Epicardial adipose tissue, hepatic steatosis and obesity

Abstract

Human hepatic lipase (hHL) is mainly localized on the hepatocyte cell surface where it hydrolyzes lipids from remnant lipoproteins and high density lipoproteins and promotes their hepatic selective uptake. Furthermore, hepatic lipase (HL) is closely associated with obesity in multiple studies. Therefore, HL may play a key role on lipid homeostasis in liver and white adipose tissue (WAT). In the present study, we aimed to evaluate the effects of hHL expression on hepatic and white adipose triglyceride metabolism in vivo. Experiments were carried out in hHL transgenic and wild-type mice fed a Western-type diet. Triglyceride metabolism studies included β-oxidation and de novo lipogenesis in liver and WAT, hepatic triglyceride secretion, and adipose lipoprotein lipase (LPL)-mediated free fatty acid (FFA) lipolysis and influx. The expression of hHL promoted hepatic triglyceride accumulation and de novo lipo-genesis without affecting triglyceride secretion, and this was associated with an upregula-tion of Srebf1 as well as the main genes controlling the synthesis of fatty acids. Transgenic mice also exhibited more adiposity and an increased LPL-mediated FFA influx into the WAT without affecting glucose tolerance. Our results demonstrate that hHL promoted hepatic steatosis in mice mainly by upregulating de novo lipogenesis. HL also upregulated WAT LPL and promoted triglyceride-rich lipoprotein hydrolysis and adipose FFA uptake. These data support the important role of hHL in regulating hepatic lipid homeostasis and confirm the broad cardiometabolic role of HL.

Threshold value of subepicardial adipose tissue to detect insulin resistance in obese children

“…In a few studies, an association between echocardiographic SAT thickness and insulin resistance has been reported in obese adult patients. 8,20 Another adult study indicated that higher SAT thickness is associated with impaired fasting glucose in non-diabetic men and women. 9 In another study, Iacobellis et al showed that echocardiographic SAT thickness correlated significantly in multivariate analysis with waist circumference, DBP and fasting insulin, although TGs and HDL cholesterol were not independently related to SAT thickness.…”

Insulin Signaling and Heart Failure

“…Perivascular adipose tissue (PVAT) surrounds the blood vessels. EAT mass and diameter are increased in obesity 109, 110 , and the volume of PVAT is associated with visceral obesity 111 . Neither, EAT nor PVAT, are separated by a fascial layer from the surrounding tissue.…”

Epicardial adipose tissue: at the heart of the obesity complications

“…EAT mass and thickness are increased in obesity [28], showing a stronger correlation with abdominal fat accumulation [29]. Increased EAT thickness or volume has also been shown to correlate with components of the metabolic syndrome, including fasting plasma glucose and insulin levels, insulin resistance (assessed by euglycemic hyperinsulinemic clamp or surrogate indices like HOMA and QUICKI), atherogenic lipid profile and systolic blood pressure [30,31].…”