ABSTRACT
CONTEXT: Subcutaneous adipose tissue (SAT) is not homogeneous, as the fascia scarpa separates the deep SAT (dSAT) from the superficial SAT (sSAT). OBJECTIVE: The aim of this study is to evaluate the sex-specific associations of sSAT and dSAT with hepatic steatosis and metabolic syndrome in overweight individuals. METHODS: We recruited 285 individuals with a body mass index (BMI) greater than or equal to 27 and aged 55 to 81 years. Abdominal magnetic resonance imaging was performed around level L4 to L5 to measure visceral adipose tissue (VAT), dSAT, and sSAT volumes. The amount of hepatic fat was quantified by MR spectroscopy. RESULTS: Men had significantly higher volumes of VAT (122.6 cm3 vs 98.7 cm3, Pâ <â .001) and had only half the volume of sSAT compared to women adjusted for BMI (50.3 cm3 in men vs 97.0 cm3 in women, Pâ <â .001). dSAT correlated significantly with hepatic fat content in univariate analysis (standardized ßâ =â .190, Pâ <â .05), while VAT correlated significantly with hepatic steatosis in a multivariate model, adjusted for age, alcohol use, and other abdominal fat compartments (standardized ßâ =â .184, Pâ =â .037). Moreover, dSAT in men correlated negatively with HDL cholesterol (standardized ßâ =â -0.165, Pâ =â .038) in multivariate analyses. In women with a BMI between 30 and 40, in a multivariate model adjusted for age, alcohol use, and other abdominal fat compartments, VAT correlated positively (standardized ßâ =â -.404, Pâ =â .003), and sSAT negatively (standardized ßâ =â -.300, Pâ =â .04) with hepatic fat content. CONCLUSION: In men, dSAT is associated with hepatic steatosis and adverse metabolic traits, such as lower HDL cholesterol levels, whereas in women with obesity sSAT shows a beneficial relation with respect to hepatic fat content.
Subject(s)
Fatty Liver/etiology , Intra-Abdominal Fat/pathology , Metabolic Syndrome/etiology , Subcutaneous Fat, Abdominal/pathology , Aged , Aged, 80 and over , Cohort Studies , Fatty Liver/diagnosis , Fatty Liver/epidemiology , Fatty Liver/pathology , Female , Humans , Intra-Abdominal Fat/diagnostic imaging , Intra-Abdominal Fat/metabolism , Magnetic Resonance Imaging , Male , Metabolic Syndrome/diagnosis , Metabolic Syndrome/epidemiology , Metabolic Syndrome/pathology , Middle Aged , Obesity/diagnosis , Obesity/epidemiology , Obesity/metabolism , Obesity/pathology , Organ Size/physiology , Overweight/diagnosis , Overweight/epidemiology , Overweight/metabolism , Overweight/pathology , Risk Factors , Sex Characteristics , Sex Factors , Subcutaneous Fat/diagnostic imaging , Subcutaneous Fat/metabolism , Subcutaneous Fat/pathology , Subcutaneous Fat, Abdominal/diagnostic imaging , Subcutaneous Fat, Abdominal/metabolismABSTRACT
Hirundo is the most species-rich genus of the passerine swallow family (Hirundinidae) and has a cosmopolitan distribution. Here we report the complete, annotated mitochondrial genomes for 25 individuals from 10 of the 14 extant Hirundo species; these include representatives from four subspecies of the barn swallow, H. rustica. Mitogenomes were conserved in size, ranging from 18,500 to 18,700 base pairs. They all contained 13 protein-coding regions, 22 tRNAs, a control region, and large and small ribosomal subunits. Phylogenetic analysis resolved most of the relationships between the studied species and subspecies which were largely consistent with previously published trees. Several new relationships were observed within the phylogeny that could have only been discovered with the increased amount of genetic material. This study represents the largest Hirundo mitochondrial phylogeny to date, and could serve as a vital tool for other studies focusing on the evolution of the Hirundo genus.
