Genetic determinants of obesity and related vascular diseases

Association of childhood obesity on retinal microvasculature and the role of biochemical markers for its early detection

BACKGROUND

Childhood obesity is a growing public health concern, associated with several systemic disorders including changes in retinal microvasculature. This study aims to assess the relationship between body composition, biochemical markers, and retinal microvascular changes in obese children.

METHODS

In this cross-sectional study, 45 overweight and obese children and 46 age- and sex-matched healthy individuals were evaluated. In addition to physical examination, anthropometric measurements were obtained using a body composition analyzer. A comprehensive ophthalmic assessment was conducted for all participants, which included advanced optical biometry, autorefractometry, visual acuity testing, and slit-lamp examination. Retinal microvasculature was assessed using optical coherence tomography angiography (OCT-A). Biochemical markers, including lipid profile, liver function tests, and CRP (as marker of inflammation), were also analyzed.

RESULTS

The mean ages were 10.18 and 9.40 years in the obese/overweight and normal weight groups, respectively. Increased foveal thickness (p = 0.04) and foveal vessel density (p = 0.01) in the superficial capillary plexus, and decreased vessel density in the inferior parafoveal region of the deep capillary plexus (p = 0.03) were observed in obese/overweight children. Adjusted and crude regression analysis showed significant associations between body mass index, percent body fat, fasting blood glucose, and serum alanine transaminase levels with foveal vessel density, as well as between body mass index and serum triglycerides levels with foveal thickness.

CONCLUSIONS

Our findings suggest that childhood obesity is associated with significant alterations in retinal microvasculature. We propose that retinal health assessments and biochemical evaluations be considered in the clinical management of obese children.

The biology of mitochondrial carrier homolog 2

The mitochondrial carrier system is in charge of small molecule transport between the mitochondria and the cytoplasm as well as being an integral portion of the core mitochondrial function. One member of the mitochondrial carrier family of proteins, mitochondrial carrier homolog 2 (MTCH2), is characterized as a critical mitochondrial outer membrane protein insertase participating in mitochondrial homeostasis. Accumulating evidence demonstrate that MTCH2 is integrally linked to cell death and mitochondrial metabolism, and its genetic alterations cause a variety of disease phenotypes, ranging from obesity, Alzheimer's disease, and tumor. To provide a comprehensive insight into the current understanding of MTCH2, we present a detailed description of the physiopathological functions of MTCH2, ranging from apoptosis, mitochondrial dynamics, and metabolic homeostasis regulation. Moreover, we summarized the impact of MTCH2 in human diseases, and highlighted tumors, to assess the role of MTCH2 mutations or variable expression on pathogenesis and target therapeutic options.

Role of FTO and MC4R Polymorphisms in Escalating Obesity and Their Indirect Association With Risk of T2D in Indian Population

INTRODUCTION

Obesity plays a pivotal role in the development of metabolic syndrome-excessive body fat, spikes in blood glucose levels and hypertension-and ultimately leads to cardiovascular diseases and type 2 diabetes (T2D), if left unattended. The present study aimed to investigate the associated risk of T2D with obesity risk alleles of fat mass and obesity-associated (FTO) and melanocortin 4 receptor (MC4R) genes.

METHODS

The study includes 400 subjects (300 T2D diabetic cases and 100 healthy controls). Genetic analysis was done by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods.

RESULTS

The findings of the study show no significant increase in odds of diabetes associated with the prevalence of FTO and MC4R minor alleles. Rare allele frequencies for "A" of FTO rs9939609 were 0.34 and 0.30 in cases and controls, respectively. Rare allele frequencies for A of MC4R rs12970134 were found to be more common in controls (0.45) than cases (0.41), but the difference was insignificant (p 0.246); however, an increase in body weight with the presence of allele "A" of the FTO gene (p value < 0.001) was found, indicating indirect involvement in the development of T2D. In addition, these were also correlated with the demographic/lifestyle and clinico-pathological parameters between T2D cases and controls. We found that T2D patients with a history of smoking and high consumption of alcohol, fast foods and sweetened beverages are at high risk of T2D compared to healthy controls (p  < 0.01*).

CONCLUSION

The present study concludes that there is no direct association of rs9939609 of the FTO gene with the occurrence of diabetes in the Indian population, but its role in T2D development cannot be overlooked altogether. Furthermore, we conclude that the rs9939609 of FTO carries a potential risk of obesity and because of this FTO rs9939609 T > A is widely considered an obesity-associated allele/single-nucleotide polymorphism (SNP).

The impact of obesity to antioxidant defense parameters in adolescents with increased cardiovascular risk

Background

The goal of this study was to assess the oxidative stress status through the values of antioxidant defense parameters: superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and total antioxidant status (TAS), as well as cardiovascular risk factors (total cholesterol, LDL-cholesterol, VLDL-cholesterol, non-HDL-cholesterol and triglycerides), anthropometric parameters (Body mass index-BMI, waist circumference-WC, hipp circumferemce-HC, waist-to-hipp ratio-WHR and inflammatory markers (high sensitive C-reactive protein) in a group of obese adolescents.

Methods

A total of 238 students of both sexes, age of 22.32 ± 1.85 yr. were included in the study. According to the values of BMI lower and higher than 25 kg/m2 and WC higher and lower than 94 cm (males)/80 cm (females) the tested group of students was divided into 2 subgroups: Group 1 (increased risk for CVD) and Group 2 (lower risk for CVD).

Results

Significantly reduced SOD and GPx with increased GR, TAS, inflammatory and lipoprotein parameters were obtained in Group 1 compared to Group 2. Significant positive association of hsCRP (OR:1.41; 95%CI 1.08-1.83; P=0.007), TAS (OR:827.2; 95%CI 19.27-35498; P=0.007) and GR (OR:1.13; 95%CI 1.05-1.21; P=0.002) and negative association of GPx (OR:0.97; 95%CI 0.94-1.003; P=0.043) and HDL-cholesterol (OR:0.41; 95%CI 0.176-0.963; P=0.0014) with cardiovascular risk factors were found in obese students. According to the ROC analysis GR>44.8 U/L, TAS>1.35 mmol/L, hsCRP>1.71 mg/L and HDL-cholesterol <1.13 mmol/L have sufficient predictive ability for cardiovascular disease in obese students.

Conclusions

Significant association of antioxidant defense parameters with anthropometric, lipid and inflammatory markers in obese students with increased cardiovascular risk suggest that screening of these parameters is necessary and highly recommended.

Screening of 31 genes involved in monogenic forms of obesity in 23 Pakistani probands with early-onset childhood obesity: a case report

BACKGROUND

Consanguine families display a high degree of homozygosity which increases the risk of family members suffering from autosomal recessive disorders. Thus, homozygous mutations in monogenic obesity genes may be a more frequent cause of childhood obesity in a consanguineous population.

METHODS

We identified 23 probands from 23 Pakistani families displaying autosomal recessive obesity. We have previously excluded mutations in MC4R, LEP and LEPR in all probands. Using a chip-based, target-region capture array, 31 genes involved in monogenic forms of obesity, were screened in all probands.

RESULTS

We identified 31 rare non-synonymous possibly pathogenic variants (28 missense and three nonsense) within the 31 selected genes. All variants were heterozygous, thus no homozygous pathogenic variants were found. Two of the rare heterozygous nonsense variants identified (p.R75X and p.R481X) were found in BBS9 within one proband, suggesting that obesity is caused by compound heterozygosity. Sequencing of the parents supported the compound heterozygous nature of obesity as each parent was carrying one of the variants. Subsequent clinical investigation strongly indicated that the proband had Bardet-Biedl syndrome.

CONCLUSIONS

Mutation screening in 31 genes among probands with severe early-onset obesity from Pakistani families did not reveal the presence of homozygous obesity causing variants. However, a compound heterozygote carrier of BBS9 mutations was identified, indicating that compound heterozygosity must not be overlooked when investigating the genetic etiology of severe childhood obesity in populations with a high degree of consanguinity.

Trend in overweight and obesity among women of reproductive age in Uganda: 1995-2016

Countries in Sub-Saharan Africa (SSA) are experiencing rising burdens of overweight/obesity and associated non-communicable diseases. As in other developing regions, this epidemiological transition in African countries is believed to be resulting from changes in dietary, sociodemographic structure and lifestyle factors. To date, not much is known about the prevalence and sociodemographic patterns of overweight/obesity in Uganda, especially among women of reproductive age. Therefore, this study aimed to address this research gap by using nationally representative data on women of this age group in Uganda.

METHODS

This study involved analysis of cross-sectional data on 19,395 women aged between 15 and 49 years from Uganda Demographic and Health Survey for the years 1995-2016. Overweight/obesity was measured using body mass index as per World Health Organization guidelines, and logistic regression methods were used to identify the sociodemographic predictors.

RESULTS

There has a been significant rise in the prevalence of overweight (9.77% in 1995 vs. 16.21% in 2016) and obesity (1.99% in 1995 vs. 6.21% in 2016) since the first survey in 1995, with the most noticeable increase occurring in the central region that accounted for a combined prevalence of 17.22% in 1995 compared with 37. 21% in 2016. Multivariate analysis showed an increased likelihood of having overweight/obesity among women who live in the urban areas, have primary and above primary education, from non-poor households and users of radio and TV.

CONCLUSION

During the last two decades, there has been a slow but steady rise in the prevalence of overweight and obesity among women of reproductive age in Uganda. The present findings highlight the need for an enhanced attention on growing overweight/obesity within the broader goal improving maternal and child health in the country.

Regulation of alternative splicing in obesity-induced hypertension

Obesity is the result of genetics which predisposes an individual to obesity and environmental factors, resulting in excessive weight gain. A well-established linear relationship exists between hypertension and obesity. The combined burden of hypertension and obesity poses significant health and economic challenges. Many environmental factors and genetic traits interact to contribute to obesity-linked hypertension. These include excess sodium re-absorption or secretion by the kidneys, a hypertensive shift of renal-pressure and activation of the sympathetic nervous system. Most individuals suffering from hypertension need drugs in order to treat their raised blood pressure, and while a number of antihypertensive therapeutic agents are currently available, 50% of cases remain uncontrolled. In order to develop new and effective therapeutic agents combating obesity-induced hypertension, a thorough understanding of the molecular events leading to adipogenesis is critical. With the advent of whole genome and exome sequencing techniques, new genes and variants which can be used as markers for obesity and hypertension are being identified. This review examines the role played by alternative splicing (AS) as a contributing factor to the metabolic regulation of obesity-induced hypertension. Splicing mutations constitute at least 14% of the disease-causing mutations, thus implicating polymorphisms that effect splicing as indicators of disease susceptibility. The unique transcripts resulting from the alternate splicing of mRNA encoding proteins that play a key role in contributing to obesity would be vital to gain a proper understanding of the genetic causes of obesity. A greater knowledge of the genetic basis for obesity-linked hypertension will assist in the development of appropriate diagnostic tests as well as the identification of new personalized therapeutic targets against obesity-induced hypertension.

[Anti-obesogenic effect of apple cider vinegar in rats subjected to a high fat diet]

AIM OF THE STUDY

The search of new anti-obesogenic treatments based on medicinal plants without or with minimal side effects is a challenge. In this context, the present study was conducted to evaluate the anti-obesogenic effect of apple cider vinegar (ACV) in Wistar rats subjected to a high fat diet.

MATERIALS AND METHODS

Eighteen male Wistar rats (140±5g) were divided into 3 three equal groups. A witness group submitted to standard laboratory diet and two groups subjected to a high fat diet (cafeteria diet); one receives a daily gavage of apple cider vinegar (7mL/kg/d) for 30 days. Throughout the experiment monitoring the nutritional assessment, anthropometric and biochemical parameters is achieved.

RESULTS

In the RCV vs RC group, we observed a highly significant decrease (P<0.001) in body weight and food intake. On the other hand, the VCP decreases very significantly different anthropometric parameters: BMI (P<0.01), chest circumference and abdominal circumference (P<0.001), decreases serum glucose levels (26.83%) and improves the serum lipid profile by reducing plasma levels of total cholesterol (34.29%), TG (51.06%), LDL-c (59.15%), VLDL (50%) and the total lipid (45.15%), and increasing HDL-c (39.39%), thus offering protection against oatherogenic risk (61.62%).

CONCLUSION

This preliminary study indicates that the metabolic disorders caused by high fat diet (cafeteria) are thwarted by taking apple cider vinegar which proves to have a satiating effect, antihyperlipidemic and hypoglycemic effects, and seems prevent the atherogenic risk.

Genome-Wide Gene by Environment Interaction Analysis Identifies Common SNPs at 17q21.2 that Are Associated with Increased Body Mass Index Only among Asthmatics

Asthmatics have an increased risk of being overweight/obese. Although the underlying mechanisms of this are unclear, genetic factors are believed to play an essential role. To identify common genetic variants that are associated with asthma-related BMI increase, we performed a genome-wide gene by environment (asthma) interaction analysis for the outcome of BMI in the Multi-Ethnic Study of Atherosclerosis (MESA) study (N = 2474 Caucasians, 257 asthmatics), and replicated findings in the Framingham Heart Study (FHS) offspring cohort (N = 1408 Caucasians, 382 asthmatics). The replicable tagging SNP, rs2107212, was further examined in stratified analyses. Seven SNPs clustered in 17q21.2 were identified to be associated with higher BMI among asthmatics (interaction p < 5×10⁻⁷ in MESA and p < 0.05 in FHS). In both MESA and FHS asthmatics, subjects carrying the A allele on rs2107212 had significantly higher odds of obesity than non-carriers, which was not the case for non-asthmatics. We further examined BMI change subsequent to asthma diagnosis over a period of 26 years in FHS and demonstrated greater BMI increase among asthmatics compared to non-asthmatics. Asthmatics carrying the A allele at rs2107212 had significantly greater net BMI increase over the 26-year period compared to non-asthmatics. In this study, we found that common genetic variants on 17q21.2 are associated with post-asthma BMI increase among Caucasians. This finding will help elucidate pathways involved in the comorbidity of asthma and obesity.

An economy of scales: A selective review of obesity's economic causes, consequences, and solutions

This paper reviews the economic research on obesity, covering topics such as the measurement of, and trends in, obesity, the economic causes of obesity (e.g. the monetary price and time cost of food, food assistance programs, income, education, macroeconomic conditions, and peer effects), and the economic consequences of obesity (e.g. lower wages, a lower probability of employment, and higher medical care costs). It also examines the extent to which obesity imposes negative externalities, and economic interventions that could potentially internalize such externalities, such as food taxes, subsidies for school-based physical activity programs, and financial rewards for weight loss. It discusses other economic rationales for government intervention with respect to obesity, such as imperfect information, time inconsistent preferences, and irrational behavior. It concludes by proposing a research agenda for the field. Overall, the evidence suggests that there is no single dominant economic cause of obesity; a wide variety of factors may contribute a modest amount to the risk. There is consistent evidence regarding the economic consequences of obesity, which are lower wages and higher medical care costs that impose negative externalities through health insurance. Studies of economic approaches to preventing obesity, such as menu labeling, taxes on energy-dense foods, and financial rewards for weight loss find only modest effects on weight and thus a range of policies may be necessary to have a substantial effect on the prevalence of obesity.

Savings in Medical Expenditures Associated with Reductions in Body Mass Index Among US Adults with Obesity, by Diabetes Status

BACKGROUND

The prevalence of obesity has more than doubled in the USA in the past 30 years. Obesity is a significant risk factor for diabetes, cardiovascular disease, and other clinically significant co-morbidities. This paper estimates the medical care cost savings that can be achieved from a given amount of weight loss by people with different starting values of body mass index (BMI), for those with and without diabetes. This information is an important input into analyses of the cost effectiveness of obesity treatments and prevention programs.

METHODS

Two-part models of instrumental variables were estimated using data from the Medical Expenditure Panel Survey (MEPS) for 2000-2010. Models were estimated for all adults as well as separately for those with and without diabetes. We calculated the causal impact of changes in BMI on medical care expenditures, cost savings for specific changes in BMI (5, 10, 15, and 20 %) from starting BMI levels ranging from 30 to 45 kg/m(2), as well as the total excess medical care expenditures caused by obesity.

RESULTS

In the USA, adult obesity raised annual medical care costs by $US3,508 per obese individual, for a nationwide total of $US315.8 billion (year 2010 values). However, the relationship of medical care costs over BMI is J-shaped; costs rise exponentially in the range of class 2 and 3 obesity (BMI ≥35). The heavier the obese individual, the greater the reduction in medical care costs associated with a given percent reduction in BMI. Medical care expenditures are higher, and rise more with BMI, among individuals with diabetes than among those without diabetes.

CONCLUSIONS

The savings from a given percent reduction in BMI are greater the heavier the obese individual, and are greater for those with diabetes than for those without diabetes. The results provide health insurers, employers, government agencies, and health economists with accurate estimates of the change in medical care expenditures resulting from weight loss, which is important information for calculating the cost effectiveness of interventions to prevent and treat obesity.

The Affordable Care Act permits greater financial rewards for weight loss: a good idea in principle, but many practical concerns remain

The Patient Protection and Affordable Care Act of 2010 (ACA) increased the maximum rewards that group health insurance plans (including employers who self-insure) may offer in their wellness programs, with the goal of incentivizing healthy behaviors such as weight loss among the obese and smoking cessation. In this essay, I describe the history and intention of such programs, and make the following three points: (1) In principle, incentivizing healthy behavior can reduce external costs and help people with time-inconsistent preferences stick to their resolutions; (2) there are problems with the design of this portion of the ACA that will limit its effectiveness in achieving these goals; and (3) financial rewards for healthy behaviors have a mixed record to date, and thus many practical design features need to be resolved to improve the effectiveness of such programs.

Effects of FTO RS9939906 and MC4R RS17782313 on obesity, type 2 diabetes mellitus and blood pressure in patients with hypertension

Background

Genetic variants of the FTO gene rs9939609 A/T and the MC4R gene rs17782313 C/T have been associated with obesity. Individuals with mutations in MC4R gene have lower blood pressure (BP), independently of obesity. This study aimed to investigate the association of FTO rs9939609 and MC4R rs17782313 with anthropometric indexes, BP, and type 2 diabetes mellitus among hypertensive patients.

Methods

We genotyped 217 individuals (86 men and 131 women) with hypertension (systolic or diastolic BP ≥ 140/90 mmHg or using antihypertensive drugs). Diabetes mellitus was diagnosed according to the American Diabetes Association criteria. Waist and neck circumferences (cm), Body Adiposity Index (BAI,%), Lipid Accumulation Product Index (LAP, cm.mmol.l) and body mass index (BMI, kg/m²) were analyzed using analysis of covariance or modified Poisson’s regression.

Results

Rare allele frequencies were 0.40 for A for FTO rs9939609 and 0.18 for C for MC4R rs17782313. A positive association of FTO rs9939609 and MC4R rs17782313 with BMI was observed in the overall sample. Among men and women, neck circumference was associated with the FTO genotype and, for women, MC4R genotype. In contrast, in men we found a negative association of MC4R rs17782313 with diastolic BP (TT 90.1 ±12.2, TC/CC 83.2 ±12.1; P = 0.03) and borderline association for systolic BP after controlling for age and BMI.

Conclusions

Common genetic variants of FTO rs9939609 have positive associations with BMI and neck circumference and MC4R rs17782313 in women, but a negative association with diastolic and mean blood pressure in men with hypertension.

Obesity-associated oxidative stress: strategies finalized to improve redox state

Obesity represents a major risk factor for a plethora of severe diseases, including diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and cancer. It is often accompanied by an increased risk of mortality and, in the case of non-fatal health problems, the quality of life is impaired because of associated conditions, including sleep apnea, respiratory problems, osteoarthritis, and infertility. Recent evidence suggests that oxidative stress may be the mechanistic link between obesity and related complications. In obese patients, antioxidant defenses are lower than normal weight counterparts and their levels inversely correlate with central adiposity; obesity is also characterized by enhanced levels of reactive oxygen or nitrogen species. Inadequacy of antioxidant defenses probably relies on different factors: obese individuals may have a lower intake of antioxidant- and phytochemical-rich foods, such as fruits, vegetables, and legumes; otherwise, consumption of antioxidant nutrients is normal, but obese individuals may have an increased utilization of these molecules, likewise to that reported in diabetic patients and smokers. Also inadequate physical activity may account for a decreased antioxidant state. In this review, we describe current concepts in the meaning of obesity as a state of chronic oxidative stress and the potential interventions to improve redox balance.