Obesity--is it a genetic disorder?

The Interplay of UCP3 and PCSK1 Variants in Severe Obesity

Obesity is a heterogeneous and multifactorial disease with a strong genetic component. While polygenic obesity accounts for most common cases, rare monogenic variants contribute, particularly in severe, early-onset obesity. Among the lesser-studied candidates are UCP3 and PCSK1, genes involved in key metabolic pathways. RECENT FINDINGS: The UCP3 p.Val192Ile (c.574G > A) and PCSK1 p.Asn221Asp (c.661 A > G) variants have been independently associated with metabolic pathways, including fatty acid oxidation and hormone processing, as well as a modestly increased risk of obesity. Clinical and genetic characterization of two patients with severe early-onset obesity revealed the co-occurrence of these variants, which were associated with metabolic disturbances such as insulin resistance. PURPOSE OF THE REVIEW: This narrative review examined the functional and clinical significance of UCP3 and PCSK1 variants in severe obesity, presenting two case reports to illustrate their potential impact. Our findings support a potential model in which rare variants in distinct metabolic genes may interact synergistically to exacerbate disease severity. Further studies are needed to elucidate their combined functional effects and contributions to obesity pathogenesis.

Postgenomic understandings of fatness and metabolism

'Obesity' has, for decades, been a subject of intense scientific and public interest, and remains a key target for postgenomic science. I examine the emergence of determinism in research into 'obesity' in the postgenomic field of metabolomics. I argue that determinism appears in metabolomics research in two ways: firstly, fragmentation and narrow construal of the environment is evident in metabolomics studies on weight loss interventions, resulting in particular features of the environment (notably, dietary intake) having outsized influence while the wider social environment is neglected. Secondly, studies aiming to characterize the metabolic signature of 'obesity' are guided by a commitment to a deterministic connection between 'obesity' and dysfunction, leading to a neglect or distortion of metabolic heterogeneity across individuals regardless of body size.

Disease: An ill-founded concept at odds with the principle of patient-centred medicine

BACKGROUND

Despite the at least decades long record of philosophical recognition and interest, the intricacy of the deceptively familiar appearing concepts of 'disease', 'disorder', 'disability', and so forth, has only recently begun showing itself with clarity in the popular discourse wherein its newly emerging prominence stems from the liberties and restrictions contingent upon it. Whether a person is deemed to be afflicted by a disease or a disorder governs their ability to access health care, be it free at the point of use or provided by an insurer; it also influences the treatment of individuals by the judicial system and employers; it even affects one's own perception of self.

AIMS

All existing philosophical definitions of disease struggle with coherency, causing much confusion and strife, and leading to inconsistencies in real-world practice. Hence, there is a real need for an alternative.

MATERIALS AND METHODS

In the present article I analyse the variety of contemporary views of disease, showing them all to be inadequate and lacking in firm philosophical foundations, and failing to meet the desideratum of patient-driven care.

RESULTS

Illuminated by the insights emanating from the said analysis, I introduce a novel approach with firm ethical foundations, which foundations are rooted in sentience, that is the subjective experience of sentient beings.

DISCUSSION

I argue that the notion of disease is at best superfluous, and likely even harmful in the provision of compassionate and patient-centred care.

CONCLUSION

Using a series of presently contentious cases illustrate the power of the proposed framework which is capable of providing actionable and humane solutions to problems that leave the current theories confounded.

Allostatic load in early adolescence: gene / environment contributions and relevance for mental health

Background

Allostatic load is the cumulative "wear and tear" on the body due to chronic adversity. We aimed to test poly-environmental (exposomic) and polygenic contributions to allostatic load and their combined contribution to early adolescent mental health.

Methods

We analyzed data on N = 5,035 diverse youth (mean age 12) from the Adolescent Brain Cognitive Development Study (ABCD). Using dimensionality reduction method, we calculated and overall allostatic load score (AL) using body mass index [BMI], waist circumference, blood pressure, blood glycemia, blood cholesterol, and salivary DHEA. Childhood exposomic risk was quantified using multi-level environmental exposures before age 11. Genetic risk was quantified using polygenic risk scores (PRS) for metabolic system susceptibility (type 2 diabetes [T2D]) and stress-related psychiatric disease (major depressive disorder [MDD]). We used linear mixed effects models to test main, additive, and interactive effects of exposomic and polygenic risk (independent variables) on AL (dependent variable). Mediation models tested the mediating role of AL on the pathway from exposomic and polygenic risk to youth mental health. Models adjusted for demographics and genetic principal components.

Results

We observed disparities in AL with non-Hispanic White youth having significantly lower AL compared to Hispanic and Non-Hispanic Black youth. In the diverse sample, childhood exposomic burden was associated with AL in adolescence (beta=0.25, 95%CI 0.22-0.29, P<.001). In European ancestry participants (n=2,928), polygenic risk of both T2D and depression was associated with AL (T2D-PRS beta=0.11, 95%CI 0.07-0.14, P<.001; MDD-PRS beta=0.05, 95%CI 0.02-0.09, P=.003). Both polygenic scores showed significant interaction with exposomic risk such that, with greater polygenic risk, the association between exposome and AL was stronger. AL partly mediated the pathway to youth mental health from exposomic risk and from MDD-PRS, and fully mediated the pathway from T2D-PRS.

Conclusions

AL can be quantified in youth using anthropometric and biological measures and is mapped to exposomic and polygenic risk. Main and interactive environmental and genetic effects support a diathesis-stress model. Findings suggest that both environmental and genetic risk be considered when modeling stress-related health conditions.

Integrated bioinformatics and statistical approach to identify the common molecular mechanisms of obesity that are linked to the development of two psychiatric disorders: Schizophrenia and major depressive disorder

Obesity is a chronic multifactorial disease characterized by the accumulation of body fat and serves as a gateway to a number of metabolic-related diseases. Epidemiologic data indicate that Obesity is acting as a risk factor for neuro-psychiatric disorders such as schizophrenia, major depression disorder and vice versa. However, how obesity may biologically interact with neurodevelopmental or neurological psychiatric conditions influenced by hereditary, environmental, and other factors is entirely unknown. To address this issue, we have developed a pipeline that integrates bioinformatics and statistical approaches such as transcriptomic analysis to identify differentially expressed genes (DEGs) and molecular mechanisms in patients with psychiatric disorders that are also common in obese patients. Biomarker genes expressed in schizophrenia, major depression, and obesity have been used to demonstrate such relationships depending on the previous research studies. The highly expressed genes identify commonly altered signalling pathways, gene ontology pathways, and gene-disease associations across disorders. The proposed method identified 163 significant genes and 134 significant pathways shared between obesity and schizophrenia. Similarly, there are 247 significant genes and 65 significant pathways that are shared by obesity and major depressive disorder. These genes and pathways increase the likelihood that psychiatric disorders and obesity are pathogenic. Thus, this study may help in the development of a restorative approach that will ameliorate the bidirectional relation between obesity and psychiatric disorder. Finally, we also validated our findings using genome-wide association study (GWAS) and whole-genome sequence (WGS) data from SCZ, MDD, and OBE. We confirmed the likely involvement of four significant genes both in transcriptomic and GWAS/WGS data. Moreover, we have performed co-expression cluster analysis of the transcriptomic data and compared it with the results of transcriptomic differential expression analysis and GWAS/WGS.

Association between meal frequency with anthropometric measures and blood pressure in Iranian children and adolescents

BACKGROUND

This study aimed to assess the association of meal frequency with anthropometric measures and blood pressure in Iranian children and adolescents.

METHODS

In this national survey, 14,880 students with 6-18 years of age were selected by stratified multistage sampling method from urban and rural regions of 30 provinces of Iran. Meal frequency was assessed by a questionnaire prepared based on global school-based student health survey. Physical measurements included height, weight, waist circumference, systolic blood pressure (SBP), and diastolic blood pressure (DBP).

RESULTS

The participation rate was 90.6% including 49.24% girls and 75.5% urban residents. Skipping breakfast and dinner were more frequent in girls than in boys (71.6% vs. 64.1%, 91.2% vs. 86.9%, respectively, P<0.05). Overweight, obesity, and abdominal obesity were more prevalent in those who had two meals, one meal, or very low intake (P<0.001) than those had three meals. There were no significant differences in SBP, DBP, and blood pressure across to different meal frequency groups (P>0.05). Students who had very low intake and one meal per week had a higher risk of abdominal obesity compared with those who had three meals (OR 1.7, 95% CI: 1.3-2.3, and OR 1.6, 95% CI: 1.4-2.0, respectively).

CONCLUSIONS

An inverse significant association between higher meal frequency and anthropometric indices was observed. Therefore, encouraging children and adolescents for regular meal intake should be considered as a health priority in the pediatric population.

Investigation of associations of European, African, Amerindian genomic ancestries and MC4R, FTO, FAIM2, BDNF loci with obesity-related traits in Rio de Janeiro, Brazil

A complex web of causation is involved in adiposity, including environmental, social and genetic factors. We aimed to investigate associations between genetic factors such as ancestry and single nucleotide polymorphisms, and obesity-related traits in a sampled Brazilian population. A sample of 501 unrelated adults participating in 2013 at the longitudinal Pró-Saúde Study (EPS) in Rio de Janeiro, Brazil was selected. We analysed 46 AIM-InDels (insertion/deletion) as genetic ancestry markers and four single nucleotide polymorphisms located in the genes MC4R (rs17782313), FTO (rs9939609), FAIM2 (rs7138803) and BDNF (rs4074134), previously described as associated with obesity. The selected obesity-related markers were anthropometric parameters such as body mass index, waist circumference and waist-to-hip ratio, and body composition measurements namely body fat percentage, android fat mass and gynoid fat mass. The sample showed greater European ancestry (57.20%), followed by African (28.80%) and lastly Amerindian (14%). Our results suggest that the rs4074134 (BDNF) CC genotype was directly associated with gynoid fat mass, whereas body fat percentage, android fat mass and the anthropometric parameters seem not to be associated with neither ancestry nor the four polymorphisms in this population sample, most likely due to a stronger role of social, behavioural and environmental determinants.

The Influence of the Differentiation of Genes Encoding Peroxisome Proliferator-Activated Receptors and Their Coactivators on Nutrient and Energy Metabolism

Genetic components may play an important role in the regulation of nutrient and energy metabolism. In the presence of specific genetic variants, metabolic dysregulation may occur, especially in relation to the processes of digestion, assimilation, and the physiological utilization of nutrients supplied to the body, as well as the regulation of various metabolic pathways and the balance of metabolic changes, which may consequently affect the effectiveness of applied reduction diets and weight loss after training. There are many well-documented studies showing that the presence of certain polymorphic variants in some genes can be associated with specific changes in nutrient and energy metabolism, and consequently, with more or less desirable effects of applied caloric reduction and/or exercise intervention. This systematic review focused on the role of genes encoding peroxisome proliferator-activated receptors (PPARs) and their coactivators in nutrient and energy metabolism. The literature review prepared showed that there is a link between the presence of specific alleles described at different polymorphic points in PPAR genes and various human body characteristics that are crucial for the efficacy of nutritional and/or exercise interventions. Genetic analysis can be a valuable element that complements the work of a dietitian or trainer, allowing for the planning of a personalized diet or training that makes the best use of the innate metabolic characteristics of the person who is the subject of their interventions.

The Multifunctional Role of Herbal Products in the Management of Diabetes and Obesity: A Comprehensive Review

Obesity and diabetes are the most demanding health problems today, and their prevalence, as well as comorbidities, is on the rise all over the world. As time goes on, both are becoming big issues that have a big impact on people's lives. Diabetes is a metabolic and endocrine illness set apart by hyperglycemia and glucose narrow-mindedness because of insulin opposition. Heftiness is a typical, complex, and developing overall wellbeing worry that has for quite some time been connected to significant medical issues in individuals, all things considered. Because of the wide variety and low adverse effects, herbal products are an important hotspot for drug development. Synthetic compounds are not structurally diverse and lack drug-likeness properties. Thus, it is basic to keep on exploring herbal products as possible wellsprings of novel drugs. We conducted this review of the literature by searching Scopus, Science Direct, Elsevier, PubMed, and Web of Science databases. From 1990 until October 2021, research reports, review articles, and original research articles in English are presented. It provides top to bottom data and an examination of plant-inferred compounds that might be utilized against heftiness or potentially hostile to diabetes treatments. Our expanded comprehension of the systems of activity of phytogenic compounds, as an extra examination, could prompt the advancement of remedial methodologies for metabolic diseases. In clinical trials, a huge number of these food kinds or restorative plants, as well as their bioactive compounds, have been shown to be beneficial in the treatment of obesity.

A Pilot Study of Gene Expression Analysis in Peripheral Blood Mononuclear Cells in Response to a Hypocaloric Mediterranean Diet

Background

Few studies have examined gene expression in peripheral blood mononuclear cells (PBMCs) after a dietary intervention.

Objective

Our study is aimed at evaluating in a pilot study the peripheral blood gene expression in obese patients after weight loss secondary to a hypocaloric Mediterranean diet.

Design

A sample of 11 obese subjects without metabolic syndrome was enrolled. Biochemical, anthropometric parameters and microarray analysis were performed at baseline and after 6 months of dietary intervention.

Results

The mean age was 43.1 ± 6.3 years, and the mean body mass index (BMI) was 38.6 ± 8.1 kg/m². All the next improvements were statistically significant: body weight −7.4 ± 1.9 kg, BMI -2.5 ± 0.2 kg, fat mass −5.7 ± 1.2 kg, waist circumference −5.8 ± 1.2 cm, triglycerides −17.4 ± 6.5 mg/dl, C-reactive protein −3.1 ± 1.5 mg/dL, insulin −2.1 ± 1.0 mUI/L, and HOMA-IR −0.7 ± 0.2 units. We identified 634 differentially expressed genes: 262 genes with relative higher expression levels and 372 with lower expression levels. Cluster analysis showed 35 genes in nutritional disease and 17 genes in endocrine system. The most relevant gene was thyroid peroxidase (TPO), and this gene was overexpressed, and the next genes carbonic anhydrase VI (CA6), caveolin protein 1 (CAV1) and solute carrier family type 12 (SLLC12A3), soluble carrier family type 12 (SLLC12A3), beta 3 receptor (ADRB3), and glutamate receptor ionotropic N methyl D aspartate 2 A (GRIN2A) were all underexpressed.

Conclusion

In PBMC from obese patients after a diet with a Mediterranean pattern, the expression of 634 genes, of the endocrine system and of nutritional disease, is modified.

Obesity risk is associated with altered cerebral glucose metabolism and decreased μ-opioid and CB1 receptor availability

BACKGROUND

Obesity is a pressing public health concern worldwide. Novel pharmacological means are urgently needed to combat the increase of obesity and accompanying type 2 diabetes (T2D). Although fully established obesity is associated with neuromolecular alterations and insulin resistance in the brain, potential obesity-promoting mechanisms in the central nervous system have remained elusive. In this triple-tracer positron emission tomography study, we investigated whether brain insulin signaling, μ-opioid receptors (MORs) and cannabinoid CB₁ receptors (CB₁Rs) are associated with risk for developing obesity.

METHODS

Subjects were 41 young non-obese males with variable obesity risk profiles. Obesity risk was assessed by subjects' physical exercise habits, body mass index and familial risk factors, including parental obesity and T2D. Brain glucose uptake was quantified with [¹⁸F]FDG during hyperinsulinemic euglycemic clamp, MORs were quantified with [¹¹C]carfentanil and CB₁Rs with [¹⁸F]FMPEP-d₂.

RESULTS

Subjects with higher obesity risk had globally increased insulin-stimulated brain glucose uptake (19 high-risk subjects versus 19 low-risk subjects), and familial obesity risk factors were associated with increased brain glucose uptake (38 subjects) but decreased availability of MORs (41 subjects) and CB₁Rs (36 subjects).

CONCLUSIONS

These results suggest that the hereditary mechanisms promoting obesity may be partly mediated via insulin, opioid and endocannabinoid messaging systems in the brain.

Challenges in tackling energy expenditure as obesity therapy: From preclinical models to clinical application

BACKGROUND

A chronic imbalance of energy intake and energy expenditure results in excess fat storage. The obesity often caused by this overweight is detrimental to the health of millions of people. Understanding both sides of the energy balance equation and their counter-regulatory mechanisms is critical to the development of effective therapies to treat this epidemic.

SCOPE OF REVIEW

Behaviors surrounding ingestion have been reviewed extensively. This review focuses more specifically on energy expenditure regarding bodyweight control, with a particular emphasis on the organs and attractive metabolic processes known to reduce bodyweight. Moreover, previous and current attempts at anti-obesity strategies focusing on energy expenditure are highlighted. Precise measurements of energy expenditure, which consist of cellular, animal, and human models, as well as measurements of their translatability, are required to provide the most effective therapies.

MAJOR CONCLUSIONS

A precise understanding of the components surrounding energy expenditure, including tailored approaches based on genetic, biomarker, or physical characteristics, must be integrated into future anti-obesity treatments. Further comprehensive investigations are required to define suitable treatments, especially because the complex nature of the human perspective remains poorly understood.

Interaction of multiple risk factors and population attributable fraction for type 2 diabetes and hypertension among adults aged 15-49 years in Northeast India

AIMS

The aim is to assess the association and population attributable fraction (PAF) of multiple risk factors combination for diabetes and hypertension among adults in the Northeast region of India.

METHODS

Data used is from the Indian Demographic Health Survey conducted in 2015-16. The study comprised 107, 766 respondents (95,153 females and 12, 613 males) aged 15-49 years. We examined four modifiable risk factors: smoking, alcohol consumption, aerated drinks consumption, and overweight or obesity. PAF was calculated using the relative risk from the multivariable logistic regression models.

RESULTS

Overweight or obesity in conjunction with smoking was associated with 43.9 % of patients with diabetes. Smoking in conjunction with alcohol and overweight or obesity contributed to 53% of patients with diabetes (PAF = 53 %). The three risk factors combination (i.e., smoking, alcohol, and overweight or obesity) is associated with the most hypertension cases (PAF = 50.7 %). Experiencing all four risk factors is associated with 50.3 % of patients with hypertension. In women, the four-risk combination contributed the most hypertension cases (PAF = 46.8 %).

CONCLUSIONS

Overweight or obesity was the single most significant factor leading to hypertension and diabetes among the study population. Also, smoking, alcohol, and overweight or obesity together are prominent risk factors for hypertension and diabetes.

Association of the MC4R rs17782313 polymorphism with plasma ghrelin, leptin, IL6 and TNFα concentrations, food intake and eating behaviors in morbidly obese women

PURPOSE

The rs17782313 variant of the MC4R gene plays an important role in the obesity phenotype. Studies that evaluate environmental factors and genetic variants associated with obesity may represent a great advance in understanding the development of this disease. This work seeks to assess the association of the polymorphism of MC4R rs17782313 on plasma parameters, including leptin, ghrelin, tumor necrosis factor (TNFα) and interleukin 6 (IL6), and on the eating behaviors of morbidly obese women.

METHODS

70 adult women with BMI between 40 and 60 kg/m² were recruited. Laboratory and anthropometric data were recorded. Using a visual analog scale (VAS), the feelings of hunger and satiety were evaluated. The presence or absence of binge eating was evaluated through the Binge Eating Scale (BES) questionnaire. Habitual food intake was analyzed using 3-day dietary records. TaqMan^® assays were conducted using real-time PCR to assess genotype polymorphism variants from peripheral blood DNA.

RESULTS

This study found that female patients with the MC4R rs17782313 polymorphism had high levels of ghrelin and reduced levels of IL6 in the postprandial period. We observed a higher prevalence of severe binge eating in more than 50% of women with at least one risk allele.

CONCLUSION

Our hypothesis is that the MC4R rs17782313 polymorphism may influence the release of ghrelin, even without being associated with feelings of hunger and satiety. More than half of women with this polymorphism exhibited severe binge eating.

LEVEL OF EVIDENCE

Level III: case-control analytic study.

The Effectiveness of Supportive Psychotherapy in Weight Loss in a Group of Young Overweight and Obese Women

Overweight and obesity are among the most widespread health problems worldwide. The primary cause of obesity is an inability to control overeating. Therefore, today, obesity needs to be treated more as an eating disorder, i.e., a mental disorder, and thus, it should be approached as such. Taking the above together, this study aimed to assess the impact of supportive psychotherapy on reducing body weight in young overweight and obese women who attempted slimming therapy and, additionally, the possibility of maintaining the weight-loss effect in the long term. Sixty young women aged 20–30 were randomized into three groups that differed in therapeutic management. With the help of an individually selected diet plan, the highest effectiveness in weight loss was demonstrated in people whose weight reduction was supported by goal-oriented psychotherapy. In this group, a sustained effect of slimming and even further weight loss were observed six months following the discontinuation of the therapy. In conclusion, traditional slimming therapies using an individual diet plan and a dietitian’s care are effective; however, supportive psychotherapeutic work provides more beneficial results and maintains the change from a long-term perspective.

Sandwich ELISA-Based Electrochemical Biosensor for Leptin in Control and Diet-Induced Obesity Mouse Model

Leptin is a peptide hormone produced primarily in adipose tissues. Leptin is considered a biomarker associated with obesity and obesity-mediated diseases. Biosensor detection of leptin in the blood may play a critical role as an indicator of dynamic pathological changes. In this paper, we introduce an electrochemical biosensor that adopts o-Phenylenediamine (oPD) on screen-printed gold electrodes (SPGEs) for detecting the leptin from a mouse model of diet-induced obesity (DIO). A linear calibration curve for the leptin concentration was obtained in the ranges from 0.1 to 20 ng/mL with a lower detection limit of 0.033 ng/mL. The leptin concentration was quantified with HRP (horseradish peroxidase)-catalyzed oxidation of oPD by two voltammetry methods: cyclic voltammetry (CV) and square-wave voltammetry (SWV). The proposed sandwich enzyme-linked immunosorbent assay (ELISA)-based electrochemical biosensor for the leptin in mouse blood serum showed high stability, sensitivity, selectivity, and effectivity compared to the commercial Leptin ELISA measurement. Thus, we believe that this leptin biosensor can be a sensitive analytical tool to detect low-levels of biomarkers in clinics and point-of-care testing (POCT).

Addressing the heterogeneity in liver diseases using biological networks

The abnormalities in human metabolism have been implicated in the progression of several complex human diseases, including certain cancers. Hence, deciphering the underlying molecular mechanisms associated with metabolic reprogramming in a disease state can greatly assist in elucidating the disease aetiology. An invaluable tool for establishing connections between global metabolic reprogramming and disease development is the genome-scale metabolic model (GEM). Here, we review recent work on the reconstruction of cell/tissue-type and cancer-specific GEMs and their use in identifying metabolic changes occurring in response to liver disease development, stratification of the heterogeneous disease population and discovery of novel drug targets and biomarkers. We also discuss how GEMs can be integrated with other biological networks for generating more comprehensive cell/tissue models. In addition, we review the various biological network analyses that have been employed for the development of efficient treatment strategies. Finally, we present three case studies in which independent studies converged on conclusions underlying liver disease.

Effects of a high protein/low carbohydrate low-calorie diet versus a standard low-calorie diet on anthropometric parameters and cardiovascular risk factors, role of polymorphism rs3123554 in the cannabinoid receptor gene type 2 (CB2R)

BACKGROUND

CB2R receptors has been referred to as the peripheral cannabinoid receptor isoform, and regulate inflammatory response in various settings. CB2R gene variants could play a role on metabolic changes after weight loss with different interventions.

OBJECTIVE

To assess the effect of the genetic variant (rs3123554) of the CB2R gene on anthropometric and biochemical changes after weight loss secondary to a high protein/low carbohydrate diet vs. a standard low-calorie diet during 9 months.

DESIGN

268 obese subjects were randomly allocated to one of two diets for 9 months, Diet HP (high protein-low carbohydrate low-calorie diet) and Diet S (standard protein low-calorie diet). Biochemical and anthropometric parameters were measured at baseline and at 3 and 9 months.

RESULTS

Ninety-four patients (35.1%) had genotype GG and 174 (64.9%) subjects had the following genotypes; GA (115 patients, 42.9%) or AA (59 study subjects, 18.0%) (second group). After both diets, body mass index (BMI), fat mass, weight, waist circumference, and systolic blood pressure improved in both genotypes with no difference between diets. Before and after both low-calorie diets, body weight, BMI, fat mass, and waist circumference were higher in A allele carriers than in non-A allele carriers. After both diets (HP and S), levels of glucose, insulin, HOMA-IR, triglycerides, total cholesterol, and LDL cholesterol decreased in non-A allele carriers. These parameters remained unchanged in A allele carriers. Leptin levels decreased after HP and S diets in both genotypes.

CONCLUSION

Non-A allele carriers showed a better response of total cholesterol, LDL cholesterol, triglycerides, glucose, HOMA-IR, and insulin levels than allele A carriers with both low-calorie diets and with the same weight loss.

Association of FTO and ADRB2 gene variation with energy restriction induced adaptations in resting energy expenditure and physical activity

Background

Energy restriction induces adaptations in resting energy expenditure (REE) and physical activity; inter-individual variability could be ascribed to genetic predisposition.The aim was to examine if changes in REE and physical activity as a result of weight loss were affected by candidate single nucleotide polymorphisms (SNPs).

Methods

148 subjects (39 men, 109 women), mean ± SD age: 41 ± 9 year; body mass index (BMI): 31.9 ± 3.0 kg/m², followed a very low energy diet for 8 weeks. SNPs were selected from six candidate genes: ADRB2, FTO, MC4R, PPARG2, PPARD and PPARGC1A. REE (ventilated hood) and physical activity (tri-axial accelerometer) were assessed before and after the diet. General linear modelling included gender, age and additional relevant covariates for all parameters.

Results

The heterozygotic genotype of FTO was associated with a higher amount of physical activity (1.71 Mcounts/d; CI 1.62-1.81) compared to the homozygotic major genotype (1.50 Mcounts/d; CI 1.40-1.59) (P < 0.001) while the homozygotic risk allele genotype was not different (1.56 Mcounts/d; CI 1.39-1.74) at baseline; moreover, a similar pattern was observed after energy restriction. Carrying the homozygotic minor genotype of ADRB2 was associated with a larger decrease in REE (P < 0.05) and greater adaptive thermogenesis (P < 0.05) after weight loss.

Conclusion

Carrying the minor ADRB2 allele homozygous was associated with a larger diet induced metabolic adaptation in energy expenditure and suggest a central role for reduced lipid mobilization. Carrying the risk allele of FTO homozygous was not associated with lower physical activity at baseline or after weight loss. Heterozygous carriers of one FTO risk allele showed greater physical activity before and after weight loss which might protect them in part from the higher obesity risk associated with FTO.

Polymorphism rs3123554 in the cannabinoid receptor type 2 (CB2R) gene is associated to metabolic changes after biliopancreatic diversion surgery

INTRODUCTION

The role of genetic variants of the CB2R gene in weight loss after a dietary intervention has been investigated in few studies, none of which has been conducted after bariatric surgery.

OBJECTIVES

The aim of this study was to assess the effect of the genetic variant (rs3123554) of the CB2R gene on cardiovascular risk factors and weight loss secondary to a biliopancreatic diversion.

DESIGN

The study simple consisted of 147 patients with morbid obesity. Biochemical and anthropometric parameters were measured at baseline and at each visit during 3 years (1, 2, and 3 years).

RESULTS

Percent excess weight loss, body mass index, weight, waist circumference, fat mass, blood pressure, fasting glucose, LDL cholesterol, total cholesterol, insulin, HOMA-IR, and triglyceride levels improved in both genotype groups. Decreases in fasting insulin levels and HOMA-IR were higher in non-A allele carriers as compared to A allele carriers.

CONCLUSIONS

Our data suggest that patients with morbid obesity who undergo bariatric surgery and carry the A allele of variant rs3123554 of the CB2R gene have greater weight. This allele has no influence on weight loss after surgery, but results in a lower decrease in insulin levels and insulin resistance.

Common polymorphism in the cannabinoid receptor gene type 2 (CB2R) rs3123554 are associated with metabolic changes after two different hypocaloric diets with different dietary fatty profiles

BACKGROUND

The role of CB2R gene variants on weight loss after a dietary intervention has been investigated in few studies.

OBJECTIVE

We evaluate the effect of this genetic variant (rs3123554) of CB2R gene on cardiovascular risk factors and weight loss secondary to high monounsaturated fat vs a high polyunsaturated fat hypocaloric diets.

DESIGN

A Caucasian population of 362 obese patients was enrolled. Patients were randomly allocated during 3 months to one of two diets (Diet P high polyunsaturated (PUFAs) fat hypocaloric diet vs, Diet M high monounsaturated (MUFAs) fat hypocaloric diet).

RESULTS

In both genotype groups (GG vs GA+AA), body weight, body mass index (BMI), fat mass, waist circumference and systolic blood pressure decreased after diet P and M. Body weight, BMI, fat mass and waist circumference were higher in A allele carriers than non A allele carriers. The improvement of these parameters was higher in non A allele carriers than A allele carriers. In non A allele carriers with both diets, the decrease of total cholesterol, LDL-cholesterol, insulin and HOMA-IR was higher than A allele carriers after both diets. After diet P, triglyceride levels decrease in non A allele carriers.

CONCLUSION

Our data suggest that carriers of the minor allele of rs3123554 variant of CB2R gene lose less body weight during to different hypocaloric diets with different fatty acid. Moreover, non A-allele carriers showed a better response of LDL-cholesterol, HOMA-IR and insulin levels than A-carriers with both hypocaloric diets.

Effects of polymorphism rs3123554 in the cannabinoid receptor gene type 2 (CB2R) on metabolic and adiposity parameters after weight loss with two hypocaloric diets

BACKGROUND

The role of CB2R gene variants on weight loss after a dietary intervention remained unclear.

OBJECTIVE

Our aim was to analyze the effects of rs3123554 of CB2R receptor gene on metabolic and adiposity parameters after two different hypocaloric diets in obese subjects.

DESIGN

A Caucasian population of 280 obese patients was enrolled. Patients were randomly allocated during 3 months to one of two diets (Diet I - moderate in carbohydrate. Vs Diet II - normal in carbohydrate).

RESULTS

In both genotype groups (GG vs GA + AA), body weight, body mass index (BMI), fat mass, waist circumference and systolic blood pressure decreased after diet I and II. The decrease of these parameters was higher in non A allele carriers than A allele carriers. Pre- and post-dietary intervention, body weight, BMI, fat mass and waist circumference were higher in A allele carriers than non A allele carriers. In non A allele carriers, the decrease of glucose, insulin, HOMA-IR and Interleukin-6 levels was higher than A allele carriers after both diets.

CONCLUSION

Carriers of the minor allele of rs3123554 variant of CB2R gene loose less body weight during two different hypocaloric diets. The improvement of metabolic parameters was better in no A allele carriers than A allele carriers.

RS 10767664 gene variant in Brain Derived Neurotrophic Factor (BDNF) affect metabolic changes and insulin resistance after a standard hypocaloric diet

BACKGROUND

Role of BDNF variants on change in body weight and cardiovascular risk factors after weight loss remains unclear in obese patients.

OBJECTIVE

Our aim was to analyze the effects of rs10767664 BDNF gene polymorphism on body weight, cardiovascular risk factors and serum adipokine levels after a standard hypocaloric diet in obese subjects.

DESIGN

A Caucasian population of 80 obese patients was analyzed before and after 3months on a standard hypocaloric diet.

RESULTS

Fifty patients (62.5%) had the genotype AA and 30 (37.5%) subjects had the next genotypes; AT (25 patients, 31.3%) or TT (5 study subjects, 6.3%) (second group). In non T allele carriers, the decreases in weight-3.4±2.9kg (T allele group -1.7±2.0kg:p=0.01), BMI -1.5±0.2kg (T allele group -1.2±0.5kg:p=0.02), fat mass-2.3±1.1kg (T allele group -1.7±0.9kg:p=0.009), waist circumference-3.8±2.4cm (T allele group -2.1±3.1cm:p=0.008), triglycerides -13.2±7.5mg/dl (T allele group +2.8±1.2mg/dl:p=0.02), insulin -2.1±1.9mUI/L (T allele group -0.3±1.0mUI/L:p=0.01), HOMA-IR -0.9±0.4 (T allele group -0.1±0.8:p=0.01) and leptin -10.1±9.5ng/dl (T allele group -3.1±0.2ng/dl:p=0.01) were higher than T allele carriers.

CONCLUSION

rs10767664 variant of BDNF gene modify anthropometric and biochemical changes after weight loss with a hypocaloric diet.

Cardiovascular Risk Factors and Insulin Resistance after Two Hypocaloric Diets with Different Fat Distribution in Obese Subjects: Effect of the rs10767664 Gene Variant in Brain-Derived Neurotrophic Factor

BACKGROUND

The role of brain-derived neurotrophic factor (BDNF) variants on change in body weight and cardiovascular risk factors after weight loss remains unclear in obese patients.

OBJECTIVE

Our aim was to analyze the effects of the rs10767664 BDNF gene polymorphism on body weight, cardiovascular risk factors, and serum adipokine levels after a high monounsaturated fatty acids (MUFAs) hypocaloric diet (diet M) versus a high polyunsaturated fatty acids (PUFAs) hypocaloric diet (diet P).

METHODS

A Caucasian population of 361 obese patients was enrolled. Subjects who met the inclusion criteria were randomly allocated to one of two diets for a period of 3 months.

RESULTS

Two hundred and sixteen subjects (59.8%) had the genotype AA (wild-type group), and 145 (40.2%) patients had the genotypes AT (122 patients, 33.8%) or TT (23 patients, 6.4%) (mutant-type group). After weight loss with diet P and diet M and in both genotype groups, body mass index, weight, fat mass, waist circumference, systolic blood pressure, serum leptin levels, low-density lipoprotein cholesterol, and total cholesterol decreased in a significant way. Secondary to weight loss with diet M and only in the wild-type group, insulin levels (-2.1 ± 2.0 vs. -0.7 ± 2.9 IU/L, p < 0.05) and homeostatic model assessment of insulin resistance (-0.7 ± 0.9 vs. -0.3 ± 1.0 U, p < 0.05) decreased.

CONCLUSION

Our data show that the rs10767664 variant of the BDNF gene modifies insulin resistance and insulin levels after weight loss with a hypocaloric diet enriched with MUFAs.

MC4R variant rs17782313 and manifestation of obese phenotype in Pakistani females

MC4R represents a key player involved in melanocortin-mediated control of energy balance. Recently identified near MC4R variant rs17782313 (T > C) can serve as a contributing factor for obese phenotype but its association with obesity has never been sought in a sample of the Pakistani population. The role of genetic variants as causal factors varies across populations. Association studies in a specific population can help us to distinguish global from local gene–gene and gene–environment interactions. This is the first study that investigated the association of rs17782313 with obesity and various obesity-linked anthropometric, metabolic, physical, and behavioural traits in Pakistani subjects including 306 OW/OB (overweight and obese) and 300 NW (normal weight) individuals. The comparison of various aforementioned obesity-linked continuous and categorical variables between OW/OB and NW subjects revealed that almost all variables were found significantly aberrant (p < 0.05) in OW/OB subjects as compared to their age- and gender-matched NW controls indicating greater risk of developing various cardio-metabolic disorders. The genotyping of rs17782313 showed significant association of this variant with obesity and obesity-linked anthropometric traits in females suggesting the gender-specific effect of this variant in our population. The minor allele C increased the risk of obesity by 1.55 times (95% CI = 1.1–2.18, p = 0.01) whereas homozygous CC genotype increased the risk by 2.43 times (95% CI = 1.19–4.96, p = 0.015) in females. However, no association of rs17782313 was observed with any of the obesity-linked metabolic, physical, and behavioural traits except random eating timings. In conclusion, the current study significantly contributes to the knowledge of the genetic proneness to obesity in Pakistani females. This could also be helpful for forthcoming meta-analysis studies elucidating which variants are truly associated with the susceptibility to develop an obese phenotype.

The current study significantly contributes to the knowledge of the genetic proneness to obesity in Pakistani females and could also be helpful for forthcoming meta-analysis studies.

The future of nutrition: Nutrigenomics and nutrigenetics in obesity and cardiovascular diseases

Over time, the relationship between diet and health has aroused great interest, since nutrition can prevent and treat several diseases. It has been demonstrated that general recommendations on macronutrients and micronutrients do not affect to every individual in the same way because diet is an important environmental factor that interacts with genes. Thus, there is a growing necessity of improving a personalized nutrition to treat obesity and associated medical conditions, taking into account the interactions between diet, genes and health. Therefore, the knowledge of the interactions between the genome and nutrients at the molecular level, has led to the advent of nutritional genomics, which involves the sciences of nutrigenomics and nutrigenetics. In this review, we will comprehensively analyze the role of the most important genes associated with two interrelated chronic medical conditions, such as obesity and cardiovascular diseases.

Epigenetic Regulation of Adipokines

Adipose tissue expansion in obesity leads to changes in the expression of adipokines, adipocyte-specific hormones that can regulate whole body energy metabolism. Epigenetic regulation of gene expression is a mechanism by which cells can alter gene expression through the modifications of DNA and histones. Epigenetic mechanisms, such as DNA methylation and histone modifications, are intimately tied to energy metabolism due to their dependence on metabolic intermediates such as S-adenosylmethionine and acetyl-CoA. Altered expression of adipokines in obesity may be due to epigenetic changes. The goal of this review is to highlight current knowledge of epigenetic regulation of adipokines.

rs10767664 Gene Variant in Brain-Derived Neurotrophic Factor Is Associated with Diabetes Mellitus Type 2 in Caucasian Females with Obesity

BACKGROUND

The role of brain-derived neurotrophic factor (BDNF) variants on diabetes prevalence, basal adipokine levels, body weight, and cardiovascular risk factors remains unclear in obese patients.

OBJECTIVE

This study is aimed at analyzing the effects of rs10767664 BDNF gene polymorphism on diabetes mellitus prevalence, body weight, cardiovascular risk factors, and serum adipokine levels in obese female patients.

DESIGN

A total of 507 obese women were enrolled in a prospective way. Biochemical evaluation and anthropometric measures were recorded.

RESULTS

The frequency of diabetes mellitus in the group of patients with non-T allele was 20.1 and 28.3% in T-allele carriers. Logistic regression showed a risk of diabetes mellitus of 1.33 (95% CI 1.17-2.08) in subjects with T allele adjusted by age and body mass index (BMI). T-allele carriers with diabetes mellitus have a higher weight, BMI, waist circumference, blood pressure, glucose, homeostasis model assessment insulin resistance (HOMA-IR), insulin, and C-reactive protein (CRP) levels than non-T-allele carriers.

CONCLUSION

rs10767664 polymorphism of BDNF gene is associated with prevalence of diabetes mellitus in obese female patients. T-allele carriers with diabetes mellitus have a higher weight, fat mass, blood pressure, level of insulin, glucose, HOMA-IR, and CRP than non-T-allele carriers.

Does neighbourhood deprivation affect the genetic influence on body mass?

Most research into the role of gene-environment interactions in the etiology of obesity has taken environment to mean behaviours such as exercise and diet. While interesting, this is somewhat at odds with research into the social determinants of obesity, in which the focus has shifted away from individuals and behaviours to the types of wider obesogenic environments in which individuals live, which influence and produce these behaviours. This study combines these two strands of research by investigating how the genetic influence on body mass index (BMI), used as a proxy for obesity, changes across different neighbourhood environments measured by levels of deprivation. Genetics are incorporated using a classical twin design with data from Twins UK, a longitudinal study of UK twins running since 1992. A multilevel modelling approach is taken to decompose variation between individuals into genetic, shared environmental, and non-shared environmental components. Neighbourhood deprivation is found to be a statistically significant predictor of BMI after conditioning on individual characteristics, and a heritability of 0.75 is estimated for the entire sample. This heritability estimate is shown, however, to be higher in more deprived neighbourhoods and lower in less deprived ones, and this relationship is statistically significant. While this research cannot say anything directly about the mechanisms behind the relationship, it does highlight how the relative importance of genetic factors can vary across different social environments, and therefore the value of considering both genetic and social determinants of health simultaneously.

Interaction between Pro12Ala polymorphism of PPARγ2 and diet on adiposity phenotypes

The aim of this report is to perform a systematic review and qualitative synthesis of the literature to address whether, and to what extent, diet modulates the effects of the Pro12Ala polymorphism of peroxisome proliferator-activated receptor gamma 2 (PPARγ2) on body weight and other measures of adiposity. A systematic search of the literature was conducted, wherein both observational and experimental studies of adults were reviewed. Overall, the results of the observational studies show little consistency. Methodological differences in their design, conduct and analysis may largely account for the apparently discrepant findings. This notwithstanding, the main picture that emerges is that the energy content and composition of the diet may affect BMI, body composition and metabolic parameters in Ala allele carriers more than in Pro/Pro homozygotes. In most studies, carriers of the Ala allele with an obesogenic lifestyle (i.e. high-energy, high-carbohydrate and, to some extent, high-fat diets) are more obese than Pro homozygotes. Well-designed intervention studies with a sufficiently large sample size consistently show that carriers of the Ala allele are more prone to weight loss when exposed to a healthy lifestyle; however, these individuals do not seem to retain these benefits when returning to a sedentary lifestyle and inadequate dieting behaviours. Some key questions in this area of research have emerged. Carefully designed and adequately powered studies are needed, particularly involving the development and validation of standardized tools for the assessment of dietary exposure, including the use of biomarkers, to move the field forward.

The influence of parental participation on obesity interventions in african american adolescent females: an integrative review

African American adolescent females have the highest prevalence rates of obesity among those age 18 and under. The long-term health effects and associated comorbidities of obesity within this cohort threaten the health and well-being of a major section of the U.S. population. There is a need to understand the influence of parental support in reducing obesity related health disparities. Using a social ecological framework to explore parental influence on adolescent obesity interventions allows for greater insight into the complex and dynamic influences affecting the lives of African American adolescent females who are obese.

Association of pediatric obesity and migraine with comparison to tension headache and samples from other countries

The link between body weight and headache has hardly been examined in children. The aim was to evaluate the association of obesity and migraine in selected pediatric patients and compare the findings with the literature. Data on clinical symptoms, headache type, and body mass index standard deviation score were derived from the medical files of 245 patients with migraine and 87 with tension headache. Comparison of the 3 subgroups of migraine patients of normal weight, overweight, and obese with the corresponding body mass index standard deviation score subgroups of patients with tension-type headache yielded no statistically significant differences in frequency of headache attacks per month, or duration of headache attacks in hours. These results call into question earlier reports linking headache and obesity in children. Differences in findings between our study and those in the literature highlight several factors that should be addressed in further studies. A larger sample size may reveal more significant results.

Gene polymorphisms and increased DNA damage in morbidly obese women

Obesity is characterized by increased adipose tissue mass resulting from a chronic imbalance between energy intake and expenditure. Furthermore, there is a clearly defined relationship among fat mass expansion, chronic low-grade systemic inflammation and reactive oxygen species (ROS) generation; leading to ROS-related pathological events. In the past years, genome-wide association studies have generated convincing evidence associating genetic variation at multiple regions of the genome with traits that reflect obesity. Therefore, the present study aimed to evaluate the relationships among the gene polymorphisms ghrelin (GHRL-rs26802), ghrelin receptor (GHSR-rs572169), leptin (LEP-rs7799039), leptin receptor (LEPR-rs1137101) and fat mass and obesity-associated (FTO-rs9939609) and obesity. The relationships among these gene variants and the amount of DNA damage were also investigated. Three hundred Caucasian morbidly obese and 300 eutrophic (controls) women were recruited. In summary, the results demonstrated that the frequencies of the GHRL, GHSR, LEP and LEPR polymorphisms were not different between Brazilian white morbidly obese and eutrophic women. Exceptions were the AA-FTO genotype and allele A, which were significantly more frequent in obese women than in the controls (0.23% vs. 0.10%; 0.46 vs. 0.36, respectively), and the TT-FTO genotype and the T allele, which were less frequent in morbidly obese women (p<0.01). Furthermore, significant differences in the amount of genetic lesions associated with FTO variants were observed only in obese women. In conclusion, this study demonstrated that the analyzed SNPs were not closely associated with morbid obesity, suggesting they are not the major contributors to obesity. Therefore, our data indicated that these gene variants are not good biomarkers for predicting risk susceptibility for obesity, whereas ROS generated by the inflammatory status might be one of the causes of DNA damage in obese women, favoring genetically related diseases as obesity comorbidities.

DNA methylation of leptin and adiponectin promoters in children is reduced by the combined presence of obesity and insulin resistance

OBJECTIVE

Epigenetic alterations have been suggested to be associated with obesity and related metabolic disorders. Here we examined the correlation between obesity and insulin resistance with the methylation frequency of the leptin (LEP) and adiponectin (ADIPOQ) promoters in obese adolescents with the aim to identify epigenetic markers that might be used as tools to predict and follow up the physiological alterations associated with the development of the metabolic syndrome.

SUBJECTS

One hundred and six adolescents were recruited and classified according to body mass index and homeostasis model of assessment-insulin resistance index. The circulating concentrations of leptin, adiponectin and of several metabolic markers of obesity and insulin resistance were determined by standard methods. The methylation frequency of the LEP and ADIPOQ promoters was determined by methylation-specific PCR (MS-PCR) in DNA obtained from peripheral blood samples.

RESULTS

Obese adolescents without insulin resistance showed higher and lower circulating levels of, respectively, leptin and adiponectin along with increased plasmatic concentrations of insulin and triglycerides. They also exhibited the same methylation frequency than lean subjects of the CpG sites located at -51 and -31 nt relative to the transcription start site of the LEP gene. However, the methylation frequency of these nucleotides dropped markedly in obese adolescents with insulin resistance. We found the same inverse relationship between the combined presence of obesity and insulin resistance and the methylation frequency of the CpG site located at -283 nt relative to the start site of the ADIPOQ promoter.

CONCLUSIONS

These observations sustain the hypothesis that epigenetic modifications might underpin the development of obesity and related metabolic disorders. They also validate the use of blood leukocytes and MS-PCR as a reliable and affordable methodology for the identification of epigenetic modifications that could be used as molecular markers to predict and follow up the physiological changes associated with obesity and insulin resistance.

Is the gene-environment interaction paradigm relevant to genome-wide studies? The case of education and body mass index

This study uses data from the Framingham Heart Study to examine the relevance of the gene-environment interaction paradigm for genome-wide association studies (GWAS). We use completed college education as our environmental measure and estimate the interactive effect of genotype and education on body mass index (BMI) using 260,402 single-nucleotide polymorphisms (SNPs). Our results highlight the sensitivity of parameter estimates obtained from GWAS models and the difficulty of framing genome-wide results using the existing gene-environment interaction typology. We argue that SNP-environment interactions across the human genome are not likely to provide consistent evidence regarding genetic influences on health that differ by environment. Nevertheless, genome-wide data contain rich information about individual respondents, and we demonstrate the utility of this type of data. We highlight the fact that GWAS is just one use of genome-wide data, and we encourage demographers to develop methods that incorporate this vast amount of information from respondents into their analyses.

Use of quantile regression to investigate the longitudinal association between physical activity and body mass index

OBJECTIVE

To examine associations among age, physical activity (PA), and birth cohort on body mass index (BMI) percentiles in men.

METHODS

Longitudinal analyses using quantile regression were conducted among men with ≥ two examinations between 1970 and 2006 from the Aerobics Center Longitudinal Study (n = 17,759). Height and weight were measured; men reported their PA and were categorized as inactive, moderately, or highly active at each visit. Analyses allowed for longitudinal changes in PA.

RESULTS

BMI was greater in older than younger men and in those born in 1960 than those born in 1940. Inactive men gained weight significantly more rapidly than active men. At the 10th percentile, increases in BMI among inactive, moderately active, and highly active men were 0.092, 0.078, and 0.069 kg/m(2) per year of age, respectively. The 10th percentile increased by 0.081 kg/m(2) per birth year and by 0.180 kg/m(2) at the 90th percentile, controlling for age.

CONCLUSION

Although BMI increased with age, PA reduced the magnitude of the gradient among active compared to inactive men. Regular PA had an important, protective effect against weight gain. This study provides evidence of the utility of quantile regression to examine the specific causes of the obesity epidemic.

Etiology of Obesity Over the Life Span: Ecological and Genetic Highlights from Asian Countries

Obesity is a worldwide pandemic, and the prevalence rate has doubled since the 1980s. Asian countries are also experiencing the global epidemic of obesity with its related health consequences. The prevalence of overweight and obesity are increasing at an alarming rate across all age groups in Asia. These increases are mainly attributed to rapid economic growth, which leads to socio-economic, nutrition and lifestyle transitions, resulting in a positive energy balance. In addition, fat mass and obesity-associated gene variants, copy number variants in chromosomes and epigenetic modifications have shown positive associations with the risk of obesity among Asians. In this review highlights of prevalence and related ecological and genetic factors that could influence the rapid rise in obesity among Asian populations are discussed.

Obesity and chronic stress are able to desynchronize the temporal pattern of serum levels of leptin and triglycerides

Disruption of the circadian system can lead to metabolic dysfunction as a response to environmental alterations. This study assessed the effects of the association between obesity and chronic stress on the temporal pattern of serum levels of adipogenic markers and corticosterone in rats. We evaluated weekly weight, delta weight, Lee index, and weight fractions of adipose tissue (mesenteric, MAT; subcutaneous, SAT; and pericardial, PAT) to control for hypercaloric diet-induced obesity model efficacy. Wistar rats were divided into four groups: standard chow (C), hypercaloric diet (HD), stress plus standard chow (S), and stress plus hypercaloric diet (SHD), and analyzed at three time points: ZT0, ZT12, and ZT18. Stressed animals were subjected to chronic stress for 1h per day, 5 days per week, during 80 days. The chronic exposure to a hypercaloric diet was an effective model for the induction of obesity and metabolic syndrome, increasing delta weight, Lee index, weight fractions of adipose tissue, and triglycerides and leptin levels. We confirmed the presence of a temporal pattern in the release of triglycerides, corticosterone, leptin, and adiponectin in naïve animals. Chronic stress reduced delta weight, MAT weight, and levels of triglycerides, total cholesterol, and leptin. There were interactions between chronic stress and obesity and serum total cholesterol levels, between time points and obesity and adiponectin and corticosterone levels, and between time points and chronic stress and serum leptin levels. In conclusion, both parameters were able to desynchronize the temporal pattern of leptin and triglyceride release, which could contribute to the development of metabolic diseases such as obesity and metabolic syndrome.

Social Inequalities in Obesity Persist in the Nordic Region Despite Its Relative Affluence and Equity

Social inequalities in overweight and obesity (OWOB) have persisted in the affluent and reputedly egalitarian Nordic countries. In this review we examine associations between socioeconomic position (SEP) and OWOB, and secular trends in such associations. Determinants and possible causes of the relations are discussed together with opportunities to cope with OWOB as a public health problem. The findings show a persisting inverse social gradient. An interaction between SEP and gender is noted for adults in Denmark, Finland and Iceland and for children in Sweden. There are overall tendencies for increased inequality, however no consistent trend for an increased social gradient in OWOB. Reasons that increased inequality does not unequivocally mirror in a steepened social gradient in obesity may include methodological questions as well as societal efforts to counteract obesity. Multi-level efforts are needed to prevent OWOB.

Methodological framework: discovering foods or nutrients with a causative influence on body weight in free-living settings

A significant increase in food availability has been implicated in the worldwide obesity epidemic, and there is significant interest in understanding if specific foods may contribute to weight gain or aid in weight loss. Many foods have been studied in controlled laboratory studies or short-term studies, and these findings are often the basis for food-based public health recommendations to reduce or prevent obesity. Unfortunately, often these findings are not applicable to free-living settings where many interacting factors influence energy balance and body weight. Therefore, a proposed set of evidence criteria for making a food-based public health recommendation to reduce or prevent obesity is outlined and discussed herein, to serve as a basis for future committee or panel discussion and formalization. Using these criteria as a basis for making strong evidence-based recommendations will improve the state of science and policy in this area.

Ghrelin at the interface of obesity and reward

The prevalence of obesity continues to increase and has reached epidemic proportions. Accumulating data over the past few decades have given us key insights and broadened our understanding of the peripheral and central regulation of energy homeostasis. Despite this, the currently available pharmacological treatments, reducing body weight, remain limited due to poor efficacy and side effects. The gastric peptide ghrelin has been identified as the only orexigenic hormone from the periphery to act in the hypothalamus to stimulate food intake. Recently, a role for ghrelin and its receptor at the interface between homeostatic control of appetite and reward circuitries modulating the hedonic aspects of food has also emerged. Nonhomeostatic factors such as the rewarding and motivational value of food, which increase with food palatability and caloric content, can override homeostatic control of food intake. This nonhomeostatic decision to eat leads to overconsumption beyond nutritional needs and is being recognized as a key component in the underlying causes for the increase in obesity incidence worldwide. In addition, the hedonic feeding behavior has been linked to food addiction and an important role for ghrelin in the development of addiction has been suggested. Moreover, plasma ghrelin levels are responsive to conditions of stress, and recent evidence has implicated ghrelin in stress-induced food-reward behavior. The prominent role of the ghrelinergic system in the regulation of feeding gives rise to it as an effective target for the development of successful antiobesity pharmacotherapies that not only affect satiety but also selectively modulate the rewarding properties of food and reduce the desire to eat.

Oral leptin treatment in suckling rats ameliorates detrimental effects in hypothalamic structure and function caused by maternal caloric restriction during gestation

A poor prenatal environment brings about perturbations in leptin surge and hypothalamic circuitry that program impaired ability to regulate energy homeostasis in adulthood. Here, using a rat model of moderate maternal caloric restriction during gestation, we aimed to investigate whether leptin supplementation with physiological doses throughout lactation is able to ameliorate the adverse developmental malprogramming effects exerted in offspring hypothalamus structure and function. Three groups of male and female rats were studied: the offspring of ad libitum fed dams (controls), the offspring of 20% calorie restricted dams during the first part of pregnancy (CR), and CR rats supplemented with physiological doses of leptin throughout lactation (CR-Leptin). Animals were sacrificed on postnatal day 25. Morphometric and immunohistochemical studies on arcuate (ARC) and paraventicular (PVN) nucleus were performed and hypothalamic expression levels of selected genes were determined. In CR males, leptin treatment restored, at least in part, the number of immunoreactive neuropeptide Y (NPY(+)) cells in ARC, the total number of cells in PVN, hypothalamic NPY, cocaine- and amphetamine-regulated transcript (CART) and suppressor of cytokine signalling-3 (SOCS-3) mRNA levels, and plasma leptin levels, which were decreased in CR animals. CR-Leptin males showed higher hypothalamic long-form leptin receptor (ObRb) mRNA levels, compared to control and CR animals. In CR females, leptin treatment reverted the increased number of cells in ARC and cell density in ARC and PVN, and reduced hypothalamic SOCS-3 mRNA expression to levels similar to controls. Leptin treatment also reverted the increased relative area of NPY(+) fibers in the PVN occurring in CR animals. In conclusion, leptin supplementation throughout lactation is able to revert, at least partly, most of the developmental effects on hypothalamic structure and function caused by moderate maternal caloric restriction during gestation, and hence making this metabolic malprogramming reversible to some extent.