Pericardial- Rather than Intramyocardial Fat Is Independently Associated with Left Ventricular Systolic Heart Function in Metabolically Healthy Humans

Linking abnormal fat distribution with HFpEF and diastolic dysfunction: a systematic review, meta-analysis, and meta-regression of observational studies

BACKGROUND

The global prevalence of obesity has escalated into a formidable health challenge intricately linked with the risk of developing cardiac diastolic disfunction and heart failure with preserved ejection fraction (HFpEF). Abnormal fat distribution is potentially strongly associated with an increased risk of cardiac diastolic dysfunction, and we aimed to scrutinize and elucidate the correlation between them.

METHODS

Following the Cochrane Handbook and PRISMA 2020 guidelines, we systematically reviewed the literature from PubMed, Embase, and Web of Science. We focused on studies reporting the mean and standard deviation (SD) of abnormal fat in HFpEF or cardiac diastolic dysfunction patients and the Pearson/Spearman correlation coefficients for the relationship between abnormal fat distribution and the risk of developing cardiac diastolic dysfunction. Data were standardized to the standard mean difference (SMD) and Fisher's z value for meta-analysis.

RESULTS

After progressive filtering and selection, 63 studies (43,113 participants) were included in the quantitative analyses. Abnormal fat distribution was significantly greater in participants with cardiac diastolic dysfunction than in controls [SMD 0.88 (0.69, 1.08)], especially in epicardial adipose tissue [SMD 0.99 (0.73, 1.25)]. Abnormal fat distribution was significantly correlated with the risk of developing cardiac diastolic dysfunction [E/E': 0.23 (0.18, 0.27), global longitudinal strain: r=-0.11 (-0.24, 0.02)]. Meta-regression revealed sample size as a potential heterogeneous source, and subgroup analyses revealed a stronger association between abnormal fat distribution and the risk of developing cardiac diastolic dysfunction in the overweight and obese population.

CONCLUSION

Abnormal fat distribution was significantly associated with the risk of developing cardiac diastolic dysfunction.

TRIAL REGISTRATION

CRD42024543774.

Ectopic lipid metabolism in anterior pituitary dysfunction

Over the past decades, adapted lifestyle and dietary habits in industrialized countries have led to a progress of obesity and associated metabolic disorders. Concomitant insulin resistance and derangements in lipid metabolism foster the deposition of excess lipids in organs and tissues with limited capacity of physiologic lipid storage. In organs pivotal for systemic metabolic homeostasis, this ectopic lipid content disturbs metabolic action, thereby promotes the progression of metabolic disease, and inherits a risk for cardiometabolic complications. Pituitary hormone syndromes are commonly associated with metabolic diseases. However, the impact on subcutaneous, visceral, and ectopic fat stores between disorders and their underlying hormonal axes is rather different, and the underlying pathophysiological pathways remain largely unknown. Pituitary disorders might influence ectopic lipid deposition indirectly by modulating lipid metabolism and insulin sensitivity, but also directly by organ specific hormonal effects on energy metabolism. In this review, we aim to I) provide information about the impact of pituitary disorders on ectopic fat stores, II) and to present up-to-date knowledge on potential pathophysiological mechanisms of hormone action in ectopic lipid metabolism.

Epicardial and Pericardial Adiposity Without Myocardial Steatosis in Cushing Syndrome

CONTEXT

Cardiovascular disease is the leading cause of death in patients with Cushing syndrome. Cortisol excess and adverse metabolic profile could increase cardiac fat, which can subsequently impair cardiac structure and function.

OBJECTIVE

We aimed to evaluate cardiac fat mass and distribution in patients with Cushing syndrome.

METHODS

In this prospective, cross-sectional study, 23 patients with Cushing syndrome and 27 control individuals of comparable age, sex, and body mass index were investigated by cardiac magnetic resonance imaging and proton spectroscopy. Patients were explored before and after biochemical disease remission. Myocardial fat measured by the Dixon method was the main outcome measure. The intramyocardial triglyceride/water ratio measured by spectroscopy and epicardial and pericardial fat volumes were secondary outcome measures.

RESULTS

No difference was found between patients and controls in intramyocardial lipid content. Epicardial fat mass was increased in patients compared to controls (30.8 g/m2 [20.4-34.8] vs 17.2 g/m2 [13.1-23.5], P < .001). Similarly, pericardial fat mass was increased in patients compared to controls (28.3 g/m2 [17.9-38.0] vs 11.4 g/m2 [7.5-19.4], P = .003). Sex, glycated hemoglobin A1c, and the presence of hypercortisolism were independent determinants of epicardial fat. Pericardial fat was associated with sex, impaired glucose homeostasis and left ventricular wall thickness. Disease remission decreased epicardial fat mass without affecting pericardial fat.

CONCLUSION

Intramyocardial fat stores are not increased in patients with Cushing syndrome, despite highly prevalent metabolic syndrome, suggesting increased cortisol-mediated lipid consumption. Cushing syndrome is associated with marked accumulation of epicardial and pericardial fat. Epicardial adiposity may exert paracrine proinflammatory effects promoting cardiomyopathy.

A Left Atrial Thrombus Mimic: Value of Ultrasound Enhancing Agents during Transesophageal Echocardiography

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Fat in the transverse pericardial sinus can mimic thrombus on TEE.

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Epicardial fat is more common in patients with AF.

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UEAs can differentiate extracardiac from intracardiac structures.

Plasma renin levels are associated with cardiac function in primary adrenal insufficiency

BACKGROUND

Despite adequate glucocorticoid (GC) and mineralocorticoid (MC) replacement therapy, primary adrenal insufficiency (AI) is associated with an increased mortality, mainly due to cardiovascular disease. The role of MC replacement is not known. Therefore, we assessed whether renin concentrations during routine GC and MC substitution therapy are associated with heart function and morphology.

METHODS

Thirty two patients with primary AI were included in a cross-sectional case-control study. In total, 17 patients and 34 healthy controls (age: 48 ± 12 vs. 46 ± 18 years; BMI: 23 ± 3 vs. 24 ± 3 kg/m2) underwent magnetic resonance spectroscopy and imaging measurements to assess cardiac function, morphology, ectopic lipids, and visceral/subcutaneous fat mass. Patients were divided according to their actual plasma renin concentration at the study visit (Actual-Reninlow vs. Actual-Reninhigh) and their median plasma renin concentration of previous visits (Median-Reninlow vs. Median-Reninhigh).

RESULTS

Ejection fraction was higher (67 ± 5 vs. 55 ± 3%; p = 0.001) and left ventricular mass was lower (60 ± 9 vs. 73 ± 10 g/m2; p = 0.025) in Actual-Reninhigh. Median-Reninhigh was associated with lower cardiac mass (64 ± 9 vs. 76 ± 11 g/m2; p = 0.029). Blood pressure, glucose, and lipid metabolism, as well as ectopic lipid content, pericardial fat mass, and visceral/subcutaneous fat were not different between the groups. Compared with controls, ejection fraction was significantly lower in patients with AI (56 ± 4 vs. 63 ± 8%; p = 0.019). No differences were found in patients with ≤20 mg compared with >20 mg of hydrocortisone per day.

CONCLUSIONS

Higher renin concentrations are associated with more favorable cardiac function and morphology in patients with primary AI.

Reduced hepatocellular lipid accumulation and energy metabolism in patients with long standing type 1 diabetes mellitus

The prevalence of obesity and metabolic syndrome increases in patients with type 1 diabetes mellitus (T1DM). In the general population this is linked with ectopic lipid accumulation in liver (HCL) and skeletal muscle (IMCL), representing hallmarks in the development of insulin resistance. Moreover, hepatic mitochondrial activity is lower in newly diagnosed patients with T1DM. If this precedes later development of diabetes related fatty liver disease is currently not known. This study aims to investigate energy metabolism in liver (k_ATP) and skeletal muscle (k_CK) and its impact on HCL, IMCL, cardiac fat depots and heart function in 10 patients with long standing T1DM compared to 11 well-matched controls by ³¹P/¹H magnetic resonance spectroscopy. HCL was almost 70% lower in T1DM compared to controls (6.9 ± 5% vs 2.1 ± 1.3%; p = 0.030). Also k_ATP was significantly reduced (0.33 ± 0.1 s^-1 vs 0.17 ± 0.1 s^-1; p = 0.018). In T1DM, dose of basal insulin strongly correlated with BMI (r = 0.676, p = 0.032) and HCL (r = 0.643, p = 0.045), but not with k_ATP. In the whole cohort, HCL was significantly associated with BMI (r = 0.615, p = 0.005). In skeletal muscle k_CK was lower in patients with T1DM (0.25 ± 0.05 s^-1 vs 0.31 ± 0-04 s^-1; p = 0.039). No significant differences were found in IMCL. Cardiac fat depots as well as heart function were not different. Our results in patients with long standing T1DM show that HCL is lower compared to matched controls, despite reduced energy metabolism in liver and skeletal muscle.

Characterization of different fat depots in NAFLD using inflammation-associated proteome, lipidome and metabolome

Non-alcoholic fatty liver disease (NAFLD) is recognized as a liver manifestation of metabolic syndrome, accompanied with excessive fat accumulation in the liver and other vital organs. Ectopic fat accumulation was previously associated with negative effects at the systemic and local level in the human body. Thus, we aimed to identify and assess the predictive capability of novel potential metabolic biomarkers for ectopic fat depots in non-diabetic men with NAFLD, using the inflammation-associated proteome, lipidome and metabolome. Myocardial and hepatic triglycerides were measured with magnetic spectroscopy while function of left ventricle, pericardial and epicardial fat, subcutaneous and visceral adipose tissue were measured with magnetic resonance imaging. Measured ectopic fat depots were profiled and predicted using a Random Forest algorithm, and by estimating the Area Under the Receiver Operating Characteristic curves. We have identified distinct metabolic signatures of fat depots in the liver (TAG50:1, glutamate, diSM18:0 and CE20:3), pericardium (N-palmitoyl-sphinganine, HGF, diSM18:0, glutamate, and TNFSF14), epicardium (sphingomyelin, CE20:3, PC38:3 and TNFSF14), and myocardium (CE20:3, LAPTGF-β1, glutamate and glucose). Our analyses highlighted non-invasive biomarkers that accurately predict ectopic fat depots, and reflect their distinct metabolic signatures in subjects with NAFLD.

Heart disease in chronic kidney disease – review of the mechanisms and the role of dialysis access

Cardiovascular complications are responsible not only for the high mortality, but also the morbidity of end-stage renal disease patients. Cyclic changes of fluid load, together with the altered metabolism, are responsible and are mirrored in many particular parts of the heart. A review of the mechanisms involved is presented and the role of dialysis access is highlighted.

Pericardial Fat Relates to Disturbances of Glucose Metabolism in Women with the Polycystic Ovary Syndrome, but Not in Healthy Control Subjects

OBJECTIVE

The objective of the present study is to investigate the relationship of cardiac fat depots with disturbances of the carbohydrate metabolism in women with PCOS.

METHODS

An oral glucose tolerance test (OGTT) was realized, and metabolic parameters were collected in 48 women with PCOS and in 20 controls. Intramyocardial fat (MYCL) and pericardial fat (PERI) were measured using ¹H-magnetic resonance spectroscopy and imaging.

RESULTS

Only in PCOS women, PERI was positively and independently related to parameters of glucose metabolism (HbA1c: p = 0.001, fasting plasma glucose: p < 0.001, stimulated glucose at 30 and 60 minutes in the OGTT). Thus, the disposition index, insulin sensitivity, and adiponectin also declined with the increase of PERI in women with PCOS; however, these results were not independent of BMI and age. In addition, PERI was positively related to atherogenic lipid profiles, BMI, waist circumference, CRP, and liver fat in women with PCOS. A negative relation of PERI with triglycerides and a positive relation with BMI and waist circumference could be observed in the controls. No relationship of MYCL with diabetes-specific parameters could be found in the study population.

CONCLUSION

PERI is related to metabolic disturbances in women with PCOS, but not in metabolically healthy lean subjects. This clinical trial was registered at ClinicalTrials.gov and has the registration number NCT03204461.

Role of Epicardial Adipose Tissue in Health and Disease: A Matter of Fat?

Epicardial adipose tissue (EAT) is a small but very biologically active ectopic fat depot that surrounds the heart. Given its rapid metabolism, thermogenic capacity, unique transcriptome, secretory profile, and simply measurability, epicardial fat has drawn increasing attention among researchers attempting to elucidate its putative role in health and cardiovascular diseases. The cellular crosstalk between epicardial adipocytes and cells of the vascular wall or myocytes is high and suggests a local role for this tissue. The balance between protective and proinflammatory/profibrotic cytokines, chemokines, and adipokines released by EAT seem to be a key element in atherogenesis and could represent a future therapeutic target. EAT amount has been found to predict clinical coronary outcomes. EAT can also modulate cardiac structure and function. Its amount has been associated with atrial fibrillation, coronary artery disease, and sleep apnea syndrome. Conversely, a beiging fat profile of EAT has been identified. In this review, we describe the current state of knowledge regarding the anatomy, physiology and pathophysiological role of EAT, and the factors more globally leading to ectopic fat development. We will also highlight the most recent findings on the origin of this ectopic tissue, and its association with cardiac diseases. © 2017 American Physiological Society. Compr Physiol 7:1051-1082, 2017.

Heart, lipids and hormones

Cardiovascular disease is the leading cause of death in general population. Besides well-known risk factors such as hypertension, impaired glucose tolerance and dyslipidemia, growing evidence suggests that hormonal changes in various endocrine diseases also impact the cardiac morphology and function. Recent studies highlight the importance of ectopic intracellular myocardial and pericardial lipid deposition, since even slight changes of these fat depots are associated with alterations in cardiac performance. In this review, we overview the effects of hormones, including insulin, thyroid hormones, growth hormone and cortisol, on heart function, focusing on their impact on myocardial lipid metabolism, cardiac substrate utilization and ectopic lipid deposition, in order to highlight the important role of even subtle hormonal changes for heart function in various endocrine and metabolic diseases.

The Flexibility of Ectopic Lipids

In addition to the subcutaneous and the visceral fat tissue, lipids can also be stored in non-adipose tissue such as in hepatocytes (intrahepatocellular lipids; IHCL), skeletal (intramyocellular lipids; IMCL) or cardiac muscle cells (intracardiomyocellular lipids; ICCL). Ectopic lipids are flexible fuel stores that can be depleted by physical exercise and repleted by diet. They are related to obesity and insulin resistance. Quantification of IMCL was initially performed invasively, using muscle biopsies with biochemical and/or histological analysis. ¹H-magnetic resonance spectroscopy (¹H-MRS) is now a validated method that allows for not only quantifying IMCL non-invasively and repeatedly, but also assessing IHCL and ICCL. This review summarizes the current available knowledge on the flexibility of ectopic lipids. The available evidence suggests a complex interplay between quantitative and qualitative diet, fat availability (fat mass), insulin action, and physical exercise, all important factors that influence the flexibility of ectopic lipids. Furthermore, the time frame of the intervention on these parameters (short-term vs. long-term) appears to be critical. Consequently, standardization of physical activity and diet are critical when assessing ectopic lipids in predefined clinical situations.