Leptin, adiposity, and mortality: results from the National Health and Nutrition Examination Survey III, 1988 to 1994

Proteomic Mediators of Overall Cardiovascular Health on All-Cause Mortality

Measures of cardiovascular health (CVH) assessed by a combination of behavioral and biological factors has shown protective associations with all-cause mortality. The mechanisms underlying these associations have not been fully elucidated. In this study, we characterized the plasma proteomics profile of CVH and tested whether specific proteins mediated the associations between CVH and all-cause mortality in participants of the InCHIANTI study. Of the 1301 proteins tested, 92 proteins were associated with CVH (22 positively, 70 negatively). Proteins most strongly associated with CVH included leptin (LEP), fatty acid binding protein 3 (FABP3), Angiopoietin-2 (ANGPT2), and growth-differential factor 15 (GDF15). Of the 92 CVH-associated proteins, 33 proteins significantly mediated the associations between CVH and all-cause mortality, with percent mediation ranging from 5 to 30%. The most significant mediating proteins were GDF15 and insulin-like growth factor 2 (IGFBP2). Proteins associated with better CVH were enriched for proteins that reflect the suppression of the complement coagulation and GH/IGF pathways.

Leptin and advanced glycation end products receptor (RAGE) in tuberculosis patients

Introduction

The pathogenesis of consumptive syndrome of tuberculosis (TB) is largely unknown. Leptin concentrations may be high because of the host’s inflammatory response, contributing to weight loss in patients with TB. The receptor for advanced glycation end products (RAGE) is also associated with weight loss in patients with TB and is related to enhanced mortality. The objective of this study was to evaluate the association between leptin and AGE/RAGE.

Methods

Case-control study. Leptin, AGE (carboxymethyl lysine, CML) and soluble RAGE (sRAGE) were measured from blood samples by ELISA.

Results

We included in the study 34 patients with TB and 34 controls. We found an inverse correlation between serum leptin levels and sRAGE, only in cases (r = -0.609, p < 0.0001). sRAGE levels were lower in patients with TB who died as compared with patients who survive (21.90 ± 4.24 pg/mL vs 66.14 ± 29.49 pg/mL; p = 0.045). Leptin levels were higher in patients with TB who died as compared with patients who survive (14.11 [7.48–14.11] ng/mL vs 3.08 [0.54–6.34] ng/mL; p = 0.028).

Conclusions

We identified lower sRAGE levels and higher leptin levels in patients with TB who died as compared with patients who survive. In addition, an inverse and significant correlation between serum leptin and sRAGE levels was demonstrated. Future studies, with a larger sample size and in different settings, including not only hospitalized patients, are needed to confirm these findings.

Measurement of a Surrogate Biomarker for Arginine Vasopressin Secretion in Association with Physiometric and Molecular Biomarkers of Aging

A number of physiological changes are known to occur with aging, including increased fat mass, increased insulin resistance, and changes in the levels of circulating biomarkers such as lipids, growth factors, and hormones. Here, we present protocols for physiometric assessments, as well as measurements of circulating biomarkers of hormonal and growth factor function in individuals over the age range of 18-52 years. We also test for potential gender differences in the outcome measures.

Longitudinal Increases in Adiposity Contribute to Worsening Adipokine Profile over Time in Mexican Americans

OBJECTIVE

Limited studies have assessed the relationship between longitudinal changes in adiposity and changes in multiple adipokines over time. This study examined changes in BMI, total body fat, and trunk fat associated with changes in 16 circulating adipokines in Mexican Americans at risk for type 2 diabetes.

METHODS

Participants included 1,213 individuals with cross-sectional data and a subset of 368 individuals with follow-up measures (mean 4.6 ± 1.5 years from baseline). Joint multivariate associations between 3 adiposity measures and 16 adipokines were assessed by canonical correlation analysis.

RESULTS

Longitudinal increases in adiposity were most strongly associated with increasing leptin, C-reactive protein (CRP), and interleukin 1 receptor antagonist (IL-1Ra) and decreasing adiponectin and secreted frizzled protein 5 (SFRP5) over time. Participants with BMI ≥ 30 kg/m² at baseline had greater increases in leptin, CRP, IL-1Ra, and interleukin 6 (IL-6) and greater decreases in adiponectin and SFRP5, associated with increasing adiposity over follow-up, than those with BMI < 30 kg/m² . Associations between adiposity and adipokines were most accounted for by leptin; adjustment for leptin greatly reduced the magnitude of all associations between adiposity and remaining adipokines.

CONCLUSIONS

Increasing adiposity contributes to a worsening imbalance of pro- and anti-inflammatory adipokines over time, in which leptin may have an important role as a key mediator of metabolic disease risk in Mexican Americans.

Translating the biology of adipokines in atherosclerosis and cardiovascular diseases: Gaps and open questions

AIM

Critically discuss the available data, to identify the current gaps and to provide key concepts that will help clinicians in translating the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

DATA SYNTHESIS

Adipose tissue is nowadays recognized as an active endocrine organ, a function related to the ability to secrete adipokines (such as leptin and adiponectin) and pro-inflammatory cytokines (tumor necrosis factor alpha and resistin). Studies in vitro and in animal models have observed that obesity status presents a chronic low-grade inflammation as the consequence of the immune cells infiltrating the adipose tissue as well as adipocytes. This inflammatory signature is often related to the presence of cardiovascular diseases, including atherosclerosis and thrombosis. These links are less clear in humans, where the role of adipokines as prognostic marker and/or player in cardiovascular diseases is not as clear as that observed in experimental models. Moreover, plasma adipokine levels might reflect a condition of adipokine-resistance in which adipokine redundancy occurs. The investigation of the cardio-metabolic phenotype of carriers of single nucleotide polymorphisms affecting the levels or function of a specific adipokine might help determine their relevance in humans. Thus, the aim of the present review is to critically discuss the available data, identify the current gaps and provide key concepts that will help clinicians translate the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

Impact of the body mass index on perioperative immunological disturbances in patients with hip and knee arthroplasty

BACKGROUND

Obesity increases the risk for knee and hip joint implantation and negatively contributes to wound healing. In this study, in 52 patients undergoing hip and knee arthroplasty the amount of peripheral immune effector cells pre- and post-operative, as well as the expression of certain soluble factors affecting the functions of immune effector cells were investigated.

METHODS

The peripheral immune cells and the expression of the soluble factors were determined by flow cytometry and correlated to each other in dependency of the BMI, the sex, and the kind of arthroplasty.

RESULTS

The pre-operative amounts of peripheral NK cells and cytotoxic T cells significantly decreased with increasing BMI. Furthermore, the expression of the immunomodulatory adipokine leptin nicely correlated to the BMI. These effects were stronger in males than in females. Furthermore, the correlation of the activation marker sTNF-R and peripheral T cells strongly decreased with increasing BMI. While IL-6, CD40L, and MPO were significantly induced after surgery, there were no correlations to the BMI.

CONCLUSIONS

The known wound-healing problems in obese patients and the osteoarthritis per se can be linked to the BMI. While obese patients exerted reduced peripheral NK cells and cytotoxic T cells (CTLs), IL-6 showed no involvement. However, the adipokine leptin strongly increased with the BMI strengthening its role as immunomodulatory molecule negatively interfering the functions of immune effector cells.

Adiponectin, Leptin and Inflammatory Markers in HIV-associated Metabolic Syndrome in Children and Adolescents

BACKGROUND

Metabolic syndrome (MetS) is more common in HIV-infected adults and children than in the general population. Adipocytokines and inflammatory markers may contribute to the pathophysiology of this condition and could be useful indices for monitoring MetS. The objective of this study was to provide information on the prevalence of MetS and investigate the role of adipocytokines and other biomarkers in this syndrome in HIV-infected pediatric patients.

METHODS

A cross-sectional study was conducted between October 2013 and March 2014 in the outpatient clinics of 2 tertiary pediatric referral hospitals. Fifty-four HIV-infected children and adolescents were included. MetS was defined according to the International Diabetes Federation and modified National Cholesterol Education Program Adult Treatment Panel III criteria. Measurements included anthropometry, waist circumference, blood pressure, fasting lipids, glucose and insulin, adiponectin, leptin, interleukin-6, vitamin D and C-reactive protein and clinical lipodystrophy assessment.

RESULTS

Among the total, 3.7% of patients met the International Diabetes Federation criteria for MetS and 7.4% met the National Cholesterol Education Program Adult Treatment Panel III criteria. C-reactive protein and leptin levels were significantly higher and adiponectin level significantly lower in patients with MetS, regardless of the criteria used. Insulin resistance was observed in 40.7% of patients; abnormal quantitative insulin sensitivity check index values were found in 88.9%. Eighteen patients (33.3%) had vitamin D deficiency.

CONCLUSIONS

The prevalence of MetS was similar to that observed in larger cohorts of HIV-infected patients in our setting. Adipocytokine dysregulation seems to be related to MetS in HIV-infected children. A high percentage of patients showed insulin resistance, which should be strictly monitored.

Sarcopenia, sarcopenic obesity and inflammation: Results from the 1999-2004 National Health and Nutrition Examination Survey

BACKGROUND

The Foundation for the National Institutes of Health Sarcopenia Project validated cutpoints for appendicular lean mass (ALM) to identify individuals at risk for functional impairment. Recognizing possible underlying mechanisms between adipose tissue and muscle, we sought to apply the recent definitions and determine the relationship with markers of glucose homeostasis and inflammation in individuals with sarcopenia and sarcopenic obesity.

METHODS

The National Health and Nutrition Examination Surveys 1999-2004 were used to identify 4984 adults aged ≥60 years with DEXA measures. Sarcopenia was defined using ALM (men<19.75 kg, women<15.02 kg) and ALM adjusted for body mass index (BMI; men<0.789 kg/m², women<0.512 kg/m²). Sarcopenic obesity was defined as subjects fulfilling the criteria for sarcopenia and obesity by body fat (men ≥25%, women ≥35%). We assessed the association between ALM and ALM:BMI with inflammatory and markers of glucose homeostasis, both as continuous variables but also classifying as having sarcopenic obesity or not after adjusting for confounding variables including pro-inflammatory chronic diseases such as diabetes and cancer.

RESULTS

Mean age was 71.1 years (56.5%) females. Prevalence of sarcopenia and sarcopenic obesity were (ALM definition: 29.9 and 24.4%; ALM:BMI definition: 23.0 and 22.7%). There were significant associations with ALM and ln C-reactive protein (β = 0.0287; p = 0.001), fibrinogen (β = 0.519; p < 0.001), and HOMA-IR (β = 0.359; p < 0.001). Using ALM:BMI, significant associations were observed with ln CRP (β = -2.58; p = 0.001), fibrinogen (β = -124.2; p < 0.001), and HOMA-IR (β = -6.63; p < 0.001). Sarcopenic obesity using the ALM:BMI definition demonstrated significant associations with CRP (β = 0.422; p < 0.001), fibrinogen (β = 22.5; p < 0.001), but not HOMA-IR (β = 1.19; p = 0.13). Strong associations with seen with increased levels of fibrinogen and CRP with sarcopenic obesity (ALM:BMI definition) that persisted after adjusting for diabetes and cancer.

CONCLUSIONS

Biologically plausible associations exist between ALM:BMI and inflammation and HOMA-IR that were not observed when using ALM alone. Future study should validate each of these definitions to prevent disparate results from being determined.

The FTO gene is associated with a paradoxically favorable cardiometabolic risk profile in frail, obese older adults

OBJECTIVE

Fat mass and obesity-associated (FTO) gene polymorphisms have been reported to be associated with differences in BMI, obesity, and type 2 diabetes. However, previous studies have been predominantly conducted in younger individuals across a spectrum of body weights, whereas little information is available on the older population. We examined the association of FTO gene polymorphisms with cardiometabolic risks among adults who were both obese (BMI≥30 kg/m) and older (age≥65 years).

METHODS

A total of 165 frail, obese older adults were genotyped for FTO (rs9939609 and rs8050136) single nucleotide polymorphisms and studied for associations with body weight and body composition, components and prevalence of the metabolic syndrome, insulin response to an oral glucose tolerance test, and levels of adipocytokines (e.g. leptin) and vitamin D.

RESULTS

Carriers of the A allele (CA/AA) of the FTO single nucleotide polymorphism rs8050136 had lower body weight, BMI, body fat, and trunk fat than those without the A allele (CC genotype; all P's<0.05). Moreover, genotype CA/AA was associated with lower levels of triglycerides and higher levels of high-density lipoprotein-cholesterol and carriers of this genotype showed a trend toward a lower waist circumference, resulting in a lower prevalence of metabolic syndrome than in CC genotype carriers. The insulin area under the curve during the oral glucose tolerance test was lower for genotype CA/AA. Despite the lower insulin levels, the glucose area under the curve was unchanged, resulting in a higher insulin sensitivity index. Leptin levels were also lower and adiponectin and 25-hydroxyvitamin levels tended to be higher for genotype CA/AA than for genotype CC. No differences were observed for rs9939609.

CONCLUSION

Unlike the results from studies in younger individuals, the risk A allele may confer a favorable cardiometabolic risk profile in obese older adults, suggesting selective survival of obese adults into old age. If confirmed in a larger sample of surviving obese older adults, these findings may have implications in the clinical approach to obesity in this population.