High plasma leptin levels are associated with impaired diastolic function in patients with coronary artery disease

Glutamine supplementation can reduce some atherosclerosis markers after exhaustive exercise in young healthy males

OBJECTIVES

Glutamine can be beneficial to athletes for its antiinflammatory and antioxidant effects. The present study was designed to investigate the effect of glutamine supplementation on some atherosclerosis markers after exhaustive exercise in young healthy males.

METHODS

In an intervention study, 30 healthy males (case = 15 and control = 15) were randomly assigned into two groups. For 14 d, the intervention group received 0.3 g of glutamine per kilogram of body weight per day, with 25 g of sugar in 250 mL of water, and the control group received 25 g of sugar per 250 mL of water. At the end of the intervention, the participants completed one session of exhaustive exercise, and then fasting blood samples were taken to test serum levels of atherosclerosis markers.

RESULTS

In the intervention group, the serum levels of leptin, cholesterol, and oxidized low-density lipoprotein were lower than in the control group after 2 wk of glutamine supplementation (P < 0.05). Interleukin-6 serum levels were lower in the intervention group compared to the control group after supplementation, but not significantly. Serum levels of leptin, interleukin-6, cholesterol, and oxidized low-density lipoprotein, as well as the ratio of oxidized low-density lipoprotein to high-density lipoprotein, were significantly decreased in the intervention group compared to the control group after exhaustive exercise (P < 0.05).

CONCLUSIONS

Glutamine supplementation has beneficial effects for athletes, particularly those doing strenuous physical exercise, through reducing atherosclerosis-related biomarkers and elevating serum adiponectin levels, and it can potentially play a role in decreasing the initiation and progression of atherosclerosis.

Association of Adiponectin, Leptin and Resistin Plasma Concentrations with Echocardiographic Parameters in Patients with Coronary Artery Disease

The imbalanced network of adipokines may contribute to the development of systemic low-grade inflammation, metabolic diseases and coronary artery disease (CAD). In the last decade, three classic adipokines—adiponectin, leptin and resistin—have been of particular interest in studies of patients with CAD due to their numerous properties in relation to the cardiovascular system. This has directed our attention to the association of adipokines with cardiac structure and function and the development of heart failure (HF), a common end effect of CAD. Thus, the purpose of this study was to analyse the associations of plasma concentrations of adiponectin, leptin and resistin with parameters assessed in the echocardiographic examinations of CAD patients. The presented study enrolled 167 Caucasian patients (133 male; 34 female) with CAD. Anthropometric, echocardiographic and basic biochemical measurements, together with plasma concentrations of adiponectin, leptin and resistin assays, were performed in each patient. Adiponectin concentrations were negatively associated with left ventricular ejection fraction (LVEF) and shortening fraction (LVSF), and positively associated with mitral valve E/A ratio (E/A), left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter LVESD, and left atrium diameter (LAD). Resistin concentrations were negatively associated with E/A. Leptin concentrations, although correlated with HF severity assessed by the New York Heart Association (NYHA) Functional Classification, were not independently associated with the echocardiographic parameters of cardiac structure or function. In conclusion, adiponectin and resistin, but not leptin, are associated with the echocardiographic parameters of cardiac remodelling and dysfunction. These associations suggest that adiponectin and resistin might be involved in mechanisms of cardiac remodelling or compensative response. We also suggest the possible benefits of adiponectin and resistin level measurements in the monitoring of patients with CAD.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

Leptin Levels are Associated with Subclinical Cardiac Dysfunction in Obese Adolescents

PURPOSE

The purposes of this study were to use speckle tracking echocardiography to confirm the influence of obesity on cardiac functions and to assess their relationships with leptin and uric acid levels in obese adolescents.

METHODS

Eighty-one participants aged 16-19 years were recruited and classified as either non-obese (n = 30) or obese (n = 51). Global longitudinal strain (GLS), leptin and uric acid levels for each group were assessed and compared. The data from obese participants were then compared based on their leptin levels and analyzed for correlation using regression analysis.

RESULTS

The obese group had significantly lower absolute GLS compared to the non-obese group (19.10 ± 0.30 versus 21.10 ± 0.30%, p < 0.001). In obese group, subclinical cardiac dysfunction was worse in the hyperleptinemic group than that of the normoleptinemic group (p = 0.03). Multivariate regression analysis showed that leptin and triglyceride levels were negatively associated with absolute GLS. Leptin could predict the absolute GLS with β = -0.35 (p = 0.02).

CONCLUSION

Subclinical left ventricular systolic dysfunction was found in obese adolescents, while GLS was worse in the hyperleptinemic subjects. Leptin, but not uric acid, levels were associated with a worsening of GLS.

Plasma concentration and expression of adipokines in epicardial and subcutaneous adipose tissue are associated with impaired left ventricular filling pattern

Background

Adipokines in serum derive mainly from subcutaneous and visceral adipose tissues. Epicardial adipose tissue (EAT), being a relatively small but unique fat depot, probably does not make an important contribution to systemic concentrations of adipokines. However, proximity of EAT to cardiac muscle and coronary arteries allows cells and proteins to penetrate between tissues. It is hypothesized that overexpression of proinflammatory cytokines in EAT plays an important role in pathophysiology of the heart. The aim of the study was to analyze the relationship between echocardiographic heart parameters and adipokines in plasma, epicardial, and subcutaneous fat in patients with obesity and type 2 diabetes mellitus (T2DM). Additionally, we evaluate proinflammatory properties of EAT by comparing that depot with subcutaneous adipose tissue.

Methods

The study included 55 male individuals diagnosed with coronary artery disease (CAD) who underwent planned coronary artery bypass graft. Plasma concentrations of leptin, adiponectin, resistin, visfatin, apelin, IL-6, and TNF-α, as well as their mRNA and protein expressions in EAT and subcutaneous adipose tissue (SAT) were determined.

Results

Obesity and diabetes were associated with increased leptin and decreased adiponectin plasma levels, higher protein expression of leptin and IL-6 in SAT, and higher visfatin protein expression in EAT. Impaired left ventricular (LV) diastolic function was associated with increased plasma concentrations of leptin, resistin, IL-6, and adiponectin, as well as with increased expressions of resistin, apelin, and adiponectin in SAT, and leptin in EAT.

Conclusions

Obesity and T2DM in individuals with CAD have a limited effect on adipokines. Expression of adipokines in EAT and SAT is linked to certain heart parameters, however diastolic dysfunction of the LV is strongly associated with circulating adipokines.

Association between hyperleptinemia and cardiovascular outcomes in patients with coronary artery disease

Purpose

Hyperleptinemia has been independently associated with human cardiovascular (CV) diseases. Accordingly, we evaluate the association between serum leptin and future CV events in patients with coronary artery disease (CAD).

Patients and methods

This study enrolled 98 patients with CAD from January to December 2012. The primary endpoint included incidences of major adverse CV events and hospitalization. Patients follow-up had been completed on June 30, 2017.

Results

After a median follow-up of 52 months, 43 CV events had occurred. Patients with CV events had higher systolic blood pressure (P = 0.030), total cholesterol (P = 0.034), C-reactive protein (P = 0.018), and serum leptin levels (P = 0.001) than those without CV events. Kaplan–Meier analysis showed greater cumulative incidences of CV events in the high leptin group (median leptin concentration >6.03 ng/mL) than in the low leptin group (log-rank P = 0.012). Multivariate Cox regression analysis showed that triglyceride (HR: 1.010; 95% CI: 1.001–1.018; P = 0.022) and leptin levels (HR: 1.054; 95% CI: 1.026–1.082; P < 0.001) were independently associated with CV events in patients with CAD.

Conclusion

Serum leptin levels could serve as a biomarker for future CV events in patients with CAD.

Leptin, cardiovascular diseases and type 2 diabetes mellitus

Leptin, an adipokine that is implicated in the control of food intake via appetite suppression, may also stimulate oxidative stress, inflammation, thrombosis, arterial stiffness, angiogenesis and atherogenesis. These leptin-induced effects may predispose to the development of cardiovascular diseases. In the present review we discuss the evidence linking leptin levels with the presence, severity and/or prognosis of both coronary artery disease and non-cardiac vascular diseases such as stroke, carotid artery disease, peripheral artery disease (PAD) and abdominal aortic aneurysms (AAA) as well as with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). Leptin levels have been positively associated with the presence, severity, extent and lesion complexity of coronary atherosclerosis as well as with the presence, severity and poor clinical outcomes of both ischemic and hemorrhagic strokes. But conflicting results also exist. Furthermore, leptin was reported to independently predict common carotid intima-media thickness and carotid plaque instability. A link between hyperleptinemia and PAD has been reported, whereas limited data were available on the potential association between leptin and AAA. Elevated leptin concentrations have also been related to CKD incidence and progression as well as with insulin resistance, T2DM, micro- and macrovascular diabetic complications. Statins and antidiabetic drugs (including sitagliptin, metformin, pioglitazone, liraglutide and empagliflozin) may affect leptin levels. Further research is needed to establish the potential use (if any) of leptin as a therapeutic target in these diseases.

Association of Circulating Adipokines With Echocardiographic Measures of Cardiac Structure and Function in a Community-Based Cohort

BACKGROUND

Adipokines mediate cardiometabolic risk associated with obesity but their role in the pathogenesis of obesity-associated heart failure remains uncertain. We investigated the associations between circulating adipokine concentrations and echocardiographic measures in a community-based sample.

METHODS AND RESULTS

We evaluated 3514 Framingham Heart Study participants (mean age 40 years, 53.8% women) who underwent routine echocardiography and had select circulating adipokines measured, ie, leptin, soluble leptin receptor, fatty acid-binding protein 4, retinol-binding protein 4, fetuin-A, and adiponectin. We used multivariable linear regression, adjusting for known correlates (including weight), to relate adipokine concentrations (independent variables) to the following echocardiographic measures (dependent variables): left ventricular mass index, left atrial diameter in end systole, fractional shortening, and E/e'. In multivariable-adjusted analysis, left ventricular mass index was inversely related to circulating leptin and fatty acid-binding protein 4 concentrations but positively related to retinol-binding protein 4 and leptin receptor levels (P≤0.002 for all). Left atrial end-systolic dimension was inversely related to leptin but positively related to retinol-binding protein 4 concentrations (P≤0.0001). E/e' was inversely related to leptin receptor levels (P=0.0002). We observed effect modification by body weight for select associations (leptin receptor and fatty acid-binding protein 4 with left ventricular mass index, and leptin with left atrial diameter in end systole; P<0.05 for interactions). Fractional shortening was not associated with any of the adipokines. No echocardiographic trait was associated with fetuin-A or adiponectin concentrations.

CONCLUSIONS

In our cross-sectional study of a large, young to middle-aged, relatively healthy community-based sample, key indices of subclinical cardiac remodeling were associated with higher or lower circulating concentrations of prohypertrophic and antihypertrophic adipokines in a context-specific manner. These observations may offer insights into the pathogenesis of the cardiomyopathy of obesity.

Postoperative Adverse Cardiovascular Events Associated with Leptin and Adverse Age After Elective Major Non-Cardiac Surgery: An Asian Single-Center Study

BACKGROUND The postoperative adverse cardiovascular events (PACE) after surgery can result in prolonged length of stay and poorer prognosis. The purpose of this Asian single-center study was to investigate the potential predicative role of leptin for PACE in elderly patients undergoing major non-cardiac surgery. MATERIAL AND METHODS The patients in the study were prospectively recruited from a series of elderly patients (≥60 years) undergoing elective major non-cardiac surgery (≥2 hours) in our hospital from June 2013 to June, 2016. The demographic and clinical data and the preoperative serum biomarkers of each participant were recorded in details. Suspected PACE were assessed by the same experienced expert based on clinical, blood, and other accessory tests. The univariate and multiple logistic regression analyses were plotted to evaluate the potential independent predictive factors for PACE. RESULTS A total of 270 elderly patients (145 males and 125 females), undergoing major elective non-cardiac surgery, were finally enrolled in this study. Older age, higher revised cardiac risk index score, higher levels of systolic blood pressure, B-type natriuretic peptide and leptin, the preoperative medication of beta blocker and lipid-lowering agents were positive predictors of PACE by univariate analyses (p<0.05). Our results indicated that preoperative leptin level (OR 1.84, 95% CI 1.08-3.42; p=0.015) and advanced age (OR 0.24, 95% CI 0.09-0.94; p=0.041) were significantly associated with the occurrence of PACE by multiple logistic regression analyses. CONCLUSIONS Preoperative serum leptin level and advanced age were two independent risk factors for PACE among elderly patients undergoing elective major non-cardiac surgery.

Cardio-renal Correlations and Epicardial Adipose Tissue in Patients with Type 2 Diabetes

Aim: The aim of the study was to evaluate the correlation between renal function and heart function/echocardiographic parameters and epicardial adipose tissue thickness (EATT), respectively.

Material and methods: Fifty patients with type 2 diabetes (T2D) were included in this study. Several laboratory parameters were obtained (HbA1c, fasting blood glucose, LDL-cholesterol, creatinine) and eGFR was calculated. Anthropometric measurements were performed (weight, waist and hip circumferences, 4 skinfolds, based on which % body fat was calculated). Patients underwent echocardiographic assessment to evaluate structural and functional parameters, including EATT. Left ventricular mass (LVM) was calculated and the geometric changes of the left ventricle were evaluated.

Results: Forty-six per cent of the patients had a LV ejection fraction (EF) <55% and 34% had diastolic dysfunction. There were no significant differences between the three eGFR groups with regards to metabolic parameters, but LVEF was lower (53.0 ± 0.8%, 54.4 ± 2.4%, and 55.2 ± 1.5%, respectively) and EATT was higher (11.0 ± 1.0 mm, 8.58 ± 2.2 mm, and 7.63 ± 2.6 mm, respectively) with a lower eGFR (p = 0.04). More patients with eGFR <90 mL/min/1.73 m2 had cardiac hypertrophy compared with those with eGFR ≥90 mL/min/1.73 m2 (p = 0.04). EATT correlated positively with several anthropometric parameters, e.g. weight (r = 0.309, 95% CI: 0.022 to 0.549, p = 0.03), BMI (r = 0.398, 95% CI: 0.123 to 0.616, p = 0.004), and negatively with LVEF (r = −0.496, 95% CI: −0.687 to −0.242, p = 0.0003) and eGFR (r = −0.293, 95% CI: −0.531 to −0.013, p = 0.04). In patients with LVEF <55% vs. ≥55%, the EATT was significantly higher (9.5 ± 1.99 mm vs. 7.33 ± 2.37 mm, p = 0.013).

Conclusion: In patients with T2D decreased renal function was associated with lower LVEF and higher EATT. EATT was also higher in patients with reduced LVEF.

Plasma leptin, but not resistin, TNF-α and adiponectin, is associated with echocardiographic parameters of cardiac remodeling in patients with coronary artery disease

The aim of this research was to assess the relationship between plasma adiponectin, leptin, resistin, tumor necrosis factor alpha (TNF-α) levels and echocardiographic parameters of ventricular remodeling in patients with coronary artery disease, without acute myocardial infarction. The study population consisted of 49 patients with echocardiographic measurements performed. After adjustment for age, gender, body mass index, systolic and diastolic blood pressure, and glycaemia, adiponectin was statistically significant associated with interventricular septum thickness (β = -0.304), left ventricular posterior wall thickness (β = -0.402), left ventricular end diastolic diameter (LVEDD; β = 0.385) and left ventricular relative wall thickness (β = -0.448, p < .05 for all). The associations were no longer significant when only patients without diabetes were included in the analysis. Leptin was associated with LVEDD (β = -0.354) and left ventricular relative wall thickness (β = 0.385, p < .05 for all). No associations between resistin, TNF-α and echocardiographic left ventricular parameters assessed were found in these patients. In conclusion, in patients with coronary artery disease and without acute myocardial infarction leptin may represent a potential mechanism of adverse cardiac remodeling. Resistin and TNF-α might not be involved in ventricular remodeling in these patients.

Leptin, An Adipokine With Central Importance in the Global Obesity Problem

Leptin has central importance in the global obesity and cardiovascular disease problem. Leptin is principally secreted by adipocytes and acts in the hypothalamus to suppress appetite and food intake, increase energy expenditure, and regulate body weight. Based on clinical translation of specific and networked actions, leptin affects the cardiovascular system and may be a marker and driver of cardiometabolic risk factors with interventions that are actionable by cardiologists. Leptin subnetwork analysis demonstrates a statistically significant role for ethnoculturally and socioeconomically appropriate lifestyle intervention in cardiovascular disease. Emergent mechanistic components and potential diagnostic or therapeutic targets include hexokinase 3, urocortins, clusterin, sialic acid-binding immunoglobulin-like lectin 6, C-reactive protein, platelet glycoprotein VI, albumin, pentraxin 3, ghrelin, obestatin prepropeptide, leptin receptor, neuropeptide Y, and corticotropin-releasing factor receptor 1. Emergent associated symptoms include weight change, eating disorders, vascular necrosis, chronic fatigue, and chest pain. Leptin-targeted therapies are reported for lipodystrophy and leptin deficiency, but they are investigational for leptin resistance, obesity, and other chronic diseases.

Severe degenerative aortic stenosis with preserved ejection fraction does not change adipokines serum levels

BACKGROUND

The role of the adipokines in the pathogenesis of aortic stenosis (AS) is not well established. The aim was to evaluate the relationship between adipokines and clinical characteristics as well as echocardiographic indices and noninvasive markers of vascular remodeling in patients with severe AS with preserved ejection fraction (EF).

METHODS

Sixty-five patients (F/M: 38/27; age: 68.3 ± 9.0 years; body mass index [BMI]: 29.6 ± 4.3 kg/m2) with severe AS with preserved EF: 33 patients with paradoxical low-flow low-gradient AS (PLFLG AS) and 32 patients with normal flow high-gradient AS (NFHG AS) were prospectively enrolled into the study. Twenty-four subjects (F/M: 14/10; age: 65.4 ± 8.7 years; BMI: 29.6 ± 4.3 kg/m2) who matched as to age, sex, BMI and coronary artery disease (CAD) constituted the control group (CG). Clinical data and markers of vascular remodeling were related to the serum adipokines.

RESULTS

There were no differences in the adipokines concentrations in the AS/CG. Patients with AS and coexisting CAD were characterized by decreased serum adiponectin (9.9 ± 5.5 vs. 12.7 ± 5.8 μg/mL, p = 0.040) and leptin (8.3 ± 7.8 vs. 21.6 ± 17.1 ng/mL, p < 0.001) levels compared to subjects without CAD. There were no differences in the serum adipokines concentrations between patients with PLFLG AS and NFHG AS. Systemic hypertension, diabetes, hyperlipidemia or markers of vascular remodeling did not discriminate adipokines concentrations. Multivariate regression analysis indicated that age (F = 3.02; p = 0.015) and E/E' index (F = 0.87, p = 0.032) were independent predictors of the adiponectin level in the AS group.

CONCLUSIONS

The presence of AS with preserved EF did not change the adipokine serum profile. Adipokines levels were modified by coexisting atherosclerosis but not the typical cardiovascular risk factors or the hemodynamic type of AS.

Leptin predicts short-term major adverse cardiac events in patients with coronary artery disease

INTRODUCTION

Leptin is an adipose tissue-derived hormone associated with cardiovascular risk factors. We examined whether leptin predicts major adverse cardiac events (MACE) in coronary artery disease (CAD) patients.

METHODS

Fasting plasma leptin levels were measured in 1327 male and 619 female CAD patients. The patients were followed up for two years. The primary endpoint (MACE) was the composite of a hospitalisation for congestive heart failure (CHF) or a cardiac death. The secondary endpoint was the composite of an acute coronary syndrome (ACS) or a stroke.

RESULTS

In regression analysis including established risk variables, high leptin levels were associated with a significantly increased risk of MACE (HR 3.37; 95%CI 1.64-6.90; p = 0.001) and ACS or stroke (HR 1.95; 95%CI 1.29-2.96; p = 0.002). Adding leptin to the risk model for MACE increased the C-index from 0.78 (95%CI 0.71-0.85) to 0.81 (0.74-0.88) and improved classification (NRI 0.36; 95%CI 0.13-0.60; p = 0.002) and discrimination of the patients (IDI 0.016; 95%CI 0.001-0.030; p = 0.031).

CONCLUSIONS

High plasma leptin levels predict short-term occurrence of CHF or cardiac death and ACS or stroke in patients with CAD independently of established risk factors. The possible harmful effects of leptin should be thoroughly investigated. Key messages Leptin is a peptide hormone secreted mainly by adipose tissue. It has been associated with several cardiovascular risk factors. High leptin levels predict the short-term occurrence of congestive heart failure or cardiac death and ACS or stroke in patients with CAD independently of established risk factors. The possible detrimental effects of leptin on the cardiovascular system should be thoroughly investigated.

Treatment with 17β-Estradiol Reduced Body Weight and the Risk of Cardiovascular Disease in a High-Fat Diet-Induced Animal Model of Obesity

Estrogen receptor α (ERα) and estrogen receptor β (ERβ) play important roles in cardiovascular disease (CVD) prevention. Recently, these estrogen receptors were reconsidered as an important treatment target of obesity leading to CVD. In this study, 17β-estradiol (17β-E) replacement therapy applied to high-fat diet-induced obese C57B male mice and ovariectomized (OVX) rats were evaluated, and the protective effects against high-fat diet-induced obesity were assessed in C57B mouse hearts. The results showed that 17β-E treatment activated both ERα and ERβ, and ERβ levels increased in a dose-dependent manner in high-fat diet C57B mouse cardiomyocytes following 17β-E treatment. Notably, an almost 16% reduction in body weight was observed in the 17β-E-treated (12 μg/kg/day for 60 days) high-fat diet-induced obese C57B male mice. These results suggested that 17β-E supplements may reduce CVD risk due to obesity.