deleterious effects on the components of fat-free mass.

Abdominal fat-water separation with SSFP at 3 Tesla

The ability of the phase-sensitive steady-state free precession (SSFP) technique to distinguish subcutaneous and visceral adipose tissue in the abdomen at 3 T was evaluated. A phased array receiver radiofrequency coil and a commercially available SSFP sequence were used for imaging. The raw image data were postprocessed to generate fat-only and water-only images. A postprocessing algorithm that is computationally efficient and robust is presented. The postprocessing technique separates the fat and water pixels automatically without any user interference. The feasibility of the technique is demonstrated in vivo with breath-hold abdomen images. The short scan time and the ease of use of this technique are well suited to the quantification of body fat distribution in children.

An update on the pharmacological treatment of obesity

OBJECTIVE

To review the commonly utilized pharmacological options for the treatment of overweight and obese patients in the United States.

METHODS

A MEDLINE and EMBASE search, in English, between January 1995 and November 2005 was conducted using the terms, "anti-obesity agents", "orlistat", "sibutramine", and "phentermine". References cited in relevant studies and reviews were also examined for additional clinical trials to be included in the review.

RESULTS

There are several pharmacological options currently available for the treatment of overweight and obese individuals in the United States, including phentermine, sibutramine, and orlistat, with only sibutramine and orlistat being indicated for use in the long term (> 6 months). However, none of these medications have proven to be more effective than another for the indication of weight loss, each with a very similar maximum weight loss potential. Therefore choosing a weight loss medication should be patient specific and based on its pharmacological profile, including mechanism of action and potential adverse effects. Most importantly, it is imperative to realize that these agents are only indicated for use when combined with lifestyle modifications. Most studies have indicated that maximum benefits from any of these medications are only shown when taken in addition to a hypocaloric diet.

CONCLUSION

It has been shown that the combination of lifestyle changes and pharmacological treatment leads to a greater decrease in total body weight loss. Treatment with anti-obesity agents is associated with side effects and an increased cost in health care. These factors must be weighed prior to initiating anti-obesity treatment.

Antiobesity action of ɛ-polylysine, a potent inhibitor of pancreatic lipase

In vitro, -polylysine (EPL) strongly inhibited the hydrolysis of trioleoylglycerol emulsified with phosphatidylcholine (PC) and taurocholate by either pancreatic lipase or carboxylester lipase. The EPL concentration required for 50% inhibition of pancreatic lipase, 0.12 microM, was eight times lower than the concentration of orlistat required for the same effect. The 50% inhibition concentration by EPL was affected by emulsifier species: it was increased approximately 150 times, 70 times, and 230 times on gum arabic, phosphatidylserine, and phosphatidic acid emulsion, respectively, compared with PC emulsion. The 50% inhibition concentration by orlistat was little changed by emulsifier species. Gel-filtration experiments suggested that EPL did not bind strongly to pancreatic lipase, whereas orlistat did. To test the effect of EPL on obesity, mice were fed a high-fat diet containing 0.1, 0.2, or 0.4% EPL. EPL prevented the high-fat diet-induced increase in body weight and weight of the liver and visceral adipose tissues (epididymal and retroperitoneal). EPL also decreased plasma triacylglycerol and plasma cholesterol concentrations and liver triacylglycerol content after they had been increased by the high-fat diet. The fecal weights of mice were increased by the high-fat diet containing EPL compared with the high-fat diet alone. Fecal lipid was also increased by the diet containing EPL. These data clearly show that EPL has an antiobesity function in mice fed a high-fat diet that acts by inhibiting intestinal absorption of dietary fat.

Non-alcoholic fatty liver disease (NAFLD)--a novel common aspect of the metabolic syndrome

Non-alcoholic fatty liver disease (NAFLD) is emerging as one of the most common liver disorders claiming the urgent attention of both medical professionals and the public sphere because of the imminent epidemic of advanced liver injury that appendages epidemic of obesity. Recent research reveals simple triglyceride accumulation in hepatocytes (i.e., liver steatosis) frequently becoming complicated by inflammation (i.e., non-alcoholic steatohepatitis, or NASH) that may progress into more advanced stages of the disease including cirrhosis or, eventually, hepatocellular carcinoma. The exact mechanisms of the progression of NAFLD into overt NASH and advanced disease stages are largely unknown. There is urgent need in terms of both intensive research pursuits and effective practical measures to deal with this common threat.

Correlations between measures of insulin sensitivity and weight loss

OBJECTIVE

Many formulas have been proposed to calculate insulin sensitivity and studies have shown their effectiveness. However, few studies have been done to compare formulas.

METHODS

Seventy-two obese participants completed a randomized weight loss study. Weight loss, change in body fat and change in waist circumference were used as surrogates for change in insulin sensitivity. Correlation coefficients were calculated for each of these surrogates with proposed formulas for insulin sensitivity found in the literature.

RESULTS

The change in insulin sensitivity using the formula proposed by McAuley (exp(2.63-0.28 x ln(fasting insulin)-0.31 x ln(fasting triglyceride in mmol/l)) showed the greatest correlation with weight loss (r=-0.59, p<0.0001) and was statistically superior to change in fasting glucose, fasting insulin and homeostasis model assessment (HOMA).

CONCLUSIONS

The insulin sensitivity formula proposed by McAuley provides an accurate means of detecting insulin resistance. As it does not require a glucose tolerance test, it is also easier and less expensive than most other formulas. Use of this formula rather than fasting glucose would detect many more patients with insulin resistance who are at risk for subsequent diabetes and other complications.