Do cardiac and perivascular adipose tissue play a role in atherosclerosis?

Contributions of Noncardiac Organ-Heart Immune Crosstalk and Somatic Mosaicism to Heart Failure: Current Knowledge and Perspectives

Heart failure is the final outcome of most cardiovascular diseases and shares risk factors with other cardiovascular pathologies. Among these, inflammation plays a central role in disease progression and myocardial remodeling. Over the past 2 decades, numerous studies have explored immune-related mechanisms in cardiovascular disease, highlighting the importance of immune cross-talk between the heart and extra-cardiac organs, including bone marrow, spleen, liver, gut, and adipose tissue. This review examines how immune interactions among these organs contribute to heart failure pathogenesis, with a focus on clonal hematopoiesis, an age-related alteration of hematopoietic stem cells that fosters pathological bone marrow-heart communication. Additionally, we explore recent advances in the understanding of clonal hematopoiesis and its role in heart failure, emphasizing its implications for prognosis and potential therapeutic interventions. By integrating insights from immunology, metabolism, and aging, we provide a comprehensive perspective on the immunologic determinants of heart failure, paving the way for precision medicine approaches aimed at mitigating cardiovascular risk.

The relationship of redox signaling with the risk for atherosclerosis

Oxidative balance plays a pivotal role in physiological homeostasis, and many diseases, particularly age-related conditions, are closely associated with oxidative imbalance. While the strategic role of oxidative regulation in various diseases is well-established, the specific involvement of oxidative stress in atherosclerosis remains elusive. Atherosclerosis is a chronic inflammatory disorder characterized by plaque formation within the arteries. Alterations in the oxidative status of vascular tissues are linked to the onset, progression, and outcome of atherosclerosis. This review examines the role of redox signaling in atherosclerosis, including its impact on risk factors such as dyslipidemia, hyperglycemia, inflammation, and unhealthy lifestyle, along with dysregulation, vascular homeostasis, immune system interaction, and therapeutic considerations. Understanding redox signal transduction and the regulation of redox signaling will offer valuable insights into the pathogenesis of atherosclerosis and guide the development of novel therapeutic strategies.

Menopause transition and cardiovascular disease risk

The risk of cardiovascular disease (CVD) notably increases in the fifth decade of a woman's life, coinciding with the onset of menopause and occurring 10 years later than the similar age-related increase in men. Menopause marks a significant transition in a woman's life and is accompanied by cardiometabolic changes, including a shift in body composition, increased blood pressure, disruptions in lipoproteins, and insulin resistance. There is increasing evidence that the menopause transition is a risk factor for CVD, independent of age-related changes, especially considering that the earlier the onset of menopause, the greater is the CVD risk. Further, menopause-related symptoms such as vasomotor symptoms, sleep disturbances, and mood changes may all have a direct impact on CVD risk. In this review, we summarize the current literature regarding CVD in midlife women, focusing on the cardiometabolic changes related to ovarian aging versus chronological aging, as well as those related to specific menopause characteristics, including age, type of menopause and the use of menopause hormone therapy.

The menopausal transition period and cardiovascular risk

The menopausal transition period spans, on average, 2-8 years before the final menstrual period and is associated with an increase in clinical and subclinical cardiovascular risk. In this Review, we discuss the metabolic and cardiovascular changes that occur during the menopausal transition period and the role of ovarian ageing, chronological ageing and other ageing-related risk factors in mediating these changes. Disentangling the relative contributions of chronological and reproductive ageing to cardiovascular risk is challenging, but data from longitudinal studies in women transitioning from premenopause to post-menopause have provided valuable insights. We also discuss evidence on how cardiovascular risk is altered by premature or early menopause, surgical menopause, and vasomotor and other menopausal symptoms. Whether targeted interventions can slow the progression of atherosclerosis and subclinical disease during the menopausal transition, thus delaying or preventing the onset of cardiovascular events, remains to be determined. Furthermore, we consider the recommended strategies for cardiovascular risk reduction in women undergoing menopausal transition using the framework of the American Heart Association's Life's Essential 8 key measures for improving and maintaining cardiovascular health, and discuss the cardiovascular risks and benefits of menopausal hormone therapy. Finally, we also discuss novel therapies that might benefit this population in reducing cardiovascular risk.

The Role and Implications of Epicardial Fat in Coronary Atherosclerotic Disease

The current minireview aims to assess the implications of epicardial fat secretory function in the development of coronary artery disease. The epicardial adipose tissue (EAT) is a visceral fat depot that has been described as a cardiovascular risk factor. In addition to its mechanical protection role and physiological secretory function, it seems that various secretion products of the epicardial fat are responsible for metabolic disturbances at the level of the cardiac muscle when in association with pre-existing pathological conditions, such as metabolic syndrome. There is a pathological reduction in sarcomere shortening, abnormal cytosolic Ca²⁺ fluxes, reduced expression of sarcoplasmic endoplasmic reticulum ATPase 2a and decreased insulin-mediated Akt-Ser473-phosphorylation in association with abnormal levels of epicardial fat tissue. Activin A, angiopoietin-2, and CD14-positive monocytes selectively accumulate in the diseased myocardium, resulting in reduced cardiomyocyte contractile function. At the same time, it is believed that these alterations in secretory products directly decrease the myocyte function via molecular changes, thus contributing to the development of coronary disease when certain comorbidities are associated.

Relation of Menopause With Cardiovascular Risk Factors in South Asian American Women (from the MASALA Study)

The menopausal transition is a time of accelerating risk of cardiovascular disease (CVD), and promoting cardiovascular health during midlife is an important period of time to prevent CVD in women. The association of menopause with cardiovascular risk factors or subclinical atherosclerosis has not previously been evaluated in South Asian American women, a population with a disproportionately higher CVD burden compared with other race/ethnic groups. The objective of this study was to evaluate the association of menopause with CVD risk factors and subclinical cardiometabolic disease markers. We studied women aged 40 to 84 years from the Mediators of Atherosclerosis in South Asians Living in America study. The association of self-reported menopausal status with multiple demographic and clinical variables was assessed with linear and logistic regression adjusted for age and cardiovascular health behaviors. In a secondary ("age-restricted") analysis, postmenopausal participants outside the age range of premenopausal participants were excluded. In the age-restricted sample, menopause was associated with a higher adjusted odds of hypertension (odds ratio = 1.19, 95% confidence interval [CI] 1.02 to 1.41), and higher systolic blood pressure (β = 6.34, 95% CI 0.82 to 11.87), and significantly higher subcutaneous fat area (β = 42.8, 95% CI 5.8 to 91.4). No significant associations between menopause and ectopic fat deposition, coronary artery calcium, or carotid intima-media thickness were observed. In South Asian American women in the Mediators of Atherosclerosis in South Asians Living in America study, menopause was associated with cardiovascular risk factors and higher subcutaneous fat deposition. Menopausal status is an important factor to examine and address CVD risk factors.

Epicardial fat tissue can predict subclinical left ventricular dysfunction in patients with erectile dysfunction

BACKGROUND

Erectile dysfunction (ED) is an early form of atherosclerosis and subclinical myocardial dysfunction. Epicardial fat tissue (EFT) is associated with impaired left ventricular (LV) function, even in the absence of cardiovascular disease. The aim of this study was to investigate the association between EFT and LV systolic function in patients with erectile ED by speckle tracking echocardiography (2D-STE) method.

METHODS

A total of 129 consecutive patients with ED were compared with 145 age- and sex-matched control subjects. ED was evaluated using the International Index of Erectile Function questionnaire. Thickness of EFT was measured by TTE. Global LV longitudinal strain (LV-GLS) and global LV circumferential strain (LV-GCS) were measured by 2D-STE method.

RESULTS

The EFT thickness was significantly higher in the patients with ED (p <.01). LV-GLS and LV-GCS were revealed to be more deterioration in the ED group compared to controls (-18.2 ± 2.7 vs. (-21.1 ± 3.9, p<.001; -19.5 ± 4.1 vs. -21.9 ± 3.9, p<.001, respectively). It has been shown that EFT thickness is an independent predictor of LV dysfunction.

CONCLUSIONS

These results indicate that EFT thickness is associated with subclinical LV systolic dysfunction in patients with ED.

Heart fat and carotid artery atherosclerosis progression in recently menopausal women: impact of menopausal hormone therapy: The KEEPS trial

OBJECTIVE

Heart fat deposition has been linked to atherosclerosis, and both accelerate after menopause. Hormone therapy (HT) may differentially slow heart fat deposition and progression of atherosclerosis, depending on the specific HT agent or its route of administration. Our objective was to evaluate the effects of different HT agents, oral and transdermal, on associations between heart fat accumulation and atherosclerosis progression, measured by carotid intima-media thickness (CIMT), in recently menopausal women from the Kronos Early Estrogen Prevention Study (KEEPS) trial.

METHODS

KEEPS was a randomized, placebo-controlled trial of the effects of 0.45 mg/d oral conjugated equine estrogens (o-CEE) or 50 mcg/d transdermal 17β-estradiol (t-E2), compared with placebo, on 48 months progression of CIMT. Epicardial adipose tissue (EAT) and paracardial adipose tissue (PAT) volumes were quantified by computed tomography.

RESULTS

In all, 467 women (mean age [SD] 52.7 [2.5]; 78.2% White; 30% on o-CEE, 30.8% t-E2, 39.2% placebo) with heart fat volumes and CIMT at baseline and 48 months were included. EAT and PAT changes were not associated with CIMT progression; however, the assigned treatment significantly modified the association between PAT (but not EAT) change and CIMT progression. In the o-CEE group, adjusted CIMT progression was 12.66 μm (95% confidence interval [CI] 1.80, 23.52) lower than in t-E2 group (P = 0.02), and 10.09 μm (95% CI 0.79, 19.39) lower than in placebo group (P = 0.03), as per 1-SD increase in PAT.

CONCLUSION

Compared with t-E2, o-CEE appears to slow down the adverse effect of increasing PAT on progression of atherosclerosis. Whether this beneficial association is specific to CEE or to the oral route of CEE administration is unclear and should be assessed further.

Identification of Cardiovascular Risk Factors in Obese Adolescents With Metabolic Syndrome

Objective: There are studies that show different associations between metabolic syndrome (MS) and cardiovascular disease in adolescent. This study is aimed to identify probable cardio-vascular risk factors in obese adolescents with MS. Methods: Sixty-five obese adolescents with a body mass index (BMI) > 95 percentile were enrolled and divided into two groups with MS or without MS. Left ventricular mass (LVM), left ventricular mass index, ejection fraction, epicardial fat thickness, visceral fat thickness (VFT) and carotid intima-media thickness were measured. Anthropometric and blood chemistry parameters were estimated. Above parameters were compared based on presence or absence of MS. Results: The prevalence of MS was 23.1% in obese adolescents. LVM showed significant correlation with body mass index (BMI), hip circumference (HC), fat mass, total cholesterol (TC), LDL-cholesterol (LDL-C) and waist circumference (WC). VFT significantly correlated with WC, BMI, hip circumflex (HC), obesity index (OI), fat %, fat mass, insulin, TC, LDL-C, insulin, triglyceride (TG), glucose, homeostatic model assessment for insulin resistance (HOMA-IR) and leptin. Conclusions: Screening for the MS in overweight adolescents may help to predict risk of future cardiovascular disease. These data suggest that LVMI and VFT are significant parameters for predicting cardiovascular disease risk in obese adolescents.

Menopause Transition and Cardiovascular Disease Risk: Implications for Timing of Early Prevention: A Scientific Statement From the American Heart Association

Cardiovascular disease (CVD) is the leading cause of death in women, who have a notable increase in the risk for this disease after menopause and typically develop coronary heart disease several years later than men. This observation led to the hypothesis that the menopause transition (MT) contributes to the increase in coronary heart disease risk. Over the past 20 years, longitudinal studies of women traversing menopause have contributed significantly to our understanding of the relationship between the MT and CVD risk. By following women over this period, researchers have been able to disentangle chronological and ovarian aging with respect to CVD risk. These studies have documented distinct patterns of sex hormone changes, as well as adverse alterations in body composition, lipids and lipoproteins, and measures of vascular health over the MT, which can increase a woman's risk of developing CVD postmenopausally. The reported findings underline the significance of the MT as a time of accelerating CVD risk, thereby emphasizing the importance of monitoring women's health during midlife, a critical window for implementing early intervention strategies to reduce CVD risk. Notably, the 2011 American Heart Association guidelines for CVD prevention in women (the latest sex-specific guidelines to date) did not include information now available about the contribution of the MT to increased CVD in women. Therefore, there is a crucial need to discuss the contemporary literature on menopause and CVD risk with the intent of increasing awareness of the significant adverse cardiometabolic health-related changes accompanying midlife and the MT. This scientific statement provides an up-to-date synthesis of the existing data on the MT and how it relates to CVD.

Quantitative Imaging of Body Composition

Body composition refers to the amount and distribution of lean tissue, adipose tissue, and bone in the human body. Lean tissue primarily consists of skeletal muscle; adipose tissue comprises mostly abdominal visceral adipose tissue and abdominal and nonabdominal subcutaneous adipose tissue. Hepatocellular and myocellular lipids are also fat pools with important metabolic implications. Importantly, body composition reflects generalized processes such as increased adiposity in obesity and age-related loss of muscle mass known as sarcopenia.In recent years, body composition has been extensively studied quantitatively to predict overall health. Multiple imaging methods have allowed precise estimates of tissue types and provided insights showing the relationship of body composition to varied pathologic conditions. In this review article, we discuss different imaging methods used to quantify body composition and describe important anatomical locations where target tissues can be measured.

BMPER is upregulated in obesity and seems to have a role in pericardial adipose stem cells

Pericardial adipose tissue (PAT), a visceral fat depot enveloping the heart, is an active endocrine organ and a source of free fatty acids and inflammatory cytokines. As in other fat adult tissues, PAT contains a population of adipose stem cells; however, whether these cells and/or their environment play a role in physiopathology is unknown. We analyzed several stem cell-related properties of pericardial adipose stem cells (PSCs) isolated from obese and ex-obese mice. We also performed RNA-sequencing to profile the transcriptional landscape of PSCs isolated from the different diet regimens. Finally, we tested whether these alterations impacted on the properties of cardiac mesoangioblasts isolated from the same mice. We found functional differences between PSCs depending on their source: specifically, PSCs from obese PSC (oPSC) and ex-obese PSC (dPSC) mice showed alterations in apoptosis and migratory capacity when compared with lean, control PSCs, with increased apoptosis in oPSCs and blunted migratory capacity in oPSCs and dPSCs. This was accompanied by different gene expression profiles across the cell types, where we identified some genes altered in obese conditions, such as BMP endothelial cell precursor-derived regulator (BMPER), an important regulator of BMP-related signaling pathways for endothelial cell function. The importance of BMPER in PSCs was confirmed by loss- and gain-of-function studies. Finally, we found an altered production of BMPER and some important chemokines in cardiac mesoangioblasts in obese conditions. Our findings point to BMPER as a potential new regulator of PSC function and suggest that its dysregulation could be associated with obesity and may impact on cardiac cells.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

Increased inflammation, oxidative stress and a reduction in antioxidant defense enzymes in perivascular adipose tissue contribute to vascular dysfunction in type 2 diabetes

BACKGROUND

Perivascular adipose tissue (PVAT) surrounds most large blood vessels and plays an important role in vascular homeostasis. The present study was conducted to investigate the contribution of PVAT to vascular dysfunction in a rat model of type 2 diabetes.

MATERIAL AND METHODS

Several in vivo parameters such as lipid profile (total cholesterol and triglyceride systemic levels), fasting glucose levels, glucose tolerance and insulin sensitivity (through glucose and insulin tolerance tests, respectively) were determined in Goto-Kakizaki (GK) diabetic rats and compared with control Wistar rats. At the vascular level, endothelial dependent and independent relaxation and contraction studies were performed in aortic rings in the absence (PVAT-) or in the presence (PVAT+) of thoracic PVAT. We also evaluated vascular oxidative stress and performed western blots, PCR and immunohistochemistry analysis of cytokines and various enzymes in PVAT.

RESULTS

Endothelium-dependent relaxation to acetylcholine, assessed by wire myography, was impaired in GK rats and improved by the antioxidant TEMPOL and by the TLR4 inhibitor, CLI-095 suggesting an increase in oxidative stress and inflammation. In addition, vascular superoxide and peroxynitrite production was increased in the vascular wall of diabetic rats, accompanied by reduced nitric oxide bioavailability. The presence of PVAT had an anticontractile effect in response to phenylephrine in Wistar rats that was lost in GK rats. Western blot and immunohistochemistry analysis revealed that PVAT phenotype shifts, under diabetic conditions, towards a proinflammatory (with increment in CRP, CCL2, CD36), pro-oxidant (increased levels of aldose reductase, and reduced levels of antioxidant deference enzymes) and vasoconstriction state.

CONCLUSION

Our data suggest that this rat model of type 2 diabetes is associated with perivascular adipose dysfunction that contributes to oxidative stress, inflammation and endothelial dysfunction.

Epicardial Adipose Tissue: Clinical Biomarker of Cardio-Metabolic Risk

Epicardial adipose tissue (EAT) is part of the visceral adipose tissue (VAT) that surrounds the heart and it is a quantifiable, modifiable, and multifaceted tissue that has both local and systemic effects. When EAT is enlarged, EAT contributes to atherosclerotic cardiovascular disease (ASCVD) risk and plays a role in the development of metabolic syndrome (MetS). In this review, we will discuss the role of EAT in various facets of MetS, including type 2 diabetes mellitus (T2DM) and insulin resistance. We examine the association between EAT and liver steatosis. We also address the correlations of EAT with HIV therapy and with psoriasis. We discuss racial differences in baseline EAT thickness. We conclude that EAT measurement serves as a powerful potential diagnostic tool in assessing cardiovascular and metabolic risk. Measurement of EAT is made less costly, more convenient, and yet accurate and reliable by transthoracic echocardiography. Furthermore, modification of EAT thickness has therapeutic implications for ASCVD, T2DM, and MetS.

The menopause transition and women's health at midlife: a progress report from the Study of Women's Health Across the Nation (SWAN)

OBJECTIVE

Our initial understanding of the menopause transition (MT) has been framed by clinical samples of women seeking treatment rather than by population-based studies. The Study of Women's Health Across the Nation (SWAN) initiated in 1996 with an overall goal to define the MT, to characterize its biological and psychosocial antecedents and sequelae in an ethnically and racially diverse sample of midlife women.

METHODS

This review summarizes the central findings of SWAN to date that can inform women and their healthcare providers about the impact of the MT and midlife aging on overall health and well-being.

RESULTS

SWAN characterized changes in reproductive axis and menstrual cycle patterns that informed the development of the reproductive aging staging system Staging of Reproductive Aging Workshop+10; MT-related symptoms and mental health (vasomotor symptoms, sleep complaints, psychological symptoms, cognitive performance, and urogenital and sexual health); and physiological systems and functions (cardiovascular and cardiometabolic health, bone health, physical function performance) that are influenced by the MT. SWAN demonstrated substantial interrelations among these changes and significant racial/ethnic differences in the rate and magnitude of change in multiple health indictors in midlife women. The findings point to midlife as a critical stage for adopting healthy behavior and preventive strategies.

CONCLUSIONS

Over the past 23 years, SWAN has advanced our understanding of the impact of the MT and midlife aging on health and well-being in women. SWAN will be instrumental to determine whether MT-related changes during midlife are related to unfavorable health and well-being in early old age.

Effects of Hormone Therapy on Heart Fat and Coronary Artery Calcification Progression: Secondary Analysis From the KEEPS Trial

Background Heart fats (epicardial and paracardial adipose tissue [PAT]) are greater after menopause. Endogenous estrogen may regulate these fat depots. We evaluated the differential effects of hormone therapy formulations on heart fat accumulations and their associations with coronary artery calcification (CAC) progression in recently menopausal women from KEEPS (Kronos Early Estrogen Prevention Study). Methods and Results KEEPS was a multicenter, randomized, placebo-controlled trial of the effects of 0.45 mg/d oral conjugated equine estrogens and 50 µg/d transdermal 17β-estradiol, compared with placebo, on 48-month progression of subclinical atherosclerosis among 727 early menopausal women. CAC progression was defined if baseline CAC score was 0 and 48-month CAC score was >0 or if baseline CAC score was >0 and <100 and annualized change in CAC score was ≥10. Of 727 KEEPS participants, 474 (mean age: 52.7 [SD: 2.6]; 78.1% white) had computed tomography-based heart fat and CAC measures at both baseline and 48 months. Compared with women on placebo, women on oral conjugated equine estrogens were less likely to have any increase in epicardial adipose tissue (odds ratio for oral conjugated equine estrogens versus placebo: 0.62 [95% CI, 0.40-0.97]; P=0.03). PAT did not change in any group. Changes in epicardial adipose tissue and PAT did not differ by treatment group. CAC increased in 14% of participants. The assigned treatment modified the association between PAT changes and CAC progression (P=0.02) such that PAT increases were associated with CAC increases only in the transdermal 17β-estradiol group. Conclusions In recently menopausal women, oral conjugated equine estrogens may slow epicardial adipose tissue accumulation, whereas transdermal 17β-estradiol may increase progression of CAC associated with PAT accumulation. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00154180.

Presence of fragmented QRS is associated with increased epicardial adipose tissue thickness in hypertensive patients

BACKGROUND

Epicardial adipose tissue (EAT) is a cardiometabolic risk factor, and its possible relationship with hypertension has been reported previously. Fragmented QRS (fQRS) detected on electrocardiography (ECG) has been demonstrated to be a marker of myocardial fibrosis. In this study, we aimed to investigate the relationship between the thickness of EAT, and presence of fQRS in hypertensive patients.

METHODS

Consecutive patients who were diagnosed with hypertension were included in the study. ECG and transthoracic echocardiography (TTE) were performed to all patients. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. Thickness of EAT was measured by TTE.

RESULTS

This study enrolled 69 hypertensive patients with fQRS on ECG and 45 hypertensive patients without fQRS as the control group. Age (P = .869), and gender distribution (P = .751) were similar in both groups. Left atrial diameter (P = .012), interventricular septal thickness (P < .001), posterior wall thickness (P < .001), left ventricular ejection fraction (P = .009), left ventricular mass (P = .006), left ventricular mass ındex (P = .014), left ventricular hypertrophy (P = .003), and EAT thickness (P < .001) were found to be significantly increased in patients with fQRS. In multivariate analysis, among these variables only EAT was observed to be an independent predictor of fQRS (odds ratio:3.306 [95% confidence interval, 0.030-0.118], P = .001).

CONCLUSION

A significant association exists between the presence of fQRS and EAT thickness in hypertensive patients. The presence of fQRS, just as EAT thickness, may be used as a cardiometabolic risk factor in hypertensive patients.

Epicardial Adipose Tissue and Renal Disease

Epicardial adipose tissue (EAT) is derived from splanchnic mesoderm, localized anatomically between the myocardium and pericardial visceral layer, and surrounds the coronary arteries. Being a metabolically active organ, EAT secretes numerous cytokines, which moderate cardiovascular morphology and function. Through its paracrine and vasocrine secretions, EAT may play a prominent role in modulating cardiac function. EAT protects the heart in normal physiological conditions by secreting a variety of adipokines with anti-atherosclerotic properties, and in contrast, secretes inflammatory molecules in pathologic conditions that may play a dynamic role in the pathogenesis of cardiovascular diseases by promoting atherosclerosis. Considerable research has been focused on comparing the anatomical and biochemical features of EAT in healthy people, and a variety of disease conditions such as cardiovascular diseases and renal diseases. The global cardiovascular morbidity and mortality in renal disease are high, and there is a paucity of concrete evidence and societal guidelines to detect early cardiovascular disease (CVD) in this group of patients. Here we performed a clinical review on the existing evidence and knowledge on EAT in patients with renal disease, to evaluate its application as a reliable, early, noninvasive biomarker and indicator for CVD, and to assess its significance in cardiovascular risk stratification.

Cardiovascular Implications of the Menopause Transition: Endogenous Sex Hormones and Vasomotor Symptoms

The menopause transition (MT) is a critical period of women's lives marked by several physiologic changes and menopause-related symptoms that have implications for health. Risk for cardiovascular disease, the leading cause of death in women, increases after menopause, suggesting a contribution of the MT to its development. This article focuses on the relationship between 2 main features of the MT and women's cardiovascular health: (1) dynamic alterations of sex hormones, particularly endogenous estradiol and follicle-stimulating hormone, and (2) vasomotor symptoms, the cardinal symptom of the menopause. Limitations and future directions are discussed.

Association of Cardiovascular Health with Epicardial Adipose Tissue and Intima Media Thickness: The Kardiovize Study

Background: Intima-media thickness (IMT) has been proposed as a measurement of subclinical atherosclerosis and has been associated with cardiovascular disease (CVD). Epicardial adipose tissue (EAT) is a fat depot between the pericardium and myocardium and has been associated with coronary atherosclerosis. The relationship between IMT and EAT thickness has not been reported before. We investigated the relationship between EAT thickness, IMT, CVD risk factors, and ideal cardiovascular health (CVH) metrics using subjects from the Kardiovize Brno 2030 cohort study, a random urban sample population in Central Europe. Methods: We studied 102 individuals (65 males) aged 25–64 years (median = 37 years) with no current or past CVD history. We measured IMT using a vascular ultrasound and EAT thickness using transthoracic echocardiography, and collected data on anthropometric factors, CVD risk factors, and CVH score. Correlation tests and multiple linear regression models were applied. Results: In the age- and gender-adjusted model, we demonstrated that, among CVD risk factors, only BMI was significantly and positively associated with EAT thickness (β = 0.182, SE = 0.082, p = 0.030), while no significant associations with IMT were evident. Although both EAT thickness and IMT were negatively correlated with CVH score (r = −0.45, p < 0.001, and r = −0.38, p < 0.001, respectively), we demonstrated that overall CVH score (β = −0.262; SE = 0.077; p = 0.001), as well as BMI (β = −1.305; SE = 0.194; p < 0.001) and blood pressure CVH metrics (β = −0.607; SE = 0.206; p = 0.004) were significantly associated with EAT thickness but not with IMT. Conclusions: Our study is important as it demonstrated for the first time that CVH is associated with EAT thickness. Interestingly, this relationship seems to be dependent on BMI and blood pressure rather than on the other CVH metrics. However, outcome-driven studies are required to confirm these findings.

Role of Perivascular Adipose Tissue in Health and Disease

Perivascular adipose tissue (PVAT) is cushion of fat tissue surrounding blood vessels, which is phenotypically different from other adipose tissue depots. PVAT is composed of adipocytes and stromal vascular fraction, constituted by different populations of immune cells, endothelial cells, and adipose-derived stromal cells. It expresses and releases an important number of vasoactive factors with paracrine effects on vascular structure and function. In healthy individuals, these factors elicit a net anticontractile and anti-inflammatory paracrine effect aimed at meeting hemodynamic and metabolic demands of specific organs and regions of the body. Pathophysiological situations, such as obesity, diabetes or hypertension, induce changes in its amount and in the expression pattern of vasoactive factors leading to a PVAT dysfunction in which the beneficial paracrine influence of PVAT is shifted to a pro-oxidant, proinflammatory, contractile, and trophic environment leading to functional and structural cardiovascular alterations and cardiovascular disease. Many different PVATs surrounding a variety of blood vessels have been described and exhibit regional differences. Both protective and deleterious influence of PVAT differs regionally depending on the specific vascular bed contributing to variations in the susceptibility of arteries and veins to vascular disease. PVAT therefore, might represent a novel target for pharmacological intervention in cardiovascular disease. © 2018 American Physiological Society. Compr Physiol 8:23-59, 2018.

Postmenopausal Women With Greater Paracardial Fat Have More Coronary Artery Calcification Than Premenopausal Women: The Study of Women's Health Across the Nation (SWAN) Cardiovascular Fat Ancillary Study

Background

Volumes of paracardial adipose tissue (PAT) and epicardial adipose tissue (EAT) are greater after menopause. Interestingly, PAT but not EAT is associated with estradiol decline, suggesting a potential role of menopause in PAT accumulation. We assessed whether volumes of heart fat depot (EAT and PAT) were associated with coronary artery calcification (CAC) in women at midlife and whether these associations were modified by menopausal status and estradiol levels.

Methods and Results

EAT and PAT volumes and CAC were measured using electron beam computed tomography scans. CAC was evaluated as (1) the presence of CAC (CAC Agatston score ≥10) and (2) the extent of any CAC (log CAC Agatston score >0). The study included 478 women aged 50.9 years (58% pre‐ or early perimenopausal, 10% late perimenopausal, and 32% postmenopausal). EAT was significantly associated with CAC measures, and these associations were not modified by menopausal status or estradiol. In contrast, associations between PAT and CAC measures were modified by menopausal status (interaction‐P≤0.01). Independent of study covariates including other adiposity measures, each 1‐SD unit increase in log PAT was associated with 102% higher risk of CAC presence (P=0.04) and an 80% increase in CAC extent (P=0.008) in postmenopausal women compared with pre‐ or early perimenopausal women. Additional adjustment for estradiol and hormone therapy attenuated these differences. Moreover, the association between PAT and CAC extent was stronger in women with lower estradiol levels (interaction P=0.004).

Conclusions

The findings suggest that PAT is a potential menopause‐specific coronary artery disease risk marker, supporting the need to monitor and target this fat depot for intervention in women at midlife.

High aminopeptidase A activity contributes to blood pressure control in ob/ob mice by AT2 receptor-dependent mechanism

Obesity is assumed to be a major cause of human essential hypertension; however, the mechanisms responsible for weight-related increase in blood pressure (BP) are not fully understood. The prevalence of hypertension induced by obesity has grown over the years, and the role of the renin-angiotensin-aldosterone system (RAAS) in this process continues to be elucidated. In this scenario, the ob/ob mice are a genetic obesity model generally used for metabolic disorder studies. These mice are normotensive even though they present several metabolic conditions that predispose them to hypertension. Although the normotensive trait in these mice is associated with the poor activation of sympathetic nervous system by the lack of leptin, we demonstrated that ob/ob mice present massively increased aminopeptidase A (APA) activity in the circulation. APA enzyme metabolizes angiotensin (ANG) II into ANG III, a peptide associated with intrarenal angiotensin type 2 (AT₂) receptor activation and induction of natriuresis. In these mice, we found increased ANG-III levels in the circulation, high AT₂ receptor expression in the kidney, and enhanced natriuresis. AT₂ receptor blocking and APA inhibition increased BP, suggesting the ANG III-AT₂ receptor axis as a complementary BP control mechanism. Circulating APA activity was significantly reduced by weight loss independently of leptin, indicating the role of fat tissue in APA production. Therefore, in this study we provide new data supporting the role of APA in BP control in ob/ob mouse strain. These findings improve our comprehension about obesity-related hypertension and suggest new tools for its treatment.NEW & NOTEWORTHY In this study, we reported an increased angiotensin III generation in the circulation of ob/ob mice caused by a high aminopeptidase A activity. These findings are associated with an increased natriuresis found in these mice and support the role of renin-angiotensin-aldosterone system as additional mechanism regulating blood pressure in this genetic obese strain.

Effect of menopausal hormone therapy on components of the metabolic syndrome

The world population is aging, and women will spend an increasing share of their lives in a postmenopausal state that predisposes to metabolic dysfunction. Thus, the prevalence of metabolic syndrome (MetS) in women is likely to increase dramatically. This article summarizes the effects of menopause in predisposing to components of MetS including visceral obesity, dyslipidemia, type 2 diabetes (T2D) and hypertension (HTN). We also summarize the effects of menopausal hormone therapy (MHT) in reversing these metabolic alterations and discuss therapeutic advances of novel menopausal treatment on metabolic function.

Epicardial Adipose Tissue Thickness and Its Association With the Presence and Severity of Coronary Artery Disease in Clinical Setting: A Cross-Sectional Observational Study

Background

Obesity is an important risk factor for atherosclerotic cardiovascular disease (ASCVD). Estimation of visceral adipose tissue is important and several methods are available as its surrogate. Although correlation of epicardial adipose tissue (EAT) with visceral adipose tissue as estimated by magnetic resonance imaging (MRI) and/or CT is excellent, it is costlier and cumbersome. EAT can be accurately measured by two-dimensional (2D) echocardiography. It tends to be higher in patients with acute coronary syndrome than in subjects without coronary artery disease (CAD) and in those with stable angina. It also carries advantage as index of high cardiometabolic risk as it is a direct measure of visceral fat rather than anthropometric measurements. The present study evaluated the relationship of EAT to the presence and severity of CAD in clinical setting.

Methods

In this prospective, single-center study conducted in the Department of Cardiology, LPS Institute of Cardiology, Kanpur, India, 549 consecutive patients with acute coronary syndrome or chronic stable angina were enrolled. Sensitivity, specificity, and receiver operating characteristic (ROC) curve were estimated to find cut-off value of EAT thickness for diagnosing CAD using coronary angiographic findings as gold standard.

Results

Patients were diagnosed as CAD group (n = 464, 60.30 ± 8.36 years) and non-CAD group (n = 85, 54.42 ± 11.93 years) after assessing coronary angiograms. The EAT was measured at end-systole from the PLAX views of three cardiac cycles on the free wall of the right ventricle. Lesion was significant if > 50% in left main and > 70% in other coronary arteries. The mean EAT thickness in CAD group was 5.10 ± 1.06 and in non-CAD group was 4.36 ± 1.01 which was significant (P = 0.003). Significant correlation was demonstrated between EAT thickness and presence of CAD (P < 0.003). Higher EAT was associated with severe CAD and presence of multivessel disease. By ROC analysis, EAT > 4.65 mm predicated the presence of significant coronary stenosis by 71.6% sensitivity and 73.1% specificity.

Conclusion

EAT thickness measured using transthoracic echocardiography (TTE) significantly correlates with the presence and severity of CAD. It is sensitive, easily available, and cost-effective and assists in the risk stratification and may be an additional marker on classical risk factors for CAD.

Early atherosclerosis in normotensive patients with autosomal dominant polycystic kidney disease: the relation between epicardial adipose tissue thickness and carotid intima-media thickness

Epicardial adipose tissue thickness (EATT) is suggested as a novel marker of subclinical atherosclerosis. Despite increased carotid intima-media thickness (CIMT) in autosomal dominant polycystic kidney disease (ADPKD) patients, the extent of the relationship between CIMT and EATT is unknown. The main purpose of our study was to evaluate the relation between EATT and CIMT in normotensive ADPKD patients with well-preserved renal function. Fifty-five normotensive ADPKD patients with normal renal function and 50 healthy control subjects were included in the study. EATT and CIMT were measured by echocardiography in all subjects. Correlation between EATT and CIMT was evaluated in ADPKD patients, while multivariate linear regression analysis was performed to determine factors predicting EATT and CIMT. ADPKD patients had significantly higher levels CIMT [0.7 (0.4–1.2) vs. 0.5 (0.4–0.8) mm, p < 0.001] and EATT (6.8 ± 2.7 vs. 4.8 ± 1.2 mm, p < 0.001) as compared with control subjects. Significant positive correlation was found between EATT and CIMT (r = 0.58, p < 0.001). Higher CRP levels (OR 54.7, 95 % CI 37.44–72.01, p < 0.001) and having ADPKD (OR 10.2, 95 % CI 2.53–17.86, p = 0.01) were the only independent factors associated with a higher EATT. A higher age (OR 0.35, 95 % CI −0.02 to 0.71, p = 0.06) tended to be independently associated with a higher EATT. In conclusion, our findings suggest that EATT, being simply measured by echocardiography and correlated with CIMT, can be used to detect subclinical atherosclerosis in normotensive ADPKD patients.

Is the Amount of Coronary Perivascular Fat Related to Atherosclerosis?

Interesting and stimulating data about the effect of the perivascular adipose tissue size on atherogenesis are based mainly on CT findings. We studied this topic by directly analyzing perivascular adipose tissue in explanted hearts from patients undergoing transplantation. Ninety-six consecutive patients were included, including 58 with atherosclerotic coronary heart disease (CHD) and 38 with dilation cardiomyopathy (DCMP). The area of perivascular fat, area of the coronary artery wall, and ratio of CD68-positive macrophages within the perivascular fat and within the vascular wall were quantified by immunohistochemistry. There was no significant difference in the perivascular adipose tissue size between the two groups. Nevertheless, there was a significantly higher number of macrophages in the coronary arterial wall of CHD patients. In addition, we found a close relationship between the ratio of macrophages in the arterial wall and adjacent perivascular adipose tissue in the CHD group, but not in the DCMP group. According to our data interaction between macrophages in the arterial wall and macrophages in surrounding adipose tissue could be more important mechanism of atherogenesis than the size of this tissue itself.

Molecular Pathways Regulating Macrovascular Pathology and Vascular Smooth Muscle Cells Phenotype in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) is a disease reaching a pandemic proportion in developed countries and a major risk factor for almost all cardiovascular diseases and their adverse clinical manifestations. T2DM leads to several macrovascular and microvascular alterations that influence the progression of cardiovascular diseases. Vascular smooth muscle cells (VSMCs) are fundamental players in macrovascular alterations of T2DM patients. VSMCs display phenotypic and functional alterations that reflect an altered intracellular biomolecular scenario of great vessels of T2DM patients. Hyperglycemia itself and through intraparietal accumulation of advanced glycation-end products (AGEs) activate different pathways, in particular nuclear factor-κB and MAPKs, while insulin and insulin growth-factor receptors (IGFR) are implicated in the activation of Akt and extracellular-signal-regulated kinases (ERK) 1/2. Nuclear factor-κB is also responsible of increased susceptibility of VSMCs to pro-apoptotic stimuli. Down-regulation of insulin growth-factor 1 receptors (IGFR-1R) activity in diabetic vessels also influences negatively miR-133a levels, so increasing apoptotic susceptibility of VSMCs. Alterations of those bimolecular pathways and related genes associate to the prevalence of a synthetic phenotype of VSMCs induces extracellular matrix alterations of great vessels. A better knowledge of those biomolecular pathways and related genes in VSMCs will help to understand the mechanisms leading to macrovascular alterations in T2DM patients and to suggest new targeted therapies.

Cardiovascular Fat, Menopause, and Sex Hormones in Women: The SWAN Cardiovascular Fat Ancillary Study

CONTEXT

Cardiovascular risk increases in women after menopause. Mounting evidence demonstrates a role of cardiovascular fat (CF) in the pathogenesis of coronary heart disease, but no research has examined CF in relation to sex hormones or menopausal status in women.

OBJECTIVE

The objective was to determine the relationship between CF depots, menopausal status, and endogenous sex hormones.

DESIGN

Cross-sectional and longitudinal study designs were used.

SETTING

The setting included the Study of Women's Health Across the Nation (SWAN) Heart and Cardiovascular Fat Ancillary Study.

PARTICIPANTS

A total of 456 women (mean age, 50.75 y); 62% premenopausal/early perimenopausal, and 38% late peri-/postmenopausal.

INTERVENTION

Menopausal status, endogenous sex hormones measured simultaneously with CF volumes, and circulating estradiol available 4.80 years (median) before CF measures.

MAIN OUTCOME MEASURES

Volumes of CF (epicardial adipose tissue [EAT], paracardial adipose tissue [PAT], total heart adipose tissue [TAT = EAT + PAT], and aortic perivascular adipose tissue [PVAT]).

RESULTS

In final models, late peri-/postmenopausal women had 9.88% more EAT, 20.72% more PAT, and 11.69% more TAT volumes than pre-/early perimenopausal women (P < .05). PVAT was not associated with menopausal status. In final models, lower estradiol concentrations were associated with greater volumes of PAT and TAT (P < .05). Women with the greatest reduction in estradiol since baseline had greater volumes of PAT compared to women with the least reduction (P = .02).

CONCLUSIONS

Late peri-/postmenopausal women have greater volumes of heart fat compared with pre-/early perimenopausal women independent of age, obesity, and other covariates. Endogenous sex hormones are associated with CF. Perhaps CF plays a role in the higher risk of coronary heart disease reported in women after menopause.

Human epicardial adipose tissue has a specific transcriptomic signature depending on its anatomical peri-atrial, peri-ventricular, or peri-coronary location

AIMS

Human epicardial adipose tissue (EAT) is a visceral and perivascular fat that has been shown to act locally on myocardium, atria, and coronary arteries. Its abundance has been linked to coronary artery disease (CAD) and atrial fibrillation. However, its physiological function remains highly debated. The aim of this study was to determine a specific EAT transcriptomic signature, depending on its anatomical peri-atrial (PA), peri-ventricular (PV), or peri-coronary location.

METHODS AND RESULTS

Samples of EAT and thoracic subcutaneous fat, obtained from 41 patients paired for cardiovascular risk factors, CAD, and atrial fibrillation were analysed using a pangenomic approach. We found 2728 significantly up-regulated genes in the EAT vs. subcutaneous fat with 400 genes being common between PA, PV, and peri-coronary EAT. These common genes were related to extracellular matrix remodelling, inflammation, infection, and thrombosis pathways. Omentin (ITLN1) was the most up-regulated gene and secreted adipokine in EAT (fold-change >12, P < 0.0001). Among EAT-enriched genes, we observed different patterns depending on adipose tissue location. A beige expression phenotype was found in EAT but PV EAT highly expressed uncoupled protein 1 (P = 0.01). Genes overexpressed in peri-coronary EAT were implicated in proliferation, O-N glycan biosynthesis, and sphingolipid metabolism. PA EAT displayed an atypical pattern with genes implicated in cardiac muscle contraction and intracellular calcium signalling pathway.

CONCLUSION

This study opens new perspectives in understanding the physiology of human EAT and its local interaction with neighbouring structures.

Perivascular adipose tissue-derived adiponectin inhibits collar-induced carotid atherosclerosis by promoting macrophage autophagy

OBJECTIVES

Adiponectin (APN) secreted from perivascular adipose tissue (PVAT) is one of the important anti-inflammatory adipokines to inhibit the development of atherosclerosis, but the underlying mechanism has not been clarified. In this study, we aimed to elucidate how APN regulates plaque formation in atherosclerosis.

METHODS AND RESULTS

To assess the role of APN secreted by PVAT in atherosclerosis progression, we performed PVAT transplantation experiments on carotid artery atherosclerosis model: ApoE knockout (ApoE-/-) mice with a perivascular collar placement around the left carotid artery in combination with a high-fat diet feeding. Our results show that the ApoE-/- mice with PVAT derived from APN knockout (APN-/-) mice exhibited accelerated plaque volume formation compared to ApoE-/- mice transplanted with wild-type littermate tissue. Conversely, autophagy in macrophages was significantly attenuated in ApoE-/- mice transplanted with APN-/- mouse-derived PVAT compared to controls. Furthermore, in vitro studies indicate that APN treatment increased autophagy in primary macrophages, as evidenced by increased LC3-I processing and Beclin1 expression, which was accompanied by down-regulation of p62. Moreover, our results demonstrate that APN promotes macrophage autophagy via suppressing the Akt/FOXO3a signaling pathway.

CONCLUSIONS

Our results indicate that PVAT-secreted APN suppresses plaque formation by inducing macrophage autophagy.

Co-cultivation of human aortic smooth muscle cells with epicardial adipocytes affects their proliferation rate

The abnormal proliferation of vascular smooth muscle cells (VSMC) is thought to play a role in the pathogenesis of atherosclerosis. Adipocytes produce several bioactive paracrine substances that can affect the growth and migration of VSMCs. Our study focuses on the direct effect of the bioactive substances in conditioned media (CM) that was obtained by incubation with primary adipocyte-derived cell lines, including cell lines derived from both preadipocytes and from more mature cells, on the proliferation rate of human aortic smooth muscle cells (HAoSMCs). We used a Luminex assay to measure the adipokine content of the CM and showed that there was a higher concentration of monocyte chemoattractant protein-1 in renal preadipocyte-CM compared with the HAoSMC control (p<0.5). The addition of both renal preadipocyte- and epicardial adipocyte- CM resulted in the elevated production of vascular endothelial growth factor compared with the control HASoSMC CM (p<0.001). The adiponectin content in renal adipocyte-CM was increased compared to all the remaining adipocyte-CM (p<0.01). Moreover, the results showed a higher proliferation rate of HAoSMCs after co-culture with epicardial adipocyte-CM compared to the HAoSMC control (p<0.05). These results suggest that bioactive substances produced by adipocytes have a stimulatory effect on the proliferation of VSMCs.

Perivascular adipose tissue inhibits endothelial function of rat aortas via caveolin-1

Perivascular adipose tissue (PVAT)-derived factors have been proposed to play an important role in the pathogenesis of atherosclerosis. Caveolin-1 (Cav-1), occupying the calcium/calmodulin binding site of endothelial NO synthase (eNOS) and then inhibiting nitric oxide (NO) production, is also involved in the development of atherosclerosis. Thus, we investigated whether PVAT regulated vascular tone via Cav-1 and/or endothelial NO pathways. Isometric tension studies were carried out in isolated thoracic aortas from Wistar rats in the presence and absence of PVAT. Concentration-response curves of phenylephrine, acetylcholine, and sodium nitroprusside were illustrated to examine the vascular reactivity and endothelial function. The protein expressions of eNOS and Cav-1 were also examined in aortic homogenates. Our results demonstrated that PVAT significantly enhanced vasoconstriction and inhibited vasodilatation via endothelium-dependent mechanism. The aortic NO production was diminished after PVAT treatment, whereas protein expression and activity of eNOS were not significantly affected. In addition, Cav-1 protein expression was significantly increased in aortas with PVAT transfer. Furthermore, a caveolae depleter methyl-β-cyclodextrin abolished the effect of PVAT on the enhancement of vasoconstriction, and reversed the impairment of aortic NO production. In conclusion, unknown factor(s) released from PVAT may inhibit endothelial NO production and induce vasocontraction via an increase of Cav-1 protein expression.

Increased epicardial adipose tissue thickness as a predictor for hypertension: a cross-sectional observational study

The aim of the study was to determine whether epicardial adipose tissue thickness (EAT), a new cardiometabolic risk factor, is associated with essential hypertension. The sample included 127 asymptomatic patients with one or more cardiovascular risk factors consecutively referred for cardiac computed tomography angiography. Data were collected retrospectively and compared between hypertensive (n=39) and normotensive (n=88) patients. The hypertensive patients had a significantly higher mean EAT thickness than the normotensive group (2.81±1.6 mm vs 2.07±1.43 mm; P=.011) and a significantly elevated mean coronary artery calcium score (316.8±512.6 vs 108.73±215; P=.0257). The odds ratio for a patient with tissue thickness ≥2.4 mm having hypertension was 1.396 (95% confidence interval, 1.033-1.922). Factors independently associated with hypertension were body mass index, low-density lipoprotein, and age. A model score was developed using the logistic regression coefficients for calculation of individual risk. Hypertensive patients have significantly higher than normal EAT thickness. Epicardial adipose tissue thickness may serve as a risk indicator for hypertension and cardiovascular morbidity.

Perivascular adipose tissue-secreted angiopoietin-like protein 2 (Angptl2) accelerates neointimal hyperplasia after endovascular injury

Much attention is currently focused on the role of perivascular adipose tissue in development of cardiovascular disease (CVD). Some researchers view it as promoting CVD through secretion of cytokines and growth factors called adipokines, while recent reports reveal that perivascular adipose tissue can exert a protective effect on CVD development. Furthermore, adiponectin, an anti-inflammatory adipokine, reportedly suppresses neointimal hyperplasia after endovascular injury, whereas such vascular remodeling is enhanced by pro-inflammatory adipokines secreted by perivascular adipose, such as tumor necrosis factor-α (TNF-α). These findings suggest that extent of vascular remodeling, a pathological process associated with CVD development, depends on the balance between pro- and anti-inflammatory adipokines secreted from perivascular adipose tissue. We previously demonstrated that angiopoietin-like protein 2 (Angptl2), a pro-inflammatory factor secreted by adipose tissue, promotes adipose tissue inflammation and subsequent systemic insulin resistance in obesity. Here, we examined whether Angptl2 secreted by perivascular adipose tissue contributes to vascular remodeling after endovascular injury in studies of transgenic mice expressing Angptl2 in adipose tissue (aP2-Angptl2 transgenic mice) and Angptl2 knockout mice (Angptl2(-/-) mice). To assess the role of Angptl2 secreted by perivascular adipose tissue on vascular remodeling after endovascular injury, we performed adipose tissue transplantation experiments using these mice. Wild-type mice with perivascular adipose tissue derived from aP2-Angptl2 mice exhibited accelerated neointimal hyperplasia after endovascular injury compared to wild-type mice transplanted with wild-type tissue. Conversely, vascular inflammation and neointimal hyperplasia after endovascular injury were significantly attenuated in wild-type mice transplanted with Angptl2(-/-) mouse-derived perivascular adipose tissue compared to wild-type mice transplanted with wild-type tissue. RT-PCR analysis revealed that mouse Angptl2 expression in perivascular adipose tissue was significantly increased by aging, hypercholesterolemia, and endovascular injury, all risk factors for coronary heart disease (CHD). Immunohistochemical and RT-PCR analysis of tissues from patients with CHD and from non-CHD patients indicated that ANGPTL2 expression in epicardial adipose tissue was unchanged. Interestingly, that analysis also revealed a positive correlation in ANGPTL2 and ADIPONECTIN expression in epicardial adipose tissue of non-CHD patients, a correlation not seen in CHD patients. However, in epicardial adipose tissue from CHD patients, ANGPTL2 expression was positively correlated with that of TNF-α, a correlation was not seen in non-CHD patients. These findings suggest that pro-inflammatory adipokines cooperatively accelerate CHD development and that maintaining a balance between pro- and anti-inflammatory adipokines likely protects non-CHD patients from developing CHD. Overall, our studies demonstrate that perivascular adipose tissue-secreted Angptl2 accelerates vascular inflammation and the subsequent CVD development.

Adipocyte deficiency of angiotensinogen prevents obesity-induced hypertension in male mice

Previous studies demonstrated that diet-induced obesity increased plasma angiotensin II concentrations and elevated systolic blood pressures in male mice. Adipocytes express angiotensinogen and secrete angiotensin peptides. We hypothesize that adipocyte-derived angiotensin II mediates obesity-induced increases in systolic blood pressure in male high fat-fed C57BL/6 mice. Systolic blood pressure was measured by radiotelemetry during week 16 of low-fat or high-fat feeding in Agt(fl/fl) and adipocyte angiotensinogen-deficient mice (Agt(aP2)). Adipocyte angiotensinogen deficiency had no effect on diet-induced obesity. Basal 24-hour systolic blood pressure was not different in low fat-fed Agt(fl/fl) compared with Agt(aP2) mice (124 ± 3 versus 128 ± 3 mm Hg, respectively). In Agt(fl/fl) mice, high-fat feeding significantly increased systolic blood pressure (24 hours; 134 ± 2 mm Hg; P<0.05). In contrast, high fat-fed Agt(aP2) mice did not exhibit an increase in systolic blood pressure (126 ± 2 mm Hg). Plasma angiotensin II concentrations were increased by high-fat feeding in Agt(fl/fl) mice (low fat, 32 ± 14; high fat, 219 ± 58 pg/mL; P<0.05). In contrast, high fat-fed Agt(aP2) mice did not exhibit elevated plasma angiotensin II concentrations (high fat, 18 ± 7 pg/mL). Similarly, adipose tissue concentrations of angiotensin II were significantly decreased in low fat- and high fat-fed Agt(aP2) mice compared with controls. In conclusion, adipocyte angiotensinogen deficiency prevented high fat-induced elevations in plasma angiotensin II concentrations and systolic blood pressure. These results suggest that adipose tissue serves as a major source of angiotensin II in the development of obesity hypertension.

Differential impact of oleate, palmitate, and adipokines on expression of NF-κB target genes in human vascular smooth muscle cells

It is widely accepted that obesity is a major risk factor for the development of atherosclerosis. In this context, adipose tissue produces a variety of adipokines and releases free fatty acids, contributing to a chronic-low grade inflammation state implicated in vascular complications. In this study, we investigated the role of adipokines, oleic acid (OA), palmitic acid (PA), and the combinations on activation of NF-κB target genes in human vascular smooth muscle cells (SMC) to assess the hypothesis of synergistic interactions between these molecules. Adipocyte-conditioned medium (CM), generated from human adipocytes, in combination with low concentrations of OA, but not PA, induces SMC proliferation and activation of the transcription factor NF-κB in a synergistic way. Combined treatment of CM and OA further regulates a set of downstream NF-κB target genes including angiopoietin-1, activin A, and MMP-1, all critically involved in SMC dysfunction. This suggests that the lipotoxic potential of fatty acids is substantially enhanced by the presence of adipocyte-derived factors.

Loss of perivascular adipose tissue on peroxisome proliferator-activated receptor-γ deletion in smooth muscle cells impairs intravascular thermoregulation and enhances atherosclerosis

BACKGROUND

Perivascular adipose tissue (PVAT) surrounds most vessels and shares common features with brown adipose tissue (BAT). Although adaptive thermogenesis in BAT increases energy expenditure and is beneficial for metabolic diseases, little is known about the role of PVAT in vascular diseases such as atherosclerosis. We hypothesize that the thermogenic function of PVAT regulates intravascular temperature and reduces atherosclerosis.

METHODS AND RESULTS

PVAT shares similar structural and proteomics with BAT. We demonstrated that PVAT has thermogenic properties similar to BAT in response to cold stimuli in vivo. Proteomics analysis of the PVAT from mice housed in a cold environment identified differential expression in proteins highly related to cellular metabolic processes. In a mouse model deficient in peroxisome proliferator-activated receptor-γ in smooth muscle cells (SMPG KO mice), we uncovered a complete absence of PVAT surrounding the vasculature, likely caused by peroxisome proliferator-activated receptor-γ deletion in the perivascular adipocyte precursor cells as well. Lack of PVAT, which results in loss of its thermogenic activity, impaired vascular homeostasis, which caused temperature loss and endothelial dysfunction. We further showed that cold exposure inhibits atherosclerosis and improves endothelial function in mice with intact PVAT but not in SMPG KO mice as a result of impaired lipid clearance. Proinflammatory cytokine expression in PVAT is not altered on exposure to cold. Finally, prostacyclin released from PVAT contributes to the vascular protection against endothelial dysfunction.

CONCLUSIONS

PVAT is a vasoactive organ with functional characteristics similar to BAT and is essential for intravascular thermoregulation of cold acclimation. This thermogenic capacity of PVAT plays an important protective role in the pathogenesis of atherosclerosis.

Loss of perivascular adipose tissue on peroxisome proliferator-activated receptor-γ deletion in smooth muscle cells impairs intravascular thermoregulation and enhances atherosclerosis

BACKGROUND

Perivascular adipose tissue (PVAT) surrounds most vessels and shares common features with brown adipose tissue (BAT). Although adaptive thermogenesis in BAT increases energy expenditure and is beneficial for metabolic diseases, little is known about the role of PVAT in vascular diseases such as atherosclerosis. We hypothesize that the thermogenic function of PVAT regulates intravascular temperature and reduces atherosclerosis.

METHODS AND RESULTS

PVAT shares similar structural and proteomics with BAT. We demonstrated that PVAT has thermogenic properties similar to BAT in response to cold stimuli in vivo. Proteomics analysis of the PVAT from mice housed in a cold environment identified differential expression in proteins highly related to cellular metabolic processes. In a mouse model deficient in peroxisome proliferator-activated receptor-γ in smooth muscle cells (SMPG KO mice), we uncovered a complete absence of PVAT surrounding the vasculature, likely caused by peroxisome proliferator-activated receptor-γ deletion in the perivascular adipocyte precursor cells as well. Lack of PVAT, which results in loss of its thermogenic activity, impaired vascular homeostasis, which caused temperature loss and endothelial dysfunction. We further showed that cold exposure inhibits atherosclerosis and improves endothelial function in mice with intact PVAT but not in SMPG KO mice as a result of impaired lipid clearance. Proinflammatory cytokine expression in PVAT is not altered on exposure to cold. Finally, prostacyclin released from PVAT contributes to the vascular protection against endothelial dysfunction.

CONCLUSIONS

PVAT is a vasoactive organ with functional characteristics similar to BAT and is essential for intravascular thermoregulation of cold acclimation. This thermogenic capacity of PVAT plays an important protective role in the pathogenesis of atherosclerosis.

Epicardial adipose tissue: emerging physiological, pathophysiological and clinical features

Epicardial adipose tissue is an unusual visceral fat depot with anatomical and functional contiguity to the myocardium and coronary arteries. Under physiological conditions, epicardial adipose tissue displays biochemical, mechanical and thermogenic cardioprotective properties. Under pathological circumstances, epicardial fat can locally affect the heart and coronary arteries through vasocrine or paracrine secretion of proinflammatory cytokines. What influences this equilibrium remains unclear. Improved local vascularization, weight loss, and targeted pharmaceutical interventions could help to return epicardial fat to its physiological role. This review focuses on the emerging physiological and pathophysiological aspects of the epicardial fat and its numerous and innovative clinical applications. Particular emphasis is placed on the paracrine/endocrine properties of epicardial fat and its role in the development and progression of atherosclerosis.

A new look at the renin-angiotensin system--focusing on the vascular system

The renin-angiotensin system (RAS), critically involved in the control of blood pressure and volume homeostasis, is a dual system comprising a circulating component and a local tissue component. The rate limiting enzyme is renin, which in the circulating RAS derives from the kidney to generate Ang II, which in turn regulates cardiovascular function by binding to AT(1) and AT(2) receptors on cardiac, renal and vascular cells. The tissue RAS can operate independently of the circulating RAS and may be activated even when the circulating RAS is suppressed or normal. A functional tissue RAS has been identified in brain, kidney, heart, adipose tissue, hematopoietic tissue, gastrointestinal tract, liver, endocrine system and blood vessels. Whereas angiotensinsinogen, angiotensin converting enzyme (ACE), Ang I and Ang II are synthesized within these tissues, there is still controversy as to whether renin is produced locally or whether it is taken up from the circulation, possibly by the (pro)renin receptor. This is particularly true in the vascular wall, where expression of renin is very low. The exact function of the vascular RAS remains elusive, but may contribute to fine-tuning of vascular tone and arterial structure and may amplify vascular effects of the circulating RAS, particularly in pathological conditions, such as in hypertension, atherosclerosis and diabetes. New concepts relating to the vascular RAS have recently been elucidated including: (1) the presence of functionally active Ang-(1-7)-Mas axis in the vascular system, (2) the importance of the RAS in perivascular adipose tissue and cross talk with vessels, and (3) the contribution to vascular RAS of Ang II derived from immune and inflammatory cells within the vascular wall. The present review highlights recent progress in the RAS field, focusing on the tissue system and particularly on the vascular RAS.

Epicardial adipose tissue and relationship with coronary artery disease

Epicardial adipose tissue (EAT) is metabolically active tissue that accumulates around the coronary arteries. Epicardial fat is a rich source of free fatty acids and may contribute to local inflammatory load by increased synthesis of inflammatory cytokines. Direct passage of bioactive molecules into the coronary arteries due to close contact with the vascular wall and the lack of fascia may contribute to the pathogenesis of coronary artery disease. Direct correlation between visceral fat and EAT defines the latter as an indirect marker of intra-abdominal visceral adiposity. EAT is related to anthropometric and clinical features of the metabolic syndrome (MS) and to hepatic transaminases as markers of steatohepatitis. An increase in EAT thickness is related to an increase in left ventricular mass and is correlated with atrial enlargement and impairment in diastolic filling in obesity. Echocardiographic study of EAT is an easy and reliable imaging indicator of visceral adiposity and cardiovascular risk. EAT is an independent factor strongly correlated with significant coronary stenosis. A level of EAT above an established average value can be considered a predictive marker of cardiovascular risk. We review the most recent studies proving the specific active role of EAT in the development of cardiac disease.

Epicardial fat gene expression after aerobic exercise training in pigs with coronary atherosclerosis: relationship to visceral and subcutaneous fat

Epicardial adipose tissue (EAT) is contiguous with coronary arteries and myocardium and potentially may play a role in coronary atherosclerosis (CAD). Exercise is known to improve cardiovascular disease risk factors. The purpose of this study was to investigate the effect of aerobic exercise training on the expression of 18 genes, measured by RT-PCR and selected for their role in chronic inflammation, oxidative stress, and adipocyte metabolism, in peri-coronary epicardial (cEAT), peri-myocardial epicardial (mEAT), visceral abdominal (VAT), and subcutaneous (SAT) adipose tissues from a castrate male pig model of familial hypercholesterolemia with CAD. We tested the hypothesis that aerobic exercise training for 16 wk would reduce the inflammatory profile of mRNAs in both components of EAT and VAT but would have little effect on SAT. Exercise increased mEAT and total heart weights. EAT and heart weights were directly correlated. Compared with sedentary pigs matched for body weight to exercised animals, aerobic exercise training reduced the inflammatory response in mEAT but not cEAT, had no effect on inflammatory genes but preferentially decreased expression of adiponectin and other adipocyte-specific genes in VAT, and had no effect in SAT except that IL-6 mRNA went down and VEGFa mRNA went up. We conclude that 1) EAT is not homogeneous in its inflammatory response to aerobic exercise training, 2) cEAT around CAD remains proinflammatory after chronic exercise, 3) cEAT and VAT share similar inflammatory expression profiles but different metabolic mRNA responses to exercise, and 4) gene expression in SAT cannot be extrapolated to VAT and heart adipose tissues in exercise intervention studies.