Determinants of intrathoracic adipose tissue volume and associations with cardiovascular disease risk factors in Amish

Association of ectopic fat with abdominal aorto-illiac and coronary artery calcification in african ancestry men

BACKGROUND AND AIMS

There is strong evidence that fat accumulating in non-adipose sites, "ectopic fat", is associated with cardiovascular disease (CVD), including vascular calcification. Most previous studies of this association have assessed only a single ectopic fat depot. Therefore, our aim was to assess the association of total, regional, and ectopic fat with abdominal aorto-illiac calcification (AAC) and coronary artery calcification (CAC) in 798 African ancestry men.

METHODS

Participants (mean age 62) were from the Tobago Bone Health Study cohort. Adiposity was assessed via clinical examination, dual x-ray absorptiometry, and computed tomography (CT). Ectopic fat depots included: abdominal visceral adipose tissue (VAT), liver attenuation, and calf intermuscular adipose tissue (IMAT). Vascular calcification was assessed by CT and quantified as present versus absent. Associations were tested using multiple logistic regression adjusted for traditional cardiovascular risk factors. Models of ectopic fat were additionally adjusted for total body fat and standing height.

RESULTS

All adiposity measures, except VAT, were associated with AAC. Lower liver attenuation or greater calf IMAT was associated with 1.2-1.3-fold increased odds of AAC (p < 0.03 for both), though calf IMAT was a stronger predictor than liver attenuation (p < 0.001) when entered in a single model. No ectopic fat measure was associated with CAC.

CONCLUSIONS

Greater adiposity in the skeletal muscle and liver, but not in the visceral compartment, was associated with increased odds of AAC in African ancestry men. These results highlight the potential importance of both quantity and location of adiposity accumulation throughout the body.

Mouse P2Y4 Nucleotide Receptor Is a Negative Regulator of Cardiac Adipose-Derived Stem Cell Differentiation and Cardiac Fat Formation

Cardiac adipose tissue-derived stem cells (cASCs) have the ability to differentiate into multiple cell lineages giving them a high potential for use in regenerative medicine. Cardiac fat tissue still raises many unsolved questions related to its formation and features. P2Y nucleotide receptors have already been described as regulators of differentiation of bone-marrow derived stem cells, but remain poorly investigated in cASCs. We defined, in this study, the P2Y₄ nucleotide receptor as a negative regulator of cardiac fat formation and cASC adipogenic differentiation. Higher expression of P2Y₄ receptor in cardiac fat tissue was observed compared to other adipose tissues. P2Y₄-null mice displayed a higher mass of cardiac adipose tissue specifically. We therefore examined the role of P2Y₄ receptor in cASC adipogenic differentiation. An inhibitory effect of uridine 5'-triphosphate (UTP), ligand of P2Y₄, was observed on the maturation state of differentiated cASCs, and on the expression of adipogenesis-linked genes and adiponectin, a cardioprotective adipokine. Higher adiponectin secretion by P2Y₄-null adipocytes could be linked with cardioprotection previously observed in the heart of P2Y₄-null ischemic mice. We realized here left anterior descending artery ligation on simple and double-knockout mice for P2Y₄ and adiponectin. No cardioprotective effect of P2Y₄ loss was observed in the absence of adiponectin secretion. In addition, P2Y₄ loss was correlated with higher expression of UCP-1 (uncoupling protein-1) and CD137, two markers of brown/beige cardiac adipocytes. Our data highlight the P2Y₄ receptor as an inhibitor of cardiac fat formation and cASC adipogenic differentiation, and as a potential therapeutic target in the regulation of cardioprotective function of cardiac fat.

Epicardial fat accumulation, cardiometabolic profile and cardiovascular events in patients with stages 3-5 chronic kidney disease

BACKGROUND

It has been hypothesized that epicardial adipose tissue (EAT) exerts pathogenic effects on cardiac structures. We analysed the associations between EAT and both cardiovascular (CV) disease risk factors and CV events in patients with chronic kidney disease (CKD).

PATIENTS AND METHODS

We included 277 nondialysed patients [median age 61, interquartile range (IQR) 53-68 years; 63% men] with stages 3-5 CKD in this cross-sectional evaluation. EAT and abdominal visceral adipose tissue (VAT) were assessed by computed tomography. Patients were followed for median 32 (IQR 20-39) months, and the composite of fatal and nonfatal CV events was recorded.

RESULTS

With increasing EAT quartiles, patients were older, had higher glomerular filtration rate, body mass index, waist, VAT and coronary calcification, higher levels of haemoglobin, triglycerides, albumin, C-reactive protein and leptin and higher prevalence of left ventricular hypertrophy and myocardial ischaemia; total and high-density lipoprotein cholesterol, 25-hydroxy-vitamin D and 1, 25-dihydroxy-vitamin D progressively decreased. Associations between EAT and cardiac alterations were not independent of VAT. During follow-up, 58 CV events occurred. A 1-SD higher EAT volume was associated with an increased risk of CV events in crude [hazard ratio (HR) 1.41, 95% confidence interval (CI) (1.12-1.78) and adjusted (HR 1.55, 95% CI 1.21-1.99) Cox models. However, adding EAT to a standard CV disease risk prediction model did not result in a clinically relevant improvement in prediction.

CONCLUSION

Epicardial adipose tissue accumulation in patients with CKD increases the risk of CV events independent of general adiposity. This is consistent with the notion of a local pathogenic effect of EAT on the heart or heart vessels, or both. However, EAT adds negligible explanatory power to standard CV disease risk factors.