Genetic aspects of body composition

Impact of the FTO Gene Variation on Appetite and Fat Oxidation in Young Adults

The FTO rs9939609 gene, which presents three polymorphisms (AA, AT, and TT), has been associated with the development of obesity through an increased fat accumulation; however, the associations of the gene with other physiological mechanisms, such as appetite or fat oxidation, are still unclear. Therefore, this study aims to evaluate the influence of the FTO rs9939609 gene on different obesity-related factors in young adults. The FTO rs9939609 polymorphism was genotyped in 73 participants (28 women, 22.27 ± 3.70 years). Obesity-related factors included dietary assessment, physical activity expenditure, body composition, appetite sensation, resting metabolic rate, maximal fat oxidation during exercise (MFO), and cardiorespiratory fitness. Our results showed that TT allele participants expressed higher values of hunger (p = 0.049) and appetite (p = 0.043) after exercising compared to the AT allele group. Moreover, the TT allele group showed significantly higher values of MFO (p = 0.031) compared to the AT group, regardless of sex and body mass index. Thus, our results suggest that the FTO rs9939609 gene has an influence on appetite, hunger, and fat oxidation during exercise, with TT allele participants showing significantly higher values compared to the AT allele group. These findings may have practical applications for weight loss and exercise programs.

Cervical body composition on radiotherapy planning computed tomography scans predicts overall survival in glioblastoma patients

Background and purpose

Glioblastoma (GBM) patients face a strongly unfavorable prognosis despite multimodal therapy regimens. However, individualized mortality prediction remains imprecise. Harnessing routine radiation planning cranial computed tomography (CT) scans, we assessed cervical body composition measures as novel biomarkers for overall survival (OS) in GBM patients.

Materials and methods

We performed threshold-based semi-automated quantification of muscle and subcutaneous fat cross-sectional area (CSA) at the levels of the first and second cervical vertebral body. First, we tested this method's validity by correlating cervical measures to established abdominal body composition in an open-source whole-body CT cohort. We then identified consecutive patients undergoing radiation planning for recent GBM diagnosis at our institution from 2010 to 2020 and quantified cervical body composition on radiation planning CT scans. Finally, we performed univariable and multivariable time-to-event analyses, adjusting for age, sex, body mass index, comorbidities, performance status, extent of surgical resection, extent of tumor at diagnosis, and MGMT methylation.

Results

Cervical body composition measurements were well-correlated with established abdominal markers (Spearman's rho greater than 0.68 in all cases). Subsequently, we included 324 GBM patients in our study cohort (median age 63 years, 60.8% male). 293 (90.4%) patients died during follow-up. Median survival time was 13 months. Patients with below-average muscle CSA or above-average fat CSA demonstrated shorter survival. In multivariable analyses, continuous cervical muscle measurements remained independently associated with OS.

Conclusion

This exploratory study establishes novel cervical body composition measures routinely available on cranial radiation planning CT scans and confirms their association with OS in patients diagnosed with GBM.

Hepatic glycogenolysis is determined by maternal high-calorie diet via methylation of Pygl and it is modified by oteocalcin administration in mice

Objective

Accumulating evidence indicates that an adverse perinatal environment contributes to a higher risk of metabolic disorders in the later life of the offspring. However, the underlying molecular mechanisms remain largely unknown. Thus, we investigated the contribution of maternal high-calorie diet and osteocalcin to metabolic homeostasis in the offspring.

Methods

Eight-week-old C57Bl/6N female mice were mated with age-matched males and allocated randomly to three groups: a normal-diet (ND) or a high-fat, high-sucrose diet group, which was administered either saline (control) or GluOC (10 ng/g body mass) from the day of mating to that of delivery, and the dams were fed a ND after the delivery. Pups weaned at 24 days after birth were analyzed.

Results

A maternal high-fat, high-sucrose diet during pregnancy causes metabolic disorders in the liver of the offspring via hypermethylation of the Pygl gene, encoding glycogen phosphorylase L, which mediates hepatic glycogenolysis. The reduced expression of Pygl induced by the maternal diet causes the hepatic accumulation of glycogen and triglyceride in the offspring, which remains in adulthood. In addition, the administration of uncarboxylated osteocalcin during pregnancy upregulates Pygl expression via both direct CREBH and ATF4 and indirect epigenomic pathways, mitigating the maternal diet-induced obesity and abnormal glucose and lipid metabolism in adulthood.

Conclusions

We propose that maternal energy status is reflected in the hepatic glycogenolysis capacity of the offspring via epigenetic modification of Pygl and uncarboxylated osteocalcin regulates glycogenolysis.

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A high-calorie diet during pregnancy causes metabolic disorders in mouse offspring.

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These are mediated by low liver expression of Pygl encoding glycogen phosphorylase.

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Hypermethylation of the Pygl promoter in utero suppresses subsequent gene expression.

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Modification and phenotypic changes are prevented by GluOC administration during pregnancy.

Interaction between Metabolic Genetic Risk Score and Dietary Fatty Acid Intake on Central Obesity in a Ghanaian Population

Obesity is a multifactorial condition arising from the interaction between genetic and lifestyle factors. We aimed to assess the impact of lifestyle and genetic factors on obesity-related traits in 302 healthy Ghanaian adults. Dietary intake and physical activity were assessed using a 3 day repeated 24 h dietary recall and global physical activity questionnaire, respectively. Twelve single nucleotide polymorphisms (SNPs) were used to construct 4-SNP, 8-SNP and 12-SNP genetic risk scores (GRSs). The 4-SNP GRS showed significant interactions with dietary fat intakes on waist circumference (WC) (Total fat, P_interaction = 0.01; saturated fatty acids (SFA), P_interaction = 0.02; polyunsaturated fatty acids (PUFA), P_interaction = 0.01 and monounsaturated fatty acids (MUFA), P_interaction = 0.01). Among individuals with higher intakes of total fat (>47 g/d), SFA (>14 g/d), PUFA (>16 g/d) and MUFA (>16 g/d), individuals with ≥3 risk alleles had a significantly higher WC compared to those with <3 risk alleles. This is the first study of its kind in this population, suggesting that a higher consumption of dietary fatty acid may have the potential to increase the genetic susceptibility of becoming centrally obese. These results support the general dietary recommendations to decrease the intakes of total fat and SFA, to reduce the risk of obesity, particularly in individuals with a higher genetic predisposition to central obesity.

Genetic Basis of Obesity and Type 2 Diabetes in Africans: Impact on Precision Medicine

PURPOSE OF REVIEW

Recent advances in genomics provide opportunities for novel understanding of the biology of human traits with the goal of improving human health. Here, we review recent obesity and type 2 diabetes (T2D)-related genomic studies in African populations and discuss the implications of limited genomics studies on health disparity and precision medicine.

RECENT FINDINGS

Genome-wide association studies in Africans have yielded genetic discovery that would otherwise not be possible; these include identification of novel loci associated with obesity (SEMA-4D, PRKCA, WARS2), metabolic syndrome (CA-10, CTNNA3), and T2D (AGMO, ZRANB3). ZRANB3 was recently demonstrated to influence beta cell mass and insulin response. Despite these promising results, genomic studies in African populations are still limited and thus genomics tools and approaches such as polygenic risk scores and precision medicine are likely to have limited utility in Africans with the unacceptable possibility of exacerbating prevailing health disparities. African populations provide unique opportunities for increasing our understanding of the genetic basis of cardiometabolic disorders. We highlight the need for more coordinated and sustained efforts to increase the representation of Africans in genomic studies both as participants and scientists.

Influence of FTO rs9939609 and Mediterranean diet on body composition and weight loss: a randomized clinical trial

Background

The Mediterranean diet (MeD) plays a key role in the prevention of obesity. Among the genes involved in obesity, the Fat mass and obesity-associated gene (FTO) is one of the most known, but its interaction with MeD remained uncertain so far.

Methods

We carried out a study on a sample of 188 Italian subjects, analyzing their FTO rs9939609 alleles, and the difference in body composition between the baseline and a 4-weeks nutritional intervention. The sample was divided into two groups: the control group of 49 subjects, and the MeD group of 139 subjects.

Results

We found significant relations between MeD and both variation of total body fat (ΔTBFat) (p = 0.00) and gynoid body fat (p = 0.04). ∆TBFat (kg) demonstrated to have a significant relation with the interaction diet-gene (p = 0.04), whereas FTO was associated with the variation of total body water (p = 0.02).

Conclusions

MeD demonstrated to be a good nutritional treatment to reduce the body fat mass, whereas data about FTO remain uncertain. Confirming or rejecting the hypothesis of FTO and its influence on body tissues during nutritional treatments is fundamental to decide whether its effect has to be taken into consideration during both development of dietetic plans and patients monitoring.

Trial Registration ClinicalTrials.gov Id: NCT01890070. Registered 01 July 2013, https://clinicaltrials.gov/ct2/show/NCT01890070

[Dietary interventions and social care for treating obesity in children]

The prevalence of obesity and associated comorbidities among children and adolescents has risen worldwide throughout the past 3 decades. To break this trend, population-based activities in health promotion/prevention and health care are necessary. Studies showed that long-term eating behavior improvement with the cooperation of the patient's family together with child-friendly organization support both individual therapeutic improvements as well as a relevant reduction of obesity prevalence. A significant BMI reduction can be achieved with a normal varied diet, whose energetic value is 300-400 kcal/day below the patient's daily energetic needs, due to the lower consumption of fat and sugar. This requires, however, that the entire family be willing to change their unhealthy eating behaviors (e.g., soft drinks and fast food) and to introduce regular meals into their daily routine. Sensibly, most therapies combine diet therapy with increased physical activity and parental training. Controlled media consumption, active leisure-time behavior, and a structured daily routine are further conditions for successful weight reduction. The high-risk groups for pediatric obesity, i.e., families with migration background and/or low socioeconomic status, have been poorly reached by established programs.

Energy expenditure adjusted for body composition differentiates constitutional thinness from both normal subjects and anorexia nervosa

Constitutional thinness (CT) is characterized by a low and stable body mass index (BMI) without any hormonal abnormality. To understand the weight steadiness, energetic metabolism was evaluated. Seven CT, seven controls, and six anorexia nervosa (AN) young women were compared. CT and AN had a BMI <16.5 kg/m(2). Four criteria were evaluated: 1) energy balance including diet record, resting metabolic rate (RMR) (indirect calorimetry), total energy expenditure (TEE) (doubly labeled water), physical activity; 2) body composition (dual-energy X-ray absorptiometry); 3) biological markers (leptin, IGF-I, free T3); 4) psychological profile of eating behavior. The normality of free T3 (3.7 +/- 0.5 pmol/l), IGF-I (225 +/- 93 ng/ml), and leptin (8.3 +/- 3.4 ng/ml) confirmed the absence of undernutrition in CT. Their psychological profiles revealed a weight gain desire. TEE (kJ/day) in CT (8,382 +/- 988) was not found significantly different from that of controls (8,793 +/- 845) and AN (8,001 +/- 2,152). CT food intake (7,565 +/- 908 kJ/day) was found similar to that of controls (7,961 +/- 1,452 kJ/day) and higher than in AN (4,894 +/- 703 kJ/day), thus explaining the energy metabolism balance. Fat-free mass (FFM) (kg) was similar in CT and AN (32.5 +/- 2.9 vs. 34.1 +/- 1.9) and higher in controls (37.8 +/- 1.6). While RMR absolute values (kJ/day) were lower in CT (4,839 +/- 473) than in controls (5,576 +/- 209), RMR values adjusted for FFM were the highest in CT. TEE-to-FFM ratio was also higher in CT than in controls. Energetic metabolism balance maintains a stable low weight in CT. An increased energy expenditure-to-FFM ratio differentiates CT from controls and could account for the resistance to weight gain observed in CT.

Nutrient intake, weight, and Leu7Pro polymorphism in prepro-neuropeptide Y in children

CONTEXT

The important role of neuropeptide Y (NPY) in the regulation of food intake and energy balance has been firmly documented in rodents, but human data are sparse. The recently identified functional Leu7Pro polymorphism in the signal peptide region of the prepro-NPY is a useful tool for the investigation of the role of NPY in men. Pro7 substitution has been associated with the following: plasma NPY concentration, the risk factors of cardiovascular disease, birth weight of children, serum triglyceride concentration, and the function of vascular endothelium.

OBJECTIVE

The objective of this study was to analyze the connection between Leu7Pro polymorphism and relative weight, nutrient intakes, and serum lipids in early childhood. We closely followed 647 healthy Finnish children participating in the Special Turku Risk Factor Intervention Project through their first 9 yr of life.

RESULTS

Leu7Pro polymorphism showed no relation to intakes of energy, macronutrients, or the relative weight in either gender. However, Pro7 substitution was associated with serum triglyceride concentration in boys at the ages of 5, 7, and 9 yr.

CONCLUSION

The functional Leu7Pro polymorphism is not likely to be involved in the regulation of adiposity or major nutrient preferences in childhood. In boys, the Pro7 variant may have impact on serum triglyceride concentration.

Somatotropic and gonadotropic axes linkages in infancy, childhood, and the puberty-adult transition

Integrative neuroendocrine control of the gonadotropic and somatotropic axes in childhood, puberty, and young adulthood proceeds via multiple convergent and divergent pathways in the human and experimental animal. Emerging ensemble concepts are required to embody independent, parallel, and interacting mechanisms that subserve physiological adaptations and pathological disruption of reproduction and growth. Significant advances in systems biology will be needed to address these challenges.

Genes, lifestyles and obesity

OBJECTIVE

To review the role of genes and lifestyle factors, particularly dietary habits and physical activity patterns, in obesity risk as well as their potential interactions.

DESIGN AND MEASUREMENTS

A descriptive report of a number of genes definitely ascribed or potentially implicated in excessive fat accumulation leading to obesity as assessed by different research approaches (Mendelian transmission, genetic animal models, epidemiological association/linkage studies and genome-wide scans). Also, the involvement of macronutrient intake and composition (fat/carbohydrate) as well as the role of activity-linked energy expenditure in obesity onset is reviewed.

RESULTS

Examples of the role of the genotype as well as of the dietary macronutrient composition/intake and sedentary/low energy cost of physical activities in obesity prevalence are reported.

CONCLUSIONS

Both genes and everyday life environmental factors such as cultural and social mediated food intake and reduced domestic and living work activities are involved in the obesity pandemia. The occurrence of gene x gene and gene x environmental factors interactions makes it more difficult to interpret the specific roles of genetics and lifestyle in obesity risk.

Endocrine control of body composition in infancy, childhood, and puberty

Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.

Osteogenic Differentiation of Recombinant Adeno-Associated Virus 2-Transduced Murine Mesenchymal Stem Cells and Development of an Immunocompetent Mouse Model forEx VivoOsteoporosis Gene Therapy

Gene therapy for osteopenic conditions including osteoporosis is a potential alternative to pharmacotherapy for cost effectiveness, long-term viability, and the ability to enhance bone mass by anabolic approaches. Increased understanding of mesenchymal stem cell (MSC) lineage differentiation during osteogenesis, and of the molecular pathways involved in bone cell production, provides an opportunity for the advancement of gene therapy approaches for osteopenic conditions. The potential of MSCs in osteoblast differentiation and the relative ease of MSC isolation and culturing offer a promising resource for the development of ex vivo gene therapy for bone defects. In an effort to develop ex vivo gene therapy for osteoporosis, we used gene-modified MSCs in a preclinical mouse model to determine the efficiency of transduction of murine MSCs by recombinant adeno-associated virus 2 (AAV) vectors carrying reporter genes and determined their osteogenic potential after recombinant AAV-mediated expression of bone morphogenic protein 2, known to induce osteoblast differentiation. Although surgical ovariectomy is believed to induce progressive bone loss in mouse models, similar to an osteoporosis-like phenotype in humans, several factors, including hormonal alteration and dietary habits, significantly affect both the onset and progression of the disease. Thus, in the present study, we determined the influence of these factors and developed an immunocompetent mouse model of osteoporosis with degenerative bone loss as in the human pathology.

Long-term divergent selection on fatness in mice indicates a regulation system independent of leptin production and reception

Divergent selection in mice on fatness over 60 generations produced a fat (F) and a lean (L) line, having about 22% and 4% body fat, respectively. To elucidate the importance of the leptin regulatory feedback loop in the genetic changes produced by this selection, Lep(ob) and Lepr(db) mutations causing leptin production and leptin receptor deficiency, respectively, were introgressed individually into both lines by repeated backcrossing. The fat amount increased significantly in homozygotes for Lep(ob) or Lepr(db) in both lines, for example, in F and L males from 8.5 to 18.8 and 17.2 g (P<0.001) and from 1.25 to 18.0 and 12.7 g (P<0.001), respectively. Line differences were, however, mostly maintained after introgression. Concentrations of circulating leptin were relatively independent of the original lines but heavily dependent on the introgressed genotype. Introgression of leptin production and receptor deficiencies had separate effects from long-term selection, indicating that the genes responsible for the line divergence must act independently of the leptin regulatory system. Energy budget analysis indicated that the major line differences were in the level of energy expended on physical activity, and these differences were preserved following introgression, suggesting that multiple pathways regulate fatness, which may be independently responsive to intervention.