Common variants in LEPR, IL6, AMD1, and NAMPT do not associate with risk of juvenile and childhood obesity in Danes: a case-control study

Association between genetic polymorphisms of leptin receptor and preeclampsia in Chinese women

OBJECTIVE

Leptin signaling plays an important role in regulating metabolism and reproduction. In the present study, we investigated the relationship between polymorphisms of leptin receptor (LEPR) gene A223G and A668G and preeclampsia (PE) and evaluated influences of genotypes on clinical, metabolic, and oxidative stress indices in Chinese women.

METHODS

This is a case-control study including 322 patients with PE and 1295 healthy pregnant women. The two polymorphisms were genotyped by polymerase chain reaction-restriction fragments length polymorphism method. Clinical and biochemical parameters were analyzed.

RESULTS

The frequencies of the AA + AG genotypes (28.6% vs. 36.1%) and A allele (14.9% vs. 19.8%) of LEPR A223G polymorphism, and those of the AA + AG genotypes (17.7% vs. 24.6%) and A allele (9.0% vs. 12.9%) of LEPR A668G polymorphism were significantly lower in the PE group than those in the control group. The 223A and 668A alleles were protective factors against PE in the regression model, which included age and delivery body mass index as covariates (OR = 0.684, 95% CI: 0.506-0.926, p = .014; OR = 0.650, 95% CI: 0.456-0.927, p = .017, respectively). When the 668GG/223GG combined genotype served as the reference category, the 668A/223A combined allele had further enhanced the protective effect on PE (OR = 0.558, 95% CI: 0.374-0.833, p = .004). Patients possessing the LEPR 223A allele had higher total antioxidant capacity and lower oxidative stress index (p < .05), while those with the LEPR 668A allele had higher high-density lipoprotein cholesterol levels (p = .045) compared with those carrying the corresponding GG genotype.

CONCLUSIONS

The 223A and 668A alleles of LEPR polymorphisms are genetic protective factors for PE in Chinese women. The two alleles may exert a beneficial effect on oxidative stress and lipid metabolism in patients.

IL-6 Polymorphisms Are Not Related to Obesity Parameters in Physically Active Young Men

Interleukin 6 (IL-6) is a cytokine with both pro- and anti-inflammatory actions, but is also considered as a "metabolic hormone" involved in immune responses, affecting glucose, protein and lipid metabolism. It has been proposed to be related to obesity, but various results have been presented. Thus, in this study, the very homogenous population of young, male military professionals, living in the same conditions involving high physical activity, has been selected to avoid the influence of environmental factors. The subjects were divided into groups depending on the obesity parameters BMI (body mass index) and fat percentage (fat%), and the following IL-6 SNPs (Single Nucleotide Polymorphisms) were analyzed: rs1800795, rs1800796 and rs13306435. No relation was found between obesity parameters and IL-6 polymorphisms rs1800795, rs1800796 and rs13306435. It may be postulated that even if a genetic predisposition involves IL-6 genes, this effect in individuals with obesity of a low grade is minor, or can be avoided or at least markedly reduced by changes in lifestyle.

Association of interleukin-6 polymorphisms with obesity: A systematic review and meta-analysis

Obesity is a common metabolic disorder with increasing trend all around the world. Owing to the role of pro-inflammatory cytokines on obesity, we aimed to investigate the role of interleukin-6 (IL-6) polymorphisms on risk of obesity. Electronic literatures were searched in Web of Science, PubMed, Embase, and Scopus. The references of relevant reviews and included studies were also manually checked. All types of observational studies from 1 January 1992 to 28 February 2018 were included. Odds ratio (OR) was estimated by fixed and random effect model. Subgroup analysis was carried out based on age statues. Pooling analysis of eligible studies have been considered for rs2069845 and rs1800796, and no significant results were observed. Minor allele of IL-6 rs1800797polymorphism decreased the risk of obesity/overweight in allelic 0.74 (0.59-0.92), dominant 0.65 (0.49-0.85), and over-dominant 0.66 (0.51-0.87) models. Fourteen eligible studies were included for rs1800795. According to BMI, C allele showed increased risk of obesity in genetic models containing homozygote model 1.47 (1.02-2.12) for body mass index (BMI) ≥ 25 vs. BMI < 25, recessive model 1.32 (1.07-1.63) for BMI ≥ 30 vs. BMI < 25, and homozygote model 1.35 (1.10-1.66) for BMI ≥ 30 vs. BMI < 30. In overall definition of obesity more significant results were observed, including homozygote model in obese vs. normal 1.71 (1.14-2.56). Similarly, subgroups analysis revealed additional significant results. Minor alleles of rs1800795 raised and rs1800797 reduced the risk of obesity, while rs1800796 and rs2069845 may not be associated. However, more observational studies are recommended to confirm these results.

Food Consumption as a Modifier of the Association between LEPR Gene Variants and Excess Body Weight in Children and Adolescents: A Study of the SCAALA Cohort

No studies showing that food consumption is a modifier of the association of variants of the leptin receptor gene (LEPR) with body weight have involved a Brazilian population. The aim of this study was to evaluate the modifying effect of dietary intake on the association between the LEPR gene and excess weight. In this study, 1211 children and adolescents aged 4⁻11 years were assessed. Participants were genotyped for 112 single-nucleotide variants of the LEPR gene. Anthropometric measurements were performed, and dietary data were obtained. Logistic regressions were used to study the associations of interest. Of the participants, 13.4% were overweight/obese. The risk allele (G) of the rs1137100 variant was associated with excess weight in individuals with fat consumption below the median (odds ratio OR = 1.92; 95% confidence interval CI = 1.18⁻3.14), with daily frequency of consumption of drink/artificial juice (OR = 2.15; 95% CI = 1.26⁻3.68) and refined cereals (OR = 2.17; 95% CI = 1.31⁻3.62) above the median. The risk allele (G) of variant rs1177681 was also associated with excess weight (OR = 2.74; 95% CI = 1.65⁻4.57) in subjects with a daily frequency of refined cereal consumption above the median. The association between LEPR and excess weight can be modulated by the type and distribution of dietary fatty acids, sugary drinks, and refined cereals.

NAMPT serum levels are selectively elevated in acute infectious disease and in acute relapse of chronic inflammatory diseases in children

Nicotinamide phosphoribosyl transferase (NAMPT) is an inflammatory adipocytokine shown to interact in immune modulation in chronic inflammatory diseases, acute respiratory distress syndrome, sepsis, cancer and obesity in adulthood. It is, however, not clear whether this association reflects a chronic elevation or acute inflammatory response. We analyzed NAMPT concentrations in distinct states of inflammation in 102 children and found consistently significantly increased NAMPT levels in subjects with acute infections. NAMPT concentrations in children with stable chronic inflammatory diseases were not significantly different, whereas in patients with acute relapse of chronic disease NAMPT was significantly higher than in children in remission or healthy controls. In states of low-grade inflammation (children with atopic disease or obesity) we did not detect alterations in NAMPT serum levels. NAMPT correlated positively with inflammatory markers such as CRP. The most predictive factor for NAMPT serum concentrations was leucocyte count and therein the neutrophil count. Furthermore, systemic circulating NAMPT levels were closely associated with NAMPT release from corresponding cultured PBMCs. In conclusion, NAMPT is selectively increased in states of acute but not chronic inflammation in children. The close relationship between systemic circulating NAMPT with leucocyte counts and release indicate that leucocytes most probably are the source of inflammation related NAMPT levels.

Leptin Receptor Gene Variant rs11804091 Is Associated with BMI and Insulin Resistance in Spanish Female Obese Children: A Case-Control Study

Leptin is an endocrine hormone that has a critical role in body weight homoeostasis and mediates its effects via the leptin receptor (LEPR). Common polymorphisms in the genes coding leptin receptors have been associated with metabolic abnormalities. We assessed the association of 28 LEPR polymorphisms with body mass index (BMI) and their relationship with obesity-related phenotypes, inflammation and cardiovascular disease risk biomarkers. A multicentre case-control study was conducted in 522 children (286 with obesity and 236 with normal-BMI). All anthropometric, metabolic factors and biomarkers were higher in children with obesity except apolipoprotein (Apo)-AI, cholesterol, high-density lipoprotein cholesterol (HDL-c), and adiponectin, which were lower in the obesity group; and glucose, low-density lipoprotein cholesterol (LDL-c), and matrix metalloproteinase-9 that did not differ between groups. We identified the associations between rs11208659, rs11804091, rs10157275, rs9436303 and rs1627238, and BMI in the whole population, as well as the association of rs11804091, rs10157275, and rs1327118 with BMI in the female group, although only the rs11804091 remained associated after Bonferroni correction (p = 0.038). This single nucleotide polymorphisms (SNP) was also associated with insulin (p = 0.004), homeostasis model assessment for insulin resistance (HOMA-IR) (p = 0.006), quantitative insulin sensitivity check index (QUICKI) (p = 0.005) and adiponectin (p = 0.046) after adjusting for age, Tanner stage and BMI. Our results show a sex-specific association between the rs11804091 and obesity suggesting an influence of this SNP on insulin resistance.