Leptin, not adiponectin, predicts hypertension in the Copenhagen City Heart Study

Exergaming Improves Cardiac Risk Factors in Prostate Cancer Patients: A Single-Blinded Randomized Controlled Trial

Purpose: Androgen deprivation therapy (ADT) may induce unfavorable changes in metabolic outcomes, insulin sensitivity, insulin-like growth factors (IGFs), and in serum levels of adipocyte-derived hormones. In this preplanned randomized ancillary study, we aimed to investigate the ability of exercise to counteract alterations in triglyceride, cholesterol, waist circumference, and insulin caused by ADT in men with locally advanced and metastatic prostate cancer (PCa). Materials and Methods: Forty-six PCa patients undergoing treatment were randomized to 12 weeks of 180 minutes of weekly unsupervised home-based exergaming or usual care. Blood glucose, lipids, cholesterol, adiponectin, leptin, insulin sensitivity, and the insulin growth factor axis were measured at baseline, and after 12 and 24 weeks. Biomarkers were analyzed using a linear mixed-effect model of the difference between the groups from baseline to week 24. In addition, blood pressure, body mass index, body weight, and waist circumference were measured at baseline and after 12 weeks/end of intervention and analyzed using adjusted linear regression analysis. Results: After 24 weeks, a significant difference was seen between the intervention and usual care groups in plasma triglyceride (diff: 0.5 mmol/L, P = 0.02) and high-density lipoprotein (HDL; diff: 0.2 mmol/L, P = 0.01) favoring the intervention group, whereas IGF-binding protein-3 (diff: 148 μg/L, P = 0.01) favored the usual care group. The remaining outcomes were unaffected. Conclusion: Improvement in HDL cholesterol could be used as a primary biomarker in future randomized controlled trials investigating the cardiovascular protecting properties of exergaming.

The associations of adipokines with hypertension in youth with cardiometabolic risk and the mediation role of insulin resistance: The BCAMS study

The mechanisms link obesity and hypertension are not well understood. One possibility is the alterations in adipose-derived adipokines that modulate insulin resistance (IR) and cardiovascular homeostasis. We aimed to assess the associations between hypertension and four adipokine levels in Chinese youth, and to examine to what extent the associations are mediated by IR. We utilized cross-sectional data from the Beijing Children and Adolescents Metabolic Syndrome (BCAMS) Study Cohort (n = 559, mean age = 20.2 years). Plasma leptin, adiponectin, retinol binding protein 4 (RBP4) and fibroblast growth factor 21 (FGF21) levels were assayed. The relationships between adipokines and hypertension and the possible mediation effect of IR were evaluated. Youth with hypertension have lower adiponectin and higher leptin, FGF21 (all P < 0.001) and RBP4 levels (p = 0.06) compared to their counterparts. Moreover, the co-existence of these two or more adipokine abnormalities in youth leads to a 9-fold increased risk for hypertension (OR: 9.19; 95% CI, 4.01-21.08) compared with these without abnormalities. However, in the fully adjusted and BMI-adjusted analyses, only FGF21 was a significant predictor of hypertension (OR: 2.12; 95% CI, 1.34-3.36). Mediation analysis revealed that the associations between leptin, adiponectin, RBP4 and hypertension are totally mediated by IR (proportion: 63.9%, 65.4%, and 31.6%, respectively), while BMI and IR partly mediated the association between FGF21 and hypertension (proportion: 30.6%, 21.2%). Our findings suggest that dysregulation of adipokines might result in hypertension in youth. Leptin, adiponectin and RBP4 may exert their functions in hypertension through adiposity-related IR, whereas FGF21 might be used as an independent marker of hypertension in youth.

Normal bone mineral density and bone microarchitecture in adult males with high and low risk of exercise addiction

Exercise addiction describes a pattern of excessive and obsessive exercise and is associated with hypoleptinemia and low testosterone that may have adverse skeletal effects. We used a validated questionnaire to identify males with high and low risk of exercise addiction. In a cross-sectional design, males (aged 21–49 years) with high (n = 20, exercise addictive) and low risk (n = 20, exercise controls) of exercise addiction had examinations of bone mass, bone microarchitecture, and estimated bone strength performed using dual-energy x-ray absorptiometry of the hip and spine and high-resolution peripheral quantitative computed tomography of the distal radius and tibia. Findings were compared between the groups and to a population-based sample of healthy men aged 20–80 years (n = 236). We found similar hip and spine bone mineral density in exercise addictive and controls. Cortical and trabecular bone microarchitecture and estimated bone strength in radius and tibia did not differ significantly between the groups. Multiple regression analyses adjusting for age, body weight, free testosterone, and hours of weekly training did not alter findings. Also, bone indices from both groups were within 95% prediction bands derived from the population-based sample for the vast majority of indices. Neither group had no associations between circulating leptin or free testosterone and bone outcomes. In conclusion, in a study on younger males, we found no associations between high risk of exercise addiction and various indices of bone mass and bone quality indicative of altered skeletal health.

Leptin Receptor Blockade Attenuates Hypertension, but Does Not Affect Ventilatory Response to Hypoxia in a Model of Polygenic Obesity

Background

Obesity can cause hypertension and exacerbates sleep-disordered breathing (SDB). Leptin is an adipocyte-produced hormone, which increases metabolic rate, suppresses appetite, modulates control of breathing, and increases blood pressure. Obese individuals with high circulating levels of leptin are resistant to metabolic and respiratory effects of leptin, but they appear to be sensitive to hypertensive effects of this hormone. Obesity-induced hypertension has been associated with hyperleptinemia. New Zealand obese (NZO) mice, a model of polygenic obesity, have high levels of circulating leptin and hypertension, and are prone to develop SDB, similarly to human obesity. We hypothesize that systemic leptin receptor blocker Allo-aca will treat hypertension in NZO mice without any effect on body weight, food intake, or breathing.

Methods

Male NZO mice, 12–13 weeks of age, were treated with Allo-aca (n = 6) or a control peptide Gly11 (n = 12) for 8 consecutive days. Doses of 0.2 mg/kg were administered subcutaneously 2×/day, at 10 AM and 6 PM. Blood pressure was measured by telemetry for 48 h before and during peptide infusion. Ventilation was assessed by whole-body barometric plethysmography, control of breathing was examined by assessing the hypoxic ventilatory response (HVR), and polysomnography was performed during light-phase at baseline and during treatment. Heart rate variability analyses were performed to estimate the cardiac autonomic balance.

Results

Systemic leptin receptor blockade with Allo-aca did not affect body weight, body temperature, and food intake in NZO mice. Plasma levels of leptin did not change after the treatment with either Allo-aca or the control peptide Gy11. NZO mice were hypertensive at baseline and leptin receptor blocker Allo-aca significantly reduced the mean arterial pressure from 134.9 ± 3.1 to 124.9 ± 5.7 mmHg during the light phase (P < 0.05), whereas the control peptide had no effect. Leptin receptor blockade did not change the heart rate or cardiac autonomic balance. Allo-aca did not affect minute ventilation under normoxic or hypoxic conditions and HVR. Ventilation, apnea index, and oxygen desaturation during NREM and REM sleep did not change with leptin receptor blockade.

Conclusion

Systemic leptin receptor blockade attenuates hypertension in NZO mice, but does not exacerbate obesity and SDB. Thus, leptin receptor blockade represents a potential pharmacotherapy for obesity-associated hypertension.

Pharmacological and Genetic Blockade of Trpm7 in the Carotid Body Treats Obesity-Induced Hypertension

[Figure: see text].

Plasma Adiponectin and Blood Pressure Progression in African Americans: The Jackson Heart Study

BACKGROUND

Little is known on the association of plasma adiponectin with blood pressure (BP) changes in African Americans (AAs). We evaluated the associations between plasma adiponectin and BP progression among AAs.

METHODS

We analyzed data from 1,184 participants without hypertension at baseline (2000-2004) with ≥1 follow-up visits in the Jackson Heart Study. We used robust Poisson regression to generate risk ratios (RRs) for BP progression (an increase by ≥1 BP stage) and incident hypertension.

RESULTS

Over a median of 7 years, 71% progressed to higher BP stage and 65% developed hypertension. We found evidence of interaction by sex (P-interaction = 0.088). Compared with those in the lowest quartile (Q1), male participants in the highest adiponectin quartile (Q4) had reduced risks of BP progression (RR 0.76 [95% confidence interval, CI, 0.60-0.96]) and incident hypertension (RR 0.74 [95% CI 0.56-0.97]). After accounting for body mass index, this relation persisted among obese men (RR for the highest [vs. lowest] adiponectin quartile: 0.59 [95% CI 0.36-0.97] for incident hypertension, and 0.69 [95% CI 0.45-1.06] for BP progression). Among women, adiponectin was not associated with BP outcomes (RR [95% CI] for Q4 vs. Q1: 1.03 [0.86-1.23] and 1.01 [0.83-1.23] for BP progression and incident hypertension, respectively). Our findings were consistent across both the American College of Cardiology (ACC)/American Heart Association (AHA) and Seventh Joint National Committee (JNC-7) BP categories.

CONCLUSIONS

In a large, community-based sample of AAs, higher adiponectin concentrations were associated with lower risks of BP progression and incident hypertension in men, but no significant association was observed in women.

Plasma Leptin and Blood Pressure Progression in Blacks: The Jackson Heart Study

[Figure: see text].

[Characteristics of arterial hypertension clinical course in patients with obesity and anxiety-depressive disorders]

This article covers an important subject clinical course of arterial hypertension in patients with metabolic abnormalities with obesity and anxiety-depressive disorders. Relevance of this topic is defined with high incidence of each aforementioned conditions and their influence on quality of life and social functioning of patients. Review of literature covers subjects of comorbidity and multimorbidity. Relevant data are presented which are focusing on complex management of arterial hypertension co-existing with obesity and anxiety-depressive disorders.

Advances in Cardiovascular Biomarker Discovery

Cardiovascular diseases are the leading causes of mortality worldwide. Among them, hypertension and its pathological complications pose a major risk for the development of other cardiovascular diseases, including heart failure and stroke. Identifying novel and early stage biomarkers of hypertension and other cardiovascular diseases is of paramount importance in predicting and preventing the major morbidity and mortality associated with these diseases. Biomarkers of such diseases or predisposition to their development are identified by changes in a specific indicator’s expression between healthy individuals and patients. These include changes in protein and microRNA (miRNA) levels. Protein profiling using mass spectrometry and miRNA screening utilizing microarray and sequencing have facilitated the discovery of proteins and miRNA as biomarker candidates. In this review, we summarized some of the different, promising early stage protein and miRNA biomarker candidates as well as the currently used biomarkers for hypertension and other cardiovascular diseases. Although a number of promising markers have been identified, it is unlikely that a single biomarker will unambiguously aid in the classification of these diseases. A multi-marker panel-strategy appears useful and promising for classifying and refining risk stratification among patients with cardiovascular disease.

The association between serum inflammatory biomarkers and incident hypertension among postmenopausal women in the Buffalo OsteoPerio Study

Several serum inflammatory biomarkers have been associated with blood pressure and hypertension prevalence in cross-sectional studies. Few of these associations have been evaluated prospectively. We examined associations for 10 serum inflammatory biomarkers with incident hypertension among 471 postmenopausal women (mean age = 65) in the Buffalo OsteoPerio Study. Concentrations of C-reactive protein, interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, adiponectin, and leptin were measured using multiplexed sandwich immunoassays on fasting serum samples collected at baseline (1997–2001). Incident hypertension (195 cases) was defined as physician-diagnosed hypertension and treatment with medication identified on annual mailed health surveys during follow-up (mean 10 years). Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) between log-transformed biomarkers (per 1-SD) and hypertension. When adjusted for age, leptin was significantly associated with hypertension risk (HR=1.55, 95% CI: 1.04, 2.29), however, the association was attenuated and not significant after adjustment for demographic and lifestyle factors, including BMI. Significant (P<0.10) interactions were observed for smoking (never, ever) with CRP (HR: Never, 1.31; Ever, 0.91; P=0.06) and MCP-1 (HR: Never, 0.59; Ever, 5.11; P=0.004); for BMI (<25, ≥25) with MCP-1(HR: <25, 3.45; ≥25, 0.95; P=0.07); for systolic BP with IL-10 (HR: <120, 0.85; 120–139, 1.11; P=0.07); and for diastolic BP with MCP-1 (HR: <80, 1.29; 80–89, 0.84; P=0.03) and with adiponectin (HR: <80, 0.86; 80–89, 1.50; P=0.03). This study adds needed understanding on prospective associations between several serum inflammatory biomarkers and hypertension risk in older postmenopausal women, among whom hypertension burden is substantial.

Changes in insulin sensitivity and insulin secretion during pregnancy and post partum in women with gestational diabetes

INTRODUCTION

The metabolic abnormalities underlying gestational diabetes mellitus (GDM) include increased insulin resistance and beta cell defects, but it is essential to clarify how insulin resistance and insulin secretion develop post partum in order to decide when and how to screen for type 2 diabetes. The purpose of the present study was to characterize and compare changes in insulin sensitivity, insulin secretion and hormonal status around parturition and 6 months post partum in women with gestational diabetes.

RESEARCH DESIGN AND METHODS

A longitudinal experimental study was performed at Aarhus University Hospital, Denmark. Eight women with GDM were examined at three identical visits: in late pregnancy (LP) between gestational age 34+0 and 36+6, early post partum (EPP) between 12 and 34 days post partum, and late post partum (LPP) 6 months post partum. An intravenous glucose tolerance test was performed, followed by a hyperinsulinemic euglycemic clamp. Blood samples were collected to assess metabolic, hormonal and inflammatory markers at each visit.

RESULTS

First and second phase insulin secretion and C-peptide concentrations were higher in late pregnancy than post partum (p<0.001). Insulin sensitivity index (ISI) was different at all three visits: ISI_LP=0.03±0.004, ISI_EPP=0.09±0.008 and ISI_LPP=0.07±0.008) (p<0.001). Also, significant changes in lipids, leptin, glucagon, growth hormone and insulin-like growth factor-1 were seen when comparing the visits.

CONCLUSIONS

Insulin sensitivity improves immediately after delivery in women with GDM but seems to deteriorate within the first 6 months post partum. Our findings underline the importance of having an increased awareness of the profound risk of developing type 2 diabetes after GDM.

TRIAL REGISTRATION NUMBER

NCT02770079.

Obesity, Hypertension, and Bariatric Surgery

PURPOSE OF REVIEW

Obesity increases the risk of hypertension. However, blood pressure decreases before any significant loss of body weight after bariatric surgery. We review the mechanisms of the temporal dissociation between blood pressure and body weight after bariatric surgery.

RECENT FINDINGS

Restrictive and bypass bariatric surgery lower blood pressure and plasma leptin levels within days of the procedure in both hypertensive and normotensive morbidly obese patients. Rapidly decreasing plasma leptin levels and minimal loss of body weight point to reduced sympathetic nervous system activity as the underlying mechanism of rapid blood pressure decline after bariatric surgery. After the early rapid decline, blood pressure does not decrease further in patients who, while still obese, experience a steady loss of body weight for the subsequent 12 months. The divergent effects of bariatric surgery on blood pressure and body weight query the role of excess body weight in the pathobiology of the obesity phenotype of hypertension. The decrease in blood pressure after bariatric surgery is moderate and independent of body weight. The lack of temporal relationship between blood pressure reduction and loss of body weight for 12 months after sleeve gastrectomy questions the nature of the mechanisms underlying obesity-associated hypertension.

The Role of Adipokines in the Development of Arterial Stiffness and Hypertension

The study aimed to assess the role and the relationship of adipokines as well as parameters of arterial stiffness in newly diagnosed hypertension. Forty-nine newly diagnosed hypertensive cases (median age 47 ± 6 years) and 48 normotensive patients (median age 47 ± 6 years) were enrolled to this study. Patients underwent echocardiography, noninvasive assessment of hemodynamic parameters using SphygmoCor tonometer (Atcor Med). The levels of the adipokines-leptin, adiponectin, and resistin-were investigated. The augmentation pressure, augmentation index, and pulse wave velocity (PWV) were higher in patients with hypertension compared with controls (Ps < .05). Patients with hypertension had higher E/E' ratio, higher diameter of left atrium, and lower tricuspid annular plane systolic excursion compared with the control group (Ps < .05). Patients with hypertension had significant higher levels of leptin (ng/mL) and lower levels of adiponectin (μg/mL) compared with normotensive patients. The multivariate analysis showed that PWV (odds ratio [OR] 1.95, 95% CI, 1.2-2.9; P = .002) and leptin level (OR 1.01, 95% CI, 1.004-1.031; P = .01) were significantly associated with hypertension. Arterial stiffness as determined by PWV and leptin are associated with newly diagnosed hypertension. Elevated serum leptin level may influence the potential mechanism leading to sympathetic activation.

Altered adipocytokine profile predicts early stage of left ventricular remodeling in hypertensive patients with type 2 diabetes mellitus

BACKGROUND AND AIM

Adipocytokine dysfunction is considered as causative factor of target organ damage in metabolic disease. The aim of the study was to investigate whether altered adipocytokine profile predicts left ventricular (LV) remodeling in hypertensive patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 186 patients (125 hypertensive and 61 non-hypertensive individuals) with established T2DM and 20 healthy volunteers were enrolled in the study. LV remodeling was determined at baseline. Concentrations of adipocytokines were measured with ELISA at baseline.

RESULTS

The most important predictors of LV hypertrophy in T2DM patients were serum levels of omentin-1 (B-coefficient = -0.64, p = 0.001), Zinc-α2-glycoprotein [ZA2G] (B-coefficient = -0.57, p = 0.002), visfatin (B-coefficient = 0.26, p = 0.034), hs-CRP (B-coefficient = 0.38, p = 0.002), HOMA-IR (B-coefficient = 0.34, p = 0.001), age (B-coefficient = 0.31, p = 0.022), glypican-4 (B-coefficient = -0.23, p = 0.042), and male sex (B-coefficient = 0.11, p = 0.048). After entering combined depending variable (LV hypertrophy and LV diastolic dysfunction) to the model the significant predictors remained serum levels of omentin-1 (B-coefficient = -0.82, p = 0.001), ZA2G (B-coefficient = -0.54, p = 0.001) and HOMA-IR (B-coefficient = 0.44, p = 0.001). Regression analyses showed that the most influential determinants of depending variable (LV hypertrophy + LV diastolic dysfunction) in T2DM patients were omentin-1 (B-coefficient = -1.6, p = 0.001) and ZA2G (B-coefficient = -0.78, p = 0.044).

CONCLUSION

We found that serum levels of omentin-1 and ZA2G were the most important predictors for LV hypertrophy + LV diastolic dysfunction in T2DM patients. Large clinical trials are required to confirm this assumption and get clear explanation of issues unveiled.

Modification effect of sex and obesity on the correlation of LEP polymorphisms with leptin levels in Taiwanese obese women

Background

Obesity has become the main health issue in developed countries as it impacts life expectancy and increases mortality of cerebrovascular or cardiovascular diseases. The leptin is one of the adipokines which presents in the serum in proportion to the amount of adipose tissue and is translated from LEP gene. It involves in energy homeostasis, lipid and glucose metabolisms, modulation of immune systems, and thermogenesis. Many previous studies have revealed controversial results between LEP polymorphisms and leptin levels in different ages and ethnicities. Herein, we investigated the impacts of LEP polymorphism against leptin levels in Taiwanese subjects.

Methods

In 599 Taiwanese subjects, excluding clinically overt systemic disease, age below 18 years old, and C‐reactive protein (CRP) level of above 10 mg/L, few of LEP polymorphisms were genotyped with TaqMan SNP genotyping assays, were further analyzed for association with leptin level in univariate and multivariate linear regression analyses with Bonferroni correction for multiple tests in stratified groups. The univariate and stepwise multivariate linear regression analyses were performed to determine the coefficient of determinant of LEP polymorphisms over leptin level.

Results

Significant associations were found between LEP polymorphisms and leptin levels in obese women. Circulating leptin level was positively correlated with inflammatory, insulin resistance markers, and visceral obesity markers in all subjects. Furthermore, stratified and interaction analyses revealed that LEP polymorphisms, rs7799039 and rs2167270, were significantly associated with leptin levels in obese women—8%–10% of which could be explained by LEP polymorphisms.

Conclusion

The LEP polymorphisms are independently associated with leptin levels in Taiwanese obese women. Further, the genetic determinants for leptin levels may be different between obese and nonobese, and in different sex individuals. The obesity status and female sex may exert modification effect on transcription of LEP, particularly in obese women.

Total adiponectin is associated with incident cardiovascular and renal events in treated hypertensive patients: subanalysis of the ATTEMPT-CVD randomized trial

The predictive value of serum adiponectin for hypertensive cardiovascular outcomes is unknown. This study was performed to investigate the association of adiponectin with incident cardiovascular and renal events (CV events) in hypertensive patients. We performed post-hoc analysis on 1,228 hypertensive patients enrolled in the ATTEMPT-CVD study, a prospective randomized study comparing the effects of two antihypertensive therapies. The participants were divided into quartiles of baseline serum total adiponectin or high molecular weight (HMW) adiponectin. Multivariable Cox proportional hazards analysis was performed to determine the prognostic factors associated with CV events. Kaplan-Meier analysis for CV events by quartiles of baseline total adiponectin showed that patients in the highest total adiponectin quartile (Q4) had more CV events (P = 0.0135). On the other hand, no significant difference was noted regarding the incidence of CV events among patients stratified by HMW adiponectin quartile (P = 0.2551). Even after adjustment for potential confounders, the highest total adiponectin quartile (Q4) remained independently associated with incident CV events in hypertensive patients (HR = 1.949: 95%CI 1.051-3.612; P = 0.0341). These results showed that total adiponectin, but not HMW adiponectin, was independently associated with the incidence of CV events in treated hypertensive patients, thereby highlighting total adiponectin as a valuable predictor for hypertensive cardiovascular outcomes.

Leptin Induces Hypertension Acting on Transient Receptor Potential Melastatin 7 Channel in the Carotid Body

RATIONALE

Obesity leads to resistant hypertension and mechanisms are poorly understood, but high plasma levels of leptin have been implicated. Leptin increases blood pressure acting both centrally in the dorsomedial hypothalamus and peripherally. Sites of the peripheral hypertensive effect of leptin have not been identified. We previously reported that leptin enhanced activity of the carotid sinus nerve, which transmits chemosensory input from the carotid bodies (CBs) to the medullary centers, and this effect was abolished by nonselective blockers of Trp (transient receptor potential) channels. We searched our mouse CB transcriptome database and found that the Trpm7 (transient receptor potential melastatin 7) channel was the most abundant Trp channel.

OBJECTIVE

To examine if leptin induces hypertension acting on the CB Trpm7.

METHODS AND RESULTS

C57BL/6J (n=79), leptin receptor (LepRb) deficient db/db mice (n=22), and LepRb-EGFP (n=4) mice were used. CB Trpm7 and LepRb gene expression was determined and immunohistochemistry was performed; CB glomus cells were isolated and Trpm7-like current was recorded. Blood pressure was recorded continuously in (1) leptin-treated C57BL/6J mice with intact and denervated CB; (2) leptin-treated C57BL/6J mice, which also received a nonselective Trpm7 blocker FTY720 administered systemically or topically to the CB area; (3) leptin-treated C57BL/6J mice transfected with Trpm7 small hairpin RNA to the CB, and (4) Leprb deficient obese db/db mice before and after Leprb expression in CB. Leptin receptor and Trpm7 colocalized in the CB glomus cells. Leptin induced a nonselective cation current in these cells, which was inhibited by Trpm7 blockers. Leptin induced hypertension in C57BL/6J mice, which was abolished by CB denervation, Trpm 7 blockers, and Trpm7 small hairpin RNA applied to CBs. Leprb overexpression in CB of Leprb-deficient db/db mice demethylated the Trpm7 promoter, increased Trpm7 gene expression, and induced hypertension.

CONCLUSIONS

We conclude that leptin induces hypertension acting on Trmp7 in CB, which opens horizons for new therapy.

Sex and Body Mass Index Modify the Association Between Leptin and Sodium Excretion: A Cross-sectional Study in an African Population

BACKGROUND

Renal sodium handling could be a potential mediator linking adipokines to hypertension. The aim of the study was to assess the relationship of leptin with urinary sodium excretion and proximal sodium reabsorption in humans.

METHODS

This cross-sectional study was conducted on participants of hypertensive families from the Seychelles Island. A split urine (daytime and nighttime) collection and plasma leptin were measured. Endogenous lithium clearance was used to assess proximal sodium reabsorption. Mixed multiple linear regression tests adjusted for confounding factors were used.

RESULTS

Three hundred and sixty-five participants (57% women) were included in this analysis. Leptin and adiponectin were higher in women (P < 0.001). Leptin was associated positively with daytime (coefficient [c]: 0.16, standard deviation (SD): 0.03, P < 0.001), nighttime urinary sodium excretion (c: 0.17, SD: 0.04), P < 0.01), daytime lithium clearance (c: 0.40, SD: 0.08, P < 0.001), and nighttime lithium clearance (c: 0.39, SD: 0.10, P < 0.001) after adjusting for sex. The association was lost or mitigated only when BMI was introduced in the model. When BMI was categorized in normal vs. overweight participant, leptin was associated with daytime and nighttime sodium excretion rates (c: 0.14, SD: 0.05, P = 0.011 and c: 0.22, SD: 0.07, P = 0.002, respectively) only in overweight participants.

CONCLUSION

Leptin is associated positively with daytime and nighttime sodium excretion and lithium clearance suggesting a natriuretic rather than a sodium retaining effect of leptin. Sex and body mass index (BMI) are major confounders in this association. These results highlight the importance of sex and obesity in our understanding of the relationships between leptin, blood pressure, and renal sodium handling.

Leptin Is Not Essential for Obesity-Associated Hypertension

BACKGROUND AND OBJECTIVE

Hyperleptinemia is supposed to play a causal role in the development of obesity-associated hypertension, possibly via increased sympathetic tone. Hence patients with congenital leptin deficiency should be hypotensive and their low blood pressure should increase under leptin substitution.

SUBJECTS AND METHODS

To test this assumption, we examined ambulatory blood pressure, resting heart rate, Schellong test results, cold pressor test results, heart rate variability, catecholamine metabolites, and aldosterone levels in 6 patients with congenital leptin deficiency before as well as 2-7 days and 7-14 months after the start of leptin substitution. Ambulatory blood pressure was also examined in 3 patients with biallelic disease-causing variants in the leptin receptor gene.

RESULTS

Contrary to our expectations, even before leptin substitution, 1 patient with biallelic leptin receptor gene variants and 4 patients with leptin deficiency had been suffering from hypertension. Short-term substitution with leptin increased blood pressure further in 3 out of 4 patients (from 127.0 ± 11.7 to 133.8 ± 10.6 mm Hg), concomitant with an increase in resting heart rate as well as in heart rate during the Schellong test in all patients (from 87.6 ± 7.7 to 99.9 ± 11.0 bpm, p = 0.031, and from 102.9 ± 13.5 to 115.6 ± 11.3 bpm, p = 0.031, respectively). Furthermore, the systolic blood pressure response during the cold pressor test increased in 4 out of 6 patients. Unexpectedly, catecholamine metabolites and aldosterone levels did not increase. After long-term leptin substitution and weight loss, the resting heart rate decreased in 4 out of 6 patients compared to baseline, and in all patients below the heart rate seen immediately after the start of therapy (from 99.9 ± 11.0 to 81.7 ± 5.4 bpm; p = 0.031).

CONCLUSIONS

These results show that obesity-associated hypertension does not depend on the presence of leptin. However, short-term leptin substitution can increase the blood pressure and heart rate in obese humans with leptin deficiency, indicating that leptin plays at least an additive role in obesity-associated hypertension. The mechanisms behind this are not clear but might include an increase in regional sympathetic tone.

Plasma leptin level is positively associated with blood pressure measures independent of gender and BMI

Background: Since the introduction of leptin, many studies suggest an important role for this hormone in obesity-related hypertension. However, in non-obese patients, there are controversial results regarding the possible role of leptin in essential hypertension especially in both sexes and different groups of body mass index (BMI). We aimed to evaluate the association of leptin and hypertension in both female and male gender.Materials and Methods: This cross-sectional study was conducted, recruiting 80 essential hypertensive patients and 80 healthy normotensive volunteers using convenience sampling method. Subjects without history of diabetes mellitus, hyperlipidemia, smoking, thyroid disease and insulin or corticosteroid use were included in two groups of normotensive and hypertensive subjects who were matched for age, sex and BMI. Systolic and diastolic blood pressure (SBP and DBP), weight and height were measured for all subjects and a blood sample was obtained for measurement of leptin, fasting blood sugar and lipid profiles.Results: Leptin was significantly higher in hypertensive patients as compared to normotensive subjects in all study population and both male and female subgroups (p < 0.001). Statistically significant correlation was also found between leptin and both SBP and DBP in above-mentioned subgroups. In comparison of controlled and uncontrolled hypertensive patients, leptin was significantly higher in uncontrolled hypertensive patients (p < 0.001).Conclusion: Comparing two groups of hypertensive and normotensive subjects, leptin is found to be positively correlated with hypertension in both genders. Leptin level also tends to be higher in uncontrolled hypertensive patients which may indicate a possible role for leptin in mechanism of uncontrolled hypertension.

Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis

BACKGROUND

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring.

RESULTS

The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs).

CONCLUSIONS

We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

Leptin and Leptin Resistance in the Pathogenesis of Obstructive Sleep Apnea: A Possible Link to Oxidative Stress and Cardiovascular Complications

Obesity-related sleep breathing disorders such as obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS) cause intermittent hypoxia (IH) during sleep, a powerful trigger of oxidative stress. Obesity also leads to dramatic increases in circulating levels of leptin, a hormone produced in adipose tissue. Leptin acts in the hypothalamus to suppress food intake and increase metabolic rate. However, obese individuals are resistant to metabolic effects of leptin. Leptin also activates the sympathetic nervous system without any evidence of resistance, possibly because these effects occur peripherally without a need to penetrate the blood-brain barrier. IH is a potent stimulator of leptin expression and release from adipose tissue. Hyperleptinemia and leptin resistance may upregulate generation of reactive oxygen species, increasing oxidative stress and promoting inflammation. The current review summarizes recent data on a possible link between leptin and oxidative stress in the pathogenesis of sleep breathing disorders.

The Role of the Autonomic Nervous System in the Pathophysiology of Obesity

Obesity is reaching epidemic proportions globally and represents a major cause of comorbidities, mostly related to cardiovascular disease. The autonomic nervous system (ANS) dysfunction has a two-way relationship with obesity. Indeed, alterations of the ANS might be involved in the pathogenesis of obesity, acting on different pathways. On the other hand, the excess weight induces ANS dysfunction, which may be involved in the haemodynamic and metabolic alterations that increase the cardiovascular risk of obese individuals, i.e., hypertension, insulin resistance and dyslipidemia. This article will review current evidence about the role of the ANS in short-term and long-term regulation of energy homeostasis. Furthermore, an increased sympathetic activity has been demonstrated in obese patients, particularly in the muscle vasculature and in the kidneys, possibily contributing to increased cardiovascular risk. Selective leptin resistance, obstructive sleep apnea syndrome, hyperinsulinemia and low ghrelin levels are possible mechanisms underlying sympathetic activation in obesity. Weight loss is able to reverse metabolic and autonomic alterations associated with obesity. Given the crucial role of autonomic dysfunction in the pathophysiology of obesity and its cardiovascular complications, vagal nerve modulation and sympathetic inhibition may serve as therapeutic targets in this condition.

Abnormal levels of adipokines in adolescent offspring of women with type 1 diabetes - Results from the EPICOM study

AIMS/HYPOTHESIS

To investigate long-term consequences of diabetes during pregnancy, we determined adiponectin and leptin levels in adolescents born by women with type 1 diabetic (T1D) or non-diabetic mothers, and determined associations between adiponectin and leptin levels in adolescence and the magnitude of intrauterine hyperglycemia.

RESEARCH DESIGN AND METHODS

We measured serum adiponectin and leptin and calculated leptin to adiponectin ratio (LAR) in 271 offspring of T1D women (index offspring) (13-20years), and 297 matched control offspring. Anthropometry included total body fat (TBF) by dual-energy X-ray absorptiometry and an oral glucose tolerance test.

RESULTS

Adiponectin levels were lower in index females (-8.0% (95% CI; -13.9, -1.6)), but not in index males (0.4% (95% CI; -7.3, 8.6)). Leptin levels were approximately 30% higher in index than control offspring, irrespective of gender. In males, this was seen despite similar TBF in index and control offspring. LAR was increased in index offspring (both males and females) compared with control offspring. There were no association between offspring adiponectin and maternal HbA1c levels in pregnancy. Leptin and LAR seemed to be associated with third trimester HbA1c levels in females in unadjusted, but not adjusted analyses.

CONCLUSION

Male and female offspring of women with T1D demonstrated increased serum leptin and LAR, whereas serum adiponectin was reduced in females only. These results suggest that abnormal regulation of adipokines is a consequence of being born to mothers with T1D. No direct association between maternal glycemic control and adiponectin and leptin levels or LAR in the adolescence was found.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01559181.

Obesity and hypertension

Obesity and in particular the excessive visceral fat distribution is accompanied by several alterations at hormonal, inflammatory and endothelial level. These alterations induce a stimulation of several other mechanisms that contribute to the hypertensive state and on the other side to increase the cardiovascular morbidity. In these chapter we will examine the main mechanisms of obesity and obesity-related hypertension and in particular the role of sympathetic nervous system, the alterations of the renal function and at the microvascular level. We will also depict the role of insulin resistance as factor stimulating and potentiating the other mechanisms. The second part will be focalized on the major target organ damage linked with obesity and obesity-related hypertension. We will finally describe the management and treatment of obesity and the antihypertensive drug therapies more effective in hypertensive obeses.

Leptin is associated with heart rate recovery in Chinese hypertensive patients

Elevated serum leptin concentrations are closely related to sympathetic nervous system activation in essential hypertension (EH); however, it is not clear whether or not they are associated with parasympathetic nervous system impairment in EH. Heart rate recovery (HRR) is a reproducible method used to assess parasympathetic activity. This study aimed to investigate the relationship between serum leptin and HRR in Chinese untreated EH patients. This was a cross-sectional study enrolling 471 Chinese EH patients (205 men, 266 women; mean age 63.1 years). HRR was calculated during an incremental cardiopulmonary exercise test. Simple and multiple regression analyses were used to assess the correlation between serum leptin level and HRR value. Serum leptin levels elevated with increasing BP values. Moreover, univariate analysis revealed that the HRR value was negatively correlated with serum leptin (r = -0.037, P < 0.01). In multiple regression analysis, the age-adjusted serum leptin level was negatively correlated with HRR (β = -0.268, P < 0.01). Serum leptin remained negatively associated with HRR (β = -0.017, P < 0.01) after further adjustments for factors including age, systolic blood pressure, total cholesterol, and several factors that correlated with HRR. Our findings demonstrated that a raised serum leptin concentration is related to HRR blunt, which suggests that the role of leptin in the development of EH might be associated with impairment of the parasympathetic nervous system as well.

36 h fasting of young men influences adipose tissue DNA methylation of LEP and ADIPOQ in a birth weight-dependent manner

Background

Subjects born with low birth weight (LBW) display a more energy-conserving response to fasting compared with normal birth weight (NBW) subjects. However, the molecular mechanisms explaining these metabolic differences remain unknown. Environmental influences may dynamically affect epigenetic marks, also in postnatal life. Here, we aimed to study the effects of short-term fasting on leptin (LEP) and adiponectin (ADIPOQ) DNA methylation and gene expression in subcutaneous adipose tissue (SAT) from subjects with LBW and NBW.

Methods

Twenty-one young LBW men and 18 matched NBW controls were studied during 36 h fasting. Eight subjects from each group completed a control study (overnight fast). We analyzed SAT LEP and ADIPOQ methylation (Epityper MassARRAY), gene expression (q-PCR), and adipokine plasma levels.

Results

After overnight fast (control study), LEP and ADIPOQ DNA methylation levels were higher in LBW compared to those in NBW subjects (p ≤ 0.03) and increased with 36 h fasting in NBW subjects only (p ≤ 0.06). Both LEP and ADIPOQ methylation levels were positively associated with total body fat percentage (p ≤ 0.05). Plasma leptin levels were higher in LBW versus NBW subjects after overnight fasting (p = 0.04) and decreased more than threefold in both groups after 36 h fasting (p ≤ 0.0001).

Conclusions

This is the first study to demonstrate that fasting induces changes in DNA methylation. This was shown in LEP and ADIPOQ promoters in SAT among NBW but not LBW subjects. The altered epigenetic flexibility in LBW subjects might contribute to their differential response to fasting, adipokine levels, and increased risk of metabolic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0340-8) contains supplementary material, which is available to authorized users.

Adiponectin protects against incident hypertension independent of body fat distribution: observations from the Dallas Heart Study

BACKGROUND

Excess adipose tissue has been implicated in the pathogenesis of insulin resistance and atherosclerosis and is a key risk factor for blood pressure (BP) elevation. However, circulating levels of adiponectin, a protein produced by adipose tissue and widely implicated in the pathogenesis of insulin resistance and atherosclerosis, are inversely proportional to adiposity. The relationship between adiponectin and incident hypertension has not been determined in the general US population.

METHODS

Normotensive participants (n = 1233) enrolled in the Dallas Heart Study, a multiethnic, probability-based population sample of Dallas County adults were followed for median of 7 years. Retroperitoneal, intraperitoneal, visceral, and subcutaneous adipose tissue were measured at baseline by magnetic resonance imaging. Liver fat content was measured by ¹ H-magnetic resonance spectroscopy. Relative risk regression was used to determine the association of adiponectin with incident hypertension after adjustment for age, race, sex, BMI, smoking, diabetes, baseline systolic BP, total cholesterol, and regional fat depot.

RESULTS

Of the 1233 study participants (median age 40 years, 40% black, and 56% women), 391 (32%) had developed hypertension over a median follow-up of 7 years. Adiponectin levels were associated with reduced risk of incident hypertension (RR 0.81, 95% CI [0.68-0.96]) in the fully adjusted model, which included liver fat. Similar results were observed after adjustment for subcutaneous or visceral fat depots when tested individually or simultaneously in the model.

CONCLUSION

Our study suggested a protective role of adiponectin against incident hypertension independent of body fat distribution.

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

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

Markers of oxidative stress in obese men with and without hypertension

OBJECTIVES

The aim of our study was to investigate if the 24-hour excretion of the urinary markers for oxidative stress to DNA and RNA, measured as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), respectively, were increased in obese individuals with or without hypertension compared to lean controls.

METHODS

A total of 63 obese hypertensive men (obeseHT), 40 obese normotensive men (obeseNT) and 27 lean normotensive men (leanNT) were included in the study. Body mass index (BMI) was between 20.0 and 24.9 kg/m² in leanNT participants and ≥30 kg/m² in obese participants. Hypertension was defined as a mean 24-hour systolic ambulatory blood pressure (AMBP) ≥ 130 mmHg or a mean 24-hour diastolic AMBP ≥80 mmHg and normotension as mean 24-hour AMBP <130/80 mmHg. Twenty-four hour urinary 8-oxoGuo and 8-oxodG excretion (nmol/24 h) were measured by a validated liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS).

RESULTS

Urinary 8-oxoGuo excretion was (median and [interquartile range]) 30.8 [27.8-32.2] nmol/24 h in leanNT, 36.8 [31.3-40.2] nmol/24 h in obeseNT and 40.6 [31.7-48.5] nmol/24 h in obeseHT. The difference was statistically significant (p = .002) and post hoc tests showed a significant difference between leanNT and obeseHT (p = .001) as well as obeseNT (p = .002), whereas the two obese groups did not differ (p = .6). No statistically significant differences in 8-oxodG concentrations were observed between the three groups (p = .3).

CONCLUSION

The measurement of urinary excretion of 8-oxoGuo suggests that obesity in men, but not hypertension, is associated with increased oxidative damage to RNA.

Low adiponectin levels at baseline and decreasing adiponectin levels over 10 years of follow-up predict risk of the metabolic syndrome

AIM

Adiponectin is the most abundant adipokine and may play a key role in the interplay between obesity, inflammation, insulin resistance and the metabolic syndrome (MetS). Thus, this large population-based cohort investigated whether adiponectin at baseline and/or a decrease in adiponectin during follow-up is associated prospectively with the risk of incident MetS.

METHODS

Using a prospective study design, the development of MetS was examined in 1134 healthy participants from the community. Plasma adiponectin was measured at study entry and again after a median follow-up of 9.4 years (IQR: 9.2-9.7). During follow-up, 187 participants developed MetS, and 439 presented with at least two components of MetS.

RESULTS

During follow-up, adiponectin decreased in participants who developed MetS, whereas adiponectin was increased in those who did not develop MetS (P<0.001). Those with low adiponectin levels (quartile 1) at baseline had an increased risk of developing MetS (OR: 2.92, 2.08-6.97; P<0.001) compared with those with high levels (quartile 4). After adjusting for confounding variables, low adiponectin levels at baseline remained independently associated with MetS (OR: 2.24, 1.11-4.52; P=0.017). Similarly, participants with a decrease in adiponectin during follow-up also had an increased risk of MetS (OR: 2.96, 2.09-4.18; P<0.001). This association persisted after multivariable adjustments, including for baseline adiponectin (OR: 4.37, 2.77-6.97; P<0.001). Finally, adiponectin levels at follow-up were inversely associated with an increase in the number of components of MetS (P<0.001); geometric mean adiponectin levels were 9.5mg/L (95% CI: 9.0-10.0) for participants with no components vs 7.0mg/L (95% CI: 6.3-7.9) for those with four to five components.

CONCLUSIONS/INTERPRETATION

Low plasma adiponectin levels at baseline and decreasing adiponectin levels during follow-up are both associated with an increased risk of MetS.

An update on the role of adipokines in arterial stiffness and hypertension

Adipokines are hormones produced by adipocytes and have been involved in multiple pathologic pathways, including inflammatory and cardiovascular complications in essential hypertension. Arterial stiffness is a frequent vascular complication that represents increased cardiovascular risk in hypertensive patients. Adipokines, such as adiponectin, leptin and resistin, might be implicated in hypertension, as well as in vascular alterations associated with this condition. Arterial stiffness has proven to be a predictor of cardiovascular events. Obesity and target-organ damage such as arterial stiffness are features associated with hypertension. This review aims to update the association between adipokines and arterial stiffness in essential and resistant hypertension (RHTN).

Changes in IGF-I, urinary free cortisol and adipokines during dronabinol therapy in anorexia nervosa: Results from a randomised, controlled trial

OBJECTIVE

Anorexia nervosa (AN) is characterised by complex neuroendocrine disturbances due to severe underweight, physical hyperactivity and purging behaviour. Cannabinoid agonists are used to palliate cachexia of various causes, but their interactions with the hormonal systems that are involved in energy metabolism have not been previously described in humans. Therefore we found it of interest to assess interactions between the synthetic cannabinoid agonist dronabinol and insulin-like growth factor I (IGF-I), urinary free cortisol (UFC) and adipokines in patients with chronic AN.

DESIGN

This was a prospective, double-blind randomised crossover study, conducted at a specialised care centre for eating disorders. The results are based on twenty-four adult women with chronic AN, who completed the study. The participants received dronabinol (oral capsules, 5mg daily) and matching placebo over four weeks, separated by a four-week washout period. Bioactive IGF was determined by a cell-based bioassay, whereas total IGF-I, IGFBP-2 and -3 and the two adipokines leptin and adiponectines were measured by immunoassays. The UFC excretion was determined by mass spectrometry.

RESULTS

As previously reported, dronabinol treatment caused a small, yet significant increase in BMI as compared to placebo (+0.23 kg/m(2); P = 0.04). This modest weight gain predicted a corresponding increase in bioactive IGF-I, while the amount of daily energy expenditure due to physical activity had a comparable but opposite effect. Nevertheless, neither IGF-I, bioactive IGF nor the IGFBPs levels changed significantly during dronabinol intervention as compared to placebo. Adiponectin also remained unaffected by the weight gain, whereas plasma leptin showed a transient increase at three weeks (P < 0.05). UFC levels were decreased during dronabinol intervention.

CONCLUSION

Our results showed that low-dosage therapy with the synthetic cannabinoid agonist dronabinol affected neither the concentration nor the activity of the circulating IGF-system in women with severe and chronic AN. However, our results suggest that such treatment may alleviate the increased hypothalamic-pituitary-adrenal axis activity seen in these patients.

Overweight, adipocytokines and hypertension: a prospective population-based study

OBJECTIVE

The adipocytokines, leptin, adiponectin, and interleukin-6, which stimulate liver C-reactive protein (CRP) production, are regarded as potential candidate intermediates between adipose tissue and overweight-induced hypertension.

METHODS

We examined the associations between leptin, adiponectin, and CRP levels with both prevalent and 5-year incident hypertension (IHT) in a general population of Danish adults (n = 5,868, 51.3% women, mean age 45.8 ± 7.9 years).

RESULTS

We recorded 2195 prevalent and 379 incident cases of hypertension. In models including leptin, CRP, adiponectin, sex, age, lifestyle risk factors, lipids, insulin, hemoglobin A1c, and in the incident model also baseline heart rate and blood pressure, only leptin of the three candidate intermediates was significantly associated with both prevalent and IHT [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.06-1.32, P = 0.002, and OR = 1.24, 95% CI 1.01-1.54, P = 0.044] for one standard deviation increase in log-transformed leptin levels, respectively. Log-transformed CRP was associated with prevalent (OR = 1.16, 95% CI 1.07-1.26, P < 0.001) but not IHT (OR = 0.98, 95% CI 0.84-1.14, P = 0.76). Log-transformed adiponectin was neither associated with prevalent nor IHT (OR = 0.94, 95% CI 0.87-1.02, P = 0.11 and OR = 0.93, 95% CI 0.80-1.08, P = 0.33). Comparing the lowest with the highest quintile of sex-specific BMI levels, there was an almost two-fold increase in IHT (OR = 1.89, 95% CI 1.10-3.25, P = 0.023) in the fully adjusted model. The population attributable risk estimate of IHT owing to overweight was 31%.

CONCLUSION

Leptin, but not adiponectin or CRP, may play a mediating role in overweight-induced hypertension. However, as BMI was a strong independent predictor of hypertension, other factors than leptin must be involved in the pathogenesis of overweight-related hypertension.

Exercise addiction in men is associated with lower fat-adjusted leptin levels

OBJECTIVE

To test a hypothesized association between resting leptin levels (adjusted for body fat percentage) and symptoms of primary exercise addiction.

DESIGN

Cross-sectional design.

SETTING

Habitual amateur exercisers participating in running, fitness, weight training, and biking.

PARTICIPANTS

Twenty men with exercise addiction as defined by the Exercise Addiction Inventory (EAI scores 24-30) and 20 men in an exercise control group (EAI scores 6-16) matched on body mass index.

MAIN OUTCOME MEASURES

Plasma leptin and sex hormones were measured in blood samples collected under fasting and resting conditions. Body composition was assessed by dual-energy x-ray absorptiometry. Eating disorder symptoms were identified by the Eating Disorder Inventory 2.

RESULTS

The exercise addiction group had significantly (P < 0.001) lower leptin levels (1.1 μg/L, SD = 1.3) than controls (4.3 μg/L, SD = 2.9). Even when adjusted for body fat percentage, the addiction group had significantly (P < 0.001) lower leptin levels (0.1 μg/L, SD = 0.1) than the controls (0.2 μg/L, SD = 0.1). Body fat-adjusted leptin correlated with free bioavailable testosterone, but it was only significant in nonaddictive exercisers. None of the exercisers seemed to suffer from an eating disorder.

CONCLUSIONS

This is the first study showing that excessive training in exercise addiction is associated with low levels of body fat-adjusted leptin levels.

CLINICAL RELEVANCE

Hypoleptinemia could be involved in the pathogenesis of exercise addiction. However, further studies are needed to explore the potential causal relationship.

Effect of dronabinol therapy on physical activity in anorexia nervosa: a randomised, controlled trial

PURPOSE

The level of physical activity is inappropriately high in up to 80% of the patients suffering of anorexia nervosa (AN), as a result of conscious efforts to lose weight, affect regulation and biological adaptive changes to starvation induced by hypothermia and neuroendocrine mechanisms. The purposes of this paper were to (1) assess the effect of dronabinol-a synthetic cannabinoid agonist-on physical activity in patients with chronic and stable AN, and to (2) unravel the role of leptin and cortisol in this process.

METHODS

This prospective, randomised, double-blind, crossover study was conducted at a specialised care centre for eating disorders. Twenty-four adult women with AN of at least 5-year duration received either the dronabinol-placebo or placebo-dronabinol sequence. Physical activity was monitored during the fourth week of each intervention. Body weight, leptin and urinary free cortisol excretion were measured repeatedly during the trial. Changes in behavioural dimensions related to AN were assessed by Eating Disorder Inventory-2.

RESULTS

The total duration of physical activity did not change, while its average intensity increased by 20% (P = 0.01) during dronabinol therapy, resulting in an increased energy expenditure with 68.2 kcal/day (P = 0.01) above placebo.

CONCLUSIONS

This randomised, double-blind study revealed that cannabinoid agonist treatment was associated with a modest increase in physical activity in adult women with severe and longstanding AN. Additionally, we detected a strong relationship between the circulating levels of leptin and physical activity in these chronically undernourished patients.

Association of adiponectin with type 2 diabetes and hypertension in African American men and women: the Jackson Heart Study

Background

Adiponectin is a biomarker that is associated with type 2 diabetes and hypertension. Lower circulating level is a risk factor. Higher levels are protective. African Americans have a higher prevalence of type 2 diabetes and hypertension and lower levels of adiponectin when compared to other racial/ethnic groups. Little is known about the association of adiponectin on these health outcomes among African Americans. The purpose of the study was to assess the association of adiponectin on type 2 diabetes and hypertension likelihood among African American men and women in the Jackson Heart Study.

Methods

Separate multivariate logistic regressions were conducted stratified by sex based on cross-sectional data with type 2 diabetes and hypertension as the outcomes. Adiponectin was divided into four quartiles with the highest quartile as the reference. Data was collected from 2000-2004 on 3,663 participants. Data analysis was conducted in calendar year 2014. Two- tailed P < .05 was established as level of significance.

Results

In the adjusted multivariate models, adiponectin level was inversely associated with type 2 diabetes among women (odds ratio [OR], 95% confidence interval [CI] = 1.47, [1.02, 2.11], P = .04). There was no association among men. Women with the lowest level of adiponectin were less likely to be hypertensive (OR, 95% CI = 0.66, [0.46, 0.95], p = .02). There was no association among men.

Conclusion

Findings reveal differential associations between levels of adiponectin with type 2 diabetes and hypertension likelihood among African American women. More research is needed to elucidate this differential association.

Higher serum concentrations of N-terminal pro-B-type natriuretic peptide associate with prevalent hypertension whereas lower associate with incident hypertension

Background

The role of the natriuretic peptides (NPs) in hypertension is complex. Thus, a higher blood NP concentration is a robust marker of pressure-induced cardiac damage in patients with hypertension, whereas genetically elevated NP concentrations are associated with a reduced risk of hypertension and overweight individuals presumably at high risk of hypertension have lower NP concentrations.

Objective

To investigate the associations between serum N-terminal pro-B-type natriuretic peptide (NT-proBNP), used as a surrogate marker for active BNP, and prevalent as well as 5-year incident hypertension in a Danish general population sample.

Methods

Cross-sectional and prospective population-based study.

Results

At baseline, among 5,307 participants (51.3% women, mean age 46.0±7.9 years) with a complete set of data, we recorded 1,979 cases with prevalent hypertension (PHT). Among 2,389 normotensive participants at baseline with a complete set of data, we recorded 324 cases with incident hypertension (IHT) on follow-up 5 years later. In models adjusted for age, sex, lifestyle, social, dietary, anthropometric, pulmonic, lipid, metabolic and renal risk factors, as well as heart rate and baseline blood pressure (only incident model), one standard deviation increase in baseline log-transformed NT-proBNP concentrations was on one side associated with a 21% higher risk of PHT (odds ratio [OR]: 1.21 [95% confidence interval (CI): 1.13-1.30], P<0.001), and on the other side with a 14% lower risk of IHT (OR: 0.86 [95%CI:0.76-0.98], P = 0.020).

Conclusions

Higher serum concentrations of NT-proBNP associate with PHT whereas lower concentrations associate with IHT. This suggests that a lower amount of circulating BNP, resulting in diminished vasodilation and natriuresis, could be involved in the pathogenesis of hypertension in its early stages.

Leptin Reference Values and Cutoffs for Identifying Cardiometabolic Abnormalities in the Spanish Population

INTRODUCTION AND OBJECTIVES

Estimate leptin reference values and calculate leptinemia cutoff values for identifying cardiometabolic abnormalities in Spain.

METHODS

Cross-sectional study carried out between 2008 and 2010 in 11 540 individuals representing the Spanish population aged ≥ 18 years. Data were obtained by standardized physical examination and analyses were performed at a central laboratory. Leptinemia was measured using ELISA. Cardiometabolic abnormality was defined as the presence of at least two of the following: high blood pressure, high triglycerides, reduced high density lipoprotein cholesterol, high insulin resistance values, and elevated C-reactive protein and glucose.

RESULTS

Leptin values were higher in women than men (geometric mean, 21.9 and 6.6 ng/mL; P<.001). The median [interquartile range] was 24.5 [14.1-37.0] ng/mL in women, and 7.2 [3.3-14.3] ng/mL in men. In the multivariate analysis, leptin was significantly associated with anthropometric measures, insulin, and C-reactive protein, and inversely associated with age, smoking, and physical activity in women (r(2)=0.53; P<.001) and in men (r(2)=0.61; P<.001). The leptin values that identified cardiometabolic abnormality were 23.75 ng/mL in women (area under the curve, 0.722; sensitivity, 72.3%; specificity, 58.7%) and 6.45 ng/mL in men (area under the curve, 0.716; sensitivity, 71.4%; specificity, 60.2%).

CONCLUSIONS

These results facilitate the interpretation of leptin values in clinical and population studies. Leptin has moderate sensitivity and specificity for identifying cardiometabolic abnormalities.

Adiponectin is not associated with blood pressure in normotensives and untreated hypertensives with normal kidney function

The role of adiponectin in hypertension is still a matter of debate. Obtained conflicting results could be mostly explained with diversity of subjects included in different studies. Our aim was to analyze association of adiponectin with blood pressure (BP) in a group of normotensive and untreated hypertensive subjects. Participants (N=257) were selected from a random sample of 2487 subjects enrolled in an observational cross-sectional study. Subjects with diabetes and chronic kidney diseases were excluded. BP was measured using Omron M6 device following ESH/ESC guidelines. Adiponectin concentration was determined by ELISA. There were no differences in adiponectin values (mg/L) between hypertensives and normotensives (median 9.75; iqr: 7.44-17.88 vs 11.35; iqr: 7.43-12.63; P=0.17). On univariate linear regression adiponectin was not associated with systolic or diastolic BP (P>0.05). Furthermore, multivariate analysis did not show significant contribution of log-transformed adiponectin either to systolic (β=-0.040; P=0.43) or diastolic BP (β=0.066; P=0.33). In our group of normotensives and untreated hypertensives with normal kidney function adiponectin was not associated with BP even after adjustment for other risk factors. Our results and conclusions should not be extrapolated to subjects with other characteristics.

Dronabinol in severe, enduring anorexia nervosa: a randomized controlled trial

OBJECTIVE

The evidence for pharmacological treatment of severe, longstanding anorexia nervosa (AN) is sparse and the few controlled pharmacologic studies have focused on a narrow range of drugs. The aim of the present study was to investigate the effects of treatment with a synthetic cannabinoid agonist on body weight and eating disorder-related psychopathological personality traits in women with severe, enduring AN.

METHOD

This add-on, prospective, randomized, double blind, controlled crossover study was conducted between 2008 and 2011 at a specialized care center for eating disorders. Twenty-five women over 18 years with AN of at least 5 years duration were randomized to treatment with either dronabinol-placebo or placebo-dronabinol. In addition to the standardized baseline therapeutic regime, the participants received dronabinol, 2.5 mg twice daily for 4 weeks and matching placebo for 4 weeks, separated by a 4-week wash-out period. Primary outcome was the mean change in body weight. Secondary outcome was score changes on the Eating Disorder Inventory-2 (EDI-2). Data were analyzed for the 24 patients who completed the trial.

RESULTS

During dronabinol treatment, participants gained 0.73 kg (t = 2.86, df = 22, p < 0.01) above placebo without significant psychotropic adverse events. Dronabinol significantly predicted weight gain in a multiple linear regression including EDI-2 body dissatisfaction score and leptin. EDI-2 subscale scores showed no significant changes over time.

DISCUSSION

Dronabinol therapy was well tolerated. During four weeks of exposure it induced a small but significant weight gain in the absence of severe adverse events.

Adiponectin levels and the risk of hypertension: a systematic review and meta-analysis

Animal studies and small controlled studies in humans suggest that adiponectin may regulate blood pressure via brain-mediated and endothelium-mediated mechanisms. We performed a systematic review and meta-analysis to evaluate the epidemiological evidence on plasma adiponectin levels and hypertension in free-living adult population. A systematic search of MEDLINE and EMBASE, up to February 2013, identified 43 nonprospective and 5 prospective studies that included 17 598 adults (8220 with hypertension; mean age 19-69 years; and mean body mass index 22-38 kg/m(2)). Two investigators independently extracted data on adiponectin levels by hypertension status and dose-response relationship. We used a random-effects model to compute the weighted mean difference in adiponectin levels between adults with hypertension and normotensive adults and a 2-stage generalized least-square trend methods to compute the odds ratio of hypertension per 1 µg/mL increase in adiponectin. Adults with hypertension had 1.64 µg/mL (95% confidence interval, -2.07, -1.21) lower adiponectin levels than normotensive adults. Every 1 µg/mL increase in adiponectin levels was associated with 6% reduced risk of hypertension (95% confidence interval, 0.92, 0.97). These findings were consistent across study design and characteristics, including age, sex, and body mass index (P>0.05). However, our meta-analysis was limited by unexplained large between-study heterogeneity, a small number of prospective studies, and selective reporting of dose-response data. In conclusion, epidemiological evidence suggests that plasma adiponectin level is a biomarker and possible mediator in the development of adiposity-related hypertension. The question remains as to adiponectin as a potential therapeutic target and its relationship with other adipokines in blood pressure regulation.

New Obesity Indices and Adipokines in Normotensive Patients and Patients With Hypertension

We compared the obesity parameters and selected adipokines—leptin, adiponectin, and resistin—in obese patients with hypertension and normotensive patients. A total of 67 nondiabetic obese outpatients were divided into 2 groups: A–hypertensive and B–normotensive. Serum levels of leptin, adiponectin, resistin, and insulin were measured. Weight, height, waist circumference, and hip circumference were measured to calculate waist-to-hip ratio (WHR), weight-to-height ratio, visceral adiposity index, and body adiposity index (BAI). Among patients with hypertension, significant positive correlations were observed between leptin and body mass index and BAI ( r = .31 and r = .63, respectively). In normotensive patients, leptin positively correlated with BAI ( r = .73, P < .01) and negatively with WHR ( r = −.55, P < .0001); adiponectin negatively correlated with WHR ( r = .38, P < .01) and BAI ( r = .52; P < .0001), and resistin negatively correlated with WHR ( r = −.36, P < .05). In conclusion, visceral obesity and leptin are associated with hypertension in obese patients.

Higher leptin is associated with hypertension: the Multi-Ethnic Study of Atherosclerosis

Adipokines are secreted from adipose tissue, influence energy homeostasis and may contribute to the association between obesity and hypertension. Among 1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis, we examined associations between blood pressure and leptin, tumor necrosis factor-α (TNFα), resistin and total adiponectin. The mean age and body mass index (BMI) was 64.7 years and 28.1, respectively, and 50% were female. After adjustment for risk factors, a 1-s.d.-increment higher leptin level was significantly associated with higher systolic (5.0 mm Hg), diastolic (1.9), mean arterial (2.8) and pulse pressures (3.6), as well as a 34% higher odds for being hypertensive (P<0.01 for all). These associations were not materially different when the other adipokines, as well as BMI, waist circumference or waist-to-hip ratio, were additionally added to the model. Notably, the associations between leptin and hypertension were stronger in men, but were not different by race/ethnic group, BMI or smoking status. Adiponectin, resistin and TNFα were not independently associated with blood pressure or hypertension. Higher serum leptin, but not adiponectin, resistin or TNFα, is associated with higher levels of all measures of blood pressure, as well as a higher odds of hypertension, independent of risk factors, anthropometric measures and other selected adipokines.