The Impact of LEP G-2548A and LEPR Gln223Arg Polymorphisms on Adiposity, Leptin, and Leptin-Receptor Serum Levels in a Mexican Mestizo Population

Meta-analysis investigating the impact of the LEPR rs1137101 (A>G) polymorphism on obesity risk in Asian and Caucasian ethnicities

Obesity is a chronic condition which is identified by the buildup of excess body fat caused by a combination of various factors, including genetic predisposition and lifestyle choices. rs1137101 (A > G) polymorphism in the CHR1 domain of LEPR protein linked to different diseases including obesity. Nevertheless, the connection between this polymorphism and the likelihood of developing obesity has not been determined definitively. Therefore, a meta-analysis was conducted to assess the relationship between rs1137101 and the risk of obesity. The meta-analysis included all studies meeting pre-defined criteria, found through searching databases up until February 2023. A combined odds ratio with a 95% confidence interval was estimated as overall and in continent subgroups for homozygous, heterozygous, recessive, dominant and allelic models using the fixed or the random-effects model. The meta-analysis identified 39 eligible studies with cases and controls (6099 cases/6711 controls) in 38 articles under different ethnic backgrounds. The results indicated a significant relationship between rs1137101 and the likelihood of developing obesity in each of the genetic models [the homozygous model (GG vs. AA: 95% Confidence Interval = 1.12-1.73, Odds Ratio = 1.39, P value = 0.003); the heterozygous model (AG vs. AA: 95% Confidence Interval = 1.07-1.42, Odds Ratio = 1.23, P value = 0.005); the dominant model (AG/GG vs AA: 95% Confidence Interval = 1.10-1.49, Odds Ratio = 1.28, P value = 0.001); the recessive model (GG vs AA/AG: 95% Confidence Interval = 1.02-1.45, Odds Ratio = 1.21, P value = 0.03); and the allelic model (G vs A; 95% Confidence Interval = 1.07-1.33, Odds Ratio = 1.19, P value = 0.002)] tested. Additionally, with an FDR <0.05, all genotypic models demonstrated statistical significance. The association remained significant among subgroups of Asian and Caucasian populations, although analysis in some genetic models did not show a significant association. Begg's and Egger's tests did not show publication biases. In sensitivity analysis, one particular study was found to have an impact on the Recessive model's significance, but other models remained unaffected. The current meta-analysis found significant indications supporting the association between rs1137101 and obesity. To avail a deeper understanding of this association, future research should include large-scale studies conducted in diverse ethnic populations.

Association of the Human Leptin Receptor Gene (rs1137101; Gln223Arg) Polymorphism and Circulating Leptin in Patients with Metabolic Syndrome in the Indian Population

Phenotypic expression of metabolic syndrome is precipitated by environmental variables along with the individual genetic susceptibility to the obesogenic environment and growing body of evidence suggest a paramount role of adipocytokines. Therefore, identifying the genetic influence on circulation leptin levels and clarifying genotype-phenotype correlation of rs1137101 {Leptin receptor gene (LEPR) Gln223Arg (Q223R; A668G)} in metabolic syndrome were the primary objective of this study. A total of 447 adult participants, including 214 metabolic syndrome patients and 233 healthy controls, were genotyped using polymerase chain reaction-restriction fragment length polymorphism method to unravel the effects of genetic risk loci {Leptin receptor gene; Gln223Arg (Q223R; A668G); rs1137101} on the occurrence of metabolic syndrome in consort with circulation leptin levels. Suitable descriptive statistics was used for different variables. The genotype frequencies were found to be in Hardy-Weinberg equilibrium for both cases (p > 0.2722) as well as in controls (p > 0.2331). However, genotype (x2: 11.26, 2 d.f. p = 0.0036) and allele distribution (x2: 10.51, 2 d.f. p: 0.0012) of the LEPR Gln223Arg (Q223R; A668G) differed significantly between cases and controls. Gln/Arg genotype (OR = 1.6099; 95% CI = 1.0847-2.3893; p value = 0.0181), Arg/Arg genotype (OR = 2.8121; 95% CI = 1.4103-5.6074; p value = 0.0033) and R allele (OR = 1.5875; 95% CI = 1.1996-2.1008; p value = 0.0012) were significantly associated with increased risk of metabolic syndrome in univariate analysis. Further a multivariate logistic regression adjusted for potential confounders showed that Arg/Arg genotype (OR = 1.9; 95% CI = 1.271-2.639; p-value < 0.05) and Gln/Arg (OR: 1.3; 95% CI = 0.873-2.034; p value < 0.05) have a significant risk for the occurrence of the metabolic syndrome. A progressive increase in the serum leptin levels from major homozygous alleles to minor homozygous alleles were observed indicating that rs1137101 modify the serum leptin concentrations in patients with metabolic syndrome. These findings provide enough evidence of a significant association of LEPR Gln223Arg (Q223R; A668G) polymorphism in the LepR gene in Indian patients with increased risk of metabolic syndrome for R allele and Arg/Arg homozygote. Thus, rs1137101 might be a pleiotropic locus for metabolic syndrome and its components in studied population.

A Case-Control Study of the Association of Leptin Gene Polymorphisms with Plasma Leptin Levels and Obesity in the Kerala Population

BACKGROUND

Over the last few years, the importance of leptin in energy metabolism has been extensively studied in both animal models and in humans. Very few results are available on the association between human leptin gene (LEP) variants and obesity traits in India. We designed this study to analyse the polymorphisms in human leptin gene and the association of sequence variants with obesity among the population in Kerala, South India.

METHODS

In this case-control design of 148 study participants, data were collected on socioeconomic aspects and anthropometric measurements. Plasma glucose, insulin, leptin, and lipid profile were measured. Genotyping was done by automated DNA sequencing.

RESULTS

The common Single Nucleotide Polymorphism (SNP) of 5'-UTR of LEP - 2548G/A was found to be present in the study population with "A" variant as dominant allele. A novel synonymous mutation Thr5Thr of exon 2 of LEP was identified in heterozygous form in one subject with morbid obesity with hyperleptinemia. A novel missense mutation Phe17Leu was observed in two subjects with obesity in heterozygous condition. A novel missense mutation Lys36Arg in exon 2 of LEP was observed in one subject with abdominal obesity and decreased serum leptin level.

CONCLUSION

LEP - 2548G/A at 5'-untranslated region was found to be common with the mutant "A" variant in the study population. SNPs of exons in LEP were found to be rare but associated with morbid obesity and altered levels of serum leptin in the study population in Kerala, India.

Resistin levels decrease as insulin resistance increases in a Mexican-American cohort

AIMS

Links between resistin, insulin resistance (IR), and resistin-stimulated cytokine signaling remain unknown in Mexican-Americans. A Mexican-American cohort was examined to determine (1) relationships between circulating resistin and IR, (2) resistin's associations with cytokines and demographic and anthropometric variables, and (3) similar measurements with other adipokines.

METHODS

For cross sectional analyses, 953 adults (367 males and 586 females) in the Cameron County Hispanic Cohort (CCHC) were stratified into three groups: normal glucose tolerance, prediabetes, and diabetes mellitus. Differences in resistin and other adipokine levels were examined using linear regression via unadjusted model (Model 1), model adjusted for cytokines (Model 2), and model further adjusted for demographic and anthropometric variables (Model 3).

RESULTS

HOMA-IR increased with worsening glucose tolerance (p < 0.0001). In all models, resistin significantly decreased as glucose tolerance deteriorated. Model 3 resistin was positively associated with IL-1β (p = 0.0252) and IL-8 (p < 0.0001), inversely associated with TNF-α (p = 0.0352), but nonsignificantly associated with IL-6 (p = 0.8671). Model 3 leptin was significantly lower in diabetes mellitus compared to other groups (p < 0.005) and positively associated with female sex (p < 0.0001), age (p = 0.024), and BMI (p < 0.0001), without significant cytokine associations. Adiponectin displayed no significant associations with glucose tolerance, but was significantly associated with sex, BMI, and lipids (Model 3).

CONCLUSIONS

Resistin unexpectedly decreased as IR increased while supporting evidence of a resistin-stimulated cytokine pathway in this Mexican-American cohort. Leptin fell with elevated IR after adjusting for cytokines, demographic and anthropometric variables. Adiponectin nonsignificantly decreased as IR increased while showing significant associations with sex, BMI, and lipids.

Lifestyle Genetics-Based Reports in the Treatment of Obesity

Obesity becomes a chronic disease due to the increasing number of mortality and morbidity cases around the world. In most regions, chronic illnesses, such as obesity, are important sources of morbidity and mortality. Due to a lack of effective strategies for prevention and management, the adverse effects of obesity and related diseases on health continue to be a serious problem. Relevant information was searched from Google Scholar, Scopus, and PubMed using such different terms as "Obesity", "Obesity Management", "Obesity AND Physical activity", "Obesity AND Genetics", "Obesity AND Diet", and "Obesity AND Nutrigenomics". Obesity is characterized by a complex interaction of hereditary and lifestyle factors, which includes food. Diet is an environmental element that plays an important and considerable role in the management of health and reduces the risk of obesity and its comorbidities. Changes in lifestyle patterns not only help burn extra calories but also prevent the development of obesity via its modulating effect on genetic factors. Different people respond differently to an obesogenic environment. The notion of nutrigenetics emerged as a result of various genetic variations that may explain this heterogeneity. Nutritional genomics, also known as nutrigenetics, is the study that investigates and analyses gene variations linked to varied responses to certain foods; moreover, it links this variation to diseases, such as obesity. As a result, tailored nutrition advice based on a person's genetic profile may improve the outcomes of a specific dietary strategy and offer a novel dietary strategy to improve life quality and preventing obesity. This study concluded that physical activity and dietary interventions play an effective role in the management of obesity. Moreover, understanding of the function of the most prominent obesity-related genes, as well as the interaction between nutrition and gene expression, will help researchers design personalized treatment strategies for humans.

Associations of MC4R, LEP, and LEPR Polymorphisms with Obesity-Related Parameters in Childhood and Adulthood

MC4R, LEP, and LEPR genes are involved in the hypothalamic leptin-melanocortin regulation pathway, which is important for energy homeostasis. Our study aimed to evaluate the associations between the MC4R rs17782313, LEP rs7799039, and LEPR rs1137101 polymorphisms with obesity-related parameters in childhood and adulthood. The data were obtained from the Kaunas Cardiovascular Risk Cohort study, which started in 1977 with 1082 participants aged 12-13 years. In 2012-2014, the follow-up survey was carried out. Genotype analysis of all respondents (n = 509) aged 48-49 years was performed for the gene polymorphisms using Real-Time Polymerase Chain Reaction. Anthropometric measurements were performed in childhood and adulthood. In childhood, only skinfold thicknesses were associated with gene variants being the lowest in children with MC4R TT genotype and LEP AG genotype. In adulthood, odds of obesity and metabolic syndrome was higher in MC4R CT/CC genotype than TT genotype carriers (OR 1.8; 95% CI 1.2-2.8 and OR 1.6; 95% CI 1.1-2.4, respectively). In men, physical activity attenuated the effect of the MC4R rs17782313 on obesity. The LEP GG genotype was associated with higher BMI, waist circumference, and visceral fat level only in men. No associations of the LEPR rs1137101 polymorphisms with anthropometric measurements and leptin level were found. In conclusion, the associations of the MC4R and LEP gene polymorphisms with obesity-related parameters strengthened with age.

LEP (-2548G>A LEP) and LEPR (223Gln>Arg, 109Lys>Arg) polymorphisms as breast cancer risk factors in the Polish female population

On a global scale, breast cancer is the most common type of cancer in women, and it is still a growing problem. Therefore, new prognostic or diagnostic markers are required that would facilitate the assessment of patients or provide more efficient therapy, respectively. In these studies, we analyzed the contribution of LEP (2548G>A) and LEPR (109 Lys>Arg and 223Gln>Arg) genes polymorphisms to the risk of breast cancer development. The study involved 209 women aged 59.6 ± 11 years diagnosed with breast cancer and 202 healthy women aged 57.8 ± 8.2 years, who were blood donors. Polymorphism were evaluated by PCR–RFLP reaction followed by the verification of part of the samples by sequencing. The results of the study confirmed obesity as a significant breast cancer development risk factor in Polish women. However, no significant association between the studied polymorphisms and breast cancer risk or severity of the neoplastic disease was found. Interestingly, it was shown that wild type 223Gln>Gln leptin receptor (LEPR) was statistically more common in women with human epidermal growth factor receptor 2 negative (HER2−) than human epidermal groth factor receptor 2 positive (HER2+) breast cancer and wild type form of 2548G>A LEP was more common in women with progesterone receptor positive (PR+) than progesterone receptor negative (PR−) breast cancer. Studied polymorphisms of the LEP and LEPR genes do not increase breast cancer risk in the population of Polish women. However, they can affect PR an HER receptors expression and thus the severity of the disease. Noteworthy, this interesting correlation is being reported for the first time and might constitute an essential contribution to the identification of molecular mechanisms of carcinogenesis.

Leptin Levels and Q223R Leptin Receptor Gene Polymorphism in Obese Mexican Young Adults

INTRODUCTION

The Q223R polymorphism of the leptin receptor (LEPR) gene is one of the most common polymorphisms and it is believed to be associated with a damaged capacity of LEPR signaling and with high circulating leptin levels.

METHODS

An observational, cross-sectional, analytical study was carried out in the Autonomous University of Ciudad Juarez, Mexico, where a sample of young adult participants (ranging from 18 to 30 years of age) was obtained. They were classified based on the results of body mass index: non-obese, and overweight/obese. The polymorphic variant was determined by Polymerase Chain Reaction (PCR) from the DNA sample and serum leptin levels were measured by Enzyme-Linked Immuno Sorbent Assay.

RESULTS

A total of 159 participants were included (non-obese, n=103; overweight/obese, n=56). Leptin levels were 15.14±12.3 ng/mL in the non-obese group and 26.13±19.0 ng/mL in the overweight/obese group (p≤0.001). The allelic frequencies of the Q and R alleles of the LEPR gene in the studied subjects were as follows: non-obese, Q=0.56, R=0.44; overweight/obese, Q=0.62, R=0.38. The relative risk for the Q/Q genotype was 1.18 (Cl 0.53-2.34), for Q/R was 1.14 (Cl 0.59-2.18) and for R/R was 0.59 (Cl 0.23-1.50).

CONCLUSIONS

This study shows that leptin levels are associated with overweight/obesity in Mexican young adults, but this is not related to the presence of the Q223R polymorphism in the LEPR gene, so the underlying mechanisms for a possible disturbance in leptin signaling in obese Mexican young adults await further studies.

Characterization of genetic and phenotypic heterogeneity of obstructive sleep apnea using electronic health records

Background

Obstructive sleep apnea (OSA) is defined by frequent episodes of reduced or complete cessation of airflow during sleep and is linked to negative health outcomes. Understanding the genetic factors influencing expression of OSA may lead to new treatment strategies. Electronic health records (EHRs) can be leveraged to both validate previously reported OSA-associated genomic variation and detect novel relationships between these variants and comorbidities.

Methods

We identified candidate single nucleotide polymorphisms (SNPs) via systematic literature review of existing research. Using datasets available at Geisinger (n = 39,407) and Vanderbilt University Medical Center (n = 24,084), we evaluated associations between 40 previously implicated SNPs and OSA diagnosis, defined using clinical codes. We also evaluated associations between these SNPs and OSA severity measures obtained from sleep reports at Geisinger (n = 6571). Finally, we used a phenome-wide association study approach to help reveal pleiotropic genetic effects between OSA candidate SNPs and other clinical codes and laboratory values available in the EHR.

Results

Most previously reported OSA candidate SNPs showed minimal to no evidence for associations with OSA diagnosis or severity in the EHR-derived datasets. Three SNPs in LEPR, MMP-9, and GABBR1 validated for an association with OSA diagnosis in European Americans; the SNP in GABBR1 was associated following meta-analysis of results from both clinical populations. The GABBR1 and LEPR SNPs, and one additional SNP, were associated with OSA severity measures in European Americans from Geisinger. Three additional candidate OSA SNPs were not associated with OSA-related traits but instead with hyperlipidemia and autoimmune diseases of the thyroid.

Conclusions

To our knowledge, this is one of the largest candidate gene studies and one of the first phenome-wide association studies of OSA genomic variation. Results validate genetic associates with OSA in the LEPR, MMP-9 and GABBR1 genes, but suggest that the majority of previously identified genetic associations with OSA may be false positives. Phenome-wide analyses provide evidence of mediated pleiotropy. Future well-powered genome-wide association analyses of OSA risk and severity across populations with diverse ancestral backgrounds are needed. The comprehensive nature of the analyses represents a platform for informing future work focused on understanding how genetic data can be useful to informing treatment of OSA and related comorbidities.

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.

Candidate Gene and Genome-Wide Association Studies for Circulating Leptin Levels Reveal Population and Sex-Specific Associations in High Cardiovascular Risk Mediterranean Subjects

Leptin is a hormone crucial in the regulation of food intake and body-weight maintenance. However, the genes and gene variants that influence its plasma levels are still not well known. Results of studies investigating polymorphisms in candidate genes have been inconsistent, and, in addition, very few genome-wide association studies (GWAS) have been undertaken. Our aim was to investigate the genes and gene variants most associated with plasma leptin concentrations in a high-cardiovascular-risk Mediterranean population. We measured plasma leptin in 1011 men and women, and analyzed the genetic factors associated using three approaches: (1) Analyzing the single nucleotide polymorphisms (SNPs) reported in a GWAS meta-analysis in other populations (including an SNP in/near each of these LEP, SLC32A1, GCKR, CCNL, COBLL1, and FTO genes); (2) Investigating additional SNPs in/near those genes, also including the RLEP gene; and (3) Undertaking a GWAS to discover new genes. We did not find any statistically significant associations between the previously published SNPs and plasma leptin (Ln) in the whole population adjusting for sex and age. However, on undertaking an extensive screening of other gene variants in those genes to capture a more complete set of SNPs, we found more associations. Outstanding among the findings was the heterogeneity per sex. We detected several statistically significant interaction terms with sex for these SNPs in the candidate genes. The gene most associated with plasma leptin levels was the FTO gene in men (specifically the rs1075440 SNP) and the LEPR in women (specifically the rs12145690 SNP). In the GWAS on the whole population, we found several new associations at the p < 1 × 10^-5 level, among them with the rs245908-CHN2 SNP (p = 1.6 × 10^-6). We also detected a SNP*sex interaction at the GWAS significance level (p < 5 × 10^-8), involving the SLIT3 gene, a gene regulated by estrogens. In conclusion, our study shows that the SNPs selected as relevant for plasma leptin levels in other populations, are not good markers for this Mediterranean population, so supporting those studies claiming a bias when generalizing GWAS results to different populations. These population-specific differences may include not only genetic characteristics, but also age, health status, and the influence of other environmental variables. In addition, we have detected several sex-specific effects. These results suggest that genomic analyses, involving leptin, should be estimated by sex and consider population-specificity for more precise estimations.

Association of single nucleotide polymorphisms of adiponectin and leptin genes with breast cancer

Single nucleotide polymorphisms (SNPs) in adiponectin gene [rs1501299 (+276G/T) and rs266729 (-11377C/G)] and one SNP of leptin gene [rs7799039 (-2548G/A)] are known to influence plasma levels of adiponectin and leptin respectively. Literature is scarce on the association of adiponectin gene polymorphism rs266729 with breast cancer. The present study was taken up to study these polymorphisms and their association with breast cancer. Ninety-three patients diagnosed with malignant breast cancer were included as cases along with 186 age matched healthy controls. Adiponectin +276G/T, -11377C/G and leptin -2548G/A polymorphism were studied using polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP). Adipokine levels in blood were measured using enzyme linked immunosorbent assay. Adiponectin +276G/T and leptin -2548G/A showed a significant increased risk for breast cancer even after adjusting for confounding variables like present age, age at menarche, age at first child birth and age at menopause. In the subset analysis, based on menopausal state, stronger association was observed between SNP in adiponectin gene +276G/T with the breast cancer in post-menopausal women after adjusting for all other variables. No association was found with adiponectin -11377C/G. No association of the gene polymorphisms with adipokine levels was observed. Also, no significant association was seen for the effect of gene-environment interaction i.e. presence of polymorphism with obesity and menopausal state for any of the SNPs studied. Adiponectin +276G/T is strongly associated with breast cancer in postmenopausal women while leptin -2548G/A polymorphisms is significantly associated with breast cancer irrespective of the menopausal state in south Indian subjects.

Variability in the leptin receptor gene and other risk factors for post-transplant diabetes mellitus in renal transplant recipients

Aim: Post-transplant diabetes mellitus (PTDM) is one of the main complications after kidney transplantation. It is known that leptin plays an important role in glucose metabolism and mutations in the leptin receptor gene (LEPR) are responsible for different complications in renal transplant recipients. We aimed to analyse the association of polymorphisms in LEPR with the development of PTDM in these patients. Methods: A total of 315 renal transplant recipients were genotyped for the Lys109Arg, Gln223Arg and Lys656Asn polymorphisms. The impact of these genetic variables together with other clinical and demographic parameters on PTDM risk was evaluated in a multivariate regression analysis. Results: The 223Arg variant showed a significant association with PTDM risk [OR = 3.26 (1.35-7.85), p = 0.009] after correcting for multiple testing. Carriers of this variant also showed higher BMI values (26.95 ± 4.23) than non-carriers (25.67 ± 4.43, p = 0.025). In addition, it was BMI at transplant and not the BMI increment in the first year after grafting that was associated with PTDM (p > 0.00001). Haplotype analyses did not reveal significant associations. Conclusions: Our result show, for the first time to our knowledge, that genetic variability in the LEPR may contribute significantly to the risk for PTDM in renal transplant recipients. KEY MESSAGES The LEPR Gln223Arg polymorphism significantly contributes to the development of PTDM in renal transplant recipients. The effect of the 223Arg variant on PTDM is strongly modulated by the age of the recipient. The 223Arg variant in the leptin receptor is related to higher BMI in renal transplant recipients.

Obesity phenotype in relation to gene polymorphism among samples of Egyptian children and their mothers

Obesity is complex heterogeneous disease controlled by genes, environmental factors, and their interaction. Genetic factors account for 40-90% of the body mass index variations. Body mass index (BMI) of children correlates more closely with maternal than paternal BMI. So, this studu was aimed to investigate the role of leptin receptor LEPR Gln223Arg, the uncoupling protein 2 (UCP2 G 866 A) and insulin receptor gene (INSR exon 17) polymorphisms in the pathogenesis of obesity. A cross-sectional study executed on 130 children and their obese mothers; classified into 2 groups according to their BMI. The 2 groups were evaluated regarding the anthropometry. Restriction fragment length analysis for LEPR Gln223Arg, UCP2 -866 G/A and INSR exon 17 polymorphisms were applied. It was reported that increased risk of obesity was found in LEPR AG + AA genotype and the A allele. Significant statistical difference was detected only in female children. Concerning UCP2, the AG followed by the GG genotype was the most frequent in all groups and the G allele was the mostly present in obese mothers and obese male children but with no statistical significance. There was difference in the INSR genotype and alleles between groups, but this difference was not statistically significant. This study concluded that the LEPR Gln223Arg, UCP2 G 866 A and INSR exon 17 polymorphisms are related to obesity in Egyptian population. Further researches on larger population are recommended to ascertain the implications of LEPR, UCP2 and INSR polymorphisms in obesity.

The Gene-Lifestyle Interaction on Leptin Sensitivity and Lipid Metabolism in Adults: A Population Based Study

Background: Obesity has been associated with leptin resistance and this might be caused by genetic factors. The aim of this study was to investigate the gene-lifestyle interaction between −866G/A UCP2 (uncoupling protein 2) gene polymorphism, dietary intake and leptin in a population based study. Methods: This is a cross sectional study conducted in adults living at urban area of Yogyakarta, Indonesia. Data of adiposity, lifestyle, triglyceride, high density lipoprotein (HDL) cholesterol, leptin and UCP2 gene polymorphism were obtained in 380 men and female adults. Results: UCP2 gene polymorphism was not significantly associated with adiposity, leptin, triglyceride, HDL cholesterol, dietary intake and physical activity (all p > 0.05). Leptin was lower in overweight subjects with AA + GA genotypes than those with GG genotype counterparts (p = 0.029). In subjects with AA + GA genotypes there was a negative correlation between leptin concentration (r = −0.324; p < 0.0001) and total energy intake and this correlation was not seen in GG genotype (r = −0.111; p = 0.188). Conclusions: In summary, we showed how genetic variation in −866G/A UCP2 affected individual response to leptin production. AA + GA genotype had a better leptin sensitivity shown by its response in dietary intake and body mass index (BMI) and this explained the protective effect of A allele to obesity.

Circulating leptin, soluble leptin receptor, free leptin index, visfatin and selected leptin and leptin receptor gene polymorphisms in sporadic breast cancer

Leptin and visfatin are implicated in breast cancer risk but studies accounting for bioavailability of leptin are sparse. Reports on the association of leptin gene (LEP) and leptin receptor gene (LEPR) polymorphisms with breast cancer are also inconsistent. Only a very few studies have examined biochemical and genetic variables concomitantly in the same cohort. A matched pairs study was carried out to ascertain whether plasma leptin, soluble leptin receptor, free leptin index (leptin/soluble leptin receptor), serum visfatin and selected LEP and LEPR polymorphisms are risk factors for sporadic breast cancer. Newly diagnosed sporadic breast cancer patients (N=80) were matched for age, body mass index (BMI) and menopausal status with healthy controls. Plasma leptin, soluble leptin receptor and serum visfatin were measured by enzyme-immunoassay. LEP -2548 A/G and LEPR K109R, LEPR Q223R polymorphisms were determined by genotyping. Leptin (p=0.0234), leptin/BMI (p=0.0468), free leptin index (p<0.0001) and visfatin (p=0.0002) were significantly higher and soluble leptin receptor (p<0.0001) was significantly lower in patients. LEPR gene K109R A/G polymorphism increased breast cancer risk (odds ratio: 4.125). Multivariate analysis confirmed that leptin, soluble leptin receptor, free leptin index and G109 (R109) allele of the LEPR gene K109R polymorphism are risk factors for breast cancer. When stratified by menopausal status free leptin index and soluble leptin receptor remained as risk factors irrespective of menopausal status while LEPR gene K109R A/G polymorphism remained as a risk factor only in the postmenopausal group.

LEP rs7799039, LEPR rs1137101, and ADIPOQ rs2241766 and 1501299 Polymorphisms Are Associated With Obesity and Chemotherapy Response in Mexican Women With Breast Cancer

BACKGROUND

Obesity plays a major role in the pathogenesis of breast cancer. Leptin (LEP) and adiponectin (ADIPOQ) are important in the regulation of adipose tissue. The response to cancer treatment depends on the histological and molecular tumor type, clinical stage, and genetic variability that might promote carcinogenic development. The aim of this study was to investigate the association between overweight/obesity and polymorphisms in the LEP (rs7799039), LEP receptor (LEPR; rs1137101), and ADIPOQ genes (rs2241766, rs1501299) with the response to breast cancer treatment in Mexican women.

PATIENTS AND METHODS

A sample of 177 patients with primary breast cancer (stage I-III) and who received neoadjuvant therapy were included. Polymorphisms were genotyped and their serum LEP concentrations (n = 59) were quantified.

RESULTS

The patients' median age was 53.1 years, the frequency of overweight and obesity was 57 and 84 patients, respectively, 117 were postmenopausal, and 64 of the patients did not respond to chemotherapy. An association of the LEP rs7799039, LEPR rs1137101, and ADIPOQ rs1501299 polymorphisms with overweight/obesity was found. The patients who did not respond to treatment were more frequently obese, at clinical stage III, had metastases, and high levels of glucose. Moreover, in samples that were positive for estrogen receptor, higher levels of LEP were found, and in wild type genotypes for LEP rs7799039 and LEPR rs1137101.

CONCLUSION

There was a direct association between the polymorphisms in LEP rs7799039 and ADIPOQ rs1501299 with overweight/obesity, and these genotypes affected the response to chemotherapeutic treatment, suggesting that an obesogenic microenvironment is more favorable for tumoral progression.