Orlistat and sibutramine beyond weight loss

Caffeine: a potential mechanism for anti-obesity

Obesity refers to the excessive accumulation of fat caused by a long-term imbalance between energy intake (EI) and energy expenditure (EE). Over recent years, obesity has become a major public health challenge. Caffeine is a natural product that has been demonstrated to exert anti-obesity effects; however, the mechanisms responsible for the effect of caffeine on weight loss have yet to be fully elucidated. Most obesity-related deaths are due to cardiovascular disease. Recent research has demonstrated that caffeine can reduce the risk of death from cardiovascular disease; thus, it can be hypothesized that caffeine may represent a new therapeutic agent for weight loss. In this review, we synthesize data arising from clinical and animal studies over the last decade and discuss the potential mechanisms by which caffeine may induce weight loss, focusing particularly on increasing energy consumption, suppressing appetite, altering lipid metabolism, and influencing the gut microbiota. Finally, we summarize the major challenges associated with caffeine and anti-obesity research and highlight possible directions for future research and development.

"Anti-obesity medications" or "medications to treat obesity" instead of "weight loss drugs" - why language matters - an official statement of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM)

Obesity is largely undertreated, in part because of the stigma surrounding the disease and its treatment. The use of the term "weight loss drugs" to refer to medications for the treatment of obesity may contribute to this stigma, leading to the idea that anyone who wants to lose weight could use them and that short-term use, only in the active weight loss phase would be enough. On the contrary, the use of terms such as "medications to treat obesity" or "anti-obesity medications" conveys the idea that the treatment is directed at the disease rather than the symptom. This joint statement by the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM) intends to alert the press, healthcare professionals and scientific community about the importance of the appropriate use of language, with the aim of improving obesity care.

Obesity Therapy: How and Why?

Background:

Obesity represents the second preventable mortality cause worldwide, and is very often associated with type 2 Diabetes Mellitus (T2DM). The first line treatment is lifestyle modification to weight-loss, but for those who fail to achieve the goal or have difficulty in maintaining achieved results, pharmacological treatment is needed. Few drugs are available today, because of their side effects.

Objective:

We aim to review actual pharmacological management of obese patients, highlighting differences between Food and Drug Administration - and European Medicine Agency-approved molecules, and pointing out self-medications readily obtainable and widely distributed.

Methods:

Papers on obesity, weight loss, pharmacotherapy, self- medication and diet-aid products were selected using Medline. Research articles, systematic reviews, clinical trials and meta-analyses were screened.

Results:

Anti-obesity drugs with central mechanisms, such as phentermine and lorcaserin, are available in USA, but not in Europe. Phentermine/topiramate and naltrexone/bupropion combinations are now available, even though the former is still under investigation from EMA. Orlistat, with peripheral mechanisms, represents the only drug approved for weight reduction in adolescents. Liraglutide has been approved at higher dose for obesity. Anti-obesity drugs, readily obtainable from the internet, include crude-drug products and supplements for which there is often a lack of compliance to national regulatory standards.

Conclusion:

Mechanisms of weight loss drugs include the reduction of energy intake or the increase in energy expenditure and sense of satiety as well as the decrease of hunger or the reduction in calories absorption. Few drugs are approved, and differences exist between USA and Europe. Moreover, herbal medicines and supplements often sold on the internet and widely used by obese patients, present a risk of adverse effects.

Combination therapy with catechins and caffeine inhibits fat accumulation in 3T3-L1 cells

Catechins and caffeine, which are green tea components, have a slimming effect; however, the combinational effect of fat metabolism in 3T3-L1 cells remains unclear. In the present study, 3T3-L1 cells were treated with catechins and caffeine in combination, and it was found that combination therapy with catechins and caffeine markedly reduced intracellular fat accumulation, mRNA expression levels of peroxisome proliferator-activated receptor-γ and CCAAT/enhancer-binding protein α in the early stage of cell differentiation were significantly reduced, and mRNA expression of fatty acid synthetase(FAS) andglycerol-3-phosphate dehydrogenase protein expression levels of FAS were downregulated. Noradrenaline-induced lipolysis was enhanced by caffeine, which markedly increased the protein expression of adipose triglyceride lipase and hormone sensitive lipase. These results indicated that combination therapy with catechins and caffeine synergistically inhibited lipid accumulation by regulating the gene and protein expression levels of lipid metabolism-related enzymes. Therefore, catechins and caffeine combination therapy has potential as a functional food that may be used to prevent obesity and lifestyle-associated diseases.

Anti-obesity effects of artificial planting blueberry (Vaccinium ashei) anthocyanin in high-fat diet-treated mice

This study aimed to evaluate the anti-obesity effects of artificial planting blueberry (Vaccinium ashei) anthocyanin (BA) in high-fat diet-induced obese male C57BL/6 mice. BA at doses of 50, 100, and 200 mg/kg was supplemented in the daily food of obese C57BL/6 mice during an 8-week experiment. Our findings indicate that consumption of BA at high doses reduced body weight by 19.4%, whereas both low and middle doses did not affect the body weight. Furthermore, BA supplementation at high dose could effectively decrease serum glucose, attenuate epididymal adipocytes, improve lipid profiles, and significantly down-regulate expression levels of TNFα, IL-6 PPARγ, and FAS genes. Therefour, BA might alter bodyweight by suppressing fatty acid synthesis and alleviating inflammation.

Benefit-risk assessment of orlistat in the treatment of obesity

Orlistat, an inhibitor of intestinal lipase, has been available for the treatment of obesity for nearly two decades. In conjunction with a hypocaloric diet, orlistat treatment results in a placebo-subtracted reduction in body weight of around 3 kg at 1 year, and increases the likelihood of achieving clinically significant (≥5%) weight loss by around 20%. Orlistat-induced weight loss also confers modest improvements in systolic and diastolic blood pressure, low-density lipoprotein (LDL) cholesterol, glycemic parameters, and progression to diabetes in people with impaired glucose tolerance. Overall, it has a good safety profile, and serious adverse events (including reports of severe kidney and liver injury) are rare. However, a high rate of gastrointestinal side effects limits adherence to treatment.

Large pore mesoporous silica induced weight loss in obese mice

Background: There is a need for medical treatments to curb the rising rate of obesity. Weight reduction is correlated with a decrease in associated risk factors and cholesterol levels in humans. Amorphous silica particles have been found to exert a hypocholesterolemic effect in humans, making them popular dietary additives. Aim: To investigate the effect of mesoporous silica, which possess sharp pore size distributions, on: weight loss, cholesterol, triglycerides and glucose blood levels in obese mice. Materials & methods: Mesoporous silicas with differing pore size were mixed in the high-fat diet of obese mice. Results: Animals receiving large pore mesoporous silica with a high-fat diet show a significant reduction in body weight and fat composition, with no observable negative effects. Conclusion: Pore size is an important parameter for reduction of body weight and body fat composition by mesoporous silica, demonstrating promising signs for the treatment of obesity.

Original submitted 30 January 2013; Revised submitted 20 June 2013

Anti-Obesity Drugs: A Review about Their Effects and Safety

The current recommendations for the treatment of obese people include increased physical activity and reduced calories intake. When the behavioral approach is not sufficient, a pharmacologic treatment is recommended. In past years, numerous drugs have been approved for the treatment of obesity; however, most of them have been withdrawn from the market because of their adverse effects. In fact, amphetamine, rimonabant and sibutramine licenses have been withdrawn due to an increased risk of psychiatric disorders and non-fatal myocardial infarction or stroke. Even if orlistat is not as effective as other drugs in reducing body weight, orlistat is presently the only available choice for the treatment of obesity because of its safety for cardiovascular events and positive effects on diabetic control. Hopefully, more effective and better tolerated anti-obesity drugs will be developed through an improved understanding of the multiple mechanisms and complex physiological systems targeting appetite.

Cardiovascular risk-benefit profile of sibutramine

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

Clinical and economic considerations of antiobesity treatment: a review of orlistat

The objective of this study was to review the current knowledge about the use of orlistat from clinical and economic perspectives, and to assess this drug's public health impact. Weight reduction by current antiobesity drugs, compared to placebo, is at most around 5 kg. Orlistat, the most studied antiobesity drug, is associated with the least-severe adverse effects, but compared with other drugs in its class it also delivers the most modest weight loss versus placebo (less than 3 kg). Orlistat appears to have a favorable risk/benefit profile, and cost-effectiveness ratios seem to be within a range that is generally considered acceptable. In the short-term, orlistat is related to reduced diabetes incidence and to slightly improved blood pressure and lipid profiles. Long-term clinical effects have been largely unstudied, however, and this study did not find reports that considered mortality as an endpoint. Given a very low continuation with orlistat treatment in the population and very modest and, apparently, only short-term clinical effects, orlistat is not likely to have a significant impact on the population health. Public health approaches of improving environmental and social factors to foster healthier food choices and increase physical activity remain essential for addressing the obesity epidemic.

Effect of diet-induced weight loss on plasma apelin and cytokine levels in individuals with the metabolic syndrome

BACKGROUND AND AIMS

Adipose tissue is an active endocrine organ that secretes signaling molecules involved in the regulation of insulin sensitivity, food intake and inflammation. Apelin is a peptide secreted by adipose tissue that has been shown to modulate cardiovascular tone in animals. The aim of this study was to measure abdominal fat, blood pressure and circulating apelin, adiponectin, leptin, ghrelin, TNF-alpha and IL-6 levels in patients with the metabolic syndrome after a diet-induced weight loss.

METHODS AND RESULTS

35 obese individuals with the metabolic syndrome underwent an 8-week very-low-calorie diet (VLCD) and a 6-month weight maintenance period (WM) with 120mg orlistat or placebo administered 3 times daily. VLCD and WM (-15.1+/-1.0kg) decreased mean arterial pressure (MAP), insulin, leptin, triglycerides and visceral and subcutaneous adipose tissue. Moreover, adiponectin increased in response to the weight loss. However, the overall changes in plasma apelin, TNF-alpha and IL-6 were non-significant. A correlation between plasma apelin and TNF-alpha was observed at baseline (0.41, p<0.05), and the minor changes in plasma apelin levels were associated with changes in BMI during VLCD and MAP and TNF-alpha during VLCD and WM periods.

CONCLUSION

Despite reductions in BMI, body adiposity, MAP and enhancement of glucose metabolism and adiponectin in response to weight loss, no significant changes in plasma apelin, TNF-alpha and IL-6 were observed. However, apelin significantly correlated with TNF-alpha and MAP. These results suggest that apelin may not be that strongly correlated with the fat mass as an adipokine like the more abundant adipokines adiponectin or leptin and it might be involved in the regulation of inflammation and cardiovascular tone.

The use of sibutramine in the management of obesity and related disorders: an update

Aims:

To review the major trials that evaluated the efficacy and safety of the use of sibutramine for weight loss and the impact of this agent on obesity-related disorders.

Methods and results:

The most important articles on sibutramine up to January 2009 were located by a PubMed and Medline search. Sibutramine reduces food intake and body weight more than placebo and has positive effects on the lipid profile (mainly triglycerides and high density lipoprotein cholesterol), glycemic control and inflammatory markers in studies for up to one year. Preliminary studies showed that sibutramine may also improve other obesity-associated disorders such as polycystic ovary syndrome, left ventricular hypertrophy, binge eating disorder and adolescent obesity. The high discontinuation rates and some safety issues mainly due to the increase in blood pressure and pulse rate have to be considered. Additionally, it has not yet been established that treatment with sibutramine will reduce cardiovascular events and total mortality.

Conclusions:

Sibutramine, in conjunction with lifestyle measures, is a useful drug for reducing body weight and improving associated cardiometabolic risk factors and obesity-related disorders. Studies of longer duration are required to determine the precise indications of the drug, to evaluate safety issues and to assess its efficacy on cardiovascular mortality.

Current pharmacotherapeutic concepts for the treatment of obesity in adults

Obesity is one of the greatest public health challenges of the twenty-first century. The World Health Organization (WHO) reports that in 2005 approximately 1.6 billion adults were overweight and at least 400 million adults were obese. The prevalence of obesity is still continuing to increase dramatically. Overweight and obese people carry a higher risk for a variety of cardiovascular diseases including hypertension, coronary heart disease, stroke and peripheral occlusive artery disease. Weight loss is considered to be the initial step which helps to prevent or to control the clinical consequences of obesity. In a great number of patients who are not able to reduce weight by means of non-pharmacological measures, drug therapy can assist in reaching the weight management targets. Drug treatment should only be considered as part of a systematic weight management program including dietary and lifestyle changes. This review summarizes current pharmacotherapeutic concepts for the treatment of obesity in adults focusing on efficacy and safety of anti-obesity drugs.

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.