Significance of leptin and high-molecular weight adiponectin in the general population of Japanese male adolescents

Elevated adiponectin but varied response in circulating leptin levels to falciparum malaria in type 2 diabetics and non-diabetic controls

Background

To investigate effects of falciparum malaria on circulating levels of leptin and adiponectin in type 2 diabetes mellitus (T2DM) and non-diabetic controls in relation to measures of adiposity.

Methods

Levels of leptin and adiponectin were measured in 100 type 2 diabetics and 100 age-matched controls before and during falciparum malaria in a 2-year prospective study. Also, waist circumference (WC), weight, height and hip circumference were measured. Body mass index (BMI) and waist-to-hip ratio (WHR) were computed.

Results

At baseline, diabetics had significantly (p < 0.05) higher WC and BMI but lower WHR, leptin and adiponectin levels. Baseline leptin correlated positively with WC (r = 0.633; p < 0.001) and BMI (r = 0.63; p < 0.001) in diabetics but only BMI (0.562; p < 0.001) in non-diabetic controls. Baseline leptin and adiponectin correlated positively (r = 0.249; p = 0.029) in non-diabetic respondents only. Adiponectin correlated negatively with WC (r = −0.58; p = 0.006) in diabetic males only. During malaria, mean levels of leptin and adiponectin were comparable (p > 0.05) between diabetics and controls. However, compared to baseline levels, significant (p < 0.001) elevation of adiponectin was found in both study groups. In respect of leptin, significant (p < 0.001) rise but decline was observed in diabetics and controls respectively. Malaria-induced leptin correlated negatively with adiponectin (r = −0.694; p < 0.001) in non-diabetic controls only.

Conclusion

Diabetics and controls exhibited increased adiponectin levels due to falciparum malaria but differed in response in terms of leptin levels.

Random measurements of adiponectin and IL-6 may not be indicative of the 24-h profile in critically ill patients

CONTEXT

The anti-inflammatory role of adiponectin has prompted interest in a potential role in acute inflammatory conditions associated with critical illness. It is unclear whether a random adiponectin measurement adequately reflects the 24-h profile in critically ill patients.

OBJECTIVE

To assess the temporal profile of total and high molecular weight (HMW) adiponectin and interleukin-6 (IL-6) in 15 critically ill patients.

DESIGN

A prospective, observational study.

SETTING

Level II intensive care unit in a metropolitan hospital.

PATIENTS OR OTHER PARTICIPANTS

Fifteen critically ill patients expected to stay in the ICU for longer than 48 h were eligible for enrolment.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Serial, hourly measurements of total and HMW adiponectin and IL-6.

RESULTS

Over a 24-h period, total and HMW adiponectin display considerable within-patient variability (coefficient of variation 34% and 87% respectively) and show no trend over time. Averaging 2 or 3 continuous measures reduced within-patient variability of both total and HMW adiponectin by up to 50% compared to one measure. There was a negative correlation between serum glucose and adiponectin (total P = 0·016, HMW P = 0·039). No relationship existed between adiponectin and IL-6 (total P = 0·62, HMW P = 0·35).

CONCLUSIONS

Marked within-patient, hourly variability in total and HMW adiponectin is evident in critically ill patients. A random measurement may not be reflective of the 24-h profile in these patients. A negative correlation exists between adiponectin and blood glucose levels and a positive correlation between adiponectin and oxygen saturation. No clear relationship exists between adiponectin and IL-6.

The concurrent validity between leptin, BMI and skin folds during pregnancy and the year after

Background:

From a public health perspective it is important to know which of the currently used methods to estimate changes in maternal body fat during pregnancy and the year thereafter is the most adequate.

Objectives:

To evaluate the concurrent validity between leptin and surrogates of fat measures: body mass index (BMI) and the sum of four skin folds.

Design:

Data from the New Life(style) intervention study were analysed as a cohort study.

Setting:

Midwife practices in The Netherlands.

Population:

Healthy pregnant nulliparous women.

Methods:

Anthropometric measurements were done and blood was collected at 15, 25 and 35 weeks of pregnancy and at 6, 26 and 52 weeks after delivery. Data were used if at least 4 out of the 6 measurements were available, leaving 87 women in the analyses. Spearman's correlation coefficients between leptin and BMI and between leptin and the sum of skin folds were calculated for each time point and for the changes between the time points.

Results:

Correlations between leptin and BMI varied from 0.69 to 0.81. Correlations between leptin and the sum of skin folds were comparable, varying between 0.65 and 0.81.

Correlations between changes in leptin and changes in BMI and the sum of skin folds, respectively, were much lower compared with cross-sectional correlations.

Conclusion:

Because of the high correlation among the three methods and because of the overlapping intervals, all methods seem to be equally adequate to estimate changes in maternal body fat during pregnancy and the year thereafter.

Adiponectin multimers, body weight and markers of cardiovascular risk in adolescence: Northern Ireland Young Hearts Project

BACKGROUND

Research examining the relationship between adiponectin (AN) isoforms, body weight and cardiovascular (CV) risk factors is limited, particularly in younger populations.

OBJECTIVES

To investigate the inter-relationships between AN isoforms and CV risk factors, and their dependence on body weight status, in adolescents.

DESIGN

Blood samples from 92 obese, 92 overweight and 92 normal weight age- and sex-matched adolescents were analysed for traditional cardiovascular disease (CVD) risk biomarkers and also total, high molecular weight (HMW), medium and low molecular weight (LMW) AN.

RESULTS

A significant inverse association was observed between total and HMW AN and waist-hip ratio (P=0.015, P=0.006, respectively), triglycerides (P=0.003, P=0.003, respectively) and systolic blood pressure (P=0.012, P=0.024, respectively) and a significant positive association with high-density lipoprotein (P<0.001, P<0.001, respectively) in multi-adjusted analyses. There was no evidence of a relationship between multimeric AN and high-sensitivity C-reactive protein. There was also little evidence of a relationship between LMW AN and CVD risk factors. There was a strong, body mass index (BMI)-independent, association between AN, CVD biomarkers and the hypertriglyceridemic waist phenotype.

CONCLUSION

Prominent, BMI-independent associations between total and HMW AN, but not LMW AN, and CVD risk factors were already evident in this young population. This research in adolescents supports the contention that AN subfractions may have different biological actions. These associations in apparently healthy adolescents suggest an important role for AN and its subfractions in the pathogenesis of metabolic syndrome traits and indicate that the potential for total or HMW AN to act as early universal biomarkers of CV risk warrants further study.

The metabolic syndrome in critically ill patients

Metabolic support in intensive care is a rapidly evolving field with new information being gathered almost on a daily basis. In endocrine practice, over the last 20 years, researchers have focussed on a new entity, termed the "metabolic syndrome". This describes the constellation of abnormalities which include central adiposity, insulin resistance and inflammation. All of these predispose the individual to a greater risk of cardiovascular events. Of interest is the observation that some of the metabolic abnormalities in sepsis and multiple organ dysfunction syndrome of critical illness share several common features with that of the metabolic syndrome. In this chapter we describe the features of the metabolic syndrome as is understood in endocrine parlance, the metabolic abnormalities of critical illness and explore the common threads underlying the pathophysiology and the treatment of the two syndromes. The role of adiponectin in the metabolic abnormalities in both the metabolic syndrome and in sepsis are reviewed. The potential role of the pleiotropic effects of statins in the therapy of sepsis is also discussed.

Fasting serum leptin level correlates with mid-arm fat area in peritoneal dialysis patients

Leptin correlates with body fat content and plays a pivotal role in inflammatory response. This study aimed to investigate the relationships of fasting serum leptin levels and the anthropometric fat components among peritoneal dialysis (PD) patients. Fasting blood samples were obtained from 40 PD patients. Leptin levels were measured using a commercial enzyme-linked immunosorbent assay kit. Body weight (r=0.424; P=0.006), waist circumference (r=0.352; P=0.026), body mass index (BMI; r=0.483; P=0.002), body fat mass (r=0.352; P=0.026), high sensitivity C-reactive protein (hs-CRP; r=0.494; P=0.001), triceps skinfold thickness (TSF; r=0.505; P=0.001), mid-arm circumference (MAC; r=0.471; P=0.002), and mid-arm fat area (MAFA; r=0.564; P<0.001) were positively correlated, while high density lipoprotein (HDL)-cholesterol (r=-0.345; P=0.028) was negatively correlated with fasting serum leptin levels among the PD patients. Multivariate forward stepwise linear regression analysis showed that MAFA (R(2)=0.318, P=0.011) was the independent predictor of fasting serum leptin levels among the PD patients. In conclusion, fasting leptin level was positively associated with body fat composition (body weight, waist circumference, BMI, body fat mass, TSF, MAC, and MAFA) and hs-CRP among PD patients, and MAFA was the independent predictor of fasting serum leptin levels among the PD patients.

Impact of having one cardiovascular risk factor on other cardiovascular risk factor levels in adolescents

AIM

Little is known about the impact of having one cardiovascular (CV) risk factor on the levels of other CV risk factors in the general adolescent population. We hypothesized that when adolescents have one CV risk factor, the levels of other CV risk factors worsen simultaneously.

METHODS

Subjects consisted of 1,257 healthy adolescent volunteers (549 males and 708 females) aged 15-18 years. Abdominal obesity, hypertension, raised triglyceride levels, decreased HDL-cholesterol levels and hyperglycemia were used as CV risk factors. Homeostasis assessment of insulin resistance (HOMA-IR) was used as a surrogate marker of insulin resistance. Levels of four biomarkers, leptin, adiponectin, high-sensitive C-reactive protein, and desacyl-ghrelin, were also determined. Cut-offs for gender-specific individual CV risk factor levels were based on the 90th (or 10th) percentile values of the subjects in the present study.

RESULTS

The levels of all CV risk factors and HOMA-IR significantly and simultaneously worsened when adolescents had one CV risk factor in both genders. Having any one CV risk factor indicated the development of other CV risk factors in adolescents; in particular, we found that the development of abdominal obesity in male subjects had a harmful effect on the levels of other CV risk factors and was associated with the worsening of all four biomarkers examined.

CONCLUSIONS

It is important to determine the presence or absence of these CV risk factors before and/or during adolescence, because having one CV risk factor indicates the start of an accumulation of CV risk factors in the general adolescent population.

Expression of inflammatory molecules and associations with BMI in children

BACKGROUND

Adipose tissue secrets several adipokines that have been proposed to be enrolled in many inflammatory pathways. Our aim was to investigate the adipokine expression in adipose tissue and peripheral blood mononuclear cells (PBMCs) in children.

MATERIALS AND METHODS

Thirty-one (17 males and 14 females) healthy children aged 10.9 +/- 1.8 years with a body mass index (BMI) of 19.3 +/- 3.5 kg m(-2) were enrolled. Adipokines (TNF-alpha, IL-6 and leptin) gene expression was quantified by real-time quantitative PCR in adipose tissue and PBMCs from the same children. Their serum levels were also measured.

RESULTS

BMI was positively correlated with leptin gene expression in adipose tissue and with leptin serum levels (beta = 0.476, P = 0.006 and beta = 0.576, P = 0.003 respectively). Leptin's serum levels were positively correlated with leptin gene expression in adipose tissue (beta = 0.462, P = 0.02). Adipose tissue gene expression of leptin and TNF-alpha and serum leptin and TNF-alpha serum levels were positively correlated (beta = 0.752, P < 0.001, beta = 0.311 and P = 0.015 respectively). In PBMCs, a positive correlation between TNF-alpha and IL-6 expression was found (beta = 0.526, P = 0.042).

CONCLUSION

We demonstrated powerful correlations of adipokines gene expression in adipose tissue and PBMCs in children, underlying that these molecules share common pathways related to childhood obesity.

Adiponectin and leptin serum concentrations in patients with rheumatoid arthritis

Adipose tissue is regarded as an active metabolic and endocrine organ producing adipokines. The purpose of the study was to evaluate adiponectin and leptin concentrations in rheumatoid arthritis (RA) patients (pts) in relation to disease duration and activity. The study group consisted of 80 RA pts. Serum adiponectin and leptin concentrations remained within normal ranges. Adiponectin concentration correlated positively both with the age and disease duration. Both adipokines levels correlated negatively with glomerular filtration rate. There were significant positive correlations between adipokines' concentrations and lipid profile components (between adiponectin and HDL-cholesterol, leptin and total cholesterol and LDL-cholesterol). In pts with long-standing RA, there was a negative correlation between adiponectin and numbers of tender, swollen joints and a positive relationship between leptin level and DAS28. The results confirm adipokines' involvement in the process of inflammation and atherosclerosis: protective and antiinflammatory adiponectin effect and proatherogenic and proinflammatory leptin function.

Intricacies of fat

One of the most exciting cell biology fields of study concerns the physiology and pathology of fat. The basic assumptions once held concerning the function of adipose tissue have been shown to be oversimplified or sometimes completely wrong. Fat does more than store excess energy; it is actually the largest endocrine organ in the body, and it may be one of the most active. Adipocytes release hormones and other molecules that act on nearby tissues and travel through the vasculature to distant sites, such as the brain, skeletal muscle, and liver. Under conditions of normal weight, those signals help the body to suppress hunger, utilize glucose, and decrease the risk of cardiovascular disease. However, under conditions of obesity, the hormones (or the proteins that bind the hormones) become abnormal and can result in states of chronic inflammation leading to diabetes and heart disease. In addition, excessive fat can lead to the accumulation of lipid droplets in nonfat cells, including skeletal and cardiac muscle. Although some lipid droplets are used as an immediate source of energy for cells, large numbers of stored droplets can cause cellular damage and cell death. The purposes of this article are to review the normal and deviant signals released by fat cells, to draw a link between those signals and chronic diseases such as diabetes, and to discuss the role of exercise in reversing some of the deviant signaling perpetrated by excess fat.