Predominance of Abdominal Visceral Adipose Tissue Reflects the Presence of Aortic Valve Calcification

Association of Anthropometric and CT-Based Obesity Indices with Subclinical Atherosclerosis

AIM

Few studies have compared the strength in the associations of anthropometric and computed tomography (CT)-based obesity indices with coronary artery calcification (CAC), aortic artery calcification (AoAC), and aortic valve calcification (AVC).

METHODS

We assessed cross-sectcional associations of anthropometric and CT-based obesity indices with CAC, AoAC, and AVC. Anthropometric measures included body mass index (BMI), waist circumference, hip ircumference, waist-to-hip circumference ratio, and waist-to-height ratio in 931 men (mean age, 63.7 years) from a population-based cohort. CT images at the L4/5 level were obtained to calculate the areas of abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), total adipose tissue (TAT), VAT-to-SAT ratio (VSR), and VAT-to-TAT ratio (VTR). CAC, AoAC, and AVC were quantified using the Agatston score based on CT scanning.

RESULTS

CAC, AVC, and AoAC were present in 348 (62.6%), 173 (18.6%), and 769 (82.6%) participants, respectively. In multivariable models adjusting for age, lifestyle factors, and CT types (electron beam CT and multidetector row CT), anthropometric and CT-based obesity indices were positively associated with CAC (p＜0.01). Conversely, VAT-to-SAT ratio and VAT-to-TAT ratio were positively associated with AoAC (p＜0.01). Any obesity indices were not associated with AVC.

CONCLUSIONS

The strength of the associations of obesity indices with subclinical atherosclerosis varied according to the anatomically distinct atherosclerotic lesions, among men.

Exploring the significance of epicardial adipose tissue in aortic valve stenosis and left ventricular remodeling: Unveiling novel therapeutic and prognostic markers of disease

Aortic stenosis (AS) is a dynamic degenerative process that shares many pathophysiological features with atherogenesis, from initial proinflammatory calcification and focal thickening of the valve leaflets to obstruction of left ventricular outflow due to superimposed of severe calcification and immobilization of the valve leaflets. As the prevalence increases with age, AS is expected to become one of the most common heart diseases worldwide. In both obese and nonobese patients, persistent thickening of epicardial adipose tissue (EAT) is associated with a shift in its normal metabolic functions toward a dysmetabolic and proatherogenic phenotype that may impair the physiology of adjacent coronary arteries and promote the occurrence of coronary atherosclerosis. In tight analogy with atherosclerosis, recent clinical evidence indicates that EAT may also exert a deleterious role in promoting AS and contributing to myocardial dysfunction, leading to increased health risk for elderly patients with AS and an economic burden on the health care system. This review discusses the clinical and pathologic evidence for the association between EAT and AS and concomitant left ventricular hypertrophy, and provides new insights for the future direction of AS diagnosis and treatment.

Cardiac valve calcification in patients on maintenance dialysis. The role of malnutrition-inflammation syndrome, adiposity andcomponents of sarcopenia. A cross-sectional study

BACKGROUND & AIMS

Cardiac valve calcification (CVC) is a predictor of cardiovascular disease and all-cause mortality in end stage kidney disease (ESKD) patients. Several risk factors are related to CVC in patients with ESKD including traditional ones as well as inflammation, bone mineral disease and malnutrition. Adiposity is associated with dyslipidemia and proinflammatory activity which could predispose for CVC. Sarcopenia or dynapenia is a state common in patients with ESKD. This study aimed to investigate the relationship of adiposity, sarcopenia and malnutrition-inflammation markers with CVC in patients on maintenance hemodialysis.

METHODS

CVC in aortic (AVC), mitral valves (MVC) and systolic and diastolic dysfunction (DD) were assessed by using two-dimensional echocardiography. Nutritional, adiposity and anthropometric assessments were made using several indices respectively. Creatinine index and muscle strength measurements were also performed. Biochemical parameters such as total proteins, albumin, calcium, phosphate, plasma lipoproteins, C-Reactive Protein and parathyroid hormone were also measured.

RESULTS

Adiposity, nutritional, and sarcopenia parameters did not show any difference between patients with or without CVC. Age ≥ 65 years [PR: 1.47 p = 0.012], DD [PR: 2.31, p = 0.005], high CRP/albumin ratio [PR: 1.46, p = 0.01], mid arm circumference (MAC) < 26 cm [PR: 1.37, p = 0.03] were associated with increased prevalence of AVC, while DD [PR: 1.97 p = 0.02], high CRP/albumin ratio [PR: 1.56, p = 0.02], and MAC < 26 cm [PR: 1.52, p = 0.01], showed positive correlation with MVC. Age ≥ 65 years [PR: 1.33, p = 0.028], DD [PR: 1.72, p = 0.01], high CRP/albumin ratio [PR: 1.53, p = 0.003], and MAC < 26 cm [PR: 1.4, p = 0.006], related to greater prevalence of calcification at any valve.

CONCLUSIONS

Ageing, diastolic dysfunction, MAC and increased CRP/albumin ratio were powerful predictors of CVC in patients on hemodialysis.

Inflammation and Cardiovascular Diseases in the Elderly: The Role of Epicardial Adipose Tissue

Human aging is a complex phenomenon characterized by a wide spectrum of biological changes which impact on behavioral and social aspects. Age-related changes are accompanied by a decline in biological function and increased vulnerability leading to frailty, thereby advanced age is identified among the major risk factors of the main chronic human diseases. Aging is characterized by a state of chronic low-grade inflammation, also referred as inflammaging. It recognizes a multifactorial pathogenesis with a prominent role of the innate immune system activation, resulting in tissue degeneration and contributing to adverse outcomes. It is widely recognized that inflammation plays a central role in the development and progression of numerous chronic and cardiovascular diseases. In particular, low-grade inflammation, through an increased risk of atherosclerosis and insulin resistance, promote cardiovascular diseases in the elderly. Low-grade inflammation is also promoted by visceral adiposity, whose accumulation is paralleled by an increased inflammatory status. Aging is associated to increase in epicardial adipose tissue (EAT), the visceral fat depot of the heart. Structural and functional changes in EAT have been shown to be associated with several heart diseases, including coronary artery disease, aortic stenosis, atrial fibrillation, and heart failure. EAT increase is associated with a greater production and secretion of pro-inflammatory mediators and neuro-hormones, so that thickened EAT can pathologically influence, in a paracrine and vasocrine manner, the structure and function of the heart and is associated to a worse cardiovascular outcome. In this review, we will discuss the evidence underlying the interplay between inflammaging, EAT accumulation and cardiovascular diseases. We will examine and discuss the importance of EAT quantification, its characteristics and changes with age and its clinical implication.

Metformin alleviates stress-induced cellular senescence of aging human adipose stromal cells and the ensuing adipocyte dysfunction

Aging is associated with central fat redistribution and insulin resistance. To identify age-related adipose features, we evaluated the senescence and adipogenic potential of adipose-derived stromal cells (ASCs) from abdominal subcutaneous fat obtained from healthy normal-weight young (<25 years) or older women (>60 years). Increased cell passages of young-donor ASCs (in vitro aging) resulted in senescence but not oxidative stress. ASC-derived adipocytes presented impaired adipogenesis but no early mitochondrial dysfunction. Conversely, aged-donor ASCs at early passages displayed oxidative stress and mild senescence. ASC-derived adipocytes exhibited oxidative stress, and early mitochondrial dysfunction but adipogenesis was preserved. In vitro aging of aged-donor ASCs resulted in further increased senescence, mitochondrial dysfunction, oxidative stress, and severe adipocyte dysfunction. When in vitro aged young-donor ASCs were treated with metformin, no alteration was alleviated. Conversely, metformin treatment of aged-donor ASCs decreased oxidative stress and mitochondrial dysfunction resulting in decreased senescence. Metformin's prevention of oxidative stress and of the resulting senescence improved the cells' adipogenic capacity and insulin sensitivity. This effect was mediated by the activation of AMP-activated protein kinase as revealed by its specific inhibition and activation. Overall, aging ASC-derived adipocytes presented impaired adipogenesis and insulin sensitivity. Targeting stress-induced senescence of ASCs with metformin may improve age-related adipose tissue dysfunction.

The role of inflammation and metabolic risk factors in the pathogenesis of calcific aortic valve stenosis

Given the epidemiologic increase of aged population in the world, aortic stenosis (AS) represents now the most common valvular heart disease in industrialized countries. It is a very challenging disease, representing an important cause of morbidity, hospitalization and death in the elderly population. It is widely recognized that AS is the result of a very complex active process, driven by inflammation and involving multifactorial pathological mechanisms promoting valvular calcification and valvular bone deposition. Several evidence suggest that epicardial adipose tissue (EAT), the visceral fat depot of the heart, represents a direct source of cytokines and could mediate the deleterious effects of systemic inflammation on the myocardium. Importantly, obesity and metabolic disorders are associated with chronic systemic inflammation leading to a significant increase of EAT amount and to a pro-inflammatory phenotypic shift of this fat depot. It has been hypothesized that the EAT inflammatory state can influence the structure and function of the heart, thus contributing to the pathogenesis of several cardiac diseases, including calcific AS. The current review will discuss the recently discovered mechanisms involved in the pathogenesis of AS, with particular attention to the role of inflammation, metabolic risk factors and pro-fibrotic and pro-osteogenic signal pathways promoting the onset and progression of the disease. Moreover, it will be explored the potential role of EAT in the AS pathophysiology.

Malnutrition as a risk factor for cardiac valve calcification in patients under maintenance dialysis: a cross-sectional study

PURPOSE

Cardiac valve calcification (CVC) is a significant risk factor for cardiovascular morbidity and mortality in patients with chronic kidney disease on maintenance hemodialysis. The aim of this study was to investigate the association of several risk factors and particularly of malnutrition on CVC.

METHODS

In this cross-sectional cohort study, we included stable adult patients on maintenance hemodialysis. Calcification of cardiac valves was evaluated using two-dimensional echocardiography. Nutritional assessment and body composition measurements were performed using the MQSGA clinical tool and bioelectrical impedance analysis, respectively. Biochemical parameters such as serum calcium, phosphorus, iPTH, 1.25 hydroxy-vitamin-D, triglycerides, total cholesterol, HDL-C, LDL-C, total proteins, albumin, creatinine and CRP were assessed as potentially risk factors. The receiver operating characteristic (ROC) curve analysis was used to evaluate the prognostic ability of the aforementioned variables on severe degree CVC. Binary logistic regression analysis was also performed to identify independent variables of severe CVC.

RESULTS

Overall, 42 patients were included in the study with half of them exhibiting mitral calcification, 38% aortic valve calcification, and 16.7% calcification in both valves. ROC analysis indicated that aging (p = 0.011), increased CRP (p = 0.038) and decreased value of serum albumin to total proteins ratio (p = 0.012) were positive prognostic factors for moderate to severe degree cardiac valve calcification. Low phase angle was also associated with CVC, although with moderate specificity.

CONCLUSION

Aging, inflammation, low serum albumin to total proteins ratio and low phase angle values as indicators of malnutrition are predictors of severe CVC in end-stage renal disease patients on hemodialysis.

Periaortic adipose tissue volume is associated with sclerotic changes in the adjacent aortic valve

Aortic sclerosis is associated with increased cardiovascular mortality and morbidity. Numerous studies have shown that visceral adiposity is associated with development of atherosclerosis, especially in the adjacent vascular wall. Considering the similar pathophysiology of aortic sclerosis and atherosclerosis, it can be hypothesized that visceral adipose tissue adjacent to aortic valve may be associated with aortic sclerosis. In this study, we investigated the relationship between periaortic adipose tissue volume and sclerotic changes in the adjacent aortic valve. In this retrospective study, 80 patients with a concurrent MSCT and echocardiography in the last 6 months were enrolled. Echocardiographic examinations were retrospectively evaluated regarding the presence of aortic sclerosis. Periaortic adipose tissue volume was calculated on a computer assisted work station (Leonardo Workstation, Siemens, Erlangen, Germany) by an experienced radiologist. Patient group (61.63 ± 8.55 years and 50% male) and the control group (61.45 ± 5.68 years, 50% male) each consisted 40 participants. Patient group had significantly higher BUN (42.50 (15.00-211.00) vs. 34.00 (12.00-107.00) mg/dL, p = 0.003), uric acid (5.40 (3.40-14.70) vs. 4.30 (2.30-6.70) ng/mL, p = 0.005) and LDL-C levels (121.50 (60.00-215.00) vs. 86.50 (49.00-209.00) mg/dL, p = 0.001) when compared to control group. Patient group had also significantly higher periaortic adipose tissue volume (32.45 (11.70-51.23) vs. 16.00 (6.29-32.96) ml, p < 0.001). Multivariate regression analysis revealed that periaortic adipose tissue volume was independently associated with the presence of aortic sclerosis (OR 0.241, 95% CI 0.143-0.946, p = 0.001). In this study, we demonstrated for the first time that periaortic adipose tissue volume was independently associated with the presence of sclerotic changes in the adjacent aortic valve.

Abdominal visceral adipose tissue is associated with unsuspected pulmonary embolism on routine CT scans in patients with gastrointestinal cancer

OBJECTIVE

Unsuspected pulmonary embolism (UPE) has been increasingly diagnosed as an incidental finding on CT scans for routine staging in cancer patients. Previous studies suggest that obesity is an independent risk factor for venous thromboembolism in patients with malignant tumors. In this study, we aimed to investigate the association between abdominal adipose tissue, especially visceral adipose tissue (VAT) and the occurrence of UPE in hospitalized patients with gastrointestinal cancer.

METHODS

Routine contrast-enhanced chest and abdominal CT scans of 1974 patients were retrospectively assessed for the presence of UPE, of which 58 patients were identified with UPE and 108 non-UPE patients were selected as the non-UPE control group based on several matching criteria. Abdominal adipose tissue was measured by volumes of VAT and subcutaneous adipose tissue (SAT) at the navel level.

RESULTS

VAT, SAT, indwelling venous catheters, surgery, chemotherapy, and bed rest or immobilization were associated with the occurrence of UPE. Higher VAT volumes were associated with increased risk of UPE (odds ratio: 1.96; 95% confidence interval: 1.25, 3.06; p = 0.003) adjusting body mass index (BMI), bed rest or immobilization, surgery, chemotherapy and smoking, while SAT was not associated with UPE adjusting the same confounders (p = 0.117). No statistical association was found between BMI and UPE (p = 0.102).

CONCLUSION

Higher VAT rather than SAT is associated with an increased risk of unsuspected pulmonary embolism on routine CT scans in hospitalized gastrointestinal cancer patients.

ADVANCES IN KNOWLEDGE

Our findings indicate that VAT is a stronger risk factor for unsuspected pulmonary embolism than BMI and SAT in hospitalized patients with gastrointestinal cancer.

Correlation between epicardial fat thickness and aortic valve sclerosis

Background

Epicardial fat is a true visceral fat deposit with adverse effects through the secretion of numerous proinflammatory and proatherogenic cytokines. Previous studies showed an association between aortic valve sclerosis and coronary artery disease. The aim of this study was to determine the correlation between epicardial fat thickness and aortic valve sclerosis.

Method

The study involved 225 patients who were admitted for coronary angiography due to new-onset angina. They underwent transthoracic echocardiography and epicardial fat thickness was determined. The sclerosis scoring of each aortic cusp, average aortic valve sclerosis score index, and left ventricular ejection fraction were determined. The variables of left ventricular diastolic function obtained included the early diastolic velocity determined by transmitral pulsed Doppler, and early mitral annular velocity measured by tissue Doppler.

Results

Patients with an epicardial fat thickness ≥7 mm were older ( p = 0.006), with more hypertension ( p = 0.045) and hyperlipidemia ( p < 0.001). Their average aortic valve sclerosis score index was higher (1.4 ± 1.02 vs. 0.86 ± 0.85, p = 0.001), and left ventricular ejection fraction and early mitral annular velocity were lower ( p < 0.001 and 0.03, respectively). They also exhibited more left ventricular hypertrophy ( p = 0.026) and a trend towards more significant coronary artery disease and 3-vessel disease ( p = 0.086 and 0.073, respectively).

Conclusion

Our findings confirm that epicardial fat as a marker of visceral adipose tissue may have an important role in promoting inflammatory and atherosclerotic changes in the aortic valve.