High pericardial and peri-aortic adipose tissue burden in pre-diabetic and diabetic subjects. BMC Cardiovasc Disord. 2013;13:98. [PMID: 24499326 PMCID: PMC3832227 DOI: 10.1186/1471-2261-13-98]

Biomarkers of insulin sensitivity/resistance

In recent years, remarkable advancements in elucidating the intricate molecular underpinnings of type 2 diabetes mellitus (T2D) have been achieved. Insulin resistance (IR) has been unequivocally acknowledged as the driving pathogenetic mechanism of T2D, preceding disease onset by several years. Nonetheless, diagnostic tools for ascertaining IR are lacking in current clinical practice, representing a critical unmet need; use of the hyperinsulinemic-euglycemic glucose clamp, widely accepted as the gold standard method for evaluating IR at present, is cumbersome in a clinical setting. Thus, the development of well-validated, reliable, and affordable biomarkers of IR has attracted considerable attention from the research community. The biomarkers under investigation can be divided into two major categories: (1) indices or ratios, comprising parameters obtained from a basic or comprehensive metabolic panel and/or derived from anthropometric measurements, and (2) circulating molecules implicated in pathophysiological processes associated with IR. Furthermore, numerous novel biomarkers, including markers of β-cell dysfunction, radiographic quantification of excess visceral adipose tissue, T2D prediction models, certain microRNAs and metabolomic biomarkers, have also provided promising preliminary results. This narrative review aims to present current evidence pertaining to the most notable and exciting biomarkers of IR that are under rigorous evaluation.

Determinants of echocardiographic epicardial adipose tissue in a general middle-aged population - The Cardiovascular Risk in Young Finns Study

Epicardial adipose tissue (EAT) is the cardiac visceral fat depot proposed to play a role in the etiology of various cardiovascular disease outcomes. Little is known about EAT determinants in a general population. We examined cardiometabolic, dietary, lifestyle and socioeconomic determinants of echocardiograpghically measured EAT in early adulthood. Data on cardiometabolic, dietary, lifestyle and socioeconomic factors were collected from participants of the Cardiovascular Risk in Young Finns Study (YFS; N = 1667; age 34-49 years). EAT thickness was measured from parasternal long axis echocardiograms. Multivariable regression analysis was used to study potential EAT determinants. Possible effect modification of sex was addressed. Mean EAT thickness was 4.07 mm (95% CI 4.00-4.17). Multivariable analysis [β indicating percentage of change in EAT(mm) per one unit increase in determinant variable] indicated female sex (β = 11.0, P < 0.0001), type 2 diabetes (β = 14.0, P = 0.02), waist circumference (cm) (β = 0.38, P < 0.0001), systolic blood pressure (mmHg) (β = 0.18, P = 0.02) and red meat intake (g/day) (β = 0.02, P = 0.05) as EAT determinants. Sex-specific analysis revealed age (year) (β = 0.59, P = 0.01), alcohol intake (drinks/day) (β = 4.69, P = 0.006), heavy drinking (yes/no) (β = 30.4, P < 0.0001) as EAT determinants in women and fruit intake (g/day) (β = -1.0, P = 0.04) in men. In the YFS cohort, waist circumference, systolic blood pressure and red meat intake were directly associated with EAT among all participants. In women, age, alcohol intake, heavy drinking and type 2 diabetes associated directly with EAT, while an inverse association was observed between fruit intake and EAT in men.

Relationship Between Perivascular Adipose Tissue and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis

We conducted a systematic review and meta-analysis aimed at estimating the association between perivascular adipose tissue (PVAT) and some of the cardiovascular risk factors. A systematic search was conducted from January 1980 up to and including 2022 to identify studies that examined the relationship between PVAT and cardiovascular risk factors as obesity and its indices, hypertension, lipids, and glucose intolerance/diabetes. The Medline and Embase databases were searched using the PubMed and Scopus. Data were extracted from 23 studies that fit the criteria. To conduct meta-analysis, we used an approximation of equating the method of correlating assessment because different authors used either Pearson or Spearman correlation. Interrelations of PVAT and body mass index were analyzed in eight studies. Most studies revealed reliable direct correlation; the results of the meta-analysis also showed a significant (P = 0.37, P < 0.01, n = 12,346) correlation. PVAT and waist circumference were analyzed in six studies. Meta-analysis on the selected sample (n = 10,947) showed a significant (r = 0.45, P < 0.01) correlation. Relationship between PVAT and hypertension was revealed in three studies. Direct correlations were found in all studies. Meta-analysis showed the reliability of the correlation dependence (r = 0.21, P < 0.01, n = 3996). PVAT and blood glucose was evaluated in three studies (n = 3689). In each study a reliable (P < 0.05) direct correlation was obtained. Meta-analysis showed a significant correlation of weak strength (r = 0.24, P < 0.01). We demonstrated significant positive correlations of PVAT with the levels of total cholesterol (r = 0.05, P < 0.01), low-density lipoprotein cholesterol (r = 0.13, P < 0.01), and triglycerides (r = 0.29, P < 0.01), and a negative relationship with high-density lipoprotein cholesterol (r = -0.18, P < 0.01) in this meta-analysis. Despite some limitations, the findings of this systematic review and meta-analysis confirmed that PVAT significantly correlates with studied cardiovascular risk factors. Because PVAT presents a great interest in terms of cardiovascular remodeling and cardiovascular disease, its assessment in patients with and without cardiovascular pathology needs further research.

Interplay of Angiotensin Peptides, Vasopressin, and Insulin in the Heart: Experimental and Clinical Evidence of Altered Interactions in Obesity and Diabetes Mellitus

The present review draws attention to the specific role of angiotensin peptides [angiotensin II (Ang II), angiotensin-(1-7) (Ang-(1-7)], vasopressin (AVP), and insulin in the regulation of the coronary blood flow and cardiac contractions. The interactions of angiotensin peptides, AVP, and insulin in the heart and in the brain are also discussed. The intracardiac production and the supply of angiotensin peptides and AVP from the systemic circulation enable their easy access to the coronary vessels and the cardiomyocytes. Coronary vessels and cardiomyocytes are furnished with AT1 receptors, AT2 receptors, Ang (1-7) receptors, vasopressin V1 receptors, and insulin receptor substrates. The presence of some of these molecules in the same cells creates good conditions for their interaction at the signaling level. The broad spectrum of actions allows for the engagement of angiotensin peptides, AVP, and insulin in the regulation of the most vital cardiac processes, including (1) cardiac tissue oxygenation, energy production, and metabolism; (2) the generation of the other cardiovascular compounds, such as nitric oxide, bradykinin (Bk), and endothelin; and (3) the regulation of cardiac work by the autonomic nervous system and the cardiovascular neurons of the brain. Multiple experimental studies and clinical observations show that the interactions of Ang II, Ang(1-7), AVP, and insulin in the heart and in the brain are markedly altered during heart failure, hypertension, obesity, and diabetes mellitus, especially when these diseases coexist. A survey of the literature presented in the review provides evidence for the belief that very individualized treatment, including interactions of angiotensins and vasopressin with insulin, should be applied in patients suffering from both the cardiovascular and metabolic diseases.

Pre-diabetes is associated with attenuation rather than volume of epicardial adipose tissue on computed tomography

The volume of epicardial adipose tissue (EATV) is increased in type-2 diabetes (T2D), while its attenuation (EATA) appears to be decreased. Similar patterns have been suggested in pre-diabetes, but data is scarce. In both pre-diabetes and T2D, any independent role of EATV and EATA in disease development remains to be proven, a task complicated by their substantial co-variation with other anthropometrics, e.g. BMI, waist circumference, and abdominal visceral adipose tissue (VAT). EATV and EATA was quantified in computed tomography (CT) images in a population study (n = 1948) using an automatic technique. Data was available on BMI, waist circumference, abdominal visceral adipose tissue (VAT) area, insulin resistance (IR) and glucose tolerance, the latter ranging from normal (NGT), over pre-diabetes (impaired fasting glucose [IFG, n = 414] impaired glucose tolerance [IGT, n = 321] and their combination [CGI, n = 128]), to T2D. EATV was increased in pre-diabetes, T2D and IR in univariable analyses and when adjusting for BMI, however not when adjusting for waist or VAT. EATA was reduced in pre-diabetes, T2D and IR in univariable analyses and when adjusting for BMI and waist, however not when adjusting for VAT. Adjustment for other co-variates had little influence on the results. In conclusion, EATV is increased and EATA reduced in pre-diabetes, T2D and IR, however, significant co-variation with other anthropometrics, especially VAT, obscures their function in disease development. The current results do not exclude a pathophysiological role of epicardial fat, but future studies need to adjust for anthropometrics, or focus on the microenvironment within the pericardial sac.

Long-term association of pericardial adipose tissue with incident diabetes and prediabetes: the Coronary Artery Risk Development in Young Adults Study

OBJECTIVES

We examined whether pericardial adipose tissue (PAT) is predictive of prediabetes and type 2 diabetes over time.

METHODS

In total, 2,570 adults without prediabetes/diabetes from the Coronary Artery Risk Development in Young Adults Study were followed up over 15 years. PAT volume was measured by computed tomography scans, and the new onset of prediabetes/diabetes was examined 5 years, 10 years, and 15 years after the PAT measurements. Multivariable Cox regression models were used to examine the association between the tertile of PAT and incident prediabetes/diabetes up to 15 years later. The predictive ability of PAT (vs. waist circumference [WC], body mass index [BMI], waist-to-height ratio [WHtR]) for prediabetes/diabetes was examined by comparing the area under the receiver operating characteristic curve (AUC).

RESULTS

The highest tertile of PAT was associated with a 1.56 times (95% confidence interval [CI], 1.03 to 2.34) higher rate of diabetes than the lowest tertile; however, no association was found between the highest tertile of PAT and prediabetes in the fully adjusted models, including additional adjustment for BMI or WC. In the fully adjusted models, the AUCs of WC, BMI, WHtR, and PAT for predicting diabetes were not significantly different, whereas the AUC of WC for predicting prediabetes was higher than that of PAT.

CONCLUSIONS

PAT may be a significant predictor of hyperglycemia, but this association might depend on the effect of BMI or WC. Additional work is warranted to examine whether novel adiposity indicators can suggest advanced and optimal information to supplement the established diagnosis for prediabetes/diabetes.

Both epicardial and peri-aortic adipose tissue blunt heart rate recovery beyond body fat mass

Background

Epicardial adipose tissue (EAT) as a marker of metabolic disorders has been shown to be closely associated with a variety of unfavorable cardiovascular events and cardiac arrhythmias. Data on regional-specific visceral adiposity outside the heart and its modulation on autonomic dysfunction, particularly heart rate recovery after exercise, remain obscure.

Methods

We studied 156 consecutive subjects (mean age: 49.3 ± 8.0 years) who underwent annual health surveys and completed treadmill tests. Multi-detector computed tomography-based visceral adiposity, including EAT and peri-aortic fat (PAF) tissue, was quantified using dedicated software (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). We further correlated EAT and PAF with blood pressure and heart rate (HR) recovery information from an exercise treadmill test. Metabolic abnormalities were scored by anthropometrics in combination with biochemical data.

Results

Increased EAT and PAF were both associated with a smaller reduction in systolic blood pressure during the hyperventilation stage before exercise compared to supine status (β-coefficient (coef.): −0.19 and −0.23, respectively, both p < 0.05). Both visceral adipose tissue mediated an inverted relationship with heart rate recovery at 3 (EAT: β-coef.: −0.3; PAF: β-coef.: −0.36) and 6 min (EAT: β-coef.: −0.32; PAF: β-coef.: −0.34) after peak exercise, even after adjusting for baseline clinical variables and body fat composition (all p < 0.05).

Conclusion

Excessive visceral adiposity, whether proximal or distal to the heart, may modulate the autonomic response by lowering the rate of HR recovery from exercise after accounting for clinical metabolic index. Cardiac autonomic dysfunction may partly explain the increase in cardiovascular morbidity and mortality related to both visceral fats.

Associations of the Mediterranean-Style Dietary Pattern Score with Coronary Artery Calcification and Pericardial Adiposity in a Sample of US Adults

Several studies have identified improvements in the risks of cardiovascular disease in adults following a Mediterranean dietary pattern. However, data are scarce on its association with coronary artery calcification (CAC) and pericardial adiposity (PAT) in US adults with and without diabetes. To address this gap, we conducted a case-control study using baseline data from the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study [n = 1255; Type 1 Diabetes (T1D): n = 563; non-Diabetes Mellitus (non-DM): n = 692]. Participants completed a validated food frequency questionnaire, fasting (12 h overnight fast) biochemical analyses, and a physical examination including anthropometric measures. CAC and PAT were measured using electron beam-computed tomography. Logistic regression models were used to examine the associations of the Mediterranean-Style Dietary Pattern Score (MSDPS) with CAC (presence or absence), and linear regression models were applied to PAT analyses. In all of the adjusted models, no significant associations with CAC were found. For PAT, an increasing MSDPS was consistently associated with its lower volume in models adjusted for age, sex, diabetes status, total calories, and body mass index (all p < 0.05). The association between MSDPS and PAT was attenuated after adjusting for serum lipids and physical activity. In conclusion, the baseline data from the CACTI study show that a greater adherence to MSDPS is associated with a lower PAT volume and provide evidence that the Mediterranean dietary pattern is associated with lower cardiovascular risk markers.

Association of Region-Specific Cardiac Adiposity With Dysglycemia and New-Onset Diabetes

Background Visceral adipose tissue is assumed to be an important indicator for insulin resistance and diabetes beyond overweight/obesity. We hypothesized that region-specific visceral adipose tissue may regulate differential biological effects for new-onset diabetes regardless of overall obesity. Methods and Results We quantified various visceral adipose tissue measures, including epicardial adipose tissue, paracardial adipose tissue, interatrial fat, periaortic fat, and thoracic aortic adipose tissue in 1039 consecutive asymptomatic participants who underwent multidetector computed tomography. We explored the associations of visceral adipose tissue with baseline dysglycemic indices and new-onset diabetes. Epicardial adipose tissue, paracardial adipose tissue, interatrial fat, periaortic fat, and thoracic aortic adipose tissue were differentially and independently associated with dysglycemic indices (fasting glucose, postprandial glucose, HbA1c, and homeostasis model assessment of insulin resistance) beyond anthropometric measures. The superimposition of interatrial fat and thoracic aortic adipose tissue on age, sex, body mass index, and baseline homeostasis model assessment of insulin resistance expanded the likelihood of baseline diabetes (from 67.2 to 86.0 and 64.4 to 70.8, P for ∆ ꭕ²: <0.001 and 0.011, respectively). Compared with the first tertile, the highest interatrial fat tertile showed a nearly doubled risk for new-onset diabetes (hazard ratio, 2.09 [95% CI, 1.38-3.15], P<0.001) after adjusting for Chinese Visceral Adiposity Index. Conclusions Region-specific visceral adiposity may not perform equally in discriminating baseline dysglycemia or diabetes, and showed differential predictive performance in new-onset diabetes. Our data suggested that interatrial fat may serve as a potential marker for new-onset diabetes.

Development of a nomogram for predicting the risk of left ventricular diastolic function in subjects with type-2 diabetes mellitus

Left ventricular diastolic dysfunction (LVDD) can be affected by many factors, including epicardial adipose tissue (EAT), obesity and type-2 diabetes mellitus (T2DM). The aim of this study was to establish and validate an easy-to-use nomogram that predicts the severity of LVDD in patients with T2DM. This is a retrospective study of 84 consecutive subjects with T2DM admitted to the Endocrinology Department, the First People’s Hospital of Zunyi City between January 2015 and October 2020. Several echocardiographic characteristics were used to diagnose diastolic dysfunction according to the 2016 diastolic dysfunction ASE guidelines. Anthropometric, demographic, and biochemical parameters were collected. Through a least absolute shrinkage and selection operator (LASSO) regression model, we reduced the dimensionality of the data and determined factors for the nomogram. The mean follow-up was 25.97 months. Cases were divided into two groups, those with LVDD (31) and those without (53). LASSO regression identified total cholesterol (Tol.chol), low-density lipoprotein (LDL), right ventricular anterior wall (RVAW) and epicardial adipose tissue (EAT) were identified as predictive factors in the nomogram. The ROC curve analysis demonstrated that the AUC value for most clinical paramerters was higher than 0.6. The nomogram can be used to promote the individualized prediction of LVDD risk in T2DM patients, and help to prioritize patients diagnosed with echocardiography.

Plasma omega-3 and saturated fatty acids are differentially related to pericardial adipose tissue volume across race/ethnicity: the Multi-ethnic Study of Atherosclerosis

BACKGROUND:

Pericardial adipose tissue (PAT) is a cardiometabolic risk factor influenced by race/ethnicity, inflammation, and metabolic dysfunction. Omega-3 fatty acids (FAs) and saturated FAs (SFAs) are known to affect these latter phenomena and may influence PAT accumulation. We aimed to determine whether plasma levels of these FAs are related to PAT volume and its rate of change over a median 3-year follow-up.

METHODS:

Cardiac computed tomography assessed PAT in 6,785 Multi-Ethnic Study of Atherosclerosis participants. Gas chromatography flame-ionization estimated plasma phospholipid fatty acids. Regression analyses estimated associations of FAs with PAT volume and its rate of change with adjustments for other risk factors. Race-interactions were tested.

RESULTS:

In cross-section, top tertiles of omega-3 FAs and odd-chained SFAs were associated with 2.8 and 4.93 cm³ lower PAT volumes, respectively; race/ethnicity was a significant modifying variable (p<0.002). Even-chained SFAs were associated with 3.5 cm³ greater PAT volume. With stratification by race/ethnicity, Chinese Americans in the top tertile of omega-3 FAs showed 10.5 cm³ greater PAT volume than those in the referent tertile. Black individuals in the top tertile of odd-chained SFAs showed 5.0 cm³ lower PAT compared to referents. Black and Chinese Americans in top tertiles of even-chained SFAs showed respective 3.7 and 5.9 cm³ greater PAT volumes compared to referents. Two associations were observed in prospective analyses among Caucasians; race interactions were non-significant.

CONCLUSIONS:

Cross-sectional and prospective findings provide inconclusive evidence as to whether plasma FAs are related to PAT in healthy individuals. Cohort studies with longer follow-up periods are warranted.

Association of Pericardiac Adipose Tissue With Coronary Artery Disease

BACKGROUND AND AIM

Coronary artery disease (CAD) poses a worldwide health threat. Compelling evidence shows that pericardial adipose tissue (PAT), a brown-like adipose adjacent to the external surface of the pericardium, is associated with CAD. However, the specific molecular mechanisms of PAT in CAD are elusive. This study aims to characterize human PAT and explore its association with CAD.

METHODS

We acquired samples of PAT from 31 elective cardiac surgery patients (17 CAD patients and 14 controls). The transcriptome characteristics were assessed in 5 CAD patients and 4 controls via RNA-sequencing. Cluster profile R package, String database, Cytoscape were applied to analyze the potential pathways and PPI-network key to DEGS, whereas the hubgenes were predicted via Metascape, Cytohubba, and MCODE. We use Cibersort, ENCORI, and DGIDB to predict immunoinfiltration, mRNA-miRNA target gene network, and search potential drugs targeting key DEGs. The predictable hubgenes and infiltrating inflammatory cells were validated in 22 patients (12 CAD samples and 10 control samples) through RT-qPCR and immunohistochemistry.

RESULTS

A total of 147 different genes (104 up-regulated genes and 43 down-regulated genes) were identified in CAD patients. These different genes were associated with immunity and inflammatory dysfunction. Cibersort analysis showed monocytes and macrophages were the most common subsets in immune cells, whereas immunohistochemical results revealed there were more macrophages and higher proportion of M1 subtype cells in PAT of CAD patients. The PPI network and module analysis uncovered several crucial genes, defined as candidate genes, including Jun, ATF3, CXCR4, FOSB, CCl4, which were validated through RT-qPCR. The miRNA-mRNA network implicated hsa-miR-185-5p as diagnostic targets and drug-gene network showed colchicine, fenofibrate as potential therapeutic drugs, respectively.

CONCLUSION

This study demonstrates that PAT is mainly associated with the occurrence of CAD following the dysfunction of immune and inflammatory processes. The identified hubgenes, predicted drugs and miRNAs are promising biomarkers and therapeutic targets for CAD.

Pericardial fat and its influence on cardiac diastolic function

BACKGROUND

Pericardial fat (PF) has been suggested to directly act on cardiomyocytes, leading to diastolic dysfunction. The aim of this study was to investigate whether a higher PF volume is associated with a lower diastolic function in healthy subjects.

METHODS

254 adults (40-70 years, BMI 18-35 kg/m2, normal left ventricular ejection fraction), with (a)typical chest pain (otherwise healthy) from the cardiology outpatient clinic were retrospectively included in this study. All patients underwent a coronary computed tomographic angiography for the measurement of pericardial fat volume, as well as a transthoracic echocardiography for the assessment of diastolic function parameters. To assess the independent association of PF and diastolic function parameters, multivariable linear regression analysis was performed. To maximize differences in PF volume, the group was divided in low (lowest quartile of both sexes) and high (highest quartile of both sexes) PF volume. Multivariable binary logistic analysis was used to study the associations within the groups between PF and diastolic function, adjusted for age, BMI, and sex.

RESULTS

Significant associations for all four diastolic parameters with the PF volume were found after adjusting for BMI, age, and sex. In addition, subjects with high pericardial fat had a reduced left atrial volume index (p = 0.02), lower E/e (p < 0.01) and E/A (p = 0.01), reduced e' lateral (p < 0.01), reduced e' septal p = 0.03), compared to subjects with low pericardial fat.

CONCLUSION

These findings confirm that pericardial fat volume, even in healthy subjects with normal cardiac function, is associated with diastolic function. Our results suggest that the mechanical effects of PF may limit the distensibility of the heart and thereby directly contribute to diastolic dysfunction. Trial registration NCT01671930.

Perivascular adipose tissue in age-related vascular disease

Perivascular adipose tissue (PVAT), a crucial regulator of vascular homeostasis, is actively involved in vascular dysfunction during aging. PVAT releases various adipocytokines, chemokines and growth factors. In an endocrine and paracrine manner PVAT-derived factors regulate vascular signalling and inflammation modulating functions of adjacent layers of the vasculature. Pathophysiological conditions such as obesity, type 2 diabetes, vascular injury and aging can cause PVAT dysfunction, leading to vascular endothelial and smooth muscle cell dysfunctions. We and others have suggested that PVAT is involved in the inflammatory response of the vascular wall in diet induced obesity animal models leading to vascular dysfunction due to disappearance of the physiological anticontractile effect. Previous studies confirm a crucial role for pinpointed PVAT inflammation in promoting vascular oxidative stress and inflammation in aging, enhancing the risk for development of cardiovascular disease. In this review, we discuss several studies and mechanisms linking PVAT to age-related vascular diseases. An overview of the suggested roles played by PVAT in different disorders associated with the vasculature such as endothelial dysfunction, neointimal formation, aneurysm, vascular contractility and stiffness will be performed. PVAT may be considered a potential target for therapeutic intervention in age-related vascular disease.

Epicardial adipose tissue: an emerging biomarker of cardiovascular complications in type 2 diabetes?

Type 2 diabetes (T2D) is associated with an increased risk of cardiovascular disease and heart failure, which highlights the need for improved understanding of factors contributing to the pathophysiology of these complications as they are the leading cause of mortality in T2D. Patients with T2D have high levels of epicardial adipose tissue (EAT). EAT is known to secrete inflammatory factors, lipid metabolites, and has been proposed to apply mechanical stress on the cardiac muscle that may accelerate atherosclerosis, cardiac remodeling, and heart failure. High levels of EAT in patients with T2D have been associated with atherosclerosis, diastolic dysfunction, and incident cardiovascular events, and this fat depot has been suggested as an important link coupling diabetes, obesity, and cardiovascular disease. Despite this, the predictive potential of EAT in general, and in patients with diabetes, is yet to be established, and, up until now, the clinical relevance of EAT is therefore limited. Should this link be established, importantly, studies show that this fat depot can be modified both by pharmacological and lifestyle interventions. In this review, we first introduce the role of adipose tissue in T2D and present mechanisms involved in the pathophysiology of EAT and pericardial adipose tissue (PAT) in general, and in patients with T2D. Next, we summarize the evidence that these fat depots are elevated in patients with T2D, and discuss whether they might drive the high cardiometabolic risk in patients with T2D. Finally, we discuss the clinical potential of cardiac adipose tissues, address means to target this depot, and briefly touch upon underlying mechanisms and future research questions.

Mechanistic Links Between Obesity, Diabetes, and Blood Pressure: Role of Perivascular Adipose Tissue

Obesity is increasingly prevalent and is associated with substantial cardiovascular risk. Adipose tissue distribution and morphology play a key role in determining the degree of adverse effects, and a key factor in the disease process appears to be the inflammatory cell population in adipose tissue. Healthy adipose tissue secretes a number of vasoactive adipokines and anti-inflammatory cytokines, and changes to this secretory profile will contribute to pathogenesis in obesity. In this review, we discuss the links between adipokine dysregulation and the development of hypertension and diabetes and explore the potential for manipulating adipose tissue morphology and its immune cell population to improve cardiovascular health in obesity.

In New-Onset Diabetes Mellitus, Metformin Reduces Fat Accumulation in the Liver, But Not in the Pancreas or Pericardium

Background: Nonalcoholic fatty pancreas and liver disease (NAFPD and NAFLD) and pericardial adipose tissue (PAT) are often associated with type 2 diabetes mellitus (T2DM). Our aim was to evaluate the incidence rate of NAFLD and NAFPD, PAT size, and the effect of metformin treatment on NAFLD, NAFPD, and PAT in new-onset T2DM (NODM). Methods: Seventeen patients with NODM and 10 subjects used as a control group were involved in the study. Computed tomography (CT) and laboratory tests were performed before the beginning of metformin therapy and 4 months afterward. PAT and the amount of fat in the pancreas and liver were determined by X-ray attenuation during unenhanced CT examination and compared with the values for the control subjects. Results: Metabolic parameters improved significantly after metformin therapy. NAFLD was diagnosed in 64.7% of the patients with NODM and in 10% of the control subjects. The radiation absorption of the liver was significantly lower in the patients with NODM compared with the control group and significantly higher after metformin therapy compared with the baseline values. Only six patients (35.3%) had NAFLD after metformin therapy. NAFPD was diagnosed in 82.3% of the patients with NODM and in 20% of the control subjects. The radiation absorption of the pancreas was significantly lower in the patients with NODM compared with the control group but did not change significantly after treatment. PAT size was significantly larger in the patients with NODM and did not change significantly after metformin treatment. Conclusions: NAFLD, NAFPD, and increased PAT were detected in the majority of patients with NODM. Metformin therapy decreased the amount of fat in the liver in parallel with an improvement in the metabolic parameters and may, thus, be beneficial for preventing the late consequences of NAFLD.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Exercise Training Reduces Intrathoracic Fat Regardless of Defective Glucose Tolerance

Purpose

Epicardial (EAT) and pericardial (PAT) fat masses and myocardial triglyceride content (MTC) are enlarged in obesity and insulin resistance. We studied whether the high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) similarly decrease ectopic fat in and around the heart and whether the decrease is similar in healthy subjects and subjects with defective glucose tolerance (DGT).

Methods

A total of 28 healthy men (body mass index = 20.7–30.0 kg·m⁻², age = 40–55 yr) and 16 men with DGT (body mass index = 23.8–33.5 kg·m⁻², age = 43–53 yr) were randomized into HIIT and MICT interventions for 2 wk. EAT and PAT were determined by computed tomography and MTC by ¹H-MRS.

Results

At baseline, DGT subjects had impaired aerobic capacity and insulin sensitivity and higher levels of whole body fat, visceral fat, PAT, and EAT (P < 0.05, all) compared with healthy subjects. In the whole group, HIIT increased aerobic capacity (HIIT = 6%, MICT = 0.3%; time × training P = 0.007) and tended to improve insulin sensitivity (HIIT = 24%, MICT = 8%) as well as reduce MTC (HIIT = −42%, MICT = +23%) (time × training P = 0.06, both) more efficiently compared with MICT, and without differences in the training response between the healthy and the DGT subjects. However, both training modes decreased EAT (−5%) and PAT (−6%) fat (time P < 0.05) and not differently between the healthy and the DGT subjects.

Conclusion

Whole body fat, visceral fat, PAT, and EAT masses are enlarged in DGT. Both HIIT and MICT effectively reduce EAT and PAT in healthy and DGT subjects, whereas HIIT seems to be superior as regards improving aerobic capacity, whole-body insulin sensitivity, and MTC.

The ratio of pericardial to subcutaneous adipose tissues is associated with insulin resistance

OBJECTIVE

To examine the association between pericardial adipose tissue (PAT) and the ratio of PAT to subcutaneous adipose tissue (SAT) with insulin resistance in adults with and without type 1 diabetes (T1D).

METHODS

Data for this report came from a substudy of the Coronary Artery Calcification in Type 1 Diabetes cohort (n = 83; 38 with T1D, 45 without T1D). Insulin resistance was measured by hyperinsulinemic-euglycemic clamp. Abdominal computed tomography (CT) was used to measure visceral adipose tissue (VAT) and SAT. PAT was measured from CT scans of the heart.

RESULTS

PAT and the ratio of PAT to SAT was higher in males compared to females. After adjustment for demographics, diabetes, blood pressure and lipid factors, BMI, VAT, and log PAT/SAT ratio, log PAT was positively associated with the glucose infusion rate (GIR) in females only (β = 3.36 ± 1.96, P = 0.097, P for sex interaction = 0.055). Conversely, the log PAT/SAT ratio was significantly associated with decreased GIR in both males and females (β = -2.08 ± 1.03, P = 0.047, P for sex interaction = 0.768).

CONCLUSIONS

A significant association between the PAT/SAT ratio and insulin resistance was found, independent of BMI, VAT, and PAT. These results highlight the importance of considering fat distribution independent of volume.

Epicardial, pericardial and total cardiac fat and cardiovascular disease in type 2 diabetic patients with elevated urinary albumin excretion rate

Background We evaluated the association of cardiac adipose tissue including epicardial adipose tissue and pericardial adipose tissue with incident cardiovascular disease and mortality, coronary artery calcium, carotid intima media thickness and inflammatory markers. Design A prospective study of 200 patients with type 2 diabetes and elevated urinary albumin excretion rate (UAER). Methods Cardiac adipose tissue was measured from baseline echocardiography. The composite endpoint comprised incident cardiovascular disease and all-cause mortality. Coronary artery calcium, carotid intima media thickness and inflammatory markers were measured at baseline. Cardiac adipose tissue was investigated as continuous and binary variable. Analyses were performed unadjusted (model 1), and adjusted for age, sex (model 2), body mass index, low-density lipoprotein cholesterol, smoking, glycated haemoglobin, and systolic blood pressure (model 3). Results Patients were followed-up after 6.1 years for non-fatal cardiovascular disease ( n = 29) or mortality ( n = 23). Cardiac adipose tissue ( p = 0.049) and epicardial adipose tissue ( p = 0.029) were associated with cardiovascular disease and mortality in model 1. When split by the median, patients with high cardiac adipose tissue had a higher risk of cardiovascular disease and mortality than patients with low cardiac adipose tissue in unadjusted (hazard ratio 1.9, confidence interval: 1.1; 3.4, p = 0.027) and adjusted (hazard ratio 2.0, confidence interval: 1.1; 3.7, p = 0.017) models. Cardiac adipose tissue ( p =  0.033) was associated with baseline coronary artery calcium (model 1) and interleukin-8 (models 1-3, all p < 0.039). Conclusions In type 2 diabetes patients without coronary artery disease, high cardiac adipose tissue levels were associated with increased risk of incident cardiovascular disease or all-cause mortality even after accounting for traditional cardiovascular disease risk factors. High cardiac adipose tissue amounts were associated with subclinical atherosclerosis (coronary artery calcium) and with the pro-atherogenic inflammatory marker interleukin-8.

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.

Higher pericardial adiposity is associated with prevalent diabetes: The Coronary Artery Risk Development in Young Adults study

BACKGROUND AND AIMS

Pericardial adipose tissue (PAT) is located on both sides of the pericardium. We tested whether PAT was associated with prevalent diabetes at the year 25 exam of the Coronary Artery Risk Development in Young Adults (CARDIA) study.

METHODS AND RESULTS

The CARDIA Year 25 exam (2010-2011) included complete data for all covariates on 3107 participants. Prevalent diabetes (n = 436) was defined as high fasting (≥126 mg/dl) or 2-h postload glucose (≥200 mg/dl) or HbA1c (≥6.5%) or use of diabetes medications. Volume of PAT was measured from computed tomographic scans. Logistic regression was performed to examine the relationship between quartiles of PAT and diabetes. In regression models adjusted for field center, sex, race, age, systolic blood pressure, total cholesterol, log triglycerides, and treatment with blood pressure and cholesterol lowering medication, PAT volume in the 4th quartile was significantly associated with diabetes status after adjustment for BMI (OR 2.57, 95% CI 1.66, 3.98) or visceral adipose tissue (OR 2.08, 95% CI 1.32, 3.29). PAT volume in the 2nd and 3rd quartiles was not significantly associated with diabetes status relative to the first quartile.

CONCLUSIONS

Metabolically active pericardial adipose tissue is associated with prevalent diabetes only at higher volumes independent of overall obesity.

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.

Relation between ADIPOQ gene polymorphisms and type 2 diabetes in a Chinese population

OBJECTIVE

We aimed to investigate the relation between adiponectin gene (ADIPOQ) polymorphisms and type 2 diabetes mellitus (T2DM) in a Chinese population.

METHODS

The present study included 510 subjects with normal glucose tolerant (NGT) and 510 patients with type 2 diabetic. Five SNPs (rs2241767, rs3821799, rs182052, rs1501299 and rs7627128) were genotyped by TaqMan methods.

RESULTS

Of these 5 SNPs, three SNPs (rs1501299, rs182052, and rs7627128) were found to be significantly associated with T2DM. The haplotypes AAT (Construction of rs1501299, rs182052, and rs7627128) was frequent in T2DM patients (OR=2.051, 95% CI: 1.439~2.923, P<0.001), but GAT (Construction of rs1501299, rs182052, and rs7627128) was frequent in the control group (OR=0.65, 95% CI: 0.540~0.805, P<0.001).

CONCLUSION

The ADIPOQ gene variants and haplotype were associated with the risk for development of type 2 diabetes.

Cardiac adipose tissue and its relationship to diabetes mellitus and cardiovascular disease

Type-2 diabetes mellitus (T2DM) plays a central role in the development of cardiovascular disease (CVD). However, its relationship to epicardial adipose tissue (EAT) and pericardial adipose tissue (PAT) in particular is important in the pathophysiology of coronary artery disease. Owing to its close proximity to the heart and coronary vasculature, EAT exerts a direct metabolic impact by secreting proinflammatory adipokines and free fatty acids, which promote CVD locally. In this review, we have discussed the relationship between T2DM and cardiac fat deposits, particularly EAT and PAT, which together exert a big impact on the cardiovascular health.

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.