Association of the rs17782313, rs17773430 and rs34114122 Polymorphisms of/near MC4R Gene with Obesity-Related Biomarkers in a Spanish Pediatric Cohort.

Obesity is a multifactorial disease whose onset and development are shaped by the individual genetic background. The melanocortin 4 receptor gene (MC4R) is involved in the regulation of food intake and energy expenditure. Some of the single nucleotide polymorphisms (SNPs) of this gene are related to obesity and metabolic risk factors. The present study was undertaken to assess the relationship between three polymorphism SNPs, namely, rs17782313, rs17773430 and rs34114122, and obesity and metabolic risk factors. One hundred seventy-eight children with obesity aged between 7 and 16 years were studied to determine anthropometric variables and biochemical and inflammatory parameters. Our results highlight that metabolic risk factors, especially alterations in carbohydrate metabolism, were related to rs17782313. The presence of the minor C allele in the three variants (C-C-C) was significantly associated with anthropometric measures indicative of obesity, such as the body mass and fat mass indexes, and increased the values of insulinemia to 21.91 µIU/mL with respect to the wild type values. Our study suggests that the C-C-C haplotype of the SNPs rs17782313, rs17773430 and rs34114122 of the MC4R gene potentiates metabolic risk factors at early ages in children with obesity.

Reduced Free Fatty Acid Receptor 4 Gene Expression is Associated With Extreme Obesity and Insulin Resistance in Children.

OBJECTIVES: Free fatty acid receptor 4 (FFAR4) is a G-protein-coupled membrane receptor highly expressed in macrophages that triggers anti-inflammatory effects and promotes insulin sensitization. We have previously found significant associations between the FFAR4 rs11187533 single nucleotide polymorphism (SNP) and various obesity comorbidity parameters. We aimed to verify the FFAR4 expression levels in children with obesity and the associated comorbidities. METHODS: Thirty-eight children with obesity were studied. Clinical and anthropometric evaluation was performed. A venous sample under fasting conditions was obtained. Biochemical study included parameters of metabolic risk. DNA was extracted and genotyped for the rs11187533 FFAR4 SNP. Real-time PCR technique was performed to investigate the gene expression. Relative FFAR4 mRNA levels were determined according to the 2-ΔΔCt method. RESULTS: Significant differences in FFAR4 expression levels between the CC and CT-TT genotypes of the rs11187533 FFAR4 SNP were observed (P = 0.034). The minor allele T presented higher levels of FFAR4 expression. We found that a loss of FFAR4 expression was associated with extreme obesity (P = 0.032). The lowest FFAR4 expression levels were observed in children who had higher insulin (P = 0.008) and homeostasis model assessment insulin resistance values (P = 0.012) and lower quantitative insulin-sensitivity check index (P = 0.033). CONCLUSIONS: The underexpression of FFAR4 was associated with extreme obesity and parameters indicative of obesity comorbidities in children. This under expression could be partially influenced by the presence of the C allele rs11187533 FFAR4 SNP.

Melatonin Levels in Children with Obesity Are Associated with Metabolic Risk and Inflammatory Parameters.

Melatonin, the hormone of circadian rhythm regulation, is involved in the modulation of mitochondrial activity through its antioxidant and anti-inflammatory properties. Alteration of circadian rhythms such as sleep is related to obesity and metabolic pathogenesis in adulthood, but studies during childhood are scarce. The present study investigated the association of melatonin with metabolic and inflammatory markers in children with (n = 113) and without obesity (n = 117). Melatonin was measured in saliva four and two hours before bedtime, and after one hour of sleep. Cardiometabolic factors, high sensitivity C-reactive protein, immune markers (monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, tumor necrosis α and interferon-γ), leptin and ghrelin were determined. Sleep duration was recorded by a questionnaire. The melatonin level at 1 h after sleep was found to be increased more than twofold in children with obesity (90.16 (57.16-129.16) pg/mL) compared to controls (29.82 (19.05-61.54) pg/mL, p < 0.001) and was related to fat mass (rho = 0.294, p < 0.001); melatonin levels at 1 h after sleep were inversely correlated with high-density lipoprotein cholesterol. Positive correlation was found with apolipoprotein B, adipokines, high sensitivity C-reactive protein, plasminogen activator inhibitor-1 and tumor necrosis factor-α. Shorter sleep duration and earlier waking times were recorded in children with obesity. In conclusion, melatonin in children with obesity appears to be involved in the global metabolic and inflammatory alteration of this condition.

Vitamin D receptor gene ApaI and FokI polymorphisms and its association with inflammation and oxidative stress in vitamin D sufficient Caucasian Spanish children.

BACKGROUND: Vitamin D has gone from being just one vitamin to being an important prohormone with multiple effects on different tissue types. The mechanism of action of the active form or calcitriol is mediated by the intracellular vitamin D receptor (VDR). The interaction of the VDR with calcitriol modulates the expression of target genes involved in cell proliferation and cytokine production. Several studies have explored the effects of vitamin D deficiency in inflammatory disorders. Furthermore, some mutations in the VDR can affect its functionality. The focus of this study was to explore associations between VDR single nucleotide polymorphisms (SNPs) and markers of inflammation and oxidative stress in vitamin D sufficient children. METHODS: This is a cross-sectional study of a Caucasian Spanish population including 155 healthy children (87 males, 68 females) aged 10 to 14 years. FokI, ApaI and TaqI SNPs of the VDR gene were genotyped. Routine biochemistry, serum levels of interleukin-6, tumor necrosis factor-α, interferon-γ, 8-isoprostaglandin F2α and nitrates were determined. RESULTS: The homozygous major allele AA in the FokI SNP was associated with increased levels of high-density lipoprotein cholesterol in a recessive inheritance mode (P=0.025). The minor allele A of ApaI was significantly associated with decreased serum tumor necrosis factor-α and 8-isoprostaglandin F2α in an additive mode (P=0.016 and P=0.020 respectively). No significant associations were observed between the TaqI SNP and any of the parameters evaluated. Haplotype analysis confirmed the significance of the relationships between ApaI and FokI SNPs and parameters associated with inflammation and oxidative stress. CONCLUSIONS: Genetic variations of VDR are associated with subtle changes in metabolic, inflammatory and oxidative stress markers. These results may provide a better understanding of the relationships between vitamin D and these clinical parameters.

Melatonin Content of Human Milk: The Effect of Mode of Delivery.

Objective: Cesarean section rates are increasing in developed countries and could be performed as an emergency or elective procedure. Our research aim was to determine whether elective cesarean section influences the melatonin content, the main circadian hormone, in human milk. Methods: Twenty-one women after vaginal delivery and 18 women after elective cesarean section were included. Only healthy mothers with normal newborns exclusively breastfed were recruited. Two samples of human milk were collected for each woman at three stages of lactation: colostrum, transitional milk, and mature milk; at each stage, one daytime sample and another nighttime sample were obtained. In total, 228 milk samples were studied. The melatonin content was analyzed by enzyme-linked immunosorbent assay. Results: Melatonin rhythmicity with higher melatonin content at night was maintained at each of the three stages of lactation, regardless of the type of delivery. A higher melatonin content was found in daytime colostrum after cesarean section with respect to colostrum obtained from mothers after vaginal delivery (30.3 pg/mL versus 14.7 pg/mL, p = 0.020). Melatonin content decreased progressively throughout the course of lactation in both groups. This decrease was significant when comparing transitional milk to colostrum in the cesarean group, both in the daytime (p = 0.016) and nighttime samples (p = 0.048). Conclusions: Cesarean section is associated with an increase in daytime colostrum melatonin. No difference was observed in mature milk with respect to vaginal delivery. Melatonin values in human milk decrease during the first month of lactation and circadian rhythmicity was observed irrespective of the mode of delivery.

The rs11187533 C>T Variant of the FFAR4 Gene Is Associated with Lower Levels of Fasting Glucose and Decreases in Markers of Liver Injury in Children with Obesity.

INTRODUCTION: Genetic factors can modulate the development of associated comorbidities in obesity. It has been shown that loss-of-function variants of the free fatty acid receptor 4 (FFAR4) gene negatively affect obesity comorbidities such as insulin resistance and fatty liver disease. OBJECTIVE: To test the relationships of metabolic factors in children with obesity with variants of the FFAR4 gene. METHODS: We performed an association study of 3 single nucleotide polymorphisms (SNPs) of FFAR4 (rs10882273 T>C, rs12243124 T>C, and rs11187533 C>T) covering the last intron and last exon of FFAR4 in a cohort of 203 children with obesity. Cardiometabolic factors were determined, including parameters related to insulin resistance, liver injury, and high-sensitivity C-reactive protein as an inflammatory marker. RESULTS: Significant genotype - phenotype interactions occurred between the rs11187533 SNP and glucose levels (p = 0.011). Moreover, we identified 2 marginally significant associations between this SNP and the hepatic enzymes alanine aminotransferase (p = 0.022) and gamma-glutamyltransferase (p = 0.015). The homozygous minor allele genotype (TT) was associated with a decrease in glucose levels. CONCLUSION: The homozygous minor allele genotype of the rs11187533 SNP might be protective against metabolic consequences accompanying obesity and could allow the identification of metabolically healthy obese individuals at early ages.

The connection of circadian rhythm to inflammatory bowel disease.

Inflammatory bowel disease (IBD) comprises a group of chronic, immune system-mediated inflammatory diseases that primarily affect the gastrointestinal tract. The pathogenesis of the intestinal lesions in IBD remains elusive, but the inflammation process could be the result of dysfunction of the innate and adaptive immune systems induced by genetic and environmental factors. In recent years, research has demonstrated a connection between environmental stressors that can influence day-night variations, also called circadian rhythms, and digestive health. In this review, we focus on alterations in the complex interactions between intestinal mucosa, microbial factors, and the immune response in the intestinal milieu. We introduce the mechanisms that establish circadian rhythms and their regulation by the circadian rhythm genes. Evidence of circadian variation in the defense mechanisms of the intestine and its implication in the maintenance of a healthy microbiota are presented. Disruption of the circadian system can increase the activity of the gut immune system and the release of inflammatory factors. The link between chronodisruption or circadian rhythm impairment and IBD demonstrated by experimental and clinical studies illustrates the potential impact of circadian rhythms on treatment of these diseases. Future studies that investigate aspects of this subject are warranted.

Bifidobacterium pseudocatenulatum CECT 7765 supplementation improves inflammatory status in insulin-resistant obese children.

PURPOSE: The relationships between gut microbiota and obesity-related co-morbidities have been increasingly recognized. Low-grade inflammation may be the main factor in the pathogenesis of such disorders. We investigated the effect of the potential probiotic Bifidobacterium pseudocatenulatum CECT 7765 on cardiometabolic risk factors, inflammatory cytokines and gut microbiota composition in obese children with insulin resistance. METHODS: The study included 48 obese children (10-15 years old) with insulin resistance. They received dietary advice and were assigned to take the capsules with or without probiotic (109-10 CFU) daily for 13 weeks. Clinical, biochemical and gut microbiome measurements were made at baseline and at the end of the intervention. RESULTS: There was a significant improvement in body mass index in all children after the intervention, suggesting that weight changes are related to the dietary advice. A significant decrease in circulating high-sensitive C-reactive protein (P = 0.026) and monocyte chemoattractant protein-1 (P = 0.032) and an increase in high-density lipoprotein cholesterol (P = 0.035) and omentin-1 (P = 0.023) in children receiving probiotic supplementation were observed compared to the control group. Regarding gut microbiota, probiotic administration significantly increased the proportion of the Rikenellaceae family members, particularly of the Alistipes genus. CONCLUSIONS: The beneficial effects of the intervention on inflammatory markers and lipid profile suggest that B. pseudocatenulatum CECT 7765 intake together with dietary recommendations can improve inflammatory status in children with obesity and insulin resistance. These effects are parallel to increases in bacterial groups associated with a lean phenotype. The modulation of gut microbiota with probiotic supplementation can be considered an effective tool to ameliorate some obesity-related disorders in children.

Association of RBP4 genetic variants with childhood obesity and cardiovascular risk factors.

BACKGROUND: Recent data suggest that retinol-binding protein 4 (RBP4) gene variants could be associated with a risk of obesity and its co-morbidities, such as metabolic syndrome, which increases the risk of developing type 2 diabetes mellitus and cardiovascular disease. OBJECTIVES: The present study examined the potential association of RBP4 single nucleotide polymorphisms (SNPs) with childhood obesity and its metabolic complications. METHODS: Four RBP4 SNPs, rs3758538 (3944A>C), rs3758539 (4406G>A), rs12265684 (12177G>C) and rs34571439 (14684T>G), were genotyped in a population of 180 Spanish Caucasian children (97 obese and 83 normal-weight children). Association of RBP4 SNPs with obesity, metabolic risk factors (blood pressure, triglycerides, high-density lipoprotein cholesterol, insulin resistance) and markers of vascular inflammation, such as high-sensitive C-reactive protein (hs-CRP), was tested. RESULTS: We found SNP rs3758538 to be associated with obesity (p = 0.007). Specifically, each copy of the minor allele C was associated with an increased risk of obesity, by more than twofold, in respect of being homozygous for the major allele A (odds ratio = 2.4; 95% confidence interval = 1.2-4.8). The rs3758538 and rs34571439 RBP4 SNPs correlated with plasma RBP4 levels. The SNPs rs12265684 and rs34571439 correlated with plasma triglyceride levels. The rs34571439 was also associated to hs-CRP levels. Marginal association of RBP4 SNPs with plasma high-density lipoprotein levels (rs34571439), blood pressure (rs12265684) and insulin resistance (rs3758539) was also observed. CONCLUSIONS: These findings suggest that childhood obesity may be associated with variations in RBP4 gene. The presence of selective SNPs in the RBP4 gene may account for metabolic complications.

Short Sleep Duration Is Related to Emerging Cardiovascular Risk Factors in Obese Children.

OBJECTIVE: The aim of the present study was to evaluate the influence of sleep duration on cardiovascular risk factors in obese children. METHODS: Cross-sectional analysis of 90 obese children ages 7 to 16 years. Anthropometric and clinical evaluation with specification of dietary and lifestyle habits was carried out during an office visit. Sleep duration was evaluated by the BEARS (B = bedtime issues, E = excessive daytime sleepiness, A = night awakening, R = regularity and duration of sleep, S = snoring) questionnaire on children's sleep characteristics. Sleep time adequacy by age was assessed according to the criteria of the National Sleep Foundation. Biochemical blood variables indicative of metabolic risk (glucose, lipid profile, and insulin) were obtained. Emergent new factors of metabolic risk, including high-sensitive C-reactive protein, γ-glutamyltranspeptidase, homocysteine, retinol-binding protein 4 (RBP4), thyroid-stimulating hormone (TSH), inflammatory markers, and the adipokines leptin, adiponectin, and ghrelin were also evaluated. The relations between the duration of sleep and these variables were analyzed by general lineal model analysis. Significant variables were introduced in logistic regression analysis to determine the odds ratio (OR) and 95% confidence interval (CI) of cardiometabolic factors with respect to sleep. RESULTS: Children who slept for short duration were significantly more at risk of severe central obesity. In the regression model, the mean arterial pressure (odds ratio [OR] 1.10, 95% confidence interval [CI] 1.02-1.17, P = 0.008), homocysteine (OR 1.41, 95% CI 1.08-1.84, P = 0.013), RBP4 (OR 1.78, 95% CI 1.15-2.78, P = 0.010), and TSH (OR 2.01, 95% CI 1.21-3.34, P = 0.007) remain as significant independent predictors related to short sleep duration. We did not find any association between sleep duration and inflammatory markers or adipokines. CONCLUSIONS: Short sleep duration increases the severity of obesity and is related to cardiovascular risk factors in children.