Epicardial Adipose Tissue, Adiponectin and Leptin: A Potential Source of Cardiovascular Risk in Chronic Kidney Disease

Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia

Cardiovascular function and adipose metabolism were markedly influenced under high altitudes. However, the interplay between adipokines and heart under hypoxia remains to be elucidated. We aim to explore alterations of adipokines and underlying mechanisms in regulating cardiac function under high altitudes. We investigated the cardiopulmonary function and five adipokines in Antarctic expeditioners at Kunlun Station (4,087 m) for 20 days and established rats exposed to hypobaric hypoxia (5,000 m), simulating Kunlun Station. Antarctic expeditioners exhibited elevated heart rate, blood pressure, systemic vascular resistance, and decreased cardiac pumping function. Plasma creatine phosphokinase-MB (CK-MB) and platelet-endothelial cell adhesion molecule-1 (sPecam-1) increased, and leptin, resistin, and lipocalin-2 decreased. Plasma leptin significantly correlated with altered cardiac function indicators. Additionally, hypoxic rats manifested impaired left ventricular systolic and diastolic function, elevated plasma CK-MB and sPecam-1, and decreased plasma leptin. Chronic hypoxia for 14 days led to increased myocyte hypertrophy, fibrosis, apoptosis, and mitochondrial dysfunction, coupled with reduced protein levels of leptin signaling pathways in myocardial tissues. Cardiac transcriptome analysis revealed leptin was associated with downregulated genes involved in rhythm, Na+/K+ transport, and cell skeleton. In conclusion, chronic hypoxia significantly reduced leptin signaling pathways in cardiac tissues along with significant pathological changes, thus highlighting the pivotal role of leptin in regulation of cardiac function under high altitudes.

[Morphofunctional Analysis of the Role of Epicardial Adipose Tissue in the Formation of the Obesity Paradox in Chronic Heart Failure]

Based on the available modern medical literature, the article summarizes data on the morpho-functional significance of epicardial adipose tissue (EAT) in health and heart failure, analyzes the likelihood and reliability of the formation of the obesity paradox, and also discusses its possible morpho-functional mechanisms. The authors reviewed and analyzed the consequences of the obesity paradox in the aspect of the normal EAT phenotype protectivity. The review proposed ways of further research in this direction aimed at a deep anatomical and physiological analysis and at determining the morpho-functional role of EAT in the adaptive mechanisms of myocardial trophic provision, which may be an important part of the pathogenetic connection between obesity and CHF and, therefore, can improve outcomes in such patients.

Effect of the interaction between the visceral-to-subcutaneous fat ratio and aldosterone on cardiac function in patients with primary aldosteronism

Primary aldosteronism is the most frequent secondary hypertensive disease and is characterized by an elevated risk for cardiovascular disease. The current standard treatments are adrenalectomy and/or administration of mineralocorticoid receptor blockers, both of which are effective at ameliorating hypertension via intervention for hyperaldosteronism. However, both of these approaches have side effects and contraindications, and mineralocorticoid receptor blockers also have limited preventive efficacy against cardiovascular events. Recently, in vitro experiments have shown that aldosterone regulation is closely related to abdominal fat accumulation and that there is crosstalk between aldosterone and visceral fat tissue accumulation. We previously reported that this interaction was clinically significant in renal dysfunction; however, its effects on the heart remain unclear. Here, we analyzed data from 49 patients with primary aldosteronism and 29 patients with essential hypertension to examine the potential effect of the interaction between the ratio of visceral-to-subcutaneous fat tissue volume and the plasma aldosterone concentration on echocardiographic indices, including the tissue Doppler-derived E/e' ratio. A significant interaction was found in patients with primary aldosteronism (p < 0.05), indicating that patients with the combination of a high plasma aldosterone concentration and high visceral-to-subcutaneous fat ratio show an increased E/e' ratio, which is a well-known risk factor for future cardiovascular events. Our results confirm the clinical importance of the interaction between aldosterone and abdominal fat tissue, suggesting that an improvement in the visceral-to-subcutaneous fat ratio may be synergistically and complementarily effective in reducing the elevated risk of cardiovascular disease in patients with primary aldosteronism when combined with conventional therapies for reducing aldosterone activity. A significant effect of the interaction between plasma aldosterone concentration and the visceral-to-subcutaneous fat ratio on the tissue Doppler-derived E/e' ratio in patients with primary aldosteronism.

The Relationship between Serum Adiponectin, Urinary Albumin/Creatinine Ratio and Type 2 Diabetes: A Population-Based Cross-Sectional Study

The relationship between serum adiponectin concentration (S-Adipo) and various diseases, such as type 2 diabetes (T2D) is conflicting. We hypothesized that the extent of kidney damage in patients with T2D may be responsible for this inconsistency and, thus, examined association between S-Adipo and T2D after consideration for the extent of kidney damage present. Of the 1816 participants in the population-based Iwaki study of Japanese people, 1751 participants with a complete dataset were included. Multivariate logistic regression analyses revealed that low S-Adipo was independently associated with T2D (<0.001), as was high urinary albumin to creatinine ratio (uACR) (<0.001). Principal components analysis showed that the relative value of S-Adipo to uACR (adiponectin relative excess) was significantly associated with T2D (odds ratio: 0.49, p < 0.001). Receiver operating curve analyses revealed that an index of adiponectin relative excess the ratio of S-Adipo to uACR was superior to S-Adipo per se as a marker of T2D (area under the curve: 0.746 vs. 0.579, p < 0.001). This finding indicates that the relationship between S-Adipo and T2D should be evaluated according to the extent of kidney damage present and may warrant similar analyses of the relationships between S-Adipo and other medicalconditions, such as cardiovascular disease.

In Silico Identification of Key Genes and Immune Infiltration Characteristics in Epicardial Adipose Tissue from Patients with Coronary Artery Disease

Background

The present study is aimed at identifying the differentially expressed genes (DEGs) and relevant biological processes and pathways associated with epicardial adipose tissue (EAT) from patients with coronary artery disease (CAD). We also explored potential biomarkers using two machine-learning algorithms and calculated the immune cell infiltration in EAT.

Materials and Methods

Three datasets (GSE120774, GSE64554, and GSE24425) were obtained from the Gene Expression Omnibus (GEO) database. The GSE120774 dataset was used to evaluate DEGs between EAT of CAD patients and the control group. Functional enrichment analyses were conducted to study associated biological functions and mechanisms using the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA). After this, the least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) were performed to identify the feature genes related to CAD. The expression level of the feature genes was validated in GSE64554 and GSE24425. Finally, we calculated the immune cell infiltration and evaluated the correlation between the feature genes and immune cells using CIBERSORT.

Results

We identified a total of 130 upregulated and 107 downregulated genes in GSE120774. Functional enrichment analysis revealed that DEGs are associated with several pathways, including the calcium signaling pathway, complement and coagulation cascades, ferroptosis, fluid shear stress and atherosclerosis, lipid and atherosclerosis, and regulation of lipolysis in adipocytes. TCF21, CDH19, XG, and NNAT were identified as feature genes and validated in the GSE64554 and GSE24425 datasets. Immune cell infiltration analysis showed plasma cells are significantly more numerous in EAT than in the control group (p = 0.001), whereas macrophage M0 (p = 0.024) and resting mast cells (p = 0.036) were significantly less numerous. TCF21, CDH19, XG, and NNAT were correlated with immune cells, including plasma cells, M0 macrophages, and resting mast cells.

Conclusion

TCF21, CDH19, XG, and NNAT might serve as feature genes for CAD, providing new insights for future research on the pathogenesis of cardiovascular diseases.

Fatty kidney: A possible future for chronic kidney disease research

BACKGROUND

Metabolic syndrome is a growing twenty-first century pandemic associated with multiple clinical comorbidities ranging from cardiovascular diseases, non-alcoholic fatty liver disease and polycystic ovary syndrome to kidney dysfunction. A novel area of research investigates the concept of fatty kidney in the pathogenesis of chronic kidney disease, especially in patients with diabetes mellitus or metabolic syndrome.

AIM

To review the most updated literature on fatty kidney and provide future research, diagnostic and therapeutic perspectives on a disease increasingly affecting the contemporary world.

MATERIALS AND METHOD

We performed an extensive literature search through three databases including Embase (Elsevier) and the Cochrane Central Register of Controlled Trials (Wiley) and PubMed/Medline Web of Science in November 2021 by using the following terms and their combinations: 'fatty kidney', 'ectopic fat', 'chronic kidney disease', 'cardiovascular event', 'cardio-metabolic risk', 'albuminuria' and 'metabolic syndrome'. Each study has been individually assessed by the authors.

RESULTS

Oxidative stress and inflammation, Klotho deficiency, endoplasmic reticulum stress, mitochondrial dysfunction and disruption of cellular energy balance appear to be the main pathophysiological mechanisms leading to tissue damage following fat accumulation. Despite the lack of large-scale comprehensive studies in this novel field of research, current clinical trials demonstrate fatty kidney as an independent risk factor for the development of chronic kidney disease and cardiovascular events.

CONCLUSION

The requirement for future studies investigating the pathophysiology, clinical outcomes and therapeutics of fatty kidney is clear.

Association of High Serum Adiponectin Level With Adverse Cardiovascular Outcomes and Progression of Coronary Artery Calcification in Patients With Pre-dialysis Chronic Kidney Disease

Background: Serum adiponectin level predicts cardiovascular (CV) outcomes and progression of coronary artery calcification (CAC) in the general population, although the association has not been validated in patients with chronic kidney disease (CKD). In this study, we investigated the association of high serum adiponectin level with the risk of adverse CV outcomes and progression of CAC in patients with pre-dialysis CKD.

Methods: A total of 1,127 patients with pre-dialysis CKD from a nationwide prospective cohort of patients with pre-dialysis CKD in Korea were divided into the tertile by serum adiponectin level at the baseline. CV outcome of interest was fatal and non-fatal CV events and all-cause mortality. Progression of CAC was defined as coronary artery calcium score (CACS) change more than 200 during a 4-year follow-up.

Results: Cox regression analysis revealed that high serum adiponectin is associated with increased risk of fatal and non-fatal CV events (adjusted hazard ratio 2.799, 95% CI 1.348–5.811). In contrast, high serum adiponectin level was not significantly associated with all-cause mortality (adjusted hazard ratio 0.655, 95% CI 0.203–2.113). Binary logistic regression analysis revealed that high serum adiponectin level is also associated with increased risk of progression of CAC (adjusted odds ratio [OR] 2.078, 95% CI 1.014–4.260). Subgroup analyses demonstrated that the association of high serum adiponectin with increased risk of fatal and non-fatal CV events is not modified by age, gender, history of diabetes, estimated glomerular filtration rate (eGFR), or spot urine albumin-to-creatinine ratio (ACR).

Conclusions: High serum adiponectin level is associated with adverse CV outcomes and progression of CAC in patients with pre-dialysis CKD.

Cardiorenal Fat: A Cardiovascular Risk Factor With Implications in Chronic Kidney Disease

There is a growing interest in the potential role of adipose tissues in cardiac and renal pathophysiology, and determining the mechanisms by which fat compartments around the heart and kidneys influence cardiovascular disease is of clinical importance in both general and high-risk populations. Epicardial fat and perirenal fat have been associated with adverse outcomes in chronic kidney disease (CKD) patients. Epicardial fat is a rich source of free fatty acids and is capable of secreting inflammatory and pro-atherogenic cytokines that promote atherosclerosis through a local paracrine effect. Recent evidence has demonstrated that perirenal fat has a closer correlation with kidney diseases than other visceral fat deposits in obesity or metabolic disturbances. Moreover, perirenal fat has been reported as an independent risk factor for CKD progression and even associated with cardiorenal dysfunction. Accordingly, these forms of organ-specific fat deposits may act as a connecter between vascular and cardiorenal disease. This review explores the possible links between epicardial and perirenal fat and its significant role as a modulator of cardiorenal dysfunction in CKD patients.

The Causes and Potential Injurious Effects of Elevated Serum Leptin Levels in Chronic Kidney Disease Patients

Leptin is an adipokine that regulates appetite and body mass and has many other pleiotropic functions, including regulating kidney function. Increased evidence shows that chronic kidney disease (CKD) is associated with hyperleptinemia, but the reasons for this phenomenon are not fully understood. In this review, we focused on potential causes of hyperleptinemia in patients with CKD and the effects of elevated serum leptin levels on patient kidney function and cardiovascular risk. The available data indicate that the increased concentration of leptin in the blood of CKD patients may result from both decreased leptin elimination from the circulation by the kidneys (due to renal dysfunction) and increased leptin production by the adipose tissue. The overproduction of leptin by the adipose tissue could result from: (a) hyperinsulinemia; (b) chronic inflammation; and (c) significant lipid disturbances in CKD patients. Elevated leptin in CKD patients may further deteriorate kidney function and lead to increased cardiovascular risk.

Age-specific waist circumference cutoff-points for abdominal obesity diagnosis: a personalized strategy for a large Venezuelan population

Background

Evidence shows that the ageing process is a determining factor in fat distribution, composition, and functionality. The goal of this research was to determine cut-off points for waist circumference according to age in the adult population from Maracaibo city, Venezuela.

Methodology

The Metabolic Syndrome Prevalence Study is a descriptive, cross-sectional study with multi-stage randomized sampling. In this post-hoc analysis 1902 individuals ≥18 years and from both sexes were evaluated. Waist circumference ROC curves were built for each age group and sex, using metabolic phenotypes for classification.

Results

52.2% (n = 992) were women, and the mean age was 38.7 ± 2. Cut-off points obtained for the <30 years age group were: 91 cm for women (Sensitivity: 96,8%, Specificity: 97,7%) and 94 cm for men (Sensitivity:100%, Specificity: 99,2%); for 30-49 years: women 94 cm (Sensitivity: 93.7%, Specificity: 97.1%) and men 95 cm (Sensitivity: 97.3%, Specificity: 100%); for ≥50 years: women 94 cm (Sensitivity: 91.8%, Specificity: 86.7%) and men 101 cm (Sensitivity: 100%, Specificity: 100%).

Conclusion

The use of specific cut-off points according to age groups is proposed to determine abdominal obesity in Maracaibo city due to the underestimation seen in young people and the overestimation observed in older people when using a unique cut-off point.

Association of the ratio of visceral-to-subcutaneous fat volume with renal function among patients with primary aldosteronism

Patients with primary aldosteronism have a higher risk of chronic kidney disease. Visceral fat tissue is hypothesized to stimulate the adrenal glands to overproduce aldosterone, and aldosterone promotes visceral fat tissue to produce inflammatory cytokines. However, it is unclear whether the volume of accumulated visceral fat tissue is associated with renal impairment among patients with hyperaldosteronism. We conducted a single-center cross-sectional study to assess the association between the estimated glomerular filtration rate and the ratio of the visceral-to-subcutaneous fat volume calculated by computed tomography. One hundred eighty patients with primary aldosteronism were enrolled. The mean ± SD age was 52.7 ± 11.0 years, and 60.0% were women. The ratio of visceral-to-subcutaneous fat volume was highly correlated with the estimated glomerular filtration rate (r = 0.49, p < 0.001). In multiple linear regression models, the ratio of visceral-to-subcutaneous fat tissue volume was significantly associated with the estimated glomerular filtration rate (estimates: -4.56 mL/min/1.73 m² per 1-SD), and there was an interaction effect between the plasma aldosterone concentration and the ratio of visceral-to-subcutaneous fat volume (p < 0.05). The group with a higher plasma aldosterone concentration exhibited a steeper decline in eGFR than the lower plasma aldosterone concentration group when the ratio increased. The ratio of visceral-to-subcutaneous fat tissue volume was an independent risk factor for renal dysfunction. This association increased in the presence of a high plasma aldosterone concentration. Clinicians should pay attention to the ratio of visceral-to-subcutaneous fat tissue volume and encourage primary aldosteronism patients to improve their lifestyle in addition to treating renin-aldosterone activity.

The effect of acute step-aerobic exercise on adiponectin and leptin levels in premenopausal women

BACKGROUND

It is well known that the prevalence of obesity, cardiovascular disease and metabolic syndrome is increasing during the transition to menopausal stages. The aim of this study was to investigate the effects of acute step-aerobic exercise on levels of leptin and adiponectin, which are adipose tissue-derived adipocytokines, associated with obesity, hypertension and other diseases in sedentary premenopausal women.

METHODS

Twenty-four sedentary premenopausal volunteer women between the ages of 40-45 (premenopause group) and 24 healthy adults between the ages of 21-39 (control group) were enrolled in this study. Moderate intensity step-aerobic exercise (50-60% of HR<inf>max</inf>) was applied for 60 min to the premenopausal subjects. Venous blood samples were obtained before and after the exercise. Adiponectin and leptin levels were determined using the ELISA method.

RESULTS

No statistically significant difference was found in terms of BMI values, and leptin levels between the premenopause and control group, while differences of adiponectin were statistically significant. Plasma leptin levels of the premenopausal women decreased whereas adiponectin levels increased meaningfully after the acute aerobic exercise (P<0.05). When the premenopausal women were grouped according to BMI, there were no significant differences between BMI≤30 and >30 groups in terms of leptin and adiponectin levels measured before and after exercise.

CONCLUSIONS

Our results may suggest that acute step aerobic exercise in premenopausal women alters leptin and adiponectin levels in favor of the organism. However, further studies are needed.

Assessment of arterial stiffness and epicardial adipose tissue thickness in predicting the subclinical atherosclerosis in patients with ankylosing spondylitis

OBJECTIVE

Atherosclerosis is a chronic, progressive, inflammatory disease. Recognition of subclinical atherosclerotic vascular changes before clinical manifestation in an asymptomatic population is important for risk stratification and optimal management, which finally leads to the prevention of cardiovascular disease. We aimed to determine the risk of premature subclinical atherosclerosis by evaluating epicardial adipose tissue thickness (EATT) and arterial stiffness parameters in patients with ankylosing spondylitis (AS).

METHODS

We performed a prospective study of 60 consecutive patients meeting modified New York criteria for AS compared to 60 controls matched for age and sex. Patients with traditional cardiovascular risk factors were excluded. Arterial stiffness parameters and EATT (examined via echocardiography) values of all patients and control groups were measured.

RESULTS

There was no difference between basal characteristic and echocardiographic parameters in patients with AS and in the control group. EATT and pulse wave velocity (PWV) were higher in the AS patients compared to the control group. EATT was 5.74 ± 1.22 mm and 4.91 ± 1.21 mm (p < .001) and PWV was 9.90 ± 0.98 m/s and 6.46 ± 0.83 m/s (p = .009) in the AS and control groups, respectively. Also, PWV was significantly correlated with EATT, age, and central blood pressure in patients with AS.

CONCLUSIONS

EATT and PWV, markers of atherosclerosis and cardiovascular disease, were significantly higher in patients with AS than the control group. In addition, in this study, it has been shown that there is a significant relationship between PWV and EATT in patients with AS.

ADIPOQ rs2241766 Gene Polymorphism and Predisposition to Diabetic Kidney Disease

BACKGROUND

This meta-analysis was performed to obtain a more comprehensive estimation of the role of the single nucleotide polymorphism (SNP) rs2241766 in the ADIPOQ gene in the occurrence of diabetic kidney disease (DKD).

METHODS

Relevant studies were identified from digital databases such as Embase, PubMed, Medline, Cochrane Library, Google Scholar, WanFang, and Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were pooled by means of fixed- or random-effects models. Interstudy heterogeneity was examined using the Q test and I ² statistic, and sensitivity analysis was implemented to test the statistical stability of the overall estimates. Begg's funnel plot and Egger's test were applied to inspect potential publication bias among the included studies.

RESULTS

The overall ORs reflected a positive correlation between the ADIPOQ rs2241766 polymorphism and susceptibility to DKD in the GG vs. TT and GG vs. TT+TG comparisons (OR = 1.51, 95%CI = 1.16 - 1.95; OR = 1.43, 95%CI = 1.11 - 1.85). After stratification analyses by ethnicity and disease type, a similar trend was also revealed in the Caucasian and African subgroups as well as in the type 2 diabetes mellitus (T2DM) subgroup.

CONCLUSION

The ADIPOQ rs2241766 polymorphism may be associated with an increased risk of DKD, especially in Caucasian and African populations as well as in T2DM patients.

Correlation Between Fecal Metabolomics and Gut Microbiota in Obesity and Polycystic Ovary Syndrome

Objective: This study aimed to explore the relationship between the fecal metabolites and gut microbiota in obese patients with PCOS and provide a new strategy to elucidate the pathological mechanism of obesity and PCOS. Methods: The fecal samples of obese patients with PCOS (n = 18) and obese women without PCOS (n = 15) were analyzed by 16S rRNA gene sequencing and untargeted metabolomics. The peripheral venous blood of all subjects was collected to detect serum sex hormones. The association among fecal metabolites, gut microbiota, and serum sex hormones was analyzed with the R language. Results: A total of 122 named differential fecal metabolites and 18 enrichment KEGG pathways were obtained between the groups. Seven fecal metabolites can be used as characteristic metabolites, including DHEA sulfate. The richness and diversity of gut microbiota in the obese PCOS group were lower than those in the control group. Lachnoclostridium, Fusobacterium, Coprococcus_2, and Tyzzerela 4 were the characteristic genera of the obese patients with PCOS. Serum T level significantly and positively correlated with the abundance of fecal DHEA sulfate (p < 0.05), and serum DHEAS level significantly and negatively correlated with the abundance of fecal teasterone (p < 0.05). Conclusion: Specific fecal metabolites may be used as characteristic metabolites for obese patients with PCOS. The closely relationship among gut microbiota, fecal metabolites, and serum sex hormones may play a role in the related changes caused by hyperandrogenemia.