Polymorphisms in Genes Involved in the Leptin-Melanocortin Pathway are Associated with Obesity-Related Cardiometabolic Alterations in a Southern Chilean Population

Influence of polymorphisms in IRS1, IRS2, MC3R, and MC4R on metabolic and inflammatory status and food intake in Brazilian adults: An exploratory pilot study

Polymorphisms in genes of leptin-melanocortin and insulin pathways have been associated with obesity and type 2 diabetes. We hypothesized that polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory markers and food intake composition in Brazilian subjects. This exploratory pilot study included 358 adult subjects. Clinical, anthropometric, and laboratory data were obtained through interview and access to medical records. The variants IRS1 rs2943634 A˃C, IRS2 rs1865434 C>T, MC3R rs3746619 C>A, and MC4R rs17782313 T>C were analyzed by real-time polymerase chain reaction. Food intake composition was assessed in a group of subjects with obesity (n = 84) before and after a short-term nutritional counseling program (9 weeks). MC4R rs17782313 was associated with increased risk of obesity (P = .034). Multivariate linear regression analysis adjusted by covariates indicated associations of IRS2 rs1865434 with reduced low-density lipoprotein cholesterol and resistin, MC3R rs3746619 with high glycated hemoglobin, and IRS1 rs2943634 and MC4R rs17782313 with increased high-sensitivity C-reactive protein (P < .05). Energy intake and carbohydrate and total fat intakes were reduced after the diet-oriented program (P < .05). Multivariate linear regression analysis showed associations of IRS2 rs1865434 with high basal fiber intake, IRS1 rs2943634 with low postprogram carbohydrate intake, and MC4R rs17782313 with low postprogram total fat and saturated fatty acid intakes (P < .05). Although significant associations did not survive correction for multiple comparisons using the Benjamini-Hochberg method in this exploratory study, polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory status in Brazilian adults. IRS1 and MC4R variants may influence carbohydrate, total fat, and saturated fatty acid intakes in response to a diet-oriented program in subjects with obesity.

Implication of Melanocortin Receptor Genes in the Familial Comorbidity of Type 2 Diabetes and Depression

The melanocortin receptors are G-protein-coupled receptors, which are essential components of the hypothalamic–pituitary–adrenal axis, and they mediate the actions of melanocortins (melanocyte-stimulating hormones: α-MSH, β-MSH, and γ-MSH) as well as the adrenocorticotropin hormone (ACTH) in skin pigmentation, adrenal steroidogenesis, and stress response. Three melanocortin receptor genes (MC1R, MC2R, and MC5R) contribute to the risk of major depressive disorder (MDD), and one melanocortin receptor gene (MC4R) contributes to the risk of type 2 diabetes (T2D). MDD increases T2D risk in drug-naïve patients; thus, MDD and T2D commonly coexist. The five melanocortin receptor genes might confer risk for both disorders. However, they have never been investigated jointly to evaluate their potential contributing roles in the MDD-T2D comorbidity, specifically within families. In 212 Italian families with T2D and MDD, we tested 11 single nucleotide polymorphisms (SNPs) in the MC1R gene, 9 SNPs in MC2R, 3 SNPs in MC3R, 4 SNPs in MC4R, and 2 SNPs in MC5R. The testing used 2-point parametric linkage and linkage disequilibrium (LD) (i.e., association) analysis with four models (dominant with complete penetrance (D1), dominant with incomplete penetrance (D2), recessive with complete penetrance (R1), and recessive with incomplete penetrance (R2)). We detected significant (p ≤ 0.05) linkage and/or LD (i.e., association) to/with MDD for one SNP in MC2R (rs111734014) and one SNP in MC5R (rs2236700), and to/with T2D for three SNPs in MC1R (rs1805007 and rs201192930, and rs2228479), one SNP in MC2R (rs104894660), two SNPs in MC3R (rs3746619 and rs3827103), and one SNP in MC4R genes (Chr18-60372302). The linkage/LD/association was significant across different linkage patterns and different modes of inheritance. All reported variants are novel in MDD and T2D. This is the first study to report risk variants in MC1R, MC2R, and MC3R genes in T2D. MC2R and MC5R genes are replicated in MDD, with one novel variant each. Within our dataset, only the MC2R gene appears to confer risk for both MDD and T2D, albeit with different risk variants. To further clarity the role of the melanocortin receptor genes in MDD-T2D, these findings should be sought among other ethnicities as well.

The Interaction Between Dietary Total Antioxidant Capacity and MC4R Gene and HOMA-IR in Metabolically Healthy and Unhealthy Overweight and Obese Women

Introduction

The current prevalence of the metabolically healthy obesity is about 3%. Genetic and nutrition are influencers of such phenotypes. The main goal of this study was to assess the interaction between Dietary Total Antioxidant Capacity (DTAC) and the genotypes of MC4R and Insulin resistance in metabolically healthy/unhealthy overweight and obese women in Iran.

Material And Methods

This cross-sectional study was conducted on 237 overweight-obese women with a mean age of 36. The value of Dietary total antioxidant capacity (DTAC) was calculated using the following indices: Total reactive antioxidant potential (TRAP), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing ability of plasma (FRAP). The Metabolic health status was evaluated using the Karelis criteria. Melanocortin 4 receptor single nucleotide polymorphisms were determined by the restriction fragment length polymorphism (PCR-RFLP) method. Also, insulin resistance was evaluated through homeostasis model assessment (HOMA).

Result

Our data noted that 72.96% of participants presented Unhealthy Metabolically and 26.94% Healthy Metabolically including 33.5% of the total had T/T genotype, 23.8% had the C/T genotype, and 42.5% had the C/C genotype (P = .05). A linear regression model test showed that the probability of metabolically healthy obesity was significantly higher in patients with the T/C genotype. The test value was statistically significant (95% CI: 0.000-0.001; P = .056, β = 0). No statistically significant relation was observed between study parameters and DTAC values. HOMA-Index was higher in all unhealthy subjects significantly.

Conclusions

The findings indicated that there are significant associations between genotypes of rs1333048 SNP and DTAC. The C/C genotype subjects with higher DTAC had a better lipid profile and were metabolically healthier.

The interaction between Alternative Healthy Eating Index and MC4R rs17782313 gene variants on central and general obesity indices in women: a cross-sectional study

BACKGROUND

Previous studies have shown that the C allele of melanocortin 4 receptor (MC4R) rs17782313 and Alternative Healthy Eating Index (AHEI) are separately associated with obesity. However, no study has assessed the aim of this study which is to investigate the interaction between MC4R rs17782313 variants and AHEI and their association with central and general obesity indices.

METHODS

A total of 291 women with BMI ≥25 and aged 18-48 years enrolled in this cross-sectional study. All participants were assessed for body composition, anthropometric measures, dietary intake, and blood parameters. After obtaining data of dietary intake from the 147-item food frequency questionnaire (FFQ) the AHEI was calculated. MC4R rs17782313 SNPs were assessed using the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

After adjustment for age, energy intake, physical activity, marital and economic status, the interaction between MC4R rs17782313 and AHEI was associated with hip circumference (HC) (β=-0.41, 95%CI: -0.77 to -0.05, P=0.02), body mass index (BMI) (β=-0.15, 95%CI: -0.29 to -0.02, P=0.02), fat mass (kg) (β=-0.28, 95%CI: -0.56 to -0.01, P=0.03), Visceral fat area (VFA) (β=-5.68, 95%CI: -9.55 to -1.80, P=0.004). The other measures that seem to be suggestively related to this interaction (0.05< P <0.07) are waist circumference (WC), waist-to-height ratio (WHtR), trunk fat (TF) (%), TF (kg), fat mass (%), and fat mass index (FMI).

CONCLUSION

Interaction between MC4R rs17782313 and AHEI can be related to some central and general obesity indices in overweight/obese women. This article is protected by copyright. All rights reserved.

Gene Polymorphisms of Hormonal Regulators of Metabolism in Patients with Schizophrenia with Metabolic Syndrome

Background: Metabolic syndrome (MetS) is a common complication of long-term treatment of persons with schizophrenia taking (atypical) antipsychotics. In this study, we investigated the existence of an association with polymorphisms of genes for four hormones that regulate energy metabolism. Methods: We recruited 517 clinically admitted white patients (269M/248F) with a verified diagnosis of schizophrenia (ICD-10) and with a stable physical condition. Participants were classified for having or not having MetS and genotyped for 20 single-nucleotide polymorphisms (SNPs) in the genes encoding insulin-induced gene 2 (INSIG2), ghrelin (GHRL), leptin (LEP), and leptin receptor (LEPR). Results: The 139 patients (26.9%) with MetS were significantly more likely to be women, older, and ill longer, and had a larger body mass index (BMI). Four polymorphisms (rs10490624, rs17587100, rs9308762, and rs10490816) did not meet the Hardy–Weinberg equilibrium (HWE) criterion and were excluded. Only genotypes and alleles of the rs3828942 of LEP gene (chi2 = 7.665, p = 0.022; chi2 = 5.136, p = 0.023) and the genotypes of the rs17047718 of INSIG2 gene (chi2 = 7.7, p = 0.021) had a significant association with MetS. Conclusions: The results of our study suggest that the LEP and INSIG2 genes play a certain causal role in the development of MetS in patients with schizophrenia.

Effects of genetic polymorphisms in body mass index according to dietary exposure to bisphenols and parabens

A growing body of evidence supports that more than 900 single nucleotide polymorphisms (SNPs) and exposure to endocrine disrupting chemicals, such as bisphenols and parabens, are important contributors to the development of obesity. The aim of this study was to evaluate the way in which fat mass and obesity-associated gene (FTO) rs9939609 and leptin receptor (LEPR) rs9436303 variants contribute to variability in body mass index (BMI) according to estimated dietary exposure of bisphenols and parabens. This cross-sectional study included 101 Spanish participants (16-24 years). SNP genotyping assays were performed through quantitative PCRs (qPCRs) using Taqman® probes. Dietary exposure to bisphenols and parabens was calculated from food frequency questionnaire and chemical determination in food samples by ultra-high performance liquid chromatography-tandem mass spectrometry system. Linear regression models were conducted to address the association of genetic variants and BMI according to levels of bisphenols/parabens exposure. Risk G allele of LEPR rs9436303 was significantly positively associated with BMI (exp (β) = 1.20, 95% CI: 1.04-1.38, p = 0.011). In participants highly exposed to bisphenols, the LEPR rs9436303 G allele was related to a significant increased BMI (exp (β) = 1.27, 95% CI: 1.03-1.57, p = 0.024). A more relevant trend was observed with high exposure to parabens (exp (β) = 1.33, 95% CI: 1.08-1.63, p = 0.009). We provide the first evidence that interaction between LEPR polymorphism and dietary intake of bisphenols and parabens may be responsible for an increased BMI, suggesting a potential effect in obesity. Moreover, we proposed LEPR rs9436303 as a genetic marker of susceptibility to excess weight induced by exposure.

The impact of CPT1B rs470117, LEPR rs1137101 and BDNF rs6265 polymorphisms on the risk of developing obesity in an Italian population

OBJECTIVE

This study aimed to analyze 11 single nucleotide polymorphisms (SNPs) belonging to 9 genes involved in metabolic pathways (BDNF rs6265; PNPLA3 rs2294918 and rs2076212; CIDEA rs11545881; NTRK2 rs2289658; ALOX12 rs1126667; ALOX12B rs2304908; LEPR rs1137101; CPT1B rs470117 and rs8142477; rs2305507 CPT1A) in obese patients and controls.

METHODS

Polymorphisms were analyzed in 300 severe obese patients undergoing bariatric surgery (body mass index >30 kg/m²) and 404 control subjects in order to evaluate their association with obesity and clinical variables.

RESULTS

Our findings showed significant differences for the allelic distributions of CPT1B rs470117 and LEPR rs11371010 in obese subjects compared to controls. The BDNF rs6265 correlates with obesity only when associated with the other two SNPs. In particular, for CPT1B rs470117 and LEPR rs1137101, the rare allele was associated with a reduced risk of developing the obese phenotype, whereas the simultaneous presence of the common C allele for rs470117 and A allele for rs1137101 was more frequent in obese patients (p = 0.002, OR = 1.417). A significant association between CPT1B rs470117 and steatosis was found. Moreover, we observed that by associating the rare allele T of the BDNF rs6265 with the most common alleles of the SNPs CPT1B rs470117 and LEPR rs1137101, the combination of T-C-A alleles was associated with a higher risk of developing an obese phenotype (p = 0.001, OR = 1.6679).

CONCLUSIONS

Our results suggest that SNPs CPT1B rs470117 and LEPR rs1137101 taken individually and in association with BDNF rs6265 may be involved in an increased risk of developing obese phenotype in an Italian cohort.

Peripheral Blood miRome Identified miR-155 as Potential Biomarker of MetS and Cardiometabolic Risk in Obese Patients

This study explored circulating miRNAs and target genes associated with metabolic syndrome (MetS) and cardiometabolic risk in obese patients. Small-RNA sequencing was used to assess the peripheral blood miRNome of 12 obese subjects (6 MetS and 6 non-MetS). Differentially expressed miRNAs and target genes were further analyzed by qPCR in a larger sample of obese patients (48 MetS and 32 non-MetS). miRNA:mRNA interactions were studied using in silico tools. miRNome analysis identified 10 downregulated miRNAs in MetS compared to non-Met patients (p < 0.05). In silico studies revealed three miRNAs (miR-155, miR-181a, and let-7a) and their predictive targets (CCAAT/enhancer-binding protein beta-CEBPB, KRAS proto-oncogene, GTPase-KRAS and suppressor of cytokine signaling 1-SOCS1) with a potential role in the insulin receptor signaling pathway. miR-155 expression was reduced and CEBPB mRNA levels were increased in MetS patients (p < 0.05), and these effects were correlated with the number of MetS diagnostic criteria (p < 0.05). Increased HOMA-IR (>7.6) was associated with low miR-155 levels, high CEBPB expression, and serum hsCRP (p < 0.05). miR-155 was negatively correlated with CEBPB, HOMA-IR, and plasma fibrinogen, and positively correlated with serum adiponectin (p < 0.05). Downregulation of circulating miR-155 is associated with insulin resistance, poor glycemic control, and increased MetS-related cardiometabolic risk, and these effects are potentially mediated by interaction with CEBPB.

Fat mass and obesity-associated (FTO) and leptin receptor (LEPR) gene polymorphisms in Egyptian obese subjects

BACKGROUND

Several studies addressed the contribution of fat mass and obesity-associated (FTO) and leptin receptor (LEPR) polymorphisms for the susceptibility to obesity among different ethnic subjects. The main purpose of this work is to evaluate the association of these polymorph\isms with obesity among Egyptian subjects.

SUBJECTS AND METHODS

This case-control study was carried out on 110 unrelated obese Egyptian subjects who were compared with 122 controls. Their genomic DNA was genotyped using the PCR technique.

RESULTS

The allelic frequencies of FTO rs9939609 (A) and LEPR rs1137101 (223R) were significantly higher in obese subjects compared with non-obese controls (p < .001). Comparing different phenotype frequencies including clinical, anthropometric, and biochemical parameters in obese subjects revealed no significant difference in relation to their genotype frequencies (p> .05).

CONCLUSIONS

This study designates a strong association for FTO and LEPR variants with the risk of obesity among Egyptian subjects.

Polymorphisms of leptin-melanocortin system genes associated with obesity in an adult population from Barranquilla

Introduction: Obesity is considered a serious public health problem. Efforts have been directed to search for candidate genes such as LEP, LEPR, and MC4R involved in the leptin-melanocortin system. The neuroendocrine regulation of these genes on energy intake and balance influences the pathogenesis of this disease. Contradictory results regarding the association of these genes with obesity raise the need for new research. Objective: To analyze the association between obesity and LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms and the clinical and biochemical variables in obese adults from Barranquilla, Colombia. Materials and methods: We analyzed 111 obese adults and 155 non-obese individuals as controls. The polymorphisms were determined by real-time PCR. Besides, anthropometric measures, blood pressure, and biochemical tests were evaluated. Results: No statistical differences were found in allele and genotype frequencies of gene polymorphisms between groups. The CC genotype of MC4R rs17782313 polymorphism was associated with increased systolic blood pressure and T allele and TT genotype, with decreased HDL cholesterol in obese adults. The effect of the other polymorphisms on these variables was not evidenced. Conclusions: LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms were not associated with obesity in the population under study. MC4R rs17782313 polymorphisms were associated with an increase in systolic blood pressure and a decrease in HDL cholesterol.

The Relationship Between Selected CNR1, MC4R, LEP, FTO and VDR Gene Polymorphisms and Several Basic Toxicological Parameters Among Persons Occupationally Exposed to Arsenic, Cadmium and Lead

The purpose of this work was to assess the influence of selected CNR1, MC4R, LEP, FTO and VDR FOKI gene polymorphisms on blood and urine concentration markers of lead, cadmium and arsenic in a population directly exposed to these metals. Eighty-five people exposed to lead, arsenic and cadmium were qualified to take part in the study. Standard urine samples and 25mL of venous blood from each worker were collected to assay basic laboratory and toxicological markers as well as selected single nucleotide polymorphisms (SNPs) within CNR1-cannabinoid receptor 1 gene (rs806368, rs806381, rs1049353, rs12720071), MC4R-melanocortin 4 receptor gene (rs17782313), LEP-leptin promoter gene (rs7799039), FTO-alpha-ketoglutarate-dependent dioxygenase gene (rs9939609) and VDR-vitamin D receptor (rs10735810) genes. It appeared that, except for the MC4R SNP, all the other polymorphisms were found to be associated with various laboratory parameters. Arsenic concentration in urine was associated with all four CNR1 and LEP SNPs, while cadmium concentration in blood was affected by the VDR polymorphism. Moreover, some significant relationships were also observed between CNR1 rs1049353 and FTO rs9939609 gene variants and markers of lead exposure. These results imply SNPs within genes coding for proteins involved in development of metabolic syndrome may be of prognostic value for persons directly exposed to lead, cadmium and arsenic.

Prediction and Structural Comparison of Deleterious Coding Nonsynonymous Single Nucleotide Polymorphisms (nsSNPs) in Human LEP Gene Associated with Obesity

Leptin is a peptide hormone that regulates fat stores in the body and appetite by controlling the feeling of satiety. This hormone is secreted by the white adipose tissue and plays a role in the storage and mobilization of fatty acids. Mutations of the LEP gene have been associated with obesity in different populations; it is a multifactorial disease that constitutes a major public health problem. In this study, we evaluated the impact of missense SNPs in the LEP gene extracted from dbSNP using 8 computational prediction tools. Out of the total of 4337 SNPs, 93 were nsSNPs (nonsynonymous single nucleotide polymorphisms). Among 93 nsSNPs, 12 (S46L, G59S, D61N, D100N, N103K, C117S, D76V, S88C, P90R, I95N, L161R, and R105W) variants were predicted to be the most deleterious by prediction software. On these 12 deleterious SNPs, 8 variants (S46L, G59S, D61N, D100N, N103K, C117S, L161R, and R105W) were located in the conserved positions and showed a decrease in structure stability which was evaluated by I-Mutant and Mupro. Then, by analyzing the different interactions between different amino acids in wild and mutated proteins, we assessed the structural impact of the deleterious modifications using the YASARA software. Among 8 deleterious nsSNPs, we revealed structure changes in the 6 variants S46L, G59S, D100N, L103K, R105W, L161R, two of which R105W, N103K were previously reported as associated with obesity. Our study suggests 6 deleterious mutations could play an important role in contributing to human obesity and worth to be included in association and functional studies, then may be a drug target.

Melanocortin 3 receptor gene polymorphism is associated with polycystic ovary syndrome in Turkish population

Polycystic ovary syndrome (PCOS) is a frequent complex disorder with an ill-defined etiology. Genetic factors seem rather effective at the occurrence of the disease, however, the evidence of established various studies results are unsatisfied. We aimed to make a contribution to the genetic baseline of the disease by investigating melanocortin 3 receptor gene polymorphism in affected patients. 101 PCOS patients and 162 age-matched healthy volunteered control subjects recruited to the study. PCOS patients classified according to their BMI class and insulin resistance situation. Anthropometric measurements, physical examination results, laboratory findings, and hormone levels were recorded for each participant and analysis of two SNPs on the MC3R gene; rs3746619 and rs3827103 were performed. Although no significant difference was observed in rs3827103 polymorphism between PCOS patients and controls; rs3746619 polymorphism was determined associated with PCOS in the heritage of dominant (AA + AC) and co-dominant (AA) genotypes. Two polymorphisms did not found related to obesity and insulin resistance in PCOS subgroups analysis. MC3R gene rs 3746619 polymorphism was found associated with PCOS in the Turkish population and may make a contribution to the genetic baseline of the disease.

Genetic aspects of metabolic disorders in pregnant women with pathological weight gain

Polymorphism of the leptin receptor gene (LEPR) has been shown to be linked to obesity-related metabolic markers and phenotype. Therefore, we hypothesized that the Gln233Arg LEPR polymorphism is related to metabolic changes in pregnancy and the risk of excessive gestational weight gain (GWG). A total of 97 pregnant women with a singleton gestation were enrolled from April 2016 until December 2018. Genetic variants of LEPR were analyzed by real-time polymerase chain reaction, leptin by enzyme-linked immunosorbent assay, lipid profile, and carbohydrate status were assessed in the first, and third trimesters of pregnancy. The recommended GWG was diagnosed in 34.0%, insufficient in 19.6%, and excessive in 46.4% patients. Statistical analysis revealed that 20.6% patients were with AA genotype, 50.5% – AG genotype, and 28.9% – GG genotype. The frequency of GG-alleles carriers of the LEPR Gln233Arg gene in the group of excessive GWG patients was 3 times higher compared to recommended GWG patients. Thus, the inheritance of pathological G-homozygotes increases the risk of excessive weight gain by 7 times, compared to carriers of the AA genotype. LEPR GG polymorphism was significantly associated with high levels of triglycerides, total cholesterol, lipoprotein low and very low density, and leptin compared to homozygous А-carriers in the third trimester of pregnancy. In pregnant women with GG polymorphism, the glucose level, insulin level, and HOMO-IR index were significantly increased compared to women with AA genotype in late pregnancy. In the group with excessive GWG, the presence of GG-alleles of the LEPR gene was accompanied by a higher level of hyperleptinemia, compared to carriers of AA-genotype. Inheritance of pathological G-homozygotes was associated with hyperlipidemia, leptin resistance with high leptin serum levels, and increased insulin resistance, which was especially manifested in excessive GWG. In our opinion, excessive GWG can be seen as a marker of the mother's genotype and genetic predisposition to the development of metabolic diseases after delivery.

Common Polymorphisms Linked to Obesity and Cardiovascular Disease in Europeans and Asians are Associated with Type 2 Diabetes in Mexican Mestizos

Background and objectives: Type 2 diabetes (T2D) is a major problem of public health in Mexico. We investigated the influence of five polymorphisms, previously associated with obesity and cardiovascular disease in Europeans and Asians, on T2D in Mexican Mestizos. Materials and Methods: A total of 1358 subjects from 30 to 85 years old were genotyped for five loci: CXCL12 rs501120; CDNK2A/B rs1333049; HNF-1α rs2259816; FTO rs9939609; and LEP rs7799039. We used logistic regressions to test the effect of each locus on T2D in two case⁻control groups with obesity and without obesity. Also, linear regression models on glucose and glycated hemoglobin (HbA1c) were carried out on the whole sample, adjusted by age, gender, and body mass index. Results: The CXCL12 rs501120 C allele (OR = 1.96, p = 0.02), the FTO rs9939609 A allele (OR = 2.20, p = 0.04) and the LEP rs7799039 A allele (OR = 0.6, p = 0.03) were significantly associated with T2D in obesity case⁻control group. No significant association was found in the non-obesity case⁻control group. The linear regression model showed that CDNK2A/B rs1333049 C allele (β = 0.4, p = 0.03) and FTO rs9939609 A allele (β = 0.5, p = 0.03), were significantly associated with HbA1c, but no association was found among the loci with the glucose levels. Conclusions: Polymorphisms previously linked with obesity and cardiovascular events were also associated with T2D and high levels of HbA1c. Furthermore, we must point at the fact that this is the first report where polymorphisms CXCL12 rs501120 and LEP rs7799039 are associated with T2D in subjects with obesity.

Single-nucleotide polymorphisms in a cohort of significantly obese women without cardiometabolic diseases

BACKGROUND/OBJECTIVES

Obesity is an important risk factor for the development of diseases such as diabetes mellitus, hypertension, and dyslipidemia; however, a small number of individuals with long-standing obesity do not present with these cardiometabolic diseases. Such individuals are referred to as metabolically healthy obese (MHO) and potentially represent a subgroup of the general population with a protective genetic predisposition to obesity-related diseases. We hypothesized that individuals who were metabolically healthy, but significantly obese (BMI ≥ 35 kg/m2) would represent a highly homogenous subgroup, with which to investigate potential genetic associations to obesity. We further hypothesized that such a cohort may lend itself well to investigate potential genotypes that are protective with respect to the development of cardiometabolic disease.

SUBJECTS/METHODS

In the present study, we implemented this novel selection strategy by screening 892 individuals diagnosed as Class 2 or Class 3 obese and identified 38 who presented no manifestations of cardiometabolic disease. We then assessed these subjects for single-nucleotide polymorphisms (SNPs) that associated with this phenotype.

RESULTS

Our analysis identified 89 SNPs that reach statistical significance (p < 1 × 10-5), some of which are associated with genes of biological pathways that influences dietary behavior; others are associated with genes previously linked to obesity and cardiometabolic disease as well as neuroimmune disease. This study, to the best of our knowledge, represents the first genetic screening of a cardiometabolically healthy, but significantly obese population.

Prediction of Blood Lipid Phenotypes Using Obesity-Related Genetic Polymorphisms and Lifestyle Data in Subjects with Excessive Body Weight

Background and Aim

Individual lipid phenotypes including circulating total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and triglycerides (TG) determinations are influenced by gene-environment interactions. The aim of this study was to predict blood lipid level (TC, LDL-c, HDL-c, and TG) variability using genetic and lifestyle data in subjects with excessive body weight-for-height.

Methods

This cross-sectional study enrolled 304 unrelated overweight/obese adults of self-reported European ancestry. A total of 95 single nucleotide polymorphisms (SNPs) related to obesity and weight loss were analyzed by a targeted next-generation sequencing system. Relevant genotypes of each SNP were coded as 0 (nonrisk) and 1 (risk). Four genetic risk scores (GRS) for each lipid phenotype were calculated by adding the risk genotypes. Information concerning lifestyle (diet, physical activity, alcohol drinking, and smoking) was obtained using validated questionnaires. Total body fat (TFAT) and visceral fat (VFAT) were determined by dual-energy X-ray absorptiometry.

Results

Overall, 45 obesity-related genetic variants were associated with some of the studied blood lipids. In addition to conventional factors (age, sex, dietary intakes, and alcohol consumption), the calculated GRS significantly contributed to explain their corresponding plasma lipid trait. Thus, HDL-c, TG, TC, and LDL-c serum concentrations were predicted by approximately 28% (optimism-corrected adj. R² = 0.28), 25% (optimism-corrected adj. R² = 0.25), 24% (optimism-corrected adj. R² = 0.24), and 21% (optimism-corrected adj. R²=0.21), respectively. Interestingly, GRS were the greatest contributors to TC (squared partial correlation (PC²) = 0.18) and LDL-c (PC² = 0.18) features. Likewise, VFAT and GRS had a higher impact on HDL-c (PC² = 0.09 and PC² = 0.06, respectively) and TG levels (PC² = 0.20 and PC² = 0.07, respectively) than the rest of variables.

Conclusions

Besides known lifestyle influences, some obesity-related genetic variants could help to predict blood lipid phenotypes.

Association between leptin gene rs7799039 polymorphism and lipid profile changes induced by isotretinoin treatment in acne patients

Introduction

Isotretinoin, a vitamin A-derived medication, is one of the effective treatments for severe acne. However, in a fraction of patients, this treatment causes significant adverse effects. Leptin is a pro-inflammatory cytokine that plays a role in apoptosis of adipose cells and sebaceous lipid metabolism. Thus, genetic polymorphisms in the leptin (LEP) gene may modulate the response to isotretinoin therapy. Here, we explore the contribution of rs7799039 polymorphism of the LEP gene in the adverse effects of the oral isotretinoin therapy among acne patients.

Materials and methods

Clinical parameters were obtained from 200 patients before and after isotretinoin treatment for acne. In addition, circulatory lipid profile and aspartate transaminase (AST) and alanine aminotransferase (ALT) enzymes from acne subjects before and 1 month after oral isotretinoin treatment were also measured.

Results

An association between the rs7799039 polymorphism and the following lipid parameters: high-density lipoprotein (HDL) at baseline and after treatment, HDL % change, low-density lipoprotein % change and total cholesterol % change (P < 0.05). In addition, there was an association between the LEP polymorphism and higher AST and ALT at baseline and after treatment (P < 0.05).

Conclusion

In conclusion, rs7799039 LEP polymorphism might modulate lipid parameters and liver enzymes, but not other major side effects of oral isotretinoin therapy.