Worsening of Obesity and Metabolic Status Yields Similar Molecular Adaptations_Subcutaneous and Visceral Adipose Tissue

Context: It is not known whether biological differences reported between subcutaneous (SAT) and visceral (VAT) adipose tissue depots underlie the pathogenicity of visceral fat. Objective: We compared SAT and VAT gene expression according to obesity, visceral fat accumulation, insulin resistance and presence of the metabolic syndrome. Design: Subjects were assigned into 4 groups (lean, overweight, obese and obese with metabolic syndrome). Setting: Subjects were recruited at a university hospital. Patients: 32 women were included. Main Outcome Measures: Anthropometric measurements, euglycemic hyperinsulinemic clamps, blood analyses and computed tomography scans were performed and paired samples of SAT and VAT were obtained for DNA microarray-based gene expression profiling. Whole transcriptome analysis was performed using DNA microarrays on subcutaneous and visceral adipose tissue of the selected 8 subjects per group (lean, overweight, obese and obese with metabolic syndrome). A total of 64 array hybridizations were performed. Cy5 dye was incorporated into adipose tissue RNA samples while a reference RNA pool made of a mix of commercial human liver, adipose tissue and skeletal muscle RNA was labelled with Cy3 dye (Applied Biosystems/Ambion). Samples were hybridized to Agilent 44k whole human genome microarrays with over 41,000 60-mer oligonucleotides from unique human sequences and transcripts.