Cord blood leptin levels in relation to child growth trajectories

OBJECTIVE

Leptin represents a potential modulator of developmental programming of childhood obesity. We investigated the association of cord blood leptin with growth trajectories from birth to early childhood.

MATERIALS/METHODS

We used data from the prospective mother-child cohort "Rhea", Crete, Greece. Cord blood samples from 642 neonates were collected. 578 (90%) children had complete follow up data from birth to 4years. We measured child weight, height, waist circumference, skinfold thicknesses, blood pressure, and serum lipids, leptin, adiponectin and C-reactive protein in early childhood (median 4.2years). We estimated growth trajectories from 3months up to 4years using random-effects linear-spline models. Multivariable logistic and linear regression models were used adjusting for confounders.

RESULTS

Mean cord blood leptin levels were 7.3ng/mL (standard deviation: 6.3). Children with high cord blood leptin (>90th percentile) exhibited lower weight, height and body mass index from 6months to early childhood. Each SD increase in cord blood leptin was associated with lower weight at the age of 4 by 242g (95% CI: -416, -69). In a stratified analysis, the reverse association was observed in children born small for gestational age (p for interaction=0.001), and in those exhibiting rapid infant growth during the first 3months of life (p for interaction=0.002). Cord blood leptin levels were not associated with cardiometabolic risk factors at 4years.

CONCLUSIONS

Long term programming effects of in utero exposure to leptin extends beyond infancy into early childhood. Further studies are needed to explore potential effect modification by intrauterine and early infancy growth patterns.

Hypovitaminosis D in bariatric surgery: A systematic review of observational studies

BACKGROUND

Obesity is a public health problem that carries global and substantial social and economic burden. Relative to non-surgical interventions, bariatric surgery has the most substantial and lasting impact on weight loss. However, it leads to a number of nutritional deficiencies requiring long term supplementation.

OBJECTIVES

The aims of this paper are to review 25-hydroxyvitamin D [25(OH)D] status pre and post bariatric surgery, describe the dose response of vitamin D supplementation, and assess the effect of the surgical procedure on 25(OH)D level following supplementation.

METHODS

We searched Medline, PubMed, the Cochrane Library and EMBASE, for relevant observational studies published in English, from 2000 to April 2015. The identified references were reviewed, in duplicate and independently, by two reviewers.

RESULTS

We identified 51 eligible observational studies assessing 25(OH)D status pre and/or post bariatric surgery. Mean pre-surgery 25(OH)D level was below 30ng/ml in 29 studies, and 17 of these studies showed mean 25(OH)D levels ≤20ng/ml. Mean 25(OH)D levels remained below 30ng/ml following bariatric surgery, despite various vitamin D replacement regimens, with only few exceptions. The increase in post-operative 25(OH)D levels tended to parallel increments in vitamin D supplementation dose but varied widely across studies. An increase in 25(OH)D level by 9-13ng/ml was achieved when vitamin D deficiency was corrected using vitamin D replacement doses of 1100-7100IU/day, in addition to the usual maintenance equivalent daily dose of 400-2000IU (total equivalent daily dose 1500-9100IU). There was no difference in mean 25(OH)D level following supplementation between malabsorptive/combination procedures and restrictive procedures.

CONCLUSION

Hypovitaminosisis D persists in obese patients undergoing bariatric surgery, despite various vitamin D supplementation regimens. Further research is needed to determine the optimal vitamin D dose to reach desirable 25(OH)D levels in this population, and to demonstrate whether this dose varies according to the surgical procedure.

In prostate cancer, low adiponectin levels are not associated with insulin resistance

PURPOSE

Adiponectin, an adipose tissue-derived hormone with insulin-sensitizing effect, has been inversely associated with several hormonally dependent malignancies. Prostate cancer is associated with low levels of adiponectin, which have been proposed as an independent risk factor for this malignancy. Aim of this study was to examine whether hypoadiponectinaemia in prostate is associated with insulin resistance.

EXPERIMENTAL DESIGN

Plasma samples and covariate data in the context of a case-control study of 300 Greek men were evaluated including 75 patients with prostate cancer, 75 patients with benign prostatic hyperplasia (BPH) and 150 age-matched healthy controls.

RESULTS

Patients with prostate cancer had significantly lower plasma adiponectin levels compared with the other two groups, that is BPH patients and healthy controls (7.4 ± 5 ng/mL vs. 11.5 ± 6.4 ng/mL and 12.8 ± 8 ng/mL, respectively). On the other hand, no statistically significant differences were found between patients with prostate cancer and the other two groups for both HOMA-IR and QUICKI (P-value = 0.551). As expected, in all three groups, the levels of adiponectin correlated negatively with HOMA-IR (rho = -0.214, P-value = 0.006), QUICKI (rho = 0.214, P-value = 0.006) and insulin levels (rho = 0.942, P-value < 0.001).

CONCLUSION

In spite of what would have been expected from the relevant literature, our data suggest that the hypoadiponectinaemia in prostatic cancer does not appear to be associated with insulin resistance.

20 years of leptin: role of leptin in human reproductive disorders

Leptin, as a key hormone in energy homeostasis, regulates neuroendocrine function, including reproduction. It has a permissive role in the initiation of puberty and maintenance of the hypothalamic-pituitary-gonadal axis. This is notable in patients with either congenital or acquired leptin deficiency from a state of chronic energy insufficiency. Hypothalamic amenorrhea is the best-studied, with clinical trials confirming a causative role of leptin in hypogonadotropic hypogonadism. Implications of leptin deficiency have also emerged in the pathophysiology of hypogonadism in type 1 diabetes. At the other end of the spectrum, hyperleptinemia may play a role in hypogonadism associated with obesity, polycystic ovarian syndrome, and type 2 diabetes. In these conditions of energy excess, mechanisms of reproductive dysfunction include central leptin resistance as well as direct effects at the gonadal level. Thus, reproductive dysfunction due to energy imbalance at both ends can be linked to leptin.

Can a selective PPARγ modulator improve glycemic control in patients with type 2 diabetes with fewer side effects compared with pioglitazone?

OBJECTIVE

INT131 besylate is a potent, nonthiazolidinedione, selective peroxisome proliferator-activated receptor γ (PPARγ) modulator (SPPARM) designed to improve glucose metabolism while minimizing the side effects of full PPARγ agonists. This placebo-controlled study compared the efficacy and side effects of INT131 besylate versus 45 mg pioglitazone HCl in subjects with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

This was a 24-week randomized, double-blind, placebo- and active-controlled study of 0.5-3.0 mg INT131 versus 45 mg pioglitazone or placebo daily in 367 subjects with T2D on sulfonylurea or sulfonylurea plus metformin. The primary efficacy analysis was the comparison of change from baseline to week 24 in hemoglobin A1c (HbA1c) across treatment groups. Fluid status was assessed with a prospective scoring system for lower-extremity pitting edema.

RESULTS

INT131 had a steep dose response for efficacy as measured by changes in HbA1c. After 24 weeks' treatment, the 0.5-mg dose demonstrated minimal efficacy (HbA1c -0.3 ± 0.12%) and the 2-mg dose demonstrated near-maximal efficacy (HbA1c -1.1 ± 0.12%), which was not statistically different from the efficacy of 45 mg pioglitazone (HbA1c -0.9 ± 0.12%; P < 0.01 for noninferiority). With the 1-mg dose, INT131 provided significant improvements in glycemic control (HbA1c 0.8 ± 0.12; P < 0.001 vs. placebo) but with less edema, weight gain, and hemodilution than observed with 45 mg pioglitazone.

CONCLUSIONS

INT131 demonstrated dose-dependent reductions in HbA1c, equivalent to 45 mg pioglitazone, but with less fluid accumulation and weight gain, consistent with its SPPARM design.

Abstract 453: Chemerin and Resistin Expression in Carotid Plaque Instability

Objective: Chemerin and resistin are pro-inflammatory cytokines that have been shown to play a role in atherosclerosis and coronary artery disease. However, their association with carotid atherosclerosis has not been investigated. We sought to assess the relationship between a) circulating chemerin/resistin levels and cerebrovascular symptomatology, and b) chemerin/resistin plaque expression and carotid plaque instability.

Methods: Patients scheduled for carotid endarterectomy were recruited from the Royal Victoria and Jewish General hospitals, Montreal, Canada. Blood was drawn pre-operatively and plasma resistin and chemerin were measured using ELISA. Maximum stenosis sections were stained with hematoxylin and eosin and immunostained with anti-CD3 and anti-CD68. Two vascular pathologists used semi-quantitative scales to classify plaque foam cells and inflammatory cells as well as overall plaque instability. RNA was isolated from the area of maximum stenosis, reverse transcribed, and qPCR was performed to measure chemerin and resistin expression. Kruskal-Wallis or Mann-Whitney U tests were used to evaluate differences in resistin and chemerin between groups.

Results: In this ongoing study we recruited 169 patients (66.1% men, 74.5% symptomatic) with a mean±SD age of 70.0±9.3 years. To date all 169 patients had blood samples drawn and 100 had plaque chemerin and resistin expression assessed. Symptomatic patients had higher plasma chemerin (230 (179.0-261.3) vs. 201.4 (175.8-228.1) ng/ml, P=0.08) and resistin levels (12.7 (10.2-17.7) vs. 10.8 (7.1-16.0) ng/ml, P=0.02) when compared with asymptomatic patients. Chemerin plaque expression was decreased in plaques with greater number of foam cells and inflammatory cells and in plaques with greater overall instability. Resistin plaque expression was also decreased in plaques with a greater number of foam cells and inflammatory cells.

Conclusions: Circulating chemerin and resistin levels are increased in symptomatic patients. Intraplaque chemerin and resistin expression is inversely related to the number of plaque inflammatory cells and instability. Our ongoing work will determine the underlying mechanisms linking chemerin and resistin with atherosclerotic plaque instability.

Abstract 124: Association of AdipoR2 mRNA Expression on Peripheral Monocytes With Carotid Plaque Instability

Adiponectin, an adipose tissue secreted protein, possesses anti-atherosclerotic properties. Its effects are partly mediated through its action on monocytes, via receptors, AdipoR1 and AdipoR2. Circulating monocytes play a crucial role both in plaque initiation and in the progression of atherosclerosis. The aim of this ongoing study is to investigate for the first time whether there is differential expression of AdipoR1/AdipoR2 on human peripheral monocytes in patients with unstable vs. stable carotid atherosclerotic plaques.

Patients (n=20) with carotid stenosis of ≥50% scheduled for a carotid endarterectomy (CEA) were recruited from the Royal Victoria Hospital, Montreal, Canada. Blood samples were collected the morning of the CEA. A radioimmunoassay was used for plasma total adiponectin measurement. Circulating monocytes were isolated from mononuclear cells using a Magnetic Cell-Sorting technique with CD14+ Human Microbeads. Expression of AdipoR1/AdipoR2 mRNA on peripheral monocytes was determined using quantitative RT-PCR. Carotid plaque specimens were processed for histological analyses. Plaque instability was categorized according to the gold standard American Heart Association classification.

All specimens were graded as either a Type V (n=11) or a Type VI plaque (n=9). Type VI represents a more unstable lesion than Type V. AdipoR2 gene expression on monocytes was inversely associated with greater plaque instability; compared to patients with a Type V plaque, those with a Type VI plaque had 1.88-fold decreased AdipoR2 mRNA levels (p=0.046). AdipoR2 gene expression was found to be a trending predictor of a Type VI plaque (OR=2.93; 95% CI=0.87-9.81; p=0.082). AdipoR1 gene expression on monocytes did not differ between the two groups, while plasma adiponectin levels were lower in Type VI plaques (Type VI: 2.73 [2.19-3.96] μg/ml vs. Type V: 6.97 [4.69-10.07] μg/ml; p= 0.067). Plasma adiponectin levels did not correlate with the expression levels of AdipoR1/AdipoR2 on monocytes.

These results indicate that carotid plaque instability is associated with decreased AdipoR2 expression on peripheral monocytes. Our ongoing study may determine the underlying mechanisms linking adiponectin and its receptors with plaque instability.

Cohort profile: project viva

We established Project Viva to examine prenatal diet and other factors in relation to maternal and child health. We recruited pregnant women at their initial prenatal visit in eastern Massachusetts between 1999 and 2002. Exclusion criteria included multiple gestation, inability to answer questions in English, gestational age ≥22 weeks at recruitment and plans to move away before delivery. We completed in-person visits with mothers during pregnancy in the late first (median 9.9 weeks of gestation) and second (median 27.9 weeks) trimesters. We saw mothers and children in the hospital during the delivery admission and during infancy (median age 6.3 months), early childhood (median 3.2 years) and mid-childhood (median 7.7 years). We collected information from mothers via interviews and questionnaires, performed anthropometric and neurodevelopmental assessments and collected biosamples. We have collected additional information from medical records and from mailed questionnaires sent annually to mothers between in-person visits and to children beginning at age 9 years. From 2341 eligible women, there were 2128 live births; 1279 mother-child pairs provided data at the mid-childhood visit. Primary study outcomes include pregnancy outcomes, maternal mental and cardiometabolic health and child neurodevelopment, asthma/atopy and obesity/cardiometabolic health. Investigators interested in learning more about how to obtain Project Viva data can contact Project_Viva@hphc.org.

Early growth and development of later life metabolic disorders

Growth is effected via a complex interaction of genetic, nutritional, environmental and growth factors. Hormonal factors such as the growth hormone (GH) and insulin-like growth factor (IGF) signaling system, the human placental lactogen, and insulin play an integral role in early growth. Genetic factors affecting the GH-IGF system and insulin secretion and actions, and epigenetic mechanisms including DNA methylation have been further implicated as contributory factors. These hormonal systems, on a background of genetic susceptibility, together with other factors including maternal nutrition, placental and environmental factors, regulate not only early growth but also development. These interactions may impact on later health consequences in adult life. Accumulating data in the last few decades on developmental programming and later life metabolic disorders has provided a novel perspective on the possible pathogenesis of metabolic dysregulation. Despite postulations put forward to elucidate the mechanism underlying the association between early growth and later life metabolic disorders, it remains unclear what the dominant factor(s) would be, how any underlying mechanisms interact, or whether these mechanisms are truly causal.

Abstract 511: Total Circulating Adiponectin Levels and its Receptors are Associated with Histological and Immunohistochemical Features of Carotid Plaque Instability

Introduction.

Evidence shows that low plasma levels of adiponectin, a vasculoprotective adipokine, are associated with coronary artery disease and carotid-intima media thickness. The current study investigated for the first time the association between adiponectin and carotid plaque instability, namely the association between circulating adiponectin, expression of its receptors (AR1/AR2), and plaque instability as assessed by histology/immunohistochemistry.

Methods.

100 patients scheduled for carotid endarterectomy were recruited from the Royal Victoria Hospital, Montreal. Blood samples were collected to determine total adiponectin levels. Carotid plaque specimens were stained with hematoxylin and eosin and immunostained for CD3 (lymphocytes), CD68 (macrophages/foam cells), von Willebrand Factor (vWF, neovascularization), and AR1/AR2. A vascular pathologist categorized the plaques according to AHA classification and with a semi-quantitative scale of plaque instability. The intensity and percentage of macrophages/foam cells stained with AR1/AR2 were assessed using an optical microscope scoring method.

Results.

Patients with less infiltration of CD68+ inflammatory cells in their plaques had higher levels of total circulating adiponectin (12.26 + 6.74 μg/ml) when compared to patients with greater infiltration (8.99 + 6.97 μg/ml; p=0.010). The intensity of AR1 expression on macrophages was directly associated with overall grade of inflammation and neovascularization (p=0.025 and p=0.05 respectively). A trending inverse association was noted between the percentage of macrophages expressing AR1 and overall stability (p=0.084). Expression of vWF was inversely associated with the percentage of macrophages and foam cells expressing AR2 (p=0.033 and p=0.002, respectively), while increase cap infiltration was detected in plaques with a lower intensity of AR2 expression (p=0.013).

Conclusion.

Patients whose plaques were characterized as unstable were found to have lower plasma levels of total adiponectin, a higher expression of AR1 and a lower expression of AR2 in their plaques. These results suggest a potential role for adiponectin in the development of plaque instability, as well as differential roles for its two receptors.

Adiponectin pathway polymorphisms and risk of breast cancer in African Americans and Hispanics in the Women's Health Initiative

Adiponectin, a protein secreted by the adipose tissue, is an endogenous insulin sensitizer with circulating levels that are decreased in obese and diabetic subjects. Recently, circulating levels of adiponectin have been correlated with breast cancer risk. Our previous work showed that polymorphisms of the adiponectin pathway are associated with breast cancer risk. We conducted the first study of adiponectin pathways in African Americans and Hispanics in the Women's Health Initiative SNP Health Association Resource cohort of 3,642 self-identified Hispanic women and 8,515 self-identified African American women who provided consent for DNA analysis. Single nucleotide polymorphisms (SNPs) from three genes were included in this analysis: ADIPOQ, ADIPOR1, and ADIPOR2. The genome-wide human SNP array 6.0 (909,622 SNPs) ( www.affymetrix.com ) was used. We found that rs1501299, a functional SNP of ADIPOQ that we previously reported was associated with breast cancer risk in a mostly Caucasian population, was also significantly associated with breast cancer incidence (HR for the GG/TG genotype: 1.23; 95 % CI 1.059-1.43) in African American women. We did not find any other SNPs in these genes to be associated with breast cancer incidence. This is the first study assessing the role of adiponectin pathway SNPs in breast cancer risk in African Americans and Hispanics. RS1501299 is significantly associated with breast cancer risk in African American women. As the rates of obesity and diabetes increase in African Americans and Hispanics, adiponectin and its functional SNPs may aid in breast cancer risk assessment.

Selective PPARγ modulator INT131 normalizes insulin signaling defects and improves bone mass in diet-induced obese mice

INT131 is a potent non-thiazolidinedione (TZD)-selective peroxisome proliferator-activated receptor-γ modulator being developed for the treatment of type 2 diabetes. In preclinical studies and a phase II clinical trial, INT131 has been shown to lower glucose levels and ameliorate insulin resistance without typical TZD side effects. To determine whether the insulin-sensitizing action of INT131 is mediated by effects on insulin-mediated glucose homeostasis and insulin signaling, high-fat diet-induced obese (DIO) insulin-resistant mice treated with INT131 were studied. INT131's effects on bone density were also investigated. Treatment with INT131 enhanced systemic insulin sensitivity, as revealed by lower insulin levels in the fasted state and an increase in the area above the curve during an insulin tolerance test. These effects were independent of changes in adiposity. Insulin-stimulated PI3K activity in skeletal muscle and adipose tissue of DIO mice was significantly reduced ∼50-65%, but this was restored completely by INT131 therapy. The INT131 effects on PI3K activity are most likely due to increased IRS-1 tyrosine phosphorylation. Concurrently, insulin-mediated Akt phosphorylation also increased after INT131 treatment in DIO mice. Importantly, INT131 therapy caused a significant increase in bone mineral density without alteration in circulating osteocalcin in these mice. These data suggest that a newly developed insulin-sensitizing agent, INT131, normalizes obesity-related defects in insulin action on PI3K signaling in insulin target tissues by a mechanism involved in glycemic control. If these data are confirmed in humans, INT131 could be used for treating type 2 diabetes without loss in bone mass.

Polymorphisms of ADIPOQ and ADIPOR1 and prostate cancer risk

Studies have linked prostate cancer risk with insulin resistance and obesity. Circulating levels of adiponectin, a protein involved in insulin resistance and obesity, have been associated with prostate cancer risk. We studied the association of prostate cancer risk with haplotype tagging single nucleotide polymorphisms (SNPs) of the adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) chosen based on their functional relevance or association with other types of cancer. DNA samples from 465 cases and 441 healthy volunteers from New York City were genotyped for ADIPOQ rs266729, rs822395, rs822396, rs1501299, and rs2241766 SNPs and ADIPOR1 rs12733285, rs1342387, rs7539542, rs2232853, and rs10920531 SNPs. We performed both single- and multiple-SNP analyses. We found that rs12733285, rs7539452, rs266729, rs822395, rs822396, and rs1501299 were significantly associated with prostate cancer risk. Haplotype analysis confirmed these results and identified 5 ADIPOQ 4-SNP haplotypes and 1 ADIPOR1 2-SNP haplotype tightly associated with prostate cancer risk. Importantly, 2 ADIPOQ SNPs, rs266729 and rs1501299, have been previously associated with colon and breast cancer risk, respectively, in the same direction as in this study. These findings suggest that variants of the adiponectin pathway may be associated with susceptibility to various forms of common cancers and warrant validation studies.

The role of the fat mass and obesity associated gene (FTO) in breast cancer risk

BACKGROUND

Obesity has been shown to increase breast cancer risk. FTO is a novel gene which has been identified through genome wide association studies (GWAS) to be related to obesity. Our objective was to evaluate tissue expression of FTO in breast and the role of FTO SNPs in predicting breast cancer risk.

METHODS

We performed a case-control study of 354 breast cancer cases and 364 controls. This study was conducted at Northwestern University. We examined the role of single nucleotide polymorphisms (SNPs) of intron 1 of FTO in breast cancer risk. We genotyped cases and controls for four SNPs: rs7206790, rs8047395, rs9939609 and rs1477196. We also evaluated tissue expression of FTO in normal and malignant breast tissue.

RESULTS

We found that all SNPs were significantly associated with breast cancer risk with rs1477196 showing the strongest association. We showed that FTO is expressed both in normal and malignant breast tissue. We found that FTO genotypes provided powerful classifiers to predict breast cancer risk and a model with epistatic interactions further improved the prediction accuracy with a receiver operating characteristic (ROC) curves of 0.68.

CONCLUSION

In conclusion we have shown a significant expression of FTO in malignant and normal breast tissue and that FTO SNPs in intron 1 are significantly associated with breast cancer risk. Furthermore, these FTO SNPs are powerful classifiers in predicting breast cancer risk.

Duration of lactation and maternal adipokines at 3 years postpartum

OBJECTIVE

Lactation has been associated with reduced maternal risk of type 2 diabetes, the metabolic syndrome, and cardiovascular disease. We examined the relationship between breastfeeding duration and maternal adipokines at 3 years postpartum.

RESEARCH DESIGN AND METHODS

We used linear regression to relate the duration of lactation to maternal leptin, adiponectin, ghrelin, and peptide YY (PYY) at 3 years postpartum among 570 participants with 3-year postpartum blood samples (178 fasting), prospectively collected lactation history, and no intervening pregnancy in Project Viva, a cohort study of mothers and children.

RESULTS

A total of 88% of mothers had initiated breastfeeding, 26% had breastfed ≥ 12 months, and 42% had exclusively breastfed for ≥ 3 months. In multivariate analyses, we found that duration of total breastfeeding was directly related to PYY and ghrelin, and exclusive breastfeeding duration was directly related to ghrelin (predicted mean for never exclusively breastfeeding: 790.6 pg/mL vs. ≥ 6 months of exclusive breastfeeding: 1,008.1 pg/mL; P < 0.01) at 3 years postpartum, adjusting for pregravid BMI, gestational weight gain, family history of diabetes, parity, smoking status, and age. We found a nonlinear pattern of association between exclusive breastfeeding duration and adiponectin in multivariate-adjusted models.

CONCLUSIONS

In this prospective cohort study, we found a direct relationship between the duration of lactation and both ghrelin and PYY at 3 years postpartum.

Gestational glucose tolerance and cord blood leptin levels predict slower weight gain in early infancy

OBJECTIVE

To determine the extent to which known prenatal and perinatal predictors of childhood obesity also predict weight gain in early infancy.

STUDY DESIGN

We studied 690 infants participating in the prospective cohort Project Viva. We measured length and weight at birth and at 6 months. Using multivariable linear regression, we examined relationships of selected maternal and infant factors with change in weight-for-length z-score (WFL-z) from 0 to 6 months.

RESULTS

Mean (standard deviation) change in WFL-z from 0 to 6 months was 0.23 (1.11), which translates to 4500 grams gained from birth to 6 months of life in an infant with average birth weight and length. After adjustment for confounding variables and birth weight-for-gestational age z-score (-0.28 [95% confidence interval, -0.37, -0.19] per unit), cord blood leptin (-0.40 [95%confidence interval, -0.61, -0.19] per 10 ng/mL), and gestational diabetes -0.50 [95%confidence interval, -0.88, -0.11] versus normal glucose tolerance)were each associated with slower gain in WFL-z from 0 to 6 months.

CONCLUSIONS

Higher neonatal leptin and gestational diabetes predicted slower weight gain in the first 6 months of life. The hormonal milieu of the intrauterine environment may determine growth patterns in early infancy and thus later obesity.

Low testosterone levels predict all-cause mortality and cardiovascular events in women: a prospective cohort study in German primary care patients

OBJECTIVE

Although associations between testosterone and cardiovascular (CV) morbidity in women have been proposed, no large prospective study has evaluated potential associations between testosterone and mortality in women. The objective was to determine whether baseline testosterone levels in women are associated with future overall or CV morbidity and mortality.

DESIGN

Prospective cohort study with a 4.5-year follow-up period.

METHODS

From a representative sample of German primary care practices, 2914 female patients between 18 and 75 years were analyzed for the main outcome measures: CV risk factors, CV diseases, and all-cause mortality.

RESULTS

At baseline, the study population was aged 57.96±14.37 years with a mean body mass index of 26.71±5.17 kg/m(2). No predictive value of total testosterone for incident CV risk factors or CV diseases was observed in logistic regressions. Patients with total testosterone levels in the lowest quintile Q1, however, had a higher risk to die of any cause or to develop a CV event within the follow-up period compared to patients in the collapsed quintiles Q2-Q5 in crude and adjusted Cox regression models (all-cause mortality: Q2-Q5 versus Q1: crude hazard ratios (HR) 0.49, 95% confidence interval (CI) 0.33-0.74; adjusted HR 0.62, 95% CI 0.42-0.939; CV events: Q2-Q5 versus Q1: crude HR 0.54, 95% CI 0.38-0.77; adjusted HR 0.68, 95% CI 0.48-0.97). Kaplan-Meier curves revealed similar data.

CONCLUSIONS

Low baseline testosterone in women is associated with increased all-cause mortality and incident CV events independent of traditional risk factors.

Lipid and inflammatory biomarkers and kidney function decline in type 2 diabetes

AIMS/HYPOTHESIS

Potentially modifiable biomarkers may influence the decline in estimated GFR (eGFR), but few data are currently available in type 2 diabetic adults.

METHODS

We studied 516 women with type 2 diabetes in the Nurses' Health Study with data on lipid and inflammatory biomarkers from plasma collected in 1989 and plasma creatinine in samples collected in 1989 and 2000. An estimated GFR decline of >or=25% over 11 years was the outcome of interest.

RESULTS

Comparing the highest with the lowest quartile, soluble tumour necrosis factor receptor 2 (sTNFR-2) was independently associated with an eGFR decline of >or=25% (multivariate OR 5.81; 95% CI 2.90-11.65); this association was stronger in obese women (OR 16.76; 95% CI 4.69-59.90 for BMI >or=30 kg/m(2); OR 2.78, 95% CI 1.12-6.89 for BMI <30 kg/m(2); p for interaction = 0.02). No lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, non-HDL-cholesterol, triacylglycerols, lipoprotein(a), or apolipoprotein B) or other markers of inflammation (C-reactive protein, fibrinogen, E-selectin, intracellular cell adhesion molecule 1, leptin or adiponectin) were significantly associated with eGFR decline after multivariable adjustment.

CONCLUSIONS/INTERPRETATION

Elevated sTNFR-2 levels may be an important and potentially modifiable risk factor for eGFR decline in type 2 diabetes, especially in those with a BMI of >or=30 kg/m(2).

Regular consumption of nuts is associated with a lower risk of cardiovascular disease in women with type 2 diabetes

Higher nut consumption has been associated with lower risk of coronary heart disease (CHD) events in several epidemiologic studies. The study examined the association between intake of nuts and incident cardiovascular disease (CVD) in a cohort of women with type 2 diabetes. For the primary analysis, there were 6309 women with type 2 diabetes who completed a validated FFQ every 2-4 y between 1980 and 2002 and were without CVD or cancer at study entry. Major CVD events included incident myocardial infarction (MI), revascularization, and stroke. During 54,656 person-years of follow-up, there were 452 CHD events (including MI and revascularization) and 182 incident stroke cases. Frequent nut and peanut butter consumption was inversely associated with total CVD risk in age-adjusted analyses. After adjustment for conventional CVD risk factors, consumption of at least 5 servings/wk of nuts or peanut butter [serving size, 28 g (1 ounce) for nuts and 16 g (1 tablespoon) for peanut butter] was significantly associated with a lower risk of CVD (relative risk = 0.56; 95% CI: 0.36-0.89). Furthermore, when we evaluated plasma lipid and inflammatory biomarkers, we observed that increasing nut consumption was significantly associated with a more favorable plasma lipid profile, including lower LDL cholesterol, non-HDL cholesterol, total cholesterol, and apolipoprotein-B-100 concentrations. However, we did not observe significant associations for HDL cholesterol or inflammatory markers. These data suggest that frequent nut and peanut butter consumption is associated with a significantly lower CVD risk in women with type 2 diabetes.

Variants of the adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) genes and colorectal cancer risk

CONTEXT

Current epidemiological evidence suggests an association between obesity, hyperinsulinemia, and colorectal cancer risk. Adiponectin is a hormone secreted by the adipose tissue, and serum levels are inversely correlated with obesity and hyperinsulinemia. While there is evidence of an association between circulating adiponectin levels and colorectal cancer risk, no association between genes of the adiponectin pathway and colorectal cancer have been reported to date.

OBJECTIVE

To determine the association of 10 haplotype-tagging single-nucleotide polymorphisms (SNPs) of the adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) genes with colorectal cancer risk.

DESIGN, SETTING, AND PATIENTS

Two case-control studies including patients with a diagnosis of colorectal cancer and controls were recruited between 2000 and 2007. Case-control study 1 included a total of 441 patients with a diagnosis of colorectal cancer and 658 controls; both groups were of Ashkenazi Jewish ancestry and from New York, New York. Case-control study 2 included 199 patients with a diagnosis of colorectal cancer and 199 controls from Chicago, Illinois, matched 1:1 for sex, age, and ethnicity.

MAIN OUTCOME MEASURES

ADIPOQ and ADIPOR1 SNP frequency among cases and controls.

RESULTS

In study 1, after adjustment for age, sex, and SNPs from the same gene, 3 ADIPOQ SNPs and 1 ADIPOR1 SNP were associated with colorectal cancer risk: rs266729 (adjusted odds ratio [AOR], 0.72; 95% confidence interval [CI], 0.55-0.95) and rs822396 (AOR, 0.37; 95% CI, 0.14-1.00) were associated with decreased risk whereas rs822395 (AOR, 1.76; 95% CI, 1.09-2.84) and rs1342387 (AOR, 1.79; 95% CI, 1.18-2.72) were associated with increased risk. In study 2, after adjustment for age, sex, race, and SNPs from the same gene, the ADIPOQ SNP rs266729 was associated with a decreased colorectal cancer risk of similar magnitude as in study 1 (AOR, 0.52; 95% CI, 0.34-0.78). Combined analysis of both studies shows an association of rs266729 with decreased colorectal cancer risk (AOR, 0.73; 95% CI, 0.53-0.99).

CONCLUSION

The SNP rs266729, which tags the 5' flanking region of the ADIPOQ gene, is associated with decreased colorectal cancer risk.

Relationship between serum adiponectin and prostate cancer grade

BACKGROUND

Obesity is associated with prostate cancer (PCA) grade, but the mechanism behind this relationship is not understood. Adiponectin is an adipokine that has been linked with the development of hormonally sensitive carcinomas, including prostate cancer. We evaluated the relationship between serum adiponectin and Gleason score (GS) in a prospective series of patients seen in a single institution.

METHODS

Localized PCA patients evaluated at Dana-Farber Cancer Institute between 2001 and 2005 who enrolled in a prospective serum banking protocol were eligible for this study. Patients with prior hormonal therapy and/or metastatic disease were excluded. High-grade disease was defined as biopsy or radical prostatectomy (RP) GS of 7 or higher. Logistic regression models were used to assess the relationship between high-grade disease and adiponectin levels while adjusting for other potential prognostic variables.

RESULTS

There were 539 patients included in this study, of whom 199 had undergone RP. Median age was 60 years. Median PSA was 5.1 ng/dl. Biopsy GS of 7 or higher was seen in 46.9% of patients. For biopsy GS, higher PSA, older age, and higher BMI were significantly associated with increased odds of GS 7 or higher, but adiponectin was not. In men undergoing RP, there was a significant inverse relationship between pathologic GS and adiponectin dichotomized at the median, due to a significantly higher rate of upgrading in patients with lower adiponectin (P = 0.014).

CONCLUSIONS

Although there was no association between biopsy GS and adiponectin, in patients who had undergone RP, lower adiponectin was independently associated with high-grade prostate cancer.

Variants of the adiponectin and adiponectin receptor 1 genes and breast cancer risk

Breast cancer risk is higher among obese women and women with diabetes. Adiponectin is a protein exclusively secreted by adipose tissue, circulating levels of which have been associated with breast cancer risk. Whether genetic variants within the adiponectin pathway are associated with breast cancer risk is unknown. To explore the association of genetic variants of the adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) genes with breast cancer risk, we conducted a case control study of female patients with breast cancer and healthy female controls from New York City recruited between 1999 and 2004. We genotyped 733 hospital-based breast cancer cases and 839 controls for 10 haplotype-tagging single nucleotide polymorphisms (SNP) of ADIPOQ and ADIPOR1. Two ADIPOQ SNPs (rs2241766 and rs1501299), which have been associated with circulating levels of adiponectin, were associated with breast cancer risk [rs1501299*GG: odd ratios (OR), 1.80; 95% confidence interval (95% CI), 1.14-2.85; rs2241766*TG: OR, 0.61; 95% CI, 0.46-0.80]. One ADIPOR1 SNP (rs7539542), which modulates expression of adiponectin receptor 1 mRNA, was also associated with breast cancer risk (OR, 0.51; 95% CI, 0.28-0.92). Based on the known function of rs2241766 and rs1501299, we categorized individuals by adiponectin signaling status and found that, when compared with high signalers, intermediate signalers had a 4.16-fold increase in breast cancer risk (95% CI, 0.49-35.19), and low signalers had a 6.56-fold increase in breast cancer risk (95% CI, 0.78-54.89; P(trend) = 0.001). This is the first report of an association between functionally relevant variants of the adiponectin pathway and breast cancer risk. The results warrant further studies of the adiponectin pathway in breast cancer.

A phase II study of mifepristone (RU-486) in castration-resistant prostate cancer, with a correlative assessment of androgen-related hormones

OBJECTIVE

To evaluate mifepristone (RU-486) in patients with castration-resistant prostate cancer (CRPC), with a correlative assessment of serum androgens and androgen metabolites

PATIENTS AND METHODS

The androgen receptor (AR) is critical in the development and progression of prostate cancer, but available antiandrogens incompletely abrogate AR signalling. Mifepristone is a potent AR antagonist that functions by competing with androgen, preventing AR coactivator binding and by enhancing binding of AR corepressors. Patients with CRPC were treated with mifepristone 200 mg/day oral until disease progression. Testosterone, dihydrotestosterone (DHT), androstenedione, dihydroepiandrosterone sulphate and the testosterone metabolite 3 alpha-diol G, were measured at baseline and during therapy.

RESULTS

Nineteen patients were enrolled between April and August 2005; they were treated for a median (range) of 85 (31-338) days. The median prostate-specific antigen (PSA) level at enrollment was 22.0 (3.0-937.2) ng/mL. No patient had a PSA response (>50% reduction in PSA). Six patients had stable disease for a median of 5.5 months. After 1 month, adrenal androgens were increased and testosterone and DHT increased by 91% and 80%, respectively, compared to baseline.

CONCLUSION

Mifepristone had limited activity in patients with CRPC, and stimulated a marked increase in adrenal androgens, testosterone and DHT. We hypothesise that inhibition of glucocorticoid receptor by mifepristone resulted in an increase in adrenocorticotropic hormone and subsequent increase in adrenal androgens, and that their conversion by tumour cells to testosterone and DHT probably limited the efficacy of mifepristone. These data emphasize the continued importance of alternative androgen sources in AR signalling in CRPC.

Relationship of plasma adiponectin with sex hormone and insulin-like growth factor levels

OBJECTIVE

Recent studies have suggested that a relationship between adiponectin and sex hormone, prolactin, and insulin-like growth factor levels could be important for breast cancer risk and insulin sensitivity. Therefore, we assessed the relationship of adiponectin with plasma concentrations of estrone; estradiol; estrone sulfate; testosterone; androstenedione; dehydroepiandrosterone (DHEA); dehydroepiandrosterone sulfate (DHEAS); sex hormone binding globulin (SHBG); prolactin; insulin-like growth factor (IGF-1); its binding protein, IGF binding protein 3 (IGFBP-3); c-peptide; and IGF binding protein 1 (IGFBP-1) among 360 postmenopausal women not taking postmenopausal hormones from the Nurses' Health Study.

RESEARCH METHODS AND PROCEDURES

Multivariate models were adjusted for physical activity, alcohol consumption, age at blood draw, age at first birth/parity, fasting status, and time of day of blood draw; a separate model was additionally adjusted for BMI at blood draw.

RESULTS

Estrogens were inversely associated with adiponectin levels; however, except for free estradiol, these associations were substantially attenuated after adjustment for BMI. Free estradiol levels were 27% lower among women in the top vs. bottom quartile of adiponectin levels. No consistent associations were observed for the androgens, prolactin, IGF-1, and IGFBP-3. However, SHBG, c-peptide, and IGFBP-1 were strongly and independently associated with adiponectin levels (r = 0.29, -0.30, 0.24, respectively).

CONCLUSION

With the exceptions of SHBG, c-peptide, and IGFBP-1, the studied analytes were modestly associated with adiponectin and the associations were, in large part, mediated by body fat.

Impact of physical activity on insulin levels in breast cancer survivors

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Background: Accumulating data suggest that body weight and physical activity may affect breast cancer risk and outcomes. Biological mechanisms underlying these relationships are not clear. Studies have demonstrated that high levels of insulin, often seen in obese and sedentary individuals, are also associated with an increased risk of breast cancer recurrence and breast cancer-related death. We sought to analyze whether exercise lowers insulin levels in a population of breast cancer survivors. Methods: Inactive women with early stage breast cancer who had completed adjuvant treatment were randomized to a 16 week, mixed cardiovascular and strength training exercise intervention, or to a normal care control group. Target exercise goals included 2 supervised strength training sessions and 90 minutes of unsupervised cardiovascular exercise each week. Fasting insulin and glucose levels, as well as measurement of weight, body composition, and circumference at the waist and hip, were collected at baseline and after 16 weeks in both groups, and changes in these measures were assessed. Results: One hundred and one women were randomized. Comparison of changes in anthropometric measures are presented in Table 1 . Baseline insulin levels were similar in the 2 groups. After the 16-week exercise or control period, insulin levels decreased by 2.86 μIU/ml in the exercise group (p=0.03), and by 0.27 μIU/ml in the control group (p=0.65). A comparison of the change in insulin levels across time in the 2 groups approached statistical significance (p=0.07). There was also a trend toward improvements in insulin sensitivity in the exercise group (p=0.09), with no change seen in fasting glucose levels. Conclusions: Physical activity was associated with a decrease in insulin levels and in hip circumference in breast cancer survivors. The relationship between physical activity and breast cancer prognosis may be mediated, at least partially, through changes in insulin levels and/or changes in fat mass or deposition.

[Table: see text]

No significant financial relationships to disclose.

Linking hepatic transcriptional changes to high-fat diet induced physiology for diabetes-prone and obese-resistant mice

Insulin resistance is characterized by high insulin levels and decreased responsiveness of tissues to the clearance of glucose from the bloodstream. This study maintained the diabetes-prone C57BL/6J and obese-resistant A/J mice strains on a high-fat diet for twelve weeks to transcriptionally profile the liver for changes caused by high fat diet. In the eighth week of the experiment, the C57BL/6J mice began exhibiting signs of insulin resistance, while the A/J mice did not show any such indications during the course of the experiment. A regression model of partial least squares between serum insulin measurements and the liver gene expression profile for the C57BL/6J mice on a high-fat diet was constructed in an effort to quantitatively link the physiological measurement with the gene expressions. A series of discriminating genes between high fat and chow fed mice was generated for both the C57BL/6J and A/J strains. These discriminatory genes contain information about the mechanisms responsible for the development of insulin resistance, and the compensation for a high fat diet, respectively. The results identified several genes involved in the development of insulin resistance and serve as a framework for other studies involving other organs affected by this systemic disease.

Peroxisome proliferator activator receptor gamma coactivator-1 expression is reduced in obesity: potential pathogenic role of saturated fatty acids and p38 mitogen-activated protein kinase activation

Peroxisome proliferator activator receptor-gamma coactivator 1 (PGC-1) is a major candidate gene for diabetes-related metabolic phenotypes, contributing to decreased expression of nuclear-encoded mitochondrial genes in muscle and adipose tissue. We have demonstrated that muscle expression of PGC-1alpha and -beta is reduced in both genetic (Lep(ob)/Lep(ob)) and acquired obesity (high fat diet). In C57BL6 mice, muscle PGC-1alpha expression decreased by 43% (p < 0.02) after 1 week of a high fat diet and persisted more than 11 weeks. In contrast, PGC-1alpha reductions were not sustained in obesity-resistant A/J mice. To identify mediators of obesity-linked reductions in PGC-1, we tested the effects of cellular nutrients in C2C12 myotubes. Although overnight exposure to high insulin, glucose, glucosamine, or amino acids had no effect, saturated fatty acids potently reduced PGC-1alpha and -beta mRNA expression. Palmitate decreased PGC-1alpha and -beta expression by 38% (p = 0.01) and 53% (p = 0.006); stearate similarly decreased expression of PGC-1alpha and -beta by 22% (p = 0.02) and 39% (p = 0.02). These effects were mediated at a transcriptional level, as indicated by an 11-fold reduction of PGC-1alpha promoter activity by palmitate and reversal of effects by histone deacetylase inhibition. Palmitate also (a) reduced expression of tricarboxylic acid cycle and oxidative phosphorylation mitochondrial genes and (b) reduced oxygen consumption. These effects were reversed by overexpression of PGC-1alpha or -beta, indicating PGC-1 dependence. Palmitate effects also required p38 MAPK, as demonstrated by 1) palmitate-induced increase in p38 MAPK phosphorylation, 2) reversal of palmitate effects on PGC-1 and mitochondrial gene expression by p38 MAPK inhibitors, and 3) reversal of palmitate effects by small interfering RNA-mediated decreases in p38alpha MAPK. These data indicate that obesity and saturated fatty acids decrease PGC-1 and mitochondrial gene expression and function via p38 MAPK-dependent transcriptional pathways.

Growth hormone-binding protein is directly and IGFBP-3 is inversely associated with risk of female breast cancer

OBJECTIVE

Several components of the GH and IGF systems have been implicated in the development of malignancies. All components of these hormonal systems have never been jointly evaluated in female breast cancer, and previous studies have not examined the role of IGF-binding proteins (IGFBP-4, IGFBP-6) or GH-binding protein (GHBP).

DESIGN

Hospital-based case-control study.

METHODS

In this sample of primarily postmenopausal women, we obtained serum measures of IGF-I, IGF-II, and binding proteins IGFBP-1, IGFBP-3, IGFBP-4, IGFBP-6, as well as GHBP, insulin, and leptin from 74 breast cancer cases and 76 control subjects.

RESULTS

In crude analyses, we found lower age-standardized mean IGF-I, IGFBP-3, IGFBP-4, IGFBP-6, and higher IGFBP-1 and GHBP in breast cancer cases when compared with controls. Multivariate models mutually adjusted for other GH-IGF system components and classical breast cancer risk factors demonstrated an inverse association between IGFBP-3 and risk of breast cancer (odds ratio (OR) = 0.2, P < 0.01) and a direct association between GHBP and disease risk (OR = 3.3, P < 0.01). No significant associations were detected in multivariate analyses among IGF-I, IGF-II or IGFBP-1, IGFBP-4, IGFBP-6 with risk of breast cancer, indicating that these factors may not have effects independent of and/or comparable with IGFBP-3 and GHBP.

CONCLUSIONS

These results support a protective role of IGFBP-3 and demonstrate for the first time an increased risk of breast cancer with higher GHBP, after accounting for variation in IGFs, IGFBPs, and classical breast cancer risk factors.

Depression and serum adiponectin and adipose omega-3 and omega-6 fatty acids in adolescents

The purpose of the present study was to investigate for a possible relationship between depression and serum adiponectin and adipose tissue omega-3 and omega-6 PUFA. The sample consisted of 90 healthy adolescent volunteers from the island of Crete. There were 54 girls and 36 boys, aged 13 to 18. The mean age was 15.2 years. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the Beck Depression Inventory (BDI) and the Center for Epidemiologic Studies Depression Scale (CES-D). Fatty acids were determined by gas chromatography in adipose tissue. CES-D correlated with dihomo-gamma linolenic acid (DGLA). Multiple linear regression analyses showed that BDI was negatively associated with eicosapentaenoic acid (EPA), while CES-D was positively associated with DGLA in adipose tissue. Serum adiponectin was not significantly associated with depression. The negative relationship between adipose EPA and depression in adolescents, is in line with findings of previous studies involving adult and elderly subjects, demonstrating negative relations between depression and adipose omega-3 PUFA. This is the first literature report of a relationship between depression and an individual omega-3 fatty acid in adolescents. The inverse relationship between adipose EPA and depression indicates that a low long-term dietary intake of EPA is associated with an increased risk for depression in adolescents.

Dietary fibers and glycemic load, obesity, and plasma adiponectin levels in women with type 2 diabetes

OBJECTIVE

The purpose of this study was to examine the associations of dietary fibers and glycemic load with plasma adiponectin in diabetic women and investigate the modification effect of obesity.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional analysis in 902 women with type 2 diabetes from the Nurses' Health Study. Dietary information was obtained using semiquantitative food frequency questionnaires.

RESULTS

After adjustment for age, smoking, alcohol consumption, physical activity, aspirin use, HbA(1c), history of hypertension and hypercholesterolemia, and postmenopausal hormone use, intakes of cereal fiber and fruit fiber (P for trend = 0.002 and 0.036, respectively) were significantly associated with an increasing trend of plasma adiponectin concentrations. Further adjustment for BMI did not appreciably change the associations for cereal fiber but attenuated the associations for fruit fiber. Adiponectin concentrations were 24% higher in the highest compared with the lowest quintile of cereal fiber. Dietary glycemic load and glycemic index were significantly associated with lower plasma adiponectin levels, after adjustment for BMI and other covariates (P for trend = 0.01 and 0.03, respectively). The percent differences in adiponectin concentration between the highest and the lowest quintiles of dietary glycemic load and glycemic index were 17 and 18%, respectively. The associations between dietary factors and plasma adiponectin were consistent across lean (BMI <25 kg/m(2)), overweight (25 <or= BMI <30 kg/m(2)), and obese subjects (BMI >or=30 kg/m(2)).

CONCLUSIONS

Our data indicate that dietary cereal fiber and glycemic load/index are associated with the circulating adiponectin concentration. Such associations were not modified by obesity status.

Leptin Receptor Expression and Signaling in Lymphocytes: Kinetics During Lymphocyte Activation, Role in Lymphocyte Survival, and Response to High Fat Diet in Mice

Leptin has direct effects not only on neuroendocrine function and metabolism, but also on T cell-mediated immunity. We report in this study that leptin receptor (ObR) is expressed on resting normal mouse CD4(+), CD8(+), B cells, and monocyte/macrophages. ObR expression is up-regulated following cell activation, but with different kinetics, in different lymphocyte subsets. Leptin binding to ObR results in increased STAT-3 activation in T cells, with a different activation pattern in resting vs anti-CD3 Ab stimulated T cells. Leptin also promotes lymphocyte survival in vitro by suppressing Fas-mediated apoptosis. B lymphocytes appear to be more susceptible to the antiapoptotic effects of leptin, and they show higher surface expression of ObR, compared with T cells. Moreover, CD4(+) T cells isolated from ObR-deficient mice displayed a reduced proliferative response, compared with normal controls. Furthermore, ObR/STAT-3-mediated signaling in T lymphocytes is decreased in the diet-induced obese mouse model of obesity and leptin resistance. In summary, our findings show that the ObR is expressed on normal mouse lymphocyte subsets, that leptin plays a role in lymphocyte survival, and that leptin alters the ObR/STAT-3-mediated signaling in T cells. Taken together, our data further support the notion that nutritional status acting via leptin-dependent mechanisms may alter the nature and vigor of the immune response.

Leptin and Adiponectin in the HIV Associated Metabolic Syndrome: Physiologic and Therapeutic Implications

Leptin and adiponectin represent two newly discovered adipose tissue derived hormones with important roles in energy homeostasis and insulin resistance. Their interrelations with the manifestations of the HIV associated metabolic syndrome and specific somatomorphic changes i.e. fat redistribution is reviewed. A synopsis of published studies is presented and the potential role of leptin and adiponectin is discussed. We have described an association of the HIV metabolic syndrome with a state of reduced insulin sensitivity due to adiponectin deficiency. The metabolic syndrome is also accompanied by leptin deficiency in lipoatrophic subjects and possibly by a leptin resistance state in lipohypertrophic patients. Adiponectin and / or leptin therapy in a manner similar to other leptin deficiency states may assist in the future management of such patients.

Whole-grain, bran, and cereal fiber intakes and markers of systemic inflammation in diabetic women

OBJECTIVE

To evaluate the dietary predictors for the markers of systemic inflammation and endothelial dysfunction in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We examined whether intakes of whole grains and dietary fiber were associated with inflammatory indicators among 902 diabetic women in the Nurses' Health Study.

RESULTS

After adjustment for age, BMI, lifestyle, and dietary covariates, intakes of whole grains and bran were both associated with significantly decreasing trends of C-reactive protein (CRP) (P for trend = 0.03 and 0.007, respectively) and tumor necrosis factor-alpha receptor 2 (TNF-R2) (P for trend = 0.017 and 0.06). High intake of cereal fiber was also inversely associated with the lower levels of CRP (P for trend = 0.03) and TNF-R2 (P for trend = 0.01). The concentrations of CRP and TNF-R2 were 18 and 8% lower in the highest quintile of cereal fiber as compared with the lowest quintile. Dietary glycemic index was positively associated with CRP (P for trend = 0.04) and TNF-R2 (P for trend = 0.0008) levels. The concentrations of CRP and TNF-R2 were 32 and 11% higher, respectively, in the highest quintile of dietary glycemic index as compared with the lowest quintile.

CONCLUSIONS

Our data indicate that whole grains and a low-glycemic index diet may reduce systemic inflammation among women with type 2 diabetes.

Regulation of mouse hepatic genes in response to diet induced obesity, insulin resistance and fasting induced weight reduction

Background

Obesity is associated with insulin resistance that can often be improved by caloric restriction and weight reduction. Although many physiological changes accompanying insulin resistance and its treatment have been characterized, the genetic mechanisms linking obesity to insulin resistance are largely unknown. We used DNA microarrys and RT-PCR to investigate significant changes in hepatic gene transcription in insulin resistant, diet-induced obese (DIO)-C57/BL/6J mice and DIO-C57/BL/6J mice fasted for 48 hours, whose weights returned to baseline levels during these conditions.

Results

Transcriptional profiling of hepatic mRNA revealed over 1900 genes that were significantly perturbed between control, DIO, and fasting/weight reduced DIO mice. From this set, our bioinformatics analysis identified 41 genes that rigorously discriminate these groups of mice. These genes are associated with molecular pathways involved in signal transduction, and protein metabolism and secretion. Of particular interest are genes that participate in pathways responsible for modulating insulin sensitivity. DIO altered expression of genes in directions that would be anticipated to antagonize insulin sensitivity, while fasting/ weight reduction partially or completely normalized their levels. Among these discriminatory genes, Sh3kbp1 and RGS3, may have special significance. Sh3kbp1, an endogenous inhibitor of PI-3-kinase, was upregulated by high-fat feeding, but normalized to control levels by fasting/weight reduction. Because insulin signaling occurs partially through PI-3-kinase, increased expression of Sh3kbp1 by DIO mice may contribute to hepatic insulin resistance via inhibition of PI-3-kinase. RGS3, a suppressor of G-protein coupled receptor generation of cAMP, was repressed by high-fat feeding, but partially normalized by fasting/weight reduction. Decreased expression of RGS3 may augment levels of cAMP and thereby contribute to increased, cAMP-induced, hepatic glucose output via phosphoenolpyruvate carboxykinase (PCK1), whose mRNA levels were also elevated.

Conclusion

These findings demonstrate that hepatocytes respond to DIO and weight reduction by controlling gene transcription in a variety of important molecular pathways. Future studies that characterize the physiological significance of the identified genes in modulating energy homeostasis could provide a better understanding of the mechanisms linking DIO with insulin resistance.

A prospective study of soluble tumor necrosis factor-alpha receptor II (sTNF-RII) and risk of coronary heart disease among women with type 2 diabetes

OBJECTIVE

Tumor necrosis factor-alpha (TNF-alpha), a cytokine secreted by adipose tissue and other cells, might play a role in insulin resistance.

RESEARCH DESIGN AND METHODS

Of 32,826 women from the Nurses' Health Study who provided blood at baseline, we followed 929 women with type 2 diabetes. During 10 years of follow-up, we documented 124 incident cases of coronary heart disease (CHD).

RESULTS

After adjustment for age, smoking, BMI, and other cardiovascular risk factors, the relative risks (RRs) comparing extreme quartiles of soluble TNF-alpha receptor II (sTNF-RII) were 2.48 (95% CI 1.08-5.69; P = 0.034) for myocardial infarction (MI) and 2.02 (1.17-3.48; P = 0.003) for total CHD. The probability of developing CHD over 10 years was higher among diabetic subjects with substantially higher levels of both sTNF-RII (>75th percentile) and HbA(1c) (>7%), compared with diabetic subjects with lower levels (25% vs. 7%, P < 0.0001). Diabetic subjects with only higher sTNF-RII or HbA(1c) had similar (16-17%) risk. In a multivariate model, diabetic subjects with higher levels of both sTNF-RII and HbA(1c) had an RR of 3.66 (1.85-7.22) for MI and 3.03 (1.82-5.05) for total CHD, compared with those with lower levels of both biomarkers.

CONCLUSIONS

Increased levels of sTNF-RII were strongly associated with risk of CHD among diabetic women, independent of hyperglycemia.

Serum adiponectin concentrations in relation to maternal and perinatal characteristics in newborns

OBJECTIVE

To assess serum adiponectin levels of neonates in relation to ponderal index and birth length with and without adjustment for potential confounding factors including maternal factors and perinatal characteristics.

DESIGN

A cross-sectional study.

METHODS

Three hundred and three newborns (Caucasian, singleton, full term, with a birth weight of > or =2500 g, and apparently healthy) were included in the study. Blood samples were collected from the newborns no later than the fifth day of life for measurements of adiponectin and major IGF system components (IGF-I, IGF-II, IGF binding protein-3 (IGFBP-3)). The data were analyzed using simple and multiple regression analyses.

RESULTS

Adiponectin is substantially higher in neonates than in adults, with no evidence of the gender dimorphism observed among adults. We found an inverse association between neonatal adiponectin levels and newborn ponderal index and a positive association with newborn length by univariate analysis. We also found a statistically significant inverse association of adiponectin with jaundice/bilirubin, and a marginally significant positive association of this hormone with IGFBP-3 but no significant association with any maternal factors. In multivariate analysis, the inverse association between serum adiponectin and ponderal index does not remain significant after adjustment for potential confounding factors. In contrast, neonatal adiponectin levels correlate inversely significantly and independently with liver maturity and IGF-II and tend to remain positively associated with IGFBP-3 and increased birth length.

CONCLUSIONS

An inverse association of adiponectin with ponderal index by univariate analysis is not independent from confounding factors. In contrast, the positive association between serum adiponectin and birth length may reflect either a direct effect of adiponectin or an adiponectin-mediated increase in the sensitivity of tissues to insulin and components of the IGF system, and needs to be explored further.

Adiponectin and breast cancer risk

Adiponectin, an adipocyte-secreted hormone, is closely and inversely associated with insulin resistance and was recently found to be inversely and independently associated with endometrial cancer. Because insulin resistance in the setting of obesity has also been associated with the development of breast cancer, we have hypothesized that decreased adiponectin levels might underlie the association between breast cancer and obesity/insulin resistance. We evaluated the association of adiponectin with the occurrence of breast cancer in a case-control study comprising 174 women with newly diagnosed, histologically confirmed breast cancer and 167 controls. We found an inverse, fairly strong, and statistically significant association of serum adiponectin with breast cancer (odds ratio, 0.84; 95% confidence interval, 0.71-0.99). Importantly, despite a fairly robust inverse association of adiponectin with breast cancer risk among postmenopausal women (odds ratio, 0.82; 95% confidence interval, 0.67-1.00), no such significant association between adiponectin and breast cancer was found among premenopausal women. The observed associations were independent of possible effects of major components of the IGF system, leptin, body mass index, sociodemographic variables, and known risk factors for breast cancer. Future studies are needed to prove causality and provide further insights into both the mechanisms underlying the actions of this hormone and its potential role in breast cancer.

Increased leptin levels in preeclampsia: associations with BMI, estrogen and SHBG levels

Leptin is secreted mainly by the white adipose tissue but is also synthesized in several non-adipose tissue organs including the placenta. Serum leptin levels are increased in normal pregnancies and are higher in preeclamptic than normal pregnant women. There is, however, a lack of empirical evidence of an independent association of serum leptin levels and preeclamsia. We have studied cross-sectionally 18 3rd trimester preeclamptic women, 28 3rd trimester and 30 2nd trimester control women to confirm the reported increase of serum leptin in preeclampsia and to assess whether elevated leptin levels in preeclampsia increase the variance explained by body mass index (BMI), androgens, estrogens and/or sex hormone binding globulin (SHBG). Anthropometric, demographic and hormonal data were analyzed using linear and logistic regression models.

RESULTS

Leptin is significantly increased in preeclampsia by univariate analysis, but use of multivariate analysis indicates that the elevated leptin levels are not associated with preeclampsia independently from BMI, estrogens and SHBG.

CONCLUSION

This study confirms that leptin levels are higher in women with preeclampsia than in controls and demonstrates that serum leptin levels do not add to the prediction of preeclampsia after accounting for BMI, estrogen and SHBG levels of preeclamptic women.