Relation of epicardial fat and alanine aminotransferase in subjects with increased visceral fat.

BACKGROUND: Increased visceral adipose tissue (VAT) is a risk factor for an unfavorable cardio-metabolic profile and fatty liver. Individuals with human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART) can be associated with metabolic syndrome (MS) and higher visceral fat. However, the potential link between cardiac adiposity, emerging index of visceral adiposity, and fatty liver is still unexplored.
OBJECTIVE: To evaluate whether echocardiographic epicardial adipose tissue, index of cardiac adiposity, could be related to serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, surrogate markers of fatty liver, in HIV-infected patients with (HIV+MS+) and without HAART-associated MS (HIV+MS-). METHODS AND PROCEDURES: This was a cross-sectional observational study on 57 HIV+MS+ patients, 52 HIV+MS- and 57 HIV-negative subjects with MS (HIV-MS+), as control group. Epicardial fat thickness and intra-abdominal VAT were obtained by echocardiography and magnetic resonance imaging (MRI), respectively. Serum ALT and AST activity, plasma adiponectin levels, and MS biochemical parameters were measured.
RESULTS: Echocardiographic epicardial fat thickness was correlated with MRI-VAT (r = 0.83, P < 0.01), AST/ALT ratio (r = 0.77, P < 0.01), ALT (r = 0.58, P < 0.01), AST (r = 0.56, P < 0.01), and adiponectin (r = -0.45, P < 0.01) in HIV+MS+. MRI-VAT and AST/ALT ratio were the best correlates of epicardial fat thickness (r (2) = 0.45, P < 0.01). DISCUSSION: This study shows for the first time a clear relationship of epicardial fat, index of cardiac and visceral adiposity, and serum ALT and AST activity, markers of fatty liver, in subjects with increased visceral adiposity and cardio-metabolic risk. This correlation seems to be independent of overall adiposity and rather function of excess visceral adiposity.