Obesity management interventions: a review of the evidence

Caloric Restriction and Hypothalamic Leptin Gene Therapy Have Differential Effects on Energy Partitioning in Adult Female Rats

Dieting is a common but often ineffective long-term strategy for preventing weight gain. Similar to humans, adult rats exhibit progressive weight gain. The adipokine leptin regulates appetite and energy expenditure but hyperleptinemia is associated with leptin resistance. Here, we compared the effects of increasing leptin levels in the hypothalamus using gene therapy with conventional caloric restriction on weight gain, food consumption, serum leptin and adiponectin levels, white adipose tissue, marrow adipose tissue, and bone in nine-month-old female Sprague-Dawley rats. Rats (n = 16) were implanted with a cannula in the 3rd ventricle of the hypothalamus and injected with a recombinant adeno-associated virus, encoding the rat gene for leptin (rAAV-Lep), and maintained on standard rat chow for 18 weeks. A second group (n = 15) was calorically-restricted to match the weight of the rAAV-Lep group. Both approaches prevented weight gain, and no differences in bone were detected. However, calorically-restricted rats consumed 15% less food and had lower brown adipose tissue Ucp-1 mRNA expression than rAAV-Lep rats. Additionally, calorically-restricted rats had higher abdominal white adipose tissue mass, higher serum leptin and adiponectin levels, and higher marrow adiposity. Caloric restriction and hypothalamic leptin gene therapy, while equally effective in preventing weight gain, differ in their effects on energy intake, energy expenditure, adipokine levels, and body composition.

Developing dimensions for a multicomponent multidisciplinary approach to obesity management: a qualitative study

BACKGROUND

There have been consistent recommendations for multicomponent and multidisciplinary approaches for obesity management. However, there is no clear agreement on the components, disciplines or processes to be considered within such an approach. In this study, we explored multicomponent and multidisciplinary approaches through an examination of knowledge, skills, beliefs, and recommendations of stakeholders involved in obesity management. These stakeholders included researchers, practitioners, educators, and patients.

METHODS

We used qualitative action research methods, including convergent interviewing and observation, to assist the process of inquiry.

RESULTS

The consensus was that a multicomponent and multidisciplinary approach should be based on four central meta-components (patient, practitioner, process, and environmental factors), and specific components of these factors were identified. Psychologists, dieticians, exercise physiologists and general practitioners were nominated as key practitioners to be included.

CONCLUSIONS

A complex condition like obesity requires that multiple components be addressed, and that both patients and multiple disciplines are involved in developing solutions. Implementing cycles of continuous improvement to deal with complexity, instead of trying to control for it, offers an effective way to deal with complex, changing multisystem problems like obesity.

Development of a Weight Loss Mobile App Linked With an Accelerometer for Use in the Clinic: Usability, Acceptability, and Early Testing of its Impact on the Patient-Doctor Relationship

Background

Although complications of obesity are well acknowledged and managed by clinicians, management of obesity itself is often difficult, which leads to its underdiagnosis and undertreatment in hospital settings. However, tools that could improve the management of obesity, including self-monitoring, engagement with a social network, and open channels of communication between the patient and doctor, are limited in a clinic-based setting.

Objective

The objective of our study was to evaluate the usability and acceptability of a newly developed mobile app linked with an accelerometer and its early effects on patient-doctor relationships.

Methods

From September 2013 to February 2014, we developed a mobile app linked with an accelerometer as a supportive tool for a clinic-based weight loss program. The app used information from electronic health records and delivered tailored educational material. Personal goal setting, as well as monitoring of weight changes and physical activity combined with feedback, are key features of the app. We also incorporated an interactive message board for patients and doctors. During the period of March 2014 to May 2014, we tested our mobile app for 1 month in participants in a hospital clinic setting. We assessed the app’s usability and acceptability, as well as the patient-doctor relationship, via questionnaires and analysis of app usage data.

Results

We recruited 30 individuals (18 male and 12 female) for the study. The median number of log-ins per day was 1.21, with the most frequently requested item being setting goals, followed by track physical activities and view personal health status. Scales of the depth of the patient-doctor relationship decreased from 27.6 (SD 4.8) to 25.1 (SD 4.5) by a Wilcoxon signed rank test (P=.02).

Conclusions

A mobile phone app linked with an accelerometer for a clinic-based weight loss program is useful and acceptable for weight management but exhibited less favorable early effects on patient-doctor relationships.

Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss

Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin, n=7) or a control vector encoding green fluorescent protein (rAAV-GFP, n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (-4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (-80%), serum leptin (-77%), and serum IGF1 (-34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover.

The role of genes involved in lipolysis on weight loss program in overweight and obese individuals

The ability of obese people to reduce weight in the same treatment varied. Genetic make up as well as the behavioral changes are important for the successfulness of the program. One of the most proposed genetic variations that have been reported in many intervention studies was genes that control lipolysis process. This review summarizes studies that were done showing the influence of genetic polymorphisms in lipolysis pathway and weight loss in a weight loss treatment program. Some studies had shown that certain enzymes involved in this process were related to successfulness of weight loss program. Single Nucleotide Polymorphism (SNP) in PLIN (11482G>A) and ADRB3 (Trp64Arg) are the most studied polymorphisms that have effect on weight loss intervention. However, those studies were not conclusive because of limited number of subjects used and controversies in the results. Thus, replication and confirmation on the role of those genes in weight loss are important due to their potential to be used as predictors of the results of the program.

Development of an OP9 derived cell line as a robust model to rapidly study adipocyte differentiation

One hallmark of obesity is adipocyte hypertrophy and hyperplasia. To gain novel insights into adipose biology and therapeutics, there is a pressing need for a robust, rapid, and informative cell model of adipocyte differentiation for potential RNAi and drug screens. Current models are prohibitive for drug and RNAi screens due to a slow differentiation time course and resistance to transfection. We asked if we could create a rapid, robust model of adipogenesis to potentially enable rapid functional and obesity therapeutic screens. We generated the clonal population OP9-K, which differentiates rapidly and reproducibly, and displays classic adipocyte morphology: rounded cell shape, lipid accumulation, and coalescence of lipids into a large droplet. We further validate the OP9-K cells as an adipocyte model system by microarray analysis of the differentiating transcriptome. OP9-K differentiates via known adipogenic pathways, involving the transcriptional activation and repression of common adipose markers Plin1, Gata2, C/Ebpα and C/Ebpβ and biological pathways, such as lipid metabolism, PPARγ signaling, and osteogenesis. We implemented a method to quantify lipid accumulation using automated microscopy and tested the ability of our model to detect alterations in lipid accumulation by reducing levels of the known master adipogenic regulator Pparγ. We further utilized our model to query the effects of a novel obesity therapeutic target, the transcription factor SPI1. We determine that reduction in levels of Spi1 leads to an increase in lipid accumulation. We demonstrate rapid, robust differentiation and efficient transfectability of the OP9-K cell model of adipogenesis. Together with our microscopy based lipid accumulation assay, adipogenesis assays can be achieved in just four days' time. The results of this study can contribute to the development of rapid screens with the potential to deepen our understanding of adipose biology and efficiently test obesity therapeutics.

A randomised trial of a weight loss intervention for overweight and obese people diagnosed with coronary heart disease and/or type 2 diabetes

BACKGROUND

Weight reduction limits disease progression in obese people with coronary heart disease (CHD) and/or type 2 diabetes mellitus (T2DM).

PURPOSE

To test a 16-week group-based weight reduction intervention combining exercise, diet and behaviour change strategies aimed to increase self-efficacy (Healthy Eating and Exercise Lifestyle Program-HEELP) on weight, body mass index (BMI), waist circumference and exercise.

METHODS

Participants with CHD and/or T2DM and BMI between 27 to 39 kg/m(2) were randomised to HEELP (n=83) or usual care (n=65).

RESULTS

Participants were aged a mean 63.47 years (SD 8.9), male (58 %) and Caucasian (79 %). HEELP participants lost significantly more weight, BMI and waist circumference and exercised more days/week for a longer duration/week than usual care. Clinically significant weight loss (≥5 %) was more common in HEELP than usual care.

CONCLUSION

The HEELP resulted in weight loss and improved exercise behaviour in obese people with CHD and T2DM.

Effect of anti-obesity drug on cardiovascular risk factors: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Anti-obesity drugs are widely used to prevent the complications of obesity, however, the effects of anti-obesity drugs on cardiovascular risk factors are unclear at the present time. We carried out a comprehensively systematic review and meta-analysis to assess the effects of anti-obesity drugs on cardiovascular risk factors.

METHODOLOGY AND PRINCIPAL FINDINGS

We systematically searched Medline, EmBase, the Cochrane Central Register of Controlled Trials, reference lists of articles and proceedings of major meetings for relevant literatures. We included randomized placebo-controlled trials that reported the effects of anti-obesity drugs on cardiovascular risk factors compared to placebo. Overall, orlistat produced a reduction of 2.39 kg (95%CI-3.34 to -1.45) for weight, a reduction of 0.27 mmol/L (95%CI: -0.36 to -0.17) for total cholesterol, a reduction of 0.21 mmol/L (95%CI: -0.30 to -0.12) for LDL, a reduction of 0.12 mmol/L (95%CI: -0.20 to -0.04) for fasting glucose, 1.85 mmHg reduction (95%CI: -3.30 to -0.40) for SBP, and a reduction of 1.49 mmHg (95%CI: -2.39 to -0.58) for DBP. Sibutramine only showed effects on weight loss and triglycerides reduction with statistical significances. Rimonabant was associated with statistically significant effects on weight loss, SBP reduction and DBP reduction. No other significantly different effects were identified between anti-obesity therapy and placebo.

CONCLUSION/SIGNIFICANCE

We identified that anti-obesity therapy was associated with a decrease of weight regardless of the type of the drug. Orlistat and rimonabant could lead to an improvement on cardiovascular risk factors. However, Sibutramine may have a direct effect on cardiovascular risk factors.

Continued postnatal administration of resveratrol prevents diet-induced metabolic syndrome in rat offspring born growth restricted

OBJECTIVE

A prenatal hypoxic insult leading to intrauterine growth restriction (IUGR) increases the susceptibility to develop metabolic syndrome (MetS) later in life. Since resveratrol (Resv), the polyphenol produced by plants, exerts insulin-sensitizing effects, we tested whether Resv could prevent deleterious metabolic effects of being born IUGR.

RESEARCH DESIGN AND METHODS

Pregnant rats were exposed to either a normoxic (control; 21% O(2)) or a hypoxic (IUGR; 11.5% O(2)) environment during the last third of gestation. After weaning, male offspring were randomly assigned to receive either a high-fat (HF; 45% fat) diet or an HF diet with Resv (4 g/kg diet) for 9 weeks when various parameters of the MetS were measured.

RESULTS

Relative to normoxic controls, hypoxia-induced IUGR offspring developed a more severe MetS, including glucose intolerance and insulin resistance, increased intra-abdominal fat deposition and intra-abdominal adipocyte size, and increased plasma triacylglycerol (TG) and free fatty acids, as well as peripheral accumulation of TG, diacylglycerol, and ceramides. In only IUGR offspring, the administration of Resv reduced intra-abdominal fat deposition to levels comparable with controls, improved the plasma lipid profile, and reduced accumulation of TG and ceramides in the tissues. Moreover, Resv ameliorated insulin resistance and glucose intolerance as well as impaired Akt signaling in the liver and skeletal muscle of IUGR offspring and activated AMP-activated protein kinase, which likely contributed to improved metabolic parameters in Resv-treated IUGR rats.

CONCLUSIONS

Our results suggest that early, postnatal administration of Resv can improve the metabolic profile of HF-fed offspring born from pregnancies complicated by IUGR.

Depression scores predict adherence in a dietary weight loss intervention trial

BACKGROUND & AIMS

Depression has a complex association with cardiometabolic risk, both directly as an independent factor and indirectly through mediating effects on other risk factors such as BMI, diet, physical activity, and smoking. Since changes to many cardiometabolic risk factors involve behaviour change, the rise in depression prevalence as a major global health issue may present further challenges to long-term behaviour change to reduce such risk. This study investigated associations between depression scores and participation in a community-based weight management intervention trial.

METHODS

A group of 64 overweight (BMI > 27), otherwise healthy adults, were recruited and randomised to follow either their usual diet, or an isocaloric diet in which saturated fat was replaced with monounsaturated fat (MUFA), to a target of 50% total fat, by adding macadamia nuts to the diet. Subjects were assessed for depressive symptoms at baseline and at ten weeks using the Beck Depression Inventory (BDI-II). Both control and intervention groups received advice on National Guidelines for Physical Activity and adhered to the same protocol for food diary completion and trial consultations. Anthropometric and clinical measurements (cholesterol, inflammatory mediators) also were taken at baseline and 10 weeks.

RESULTS

During the recruitment phase, pre-existing diagnosed major depression was one of a range of reasons for initial exclusion of volunteers from the trial. Amongst enrolled participants, there was a significant correlation (R = -0.38, p < 0.05) between BDI-II scores at baseline and duration of participation in the trial. Subjects with a baseline BDI ≥10 (moderate to severe depression symptoms) were more likely to dropout of the trial before week 10 (p < 0.001). BDI-II scores in the intervention (MUFA) diet group decreased, but increased in the control group over the 10-week period. Univariate analysis of variance confirmed these observations (adjusted R(2) = 0.257, p = 0.01). Body weight remained static over the 10-week period in the intervention group, corresponding to a relative increase in the control group (adjusted R(2) = 0.097, p = 0.064).

CONCLUSIONS

Depression symptoms have the potential to affect enrolment in and adherence to dietbased risk reduction interventions, and may consequently influence the generalisability of such trials. Depression scores may therefore be useful for characterising, screening and allocating subjects to appropriate treatment pathways.

Identifying population subgroups at risk for underestimating weight health risks and overestimating physical activity health benefits

People may incorrectly perceive that their body weight or Physical Activity (PA) meets health recommendations; this provides an obstacle for change. In this study self-reported BMI and PA were assessed in relation to questions regarding perception of meeting weight and PA recommendations. Signal detection analysis was used to identify population subgroups. Study outcomes showed that 34.4 per cent of the 2535 adult participants underestimated weight health risks; low income, male participants who believed they were sufficiently active underestimated weight health risks the most (52.6%). A total of 23.7 per cent of participants overestimated PA health benefits; older age, low educated participants who did not believe their body weight was a health risk overestimated PA health benefits the most (58.3%). In conclusion, as weight and PA misperceptions are high, efforts are needed to reduce these misperceptions, so that behaviour change initiatives can be more effective.