Thoracic periaortic and visceral adipose tissue and their cross-sectional associations with measures of vascular function

Single-nucleus analysis of thoracic perivascular adipose tissue reveals critical changes in cell composition, communication, and gene regulatory networks induced by a high fat hypertensive diet

Cardiovascular disease (CVD) is the leading cause of death worldwide, with hypertension being its primary causal factor. Most blood vessels are surrounded by perivascular adipose tissue (PVAT), which regulates blood vessel tone through the secretion of vasoactive factors. PVAT is recognized as a key mediator of vascular function and dysfunction in CVD, although the underlying mechanisms remain poorly understood. To investigate PVAT's mechanistic role in hypertension, we performed single nucleus RNA-Sequencing analysis of thoracic aortic PVAT from Dahl SS rats fed a high-fat, hypertensive diet. Computational analysis revealed extensive diet-induced changes in cell-type composition, cell-type specific gene expression, cell-cell communication pathways, and intracellular gene regulatory networks within PVAT. Furthermore, we identified key transcription factors mediating these networks and demonstrated through virtual knock-out experiments that these factors could serve as potential therapeutic targets for preventing or reversing PVAT's hypertensive state.

Quantification of perivascular adipose tissue attenuation does not add incremental prognostic value in patients undergoing transcatheter aortic valve implantation

Aims

Perivascular adipose tissue attenuation (PVAT) has emerged as a novel coronary computed tomography angiography (CCTA)-based biomarker predicting cardiovascular events by capturing inflammation around the coronary arteries. We assessed whether PVAT adds incremental prognostic value in patients undergoing transcatheter aortic valve implantation (TAVI).

Methods and results

A total of 510 patients underwent CCTA imaging prior to TAVI between November 2015 and June 2020 at the Medical University of Vienna. PVAT was obtained from CCTA images and was measured around the right coronary artery [PVAT(RCA)] and the aortic valve [PVAT(valve)]. Following application of exclusion criteria, 372 patients [mean age 80.6 ± 6.8 years; 169 (45%) women] were analysed. Over a median follow-up of 3.0 (IQR 2.5-3.6) years, 52 (14%) individuals experienced a major adverse cardiovascular event (MACE, a composite of non-fatal stroke or myocardial infarction, cardiac death, or vascular intervention). Individuals exhibiting elevated PVAT[valve] displayed a heightened surgical risk according to European System for Cardiac Operative Risk Evaluation II, a lower body mass index, reduced left ventricular ejection fraction, prolonged hospitalization following TAVI, and elevated levels of circulating inflammatory markers compared with those in the low PVAT[valve] group (P < 0.05). However, neither PVAT[valve] nor PVAT[RCA] were independently associated with the occurrence of MACE in adjusted multi-variable analyses (PVAT[valve]: sub-distribution hazard ratio [SHR] 1.14, 95% CI:0.63-2.05, P = 0.672); PVAT[RCA]: SHR 1.16 [95% CI: 0.81-1.66], P = 0.417).

Conclusion

Measuring PVAT around either the right coronary artery or the aortic valve does not provide additional prognostic value beyond established risk factors for the prediction of MACE in patients undergoing TAVI.

Cardiometabolic implications of adipose tissue aging

Adipose tissue is a large endocrine organ that serves numerous physiological functions. As we age, adipose tissue remodels and can develop functional changes that alters its phenotype, potentially contributing to metabolic and cardiovascular disorders. Aging adipose tissue is characterized by regional redistribution of fat, accumulation of senescent cells, fibrosis, and decline in adipocyte differentiation capacities, which collectively impact adipose tissue function and whole body health. A notable transformation involves increased accumulation of intra-abdominal visceral adipose tissue and ectopic fat around internal organs such as the heart, blood vessels, liver, and kidneys that alter their functions. Other changes associated with aging include alterations in adipokine secretion and changes in adipocyte size and numbers. Aging adipocytes play a role in mediating chronic inflammation, metabolic dysfunction, and insulin resistance. Visceral adipose tissue, which increases in volume with aging, is in particular associated with inflammation, angiogenic dysfunction, and microvascular abnormalities, and mediators released by visceral fat may have adverse consequences systemically in multiple target organs, including the cardiovascular system. Understanding mechanisms underlying adipose tissue aging and its impact on cardiovascular health are important for developing interventions and treatments to promote healthy aging and reduce cardiometabolic disease risk.

The Implications of Aging on Vascular Health

Vascular aging encompasses structural and functional changes in the vasculature, significantly contributing to cardiovascular diseases, which are the leading cause of death globally. The incidence and prevalence of these diseases increase with age, with most morbidity and mortality attributed to myocardial infarction and stroke. Diagnosing and intervening in vascular aging while understanding the mechanisms behind age-induced vascular phenotypic and pathophysiological alterations offers the potential for delaying and preventing cardiovascular mortality in an aging population. This review delves into various aspects of vascular aging by examining age-related changes in arterial health at the cellular level, including endothelial dysfunction, cellular senescence, and vascular smooth muscle cell transdifferentiation, as well as at the structural level, including arterial stiffness and changes in wall thickness and diameter. We also explore aging-related changes in perivascular adipose tissue deposition, arterial collateralization, and calcification, providing insights into the physiological and pathological implications. Overall, aging induces phenotypic changes that augment the vascular system's susceptibility to disease, even in the absence of traditional risk factors, such as hypertension, diabetes, obesity, and smoking. Overall, age-related modifications in cellular phenotype and molecular homeostasis increase the vulnerability of the arterial vasculature to structural and functional alterations, thereby accelerating cardiovascular risk. Increasing our understanding of these modifications is crucial for success in delaying or preventing cardiovascular diseases. Non-invasive techniques, such as measuring carotid intima-media thickness, pulse wave velocity, and flow-mediated dilation, as well as detecting vascular calcifications, can be used for the early detection of vascular aging. Targeting specific pathological mechanisms, such as cellular senescence and enhancing angiogenesis, holds promise for innovative therapeutic approaches.

Lower estimates of myocardial perfusion are associated with greater aortic perivascular adipose tissue density in humans independent of aortic stiffness

Aortic perivascular adipose tissue (aPVAT) density is associated with age-related aortic stiffness in humans and therefore, may contribute to cardiovascular dysfunction. A lower subendocardial viability ratio (SEVR), an estimate of myocardial perfusion, indicates greater cardiovascular disease (CVD) risk and is associated with aortic stiffness in clinical populations. However, the influence of aortic stiffness on the relation between aPVAT density and SEVR/cardiovascular (CV) hemodynamics in apparently healthy adults is unknown. We hypothesize that greater aPVAT density will be associated with lower SEVR and higher CV hemodynamics independent of aortic stiffness. Fourteen (6 males/8 females; mean age, 55.4 ± 5.6 yr; body mass index, 25.5 ± 0.6 kg/m2) adults completed resting measures of myocardial perfusion (SEVR), CV hemodynamics (pulse wave analysis), aortic stiffness [carotid-femoral pulse wave velocity (cfPWV)], and a computed tomography scan to acquire aPVAT and visceral adipose tissue (VAT) density. Greater aPVAT density (i.e., higher density) was associated with lower SEVR (r = -0.78, P < 0.001) and a higher systolic pressure time integral (r = 0.49, P = 0.03), forward pulse height (r = 0.49, P = 0.03), reflected pulse height (r = 0.55, P = 0.02), ejection duration (r = 0.56, P = 0.02), and augmentation pressure (r = 0.69, P = 0.003), but not with the diastolic pressure time integral (r = -0.22, P = 0.22). VAT density was not associated with SEVR or any CV hemodynamic endpoints (all, P > 0.05). Furthermore, the relation between aPVAT density and SEVR remained after adjusting for aortic stiffness (r = -0.66, P = 0.01) but not age (r = -0.24, P > 0.05). These data provide initial evidence for aPVAT as a novel yet understudied local fat depot contributing to lower myocardial perfusion in apparently healthy adults with aging.NEW & NOTEWORTHY Aortic perivascular adipose tissue (aPVAT) density is associated with aging and aortic stiffness in humans and, therefore, may contribute to lower myocardial perfusion. We demonstrate that greater aPVAT, but not visceral adipose tissue density is associated with lower myocardial perfusion and augmentation pressure independent of aortic stiffness, but not independent of age. These data provide novel evidence for aPVAT as a potential therapeutic target to improve myocardial perfusion and cardiovascular function in humans with aging.

Dysregulation of mitochondrial dynamics mediated aortic perivascular adipose tissue-associated vascular reactivity impairment under excessive fructose intake

Excessive fructose intake presents the major risk factor for metabolic cardiovascular disease. Perivascular adipose tissue (PVAT) is a metabolic tissue and possesses a paracrine function in regulating aortic reactivity. However, whether and how PVAT alters vascular function under fructose overconsumption remains largely unknown. In this study, male Sprague-Dawley rats (8 weeks old) were fed a 60% high fructose diet (HFD) for 12 weeks. Fasting blood sugar, insulin, and triglycerides were significantly increased by HFD intake. Plasma adiponectin was significantly enhanced in the HFD group. The expression of uncoupling protein 1 (UCP1) and mitochondrial mass were reduced in the aortic PVAT of the HFD group. Concurrently, the expression of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) and mitochondrial transcription factor A (TFAM) were suppressed. Furthermore, decreased fusion proteins (OPA1, MFN1, and MFN2) were accompanied by increased fission proteins (FIS1 and phospho-DRP1). Notably, the upregulated α-smooth muscle actin (α-SMA) and osteocalcin in the PVAT were concurrent with the impaired reactivity of aortic contraction and relaxation. Coenzyme Q10 (Q, 10 mg/100 mL, 4 weeks) effectively reversed the aforementioned events induced by HFD. Together, these results suggested that the dysregulation of mitochondrial dynamics mediated HFD-triggered PVAT whitening to impair aortic reactivity. Fortunately, coenzyme Q10 treatment reversed HFD-induced PVAT whitening and aortic reactivity.

[Ectopic obesity in patients without manifested cardiovascular disease: regulations, frequency and clinical characteristics]

AIM

To determine the frequency, distribution and characteristics of ectopic obesity in patients without manifested cardiovascular disease.

MATERIALS AND METHODS

We examined 320 patients without manifested cardiovascular disease (average age 63.813.9 years), 38 of them without cardiovascular risk factors (healthy referent group). Anthropometric indicators were measured, body mass index (BMI) was calculated. Degree, type of obesity, lipid profile were evaluated. All patients underwent multi-detector chest computed tomography in spiral mode on Toshiba Aquilion Prime scanner using standardized protocol. Perivascular adipose tissue (PVAT) and pericardial adipose tissue (PAT) were detected using specialized semi-automatic software Tissue Composition Module QCTPro (Mindways Software, Inc., USA) after scanner calibration with special phantom. PAT and PVAT exceeding the 90th percentile in the healthy referent group were considered as ectopic obesity. Statistical analysis was performed using Statistica 10.0 software (StatSoft Inc., USA).

RESULTS

PAT volume 3.2 cm3 and PVAT volume 0.4 cm3 were criteria for high pericardial and high perivascular fat; 81 (25.2%) patients had ectopic obesity, 85 (26.5%) patients abdominal obesity; 146 (42.9%) people had high pericardial fat, 134 (39.4%) high perivascular fat. The frequency of ectopic obesity in patients with arterial hypertension (AH) was statistically significantly higher compared to persons without AH. Significantly more often ectopic forms of obesity were detected in patients with overweight and obesity. The high pericardial fat and high perivascular fat were found in patients with overweight and normal body weight. When comparing the clinical characteristics of patients with abdominal and ectopic obesity, metabolic parameters, as well as the incidence of hypertension and dyslipidemia, did not differ significantly.

CONCLUSION

Ectopic obesity can develop outside of global obesity. In addition, this type of obesity is accompanied by metabolic disorders and AH, regardless of the abdominal distribution of adipose tissue.

Perivascular adipose tissue-mediated arterial stiffening in aging and disease: An emerging translational therapeutic target?

Cardiovascular diseases (CVD) are the leading cause of mortality in modernized societies. Arterial stiffening with aging and disease is a key pathological event leading to increased CVD morbidity and mortality. Perivascular adipose tissue (PVAT) is a fat depot not widely studied yet has direct and profound effects on arterial stiffening. Identifying PVAT as a novel therapeutic target to lower arterial stiffness and thereby CVD risk has potentially important clinical ramifications. Thus, herein, we will overview the current preclinical evidence and the associated mechanisms for PVAT to promote arterial stiffness with aging and other disease conditions. We will also discuss viable translational lifestyle and pharmacological interventions for altering PVAT function that may de-stiffen arteries. Last, the translational potential for PVAT as a therapeutic target to lower arterial stiffness and CVD risk for clinical populations will be discussed.

The impact of visceral and general obesity on vascular and left ventricular function and geometry: a cross-sectional magnetic resonance imaging study of the UK Biobank

Aims 

We aimed to evaluate the associations of body fat distribution with cardiovascular function and geometry in the middle-aged general population.

Methods and results 

Four thousand five hundred and ninety participants of the UK Biobank (54% female, mean age 61.1 ± 7.2 years) underwent cardiac magnetic resonance for assessment of left ventricular (LV) parameters [end-diastolic volume (EDV), ejection fraction (EF), cardiac output (CO), and index (CI)] and magnetic resonance imaging for body composition analysis [subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)]. Body fat percentage (BF%) was assessed by bioelectrical impedance. Linear regressions were performed to assess the impact of visceral (VAT) and general (SAT and BF%) obesity on cardiac function and geometry. Visceral obesity was associated with a smaller EDV [VAT: β −1.74 (−1.15 to −2.33)], lower EF [VAT: β −0.24 (−0.12 to −0.35), SAT: β 0.02 (−0.04 to 0.08), and BF%: β 0.02 (−0.02 to 0.06)] and the strongest negative association with CI [VAT: β −0.05 (−0.06 to −0.04), SAT: β −0.02 (−0.03 to −0.01), and BF% β −0.01 (−0.013 to −0.007)]. In contrast, general obesity was associated with a larger EDV [SAT: β 1.01 (0.72–1.30), BF%: β 0.37 (0.23–0.51)] and a higher CO [SAT: β 0.06 (0.05–0.07), BF%: β 0.02 (0.01–0.03)]. In the gender-specific analysis, only men had a significant association between VAT and EF [β −0.35 (−0.19 to −0.51)].

Conclusion 

Visceral obesity was associated with a smaller LV EDV and subclinical lower LV systolic function in men, suggesting that visceral obesity might play a more important role compared to general obesity in LV remodelling.

Perivascular Adipose Tissue Inflammation in Ischemic Heart Disease

OBJECTIVE

There is growing recognition that adipose tissue-derived proatherogenic mediators contribute to obesity-related cardiovascular disease. We sought to characterize regional differences in perivascular adipose tissue (PVAT) phenotype in relation to atherosclerosis susceptibility. Approach and Results: We examined thoracic PVAT samples in 34 subjects (body mass index 32±6 kg/m², age 59±11 years) undergoing valvular, aortic, or coronary artery bypass graft surgeries and performed transcriptomic characterization using whole-genome expression profiling and quantitative polymerase chain reaction analyses. We identified a highly inflamed region of PVAT surrounding the human aortic root in close proximity to coronary takeoff and adjoining epicardial fat. In subjects undergoing coronary artery bypass graft, we found 300 genes significantly upregulated (false discovery rate Q<0.1) in paired samples of PVAT surrounding the aortic root compared with nonatherosclerotic left internal mammary artery. Genes encoding proteins mechanistically implicated in atherogenesis were enriched in aortic PVAT consisting of signaling pathways linked to inflammation, WNT (wingless-related integration site) signaling, matrix remodeling, coagulation, and angiogenesis. Overexpression of several proatherogenic transcripts, including IL1β, CCL2 (MCP-1), and IL6, were confirmed by quantitative polymerase chain reaction and significantly bolstered in coronary artery disease subjects. Angiographic coronary artery disease burden quantified by the Gensini score positively correlated with the expression of inflammatory genes in PVAT. Moreover, periaortic adipose inflammation was markedly higher in obese subjects with striking upregulation (≈8-fold) of IL1β expression compared to nonobese individuals.

CONCLUSIONS

Proatherogenic mediators that originate from dysfunctional PVAT may contribute to vascular disease mechanisms in human vessels. Moreover, PVAT may adopt detrimental properties under obese conditions that play a key role in the pathophysiology of ischemic heart disease. Graphic Abstract: A graphic abstract is available for this article.

The role of insulin resistance in the relation of visceral, abdominal subcutaneous and total body fat to cardiovascular function

BACKGROUND AND AIMS

The separate cardiovascular effects of type 2 diabetes and adiposity remain to be examined. This study aimed to investigate the role of insulin resistance in the relations of visceral (VAT), abdominal subcutaneous (aSAT) adipose tissue and total body fat (TBF) to cardiovascular remodeling.

METHODS AND RESULTS

In this cross-sectional analysis of the population-based Netherlands Epidemiology of Obesity study, 914 middle-aged individuals (46% men) were included. Participants underwent magnetic resonance imaging. Standardized linear regression coefficients (95%CI) were calculated, adjusted for potential confounding factors. All fat depots and insulin resistance (HOMA-IR), separate from VAT and TBF, were associated with lower mitral early and late peak filling rate ratios (E/A): -0.04 (-0.09;0.01) per SD (54 cm²) VAT; -0.05 (-0.10;0.00) per SD (94 cm²) aSAT; -0.09 (-0.16;-0.02) per SD (8%) TBF; -0.11 (-0.17;-0.05) per 10-fold increase in HOMA-IR, whereas VAT and TBF were differently associated with left ventricular (LV) end-diastolic volume: -8.9 (-11.7;-6.1) mL per SD VAT; +5.4 (1.1;9.7) mL per SD TBF. After adding HOMA-IR to the model to evaluate the mediating role of insulin resistance, change in E/A was -0.02 (-0.07;0.04) per SD VAT; -0.03 (-0.08;0.02) per SD aSAT; -0.06 (-0.13;0.01) per SD TBF, and change in LV end-diastolic volume was -7.0 (-9.7;-4.3) mL per SD VAT. In women, adiposity but not HOMA-IR was related to higher aortic arch pulse wave velocity.

CONCLUSION

Insulin resistance was associated with reduced diastolic function, separately from VAT and TBF, and partly mediated the associations between adiposity depots and lower diastolic function.

Maternal separation-induced increases in vascular stiffness are independent of circulating angiotensinogen levels

The renin-angiotensin system (RAS) precursor angiotensinogen (AGT) has been implicated in the functional and mechanical alterations of the vascular wall in response to high-fat diet (HFD). Previously, we showed that HFD exacerbates angiotensin II-induced constriction in isolated aortic rings from male rats exposed to maternal separation (MatSep), a model of early-life stress. Thus, the aim of this study was to investigate whether MatSep increases AGT secretion promoting vascular stiffness in rats fed a HFD. Male Wistar-Kyoto MatSep offspring were separated (3 h/day, postnatal days 2-14), and undisturbed littermates were used as controls. At weaning, rats were fed for 17 wk a normal diet (ND) or a HFD, 18% or 60% kcal from fat, respectively. In plasma, there was a main effect of MatSep reducing AGT concentration (P < 0.05) but no effect due to diet. In urine, ND-fed MatSep rats displayed higher AGT concentrations that were further increased by HFD (P < 0.05 vs. control). AGT mRNA abundance and protein expression were increased in adipose tissue from HFD-fed MatSep rats compared with control rats (P < 0.05). No significant differences in liver and kidney AGT levels were found between groups. In addition, MatSep augmented vascular stiffness assessed on freshly isolated aortic rings from ND-fed rats (P < 0.05), yet HFD did not worsen vascular stiffness in either MatSep or control rats. There was no correlation between plasma AGT and vascular stiffness in ND-fed rats; however, this relationship was negative in HFD-fed MatSep rats only (P < 0.05). Therefore, this study shows that MatSep-induced increases in vascular stiffness are independent of diet or plasma AGT.NEW & NOTEWORTHY This study demonstrates that there was no correlation between circulating levels of angiotensinogen (AGT) and the development of vascular stiffness in rats exposed to early-life stress and fed a normal diet. This study also shows that early-life stress-induced hypersensitive vascular contractility to angiotensin II in rats fed a high-fat diet is independent of circulating levels of AGT and occurs without further progression of vascular stiffness. Our data show that early-life stress primes the adipose tissue to secrete AGT in a sex- and species-independent fashion.

Perivascular Adipocytes in Vascular Disease

Perivascular adipocytes residing in the vascular adventitia are recognized as distinct endocrine cells capable of responding to inflammatory stimuli and communicating with the sympathetic nervous system and adjacent blood vessel cells, thereby releasing adipocytokines and other signaling mediators to maintain vascular homeostasis. Perivascular adipocytes exhibit phenotypic heterogeneity (both white and brown adipocytes) and become dysfunctional in conditions, such as diet-induced obesity, thus promoting vascular inflammation, vasoconstriction, and smooth muscle cell proliferation to potentially contribute to the development of vascular diseases, such as atherosclerosis, hypertension, and aortic aneurysms. Although accumulating data have advanced our understanding of the role of perivascular adipocytes in modulating vascular function, their impact on vascular disease, particularly in humans, remains to be fully defined. This brief review will discuss the mechanisms whereby perivascular adipocytes regulate vascular disease, with a particular emphasis on recent findings and current limitations in the field of research.

Human Perivascular Adipose Tissue as a Regulator of the Vascular Microenvironment and Diseases of the Coronary Artery and Aorta

Perivascular adipose tissue (PVAT) is an adipose depot that surrounds blood vessels in the human body and exerts local paracrine signaling. Under physiologically healthy conditions, PVAT has an anti-contractile effect on vessels, but in obesity this effect is lost. During metabolic disease, adiponectin secretion is dysregulated, influencing nitric oxide bioavailability and macrophage infiltration and inflammation, all of which mediate PVAT signaling. However, based on the location in the body, and the type of adipocyte present, PVAT has different relationships with risk factors for disease. Imaging studies in patients with cardiovascular disease have demonstrated important associations between PVAT structure and pathology, yet insight into molecular pathways regulating human PVAT function are still lacking. This review focuses on our current understanding of human PVAT and its secretory role in the vascular microenvironment. A current area of priority is defining molecular differences in the secretome between PVAT depots, as this could inform the treatment of diseases that occur in anatomically restricted locations. In addition, understanding progressive changes in PVAT structure and function during metabolic disease is required for effective targeted therapies.

Saxagliptin Prevents Increased Coronary Vascular Stiffness in Aortic-Banded Mini Swine

Increased peripheral conduit artery stiffness has been shown in patients with heart failure (HF) with preserved ejection fraction. However, it is unknown whether this phenomenon extends to the coronary vasculature. HF with preserved ejection fraction may be driven, in part, by coronary inflammation, and inhibition of the enzyme DPP-4 (dipeptidyl-peptidase 4) reduces inflammation and oxidative stress. The purpose of this study was to determine the effect of saxagliptin-a DPP-4 inhibitor-on coronary stiffness in aortic-banded mini swine. We hypothesized saxagliptin would prevent increased coronary artery stiffness in a translational swine model with cardiac features of HF with preserved ejection fraction by inhibiting perivascular adipose tissue inflammation. Yucatan mini swine were divided into 3 groups: control, aortic-banded untreated HF, and aortic-banded saxagliptin-treated HF. Ex vivo mechanical testing was performed on the left circumflex and right coronary arteries, and advanced glycation end product, NF-κB (nuclear factor-κB), and nitrotyrosine levels were measured. An increase in the coronary elastic modulus of HF animals was associated with increased vascular advanced glycation end products, NF-κB, and nitrotyrosine levels compared with control and prevented by saxagliptin treatment. Aortas from healthy mice were treated with media from swine perivascular adipose tissue culture to assess its role on vascular stiffening. Conditioned media from HF and saxagliptin-treated HF animals increased mouse aortic stiffness; however, only perivascular adipose tissue from the HF group showed increased advanced glycation end products and NF-κB levels. In conclusion, our data show increased coronary conduit vascular stiffness was prevented by saxagliptin and associated with decreased advanced glycation end products, NF-κB, and nitrotyrosine levels in a swine model with potential relevance to HF with preserved ejection fraction.

Removal of interscapular brown adipose tissue increases aortic stiffness despite normal systemic glucose metabolism in mice

Brown adipose tissue (BAT) is considered protective against obesity and related cardiometabolic dysfunction. Indeed, activation of BAT improves glucose homeostasis and attenuates cardiovascular disease development. However, whether a reduction in BAT mass perturbs metabolic function and increases risk for cardiovascular disease remains largely unknown. To address this question, C57BL/6J male mice underwent a sham procedure or surgical bilateral excision of interscapular BAT (iBATx) and were fed a normal chow or a Western diet for 18 wk, creating four groups ( n = 10/group). Mice were housed at 25°C. As expected, the Western diet increased final body weight and adiposity; however, contrary to our hypothesis, iBATx did not potentiate adiposity independent of diet. Furthermore, iBATx did not affect indexes of glycemic control (HbA1c, fasting glucose and insulin, and glucose area under the curve during a glucose tolerance test) and produced minimal-to-no effects on lipid homeostasis. The absence of metabolic disturbances with iBATx was not attributed to regrowth of iBAT or a "browning" or proliferative compensatory response of other BAT depots. Notably, iBATx caused an increase in aortic stiffness in normal chow-fed mice only, which was associated with an increase in aortic uncoupling protein-1. Collectively, we demonstrated that, at 25°C (i.e., limited thermal stress conditions), a substantial reduction in BAT mass via iBATx does not disrupt systemic glucose metabolism, challenging the current dogma that preservation of BAT is obligatory for optimal metabolic function. However, iBATx caused aortic stiffening in lean mice, hence supporting the existence of an interplay between iBAT and aortic stiffness, independent of alterations in glucose homeostasis.

Thermogenic capacity of human periaortic adipose tissue is transformed by body weight

The anatomical location of adipose tissue might have direct implications for its functionality and risk of cardiovascular disease. Adipose tissue surrounding blood vessels may be thermogenically more active in specific areas of the body, releasing substances that regulate vascular metabolism. In humans, the phenotypic characteristics of adipose tissue surrounding the aorta and the cardiovascular disease risk that it might entail remain largely unknown. Here, we compared thermogenesis-related molecular features of human periaortic adipose tissue samples with those of subcutaneous adipose tissue, obtained by sternotomy from 42 patients undergoing cardiovascular surgery. To determine the expression of genes related to energy expenditure and the levels of some adipokines, histological examinations, quantitative PCR, and protein expression measurements in adipocyte precursor cells were performed. Periaortic adipocytes were smaller than those from subcutaneous tissue. Moreover, weight gain induced periaortic adipocyte hypertrophy (r = -0.91, p<0.01). Compared to subcutaneous tissue, adiponectin, FABP4, IL-4 and IL-6 was decreased in periaortic adipocytes, whereas FGF21, UCP-1, PGC-1a, CITED1, Omentin and TFAM (Mitochondrial protein) increased. Upon analyzing patients’ clinical conditions, it emerged that the levels of PGC-1a both in male (r = -0.48 p<0.04) and female (r = -0.61, p<0.05) and TFAM in male (r = -0.72, p<0.0008) and female (r = -0.86, p<0.002) decreased significantly with progressive weight gain. However, no differences were observed in patients with diabetes mellitus 2 or Hyperlipidemia. Adipocytes surrounding the ascending aorta present markers of major thermogenic activity than those in subcutaneous tissue. Nevertheless, this characteristic might change, due to unfavorable metabolic conditions such as obesity, which is a risk factor for cardiovascular disease.

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.

The Role of Perivascular Adipose Tissue in Non-atherosclerotic Vascular Disease

Perivascular adipose tissue (PVAT) surrounds most large blood vessels and plays an important role in vascular homeostasis. PVAT releases various chemokines and adipocytokines, functioning in an endocrine and paracrine manner to regulate vascular signaling and inflammation. Mounting evidence suggests that PVAT plays an important role in atherosclerosis and hypertension; however, the role of PVAT in non-atherosclerotic vascular diseases, including neointimal formation, aortic aneurysm, arterial stiffness and vasculitis, has received far less attention. Increasing evidence suggests that PVAT responds to mechanical endovascular injury and regulates the subsequent formation of neointima via factors that promote smooth muscle cell growth, adventitial inflammation and neovascularization. Circumstantial evidence also links PVAT to the pathogenesis of aortic aneurysms and vasculitic syndromes, such as Takayasu's arteritis, where infiltration and migration of inflammatory cells from PVAT into the vascular wall may play a contributory role. Moreover, in obesity, PVAT has been implicated to promote stiffness of elastic arteries via the production of reactive oxygen species. This review will discuss the growing body of data and mechanisms linking PVAT to the pathogenesis of non-atherosclerotic vascular diseases in experimental animal models and in humans.

Hesperidin reverses perivascular adipose-mediated aortic stiffness with aging

We tested the hypothesis that hesperidin would reverse age-related aortic stiffness, perivascular adipose (PVAT) mediated-arterial stiffening and PVAT advanced glycation end-products (AGE) accumulation. Aortic pulse wave velocity (aPWV) and intrinsic mechanical stiffness, two measures of arterial stiffness, were assessed in C57BL/6 mice that were young (6months), old (27-29months), or old treated with hesperidin for 4weeks. Old compared with young mice had increased aPWV (444±10 vs. 358±8cm/s, P<0.05) and mechanical stiffness (6506±369 vs. 3664±414kPa, P<0.05). In old mice hesperidin reduced both aPWV (331±38cm/s) and mechanical stiffness (4445±667kPa) to levels not different from young. Aortic segments from old animals cultured with (+) PVAT had greater mechanical stiffness compared to young (+) PVAT (6454±323 vs. 3575±440kPa, P<0.05) that was ameliorated in arteries from old hesperidin treated cultured (+) PVAT (2639±258kPa). Hesperidin also reversed the aging-related PVAT AGE accumulation (all, P<0.05). A 4-week treatment with the AGE inhibitor aminoguanidine reversed both the age-related increase in aPWV (390±7cm/s) and mechanical stiffness (3396±1072kPa), as well as mechanical stiffness in arteries cultured (+) PVAT (3292±716kPa) (all, P<0.05) to values not different from young. In conclusion, hesperidin ameliorates the age-related increase in aortic stiffness and the PVAT-mediated effects on arterial stiffening. Hesperidin also reversed PVAT AGE accumulation, where PVAT AGE were shown to promote aortic stiffness with aging.

The Associations between Various Ectopic Visceral Adiposity and Body Surface Electrocardiographic Alterations: Potential Differences between Local and Remote Systemic Effects

Background

The associations between pericardial adiposity and altered atrial conduction had been demonstrated. However, data comparing differential effects of various body sites visceral adiposity on atrial and ventricular electrocardiographic alterations remains largely unknown.

Methods and Results

We assessed both peri-cardial fat (PCF) and peri-aortic visceral adiposity (TAT) using dedicated computed tomography (CT) software (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA), with anthropometrics including body mass index (BMI) and biochemical data obtained. We further related PCF and TAT data to standardized 12-leads electrocardiogram (ECG), including P and QRS wave morphologies. Among 3,087 study subjects (mean age, 49.6 years; 28% women), we observed a linear association among greater visceral adiposity burden, leftward deviation of P and QRS axes, longer PR interval and widened QRS duration (all p<0.001). These associations became attenuated after accounting for BMI and baseline clinical co-variates, with greater PCF remained independently associated with prolonged QRS duration (β = 0.91 [95% CI: 0.52, 1.31] per 1-SD increase in PCF, p<0.001). Finally, both PCF and TAT showed incremental value in identifying abnormally high PR interval (>200ms, likelihood-ratio: 33.17 to 41.4 & 39.03 for PCF and TAT) and widened QRS duration (>100ms, likelihood-ratio: 55.67 to 65.4 & 61.94 for PCF and TAT, all X² p<0.05) when superimposed on age and BMI.

Conclusion

We show in our data greater visceral fat burden may have differential associations on several body surface electrocardiographic parameters. Compared to remote adiposity, those surrounding the heart tissue demonstrated greater influences on altered cardiac activation or conduction, indicating a possible local biological effect.

Epiaortic fat pad area: A novel index for the dimensions of the ascending aorta

We sought to investigate the possible association between the area of the epiaortic fat pad (EAFP) and dimensions of the ascending aorta. A total of 193 individuals underwent transthoracic echocardiography (TTE) prospectively. The area of the EAFP was traced anterior to the aortic root and correlated with the diameter of the aorta. The mean area of the EAFP was 5.16 ± 2.28 cm(2) Absolute and indexed dimensions of the ascending aorta had a significant correlation with the area of the EAFP (p <0.001 for all). In a multivariate linear regression model, age >65 (p <0.001), body mass index >30 kg/m(2) (p = 0.02) and a history of hyperlipidemia (p = 0.003) were identified as independent predictors of the area for EAFP. In conclusion, both the absolute and indexed diameters of the ascending aorta at the different segments that directly come into contact with the EAFP linearly correlate with the area of the EAFP measured by TTE.

Perivascular adipose tissue, inflammation and insulin resistance: link to vascular dysfunction and cardiovascular disease

Obesity is a leading risk factor for the development of type 2 diabetes mellitus (DM2) and cardiovascular disease (CVD), however the underlying mechanisms still remain to be fully uncovered. It is now well accepted that dysfunctional adipose tissue in conditions of obesity is a critical source of inflammation that impacts the cardiovascular system and contributes to CVD. Although traditionally visceral adipose tissue has been linked to increased CVD risk, there is mounting interest in the role that fat accumulation around the vasculature plays in the pathogenesis of vascular dysfunction. Perivascular adipose tissue (PVAT) is in intimate contact with large, medium and small diameter arterial beds in several tissues, and has been shown to control vascular function as well as remodeling. PVAT does not merely mirror visceral adipose tissue changes seen in obesity, but has unique features that impact vascular biology. In lean individuals PVAT exerts vasodilatory and anti-inflammatory functions, however obesity results in PVAT inflammation, characterized by imbalance between pro- and anti-inflammatory cells as wells as adipokines. PVAT inflammation promotes insulin resistance in the vasculature, thus resulting in impaired insulin-mediated vasodilatory responses and vascular remodeling. In this review we address current knowledge about the mechanisms that link PVAT inflammation to insulin resistance and vascular dysfunction. Indeed, PVAT emerges as a novel type of adipose tissue that participates in the pathogenesis of CVD, independently to a large extent to visceral adipose tissue.

The association among peri-aortic root adipose tissue, metabolic derangements and burden of atherosclerosis in asymptomatic population

AIM

To describe the relationship between a novel measurement of peri-arotic root fat and ultrasound measures of carotid artery remodeling.

MATERIALS AND METHODS

We studied 1492 consecutive subjects (mean age: 51.04 ± 8.97 years, 27% females) who underwent an annual cardiovascular risk survey in Taiwan. Peri-aortic root fat (PARF) was assessed by cardiac CT using three-dimensional (3D) volume assessment. Carotid artery morphology and remodeling were assessed by ultrasound. We explored the relationships between PARF volumes, cardiometabolic risk profiles and carotid morphology and remodeling.

RESULTS

Mean PARF volume in current study was 20.8 ± 10.6 ml. PARF was positively correlated with measures of general adiposity, systemic inflammation, and several traditional cardiometabolic risk profiles (all p < 0.001) and successfully predicted metabolic syndrome (MetS) (AUROC: 0.75, 95%, confidence interval: 0.72-0.77). Higher PARF was independently associated with increased carotid artery intima-media thickness (IMT) (β-coef.: 0.08) and diameter (β-coef.: 0.08, both p < 0.05) after accounting for age, sex, BMI and other cardiovascular risk factors. The addition of PARF beyond metabolic syndrome components significantly provided incremental prediction value for abnormal IMT (ΔAUROC: 0.053, p = 0.0021).

CONCLUSION

Peri-aortic root fat is associated with carotid IMT, even after adjustment for cardiometabolic risks, age and coronary atherosclerosis. Further research studies are warranted to identify the mediators of downstream pathophysiologic effects on carotid arteries by PARF and understand the mechanisms related to this correlation.

The role of perivascular adipose tissue in vasoconstriction, arterial stiffness, and aneurysm

Since the "rediscovery" of brown adipose tissue in adult humans, significant scientific efforts are being pursued to identify the molecular mechanisms to promote a phenotypic change of white adipocytes into brown-like cells, a process called "browning". It is well documented that white adipose tissue (WAT) mass and factors released from WAT influence the vascular function and positively correlate with cardiac arrest, stroke, and other cardiovascular complications. Similar to other fat depots, perivascular adipose tissue (PVAT) is an active endocrine organ and anatomically surrounds vessels. Both brown-like and white-like PVAT secrete various adipokines, cytokines, and growth factors that either prevent or promote the development of cardiovascular diseases (CVDs) depending on the relative abundance of each type and their bioactivity in the neighboring vasculature. Notably, pathophysiological conditions, such as obesity, hypertension, or diabetes, induce the imbalance of PVAT-derived vasoactive products that promote the infiltration of inflammatory cells. This then triggers derangements in vascular smooth muscle cells and endothelial cell dysfunction, resulting in the development of vascular diseases. In this review, we discuss the recent advances on the contribution of PVAT in CVDs. Specifically, we summarize the current proposed roles of PVAT in relationship with vascular contractility, endothelial dysfunction, neointimal formation, arterial stiffness, and aneurysm.

Myocardial fat as a part of cardiac visceral adipose tissue: physiological and pathophysiological view

Thoracic fat includes extra-pericardial (outside the visceral pericardium) and intra-pericardial (inside the visceral pericardium) adipose tissue. It is called ectopic adipose tissue although it is a normal anatomical structure. Intra-pericardial adipose tissue, which is predominantly composed of epicardial and pericoronary adipose tissue, has a significant role in cardiovascular system function. It provides metabolic-mechanical support to the heart and blood vessels in physiological conditions, while it represents metabolic-cardiovascular risk in case of qualitative and quantitative structural changes in the tissue: it correlates with coronary atherosclerotic disease, left ventricular mass, left atrium enlargement and atrial fibrillation presence. In the last decade there has been mounting evidence of fat cells presence in the myocardium of healthy (non-diseased) persons as well as in persons with both cardiovascular and non-cardiovascular diseases. Thus, it is necessary to clarify the incidence, aetiology, physiological role of fat cells in the myocardium, as well as the clinical significance of pathological fatty infiltration of the myocardium.

The relationship of periaortic fat thickness and cardiovascular risk factors in children with Turner syndrome

Children with Turner syndrome (TS) have a broad range of later health problems, including an increased risk of cardiovascular morbidity and mortality. The aim of this study was to evaluate the relationship between periaortic fat thickness (PAFT) and metabolic and cardiovascular profiles in children with TS. Twenty-nine TS and 29 healthy children and adolescents were enrolled in the study. Anthropometric measurements, pubertal staging, and blood pressure measurements were performed. Fasting serum glucose, insulin, and lipid profile were measured. Periaortic fat thickness was measured using an echocardiography method, which has not previously been applied in children with TS. No difference was found between TS and control subject (CS) in age, weight, waist/hip ratio, HDL cholesterol and LDL cholesterol levels. However, in TS subjects, total cholesterol (p = 0.045) was greater than that in controls. It was determined that 13.7 % (N: 4) of TS subjects had dyslipidemia. Mean fasting glucose, fasting insulin, QUICK-I, HOMA, and FGIR index were similar in TS and in CS, whereas 17.2 % (N: 5) of TS subjects had insulin resistance (IR) and 13.7 % (N: 4) had impaired glucose tolerance. Six subjects (20.6 %) were diagnosed as hypertensive. Periaortic fat thickness was significantly higher in the TS group (p < 0.001) (0.1694 ± 0.025 mm in the TS group and 0.1416 ± 0.014 mm in the CS group) In children with TS, PAFT was positively correlated with fasting insulin, body mass index, and diastolic blood pressure. Our results provide additional evidence for the presence of subclinical cardiovascular disease in TS. In addition to existing methods, we recommend the measurement of periaortic fat thickness in children with TS to reveal the presence of early atherosclerosis.

Aortic perivascular adipose-derived interleukin-6 contributes to arterial stiffness in low-density lipoprotein receptor deficient mice

We tested the hypothesis that aortic perivascular adipose tissue (PVAT) from young low-density lipoprotein receptor-deficient (LDLr(-/-)) mice promotes aortic stiffness and remodeling, which would be mediated by greater PVAT-derived IL-6 secretion. Arterial stiffness was assessed by aortic pulse wave velocity and with ex vivo intrinsic mechanical properties testing in young (4-6 mo old) wild-type (WT) and LDLr(-/-) chow-fed mice. Compared with WT mice, LDLr(-/-) mice had increased aortic pulse wave velocity (407 ± 18 vs. 353 ± 13 cm/s) and intrinsic mechanical stiffness (5,308 ± 623 vs. 3,355 ± 330 kPa) that was associated with greater aortic protein expression of collagen type I and advanced glycation end products (all P < 0.05 vs. WT mice). Aortic segments from LDLr(-/-) compared with WT mice cultured in the presence of PVAT had greater intrinsic mechanical stiffness (6,092 ± 480 vs. 3,710 ± 316 kPa), and this was reversed in LDLr(-/-) mouse arteries cultured without PVAT (3,473 ± 577 kPa, both P < 0.05). Collagen type I and advanced glycation end products were increased in LDLr(-/-) mouse arteries cultured with PVAT (P < 0.05 vs. WT mouse arteries), which was attenuated when arteries were cultured in the absence of PVAT (P < 0.05). PVAT from LDLr(-/-) mice secreted larger amounts of IL-6 (3.4 ± 0.1 vs. 2.3 ± 0.7 ng/ml, P < 0.05), and IL-6 neutralizing antibody decreased intrinsic mechanical stiffness in LDLr(-/-) aortic segments cultured with PVAT (P < 0.05). Collectively, these data provide evidence for a role of PVAT-derived IL-6 in the pathogenesis of aortic stiffness and remodeling in chow-fed LDLr(-/-) mice.

Thoracic periaortic adipose tissue is increased in patients with subclinical hypothyroidism

OBJECTIVE

To evaluate thoracic periaortic adipose tissue (TAT) volume in patients with subclinical hypothyroidism (SH) in comparison with controls and in relation to cardiovascular risk factors.

METHODS

The study population consisted of 28 newly diagnosed SH patients (mean (s.d.) age: 37.3 (±11.4) years, 85.7% were females) and 37 healthy volunteers (mean (s.d.) age: 35.3 (±10.7) years, 81.5% were females). Comparisons between patient and control groups used demographic characteristics, anthropometrics, and laboratory findings. All participants underwent thoracic radiographic assessment in the supine position, using an eight-slice multidetector computed tomography scanner and TAT volume was measured.

RESULTS

The TAT volume was determined to be 27.2 (±12.7) cm(3) in the SH group and 16.3 (±8.1) cm(3) in the control group, and the difference was statistically significant (P<0.001). In addition, TSH levels were significantly higher in the patient group compared with the control group (P<0.001). A significant correlation was also found between TSH levels and TAT volume (r=0.572; P<0.001). In SH patients, no significant difference was noted in TAT levels with respect to sex (P=0.383) or concomitant smoking status (P=0.426).

CONCLUSIONS

Our findings indicate that SH patients have significantly higher TAT values than controls and that increased TAT levels correlate with increased TSH levels.

Influence of body fatness distribution and total lean mass on aortic stiffness in nonobese individuals

BACKGROUND

Subjects with normal body mass index but high body fat percentage have higher cardiovascular risk than subjects with normal weight and low fat mass. However, the association of fat distribution and lean mass with carotid-femoral pulse wave velocity (cfPWV) among nonobese apparently healthy individuals has never been assessed.

METHODS

In 136 nonobese volunteers (mean age = 45±9 years; 57% women) without manifest cardiovascular disease, cfPWV was measured by applanation tonometry. Fat and lean mass were measured by dual-energy x-ray absorptiometry.

RESULTS

In univariate analysis, total fat (r = 0.17; P < 0.01), trunk fat (r = 0.27; P < 0.01), and trunk/total fat ratio (r = 0.32; P < 0.01) were correlated with cfPWV. After adjustment for age and mean arterial pressure, only central fat distribution (trunk/total fat ratio) was significantly associated with cfPWV. In the fully adjustment model, there was a significant interaction between fat distribution and lean mass. When the study sample was grouped by fat distribution and total lean mass medians, subjects with central fat distribution and low lean mass (group 4) had higher log-transformed cfPWV than the noncentral fat/low lean mass group (group 2) (0.89, 95% confidence interval (CI) = 0.86-0.92 vs. 0.85, 95% CI = 0.83-0.87; P < 0.01) or the noncentral fat/high lean mass group (group 1) (0.89, 95% CI = 0.86-0.92 vs. 0.84, 95% CI = 0.81-0.87; P < 0.01) after adjustments. Aortic stiffness increased from group 1 to group 4 (P for linear trend < 0.001).

CONCLUSIONS

Among normal weight individuals without manifest cardiovascular disease, the combination of central fat distribution and low lean mass is associated with higher cfPWV. These factors are more closely related to cfPWV than total fat mass.

Thoracic periaortic adipose tissue in relation to cardiovascular risk in type 2 diabetes mellitus

OBJECTIVE

To evaluate thoracic periaortic adipose tissue (TAT) burden in patients with type 2 diabetes mellitus (DM) in comparison with controls and in relation to cardiovascular risk factors.

METHODS

A total of 93 patients with type 2 DM (mean (standard deviation; SD) age: 56.7 (11.2) years, 71.0 % were men) and 85 nondiabetic control subjects (mean (SD) age: 54.6 (10.9) years, 58.8 % were men) who were admitted to Mevlana University hospital between January 2011 and June 2013 and underwent multidetector computed tomography for any reason were included in this retrospective cohort study. Patient and control groups were compared in terms of demographic characteristics, anthropometrics, and laboratory findings. TAT volume was evaluated in both groups, while correlates of TAT were determined via linear regression analysis among patients.

RESULTS

In patients with type 2 DM, TAT volume (40.1 (23.9) versus 16.9 (7.7) cm(3), p < 0.001), fasting blood glucose (p < 0.001), total cholesterol (p < 0.001), triglyceride (p = 0.017), and low-density lipoprotein (LDL) cholesterol (p = 0.034) levels were significantly higher compared with the control group. Strong positive correlation of TAT was noted with body mass index (r = 0.339, p = 0.001) and serum levels for fasting blood glucose (r = 0.343, p < 0.001), hemoglobin A1c (HbA1c; r = 0.615, p < 0.001), total cholesterol (r = 0.269, p = 0.009), and LDL cholesterol (r = 0.258, p = 0.013). In stepwise regression analysis, Hba1c emerged as a significant predictor of TAT (b = 0.610, p < 0.001), contributing to 19 % of its variability.

CONCLUSION

In conclusion, our findings indicate significantly higher values for TAT in diabetics than controls, being associated positively with body weight, poor glycemic control, and dyslipidemia and strongly predicted by HbA1c levels in diabetic patients, while not differing with respect to gender, smoking status, and concomitant hypertension.

Periaortic fat and cardiovascular risk: a comparison of high-risk older adults and age-matched healthy controls

Objective

Fat accumulation around the heart and aorta may impact cardiovascular (CV) health. The purpose of this study was to conduct a systematic investigation to examine potential associations of these fat depots with risk factors for CV events, which has not been done before.

Methods

Pericardial fat, periaortic fat around the ascending aorta (AA), descending aorta (DA) and aortic arch, and abdominal subcutaneous and visceral fat were measured by MRI in older adults with (n=385, 69±8 years, 52% female) and without (n=50, 69±8 years, 58% female) risk factors for a CV event.

Results

Individuals with CV risk factors exhibited greater fat volumes across all fat depots compared to those without risk factors. In analysis of covariance accounting for age, gender, race/ethnicity, diabetes, hypertension, coronary artery disease, smoking, and BMI, individuals with risk factors possessed higher epicardial, pericardial, AA, DA, and abdominal visceral fat (p<0.05). When matched one-to-one on age, gender, race/ethnicity, and BMI, AA and DA fat were higher in those with versus without CV risk factors (p<0.01).

Conclusions

Older adults with a high risk for CV events have greater periaortic fat than low-risk adults, even after accounting for BMI. More studies are needed to determine whether greater periaortic fat predicts future CV events.