Association between serum leptin concentrations and insulin resistance: a population-based study from China

Biomarkers of insulin sensitivity/resistance

In recent years, remarkable advancements in elucidating the intricate molecular underpinnings of type 2 diabetes mellitus (T2D) have been achieved. Insulin resistance (IR) has been unequivocally acknowledged as the driving pathogenetic mechanism of T2D, preceding disease onset by several years. Nonetheless, diagnostic tools for ascertaining IR are lacking in current clinical practice, representing a critical unmet need; use of the hyperinsulinemic-euglycemic glucose clamp, widely accepted as the gold standard method for evaluating IR at present, is cumbersome in a clinical setting. Thus, the development of well-validated, reliable, and affordable biomarkers of IR has attracted considerable attention from the research community. The biomarkers under investigation can be divided into two major categories: (1) indices or ratios, comprising parameters obtained from a basic or comprehensive metabolic panel and/or derived from anthropometric measurements, and (2) circulating molecules implicated in pathophysiological processes associated with IR. Furthermore, numerous novel biomarkers, including markers of β-cell dysfunction, radiographic quantification of excess visceral adipose tissue, T2D prediction models, certain microRNAs and metabolomic biomarkers, have also provided promising preliminary results. This narrative review aims to present current evidence pertaining to the most notable and exciting biomarkers of IR that are under rigorous evaluation.

Metabolic Syndrome: A Narrative Review from the Oxidative Stress to the Management of Related Diseases

Metabolic syndrome (MS) is a growing disorder affecting thousands of people worldwide, especially in industrialised countries, increasing mortality. Oxidative stress, hyperglycaemia, insulin resistance, inflammation, dysbiosis, abdominal obesity, atherogenic dyslipidaemia and hypertension are important factors linked to MS clusters of different pathologies, such as diabesity, cardiovascular diseases and neurological disorders. All biochemical changes observed in MS, such as dysregulation in the glucose and lipid metabolism, immune response, endothelial cell function and intestinal microbiota, promote pathological bridges between metabolic syndrome, diabesity and cardiovascular and neurodegenerative disorders. This review aims to summarise metabolic syndrome's involvement in diabesity and highlight the link between MS and cardiovascular and neurological diseases. A better understanding of MS could promote a novel strategic approach to reduce MS comorbidities.

The Response of Antioxidant Enzymes and Antiapoptotic Markers to an Oral Glucose Tolerance Test (OGTT) in Children and Adolescents with Excess Body Weight

Oxidative stress and apoptosis are involved in the pathogenesis of obesity-related diseases. This observational study investigates the antioxidant and apoptotic markers response to an oral glucose tolerance test (OGTT) in a population of overweight children and adolescents, with normal (NGT) or impaired glucose tolerance (IGT). Glucose, insulin, and C-peptide concentrations, as well as oxidative stress (SOD, GPx3) and apoptotic markers (Apo1fas, cck18), were determined at T = 0, 30, 60, 90, 120, and 180 min after glucose intake during OGTT. The lipid profile, thyroid function, insulin-like growth factor1, leptin, ghrelin, and adiponectin were also measured at baseline. The 45 participants, with a mean age of 12.15 (±2.3) years old, were divided into two subcategories: those with NGΤ (n = 31) and those with IGT (n = 14). The area under the curve (AUC) of glucose, insulin, and C-peptide was greater in children with IGT; however, only glucose differences were statistically significant. SOD and GPx3 levels were higher at all time points in the IGT children. Apo1fas and cck18 levels were higher in the NGT children at most time points, whereas Adiponectin was lower in the IGT group. Glucose increased during an OGTT accompanied by a simultaneous increase in antioxidant factors, which may reflect a compensatory mechanism against the impending increase in oxidative stress in children with IGT.

Enhancement of biochemical and genomic pathways through lycopene-loaded nano-liposomes: Alleviating insulin resistance, hepatic steatosis, and autophagy in obese rats with non-alcoholic fatty liver disease: Involvement of SMO, GLI-1, and PTCH-1 genes

Non-alcoholic fatty liver (NAFL) is a prevalent hepatic disorder of global significance that can give rise to severe complications. This research endeavor delves into the potential of nano-liposomal formulated Lycopene (Lip-Lyco) in averting the development of obesity and insulin resistance, both of which are major underlying factors contributing to NAFL. The investigation further scrutinizes the impact of Lip-Lyco on intricate cellular pathways within the liver tissue of rats induced with NAFL, specifically focusing on the progression of steatosis and fibrosis. To establish an obesity-NAFL model, twenty rats were subjected to a high-fat diet (HFD) for a duration of twelve weeks, after which they received an oral treatment of Lip-Lyco (10mg/kg) for an additional eight weeks. Another group of sixteen non-obese rats were subjected to treatment with or without Lip-Lyco, serving as a control for comparison. Results: The rats on a hypercaloric diet had high body mass index (BMI) and insulin resistance, reflected in disturbed serum adipokines and lipid profiles. Oxidative stress, inflammation, and apoptosis were evident in hepatic tissue, and the autophagic process in hepatocytes was inhibited. Additionally, the hedgehog pathway was activated in the liver tissue of NAFL group. Lip-Lyco was found to counteract all these aspects of NAFL pathogenesis. Lip-Lyco exhibited antioxidant, anti-inflammatory, hypoglycemic, antiapoptotic, autophagy-inducing, and Hedgehog signaling inhibitory effects. This study concludes that Lip-Lyco, a natural compound, has promising therapeutic potential in combating NAFLdisease. However, more experimental and clinical studies are required to confirm the effectiveness of lycopene in treating NAFLdisease.

Association between serum leptin concentrations and homeostasis model assessment-insulin resistance of 2.5 and higher in normal weight Japanese women

Normal weight insulin resistant phenotype was characterized in 251 Japanese female university students using homeostasis model assessment-insulin resistance. Birth weight, body composition at age 20, cardiometabolic traits and dietary intake were compared cross-sectionally between insulin sensitive (< 1.6, n = 194) and insulin resistant (2.5 and higher, n = 16) women. BMI averaged < 21 kg/m² and waist < 72 cm and did not differ between two groups. The percentage of macrosomia and serum absolute and fat-mass corrected leptin concentrations were higher in insulin resistant women although there was no difference in birth weight, fat mass index, trunk/leg fat ratio and serum adiponectin. In addition, resting pulse rate, serum concentrations of free fatty acids, triglycerides and remnant-like particle cholesterol were higher in insulin resistant women although HDL cholesterol and blood pressure did not differ. In multivariate logistic regression analyses, serum leptin (odds ratio:1.68, 95% confidential interval:1.08-2.63, p = 0.02) was associated with normal weight insulin resistance independently of macrosomia, free fatty acids, triglycerides, remnant-like particle cholesterol and resting pulse rate. In conclusion, normal weight IR phenotype may be associated with increased plasma leptin concentrations and leptin to fat mass ratio in young Japanese women, suggesting higher leptin production by body fat unit.

White Adipose Tissue Dysfunction: Pathophysiology and Emergent Measurements

White adipose tissue (AT) dysfunction plays an important role in the development of cardiometabolic alterations associated with obesity. AT dysfunction is characterized by the loss of the expansion capacity of the AT, an increment in adipocyte hypertrophy, and changes in the secretion profile of adipose cells, associated with accumulation of macrophages and inflammation. Since not all people with an excess of adiposity develop comorbidities, it is necessary to find simple tools that can evidence AT dysfunction and allow the detection of those people with the potential to develop metabolic alterations. This review focuses on the current pathophysiological mechanisms of white AT dysfunction and emerging measurements to assess its functionality.

Cytokine modulation by etanercept ameliorates metabolic syndrome and its related complications induced in rats administered a high-fat high-fructose diet

The aim of the present study was to investigate the effect of etanercept (ETA)-an anti-tumor necrosis factor α (TNF-α) monoclonal antibody-on metabolic disorders such as obesity, hypertension, dyslipidemia, and insulin resistance associated with the metabolic syndrome (MS). MS was induced in rats via high-fat high-fructose (HFHF) administration for 8 weeks. Rats were divided into three groups: negative control, HFHF model, and ETA-treated groups [HFHF + ETA (0.8 mg/kg/twice weekly, subcutaneously) administered in the last 4 weeks]. ETA effectively diminished the prominent features of MS via a significant reduction in the percent body weight gain along with the modulation of adipokine levels, resulting in a significant elevation of serum adiponectin consistent with TNF-α and serum leptin level normalization. Moreover, ETA enhanced dyslipidemia and the elevated blood pressure. ETA managed the prominent features of MS and its associated complications via the downregulation of the hepatic inflammatory pathway that induces nonalcoholic steatohepatitis (NASH)-from the expression of Toll-like receptor 4, nuclear factor kappa B, and TNF-α until that of transforming growth factor-in addition to significant improvements in glucose utilization, insulin sensitivity, and liver function parameter activity and histopathological examination. ETA was effective for the treatment of all prominent features of MS and its associated complications, such as type II diabetes mellitus and NASH.

Role of Appetite Hormone Dysregulation in Symptomology and Executive Function in Adolescents With Attention Deficit Hyperactivity Disorder

BACKGROUND

Evidence suggests an association of insulin and leptin with attention and executive function. The roles of dysregulated appetite hormones, including insulin and leptin, in the pathomechanisms of attention deficit hyperactivity disorder (ADHD) and associated cognitive function impairment remain unknown.

METHODS

In total, 50 adolescents with ADHD were enrolled and age and sex matched with 50 typically developing controls. The parent-reported Swanson, Nolan, and Pelham IV scale and self-reported Barratt Impulsiveness Scale were employed for symptom assessment. The fasting serum concentrations of appetite hormones-leptin, ghrelin, insulin, and adiponectin-were measured. The Wisconsin Card Sorting Test was used to examine executive function.

RESULTS

Generalized linear models with adjustment for age, sex, body mass index, and medications indicated that the adolescents with ADHD had higher levels of insulin (P = .039) and leptin (P = .006) than did those in the control group. Self-reported attention and self-control symptoms were negatively associated with insulin level (P = .025 and .018, respectively) and positively associated with leptin level (both P < .001). In addition, insulin level was positively associated with executive function (P = .031).

CONCLUSION

Appetite hormone dysregulation was associated with the symptomology and executive function among adolescents with ADHD. Our results may inspire researchers to further examine the role of appetite hormone dysregulation in ADHD pathogenesis.

Association of 25 (OH) Vitamin D and Leptin in Individuals with Insulin Resistance

Introduction

Asian-Indian individuals with diabetes have been shown to have low vitamin D levels. Whether this hypovitamonisis D is associated with hyperleptinaemia is unclear. Also, whether this association is different in those with and without insulin resistance has not been ascertained. The present study aimed to investigate the association of 25-hydroxy vitamin D [25(OH) vitamin D] and leptin in individuals with and without insulin resistance.

Methods

Ninety two individuals were recruited in two study groups (n = 46 each group). First group included individuals with insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR] ≥2.0). Second group included those without insulin resistance (HOMA-IR <2.0). Comparison of 25(OH) vitamin D, leptin, anthropometry, and biochemical parameters was done between two groups and correlations between 25(OH) vitamin D, leptin, and HOMA-IR were studied.

Results

Individuals with insulin resistance were of simiar age (39.6 ± 5.3 years) and body mass index (24.4 ± 3.2 kg/m2) as those without (39.5 ± 5.2 years and 23.6 ± 3.2 kg/m2). Individuals with insulin resistance showed significantly lower 25(OH) vitamin D (17.8 ± 7.1 vs. 22.3 ± 11.6 ng/mL, P = .03) and significantly higher leptin levels (16.9 ± 15.8 vs. 9.6 ± 9.3 ng/mL, P = .09) compared to those without. Significant negative correlation was observed between 25(OH) vitamin D and leptin levels overall (r = -0.3, P = .008). HOMA-IR showed significantly negative correlation with 25(OH) vitamin D levels in individuals with insulin resistance (r = -0.33, P = .027).

Conclusion

The present study found higher circulating leptin levels and lower 25(OH) vitamin D levels in individuals with insulin resistance. 25(OH) vitamin D levels were inversely associated with leptin levels particularly in women.

Altered Circulating Leptin, hGH, and IGF-I in Prediabetes and Screening-Diagnosed T2DM Unrelated to Metabolic Syndrome in Women Post Gestational Diabetes

Recently, we proposed two pathophysiologic subtypes of type 2 diabetes mellitus (T2DM), one related and one unrelated to metabolic syndrome. To begin to understand the pathophysiology of the subtype unrelated to metabolic syndrome, we now measured selected hormones and signaling molecules in affected individuals. In this cross-sectional analysis, we examined 138 women out of the monocenter, post gestational diabetes study PPSDiab. Of these women, 73 had prediabetes or screening-diagnosed T2DM, 40 related to metabolic syndrome and 33 unrelated. The remaining 65 women were normoglycemic controls. Our analysis included medical history, anthropometrics, oral glucose tolerance testing, laboratory chemistry, and cardiopulmonary exercise testing. In addition, plasma proinsulin/insulin ratio, growth hormone (hGH) nadir during oral glucose tolerance testing, Insulin-like Growth Factor I (IGF-I), Leptin, Resistin, Adiponectin, Fetuin-a, FGF21, and myostatin were measured. Compared to controls, women with prediabetes or screening-diagnosed T2DM unrelated to metabolic syndrome depicted higher plasma Leptin [10.47(6.6-14.57) vs. 5.52(3.15-10.02); p<0.0001] and IGF-I [193.01(171.00-213.30) vs. 167.97(138.77-200.64); p=0.0008], as well as a lower hGH nadir [0.07(0.05-0.15) vs. 0.14(0.08-0.22; p<0.0001]. These differences were independent of body adiposity. Women with prediabetes or T2DM related to metabolic syndrome, in comparison to controls, displayed elevated Leptin, Fetuin-a, and FGF21, as well as reduced Adiponectin and hGH nadir. Based on our study, altered Leptin and hGH/IGF-I signaling could potentially contribute to the pathophysiology of prediabetes and T2DM unrelated to metabolic syndrome. Further mechanistic investigations of these signaling pathways in the context of lean T2DM are necessary to test causal relationships.

Adipose Tissue Secretion Pattern Influences β-Cell Wellness in the Transition from Obesity to Type 2 Diabetes

The dysregulation of the β-cell functional mass, which is a reduction in the number of β-cells and their ability to secure adequate insulin secretion, represents a key mechanistic factor leading to the onset of type 2 diabetes (T2D). Obesity is recognised as a leading cause of β-cell loss and dysfunction and a risk factor for T2D. The natural history of β-cell failure in obesity-induced T2D can be divided into three steps: (1) β-cell compensatory hyperplasia and insulin hypersecretion, (2) insulin secretory dysfunction, and (3) loss of β-cell mass. Adipose tissue (AT) secretes many hormones/cytokines (adipokines) and fatty acids that can directly influence β-cell function and viability. As this secretory pattern is altered in obese and diabetic patients, it is expected that the cross-talk between AT and pancreatic β-cells could drive the maintenance of the β-cell integrity under physiological conditions and contribute to the reduction in the β-cell functional mass in a dysmetabolic state. In the current review, we summarise the evidence of the ability of the AT secretome to influence each step of β-cell failure, and attempt to draw a timeline of the alterations in the adipokine secretion pattern in the transition from obesity to T2D that reflects the progressive deterioration of the β-cell functional mass.

Cavitation and radiofrequency versus cryolipolysis on leptin regulation in central obese subjects: A randomized controlled study

BACKGROUND AND OBJECTIVE

To investigate the efficacy of adding ultrasound cavitation and radiofrequency versus cryolipolysis to weight reduction program on leptin, insulin, waist circumference, skinfold, body weight in central obese subjects.

MATERIAL AND METHODS

Sixty centrally obese participants were randomly allocated into three equal groups. Subjects in the study group (I) received cavitation and radiofrequency plus dietary regimen, subjects in the second study group (II) received cryolipolysis in conjunction with the same diet program, and subjects in the control group (III) received the same dietary regimen only. Leptin, insulin level, waist circumference, skinfold, body weight, and body mass index were measured shortly before intervention techniques and 3 months afterward.

RESULTS

There were no statistically significant differences between cavitation plus radiofrequency and cryolipolysis on leptin and insulin levels after 3 months of intervention. However, statistically significant differences were found in waist circumference, skinfold, weight reduction, and body mass index in favor of the cavitation group (p < 0.05). In addition, both cavitation-radiofrequency and cryolipolysis were statistically significantly different than the diet alone in favor of the study groups (p < 0.05) in all the outcome measures. Furthermore, there were statistically significant differences in all outcome measures (p < 0.05) when comparing the baseline and postintervention results in each group except for leptin level in the diet group (p = 0.14).

CONCLUSION

Subjects who underwent cavitation plus radiofrequency had better improvement on waist circumference, skinfold, and body mass index than subjects who received cryolipolysis. However, no differences were found between cavitation plus radiofrequency and cryolipolysis on leptin and insulin levels.

Understanding the Role of the Gut Microbiome in Brain Development and Its Association With Neurodevelopmental Psychiatric Disorders

The gut microbiome has a tremendous influence on human physiology, including the nervous system. During fetal development, the initial colonization of the microbiome coincides with the development of the nervous system in a timely, coordinated manner. Emerging studies suggest an active involvement of the microbiome and its metabolic by-products in regulating early brain development. However, any disruption during this early developmental process can negatively impact brain functionality, leading to a range of neurodevelopment and neuropsychiatric disorders (NPD). In this review, we summarize recent evidence as to how the gut microbiome can influence the process of early human brain development and its association with major neurodevelopmental psychiatric disorders such as autism spectrum disorders, attention-deficit hyperactivity disorder, and schizophrenia. Further, we discuss how gut microbiome alterations can also play a role in inducing drug resistance in the affected individuals. We propose a model that establishes a direct link of microbiome dysbiosis with the exacerbated inflammatory state, leading to functional brain deficits associated with NPD. Based on the existing research, we discuss a framework whereby early diet intervention can boost mental wellness in the affected subjects and call for further research for a better understanding of mechanisms that govern the gut-brain axis may lead to novel approaches to the study of the pathophysiology and treatment of neuropsychiatric disorders.

Ginsenoside compound K inhibits obesity-induced insulin resistance by regulation of macrophage recruitment and polarization via activating PPARγ

Obesity disrupts the immune system of adipose tissue, and the activation of its macrophages constantly infiltrating adipose tissue is a crucial cause of insulin resistance induced by obesity. We previously reported for the first time in vitro that the antidiabetic effect of CK may be through the inhibition of macrophage activation and we further explored the specific mechanism in vivo. In order to clarify it, the C57BL/6J mice were fed with a high fat diet and then administered with CK orally. The related biochemical indices were detected, the inflammatory factors in serum and tissues were measured, and the related protein expression levels in insulin pathways and inflammatory signaling pathways were observed. The results showed that CK could dose-dependently reduce macrophage M1-type inflammatory factor expression in serum and adipose tissue, improve insulin resistance and glucose tolerance effectively, upregulate PPARγ expression and block TLR4/TRAF6/TAK1/NF-κB activation in obese mice. In addition, CK promoted the expression of IRS1/PI3K/AKT. Furthermore, our study showed that ginsenoside CK could improve insulin resistance by reducing inflammation through the PPARγ/NF-κB signaling pathway, which implies that ginsenoside CK may be an effective agent against obesity or early diabetes.

Cardiorenal Risk Profiles Among Data-Driven Type 2 Diabetes Sub-Phenotypes: A Post-Hoc Analysis of the China Health and Nutrition Survey

BACKGROUND AND AIM

Evidence about recently proposed data-driven clusters of type 2 diabetes (T2D) is mainly about its prognostic effects and Western populations. We tested the applicability of this clustering approach among the Chinese population. We further investigated the cardiorenal risk profiles among different T2D sub-phenotypes cross-sectionally and before diabetes diagnosis.

METHODS

With the use of data from the China Health and Nutrition Survey (1989-2009), 6,728 participants with available fasting blood samples and completed questionnaires in the 2009 survey were included. Glycemic statuses (normoglycemia, prediabetes, and new-onset T2D) were defined according to the 2020 American Diabetes Association criteria. Data-driven cluster analysis was conducted among new-onset T2D based on five variables: age at onset, body mass index (BMI), hemoglobin A1c, homeostasis model estimates of β-cell function, and insulin resistance. Linear regression models were used to cross-sectionally examine the differences of cardiorenal risk factors (body fat distribution, blood pressure, lipid profiles, and kidney function) between glycemic statuses. Mixed-effects models were used to explore a maximum of 20-year trajectories of cardiovascular risk factors (body fat distribution and blood pressure) before diabetes diagnosis.

RESULTS

Among 557 (8.3%) new-onset T2D, four sub-phenotypes were found, with 57 (10.2%) assigned to the severe insulin-resistant diabetes (SIRD), 72 (12.9%) to the severe insulin-deficient diabetes (SIDD), 167 (30.0%) to the mild obesity-related diabetes (MOD), and 261 (46.9%) to the mild age-related diabetes (MARD). People clustered within different T2D sub-phenotypes had different cardiorenal risk profiles. Three T2D sub-phenotypes (SIRD, SIDD, and MOD) had worse cardiorenal abnormalities, while the risk burden in the MARD sub-phenotype was similar to that in prediabetes. Compared with people with other T2D sub-phenotypes, people in the MOD sub-phenotype had a faster increment in BMI, waist, upper arm circumference, and triceps skinfold up to 10 years before diagnosis. Blood pressure was less distinct in different T2D sub-phenotypes; however, SIDD and MOD clusters had higher blood pressure levels before diabetes diagnosis.

CONCLUSIONS

Data-driven T2D sub-phenotyping is applicable in the Chinese population. Certain sub-phenotypes such as MARD only have a minor cardiorenal risk burden, and distinct cardiovascular risk development occurs long before diabetes diagnosis. Our findings can help improve early prevention and targeted treatment for diabetes.

Alternatives for the worse: Molecular insights into adverse effects of bisphenol a and substitutes during human adipocyte differentiation

Bisphenol A (BPA), which is used in a variety of consumer-related plastic products, was reported to cause adverse effects, including disruption of adipocyte differentiation, interference with obesity mechanisms, and impairment of insulin- and glucose homeostasis. Substitute compounds are increasingly emerging but are not sufficiently investigated.We aimed to investigate the mode of action of BPA and four of its substitutes during the differentiation of human preadipocytes to adipocytes and their molecular interaction with peroxisome proliferator-activated receptor γ (PPARγ), a pivotal regulator of adipogenesis.Binding and effective biological activation of PPARγ were investigated by surface plasmon resonance and reporter gene assay, respectively. Human preadipocytes were continuously exposed to BPA, BPS, BPB, BPF, BPAF, and the PPARγ-antagonist GW9662. After 12 days of differentiation, lipid production was quantified via Oil Red O staining, and global protein profiles were assessed using LC-MS/MS-based proteomics. All tested bisphenols bound to human PPARγ with similar efficacy as the natural ligand 15d-PGJ2in vitroand provoked an antagonistic effect on PPARγ in the reporter gene assay at non-cytotoxic concentrations. During the differentiation of human preadipocytes, all bisphenols decreased lipid production. Global proteomics displayed a down-regulation of adipogenesis and metabolic pathways, similar to GW9662. Interestingly, pro-inflammatory pathways were up-regulated, MCP1 release was increased, and adiponectin decreased. pAKT/AKT ratios revealed significantly reduced insulin sensitivity by BPA, BPB, and BPS upon insulin stimulation.Thus, our results show that not only BPA but also its substitutes disrupt crucial metabolic functions and insulin signaling in adipocytes under low, environmentally relevant concentrations. This effect, mediated through inhibition of PPARγ, may promote hypertrophy of adipose tissue and increase the risk of developing metabolic syndrome, including insulin resistance.

Intergenic lnc-LEP-2:6 and lnc-LEP-2:7 as novel biomarkers associated with type 2 diabetes mellitus

CONTEXT

Type 2 diabetes mellitus (T2DM) has undeniably become a significant threat to public health in the modern world.

OBJECTIVE

To identify molecules involved in the development of T2DM, the expression patterns of cis-lincRNAs-LEP were investigated in T2DM patients.

MATERIALS AND METHODS

The expression levels of 11 lncRNAs-LEP and LEP mRNA in 71 diabetic patients and 32 controls were determined using qRT-PCR. The association between lncRNAs-LEP and T2DM was performed using ROC curve analysis.

RESULTS

The expression analysis of lnc-LEP-2:6 and lnc-LEP-2:7 was significantly different (p≤ .0001) in diabetic patients compared to the controls. The ROC curve data showed that lnc-LEP-2:6 and lnc-LEP-2:7 have a high AUC, with 0.940 (95% CI: 0.875-0.977) and 0.958 (95% CI: 0.899-0.988), respectively.

CONCLUSIONS

Our results revealed two novel biomarkers associated with the T2DM and suggest that the circulating intergenic, lnc-LEP-2:6 and lnc-LEP-2:7, might have a regulatory role in the disease pathogenesis.

Insulin Resistance and Endometrial Cancer: Emerging Role for microRNA

Endometrial cancer (EC) remains one of the most common cancers of the female reproductive system. Epidemiological and clinical data implicate insulin resistance (IR) and its accompanying hyperinsulinemia as key factors in the development of EC. MicroRNAs (miRNAs) are short molecules of non-coding endogenous RNA that function as post-transcriptional regulators. Accumulating evidence has shown that the miRNA expression pattern is also likely to be associated with EC risk factors. The aim of this work was the verification of the relationships between IR, EC, and miRNA, and, as based on the literature data, elucidation of miRNA's potential utility for EC prevention in IR patients. The pathways affected in IR relate to the insulin receptors, insulin-like growth factors and their receptors, insulin-like growth factor binding proteins, sex hormone-binding globulin, and estrogens. Herein, we present and discuss arguments for miRNAs as a plausible molecular link between IR and EC development. Specifically, our careful literature search indicated that dysregulation of at least 13 miRNAs has been ascribed to both conditions. We conclude that there is a reasonable possibility for miRNAs to become a predictive factor of future EC in IR patients.

Hypovitaminosis D and Cardiometabolic Risk Factors in Adolescents with Severe Obesity

BACKGROUND/OBJECTIVES

Obesity is associated with cardiometabolic risk factors and with Vitamin D deficiency. The aim of this study was to examine the relationship between 25(OH)D concentrations and cardiometabolic risk factors in adolescents with severe obesity.

SUBJECTS/METHODS

A cross-sectional clinical assessment (body mass index, fat mass index, fat-free mass index, waist-to-height ratio, and blood pressure) and metabolic study (triglycerides, total cholesterol, HDL-C, LDL-C, glucose, insulin, HOMA-IR, leptin, calcium, phosphorous, calcidiol, and PTH) were carried out in 236 adolescents diagnosed with severe obesity (BMI z-score > 3.0, 99th percentile), aged 10.2-15.8 years. The criteria of the US Endocrine Society were used for the definition of Vitamin D status.

RESULTS

Subjects with Vitamin D deficiency had significantly elevated values (p < 0.05) for BMI z-score, waist circumference, waist z-score, body fat percentage, fat mass index, systolic and diastolic blood pressure, total cholesterol, triglycerides, LDL-C, insulin, HOMA-IR, leptin, and PTH than subjects with normal Vitamin D status. There was a significant negative correlation (p < 0.05) of serum 25(OH)D levels with body fat percentage, FMI, systolic BP, total cholesterol, triglyceride, LDL-C, glucose, insulin, HOMA-IR, leptin, and PTH.

CONCLUSIONS

Low Vitamin D levels in adolescents with severe obesity were significantly associated with some cardiometabolic risk factors, including body mass index, waist circumference, fat mass index, high blood pressure, impaired lipid profile, and insulin resistance.

Prospect of Sodium-Glucose Co-transporter 2 Inhibitors Combined With Insulin for the Treatment of Type 2 Diabetes

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new family of antidiabetic drugs that reduce blood glucose independent of insulin. In this review, we present the advantages and adverse effects of SGLT2 inhibitors plus insulin therapy as a treatment regimen for patients with type 2 diabetes (T2D). Compared with placebo, SGLT2 inhibitors plus insulin therapy could significantly decrease fasting blood glucose and HbA1c, thereby reducing the daily required dose of insulin. A reduction in body weight and improvements in insulin resistance and β-cell function have also been widely reported with this therapy, and other potential advantages, including the reduction in blood pressure, adverse cardiovascular outcomes, and visceral adipose tissue volume, have been revealed. SGLT2 inhibitors cause a greater reduction than dipeptidyl peptidase-4 (DPP-4) inhibitors in body weight and the risk of cardiovascular disease. Furthermore, compared with glucagon-like peptide-1 (GLP-1) agonists, SGLT2 inhibitors reduce blood pressure, and heart failure. As this therapy is an oral preparation, an improvement in patient compliance is also achieved. Despite these advantages, however, combination therapy with SGLT2 inhibitors and insulin has several risks. Although no difference has been found in the incidence of hypoglycemic events and urinary tract infection between the administration of this combination and that of placebo, the risk of genital tract infections was reported to increase with the combination therapy. Additionally, bone adverse effects, euglycemic diabetic ketoacidosis, and volume depletion-and osmotic diuresis-related adverse effects have been observed. Altogether, we could conclude that SGLT2 inhibitors plus insulin therapy is an efficient treatment option for patients with T2D, especially those requiring high daily insulin doses and those with insulin resistance, obesity, and a high risk of cardiovascular events. However, careful monitoring of the adverse effects of this combination is also warranted.

Saroglitazar Deactivates the Hepatic LPS/TLR4 Signaling Pathway and Ameliorates Adipocyte Dysfunction in Rats with High-Fat Emulsion/LPS Model-Induced Non-alcoholic Steatohepatitis

The most epidemic liver disorder non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis and inflammation with hepatocellular damage. Recently, it is predictable to be the extensive cause for liver transplantation. The absence of an approved therapeutic agent for NASH is the reason for investigating saroglitazar (SAR) which showed promising effects as a dual PPAR-α/γ agonist in recent studies on NASH. Here, we aimed to investigate the effect of SAR on NASH induced in rats by the administration of high-fat emulsion (HFE) and small doses of lipopolysaccharides (LPS) for 5 weeks. Rats were divided into three groups: negative control group (saline and standard rodent chow), model group (HFE(10 ml/kg/day, oral gavage) + LPS(0.5 mg/kg/week, i.p)), and SAR-treated group (HFE(10 ml/kg/day, oral gavage) + LPS(0.5 mg/kg/week, i.p.) + SAR(4 mg/kg/day, oral gavage) starting at week 3.Treatment with SAR successfully ameliorated the damaging effects of HFE with LPS, by counteracting body weight gain and biochemically by normalization of liver function parameters activity, glucose, insulin, homeostasis model of assessment (HOMA-IR) score, lipid profile levels, and histopathological examination. Significant changes in adipokine levels were perceived, resulting in a significant decline in serum leptin and tumor necrosis factor-α (TNF-α) level concurrent with adiponectin normalization. The positive effects observed for SAR on NASH are due to the downregulation of the LPS/TLR4 pathway, as indicated by the suppression of hepatic Toll-like receptor 4 (TLR4), NF-κB, TNF-α, and transforming growth factor-β1 (TGF-β1) expression. In conclusion, this work verified that SAR ameliorates NASH through deactivation of the hepatic LPS/TLR4 pathway and inhibition of adipocyte dysfunction.

Smoking and other determinants of bone turnover

The balance between bone resorption and formation may be assessed by measurement of bone turnover markers (BTMs), like carboxyl-terminal cross-linked telopeptide of type 1 collagen (CTX-1) and procollagen type 1 amino-terminal propeptide (P1NP). Smoking has been shown to influence bone turnover and to reduce bone mass density (BMD), the exact mechanism for this is, however, not settled. In this post-hoc study including 406 subjects (mean age 51.9 years), we aimed to study the impact of smoking on bone turnover. Moreover, we wanted to assess the inter-correlation between substances regulating bone metabolism and BTMs, as well as tracking over time. BMD measurements and serum analyses of CTX-1, P1NP, osteoprotegerin (OPG), receptor activator of nuclear factor ĸB ligand (RANKL), Dickkopf-1 (DKK1), sclerostin, tumor necrosis factor-α (TNF-α), and leptin were performed. Repeated serum measurements were made in 195 subjects after four months. Adjustments were made for sex, age, body mass index (BMI), smoking status, insulin resistance, serum calcium, parathyroid hormone, 25-hydroxyvitamin D and creatinine. Smokers had higher levels of DKK1 and OPG, and lower levels of RANKL, as reflected in lower BTMs and BMD compared to non-smokers. There were strong and predominantly positive inter-correlations between BTMs and the other substances, and there was a high degree of tracking with Spearman’s rho from 0.72 to 0.92 (P < 0.001) between measurements four months apart. In conclusion, smokers exhibited higher levels of DKK1 and OPG and a lower bone turnover than did non-smokers. The strong inter-correlations between the serum parameters illustrate the coupling between bone resorption and formation and crosstalk between cells.

New Insights into Adipokines as Potential Biomarkers for Type-2 Diabetes Mellitus

A large number of studies have been focused on investigating serum biomarkers associated with risk or diagnosis of type-2 diabetes mellitus. In the last decade, promising studies have shown that circulating levels of adipokines could be used as a relevant biomarker for diabetes mellitus progression as well as therapeutic future targets. Here, we discuss the possible use of recently described adipokines, including apelin, omentin-1, resistin, FGF-21, neuregulin-4 and visfatin, as early biomarkers for diabetes. In addition, we also include recent findings of other well known adipokines such as leptin and adiponectin. In conclusion, further studies are needed to clarify the pathophysiological significance and clinical value of these biological factors as potential biomarkers in type-2 diabetes and related dysfunctions.

Serum leptin and homeostasis model assessment-IR as novel predictors of early liver fibrosis in chronic hepatitis B virus infection

BACKGROUND

The relationship between hepatitis B virus (HBV) infection, leptin and insulin resistance remains unclear. We hypothesised links between serum leptin and insulin resistance in non-diabetic patients with chronic viral hepatitis B infection and their relation to liver fibrosis.

METHODS

We recruited 190 untreated patients with chronic HBV infection and 72 healthy controls. Serum leptin, fasting glucose, insulin, liver function tests (LFTs), C-peptide and Homeostasis model assessment-IR (HOMA-IR) were measured/calculated by ELISA and standard techniques.

RESULTS

Serum leptin, C-peptide (both P < 0.001), HOMA-IR (P = 0.021) and several LFTs were increased in patients with chronic HBV-infection. In multivariate regression analysis, both HOMA-IR (P = 0.003) and leptin (P = 0.002) were significant independent predictors of HBV infection. There were significant positive correlations (P < 0.01) between leptin and HOMA-IR (r = 0.81), between serum leptin and METAVIR activity (r = 0.95), and between HOMA-IR and BMI (r = 0.75), fasting glucose (r = 0.005), and fasting insulin (r = 0.81). Several LFTs, glucose and insulin correlated modestly (r = 0.61-0.69, P < 0.05) with leptin.

CONCLUSION

Serum leptin may be related to the rate of fibrosis progression in nondiabetic patients with chronic HBV infection. Follow-up by serial measurement of serum leptin and HOMA-IR in non diabetic HBV-infected patients may be used as a non-invasive marker of early liver fibrosis.

Adiponectin, in contrast to leptin, is not associated with body mass index, waist circumference and HOMA-IR in subjects of a west-African population

Factors associated with plasma levels of adiponectin and leptin were studied in adult subjects without diabetes from Cotonou in Benin (West-Africa). Seventy (70) men and 45 women were included in the study. Anthropometric variables were measured and a venous blood sample was drawn from each subject, after an overnight fasting period, for measurement of plasma glucose, insulin, leptin, and adiponectin levels. HOMA-IR was determined to assess insulin resistance. Adiponectin and leptin levels were higher in women than in men (with adiponectin 18.48 ± 12.77 vs.7.8 ± 10.39 μg/mL, P < 0.0001, and leptin 30.77 ± 19.16 vs. 8.66 ± 8.24 ng/mL, P < 0.0001). Fasting insulin level and HOMA-IR were also higher in the females. Hyperleptinemia was observed in 66,96% of subjects and hypoadiponectinemia was present in 44.35% of subjects. In both men and women, leptin correlated with age (r = 0.2; P = 0.02), BMI (r = 0.572; P < 0.0001), waist circumference (r = 0.534; P < 0.0001), fasting insulin (r = 0.461; P < 0.001), and HOMA-IR (r = 0.430; P < 0.0001). No significant correlation was observed for adiponectin levels with these variables. Only in women, adiponectin was inversely correlated with fasting glucose (r = -0.423; P < 0.004). These data confirm previous descriptions of leptin but suggest that variations in factors determining serum adiponectin levels observed between ethnicities could also been seen between populations from the same ethnicity.

Leptin-induced basal Akt phosphorylation and its implication in exercise-mediated improvement of insulin sensitivity

Physical exercise is an efficient therapeutical tool in the management of insulin resistance (IR) and related metabolic diseases. Leptin, the well-known obesity hormone and the absence of which leads to IR, showed controversial effects on IR as research continues. Thus, in this study, a detailed investigation of the effect of leptin on exercise-mediated improvement of insulin sensitivity and its underlying mechanism was carried out. Using a rat model of chronic or acute swimming exercise training, we found that serum leptin increased 1 h after either acute exercise or the last session of chronic exercise, when impaired insulin action was observed in previous reports. However, chronic exercise reducd basal serum leptin levels and promoted insulin sensitivity compared with sedentary controls or rats subjected to one bout of aerobic exercise. Our animal results indicated the potential linkage between leptin and insulin sensitivity, which is further investigated in the skeletal muscle L6 cells. Leptin treatment in L6 cells promoted the basal levels of insulin signaling as well as glucose uptake, while blocking JAK2 signaling with either pharmacological intervention (JAK2 inhibitor AG490) or genetic manipulation (siRNA knockdown) decreased the basal levels of insulin signaling. Furthermore, leptin treatment inhibited insulin-stimulated insulin signaling and glucose uptake, while blocking JAK2 signaling restored leptin-attenuated insulin sensitivity. Taken together, our results demonstrated that reduced serum leptin, at least in part, contributes to exercise-mediated improvement of insulin sensitivity, indicating JAK2 as a potent therapeutical target of insulin resistance.

Effect modification by region in the associations of LEP G2548A and LEPR Q223R polymorphisms with statin-induced CK elevation

We investigated the associations of LEP G2548A and LEPR Q223R polymorphisms with statin-induced creatine kinase (CK) elevation among Chinese patients with hyperlipidemia. A total of587 enrolled individuals were treated with 20 mg/d oral simvastatin for 8 consecutive weeks. Genotyping of LEP G2548A and LEPR Q223R were conducted using PCR-RFLP. Multiple regression analyses showed that, in the Dongzhi region only, patients carrying the LEP AA genotype had a significantly greater increase in CK levels compared to those carrying the AG+GG genotypes after four weeks (P = 0.004) and eight weeks (P < 0.001) consecutive simvastatin treatment. Patients were further divided into three groups based on the tertiles of the CK distribution. Compared to subjects in the lowest tertile of CK elevation, the adjusted relative odds of having the AG+GG genotypes among subjects in the highest tertile was 0.5 (95% CI, 0.3 to 0.7) and 0.4 (95% CI, 0.2 to 0.6) after the fourth and eighth weeks, respectively. The interaction terms between the Beijing or Dongzhi region and the LEP GA+AA genotypes were marginally significant for CK elevation at the fourth week (P = 0.057) and significant for CK elevation at the eighth week (P = 0.002). The adverse effect of the LEP G2548A polymorphism on increasing CK levels may be dependent on the environmental milieu. It suggests that lifestyle interventions might offset the side effects of simvastatin therapy among those with genetic susceptibility. Further research is needed to identify specific individual-level factors for clinical practice that modify the effect of genotype.

Chronic hyper-leptinemia induces insulin signaling disruption in adipocytes: Implications of NOS2

Leptin, following its discovery, has developed a formidable interest in the scientific community to delineate its contribution towards overall metabolic homeostasis. Contradictory reports have been published on leptin administration effects on whole body insulin sensitivity. Following late reports, we surveyed human serum leptin levels along with other metabolic parameters including BMI and HOMA-IR. We found a positive correlation between leptin levels and insulin resistance parameters. Considering the presence of the long form of leptin receptor on adipocytes, we explored the effects of chronic physiological hyper-leptinemic exposure on adipocyte insulin sensitivity. Chronic leptin (50ng/ml) treatment in 3T3-L1 adipocytes decreased insulin-induced phosphorylation of nodal insulin signaling proteins along with reduced glucose uptake. Metabolic flux studies indicated mitochondrial dysfunction and reduced oxygen consumption rate. Leptin treatment also increased both cellular and mitochondrial superoxide levels concomitant to increased expression of nitric oxide synthase-2 (NOS2). Further, pharmacological depletion of NOS2 reversed leptin mediated effects on insulin signaling. In-vivo implantation of leptin osmotic pumps in C57BL/6 mice also decreased insulin responsiveness. Interestingly, these effects were lacking in NOS2 knockout strain. In conclusion, our studies put forward a potential link between leptin and adipocyte insulin responsiveness in an NOS2 dependent manner.

The role of bariatric surgery in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) affects between 25% and 33% of the population, is more common in obese individuals, and is the most common cause of chronic liver disease in the United States. However, despite rising prevalence, effective treatments remain limited. Areas covered: We performed a literature search across multiple databases (Pubmed, Medline, etc.) to identify significant original research and review articles to provide an up-to-date and concise overview of disease pathogenesis and diagnostic evaluation and to expand on available treatment options with a specific focus on the potential role of bariatric surgery. Here we provide the most comprehensive review of bariatric surgery for the management of NAFLD, noting benefits from different procedures and multiple reports showing improvements in steatosis, inflammation and fibrosis over the duration of follow-up. Expert commentary: The morbidity of NAFLD is significant as it may become the most common indication for liver transplantation within the next 5 years. In addition to known benefits of weight loss and diabetes resolution, bariatric surgery has the potential to halt and reverse disease progression and future controlled trials should be performed to further define its benefit in the treatment of NAFLD in morbidly obese patients.

Analysis of the association of leptin and adiponectin concentrations with metabolic syndrome in children: Results from the IDEFICS study

BACKGROUND AND AIMS

Adipokines may play a role in the pathogenesis of the metabolic syndrome (MetS) in children. We aimed to evaluate the association of leptin, adiponectin, and its ratio (L/A ratio) with the metabolic syndrome (MetS) in a subsample of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort.

METHODS AND RESULTS

Leptin, adiponectin and MetS parameters were measured in a subsample of 1253 children (3-9.9 years) participating to the IDEFICS study, grouped as: Non-OW (underweight/normal weight) and OW/Ob (overweight/obese). MetS was defined using the sex- and age-specific cut-offs based on the distribution of MetS components in the IDEFICS cohort. The prevalence of the MetS among OW/Ob was 24.8% and 27.1% in boys and girls respectively, whereas ≤2% among Non-OW. OW/Ob had significantly higher leptin and L/A ratio as compared to Non-OW. Significantly higher leptin was found in OW/Ob with MetS as compared with OW/Ob without MetS. Significantly lower adiponectin was observed only in OW/Ob girls as compared to Non-OW. A 1SD increase in leptin and L/A ratio z-scores or a 1SD decrease in adiponectin z-score were significantly associated with higher risk of MetS. After adjustment for BMI or body fat mass (BFM) the association remained significant only for leptin.

CONCLUSION

We showed that in European children, higher leptin concentration is associated with MetS, even after adjusting for BMI or BFM, confirming an early role of leptin in MetS, while the association of adiponectin with MetS seems be mediated by body fat in this age range.

Sleep-disordered breathing, systemic adipokine secretion, and metabolic dysregulation in overweight and obese children and adolescents

OBJECTIVE

Obstructive sleep apnea (OSA) is common among overweight and obese children, and it is an independent risk factor for developing metabolic syndrome. However, the mechanisms linking OSA and metabolic syndrome are still unclear, but a role for adipose tissue dysfunction caused by intermittent hypoxia has been suggested. Therefore, the goal of this study was to investigate the relationship between OSA and systemic adipokine concentrations in overweight and obese children.

METHODS

We included 164 overweight and obese children in a tertiary center and distributed them in groups based on their obstructive apnea-hypopnea index (111 controls, 28 mild OSA, 25 moderate-to-severe OSA). All subjects underwent polysomnography and a blood sample was taken to determine leptin, adiponectin, tumor necrosis factor alpha, and interleukin-6 levels.

RESULTS

No significant differences were found in adipokine levels between subjects with or without OSA. Leptin correlated with oxygen desaturation index (r = -0.17, p = 0.03), adiponectin correlated with mean oxygen saturation (r = 0.24, p = 0.002) and with the percentage of sleep time with an oxygen saturation >95% (r = 0.25, p = 0.001). However, these associations did not persist after correction for adiposity. No correlations between interleukin-6 and tumor necrosis factor alpha, and OSA severity were found.

CONCLUSION

These results suggest that serum adipokine levels are mostly dependent on central obesity, while they are not influenced by OSA in an obese pediatric population.

Estimating relative risk of a log-transformed exposure measured in pools

Pooling biospecimens prior to performing laboratory assays is a useful tool to reduce costs, achieve minimum volume requirements and mitigate assay measurement error. When estimating the risk of a continuous, pooled exposure on a binary outcome, specialized statistical techniques are required. Current methods include a regression calibration approach, where the expectation of the individual-level exposure is calculated by adjusting the observed pooled measurement with additional covariate data. While this method employs a linear regression calibration model, we propose an alternative model that can accommodate log-linear relationships between the exposure and predictive covariates. The proposed model permits direct estimation of the relative risk associated with a log-transformation of an exposure measured in pools. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Circulating ferritin concentrations are differentially associated with serum adipokine concentrations in Japanese men and premenopausal women

PURPOSE

Increased iron storage, as measured by circulating ferritin, has been linked to an increased risk of various diseases including diabetes. We examined the association of circulating ferritin with serum adiponectin, leptin, resistin, plasminogen activator inhibitor-1 (PAI-1), and visfatin levels.

METHODS

We conducted a cross-sectional study among 429 Japanese employees (284 men and 145 premenopausal women, mean age: 42.5 ± 10.5 years). Serum adipokines were measured using Luminex suspension bead-based multiplexed array, and serum ferritin was determined using a chemiluminescence immunoassay. Multivariable regression analysis was performed to calculate mean concentrations of adipokine according to the tertile of ferritin concentrations with adjustment for potential confounders.

RESULTS

Leptin and visfatin concentrations increased with increasing ferritin concentrations in men after multivariable adjustment of physical activity, smoking, alcohol use, and body mass index (P for trend = 0.02 and 0.01 for leptin and visfatin, respectively). Serum ferritin concentrations were inversely and significantly associated with adiponectin in women (P for trend = 0.01). Resistin and PAI-1 were not appreciably associated with ferritin concentration.

CONCLUSIONS

Increased iron storage may be associated with higher circulating concentrations of leptin and visfatin in men and with lower concentrations of adiponectin in women.

Cardiometabolic Health Among Cancer Survivors: A 13-Week Pilot Study of a Combined Aerobic and Resistance Training Program

PURPOSE/OBJECTIVES

To explore the feasibility of combined aerobic and resistance training (CART) as a safe method of improving cardiometabolic health among cancer survivors.
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DESIGN

Descriptive and longitudinal pilot study for exercise intervention.
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SETTING

University campus in Los Angeles, California.
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SAMPLE

A multiethnic population of cancer survivors (N = 11) was recruited by convenience sampling and physician referral. 
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METHODS

Consenting participants were prescribed CART for one hour per day, three days per week for 13 weeks.
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MAIN RESEARCH VARIABLES

Components of cardiometabolic health were measured, including resting heart rate (HRrest), blood pressure, body mass index, waist circumference, body fat percentage, and android fat percentage at baseline and after 13 weeks of training. Fasting blood glucose, insulin, adiponectin, leptin, tumor necrosis factor alpha, and C-reactive protein (CRP) also were assessed at baseline and after 13 weeks of training.
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FINDINGS

More than half of the participants reported living with at least two other chronic diseases or conditions in addition to a cancer diagnosis. Five of six African American and Hispanic participants reported the presence of at least two risk factors for metabolic syndrome, compared to one of five Caucasian participants. After 13 weeks of training, participants experienced an average decrease in waist circumference. Decrease in waist circumference was associated with a decrease in CRP. A relationship also was suggested between number of exercise sessions attended and improvement in HRrest. 
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CONCLUSIONS

A CART intervention among cancer survivors should continue to be explored in a larger sample to establish efficacy and effectiveness at improving cardiometabolic health. Because of the higher risk of comorbidity among cancer survivors in comparison to cancer-free adults, improving cardiometabolic health is as important as monitoring cancer recurrence. A need exists for increased attention to the post-treatment cardiometabolic health of cancer survivors and also for examining potential cardiometabolic health disparities among non-Caucasian cancer survivors.
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IMPLICATIONS FOR NURSING

CART may be a plausible alternative to reduce the risk of metabolic syndrome and improve cardiometabolic health among cancer survivors. Additional studies that continue to explore the efficacy and effectiveness of CART may provide more information to help nurses and physicians determine whether the cancer survivorship care plan should include an exercise-based alternative to intervene on cardiometabolic health.

Protein Biomarkers for Insulin Resistance and Type 2 Diabetes Risk in Two Large Community Cohorts

Insulin resistance (IR) is a precursor of type 2 diabetes (T2D), and improved risk prediction and understanding of the pathogenesis are needed. We used a novel high-throughput 92-protein assay to identify circulating biomarkers for HOMA of IR in two cohorts of community residents without diabetes (n = 1,367) (mean age 73 ± 3.6 years). Adjusted linear regression identified cathepsin D and confirmed six proteins (leptin, renin, interleukin-1 receptor antagonist [IL-1ra], hepatocyte growth factor, fatty acid-binding protein 4, and tissue plasminogen activator [t-PA]) as IR biomarkers. Mendelian randomization analysis indicated a positive causal effect of IR on t-PA concentrations. Two biomarkers, IL-1ra (hazard ratio [HR] 1.28, 95% CI 1.03-1.59) and t-PA (HR 1.30, 1.02-1.65) were associated with incident T2D, and t-PA predicted 5-year transition to hyperglycemia (odds ratio 1.30, 95% CI 1.02-1.65). Additional adjustment for fasting glucose rendered both coefficients insignificant and revealed an association between renin and T2D (HR 0.79, 0.62-0.99). LASSO regression suggested a risk model including IL-1ra, t-PA, and the Framingham Offspring Study T2D score, but prediction improvement was nonsignificant (difference in C-index 0.02, 95% CI -0.08 to 0.12) over the T2D score only. In conclusion, proteomic blood profiling indicated cathepsin D as a new IR biomarker and suggested a causal effect of IR on t-PA.

Relating Phthalate and BPA Exposure to Metabolism in Peripubescence: The Role of Exposure Timing, Sex, and Puberty

CONTEXT

Exposure to endocrine-disrupting chemicals during development may play a role in the increasing prevalence of metabolic syndrome and type 2 diabetes among children and adolescents by interfering with metabolic homeostasis.

OBJECTIVE

To explore associations between in utero and peripubertal urinary phthalate metabolite and bisphenol A (BPA) concentrations and markers of peripubertal metabolic homeostasis.

DESIGN

Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT): a longitudinal cohort study of pregnant women in Mexico City and their offspring.

SETTING

Public maternity hospitals in Mexico City.

PATIENTS OR OTHER PARTICIPANTS

Women recruited during pregnancy; offspring recruited for follow-up at age 8-14 years (n = 250).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Fasting serum c-peptide, IGF-1, leptin, and glucose concentrations among children at follow-up; calculated measures of insulin secretion and insulin resistance.

RESULTS

Phthalate metabolites and BPA were associated with metabolism biomarkers at age 8-14 years in patterns that varied by sex, pubertal status, and exposure timing. For example, in utero monoethyl phthalate was associated with lower insulin secretion among pubertal boys (P = .02) and higher leptin among girls (P = .04). In utero di-2-ethylhexyl phthlate was associated with higher IGF-1 among pubertal girls; peripubertal di-2-ethylhexyl phthlate was associated with higher IGF-1, insulin secretion, and resistance among prepubertal girls. In contrast, peripubertal dibutyl phthalate, monobenzyl phthalate, and mono-3-carboxypropyl phthalate were associated with lower IGF-1 among pubertal boys. Peripubertal BPA was associated with higher leptin in boys (P = .01).

CONCLUSIONS

Considering the long-term health effects related to metabolic syndrome, additional research on exposure and metabolic outcomes across developmental periods and early adulthood is needed.

Intermuscular adipose tissue is associated with monocyte chemoattractant protein-1, independent of visceral adipose tissue

OBJECTIVES

Emerging evidence suggests that intermuscular adipose tissue is a risk factor for insulin resistance, but the underlying mechanism still remains unclear. We investigated whether the levels of leptin, adiponectin, and monocyte chemoattractant protein-1 are associated with intermuscular adipose tissue in obese subjects.

DESIGN AND METHODS

A cross-sectional study was performed on 77 obese Korean women. Areas of visceral adipose tissue, subcutaneous adipose tissue, and intermuscular adipose tissue were measured by computed tomography scan, and serum concentrations of adipokines were measured by enzyme-linked immunosorbent assays. Correlation between the levels of adipokines and the fat areas was assessed using Pearson correlation and covariate-adjusted multivariable regression.

RESULTS

Leptin was positively correlated with subcutaneous adipose tissue (r=0.452, P<0.001), fasting insulin (r=0.403, P<0.001), and homeostasis model assessment of insulin resistance (r=0.360, P=0.001), whereas monocyte chemoattractant protein-1 was positively correlated with intermuscular adipose tissue (r=0.483, P<0.001). After adjustment for age, height, and other body composition metrics, leptin was still related to subcutaneous adipose tissue (β=0.390, P=0.001). Monocyte chemoattractant protein-1 was associated with intermuscular adipose tissue (β=0.433, P=0.001) after adjustment for visceral adipose tissue.

CONCLUSIONS

Intermuscular adipose tissue was correlated with monocyte chemoattractant protein-1, suggesting its role in the development of insulin resistance.

Metabolic changes in serum metabolome in response to a meal

PURPOSE

The change in serum metabolic response from fasting state to postprandial state provides novel insights into the impact of a single meal on human metabolism. Therefore, this study explored changes in serum metabolite profile after a single meal.

METHODS

Nineteen healthy postmenopausal women with normal glucose tolerance participated in the study. They received a meal consisting of refined wheat bread (50 g carbohydrates, 9 g protein, 4.2 g fat and 2.7 g dietary fibre), 40 g cucumber and 300 mL noncaloric orange drink. Blood samples were collected at fasting and five postprandial time points. Metabolic profile was measured by nuclear magnetic resonance and targeted liquid chromatography-mass spectrometry. Changes over time were assessed with multivariate models and ANOVA, with baseline as control.

RESULTS

The metabolomic analyses demonstrated alterations in phospholipids, amino acids and their breakdown products, glycolytic products, acylcarnitines and ketone bodies after a single meal. More specifically, phosphatidylcholines, lysophosphatidylcholines and citrate displayed an overall declining pattern, while leucine, isoleucine, methionine and succinate increased initially but declined thereafter. A sharp decline in acylcarnitines and ketone bodies and increase in glycolytic products postprandially suggest a switch in the body's energy source from β-oxidation to glycolysis. Moreover, individuals with relatively high postprandial insulin responses generated a higher postprandial leucine responses compared to participants with lower insulin responses.

CONCLUSIONS

The study demonstrated complex changes from catabolic to anabolic metabolism after a meal and indicated that the extent of postprandial responses is different between individuals with high and low insulin response.

Sex-Specific Mediating Role of Insulin Resistance and Inflammation in the Effect of Adiposity on Blood Pressure of Prepubertal Children

Objective

To evaluate the association between obesity indices and blood pressure (BP) at 4 years of age, in each sex, and to quantify to which extent this association is mediated by inflammation and insulin resistance (IR).

Materials and Methods

We studied 1250 4-year-old children selected from the population-based birth cohort Generation XXI. Associations between body mass index (BMI) z-score and waist-to-height ratio (WHtR), office BP, inflammation (high sensitivity C-reactive protein) and IR (HOMA-IR index) were assessed. Path Analysis, a modified multivariate regression approach, was applied to test causal models and quantify direct and indirect effects of predictors of systolic (SBP) and diastolic BP (DBP).

Results

SBP and DBP increased significantly with BMI and WHtR in both sexes. There was a strong direct association (explaining 74.1-93.2% of the total association) of both measures of adiposity with SBP, in both sexes. This association was additionally indirectly mediated by IR, particularly regarding WHtR (20.5% in girls and 9.4% in boys). Mediation by inflammation did not reach statistical significance in either sex. Regarding DBP, the direct effect of adiposity was strong (>95% for BMI and WHtR in boys) and the mediation by IR was much smaller in boys than in girls.

Discussion

The direct association between adiposity and BP in healthy 4-year-old children is strong and IR plays an important mediating role. The strength of effects of IR and inflammation suggests sex differences in the complex interplay between BP, adiposity and inflammation.

Association of dietary patterns with serum adipokines among Japanese: a cross-sectional study

BACKGROUND

Diet may influence disease risk by modulating adipokines. Although some foods and nutrients have been linked to circulating adipokine levels, little is known about the role of dietary patterns on adipokines. We investigated the association between major dietary patterns and circulating levels of adiponectin, leptin, resistin, visfatin, and plasminogen activator inhibitor-1 (PAI-1) in a working population.

METHODS

The subjects were 509 employees (296 men and 213 women), aged 20 to 65 years, of two municipal offices. Serum adipokines were measured using a Luminex suspension bead-based multiplexed array. Dietary patterns were derived by using principal component analysis of the consumption of 52 food and beverage items, which were ascertained by a validated diet history questionnaire. Multiple regression analysis was performed to assess the association between dietary pattern scores and adipokine concentrations, with adjustment for potential confounders.

RESULTS

Three major dietary patterns were extracted: a Japanese, a Westernized breakfast, and a meat food patterns. Of these, we found significant, inverse associations of the Westernized breakfast pattern, which was characterized by higher intake of confectioneries, bread, and milk and yogurt but lower intake of alcoholic beverages and rice, with serum leptin and PAI-1 concentrations in a fully adjusted model (P for trend = 0.04 for both leptin and PAI-1). The other adipokines were not significantly associated with any dietary pattern.

CONCLUSION

The Westernized breakfast dietary pattern may be associated with lower circulating levels of leptin and PAI-1.