Genetics of Obesity: What have we Learned?

Molecular pathway analysis associates alterations in obesity-related genes and antipsychotic-induced weight gain

OBJECTIVE

Antipsychotics often induce excessive weight gain. We hypothesised that individuals with genetic variations related to known obesity-risk genes have an increased risk of excessive antipsychotic-induced weight gain (AIWG). This hypothesis was tested in a subset of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial data set.

METHODS

The CATIE trial compared effects and side effects of five different antipsychotics through an 18-month period. Based on the maximum weight gain recorded, excessive weight gain was defined as >7% weight gain. Cytoscape and GeneMANIA were instrumental in composing a molecular pathway from eight selected genes linked to obesity. Genetic information on a total of 495.172 single-nucleotide polymorphisms (SNPs) were available from 765 (556 males) individuals. Enrichment test was conducted through ReactomePA and Bioconductor. A permutation test was performed, testing the generated pathway against 105 permutated pathways (p ≤ 0.05). In addition, a standard genome-wide association study (GWAS) analysis was performed.

RESULT

GWAS analysis did not detect significant differences related to excessive weight gain. The pathway generated contained 28 genes. A total of 2067 SNPs were significantly expressed (p < 0.01) within this pathway when comparing excessive weight gainers to the rest of the sample. Affected genes including PPARG and PCSK1 were not previously related to treatment-induced weight gain.

CONCLUSIONS

The molecular pathway composed from high-risk obesity genes was shown to overlap with genetics of patients who gained >7% weight gain during the CATIE trial. This suggests that genes related to obesity compose a pathway of increased risk of excessive AIWG. Further independent analyses are warranted that may confirm or clarify the possible reasoning behind.

Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus

Insulin, a hormone produced by pancreatic β-cells, has a primary function of maintaining glucose homeostasis. Deficiencies in β-cell insulin secretion result in the development of type 1 and type 2 diabetes, metabolic disorders characterized by high levels of blood glucose. Type 2 diabetes mellitus (T2DM) is characterized by the presence of peripheral insulin resistance in tissues such as skeletal muscle, adipose tissue and liver and develops when β-cells fail to compensate for the peripheral insulin resistance. Insulin resistance triggers a rise in insulin demand and leads to β-cell compensation by increasing both β-cell mass and insulin secretion and leads to the development of hyperinsulinemia. In a vicious cycle, hyperinsulinemia exacerbates the metabolic dysregulations that lead to β-cell failure and the development of T2DM. Insulin and IGF-1 signaling pathways play critical roles in maintaining the differentiated phenotype of β-cells. The autocrine actions of secreted insulin on β-cells is still controversial; work by us and others has shown positive and negative actions by insulin on β-cells. We discuss findings that support the concept of an autocrine action of secreted insulin on β-cells. The hypothesis of whether, during the development of T2DM, secreted insulin initially acts as a friend and contributes to β-cell compensation and then, at a later stage, becomes a foe and contributes to β-cell decompensation will be discussed.

Dietary patterns interact with chromosome 9p21 rs1333048 polymorphism on the risk of obesity and cardiovascular risk factors in apparently healthy Tehrani adults

PURPOSE

Gene-dietary patterns may contribute to determining body composition and related biochemical indices. The aim of this study was to evaluate interactions between rs1333048 polymorphism and major dietary patterns on body fat percentage, general and central obesity, and related biochemical measurements.

METHODS

This cross-sectional study was conducted on 265 healthy Tehrani adults with mean age of 35 years (47.5% men, 52.5% women). Dietary patterns (DPs) were extracted by factor analysis. Bioelectrical impedance analysis was used for body analysis and rs1333048 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Three DPs were extracted: restricted refined grains DP, legumes DP and healthy DP. AA genotype compared to CC genotype had greater odds for general obesity before (OR 3.14; 95% CI 1.008-9.60, P = 0.045) and after (OR 3.11; 95% CI 1.008-9.60, P = 0.048) adjusting for potential confounders. Individuals with AA genotype were more likely to be centrally obese before (OR 2.09; 95% CI 1.006-4.35, P = 0.048) and after (OR 2.63; 95% CI 1.12-6.17, P = 0.026) controlling for potential confounders. Significant interactions were observed between Legumes DP and rs1333048 SNP on waist circumference (P = 0.047), body fat % (BFP) (P = 0.048), hs-Crp (P = 0.042), BMI (P = 0.073), WHtR (P = 0.063) and odds for general obesity (P = 0.051). Following this DP reduced all these items for individuals with CC genotype, whereas increased them for people who carry CA or AA genotypes.

CONCLUSIONS

The findings indicate that there are significant associations between AA genotype of rs1333048 SNP and general and central obesity, and significant interaction between alleles of this SNP and major dietary patterns on the odds of general obesity, BFP, waist circumference, BMI, WHtR and hs-Crp.

Precision Surgery for Obesity

Precision medicine is targeted towards improving the effectiveness of treatment, reducing the side effects of drugs and reducing medical costs. The application of precision surgery for obesity is a new concept that involves 2 stages: the first stage is to attain a precise obesity surgery, and the second stage is to achieve individualized obese gene therapy. In this article, we discuss the value of precision surgery for obesity, its stages and its future application to improve obesity surgery. Due to recent advancements in medical technologies, genetics, surgical and clinical research; precision surgery for obesity will lead the future of obesity surgery.

Epidemiology, Predisposing Factors, Biomarkers, and Prevention Mechanism of Obesity: A Systematic Review

Background. Globally, obesity is becoming a public health problem in the general population. Various determinants were reported by different scholars even though there are inconsistencies. Different biomarkers of obesity were identified for the prediction of obesity. Even though researchers speculate the factors, biomarkers, consequences, and prevention mechanisms, there is a lack of aggregate and purified data in the area of obesity. Summary. In this review, the epidemiology, predisposing factors, biomarkers, consequences, and prevention approaches of obesity were reviewed. Key Messages. The epidemiology of obesity increased in low-, middle-, and high-income countries. Even if the factors vary across regions and socioeconomic levels, sociodemographic, behavioral, and genetic factors were prominent for the development of obesity. There are a lot of biomarkers for obesity, of which microRNA, adipocytes, oxidative stress, blood cell profile, nutrients, and microbiota were promising biomarkers for determination of occurrence of obesity. Since the consequences of obesity are vast and interrelated, multidimensional prevention strategy is mandatory in all nations.

Benefits and limitations of genome-wide association studies

Genome-wide association studies (GWAS) involve testing genetic variants across the genomes of many individuals to identify genotype-phenotype associations. GWAS have revolutionized the field of complex disease genetics over the past decade, providing numerous compelling associations for human complex traits and diseases. Despite clear successes in identifying novel disease susceptibility genes and biological pathways and in translating these findings into clinical care, GWAS have not been without controversy. Prominent criticisms include concerns that GWAS will eventually implicate the entire genome in disease predisposition and that most association signals reflect variants and genes with no direct biological relevance to disease. In this Review, we comprehensively assess the benefits and limitations of GWAS in human populations and discuss the relevance of performing more GWAS.

Effect of inactivated Bifidobacterium longum intake on obese diabetes model mice (TSOD)

Obesity and diabetes have been increasing at an alarming rate worldwide. Studies have shown the futility of chemical drugs in the treatment of obesity and diabetes. Bifidobacterium longum (BL), a common member of the gut microbiota throughout the human lifespan, has been widely reported to play a role in host health and disease. Here, we evaluated the effects of inactivated cells of BL (IBL) on obesity and blood glucose levels in TSOD mice by administering IBL orally for 5 weeks. The treated mice showed a significant decrease of body weight gain, adipose tissue mass and blood glucose levels, as well as a significant reduction in blood glucose during an oral glucose tolerance test. The treatment also resulted in reduced levels of cholesterol, triglycerides, and NEFA. Moreover, serum and urine analysis showed low creatinine levels in IBL-treated mice. These data demonstrate that IBL may have the potential to prevent obesity and diabetes.

Obesity in Childhood and Adolescence, Genetic Factors

Obesity and excess weight are a pandemic phenomenon in the modern world. Childhood and adolescent obesity often ends up in obesity in adults. The costs of obesity and its consequences are staggering for any society, crippling for countries in development. Childhood obesity is also widespread in Macedonia. Metabolic syndrome, dyslipidemia and carbohydrate intolerance are found in significant numbers. Parents and grandparents are often obese. Some of the children are either dysmorphic, or slightly retarded. We have already described patients with Prader-Willi syndrome, Bardet-Biedl syndrome or WAGR syndrome. A genetic screening for mutations in monogenic obesity in children with early, rapid-onset or severe obesity, severe hyperphagia, hypogonadism, intestinal dysfunction, hypopigmentation of hair and skin, postprandial hypoglycaemia, diabetes insipidus, abnormal leptin level and coexistence of lean and obese siblings in the family discovers many genetic forms of obesity. There are about 30 monogenic forms of obesity. In addition, obesity is different in ethnic groups, and the types of monogenic obesity differ. In brief, an increasing number of genes and genetic mechanisms in children continue to be discovered. This sheds new light on the molecular mechanisms of obesity and potentially gives a target for new forms of treatment.

Rats Selectively Bred for High Voluntary Physical Activity Behavior are Not Protected from the Deleterious Metabolic Effects of a Western Diet When Sedentary

BACKGROUND

Physical activity and diet are well-established modifiable factors that influence chronic disease risk. We developed a selectively bred, polygenic model for high and low voluntary running (HVR and LVR, respectively) distances. After 8 generations, large differences in running distance were noted. Despite these inherent behavioral differences in physical activity levels, it is unknown whether HVR rats would be inherently protected from diet-induced metabolic dysfunction.

OBJECTIVES

The aim of this study was to determine whether HVR rats without voluntary running wheels would be inherently protected from diet-induced metabolic dysfunction.

METHODS

Young HVR, LVR, and a wild-type (WT) control group were housed with no running wheel access and fed either a normal diet (ND) or a high-sugar/fat Western diet (WD) for 8 wk. Body weight, percentage body fat (by dual-energy X-ray absorptiometry scan), blood lipids [total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides (TGs), nonesterified fatty acids], and hepatic TG content were measured, and indices of insulin sensitivity were determined via an intravenous glucose tolerance test. Additionally, weekly energy intake and feed efficiency were calculated.

RESULTS

After 8 wk, significant differences in body weight and body fat percentage were noted in all WD animals compared with ND animals, with the LVR-WD exhibiting the greatest increase due, in part, to their enhanced feed efficiency. Lipid dysregulation was present in all WD rat lines compared with ND counterparts. Furthermore, LVR-WD rats had higher total cholesterol, HDL cholesterol, and TG concentrations, and higher areas under the curve (AUC) for insulin than HVR-WD and WT-WD, although HVR-WD animals had higher AUCglucose than both LVR-WD and WT-WD and higher LDL than WT-WD.

CONCLUSIONS

In the absence of high voluntary running behavior, the genetic predisposition for high running in HVR did not largely protect them from the deleterious effects of a WD compared with LVR, suggesting genetic factors influencing physical activity levels may, in part, be independent from genes influencing metabolism.

Cyp2b-null male mice are susceptible to diet-induced obesity and perturbations in lipid homeostasis

Obesity is an endemic problem in the United States and elsewhere, and data indicate that in addition to overconsumption, exposure to specific chemicals enhances obesity. CYP2B metabolizes multiple endo- and xenobiotics, and recent data suggests that repression of Cyp2b activity increases dyslipidemia and age-onset obesity, especially in males. To investigate the role played by Cyp2b in lipid homeostasis and obesity, we treated wildtype and Cyp2b-null mice with a normal (ND) or 60% high-fat diet (HFD) for 10 weeks and determined metabolic and molecular changes. Male HFD-fed Cyp2b-null mice weigh 15% more than HFD-fed wildtype mice, primarily due to an increase in white adipose tissue (WAT); however, Cyp2b-null female mice did not demonstrate greater body mass or WAT. Serum parameters indicate increased ketosis, leptin and cholesterol in HFD-fed Cyp2b-null male mice compared to HFD-fed wildtype mice. Liver triglycerides and liver:serum triglyceride ratios were higher than their similarly treated wildtype counterparts in Cyp2b-null male mice, indicating a role for Cyp2b in fatty acid metabolism regardless of diet. Furthermore, RNAseq demonstrates that hepatic gene expression in ND-fed Cyp2b-null male mice is similar to HFD-fed WT male mice, suggestive of fatty liver disease progression and a role for Cyp2b in lipid homeostasis. Females did not show as demonstrative changes in liver health, and significantly fewer changes in gene expression, as well as gene expression associated with liver disease. Overall our data indicates that the repression or inhibition of CYP2B may exacerbate metabolic disorders and cause obesity by perturbing fatty acid metabolism, especially in males.

Prognostic biomarkers in renal cell carcinoma: is there a relationship with obesity?

Obesity is a recognized risk factor for renal cell carcinoma (RCC) the commonest form of kidney cancer. Both obesity and RCC are serious diseases with increasing incidence yearly. This review examined certain obesity associated measurements and adipokines as detection/prognostic indicators for RCC. The obesity related measurements such as body mass index (BMI), waist circumstance (WC), waist-hip ratio (WHR) in predicting RCC are valid when used in conjunction with other risk factors such as age and sex or with histological findings. The adipokine adiponectin holds promising outcomes as a predictive marker in assessing the risk of developing RCC. In addition, tissue leptin/leptin receptor may be a distinguishing marker for RCC subtypes. However, circulating leptin may not be a suitable detection or prognostic biomarker for RCC. The other less investigated adipokines; omentin, visfatin, apelin and resistin are also expressed in RCC but their prognostic capabilities are still inconclusive. BMI, WC and adipokines may be useful additions in a nomogram which includes TNM staging and pathological grading system to detect, confirm and follow-up RCC cases.

Road traffic noise and markers of adiposity in the Danish Nurse Cohort: A cross-sectional study

BACKGROUND

Studies have suggested that traffic noise is associated with markers of obesity. We investigated the association of exposure to road traffic noise with body mass index (BMI) and waist circumference in the Danish Nurse Cohort.

METHODS

We used data on 15,501 female nurses (aged >44 years) from the nationwide Danish Nurse Cohort who, in 1999, reported information on self-measured height, weight, and waist circumference, together with information on socioeconomic status, lifestyle, work and health. Road traffic noise at the most exposed façade of the residence was estimated using Nord2000 as the annual mean of a weighted 24-h average (L_den). We used multiple linear regression models to examine associations of road traffic noise levels in 1999 (1-year mean) with BMI and waist circumference, adjusting for potential confounders, and evaluated effect modification by degree of urbanization, air pollution levels, night shift work, job strain, sedative use, sleep aid use, and family history of obesity.

RESULTS

We did not observe associations between road traffic noise (per 10 dB increase in the 1-year mean L_den) and BMI (kg/m²) (β: 0.00; 95% confidence interval (CI): -0.07, 0.07) or waist circumference (cm) (β: -0.09; 95% CI: -0.31, 0.31) in the fully adjusted model. We found significant effect modification of job strain and degree of urbanization on the associations between L_den and both BMI and waist circumference. Job strained nurses were associated with a 0.41 BMI-point increase, (95% CI: 0.06, 0.76) and a 1.00 cm increase in waist circumference (95% CI: 0.00, 2.00). Nurses living in urban areas had a statistically significant positive association of L_den with BMI (β: 0.26; 95% CI: 0.11, 0.42), whilst no association was found for nurses living in suburban and rural areas.

CONCLUSION

Our results suggest that road traffic noise exposure in nurses with particular susceptibilities, such as those with job strain, or living in urban areas, may lead to increased BMI, a marker of adiposity.

Efficacy of dietary intervention and physical activity in children and adolescents with nonalcoholic fatty liver disease associated with obesity: A scoping review

AIM

To identify and discuss the efficacy of dietary interventions, antioxidant supplementation, physical activity, and nutritional and psychologic counseling in the treatment of children and adolescents with non alcoholic fatty liver disease associated with obesity.

MATERIALS AND METHODS

A scoping review of studies on nutritional and educational interventions and physical activity in pediatric patients with non alcoholic fatty liver disease was conducted. A search for randomized clinical trials or quasi-experimental studies published up to December 2017 was carried out, utilizing seven databases (Medline, EBSCO, OVID, Science Direct, JSTOR, Wiley, and Biblioteca Digital UDG).

RESULTS

From a total of 751 articles, 729 were excluded due to the criteria of age, design, language, diagnostic method, and outcome variables. The analysis included 22 articles. The most frequently used intervention variables were diet and physical activity. The interventions had different durations, but most were carried out for one year. Some authors employed ascorbic acid, vitamin E, or omega-3 fatty acid supplementation. There were varying degrees of improvement in the variables analyzed in the majority of the studies, such as a decrease in ALT levels, a reduced frequency of steatosis determined through imaging studies, and a decrease in body mass index.

CONCLUSIONS

The dietary interventions, omega-3 fatty acid supplementation, physical activity, and nutritional and psychologic counseling were identified as efficacious measures in the treatment of non alcoholic fatty liver disease associated with obesity in children and adolescents, according to biochemical or imaging study indicators, within the time frame of the intervention.

Association between DNA methylation in obesity-related genes and body mass index percentile in adolescents

Childhood obesity remains an epidemic in the U.S. and worldwide. However, little is understood regarding the epigenetic basis of obesity in adolescents. To investigate the cross-sectional association between DNA methylation level in obesity-related genes and body mass index (BMI) percentile, data from 263 adolescents in the population-based Penn State Child Cohort follow-up exam was analysed. Using DNA extracted from peripheral leukocytes, epigenome-wide single nucleotide resolution of DNA methylation in cytosine-phosphate-guanine (CpG) sites and surrounding regions was obtained. We used multivariable-adjusted linear regression models to assess the association between site-specific methylation level and age- and sex-specific BMI percentile. Hypergeometric and permutation tests were used to determine if obesity-related genes were significantly enriched among all intragenic sites that achieved a p < 0.05 throughout the epigenome. Among the 5,669 sites related to BMI percentile with p < 0.05, 28 were identified within obesity-related genes. Obesity-related genes were significantly enriched among 103,466 intragenic sites (P_{hypergeometric} = 0.006; P_permutation = 0.006). Moreover, increased methylation on one site within SIM1 was significantly related to higher BMI percentile (P = 4.2E-05). If externally validated, our data would suggest that DNA methylation in obesity-related genes may relate to obesity risk in adolescents.

Prader-Willi Syndrome - Clinical Genetics, Diagnosis and Treatment Approaches: An Update

BACKGROUND

Prader-Willi Syndrome (PWS) is a neurodevelopmental genomic imprinting disorder with lack of expression of genes inherited from the paternal chromosome 15q11-q13 region usually from paternal 15q11-q13 deletions (about 60%) or maternal uniparental disomy 15 or both 15s from the mother (about 35%). An imprinting center controls the expression of imprinted genes in the chromosome 15q11-q13 region. Key findings include infantile hypotonia, a poor suck, failure to thrive and hypogonadism/hypogenitalism. Short stature and small hands/feet due to growth and other hormone deficiencies, hyperphagia and marked obesity occur in early childhood, if uncontrolled. Cognitive and behavioral problems (tantrums, compulsions, compulsive skin picking) are common.

OBJECTIVE

Hyperphagia and obesity with related complications are major causes of morbidity and mortality in PWS. This report will describe an accurate diagnosis with determination of specific genetic subtypes, appropriate medical management and best practice treatment approaches.

METHODS AND RESULTS

An extensive literature review was undertaken related to genetics, clinical findings and laboratory testing, clinical and behavioral assessments and summary of updated health-related information addressing the importance of early PWS diagnosis and treatment. A searchable, bulleted and formatted list of topics is provided utilizing a Table of Contents approach for the clinical practitioner.

CONCLUSION

Physicians and other health care providers can use this review with clinical, genetic and treatment summaries divided into sections pertinent in the context of clinical practice. Frequently asked questions by clinicians, families and other interested participants or providers will be addressed.

How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases

Westernized populations are plagued by a plethora of chronic non-infectious degenerative diseases, termed as "civilization diseases", like obesity, diabetes, cardiovascular diseases, cancer, autoimmune diseases, Alzheimer's disease and many more, diseases which are rare or virtually absent in hunter-gatherers and other non-westernized populations. There is a growing awareness that the cause of this amazing discrepancy lies in the profound changes in diet and lifestyle during recent human history. This paper shows that the transition from Paleolithic nutrition to Western diets, along with lack of corresponding genetic adaptations, cause significant distortions of the fine-tuned metabolism that has evolved over millions of years of human evolution in adaptation to Paleolithic diets. With the increasing spread of Western diet and lifestyle worldwide, overweight and civilization diseases are also rapidly increasing in developing countries. It is suggested that the diet-related key changes in the developmental process include an increased production of reactive oxygen species and oxidative stress, development of hyperinsulinemia and insulin resistance, low-grade inflammation and an abnormal activation of the sympathetic nervous system and the renin-angiotensin system, all of which play pivotal roles in the development of diseases of civilization. In addition, diet-related epigenetic changes and fetal programming play an important role. The suggested pathomechanism is also able to explain the well-known but not completely understood close relationship between obesity and the wide range of comorbidities, like type 2 diabetes mellitus, cardiovascular disease, etc., as diseases of the same etiopathology. Changing our lifestyle in accordance with our genetic makeup, including diet and physical activity, may help prevent or limit the development of these diseases.

A Study of Short- and Long-term mRNA Levels of the Retn, Iapp, and Drd5 Genes in Obese Mice Induced with High-fat Diet

BACKGROUND/AIM

Adipocyte gene expression is altered in obese individuals through multiple metabolic and biochemical pathways. In this study, we aimed to examine the expression of resistin (Retn), amylin (Iapp), and dopamine receptor domain 5 (Drd5) genes previously suggested to contribute to the pathogenesis of obesity, albeit controversially. We also aimed to determine the effects on short and long-term mRNA levels of these genes in obese mice, induced with high-fat diet (HFD).

MATERIALS AND METHODS

Two obesity models were created in our study: group T1 (20 mice) was fed with HFD (60% fat) for 3 months, and group T2 (20 mice) was fed with HFD (60% fat) for 6 months. The control group T0 (20 mice) was fed with a diet of 10% kcal fat supplement for 6 months. At the end of the experiment, their adipose tissues were dissected surgically. Tissue samples of each group were pooled for RNA isolation, cDNA synthesis was carried out and the mRNA levels were examined by quantitative real-time polymerase chain reaction. Serum resistin levels were measured using multiplex bead (luminex) technology for validation.

RESULTS

In T2 mice, the mRNA expression of Retn showed a moderate up-regulation (fold change=8.32; p=0.0019) in the adipose tissues. Iapp expression was also significantly up-regulated (fold change=9.78; p=0.012). Moreover, a 6.36-fold up-regulation for Drd5 was observed in the adipose tissues of T2 mice (p<0.001). At the same time, serum levels of resistin were found to be high in T1 and T2 mice compared to the control group (p<0.001 and p=0.024, respectively).

CONCLUSION

Our study demonstrated that the mRNA levels of the genetic markers considered to play a role in adipogenesis were different in short- and long-term obesity models formed in C57BL/6J mice using HFD.

A Study of Short- and Long-term mRNA Levels of the Retn, Iapp, and Drd5 Genes in Obese Mice Induced with High-fat Diet

BACKGROUND/AIM

Adipocyte gene expression is altered in obese individuals through multiple metabolic and biochemical pathways. In this study, we aimed to examine the expression of resistin (Retn), amylin (Iapp), and dopamine receptor domain 5 (Drd5) genes previously suggested to contribute to the pathogenesis of obesity, albeit controversially. We also aimed to determine the effects on short and long-term mRNA levels of these genes in obese mice, induced with high-fat diet (HFD).

MATERIALS AND METHODS

Two obesity models were created in our study: group T1 (20 mice) was fed with HFD (60% fat) for 3 months, and group T2 (20 mice) was fed with HFD (60% fat) for 6 months. The control group T0 (20 mice) was fed with a diet of 10% kcal fat supplement for 6 months. At the end of the experiment, their adipose tissues were dissected surgically. Tissue samples of each group were pooled for RNA isolation, cDNA synthesis was carried out and the mRNA levels were examined by quantitative real-time polymerase chain reaction. Serum resistin levels were measured using multiplex bead (luminex) technology for validation.

RESULTS

In T2 mice, the mRNA expression of Retn showed a moderate up-regulation (fold change=8.32; p=0.0019) in the adipose tissues. Iapp expression was also significantly up-regulated (fold change=9.78; p=0.012). Moreover, a 6.36-fold up-regulation for Drd5 was observed in the adipose tissues of T2 mice (p<0.001). At the same time, serum levels of resistin were found to be high in T1 and T2 mice compared to the control group (p<0.001 and p=0.024, respectively).

CONCLUSION

Our study demonstrated that the mRNA levels of the genetic markers considered to play a role in adipogenesis were different in short- and long-term obesity models formed in C57BL/6J mice using HFD.

Alabama Children's Body Mass Index, Nutritional Attitudes, and Food Consumption: An Exploratory Analysis

OBJECTIVES

This study had three aims: assess the extent to which middle school children in southern Alabama were classified as overweight or obese; determine the magnitude of the relation between children's attitudes toward healthy eating and their actual dietary choices; and examine the role of race, sex, and ZIP codes on children's eating attitudes and behaviors.

METHODS

Registered dietitians took height and weight measurements of middle school children in southern Alabama to establish body mass index (BMI). Children were given a Likert-type survey with multiple-choice items to assess the study's objectives. Descriptive statistics were generated, and structural equation modeling was used to examine potential moderating effects on the associations between a latent variable of healthy eating attitudes and a latent variable of healthy eating behaviors across race and ethnicity. A series of analyses of variance was used to determine any significant differences in the children's attitudes across schools. The χ² tests were used to examine potential race differences in BMI.

RESULTS

A total of 630 children participated in the study. Their average age was 12 years. More than half (53%) of the children were girls, and more than half (61%) were White. Approximately one-third (29%) identified as Black/African America. A large proportion of children across the sample (42.3%) were classified as overweight or obese. The multigroup structural equation modeling yielded a significant direct path between healthy attitudes and healthy eating behaviors. Healthy eating attitudes strongly predicted intentions toward healthy eating behaviors for children classified as normal weight and for those children classified as overweight or obese. Children's BMI classifications did not differ significantly across schools, race, or sex.

CONCLUSIONS

A large percentage of children in south Alabama were classified as overweight or obese, conditions that are preventable. Moreover, evidence suggests a lack of nutritious food in their diets. Children overall endorsed healthy eating attitudes, and those attitudes were strongly related to healthy food choices; however, their level of healthy food consumption was not related to their BMI classification. Although children in this study were from three schools and represented a variety of racial, sex, and socioeconomic systems, there were more similarities than differences in their healthy eating attitudes or behavior. These similarities highlight the need for research to examine other factors, such as southern culture, as a potential contributor to childhood obesity.

CRISPR/Cas9, the Powerful New Genome-Editing Tool for Putative Therapeutics in Obesity

The molecular technology known as clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) is revolutionizing the field of medical research and deepening our understanding of numerous biological processes. The attraction of CRISPR/Cas9 lies in its ability to efficiently edit DNA or modulate gene expression in living eukaryotic cells and organisms, a technology that was once considered either too expensive or scientifically risky. CRISPR/Cas9 has been successfully applied in agriculture to develop the next generation of disease-resistant plants. Now, the capability of gene editing has been translated to the biomedical area, focusing on the future of medicine faced with drug-resistant microbes by selectively targeting genes involved in antibiotic resistance, for example, or finding the ultimate strategy for cancer or HIV. In this regard, it was recently demonstrated that an injection of cancer-fighting CRISPR-modified white blood cells in a patient suffering from metastatic lung cancer could lead to promising results. Researchers and bioethicists are debating questions about the regulation of CRISPR/Cas9 that must be addressed. While legal challenges surround the use of this technique for genetically modifying cell lines in humans, we review the basic understanding of CRISPR/Cas9 and discuss how this technology could represent a candidate for treatment of non-communicable diseases in nutrition, such as obesity.

Exome Sequencing Identifies Genetic Variants Associated with Circulating Lipid Levels in Mexican Americans: The Insulin Resistance Atherosclerosis Family Study (IRASFS)

Genome-wide association studies have identified numerous variants associated with lipid levels; yet, the majority are located in non-coding regions with unclear mechanisms. In the Insulin Resistance Atherosclerosis Family Study (IRASFS), heritability estimates suggest a strong genetic basis: low-density lipoprotein (LDL, h² = 0.50), high-density lipoprotein (HDL, h² = 0.57), total cholesterol (TC, h² = 0.53), and triglyceride (TG, h² = 0.42) levels. Exome sequencing of 1,205 Mexican Americans (90 pedigrees) from the IRASFS identified 548,889 variants and association and linkage analyses with lipid levels were performed. One genome-wide significant signal was detected in APOA5 with TG (rs651821, P_TG = 3.67 × 10^-10, LOD_TG = 2.36, MAF = 14.2%). In addition, two correlated SNPs (r² = 1.0) rs189547099 (P_TG = 6.31 × 10^-08, LOD_TG = 3.13, MAF = 0.50%) and chr4:157997598 (P_TG = 6.31 × 10^-08, LOD_TG = 3.13, MAF = 0.50%) reached exome-wide significance (P < 9.11 × 10^-08). rs189547099 is an intronic SNP in FNIP2 and SNP chr4:157997598 is intronic in GLRB. Linkage analysis revealed 46 SNPs with a LOD > 3 with the strongest signal at rs1141070 (LOD_LDL = 4.30, P_LDL = 0.33, MAF = 21.6%) in DFFB. A total of 53 nominally associated variants (P < 5.00 × 10^-05, MAF ≥ 1.0%) were selected for replication in six Mexican-American cohorts (N = 3,280). The strongest signal observed was a synonymous variant (rs1160983, P_LDL = 4.44 × 10^-17, MAF = 2.7%) in TOMM40. Beyond primary findings, previously reported lipid loci were fine-mapped using exome sequencing in IRASFS. These results support that exome sequencing complements and extends insights into the genetics of lipid levels.

Family history of diabetes and its relationship with insulin secretion and insulin sensitivity in Iraqi immigrants and native Swedes: a population-based cohort study

AIMS

Middle Eastern immigrants to western countries are at high risk of developing type 2 diabetes. However, the heritability and impact of first-degree family history (FH) of type 2 diabetes on insulin secretion and action have not been adequately described.

METHODS

Citizens of Malmö, Sweden, aged 30-75 years born in Iraq or Sweden were invited to participate in this population-based study. Insulin secretion (corrected insulin response and oral disposition index) and action (insulin sensitivity index) were assessed by oral glucose tolerance tests.

RESULTS

In total, 45.7% of Iraqis (616/1348) and 27.4% of native Swedes (201/733) had FH in parent(s), sibling(s) or single parent and sibling, i.e., FH+. Approximately 8% of Iraqis and 0.7% of Swedes had ≥ 3 sibling(s) and parent(s) with diabetes, i.e., FH++. Irrespective of family size, prediabetes and diabetes increased with family burden (FH- 29.4%; FH+ 38.8%; FH++ 61.7%) without significant differences across ethnicities. With increasing level of family burden, insulin secretion rather than insulin action decreased. Individuals with a combination of ≥ 3 siblings and parents with diabetes presented with the lowest levels of insulin secretion.

CONCLUSIONS

The Iraqi immigrant population often present with a strong familial burden of type 2 diabetes with the worst glycemic control and highest diabetes risk in individuals with ≥ 3 siblings and parents with diabetes. Our data show that in a population still free from diabetes familial burden influences insulin secretion to a higher degree than insulin action and may be a logical target for intervention.

Genetic analysis of very obese children with autism spectrum disorder

Autism spectrum disorder (ASD) is defined by the triad of deficits in social interactions, deficits in communication, and repetitive behaviors. Common co-morbidities in syndromic forms of ASD include intellectual disability, seizures, and obesity. We asked whether very obese children with ASD had different behavioral, physical and genetic characteristics compared to children with ASD who were not obese. We found that very obese children with ASD had significantly poorer scores on standardized behavioral tests. Very obese boys with ASD had lower full scale IQ and increased impairments with respect to stereotypies, communication and social skills. Very obese girls with ASD had increased impairments with respect to irritability and oppositional defiant behavior. We identified genetic lesions in a subset of the children with ASD and obesity and attempted to identify enriched biological pathways. Our study demonstrates the value of identifying co-morbidities in children with ASD as we move forward towards understanding the biological processes that contribute to this complex disorder and prepare to design customized treatments that target the diverse genetic lesions present in individuals with ASD.

Postpartum Mothers' Experiences With Newborn Weight Checks in the Home

Few researchers have examined the perspectives of breastfeeding mothers about using a pediatric scale in the home to monitor infant weight. A cross sectional design was used to measure helpfulness, impact on newborn feeding, and confidence among mothers who used a digital scale to monitor newborn weight. Women (N = 69) who had given birth in a community hospital in the Northeast region of the United States used a pediatric scale in the home daily for 2 weeks after birth. An online survey determined helpfulness of the scale, if use of the scale impacted feedings, and confidence in breastfeeding. Using a pediatric scale to monitor newborn weight was very helpful (n = 49; 71%); it was most helpful for primiparous women (P < .016). Feeding frequency often changed on the basis of neonatal weight (n = 27; 39%) but only 9% (n = 6) changed the type of milk fed. Confidence in breastfeeding increased in 90% (n = 62) of participants. A pediatric scale used in the home to monitor newborn weight is helpful for breastfeeding, especially for primiparous women. Use of the scale may increase maternal confidence in breastfeeding and help guide decisions about feeding frequency.

GNB3 overexpression causes obesity and metabolic syndrome

The G-protein beta subunit 3 (GNB3) gene has been implicated in obesity risk; however, the molecular mechanism of GNB3-related disease is unknown. GNB3 duplication is responsible for a syndromic form of childhood obesity, and an activating DNA sequence variant (C825T) in GNB3 is also associated with obesity. To test the hypothesis that GNB3 overexpression causes obesity, we created bacterial artificial chromosome (BAC) transgenic mice that carry an extra copy of the human GNB3 risk allele. Here we show that GNB3-T/+ mice have increased adiposity, but not greater food intake or a defect in satiety. GNB3-T/+ mice have elevated fasting plasma glucose, insulin, and C-peptide, as well as glucose intolerance, indicating type 2 diabetes. Fasting plasma leptin, triglycerides, cholesterol and phospholipids are elevated, suggesting metabolic syndrome. Based on a battery of behavioral tests, GNB3-T/+ mice did not exhibit anxiety- or depressive-like phenotypes. GNB3-T/+ and wild-type animals have similar activity levels and heat production; however, GNB3-T/+ mice exhibit dysregulation of acute thermogenesis. Finally, Ucp1 expression is significantly lower in white adipose tissue (WAT) in GNB3-T/+ mice, suggestive of WAT remodeling that could lead to impaired cellular thermogenesis. Taken together, our study provides the first functional link between GNB3 and obesity, and presents insight into novel pathways that could be applied to combat obesity and type 2 diabetes.

Maternal inheritance of BDNF deletion, with phenotype of obesity and developmental delay in mother and child

Childhood obesity is a significant world health problem. Understanding the genetic and environmental factors contributing to the development of obesity in childhood is important for the rational design of strategies for obesity prevention and treatment. Brain-derived neurotrophic factor (BDNF) plays an important role in the growth and development of the central nervous system, there is also an evidence that BDNF plays a role in regulation of appetite. Disruption of the expression of this gene in a child has been previously reported to result in a phenotype of severe obesity, hyperphagia, impaired cognitive function, and hyperactivity. We report a mother and child, both with micro-deletions encompassing the BDNF gene locus, who both have obesity and developmental delay, although without hyperactivity. This report highlights the maternal inheritance of a rare genetic cause of childhood obesity.

Gene-nutrient interactions and susceptibility to human obesity

A large number of genome-wide association studies, transferability studies, and candidate gene studies performed in diverse populations around the world have identified gene variants that are associated with common human obesity. The mounting evidence suggests that these obesity gene variants interact with multiple environmental factors and increase susceptibility to this complex metabolic disease. The objective of this review article is to provide concise and updated information on energy balance, heritability of body weight, origins of gene variants, and gene-nutrient interactions in relation to human obesity. It is proposed that knowledge of these related topics will provide valuable insight for future preventative lifestyle intervention using targeted nutritional and medicinal therapies.

High Fat Diet with a High Monounsaturated Fatty Acid and Polyunsaturated/Saturated Fatty Acid Ratio Suppresses Body Fat Accumulation and Weight Gain in Obese Hamsters

The aim of this study was to investigate the effect of a high fat diet with experimental oil consisting of 60% MUFAs (monounsaturated fatty acids) with a P/S ratio of 5 on fat deposition and lipid metabolism in obese hamsters. Hamsters were randomly assigned to a control group and a diet-induced obesity group for nine weeks. Then an additional eight-week experimental period began, during which obese hamsters were randomly divided into three groups and fed different amounts of the experimental oil mixture in their diets as follows: 5%, 15%, and 20% w/w (OB-M5, OB-M15, and OB-M20 groups, respectively). The results showed that the OB-M15 and OB-M20 groups had significantly lower blood cholesterol and higher insulin levels. Compared to the control group, the three obese groups exhibited higher hepatic fatty acid synthase activity; however, the acyl-CoA oxidase activities were also enhanced. Although dietary fat content differed, there were no differences in energy intake, final body weights, and epididymal fat weights among the four groups. These results suggest that regardless of whether the specimens had a high fat intake or not, dietary fat containing high MUFAs with a high P/S ratio had beneficial effects on maintaining blood lipid profiles and may not result in body fat accumulation in obese hamsters, possibly by promoting lipolytic enzyme activities.

DETECTION OF RS9939609 POLYMORPHISM OF FTO GENE AND RS324011 POLYMORPHISM OF STAT6 GENE AND SEVERITY DEGREE OF BRONCHIAL ASTHMA ASSOCIATED WITH OBESITY

The aim of this research was to analyze the distribution of FTO and STAT6 genes polymorphism in patients with bronchial asthma (BA), associated with obesity (Ob) depending on the main disease severity degree. Materials and methods. The study included 117 patients 18–48 years old, divided in 3 groups. The main group (bronchial asthma, associated with obesity) included 57 patients, two groups of comparison – 30 patients with the diagnosis BA and a normal body weight, and 30 patients with obesity, but without the pathology of the bronchopulmonary system. The general genomic DNA was extracted from blood according to the standard protocol. The genetic typing was realized by the method of allele-specific amplification with the detection of results in the real time regime using TaqMan-probes, complementary to polymorphic parts of DNA. The detection of deletions in FTO and STAT 6 genes was realized by the method of polymerase chain reaction (PCR) using specific primers. Results. In the main group, among patients with BA and Ob, carriers of Т/Т genotype were 36,84 %, Т/А – 45,61 %, А/А – 17,55 % against 40 %, 60 % and 0 % respectively in PHP group by FTO gene. Carriers of С/С genotype in the main group were 38,6 %, С/Т – 35,09 %, Т/Т – 26,31 % against 40 %, 55 % and 5 % respectively in PHP group by STAT6 gene. In the main group the light persisting BA was diagnosed in 20,0 % of cases, middle severity – in 60,0 % and severe – in 20,0 % of patients. In the group of comparison this disease severity was observed in 17,7 %, 66,5 % and 15,8 % of observations, respectively. Conclusions. So, among patients with BA, associated with Ob with the middle and severe course of asthma the percent of heterozygous (Т/А) and mutant carriers (А/А) rs9939609 polymorphism of FTO gene is higher than at the light course. The analogous situation is observed at the study of rs324011 polymorphism of STAT6 (C2892T) gene among this category of patients. So, the determination of FTO and STAT6 genes polymorphism in patients with BA, associated with Ob, can be considered as a marker of the more severe course of asthma.

Transcriptional responses of ecologically diverse Drosophila species to larval diets differing in relative sugar and protein ratios

We utilized three ecologically diverse Drosophila species to explore the influence of ecological adaptation on transcriptomic responses to isocaloric diets differing in their relative proportions of protein to sugar. Drosophila melanogaster, a cosmopolitan species that breeds in decaying fruit, exemplifies individuals long exposed to a Western diet higher in sugar, while the natural diet of the cactophilic D. mojavensis, is much lower in carbohydrates. Drosophila arizonae, the sister species of D. mojavensis, is largely cactophilic, but also utilizes rotting fruits that are higher in sugars than cacti. We exposed third instar larvae for 24 hours to diets either (1) high in protein relative to sugar, (2) diets with equal amounts of protein and sugar, and (3) diets low in protein but high in sugar. As we predicted, based upon earlier interspecific studies of development and metabolism, the most extreme differences in gene expression under different dietary conditions were found in D. mojavensis followed by D. arizonae. No differential expression among diets was observed for D. melanogaster, a species that survives well under all three conditions, with little impact on its metabolism. We suggest that these three species together provide a model to examine individual and population differences in vulnerability to lifestyle-associated health problems such as metabolic syndrome and diabetes.

Cultural Variables Underlying Obesity in Latino Men: Design, Rationale and Participant Characteristics from the Latino Men's Health Initiative

Overweight and obesity are associated with significant health problems and rates of obesity are high among Latino men. This paper describes the design, rationale and participant characteristics of the key demographic variables assessed in an NIH-funded study (R21-CA143636) addressing culture and several obesity-related variables (diet, physical activity, and body image) among Mexican and Puerto Rican men using a community-based participatory research framework. Participants completed objective measures (height, weight, body fat, hip, waist), a health and culture interview, a diet questionnaire, and used an accelerometer to measure their level of physical activity. A total of 203 participants completed the measures and the health and culture interview and 193 completed all study components. Puerto Ricans were older than Mexicans (p < .0001) and there were significant differences in marital status (p < .05), country of birth (p < .05), smoking (p < .05) and work status (p < .001). There were no significant differences in religion, education, health insurance, Body Mass Index, body fat, hip and waist measurements, and the language preference of the interview. Results have implications for the development of a future intervention that incorporates the role of cultural factors into a community participatory obesity intervention for Latino men.

Genotype-covariate interaction effects and the heritability of adult body mass index

Obesity is a worldwide epidemic, with major health and economic costs. Here we estimate heritability for body mass index (BMI) in 172,000 sibling pairs and 150,832 unrelated individuals and explore the contribution of genotype-covariate interaction effects at common SNP loci. We find evidence for genotype-age interaction (likelihood ratio test (LRT) = 73.58, degrees of freedom (df) = 1, P = 4.83 × 10^-18), which contributed 8.1% (1.4% s.e.) to BMI variation. Across eight self-reported lifestyle factors, including diet and exercise, we find genotype-environment interaction only for smoking behavior (LRT = 19.70, P = 5.03 × 10^-5 and LRT = 30.80, P = 1.42 × 10^-8), which contributed 4.0% (0.8% s.e.) to BMI variation. Bayesian association analysis suggests that BMI is highly polygenic, with 75% of the SNP heritability attributable to loci that each explain <0.01% of the phenotypic variance. Our findings imply that substantially larger sample sizes across ages and lifestyles are required to understand the full genetic architecture of BMI.

[Obesities: What's new in 2016?]

Since 1997, the World Health Organisation considered obesity, defined as an excess of fat mass, as a disease. Many plans have been set up to fight against obesity in industrialised countries. However, the prevalence of obesity is still increasing. The goal of this paper is to report some of the major scientific publications in terms of epidemiology, physiopathology or therapeutic in the field of obersity mainly published during year 2015-2016 or presented at ENDO meeting 2016.

Whole-Genome Sequencing Coupled to Imputation Discovers Genetic Signals for Anthropometric Traits

Deep sequence-based imputation can enhance the discovery power of genome-wide association studies by assessing previously unexplored variation across the common- and low-frequency spectra. We applied a hybrid whole-genome sequencing (WGS) and deep imputation approach to examine the broader allelic architecture of 12 anthropometric traits associated with height, body mass, and fat distribution in up to 267,616 individuals. We report 106 genome-wide significant signals that have not been previously identified, including 9 low-frequency variants pointing to functional candidates. Of the 106 signals, 6 are in genomic regions that have not been implicated with related traits before, 28 are independent signals at previously reported regions, and 72 represent previously reported signals for a different anthropometric trait. 71% of signals reside within genes and fine mapping resolves 23 signals to one or two likely causal variants. We confirm genetic overlap between human monogenic and polygenic anthropometric traits and find signal enrichment in cis expression QTLs in relevant tissues. Our results highlight the potential of WGS strategies to enhance biologically relevant discoveries across the frequency spectrum.

Recent progress in genetics, epigenetics and metagenomics unveils the pathophysiology of human obesity

In high-, middle- and low-income countries, the rising prevalence of obesity is the underlying cause of numerous health complications and increased mortality. Being a complex and heritable disorder, obesity results from the interplay between genetic susceptibility, epigenetics, metagenomics and the environment. Attempts at understanding the genetic basis of obesity have identified numerous genes associated with syndromic monogenic, non-syndromic monogenic, oligogenic and polygenic obesity. The genetics of leanness are also considered relevant as it mirrors some of obesity's aetiologies. In this report, we summarize ten genetically elucidated obesity syndromes, some of which are involved in ciliary functioning. We comprehensively review 11 monogenic obesity genes identified to date and their role in energy maintenance as part of the leptin-melanocortin pathway. With the emergence of genome-wide association studies over the last decade, 227 genetic variants involved in different biological pathways (central nervous system, food sensing and digestion, adipocyte differentiation, insulin signalling, lipid metabolism, muscle and liver biology, gut microbiota) have been associated with polygenic obesity. Advances in obligatory and facilitated epigenetic variation, and gene-environment interaction studies have partly accounted for the missing heritability of obesity and provided additional insight into its aetiology. The role of gut microbiota in obesity pathophysiology, as well as the 12 genes associated with lipodystrophies is discussed. Furthermore, in an attempt to improve future studies and merge the gap between research and clinical practice, we provide suggestions on how high-throughput '-omic' data can be integrated in order to get closer to the new age of personalized medicine.

DRD2: Bridging the Genome and Ingestive Behavior

Recent work highlights the importance of genetic variants that influence brain structure and function in conferring risk for polygenic obesity. The neurotransmitter dopamine (DA) has a pivotal role in energy balance by integrating metabolic signals with circuits supporting cognitive, perceptual, and appetitive functions that guide feeding. It has also been established that diet and obesity alter DA signaling, leading to compulsive-like feeding and neurocognitive impairments. This raises the possibility that genetic variants that influence DA signaling and adaptation confer risk for overeating and cognitive decline. Here, we consider the role of two common gene variants, FTO and TaqIA rs1800497 in driving gene × environment interactions promoting obesity, metabolic dysfunction, and cognitive change via their influence on DA receptor subtype 2 (DRD2) signaling.

DNA Methylation Profiles of Blood Cells Are Distinct between Early-Onset Obese and Control Individuals

Obesity is a highly prevalent, chronic disorder that has been increasing in incidence in young patients. Both epigenetic and genetic aberrations may play a role in the pathogenesis of obesity. Therefore, in-depth epigenomic and genomic analyses will advance our understanding of the detailed molecular mechanisms underlying obesity and aid in the selection of potential biomarkers for obesity in youth. Here, we performed microarray-based DNA methylation and gene expression profiling of peripheral white blood cells obtained from six young, obese individuals and six healthy controls. We observed that the hierarchical clustering of DNA methylation, but not gene expression, clearly segregates the obese individuals from the controls, suggesting that the metabolic disturbance that occurs as a result of obesity at a young age may affect the DNA methylation of peripheral blood cells without accompanying transcriptional changes. To examine the genome-wide differences in the DNA methylation profiles of young obese and control individuals, we identified differentially methylated CpG sites and investigated their genomic and epigenomic contexts. The aberrant DNA methylation patterns in obese individuals can be summarized as relative gains and losses of DNA methylation in gene promoters and gene bodies, respectively. We also observed that the CpG islands of obese individuals are more susceptible to DNA methylation compared to controls. Our pilot study suggests that the genome-wide aberrant DNA methylation patterns of obese individuals may advance not only our understanding of the epigenomic pathogenesis but also early screening of obesity in youth.

Gut microbiome diversity and high-fibre intake are related to lower long-term weight gain

Background:

Cross-sectional studies suggest that the microbes in the human gut have a role in obesity by influencing the human body’s ability to extract and store calories. The aim of this study was to assess if there is a correlation between change in body weight over time and gut microbiome composition.

Methods:

We analysed 16S ribosomal RNA gene sequence data derived from the faecal samples of 1632 healthy females from TwinsUK to investigate the association between gut microbiome measured cross-sectionally and longitudinal weight gain (adjusted for caloric intake and baseline body mass index). Dietary fibre intake was investigated as a possible modifier.

Results:

Less than half of the variation in long-term weight change was found to be heritable (h²=0.41 (0.31, 0.47)). Gut microbiota diversity was negatively associated with long-term weight gain, whereas it was positively correlated with fibre intake. Nine bacterial operational taxonomic units (OTUs) were significantly associated with weight gain after adjusting for covariates, family relatedness and multiple testing (false discovery rate <0.05). OTUs associated with lower long-term weight gain included those assigned to Ruminococcaceae (associated in mice with improved energy metabolism) and Lachnospiraceae. A Bacterioides species OTU was associated with increased risk of weight gain but this appears to be driven by its correlation with lower levels of diversity.

Conclusions:

High gut microbiome diversity, high-fibre intake and OTUs implicated in animal models of improved energy metabolism are all correlated with lower term weight gain in humans independently of calorie intake and other confounders.

Metabolism disrupting chemicals and metabolic disorders

The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

A Novel Single Nucleotide T980C Polymorphism in the Human Carboxypeptidase E Gene Results in Loss of Neuroprotective Function

Report of a human with a homozygous truncating null mutation of the Carboxypeptidase E (CPE) gene with endocrinological and neurological deficits prompted us to search for other mutations in the human CPE gene that might be linked to disease. We searched an EST database and identified from a small population of patients, a novel T to C single nucleotide polymorphism (SNP) in the CPE gene at bp980 of exon 4, herein called TC-CPE. This introduces a tryptophan to arginine (W235R) mutation in the catalytic domain of human CPE protein. Over-expression of TC-CPE in N2A cells, a neuroendocrine cell line, showed that it was synthesized, but was found in lesser amounts compared to over-expressed WT-CPE in these cells. Furthermore, TC-CPE was secreted poorly from these N2A cells. The levels of TC-CPE were significantly increased after the N2A cells were treated with MG132 (a proteasome inhibitor), suggesting that TC-CPE was targeted to proteasomes for degradation in N2A cells. In addition, TC-CPE induced ER stress as demonstrated by the increased expression of CHOP in N2A cells. Double labeling of CPE and calnexin (and ER marker) suggested the accumulation of TC-CPE in the ER, and the accumulation appears to be enhanced by the treatment of MG132 in the cells. Moreover, the secreted levels of TC-CPE were not affected by the treatment of MG132 in the cells. Over-expression studies revealed that while N2A cells transfected with WT-CPE showed reduced cytotoxicity when challenged with H₂O₂ compared to cells expressing an empty vector, cells transfected with TC-CPE had no effect. Furthermore, WT-CPE condition medium showed protective effect against oxidative stress, but not TC-CPE condition medium. Although co-expression of WT-CPE and TC-CPE in N2A cells resulted in the reduction in secretion of WT-CPE, co-expression of WT-CPE and TC-CPE did not significantly affect the protective effect of WT-CPE. Taken together, we have identified a novel SNP in the CPE gene which results in the loss of its neuroprotective function in cells and may confer neurological disorders in humans.

Glucagon-like peptide 1 in the pathophysiology and pharmacotherapy of clinical obesity

Though the pathophysiology of clinical obesity is undoubtedly multifaceted, several lines of clinical evidence implicate an important functional role for glucagon-like peptide 1 (GLP-1) signalling. Clinical studies assessing GLP-1 responses in normal weight and obese subjects suggest that weight gain may induce functional deficits in GLP-1 signalling that facilitates maintenance of the obesity phenotype. In addition, genetic studies implicate a possible role for altered GLP-1 signalling as a risk factor towards the development of obesity. As reductions in functional GLP-1 signalling seem to play a role in clinical obesity, the pharmacological replenishment seems a promising target for the medical management of obesity in clinical practice. GLP-1 analogue liraglutide at a high dose (3 mg/d) has shown promising results in achieving and maintaining greater weight loss in obese individuals compared to placebo control, and currently licensed anti-obesity medications. Generally well tolerated, provided that longer-term data in clinical practice supports the currently available evidence of superior short- and long-term weight loss efficacy, GLP-1 analogues provide promise towards achieving the successful, sustainable medical management of obesity that remains as yet, an unmet clinical need.