Serum adiponectin in young adults--interactions with central adiposity, circulating levels of glucose, and insulin resistance: the CARDIA study

Adiponectin pathway activation dampens inflammation and enhances alveolar macrophage fungal killing via LC3-associated phagocytosis

Although innate immunity is critical for antifungal host defense against the human opportunistic fungal pathogen Aspergillus fumigatus, potentially damaging inflammation must be controlled. Adiponectin (APN) is an adipokine produced mainly in adipose tissue that exerts anti-inflammatory effects in adipose-distal tissues such as the lung. We observed 100% mortality and increased fungal burden and inflammation in neutropenic mice with invasive aspergillosis (IA) that lack APN or the APN receptors AdipoR1 or AdipoR2. Alveolar macrophages (AMs), early immune sentinels that detect and respond to lung infection, express both receptors, and APN-/- AMs exhibited an inflammatory/M1 phenotype that was associated with decreased fungal killing. Pharmacological stimulation of AMs with AdipoR agonist AdipoRon partially rescued deficient killing in APN-/- AMs that was dependent on both receptors. Finally, APN-enhanced fungal killing was associated with increased activation of the non-canonical LC3 pathway of autophagy. Thus, our study identifies a novel role for APN in LC3-mediated killing of A.fumigatus.

The Inflammatory Profile of Obesity and the Role on Pulmonary Bacterial and Viral Infections

Obesity is a globally increasing health problem, entailing diverse comorbidities such as infectious diseases. An obese weight status has marked effects on lung function that can be attributed to mechanical dysfunctions. Moreover, the alterations of adipocyte-derived signal mediators strongly influence the regulation of inflammation, resulting in chronic low-grade inflammation. Our review summarizes the known effects regarding pulmonary bacterial and viral infections. For this, we discuss model systems that allow mechanistic investigation of the interplay between obesity and lung infections. Overall, obesity gives rise to a higher susceptibility to infectious pathogens, but the pathogenetic process is not clearly defined. Whereas, viral infections often show a more severe course in obese patients, the same patients seem to have a survival benefit during bacterial infections. In particular, we summarize the main mechanical impairments in the pulmonary tract caused by obesity. Moreover, we outline the main secretory changes within the expanded adipose tissue mass, resulting in chronic low-grade inflammation. Finally, we connect these altered host factors to the influence of obesity on the development of lung infection by summarizing observations from clinical and experimental data.

VASPIN, ADIPONECTIN AND LEPTIN LEVELS IN TYPE 1 DIABETIC RATS INDUCED BY STREPTOZOTOCIN

Background

Adiponectin, vaspin and leptin are only a few of these numerous adipocytokines. Little is known about the behavior of adipocytokines and how adipose tissue metabolism is affected in this Type 1 DM model. In this study we investigated the serum levels of adiponectin, leptin, vaspin in streptozotocin(STZ) induced diabetic rats.

Material and methods

Twelve Spraque Dawley albino rats were included in the study. The animals were divided into two groups. The first group was diabetic (D) (n: 6) and 60mg / kg STZ was administered intraperitoneally (i.p.) to these rats. The second group was the non-diabetic control (ND) group (n: 6). All the animals were euthanized by cervical dislocation. Quantification of vaspin, Adiponectin, leptin in serum was performed using the ELISA kit.

Results

Adiponectin, vaspin levels of diabetic group were found to be statistically lower than of control group (p<0.05). Leptin levels were significantly higher in the diabetic group (P<0.05).

Conclusion

There is a need for new researches that can explain the relationship between Vaspin, Leptin and Adiponectin and Type 1 diabetes. New studies in this area will open new horizons for the identification of new biomarkers in the diagnosis and treatment of Type 1 diabetes.

Potential Roles of Adiponectin Isoforms in Human Obesity with Delayed Wound Healing

Adiponectin is an adipokine with anti-insulin resistance and anti-inflammatory functions. It exists in serum predominantly in three multimeric complexes: the trimer, hexamer, and high-molecular-weight forms. Although recent studies indicate that adiponectin promotes wound healing in rodents, its role in the wound healing process in humans is unknown. This study investigated the expression levels of adiponectin in adipose tissue and serum of women who experienced either normal or delayed wound healing after abdominal plastic surgery. We found that obese women with delayed healing had slightly lower total adiponectin levels in their adipose tissue compared with women with normal healing rates. Among the different isoforms of adiponectin, levels of the trimer forms were significantly reduced in adipose tissue, but not the serum, of obese women with delayed healing compared to women who healed normally. This study provides clinical evidence for a potential role of low-molecular-weight oligomers of adiponectin in the wound healing process as well as implications for an autocrine and/or paracrine mechanism of adiponectin action in adipose tissues.

The Metabolic Cytokine Adiponectin Inhibits Inflammatory Lung Pathology in Invasive Aspergillosis

Systemic immunity and metabolism are coregulated by soluble factors, including the insulin-regulating adipose tissue cytokine adiponectin. How these factors impact detrimental inflammatory responses during fungal infection remains unknown. In this study, we observed that mortality, fungal burden, and tissue histopathology were increased in adiponectin-deficient mice in a neutropenic model of invasive aspergillosis. Lung RNA sequencing, quantitative RT-PCR, and subsequent pathway analysis demonstrated activation of inflammatory cytokine pathways with upstream regulation by IL-1 and TNF in adiponectin-deficient mice with decreased/inhibited anti-inflammatory genes/pathways, suggesting broad cytokine-mediated pathology along with ineffective fungal clearance. Quantitative RT-PCR analysis confirmed increased transcription of IL-1a, IL-6, IL-12b, IL-17A/F, and TNF in adiponectin-deficient mice at early time points postinfection, with a specific increase in intracellular TNF in alveolar macrophages. Although eosinophil recruitment and activation were increased in adiponectin-deficient mice, mortality was delayed, but not decreased, in mice deficient in both adiponectin and eosinophils. Interestingly, neutrophil depletion was required for increased inflammation in adiponectin-deficient mice in response to swollen/fixed conidia, suggesting that immune suppression enhances detrimental inflammation, whereas invasive fungal growth is dispensable. Our results suggest that adiponectin inhibits excessive lung inflammation in invasive aspergillosis. Our study has therefore identified the adiponectin pathway as a potential source for novel therapeutics in immune-compromised patients with detrimental immunity to invasive fungal infection.

Reciprocal Inhibition of Adiponectin and Innate Lung Immune Responses to Chitin and Aspergillus fumigatus

Chitin is a structural biopolymer found in numerous organisms, including pathogenic fungi, and recognized as an immune-stimulating pathogen associated molecular pattern by pattern recognition molecules of the host immune system. However, programming and regulation of lung innate immunity to chitin inhalation in the context of inhalation of fungal pathogens such as Aspergillus fumigatus is complex and our understanding incomplete. Here we report that the systemic metabolism-regulating cytokine adiponectin is decreased in the lungs and serum of mice after chitin inhalation, with a concomitant decrease in surface expression of the adiponectin receptor AdipoR1 on lung leukocytes. Constitutive lung expression of acidic mammalian chitinase resulted in decreased inflammatory cytokine gene expression and neutrophil recruitment, but did not significantly affect lung adiponectin transcription. Exogenous recombinant adiponectin specifically dampened airway chitin-mediated eosinophil recruitment, while adiponectin deficiency resulted in increased airway eosinophils. The presence of adiponectin also resulted in decreased CCL11-mediated migration of bone marrow-derived eosinophils. In contrast to purified chitin, aspiration of viable conidia from the high chitin-expressing A. fumigatus isolate Af5517 resulted in increased neutrophil recruitment and inflammatory cytokine gene expression in adiponectin-deficient mice, while no significant changes were observed in response to the isolate Af293. Our results identify a novel role for the adiponectin pathway in inhibition of lung inflammatory responses to chitin and A. fumigatus inhalation.

Low Body Mass Index Is Associated with Higher Odds of COPD and Lower Lung Function in Low- and Middle-Income Countries

The relationship of body mass index (BMI) with lung function and COPD has been previously described in several high-income settings. However, few studies have examined this relationship in resource-limited settings where being underweight is more common. We evaluated the association between BMI and lung function outcomes across 14 diverse low- and middle-income countries. We included data from 12,396 participants aged 35-95 years and used multivariable regressions to assess the relationship between BMI with either COPD and lung function while adjusting for known risk factors. An inflection point was observed at a BMI of 19.8 kg/m². Participants with BMI < 19.8 kg/m² had a 2.28 greater odds (95% CI 1.83-2.86) of having COPD and had a 0.21 (0.13-0.30) lower FEV₁ and 0.34 (0.27-0.41) lower FEV₁/FVC z-score compared to those with BMI ≥ 19.8 kg/m². The association with lung function remained even after excluding participants with COPD. Individuals with lower BMI were more likely to have COPD and had lower lung function compared to those in higher BMI. The association with lung function remained positive even after excluding participants with COPD, suggesting that being underweight may also play a role in having worse lung function.

Ratio of low molecular weight serum adiponectin to the total adiponectin value is associated with type 2 diabetes through its relation to increasing insulin resistance

AIM

Among the three adiponectin isoforms, a lower ratio of high molecular weight (HMW) adiponectin to total adiponectin (TA) is well known to cause insulin resistance and type 2 diabetes (T2D). However, how the levels of other adiponectin isoforms, such as the middle molecular weight (MMW) and low molecular weight (LMW) isoforms, and their relative ratio to TA change in T2D subjects has not been determined. Therefore, we investigated the association of these adiponectin-related parameters with T2D.

METHODS

We examined the associations between adiponectin-related parameters and diabetes in a group of 394 T2D subjects and 374 controls (1st group) randomly selected from among the participants in our previous study. The associations between these parameters and the HOMA-IR in a 2nd group, consisting of the subjects remaining in the 1st group after the exclusion of subjects receiving diabetic medication, were also examined.

RESULT

In the 1st group, after adjusting for confounding factor, the levels of all the adiponectin isoforms and the HMW/TA ratio were significantly lower among the diabetic subjects than among the controls (all P values < 0.01). On the contrary, the LMW/TA ratio was significantly higher among the diabetic subjects (P < 0.01) and was positively associated with T2D (odds ratio = 8.64, P < 0.01). In the 2nd group, the HMW/TA ratio was inversely associated with the HOMA-IR; however, the LMW/TA ratio was positively associated with the HOMA-IR (β for LMW/TA ratio = 0.89, SE = 0.24, P < 0.001), similar to the association with T2D. The MMW/TA ratio was not associated with T2D or the HOMA-IR.

CONCLUSION

The current investigation demonstrated that, unlike the reduction in the levels of all the adiponectin isoforms and the HMW/TA ratio, an increased LMW/TA ratio was associated with T2D through its relation to insulin resistance.

Modulation of human airway smooth muscle biology by human adipocytes

Background

Asthma and obesity, two growing epidemics worldwide, may share an underlying causal relationship. Airway hyperresponsiveness (AHR), a defining component of asthma, has been documented in both ‘obese’ animal models and non-asthmatic obese individuals. However, there is a paucity of evidence that obesity-derived factors directly affect human airway smooth muscles (ASM).

Methods

Experiments were designed with primary ASM and adipocytes isolated from the same human tissue explants (n = 6). The modulatory effects of human adipocytes extracted from subcutaneous (extrathoracic) and visceral (intrathoracic) depots, on ASM biology was examined with respect to proliferation, migration, contractility and pro-inflammatory cytokine synthesis.

Results

Adipocyte-conditioned media as well as myocyte-adipocyte co-cultures failed to show any significant changes in the proliferative or migrational properties of the ASM. Adipocyte-conditioned media also had no effect on the contractility or relaxation of bovine tracheal muscle strips. In contrast, there was a moderate yet significant increase of IL-6 and eotaxin release by ASM incubated with adipocyte-conditioned media (P = 0.0035 and P = 0.0067, vs. control, respectively), thereby further consolidating the altered inflammatory state reported for both diseases.

Conclusion

We report, for the first time, that adipocytes from either subcutaneous or visceral depots can trigger an inflammatory state in the ASM, with negligible modulatory effects on hyperplasia, hypertrophy or contractile properties.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0741-z) contains supplementary material, which is available to authorized users.

The levels of adipokines in relation to hormonal changes during the menstrual cycle in young, normal-weight women

CONTEXT

The aim of this study was to assess the plasma leptin, adiponectin, resistin, visfatin/NAMPT, omentin-1, vaspin, apelin, TNF-α, IL-6 and RBP4 levels in relation to hormonal changes during the menstrual cycle in young, healthy, normal-weight women.

METHODS

The study involved 52 young, healthy, normal-weight women. Anthropometric parameters, body composition and levels of plasma leptin, adiponectin, resistin, visfatin/NAMPT, omentin-1, vaspin, apelin, TNF-α, IL-6 and RBP4 in addition to serum FSH, LH, estradiol, progesterone, 17-OH progesterone, androgens, SHBG and insulin concentrations were measured during a morning in fasting state three times: between days 2-4, days 12-14 and days 24-26 of the menstrual cycle.

RESULTS

Plasma adiponectin, omentin-1, resistin and visfatin/NAMPT, apelin, TNF-α, IL-6 and RBP4 concentrations were stable during the menstrual cycle, while leptin and vaspin levels were significantly higher in both the midcycle and the luteal phases than those in the follicular phase. Multivariate regression analyses revealed that changes in leptin and vaspin levels between the follicular and the luteal phase are strongly related to changes in total testosterone levels.

CONCLUSIONS

Our results revealed stable levels of adipokines during the phases of the physiological menstrual cycle, except for leptin and vaspin, which showed increased levels in both the midcycle and the luteal phases. This effect was significantly associated with changes in the secretion of testosterone, 17-OH progesterone and insulin in the luteal phase.

Myocardial Adiponectin Isoform Shift in Dogs with Congestive Heart Failure-A Comparison to Hibernating Brown Bears (Ursus arctos horribilis)

Adiponectin is the most abundant plasma adipokine, and is well known for its role in energy homeostasis and cardiac protection. In humans with dilated cardiomyopathy, myocardial adiponectin protein expression is reduced compared to normal hearts and has been implicated in the pathology of cardiomyopathy. Serum adiponectin levels are often conflicting, with higher levels associated with poor survival in humans with congestive heart failure (CHF). We evaluated adiponectin serum concentrations and myocardial protein expression in dogs with naturally occurring myxomatous mitral valve disease and CHF. We compared the findings to active and hibernating brown bears as bears are adapted to endure an extreme period of low cardiac output during their annual hibernation. Bears exhibited largely the active high-molecular weight (HMW) versus the low-molecular weight isoforms of myocardial adiponectin (HMW:LMW = 6.3) during both the active period and hibernation, while healthy dogs exhibited a more balanced mix of isoforms. Dogs with CHF expressed predominately HMW isoforms of adiponectin (HMW:LMW = 12.5), appearing more similar to bears. In contrast to humans, serum adiponectin was significantly lower in dogs with CHF and lowest levels in the severest CHF class. In both dogs and bears, myocardial adiponectin was expressed independent of circulating adiponectin concentrations, suggesting a local regulatory mechanism within the heart.

First and second trimester gestational weight gains are most strongly associated with cord blood levels of hormones at delivery important for glycemic control and somatic growth

BACKGROUND

Excessive gestational weight gain (GWG) during pregnancy is associated with adverse outcomes for mothers and offspring. Early, mid, and late pregnancy GWGs have different associations with fetal growth and later life adiposity, but associations with cord blood hormones, which might predict later health, are not well studied.

METHODS

In 978 pregnant women from the pre-birth Project Viva cohort, we calculated trimester-specific GWG using clinically recorded prenatal weights. Outcomes were levels of umbilical cord blood hormones related to fetal and postnatal growth. We used linear regression models adjusted for maternal race/ethnicity, pre-pregnancy BMI, parity, education, pregnancy smoking status and child sex; 2nd and 3rd trimester models were additionally adjusted for GWG in prior trimesters.

RESULTS

Mean±SD pre-pregnancy BMI was 24.9±5.5kg/m², 30% were non-white, and 63% were college graduates. Mean±SD cord blood hormone levels were insulin-like growth factor [IGF]-1 (56.4±24.3ng/mL), IGF-2 (408.5±92.7ng/mL), IGFBP-3 (1084±318ng/mL), insulin (6.5±7.2 uU/mL), C-peptide (1.0±0.6ng/mL), leptin (9.0±6.6ng/mL) and adiponectin (28.7±6.8μg/mL). Mean±SD 1st, 2nd and 3rd trimester GWG rates were 0.22±0.22, 0.49±0.19 and 0.46±0.22kg/wk. Greater 1st trimester GWG (per 0.2kg/wk) was associated with higher insulin (0.5 uU/mL; 95% CI 0.1, 0.9) and C-peptide (0.06ng/mL; 95% CI 0.02, 0.09) and lower adiponectin (-0.4μg/mL; 95% CI -0.9, 0.0). Greater 2nd trimester GWG (per 0.2kg/wk) was associated with higher IGF-1 (2.3ng/mL; 95% CI 0.6, 4.0), IGF-2 (7.9ng/mL; 95% CI 1.2, 14.6), IGFBP-3 (41.6ng/mL; 95% CI 19.4, 63.7) and leptin (0.9ng/mL; 0.4, 1.4). 3rd trimester GWG was not associated with cord blood hormones.

CONCLUSION

1st trimester weight gain appears to matter more for cord blood hormones related to offspring glucose/insulin regulation, whereas 2nd trimester gain matters more for hormones related to growth and adiposity.

Longitudinal associations between adiponectin and cardiac structure differ by hypertensive status: Coronary Artery Risk Development in Young Adults

OBJECTIVE

We studied the longitudinal association between adiponectin and cardiac structure and function 10 years later stratified by hypertension status.

METHODS

Multicenter longitudinal study of black and white men and women that began in 1985-1986, when participants were 18-30 years old. Adiponectin was measured at year 15(2000-2001). Echocardiograms were completed at year 25(2010-2011). Participants were stratified by the presence of hypertension. Risk factor-adjusted echocardiographic variables were compared across adiponectin quintiles. Linear and quadratic regression models were also derived for risk factor-adjusted echocardiographic variables.

RESULTS

Relative to the lowest quintile of adiponectin, participants from the highest quintile had a 6% lower LV mass index (LVMi) among normotensives, and an 8% higher LVMi among hypertensives. Among normotensive participants, regression analysis demonstrated a linear inverse relationship between adiponectin and LV mass, LVMi, posterior wall thickness (PWT) and ventricular septal thickness (VST) (all p≤0.05). Among hypertensive participants, regression analysis demonstrated a U-shaped relationship between adiponectin and LV mass, LVMi, PWT and VST (p≤0.005 for all quadratic terms).

CONCLUSIONS

Among normotensive participants, higher adiponectin may be a useful marker of less adverse future cardiac structure. Further study is required to see if adiponectin receptor agonists may provide a benefit among these individuals. Among hypertensive participants, further study is required to assess the prognostic and therapeutic use of adiponectin.

Non-Invasive Ventilation (NIV) and Homeostatic Model Assessment (HOMA) Index in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients with Chronic Hypercapnic Respiratory Failure: A Pilot Study

The effects of Non-invasive Ventilation (NIV) on Insulin Resistance (IR) in stable Chronic Obstructive Pulmonary Disease (COPD) patients have not been fully explored. The aim of this study was to assess the effects of NIV on IR and adiponectin levels during one year application of NIV in stable COPD patients with Chronic Hypercapnic Respiratory Failure. Twenty-five (25) stable COPD patients with Chronic Hypercapnic Respiratory Failure and with no self-reported comorbidities completed the study. NIV was administered in the spontaneous/timed mode via a full face mask using a bi-level positive airway pressure system. Spirometry, blood pressure, arterial blood gases, dyspnea, daytime sleepiness, serum fasting glucose and insulin levels were assessed. IR was assessed with the calculation of the Homeostatic Model Assessment (HOMA) index. Adiponectin was measured with radioimmunoassay. Study participants were re-evaluated on the first, third, sixth, ninth and twelfth month after the initial evaluation. There was a significant improvement in FEV1 values from the first month (34.1 ± 11.6% vs 37 ± 12.3%, p = 0.05). There was a significant decrease in IR by the ninth month of NIV use (3.4 ± 2.3 vs 2.2 ± 1.4, p < 0.0001), while adiponectin levels significantly improved from the first month of NIV use. Stepwise regression analysis revealed that baseline HOMA index was associated with paCO2 (β = 0.07 ± 0.02, p = 0.001), while baseline adiponectin levels were associated with FVC (β = 0.05 ± 0.02, p = 0.035) and the concentration of serum bicarbonate (HCO3-) (-β = 0.18 ± 0.06, p = 0.002). Insulin sensitivity and glucose metabolism as well as adiponectin levels improved along with the improvements in respiratory failure.

Association of serum adiponectin with asthma and pulmonary function in the Japanese population

Conflicting findings have been reported regarding the role of adiponectin in asthma. The aim of this study was to evaluate the association of adiponectin with pulmonary functions and asthma in the Japanese population. First, among a general population that participated in a previous study (group 1), we selected 329 subjects after excluding those with asthma, chronic obstructive pulmonary disease, and a smoking history and examined the associations of the serum total adiponectin levels with pulmonary functions. In a second cohort (group 2) consisting of 61 asthmatic patients and 175 control non-asthmatic subjects, we examined the associations between asthma and the levels of total, high (HMW), middle (MMW) and low (LMW) molecular weight adiponectin isoforms as well as the ratio of each isoform to total adiponectin level. Although the total adiponectin levels were not significantly different between the asthmatic and control subjects in group 2, the levels were significantly and positively associated with the forced expiratory volume in 1 s after adjustments for confounding factors (P < 0.05) in women in group 1. In group 2, the LMW adiponectin level was significantly higher and the MMW/total adiponectin ratio was significantly lower among the asthmatic subjects than among the control subjects after adjustments for confounding factors in both sexes (P < 0.05). The present study showed that a low total adiponectin level may lead to airway narrowing compatible with asthmatic airways in women, and higher LMW adiponectin levels and lower MMW/total adiponectin ratio are significantly associated with current asthma in both sexes.

Strategies for managing oxygenation in obese patients undergoing laparoscopic surgery

The worldwide trend toward increasing body mass index (BMI) has caused the anesthetic management of overweight, obese, and severely obese patients to become common. The increase in oxygen demand coupled with the anatomic and physiologic changes associated with excess adipose tissue make maintenance of oxygenation a major challenge during induction, maintenance and recovery from general anesthesia. It is crucial for anesthesiologists, surgeons and perioperative healthcare providers alike to have a thorough understanding of the impact of airway management and mechanical ventilation on the respiratory care of the obese in the immediate perioperative setting. In this manuscript we aim to discuss the consequences of obesity, particularly abdominal obesity, on respiratory physiology and provide suggestions on intraoperative ventilatory strategies to maintain oxygenation in the severely obese patient undergoing pneumoperitoneum.

Obesity attenuates gender differences in cardiovascular mortality

Background

To estimate cardiovascular disease (CVD) mortality in relation to obesity and gender.

Methods

Data from 11 prospective cohorts from four European countries including 23 629 men and 21 965 women, aged 24 to 99 years, with a median follow-up of 7.9 years were analyzed. Hazards ratios (HR) for CVD mortality in relation to baseline body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were estimated using Cox proportional hazards models with age as the timescale.

Results

Men had higher CVD mortality than women in all four BMI categories (<25.0, 25.0-29.9, 30.0-34.9 and ≥35.0 kg/m²). Compared with the lowest BMI category in women, multivariable adjusted HRs (95% confidence intervals) for higher BMI categories are 1.0 (0.8-1.4), 1.6 (1.1-2.1) and 2.8 (2.0-3.8) in women and 2.8 (2.2-3.6), 3.1 (2.5-3.9), 3.8 (2.9-4.9) and 5.4 (3.8-7.7) in men, respectively. Similar findings were observed for abdominal obesity defined by WC, WHR or WHtR. The gender difference was slightly smaller in obese than in non-obese individuals; but the interaction was statistically significant only between gender and WC (p = 0.02), and WHtR (p = 0.01). None of the interaction terms was significant among non-diabetic individuals.

Conclusions

Men had higher CVD mortality than women across categories of anthropometric measures of obesity. The gender difference was attenuated in obese individuals, which warrants further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-014-0144-5) contains supplementary material, which is available to authorized users.

Correlation study on adiponectin gene SNP45 and long-term oxidative stress in patients with diabetes and carotid atherosclerosis

The aim of the present study was to investigate the correlation between the adiponectin gene single nucleotide polymorphism (SNP)45 T/G and long-term oxidative stress in type II diabetes mellitus (T2DM) patients with carotid atherosclerosis. Patients with T2DM were divided into non-carotid atherosclerosis and carotid atherosclerosis groups, which were then subsequently divided into TT and TG + GG groups according to the adiponectin SNP45 T/G genotypes. Enzyme-linked immunosorbent assay, TaqMan probe quantitative polymerase chain reaction (PCR), PCR-TaqMan, color Doppler and other methods were used to determine the adiponectin levels, gene polymorphisms, acquired mitochondrial DNA (mtDNA) A3243G somatic cell mutation rates and the carotid intima-media thickness. The somatic cell mutation rate of acquired mtDNA A3243A/G in the T2DM carotid atherosclerosis group was significantly higher compared with the group without carotid atherosclerosis. In addition, the acquired mtDNA A3243A/G somatic cell mutation rate in the T2DM carotid atherosclerosis group with the adiponectin gene SNP45 TT genotype was significantly lower compared with the SNP45 TG/GG genotype group. T2DM combined with carotid atherosclerosis was associated with long-term oxidative stress. In addition, adiponectin gene SNP45 T/G was associated with increased mtDNA A3243A/G somatic mutation rates in T2DM patients with carotid atherosclerosis. Therefore, adiponectin gene polymorphisms may lead to diabetes atherosclerosis through oxidative stress.

Is there a link between obesity and asthma?

Increasing epidemiological data identify a link between obesity and asthma incidence and severity. Based on experimental data, it is possible that shared inflammatory mechanisms play a role in determining this linkage. Although controversial, the role of adipokines may be central to this association and the maintenance of the asthma phenotype. While leptin and adiponectin have a causal link to experimental asthma in mice, data in humans are less conclusive. Recent studies demonstrate that adipokines can regulate the survival and function of eosinophils and that these factors can affect eosinophil trafficking from the bone marrow to the airways. In addition, efferocytosis, the clearance of dead cells, by airway macrophages or blood monocytes appears impaired in obese asthmatics and is inversely correlated with glucocorticoid responsiveness. This review examines the potential mechanisms linking obesity to asthma.

High sputum total adiponectin is associated with low odds for asthma

OBJECTIVE

Adipose tissue produces adiponectin, an anti-inflammatory protein. High systemic total adiponectin is associated with a low risk for incident asthma but the association with lung adiponectin is not known. Our objective was to evaluate the association between sputum total adiponectin and asthma.

METHODS

This case-control study included 44 cases with objectively-confirmed asthma and an equal number of body mass index (BMI) and sex-matched controls. Serum and sputum adiponectin were estimated by ELISA and Western Blot technique, respectively. While Fisher's exact test, t-test and Spearman's correlations were used for univariate analyses, Spearman and regression analyses were performed for multivariable analyses.

RESULTS

While high-molecular-weight adiponectin was the dominant isoform in serum, medium-molecular-weight isoform was dominant in sputum. Sputum total adiponectin was not correlated with serum adiponectin or BMI. Sputum total adiponectin was lower among asthmatics than controls (p = 0.03), although individual sputum isoforms were not similarly associated. High sputum total adiponectin was associated with lower odds for asthma (OR 0.33, 95% C.I. 0.12, 0.91), even after adjustment for systemic adiposity measures including serum adiponectin.

CONCLUSIONS

High sputum total adiponectin predicted lower odds for asthma, even after adjustment for serum adiponectin. Although not studied, it is possible that pharmacological modulation of sputum adiponectin may suggest new ways to prevent and/or treat asthma.

Adiponectin, Leptin, and Resistin in Asthma: Basic Mechanisms through Population Studies

Adipokines, factors produced by adipose tissue, may be proinflammatory (such as leptin and resistin) or anti-inflammatory (such as adiponectin). Effects of these adipokines on the lungs have the potential to evoke or exacerbate asthma. This review summarizes basic mechanistic data through population-based and clinical studies addressing the potential role of adipokines in asthma. Augmenting circulating concentrations of adiponectin attenuates allergic airway inflammation and airway hyperresponsiveness in mice. Murine data is supported by human data that suggest that low serum adiponectin is associated with greater risk for asthma among women and peripubertal girls. Further, higher serum total adiponectin may be associated with lower clinical asthma severity among children and women with asthma. In contrast, exogenous administration of leptin results in augmented allergic airway hyperresponsiveness in mice. Alveolar macrophages obtained from obese asthmatics are uniquely sensitive to leptin in terms of their potential to augment inflammation. Consistent with this basic mechanistic data, epidemiologic studies demonstrate that higher serum leptin is associated with greater asthma prevalence and/or severity and that these associations may be stronger among women, postpubertal girls, and prepubertal boys. The role of adipokines in asthma is still evolving, and it is not currently known whether modulation of adipokines may be helpful in asthma prevention or treatment.

Novel noninvasive anthropometric measure in preterm and full-term infants: normative values for waist circumference:length ratio at birth

BACKGROUND

Waist circumference:length ratio (WLR) and ponderal index (PI) appear to be useful markers of visceral and total adiposity, respectively. However, there are no normative birth data across the full range of gestational ages.

METHODS

In this retrospective cohort study of 500 preterm and 1,426 full-term infants, born in 1998 and 2008 at three military hospitals, the percentile growth curves for WLR and PI were calculated. There were no sex differences, and results were combined to obtain values from 26 to 42 wk gestation.

RESULTS

Between 26 and 42 wk gestation, median birth WLR increased from 0.55 to 0.62, and median PI increased from 21.1 to 25.6. The adjusted mean WLR at birth among infants born <34 wk increased from 0.55 in 1998 to 0.58 in 2008 (P = 0.048), suggesting that early-preterm infants born in 2008 had greater abdominal adiposity than those born in 1998.

CONCLUSION

We report normative birth data for WLR and PI in preterm and full-term infants by gestational age and sex. WLR and PI may be useful as clinical markers of visceral and overall adiposity. In conjunction with other anthropometric measures, WLR and PI may be useful to monitor postnatal nutrition and growth and assess risk for later obesity and cardiometabolic disorders.

Neonatal cord blood adiponectin and insulin levels in very low birth weight preterm and healthy full-term infants

BACKGROUND

There are few studies concerning adiponectin and insulin concentration in cord blood of very low birth weight (VLBW) preterm and full-term newborns, small and appropriate for gestational age (GA).

AIM

To compare adiponectin and insulin concentrations between preterm and full-term infants, and to determine their relation with birth weight (BW) and size for GA.

METHODS

A cross-sectional study of VLBW preterm newborns with GA < 32 weeks and BW < 1500 g, and full-term newborns with GA > 37 weeks born at our hospital between January 2010 and May 2011, was conducted.

EXCLUSION CRITERIA

major congenital malformation, inborn errors of metabolism, chromosomal anomalies. Adiponectin was determined by enzimoimunoassay with ELISA kits (R&D Systems, Minneapolis, MN) and insulin was assayed by chemiluminescence method.

RESULTS

A total of 127 newborns were studied, 55 VLBW preterm (28 SGA), and 72 full-term (7 SGA). Insulin cord blood concentrations in preterm and full-term newborns were similar. Adiponectin concentrations were significantly lower in preterm than in full-term infants: 1.57 ± 0.74 pg/ml versus 2.4 ± 0.22 pg/ml (p < 0.001), respectively. Regression analyses showed that, after controlling for several neonatal and maternal factors, preterm birth was the only significant predictor of adiponectin concentrations.

CONCLUSION

Being born prematurely is the main determinant factor for lower adiponectin concentration in umbilical cord blood of newborns.

Adiponectin in pulmonary disease and critically ill patients

Adiponectin is a predominantly anti-inflammatory protein produced by adipose tissue with possible signalling activity in the lung. It is increasingly associated with inflammatory pulmonary diseases, such as asthma and chronic obstructive pulmonary disease (COPD), and in critical illness. Although mouse studies indicate causative associations between adiponectin and asthma and COPD, the human literature in this regard is inconclusive. Some, but not all, studies demonstrate that serum adiponectin concentrations are inversely associated with asthma prevalence among premenopausal women and peripubertal girls. On the other hand, serum adiponectin concentrations are associated with lower asthma severity among boys but greater severity among men. Further, case-control studies demonstrate higher systemic and airway adiponectin concentrations in primarily male COPD patients than controls. Systemic adiponectin is positively associated with lung function in healthy adults but inversely associated in studies of male subjects with COPD. Murine and human studies further show contradictory associations of systemic adiponectin with critical illness. Higher premorbid systemic adiponectin concentrations are associated with improved survival from sepsis in mice. On the other hand, higher systemic adiponectin concentrations on day 1 of critical illness are associated with lower survival in critically ill patients with respiratory failure. In the absence of adequate longitudinal data, it is not possible to determine whether the adiponectin derangements are the consequence or the cause of the disease studied. Future research will determine whether modulation of adiponectin, independent of BMI, may be helpful in the prevention or treatment of asthma, COPD or critical illness.

Effect of allergen inhalation on airway oxidant stress, using exhaled breath condensate 8-isoprostane, in mild asthma

OBJECTIVE

Exhaled breath condensate (EBC) 8-isoprostane concentrations are increased in asthma, but it is not known if they acutely change following bronchoprovocation. The objective of this study was to evaluate EBC 8-isoprostane concentrations following allergen-induced bronchoprovocation in asthma.

METHODS

This comparison study included eight mild atopic asthmatics and six controls. Asthmatics were challenged with inhaled specific allergen, methacholine, and irrelevant allergen in random order. Controls were challenged with irrelevant allergen. EBCs collected at 0, 3, 6, 9, and 23 hours by the R-tube method were measured for 8-isoprostanes by ELISA technique. Repeated measures ANOVA technique was used for analysis.

RESULTS

EBC 8-isoprostane concentrations did not change following any inhalational challenge, as compared to baseline, in either asthmatics or controls.

CONCLUSIONS

EBC 8-isoprostane concentrations do not acutely change following bronchoprovocation in subjects with mild asthma.

Gender differences in the association of visceral and subcutaneous adiposity with adiponectin in African Americans: the Jackson Heart Study

BACKGROUND

Adiponectin, paradoxically reduced in obesity and with lower levels in African Americans (AA), modulates several cardiometabolic risk factors. Because abdominal visceral adipose tissue (VAT), known to be reduced in AA, and subcutaneous adipose tissue (SAT) compartments may confer differential metabolic risk profiles, we investigated the associations of VAT and SAT with serum adiponectin, separately by gender, with the hypothesis that VAT is more strongly inversely associated with adiponectin than SAT.

METHODS

Participants from the Jackson Heart Study, an ongoing cohort of AA (n = 2,799; 64% women; mean age, 55 ± 11 years) underwent computer tomography assessment of SAT and VAT volumes, and had stored serum specimens analyzed for adiponectin levels. These levels were examined by gender in relation to increments of VAT and SAT.

RESULTS

Compared to women, men had significantly lower mean levels of adiponectin (3.9 ± 3.0 μg/mL vs. 6.0 ± 4.4 μg/mL; p < 0.01) and mean volume of SAT (1,721 ± 803 cm(3) vs. 2,668 ± 968 cm(3); p < 0.01) but significantly higher mean volume of VAT (884 ± 416 cm(3) vs. 801 ± 363 cm(3); p < 0.01). Among women, a one standard deviation increment in VAT was inversely associated with adiponectin (β = - 0.13; p < 0.0001) after controlling for age, systolic blood pressure, fasting plasma glucose, high-density lipoprotein cholesterol, triglycerides, education, pack-years of smoking and daily intake of alcohol. The statistically significant inverse association of VAT and adiponectin persisted after additionally adjusting for SAT, body mass index (BMI) and waist circumference (WC), suggesting that VAT provides significant information above and beyond BMI and WC. Among men, after the same multivariable adjustment, there was a direct association of SAT and adiponectin (β = 0.18; p = 0.002) that persisted when controlling for BMI and WC, supporting a beneficial effect of SAT. Insulin resistance mediated the association of SAT with adiponectin in women.

CONCLUSION

In African Americans, abdominal visceral adipose tissue had an inverse association with serum adiponectin concentrations only among women. Abdominal subcutaneous adipose tissue appeared as a protective fat depot in men.

Insulin resistance and adipose-derived hormones in young men with untreated obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) increases the risk for insulin resistance (IR). The mechanisms that link the two are not clear and are frequently confounded by obesity. OSA is associated with alterations in adipose-derived hormones (adipokines) that increase IR; however, previous studies have focused on middle-aged and older adults. The objective of this study was to determine if IR and alterations in adipokines exist in young men with OSA, independent of obesity.

METHODS

Subjects were assigned into the following groups based on body mass index and presence of OSA: obese with OSA (OSA, n = 12), obese without OSA (NOSA, n = 18), and normal weight without OSA (CON, n = 15). Fasting blood was obtained for batch analysis of biomarkers of IR. The homeostasis model assessment (HOMA) method was used to assess IR.

RESULTS

HOMA and leptin were higher in the OSA group than the CON group. There were no differences in insulin, tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) between the OSA and NOSA groups. Adiponectin was lower in the OSA group vs. NOSA and CON; however, when controlled for central abdominal fat (CAF), the difference was nullified. When controlled for total body adiposity, however, CAF was 24 % higher in the subjects with OSA vs. subjects without OSA.

CONCLUSIONS

These findings suggest that excess CAF in young men with OSA may contribute to risk for type 2 diabetes indirectly by a degree that would otherwise not be reached through obesity, although further research is needed.

Low serum adiponectin predicts future risk for asthma in women

RATIONALE

Our previous cross-sectional study showed that serum adiponectin is inversely associated with asthma among women. However, it is not known if serum adiponectin predicts future development of asthma or if asthma affects subsequent serum adiponectin concentrations among women.

OBJECTIVES

To determine longitudinal association between serum adiponectin and incident asthma among women.

METHODS

We used data from examinations at Years 10, 15, and 20 of the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. In our primary analysis, the association of CARDIA Year 15 serum adiponectin concentration with Year 20 incident asthma was evaluated. In our secondary analysis, the converse direction, that is, the association of CARDIA Year 10 prevalent asthma with Year 15 serum adiponectin, was evaluated, using logistic regression techniques.

MEASUREMENTS AND MAIN RESULTS

Our primary analysis included 1,450 women, mostly premenopausal. Multivariable analyses demonstrated that the lowest tertile of Year 15 serum adiponectin concentration (<7 mg/L) predicted significantly higher risk for incident asthma at Year 20 among women (odds ratio, 2.07; 95% confidence interval, 1.05, 4.10), and particularly among current smokers (interaction P = 0.051). Further, low serum adiponectin was more important than body mass index in predicting the risk for incident asthma among women. We also showed that the converse relationship was not true; that is, Year 10 prevalent asthma did not predict Year 15 serum adiponectin concentrations in women.

CONCLUSIONS

Serum adiponectin affects future risk for asthma in women and not vice versa. Measures that raise systemic adiponectin concentrations may lead to newer ways to prevent asthma among women, particularly among those who smoke.

Leptin, adiponectin and pulmonary diseases

Adipose tissue produces leptin and adiponectin - energy-regulating adipokines that may also play a role in inflammatory pulmonary conditions, as suggested by some murine studies. Leptin and adiponectin and their respective receptors are expressed in the human lung. The association between systemic or airway leptin and asthma in humans is currently controversial, particularly among adults. The majority of the evidence among children however suggests that systemic leptin may be associated with greater asthma prevalence and severity, particularly among prepubertal boys and peripubertal/postpubertal girls. Systemic and airway leptin concentrations may also be disproportionately higher in chronic obstructive pulmonary disease (COPD) patients, particularly among women, and reflect greater airway inflammation and disease severity. Quite like leptin, the association between systemic and airway adiponectin and asthma in humans is also controversial. Some but not all studies, demonstrate that serum adiponectin concentrations are protective against asthma among premenopausal women and peripubertal girls. On the other hand, serum adiponectin concentrations are inversely associated with asthma severity among boys but positively associated among men. Further, systemic and airway adiponectin concentrations are higher in COPD patients than controls, as demonstrated by case-control studies of men. Systemic adiponectin is also positively associated with lung function in healthy adults but inversely associated with lung function in subjects with COPD. It is therefore possible that pro-inflammatory effects of adiponectin dominate under certain physiologic conditions and anti-inflammatory effects under others. The adipokine-lung disease literature has critical gaps that include a lack of adequately powered longitudinal or weight-intervention studies; inadequate adjustment for confounding effect of obesity; and unclear understanding of potential sex interactions. It is also uncertain whether adipokine derangements precede pulmonary disease or are a consequence of it. Future research will determine whether modulation of adipokines, independent of BMI, may allow novel ways to prevent or treat inflammatory pulmonary conditions.

Metabolic syndrome and leptin are associated with adverse pathological features in male colorectal cancer patients

AIM

Metabolic syndrome (MetS) describes a clustering of factors including central obesity, hypertension and raised plasma glucose, triglycerides and high-density lipoprotein (HDL) cholesterol. Central obesity is associated with a risk for colorectal cancer, but the impact of MetS on colorectal cancer biology and outcomes is unclear.

METHOD

A prospective observational study of colorectal cancer patients was carried out in an Irish population. Patients underwent metabolic and anthropometric assessment before treatment, including measurement of serum hormones and adipokines and CT measurement of visceral fat. MetS was defined according to the International Diabetes Federation definition(3) .

RESULTS

One-hundred and thirty consecutive colorectal cancer patients (66 men and 64 women) were recruited. MetS was diagnosed in 38% patients compared with the population norms reported at 21%(21) . Male patients had a significantly greater visceral fat area compared with female patients. MetS was associated with node-positive disease (P = 0.026), percentage nodal involvement (P = 0.033) and extramural vascular invasion (P = 0.049) in male patients but no significant association was observed in female patients. HDL cholesterol was also significantly associated with a more advanced pathological stage (P = 0.014) and node-positive disease (P = 0.028). Leptin was associated with nodal status (P = 0.036), microvascular invasion (P = 0.054), advanced pathological stage (P = 0.046) and more advanced Dukes stage (P = 0.042).

CONCLUSION

We report a high prevalence of MetS and visceral obesity in a colorectal cancer population. MetS and plasma leptin are associated with a more aggressive tumour phenotype in male patients only.

Sucrose, high-sugar foods, and risk of endometrial cancer--a population-based cohort study

BACKGROUND

Consumption of high-sugar foods stimulates insulin production, which has been associated with endometrial cancer. Although a relationship between sucrose, high-sugar food consumption, and endometrial cancer risk is biologically plausible, this hypothesis has previously been explored in very few studies.

METHODS

We used data from the Swedish Mammography Cohort, including 61,226 women aged 40 to 74 years. We examined the association between consumption of total sucrose, high-sugar foods (at baseline 1987-1990 and 1997) and endometrial cancer risk by using Cox proportional hazards models to estimate incidence rate ratios (RR) with 95% CI.

RESULTS

During 18.4 years of follow-up, 729 participants were diagnosed with incident endometrial cancer. Total sucrose intake and consumption of sweet buns and cookies was associated with increased risk of endometrial cancer. RRs (with 95% CIs) for consuming more than 35 grams of sucrose per day and consuming sweet buns and cookies more than 3 times per week were 1.36 (1.04-1.77) and 1.42 (1.15-1.75) as compared with less than 15 grams of sucrose per day and consuming sweet buns and cookies less than 0.5 times per week, respectively. RRs for consuming more than 15 grams of sucrose per day as compared with 15 grams or less were 1.97 (1.27-3.04) among obese women and 1.56 (1.20-2.04) among women with low fat intake.

CONCLUSIONS

These data indicate that sucrose intake and consumption of sweet buns and cookies may be associated with increased risk of endometrial cancer.

IMPACT

Given the high intake of sweetened foods, these results have public health implications in terms of prevention of endometrial cancer.

Renal cell cancer among African Americans: an epidemiologic review

Incidence rates for renal cell cancer, which accounts for 85% of kidney cancers, have been rising more rapidly among blacks than whites, almost entirely accounted for by an excess of localized disease. This excess dates back to the 1970s, despite less access among blacks to imaging procedures in the past. In contrast, mortality rates for this cancer have been virtually identical among blacks and whites since the early 1990s, despite the fact that nephrectomy rates, regardless of stage, are lower among blacks than among whites. These observations suggest that renal cell cancer may be a less aggressive tumor in blacks. We have reviewed the epidemiology of renal cell cancer, with emphasis on factors which may potentially play a role in the observed differences in incidence and mortality patterns of renal cell cancer among blacks and whites. To date, the factors most consistently, albeit modestly, associated with increased renal cell cancer risk in epidemiologic studies among whites--obesity, hypertension, cigarette smoking--likely account for less than half of these cancers, and there is virtually no epidemiologic evidence in the literature pertaining to their association with renal cell cancer among blacks. There is a long overdue need for detailed etiologic cohort and case-control studies of renal cell cancer among blacks, as they now represent the population at highest risk in the United States. In particular, investigation of the influence on renal cell cancer development of hypertension and chronic kidney disease, both of which occur substantially more frequently among blacks, is warranted, as well as investigations into the biology and natural history of this cancer among blacks.

Serum adiponectin in relation to body mass index and other correlates in black and white women

PURPOSE

Adiponectin is a promising biomarker linking obesity and disease risk; however, limited data are available regarding adiponectin in black women among whom obesity is highly prevalent.

METHODS

A cross-sectional analysis was conducted to assess racial differences and correlates of serum adiponectin measured in 996 black and 996 white women enrolled in the Southern Community Cohort Study through Community Health Centers in 12 southeastern states from 2002 to 2006.

RESULTS

Black subjects had significantly lower adiponectin levels than white subjects (median 10.9 vs 14.9 μg/mL, Wilcoxon p < .0001). Among black subjects, adiponectin was lower among overweight and obese women compared with healthy weight women but showed no clear decreasing trend with increasing severity of obesity; adjusted geometric means (95% confidence interval) were 15.0 [13.8-16.4], 11.5 [10.6-12.5], 9.7 [9.0-10.6], 11.4 [10.3-12.6], and 10.9 [9.5-12.6] μg/mL for body mass index [BMI] categories of 18.5-24.9, 25-29.9, 30-34.9, 35-39.9, and 40-45, p for trend <.0001). In contrast, among whites there was a monotonic reduction in adiponectin over increasing BMI (adjusted geometric means = 19.9 [18.3-21.7], 15.1 [13.9-16.4], 14.3 [13.2-15.5], 12.5 [11.2-13.9], and 11.0 [9.7-12.5] μg/mL, p for trend <.0001). BMI, age, high-density lipoprotein cholesterol, and hypertension were important correlates of adiponectin in both groups.

CONCLUSIONS

Among women, racial differences exist in both the magnitude and form of the adiponectin-BMI association.

Serum adiponectin is positively associated with lung function in young adults, independent of obesity: the CARDIA study

Rationale

Adipose tissue produces adiponectin, an anti-inflammatory protein. Adiponectin deficiency in mice is associated with abnormal post-natal alveolar development.

Objective

We hypothesized that lower serum adiponectin concentrations are associated with lower lung function in humans, independent of obesity. We explored mediation of this association by insulin resistance and systemic inflammation.

Methods and Measurements

Spirometry testing was conducted at years 10 and 20 follow-up evaluation visits in 2,056 eligible young adult participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Body mass index, serum adiponectin, serum C-reactive protein (a marker of systemic inflammation), and insulin resistance were assessed at year 15.

Main Results

After controlling for body mass index, years 10 and 20 forced vital capacity (FVC) were 81 ml and 82 ml lower respectively (p = 0.004 and 0.01 respectively) in the lowest vs. highest adiponectin quartiles. Similarly, years 10 and 20 forced expiratory volume in one second (FEV₁) were 50 ml and 38 ml lower (p = 0.01 and 0.09, respectively) in the lowest vs. highest adiponectin quartiles. These associations were no longer significant after adjustment for insulin resistance and C-reactive protein. Serum adiponectin was not associated with FEV₁/FVC or peak FEV₁.

Conclusions

Independent of obesity, lower serum adiponectin concentrations are associated with lower lung function. The attenuation of this association after adjustment for insulin resistance and systemic inflammation suggests that these covariates are on a causal pathway linking adiponectin and lung function.

Insulin resistance in African-American and Caucasian women: differences in lipotoxicity, adipokines, and gene expression in adipose tissue and muscle

OBJECTIVES

We tested whether African-American (AA) women are different from Caucasian women in regard to lipotoxicity, adipokines, and gene expression in adipose tissue and muscle.

DESIGN

Insulin sensitivity (S(I)), plasma adipocytokine levels, intramyocellular lipid (IMCL), and the expression of candidate genes in adipose tissue and muscle were measured in AA and Caucasian women.

SETTING

This study was performed in an ambulatory general clinical research center.

SUBJECTS

Subjects were healthy, nondiabetic AA and Caucasian women.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

Comparison of S(I), IMCL, plasma adiponectin, and the expression of candidate genes regulating adipogenesis, lipogenesis, and inflammation in adipose tissue and muscle.

RESULTS

AA had lower plasma adiponectin and IMCL when compared with Caucasian women with similar S(I). In sc adipose tissue (SAT), the expression of genes involved in adipogenesis including peroxisomal proliferator-activated receptor-gamma (PPARgamma) and lipin-1beta were also reduced in SAT of AA subjects (19%, P = 0.06, and 25%, P = 0.05, respectively). Similarly, 1-acylglycerol-3-phosphate acyltransferase 2 (AGPAT 2), stearoyl-coenzyme A desaturase-1 (SCD1), and CD36 mRNA expression was significantly reduced in SAT by 19, 54, and 28% respectively (P < 0.01 for all) in AA compared with Caucasian women. Yet the expression of CD68 in SAT was similar in both ethnic groups. Gene expression studies in muscle revealed a 31% reduction in expression of AGPAT 2 and a 72% reduction in SCD1 genes in AA.

CONCLUSION

AA women demonstrated lower expression of several PPARgamma-responsive genes in adipose tissue, lower plasma adiponectin, and decreased IMCL levels as compared with Caucasians, which suggests that African-Americans may be protected from lipotoxicity. Together these data suggest significant ethnic differences in the pathophysiology of insulin resistance.

Relation of C-reactive protein to abdominal adiposity

Inflammation is a crucial element in the development of cardiovascular disease. Serum measurements of inflammation through high-sensitivity C-reactive protein (hsCRP) can lead to improved risk stratification of patients for risk for hard cardiovascular events. There is evidence that anthropomorphic measurements of obesity are important determinants of systemic inflammation. Online databases (e.g., PubMed and Medline) were searched for original research reports published in English from June 1990 to June 2009 examining the relations between hsCRP; anthropomorphic measurements of obesity including body mass index, waist-to-hip ratio, waist circumference, and visceral adiposity; and cardiovascular disease. When possible, correlation coefficients were used to compare data among studies. Measurements of abdominal obesity are associated with systemic inflammation as measured by hsCRP (r = 0.40 to 0.61). The association between hsCRP and abdominal adiposity persists when taking into account body mass index. Elevation of hsCRP might be reversible with weight loss and exercise. In conclusion, clinical measurements of abdominal adiposity readily provide data elucidating the systemic inflammatory state of patients and can help guide intensity of lifestyle modifications, thus leading to reduction of this inflammation.

Admixture mapping of obesity-related traits in African Americans: the Atherosclerosis Risk in Communities (ARIC) Study

Obesity is an important cause of morbidity and mortality worldwide. In the United States, the prevalence of obesity is higher in African Americans than whites, even after adjustment for socioeconomic status (SES). This leads to the hypothesis that differences in genetic background may contribute to racial/ethnic differences in obesity-related traits. We tested this hypothesis by conducting a genome-wide admixture mapping scan using 1,350 ancestry-informative single-nucleotide polymorphisms (SNPs) in 3,531 self-identified blacks from the Atherosclerosis Risk in Communities (ARIC) study. We used these markers to estimate the overall proportions of European ancestry (PEAs) for each individual and then scanned for the association between PEA and obesity-related traits (both continuous and dichotomous) at each locus. The median (interquartile range) PEA was 0.151 (0.115). PEA was inversely correlated with continuous BMI, weight, and subscapular skinfold thickness, even after adjusting for socioeconomic factors. In contrast, PEA was positively correlated with BMI-adjusted waist circumference. Using admixture mapping on dichotomized traits, we identified a locus on 2p23.3 to be suggestively associated with BMI (locus-specific lod = 4.11) and weight (locus-specific lod = 4.07). After adjusting for global PEA, each additional copy of a European ancestral allele at the 2p23.3 peak was associated with a BMI decrease of approximately 0.92 kg/m(2) (P = 2.9 x 10(-5)). Further mapping in this region on chromosome 2 may be able to uncover causative variants underlying obesity, which may offer insights into the control of energy homeostasis.

Obesity, adipokines, and lung disease

This review summarizes the state of the current literature relating to the associations of lung disease on obesity and adipokines (proteins produced by adipose tissue) in humans. Obesity is an independent risk factor for asthma. Recent studies suggest that obesity is also an independent risk factor for chronic airflow obstruction, as is seen with chronic obstructive pulmonary disease (COPD). The mechanistic basis for these associations in humans is not established, although a possible role for adipokines has been invoked. Leptin, a proinflammatory adipokine, and adiponectin, an anti-inflammatory adipokine, are causally associated with asthma in mice. Although human studies are currently inconclusive, high-serum leptin and low-serum adiponectin concentrations predict asthma, independent of obesity, in select population groups, such as premenopausal women in the United States. In contradistinction, low-serum leptin and high-serum adiponectin concentrations are associated with stable COPD, although these associations are likely confounded by fat mass. Interestingly, leptin may promote systemic and airway inflammation in stable COPD patients. On the other hand, COPD may upregulate systemic and lung adiponectin expression. The precise mechanism and significance of the associations between these adipokines and lung disease at the current stage is confusing and frankly paradoxical in places. This area of research needs additional study that may open up novel therapeutic strategies for these lung diseases.

Altered resting and exercise respiratory physiology in obesity

Obesity, particularly severe obesity, affects resting and exercise-related respiratory physiology. Severe obesity classically produces a restrictive ventilatory abnormality characterized by reduced expiratory reserve volume. Obstructive ventilatory abnormality may also be associated with abdominal obesity. Decreased peak work rates are usually seen among obese subjects in a setting of normal or decreased ventilatory reserve and normal cardiovascular response to exercise. Weight loss may reverse many adverse physiologic consequences of severe obesity on the respiratory system.

Coffee drinking and risk of endometrial cancer--a population-based cohort study

Coffee drinking has been reported to have beneficial effects on insulin resistance, which has been directly associated with endometrial cancer. Although a relationship between coffee consumption and endometrial cancer risk is biologically plausible, this hypothesis has been previously explored in only 2 prospective studies, with a small number of cases. We used data from the Swedish Mammography Cohort, a population-based prospective cohort study of 60,634 women. During 17.6 years of follow-up, 677 participants were diagnosed with incident endometrial cancer (adenocarcinoma). We examined the association between self-reported coffee consumption (at baseline 1987-90 and in 1997) and endometrial cancer risk using Cox proportional hazards models. Each additional cup (200 g) of coffee per day was associated with a rate ratio (RR) of 0.90 [95% confidence interval (CI), 0.83-0.97]. In women drinking 4 or more cups of coffee a day, the RR for the risk reduction of endometrial cancer was 0.75 (95% CI, 0.58-0.97) when compared with those who drank 1 cup or less. The association seemed largely confined to overweight and obese women, who showed a respective risk reduction of 12% (95% CI, 0-23%) and 20% (95% CI, 7-31%) for every cup of coffee, but was not observed among normal-weight women. There was a statistically significant interaction between coffee consumption and body mass index (p(interaction) < 0.001). These data indicate that coffee consumption may be associated with decreased risk of endometrial cancer, especially among women with excessive body weight. If confirmed by other prospective studies, these results are of major public health significance.

Food group intake and central obesity among children and adolescents in the Third National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVE

To explore mean food group intakes associated with central obesity anthropometry among children and adolescents enrolled in the Third National Health and Nutrition Examination Survey (NHANES III).

DESIGN

Cross-sectional study.

SETTING

Representative sampling of the US population (1998-2002).

SUBJECTS

Subjects were 3761 children (5-11 years) and 1803 adolescents (12-16 years) with single 24 h dietary recalls and anthropometric measures of central body fat (waist circumference and sum of subscapular and suprailiac skinfold thicknesses).

RESULTS

Results were controlled for confounding by age, height, race/ethnicity, Tanner stage, television viewing and parental education. In younger children, there was no relationship between central adiposity and mean intakes of dairy, fruit, vegetables or grains, while a positive association with meat intake was found among boys. In adolescent boys and girls, central body fat measures were inversely associated with mean dairy and grain intakes. Adolescent boys in the highest quartile of central adiposity consumed less fruit and fewer vegetables; those in the lowest central adiposity quartile consumed less meat. Finally, adolescents who met the criteria for central obesity (waist circumference >or=85th percentile for age and sex) reported consuming significantly less total dairy (as well as milk and cheese separately), total grains (whole and refined) and total fruit and vegetables. There was no association with meat consumption. To test the stability of these findings, the final analysis was replicated in 2541 same-aged adolescents from NHANES 1999-2002; the results were very similar.

CONCLUSIONS

These cross-sectional analyses suggest that intakes of dairy, grains and total fruits and vegetables are inversely associated with central obesity among adolescents.

Obesity-asthma association: is it explained by systemic oxidant stress?

BACKGROUND

The mechanism for the obesity-asthma association is unknown. This study evaluated the hypothesis that systemic oxidant stress explains this association.

METHODS

This cross-sectional study used year-20 follow-up evaluation data of 2,865 eligible participants in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. Current asthma was self-reported. Oxidant stress primarily was assessed by plasma F2-isoprostane concentrations. Obesity measures included categories of BMI and dual-energy x-ray absorptiometry-assessed fat mass index (FMI) and lean mass index (LMI). Logistic and linear regressions were used for analyses.

RESULTS

Asthma was associated with higher plasma F2-isoprostane concentrations (p = 0.049); however, this association was not significant when adjusted for either gender or BMI. The BMI-asthma association was seen only among women (p = 0.03; gender-specific interaction, p = 0.01), and this association was not explained by plasma F2-isoprostane levels. Similarly, both FMI and LMI were positively associated with asthma in women (p = 0.20 and 0.01, respectively). These associations also were not explained by plasma F2-isoprostane levels. Similar results were obtained when plasma levels of oxidized low-density lipoprotein were used instead of F2-isoprostane levels to study the BMI-asthma association at the year-15 evaluation.

CONCLUSIONS

Systemic oxidant stress, primarily assessed by plasma F2-isoprostane concentrations, was not independently associated with asthma and, therefore, may not explain the obesity-asthma association in women. The asthma-oxidant stress association is confounded by gender and obesity. This study is limited by the inability to measure airway oxidant stress. It is possible that another (as yet undetermined) measure of systemic oxidant stress may be more relevant in asthma.

Adiponectin multimers in maternal plasma

OBJECTIVE

Adiponectin is an anti-diabetic, anti-atherogenic, anti-inflammatory, and angiogenic adipokine that circulates in oligomeric complexes including: low molecular weight (LMW) trimers, medium molecular weight (MMW) hexamers, and high molecular weight (HMW) isoforms. The aim of this study was to determine whether there are changes in adiponectin multimers in pregnancy and as a function of maternal weight.

STUDY DESIGN

In this cross-sectional study, plasma concentrations of total, HMW, MMW, and LMW adiponectin were determined in women included in three groups: (1) normal pregnant women of normal body mass index (BMI) (n = 466), (2) overweight pregnant women (BMI >or=25; n = 257), and (3) non-pregnant women of normal weight (n = 40). Blood samples were collected once from each woman between 11 and 42 weeks of gestation. Plasma adiponectin multimer concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Non-parametric statistics were used for analysis.

RESULTS

(1) The median HMW adiponectin concentration and the median HMW/total adiponectin ratio were significantly higher, and the median LMW adiponectin concentration was significantly lower in pregnant women than in non-pregnant women. (2) Among pregnant women, the median plasma concentration of total, HMW, and MMW adiponectin was significantly higher in normal weight women than in overweight patients. (3) Maternal HMW was the most prevalent adiponectin multimer regardless of gestational age or BMI status. (4) There were no significant differences in the median concentration of total, MMW, and LMW adiponectin and their relative distribution with advancing gestation.

CONCLUSION

Human pregnancy is characterized by quantitative and qualitative changes in adiponectin multimers, especially the most active isoform, HMW adiponectin.

Influence of waist on adiponectin and insulin sensitivity in adolescence

It has been hypothesized that abdominal obesity leads to insulin resistance partly through decreased adiponectin. However, the cross-sectional and longitudinal associations among waist, adiponectin, and insulin sensitivity have not been examined in older adolescents. Non-Hispanic white and black children were recruited from the Minneapolis school district and underwent three examinations at mean ages 13, 15, and 19. Insulin sensitivity (measured using the gold-standard euglycemic clamp) and waist circumference were measured at all exams. Adiponectin was measured at mean ages 15 and 19. Partial correlations were used to examine associations among waist, adiponectin, and insulin sensitivity at mean age 15 (n = 308) and mean age 19 (n = 218). Longitudinal correlations and a longitudinal regression model were used to predict adiponectin and insulin sensitivity measured at ages 15 and 19, from age 13 waist and change in waist. At age 15, waist and adiponectin were significantly correlated (r = -0.32). At age 19, waist and adiponectin were significantly correlated (r = -0.36), as were waist and insulin sensitivity (r = -0.16). Both baseline waist and change in waist were significantly inversely associated with age 19 adiponectin but with age 19 insulin sensitivity only in men. In conclusion, in adolescents, the association between waist and adiponectin appears to develop several years before the association between waist and insulin sensitivity and there is a longitudinal association between waist and adiponectin. These results support the hypothesis that adiponectin may contribute to the association of waist and insulin sensitivity.

The addition of rosiglitazone to insulin in adolescents with type 1 diabetes and poor glycaemic control: a randomized-controlled trial

OBJECTIVE

To evaluate the effect of rosiglitazone, an insulin sensitizer, on glycaemic control and insulin resistance in adolescents with type 1 diabetes mellitus (T1DM) RESEARCH DESIGN AND METHODS: Randomized, double-blind, placebo-controlled crossover trial of rosiglitazone (4 mg twice daily) vs. placebo (24 wk each, with a 4 wk washout period). Entry criteria were diabetes duration >1 yr, age 10-18 yr, puberty (>or=Tanner breast stage 2 or testicular volume >4 mL), insulin dose >or=1.1 units/kg/day, and haemoglobin A1c (HbA1c) >8%. Responses to rosiglitazone were compared with placebo using paired t-tests.

RESULTS

Of 36 adolescents recruited (17 males), 28 completed the trial. At baseline, age was 13.6 +/- 1.8 yr, HbA1c 8.9 +/- 0.96%, body mass index standard deviation scores (BMI-SDS) 0.94 +/- 0.74 and insulin dose 1.5 +/- 0.3 units/kg/day. Compared with placebo, rosiglitazone resulted in decreased insulin dose (5.8% decrease vs. 9.4% increase, p = 0.02), increased serum adiponectin (84.8% increase vs. 26.0% decrease, p < 0.01), increased cholesterol (+0.5 mmol/L vs. no change, p = 0.02), but no significant change in HbA1c (-0.3 vs. -0.1, p = 0.57) or BMI-SDS (0.08 vs. 0.04, p = 0.31). Insulin sensitivity was highly variable in the seven subjects who consented to euglycaemic hyperinsulinaemic clamps. There were no major adverse effects attributable to rosiglitazone.

CONCLUSION

The addition of rosiglitazone to insulin did not improve HbA1c in this group of normal weight adolescents with T1DM.