High leptin/adiponectin ratio and serum triglycerides are associated with an "at-risk" phenotype in young severely obese patients

Fat as a Friend or Foe of the Bone

PURPOSE OF REVIEW

The objective of this review is to summarize the literature on the prevalence and diagnosis of obesity and its metabolic profile, including bone metabolism, focusing on the main inflammatory and turnover bone mediators that better characterize metabolically healthy obesity phenotype, and to summarize the therapeutic interventions for obesity with their effects on bone health.

RECENT FINDINGS

Osteoporosis and fracture risk not only increase with age and menopause but also with metabolic diseases, such as diabetes mellitus. Thus, patients with high BMI may have a higher bone fragility and fracture risk. However, some obese individuals with healthy metabolic profiles seem to be less at risk of bone fracture. Obesity has become an alarming disease with growing prevalence and multiple metabolic comorbidities, resulting in a significant burden on healthcare and increased mortality. The imbalance between increased food ingestion and decreased energy expenditure leads to pathological adipose tissue distribution and function, with increased secretion of proinflammatory markers and harmful consequences for body tissues, including bone tissue. However, some obese individuals seem to have a healthy metabolic profile and may not develop cardiometabolic disease during their lives. This healthy metabolic profile also benefits bone turnover and is associated with lower fracture risk.

Ideal Cardiovascular Health and Adipokine Levels: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To evaluate the association between ideal cardiovascular health (CVH) and adipokine levels. Adipokines are hormones implicated in obesity and its cardiometabolic consequences. The concept of ideal CVH was introduced to promote 7 key health factors and behaviors in the general population. Previous studies have found strong associations between obesity and ideal CVH. However, existing literature on the link between CVH and adipokines is scarce.

METHODS

We studied 1842 Multi-Ethnic Study of Atherosclerosis participants free of cardiovascular disease who had 7 CVH metrics (smoking, body mass index, physical activity, diet, total cholesterol, blood pressure, and fasting blood glucose) measured at baseline and serum adipokine levels measured at a median of 2.4 years later. Each CVH metric was assigned a score of 0 (poor), 1 (intermediate), or 2 (ideal), and all scores were summed for a total CVH score (0-14). The total CVH scores of 0 to 8, 9 to 10, and 11 to 14 were considered inadequate, average, and optimal, respectively. We used multivariable linear regression models to assess the nonconcurrent associations between the CVH score and log-transformed adipokine levels.

RESULTS

The mean age was 62.1 ± 9.8 years; 50.2% of participants were men. After adjusting for sociodemographic factors, a 1-unit higher CVH score was significantly associated with 4% higher adiponectin and 15% and 1% lower leptin and resistin levels. Individuals with optimal CVH scores had 27% higher adiponectin and 56% lower leptin levels than those with inadequate CVH scores. Similar trends were observed for those with average versus inadequate CVH scores.

CONCLUSION

In a multi-ethnic cohort free of cardiovascular disease at baseline, individuals with average and optimal CVH scores had a more favorable adipokine profile than those with inadequate CVH scores.

Metabolically Healthy Obesity: Are Interventions Useful?

PURPOSE OF REVIEW

This review aims to detail the current global research state of metabolically healthy obesogenesis with regard to metabolic factors, disease prevalence, comparisons to unhealthy obesity, and targeted interventions to reverse or delay progression from metabolically healthy to unhealthy obesity.

RECENT FINDINGS

As a long-term condition with increased risk of cardiovascular, metabolic, and all-cause mortality risks, obesity threatens public health on a national level. The recent discovery of metabolically healthy obesity (MHO), a transitional condition during which obese persons carry comparatively lower health risks, has added to confusion about the true effect of visceral fat and subsequent long-term health risks. In this context, the evaluation of fat loss interventions, such as bariatric surgery, lifestyle changes (diet/exercise), and hormonal therapies require re-evaluation in light of evidence that progression to high-risk stages of obesity relies on metabolic status and that strategies to protect the metabolism may be useful in the prevention of metabolically unhealthy obesity. Typical calorie-based exercise and diet interventions have failed to reduce the prevalence of unhealthy obesity. Holistic lifestyle, psychological, hormonal, and pharmacological interventions for MHO, on the other hand, may at least prevent progression to metabolically unhealthy obesity.

Inheritance of perturbed methylation and metabolism caused by uterine malnutrition via oocytes

BACKGROUND

Undernourishment in utero has deleterious effects on the metabolism of offspring, but the mechanism of the transgenerational transmission of metabolic disorders is not well known. In the present study, we found that undernourishment in utero resulted in metabolic disorders of female F1 and F2 in mouse model.

RESULTS

Undernutrition in utero induced metabolic disorders of F1 females, which was transmitted to F2 females. The global methylation in oocytes of F1 exposed to undernutrition in utero was decreased compared with the control. KEGG analysis showed that genes with differential methylation regions (DMRs) in promoters were significantly enriched in metabolic pathways. The altered methylation of some DMRs in F1 oocytes located at the promoters of metabolic-related genes were partially observed in F2 tissues, and the expressions of these genes were also changed. Meanwhile, the abnormal DNA methylation of the validated DMRs in F1 oocytes was also observed in F2 oocytes.

CONCLUSIONS

These results indicate that DNA methylation may mediate the transgenerational inheritance of metabolic disorders induced by undernourishment in utero via female germline.

Serum Fatty Acid-Binding Protein 4 Levels in Adolescents: Effect of Insulin Resistance

Background: Fatty acid-binding protein 4 (FABP4) is an adipokine that plays a causative role in obesity and diabetes. In a stratified cross-sectional study with adolescents, we explored whether changes in FABP4 are already present in lean adolescents, provided they display elements of insulin resistance (IR). Methods: Adolescents were divided in four groups according to body mass index and homeostasis model assessment-IR. Results: In metabolically unhealthy lean (MUL) adolescents (MUL, lean with IR), FABP4 was 33% higher than in healthy counterparts (metabolically healthy lean [MHL]). Obese adolescents without IR (metabolically healthy obesity [MHO]) had 50% higher levels of FABP4 than their lean counterparts (MHL), while levels of FABP4 in obese adolescents with IR (metabolically unhealthy obese [MUO]) were 220% higher than those of MUL adolescents. The differences were significant at least with P < 0.005. MUO > MHO > MUL. Our data demonstrate that the known FABP4 defect in adults with obesity also occurs in youth and even in lean adolescents, suggesting an early association between impaired glucose metabolism and FABP4 irrespective of body weight. FABP4 was more sensitive in discerning each of our 4 subgroups than either adiponectin or leptin. Moreover, evidence for a putative early adiponectin resistance in MUL suggests a combined defect in these adolescents that call for early detection and prevention of the metabolic disturbance that should stay away from concentrating only in subjects with obesity. Conclusions: Our data may serve to draw the considerable attention that is currently paid to FABP4 to the adolescent population, irrespective of the presence of obesity. Further studies with larger cohorts and analyses of visceral and liver fat are warranted.

Adipsin Serum Concentrations and Adipose Tissue Expression in People with Obesity and Type 2 Diabetes

(1) Adipsin is an adipokine that may link increased fat mass and adipose tissue dysfunction to obesity-related cardiometabolic diseases. Here, we investigated whether adipsin serum concentrations and adipose tissue (AT) adipsin mRNA expression are related to parameters of AT function, obesity and type 2 diabetes (T2D). (2) Methods: A cohort of 637 individuals with a wide range of age and body weight (Age: 18–85 years; BMI: 19–70 kg/m2) with (n = 237) or without (n = 400) T2D was analyzed for serum adipsin concentrations by ELISA and visceral (VAT) and subcutaneous (SAT) adipsin mRNA expression by RT-PCR. (3) Results: Adipsin serum concentrations were significantly higher in patients with T2D compared to normoglycemic individuals. We found significant positive univariate relationships of adipsin serum concentrations with age (r = 0.282, p < 0.001), body weight (r = 0.264, p < 0.001), fasting plasma glucose (r = 0.136, p = 0.006) and leptin serum concentrations (r = 0.362, p < 0.001). Neither VAT nor SAT adipsin mRNA expression correlated with adipsin serum concentrations after adjusting for age, sex and BMI. Independent of T2D status, we found significantly higher adipsin expression in SAT compared to VAT (4) Conclusions: Our data suggest that adipsin serum concentrations are strongly related to obesity and age. However, neither circulating adipsin nor adipsin AT expression reflects parameters of impaired glucose or lipid metabolism in patients with obesity with or without T2D.

Metagenome-Scale Metabolic Network Suggests Folate Produced by Bifidobacterium longum Might Contribute to High-Fiber-Diet-Induced Weight Loss in a Prader-Willi Syndrome Child

Gut-microbiota-targeted nutrition intervention has achieved success in the management of obesity, but its underlying mechanism still needs extended exploration. An obese Prader-Willi syndrome boy lost 25.8 kg after receiving a high-fiber dietary intervention for 105 days. The fecal microbiome sequencing data taken from the boy on intervention days 0, 15, 30, 45, 60, 75, and 105, along with clinical indexes, were used to construct a metagenome-scale metabolic network. Firstly, the abundances of the microbial strains were obtained by mapping the sequencing reads onto the assembly of gut organisms through use of reconstruction and analysis (AGORA) genomes. The nutritional components of the diet were obtained through the Virtual Metabolic Human database. Then, a community model was simulated using the Microbiome Modeling Toolbox. Finally, the significant Spearman correlations among the metabolites and the clinical indexes were screened and the strains that were producing these metabolites were identified. The high-fiber diet reduced the overall amount of metabolite secretions, but the secretions of folic acid derivatives by Bifidobacterium longum strains were increased and were significantly relevant to the observed weight loss. Reduced metabolites might also have directly contributed to the weight loss or indirectly contribute by enhancing leptin and decreasing adiponectin. Metagenome-scale metabolic network technology provides a cost-efficient solution for screening the functional microbial strains and metabolic pathways that are responding to nutrition therapy.

Children with metabolically healthy obesity have a worse metabolic profile compared to normal-weight peers: a cross-sectional study

PURPOSE

A phenotype of metabolically healthy obesity (MHO) has been described in youth with obesity, but data are still scarce in this age group. The aim of the current study was to describe and compare clinical and laboratory parameters related to obesity among three different groups of youth, namely youth with normal weight (NW), with MHO, and with metabolically unhealthy obesity (MUO).

METHODS

One hundred and three youngsters with obesity were divided according to 2018 consensus-based criteria into those with MHO [n = 49, age (±SD): 10.9 ± 2.9 years] and those with MUO [n = 54, 11.5 ± 2.7 years] and were compared to age-, sex- and Tanner-matched NW [n = 69, 11.3 ± 2.9 years]. Several obesity-related parameters were investigated for all three groups of children. Comparisons were made by analysis of variance (ANOVA) followed by the Fisher's PLSD test.

RESULTS

Youth with MHO had lower systolic (p < 0.001) and diastolic (p < 0.01) blood pressure z-score and triglycerides (p < 0.01), but higher HDL-C (p < 0.001), total cholesterol (p < 0.05), and apo-A1 (p < 0.05) compared to those with MUO. Compared to controls, both children with MHO and MUO showed higher fasting insulin (p < 0.05), HOMA-IR (p < 0.05), and QUICKI (p < 0.001). Similarly, both groups had higher hsCRP, fibrinogen, uric acid, and leptin compared to controls (for all, p < 0.001), while their adiponectin was lower (p < 0.05). Visfatin was higher in children with MUO compared to controls (p < 0.01), and it showed a trend to be lower in children with MHO compared to those with MUO (p = 0.1).

CONCLUSION

This study provides evidence that children identified as having MHO by the consensus-based criteria had better metabolic profiles than youth with MUO, but worse than NW. Further research is needed in pediatric populations both regarding MHO criteria and the nature of the MHO phenotype per se.

Effects of obesity and 10 weeks metformin treatment on liver steatosis

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver disease in adolescents and adults, and the risk of developing NAFLD increases with obesity. In the present study, it was shown that obesity increased fatty liver (steatosis) using an obese Zucker rat model. Metformin is an oral anti-hyperglycemic agent approved by the FDA for treatment of type 2 diabetes in adults and children >10 years of age. There is insufficient evidence regarding the effects of metformin on pediatric liver steatosis. Thus, in the present study, the effects of 10 weeks metformin treatment on liver steatosis and related serum markers for liver damage was assessed. Lean and obese (n=16 per group) 5-week old female Zucker rats were provided an AIN-93 G diet for 8 weeks to induce NAFLD, and then rats were randomly assigned to 4 groups (8 rats/group): i) lean without metformin (LC), ii) lean + metformin (LM), iii) obese without metformin (OC), and iv) obese + metformin (OM). Rats were provided ad libitum access to the diet containing metformin (1 g metformin per kg of food). Rats were weighed twice weekly and were sacrificed 10 weeks later. Serum was collected to measure the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), leptin and adiponectin. Livers were collected for histological analysis. The results showed that obese rats gained significantly more weight than lean rats in both the control and metformin treatment groups (P<0.001). OM treated rats exhibited a lower degree of liver steatosis compared with the OC rats (P<0.04). There were no significant differences in serum ALT levels between the groups. However, obesity significantly increased serum AST levels in both the control and metformin treatment groups (P=0.01). The ratio of leptin to adiponectin was increased in obese compared with the lean rats in both the control and metformin treatment groups (P<0.0001). There was no effect of metformin on serum biomarkers. In summary, short-term metformin treatment decreased liver steatosis but did not affect the serum markers of liver steatosis.

Bariatric surgery decreases oxidative stress and protein glycosylation in patients with morbid obesity

BACKGROUND

There is growing evidence that oxidative stress (OS) is a critical factor linking obesity with its associated comorbidities, such as cardiovascular diseases.

AIM

To evaluate the degree of OS in people with morbid obesity and its relationship with glycoproteins, determined using 1H-NMR spectroscopy, before and after bariatric surgery (BS).

METHODS

In this observational cohort study, plasma from 24 patients with BMI ≥ 40 kg/m² (age: 21-65 years) was used to measure metabolites implicated in OS. We measured glycoprotein (GlycA, GlycB and GlycF) areas and shape factors (H/W = height/width).

RESULTS

One year after BS, oxidized low-density lipoprotein had decreased by 49% (P < .0001), malondialdehyde by 32% (P = .0019) and lipoprotein (a) by 21% (P = .0039). The antioxidant enzymes paraoxonase-1 and catalase increased after BS (43%, P < .0001 and 54%, P = .0002, respectively). Superoxide dismutase-2 had fallen 1 year after BS (32%, P = .0052). After BS, both the glycoprotein areas and shape factors decreased by 20%-26%. These glycoproteins were significantly correlated with OS parameters. The plasma atherogenic index was 63% higher in obese individuals than 1 year after BS and correlated positively with glycoproteins.

CONCLUSION

For the first time, we here demonstrate the relationship between OS parameters and glycoproteins in people with morbid obesity. So glycoproteins could therefore be a good indicator, together with the oxidative state to assess patient prognosis after BS.

Serum miR-503 is a Candidate Biomarker for Differentiating Metabolic Healthy Obesity from Metabolic Unhealthy Obesity

PURPOSE

Overweight and obesity are associated with metabolic diseases. However, a subgroup of the overweight/obese population does not present metabolic abnormalities. Hence, there is an urgent need to identify biomarkers that can distinguish different obesity phenotypes and metabolic status.

PATIENTS AND METHODS

A total of 98 individuals were divided into three groups: metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). Participants were evaluated for anthropometric and biochemical parameters and serum BMPR1A concentration and miR-503 level. Receiver operating characteristic (ROC) curve analysis and logistic regression analysis were performed.

RESULTS

The level of miR-503 was significantly higher in the MHO group compared with that in the MUO group, but no difference was observed between the MHNW and MHO groups. Meanwhile, no significant differences in serum BMPR1A concentration were observed between the three groups. ROC curve analysis showed that miR-503 could be used as a marker to distinguish the MUO from the MHO. Logistic regression analysis suggested that miR-503 was an important related factor associated with an unhealthy metabolic state in overweight/obese subjects.

CONCLUSION

miR-503 can be considered as a suitable biomarker to distinguish between the MUO and MHO, which may be a related factor for the incidence of metabolic disorders in overweight/obese subjects.

Circulating Osteonectin and Adipokine Profiles in Relation to Metabolically Healthy Obesity in Chinese Children: Findings From BCAMS

Background The role of adipokine dysregulation in determining the metabolic fate of obesity is not well studied. We aimed to examine whether the matricellular protein osteonectin and the profiles of certain adipokines could differentiate metabolically healthy obese ( MHO ) versus metabolically unhealthy obese phenotypes in childhood. Methods and Results This study included 1137 obese children and 982 normal-weight healthy ( NWH ) controls recruited from the BCAMS (Beijing Child and Adolescent Metabolic Syndrome) study. MHO was defined by the absence of insulin resistance and/or any metabolic syndrome components. Six adipokines-osteonectin, leptin, adiponectin, resistin, FGF21 (fibroblast growth factor 21), and RBP-4 (retinol binding protein 4)-were assessed. Approximately 20% of obese children displayed the MHO phenotype. MHO children had a more favorable adipokine profile than metabolically unhealthy obese children, with lower osteonectin, leptin, and RBP -4 and higher adiponectin (all P<0.05). Compared with normal-weight healthy controls, MHO children displayed increased leptin, resistin, and RBP -4 levels and reduced adiponectin concentrations (all P<0.05) but similar osteonectin and FGF 21 levels. Among obese subjects, decreased osteonectin (odds ratio [OR]: 0.82; 95% confidence interval [CI] per standard deviation, 0.70-0.97), RBP -4 (OR: 0.77; 95% CI per standard deviation, 0.64-0.93), and leptin/adiponectin ratio (OR: 0.58; 95% CI per standard deviation, 0.43-0.77) were independent predictors of MHO . In addition, compared with children without abnormalities, those with any 3 adipokine abnormalities were 80% less likely to exhibit the MHO phenotype ( OR : 0.20; 95% CI , 0.10-0.43) and 3 times more likely to have metabolic syndrome ( OR : 2.77; 95% CI , 1.52-5.03). Conclusions These findings suggest that dysregulation of adipokines might govern the metabolic consequences of obesity in children. Low osteonectin levels, along with a healthy adipokine profile, might be used as an early marker of the MHO phenotype.

MC4R Single Nucleotide Polymorphisms Were Associated with Metabolically Healthy and Unhealthy Obesity in Chinese Northern Han Populations

Melanocortin-4 receptor (MC4R) has been reported to be associated with the risk of obesity, and metabolically unhealthy obese (MUHO) patients tend to have a greater risk of cardiovascular complications than metabolically healthy obese (MHO) patients. Therefore, we aimed to study single nucleotide polymorphisms (SNPs) in the MC4R gene associated with metabolically healthy and unhealthy obesity in Chinese Northern Han populations. A total of 1100 Chinese Northern Han subjects were recruited and divided into four groups according to the criteria of the Adult Treatment Panel-III (ATP-III) and World Health Organization (WHO): MUHO (n = 300), MHO (n = 196), metabolic unhealthy normal weight (MUH-NW) (n = 303), and metabolic healthy normal weight (MH-NW) (n = 301). DNA samples were extracted, and six SNPs of the MC4R gene, including rs2331841, rs656710, rs17782313, rs571312, rs12970134, and rs11872992, were genotyped with the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method. Among the six SNPs of the MC4R gene, rs2331841 (A/G) was the most significant and could account for 0.9% of obesity etiology. Compared with the normal weight group, rs2331841 of the MC4R gene was associated with obesity (P=0.032). The obesity risk of subjects with the AG genotype in the rs2331841 site was 82% higher than the risk of those with the GG genotype (β = 0.60, OR = 1.82, P=0.030). After adjusting for sex and age, the frequency of the A allele in the rs2331841 site was higher in the MUHO group than in the MH-NW group (27.9% vs. 21.1%, respectively, OR = 1.49, 95% CI 1.14-1.96, P=0.005) and in the MUHO group than in the MHO group (27.9% vs. 22.3%, respectively, OR = 1.39, 95% CI 1.02-1.92, P=0.039). Among the three genotypes of rs2331841, the subjects with the AA/AG genotype had higher diastolic blood pressure (DBP) than those with the GG genotype. Our data first suggest that SNPs in the rs2331841 site of the MC4R gene are closely related to obesity and its related metabolic disorders in Chinese Northern Han populations. The participants with an A allele of rs2331841 had a higher risk of obesity and MUHO than other participants.

Leptin/adiponectin ratio in overweight patients - gender differences

OBJECTIVE

Obesity-related atherosclerosis is a systemic disease with a background connected to multiple metabolic-neurohumoral pathways. The leptin/adiponectin ratio has been suggested as an atherosclerotic marker in obese patients. The aim of this study was to assess (1) the significance of the L/A ratio in overweight subjects, (2) the relation with anthropometric/metabolic parameters and (3) gender difference.

METHOD

The study included 80 adult males and females, overweight, non-diabetic patients. Biochemical blood analysis and anthropometric and cardiovascular measurements were performed. Serum leptin levels were measured with a radioimmunoassay test and total adiponectin levels with enzyme-linked immunosorbent assay. Leptin/adiponectin ratios were calculated as ratios between total serum concentrations of leptin and adiponectin.

RESULTS

Differences between leptin, adiponectin serum levels and leptin/adiponectin ratios are presented in overweight persons, where females have a significantly higher leptin/adiponectin ratio than men ( p < 0.001). In men, the leptin/adiponectin ratio showed a positive correlation with total cholesterol levels ( p = 0.011), low-density lipoprotein ( p = 0.013) and triglycerides ( p = 0.032). In females, the leptin/adiponectin ratio correlated with anthropometric parameters of visceral obesity: waist circumference ( p = 0.001) and waist-to-hip ratio ( p = 0.025).

CONCLUSION

The leptin/adiponectin ratio could represent an atherosclerotic risk marker of the early stage of obesity. Gender plays a significant role in pathophysiological changes, with different clinical manifestations, where sex hormones have a crucial effect on neurohumoral adipose tissue activity.

Relationship of Circulating Fetuin-A Levels with Body Size and Metabolic Phenotypes

BACKGROUND

Previous studies have suggested the existence of distinct body size subgroups according to metabolic health referred to as metabolically healthy obesity (MHO) and metabolically abnormal but normal weight (MANW) patients. Although nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity and metabolic syndrome, the relationship between these phenotypes and fetuin-A, a representative hepatokine, has not been explored.

METHODS

We examined the association between circulating fetuin-A levels, metabolic health phenotypes, cardiometabolic risk parameters, and subclinical atherosclerosis in 290 subjects who were randomly selected from an ongoing cohort study.

RESULTS

Fetuin-A concentrations were significantly associated with detrimental anthropometric and laboratory measurements, including increased waist circumference, blood pressure, alanine aminotransferase, fasting plasma glucose, and triglyceride levels. Furthermore, fetuin-A levels were significantly increased in the metabolically abnormal (MA) group compared to the metabolically healthy (MH) group in subjects without obesity (717.1 [632.1, 769.7] vs. 599.5 [502.0, 709.3], P = 0.001) and subjects with obesity (704.1 [595.5-880.9] vs. 612.2 [547.9-802.1], P = 0.016). In addition, brachial-ankle pulse wave velocity (baPWV), which reflects arterial stiffness, was higher in MA individuals compared to MH individuals. Multiple logistic regression analysis revealed that both individuals without obesity (P for trend = 0.017) and with obesity (P for trend = 0.028) in the higher tertiles of fetuin-A had an increased risk of MA than those in the lowest tertile.

CONCLUSIONS

This study demonstrates that fetuin-A levels are significantly associated with metabolic health phenotypes, such as MHO and MANW, in Korean adults.

Adipokines are Associated With Hypertension in Metabolically Healthy Obese (MHO) Children and Adolescents: A Prospective Population-Based Cohort Study

Background

The potential mechanism underlying the relationship between the risk of cardiovascular diseases and metabolically healthy obese (MHO) individuals remains unclear. The aim of the study was to prospectively investigate the potential role of the adipokines in the association between the MHO phenotype and hypertension in children and adolescents.

Methods

A total of 1184 participants at baseline were recruited from a cohort of the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) study. The participants were classified according to their body mass index (BMI) and metabolic syndrome (MS) components. The levels of the adipokines, including leptin, adiponectin, and resistin, were measured.

Results

MHO individuals had higher leptin levels (11.58 ug/L vs 1.20 ug/L), leptin/adiponectin ratio (1.18 vs 0.07), and lower adiponectin (11.65 ug/L vs 15.64 ug/L) levels compared to metabolically healthy normal-weight individuals (all P < 0.05). Compared to metabolically healthy normal-weight individuals, the prevalence of high leptin levels (26.5% vs 0.4%), low adiponectin levels (17.9% vs 6.3%) and a high leptin/adiponectin ratio (26.0% vs 2.1%) was higher in MHO individuals (all P < 0.01). The MHO individuals with abnormal adipokines were significantly more likely to developing hypertension (high leptin, relative risk 11.04; 95% confidence interval, 1.18–103.35; and high leptin/adiponectin ratio, relative risk 9.88; 95% confidence interval, 1.11–87.97) compared to metabolically healthy normal-weight individuals with normal adipokine levels.

Conclusions

The abnormal adipokine levels contribute to the increased hypertension risk in MHO children and adolescents. The non-traditional risk factors should be highlighted in MHO children and adolescents in clinical practice and research.

Long-Term Sex-Dependent Vulnerability to Metabolic challenges in Prenatally Stressed Rats

Prenatal stress (PNS) might affect the developmental programming of adult chronic diseases such as metabolic and mood disorders. The molecular mechanisms underlying such regulations may rely upon long-term changes in stress-responsive effectors such as Brain-Derived Neurotrophic Factor (BDNF) that can affect neuronal plasticity underlying mood disorders and may also play a role in metabolic regulation. Based upon previous data, we hypothesized that PNS might lead to greater vulnerability to an obesogenic challenge experienced at adulthood. In order to investigate our hypothesis, pregnant Sprague-Dawley female rats underwent a chronic procedure of restraint stress during the last week of gestation. The adult offspring were then challenged with a high fat diet (HFD) over 8 weeks and tested for metabolic and emotional endpoints. Moreover, brain specific changes in Bdnf expression levels were also assessed. Overall, HFD resulted in increased caloric intake, insulin resistance, impaired glucose tolerance and higher circulating levels of leptin, while PNS increased the leptin/adiponectin ratio, an index of metabolic risk in adult male subjects. Interestingly, HFD consumption increased anxiety-like behaviors in the Elevated Plus Maze, particularly in males, and this effect was buffered by PNS. Levels of Bdnf were finely modulated by PNS and HFD in a region- and sex-dependent fashion: female offspring overall showed greater plasticity, possibly mediated through increased total Bdnf mRNA expression both in the hippocampus and in the hypothalamus. In conclusion, while the experience of maternal stress during intrauterine life promotes metabolic dysfunction induced by a HFD at adulthood, the interaction between PNS and HFD is positive in male subjects, and in agreement with the match-mismatch hypothesis, resulting in a reduction of anxious behaviors.

Gamma-glutamyltransferase activity as a surrogate biomarker of metabolic health status in young nondiabetic obese women

Aim: We investigated the association of gamma-glutamyltransferase (GGT) activity with atherogenic risk factors and metabolic health status in young nondiabetic obese women. Methods & results: In 140 obese women GGT activity was independently associated with BMI, triglyceride to high-density cholesterol ratio and homeostasis model assessment. Metabolically healthy but obese women had significantly lower GGT activity, associated with a normal insulin sensitivity, favorable lipid profile and apolipoprotein B to apolipoprotein AI ratio. GGT activity showed good diagnostic accuracy to distinguish between metabolically healthy but obese and obese women at risk (77.8% sensitivity and 60% specificity). GGT activity >17 U/l can predict atherogenic risk and insulin resistance. Conclusion: GGT activity may serve as a potential surrogate biomarker of atherogenic risk and metabolic health status.

Genomic Microdiversity of Bifidobacterium pseudocatenulatum Underlying Differential Strain-Level Responses to Dietary Carbohydrate Intervention

The genomic basis of the response to dietary intervention of human gut beneficial bacteria remains elusive, which hinders precise manipulation of the microbiota for human health. After receiving a dietary intervention enriched with nondigestible carbohydrates for 105 days, a genetically obese child with Prader-Willi syndrome lost 18.4% of his body weight and showed significant improvement in his bioclinical parameters. We obtained five isolates (C1, C15, C55, C62, and C95) of one of the most abundantly promoted beneficial species, Bifidobacterium pseudocatenulatum, from a postintervention fecal sample. Intriguingly, these five B. pseudocatenulatum strains showed differential responses during the dietary intervention. Two strains were largely unaffected, while the other three were promoted to different extents by the changes in dietary carbohydrate resources. The differential responses of these strains were consistent with their functional clustering based on the COGs (Clusters of Orthologous Groups), including those involved with the ABC-type sugar transport systems, suggesting that the strain-specific genomic variations may have contributed to the niche adaption. Particularly, B. pseudocatenulatum C15, which had the most diverse types and highest gene copy numbers of carbohydrate-active enzymes targeting plant polysaccharides, had the highest abundance after the dietary intervention. These studies show the importance of understanding genomic diversity of specific members of the gut microbiota if precise nutrition approaches are to be realized.

The manipulation of the gut microbiota via dietary approaches is a promising option for improving human health. Our findings showed differential responses of multiple B. pseudocatenulatum strains isolated from the same habitat to the dietary intervention, as well as strain-specific correlations with bioclinical parameters of the host. The comparative genomics revealed a genome-level microdiversity of related functional genes, which may have contributed to these differences. These results highlight the necessity of understanding strain-level differences if precise manipulation of gut microbiota through dietary approaches is to be realized.

Insulin sensitivity and its relation to hormones in adolescent boys and girls

BACKGROUND AND AIMS

A subset of obese individuals lacks cardiometabolic impairment. We aimed to analyze hormonal profiles of insulin-sensitive obese (ISO) and insulin-resistant obese (IRO) adolescents and determine hormonal predictors of homeostasis model of insulin resistance (HOMA-IR).

MATERIALS AND METHODS

A threshold of 3.16 of HOMA-IR was used to classify ISO (<3.16) IRO (≥3.16). In 702 individuals aged 13-18years (55.8% girls) anthropometric and laboratory [blood glucose, insulin, thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), sex hormone-binding globulin (SHBG), steroid hormones, luteinizing hormone, follicle stimulating hormone, prolactin, ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like-peptide 1glucagon, leptin, resistin, visfatin, leptin, adiponectin and adipsin] assessments were performed. Orthogonal projections to latent structures and Mann-Whitney tests with Bonferroni correction were applied for statistical analysis.

RESULTS

52.6% girls and 42.9% boys were insulin sensitive. In the predictive model of HOMA-IR thyroid function tests, adiponectin, ghrelin and leptin concentrations played an important role in both genders. Prolactin, testosterone and glucagon contributed to the model only in boys, while progesterone and dehydroepiandrosterone sulfate levels only in girls. After Bonferroni correction levels of leptin, adiponectin, leptin/adiponectin ratio, SHBG and fT4/TSH ratio in both genders, testosterone and glucagon levels in boys and levels of TSH and fT3 in girls were related to insulin sensitivity.

CONCLUSION

Metabolic health defined by HOMA-IR is partly predicted by various hormones. Some of them are gender specific. Free T4/TSH and leptin/adiponectin ratios are related to insulin sensitivity in both genders.

Diet-Induced Obesity and the Mechanism of Leptin Resistance

Leptin signaling blockade by chronic overstimulation of the leptin receptor or hypothalamic pro-inflammatory responses due to elevated levels of saturated fatty acid can induce leptin resistance by activating negative feedback pathways. Although, long form leptin receptor (Ob-Rb) initiates leptin signaling through more than seven different signal transduction pathways, excessive suppressor of cytokine signaling-3 (SOCS-3) activity is a potential mechanism for the leptin resistance that characterizes human obesity. Because the leptin-responsive metabolic pathways broadly integrate with other neurons to control energy balance, the methods used to counteract the leptin resistance has extremely limited effect. In this chapter, besides the impairment of central and peripheral leptin signaling pathways, limited access of leptin to central nervous system (CNS) through blood-brain barrier, mismatch between high leptin and the amount of leptin receptor expression, contradictory effects of cellular and circulating molecules on leptin signaling, the connection between leptin signaling and endoplasmic reticulum (ER) stress and self-regulation of leptin signaling has been discussed in terms of leptin resistance.

Adiponectin-Resistance in Obesity

The decrease in adiponectin levels are negatively correlated with chronic subclinical inflammation markers in obesity. The hypertrophic adipocytes cause obesity-linked insulin resistance and metabolic syndrome. Furthermore, macrophage polarization is a key determinant regulating adiponectin receptor (AdipoR1/R2) expression and differential adiponectin-mediated macrophage inflammatory responses in obese individuals. In addition to decrease in adiponectin concentrations, the decline in AdipoR1/R2 mRNA expression leads to a decrement in adiponectin binding to cell membrane, and this turns into attenuation in the adiponectin effects. Within the receptor complex, adaptor protein-containing pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif 1 (APPL1) is the intracellular binding partner of AdipoR1 and AdipoR2. The expression levels of APPL1 or APPL2 lead to an altered adiponectin activity. Despite normal or high adiponectin levels, an impaired post receptor signaling due to APPL1/APPL2 may alter adiponectin efficiency and activity. However, APPL2 blocks adiponectin signaling through AdipoR1 and AdipoR2 by competitive inhibition of APPL1. APPL1 is also an important mediator of adiponectin dependent insulin sensitization. In this context, adiponectin resistance is associated with insulin resistance and is thought to be partly due to the down-regulation of the AdipoRs in high-fat diet fed subjects. Actually, adiponectin resistance occurs very rapidly after saturated fatty acid feeding, this metabolic disturbance is not due to a decrease in AdipoR1 protein content. Intra-abdominal adipose tissue-AdipoR2 expression is reduced in obesity, whereas AdipoR1 expression is not changed. Adiponectin resistance together with insulin resistance forms a vicious cycle. The elevated adiponectin levels with adiponectin resistance is a compensatory response in the condition of an unusual discordance between insulin resistance and adiponectin unresponsiveness.Additionally, different mechanisms are involved in vascular adiponectin resistance at different stages of obesity. Nevertheless, diet-induced hyperlipidemia is the leading cause of vascular adiponectin resistance. Leptin/adiponectin imbalance may also be an important marker of the elevated risk of developing abdominal obesity-associated cardiovascular diseases.

Leptin as a cardiovascular risk marker in metabolically healthy obese: Hyperleptinemia in metabolically healthy obese

Adipokines contribute to the inflammatory process which can lead to obesity-associated cardiometabolic complications. Metabolically healthy obese individuals seem to be protected or more resistant to develop these complications and it is intriguing why some individuals develop comorbidities and others do not. Thus, we questioned whether the differences between metabolically healthy and unhealthy obese relied on the alterations in metabolic profile, characterized by serum leptin and adiponectin. A total of 142 obese adults were divided into 2 groups - metabolically healthy obese (MHO) or unhealthy obese (MUO) - and they were evaluated for anthropometric measures, body composition, blood pressure, dietary intakes and plasma levels of leptin and adiponectin. Leptin/adiponectin ratio (L/A) was calculated. Age, BMI and blood pressure were higher in the MUO. No differences in anthropometric measurements, body composition, dietary intake and dietary quality were observed between groups. Leptin were significantly higher in the MUO (53.07 ± 34.56 versus 36.27 ± 24.02 ng/ml in the MHO, r < 0.04). The logistic regression analysis demonstrated that leptin was an important factor associated with not being healthy, independent of age, body weight and BMI. There were no differences between groups for adiponectin and L/A. Leptin correlated positively with body weight (r = 0.25, r < 0.05), BMI (r = 0.38, r < 0.05) and BF (r = 0.74, r < 0.05), and negatively with FFM (r = -0.74, r < 0.05). Our findings suggest that leptin is an important cardiovascular disease marker to obese population and can contribute to evaluate metabolic risks in these individuals.

Molecular Neurobiology and Promising New Treatment in Depression

The limited effects of currently available antidepressants are becoming an urgent issue in depression research. It takes a long time to determine treatment effects, and the overall remission rate is low. Although we expect the development of non-monoamine antidepressants in the near future, efforts in this regard over the past several decades have not yet been compensated. Thus, researchers and clinicians should clarify the neurobiological mechanisms of integrated modulators that regulate changes in genes, cells, the brain, and behaviors associated with depression. In this study, we review molecular neurobiological theories and new treatments for depression. Beyond neuroanatomy and monoamine theory, we discuss cells and molecules, neural plasticity, neurotrophisms, endocrine mechanisms, immunological mechanisms, genetics, circadian rhythms, and metabolic regulation in depression. In addition, we introduce the possibility of new antidepressant drug development using protein translation signaling (mTOR) pathways.

Prediction of Cardiorespiratory Fitness by the Six-Minute Step Test and Its Association with Muscle Strength and Power in Sedentary Obese and Lean Young Women: A Cross-Sectional Study

Impaired cardiorespiratory fitness (CRF) is a hallmark characteristic in obese and lean sedentary young women. Peak oxygen consumption (VO_2peak) prediction from the six-minute step test (6MST) has not been established for sedentary females. It is recognized that lower-limb muscle strength and power play a key role during functional activities. The aim of this study was to investigate cardiorespiratory responses during the 6MST and CPX and to develop a predictive equation to estimate VO_2peak in both lean and obese subjects. Additionally we aim to investigate how muscle function impacts functional performance. Lean (LN = 13) and obese (OB = 18) women, aged 20–45, underwent a CPX, two 6MSTs, and isokinetic and isometric knee extensor strength and power evaluations. Regression analysis assessed the ability to predict VO_2peak from the 6MST, age and body mass index (BMI). CPX and 6MST main outcomes were compared between LN and OB and correlated with strength and power variables. CRF, functional capacity, and muscle strength and power were lower in the OB compared to LN (<0.05). During the 6MST, LN and OB reached ~90% of predicted maximal heart rate and ~80% of the VO_2peak obtained during CPX. BMI, age and number of step cycles (NSC) explained 83% of the total variance in VO_2peak. Moderate to strong correlations between VO_2peak at CPX and VO_2peak at 6MST (r = 0.86), VO_2peak at CPX and NSC (r = 0.80), as well as between VO_2peak, NSC and muscle strength and power variables were found (p<0.05). These findings indicate the 6MST, BMI and age accurately predict VO_2peak in both lean and obese young sedentary women. Muscle strength and power were related to measures of aerobic and functional performance.

Laparoscopic adjustable gastric banding reduces subcutaneous adipose tissue and blood inflammation in nondiabetic morbidly obese individuals

BACKGROUND

Significant and sustained excess weight loss (EWL) appears to reduce the risk of obesity-related comorbidities (insulin resistance, hyperlipidemia, and inflammation), but this has been primarily shown in adult diabetic obese patients. We evaluated whether the EWL obtained 3 years after laparoscopic adjustable gastric banding (LAGB) improves the metabolic phenotype in nondiabetic morbidly obese (NDMO) individuals from south Italy.

METHODS

Serum and subcutaneous adipose tissue (SAT) samples from 20 obese individuals (median BMI=41.5 kg/m(2)) before (T0) and after LAGB (T1) and from 10 controls (median BMI=22.8 kg/m(2)) were taken. Serum leptin, adiponectin, C reactive protein (CRP), and main analyte levels were evaluated by routine methods or immunoassay. In SAT, adipocyte size was measured by hematoxylin/eosin staining, cluster of differentiation 68 (CD68) macrophage infiltration marker by immunohistochemistry, and adiponectin, adiponectin receptors 1 and 2, and interleukin 6 (IL6) messenger RNAs by qRT-PCR.

RESULTS

The average EWL was 66.7 %, and CRP, triglycerides, hepatic markers, leptin levels, homeostasis model assessment, and the leptin/adiponectin ratio were lower (p<0.05) at T1 than at T0. The expression of small adipocytes and adiponectin was increased (p<0.05), and inflammation markers (CD68 and IL6) decreased (p<0.05) at T1 vs. T0. At linear regression multivariate analysis, over 90 % (R (2)=0.905) of EWL (dependent variable) was explained by CD68, adiponectinemia, triglyceridemia, CRP, and total protein levels.

CONCLUSIONS

The EWL obtained 3 years after LAGB resulted in an improvement of lipid metabolism and a reduction of inflammation in NDMO patients, thereby decreasing the risk of obesity-associated diseases.

Differential effects of leptin on adiponectin expression with weight gain versus obesity

Background/Objective

Adiponectin exerts beneficial effects by reducing inflammation, and improving lipid metabolism and insulin-sensitivity. Although adiponectin is lower in obese individuals, whether weight gain reduces adiponectin expression in humans is controversial. We sought to investigate the role of weight gain, and consequent changes in leptin, on altering adiponectin expression in humans.

Methods/Results

Forty four normal-weight healthy subjects were recruited (mean age 29 years; 14 women) and randomized to either gain 5% of body weight by 8-weeks of overfeeding (n=34) or maintain weight (n=10). Modest weight gain of 3.8 ± 1.2 kg resulted in increased adiponectin (p=0.03) while weight maintenance resulted in no changes in adiponectin. Further, changes in adiponectin correlated positively with changes in leptin (p=0.0085). In-vitro experiments using differentiated human white preadipocytes showed that leptin increased adiponectin mRNA and protein expression, while a leptin-antagonist had opposite effects. To understand the role of leptin in established obesity, we compared adipose tissue samples obtained from normal weight versus obese subjects. We noted, first, that leptin activated cellular signaling pathways and increased adiponectin mRNA in adipose tissue from normal-weight participants, but did not do so in adipose tissue from obese participants; and second, that obese subjects had increased caveolin-1 expression, which attenuates leptin-dependent increases in adiponectin.

Conclusions

Modest weight gain in healthy individuals is associated with increases in adiponectin, which correlate positively with changes in leptin. In-vitro, leptin induces adiponectin expression which is attenuated by increased caveolin-1 expression. Additionally, adipose tissue from obese subjects shows increased caveolin-1 expression, and impaired leptin signaling. This leptin signal impairment may prevent concordant increases in adiponectin in obese subjects despite their high levels of leptin. Therefore, impaired leptin signaling may contribute to low adiponectin expression in obesity and may provide a target for increasing adiponectin expression, hence improving insulin sensitivity and cardio-metabolic profile in obesity.

Metabolically healthy obese individuals: Key protective factors

OBJECTIVES

Obesity is a significant quality of life-impairing health problem affecting industrialized nations. However, despite carrying a large fat mass, some very obese individuals exhibit normal metabolic profiles (metabolically healthy obesity). The physiological factors underlying their protective and favorable metabolic profiles remain poorly defined.

METHODS

A search of the National Library of Medicine PubMed database was performed using the following keywords: Metabolically healthy obese, metabolically normal obese, insulin resistance, metabolically unhealthy normal weight, and uncomplicated obesity.

RESULTS

This article reviewed factors associated with severe obesity that lacks complications, and suggests putative activities by which these obese individuals avoid developing the clinical features of metabolic syndrome, or the metabolic complications associated with severe obesity.

CONCLUSIONS

Despite the knowledge that visceral fat deposition is the seminal factor that ultimately causes insulin resistance (IR) and the detrimental inflammatory and hormonal profile that contributes to increase risk for cardiovascular disease, it remains unknown whether metabolically healthy obesity (MHO) has genetic predisposing factors, and whether MHO ultimately succumbs to IR and the metabolic syndrome, indicating a need for prophylatic bariatric surgery.

Dietary Modulation of Gut Microbiota Contributes to Alleviation of Both Genetic and Simple Obesity in Children

Gut microbiota has been implicated as a pivotal contributing factor in diet-related obesity; however, its role in development of disease phenotypes in human genetic obesity such as Prader-Willi syndrome (PWS) remains elusive. In this hospitalized intervention trial with PWS (n = 17) and simple obesity (n = 21) children, a diet rich in non-digestible carbohydrates induced significant weight loss and concomitant structural changes of the gut microbiota together with reduction of serum antigen load and alleviation of inflammation. Co-abundance network analysis of 161 prevalent bacterial draft genomes assembled directly from metagenomic datasets showed relative increase of functional genome groups for acetate production from carbohydrates fermentation. NMR-based metabolomic profiling of urine showed diet-induced overall changes of host metabotypes and identified significantly reduced trimethylamine N-oxide and indoxyl sulfate, host-bacteria co-metabolites known to induce metabolic deteriorations. Specific bacterial genomes that were correlated with urine levels of these detrimental co-metabolites were found to encode enzyme genes for production of their precursors by fermentation of choline or tryptophan in the gut. When transplanted into germ-free mice, the pre-intervention gut microbiota induced higher inflammation and larger adipocytes compared with the post-intervention microbiota from the same volunteer. Our multi-omics-based systems analysis indicates a significant etiological contribution of dysbiotic gut microbiota to both genetic and simple obesity in children, implicating a potentially effective target for alleviation.

RESEARCH IN CONTEXT

Poorly managed diet and genetic mutations are the two primary driving forces behind the devastating epidemic of obesity-related diseases. Lack of understanding of the molecular chain of causation between the driving forces and the disease endpoints retards progress in prevention and treatment of the diseases. We found that children genetically obese with Prader-Willi syndrome shared a similar dysbiosis in their gut microbiota with those having diet-related obesity. A diet rich in non-digestible but fermentable carbohydrates significantly promoted beneficial groups of bacteria and reduced toxin-producers, which contributes to the alleviation of metabolic deteriorations in obesity regardless of the primary driving forces.

Immune-metabolic profiling of anorexic patients reveals an anti-oxidant and anti-inflammatory phenotype

CONTEXT

Anorexia nervosa (AN) is an excessive form of calorie restriction (CR) associated with pathological weight loss and alterations of the immune system. However, AN patients seem to be protected from common viral infections.

OBJECTIVES

To investigate the metabolic and molecular adaptations induced by sustained extreme CR in the peripheral blood mononuclear cells (PBMCs) of patients with restrictive alimentary AN.

DESIGN

Inflammatory cytokines and adipokines were measured in 15 young (age range, 15-24 years) AN female patients and 20 age-matched healthy controls. Isolated PBMCs were immunophenotyped by flow cytometry, and glycolysis and mitochondrial respiration were determined by measuring the extracellular acidification and oxygen consumption rate. Stress resistance to H2O2 and the antioxidant transcriptional profile of PBMCs and human fibroblasts incubated with sera from AN patients were also determined.

RESULTS

Compared with controls, AN patients (BMI, 15.9±0.4 kg/m(2)) had significantly fewer leucocytes, lymphocytes and NK cells, lower serum concentrations of leptin, IGF-1 and sTNFR1, and higher levels of adiponectin, sCD40L and sICAM-1 (p<0.05). IL-1β, TNFα, and IL-6 produced by PBMC cultured with autologous serum for 48 h were significantly lower in AN patients than in controls (p<0.01). Moreover, glycolysis and mitochondrial respiration were lower, and the antioxidant transcriptional profile was higher in the PBMCs of AN patients. Fibroblasts cultured in serum from AN patients showed a 24% increase in resistance to H2O2 damage.

CONCLUSIONS

Extreme CR in AN patients is associated with a reduction in several immune cell populations, but with higher antioxidant potential, stress resistance and an anti-inflammatory status.

Differential effects of leptin and adiponectin in endothelial angiogenesis

Obesity is a major health burden with an increased risk of cardiovascular morbidity and mortality. Endothelial dysfunction is pivotal to the development of cardiovascular disease (CVD). In relation to this, adipose tissue secreted factors termed "adipokines" have been reported to modulate endothelial dysfunction. In this review, we focus on two of the most abundant circulating adipokines, that is, leptin and adiponectin, in the development of endothelial dysfunction. Leptin has been documented to influence a multitude of organ systems, that is, central nervous system (appetite regulation, satiety factor) and cardiovascular system (endothelial dysfunction leading to atherosclerosis). Adiponectin, circulating at a much higher concentration, exists in different molecular weight forms, essentially made up of the collagenous fraction and a globular domain, the latter being investigated minimally for its involvement in proinflammatory processes including activation of NF-κβ and endothelial adhesion molecules. The opposing actions of the two forms of adiponectin in endothelial cells have been recently demonstrated. Additionally, a local and systemic change to multimeric forms of adiponectin has gained importance. Thus detailed investigations on the potential interplay between these adipokines would likely result in better understanding of the missing links connecting CVD, adipokines, and obesity.

Increased cardiometabolic risk factors and inflammation in adipose tissue in obese subjects classified as metabolically healthy

OBJECTIVE

It has been suggested that individuals with the condition known as metabolically healthy obesity (MHO) may not have the same increased risk for the development of metabolic abnormalities as their non-metabolically healthy counterparts. However, the validity of this concept has recently been challenged, since it may not translate into lower morbidity and mortality. The aim of the current study was to compare the cardiometabolic/inflammatory profile and the prevalence of impaired glucose tolerance (IGT) and type 2 diabetes (T2D) in patients categorized as having MHO or metabolically abnormal obesity (MAO).

RESEARCH DESIGN AND METHODS

We performed a cross-sectional analysis to compare the cardiometabolic/inflammatory profile of 222 MHO and 222 MAO patients (62% women) matched by age, including 255 lean subjects as reference (cohort 1). In a second cohort, we analyzed the adipokine profile and the expression of genes involved in inflammation and extracellular matrix remodeling in visceral adipose tissue (VAT; n = 82) and liver (n = 55).

RESULTS

The cardiometabolic and inflammatory profiles (CRP, fibrinogen, uric acid, leukocyte count, and hepatic enzymes) were similarly increased in MHO and MAO in both cohorts. Moreover, above 30%of patients classified as MHO according to fasting plasma glucose exhibited IGT or T2D [corrected]. The profile of classic (leptin, adiponectin, resistin) as well as novel (serum amyloid A and matrix metallopeptidase 9) adipokines was almost identical in MHO and MAO groups in cohort 2. Expression of genes involved in inflammation and tissue remodeling in VAT and liver showed a similar alteration pattern in MHO and MAO individuals.

CONCLUSIONS

The current study provides evidence for the existence of a comparable adverse cardiometabolic profile in MHO and MAO patients; thus the MHO concept should be applied with caution. A better identification of the obesity phenotypes and a more precise diagnosis are needed for improving the management of obese individuals.

The complement system in human cardiometabolic disease

The complement system has been implicated in obesity, fatty liver, diabetes and cardiovascular disease (CVD). Complement factors are produced in adipose tissue and appear to be involved in adipose tissue metabolism and local inflammation. Thereby complement links adipose tissue inflammation to systemic metabolic derangements, such as low-grade inflammation, insulin resistance and dyslipidaemia. Furthermore, complement has been implicated in pathophysiological mechanisms of diet- and alcohol induced liver damage, hyperglycaemia, endothelial dysfunction, atherosclerosis and fibrinolysis. In this review, we summarize current evidence on the role of the complement system in several processes of human cardiometabolic disease. C3 is the central component in complement activation, and has most widely been studied in humans. C3 concentrations are associated with insulin resistance, liver dysfunction, risk of the metabolic syndrome, type 2 diabetes and CVD. C3 can be activated by the classical, the lectin and the alternative pathway of complement activation; and downstream activation of C3 activates the terminal pathway. Complement may also be activated via extrinsic proteases of the coagulation, fibrinolysis and the kinin systems. Studies on the different complement activation pathways in human cardiometabolic disease are limited, but available evidence suggests that they may have distinct roles in processes underlying cardiometabolic disease. The lectin pathway appeared beneficial in some studies on type 2 diabetes and CVD, while factors of the classical and the alternative pathway were related to unfavourable cardiometabolic traits. The terminal complement pathway was also implicated in insulin resistance and liver disease, and appears to have a prominent role in acute and advanced CVD. The available human data suggest a complex and potentially causal role for the complement system in human cardiometabolic disease. Further, preferably longitudinal studies are needed to disentangle which aspects of the complement system and complement activation affect the different processes in human cardiometabolic disease.

A stable isotope biomarker of marine food intake captures associations between n-3 fatty acid intake and chronic disease risk in a Yup'ik study population, and detects new associations with blood pressure and adiponectin

The nitrogen isotope ratio (δ(15)N) of RBCs has been proposed as a biomarker of marine food intake in Yup'ik people based on strong associations with RBC eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, EPA and DHA derive from marine fats, whereas elevated δ(15)N derives from marine protein, and these dietary components may have different biologic effects. Whether δ(15)N is similarly associated with chronic disease risk factors compared with RBC EPA and DHA is not known. We used covariate-adjusted linear models to describe biomarker associations with chronic disease risk factors in Yup'ik people, first in a smaller (n = 363) cross-sectional study population using RBC EPA, DHA, and δ(15)N, and then in a larger (n = 772) cross-sectional study population using δ(15)N only. In the smaller sample, associations of RBC EPA, DHA, and δ(15)N with obesity and chronic disease risk factors were similar in direction and significance: δ(15)N was positively associated with total, HDL, and LDL cholesterol, apolipoprotein A-I, and insulin-like growth factor binding protein-3 (IGFBP-3), and inversely associated with triglycerides. Based on comparisons between covariate-adjusted β-coefficients, EPA was more strongly associated with circulating lipids and lipoproteins, whereas δ(15)N was more strongly associated with adipokines, the inflammatory marker interleukin-6, and IGFBP-3. In the larger sample there were new findings for this population: δ(15)N was inversely associated with blood pressure and there was a significant association (with inverse linear and positive quadratic terms) with adiponectin. In conclusion, δ(15)N is a valid measure for evaluating associations between EPA and DHA intake and chronic disease risk in Yup'ik people and may be used in larger studies. By measuring δ(15)N, we report beneficial associations of marine food intake with blood pressure and adiponectin, which may contribute to a lower incidence of some chronic diseases in Yup'ik people.

The prediction role of indexes of circulating adipokines for common anthropometric and nutritional characteristics of obesity in the obese Central European population

AIMS

This study was designed to investigate the relationship between 8 selected adipokines (leptin, leptin receptor, adiponectin, agouti-related peptide, omentin, visfatin, adipsin and resistin), dietary composition and anthropometric parameters found in the Central European obese population.

METHODS

A total of 65 unrelated obese Central European Caucasian individuals were recruited for the study. Phenotypic measurements included weight, height, BMI, lean body mass, fat mass, body fat, waist and hip circumference, waist-hip ratio (WHR) and skinfold thickness. Participants completed standardized self-reported 7-day food records. Plasma levels of leptin, leptin receptor, adiponectin, agouti-related peptide (AgRP), resistin, adipsin, omentin and visfatin were examined using ELISA.

RESULTS

Multiple associations (weight, height, percentage of body fat, waist circumference, hip circumference, WHR and sum of skinfold thickness) with the circulation levels of the investigated adipokines were identified. Leptin-Leptin receptor (L-LR) levels were found to correlate with total energy intake and macronutrients while adipsin was found to strongly correlate with multiple adipokines. Furthermore, the L-LR index was found to constitute a more accurate description of the relationship between BMI and body weight than individual measurements and the Ag-LR index was found to strongly correlate with both anthropometric and dietary characteristics.

CONCLUSION

Following confirmation on larger population samples and on samples of different ethnicities, the reported adipokine indexes could become a useful tool for estimating nutritional status and predicting the body composition of specific patient groups.

Obesity, energy balance, and cancer: a mechanistic perspective

Nearly 36 % of adults and 20 % of children in the USA are obese, defined as a body mass index (BMI) ≥30 kg/m(2). Obesity, which is accompanied by metabolic dysregulation often manifesting in the metabolic syndrome, is an established risk factor for many cancers. Within the growth-promoting, proinflammatory environment of the obese state, cross talk between macrophages, adipocytes, and epithelial cells occurs via obesity-associated hormones, cytokines, and other mediators that may enhance cancer risk and/or progression. This chapter synthesizes the evidence on key biological mechanisms underlying the obesity-cancer link, with particular emphasis on obesity-associated enhancements in growth factor signaling, inflammation, and vascular integrity processes, as well as obesity-dependent microenvironmental perturbations, including the epithelial-to-mesenchymal transition. These interrelated pathways represent possible mechanistic targets for disrupting the obesity-cancer link.

The FTO gene polymorphism (rs9939609) is associated with metabolic syndrome in morbidly obese subjects from southern Italy

Gene variants in MC4R, SIRT1 and FTO are associated with severe obesity and metabolic impairment in Caucasians. We investigated whether common variants in these genes are associated with metabolic syndrome (MetS) in a large group of morbidly obese young adults from southern Italy. One thousand morbidly obese subjects (62% women, mean body mass index 46.5 kg/m(2), mean age 32.6 years) whose families had lived in southern Italy for at least 2 generations were recruited. Single-nucleotide polymorphisms (SNPs) rs12970134, rs477181, rs502933 (MC4R locus), rs3818292, rs7069102, rs730821, rs2273773, rs12413112 (SIRT1 locus) and rs1421085, rs9939609, 9930506, 1121980 (FTO locus) were genotyped by Taqman assay; blood parameters were assayed by routine methods; the Fat Mass, Fat Free Mass, Respiratory Quotient, Basal Metabolic Rate (BMR) and waist circumference were also determined. Binomial logistic regression showed that the TA heterozygous genotype of SNP rs9939609 in the FTO gene was associated with the presence of MetS in our population [OR (95% CI): 2.53 (1.16-5.55)]. Furthermore, the FTO rs9939609 genotype accounted for 21.3% of the MetS phenotype together with total cholesterol, BMR and age. Our results extend the knowledge on genotype susceptibility for MetS in relation to a specific geographical area of residence.

The adipokine profile of metabolically benign obese and at-risk normal weight postmenopausal women: the Women's Health Initiative Observational Study

OBJECTIVE

Nearly, a third of obese individuals, termed metabolically benign obese, have a low burden of adiposity-related cardiometabolic abnormalities, whereas a substantial proportion of normal-weight individuals possess risk factors.

METHODS

In cross-sectional analyses of 699 normal weight and 1,294 overweight/obese postmenopausal women enrolled in a nested case-control stroke study ancillary to the Women's Health Initiative Observational Study, we compared levels of adiponectin, leptin, and resistin among metabolically benign normal weight, at-risk normal weight, metabolically benign obese, and at-risk obese women using components of the ATP III definition of the metabolic syndrome (metabolically benign: ≤1 of the four components; at-risk phenotype: ≥2 components or diabetes).

RESULTS

Overall, 382/699 normal-weight women (54.6%) and 328/1,194 overweight/obese women (27.5%) were metabolically benign. Among normal-weight women, at-risk women had higher leptin and lower adiponectin levels compared to metabolically benign women; multivariate-adjusted odds ratios were significant for having leptin (OR: 2.51; 95% CI: 1.28-5.01) and resistin (1.46; 1.03-2.07) in the top tertile and adiponectin in the bottom tertile (2.64; 1.81-3.84). Compared to metabolically benign overweight/obese women, at-risk obese women had higher odds of having leptin in the top tertile (1.62; 1.24-2.12) and adiponectin in the bottom tertile (2.78; 2.04-3.77).

CONCLUSIONS

Overall, metabolically benign overweight/obese women had an intermediate adipokine profile (between at-risk obese and metabolically benign normal-weight women), whereas at-risk normal-weight women had a less favorable profile compared to metabolically benign normal-weight women. As adiponectin was the only adipokine independent of BMI, it may be most likely to have a role in the etiological pathway of these phenotypes.

Circulating Adipokines in Healthy versus Unhealthy Overweight and Obese Subjects

It is now well established that not all obese subjects are at increased risk of cardiometabolic complications; such patients are termed the metabolically healthy obese. Despite their higher-than-normal body fat mass, they are still insulin sensitive, with a favorable inflammatory and lipid profile and no signs of hypertension. It remains unclear which factors determine an individual's metabolic health. Adipose tissue is known to secrete multiple bioactive substances, called adipokines, that can contribute to the development of obesity-associated complications. The goal of this study was to determine whether the circulating adipokine profiles differs between metabolically healthy and metabolically unhealthy overweight and obese subjects, thereby obtaining data that could help to explain the link between obesity and its related cardiometabolic complications. We defined metabolic health in terms of several metabolic and inflammatory risk factors. The serum adiponectin levels were higher in the healthy group and showed a positive correlation with HDL cholesterol levels in the unhealthy group. There were no differences between the two groups in the levels of serum leptin, chemerin and orosomucoid. Accordingly, adiponectin might play a role in protecting against obesity-associated cardiometabolic derangements. More studies are needed to clarify the role of different chemerin isoforms in this system.

Ectopic fat and adipokines in metabolically benign overweight/obese women: the Kronos Early Estrogen Prevention Study

OBJECTIVE

It is unclear why despite a comparable cardiometabolic risk profile, "metabolically benign" overweight/obese individuals show an elevated risk of cardiovascular disease compared to normal weight individuals.

DESIGN AND METHODS

In cross-sectional analyses, we compared levels of ectopic fat (epicardial, pericardial, and hepatic fat) and adipokines (leptin, soluble leptin receptor, and high molecular weight [HMW] adiponectin) among metabolically benign (MBO) and at-risk overweight/obese (ARO), and metabolically benign normal weight (MBNW) women, screened for the Kronos Early Estrogen Prevention Study. We defined "metabolically benign" with ≤ 1, and "at-risk" with ≥2 components of the metabolic syndrome.

RESULTS

Compared to MBO women, ARO women had significantly elevated odds of being in the top tertile of epicardial fat (OR: 1.76, 95% CI: 1.04-2.99), hepatic fat (OR: 1.90, 95% CI:1.12-3.24) and leptin (OR: 2.15, 95% CI: 1.23-3.76), and the bottom tertile of HMW-adiponectin (OR: 2.90, 95% CI: 1.62-5.19). Compared to MBNW women, MBO women had significantly higher odds of being in the top tertile of epicardial fat (OR: 5.17, 95% CI: 3.22-8.29), pericardial fat (OR: 9.27, 95% CI: 5.52-15.56) and hepatic fat (OR: 2.72, 95% CI: 1.77-4.19) and the bottom tertile of HMW adiponectin levels (OR: 2.51, 95% CI: 1.60-3.94).

CONCLUSIONS

Levels of ectopic fat and the adverse adipokine profile increase on a continuum of BMI, suggesting that the metabolically benign phenotype may be a transient state.

High aminopeptidase N/CD13 levels characterize human amniotic mesenchymal stem cells and drive their increased adipogenic potential in obese women

Maternal obesity is associated to increased fetal risk of obesity and other metabolic diseases. Human amniotic mesenchymal stem cells (hA-MSCs) have not been characterized in obese women. The aim of this study was to isolate and compare hA-MSC immunophenotypes from obese (Ob-) and normal weight control (Co-) women, to identify alterations possibly predisposing the fetus to obesity. We enrolled 16 Ob- and 7 Co-women at delivery (mean/SEM prepregnancy body mass index: 40.3/1.8 and 22.4/1.0 kg/m2, respectively), and 32 not pregnant women. hA-MSCs were phenotyped by flow cytometry; several maternal and newborn clinical and biochemical parameters were also measured. The expression of membrane antigen CD13 was higher on Ob-hA-MSCs than on Co-hA-MSCs (P = 0.005). Also, serum levels of CD13 at delivery were higher in Ob- versus Co-pregnant women and correlated with CD13 antigen expression on Ob-hA-MSCs (r2 = 0.84, P < 0.0001). Adipogenesis induction experiments revealed that Ob-hA-MSCs had a higher adipogenic potential than Co-hA-MSCs as witnessed by higher peroxisome proliferator-activated receptor gamma and aP2 mRNA levels (P = 0.05 and P = 0.05, respectively), at postinduction day 14 associated with increased CD13 mRNA levels from baseline to day 4 postinduction (P < 0.05). Adipogenesis was similar in the two sets of hA-MSCs after CD13 silencing, whereas it was increased in Co-hA-MSCs after CD13 overexpression. CD13 expression was high also in Ob-h-MSCs from umbilical cords or visceral adipose tissue of not pregnant women. In conclusion, antigen CD13, by influencing the adipogenic potential of hA-MSCs, could be an in utero risk factor for obesity. Our data strengthen the hypothesis that high levels of serum and MSC CD13 are obesity markers.

Prevalence of metabolic syndrome in a cohort of Chinese schoolchildren: comparison of two definitions and assessment of adipokines as components by factor analysis

BACKGROUND

Although attention to metabolic syndrome (MetS) in children has increased, there is still no universally accepted definition and its pathogenesis remains unclear. Our aim was to compare the current definitions of childhood MetS in a Chinese cohort and to examine the clustering pattern of MetS risk factors, particularly inclusion of leptin and adiponectin as additional components.

METHODS

3373 schoolchildren aged 6 to 18 years were recruited. Anthropometric and biochemical parameters and adipokines were measured. MetS was identified using both the International Diabetes Federation (IDF) and a modified Adult Treatment Panel III (ATP III) definitions. Exploratory factor analysis was performed to establish grouping of metabolic characteristics.

RESULTS

For children ≥ 10 years, the prevalence of MetS was 14.3% in the obese group and 3.7% in the overweight group according to the new IDF definition, and 32.3% in the obese group and 8.4% in the overweight group according to the modified ATPIII definition. Frequency of hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), impaired fasting glucose, elevated blood pressure, and central obesity according to the new IDF definition was 16.7%, 20.7%, 15.8%, 25.5% and 75.5% in obese boys and 14.7%, 24.0%, 12.0%, 11.0% and 89.0% in obese girls, respectively. Metabolic abnormalities in children under 10 years of age were also noted. Using factor analysis on eight conventional variables led to the extraction of 3 factors. Waist circumference (WC) provided a connection between two factors in boys and all three factors in girls, suggesting its central role in the clustering of metabolic risk factors. Addition of leptin and adiponectin also led to the extraction of 3 factors, with leptin providing a connection between two factors in girls. When using WC, mean arterial pressure, triglyceride/HDL-C ratio, HOMA-IR and leptin/adiponectin ratio as variables, a single-factor model was extracted. WC had the biggest factor loading, followed by leptin/adiponectin ratio.

CONCLUSIONS

MetS was highly prevalent amongst obese children and adolescents in this cohort, regardless of the definition used. Central obesity is the key player in the clustering of metabolic risk factors in children, supporting the new IDF definition. Moreover, our findings suggest that a common factor may underlie MetS. Leptin/adiponectin ratio as a possible component of MetS deserves further consideration.

Calorie restriction and cancer prevention: a mechanistic perspective

Calorie restriction (CR) is one of the most potent broadly acting dietary interventions for inducing weight loss and for inhibiting cancer in experimental models. Translation of the mechanistic lessons learned from research on CR to cancer prevention strategies in human beings is important given the high prevalence of excess energy intake, obesity, and metabolic syndrome in many parts of the world and the established links between obesity-associated metabolic perturbations and increased risk or progression of many types of cancer. This review synthesizes findings on the biological mechanisms underlying many of the anticancer effects of CR, with emphasis on the impact of CR on growth factor signaling pathways, inflammation, cellular and systemic energy homeostasis pathways, vascular perturbations, and the tumor microenvironment. These CR-responsive pathways and processes represent targets for translating CR research into effective cancer prevention strategies in human beings.

Analysis of adipose tissues and stromal vascular cells in a murine arthritis model

PURPOSE

Changes in body composition in rheumatoid arthritis (RA), including a reduction in skeletal muscle mass and the accumulation of visceral fat, have been identified, and the interaction between immune abnormality and metabolic disorders has received much attention. The effect of a high-fat (HF) diet and the role of adipose tissue in an arthritis model were investigated.

METHODS

The effect of an HF diet on the histopathology of joints in murine type II collagen-induced arthritis (CIA) was evaluated. The morphology and adipokine production of adipose tissues were analyzed, and macrophages in the stromal vascular fraction (SVF) were counted by flow cytometry. Serum adipokine levels were measured by ELISA.

RESULTS

Significant exacerbation of joint destruction and aggravated pathological conditions were observed in CIA mice that were fed an HF diet. However, the boundary length of adipose tissue tended to decrease and the levels of adipokines (leptin and adiponectin) were lowered by the induction of arthritis. In HF/CIA mice, nevertheless, the production of MCP-1 in adipose tissues and the accumulation of macrophages in the SVF were significantly higher than CON/CIA group. The serum leptin/adiponectin (L/A) ratio was positively correlated with the number of macrophages in the SVF and MCP-1 production by adipose tissue, particularly in the CIA group.

CONCLUSION

Functional alterations of adipose tissues could be originated from HF diet during developing arthritis. An abnormal activation of macrophages and an increased production of MCP-1 in adipose tissues might be both involved in joint destruction and inflammation.

Growth signals, inflammation, and vascular perturbations: mechanistic links between obesity, metabolic syndrome, and cancer

Nearly 35% of adults and 20% of children in the United States are obese, defined as a body mass index ≥ 30 kg/m(2). Obesity, which is accompanied by metabolic dysregulation often manifesting in the metabolic syndrome, is an established risk factor for many cancers. Within the growth-promoting, proinflammatory environment of the obese state, cross talk between macrophages, adipocytes, and epithelial cells occurs via obesity-associated hormones, cytokines, and other mediators that may enhance cancer risk and progression. This review synthesizes the evidence on key biological mechanisms underlying the obesity-cancer link, with particular emphasis on obesity-associated enhancements in growth factor signaling, inflammation, and vascular integrity processes. These interrelated pathways represent possible mechanistic targets for disrupting the obesity-cancer link.

Cytosolic malic enzyme 1 (ME1) mediates high fat diet-induced adiposity, endocrine profile, and gastrointestinal tract proliferation-associated biomarkers in male mice

BACKGROUND

Obesity and associated hormonal disturbances are risk factors for colon cancer. Cytosolic Malic Enzyme (ME1) generates NADPH used for lipogenesis in gastrointestinal (GI), liver and adipose tissues. We have reported that inclusion of soy protein isolate (SPI) in the diet lowered body fat content and colon tumor incidence of rats fed AIN-93G diet, while others have demonstrated SPI inhibition of rat hepatic ME1 expression. The present study examined the individual and combined effects of dietary SPI and absence of ME1 on: 1) serum concentrations of hormones implicated in colon cancer development, 2) expression of lipogenic and proliferation-associated genes in the mouse colon and small intestine, and 3) liver and adipose expression of lipogenic and adipocytokine genes that may contribute to colon cancer predisposition.

METHODS

Weanling wild type (WT) and ME1 null (MOD-1) male mice were fed high-fat (HF), iso-caloric diets containing either casein (CAS) or SPI as sole protein source for 5 wks. Somatic growth, serum hormone and glucose levels, liver and adipose tissue weights, GI tissue parameters, and gene expression were evaluated.

RESULTS

The MOD-1 genotype and SPI-HF diet resulted in decreases in: body and retroperitoneal fat weights, serum insulin, serum leptin, leptin/adiponectin ratio, adipocyte size, colon mTOR and cyclin D1 mRNA abundance, and jejunum FASN mRNA abundance, when compared to WT mice fed CAS-HF. Regardless of diet, MOD-1 mice had reductions in liver weight, liver steatosis, and colon crypt depth, and increases in adipose tissue expression of IRS1 and IRS2, compared to WT mice. SPI-HF diet reduced ME1 gene expression only in retroperitoneal fat.

CONCLUSIONS

Data suggest that the pharmacological targeting of ME1 or the inclusion of soy protein in the diet may provide avenues to reduce obesity and its associated pro-tumorigenic endocrine environment and improve insulin sensitivity, potentially disrupting the obesity-colon cancer connection.