Recent advances in obesity: genetics and beyond

Critical Correlation Between Obesity and Cardiovascular Diseases and Recent Advancements in Obesity

Scientific literature has investigated and well-documented the complex relationship between obesity and cardiovascular diseases. Obese people are much more likely to have atrial fibrillation, dyslipidemia, diabetes, and coronary artery disease, among other cardiovascular conditions. Additionally, obesity poses a severe risk for diseases like hypertension, heart failure, and atherosclerotic heart diseases, affecting various aspects relating to their underlying mechanisms, diagnosis, and clinical effects. This article summarizes recent developments in our understanding of and response to obesity. Pharmacotherapy, gut microbiome research, bariatric surgery, digital health solutions, behavioral interventions, and precision medicine are just a few of the fields in which these developments have been made. While liposuction offers a less invasive option for redistributing volume and getting positive results, bariatric surgery remains the most effective treatment for severe obesity. Emphasis is placed on the pathophysiological mechanisms that underlie the complex interactions between obesity and a number of diseases, such as atrial fibrillation, diabetes, hypertension, dyslipidemia, and coronary artery disease. The significance of lifestyle changes in reducing the cardiovascular risks associated with obesity, such as atrial fibrillation and heart disease, is emphasized. To improve overall cardiovascular health and achieve better clinical outcomes, obesity must be promptly identified and actively managed. Investigations into how the gut microbiome affects obesity, the creation of novel pharmacological treatments for appetite suppression and metabolic enhancement, improvements in bariatric surgery methods that emphasize patient success and safety, as well as creative digital health solutions and behavioral treatments, are some examples of emerging research fields. In addition, precision medicine approaches, including the modulation of the gut microbiome through dietary changes and supplements, hold great promise in combating obesity and its associated comorbidities and have the potential to revolutionize the management of obesity by tailoring treatments to the specific needs of individual patients.

Obesity in Children

Child obesity is widely prevalent, and general pediatricians play an important role in identifying and caring for patients with obesity. Appropriate evaluation and treatment require an understanding of the complex etiology of child obesity, its intergenerational transmission, and its epidemiologic trends, including racial/ethnic and socioeconomic disparities. The American Academy of Pediatrics has published screening, evaluation, and treatment guidelines based on the best available evidence. However, gaps in evidence remain, and implementation of evidence-based recommendations can be challenging. It is important to review optimal care in both the primary care and multidisciplinary weight management settings. This allows for timely evaluation and appropriate referrals, with the pediatrician playing a key role in advocating for patients at higher risk. There is also a role for larger-scale prevention and policy measures that would not only aid pediatricians in managing obesity but greatly benefit child health on a population scale.

The Relationship Between Paternal Preconception Obesity and Health Behaviors and Childhood Obesity: Protocol for a Systematic Review

Background

Childhood obesity is a global public health concern and is a priority for researchers and policy makers. To overcome the epidemic of obesity, influencing factors throughout the life span need to be addressed, including those in the preconception period. A better understanding of the association between paternal preconception factors and childhood obesity is important for public health interventions.

Objective

This systematic review will examine the relationship between paternal preconception obesity and health behaviors and their offspring’s overweight or obesity.

Methods

Peer-reviewed quantitative studies and grey literature that report associations between paternal preconception obesity and health behaviors—such as smoking, exercise, and eating habits—and childhood overweight and obesity will be identified through a computerized literature search in 7 databases. The quality of each study will be assessed using the Quality Assessment Tool for Quantitative Studies. Characteristics of the included studies will be reported, and relevant findings from each paternal preconception exposure will be narratively synthesized. This review will follow the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) 2020 guidelines.

Results

This systematic review is anticipated to begin in December 2021 and be completed by the end of August 2022.

Conclusions

This systematic review will contribute to a better understanding of the relationship between preconception paternal exposures and their offspring’s overweight or obesity. Findings will help support health professionals working with prospective parents to educate fathers on the benefits of improving their weight and health behaviors during the preconception period.

International Registered Report Identifier (IRRID)

PRR1-10.2196/31254

Metabolic and Molecular Subacute Effects of a Single Moderate-Intensity Exercise Bout, Performed in the Fasted State, in Obese Male Rats

Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment and prevention of obesity, and recent studies suggest that the beneficial effects of exercise can be potentiated by the fasting state, thus potentially promoting additional effects. Despite the significant number of studies showing results that corroborate such hypothesis, very few have evaluated the effects of fasted-state exercise in overweight/obese populations. Therefore, the aim of this study was to evaluate the subacute effects (12 h after conclusion) of a single moderate-intensity exercise bout, performed in either a fed or an 8 h fasted state, on serum profile, substrate-content and heat shock pathway–related muscle protein immunocontent in obese male rats. Methods: Male Wistar rats received a modified high-fat diet for 12 weeks to induce obesity and insulin resistance. The animals were allocated to four groups: fed rest (FER), fed exercise (FEE), fasted rest (FAR) and fasted exercise (FAE). The exercise protocol was a 30 min session on a treadmill, with an intensity of 60% of VO₂max. The duration of the fasting period was 8 h prior to the exercise session. After a 12 h recovery, the animals were killed and metabolic parameters of blood, liver, heart, gastrocnemius and soleus muscles were evaluated, as well as SIRT1 and HSP70 immunocontent in the muscles. Results: HFD induced obesity and insulin resistance. Soleus glycogen concentration decreased in the fasted groups and hepatic glycogen decreased in the fed exercise group. The combination of exercise and fasting promoted a decreased concentration of serum total cholesterol and triglycerides. In the heart, combination fasting plus exercise was able to decrease triglycerides to control levels. In the soleus muscle, both fasting and fasting plus exercise were able to decrease triglyceride concentrations. In addition, heat shock protein 70 and sirtuin 1 immunocontent increased after exercise in the gastrocnemius and soleus muscles. Conclusions: An acute bout of moderate intensity aerobic exercise, when realized in fasting, may induce, in obese rats with metabolic dysfunctions, beneficial adaptations to their health, such as better biochemical and molecular adaptations that last for at least 12 h. Considering the fact that overweight/obese populations present an increased risk of cardiovascular events/diseases, significant reductions in such plasma markers of lipid metabolism are an important achievement for these populations.

Effects of Tyrosine and Tryptophan Supplements on the Vital Indicators in Mice Differently Prone to Diet-Induced Obesity

We studied the effects of the addition of large neutral amino acids, such as tyrosine (Tyr) and tryptophan (Trp), in mice DBA/2J and tetrahybrid mice DBCB receiving a high-fat, high-carbohydrate diet (HFCD) for 65 days. The locomotor activity, anxiety, muscle tone, mass of internal organs, liver morphology, adipokines, cytokines, and biochemical indices of animals were assessed. The Tyr supplementation potentiated increased anxiety in EPM and contributed to a muscle tone increase, a decrease in the AST/ALT ratio, and an increase in protein anabolism in both mice strains. Tyr contributed to a decrease in liver fatty degeneration and ALT reduction only in DBCB that were sensitive to the development of obesity. The addition of Trp caused an increase in muscle tone and potentiated an increase in anxiety with age in animals of both genotypes. Trp had toxic effects on the livers of mice, which was manifested in increased fatty degeneration in DBCB, edema, and the appearance of micronuclei in DBA/2J. The main identified effects of Tyr on mice are considered in the light of its modulating effect on the dopamine neurotransmitter metabolism, while for the Trp supplement, effects were presumably associated with the synthesis of its toxic metabolites by representatives of the intestinal microflora.

High-fat diet increases the level of circulating Monocyte Chemoattractant Protein-1 in Wistar rats, independent of obesity

Introduction

Low-grade chronic inflammation has emerged as a key pathogenic link between high-fat diet (HFD)-induced obesity and the increased risk of chronic diseases. Evidence has shown that HFDs may induce inflammation in the central nervous system and peripheral tissues. Monocyte Chemoattractant Protein-1 (MCP-1) is a product of various cells that is known to be an inflammatory marker. This study investigated whether a HFD could induce obesity and increase the level of MCP-1 in Wistar rats.

Methods

The Wistar rats were randomized into two groups: normal diet (ND) and HFD (n = 12 per group). Both groups were fed for 8 and 16 weeks, thus dividing the rats into 4 arms: ND8, ND16, HFD8, and HFD16 (n = 6 per sub-group). Obesity in rats was measured using the Lee index. Blood samples were taken to measure the level of MCP-1.

Results

Our results showed that obesity did not occur in the group with a normal diet (ND8 and ND16). However, in the HFD group (HFD8 and HFD16), 4 of the 6 rats became obese. However, MCP-1 was significantly higher among non-obese rats in the HFD group compared with the ND group (p < 0.001).

Conclusion

HFDs have been shown to increase the risk of obesity. In addition, increases in circulating MCP-1 were significantly different between Wistar rats given a HFD compared with the ND group.

Exploring the Impact of Obesity on Skeletal Muscle Function in Older Age

Sarcopenia is of important clinical relevance for loss of independence in older adults. The prevalence of obesity in combination with sarcopenia ("sarcopenic-obesity") is increasing at a rapid rate. However, whilst the development of sarcopenia is understood to be multi-factorial and harmful to health, the role of obesity from a protective and damaging perspective on skeletal muscle in aging, is poorly understood. Specifically, the presence of obesity in older age may be accompanied by a greater volume of skeletal muscle mass in weight-bearing muscles compared with lean older individuals, despite impaired physical function and resistance to anabolic stimuli. Collectively, these findings support a potential paradox in which obesity may protect skeletal muscle mass in older age. One explanation for these paradoxical findings may be that the anabolic response to weight-bearing activity could be greater in obese vs. lean older individuals due to a larger mechanical stimulus, compensating for the heightened muscle anabolic resistance. However, it is likely that there is a complex interplay between muscle, adipose, and external influences in the aging process that are ultimately harmful to health in the long-term. This narrative briefly explores some of the potential mechanisms regulating changes in skeletal muscle mass and function in aging combined with obesity and the interplay with sarcopenia, with a particular focus on muscle morphology and the regulation of muscle proteostasis. In addition, whilst highly complex, we attempt to provide an updated summary for the role of obesity from a protective and damaging perspective on muscle mass and function in older age. We conclude with a brief discussion on treatment of sarcopenia and obesity and a summary of future directions for this research field.

Relationships of apelin concentration and APLN T-1860C polymorphism with obesity in Thai children

Background

Childhood obesity represents a serious global health crisis. Apelin and its receptor system are widely distributed throughout the central nervous system and have been demonstrated to serve a role modulating feeding behaviour and energy homeostasis. The purposes of this study were to examine apelin concentrations and anthropometric-cardiometabolic parameters in obese and non-obese children and to identify associations of APLN T-1860C and APLNR G212A polymorphisms with apelin levels and obesity among Thai children.

Methods

This case-control study included an analysis of 325 Thai children: 198 children with obesity and 127 healthy non-obese children. Anthropometric-cardiometabolic variables and apelin concentration were measured. Genotyping of APLN T-1860C and APLNR G212A was performed using the polymerase chain reaction-restriction fragment length polymorphism technique.

Results

The obese group had significantly lower apelin and HDL-C levels but significantly higher triglycerides and glucose (TyG) index values, TG/HDL-C ratio and TC/HDL-C ratio than the non-obese group (p < 0.01). Apelin level was negatively correlated with body size phenotypes and cardiometabolic parameters (p < 0.05). The APLN T-1860C polymorphism (OR = 4.39, 95% CI = 1.25–15.28) and apelin concentration (OR = 0.45, 95% CI = 0.23–0.92) were significantly associated with obesity among female children (p < 0.05) only, after adjusting for potential covariates. However, the APLNR G212A polymorphism showed no significant relationship with apelin concentration or obesity.

Conclusion

These findings in Thai children suggest that apelin concentrations are related to obesity and cardiometabolic parameters. Furthermore, the APLN T-1860C polymorphism may influence susceptibility to obesity among female children.

Parental PM2.5 Exposure-Promoted Development of Metabolic Syndrome in Offspring Is Associated With the Changes of Immune Microenvironment

Parental exposure to ambient fine particulate matter (PM2.5) has been associated with some of adverse health outcomes in offspring. The association between parental PM2.5 exposure and the development of metabolic syndrome (MetS) in offspring, and the effects of parental PM2.5 exposure on the susceptibility of offspring mice to PM2.5, has not been evaluated. The C57BL/6 parental mice (male and female mice) were exposed to filtered air (FA) or concentrated PM2.5 (PM) using Shanghai-METAS for a total of 16 weeks. At week 12 during the exposure, we allowed the parental male and female mice to breed offspring mice. The male offspring mice were divided into 4 groups and exposed to PM and FA again. The results showed that whether the parental mice were exposed to PM2.5 or not, the offspring mice exposure to PM2.5 appeared the elevation of blood pressure, insulin resistance, impairment of glucose tolerance, and dyslipidemia when compared to the offspring mice exposure to FA. More importantly, no matter what the offspring mice were exposed to, parental PM exposure overwhelmingly impacted the fasting blood insulin, homeostasis model assessment-insulin resistance, serous low-density lipoprotein cholesterol, and total cholesterol, splenic T helper cell 17 (Th17) and Treg cells, serous interleukin (IL)-17A, IL-6, and IL-10 in offspring mice. The results suggested that the parental exposure to air pollution might induce the development of MetS in offspring and might enhance the susceptibility of offspring to environmental hazards. The effects of parental PM exposure on offspring might be related to the changes of immune microenvironment.

Genetic markers and continuity of healthy metabolic status: Tehran cardio-metabolic genetic study (TCGS)

Obese individuals can be categorized as “healthy obese” (MHO) and “unhealthy obese” (MUO) based on the presence or absence of metabolic abnormality. This study sets out to assess potential genetic causes behind persistence of healthy metabolic status in individuals categorized as “healthy obese”. This study was conducted in the framework of the Tehran cardio-metabolic genetic study (TCGS). 766 MHO subjects at the start of the study followed up 15 years for occurrence of metabolic unhealthy status. These two groups (persistent MHO, MUO) were compared regarding the presence or absence of 16 single nucleotide polymorphisms (SNPs) identified as being associated with obesity phenotype in previous studies. We used logistic regression model for assessing the association between MHO/MUO with candidate SNPs. By the end of the follow up, 206 (27%) were categorized as the persistent MHO and 560 (73%) as MUO groups. Considering interaction effect between some SNP and sex, a sex stratification analysis was applied. When the analysis was performed by gender, rs1121980 associated with a decrease, and rs7903146 with an increase in the likelihood of persistent MHO individuals. Another analysis was separately performed on postmenopausal women from both groups; it showed that rs13107325 was associated with an increase in the likelihood of persistent MHO status in this subgroup of woman. In all cases, the markers had dominant inheritance. This findings suggest that the expression of some genetic markers are associated with persistence of healthy metabolic status, in female obese individuals.

Insights into the multifactorial causation of obesity by integrated genetic and epigenetic analysis

Obesity is a highly heritable multifactorial disease that places an enormous burden on human health. Its increasing prevalence and the concomitant-reduced life expectancy has intensified the search for new analytical methods that can reduce the knowledge gap between genetic susceptibility and functional consequences of the disease pathology. Although the influence of genetics and epigenetics has been studied independently in the past, there is increasing evidence that genetic variants interact with environmental factors through epigenetic regulation. This suggests that a combined analysis of genetic and epigenetic variation may be more effective in characterizing the obesity phenotype. To date, limited genome-wide integrative analyses have been performed. In this review, we provide an overview of the latest findings, advantages, and challenges and discuss future perspectives.

Changes in Body Composition and FTO Whole Blood DNA Methylation Among Japanese Women: A Randomized Clinical Trial of Weight-Loss Program

OBJECTIVE

DNA methylation is an epigenetic mechanism that regulates gene expression. The obesity-related (FTO) gene is the first gene found to be associated with fat mass and obesity. However, no studies have examined the relationship between weight-loss intervention effect and FTO methylation in obese individuals with whole blood DNA. The purpose of this study was to quantify FTO whole blood DNA methylation and investigate the relationship between body composition, exercise capacity, and blood parameters with a 6-month weight-loss program intervention.

PARTICIPANTS AND METHODS

Eighteen female participants (mean age, 50.6 ±12.1 years, body mass index (BMI), 33.5 ± 6.2 kg/m²) who completed a 6-month weight-loss program at the obesity outpatient department at the Health Science Center of Kansai Medical University Hospital from March 2017 to October 2018 were included in the analysis. Participants were randomized into a normal treatment group (NTG) and a group with additional resistance training (RTG). Body composition, exercise tolerance and metabolic index were measured in each participant. DNA methylation status in whole blood samples was determined using pyrosequencing. All measurements were taken during the first visit and at the 6-month post-intervention visit.

RESULTS

The methylation rate was significantly decreased in the NTG in CpG1 (p=0.011) and total value of CpG (p=0.011), whereas in the treatment group containing resistance training (RTG), CpG3 (p=0.038) was increased significantly. Furthermore, the independent factors that determine %CpG3 of RTG were visceral fat area change rate (%VFA) (β = -0.568, P = 0.007, R2 = 0.527) and resistance training (β = 0.517, P = 0.012, R2 = 0.527), which have been extracted.

CONCLUSION

A 6-month weight-loss program, including resistance training, may be associated with decreased visceral fat area changes and increased RTG CpG3 methylation changes. However, further replication studies with larger sample sizes are warranted to verify the findings of this study.

Intracutaneous Delivery of Gelatins Reduces Fat Accumulation in Subcutaneous Adipose Tissue

Subcutaneous adipose tissue (SAT) accumulation is a constitutional disorder resulting from metabolic syndrome. Although surgical and non-surgical methods for reducing SAT exist, patients remain non-compliant because of potential adverse effects and cost. In this study, we developed a new minimally-invasive approach to achieve SAT reduction, using a microneedle (MN) patch prepared from gelatin, which is capable of regulating fat metabolism. Four gelatin types were used: three derived from fish (SA-FG, GT-FG 220, and GT-FG 250), and one from swine (SM-PG 280). We applied gelatin-based MN patches five times over 4 weeks to rats with high-fat diet (HD)-induced obesity, and determined the resulting amount of SAT. We also investigated the histological features and determined the expression levels of fat metabolism-associated genes in SAT using hematoxylin and eosin staining and western blotting, respectively. SAT decreased following treatment with all four gelatin MN patches. Smaller adipocytes were observed in the regions treated with SA-FG, GT-FG 250, and SM-PG 280 MNs, demonstrating a decline in fat accumulation. The expression levels of fat metabolism-associated genes in the MN-treated SAT revealed that GT-FG 220 regulates fatty acid synthase (FASN) protein levels. These findings suggest that gelatin MN patches aid in decreasing the quantity of unwanted SAT by altering lipid metabolism and fat deposition.

Congenital Leptin Deficiency and Leptin Gene Missense Mutation Found in Two Colombian Sisters with Severe Obesity

Background: Congenital leptin deficiency is a recessive genetic disorder associated with severe early-onset obesity. It is caused by mutations in the leptin (LEP) gene, which encodes the protein product leptin. These mutations may cause nonsense-mediated mRNA decay, defective secretion or the phenomenon of biologically inactive leptin, but typically lead to an absence of circulating leptin, resulting in a rare type of monogenic extreme obesity with intense hyperphagia, and serious metabolic abnormalities. Methods: We present two severely obese sisters from Colombia, members of the same lineal consanguinity. Their serum leptin was measured by MicroELISA. DNA sequencing was performed on MiSeq equipment (Illumina) of a next-generation sequencing (NGS) panel involving genes related to severe obesity, including LEP. Results: Direct sequencing of the coding region of LEP gene in the sisters revealed a novel homozygous missense mutation in exon 3 [NM_002303.3], C350G>T [p.C117F]. Detailed information and clinical measurements of these sisters were also collected. Their serum leptin levels were undetectable despite their markedly elevated fat mass. Conclusions: The mutation of LEP, absence of detectable leptin, and the severe obesity found in these sisters provide the first evidence of monogenic leptin deficiency reported in the continents of North and South America.

A controlled study of an integrated prevention program for improving disordered eating and body image among Mexican university students: A 3-month follow-up

Obesity and eating disorders are currently two significant health problems in Mexico. The aim of this study was to examine the effects of an integrated prevention program on university students through an exploratory controlled study that targeted specific predisposing factors of disordered eating and obesity related to healthy eating, physical activity, body image satisfaction and perceived pressure to be thin. A total of 388 university students participated (264 females and 124 males) and were assigned either to an intervention condition or one of the two control conditions (study skills vs. nonintervention); each comprised of a total of eight workshops lasting 90 min. The program did not have any effect on the male students. In contrast, there was an interaction effect for time and group in thin-ideal internalization (η²  = 0.04) and in disordered eating attitudes/behaviours (η²  = 0.03); both showed improvements over time only among the female sample. Though, the effect size was insignificant, which means that the effectiveness of this integrated prevention program was limited. Integrated prevention approaches to eating and weight-related problems are still nascent in Mexico, and further research in this field is warranted so as to fine tune future prevention programs.

Biochemical and Physiological Parameters in Rats Fed with High-Fat Diet: The Protective Effect of Chronic Treatment with Purple Grape Juice (Bordo Variety)

High-fat-diet (HFD) has been related to metabolic and cardiovascular diseases. Consumption of grapes and their byproducts containing phenolic compounds has been reported due to the benefits they produce for human health. The purpose of this study was to investigate the antioxidant and protective effect of chronic intake of purple grape juice on certain biochemical and physiological changes promoted by the consumption of HFD. Forty male rats were randomly divided into four groups to receive standard or HFD diet and/or conventional (CGJ) or organic grape juice (OGJ) for three months. Dietary intake, body weight gain, cardiometabolic parameters, and serum lipoperoxidation were investigated. Results showed that consumption of CGJ and OGJ changed the pattern of food and drink intake of the animals. There was a reduction in the body weight of animals that consumed grape juices and an increase in the weight gain in HFD and OGJ rats. HFD increased abdominal fat and the abdominal fat/weight ratio, and both grape juices prevented these modifications. HFD increased hepatic enzymes levels (aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT)) and reduced urea. Purple grape juices prevented some of these changes. HFD enhanced lipid peroxidation (thiobarbituric acid reactive substances (TBARS)) in serum and CGJ and OGJ prevented this increase. The consumption of purple grape juice has the potential to prevent and ameliorate most of the alterations provoked by HFD, therefore regular intake of grape products could promote beneficial effects.

The rs9939609 polymorphism in the fat mass and obesity associated (FTO) gene is associated with obesity in Tunisian population

CONTEXT

Variations in the fat mass and obesity-associated gene (FTO) has been associated with obesity in many populations, but the results are conflicting.

OBJECTIVE

The aim of this study was to evaluate the effect of the rs9939609 polymorphism in the FTO gene on obesity risk and plasma leptin, adiponectin, insulin and lipid concentrations in Tunisians.

MATERIALS AND METHODS

Four hundred and ninety-four subjects with obesity and 334 non-obese participated in this study. The rs9939609 (T/A) genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Significant differences in genotype frequencies were observed between cases and controls. In the separate analysis by gender, the association between the AA genotype and obesity was statistically significant in women but not in men. After stratification by obesity class this association remains only with obesity class III.

DISCUSSION

Our study is in agreement with studies on Caucasian, Portuguese and Cebu Filipino populations where a gender-specific association was found between rs9939609 polymorphism and obesity. It is also in agreement with studies on Mexican, Spanish and European populations, where an association was found with obesity class III.

CONCLUSION

The rs9939609 polymorphism of FTO gene is associated with obesity, especially obesity class III in women.

A Genomewide Integrative Analysis of GWAS and eQTLs Data Identifies Multiple Genes and Gene Sets Associated with Obesity

To identify novel susceptibility genes and gene sets for obesity, we conducted a genomewide expression association analysis of obesity via integrating genomewide association study (GWAS) and expression quantitative trait loci (eQTLs) data. GWAS summary data of body mass index (BMI) and waist-to-hip ratio (WHR) was driven from a published study, totally involving 339,224 individuals. The eQTLs dataset (containing 927,753 eQTLs) was obtained from eQTLs meta-analysis of 5,311 subjects. Integrative analysis of GWAS and eQTLs data was conducted by SMR software. The SMR single gene analysis results were further subjected to gene set enrichment analysis (GSEA) for identifying obesity associated gene sets. A total of 13,311 annotated gene sets were analyzed in this study. SMR single gene analysis identified 20 BMI associated genes (TUFM, SPI1, APOB48R, etc.). Also 3 WHR associated genes were detected (CPEB4, WARS2, and L3MBTL3). The significant association between Chr16p11 and BMI was observed by GSEA (FDR adjusted p value = 0.040). The TGCTGCT, MIR-15A, MIR-16, MIR-15B, MIR-195, MIR-424, and MIR-497 (FDR adjusted p value = 0.049) gene set appeared to be linked with WHR. Our results provide novel clues for the genetic mechanism studies of obesity. This study also illustrated the good performance of SMR for susceptibility gene mapping.

Chemical and non-chemical stressors affecting childhood obesity: a systematic scoping review

Childhood obesity in the United States has doubled over the last three decades and currently affects 17% of children and adolescents. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stressors found in a child's environment and how these interactions affect a child's health and well-being. The objectives of this systematic scoping review were to (1) identify potential chemical stressors in the context of non-chemical stressors that impact childhood obesity; and, (2) summarize our observations for chemical and non-chemical stressors in regards to child-specific environments within a community setting. A review was conducted to identify chemical and non-chemical stressors related to childhood obesity for the childhood life stages ranging from prenatal to adolescence. Stressors were identified and grouped into domains: individual behaviors, family/household behaviors, community stressors, and chemical exposures. Stressors were related to the child and the child's everyday environments and used to characterize child health and well-being. This review suggests that the interactions of chemical and non-chemical stressors are important for understanding a child's overall health and well-being. By considering these relationships, the exposure science research community can better design and implement strategies to reduce childhood obesity.

Role of MicroRNA Regulation in Obesity-Associated Breast Cancer: Nutritional Perspectives

Breast cancer is the most common malignancy diagnosed in women, and the incidence of breast cancer is increasing every year. Obesity has been identified as one of the major risk factors for breast cancer progression. The mechanisms by which obesity contributes to breast cancer development is not yet understood; however, there are a few mechanisms counted as potential producers of breast cancer in obesity, including insulin resistance, chronic inflammation and inflammatory cytokines, adipokines, and sex hormones. Recent emerging evidence suggests that alterations in microRNA (miRNA) expressions are found in several diseases, including breast cancer and obesity; however, miRNA roles in obesity-linked breast cancer are beginning to unravel. miRNAs are thought to be potential noninvasive biomarkers for diagnosis and prognosis of cancer patients with comorbid conditions of obesity as well as therapeutic targets. Recent studies have evidenced that nutrients and other dietary factors protect against cancer and obesity through modulation of miRNA expressions. Herein, we summarize a comprehensive overview of up-to-date information related to miRNAs and their molecular targets involved in obesity-associated breast cancer. We also address the mechanisms by which dietary factors modulate miRNA expression and its protective roles in obesity-associated breast cancer. It is hoped that this review would provide new therapeutic strategies for the treatment of obesity-associated breast cancer to reduce the burden of breast cancer.

The genetic epidemiology of substance use disorder: A review

BACKGROUND

Substance use disorder (SUD) remains a significant public health issue. A greater understanding of how genes and environment interact to regulate phenotypes comprising SUD will facilitate directed treatments and prevention.

METHODS

The literature studying the neurobiological correlates of SUD with a focus on the genetic and environmental influences underlying these mechanisms was reviewed. Results from twin/family, human genetic association, gene-environment interaction, epigenetic literature, phenome-wide association studies are summarized for alcohol, nicotine, cannabinoids, cocaine, and opioids.

RESULTS

There are substantial genetic influences on SUD that are expected to influence multiple neurotransmission pathways, and these influences are particularly important within the dopaminergic system. Genetic influences involved in other aspects of SUD etiology including drug processing and metabolism are also identified. Studies of gene-environment interaction emphasize the importance of environmental context in SUD. Epigenetic studies indicate drug-specific changes in gene expression as well as differences in gene expression related to the use of multiple substances. Further, gene expression is expected to differ by stage of SUD such as substance initiation versus chronic substance use. While a substantial literature has developed for alcohol and nicotine use disorders, there is comparatively less information for other commonly abused substances.

CONCLUSIONS

A better understanding of genetically-mediated mechanisms involved in the neurobiology of SUD provides increased opportunity to develop behavioral and biologically based treatment and prevention of SUD.

Mismatch Amplification Mutation Assay Real-Time PCR Analysis of the Leptin Gene G2548A and A19G Polymorphisms and Serum Leptin in Infancy: A Preliminary Investigation

Leptin is a hormone that regulates food intake and energy metabolism. Its coding gene (LEP) is one of the most promising candidates for obesity. Although some studies have detected associations of different single nucleotide polymorphisms (SNPs) in the LEP gene with serum leptin levels and obesity-related traits, the results are still conflicting. We investigated two SNPs to find relationships with leptin concentrations. Thirty healthy Caucasian infants younger than 6 months were genotyped for the SNPs G2548A and A19G with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and amplification refractory mutation system-mismatch amplification mutation assay (ARMS- MAMA) real-time PCR, and serum leptin concentrations were measured with a radioimmunoassay method. Considering the significant linkage disequilibrium observed between the two SNPs, we divided the sample according to the number of GG haplotypes and observed that individuals homozygous for the GG haplotype had higher serum leptin levels in early infancy than the others. Although these preliminary results are based on a limited sample, they suggest that the genetic background seems to play a role in modulating leptin levels in infancy, but changes in leptin levels over infancy and their correlation with obesity need to be further explored. We describe an ARMS-MAMA real-time PCR procedure which could be profitably applied in routine genetic screening.

rs3751812, a common variant in fat mass and obesity-associated (FTO) gene, is associated with serum high- and low-density lipoprotein cholesterol in Pakistani individuals

OBJECTIVES

The aim of the present study was to investigate the effect of a common variant of the fat mass and obesity associated (FTO) gene, rs3751812 in obese Pakistani individuals, compare this effect with nonobese controls of the same ethnicity, and then correlate it with serum lipid profile and anthropometric parameters.

METHODS

We genotyped 475 samples using TaqMan allelic discrimination assay. Serum total cholesterol, triacylglycerols, and high- (HDL-C) and low-density lipoprotein cholesterol (LDL-C) concentrations were measured. Statistical analysis was done by SPSS version 22 and the results were analyzed for any significant associations.

RESULTS

Results demonstrated that the variant is significantly associated with obesity in Pakistan. The study found, for the first time, that the variant has a significant effect on lowering HDL-C and increasing LDL-C. Among anthropometric measures, the variant showed significant association with body mass index and weight.

CONCLUSION

The study concludes that the FTO variant is consistently associated with obesity in the Pakistani population and its association with anthropometric and lipid parameters show that it may mediate its role by altering fat deposition and disturbing serum lipid profile. However, future studies with larger sample size are needed to validate the results of the present study.

Nonlinear transcriptomic response to dietary fat intake in the small intestine of C57BL/6J mice

BACKGROUND

A high caloric diet, in conjunction with low levels of physical activity, promotes obesity. Many studies are available regarding the relation between dietary saturated fats and the etiology of obesity, but most focus on liver, muscle and white adipose tissue. Furthermore, the majority of transcriptomic studies seek to identify linear effects of an external stimulus on gene expression, although such an assumption does not necessarily hold. Our work assesses the dose-dependent effects of dietary fat intake on differential gene expression in the proximal, middle and distal sections of the small intestine in C57BL/6J mice. Gene expression is analyzed in terms of either linear or nonlinear responses to fat intake.

RESULTS

The highest number of differentially expressed genes was observed in the middle section. In all intestine sections, most of the identified processes exhibited a linear response to increasing fat intake. The relative importance of logarithmic and exponential responses was higher in the proximal and distal sections, respectively. Functional enrichment analysis highlighted a constantly linear regulation of acute-phase response along the whole small intestine, with up-regulation of Serpina1b. The study of gene expression showed that exponential down-regulation of cholesterol transport in the middle section is coupled with logarithmic up-regulation of cholesterol homeostasis. A shift from linear to exponential response was observed in genes involved in the negative regulation of caspase activity, from middle to distal section (e.g., Birc5, up-regulated).

CONCLUSIONS

The transcriptomic signature associated with inflammatory processes preserved a linear response in the whole small intestine (e.g., up-regulation of Serpina1b). Processes related to cholesterol homeostasis were particularly active in the middle small intestine and only the highest fat intake down-regulated cholesterol transport and efflux (with a key role played by the down-regulation of ATP binding cassette transporters). Characterization of nonlinear patterns of gene expression triggered by different levels of dietary fat is an absolute novelty in intestinal studies. This approach helps identifying which processes are overloaded (i.e., positive, logarithmic regulation) or arrested (i.e., negative, exponential regulation) in response to excessive fat intake, and can shed light on the relationships linking lipid intake to obesity and its associated molecular disturbances.

A novel treatment for weight reduction by the recombinant "Pichia pastoris" yeast expressing the hybrid protein of "irisin-furin-transferrin"

Obesity is a major health problem across the world, but there are few ways to effectively treat or manage it in the long term. Researchers are searching for more convenient, cost-effective and noninvasive therapies for overweight and obese people. Recent studies have illustrated that the microbiome of the body's different organs can be used as a vehicle for in-situ gene therapy. We suggest that the recombinant form of "Pichia pastoris" yeast expressing the hybrid protein of "irisin-furin-transferrin" under the control of the enolase 1 promoter is a new nutraceutical strategy to absorb fewer calories from intestinal nutrients, and induce a higher metabolic rate to expend more calories, similar to that from engaging in physical activity. By comparison, this method can be a long-term, noninvasive treatment and can be used for obese patients who have movement limitations.

Milk Leptin Surge and Biological Rhythms of Leptin and Other Regulatory Proteins in Breastmilk

A significant number of chronic diseases are linked to perinatal nutrition, and prevention may be associated to naturally occurring components of breast milk. One key hormone in breast milk is leptin, related with the protection from obesity in the adulthood, thus knowing its changes through the day or lactation is crucial. We aimed to investigate the daily rhythms in the milk levels of leptin, together with other two related hormones, ghrelin and adiponectin, during lactation (days 5, 10 and 15) in rat dams, and the relation with morphometric parameters (dams and pups). Summarizing the main results, the existence of biological rhythms, but not daily and maybe circasemidian, was confirmed for the three hormones at the earliest period of lactation. The correlations performed generally showed a possible dependence of milk hormone levels on plasma levels at the early phase of lactation, while with the progression of lactation this dependence may fade and the hormone levels are suggested to be more dependent on mammary gland production/maturation. There was also a correlation between milk leptin and adiponectin levels, especially in the first half of lactation, suggesting a possible parallel regulation. Interestingly, we describe a milk leptin surge around the mid of lactation (at day 10) which may be related with pup´s growth (males and females) and with the well-known (in the literature) plasma leptin surge in pups. All this knowledge may be crucial for future applications in the development of formula milk and in relation with the role of leptin surge during lactation.

Oral supplementations with L-glutamine or L-alanyl-L-glutamine do not change metabolic alterations induced by long-term high-fat diet in the B6.129F2/J mouse model of insulin resistance

In this work, we aimed to investigate the effects of long-term supplementations with L-glutamine or L-alanyl-L-glutamine in the high-fat diet (HFD)-fed B6.129SF2/J mouse model over insulin sensitivity response and signaling, oxidative stress markers, metabolism and HSP70 expression. Mice were fed in a standard low-fat diet (STA) or a HFD for 20 weeks. In the 21th week, mice from the HFD group were allocated in five groups and supplemented for additional 8 weeks with different amino acids: HFD control group (HFD-Con), HFD + dipeptide L-alanyl-L-glutamine group (HFD-Dip), HFD + L-alanine group (HFD-Ala), HFD + L-glutamine group (HFD-Gln), or the HFD + L-alanine + L-glutamine (in their free forms) group (HFD-Ala + Gln). HFD induced higher body weight, fat pad, fasted glucose, and total cholesterol in comparison with STA group. Amino acid supplementations did not induce any modifications in these parameters. Although insulin tolerance tests indicated insulin resistance in all HFD groups, amino acid supplementations did not improve insulin sensitivity in the present model. There were also no significant differences in the immunocontents of insulin receptor, Akt, and Toll-like receptor-4. Notably, total 70 kDa heat shock protein (HSP72 + HSP73) contents in the liver was markedly increased in HFD-Con group as compared to STA group, which might suggest that insulin resistance is only in the beginning. Apparently, B6.129SF2/J mice are more resistant to the harmful effects of HFD through a mechanism that may include gut adaptation, reducing the absorption of nutrients, including amino acids, which may explain the lack of improvements in our intervention.

Allelic variants of the Melanocortin 4 receptor (MC4R) gene in a South African study group

Obesity is a global epidemic that results in significant morbidity and mortality. Mutations in the melanocortin 4 receptor (MC4R) gene, which codes for a G-protein-coupled receptor responsible for postprandial satiety signaling, have been associated with monogenic obesity. The prevalence of obesity is on the increase in South Africa, and it is hypothesized that mutations in MC4R are a contributing factor. The aim of this study was to perform a retrospective assessment of the relationship between allelic variants of MC4R and BMI in a South African study cohort. DNA was isolated from a demographically representative cohort of 297 individuals and the entire MC4R gene sequenced by Sanger sequencing. Eight previously reported MC4R variants were identified in 42 of the 297 (14.1%) study participants. The most frequently observed MC4R alleles were V103I (4.0%), I170V (1.5%), and I198I (1.2%), while the remaining five variants together constituted 1.18%. Five compound heterozygotes were also detected. Although MC4R variants were rare, the majority of variation was observed in individuals of Black African ancestry. No statistically significant associations with BMI were reported. Given that lifestyle interventions have limited success in decreasing obesity, there is an urgent need to perform large-scale population studies to further elucidate the molecular underpinnings of this disease.

Effect of six type II diabetes susceptibility loci and an FTO variant on obesity in Pakistani subjects

The aim of the current study was to analyze the effect of six type II diabetes GWAS loci rs3923113 (GRB14), rs16861329 (ST6GAL1), rs1802295 (VPS26A), rs7178572 (HMG20A), rs2028299 (AP3S2) and rs4812829 (HNF4A), and an FTO polymorphism (rs9939609) on obesity. The probable mechanism of action of these SNPs was analyzed by studying their association with various biochemical and anthropometric parameters. A total of 475 subjects (obese=250, controls=225) were genotyped by TaqMan assay and their lipid profile was determined. Allele/genotype frequencies and an unweighted/weighted gene score were calculated. The effect of the gene score on anthropometric and biochemical parameters was analyzed. The minor allele frequencies of all variants were comparable to that reported in the original studies and were associated with obesity in these Pakistani subjects. Subjects with 9 risk alleles differ from those with <3 and overall there is no significant effect (P-value for trend 0.26). None of the SNPs were associated with any of the serum lipid traits. We are the first to report the association of these T2D SNPs with obesity. In the Pakistani population the reported effect of six SNPs for obesity is similar to that reported for T2D and having a combination of risk alleles on obesity can be considerable. The mechanism of this effect is unclear, but appears not to be mediated by changing serum lipid chemistry.

Effect of the Common Fat Mass and Obesity Associated Gene Variants on Obesity in Pakistani Population: A Case-Control Study

Background/Objective. Obesity has become a global epidemic due to an increase in the number of obese individuals worldwide. There is little research in the field of obesity genetics in Pakistan. The aim of the current study was to analyze the association of common variants in Fat Mass and Obesity associated (FTO) gene with obesity in Pakistan, to find out the effect of the selected SNPs on anthropometric and biochemical traits, and to observe whether these variants act synergistically. Methods. Samples from 631 subjects were taken after informed consent and were used for serum parameters and genetic analysis. Lipid profile was determined, tetra-ARMS PCR was used for genotyping, and allele/genotype frequencies and genescore were calculated. Results. All FTO variants were associated with obesity, and some biochemical and anthropometric measures and had higher minor allele frequencies than those reported for Asian populations previously. The risk allele of each single nucleotide polymorphism resulted in an increase in BMI in a quantitative manner. Conclusion. Common forms of obesity are due to a combined net effect of many variants presented in same or different genes. The more the number of risk alleles present, the higher the risk and severity of obesity resulting from an increase in BMI.

Linkage and association analysis of obesity traits reveals novel loci and interactions with dietary n-3 fatty acids in an Alaska Native (Yup'ik) population

OBJECTIVE

To identify novel genetic markers of obesity-related traits and to identify gene-diet interactions with n-3 polyunsaturated fatty acid (n-3 PUFA) intake in Yup'ik people.

MATERIAL AND METHODS

We measured body composition, plasma adipokines and ghrelin in 982 participants enrolled in the Center for Alaska Native Health Research (CANHR) Study. We conducted a genome-wide SNP linkage scan and targeted association analysis, fitting additional models to investigate putative gene-diet interactions. Finally, we performed bioinformatic analysis to uncover likely candidate genes within the identified linkage peaks.

RESULTS

We observed evidence of linkage for all obesity-related traits, replicating previous results and identifying novel regions of interest for adiponectin (10q26.13-2) and thigh circumference (8q21.11-13). Bioinformatic analysis revealed DOCK1, PTPRE (10q26.13-2) and FABP4 (8q21.11-13) as putative candidate genes in the newly identified regions. Targeted SNP analysis under the linkage peaks identified associations between three SNPs and obesity-related traits: rs1007750 on chromosome 8 and thigh circumference (P=0.0005), rs878953 on chromosome 5 and thigh skinfold (P=0.0004), and rs1596854 on chromosome 11 for waist circumference (P=0.0003). Finally, we showed that n-3 PUFA modified the association between obesity related traits and two additional variants (rs2048417 on chromosome 3 for adiponectin, P for interaction=0.0006 and rs730414 on chromosome 11 for percentage body fat, P for interaction=0.0004).

CONCLUSIONS

This study presents evidence of novel genomic regions and gene-diet interactions that may contribute to the pathophysiology of obesity-related traits among Yup'ik people.

Adipocyte secreted factors enhance aggressiveness of prostate carcinoma cells

Obesity has been associated with increased incidence and risk of mortality of prostate cancer. One of the proposed mechanisms underlying this risk association is the change in adipokines expression that could promote the development and progression of the prostate tumor cells. The main goal of this study was to evaluate the effect of preadipocyte and adipocyte secretome in the proliferation, migration and invasion of androgen independent prostate carcinoma cells (RM1) and to assess cell proliferation in the presence of the adiposity signals leptin and insulin. RM1 cells were co-cultured in with preadipocytes, adipocytes or cultured in their respective conditioned medium. Cell proliferation was assessed by flow cytometry and XTT viability test. Cell migration was evaluated using a wound healing injury assay of RM1 cells cultured with conditioned media. Cellular invasion of RM1 cells co-cultured with adipocytes and preadipocytes was assessed using matrigel membranes. Preadipocyte conditioned medium was associated with a small increase in RM1 proliferation, while adipocytes conditioned media significantly increased RM1 cell proliferation (p<0.01). Adipocytes also significantly increased the RM1 cells proliferation in co-culture (p <0.01). Cell migration was higher in RM1 cells cultured with preadipocyte and adipocyte conditioned medium. RM1 cell invasion was significantly increased after co-culture with preadipocytes and adipocytes (p <0.05). Insulin also increased significantly the cell proliferation in contrast to leptin, which showed no effect. In conclusion, prostate carcinoma cells seem to be influenced by factors secreted by adipocytes that are able to increase their ability to proliferate, migrate and invade.

Clinically relevant known and candidate genes for obesity and their overlap with human infertility and reproduction

PURPOSE

Obesity is a growing public health concern now reaching epidemic status worldwide for children and adults due to multiple problems impacting on energy intake and expenditure with influences on human reproduction and infertility. A positive family history and genetic factors are known to play a role in obesity by influencing eating behavior, weight and level of physical activity and also contributing to human reproduction and infertility. Recent advances in genetic technology have led to discoveries of new susceptibility genes for obesity and causation of infertility. The goal of our study was to provide an update of clinically relevant candidate and known genes for obesity and infertility using high resolution chromosome ideograms with gene symbols and tabular form.

METHODS

We used computer-based internet websites including PubMed to search for combinations of key words such as obesity, body mass index, infertility, reproduction, azoospermia, endometriosis, diminished ovarian reserve, estrogen along with genetics, gene mutations or variants to identify evidence for development of a master list of recognized obesity genes in humans and those involved with infertility and reproduction. Gene symbols for known and candidate genes for obesity were plotted on high resolution chromosome ideograms at the 850 band level. Both infertility and obesity genes were listed separately in alphabetical order in tabular form and those highlighted when involved with both conditions.

RESULTS

By searching the medical literature and computer generated websites for key words, we found documented evidence for 370 genes playing a role in obesity and 153 genes for human reproduction or infertility. The obesity genes primarily affected common pathways in lipid metabolism, deposition or transport, eating behavior and food selection, physical activity or energy expenditure. Twenty-one of the obesity genes were also associated with human infertility and reproduction. Gene symbols were plotted on high resolution ideograms and their name, precise chromosome band location and description were summarized in tabular form.

CONCLUSIONS

Meaningful correlations in the obesity phenotype and associated human infertility and reproduction are represented with the location of genes on chromosome ideograms along with description of the gene and position in tabular form. These high resolution chromosome ideograms and tables will be useful in genetic awareness and counseling, diagnosis and treatment to improve clinical outcomes.

Pesticides in mixture disrupt metabolic regulation: in silico and in vivo analysis of cumulative toxicity of mancozeb and imidacloprid on body weight of mice

Pesticides acting as endocrine disrupting chemicals disrupt the homeostasis of body metabolism. The present study elucidated that the low dose coexposure of thyroid disrupting dithiocarbamate fungicide mancozeb (MCZ) and neonicotinoid insecticide imidacloprid (IMI) during lactation increased the risk of body weight gain in mice later in life. Body weight gain has been linked to pesticide-induced hypothyroidism and hyperprolactinemia and alteration of lipid profiles. In vivo results were substantiated with in silico molecular docking (MD) analysis that predicted the binding affinity of pesticides with thyroid hormone receptors (TRα and TRβ) and peroxisome proliferator activated receptor gamma (PPARγ), the major nuclear receptors of peripheral fat metabolism. Binding potency of MCZ and IMI was compared with that of T3, and its antagonist ethylene thiourea (ETU) as well as PPARγ agonist (rosiglitazone) and antagonist (HL005). MD simulation predicted that both MCZ and IMI may compete with T3 for binding with TRs. Imidazole group of IMI formed hydrogen bonds with TRs like that of ETU. MCZ may compete with rosiglitazone and HL005 for PPARγ, but IMI showed no affinity. Thus while both MCZ and IMI could disrupt the TRs functioning, MCZ alone may affect PPARγ. Coexposure of pesticides decreased the plasma thyroid hormones and increased the cholesterol and triglyceride. Individual pesticide exposure in low dose might not exert the threshold response to affect the receptors signaling further to cause hormonal/metabolic impairment. Thus, cumulative response of the mixture of thyroid disrupting pesticides can disrupt metabolic regulation through several pathways and contribute to gain in body weight.

Education and WHO recommendations for fruit and vegetable intake are associated with better cognitive function in a disadvantaged Brazilian elderly population: a population-based cross-sectional study

Brazil has one of the fastest aging populations in the world and the incidence of cognitive impairment in the elderly is expected to increase exponentially. We examined the association between cognitive impairment and fruit and vegetable intake and associated factors in a low-income elderly population. A cross-sectional population-based study was carried out with 1849 individuals aged 65 or over living in São Paulo, Brazil. Cognitive function was assessed using the Community Screening Instrument for Dementia (CSI-D). Fruit and vegetable intake was assessed with a Food Frequency Questionnaire (FFQ) and categorized into quartiles of intake and into total daily fruit and vegetable intake using the cut-off points for the WHO recommendations (<400grams/day or ≥400 grams/day). The association between cognitive impairment and each quartile of intake, and WHO recommendation levels, was evaluated in two separate multivariate logistic models. The WHO recommendations for daily intakes ≥400 grams/day were significantly associated with 47% decreased prevalence of cognitive impairment. An effect modification was found in both models between cognitive impairment and “years of education and physical activity” and “years of education and blood levels of HDL” So that, having 1 or more years of education and being physically active or having 1 or more years of education and levels higher than 50 mg/dl of HDL-cholesterol strongly decreased the prevalence of cognitive impairment. In this socially deprived population with very low levels of education and physical activity and fruit and vegetable intake, those who attained WHO recommendations, had 1 year or more of education and were physically active had a significantly lower prevalence of cognitive impairment. A more comprehensive understanding of the social determinants of mental health is needed to develop effective public policies in developing countries.

CART in the brain of vertebrates: circuits, functions and evolution

Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.

Investigation of melanocortin system gene variants in antipsychotic-induced weight gain

OBJECTIVES

The use of second-generation antipsychotic medications may result in substantial weight gain in a subset of schizophrenia patients. Distinct populations of neurons expressed in the hypothalamus, including the cocaine- and amphetamine-regulated transcript (CART), the polypeptide pro-opiomelanocortin (POMC) and the agouti-related protein (AGRP), have regulatory roles in weight control and energy homeostasis. Thus, we investigated the potential role of CART, POMC and AGRP genetic variants in antipsychotic-induced weight gain (AIWG).

METHODS

Five CART single nucleotide polymorphisms (SNPs) (rs10515115, rs3763153, rs3857384, rs11575893, rs16871471), three POMC SNPs (rs6713532, rs1047521, rs3754860) and one AGRP SNP (rs1338993), were genotyped in 218 patients treated with antipsychotics for chronic schizophrenia and evaluated for AIWG. We compared weight change (%) across genotypic groups using analysis of covariance.

RESULTS

None of the SNPs in POMC, CART, AGRP were significantly associated with AIWG in the refined samples stratified by ethnicity and medication treatment.

CONCLUSIONS

In this exploratory study, we observed that POMC, CART and AGRP gene variants are not a major contributor to AIWG. However larger samples are required to completely rule out their effect on AIWG.

Identification of pleiotropic genetic effects on obesity and brain anatomy

BACKGROUND/AIMS

Obesity is a major contributor to the global burden of chronic disease and disability, though current knowledge of causal biologic underpinnings is lacking. Through the regulation of energy homeostasis and interactions with adiposity and gut signals, the brain is thought to play a significant role in the development of this disorder. While neuroanatomical variation has been associated with obesity, it is unclear if this relationship is influenced by common genetic mechanisms. In this study, we sought genetic components that influence both brain anatomy and body mass index (BMI) to provide further insight into the role of the brain in energy homeostasis and obesity.

METHODS

MRI images of brain anatomy were acquired in 839 Mexican American individuals from large extended pedigrees. Bivariate linkage and quantitative analyses were performed in SOLAR.

RESULTS

Genetic factors associated with an increased BMI were also associated with a reduced cortical surface area and subcortical volume. We identified two genome-wide quantitative trait loci that influenced BMI and the ventral diencephalon volume, and BMI and the supramarginal gyrus surface area, respectively.

CONCLUSIONS

This study represents the first genetic analysis seeking evidence of pleiotropic effects acting on both brain anatomy and BMI. Our results suggest that a region on chromosome 17 contributes to the development of obesity, potentially through leptin-induced signaling in the hypothalamus, and that a region on chromosome 3 appears to jointly influence the food-related reward circuitry and the supramarginal gyrus.

Clinical phenotype of bipolar disorder with comorbid binge eating disorder

BACKGROUND

To explore the relationship between binge eating disorder (BED) and obesity in patients with bipolar disorder (BP).

METHODS

717 patients participating in the Mayo Clinic Bipolar Biobank completed structured diagnostic interviews and questionnaires for demographic and illness-related variables. They also had weight and height measured to determine body mass index (BMI). The effects of BED and obesity (BMI≥30 kg/m(2)), as well as their interaction, were assessed on one measure of general medical burden and six proxies of psychiatric illness burden.

RESULTS

9.5% of patients received a clinical diagnosis of BED and 42.8% were obese. BED was associated with a significantly elevated BMI. Both BED and obesity were associated with greater psychiatric and general illness burden, but illness burden profiles differed. After controlling for obesity, BED was associated with suicidality, psychosis, mood instability, anxiety disorder comorbidity, and substance abuse comorbidity. After controlling for BED status, obesity was associated with greater general medical comorbidity, but lower substance abuse comorbidity. There were no significant interaction effects between obesity and BED, or BMI and BED, on any illness burden outcome.

LIMITATIONS

There may have been insufficient power to detect interactions between BED and obesity.

CONCLUSIONS

Among patients with BP, BED and obesity are highly prevalent and correlated, but associated with different profiles of enhanced illness burden. As the association of BED with greater psychiatric illness burden remained significant even after accounting for the effect of obesity, BP with BED may represent a clinically important sub-phenotype.

A meta-analysis of reference values of leptin concentration in healthy postmenopausal women

Objective

There are numerous reports about the leptin concentration (LC) in postmenopausal women (PW). Changes in LC can elicit different clinical outcomes. We systematically analyzed the LC in PW.

Methods

A search was conducted in original English-language studies published from 1994 to October 2012 in the following databases: Medline (78), Cochrane Center (123) Embase (505), Biological abstracts (108), Cochrane (53) and Science Finder Scholar (0). A meta-analysis was undertaken on the correction coefficient (r) between the serum LC and body mass index (BMI) for healthy PW across studies containing a dataset and sample size. Pre-analytical and analytical variations were examined. Pre-analytical variables included fasting status (FS) and sampling timing. Analytical variation comprised assay methodology, LC in those undertaking hormone replacement therapy (HRT) and those not having HRT as well as LC change according to age.

Results

Twenty-seven studies met the inclusion criteria. Eighteen studies detected LC in the morning in a FS, 15 studies denoted the r between leptin and the BMI. A combined r was counted for the 15 studies (r = 0.51 [95% confidence interval (CI), 0.46–0.54], P = 0.025), and if sampling collection was in the FSat morning, a combined r was form 10 studies (r = 0.54 [95% CI, 0.45–0.54], P = 0.299) and heterogeneity was diminished. LC did not change between HRT users and non-users in 7 studies. Five studies analyzed changes in LC according to age.

Conclusion

Based on all studies that investigated both LC and BMI, LC was positively correlated with the BMI. No studies established reference ranges according to the Clinical and Laboratory Standards Institute (CLSI) in healthy PW, and there was a wide variation in LC values. These differences suggest that caution should be used in the interpretation and comparison between studies.

Morbid obesity-the new pandemic: medical and surgical management, and implications for the practicing gastroenterologist

The gastroenterologist, whether in academic or clinical practice, must face the reality that an increasingly large percentage of adult patients are morbidly obese. Morbid obesity is associated with significant morbidity and mortality including enhanced morbidity from cardiovascular, cerebrovascular, hepatobiliary and colonic diseases. Most of these associated diseases are actually preventable. Based on the 1991 NIH consensus conference criteria, for most patients with a body mass index (BMI=weight in kilograms divided by the height in meters squared) of 40 or more, or for patients with a BMI of 35 or more and significant health complications, surgery may be the only reliable option. Currently in the United States, over 250,000 bariatric surgical procedures are being performed annually. The practicing gastroenterologist in every community, large and small, must be familiar with the various surgical procedures together with their associated anatomic changes. These changes may dramatically increase the prevalence of nutritional deficiencies and profoundly alter the clinical and endoscopic approaches to diagnosis and management.

Conceptual heuristic models of the interrelationships between obesity and the occupational environment

OBJECTIVE

Research and interventions targeting the relationship between work, its attendant occupational hazards, and obesity are evolving but merit further consideration in the public health arena. In this discussion paper, conceptual heuristic models are described examining the role of obesity as both a risk factor and health outcome in the occupational setting.

METHODS

PubMed was searched using specific criteria from 2000 and onwards for evidence to support conceptual models in which obesity serves as a risk factor for occupational disease or an outcome of occupational exposures. Nine models are presented: four where obesity is a risk factor and five where it is an adverse effect.

RESULTS

A broad range of work-related health effects are associated with obesity including musculoskeletal disorders, asthma, liver disease, and cardiovascular disease, among others. Obesity can be associated with occupational hazards such as shift work, sedentary work, job stress, and exposure to some chemicals.

CONCLUSION

Identification of combinations of risk factors pertinent to obesity in the occupational environment will provide important guidance for research and prevention.

Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence

The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (p_c = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (p_c = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

Copy number variants in obesity-related syndromes: review and perspectives on novel molecular approaches

In recent decades, obesity has reached epidemic proportions worldwide and became a major concern in public health. Despite heritability estimates of 40 to 70% and the long-recognized genetic basis of obesity in a number of rare cases, the list of common obesity susceptibility variants by the currently published genome-wide association studies (GWASs) only explain a small proportion of the individual variation in risk of obesity. It was not until very recently that GWASs of copy number variants (CNVs) in individuals with extreme phenotypes reported a number of large and rare CNVs conferring high risk to obesity, and specifically deletions on chromosome 16p11.2. In this paper, we comment on the recent advances in the field of genetics of obesity with an emphasis on the genes and genomic regions implicated in highly penetrant forms of obesity associated with developmental disorders. Array genomic hybridization in this patient population has afforded discovery opportunities for CNVs that have not previously been detectable. This information can be used to generate new diagnostic arrays and sequencing platforms, which will likely enhance detection of known genetic conditions with the potential to elucidate new disease genes and ultimately help in developing a next-generation sequencing protocol relevant to clinical practice.